Method and apparatus for digital printing
11707943 · 2023-07-25
Assignee
Inventors
- Moshe Levanon (Rehovot, IL)
- Tal Shimony-Cohen (Nes Ziona, IL)
- Yelena Yusupov (Holon, IL)
- Natalia Zlotnikov (Rehovot, IL)
Cpc classification
C09D11/40
CHEMISTRY; METALLURGY
B41M5/0023
PERFORMING OPERATIONS; TRANSPORTING
B41J2/2114
PERFORMING OPERATIONS; TRANSPORTING
B41J2002/012
PERFORMING OPERATIONS; TRANSPORTING
B41M5/0256
PERFORMING OPERATIONS; TRANSPORTING
C09D11/107
CHEMISTRY; METALLURGY
International classification
B41M5/025
PERFORMING OPERATIONS; TRANSPORTING
B41M5/00
PERFORMING OPERATIONS; TRANSPORTING
B41M7/00
PERFORMING OPERATIONS; TRANSPORTING
C09D11/107
CHEMISTRY; METALLURGY
C09D11/40
CHEMISTRY; METALLURGY
Abstract
A method of indirect digital printing is disclosed herein. The method employs (i) first (e.g. transparent) and second aqueous ink components (comprising colorant particles) and (ii) a target surface (e.g. hydrophobic) of an intermediate transfer member (ITM). A quantity of first ink component is deposited (e.g. by ink-jetting) onto the target surface and partially dried to produce a partially-dried layer thereon. Droplets of the second ink component are deposited onto the partially-dried layer of first ink component to form a wet, colored ink-image. Upon deposition of the droplets of the second ink component, the colorant particles from the second component penetrate into the partially-dried layer of the first ink component. The wet, colored image is dried into a tacky ink-image-bearing residue film which is transferred to the substrate. Physical and/or chemical properties of the first and second ink components as provided by various embodiments are disclosed herein.
Claims
1. A method of printing a digital image on a printing substrate using an intermediate transfer member (ITM), the method comprising: a. providing: i. a first aqueous ink component; and ii. a second aqueous ink component comprising colorant particles; b. delivering a quantity of the first ink component to a target surface of the ITM, to cover a portion of the target surface with a wet volume of the first ink component; c. effecting only a partial drying of the wet volume to produce a partially-dried layer of the first ink component on the ITM; d. digitally depositing droplets of the second ink component onto the partially-dried layer of the first component so as to form a wet, colored ink-image on the ITM, wherein the partially-dried layer of the first ink component is sufficiently moist and permeable such that at least 50% the colorant particles of the second ink component penetrate into the partially-dried layer of the first ink component; e. at least partially drying the wet, colored ink-image; f. transferring the at least partially dried ink-image from the ITM to printing substrate.
2. The method of claim 1 wherein the at least partially dried ink-image is tacky upon transfer from the ITM in step (f).
3. The method of claim 1 wherein the drying of step (e) is performed at least in part by heating and/or the at least partially dried ink-image is heated on the ITM before the transfer.
4. The method of claim 1 wherein (i) the at least partial drying is performed to produce a dried, tacky ink-image-bearing residue film; and (ii) the dried, tacky ink-image-bearing residue film is transferred from the ITM to the printing substrate in step (f).
5. The method of claim 1, wherein the first aqueous ink component that is provided in step (a) is transparent.
6. The method of claim 1, wherein the second component is delivered in step (d) by ink-jetting, and wherein during ink-jetting of the second ink component and under jetting conditions, the second aqueous ink component is a resoluble ink component.
7. The method of claim 1, wherein at least 70% of the colorant particles of the second ink component penetrate into and mixed with the partially-dried layer of the first ink component.
8. The method of claim 1, wherein: A. upon transfer from the ITM, a temperature of the least partially dried ink-image is T.sub.Transfer; B. a dry film glass transition temperature T.sub.g.sup.dry_film([2.sup.nd component]) of the second ink component exceeds the transfer temperature T.sub.TRANSFER by at least 5° C.; and C. a dry film glass transition temperature T.sub.g.sup.dry_film([5:1 2.sup.nd component: 1.sup.st component]) of a 5:1 weight-ratio of the first and second components is less than the transfer temperature T.sub.TRANSFER by at least 5° C.
9. The method of claim 1 wherein: A. upon transfer from the ITM, a temperature of the least partially dried ink-image is T.sub.Transfer; B. a dry film glass transition temperature T.sub.g.sup.dry_film([2.sup.nd component]) of the second ink component exceeds the transfer temperature T.sub.TRANSFER by at least 5° C.; and B. a dry film glass transition temperature T.sub.g.sup.dry_film([1.sup.st component]) of the first ink component is less than the transfer temperature T.sub.TRANSFER by at least 5° C.
10. The method of claim 1 wherein a ratio between A. upon transfer from the ITM, a temperature of the least partially dried ink-image is T.sub.Transfer; B. a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2.sup.nd component], T.sub.TRANSFER) of the second aqueous ink component at the transfer temperature T.sub.TRANSFER; and C. a dry ink film dynamic viscosity μ.sub.g.sup.dry_film ([5:1 2.sup.nd component: 1.sup.st component], T.sub.TRANSFER) of a 5:1 weight-ratio of the first and second components at the transfer temperature T.sub.TRANSFER is at least a positive number V, a value of V being at least 2.5.
11. The method of claim 1 wherein a ratio between A. upon transfer from the ITM, a temperature of the least partially dried ink-image is T.sub.Transfer; B. a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2.sup.nd component], T.sub.TRANSFER) of the second aqueous ink component at the transfer temperature T.sub.TRANSFER; and C. a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component], T.sub.TRANSFER) of the first aqueous ink component at the transfer temperature T.sub.TRANSFER is at least a positive number W, a value of W being 2 at least 3.
12. The method of claim 1, performed without forming a gel or gelatinous phase of the first aqueous ink component on the ITM surface.
13. The method of claim 1, wherein the provided first aqueous ink component (i) comprises between 40% wt/wt and 70% wt/wt water and (ii) further comprises at least 10% wt/wt binder.
14. The method of claim 1 wherein the provided first aqueous ink component is devoid of quaternary ammonium salts or comprises at most 0.25% quaternary ammonium salts, or their neutralized counterparts.
15. The method of claim 1, wherein the method is performed so that a ratio between (i) a thickness of a partially-dried layer of the first component when the droplets of the second aqueous ink component impact the partially-dried layer of the first ink component in step (d) and (ii) a thickness of the covering wet volume of the first component immediately upon application of the covering wet volume of the first component on the ITM surface is at most 0.5.
16. The method of claim 15, wherein the method is performed so that a ratio between (i) a thickness of a partially-dried layer of the first component when the droplets of the second aqueous ink component impact the partially-dried layer of the first ink component in step (d) and (ii) a thickness of the covering wet volume of the first component immediately upon application of the covering wet volume of the first component on the ITM surface is at least 0.25.
17. The method claim 1, wherein during step (d), the layer of the first component blocks the colorant particles of the second component from directly contacting the ITM surface so that, at a time of the transfer, a colorant-particle-free layer is present on the ITM surface below the colorant particles of the second component.
18. The method of claim 1, wherein during step (d) and while the layer of first component comprises at least 10% wt/wt water or at least 20% wt/wt water, the layer of the first component blocks the colorant particles of the second component from directly contacting the ITM surface so that, at a time of the transfer, a colorant-particle-free layer is present on the ITM surface below the colorant particles of the second component.
19. A system for indirect printing of a digital image on a printing substrate, the system comprising: a. a quantity of a first aqueous ink component; b. a quantity of a second aqueous ink component comprising colorant particles; c. an intermediate transfer member (ITM); b. a first print bar configured to deliver a quantity of the first ink component to a target surface of the ITM, to cover a portion of the target surface with a wet volume of the first ink component; d. a second print bar; e. a transport system for transporting material disposed on the ITM, the transport system configured to transport the wet volume, on the ITM, from the first to second print bars such that when the wet volume reaches the second print bar, the wet volume is only partially dried to produce a partially-dried layer of the first ink component on the ITM, wherein the second print bar is configured to digitally deposit droplets of the second ink component onto the partially-dried layer of the first component so as to form a wet, colored ink-image on the ITM, wherein the partially-dried layer of the first ink component is sufficiently moist and permeable such that at least 50% of the colorant particles of the second ink component penetrate into the partially-dried layer of the first ink component; and f. a transfer station disposed so that the transport system transports the web, colored ink-image so that it is at least partially tried upon reaching the transfer station, wherein the transfer station is configured to transfer the at least partially dried ink-image from the ITM to printing substrate.
20. The system of claim 19 wherein the first aqueous ink component is transparent.
21. The system of claim 19, configured such that at least 70% of the colorant particles of the second ink component penetrate into and mixed with the partially-dried layer of the first ink component.
22. The system of claim 19, configured such that at least 90% of the colorant particles of the second ink component penetrate into and mixed with the partially-dried layer of the first ink component.
23. The method of claim 1, wherein at least 90% of the colorant particles of the second ink component penetrate into and mixed with the partially-dried layer of the first ink component.
24. A method of printing a digital image on a printing substrate using an intermediate transfer member (ITM), the method comprising: a. providing: i. a first aqueous ink component; and ii. a second aqueous ink component comprising colorant particles; b. delivering a quantity of the first ink component to a target surface of the ITM, to cover a portion of the target surface with a wet volume of the first ink component; c. effecting only a partial drying of the wet volume to produce a partially-dried layer of the first ink component on the ITM; d. digitally depositing droplets of the second ink component onto the partially-dried layer of the first component so as to form a wet, colored ink-image on the ITM, wherein the partially-dried layer of the first ink component is sufficiently moist and permeable such that some or all the colorant particles of the second ink component penetrate into the partially-dried layer of the first ink component; e. at least partially drying the wet, colored ink-image; f. transferring the at least partially dried ink-image from the ITM to printing substrate, wherein the method is performed such that a ratio between (i) a thickness of a partially-dried layer of the first component when the droplets of the second aqueous ink component impact the partially-dried layer of the first ink component in step (d) and (ii) a thickness of the covering wet volume of the first component immediately upon application of the covering wet volume of the first component on the ITM surface is at least 0.25.
25. The method of claim 24 wherein the ratio is at least 0.5.
26. A system for indirect printing of a digital image on a printing substrate, the system comprising: a. a quantity of a first aqueous ink component; b. a quantity of a second aqueous ink component comprising colorant particles; c. an intermediate transfer member (ITM); b. a first print bar configured to deliver a quantity of the first ink component to a target surface of the ITM, to cover a portion of the target surface with a wet volume of the first ink component; d. a second print bar; e. a transport system for transporting material disposed on the ITM, the transport system configured to transport the wet volume, on the ITM, from the first to second print bars such that when the wet volume reaches the second print bar, the wet volume is only partially dried to produce a partially-dried layer of the first ink component on the ITM, wherein the second print bar is configured to digitally deposit droplets of the second ink component onto the partially-dried layer of the first component so as to form a wet, colored ink-image on the ITM, wherein the partially-dried layer of the first ink component is sufficiently moist and permeable such that some or all the colorant particles of the second ink component penetrate into the partially-dried layer of the first ink component; and f. a transfer station disposed so that the transport system transports the web, colored ink-image so that it is at least partially tried upon reaching the transfer station, wherein the transfer station is configured to transfer the at least partially dried ink-image from the ITM to printing substrate, wherein the system is configured such that a ratio between (i) a thickness of a partially-dried layer of the first component when the droplets of the second aqueous ink component impact the partially-dried layer of the first ink component in step (d) and (ii) a thickness of the covering wet volume of the first component immediately upon application of the covering wet volume of the first component on the ITM surface is at least 0.25.
27. The system of claim 26, configured such that the ratio is at least 0.5.
Description
BRIEF DESCRIPTION OF THE DRAWINGS
(1) Some embodiments of the printing system are described herein with reference to the accompanying drawings. The description, together with the figures, makes apparent to a person having ordinary skill in the art how the teachings of the disclosure may be practiced, by way of non-limiting examples. The figures are for the purpose of illustrative discussion and no attempt is made to show structural details of an embodiment in more detail than is necessary for a fundamental understanding of the disclosure. For the sake of clarity and simplicity, some objects depicted in the figures are not to scale.
(2) In the Figures:
(3)
(4)
(5)
(6)
(7)
(8)
(9)
(10)
(11)
(12)
(13)
(14)
DETAILED DESCRIPTION OF EMBODIMENTS
(15) The invention is herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. Throughout the drawings, like-referenced characters are generally used to designate like elements.
Definitions
(16) Within this application, the following terms should be understood to have the following meaning: a1) the term “receding contact angle” or “RCA”, refers to a receding contact angle as measured using a Data physics OCA15 Pro Contact Angle measuring device, or a comparable Video-Based Optical Contact Angle Measuring System, using the above-described Drop Shape Method, at ambient temperatures. The analogous “advancing contact angle”, or “ACA”, refers to an advancing contact angle measured substantially in the same fashion, using the method elaborated by Dr. Roger P. Woodward in the above-referenced “Contact Angle Measurements Using the Drop Shape Method”, at ambient temperatures, and as elaborated herein below in EXAMPLE 46. a2) the term “dynamic contact angle” or “DCA”, refers to a dynamic contact angle as measured using a Data physics OCA15 Pro Contact Angle measuring device, or a comparable Video-Based Optical Contact Angle Measuring System, using the method elaborated by Dr. Roger P. Woodward in the above-referenced “Contact Angle Measurements Using the Drop Shape Method”, at ambient temperatures, and as elaborated herein below in EXAMPLE 53. b) the term “standard aging procedure” refers to an accelerated aging protocol performed on each tested release layer at 160° C., for 2 hours, in a standard convection oven. c) the term “standard air curing” refers to a conventional curing process for curing the release layer, in which, during the curing of the release layer, the release layer surface (or “ink reception surface”) is exposed to air. d) the term “bulk hydrophobicity” is characterized by a receding contact angle of a droplet of distilled water disposed on an inner surface of the release layer, the inner surface formed by exposing an area of the cured silicone material within the release layer. e) the term “image transfer member” or “intermediate transfer member” or “transfer member” refers to the component of a printing system upon which the ink is initially applied by the printing heads, for instance by inkjet heads, and from which the jetted image is subsequently transferred to another substrate or substrates, typically, the final printing substrates. f) the term “blanket” refers to a flexible transfer member that can be mounted within a printing device to form a belt-like structure on two or more rollers, at least one of which is able to rotate and move the blanket (e.g. by moving the belt thereof) to travel around the rollers. g) the term “on the release surface” with respect to an object such as an ink image or ink residue, means supported by and/or over that release surface. The term “on the release surface” does not necessarily imply direct contact between the ink image or ink residue and the release surface. h) the term “has a static surface tension sufficiently high so as to increase said static surface tension of the aqueous treatment formulation”, and the like, with regard to a particular surfactant within that formulation, is evaluated by adding an additional quantities or aliquots of that particular surfactant to the formulation, and comparing the attained static surface tension of the formulation with the static surface tension of the formulation prior to the addition of those aliquots. i) the term “liquid hygroscopic agent” refers to a hygroscopic agent that is liquid at least one temperature within the range of 25° C.-90° C., and has, in a pure state and at 90° C., a vapor pressure of at most 0.05 ata, and more typically, at most 0.02 ata, at most 0.01 ata, or at most 0.003 ata. The term “liquid hygroscopic agent” is specifically meant to refer to materials like glycerol. j) the terms “hydrophobicity” and “hydrophilicity” and the like, may be used in a relative sense, and not necessarily in an absolute sense. k) the term ‘(treatment) formulation’ refers to either a solution or a dispersion. l) an x degrees' Celsius evaporation load is now defined, where x is a positive number. When a solution is y % solids wt/wt and z % liquid wt/wt at x degrees Celsius, the ‘x-degrees Celsius evaporation load’ of the solution is that ratio z/y. The units of ‘evaporation load’ are “weight solvent per weight total solute.’ For the present disclosure, evaporation load is always defined at atmospheric pressure. For the present disclosure, a default value of ‘x’ is 60 degrees C.—the term ‘evaporation load’ without a prefix specifying a temperature refers to a 60 degrees' Celsius evaporation load at atmospheric pressure. m) when a portion of an ITM is in motion at a speed of v meters/second, this means that the portion of the blanket ITM moves in a direction parallel to its local surface/plane at a speed of at least v meters/second—e.g. relative to an applicator which is stationary. n) the term ‘Static surface tension’ refers to the static surface tension at 25° C. and atmospheric pressure. o) the term ‘thickness’ of a wet layer may be determined as follows: when a volume of material (herein “vol”) covers a surface area of a surface having an area SA with a wet layer—the thickness of the wet layer is assumed to be vol/SA. p) the term ‘thickness’ of a dry film is defined as follows. When a volume of material vol that is x % liquid, by weight, wets or covers a surface area SA of a surface, and all the liquid is evaporated away to convert the wet layer into a dry film, a thickness of the dry film is assumed to be:
Vol/ρ.sub.wet layer(100−x)/(SA.Math.ρ.sub.dry layer)
where ρ.sub.wet layer is the specific gravity of the wet layer and ρ.sub.dry layer is the specific gravity of the dry layer. q) the term ‘cohesive film’ refers to a construct which stays together when peeled away from a surface to which it is adhered—i.e. when peeled away from the surface, the ‘cohesive film’ retains it structural integrity and is peeled as a skin, rather than breaking into little pieces. r) unless stated otherwise, physical properties of a liquid (e.g. treatment formulation) such as viscosity and surface tension, refer to the properties at 25° C. s) unless stated otherwise, a ‘concentration’ refers to a wt/wt—i.e. a weight of a component of formulation per total weight of that formulation. t) the term “functional group” refers to a group or moiety attached to the polymer structure of the release layer, and having a higher polarity than the O—Si—O group of conventional addition-cured silicones. Various examples are provided herein. The inventors observe that pure addition cure poly-dimethyl siloxane polymer contains O—Si—O, SiO.sub.4, Si—CH.sub.3 and C—C groups, and that most other functional groups will have a higher dipole, such that they may be considered “functional”. It will be appreciated by those of skill in the art that such functional groups, may have a tendency or strong tendency to react with components typically present in aqueous inks utilized in indirect inkjet printing, at process temperatures of up to 120° C. u) the term “transparent”, with respect to an ink component such as the first aqueous ink component, refers to at least one of: (i) an opacity of at most 4%, and more typically, at most 3%, at most 2.5%, at most 2%, at most 1.5%, or at most 1.2%, as elaborated in EXAMPLE 8 herein below; (ii) having a colorant (e.g. pigment) content of at most 0.2%, at most 0.1%, at most 0.05%, or at most 0.02%, or being substantially devoid of such colorant; (iii) being transparent, as measured or characterized by those of skill in the art of printing; and (iv) being transparent, as understood by those of skill in the art of printing. v) the term “resoluble”, “re-solubility”, and the like, with respect to an ink component such as the second aqueous ink component, refers to a feature as determined by the Re-solubility Characterization procedure provided below in EXAMPLE 25. w) the term “transfer temperature”, and the like, refers to the temperature as measured by an IR thermometer pointed at the release surface of the blanket, at the nip area. x) the term “5:1 weight ratio of the 1.sup.st and 2.sup.nd ink components”, and the like, with respect to one or more dry ink films, refers to the weight of the dry film of the 1.sup.st ink component divided by the weight of the dry film of the 2.sup.nd ink component.
