ULTRA VIOLET CURABLE AQUEOUS INK COMPOSITION AND METHOD FOR PRODUCING SAME

Abstract

Disclosed are an aqueous UV curable ink and the method of preparing the same. In particular, the disclosure relates to a UV curable aqueous dispersant and a method of preparing the same; a UV curable aqueous ink composition and a method of preparing the same; and a method of forming an image on a recording medium. The UV curable aqueous dispersant according to the disclosure, and the UV curable aqueous ink composition including the same have no limitations in selecting a material, and improve the texture and fastness of an object, which is subjected to printing, in the fields of textile.

Claims

1-45. (canceled)

46. An ultraviolet (UV) curable aqueous dispersant comprising a UV curable functional group, wherein the UV curable functional group comprises a UV curable functional group for dispersing dyes/pigments, the UV curable aqueous dispersant comprises a styrene acrylic dispersant or styrene-maleic anhydride dispersant comprising the UV curable functional group, the UV curable functional group is introduced by chemical bonding.

47. The ultraviolet (UV) curable aqueous dispersant according to claim 46, the UV curable functional group comprises the following chemical formula (1), (2) or (3): ##STR00005## In the chemical formula (1), R.sub.1 is an allyl group or an acryl, methacrylic group including acryl, methacrylic, ethylene oxide or propylene oxide additives, ##STR00006## In the chemical formula (2), A.sub.1 and A.sub.2 is nitrogen or oxygen, when A.sub.1 and A.sub.2 are nitrogen, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 can be the same or different, and are hydrogen or an acryl, methacrylic group including allyl, acryl, methacrylic, ethylene oxide or propylene oxide additives, ##STR00007## In the chemical formula (3), A.sub.3 is oxygen or nitrogen, and R.sub.6 and R.sub.7 can be the same or different, and are an acryl, methacrylic group including allyl, acryl, methacrylic, ethylene oxide or propylene oxide additives.

48. An ultraviolet (UV) curable aqueous ink composition comprising: (a) the UV curable aqueous dispersant according to claim 46; (b) an aqueous amine comprising a UV curable functional group; and (c) one or more selected from among pigments and dyes.

49. The ultraviolet (UV) curable aqueous ink composition according to claim 48, the aqueous amine comprising the following chemical formula (4) or (5): ##STR00008## In the chemical formula (4), R.sub.8, R.sub.9 and R.sub.10 can be the same or different, and are hydrogen or an allyl, acryl, methacrylic group including allyl, acryl, hydroxyethyl, hydroxy(iso)propyl, hydroxy(iso)butyl, hydroxy(iso)pentyl, hydroxy(iso)hexyl, methacrylic, ethylene oxide or propylene oxide additives, ##STR00009## In the chemical formula (5), R.sub.11, R.sub.12, R.sub.13, R.sub.14 can be the same or different, and are alkyl or an allyl, acryl, methacrylic group including aryl, allyl, acryl, hydroxyethyl, hydroxy(iso)propyl, hydroxy(iso)butyl, hydroxy(iso)pentyl, hydroxy(iso)hexyl, methacrylic, ethylene oxide or propylene oxide additives, X is a halogen anion or a sulfonic acid anion.

50. The UV curable aqueous ink composition according to claim 48, further comprising one or more selected from among water-soluble and water-dispersible resins.

51. The UV curable aqueous ink composition according to claim 48, further comprising a UV curable monomer or oligomer.

52. The UV curable aqueous ink composition according to claim 48, further comprising an aqueous dispersant comprising no UV curable functional group.

53. The UV curable aqueous ink composition according to claim 48, wherein the ink composition comprises an ink composition for ink jet.

54. A method of preparing an ultraviolet (UV) curable aqueous ink composition, the method comprising: (a) preparing a UV curable aqueous dispersant comprising a UV curable functional group according to claim 46; (b) mixing the UV curable aqueous dispersant and an aqueous amine comprising a UV curable functional group, wherein it comprises neutralizing the aqueous dispersant with a monomer comprising a counter ion; and (c) adding one or more selected from among pigments and dyes.

