Intaglio printing UV curing water-based ink and preparation method thereof

Abstract

The invention discloses an intaglio printing UV curing water-based ink and a preparation method thereof, and belongs to the technical field of ink preparation, the water-based ink comprises the following components: 100 parts of a polyacrylic acid emulsion and / or a polyacrylate emulsion, 5-18 parts of a hydroxyl acrylate monomer, 6-16 parts of a modified monomer, 9-20 parts of aliphatic polyurethane acrylate, and 5-15 parts of a lower alcohol solvent, 10-30 parts of pigment filler, 1-8 parts of an initiator and 1-10 parts of an auxiliary agent; by introducing the modified monomer, the polymerization curing rate of the resin binder is improved, and meanwhile, the adhesion performance of the resin binder is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of ink preparation, and particularly relates to a gravure printing UV-curable water-based ink and a preparation method thereof. Background Art

[0002] Gravure printing is widely used in the food, pharmaceutical, and tobacco packaging industries, which is closely related to people's life and health. A large amount of volatile organic solvents are used in traditional gravure printing inks, which not only pollute the environment, but also the residual organic solvents in printed products are harmful to human health. With the increasing rapid development of human civilization, sustainable development and environmental protection have become social trends. The development and application of water-based inks can greatly improve the printing operation environment and enhance product quality and safety, thus attracting the attention and favor of the packaging and printing industry. The curing principle of water-based gravure inks is based on the photopolymerization reaction initiated by ultraviolet light. The main components of the ink include photoinitiators, reactive resins (such as acrylates), monomers, pigments, and additives. During the printing process, after the ink cavities of the gravure cylinder are filled with ink, the excess ink on the surface is scraped off by a doctor blade, and only the ink in the cavities is retained. Subsequently, under the action of pressure, it is transferred to the surface of the substrate. At this time, the ink has not yet cured and remains liquid. When the printed product passes through an ultraviolet light irradiation device (UV lamp), the photoinitiator absorbs the ultraviolet light energy of a specific wavelength (usually 200 - 400 nm), decomposes to generate active free radicals or cations, triggers the chain polymerization reaction between the resin and the monomer, and forms a three-dimensional network structure, thereby completing the curing.

[0003] Acrylate emulsion is a commonly used film-forming agent for gravure printing UV inks and is widely used in water-based gravure inks. However, its internal curing speed is much slower than that of the surface, and it generally faces problems such as slow drying and poor adhesion. Summary of the Invention

[0004] In view of the above problems, the present invention provides a gravure printing UV-curable water-based ink and a preparation method thereof.

[0005] The purpose of the present invention is achieved by the following technical solutions:

[0006] A gravure printing UV-curable water-based ink, by weight, comprises the following components: 100 parts of polyacrylic acid emulsion and / or polyacrylate emulsion, 5 - 18 parts of hydroxyacrylate monomer, 6 - 16 parts of modified monomer, 9 - 20 parts of aliphatic polyurethane acrylate, 5 - 15 parts of lower alcohol solvent, 10 - 30 parts of pigment and filler, 1 - 8 parts of initiator, and 1 - 10 parts of additive;

[0007] The preparation method of the modified monomer comprises the following steps:

[0008] (1) Mix benzaldehyde and tert-butyl acrylate, add a catalyst, and stir the reaction at room temperature for 24 - 48 h. After the reaction is completed, wash successively with hydrochloric acid solution and saturated brine, dry, and then remove the solvent under reduced pressure to obtain product A; dissolve the product A in dichloromethane, add acetic anhydride and N,N-dimethylaminopyridine, and stir the reaction at room temperature for 12 - 20 h. After the reaction is completed, wash successively with hydrochloric acid solution and saturated brine, dry, and then remove the solvent under reduced pressure to obtain product B;

[0009] (2) Dissolve the product B in tetrahydrofuran, add 1,4-diazabicyclo[2.2.2]octane, stir and mix, then add 2-mercaptopropionic acid and stir the reaction for 1 - 2 h. Evaporate the solvent, dissolve in ethyl acetate, wash successively with hydrochloric acid solution and saturated brine, dry, and then remove the solvent under reduced pressure to obtain product C; dissolve the product C in dioxane, add hydrochloric acid and heat under reflux at 80 - 100 °C for 1 - 4 h. After cooling, dilute with water, extract with ethyl acetate, wash with saturated brine, dry, and then remove the solvent under reduced pressure to obtain product D;

[0010] (3) Dissolve the product D in dichloromethane, add a solution of oxalyl chloride in dimethylformamide, and stir the reaction at room temperature for 1 - 4 h to obtain solution A; simultaneously drip the solution A and a solution of 1,4-butanediol into a solution of pyridine, stir the reaction for 1 - 2 h, remove the precipitate, wash with hydrochloric acid solution, concentrate, and then purify by column chromatography to obtain product E; dissolve the product E in dichloromethane, add m-chloroperoxybenzoic acid under cooling conditions, and stir the reaction at room temperature for 1 - 4 h. Remove the precipitate, and evaporate the solvent from the supernatant under reduced pressure to prepare.