A Discussion of
(17)
(18)
(19) In particular, steps S201-S205 relate to the ingredients or components or consumables used in the printing process of
(20) Briefly, the steps of
(21) In step S209, a quantity of the first ink component is delivered to a target surface of the ITM, to cover a portion of said target surface with a wet volume of said first ink component. For example, droplets of the first ink component may be deposited (e.g. by ink-jetting) onto the ITM target surface such the covered ‘portion’ of the target surface may be dis-contiguous. However, this is not a requirement, and in other examples, a relatively large contiguous region (e.g. at least 1 cm by 1 cm) may be covered in step S209.
(22) In step S211, the wet volume of the first ink component is subjected only to a partial drying, to produce a partially-dried layer of the first component on the ITM.
(23) In step S213, droplets of the second (e.g. comprising colorant such as pigment particles and/or a dye) ink component are deposited (e.g. digitally deposited) onto the partially-dried layer of the first component (i.e. which is produced in step S211) so as to form a wet, colored ink-image on the ITM. For example, the deposited droplets contact the partially-dried layer of the first component at a time when the partially-dried layer of the first component is sufficiently moist and permeable such that some or all (e.g. at least 10% of, or at least 30% of, or at least a majority of) the colorant particles of the second ink aqueous component penetrate into (i.e. penetrate beneath an upper surface thereof) the partially-dried layer of the first component.
(24) In step S217, the wet, colored ink-image (i.e. which is formed in step S213) is at least partially dried. For example, at least partial trying of step S217 is performed at least in part by heating the ink-image. Alternatively or additionally, concurrently or after the at least partial drying the ink-image is heated on the ITM before the subsequent transfer of step S221. For example, the heating (e.g. performed in step S217 or subsequent thereto but before step S221) may serves to evaporate solvent. For example, the heating (e.g. performed in step S217 or subsequent thereto but before step S221) may be sufficient render the ink image tacky and/or produce a dried, tacky ink-image-bearing residue film. An “ink-image-bearing residue film” is a residue film that contains an ink image.
(25) In step S221, the at least partially dried ink-image is transferred from the ITM to printing substrate. For example, in embodiments where a tacky ink-image-bearing residue-film is produced in step S217 or subsequently thereto, this tacky ink-image-bearing residue-film may be transferred (i.e. in step S221) from the ITM (e.g. a transfer surface thereof) to substrate. For example, during step S221 the tacky ink-image-bearing residue-film is at a ‘transfer temperature’ T.sub.TRANSFER that is, e.g. at most 115° C., at most 110° C., at most 105° C., at most 100° C., at most 95° C., at most 90° C., at most 85° C., at most 80° C., at most 75° C., at most 70° C. In embodiments of the invention, step S221 is performed by pressured contact between the ITM surface and the substrate—e.g. pressured contact in a nip region between two opposing cylinders where the ink-image-bearing residue film is disposed during transfer).
(26) Generally speaking, the order of steps in
(27) A Discussion of Step S201
(28) In some embodiments, the first ink aqueous ink component of step S201 may provide (i.e. in pure form) one of more (i.e. any combination of) of the following features A1-A24: A1. Min wt/wt water carrier liquid—In some embodiments, the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) first aqueous ink component treatment formulation comprises at least 35% wt/wt water or at least 40% wt/wt water or at least 50% wt/wt water or at least 55% wt/wt water. A2. Max wt/wt water carrier liquid—The provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) first aqueous ink component comprises at most 75% wt/wt water or at most 70% wt/wt water or at most 65% wt/wt water. A3. wt/wt water carrier liquid (specific ranges)—The provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) first aqueous ink component comprises between 35% wt/wt and 75% wt/wt water or between 40% wt/wt and 75% wt/wt water or between 40% wt/wt and 70% wt/wt water or between 50% wt/wt and 70% wt/wt water. A4. Evaporation load—In some embodiments, the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) first aqueous ink component has a 60° C. evaporation load that may be at most 10:1, at most 9:1, at most 8:1, at most 7:1, at most 6:1, at most 5:1, at most 4:1, at most 3.5:1, or at most 3:1. Alternatively or additionally, the 60° C. evaporation load may be at least 2:1, at least 2.2:1, or at least 2.5:1. In some embodiments, the evaporation load is between 2:1 and 10:1. In some embodiments, the evaporation load is between 2:1 and 8:1. In some embodiments, the evaporation load is between 2.5:1 and 7:1. In some embodiments, the evaporation load is between 2.5:1 and 5:1. In some embodiments, the evaporation load is between 2.5:1 and 4:1. In some embodiments, the evaporation load is between 2.5:1 and 3.5:1. In some embodiments, the evaporation load is between 2.8:1 and 4:1. In some embodiments, the evaporation load is between 2.8:1 and 3.5:1.
(29) Not wishing to be bound by theory, in some embodiments, having an evaporation load with a relatively ‘low’ upper bound may be useful for (i) increasing a rate at which a viscosity of the first component increases (e.g. in step S211—for example, so as to reduce and/or counteract a tendency of the first component to bead on the ITM surface) and/or (ii) increasing a rate at which the viscosity of the mixture of the first and second components increases (e.g. in step S217—for example, to prevent colorant particles from traversing an entirety of a layer of the first component (“bleeding through” to reach the ITM surface) to contact the ITM surface or release layer. This, may, for example, obviate the need for including or relying on a presence, in the first ink component, of chelating agents or other agents that rapidly fix the solids to the target surface. A5. Comprising one or more binders (at a minimum and/or maximum wt %)—In some embodiments, the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) first aqueous first ink component formulation comprises (i.e. as a wt % of the first ink component including the aqueous liquid carrier of the first aqueous ink component) at least 6% wt/wt or at least 7% or at least 8% or at least 9% or at least 10% or at least 11% or at least 12%.
(30) Binder may be useful for rendering a residue-film tacky (e.g. at a relatively ‘low temperature” and/or for playing a role in maintaining cohesively of the residue-film upon transfer. As will be discussed below, in embodiments of the invention: (i) a binder fraction of the second component is lower than the binder fraction of the first ink component and (ii) during step S213-S217) binder droplets of the second component may mix with and become subsumed within (e.g. to form) a single unified film layer.
(31) Binders play an important role in the transferability of the dried 1.sup.st ink component, and the dried ink image containing both ink components, from the release layer of the ITM. Binders also play an important role in the adhesion of the dried ink image to the printing substrate.
(32) Examples of binders include polystyrene-acrylate co-polymers, poly-acrylate polymers, polyurethanes (e.g., aliphatic polyurethanes such as anionic aliphatic polyurethanes), urethane-acrylate co-polymers, and polyesters (e.g., a polyethylene terephthalate).
(33) Exemplary styrene-acrylic (or polystyrene-acrylate) copolymers include Joncryl® 77E, Joncryl® 586, Joncryl® 90, Joncryl® 8085, and Joncryl® ECO 2177.
(34) An exemplary polyurethane includes NeoRez® R-563, an anionic aliphatic polyurethane from DSM-PUD.
(35) Exemplary acrylic or polyacrylic binders include Joncryl® 538, an acrylic polymer emulsion.
(36) Exemplary polyesters include Plascoat Z-105, Plascoat Z-730, and Plascoat Z-750, (all from GOO Chemicals).
(37) The binders may be provided in various forms, such as dispersions or emulsions, with for example water typically being the major carrier liquid.
(38) In different embodiments, the presence of the binder may be useful for rending a residue film tacky at a particular transfer temperature T.sub.TRANSFER and/or providing cohesiveness upon transfer. A6. Having a surfactant concentration in a specific range—In some embodiments, the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) first aqueous ink component comprises at most 5% wt/wt or at most 4% wt/wt surfactants. A7. Moderately hydrophilic initial aqueous treatment formulation—In some embodiments, the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) first aqueous ink component) is only moderately hydrophilic—e.g. having a static surface tension at 25° C. of at most 32 dynes/cm (e.g. between 20 and 32 dynes/cm) or at most 30 dynes/cm (e.g. between 20 and 32 dynes/cm) or at most 28 dynes/cm (e.g. between 20 and 32 dynes/cm). Because the release surface of the ITM has moderately hydrophobic (or moderately hydrophilic) properties, it may not be useful to employ a first ink component having high hydrophilicity, which may increase a thermodynamic tendency towards beading during step S209. A8. Devoid of quaternary ammonium salts or having at most a low concentration thereof—In some embodiments, the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) first aqueous ink component is devoid of quaternary ammonium salts or comprises at most 1% wt/wt or at most 0.75% wt/wt or at most 0.5% wt/wt or at most 0.25% quaternary ammonium salts, or their neutralized counterparts. A9. Having a viscosity in a specific range—In some embodiments, a dynamic viscosity of the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) first aqueous ink component is at most 100 mPa.Math.s (millipascal seconds) or at most 80 mPa.Math.s. A10. Having a viscosity in a specific range—In embodiments where the first ink component is delivered by droplet-deposition in step S209 (e.g. by ink-jetting), the first aqueous ink component lower viscosity may have a value of at most 35 mPa.Math.s, at most 30 mPa.Math.s, at most 25 mPa.Math.s, at most 20 mPa.Math.s, or at most 15 mPa.Math.s. A11. Having a viscosity in a specific range—In some embodiments, the viscosity of the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) first aqueous ink component is at least 3 mPa.Math.s, at least 4 mPa.Math.s, at least 5 mPa.Math.s, or at least 6 mPa.Math.s. A12. Devoid of (or having at most a low concentration of) organic solvents such as glycerol—In some embodiments, a presence of low vapor pressure organic solvents might retard the drying of the first ink component on the surface of the ITM and/or result in a treatment film lacking desired elasticity and/or cohesiveness or tensile strength desired for the transfer step. In some embodiments, the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) first aqueous ink component may be devoid of organic solvents (irrespective of their vapor pressure) in the pure state and/or comprises at most 3%, at most 2%, at most 1%, or at most 0.5%, or at most 0.25% or at most 0.1% by weight, organic solvents. In some embodiments, the formulation is devoid of organic solvents and/or comprises at most 3%, at most 2%, at most 1%, or at most 0.5%, or at most 0.25% or at most 0.1% by weight, glycerol. In some embodiments, the formulation is completely devoid of glycerol. A13. Devoid of (or having at most a low concentration of) chelating agents—In some embodiments, the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) first aqueous ink component may be devoid of chelating agents and/or comprises at most 3%, at most 2%, at most 1%, or at most 0.5%, or at most 0.25% or at most 0.1% by weight, chelating agents. A14. Devoid of (or having at most a low concentration of) water soluble film-forming polymers such as polyvinyl alcohol (PVA) or polyvinyl pyrrolidone (PVP)—In some embodiments, the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) first aqueous ink component may be devoid of water soluble film-forming polymers such as polyvinyl alcohol (PVA) or polyvinyl pyrrolidone (PVP) and/or comprises at most 3%, at most 2%, at most 1%, or at most 0.5%, and more typically at most 0.25% or at most 0.1% by weight, water soluble film-forming polymers. A15. Dry film glass transition temperature T.sub.g.sup.dry_film([1.sup.st component])—In some embodiments, a dry film glass transition temperature T.sub.g.sup.dry_film([1.sup.st component]) of the first ink component (i.e. as a pure component) is at most 115° C., or at most 110° C., at most 105° C., or at most 100° C., or at most 95° C., at most 90° C., at most 85° C., at most 80° C., at most 70° C., at most 65° C., at most 60° C., or at most 55° C. This reference is to the dry film glass transition temperature T.sub.g.sup.dry_film([1.sup.st component]) of the first ink component as a pure component. A16. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component] at 115° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film ([1.sup.st component], 115° C.) is at most 1*10.sup.7 mPa.Math.s or at most 8*10.sup.6 mPa.Math.s or at most 6*10.sup.6 mPa.Math.s or at most 4*10.sup.6 mPa.Math.s. A17. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component] at 110° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component], 110° C.) is at most 1*10.sup.7 mPa.Math.s, or at most 8*10.sup.6 mPa.Math.s, or at most 6*10.sup.6 mPa.Math.s or at most 5*10.sup.6 mPa.Math.s or at most 4*10.sup.6 mPa.Math.s. A18. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component] at 105° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component], 105° C.) is at most 2*10.sup.7 mPa.Math.s, at most 1*10.sup.7 mPa.Math.s, or at most 8*10.sup.6 mPa.Math.s, or at most 6*10.sup.6 mPa.Math.s. A19. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component] at 100° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component], 100° C.) is at most 2*10.sup.7 mPa.Math.s, at most 1*10.sup.7 mPa.Math.s, or at most 8*10.sup.6 mPa.Math.s, or at most 6*10.sup.6 mPa.Math.s. A20. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component] at 95° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component], 95° C.) is at most 4*10.sup.7 mPa.Math.s, at most 2*10.sup.7 mPa.Math.s, at most 1*10.sup.7 mPa.Math.s, at most 8*10.sup.6 mPa.Math.s, or at most 6*10.sup.6 mPa.Math.s. A21. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component] at 90° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component], 90° C.) is at most 2*10.sup.7 mPa.Math.s or at most 1.2*10.sup.7 mPa.Math.s, or more typically, at most 1*10.sup.7 mPa.Math.s, at most 8*10.sup.6 mPa.Math.s, or at most 6*10.sup.6 mPa.Math.s. A22. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component] at 80° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component], 80° C.) is at most 2.5*10.sup.7 mPa.Math.s or at most 1.2*10.sup.7 mPa.Math.s, or more typically, at most 1*10.sup.7 mPa.Math.s, at most 8*10.sup.6 mPa.Math.s, or at most 8*10.sup.6 mPa.Math.s. A23. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component] at 70° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component], 70° C.) is at most 6*10.sup.7 mPa.Math.s, at most 3*10.sup.7 mPa.Math.s, or at most 1.2*10.sup.7 mPa.Math.s, or more typically, at most 1*10.sup.7 mPa.Math.s, at most 8*10.sup.6 mPa.Math.s, or at most 8*10.sup.6 mPa.Math.s. A24. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component] at 65° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component], 65° C.) is at most 1*10.sup.8 mPa.Math.s, at most 5*10.sup.7 mPa.Math.s, or at most 2*10.sup.7 mPa.Math.s, or more typically, at most 1*10.sup.7 mPa.Math.s, at most 8*10.sup.6 mPa.Math.s, or at most 8*10.sup.6 mPa.Math.s. A25. Devoid of starch—In some embodiments, the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) first aqueous ink component may be devoid of starch and/or comprises at most 3%, at most 2%, at most 1%, or at most 0.5%, and more typically at most 0.25% or at most 0.1% by weight, starch.
A Discussion of Step S203
(39) In some embodiments, the second ink aqueous ink component of step S203 may provide (i.e. in pure form) one of more (i.e. any combination of) of the following features B1-B18: B1. Min wt/wt water carrier liquid—In some embodiments, the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) second aqueous ink component treatment formulation comprises at least 40% wt/wt water or at least 45% wt/wt water or at least 50% wt/wt water or at least 55% wt/wt water or at least 60% wt/wt water or at least 65% wt/wt water. B2. Percent solids (lower bound)—In some embodiments, the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) second aqueous ink component treatment formulation comprises at least 6% wt/wt solids, or at least 7% wt/wt solids, or at least 8% wt/wt solids, where the terms ‘solids’ refers to material that is solid at 60° C. B3. Percent solids (upper bound)—In some embodiments, the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) second aqueous ink component treatment formulation comprises at most 15% wt/wt solids, or at most 14% wt/wt solids, or at most 13% wt/wt solids, or at most 12% wt/wt solid, where the terms ‘solids’ refers to material that is solid at 60° C. B4. Percent solids (specific range)—In some embodiments, the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) second aqueous ink component treatment formulation comprises between 7% wt/wt and 13% wt/wt solids. B5. Binder Weight fraction (upper bound)—In some embodiments, the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) second aqueous ink component formulation comprises (i.e. as a wt % of the second ink component including the aqueous liquid carrier of the second aqueous ink component) at most 3% wt/wt or at most 2.5% wt/wt or at most 2% wt/wt or at most 1.5% wt/wt or at most 1% wt/wt or at most 0.5% wt/wt binder. B6. Binder: Pigment ratio—In some embodiments, within the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) second aqueous ink component formulation, a ratio between (i) a weight fraction of binder within the second aqueous ink component formulation; and (ii) a weight fraction of pigment within the second aqueous ink component formulation is at most 1.5:1 or at most 1.3:1 or at most 1.2:1 or at most 1.1:1 or at most 0.8:1, or at most 0.6:1, or at most 0.4:1. B7. Re-solubility—In some embodiments, the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) second aqueous ink component is a resoluble ink component. B8. Nanoparticles—In some embodiments, the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) second aqueous ink component comprises nanoparticles—e.g. a primary colorant of the second aqueous ink component is nanoparticles. B9. Dry film glass transition temperature T.sub.g.sup.dry_film([2nd component])—In some embodiments, a dry film glass transition temperature T.sub.g.sup.dry_film([2nd component]) of the second ink component (i.e. as a pure component) is at least 90° C., or at least 95° C., or at least 100° C., at least 105° C., or at least 110° C., or at least 115° C. This reference to the dry film glass transition temperature T.sub.g.sup.dry_film ([2nd component]) of the second ink component as a pure component. B10. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2nd component] at 115° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2nd component], 115° C.) is at least 8*10.sup.6 mPa.Math.s, at least 1*10.sup.7 mPa.Math.s, at least 3*10.sup.7 mPa.Math.s, or at least 6*10.sup.7 mPa.Math.s. B11. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2nd component] at 110° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2nd component], 110° C.) is at least 1*10.sup.7 mPa.Math.s, at least 3*10.sup.7 mPa.Math.s, at least 5*10.sup.7 mPa.Math.s, or at least 8*10.sup.7 mPa.Math.s. B12. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2nd component] at 105° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2nd component], 105° C.) is at least at least 1.2*10.sup.7 mPa.Math.s, at least 3*10.sup.7 mPa.Math.s, at least 5*10.sup.7 mPa.Math.s, or at least 1*10.sup.8 mPa.Math.s. B13. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2nd component] at 100° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2nd component], 100° C.) is at least 1.5*10.sup.7 mPa.Math.s, at least 3*10.sup.7 mPa.Math.s, at least 7*10.sup.7 mPa.Math.s, or at least 2*10.sup.8 mPa.Math.s. B14. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2nd component] at 95° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2nd component], 95° C.) is at least is at least 2*10.sup.7 mPa.Math.s, at least 5*10.sup.7 mPa.Math.s, at least 1*10.sup.8 mPa.Math.s, or at least 3*10.sup.8 mPa.Math.s. B15. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2nd component] at 90° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2nd component], 90° C.) is at least 2*10.sup.7 mPa.Math.s, at least 4*10.sup.7 mPa.Math.s, at least 6*10.sup.7 mPa.Math.s, at least 8*10.sup.7 mPa.Math.s, at least 1*10.sup.8 mPa.Math.s, at least 3*10.sup.8 mPa, or at least 5*10.sup.8 mPa. B16. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2nd component] at 80° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2nd component], 80° C.) is at least 3*10.sup.7 mPa.Math.s, at least 6*10.sup.7 mPa.Math.s, at least 8*10.sup.7 mPa.Math.s, at least 2*10.sup.8 mPa.Math.s, or at least 7*10.sup.8 mPa.Math.s. B17. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2nd component] at 70° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2nd component], 70° C.) is at least 3*10.sup.7 mPa.Math.s, at least 6*10.sup.7 mPa.Math.s, at least 8*10.sup.7 mPa.Math.s, at least 2*10.sup.8 mPa.Math.s, at least 5*10.sup.8 mPa.Math.s, or at least 9*10.sup.8 mPa.Math.s. B18. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2nd component] at 60° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2nd component], 60° C.) is at least 3*10.sup.7 mPa.Math.s, at least 6*10.sup.7 mPa.Math.s, at least 8*10.sup.7 mPa.Math.s, at least 2*10.sup.8 mPa.Math.s, at least 5*10.sup.8 mPa.Math.s, or at least 9*10.sup.8 mPa.Math.s.