55. The method of preparing an ultraviolet (UV) curable aqueous ink composition according to claim 54, wherein the aqueous amine comprises the following chemical formula (4) or (5): ##STR00010## In the chemical formula (4), R.sub.8, R.sub.9 and R.sub.10 can be the same or different, and are hydrogen or an allyl, acryl, methacrylic group including allyl, acryl, hydroxyethyl, hydroxy(iso)propyl, hydroxy(iso)butyl, hydroxy(iso)pentyl, hydroxy(iso)hexyl, methacrylic, ethylene oxide or propylene oxide additives, ##STR00011## In the chemical formula (5), R.sub.11, R.sub.12, R.sub.13, R.sub.14 can be the same or different, and are alkyl or an allyl, acryl, methacrylic group including aryl, allyl, acryl, hydroxyethyl, hydroxy(iso)propyl, hydroxy(iso)butyl, hydroxy(iso)pentyl, hydroxy(iso)hexyl, methacrylic, ethylene oxide or propylene oxide additives, X is a halogen anion or a sulfonic acid anion.

56. The method of preparing an ultraviolet (UV) curable aqueous ink composition according to claim 54, further comprising adding a UV curable monomer or oligomer.

57. The method of preparing an ultraviolet (UV) curable aqueous ink composition according to claim 54, further comprising an aqueous dispersant comprising no UV curable functional group.

58. A method of preparing an ultraviolet (UV) curable aqueous ink composition, the method comprising: (a) mixing an aqueous dispersant comprising no UV curable functional group and an aqueous amine comprising the UV curable functional group, wherein it comprises neutralizing the aqueous dispersant with a monomer comprising a counter ion; and (b) adding one or more selected from among pigments and dyes.

59. The method of preparing an ultraviolet (UV) curable aqueous ink composition according to claim 58, wherein the aqueous amine comprises the following chemical formula (4) or (5): ##STR00012## In the chemical formula (4), R.sub.8, R.sub.9 and R.sub.10 can be the same or different, and are hydrogen or an allyl, acryl, methacrylic group including allyl, acryl, hydroxyethyl, hydroxy(iso)propyl, hydroxy(iso)butyl, hydroxy(iso)pentyl, hydroxy(iso)hexyl, methacrylic, ethylene oxide or propylene oxide additives, ##STR00013## In the chemical formula (5), R.sub.11, R.sub.12, R.sub.13, R.sub.14 can be the same or different, and are alkyl or an allyl, acryl, methacrylic group including aryl, allyl, acryl, hydroxyethyl, hydroxy(iso)propyl, hydroxy(iso)butyl, hydroxy(iso)pentyl, hydroxy(iso)hexyl, methacrylic, ethylene oxide or propylene oxide additives, X is a halogen anion or a sulfonic acid anion.

60. The method of preparing an ultraviolet (UV) curable aqueous ink composition according to claim 58, further comprising adding a UV curable monomer or oligomer.

61. A method of forming an image on a recording medium, the method comprising: (a) printing the UV curable aqueous ink composition according to claim 48 onto a printing area surface of the recording medium; and (b) irradiating ink on the printing area surface with UV rays.

Description

DESCRIPTION OF DRAWINGS

[0080] FIG. 1 is a diagram structurally and chemically showing a method of preparing an ultraviolet (UV) curable aqueous ink composition according to the disclosure.

MODE FOR CARRYING OUT DISCLOSURE

[0081] Unless otherwise defined, all the technical and scientific terms used herein have the same meanings as those typically understood by those skilled in the art to which the disclosure pertains. In general, the nomenclature used herein is well known in the art and is typical.

[0082] According to an aspect, the disclosure relates to an ultraviolet (UV) curable aqueous dispersant (dispersion, aqueous dispersion solution, dispersion liquid) composition including (a) a base resin; and (b) a UV curable functional group.

[0083] Further, according to another aspect, the disclosure relates to a method of preparing a UV curable aqueous dispersant composition, the method including a step of introducing a UV curable functional group to a base resin.

[0084] In the disclosure, the term “aqueous” is a concept encompassing both water solubility and water dispersibility.

[0085] In the disclosure, the base resin refers to a binder-type dispersant that gives water dispersibility to pigments or dyes, and specifically may be an aqueous dispersant. As the aqueous dispersant according to the disclosure, the base resin may specifically include a styreneacrylic (SA) dispersant, a styrene-maleic anhydride (SMA)dispersant, an urethane(PU) dispersant, a linear polymer dispersant, or the like linear polymer dispersant; a star-burst or comb-type polymer dispersant modified from the linear polymer dispersant; or combination of one or more dispersants.

