METHODS AND SYSTEMS TO DYE TEXTILE MATERIALS WITH DYE BLEND COMPOSITIONS HAVING DIFFERENTIAL DYE EXHAUST RATES

Abstract

Processes and apparatus for dyeing a textile product are provided whereby an undyed textile product is introduced into a substantially anaerobic dyeing chamber having an oxygen content of less than 1000 ppm oxygen therein, and at least two dye mixtures having a differential dye exhaustion rate of at least 10% are applied onto the textile product within the substantially anaerobic dying chamber. Thereafter the dyed textile product may be exposed to an oxygen-containing atmosphere so as to oxidize the applied dyes. At least one of the dyes may have a dye exhaustion rate of at least about 25%, or even at least about 50%. The embodiments herein are especially adapted to dyeing of textile products whereby one dye in the at least two dye mixtures is a sulfur dye and another dye in the at least two dye mixtures is a leuco indigo dye.

Claims

1. A process for dyeing a textile product comprising the steps of: (a) introducing an undyed textile product into at least one substantially anaerobic dyeing chamber having an oxygen content of less than 1000 ppm oxygen therein; (b) applying onto the textile product within the at least one substantially anaerobic dying chamber at least two dye mixtures having a differential dye exhaustion rate of at least 10%; and thereafter (c) discharging the textile product dyed according to step (b) so as to expose the textile product to an oxygen-containing atmosphere.

2. The process according to claim 1, wherein at least one of the dyes in the dye mixture has a dye exhaustion rate of at least about 25%.

3. The process according to claim 2, wherein at least one of the dyes in the dye mixture has a dye exhaustion rate of at least about 50%.

4. The process according to claim 1, wherein one of the dyes in the at least two dye mixtures is a sulfur dye.

5. The process according to claim 4, wherein the sulfur dye is present in an amount between about 0.1 to 99 wt. %, based on total weight of the dyes in the at least two dye mixtures.

6. The process according to claim 5, wherein the sulfur dye is present in an amount between 1.0 to 75 wt. %, based on the total weight of the dyes in the at least two dye mixtures.

7. The process according to claim 5, wherein the sulfur dye is present in an amount between 10 to 60 wt. %, based on the total weight of the dyes in the at least two dye mixtures.

8. The process according to claim 4, wherein another dye in the at least two dye mixtures is a leuco indigo dye.

9. The process according to claim 1, wherein the at least two dye mixtures respectively comprise a sulfur dye and a leuco indigo dye.

10. The process according to claim 9, wherein step (b) comprises forming a blend of the at least two dye mixtures and then applying the blend of the at least two dye mixtures onto the textile product.

11. The process according to claim 1, wherein first and second ones of the at least two dye mixtures are applied successively onto the textile product in respective substantially anaerobic dyeing chambers.

12. The process according to claim 11, wherein the process comprises exposing the textile product to an oxygen environment intermediate of the respective anaerobic dyeing chambers.

13. The process according to claim 11, wherein the process comprise at least partially drying the textile product intermediate of the respective anaerobic dyeing chambers.

14. An apparatus for dyeing a textile product comprising: at least one substantially anaerobic dyeing chamber having an oxygen content of less than 1000 ppm therein for dyeing a textile product; and a dye application system to apply onto the textile product within the substantially anaerobic dying chamber at least two dye mixtures having a differential dye exhaustion rate of at least 10%.

15. The apparatus according to claim 14, which further comprises a mixture for blending the at least two dye mixtures with one another.

16. The apparatus according to claim 14, which further comprises first and second substantially anaerobic dyeing chambers each having an oxygen content of less than 1000 ppm for successively dyeing the textile product with first and second ones of the at least two dye mixtures, respectively.

17. The apparatus according to claim 16, which further comprises an oxygen environment intermediate the first and second substantially anaerobic dyeing chambers.

18. The apparatus according to claim 16 which further comprises a drier intermediate the first and second substantially anaerobic dyeing chambers.

19. The apparatus according to claim 14, further comprising a drier downstream of the at least one dyeing chamber.

20. The apparatus according to claim 14, which further comprises an inert gas system for supplying an inert gas to the at least one dyeing chamber.