A First Discussion of Steps S201 and S203 (‘Combo Features’ Depending on Properties of Both the First and Second Ink Components)
(40) In some embodiments, the first and second ink aqueous ink components respectively of steps S201 and S203 may provide (i.e. in respective pure forms) one or more (i.e. any combination of) of the following features C1-C4: C1. Binder weight fraction ratio (upper bound)—In some embodiments, the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) first and second aqueous ink component formulation collectively provide the following property—a ratio between (i) a weight fraction of binder in the first component and (ii) a weight fraction of binder in the second component is at least 1.5, or at least 1.75:1, or at least 2:1, or at least 2.25:1, or at least 2.25:1, or at least 3:1, or at least 4:1 or at least 5:1, or at least 6:1 or at least 7:1, or at least 8:1, or at least 9:1, or at least 10:1. This ratio may be infinite, as the 2.sup.nd ink component may be devoid of binder. C2. Percent Solids Ratio—In some embodiments, the provided (i.e. before delivery to the ITM—e.g. as stored in a reservoir) first and second aqueous ink component formulation collectively provide the following property—a ratio between (i) a weight fraction of solids in the first component and (ii) a weight fraction of solids in the second component is at least 1.8, at least 2.0, at least 2.2, at least 2.5, or at least 3.0, where the term ‘solids’ refers to material that is solid at 60° C. C3. Difference in Dry film glass transition temperatures between T.sub.g.sup.dry_film([2nd component) and T.sub.g.sup.dry_film([1 wt component])—In some embodiments, a difference T.sub.g.sup.dry_film([2nd component)−T.sub.g.sup.dry_film([1 wt component]) is at least 0° C., or at least 1° C., or at least 2° C., or at least 3° C., or at least 4° C., or at least 5° C., or at least 6° C., or at least 7° C., or at least 8° C., or at least 9° C., or at least 10° C., or at least 12° C., or at least 15° C. C4. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2nd component] at 115° C.—In some embodiments, a ratio between (i) μ.sub.g.sup.dry_film([2nd component], 115° C.) and (ii) T.sub.g.sup.dry_film([2nd component], 115° C.) is at least 3:1, at least 4:1, at least 5:1, at least 7:1, at least 10:1, at least 15:1, or at least 25:1, and/or within a range of 3:1 to 25:1, 3:1 to 10:1, 3:1 to 7:1, 5:1 to 25:1, 5:1 to 15:1, 5:1 to 10:1, 5:1 to 7:1, 7:1 to 25:1, 7:1 to 15:1, or 7:1 to 10:1.
A Second Discussion of Steps S201 and S203 (‘Combo Features’ Depending on Properties of Both the First and Second Ink Components)
(41) In some embodiments, the first and second ink aqueous ink components respectively of steps S201 and S203 may provide (i.e. in respective pure forms) one of more (i.e. any combination of) of the following features D1-D10, each of which is descriptive of a 5:1 weight ratio mixture of the first and second components: D1. Dry film glass transition temperature T.sub.g.sup.dry_film([5:1 2.sup.nd component:1.sup.st component]) (upper bound)—In some embodiments, a dry film glass transition temperature T.sub.g.sup.dry_film([5:1 2.sup.nd component:1.sup.st component]) of a 5:1 weight-ratio of the first and second components is less than 115° C., or less than 110° C., or less than 105° C., or less than 100° C., or less than 95° C., or less than 90° C., or less than 85° C., or less than 80° C., or less than 70° C., or less than 65° C., or less than 60° C., or less than 55° C. D2. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component] at 115° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([5:1 2.sup.nd component:1.sup.st component], 115° C.) of a 5:1 weight-ratio of the first and second components is at most 1*10.sup.7 mPa.Math.s, or at most 8*10.sup.6 mPa.Math.s, at most 6*10.sup.6 mPa.Math.s, or at most 4*10.sup.6 mPa.Math.s. D3. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component] at 110° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([5:1 2.sup.nd component:1.sup.st component], 110° C.) of a 5:1 weight-ratio of the first and second components is at most 1*10.sup.7 mPa.Math.s, or at most 8*10.sup.6 mPa.Math.s, or more typically, at most 6*10.sup.6 mPa.Math.s or at most 5*10.sup.6 mPa.Math.s or at most 4*10.sup.6 mPa.Math.s. D4. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component] at 105° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([5:1 2.sup.nd component:1.sup.st component], 105° C.) of a 5:1 weight-ratio of the first and second components is at most 2*10.sup.7 mPa.Math.s, at most 1*10.sup.7 mPa.Math.s, at most 8*10.sup.6 mPa.Math.s, or at most 6*10.sup.6 mPa.Math.s. D5. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component] at 100° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([5:1 2.sup.nd component:1.sup.st component], 100° C.) of a 5:1 weight-ratio of the first and second components) is at most 2*10.sup.7 mPa.Math.s, at most 1*10.sup.7 mPa.Math.s, at most 8*10.sup.6 mPa.Math.s, or at most 6*10.sup.6 mPa.Math.s. D6. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component] at 95° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([5:1 2.sup.nd component:1.sup.st component], 95° C.) of a 5:1 weight-ratio of the first and second is at most 4*10.sup.7 mPa.Math.s, at most 2*10.sup.7 mPa.Math.s, at most 1*10.sup.7 mPa.Math.s, at most 8*10.sup.6 mPa.Math.s, or at most 6*10.sup.6 mPa.Math.s. D7. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component] at 90° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([5:1 2.sup.nd component:1.sup.st component], 90° C.) of a 5:1 weight-ratio of the first and second components is at most 2*10.sup.7 mPa.Math.s or at most 1.2*10.sup.7 mPa.Math.s, or more typically, at most 1*10.sup.7 mPa.Math.s, at most 8*10.sup.6 mPa.Math.s, or at most 6*10.sup.6 mPa.Math.s. D8. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component] at 80° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([5:1 2.sup.nd component:1.sup.st component], 80° C.) of a 5:1 weight-ratio of the first and second components is at most 2.5*10.sup.7 mPa.Math.s or at most 1.2*10.sup.7 mPa.Math.s, or more typically, at most 1*10.sup.7 mPa.Math.s, at most 8*10.sup.6 mPa.Math.s, or at most 8*10.sup.6 mPa.Math.s. D9. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component] at 70° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([5:1 2.sup.nd component:1.sup.st component], 70° C.) of a 5:1 weight-ratio of the first and second components is at most 6*10.sup.7 mPa.Math.s, at most 3*10.sup.7 mPa.Math.s, or at most 1.2*10.sup.7 mPa.Math.s, or more typically, at most 1*10.sup.7 mPa.Math.s, at most 8*10.sup.6 mPa.Math.s, or at most 8*10.sup.6 mPa.Math.s. D10. A dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component] at 65° C.—In some embodiments, a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([5:1 2.sup.nd component:1.sup.st component], 65° C.) of a 5:1 weight-ratio of the first and second components is at most 1*10.sup.8 mPa.Math.s, at most 5*10.sup.7 mPa.Math.s, or at most 2*10.sup.7 mPa.Math.s, or more typically, at most 1*10.sup.7 mPa.Math.s, at most 8*10.sup.6 mPa.Math.s, or at most 8*10.sup.6 mPa.Math.s.
A Discussion of Step S205 of
(42) In some embodiments, the ITM provided in step S205 has a silicone based release layer, the release surface thereof may be less hydrophobic or appreciably less hydrophobic than many conventional silicone-based release layers. This structural property can be measured and characterized in various ways.
(43) For example, as illustrated in step S205 of
(44) Any one of several techniques for reducing the hydrophobicity of the silicone based release layer may be employed.
(45) In some embodiments, polar functional groups are introduced into and/or generated in the silicone based release layer. In one example, functional groups may be added to the pre-polymeric batch (e.g. monomers in solution)—these functional groups may, upon curing, become integral part of the silicone polymer network. Alternatively, or additionally, the silicone-based release layer is pre-treated (e.g. by a corona discharge, or by an electron beam), thereby increasing a surface energy thereof.
(46) Alternatively, the silicone based release layer may be manufactured to have a reduced hydrophobicity, even when substantially devoid of functional groups. In one example, the silicone polymer backbone of the release layer may be structured so that the polar groups thereof (e.g., O—Si—O) are oriented in a direction that is generally normal to the local plane of the ITM surface and facing ‘upwards’ towards the release layer surface.
(47) In different embodiments, the ITM may provide one of more (i.e. any combination of) of the following features E1-E5: E1: Release layer—In some embodiments, the release layer is formed of a silicone material (e.g. addition-cured)—this provides the ITM with hydrophobic properties useful in step S117; E2: Release layer with reduced hydrophobicity—The silicone-based release layer has been produced in a manner that reduces a hydrophobicity thereof. For example, instead of relying on the addition of functional, reactive groups to imbue the release layer with hydrophilicity, it is possible to cure the silicone release layer so that polar atoms in polar groups (e.g. the oxygen atom in a polar Si—O—Si moiety) are aligned or otherwise face outwardly with respect to the release layer surface. In this example, the oxygen atom of the “Si—O—Si” is not capable, under typical process conditions, of chemically bonding to the materials within the treatment solution, to the dried ink image and/or to the dried treatment film. However, it is possible to benefit from the hydrophilicity of the outwardly-facing, polar “O”. E3: Release layer with moderately hydrophobicity—The release surface of the ITM may have moderately hydrophobic properties but is not overly hydrophobic. Thus, the release surface may have a surface energy (at 25° C.) of at least 20 dynes/cm or at least 21 dynes/cm or at least 22 dynes/cm or at least 23 dynes/cm, or at least 25 dynes/cm, at least 28 dynes/cm, at least 30 dynes/cm, at least 32 dynes/cm, at least 34 dynes/cm, or at least 36 dynes/cm, and/or at most 48 dynes/cm, at most 46 dynes/cm, at most 44 dynes/cm, at most 42 dynes/cm, at most 40 dynes/cm, at most 38 dynes/cm, or at most 37 dynes/cm or most 35 dynes/cm. E4: Receding contact angle of a droplet of distilled water on release layer surface—A receding contact angle of a droplet of distilled water on the ink reception or release layer surface is typically at least 30°, and more typically, 30° to 80°, 35° to 80°, 30° to 75°, 35° to 75°, 30° to 65°, 30° to 55°, or 35° to 55°. E5: Devoid of functional groups bonded within the cross-linked polymer structure—The release layer of the ITM may be devoid or substantially devoid of functional groups bonded within the cross-linked polymer structure; the inventors believe that such functional groups may increase or promote an undesired adhesion.
A Discussion of Step S209
(48) In some embodiments, step S209 is performed to provide one or more (i.e. any combination of) following features F1-F4: F1—a thickness of the covering wet volume of the first component (i e immediately upon formation on/application to/delivery to) the ITM surface is at least 6 μm or at least 8 μm or at least 10 μm or at least 12 μm). F2—the first ink component is delivered to the ITM surface by droplet deposition (e.g. by ink-jetting). F3—the first ink component is delivered to the ITM surface by droplet deposition (e.g. by ink-jetting) according to a pattern of the ink-image to be formed in step S213 (e.g. centers of the droplets of the first ink component upon impact correspond to centers of the ink-image later formed in step S213). F4—the first ink component is delivered to the ITM surface when the ITM surface is in-motion at a velocity of at least 1 meters/second or at least 1.5 meters/second or at least 2 meters/second, to form the wet treatment layer thereon.
A Discussion of Step S211
(49) In some embodiments, step S211 is performed to provide one of more (i.e. any combination of) following features G1-G2: G1—a ratio between (i) a thickness of a partially-dried layer of the first component when the droplets of the second aqueous ink component impact the partially-dried layer of the first ink component in step S213 and (ii) a thickness of the covering wet volume of the first component (i.e. immediately upon formation on/application to/delivery to) the ITM surface in step S209 is at most 0.6 or at most 0.5 or at most 0.4. G2—a ratio between (i) a thickness of a partially-dried layer of the first component when the droplets of the second aqueous ink component impact the partially-dried layer of the first ink component in step S213 and (ii) a thickness of the covering wet volume of the first component (i.e. immediately upon formation on/application to/delivery to) the ITM surface in step S209 is at least 0.25 or at least 0.3 or at least 0.35.
A Discussion of Step S213
(50) In some embodiments, step S213 is performed to provide one of more (i.e. any combination of) following features H1-H5: H1—the second component is delivered by ink-jetting. H2—within the ink-jet nozzles during ink-jetting of the second component and under jetting conditions (e.g. temperature) embodiments, the second aqueous ink component is a resoluble ink component. Thus, in some embodiments, the depositing of the droplets of the second aqueous ink component is performed under a set of conditions where the second ink-component is fully resoluble. Not wishing to be bound by theory, this may be attributable, at least in part, to the relatively low binder fraction of the second aqueous ink component provided in step S203. H3—immediately before impact between the droplets of the second ink component and the layer of the first ink component, a liquid content of the layer of the first ink component is at least 10% wt/wt or at least 20% wt/wt or at least 30% wt/wt or at least 40% wt/wt. H4—immediately before impact between the droplets of the second ink component and the layer of the first ink component, a thickness of the layer of first ink component is at least 1 mm or at least 1.5 μm or at least 2 μm or at least 3 μm or at least 4 μm. H5—upon impact between the droplets of the second ink component and the layer of the first ink component, some or all the colorant particles of the second ink component penetrate into the partially-dried layer of the first ink component. In one example, for a given deposited droplet of second component, at least 10% or at least 20% or at least 30% or at least 50% or at least 70% or at least 80% or at least 90% of the colorant particles may component penetrate into and mixed with the partially-dried layer of the first ink component.
A Discussion of Step S221
(51) In some embodiments, step S221 is performed to one of more of the following features: I1—the transfer temperature T.sub.TRANSFER is at least 60° C., at least 65° C., at least 70° C., at least 75° C., at least 80° C., at least 85° C., at least 90° C., at least 95° C., at least 100° C., at least 105° C., at least 110° C., or at least 115° C. I2—the transfer temperature T.sub.TRANSFER is at most 75° C., at most 80° C., or at most 85° C., or at most 90° C., or at most 95° C., or at most 100° C., or at most 105° C., or at most 110° C., or at most 115° C. I3—the transfer temperature T.sub.TRANSFER is between 60° C. and 70° C. I4—the transfer temperature T.sub.TRANSFER is between 65° C. and 75° C. I5—the transfer temperature T.sub.TRANSFER is between 70° C. and 80° C. I6—the transfer temperature T.sub.TRANSFER is between 75° C. and 85° C. I7—the transfer temperature T.sub.TRANSFER is between 80° C. and 90° C. I9—the transfer temperature T.sub.TRANSFER is between 85° C. and 95° C. I10—the transfer temperature T.sub.TRANSFER is between 90° C. and 100° C. I11—the transfer temperature T.sub.TRANSFER is between 95° C. and 105° C. I12—the transfer temperature T.sub.TRANSFER is between 105° C. and 115° C. I13—the transfer temperature T.sub.TRANSFER is above 115° C. I14: a dry film glass transition temperature T.sub.g.sup.dry_film([2.sup.nd component]) of the second ink component exceeds (e.g. by at least 5° C., or at least 10° C., or at least 12° C., at least 15° C., or at least 20° C. or, or at least 30° C., or at least 40° C.) the transfer temperature T.sub.TRANSFER; and a dry film glass transition temperature T.sub.g.sup.dry_film([5:1 2.sup.nd component:1.sup.st component]) of a 5:1 weight-ratio of the first and second components is less (e.g. by at least 5° C., or at least 10° C., or at least 12° C., at least 15° C., or at least 20° C. or at least 30° C., or at least 40° C.) than the transfer temperature T.sub.TRANSFER.
A discussion of
(52)
(53) In the example of
(54) In the non-limiting example of
(55)
(56) One example of operation of the system of
(57) In
(58)
(59)
(60) Blanket
(61) The ITM may be manufactured in the manner described by
(62) With reference now to
(63) In some embodiments, carrier contact surface 12 may be a well-polished flat surface having a roughness (Ra) of at most about 50 nm, at most 30 nm, at most 20 m, at most 15 nm, at most 12 nm, or more typically, at most 10 nm, at most 7 nm, or at most 5 nm. In some embodiments, carrier contact surface 12 may between 1 and 50 nm, between 3 and 25 nm, between 3 and 20 nm, or between 5 nm and 20 nm.
(64) The hydrophilic properties of the carrier contact surface 12 are described herein below.
(65) In some embodiments, carrier 10 may be inflexible, being formed, for example, of a sheet of glass or thick sheet of metal.
(66) In some embodiments, carrier 10 may advantageously be formed of a flexible foil, such as a flexible foil mainly consisting of, or including, aluminum, nickel, and/or chromium. In one embodiment, the foil is a sheet of aluminized PET (polyethylene terephthalate, a polyester), e.g., PET coated with fumed aluminum metal. The top coating of aluminum may be protected by a polymeric coating, the sheet typically having a thickness of between 0.05 mm and 1.00 mm so as to remain flexible, but difficult to bend through a small radius, so as to avert wrinkling.
(67) In some embodiments, carrier 10 may advantageously be formed of an antistatic polymeric film, for example, a polyester film such as PET. The anti-static properties of the antistatic film may be achieved by various means known to those of skill in the art, including the addition of various additives (such as an ammonium salt) to the polymeric composition.
(68) In a step of the present ITM manufacturing method, the results of which are shown in
(69) The fluid first curable composition of layer 16 may include an elastomer, typically made of a silicone polymer, for example, a polydimethylsiloxane, such as a vinyl-terminated polydimethylsiloxane.
(70) In some embodiments, the fluid first curable material includes a vinyl-functional silicone polymer, e.g., a vinyl-silicone polymer including at least one lateral vinyl group in addition to the terminal vinyl groups, for example, a vinyl-functional polydimethyl siloxane.
(71) In some exemplary embodiments, the fluid first curable material includes a vinyl-terminated polydimethylsiloxane, a vinyl-functional polydimethylsiloxane including at least one lateral vinyl group on the polysiloxane chain in addition to the terminal vinyl groups, a cross-linker, and an addition-cure catalyst, and optionally further includes a cure retardant.
(72) As is known in the art, the curable adhesive composition may include any suitable amount of addition cure catalyst, typically at most 0.01% of the pre-polymer, on a per mole basis.
(73) Exemplary formulations for the fluid first curable material are provided herein below in the Examples.