[0086] According to the disclosure, the base resin generally has an average molecular weight of 2,000 to 200,000, measured by gel permeation chromatography, and further generally has a molecular weight of 5,000 to 40,000.

[0087] In the disclosure, the base resin may be used as an auxiliary dispersant to increase an efficiency of preparing the dispersion liquid. The chemical composition of the base resin may include (meth)acrylate, (meth)acrylic acid copolymer, styrene-acrylic acid copolymer, etc., and may control adsorption with pigments and dispersibility in an aqueous or oily medium by adjusting a hydrophilicity-hydrophobicity ratio based on a percentage of monomers (i.e., hydrophobic monomers such as unsaturated acrylate, and hydrophilic monomers such as acrylic acid or hydroxy acryl) used during polymerization. Further, the base resin may increase the fixedness and gloss of the ink composition.

[0088] Further, the base resin, which is used as the auxiliary dispersant when the dispersion liquid according to the disclosure is prepared, may include commercially available dispersants, for example, Zetasperse 2500, Zetasperse 3100, Zetasperse 3400, Zetasperse 3600, or Zetasperse 3700 of the Air Product company; HPD 296, LMV 7025, Joncryl 693 or Joncryl 67 of the BASF company; DISPERBYK 194, DISPERBYK 190, DISPERBYK 199, DISPERBYK 2012, DIPERBYK 2010, DISPER 2014, BYKJET 9170, or BYKJET 9171 of the BYK company; SMA1000, SMA2000, SMA2021, or SMA3000 of the Total Petrochemical company; Solsperse WV400 of the Lubrizol company; JEFFSPERSE X3204 or JEFFSPERSE X3503 of the Huntsman company; etc., but is not limited thereto.

[0089] According to the disclosure, the UV curable functional group refers to functional group connected to each other based on a chemical crosslinking reaction that occurs between the UV curable functional groups as irradiated with UV rays. The UV curable functional group may be introduced into the base resin by chemical bonding.

[0090] In the disclosure, the UV curable functional group introduced into the base resin by chemical bonding specifically includes the following chemical formula.

##STR00001##

[0091] According to the disclosure, the UV curable functional group may have the above structure, in which R.sub.1 may be an allyl group or an acryl, methacrylic group including acryl, methacrylic, ethylene oxide or propylene oxide additives.

[0092] Further, according to the disclosure, the UV curable functional group may include the following structure in which the maleic anhydride ring is opened.

##STR00002##

[0093] Here, A.sub.1 and A.sub.2 may be nitrogen or oxygen. When A.sub.1 and A.sub.2 are nitrogen, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 may be the same or different, and may be hydrogen or an acryl, methacrylic group including allyl, acryl, methacrylic, ethylene oxide or propylene oxide additives.

[0094] Further, according to the disclosure, the UV curable functional group may have the following chemical structure,

##STR00003##

[0095] Here, A.sub.3 may be oxygen or nitrogen, and R.sub.6 and R.sub.7 may be the same or different, and may be an acryl, methacrylic group including allyl, acryl, methacrylic, ethylene oxide or propylene oxide additives.

[0096] In the disclosure, the UV curable dispersant may have an acid value higher than equal to 100 mgKOH/g or lower than or equal to 300 mgKOH/g. When the acid value of the dispersant is lower than 100 mgKOH/g, the dispersant has low solubility in water and is not suitable for dispersing aqueous pigments. On the other than, when the acid value of the dispersant is higher than 300 mgKOH/g, the dispersant has high solubility in water and hardly functions as the dispersant because the dispersant is not adsorbed to the surfaces of pigments and dispersion dyes but dissolved in water.

[0097] According to the disclosure, the UV curable aqueous dispersant composition may be characterized in maintaining the size of dispersed colloidal particles stably, and adjusting the speed of being adsorbed or absorbed in an object-to-be-subjected-to-printing according to points in time of irradiation of UV rays when ink is printed on the object so that a lot of pigment particles such as dispersion dyes and pigments can remain on the surface of the object or be strongly fixed after penetrating deep into the object.

[0098] According to another aspect, the disclosure is to provide a UV curable aqueous ink composition including (a) a UV curable aqueous dispersant composition; (b) an aqueous amine including a UV curable functional group; and (c) pigments or dyes.