21. A dyed textile product which is produced by the process according to claim 1.

Description

BRIEF DESCRIPTION OF ACCOMPANYING DRAWINGS

[0013] The disclosed embodiments of the present invention will be better and more completely understood by referring to the following detailed description of exemplary non-limiting illustrative embodiments in conjunction with the drawings of which:

[0014] FIGS. 1 and 2 are schematic flow charts of a system that may be employed in the practice of the embodiments disclosed herein to form a blended mixture of at least two different dyes having differential dye exhaust rates; and

[0015] FIGS. 3 and 4 are schematic flow charts showing alternative textile application techniques for the separate application of at least two different dyes having differential dye exhaustion rates onto a textile substrate.

DETAILED DESCRIPTION OF EMBODIMENTS

A. Definitions

[0016] As used herein and in the accompanying claims, the terms below are intended to have the following definition:

[0017] “Filament” means a fibrous strand of extreme or indefinite length.

[0018] “Fiber” means a fibrous strand of definite length, such as a staple fiber.

[0019] “Yarn” means a collection of numerous filaments or fibers which may or may not be textured, spun, twisted or laid together.

[0020] “Textile material” means any filament, fiber and/or yarn formed of a synthetic (man-made) or natural material.

[0021] “Fabric” means a textile material in the form of a cloth formed of a cloth formed of non-woven, woven or knitted filaments, fibers and/or yarns.

[0022] “Dye” means a natural or synthetic substance that adds color to or changes the color of a material to which it is applied.

[0023] “Dye exhaustion” or “dye exhaust” means the percentage (%) mass of dye that is taken up from a dye bath by a textile material relative to the original mass of dye in the dye bath.

[0024] “Dye exhaustion rate” or “dye exhaust rate” means the percentage (%) mass of dye that is taken up from a dye bath by a textile material relative to the original mass of dye in the dye bath per unit time (hr.).

[0025] “Differential dye exhaustion” means the absolute numerical percentage difference of two dyes having different dye exhaust rates.

[0026] “Dye mixture” means an aqueous mixture or blend of one dye in water with other optional components such as foaming agents, wetting agents, reducing agents and the like.

[0027] “Sulphur bottoming” means indigo dyeing being applied initially to a textile material before the application of indigo dyeing to produce textile products having a darker, brighter effect.

[0028] “Sulfur topping” means sulfur dye being applied to a textile material after the indigo dyeing.

[0029] “Foaming agent” is a chemical which causes foaming of the liquid dye composition, including for example, nonionic, anionic, cationic and awitterionic surfactants.

[0030] “Wetting agent” is a surfactant which lowers the advancing contact angle and aids in displacing air at the interface with the liquid phase. Suitable wetting agents include nonionic, anionic, cationic and zwitterionic surfactants such as glucosides, amine oxides, sulfosuccinates, sulfonates, phosphonates, ethoxylates and the like. Wetting agents with a Draves wetting time of <40 seconds are preferred. The same material may serve as both a foaming agent and a wetting agent.

B. Description of Embodiments

[0031] As is schematically depicted below in formula (I), an indigo dye molecule may be reduced to its leuco form by contact with, e.g., sodium dithionite, which in turn may then be reconverted to an indigo dye molecule via oxidation (e.g., exposure to an oxygen-containing environment, typically atmospheric air).

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[0032] The indigo dye molecule is deep blue in color whereas the leuco form of the molecule is yellowish in color. It is the leuco form of the indigo dye molecule (sometimes hereinafter more simply referenced as “leuco-indigo”) which is employed in the practice of the embodiments described herein. The leuco-indigo (sometimes referenced in the art as “pre-reduced indigo”) may be obtained from various commercial sources, for example, from DyStar Textilfarben GmbH & Co., manufactured according to U.S. Pat. No. 6,428,581 (the entire content of which is expressly incorporated hereinto by reference).

[0033] Sulfur dyes commonly used as add-on for black, blue, brown, khaki and green colors. Sulfur dyes can be applied with little difficulty and with excellent results at a relatively low cost. Sulfur dyeing procedures have been used to create a range of colors in conjunction with indigo.

[0034] Sulfur augmentation is also typically used in denim business. For example, sulfur bottoming may be employed to produce a darker color of a cotton yarn or textile fabric with less indigo. Sulfur topping on the other hand permits much darker color than sulfur bottoming can achieve, but is typically duller in appearance. Sulfur topping colors include black, blue-black, yellow brown and green. Sulfur toppings are used to produce slub appearances in normal yarn.