(74) Layer 16 of the fluid first curable composition is applied to carrier contact surface 12, and is subsequently cured. Layer 16 may be spread to the desired thickness using, for example, a doctor blade (a knife on a roll), without allowing the doctor blade to contact the surface that will ultimately act as the ink-transfer surface 14 of the ITM, such that imperfections in the doctor blade will not affect the quality of the finished product. After curing, “release” layer 16 may have a thickness of between about 2 micrometers and about 200 micrometers. An apparatus in which such step and method can be implemented is schematically illustrated in
(75) For example, the above-detailed release layer formulation may be uniformly applied upon a PET carrier, leveled to a thickness of 5-200 micrometers (μ), and cured for approximately 2-10 minutes at 120-130° C. Surprisingly, the hydrophobicity of the ink transfer surface of the release layer so prepared, as assessed by its receding contact angle (RCA) with a 0.5-5 microliter (μl) droplet of distilled water, may be around 60°, whereas the other side of the same release layer (which served to approximate the hydrophobicity of a layer conventionally prepared with an air interface) may have an RCA that is significantly higher, typically around 90°. PET carriers used to produce ink-transfer surface 14 may typically display an RCA of around 40° or less. All contact angle measurements were performed with a Contact Angle analyzer—Krüss™ “Easy Drop” FM40Mk2 and/or a Dataphysics OCA15 Pro (Particle and Surface Sciences Pty. Ltd., Gosford, NSW, Australia).
(76) In a subsequent step of the method, the results of which are shown in
(77) While compliance layer 18 may have the same composition as that of release layer 16, material and process economics may warrant the use of less expensive materials. Moreover, compliance layer 18 typically is selected to have mechanical properties (e.g., greater resistance to tension) that differ from release layer 16. Such desired differences in properties may be achieved, by way of example, by utilizing a different composition with respect to release layer 16, by varying the proportions between the ingredients used to prepare the formulation of release layer 16, and/or by the addition of further ingredients to such formulation, and/or by the selection of different curing conditions. For instance, the addition of filler particles may favorably increase the mechanical strength of compliance layer 18 relative to release layer 16.
(78) In some embodiments, compliance layer 18 may include various rubbers. Preferably such rubbers are stable at temperatures of at least 100° C., and may include rubbers such as alkyl acrylate copolymer rubbers (ACM), methyl vinyl silicone rubber (VMQ), ethylene propylene diene monomer rubber (EPDM), fluoroelastomer polymers, nitrile butadiene rubber (NBR), ethylene acrylic elastomer (EAM), and hydrogenated nitrile butadiene rubber (HNBR).
(79) As a non-limiting example, Silopren® LSR 2530 (Momentive Performance Materials Inc., Waterford N.Y.), a two-component liquid silicone rubber, in which the two components are mixed at a 1:1 ratio, was applied to the cured release layer 16 previously described. The silicone rubber mixture was metered/leveled with a knife blade to obtain an incipient compliance layer 18 having a thickness of about 250 micrometers, which was then cured for approximately 5 minutes at 150-160° C.
(80) In a subsequent step of the method, the results of which are shown in
(81) Alternatively, support layer 20 may be separately formed as a reinforcement layer, including such fibers embedded and/or impregnated within the independently cured resin. In this case, support layer 20 may be attached to compliance layer 18 via an adhesive layer, optionally eliminating the need to cure the support layer 20 in situ. Generally, support layer 20, whether formed in situ on compliance layer 18 or separately, may have a thickness of between about 100 micrometers and about 500 micrometers, part of which is attributed to the thickness of the fibers or the fabric, which thickness generally varies between about 50 micrometers and about 300 micrometers. However, the support layer thickness is not limiting. For heavy-duty applications, by way of example, the support layer may have a thickness of more than 200 micrometers, more than 500 micrometers, or 1 mm or more.
(82) For example, to the multi-layered ITM structure described herein, including a vinyl-functionalized release coating 16 and a two-component silicone rubber compliance layer 18, was applied a support layer 20 including woven fabric of glass fibers. The glass fiber fabric, having a thickness of about 100 micrometers, was a plain weave fabric having 16 yarns/cm in perpendicular directions. The glass fiber fabric was embedded into a curable fluid including a liquid silicone rubber Silopren® LSR 2530 corresponding to the compliance layer. Overall, the resulting support layer 20 had a thickness of about 200 micrometers and was cured at 150° C. for approximately 2-5 minutes. Preferably, denser weave fabrics (e.g., having 24×23 yarns/cm) may be used.
(83) Following the in situ formation, or attachment, of support layer 20, additional layers may be built up on the reverse side thereof, as required.
(84) As mentioned, all layers (e.g., 18, 20, 22, 24, or any intervening adhesive or priming layer and the like) added to the release layer of the ITM jointly form the base of the structure, as shown with respect to base 200 in
(85) Before the ITM is used, it is necessary to remove carrier 10 to expose ink-transfer surface 14 of release layer 16, as illustrated in
(86) If the carrier 10 is a flexible foil, it may be preferred to leave it in place on the ITM until such time as the ITM is to be installed into a printing system. The foil will act to protect the ink-transfer surface 14 of the ITM during storage, transportation and installation. Additionally, carrier 10 can be replaced, following completion of the manufacturing process, by an alternative foil that is suitable as a protective film.
(87)
(88) In some embodiments, the need for loop conveyor 100 is obviated: carrier 10 is directly tensioned between rollers 40 and 42. Unprocessed carrier 10 is unwound from unwinding roller 40, and after passing through stations 50a and 50b, is rewound onto winding roller 42.
(89) Though not illustrated in the Fig., the apparatus may further include upstream of the dispensing station a “surface treatment” station facilitating the subsequent application of a curable composition, or its attachment to the carrier contact surface or incipient layer as the case may be. As mentioned in relation with the carrier, the optional surface treatment station (not shown) can be suitable for physical treatment (e.g., corona treatment, plasma treatment, ozonation, etc.).
(90)
(91)
(92)
(93)
(94) The method disclosed herein includes forming a layer of a fluid first curable material with one side of the layer contacting a carrier contact surface, the layer constituting an incipient release layer. The carrier contact surface functions to protect the incipient release layer, giving the ink transfer layer desired properties, while the carrier acts as a physically robust support structure onto which other layers are added to form the ITM, until the ITM is complete. As a result, many potential sources of defect are avoided. Moreover, the finish of the ink transfer surface is primarily, if not exclusively, determined by the carrier contact surface.
(95)
(96) The above-described release layer structures of the present disclosure, produced from addition-cure formulations, may contain substantially no functional groups, or an insubstantial amount (e.g., an insubstantial amount of OH groups), covalently attached within the polymer matrix. Such functional groups may include moieties such as C═O, S═O, and OH, by way of example.
(97) Because these release layer structures contain, at most, an insubstantial amount of such functional groups, it would be expected that the release layers thereof would be highly hydrophobic. The release layer surfaces produced by this method may actually be somewhat hydrophilic, and appreciably more hydrophilic than corresponding release layers, i.e., release layers having the same composition, but manufactured using the conventional curing technique in which the release layer is exposed to air (“standard air curing”). It is believed that the intimate contact between the carrier contact surface and the incipient release layer surface, the somewhat hydrophilic properties of the carrier contact surface are induced in the release layer surface.
(98) As discussed hereinabove, ITM release layers having low surface energies may facilitate transfer of the dried ink image to the printing substrate. However, during the ink reception stage, the aqueous ink drops jetted onto such a low-energy, hydrophobic release layer tend to bead after the initial impact, thereby compromising image quality. Higher-energy, less hydrophobic release layers may mitigate this effect, but may be detrimental to image transfer quality. It has been found that the release layer structures disclosed herein may have release surfaces of characteristically moderated hydrophobicity, as manifested by receding contact angles for distilled water of at most 80°, or at most 70°, typically, at most 60°, or at most 50°, and more typically, 30°-60°, 35°-60°, 30°-55°, 30°-50°, 30°-45°, or 35°-50°. It has been found, however, that both the ink reception and the transfer of the dry, heated ink image may be of good quality.
(99) It must be emphasized that yet lower values of the receding contact angle (and the dynamic contact angle discussed herein below) may be achieved by employing carrier surfaces having higher hydrophilicity (lower contact angles with respect to drops of distilled water), and/or by corona (or similar) treatment.
(100) It is believed that the above-described induced surface properties improve the interactions between polar groups (e.g., O—Si—O) on the release layer surface and corresponding polar moieties (e.g., OH groups in the water) in the aqueous liquids (e.g., aqueous inkjet inks) deposited thereon, thereby contributing to the reception of the jetted ink drops. Subsequently, after drying the ink and heating of the ink film to transfer temperatures, these interactions are weakened, enabling complete transfer of the dry or substantially dry ink image. Thus, the performance of the inventive release layer structure—at both the ink reception stage and the ink film transfer stage—is appreciably better than would have been expected for a release layer having moderate hydrophobicity, but devoid of the special surface structure and properties induced by the carrier contact surface.
(101) Binders
(102) Binders play an important role in the transferability of the dried 1.sup.st ink component, and the dried ink image containing both ink components, from the release layer of the ITM. Binders also play an important role in the adhesion of the dried ink image to the printing substrate.
(103) Various families of binders may be utilized within the 1.sup.st ink formulations of the present invention, including polystyrene-acrylate co-polymers, poly-acrylate polymers, polyurethanes (e.g., aliphatic polyurethanes or anionic aliphatic polyurethanes), urethane-acrylate co-polymers, and polyesters (e.g., a polyethylene terephthalate).
(104) Exemplary styrene-acrylic (or polystyrene-acrylate) copolymers include Joncryl® 77E (Tg=35° C.), Joncryl® 586 (Tg=66° C.), Joncryl® 90 (Tg=110° C.), Joncryl® 8085 (Tg=57° C.), and Joncryl® ECO 2177 (Tg=21° C.).
(105) Exemplary polyurethanes include NeoRez® R-563, an anionic aliphatic polyurethane from DSM-PUD.
(106) Exemplary urethanes include NeoRez® R-600, an aliphatic urethane dispersion from DSM-PUD.
(107) Exemplary acrylic or polyacrylic binders include Joncryl® 538, an acrylic polymer emulsion (Tg=64° C.).
(108) Exemplary polyesters include Plascoat Z-105 (Tg 52° C.), Plascoat Z-730 (Tg 46° C.), Plascoat Z-750 (Tg 52° C.) (all from GOO Chemicals).
(109) The binders may be provided in various forms, such as dispersions or emulsions, with water typically being the major carrier liquid.
(110) The binders should be sufficiently soft at the process transfer temperature such that the dried binder is sufficiently tacky (and cohesive) to fully transfer from the release layer to the printing substrate. Moreover, the binder must facilitate the transfer of the dried ink image (i.e., including the dried 2.sup.nd ink component), which may contain components having poor transferability properties (e.g., the dried 2.sup.nd ink component). Consequently, the glass transition temperature of the binders is typically at most 100° C. or at most 90° C., and more typically, at most 85° C., at most 80° C., at most 75° C., or at most 70° C.
(111) It must be emphasized that the ink formulations may contain at least one plasticizing agent, which may serve to reduce the glass transition temperature of the binders. In some cases, a plasticizing binder having a relatively low glass transition temperature may be introduced to the 1.sup.st ink component. This plasticizing binder may serve to lower the glass transition temperature (and required transfer temperature) of the dried 1.sup.st ink component, and/or the glass transition temperature (and required transfer temperature) of the dried ink image.
(112) For jetted (typically digitally applied) 1.sup.st ink component formulations, the binder concentration (on the basis of binder solids) may be within a range of 5%-28% of the formulation, on a weight basis. For 1.sup.st ink component formulations that are spread as a continuous layer, however, this binder concentration may be 5%-55%.
(113) Including other non-volatile content present in the 1.sup.st ink component formulations—including plasticizers, surfactants, etc.—the total non-volatile concentration of the formulation may thus be 8% to 35% for the jetted formulations, and 8% to 65% for the spread formulations.
(114) Plasticizing Agents
(115) Plasticizing agents may be added to enhance the plasticity of the material, bringing down the required temperature at which the dry film may be transferred to the printing substrate.
(116) Families of plasticizing agents include urea derivatives and sorbitan derivatives. Such sorbitan derivatives may include derivatives such as sorbitan esters (such as SPAN 20, SPAN 40, SPAN 60, and SPAN 80) and polyethoxylated sorbitan esters (e.g., polyethoxylated sorbitan monoesters such as TWEEN 20, TWEEN 40, TWEEN 60, and TWEEN 80), which may be particularly suitable. The structure of a polyethoxylated sorbitan monoester is provided below:
(117) ##STR00001##
where R is the alkyl group of a fatty acid and the total number of moles of ethylene oxide is v+x+y. Typical plasticizing agents within this family include polyethoxyethylene sorbitan monolaurate, polyethoxyethylene sorbitan monopalmitate, polyethoxyethylene sorbitan monolstearate, polyethoxyethylene sorbitan tristearate and polyethoxyethylene sorbitan monooleate. The plasticizing agents may also behave as nonionic surfactants.
(118) In some embodiments, the HLB no. of the plasticizing agent may be at least 7, at least 8, at least 9, or at least 10 (by way of example, the HLB no. of polyethoxyethylene (20) sorbitan monooleate is 15.0). The HLB no. of the polyethoxylated sorbitan monoester molecule may be adjusted by increasing or reducing the number of ethylene oxide units to (respectively) increase or reduce the hydrophilicity (and generally correspondingly, the HLB no.).
(119) Jetted formulations of the present invention may contain at least 1%, at least 2%, at least 3%, or at least 4% of such surfactants, by weight, and more typically, within a range of 1%-7%, 1.5%-7%, 2%-7%, 2.5%-7%, 3%-7%, 1.5%-6%, 2%-6%, 2.5%-6%, 3%-6%, or 2.5%-5.5%.
(120) Surfactants
(121) Surfactants may be utilized to lower the surface tension of the formulations, and/or to improve wetting characteristics, e.g., with the release layer.
(122) Various classes of surfactants may be suitable, including anionic surfactants (e.g., SDS). Surfactants of particular suitability for use in conjunction with the present silicone-based release layer include non-ionic surfactants. These may include siloxanes and siloxane copolymers such as polyether siloxane copolymers. Such surfactants are commercially available, e.g., as Tego® Wet 240, Tego® Wet 280, Tego® Twin 4100, Byk® 348 Byk® 349, and Byk® 3455.
(123) Jetted formulations of the present invention may contain at least 1%, at least 2%, at least 3%, or at least 4% of such surfactants, by weight, and more typically, within a range of 1%-5%, 1.5%-5%, 2%-5%, 2.5%-5%, 3%-5%, 1.5%-4.5%, 2%-4.5%, 2.5%-4.5%, 3%-4.5%, or 2.5%-4%.
(124) Spread formulations of the present invention may contain the same amounts of such surfactants as jetted formulations. However, the spread formulations may be devoid of such surfactants. More typically, the spread formulations may contain 0%-2%, 0.1%-2%, or 0.3%-1.5% of such surfactants.
(125) Surface Energy Modifiers
(126) Surface energy modifiers may be used to reduce the surface energy of the formulation. This may enhance wetting, e.g., wetting of the release layer surface.
(127) Families of such surface energy modifiers include silicone-based surfactants such as polysiloxane-polyoxyalkylene copolymers. Such surface energy modifiers are commercially available, e.g., as Byk® 307, Byk® 333, and Byk® 378.
(128) pH Modifiers pH modifiers may be used to raise or lower the acidity to within a desired range. Typically, the pH modifiers are basic, and may include an amine functionality. Specific examples include ammonia, triethanolamine, 2-Amino-2-methyl-1-propanol (commercially available as AMP 95®), and dimethylethylamine
Humectants
(129) Humectants may serve to reduce the tendency of the formulation to dry, which may reduce clogging of nozzles and alleviate other disadvantageous phenomena. Families of humectants include, by way of example, alcohols, polyols, and glycols.
(130) The concentration of the humectant or humectants within the 1.sup.st and 2.sup.nd ink components may typically be within the range of 5%-50% for jetted formulations, and may typically be within the range of 0%-25% for spread formulations.