[0099] The UV curable aqueous dispersant composition, and the UV curable functional group are the same as described above.

[0100] In the disclosure, the UV curable aqueous ink composition may additionally include a UV curable monomer or oligomer. In this case, the monomer or oligomer may be cationic, anionic, aqueous, or wettable, and the composition of the monomer or oligomer may be adjusted according to the characteristics of a material. When the UV curable monomer or oligomer is included, UV crosslinking performance may be improved because a crosslinking reaction occurs simultaneously with occurrence of a polymerization reaction due to irradiation of UV rays and heating according to the compositions.

[0101] According to the disclosure, the aqueous amine may include the UV curable functional group, in which the UV curable functional group may be chemically introduced. In the disclosure, the aqueous amine is an amine-based monomer that may be used as a counter ion of a dispersion resin and may also be used in a neutralization reaction of the commercially available dispersion resin. Further, when the dispersion resin is neutralized, the aqueous amine may be used mixing with anon-curable counter ion. In this case, a use ratio of UV curable counter ion and the UV non-curable counter ion may be appropriately adjusted to optimize dispersion properties.

[0102] The aqueous UV curable amine may include a primary amine, a secondary amine, a tertiary amine, or a quaternary amine, and may have the following structures.

##STR00004##

[0103] In the disclosure, R.sub.8, R.sub.9 and R.sub.10 may be the same or different, and may be hydrogen or an allyl, acryl, methacrylic group including allyl, acryl, hydroxyethyl, hydroxy(iso)propyl, hydroxy(iso)butyl, hydroxy(iso)pentyl, hydroxy(iso)hexyl, methacrylic, ethylene oxide or propylene oxide additives.

[0104] In the disclosure, R.sub.11, R.sub.12, R.sub.13, R.sub.14 may be the same or different, and may be alkyl or an allyl, acryl, methacrylic group including aryl, allyl, acryl, hydroxyethyl, hydroxy(iso)propyl, hydroxy(iso)butyl, hydroxy(iso)pentyl, hydroxy(iso)hexyl, methacrylic, ethylene oxide or propylene oxide additives.

[0105] In the disclosure, X is an anion as a counter ion to ammonium. Representatively, X may be a halogen anion or a sulfonic acid anion.

[0106] Specifically, X may be allylamine or its salt, diallylamineor its salt, triallylamineor its salt, DMAEMA (2-(dimethylamino)ethyl (meth)acrylate, DMEAEMA) or its salt, DMAEAAA (N,N-dimethylaminoethylacrylamide) or its salt, DEAEAA (diethylaminoethylacrylamide) or its salt, N-vinylpyrrolidone, vinylpyridine, N-vinylacetamide, N,N-bis(2-hydroxyethyl)acrylamide, N,N-bis(2-hydroxyethyl) methacrylamide, N-allyldiethanolamine or its salt, N,N-diallylethanolamine or its salt, diallyldihydroxyethylammoniumchloride, tetraallylammoniumchloride, triallylhydroxyethylchloride, dimethyldiallylammoniumchloride, N,N-diallylethylene oxide/propylene oxide additives, triallylethylene oxide/propylene oxide additives, or the like basic cationic or aqueous monomer, but not limited thereto.

[0107] The aqueous UV curable amine may use a monomer having characteristics of a wetting agent to prevent dryness on the outside.

[0108] According to the disclosure, the pigments or dyes include all of inorganic pigments, organic pigments, inorganic dyes, or organic dyes, and include pigments or dyes usable for jetting ink. Such pigments or dyes are additionally subjected to an encapsulation reaction based on a reaction with a crosslinking agent such as epoxide, carbodiimide, etc., thereby further improving colloidal safety.

[0109] According to the disclosure, a water-soluble and/or water-dispersible resin may be added to improve adhesion and elongation to a recording medium. According to the disclosure, the UV curable aqueous ink composition may be useful for inkjet ink and may be a colorant for painting, coating, fiber or stationery.

[0110] According to the disclosure, the ink composition may include one or more additives selected from the group consisting of a moisturizer, a surfactant, an initiator, a curing accelerator, an adhesion promotor, a water-soluble and/or water dispersible resin, a filler, a defoamer, a preservative, an anticoagulant, a polymerization retardant, and an antioxidant.

[0111] According to the disclosure, the water-soluble and/or water dispersible resin may include one or more selected from the group consisting of anionic or nonionic resins.