[0035] The embodiments of this invention address at least some of these challenges in the current art.

[0036] In general, the embodiments disclosed herein employ dye compositions comprised of a uniform blend or mixture of at least two dyes with different dye exhaustions that are applied to a textile material (e.g., textile materials formed of natural fibers, e.g., cotton) in a low-wet pick technique. The differential dye exhaustions of the dyes in the blend or mixture of dyes is most preferably at least 10%, preferably at least about 20% and more preferably at least about 50%. At least one of the dyes of the at least two dyes will preferably have a dye exhaust rate at the dyeing conditions of the textile product of at least about 25%, preferably at least about 50%.

[0037] The blend is applied onto the textile material substrate in a controlled manner using low wet application techniques such as direct metering of (a) the neat liquid due blend, (b) foam that is produced by incorporating gas into the dye liquid in the presence of a foaming agent, or (c) dye liquid spray of uniform droplet sizes. It could also include other methods such as passing the substrate through a kiss roll or a puddle. During application, the environmental conditions around the applicator, such as temperature, humidity and oxygen levels, need to be maintained to maintain stability of the liquid.

[0038] Once the dye liquid blend has been applied, the dyes will diffuse into the textile material substrate for a period of a few seconds, e.g., about 5 to about 120 seconds. During this period of time, the textile material substrate needs to be in an environment that ensures stability while promoting diffusion/penetration into the substrate.

[0039] After the diffusion step, the substrate is treated chemically or by heat to cause the materials to become insoluble.

[0040] Specific embodiments of the invention are shown schematically by FIGS. 1-4. As can be seen from FIG. 1, a system 10 is provided with a number of sources (e.g., vats or containers) of chemical constituents that may be included in the dye liquid formulation, including a source 12 for deoxygenated water, a source 14 for a foaming agent, a source 16 for a wetting agent and a source 18 for miscellaneous auxiliary materials. The various constituents from sources 12-18 may be metered as needed to Mixer 1 and Mixer 2 identified by blocks 20, 22, respectively whereby can be homogenously mixed together.

[0041] Dyes having different dye exhaustions identified as Dye 1 and Dye 2 may be withdrawn from sources 24, 26 and introduced with the mixed chemicals downstream of the Mixer 1 and Mixer 2, respectively (e.g., by being introduced to the downstream constituent mixture via a static in-line mixer 20a, 20b, respectively) thereby forming a liquid Dye 1 Mix and Dye 2 Mix as identified by blocks 28, 30, respectively. Preferably, these liquid dye mixtures of Dye 1 Mix and Dye 2 Mix are blended together to form a blend or mixture of dyes identified by block 32.

[0042] As shown in FIG. 1, all sources and unit operations in the system 10 are maintained in an essentially deoxygenated (anaerobic) state (i.e., an oxygen content of less than about 1000 ppm oxygen, preferably less than about 500 ppm oxygen, or less than about 200 ppm oxygen, or less than about 100 ppm oxygen, or less than about 75 ppm oxygen or even less than about 50 ppm oxygen, including essentially 0 ppm oxygen) by providing an inert gas to the same from an inert gas source 34 that has been purified via gas purifier 36.

[0043] As shown in FIG. 2, the blended liquid mixture of Dyes 1 and 2 from block 32 may be directed toward a foam generator or spray generator 34 form a foam or spray, respectively of the dye mixture that can then be supplied to an applicator 42 within the dyeing apparatus 40. The apparatus 40 may be, for example the apparatus as more fully disclosed in U.S. Pat. No. 10,619,292 whereby the liquid dye mixture is applied to a textile material (e.g., a sheet of parallel yarns) via the applicator 42 and transferred subsequently to a dwell chamber 44 to allow dye penetration into the textile material all under an inert atmosphere (preferably substantially anaerobic) due to the inert gas supplied from the gas purifier 36. Thereafter, the dyed yarns in the yarn sheet may be exposed to oxygenated conditions (e.g., ambient oxygen) as identified by block 46 to thereby oxidize the indigo dye molecule and achieve the indigo color. The dyed yarn sheet may then be passed to further downstream processing stations, e.g., drying and/or winding operations.