(131) Additional Discussion
(132) Inventive concept 1. A method of printing a digital image on a printing substrate using an intermediate transfer member (ITM), the method comprising: a. providing: i. a first aqueous ink component, the first aqueous ink component optionally being transparent; and ii. a second aqueous ink component comprising colorant particles b. delivering a quantity of the first ink component to a target surface of the ITM, to cover a portion of the target surface with a wet volume of the first ink component; c. effecting only a partial drying of the wet volume to produce a partially-dried layer of the first ink component on the ITM; d. digitally depositing droplets of the second ink component onto the partially-dried layer of the first component so as to form a wet, colored ink-image on the ITM, wherein the partially-dried layer of the first ink component is sufficiently moist and permeable such that some or all the colorant particles of the second ink component penetrate into the partially-dried layer of the first ink component; e. at least partially drying the wet, colored ink-image; f. transferring the at least partially dried ink-image from the ITM to printing substrate. Inventive concept 2. The method of claim 1 wherein the at least partially dried ink-image is tacky upon transfer from the ITM in step (f). Inventive concept 3. The method of any preceding inventive concept wherein the drying of step (e) is performed at least in part by heating and/or the at least partially dried ink-image is heated on the ITM before the transfer. Inventive concept 4. The method of any preceding inventive concept wherein (i) the at least partial drying is performed to produce a dried, tacky ink-image-bearing residue film; and (ii) the dried, tacky ink-image-bearing residue film is transferred from the ITM to the printing substrate in step Inventive concept 5. A method of printing a digital image on a printing substrate using an intermediate transfer member (ITM), the method comprising: a. providing: i. a first aqueous ink component, the first aqueous ink component optionally being transparent; and ii. a second aqueous ink component comprising colorant particles, b. delivering a quantity of the first ink component to a target surface of the ITM, to cover a portion of the target surface with a wet volume of the first ink component; c. effecting only a partial drying of the wet volume to produce a partially-dried layer of the first ink component on the ITM; d. digitally depositing droplets of the second ink component onto the partially-dried layer of the first component so as to form a wet, colored ink-image on the ITM, wherein the partially-dried layer of the first ink component is sufficiently moist and permeable such that some or all the colorant particles of the second ink component penetrate into the partially-dried layer of the first ink component; e. at least partially drying and heating of the wet, colored ink-image to produce a dried, tacky ink-image-bearing residue film at a transfer temperature T.sub.TRANSFER; and f. effecting transfer of the dried, tacky ink-image-bearing residue film that is at the transfer temperature T.sub.TRANSFER from the ITM to a printing substrate to produce the digital image on the printing substrate. Inventive concept 6. The method of any preceding inventive concept, wherein the first aqueous ink component that is provided in step (a) is transparent. Inventive concept 7. The method of any preceding inventive concept, wherein the first ink component is delivered to the ITM surface in step (b) by droplet deposition, optionally by ink-jetting. Inventive concept 8. The method of any preceding inventive concept, wherein the first ink component is delivered to the ITM surface by droplet deposition according to a pattern of the ink-image to be subsequently formed by the digital depositing of the droplets of the second ink component. Inventive concept 9. The method of any preceding inventive concept, wherein the second component is delivered in step (d) by ink-jetting. Inventive concept 10. The method of inventive concept 8, wherein during ink-jetting of the second ink component and under jetting conditions, the second aqueous ink component is a resoluble ink component. Inventive concept 11. The method of any preceding inventive concept, wherein prior to impact between the droplets of the second ink component and the layer of the first ink component, a liquid content of the layer of the first ink component is at least 10% wt/wt or at least 20% wt/wt or at least 30% wt/wt or at least 40% wt/wt. Inventive concept 12. The method of any one of inventive concepts 1-10 wherein immediately before impact between the droplets of the second ink component and the layer of the first ink component, a liquid content of the layer of the first ink component is at least 10% wt/wt or at least 20% wt/wt or at least 30% wt/wt or at least 40% wt/wt. Inventive concept 13. The method of any one of inventive concepts 11-12 wherein the liquid content of the layer of the first ink component is at least 20% wt/wt. Inventive concept 14. The method of any one of inventive concepts 11-12 wherein the liquid content of the layer of the first ink component is at least 30% wt/wt. Inventive concept 15. The method of any one of inventive concepts 11-12 wherein the liquid content of the layer of the first ink component is at least 40% wt/wt. Inventive concept 16. The method of any preceding inventive concept, wherein upon impact between the droplets of the second ink component and the layer of the first ink component, some or all the colorant particles of the second ink component penetrate into the partially-dried layer of the first ink component. Inventive concept 17. The method of inventive concept 16, wherein at least pP % of the colorant particles of the second ink component penetrate into and mixed with the partially-dried layer of the first ink component, and wherein pP is a positive number having a value of at least 10. Inventive concept 18. The method of inventive concept 15, for a given deposited droplet of the second ink component, at least pP % of the colorant particles thereof penetrate into and mixed with the partially-dried layer of the first ink component, and wherein pP is a positive number having a value of at least 10. Inventive concept 19. The method of any one of inventive concepts 17-18 wherein a value of pP is at least 20. Inventive concept 20. The method of any one of inventive concepts 17-18 wherein a value of pP is at least 30. Inventive concept 21. The method of any one of inventive concepts 17-18 wherein a value of pP is at least 50. Inventive concept 22. The method of any one of inventive concepts 17-18 wherein a value of pP is at least 70. Inventive concept 23. The method of any one of inventive concepts 17-18 wherein a value of pP is at least 80. Inventive concept 24. The method of any preceding inventive concept wherein upon transfer from the ITM, a temperature of the least partially dried ink-image is T.sub.Transfer. Inventive concept 25. The method of any preceding inventive concept, wherein: A. a dry film glass transition temperature T.sub.g.sup.dry_film([2.sup.nd component]) of the second ink component exceeds the transfer temperature T.sub.TRANSFER by at least X° C., where X is a first positive number; and B. a dry film glass transition temperature T.sub.g.sup.dry_film([5:1 2.sup.nd component:1.sup.st component]) of a 5:1 weight-ratio of the first and second components is less than the transfer temperature T.sub.TRANSFER by at least Y° C., where Y is a second positive number. Inventive concept 26. The method of any preceding inventive concept wherein: A. a dry film glass transition temperature T.sub.g.sup.dry_film([2.sup.nd component]) of the second ink component exceeds the transfer temperature T.sub.TRANSFER by at least X° C., where X is a first positive number; and B. a dry film glass transition temperature T.sub.g.sup.dry_film([1.sup.st component]) of the first ink component is less than the transfer temperature T.sub.TRANSFER by at least Y° C., where Y is a second positive number. Inventive concept 27. The method of any one of inventive concepts 25-26, wherein a value of X is at least 5 or at least 10 or at least 15 or at least 20 or at least 30 or at least 40. Inventive concept 28. The method of any one of inventive concepts 25-26, wherein a value of Y is at least 5 or at least 10 or at least 15 or at least 20 or at least 30 or at least 40. Inventive concept 29. The method of any one of inventive concepts 25-26, wherein a value of X is at least 5. Inventive concept 30. The method of any one of inventive concepts 25-26, wherein a value of X is at least 10. Inventive concept 31. The method of any one of inventive concepts 25-26, wherein a value of X is at least 15. Inventive concept 32. The method of any one of inventive concepts 25-26, wherein a value of X is at least 20. Inventive concept 33. The method of any one of inventive concepts 25-26, wherein a value of X is at least 30. Inventive concept 34. The method of any one of inventive concepts 25-26, wherein a value of X is at least 40. Inventive concept 35. The method of any one of inventive concepts 25-26 or 29-34, wherein a value of Y is at least 5. Inventive concept 36. The method of any one of inventive concepts 25-26 or 29-34, wherein a value of Y is at least 10. Inventive concept 37. The method of any one of inventive concepts 25-26 or 29-34, wherein a value of Y is at least 15. Inventive concept 38. The method of any one of inventive concepts 25-26 or 29-34, wherein a value of Y is at least 20. Inventive concept 39. The method of any one of inventive concepts 25-26 or 29-34, wherein a value of Y is at least 30. Inventive concept 40. The method of any one of inventive concepts 25-26 or 29-34, wherein a value of Y is at least 40. Inventive concept 41. The method of any preceding inventive concept wherein a ratio between A. a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2.sup.nd component], T.sub.TRANSFER) of the second aqueous ink component at the transfer temperature T.sub.TRANSFER; and B. a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([5:1 2.sup.nd component:1.sup.st component], T.sub.TRANSFER) of a 5:1 weight-ratio of the first and second components at the transfer temperature T.sub.TRANSFER is at least a positive number V, a value of V being at least 2.5 or at least 3 or at least 4 or at least 5 or at least 7 or at least 10 or at least 15 or at least 25 or at least 50. Inventive concept 42. The method of inventive concept 41 wherein a value of V is at least 3. Inventive concept 43. The method of inventive concept 41 wherein a value of V is at least 4. Inventive concept 44. The method of inventive concept 41 wherein a value of V is at least 5. Inventive concept 45. The method of inventive concept 41 wherein a value of V is at least 7. Inventive concept 46. The method of inventive concept 41 wherein a value of V is at least 10. Inventive concept 47. The method of inventive concept 41 wherein a value of V is at least 15. Inventive concept 48. The method of inventive concept 41 wherein a value of V is at least 25. Inventive concept 49. The method of inventive concept 41 wherein a value of V is at least 50. Inventive concept 50. The method of any preceding inventive concept wherein a ratio between A. a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([2.sup.nd component], T.sub.TRANSFER) of the second aqueous ink component at the transfer temperature T.sub.TRANSFER; and B. a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component], T.sub.TRANSFER) of the first aqueous ink component at the transfer temperature T.sub.TRANSFER is at least a positive number W, a value of W being 2.5. or at least 3 or at least 4 or at least 5 or at least 7 or at least 10 or at least 15 or at least 25 or at least 50. Inventive concept 51. The method of inventive concept 50, wherein the value of W is at least 3. Inventive concept 52. The method of inventive concept 50, wherein the value of W is at least 4. Inventive concept 53. The method of inventive concept 50, wherein the value of W is at least 5. Inventive concept 54. The method of inventive concept 50, wherein the value of W is at least 7. Inventive concept 55. The method of inventive concept 50, wherein the value of W is at least 10. Inventive concept 56. The method of inventive concept 50, wherein the value of W is at least 15. Inventive concept 57. The method of inventive concept 50, wherein the value of W is at least 25. Inventive concept 58. The method of claim 50, wherein the value of W is at least 50. Inventive concept 59. The method of any preceding claim, performed without forming a gel or gelatinous phase of the first aqueous ink component on the ITM surface. Inventive concept 60. The method of any preceding claim, wherein the provided first aqueous ink component (i) comprises between 40% wt/wt and 70% wt/wt water and (ii) further comprises at least 10% wt/wt binder. Inventive concept 61. The method of any previous claim wherein a surface energy (at 25° C.) of the ITM target surface is at least 20 dynes/cm or at least 21 dynes/cm or at least 22 dynes/cm or at least 23 dynes/cm. Inventive concept 62. The method of any previous claim, wherein the ITM comprises a silicone-based release layer surface. Inventive concept 63. The method of Inventive concept 62, wherein the silicone-based release layer surface is sufficiently hydrophilic to satisfy at least one of the following properties: (i) a receding contact angle of a drop of distilled water deposited on the silicone-based release layer surface is at most 60°; and (ii) a 10-second dynamic contact angle (DCA) of a drop of distilled water deposited on the silicone-based release layer surface is at most 108°. Inventive concept 64. The method of any of inventive concepts 63, wherein the 10 second DCA is at most 108°, at most 106°, at most 103°, at most 100°, at most 96°, at most 92°, or at most 88°, optionally at least 60°, at least 65°, at least 70°, at least 75°, at least 78°, at least 80°, at least 82°, at least 84°, or at least 86°, and further optionally, within a range of 60 to 108°, 65 to 105°, 70 to 105°, 70 to 100°, 70 to 96°, 70 to 92°, 75 to 105°, 75 to 100°, 80 to 105°, 80 to 100°, 85 to 105°, or 85 to 100°. Inventive concept 65. The method of any one of inventive concepts 63-64, wherein the silicone-based release layer surface is sufficiently hydrophilic such that a receding contact angle of a drop of distilled water deposited on the silicone-based release layer surface is at most 60°. Inventive concept 66. The method of any one of inventive concepts 63-65, wherein the silicone-based release layer surface is sufficiently hydrophilic such that a 10-second dynamic contact angle (DCA) of a drop of distilled water deposited on the silicone-based release layer surface is at most 108°. Inventive concept 67. The method of any one of inventive concepts 63-66, wherein the provided ITM comprises a support layer and a release layer having said silicone-based release layer surface and a second surface that (i) opposes said silicone-based release layer surface, and (ii) is attached to said support layer, and wherein said release layer is formed of an addition-cured silicone material, and wherein a thickness of said release layer is at most 500 micrometers (μm). Inventive concept 68. The method of inventive concept 67, wherein the release layer of the provided ITM has the following structural property: said addition-cured silicone material consists essentially of an addition-cured silicone, or contains, by weight, at least 95% of said addition-cured silicone. Inventive concept 69. The method of any one of inventive concepts 67-68, wherein functional groups within said silicone based release layer surface of the provided ITM make up at most 3%, by weight, of said addition-cured silicone material. Inventive concept 70. The method of any one of inventive concepts 67-69, wherein a polyether glycol functionalized polydimethyl siloxane is impregnated in said addition-cured silicone material of the provided ITM. Inventive concept 71. The method of any one of inventive concepts 67-70, wherein the release layer of the provided ITM is adapted such that polar groups of the ink reception surface have an orientation away from or opposite from the second surface. Inventive concept 72. The method of any one of inventive concepts 63 to 71, wherein a surface hydrophobicity of said silicone-based release layer surface of the provided ITM is less than a bulk hydrophobicity of the cured silicone material within the release layer, the surface hydrophobicity being characterized by a receding contact angle of a droplet of distilled water on the ink reception surface, the bulk hydrophobicity being characterized by a receding contact angle of a droplet of distilled water disposed on an inner surface formed by exposing an area of the cured silicone material within the release layer to form an exposed area. Inventive concept 73. The method of any of inventive concepts 63-72, further comprising, prior to the performing of steps b-f, pre-treating the silicone-based release surface with at least one of a corona treatment, a plasma treatment, and an ozonation treatment, thereby reducing a hydrophobicity of the silicone-based release surface. Inventive concept 74. The method of any preceding inventive concept, wherein the provided first aqueous ink component comprises at least 35% wt/wt water or at least 40% wt/wt water or at least 50% wt/wt water or at least 55% wt/wt water. Inventive concept 75. The method of any preceding inventive concept, wherein the provided first aqueous ink component comprises at most 75% wt/wt water or at most 70% wt/wt water or at most 65% wt/wt water. Inventive concept 76. The method of any preceding inventive concept, wherein the provided first aqueous ink component comprises between 35% wt/wt and 75% wt/wt water or between 40% wt/wt and 75% wt/wt water or between 40% wt/wt and 70% wt/wt water. Inventive concept 77. The method of any preceding inventive concept, wherein a 60° C. evaporation load of the provided first aqueous ink component is at most 10:1, at most 9:1, at most 8:1, at most 7:1, at most 6:1, at most 5:1, at most 4:1, at most 3.5:1, or at most 3:1. Inventive concept 78. The method of any preceding inventive concept, wherein a 60° C. evaporation load of the provided first aqueous ink component is at least 2:1, at least 2.2:1, or at least 2.5:1. Inventive concept 79. The method of any preceding inventive concept, wherein a 60° C. evaporation load of the provided first aqueous ink component is between 2:1 and 10:1, or between 2:1 and 8:1. Inventive concept 80. The method of any preceding inventive concept, wherein a 60° C. evaporation load of the provided first aqueous ink component is between 2:1 and 9:1. Inventive concept 81. The method of any preceding inventive concept, wherein a 60° C. evaporation load of the provided first aqueous ink component is between 2:1 and 8:1. Inventive concept 82. The method of any preceding inventive concept, wherein a 60° C. evaporation load of the provided first aqueous ink component is between 2.5:1 and 7:1. Inventive concept 83. The method of any preceding inventive concept, wherein a 60° C. evaporation load of the provided first aqueous ink component is between 2.5:1 and 5:1. Inventive concept 84. The method of any preceding inventive concept, wherein a 60° C. evaporation load of the provided first aqueous ink component is between 2.5:1 and 4:1. Inventive concept 85. The method of any preceding inventive concept, wherein a 60° C. evaporation load of the provided first aqueous ink component is between 2.5:1 and 3.5:1 Inventive concept 86. The method of any preceding inventive concept, wherein a 60° C. evaporation load is between 2.8:1 and 4:1. Inventive concept 87. The method of any preceding inventive concept, wherein a 60° C. evaporation load of the provided first aqueous ink component is between 2.8:1 and 3.5:1. Inventive concept 88. The method of any preceding inventive concept wherein the provided first aqueous ink component comprises at least 6% wt/wt or at least 7% wt/wt or at least 8% wt/wt or at least 9% wt/wt or at least 10% wt/wt or at least 11% wt/wt or at least 12% wt/wt binder. Inventive concept 89. The method of any preceding inventive concept, wherein a 25° C. static surface tension of the provided first aqueous ink component is at most 32 dynes/cm, at most 30 dynes/cm or at most 28 dynes/cm, and optionally, at least 20 dynes/cm, at least 22 dynes/cm, or at least 23 dynes/cm, and further optionally, within a range of 20-33 dynes/cm, 21-31 dynes/cm, 21-30 dynes/cm, 21-28 dynes/cm, 21-27 dynes/cm, or 21-26 dynes/cm. Inventive concept 90. The method of any preceding inventive concept wherein the provided first aqueous ink component is devoid of quaternary ammonium salts or comprises at most 1% wt/wt or at most 0.75% wt/wt or at most 0.5% wt/wt or at most 0.25% quaternary ammonium salts, or their neutralized counterparts. Inventive concept 91. The method of any preceding inventive concept, wherein a dynamic viscosity of the provided first aqueous ink component is at most 100 mPa.Math.s (millipascal seconds) or at most 80 mPa.Math.s. Inventive concept 92. The method of any preceding inventive concept, wherein a dynamic viscosity of the provided first aqueous ink component is at most 35 mPa.Math.s, at most 30 mPa.Math.s, at most 25 mPa.Math.s, at most 20 mPa.Math.s, or at most 15 mPa.Math.s. Inventive concept 93. The method of any preceding inventive concept, wherein a dynamic viscosity of the provided first aqueous ink component is at least 3 mPa.Math.s, at least 4 mPa.Math.s, at least 5 mPa.Math.s, or at least 6 mPa.Math.s. Inventive concept 94. The method of any preceding inventive concept, wherein the provided first aqueous ink component is devoid of organic solvents and/or comprises at most 3%, at most 2%, at most 1%, or at most 0.5%, or at most 0.25% or at most 0.1% by weight, organic solvents. Inventive concept 95. The method of any preceding inventive concept, wherein the provided first aqueous ink component is devoid of glycerol and/or comprises at most 3%, at most 2%, at most 1%, or at most 0.5%, or at most 0.25% or at most 0.1% by weight, glycerol. Inventive concept 96. The method of any preceding inventive concept, wherein the provided first aqueous ink component is devoid of chelating agents and/or comprises at most 3%, at most 2%, at most 1%, or at most 0.5%, or at most 0.25% or at most 0.1% by weight, chelating agents. Inventive concept 97. The method of any preceding inventive concept wherein, the provided first aqueous ink component is devoid of starch and/or comprises at most 3%, at most 2%, at most 1%, or at most 0.5%, or at most 0.25% or at most 0.1% by weight starch. Inventive concept 98. The method of any preceding inventive concept, wherein the provided first aqueous ink component is devoid of water soluble film-forming polymers and/or comprises at most 3%, at most 2%, at most 1%, or at most 0.5%, and more typically at most 0.25% or at most 0.1% by weight, water soluble film-forming polymers. Inventive concept 99. The method of any preceding inventive concept wherein a dry film glass transition temperature T.sub.g.sup.dry_film([1.sup.st component]) of the provided first ink component is at most 115° C., or at most 110° C., at most 105° C., or at most 100° C., or at most 95° C., or at most 90° C., or at most 85° C., or at most 80° C., or at most 75° C., or at most 70° C., or at most 65° C., or at most 60° C., or at most 65° C. Inventive concept 100. The method of any preceding inventive concept, wherein a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component], 115° C.) of the provided first ink component is at most 1*10.sup.7 mPa.Math.s or at most 8*10.sup.6 mPa.Math.s or at most 6*10.sup.6 mPa.Math.s or at most 4*10.sup.6 mPa.Math.s. Inventive concept 101. The method of any preceding inventive concept wherein a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component], 110° C.) of the provided first ink component is at most 1*10.sup.7 mPa.Math.s, or at most 8*10.sup.6 mPa.Math.s, or at most 6*10.sup.6 mPa.Math.s or at most 5*10.sup.6 mPa.Math.s or at most 4*10.sup.6 mPa.Math.s. Inventive concept 102. The method of any preceding inventive concept, wherein a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component], 105° C.) of the provided first ink component is at most 2*10.sup.7 mPa.Math.s, at most 1*10.sup.7 mPa.Math.s, or at most 8*10.sup.6 mPa.Math.s, or at most 6*10.sup.6 mPa.Math.s. Inventive concept 103. The method of any preceding inventive concept, wherein a dry ink film dynamic viscosity μ.sub.g.sup.dry_film([1.sup.st component], 100° C.) of the provided first ink component is at most 2*10.sup.7 mPa.Math.s, or at most 8*10.sup.6 mPa.Math.s, or at most 6*10.sup.6 mPa.Math.s. Inventive concept 104. The method of any preceding inventive concept, wherein a dry ink film dynamic viscosity μ.sub.g.sup.dry-film([1.sup.st component], 95° C.) of the provided first ink component is at most 4*10.sup.7 mPa.Math.s, at most 2*10.sup.7 mPa.Math.s, at most 1*10.sup.7 mPa.Math.s, at most 8*10.sup.6 mPa.Math.s, or at most 6*10.sup.6 mPa.Math.s. Inventive concept 105. The method of any preceding inventive concept wherein a dry ink film dynamic viscosity μ.sub.g.sup.dry-film([1.sup.st component], 90° C.) of the provided first ink component is at most 4*10.sup.7 mPa.Math.s, at most 2*10.sup.7 mPa.Math.s, at most 1.2*10.sup.7 mPa.Math.s, or more typically at most 1*10.sup.7 mPa.Math.s, at most 8*10.sup.6 mPa.Math.s, or at most 8*10.sup.6 mPa.Math.s. Inventive concept 106. The method of any preceding inventive concept wherein the provided second aqueous ink component comprises at least 40% wt/wt water or at least 45% wt/wt water or at least 50% wt/wt water or at least 55% wt/wt water or at least 60% wt/wt water or at least 65% wt/wt water. Inventive concept 107. The method of any preceding inventive concept wherein the provided second aqueous ink component comprises at least 6% wt/wt solids, or at least 7% wt/wt solids, or at least 8% wt/wt solids, where the terms ‘solids’ refers to material that is solid at 60° C. Inventive concept 108. The method of any preceding inventive concept wherein the provided second aqueous ink component comprises at most 15% wt/wt solids, or at most 14% wt/wt solids, or at most 13% wt/wt solids, or at most 12% wt/wt solid, where the terms ‘solids’ refers to material that is solid at 60° C. Inventive concept 109. The method of any preceding inventive concept wherein the provided second aqueous ink component comprises between 7% wt/wt and 13% wt/wt solids.