[0112] According to the disclosure, the initiator may be water-soluble or water-dispersible, and may include a photo-initiator, a thermal polymerization initiator, or a cationic initiator.

[0113] According to the disclosure, the moisturizer may include one or more selected from the group consisting of ethyleneglycol, propyleneglycol, diethyleneglycol, triethyleneglycol, pentamethyleneglycol, trimethyleneglycol, 2-butene-1,4-diol, 2-ethyl-1,3-hexanediol, 1,2-hexanediol, 2-methyl-2,4-pentanediol, tripropyleneglycol, polyethyleneglycol having a number average molecular weight of not more than 2000, 1,3-propyleneglycol, isopropyleneglycol, isobutyleneglycol, glycerin, diglycerin, and polyglycerin.

[0114] According to the disclosure, the surfactant may include one or more selected from the group consisting of an anionic surfactant, a cationic surfactant, a nonionic surfactant, and a fluorine surfactant.

[0115] Another aspect of the disclosure is to provide a method of preparing a UV curable aqueous ink composition, the method including the steps of (a) preparing a UV curable aqueous dispersant by introducing a UV curable functional group into a base resin; (b) preparing an aqueous amine including the UV curable functional group by introducing the UV curable functional group into an aqueous amine; (c) mixing the UV curable aqueous dispersant and an aqueous amine including the UV curable functional group; and (d) adding pigments or dyes.

[0116] The UV curable aqueous dispersant, the aqueous amine, the pigments, and the dyes are the same as described above.

[0117] According to the disclosure, the method of preparing the UV curable aqueous ink composition may additionally include the step of adding an aqueous UV-crosslinking monomer or oligomer. When the UV curable monomer or oligomer is included, UV crosslinking performance may be improved because a crosslinking reaction occurs and polymerization occurs due to irradiation of UV rays and heating.

[0118] Another aspect of the disclosure is to provide a method of forming an image on a recording medium, the method including the steps of (a) printing (or applying) a UV curable aqueous ink composition (or forming an image) on a printing area surface of the recording medium; and (b) irradiating UV rays to the ink on the printing area surface.

[0119] According to the disclosure, the recording medium refers to an object to which an ink composition is printed, or an object-to-be-subjected-to-printing, and may for example include fibers such as wool, silk, cotton, glass fiber, nylon, polyester; films such as polyethylene terephthalate (PET), polyvinylchloride (PVC), polycarbonate (PC), polyethylene (PE), polypropylene (PP), polyimide (PI); plastic; glass; wood; stone; metal; paper; etc., but is not limited thereto. In more detail, the recording medium may be a fabric, which may for example include natural fibers such as silk, cotton, and wool, and synthetic fibers such as nylon, polyester, and rayon, but is not limited to a specific material.

[0120] When ink on the printing area surface is irradiated with the UV rays, the aqueous dispersant is insolubilized due to a crosslinking reaction between the UV curable functional group of the dispersant and the UV curable functional group of the aqueous amine counter ion. In this case, an ionic bond and a chemical bond between the ink and an object-to-be-subjected-to-printing on the surface of the object reduce fluidity, improve image sharpness without spreading color, improve the fixedness of the ink to the object, thereby leading to the improvement in the fastness. In particular, in a cellulose microstructure of highly absorbent fibers and microfibers, physical fixedness between pigments and the microstructure of the object-to-be-subjected-to-printing becomes stronger according to UV curing conditions, thereby further improving the fastness against washing and friction.

[0121] According to the disclosure, in the image forming method, a pretreatment agent may use a cationic resin, an amine compound, a cationic monomer, a polymerization initiator, and a polyvalent metal salt or the like capable of preparing a water-insoluble complex such as Ca++, Mg++, etc. For example, the polymerization initiator may use ceric ammonium nitrate (CAN).

[0122] In the disclosure, the term “composition” is considered to encompass not only a product containing a specific ingredient but also any product made directly or indirectly by combining the specific ingredients.

EMBODIMENTS

[0123] Below, the disclosure will be described in more detail through embodiments. These embodiments are for illustrative purposes only, and it will be apparent for a person having ordinary knowledge in the art that the scope of the disclosure is not limited to these embodiments. Accordingly, the substantial scope of the disclosure will be defined by the appended claims and their equivalents.