[0044] FIG. 3 shows a similar system to that described above for FIG. 2 with the principal exception being that individual supplies of Dye 1 and Dye 2 noted by blocks 28 and 30, respectively may be directed to respectively separate foam or spray generators identified by blocks 50, 52. These separate foam or spray generators 50, 52 may then in turn separately supply dedicated applicators identified by blocks 54, 56, respectively, within the dying apparatus 10′ each of which is provided with a separate downstream dwell chamber identified by blocks 58, 60, respectively.

[0045] As yet a further embodiment, the system shown in FIG. 3 may be modified as shown in FIG. 4 so as to include a sequential series of dye apparatus 10′, 10″, each of which is provided with separate applicators 54′, 56′, dwell chambers 58′, 60′ and oxidation zones 62′, 64′.

[0046] The embodiments disclosed herein will be further understood by reference to the following examples.

EXAMPLES

[0047] The Dye Mix 1 may contain the following constituents: [0048] Total Water content=up to 50 wt. %, preferably up to 30 wt. %, based on total weight of the liquid dye mixture [0049] Dye 1: Soluble form of indigo/vat dyes (i.e., reduced Leuco or Prereduced Leuco dyes) in an amount of about 10 wt. % to about 90 wt. % [0050] Foaming+Wetting agents in an amount of 0.1 wt. % to about 10 wt. % [0051] Miscellaneous constituents: e.g., viscosity modifiers, pH adjustors and/or reducing Agents

[0052] The following Table 1 shows exemplary formulations for the Dye Mix 1:

TABLE-US-00001 TABLE 1 Ex 1-1 Ex 1-2 Ex 1-3 Ex 1-4 Ex 1-5 Ex 1-6 Ex 1-7 Foaming Unifroth 1672 Unifroth 1672 Unifroth 1672 Unifroth 1672 Unifroth 1672 Ecosurf SA 7 Ammonyx Agent (100%) @ 3 (100%) @ 3 (100%) @ 2 (100%) @ 3 (100%) @ 3 (100%) @ 2 LMDO (40%) wt % wt % wt % wt % wt % wt % @ 5 wt % Wetting Uniwet 2413 Glucopon Glucopon Atesan LPW Atesan LPW Glucopon Glucopon Agent (25%) @ 8 215 (60%) 420 UP @ 2 wt % @ 2 wt % 420 UP 420 UP wt % @ 1 wt % (60%) @ 2 (60%) @ 2 (60%) @ 2 wt % wt % wł% Dye 1 Prereduced Prereduced Prereduced Prereduced Prereduced Prereduced Prereduced Indigo (40 Indigo (40%) Indigo (40%) Indigo (40%) Vat Blue 36 Indigo (40%) Indigo (40%) vol %) @ 20 @ 10 wt % @ 10 wt % @ 0.5 wt % @ 8 wt % @ 10 wt % + @ 10 wt % wt % Prereduced Vat Green 1 @ 0.4% Water balance balance balance balance balance balance balance

[0053] The Dye Mix 2 may contain the following constituents: [0054] Total Water content=up to 50 wt. %, preferably up to 30 wt. %, based on total weight of the liquid dye mixture [0055] Dye 2: Reduced form of at least one sulfur dye in an amount of about 10 wt. % to about 90 wt. % [0056] Foaming+Wetting agents in an amount of 0.1 wt. % to about 10 wt. % [0057] Miscellaneous constituents: e.g., viscosity modifiers, pH adjustors and/or reducing Agents

[0058] The sulfur dyes forming Dye 2 may be one or more of the following: [0059] Leuco Sulfur Black 1: Diresul brand (RDT Black or Indiblack RDT or Fast black) or Patcosul Black or equivalent. [0060] Leuco Sulfur Navy: Diresul brand Indinavy RDT or Navy RDT or equivalent [0061] Leuco Sulfur Blue: Diresul (Blue or Indiblue RDT or Arctic Blue or Pacific Blue or Caribbean blue) [0062] Leuco Sulfur RDT Colors: Diresul (Yellow RDT, Orange RDT, Brown RDT, Red RDT, Green RDT, Olive RDT) [0063] The following Table 2 shows exemplary formulations for the Dye Mix 2:

TABLE-US-00002 TABLE 2 Ex 2-1 Ex 2-2 Ex 2-3 Ex 2-4 Ex 2-5 Ex 2-6 Ex 2-7 Foaming Unifroth 1672 Unifroth 1672 Unifroth 1672 Unifroth 1672 Unifroth 1672 Ecosurf SA 7 Ammonyx Agent (100%) @ 3 (100%) @ 3 (100%) @ 2 (100%) @ 3 (100%) @ 3 (100%) @ 2 LMDO (40%) wt % wt % wt % wt % wt % wt % @ 5 wt % Wetting Uniwet 2413 Glucopon Glucopon Atesan LPW Atesan LPW Glucopon Glucopon Agent (25%) @ 8 215 (60%) 420 UP @ 2 wt % @ 2 wt % 420 UP 420 UP wt % @ 1 wt % (60%) @ 2 (60%) @ 2 (60%) @ 2 wt % wt % wt % Dye 2 Sulfur Black Sulfur Black Sulfur Black Leuco Sulfur Diresul Red Diresul Greet Diresul 1 (Sulfur 1 (Sulfur 1 (Sulfur Black @ @ 3.0 wt. % RDT @ 4.0 Indiblack @ RDT 4G) @ RDT 4G) @ RDT 4G) @ 0.7 wt % and wt. % 20 wt. % 0.7 wt. % 1.0 wt. % 20 wt. % Sulfur Navy @ 0.4 wt. % Viscosity Thickner Thickner Modifier 2515 @ 0.5 2515 @ 4 wt. % wt. % Water balance balance balance balance balance balance balance

[0064] The blended mix of Dye 1 and Dye 2 will thus preferably include: [0065] Total Water content=up to 50 wt. %, preferably up to 30 wt. %, based on total weight of the liquid dye mixture [0066] Dye 1 and Dye 2 in an amount of about 10 wt. % to about 90 wt. % based on total weight of the blended mix of Dye 1 and Dye 2, with [0067] Dye 2 being present in an amount of 0.1 to 99 wt. %, preferably between about 1.0 to about 75 wt. %, e.g., about 10 to about 60 wt. %, based on the total amount of Dye 1 and Dye 2 in the blended mix. [0068] Foaming+Wetting agents in an amount of 0.1 wt. % to about 10 wt. % [0069] Miscellaneous constituents: e.g., viscosity modifiers, pH adjustors and/or reducing Agents

[0070] The following Table 3 shows exemplary formulations for the blended mix of Dyes 1 and 2:

TABLE-US-00003 TABLE 3 Ex 3-1 Ex 3-2 Ex 3-3 Ex 3-4 Ex 3-5 Ex 3-6 Ex 3-7 Foaming Unifroth Unifroth Unifroth Unifroth Unifroth Unifroth Unifroth Agent 1672 1672 1672 1672 1672 1672 1672 (100%) @ 3 (100%) @ 3 (100%) @ 3 (100%) @ 2 (100%) @ 3 (100%) @ 3 (100%) @ 3 wt % wt % wt % wt % wt % wt % wt % Wetting Uniwet Glucopon Glucopon Glucopon Glucopon Glucopon Uniwet Agent 2413 (25%) 215 (60%) 215 (60%) 420 (60%) 215(60%) 215(60%) 2413 (25%) @ 8 wt % @ 1 wt % @ 2 wt % @ 2 wt % @ 2 wt % @ 2 wt % @ 8 wt % Dye 1 Prereduced Prereduced Prereduced Prereduced Prereduced Prereduced Prereduced Indigo Indigo Indigo Indigo Indigo Indigo Indigo (40%) @ (40%) @ (40%) @ (40%) @ (40%) @ 0 (40%) @ 0 (40%) @ 20 wt % 20 wt % 7.5 wt % 10 wt % wt % wt % 20 wt % Dye 2 Leuco Leuco Leuco Leuco Diresul Red Diresul Sulfur RDT Sulfur Black Sulfur Black Sulfur Black Sulfur Black @ 3% Green RDT 4G @ 0.7 1 (Sulfur 1 (Sulfur 1 (Sulfur @ 0.7% and @ 4% wt % RDT 4G) @ RDT 4G) @ RDT 4G) @ Sulfur Navy 0.7 wt % 1 wt % 20 wt % @ 0.4% Viscosity Thickener Thickener Thickener Modifier 2515 @ 2515 @ 2% 2515 @ 5% 0.5% Water balance balance balance balance balance balance balance

[0071] While reference is made to a particular embodiment of the invention, various modifications within the skill of those in the art may be envisioned. Therefore, it is to be understood that the invention is not to be limited to the disclosed embodiment, but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope thereof.