(133) Inventive concept 110. The method of any preceding inventive concept wherein the provided second aqueous ink component comprises, as a wt % of the second ink component including the aqueous liquid carrier of the second aqueous ink component, at most 3% wt/wt or at most 2.5% wt/wt or at most 2% wt/wt or at most 1.5% wt/wt or at most 1% wt/wt or at most 0.5% wt/wt binder. Inventive concept 111. The method of any preceding inventive concept, wherein within the provided second aqueous ink component, a ratio between (i) a weight fraction of binder within the second aqueous ink component; and (ii) a weight fraction of pigment within the second aqueous ink component is at most 1.5:1 or at most 1.3:1 or at most 1.2:1 or at most 1.1:1 or at most 0.8:1, or at most 0.6:1, or at most 0.4:1. Inventive concept 112. The method of any preceding inventive concept wherein within the provided second aqueous ink component is a resoluble ink component. Inventive concept 113. The method of any preceding inventive concept wherein within the provided second aqueous ink component comprises nanoparticles for example as a primary colorant of the second aqueous ink component. Inventive concept 114. The method of any preceding inventive concept wherein a dry film glass transition temperature T.sub.g.sup.dry_film([2.sup.nd component]) of the second ink component (i.e. as a pure component) is at least 60° C., or at least 65° C., at least 70° C., or at least 75° C., at least 80° C., or at least 85° C., is at least 90° C., or at least 95° C., or at least 100° C., at least 105° C., or at least 110° C., or at least 115° C. Inventive concept 115. The method of any preceding inventive concept wherein a dry ink film dynamic viscosity μ.sub.g.sup.dry-film([2nd component], 115° C.) of the provided second component is at least 8*10.sup.6 mPa.Math.s, at least 1*10.sup.7 mPa.Math.s, at least 3*10.sup.7 mPa.Math.s, or at least 6*10.sup.7 mPa.Math.s. Inventive concept 116. The method of any preceding inventive concept wherein a dry ink film dynamic viscosity μ.sub.g.sup.dry-film(([2nd component], 110° C.) of the provided second component is at least 1*10.sup.7 mPa.Math.s, at least 3*10.sup.7 mPa.Math.s, at least 5*10.sup.7 mPa.Math.s, or at least 8*10.sup.7 mPa.Math.s. Inventive concept 117. The method of any preceding inventive concept wherein a dry ink film dynamic viscosity μ.sub.g.sup.dry-film([2nd component], 105° C.) is at least 1.2*10.sup.7 mPa.Math.s, at least 3*10.sup.7 mPa.Math.s, at least 5*10.sup.7 mPa.Math.s, or at least 1*10.sup.8 mPa.Math.s. Inventive concept 118. The method of any preceding inventive concept wherein a dry ink film dynamic viscosity μ.sub.g.sup.dry-film([2nd component], 100° C.) of the provided second component is at least 1.5*10.sup.7 mPa.Math.s, at least 3*10.sup.7 mPa.Math.s, at least 7*10.sup.7 mPa.Math.s, or at least 2*10.sup.8 mPa.Math.s. Inventive concept 119. The method of any preceding inventive concept wherein a dry ink film dynamic viscosity μ.sub.g.sup.dry-film([2nd component], 95° C.) of the provided second component is at least 2*10.sup.7 mPa.Math.s, at least 5*10.sup.7 mPa.Math.s, at least 1*10.sup.8 mPa.Math.s, or at least 3*10.sup.8 mPa.Math.s. Inventive concept 120. The method of any preceding inventive concept wherein a dry ink film dynamic viscosity μ.sub.g.sup.dry-film([2nd component], 90° C.)) of the provided second component is at least 2*10.sup.7 mPa.Math.s, at least 4*10.sup.7 mPa.Math.s, at least 6*10.sup.7 mPa.Math.s, at least 8*10.sup.7 mPa.Math.s, at least 1*10.sup.8 mPa.Math.s, at least 3*10.sup.8 mPa, or at least 5*10.sup.8 mPa. Inventive concept 121. The method of any preceding inventive concept wherein the provided first and second aqueous ink components collectively provide the following property: a ratio between (i) a weight fraction of binder in the first component and (ii) a weight fraction of binder in the second component is at least 1.5, or at least 1.75:1, or at least 2:1, or at least 2.25:1, or at least 2.25:1, or at least 3:1, or at least 4:1 or at least 5:1, or at least 6:1 or at least 7:1, or at least 8:1, or at least 9:1, or at least 10:1, or wherein this ratio is infinite. Inventive concept 122. The method of any preceding inventive concept wherein the provided first and second aqueous ink components collectively provide the following property: a ratio between (i) a weight fraction of solids in the first component and (ii) a weight fraction of solids in the second component is at least 1.8, at least 2.0, at least 2.2, at least 2.5, or at least 3.0, where the term ‘solids’ refers to material that is solid at 60° C. Inventive concept 123. The method of any preceding inventive concept wherein the provided first and second aqueous ink components collectively provide the following property: a difference T.sub.g.sup.dry_film([2nd component)−T.sub.g.sup.dry_film([1st component]) is at least 0° C., or at least 1° C., or at least 2° C., or at least 3° C., or at least 4° C., or at least 5° C., or at least 6° C., or at least 7° C., or at least 8° C., or at least 9° C., or at least 10° C., or at least 12° C., or at least 15° C. Inventive concept 124. The method of any preceding inventive concept, wherein the provided first and second aqueous ink components collectively provide the following property: a dry film glass transition temperature T.sub.g.sup.dry_film([5:1 2.sup.nd component:1.sup.st component]) of a 5:1 weight-ratio of the first and second components is less than 115° C., or less than 110° C., or less than 105° C., or less than 100° C., or less than 95° C., or less than 90° C., or less than 85° C., or less than 80° C., or less than 75° C., or less than 70° C., or less than 65° C., or less than 60° C., or less than 55° C. Inventive concept 125. The method of any preceding inventive concept wherein the provided first and second aqueous ink components collectively provide the following property: a dry ink film dynamic viscosity μ.sub.g.sup.dry-film([5:1 2.sup.nd component:1.sup.st component], 115° C.) of a 5:1 weight-ratio of the first and second components) is at most 1*10.sup.7 mPa.Math.s, or at most 8*10.sup.6 mPa.Math.s, or at most 6*10.sup.6 mPa.Math.s, or at most 4*10.sup.6 mPa.Math.s. Inventive concept 126. The method of any preceding inventive concept wherein the provided first and second aqueous ink components collectively provide the following property: a dry ink film dynamic viscosity μ.sub.g.sup.dry-film([5:1 2.sup.nd component:1.sup.st component], 110° C.) of a 5:1 weight-ratio of the first and second components) is at most 1*10.sup.7 mPa.Math.s, or at most 8*10.sup.6 mPa.Math.s, or more typically at most 6*10.sup.6 mPa.Math.s or at most 5*10.sup.6 mPa.Math.s or at most 4*10.sup.6 mPa.Math.s. Inventive concept 127. The method of any preceding inventive concept wherein the provided first and second aqueous ink components collectively provide the following property: a dry ink film dynamic viscosity μ.sub.g.sup.dry-film([5:1 2.sup.nd component:1.sup.st component], 105° C.) of a 5:1 weight-ratio of the first and second components is at most 2*10.sup.7 mPa.Math.s, at most 1*10.sup.7 mPa.Math.s, at most 8*10.sup.6 mPa.Math.s, or at most 6*10.sup.6 mPa.Math.s. Inventive concept 128. The method of any preceding inventive concept, wherein the provided first and second aqueous ink components collectively provide the following property: a dry ink film dynamic viscosity μ.sub.g.sup.dry-film([5:1 2.sup.nd component:1.sup.st component], 100° C.) of a 5:1 weight-ratio of the first and second components) is at most 2*10.sup.7 mPa.Math.s, at most 1*10.sup.7 mPa.Math.s, at most 8*10.sup.6 mPa.Math.s, or at most 6*10.sup.6 mPa.Math.s. Inventive concept 129. The method of any preceding inventive concept, wherein the provided first and second aqueous ink components collectively provide the following property: a dry ink film dynamic viscosity μ.sub.g.sup.dry-film([5:1 2.sup.nd component:1.sup.st component], 95° C.) of a 5:1 weight-ratio of the first and second is at most 2*10.sup.7 mPa.Math.s, at most 1*10.sup.7 mPa.Math.s, or at most 8*10.sup.6 mPa.Math.s, or at most 6*10.sup.6 mPa.Math.s. Inventive concept 130. The method of any preceding inventive concept, wherein the provided first and second aqueous ink components collectively provide the following property: a dry ink film dynamic viscosity μ.sub.g.sup.dry-film([5:1 2.sup.nd component:1.sup.st component], 90° C.) of a 5:1 weight-ratio of the first and second components is at most 1*10.sup.7 mPa.Math.s, at most 1.2**10.sup.7 mPa.Math.s or more typically at most 1*10.sup.7 mPa.Math.s, or at most 8*10.sup.6 mPa.Math.s. Inventive concept 131. The method of any preceding inventive concept, wherein immediately upon application of the covering wet volume of the first component to the ITM surface, a thickness of the covering wet volume is at least 6 μm or at least 8 μm or at least 10 μm or at least 12 μm. Inventive concept 132. The method of any preceding inventive concept, wherein immediately upon application of the covering wet volume of the first component to the ITM surface, a thickness of the covering wet volume is at least 8 μm or at least 10 μm or at least 12 μm. Inventive concept 133. The method of any preceding inventive concept, wherein the first ink component is delivered to the ITM surface when the ITM surface is in-motion at a velocity of at least 1 meters/second or at least 1.5 meters/second or at least 2 meters/second. Inventive concept 134. The method of any preceding inventive concept, wherein the droplets of the second ink component are deposited to onto the partially-dried layer of the first component when the ITM surface is in-motion at a velocity of at least 1 meters/second or at least 1.5 meters/second or at least 2 meters/second. Inventive concept 135. The method of any preceding inventive concept, wherein the method is performed so that a ratio between (i) a thickness of a partially-dried layer of the first component when the droplets of the second aqueous ink component impact the partially-dried layer of the first ink component in step (d) and (ii) a thickness of the covering wet volume of the first component immediately upon application of the covering wet volume of the first component on the ITM surface is at most 0.6 or at most 0.5 or at most 0.4. Inventive concept 136. The method of any preceding inventive concept, wherein the method is performed so that a ratio between (i) a thickness of a partially-dried layer of the first component when the droplets of the second aqueous ink component impact the partially-dried layer of the first ink component in step (d) and (ii) a thickness of the covering wet volume of the first component immediately upon application of the covering wet volume of the first component on the ITM surface is at least 0.25 or at least 0.3 or at least 0.35. Inventive concept 137. The method of any preceding inventive concept wherein within the provided second aqueous ink component comprises nanoparticles as a primary colorant of the second aqueous ink component. Inventive concept 138. The method of any preceding inventive concept, wherein immediately before impact between the droplets of the second ink component and the layer of the first ink component, a thickness of the layer of first ink component is at least 1 mm or at least 1.5 μm or at least 2 μm or at least 3 μm or at least 4 μm. Inventive concept 139. The method of any preceding inventive concept, wherein the transfer temperature T.sub.TRANSFER is at least 60° C., or at least 65° C., at least 70° C., or at least 75° C., at least 80° C., or at least 85° C., or at least 90° C., or at least 95° C., or at least 100° C., or at least 105° C., or at least 110° C., or at least 115° C. Inventive concept 140. The method of any preceding inventive concept, wherein the transfer temperature T.sub.TRANSFER is at most 65° C., or at most 70° C., or at most 75° C., or at most 80° C., or at most 85° C., or at most 90° C., or at most 95° C., or at most 100° C., or at most 105° C., or at most 110° C., or at most 115° C. Inventive concept 141. The method of any preceding inventive concept, wherein the transfer temperature T.sub.TRANSFER is at least 60° C. and at most 115° C. Inventive concept 142. The method of any one of inventive concepts 1-138, wherein the transfer temperature T.sub.TRANSFER is between 65° C. and 70° C. Inventive concept 143. The method of any one of inventive concepts 1-138, wherein the transfer temperature T.sub.TRANSFER is between 70° C. and 75° C. Inventive concept 144. The method of any one of inventive concepts 1-138, wherein the transfer temperature T.sub.TRANSFER is between 75° C. and 80° C. Inventive concept 145. The method of any one of inventive concepts 1-138, wherein the transfer temperature T.sub.TRANSFER is between 80° C. and 85° C. Inventive concept 146. The method of any one of inventive concepts 1-138, wherein the transfer temperature T.sub.TRANSFER is between 85° C. and 90° C. Inventive concept 147. The method of any one of inventive concepts 1-138, wherein the transfer temperature T.sub.TRANSFER is between 90° C. and 95° C. Inventive concept 148. The method of any one of inventive concepts 1-138, wherein the transfer temperature T.sub.TRANSFER is between 90° C. and 100° C. Inventive concept 149. The method of any one of inventive concepts 1-138, wherein the transfer temperature T.sub.TRANSFER is between 95° C. and 100° C. Inventive concept 150. The method of any one of inventive concepts 1-138, wherein the transfer temperature T.sub.TRANSFER is between 95° C. and 105° C. Inventive concept 151. The method of any one of inventive concepts 1-138, wherein the transfer temperature T.sub.TRANSFER is between 100° C. and 105° C. Inventive concept 152. The method of any one of inventive concepts 1-138, wherein the transfer temperature T.sub.TRANSFER is between 100° C. and 110° C. Inventive concept 153. The method of any one of inventive concepts 1-138, wherein the transfer temperature T.sub.TRANSFER is between 105° C. and 110° C. Inventive concept 154. The method of any one of inventive concepts 1-138, wherein the transfer temperature T.sub.TRANSFER is between 105° C. and 115° C. Inventive concept 155. The method of any one of inventive concepts 1-138, wherein the transfer temperature T.sub.TRANSFER is between 110° C. and 115° C. Inventive concept 156. The method of any one of inventive concepts 1-138, wherein the transfer temperature T.sub.TRANSFER is above 115° C. Inventive concept 157. The method of any one of inventive concepts 1-138, wherein a dry film glass transition temperature T.sub.g.sup.dry_film([2.sup.nd component]) of the second ink component exceeds by P° C. the transfer temperature T.sub.TRANSFER; and a dry film glass transition temperature T.sub.g.sup.dry_film([5:1 2.sup.nd component:1.sup.st component]) of a 5:1 weight-ratio of the first and second components is less than the transfer temperature T.sub.TRANSFER, by Q° C. Inventive concept 158. The method of inventive concept 157 wherein a value of P is at least 5, or at least 10, or at least 12, or at least 15, or at least 20 or at least 30, or at least 40. Inventive concept 159. The method of any one of inventive concepts 157-158 wherein a value of Q is at least 5, or at least 10, or at least 12, or at least 15, or at least 20 or at least 30, or at least 40. Inventive concept 160. The method of any preceding inventive concept, wherein during step (d), the layer of the first component blocks the colorant particles of the second component from directly contacting the ITM surface so that, at a time of the transfer, a colorant-particle-free layer is present on the ITM surface below the colorant particles of the second component. Inventive concept 161. The method of any preceding inventive concept, wherein during step (d) and while the layer of first component comprises at least 10% wt/wt water or at least 20% wt/wt water, the layer of the first component blocks the colorant particles of the second component from directly contacting the ITM surface so that, at a time of the transfer, a colorant-particle-free layer is present on the ITM surface below the colorant particles of the second component. Inventive concept 162. A digital printing system comprising: a. a rotatable intermediate transfer member (ITM); b. drying apparatus for effecting heating material disposed on the ITM; c. respective reservoirs of first and second aqueous ink components, the first aqueous ink component optionally being transparent, the second aqueous ink component comprising colorant particles; d. a first liquid delivery station at which the first reservoir is disposed, the first liquid delivery station being configured to deliver a quantity of the first ink component to a target surface of the ITM, to cover a portion of the target surface with a wet volume of the first ink component; and e. a second liquid delivery station at which the second reservoir is disposed, the second liquid delivery station configured to digitally deposit droplets of the second ink component onto the volume of the first ink component after downstream transport on the rotatable ITM, to form a wet, colored ink-image, wherein the system is controlled so that: i. the wet volume of the first ink component is only partial dried after covering the portion of the surface and before impact thereon of the droplets of the second ink component at the second liquid delivery station so that, the first ink component is sufficiently moist and permeable such that some or all the colorant particles of the second ink component penetrate into the partially-dried layer of the first ink component; ii. after formation of the ink-image at the second liquid delivery station, the ink-image is at least partially dried to produce a dried, tacky ink film, and wherein the system further comprises a transfer station at which the dried ink film is transferred from the ITM to a printing substrate. Inventive concept 163. A digital printing system comprising: a. a rotatable intermediate transfer member (ITM); b. drying apparatus for effecting heating material disposed on the ITM; c. respective reservoirs of first and second aqueous ink components, the first aqueous ink component optionally being transparent, the second aqueous ink component comprising colorant particles; d. a first liquid delivery station at which the first reservoir is disposed, the first liquid delivery station being configured to deliver a quantity of the first ink component to a target surface of the ITM, to cover a portion of the target surface with a wet volume of the first ink component; and e. a second liquid delivery station at which the second reservoir is disposed, the second liquid delivery station configured to digitally deposit droplets of the second ink component onto the volume of the first ink component after downstream transport on the rotatable ITM, to form a wet, colored ink-image, wherein the system is controlled so that: i. the wet volume of the first ink component is only partial dried after covering the portion of the surface and before impact thereon of the droplets of the second ink component at the second liquid delivery station so that, upon impact, the first ink component is sufficiently moist and permeable such that some or all the colorant particles of the second ink component penetrate into the partially-dried layer of the first ink component; and ii. the wet, colored image is at least partially dried on the ITM by the drying apparatus; wherein the system further comprises a transfer station at which the at least partially dried ink-image is transferred from the ITM to printing substrate. Inventive concept 164. The system of any one of inventive concepts 162-163 wherein the drying apparatus is a heating-drying apparatus for effecting both heating and drying of material disposed on the ITM. Inventive concept 165. The system of inventive concept 164 wherein the heating-drying apparatus sufficiently heats the partially dried ink-image so that it is tacky upon transfer from the ITM to the substrate at the transfer station. Inventive concept 166. The system of any of inventive concepts 162-165 wherein (i) the system is controlled so that the at least partial drying produces a dried, tacky ink-image-bearing residue film; and (ii) the dried, tacky ink-image-bearing residue film is transferred from the ITM to the printing substrate at the transfer station. Inventive concept 167. The system of any one of inventive concepts 86-162-166 wherein: i. the first liquid delivery station comprises a first print-bar array of one or more print bar(s), the first print-bar array configured to deliver at least a portion of the quantity of the first liquid ink component to the target surface of the ITM by droplet deposition; ii. the second liquid delivery station comprises a second print-bar array of one or more print bar(s) located downstream of the first print print-bar array, the second print-bar array configured to at digitally deposit at least some of the droplets of the second ink component. Inventive concept 168. The system of any one of inventive concepts—162-166 wherein a series of print-bars are disposed over the ITM such that: i. a first print-bar of the series of print-bars belongs to the first liquid delivery station and deposits the quantity of the first liquid component to the target surface by droplet deposition; ii. all other print-bars of the series of print-bars collectively belong to the second liquid Inventive concept 169. The system of any one of inventive concepts 162-168, wherein the first liquid delivery station comprises one or more ink-jet print heads. Inventive concept 170. The system of any one of inventive concepts 162-169, wherein the first liquid delivery station comprises at least one of (i.e. any combination of) a coater, spray assembly, a bath assembly, a thinning assembly and a doctor blade.