Embodiment 1: Preparation of UV Curable Aqueous Dispersant

[0124] 1-1: Preparation of UV Curable Aqueous Dispersion Resin

[0125] A styrene-maleic anhydride resin was used as the base resin, and the UV curable functional group was prepared by introducing the compositions of the following Table 1 into theresin by chemical bonding.

Embodiment 1-1a

[0126] 100 g of SMA 2021F (Total Petrochemical) and 150 g of N-methylpyrrolidone (NMP) were mixed in a 4-neck round-bottom flask and completely dissolved at 40° C., and the mixture of 20 g of aniline and toluene 25 was added dropwise to the foregoing reaction solution. The reaction solution was reacted for 2 hours after raising its temperature to 60° C. The reaction solution was treated by the Dean-stark reflux reaction for 12 hours after raising its temperature to 150° C. After removing toluene from the reaction solution by distillation, the reaction solution was cooled down to 60° C., and then additionally reacted for 2 hours after adding 10 g of diallylamine and 10 g of Zepamine M2070 to the reaction solution. The reaction solution was re-precipitated in 4 L of purified water, and then filtering and cleaning were performed. Redispersion/filtration processes were performed three times to sufficiently remove the residual solvent, and drying was performed at 80° C. Finally, 121 g of a dried solid was obtained.

TABLE-US-00001 TABLE 1 1a 1b 1c 1d 1e 1f 1g 1h SMA 100 g  100 g  100 g  100 g 100 g 100 g 100 g  100 g Aniline 20 g 15 g 10 g 10 g 0 g 0 g  0 g 0 g Allylamine  0 g  0 g  0 g 5 g 15 g 20 g 10 g 5 g Diallylamine 10 g 15 g 20 g 0 g 0 g 0 g 10 g 20 g Zepamine M2070 10 g 10 g 10 g 10 g 15 g 15 g 15 g 15 g

Embodiments 1-1b to 1-1h

[0127] Compounds were obtained by performing the preparing processes in the same way as above except for using the raw materials in the ratios shown in the above Table 1.

Embodiment 2: Preparation of UV Curable Aqueous Dispersion Liquid

[0128] 2-1: Preparation of Dispersion Liquid

Embodiment 2-1a

[0129] 20 wt % of Disperse Red 60 and 10% of resin obtained in the embodiment 1-1a and neutralized with N,N′-dimethylethanolamine, 2% of styrene-acryl polymer dispersant (LMV7025, Basf) were mixed with water. This mixture was dispersed by the bead mill (or the dyno-mill, KD-Lab.) for 12 hours. The prepared dispersion liquid was let down to 15 wt % of solid with respect to a colorant, and then filtered to obtain a dispersion liquid 2-1a having an average particle size of 91.5 nm.

Embodiments 2-1b to 2-1h

[0130] Dispersion liquids 2-1b to 2-1h for dispersion dyes were prepared by the same method as that of preparing the foregoing dispersion liquid, in which the same processes are used except for different dispersants as shown in the following Table 2.

TABLE-US-00002 TABLE 2 Ratio of Average Dispersion pigments/dispersants Dispersion Dispersion particle size liquid Dispersion dyes Dispersant 1 Dispersant 2 (based on solid) time liquid pH (nm) 2-1a Disperse Red 60 1-1a LMV7025 5/3 12 8.6 91.5 2-1b Disperse Red 60 1-1b LMV7025 5/3 12 8.7 88.3 2-1c Disperse Red 60 1-1c LMV7025 5/3 12 8.9 80.4 2-1d Disperse Red 60 1-1d LMV7025 5/3 12 8.7 95.0 2-1e Pigment Blue 15:3 1-1e Zetasperse 2500 5/3 6 8.5 130.5 2-1f Pigment Blue 15:3 1-1f Zetasperse 2500 5/3 6 8.6 131.4 2-1g Pigment Blue 15:3 1-1g Zetasperse 2500 5/3 6 8.7 133.2 2-1h Pigment Blue 15:3 1-1h Zetasperse 2500 5/3 6 8.7 132.9

Embodiment 2-2a

[0131] 20 wt % of Pigment Blue 15:3 and 6% of styrene-acryl polymer dispersant neutralized with N,N′-diallylamine/triethanolamine (1/4) were mixed with water. This mixture was dispersed by the bead mill (or the dyno-mill, KD-Lab.). The prepared dispersion liquid was filtered to obtain a dispersion liquid 2-2a having an average particle size of 124.5 nm.