EXAMPLES
(134) Reference is now made to the following examples, which together with the above descriptions, illustrate the invention in a non-limiting fashion.
(135) List of Materials Used:
(136) TABLE-US-00001 Ingredient Supplier Function Chemical Name/Description Joncryl ® 90 BASF binder Manufacturer Description: styrene-acrylic copolymer emulsion, 44% solids MW >200,000 Tg 110° C. (DSC) T.sub.MFFT >85° C. Joncryl ® 538 BASF binder Manufacturer Description: acrylic polymer emulsion, 46.5% solids MW >200,000 Tg 64° C. (DSC) T.sub.MFFT 60° C. Joncryl ® 8085 BASF binder Styrene-acrylic copolymer emulsion, 42.5% solids Tg 57° C. Tween ® 20 Sigma- Plasticizing agent PEG-20 sorbitan monolaurate Aldrich Tween ® 40 Sigma- Plasticizing agent PEG-20 sorbitan monopalmitate Aldrich Tween ® 65 Sigma- Plasticizing agent PEG-20 sorbitan tristearate Aldrich Tween ® 80 Sigma- Plasticizing agent PEG-20 sorbitan monooleate Aldrich Tween ® 60 Sigma- Plasticizing agent PEG-20 sorbitan monolstearate Aldrich Tego ® Wet 240 Evonik surfactant Polyether siloxane copolymer Tego ® Twin 4100 Evonik surfactant Siloxane-based gemini surfactant Byk ® 333 BYK ® Surface energy Polyether-modified modifier polydimethylsiloxane AMP95 ® Angus pH modifier 2-Amino-2-methyl-1-propanol Mogul ® L Cabot colorant Black pigment Triethanolamine Sigma- pH modifier (TEA) Aldrich Joncryl ® 142 BASF thickener Acrylic colloidal emulsion 40% solids Acrysol ® RM-2020E Dow Non-ionic urethane Hydrophobically modified polyethylene rheology modifier oxide urethane 20% solids Viscosity: 2500-3800 mPa .Math. s Rheovis ® PE1330 BASF Non-ionic urethane 30% solids rheology modifier Viscosity: 4500 mPa .Math. s at 23° C. Rheovis ® AS1125 BASF Rheology modifier 25% solids (Acrylic thickener) Viscosity equal to or less than 1300 mPa .Math. s at 23° C. Ganex ® P-904 LC Ashland Rheology modifier alkylated polyvinyl pyrrolidones Basacid ® Blau 762 BASF Colorant Blue Dye ~20% dye Efka ®4585 BASF Dispersing agent Acrylic block copolymer 50% solids Tego ®280 Evonik Substrate wetting Polyether siloxane polymer and anti-cratering additive Joncryl ®8078 BASF binder Acrylic resin solution, 32% solids Tg = 101° C. Byk ® 024 BYK ® Defoamer Polysiloxanes and hydrophobic solids in polyglycol DMEA Sigma- pH modifier Dimethyl-ethanolamine Aldrich
Release Layer:
(137) TABLE-US-00002 CAS Ingredient Supplier Number Description DMS-V35 Resin Gelest 68083-19-2 Vinyl terminated polydimethyl siloxane Viscosity 5,000 mPa .Math. s MW ~49,500 Vinyl ~0.018-0.05 mmol/g VQM-146 Resin Gelest 68584-83-8 20-25% Vinyl resin in DMS V46 Viscosity 50,000-60,000 mPa .Math. s Vinyl ~0.18-0.23 mmol/g Inhibitor 600 Evonik 204-070-5 Mix of divinylpolydimethylsiloxane and Cure Retardant 2-methylbut-3-yn-2-ol Viscosity 900 mPa .Math. s Vinyl 0.11 mmol/g SIP6831.2 Catalyst Gelest 68478-92-2 Platinum divinyltetramethyldisiloxane Platinum 2.1-2.4% Polymer RV 5000 Evonik Vinyl-functional polydimethyl siloxanes (XPRV 5000) Viscosity 3000 mPa .Math. s Resin Vinyl 0.4 mmol/g Crosslinker 100 Evonik Polydimethyl siloxanes including SiH Crosslinker groups in the polymer chain Hydride 7.8 mmol/g HMS-301 Gelest 68037-59-2 Poly(dimethylsiloxane-co-methyl- Crosslinker hydrosiloxane), trimethylsilyl terminated Hydride 4.2 mmol/g Silsurf A010-D-UP Siltech 134180-76-0 polyether siloxane copolymer Additive SilGrip SR 545 Momentive 56275-01-5 Silicone-based resin containing “MQ” Functional MQ resin groups Viscosity 11 mPa .Math. s Skyroll SH 92 SKC Inc. NR Anti-static polyester film Skyroll SH 76 SKC Inc. NR Untreated polyester film
Example 1
Preparation of 1.SUP.st .Ink Component
(138) The water, humectant, and any pH modifier were added and stirred in a mixing vessel. Mixing was continued as the other components were added. Any plasticizer was then added, followed by the binder/resin, followed by the surfactants.
Example 2
(139) An exemplary 1.sup.st ink component of the present invention had the following composition (all figures provided in weight-percent):
(140) 40% Joncryl® 538
(141) 5% Tween® 80
(142) 3.3% Tego® Wet 240
(143) 0.3% wt Byk-333
(144) 0.2% AMP 95®
(145) 8% propylene glycol
(146) Balance: water
(147) The composition was formulated according to the procedure provided in EXAMPLE 1. The pH was 8.0.
Example 3
(148) Another exemplary 1.sup.st ink component of the present invention had the following composition:
(149) 15% Joncryl® 538
(150) 2% Tween® 40
(151) 2.5% Tego® Wet 240
(152) 0.3% wt Bykc®-333
(153) 0.2% AMP 95®
(154) 32.5% propylene glycol
(155) Balance: water
(156) The composition was formulated according to the procedure provided in EXAMPLE 1.
Example 4
(157) Another exemplary 1.sup.st ink component of the present invention had the following composition:
(158) 40% Joncryl® 538
(159) 3.5% Tween® 60
(160) 3.5% Tego® Twin 4100
(161) 0.2% AMP 95® ®
(162) 8.1% propylene glycol
(163) Balance: water
(164) The composition was formulated according to the procedure provided in EXAMPLE 1.
Example 4A
(165) Another exemplary 1.sup.st ink component had the following composition:
(166) 22% Joncryl® 90
(167) 12.2% Joncryl® 8085
(168) 3.5% Tween® 20
(169) 2.5% Tego® Wet 240
(170) 0.2% AMP 95®
(171) 18% propylene glycol
(172) Balance: water
(173) The composition was formulated according to the procedure provided in EXAMPLE 1.
Example 4B
(174) Another exemplary 1.sup.st ink component had the following composition:
(175) 10% Joncryl® 90
(176) 22% Joncryl® 8085
(177) 3.5% Tween® 60
(178) 2.5% Tego® Wet 240
(179) 0.2% AMP 95®
(180) 18% propylene glycol
(181) Balance: water
(182) The composition was formulated according to the procedure provided in EXAMPLE 1. The pH was 7.9.
Example 5
Preparation of 2.SUP.nd .Ink Component
(183) A pigment concentrate, containing pigment, water and dispersant, is dispersed using a high shear mixer. The product obtained is then milled in a bead mill. The progress of the milling was monitored and controlled on the basis of particle size measurements (for example, Malvern® and Nanosizer® instruments). The milling was curtailed when the average particle size (d50) reached 70 to 100 nm.
Example 6
Dynamic Viscosity Measurements
(184) The viscosity of the ink components described herein were measured at 25° C. using a viscometer (DV II+Pro by Brookfield). Viscosities were typically in the range of about 2 mPa.Math.s to 100 mPa.Math.s.
Example 7
Surface Tension Measurements
(185) The surface tension of the ink components was measured using a standard liquid tensiometer (EasyDyne by Krüss) and was generally in the range of approximately 20 to 40 mN/m.
Example 8
Opacity Measurement Procedure
(186) The opacity of the 1.sup.st ink component was measured using an i1Pro spectrophotometer manufactured by X-Rite. The measurements were made on a Form 2A Opacity card manufactured by Leneta Company, Inc.
(187) The opacity (by contrast ratio measurement) of each ink sample was determined according to the formula:
Opacity=Yb*100/Yw wherein: Yb is the measurement on the black half on the card, and Yw is the measurement on the white half on the card; and wherein Yb and Yw are each the average of 3 measurements at different places on the respective area. The lower the opacity, the higher the transparency. The evaluation is generally performed in accordance with International Standard ISO 6504-3; the samples were jetted onto an ITM and the dry film was then transferred to the Leneta opacity card.
Example 9
Opacity Results
(188) In the absence of a clear layer, the “reference” opacity card yields an opacity of approximately 0.87.
(189) For transparent layers of the present invention disposed on top of the opacity card, the opacity ranged from 0.87 to 1.17. More generally, the opacity of transparent layers of the present invention disposed on top of the opacity card falls within a range of 0.87 to 4, 0.87 to 3, 0.87 to 2.5, 0.87 to 2, 0.87 to 1.5, 0.87 to 1.2, 0.9 to 4, 0.9 to 3, 0.9 to 2.5, 0.9 to 1.5, or 0.9 to 1.2.
Example 10
(190) A millbase containing black pigment in a dispersant, formulated according to the method of EXAMPLE 5, had the following composition:
(191) TABLE-US-00003 Millbase Component % wt. Deionized water 50.0% Bykjet ® 9152 25.0% Mogul ® L 25.0%
Example 11
(192) An exemplary 2.sup.nd ink component of the present invention, formulated in accordance with the procedure provided in EXAMPLE 5, and utilizing the millbase from EXAMPLE 10, had the following composition:
(193) TABLE-US-00004 Ink Component Wt. % Water 36.2 TEA 0.3 Propylene Glycol 45.0 Glycerin 6.0 Black Millbase 12.0 Tego ® Wet 240 0.5
(194) The total non-volatile content was 12.5%. The ink had the following measured properties:
(195) TABLE-US-00005 Parameter Measured Result pHpH 9.5 Surface Tension (mN/m) 26 Viscosity (mPa .Math. s) 6.5
Example 12
(196) Another exemplary 2.sup.nd ink component of the present invention, formulated in accordance with the procedure provided in EXAMPLE 5, and utilizing the millbase from EXAMPLE 10, had the following composition:
(197) TABLE-US-00006 Component Wt. % AMP 95 ® 0.5 Propylene Glycol 23.0 1,2-Hexanediol 3.0 Sorbitol 3.0 Joncryl ®142 E (40% NVS) 3.8 Black Millbase 12.0 Tego ® Wet 240 1.0 Water Balance
(198) The total non-volatile content was 11.5%. The ink had the following measured properties:
(199) TABLE-US-00007 Parameter Measured Result pH 9.2 Surface Tension (mN/m) 25.2 Viscosity (mPa .Math. s) 7
Example 12A
(200) A millbase containing black pigment in a dispersant, formulated according to the method of EXAMPLE 5, had the following composition:
(201) TABLE-US-00008 Millbase Component % wt. Deionized water 45% Efka ® 4585 30% Mogul ® L 25%
The solids content was approximately 40%, by weight.
Examples 13-20
(202) Exemplary 2.sup.nd ink components of the present invention, formulated in accordance with the procedure provided in EXAMPLE 5, and utilizing the millbase from EXAMPLE 12A, had the following compositions:
(203) TABLE-US-00009 Ink Component -- EXAMPLE 13 Wt. % AMP95 0.6 Propylene Glycol 23.0 Tween ® 20 3.0 Joncryl ® 142 3.75 Mogul ® L 3.0 Efka ® 4585 3.6 Tego ® Wet 240 0.5 Tego ® Wet 280 0.5 Water Balance Non-Volatile Solids 10.3%
(204) TABLE-US-00010 Ink Component -- EXAMPLE 14 Wt. % AMP 95 ® 0.6 Propylene Glycol 24.0 Tween ® 20 3.0 Mogul ® L 3.0 Efka ® 4585 3.6 Tego ® Wet 240 0.5 Tego ® Wet 280 0.5 Water Balance Non-Volatile Solids 8.8%
(205) TABLE-US-00011 Ink Component -- EXAMPLE 15 Wt. % AMP 95 ® 0.2 Propylene Glycol 20.0 Tween ® 20 3.0 Acrysol ® 2020E 4.0 Mogul ® L 3.0 Efka ® 4585 3.6 Tego ® Wet 240 0.5 Tego ® Wet 280 0.5 Water Balance Non-Volatile Solids 9.6%
(206) TABLE-US-00012 Ink Component -- EXAMPLE 16 Wt. % AMP 95 ® 0.2 Propylene Glycol 20.0 Tween ® 20 3.0 Rheovis ® AS1125 0.8 Mogul ® L 3.0 Efka ® 4585 1.8 Tego ® Wet 240 0.5 Tego ® Wet 280 0.5 Water Balance Non-Volatile Solids 9.0%
This formulation exhibited poor stability, which may be attributable to the presence of Rheovis® AS1125.
(207) TABLE-US-00013 Ink Component -- -- EXAMPLE 17 Wt. % AMP 95 ® 0.2 Propylene Glycol 20.0 Tween ® 20 3.0 Rheovis ® PE1330 2.67 Mogul ® L 3.0 Efka ® 4585 3.6 Tego ® Wet 240 0.5 Tego ® Wet 280 0.5 Water Balance Non-Volatile Solids 9.6%
(208) TABLE-US-00014 Ink Component -- EXAMPLE 18 Wt. % AMP 95 ® 0.5 Propylene Glycol 22.4 Tween ® 20 3.0 Rheovis ® AS1125 0.16 Joncryl ® 142 3.0 Mogul ® L 3.0 Efka ® 4585 3.6 Tego ® Wet 240 0.5 Tego ® Wet 280 0.5 Water Balance Non-Volatile Solids 10.04%
This formulation exhibited poor stability, which may be attributable to the presence of Rheovis® AS1125.
(209) TABLE-US-00015 Ink Component -- EXAMPLE 19 Wt. % AMP 95 ® 0.2 Propylene Glycol 23.0 Tween ® 20 3.0 Ganex ® P904LC 2.0 Mogul ® L 3.0 Efka ® 4585 3.6 Tego ® Wet 240 0.5 Tego ® Wet 280 0.5 Water Balance Non-Volatile Solids 10.8%
(210) TABLE-US-00016 Ink Component -- EXAMPLE 20 Wt. % Triethanolamine 0.1 Propylene Glycol 46.0 Glycerin 6.0 Basacid ® Blau 762 12.5 Tego ® Wet 240 0.1 Water Balance
Example 20A
(211) A millbase containing blue pigment in a dispersant, formulated according to the method of
(212) EXAMPLE 5, had the following composition:
(213) TABLE-US-00017 Millbase Component % wt. Deionized water 40% Efka ® 4585 35% PV FAST BLUE BG-NIP 25%
The solids content was approximately 42.5%, by weight.
Example 21
(214) Exemplary 2.sup.nd ink components of the present invention, formulated in accordance with the procedure provided in EXAMPLE 5, and utilizing the millbase from EXAMPLE 12A, had the following compositions:
(215) TABLE-US-00018 Ink Component Wt. % AMP 95 ® 0.30 Propylene Glycol 24.34 Xylitol 3.3 Joncryl 8078 4.69 MILLBASE EXAMPLE 20A 7.60 Efka ® 4585 4.0 Tego ® Twin 4100 0.6 Water Balance
Example 22
(216) The viscosity of various exemplary 1.sup.st ink components, measured at 25° C., is provided below (all values in mPa.Math.s): Example 2=6.5 Example 3=6.3 Example 4A=5.4 Example 4B=6.5
Example 23
(217) The surface tension of the following exemplary 1.sup.st ink components, measured at 25° C., is provided below (all values in mN/m): Example 2=25.3 Example 4B=23.3
More generally, the surface tension of the 1.sup.st ink component of the present invention, measured at 25° C., lies within the range of 20-35 mN/m, 20-32 mN/m, 22-28 mN/m, or 22-26 mN/m.
Example 24
Ink Drying Procedure
(218) 20 grams of sample were placed in 2 aluminum dishes (90 mm diameter). The dishes were placed in an oven set to 90° C., and dried for 48 hours minimum. The dishes were weighed after 24 and 48 hours. If the weights differed by more than 1%, an additional 24 hours heating was performed, and the dishes weighed again. This was repeated until the up to 1% weight differential criterion was met. With respect to the samples provided herein, none required more than 48 hours heating.
Example 25
Resolubility Characterization
(219) Resolubility was determined as follows: 1 gram of ink was placed in a polypropylene beaker having a capacity of about 100 ml, and dried in an oven at 40° C. for 24 hours. Subsequently, 2 grams of fresh ink were introduced to the beaker, and the contents were mixed by swirling by hand for up to ten minutes. If no film residue remained on the bottom of the beaker, and/or the mixture passed through a 0.7 GF syringe filter without clogging, the ink is considered to be resoluble.
Example 26
Resolubility Results
(220) The 2.sup.nd ink components of EXAMPLES 14, 15, 17, 18, and 20 were evaluated for resolubility according to the procedure provided in EXAMPLE 25. No film residue remained on the bottom of the beaker, and the mixture passed through the syringe filter without clogging. Thus, all of these examples exhibited resolubility.
Examples 27-28
(221) A 1:1 (wt.-wt.) mixture (“EXAMPLE 27”) of the 1st ink component of EXAMPLE 2 and the 2.sup.nd ink component of EXAMPLE 21 was prepared by mixing at room temperature. Similarly, a 2.5:1 (wt.-wt.) mixture was prepared (“EXAMPLE 28”).
Example 29
Measurement of Glass Transition Temperature
(222) Samples were placed in a Q2000 Differential Scanning calorimeter (TA Instruments) and DSC measurements were carried out. The DSC was first operated in a modulated operation mode, in order to detect any presence of minor Tg peaks. This mode had a temperature amplitude of 1.27° C., a period of 60 seconds, and a heating rate of 2° C. per minute. In the modulated operation, no such small peaks were observed. This allowed a more relaxed procedure (“standard mode of operation”), without modulation, and having a scanning rate of 8° C. per minute.
(223) The samples were first heated to and maintained at 120° C. for 60 seconds to allow thermal equilibration, prior to initiating the scanning mode.
Examples 30-33: Glass Transition Temperature Results
Example 30
(224) The Glass Transition Temperature (Tg) of a dried residue of the cyan-pigmented 2.sup.nd ink component of EXAMPLE 21 was evaluated according to the procedure of EXAMPLE 29. The residue was obtained according to the drying procedure of EXAMPLE 24. No Tg was observed up to a temperature of about 120° C., only a melting point.