Embodiment 2-2b

[0132] 20 wt % of Pigment Blue 15:3 and 6% of styrene-acryl polymer dispersant neutralized with N,N′-diallylamine/triethanolamine (1/1) were mixed with water. This mixture was dispersed by the bead mill (or the dyno-mill, KD-Lab.). The prepared dispersion liquid was filtered to obtain a dispersion liquid 2-2b having an average particle size of 132.6 nm.

[0133] Each of the prepared dispersion liquids was put in a container and placed in a constant-temperature water tank having a temperature of 25° C. to stabilize the temperature of the dispersion liquid and then measure an average particle size, viscosity, and pH.

[0134] The average particle size was measured by Nanotrac™ 250 of Microtrac, and the viscosity was measured by the LVDV-II B-type viscometer of BROOKFEILD.

TABLE-US-00003 TABLE 3 Dispersion Average particle Viscosity liquid pH size (nm) (cps) 2-1a 8.6 91.5 3.88 2-1b 8.7 88.3 3.84 2-1c 8.9 80.4 3.62 2-1d 8.7 95.0 5.00 2-1e 8.5 130.5 10.4 2-1f 8.6 131.4 10.6 2-1g 8.7 133.2 9.7 2-1h 8.7 132.9 9.5 2-2a 8.2 124.5 9.1 2-2b 7.9 132.6 9.8

[0135] In result, as shown in the Table 3, each dispersion liquid had a small average particle size of 100 nm to 130 nm and showed a low viscosity, and therefore it was confirmed that each dispersion liquid has excellent physical properties for the UV curable aqueous ink composition.

Embodiment 3: UV Curability of UV Curable Aqueous Dispersion Liquid

[0136] To test the UV curability, 100 g of sample ink was prepared by adding the UV ray initiator and the wetting agent based on the compositions shown in the following table to the dispersion liquids of 2-1a to 2-1d obtained according to the embodiment 2.

[0137] Here, the wetting agent, the UV ray initiator, the surface tension modifier, etc. were commercially available products commonly used in the industry.

[0138] For the test, a drop of sample inks according to the embodiments and comparative examples was dripped on a PET film by a disposable pipette, dried as left at room temperature for 1 hour, and photocured as irradiated with the UV rays. Then, purified water was added dropwise to the sample so as to determine whether the pigment leaches and whether the shape of the cured ink is maintained.

TABLE-US-00004 TABLE 4 Embodiment Embodiment Embodiment Embodiment Embodiment Embodiment Embodiment Embodiments 3-1a 3-1b 3-1c 3-1d 3-2a 3-2b 3-2c Dispersion 33.3 g 33.3 g liquid 2-1a Dispersion — 33.3 g — 33.3 g liquid 2-1a Dispersion — 33.3 g — 33.3 g liquid 2-1a Dispersion 33.3 g liquid 2-1a Wetting a gent 20 g 20 g 20 g 20 g 20 g 20 g 20 g UV ray 0.5 g 0.5 g 0.5 g 0.5 g — — — initiator Surface tension 0.1 g 0.1 g 0.1 g 0.1 g 0.1 g 0.1 g 0.1 g modifier Purified water balance balance balance balance balance balance balance Curability Insoluble Insoluble Insoluble Insoluble Dissolved Dissolved Dissolved *Insoluble: the film of cured and dried ink was maintained without leaching of the piment when the purified water was added dropwise thereto. *Dissolved: the film of the cured and dried ink was destroyed or the pigment was leached into a solution with the purified water when the purified water was added dropwise thereto.

[0139] In result, as shown in the Table 4, the ink compositions according to the comparative examples 3-2a to 3-2c had problems in that the film of the cured and dried ink was destroyed or the pigment was leached when the purified water was added dropwise, but the ink compositions according to the embodiments 3-1a to 3-1d showed that the film of the cured and dried ink was stably maintained and the pigment does not leach even through the purified water was added dropwise.

[0140] Although specific embodiments of the disclosure have been described above in detail, it will be apparent for a person having ordinary skill in the art that these descriptions are merely embodiments and do not limit the scope of the disclosure. Accordingly, the substantial scope of the disclosure will be defined by the appended claims and their equivalents.