Examples 31-33
(225) Following the drying procedure of EXAMPLE 24, the Tg of the 1.sup.st ink component of EXAMPLE 2, as well as the mixtures of EXAMPLES 27-28, were evaluated according to the procedure of EXAMPLE 29. The three samples exhibited similar Glass Transition Temperatures—Tg=56±2° C. Thus, the softness and transferability of the 2.sup.nd ink component of EXAMPLE 21 was appreciably enhanced by mixing in a 2.5:1 and even a 1:1 weight ratio of the 1.sup.st ink component of EXAMPLE 2.
Example 34
Thermo-Rheological Characterization of Dry Ink Films
(226) Viscosity characterization of dry ink films were performed, as a function of temperature, using a Discovery HR-2 rheometer (TA Instruments). Following the drying procedure of EXAMPLE 24, a strain sweep of the dry ink films was first performed at a frequency of 1 Hz, to demonstrate that the behavior of the materials being characterized was well within the linear visco-elastic range. Consequently, subsequent viscosity characterizations were performed at 1 Hz.
(227) Initially, the dried ink residue was heated to 120° C., after which any excess material was removed. After maintaining the temperature at 120° C. for 60 seconds, the viscosity was measured twice (at a 60-second interval), and the temperature was then reduced to 90° C. and maintained for 60 seconds. The viscosity was measured twice (at a 60-second interval) at 90° C., and the temperature was then reduced to 70° C. and maintained for 60 seconds. Following two viscosity measurements at 70° C. (at a 60-second interval), the temperature was reduced to 50° C., and after maintaining for 60 seconds, the two final viscosity measurements were performed at 50° C. (at a 60-second interval). The viscosity results were obtained by averaging each of the two measurements.
Examples 35-38
Thermo-Rheological Characterization—Results
(228) Using the procedure of EXAMPLE 34, the 1.sup.st ink component of EXAMPLE 2, the cyan-pigmented 2.sup.nd ink component of EXAMPLE 21, and the mixtures of EXAMPLES 27-28, were subjected to thermo-rheological characterization. The viscosity results are provided in the following table:
(229) TABLE-US-00019 Viscosity [mPa .Math. s] vs. Temp Sample 120° C. 90° C. 70° C. 50° C. EXAMPLE 2 3.04E+06 7.48E+06 1.77E+07 5.35E+08 EXAMPLE 21 1.12E+07 4.09E+07 4.50E+07 4.60E+07 EXAMPLE 27 2.38E+06 7.02E+06 2.34E+07 6.23E+08 EXAMPLE 28 2.15E+06 5.55E+06 1.78E+07 3.64E+08
Example 39
(230) The ITM release layer of EXAMPLE 39 had the following composition (wt./wt.):
(231) TABLE-US-00020 Name Parts DMS-V35 70 XPRV-5000 30 VQM-146 40 Inhibitor 600 5 SIP6831.2 0.1 Crosslinker 12 HMS-301
The release layer was prepared substantially as described in the following preparation procedure, provided below.
Blanket Preparation Procedure (for Release Layers Cured Against a Carrier Surface)
(232) All components of the release layer formulation were thoroughly mixed together. The desired thickness of the incipient release layer was coated on a PET sheet, using a rod/knife (other coating methods may also be used), followed by curing for 3 minutes at 150° C. Subsequently, Siloprene LSR 2530 was coated on top of the release layer, using a knife, to achieve a desired thickness. Curing was then performed at 150° C. for 3 minutes. An additional layer of Siloprene LSR 2530 was then coated on top of the previous (cured) silicone layer, and fiberglass fabric was incorporated into this wet, fresh layer such that wet silicone penetrated into the fabric structure. Curing was then performed at 150° C. for 3 minutes. A final layer of Siloprene LSR 2530 was then coated onto the fiberglass fabric and, once again, curing was performed at 150° C. for 3 minutes. The integral blanket structure was then cooled to room temperature and the PET was removed.
Example 40
(233) The ITM release layer of EXAMPLE 40 has the following composition:
(234) TABLE-US-00021 Component Name Parts DMS-V35 70 XPRV-5000 30 VQM-146 40 Inhibitor 600 5 SIP6831.2 0.1 Crosslinker HMS-301 12 Silsurf A010-D-UP 5
The blanket was prepared substantially as described in Example 39.
Example 41
(235) The ITM release layer of Example 41 has the following composition:
(236) TABLE-US-00022 Component Name Parts DMS-V35 70 XPRV-5000 30 VQM-146 40 Inhibitor 600 5 SIP6831.2 0.1 Crosslinker 100 6.5 Silsurf A010-D-UP 5
The blanket was prepared substantially as described in Example 39.
Example 42
(237) The ITM release layer of EXAMPLE 42 has the following composition:
(238) TABLE-US-00023 Component Name Parts DMS-V35 100 VQM-146 40 Inhibitor 600 3 SIP6831.2 0.1 Crosslinker HMS-301 5
The blanket was prepared substantially as described in EXAMPLE 39.
Example 43
(239) The ITM release layer of EXAMPLE 43 was prepared from Silopren® LSR 2530 (Momentive Performance Materials Inc., Waterford, N.Y.), a two-component liquid silicone rubber, in which the two components are mixed at a 1:1 ratio. The blanket was prepared substantially as described in EXAMPLE 39.
Example 44
(240) The ITM release layer of EXAMPLE 44 has a composition that is substantially identical to that of EXAMPLE 4, but includes SR545 (Momentive Performance Materials Inc., Waterford, N.Y.), a commercially available silicone-based resin containing polar groups. The polar groups are of the “MQ” type, where “M” represents Me.sub.3SiO and “Q” represents SiO.sub.4. The full composition is provided below:
(241) TABLE-US-00024 Component Name Parts DMS-V35 100 VQM-146 40 SR545 5 Inhibitor 600 3 SIP6831.2 0.1 Crosslinker HMS-301 5
The blanket was prepared substantially as described in EXAMPLE 39.
Example 45
(242) The ITM release layer of EXAMPLE 45 has a composition that is substantially identical to that of EXAMPLE 44, but includes polymer RV 5000, which includes vinyl-functional polydimethyl siloxanes having a high density of vinyl groups, as described hereinabove. The full composition is provided below:
(243) TABLE-US-00025 Component Name Parts DMS-V35 70 RV 5000 30 VQM-146 40 Inhibitor 600 5 SIP6831.2 0.1 Crosslinker HMS-301 12 SR545 5
The blanket was prepared substantially as described in EXAMPLE 39.
Comparative Examples 39A-39F
(244) ITM release layers were prepared as “corresponding release layers” or “reference release layers” to the compositions of EXAMPLES 39-44, such that the corresponding release layers (designated Comparative Examples 39A-39F) had the identical compositions as Examples 39-44, respectively. However, during the curing of the release layer, the release layer surface (or “ink reception surface”) was exposed to air (“standard air curing”), according to a conventional preparation procedure, provided below.
(245) Comparative Blanket Preparation Procedure (for Release Layers Exposed to Air During Curing)
(246) A first layer of Siloprene LSR 2530 was coated on a PET sheet, using a rod/knife, followed by curing for 3 min at 150° C., to achieve the desired thickness. An additional layer of Siloprene LSR 2530 was then coated on top of the previous (cured) silicone layer, and fiberglass fabric was incorporated into this wet, fresh layer such that wet silicone penetrated into the fabric structure. Siloprene LSR 2530 was then coated on top of the fiberglass fabric, and curing ensued at 150° C. for 3 minutes. Prior to forming the incipient release layer, all components of the release layer formulation were thoroughly mixed together. The release layer was coated on top of cured Siloprene LSR 2530 to achieve the desired thickness, and was subsequently cured at 150° C. for 3 minutes, while the release layer surface was exposed to air.
Example 46
(247) Contact angles of drops of distilled water on release layer surfaces were measured using a dedicated Dataphysics OCA15 Pro contact angle-measuring device (Particle and Surface Sciences Pty. Ltd., Gosford, NSW, Australia). The procedure used for performing the Receding Contact Angle (RCA) and Advancing Contact Angle (ACA) measurements is a conventional technique elaborated by Dr. Roger P. Woodward (“Contact Angle Measurements Using the Drop Shape Method”, inter alia, www.firsttenangstroms.com/pdfdocs/CAPaper.pdf).
(248) The results for EXAMPLES 39-44 are provided below, along with the results for the release layers produced according to Comparative Examples 39A-39F.
(249) In virtually all cases, the release surfaces produced against the carrier surfaces exhibited lower Receding Contact Angles than the identical formulation, cured in air. More typically, the release surfaces produced against the carrier surfaces exhibited Receding Contact Angles that were lower by at least 5°, at least 7°, at least 10°, at least 12°, or at least 15°, or were lower within a range of 5°-300, 7°-300, 10°-300, 5°-250, 5°-22°, 7°-25°, or 10°-25°.
Example 47
(250) The release surfaces produced in EXAMPLES 39-44 and the respective release surfaces produced in Comparative Examples 39A-39F were aged at 160° C. for 2 hours, to simulate the aging of the release layer under extended operating conditions. Receding Contact Angles were measured, and the results are provided below:
(251) TABLE-US-00026 Release Surface Release Surface vs. PET vs. Air RCA RCA Comparative RCA RCA Release before after release before after formulation aging aging formulation aging aging Example 39 75° 80° Comparative 95° 95° Example 39A Example 40 45° 60° Comparative 65° 65° Example 39B Example 41 40° 50° Comparative 63° 65° Example 39C Example 42 65° 62° Comparative 79° 75° Example 39D Example 43 70° 74° Comparative 80° 80° Example 39E Example 44 56° 70° Comparative 74° 70° Example 39F
(252) With regard to the comparative examples, it is evident that the receding contact angle is substantially maintained after performing the aging process. With regard to inventive Examples 39-44, however, it is evident that the receding contact angle increases, typically by 4°-15°, after performing the aging process. Without wishing to be bound by theory, the inventors believe that the increase in contact angle in the inventive release layer structures may be attributed to a loss in hydrophilic behavior (or increased hydrophobic behavior) due to some change in the position of the polar groups (e.g., Si—O—Si) at the release layer surface.
Example 47
(253) The release layer produced in Example 2 was subjected to contact angle measurements. The receding contact angle was 45°. Significantly, the release layer surface of EXAMPLE 40, prepared against an anti-static PET carrier surface, displayed a receding contact angle that was about 50° less than the receding contact angle of the same composition prepared while exposed to air.
Example 48
(254) The carrier surface utilized in EXAMPLE 40 was subjected to contact angle measurements, to determine both the advancing contact angle and the receding contact angle. The advancing contact angle was 40°, while the receding contact angle was 20°. Significantly, the hydrophilic behavior of the carrier surfaces has been at least partially induced in the respective release surfaces: the formulation cured while exposed to air has an RCA of 65°; the same formulation, prepared against an antistatic PET surface, has an RCA of 45°; the anti-static PET carrier used displays an RCA of 20°. Thus, this release layer structure has a release surface whose hydrophilicity/hydrophobicity properties lie in between the properties of the same formulation, cured in air, and the carrier surface itself.
Example 49
(255) Release layer surface energies were calculated for ink reception surfaces of EXAMPLE 39, cured against an anti-static PET surface; and EXAMPLE 39, cured against an anti-static PET surface and then subjected to the standard aging procedure at 160° C., for 2 hours. These surfaces have the identical chemical formulation.
(256) For each of these examples, the total surface energy was calculated using the classic “harmonic mean” method (also known as the Owens-Wendt Surface Energy Model, see, by way of example, KRUSS Technical Note TN306e). The results are provided below:
(257) TABLE-US-00027 Release formulation Total Surface Energy J/m.sup.2 Example 39 -- Aged 22.6 Example 39 26.1
(258) EXAMPLE 39, when cured against an anti-static PET surface, exhibited a total surface energy of about 26 J/m.sup.2. After this formulation was subjected to the standard aging procedure, the total surface energy decreased from about 26 J/m.sup.2 to under 23 J/m.sup.2. This result would appear to corroborate the RCA results obtained for the various aged and un-aged materials of this exemplary formulation.
Example 50
(259) Release layer surface energies were calculated for ink reception surfaces of the following Examples: EXAMPLE 40, cured against an anti-static PET surface; and EXAMPLE 40—Aged, cured against an anti-static PET surface and then subjected to the standard aging procedure at 160° C., for 2 hours. These examples have the identical chemical formulation.
(260) As in EXAMPLE 49, the total surface energy was calculated using the classic “harmonic mean” method. The results are provided below:
(261) TABLE-US-00028 Release formulation Total Surface Energy (J/m.sup.2) Example 40 -- Aged 39.9 Example 40 49.1
(262) EXAMPLE 40, cured against an anti-static PET surface, exhibited a total surface energy of about 49 J/m.sup.2, which is significantly less hydrophobic than the “air-cured” sample. After this formulation was subjected to the standard aging procedure, the total surface energy decreased from about 49 J/m.sup.2 to about 40 J/m.sup.2. This result would appear to corroborate the RCA results obtained for the various aged and un-aged materials of this exemplary formulation.
Example 51
(263) The temperature on the blanket surface is maintained at 75° C. The image (typically a color gradient of 10-100%) is printed at a speed of 1.7 m/sec on the blanket, at a resolution of 1200 dpi. An uncoated paper (A4 Xerox Premium Copier Paper, 80 gsm) is set between the pressure roller and the blanket and the roller is pressed onto blanket, while the pressure is set to 3 bar. The roller moves on the paper, applying pressure on the contact line between blanket and paper and promoting the transfer process. In some cases, incomplete transfer may be observed, with an ink residue remaining on the blanket surface. In order to evaluate the extent of that ink residue, glossy paper (A4 Burgo glossy paper 130 gsm) is applied on the blanket similarly to the uncoated paper and the transfer process is again performed. Any ink that remained on blanket and was not transferred to the uncoated paper will be transferred to the glossy paper. Thus, the glossy paper may be evaluated for ink residue, according to the following scale (% of image surface area): A—no visible residue B—1-5% visible residue C—more than 5% visible residue Results of the evaluation are provided below:
(264) TABLE-US-00029 Release formulation Transfer grade Example 42 B Example 39 B Example 40 A Example 41 A Example 44 C
Example 52
(265) EXAMPLE 51 was repeated for the release surfaces of EXAMPLES 40 and 41, but at a printing speed of 3.4 m/sec on the blanket Both release surfaces retained a transfer grade of A.
Example 53
(266) The ITM release layer compositions of EXAMPLES 40 and 41 were cured against a PET substrate according to the procedure provided in EXAMPLE 39. The samples were then subjected to dynamic contact angle (DCA) measurements at 10 seconds and subsequently at 70 seconds, according to the following procedure:
(267) The drop is placed onto a smooth PTFE film surface with as little drop falling as possible, so that kinetic energy does not spread the drop. A pendant drop is then formed. Subsequently, the specimen is raised until it touches the bottom of the drop. If the drop is large enough, the adhesion to the surface will pull it off the tip of the needle. The needle tip is positioned above the surface at such a height that the growing pendant drop will touch the surface and detach before it falls free due to its own weight.
(268) The dynamic contact angle is then measured at 10 seconds and at 70 seconds. The results are provided below:
(269) TABLE-US-00030 Dynamic contact angle Cured against PET Example after 10 sec after 70 sec Ex 2 105° 97° Ex 3 87° 70°
(270) It is observed that the initial measurement of the dynamic contact angle, at 10 seconds, provides a strong indication of the hydrophilicity of the release layer surface. The subsequent measurement at 70 seconds provides an indication of the extent to which any liquid (such as a polyether glycol functionalized polydimethyl siloxane) disposed within the release layer has been incorporated into the drop. Such incorporation may further reduce the measured DCA.
Example 54
(271)
Example 55
(272)
(273) Concluding Remarks
(274) Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which the invention pertains. In case of conflict, the specification, including definitions, will take precedence.
(275) In the description and claims of the present disclosure, each of the verbs, “comprise” “include” and “have”, and conjugates thereof, are used to indicate that the object or objects of the verb are not necessarily a complete listing of members, components, elements, steps or parts of the subject or subjects of the verb. These terms encompass the terms “consisting of” and “consisting essentially of”.
(276) As used herein, the singular form “a”, “an” and “the” include plural references and mean “at least one” or “one or more” unless the context clearly dictates otherwise.
(277) Unless otherwise stated, the use of the expression “and/or” between the last two members of a list of options for selection indicates that a selection of one or more of the listed options is appropriate and may be made.
(278) As used herein in the specification and in the claims section that follows, the term “%” refers to percent by weight, unless specifically indicated otherwise.
(279) Similarly, the term “ratio”, as used herein in the specification and in the claims section that follows, refers to a weight ratio, unless specifically indicated otherwise.
(280) In the disclosure, unless otherwise stated, adjectives such as “substantially” and “about” that modify a condition or relationship characteristic of a feature or features of an embodiment of the present technology, are to be understood to mean that the condition or characteristic is defined to within tolerances that are acceptable for operation of the embodiment for an application for which it is intended.
(281) In the disclosure, unless otherwise stated, when a series of upper and lower limits are envisaged, every combination of upper and lower limits is explicitly envisaged. For example, in the following example where the transfer temperature T.sub.TRANSFER is at least 60° C., or at least 65° C., at least 70° C., or at least 75° C., at least 80° C., or at least 85° C., or at least 90° C., or at least 95° C., or at least 100° C., or at least 105° C., or at least 110° C., or at least 115° C. and the transfer temperature T.sub.TRANSFER is at most 65° C., or at most 70° C., or at most 75° C., or at most 80° C., or at most 85° C., or at most 90° C., or at most 95° C., or at most 100° C., or at most 105° C., or at most 110° C., or at most 115° C. Every individual temperature is explicitly envisaged: In some embodiments the transfer temperature T.sub.TRANSFER is at least 60° C. In some embodiments the transfer temperature T.sub.TRANSFER is at least 65° C. In some embodiments the transfer temperature T.sub.TRANSFER is at least 70° C. In some embodiments the transfer temperature T.sub.TRANSFER is at least 75° C. In some embodiments the transfer temperature T.sub.TRANSFER is at least 80° C. In some embodiments the transfer temperature T.sub.TRANSFER is at least 85° C. In some embodiments the transfer temperature T.sub.TRANSFER is at least 90° C. In some embodiments the transfer temperature T.sub.TRANSFER is at least 95° C. In some embodiments the transfer temperature T.sub.TRANSFER is at least 100° C. In some embodiments the transfer temperature T.sub.TRANSFER is at least 105° C. In some embodiments the transfer temperature T.sub.TRANSFER is at least 110° C. In some embodiments the transfer temperature T.sub.TRANSFER is at least 115° C.
(282) In addition, every combination of upper and lower limits is explicitly envisaged including: transfer temperature T.sub.TRANSFER of 60° C.-65° C., 60° C.-70° C., 60° C.-75° C., 60° C.-80° C., 60° C.-85° C., 60° C.-90° C., 60° C.-95° C., 60° C.-100° C., 60° C.-105° C., 60° C.-110° C. and 60° C.-115° C.; 65° C.-70° C., 65° C.-75° C., 605° C.-80° C., 65° C.-85° C., 65° C.-90° C., 65° C.-95° C., 65° C.-100° C., 65° C.-105° C., 65° C.-110° C. and 65° C.-115° C., etc.