[0011] In some preferred embodiments, in step (1), the mass ratio of the benzaldehyde, the tert-butyl acrylate, and the catalyst is 1:(1.2 - 1.5):(0.8 - 0.9); the mass ratio of the product A, the acetic anhydride, and the N,N-dimethylaminopyridine is 10:(5 - 5.8):(1 - 1.6).

[0012] In some preferred embodiments, in step (2), the mass ratio of the product B, the 1,4-diazabicyclo[2.2.2]octane, and the 2-mercaptopropionic acid is 1:(0.85 - 1):(0.35 - 0.45); the mass ratio of the product C and the hydrochloric acid is 10:(2 - 3).

[0013] In some preferred embodiments, in step (3), the mass ratio of the product D, the oxalyl chloride, the 1,4-butanediol, and the pyridine is 1:(1.7 - 2.1):(0.35 - 0.5):(1.3 - 1.8); the mass ratio of the product E and the m-chloroperoxybenzoic acid is 1:(1.5 - 2.2).

[0014] In some preferred embodiments, the polymerization molecular weight of the polyacrylic acid emulsion and the polyacrylate emulsion is 100,000 - 150,000, the pH value is 6 - 8, and the solid content is 35% - 45%.

[0015] In some preferred embodiments, the hydroxyacrylate monomer is one or more of 2 - hydroxy - 3 - phenoxypropyl acrylate, β - hydroxyethyl methacrylate, β - hydroxypropyl acrylate, and β - hydroxypropyl methacrylate.

[0016] In some preferred embodiments, the lower alcohol solvent is an alcohol solvent with 1 - 5 carbon atoms.

[0017] In some preferred embodiments, the pigment and filler include pigments and fillers. The pigments are one or more of phthalocyanine pigments, carbon black, and titanium white; the fillers are one or more of matte powder, talc powder, calcium carbonate, and silicon dioxide.

[0018] In some preferred embodiments, the initiator is one or more of 1 - hydroxy - cyclohexylbenzophenone, 2,4,6 - trimethylbenzoyl - diphenylphosphine oxide, 2 - hydroxy - 2 - methyl - phenylacetone - 1, 2,4,6 - trimethylbenzoyl - ethoxy - phenylphosphine oxide, and 2 - hydroxy - 2 - methyl - p - hydroxyethyl ether - phenylacetone - 1.

[0019] In some preferred embodiments, the additives are one or more of dispersants, emulsifiers, stabilizers, softeners, preservatives, defoamers, pH regulators, adhesion promoters, antistatic agents, thickeners, and light absorbers.

[0020] The second aspect of the present invention is to provide a method for preparing the gravure printing UV - curable water - based ink, comprising the following steps:

[0021] S1. Weigh each raw material according to the proportion and set aside.

[0022] S2. Mix the polyacrylic acid emulsion and / or polyacrylate emulsion, the hydroxyacrylate monomer, the modified monomer, the aliphatic polyurethane acrylate, the lower alcohol solvent, the initiator, and the additives, stir well until completely dissolved, then add the pigment and filler, continue to stir until evenly dispersed, and grind in a grinding machine to the desired fineness to obtain the gravure printing UV - curable water - based ink.

[0023] The beneficial effects of the present invention are:

[0024] In view of the problems existing in the prior art that the internal curing speed of acrylate emulsion as the film-forming agent of gravure printing UV-curable water-based ink is much slower than that of the surface, the drying is slow, and the adhesion is poor, the present invention provides a gravure printing UV-curable water-based ink. By introducing a modified monomer, the polymerization curing rate of the resin binder is increased, and at the same time, its adhesion performance is improved. Specifically, the modified monomer of the present invention uses benzaldehyde as a raw material, and successively generates an addition product through the MBH reaction with tert-butyl acrylate, esterification, reaction with 2-mercaptopropionic acid to generate a thioether compound, hydrolysis and then esterification with butanediol to form a ring, and finally oxidizes with m-chloroperoxybenzoic acid to obtain. Through modification, the present invention uses tert-butyl acrylate as the modification matrix to obtain a modified monomer with both acryloyl and ring structures, and by introducing a sulfur ether oxide structure, it promotes the electron transfer and radical ring-opening polymerization in the photocuring reaction, improves the polymerization reaction activity of the monomer, and further improves the drying speed and adhesion of the ink. Detailed implementation mode

[0025] The present invention will be further described in conjunction with the following embodiments.

[0026] Example 1

[0027] A gravure printing UV-curable water-based ink, by weight, comprises the following components: 30 parts of polyacrylic acid emulsion, 70 parts of polyacrylate emulsion, 12 parts of hydroxyacrylate monomer, 10 parts of modified monomer, 15 parts of aliphatic polyurethane acrylate (CAS No.: 68987-79-1), 7 parts of lower alcohol solvent, 6 parts of pigment, 13 parts of filler, 2 parts of initiator, 1 part of dispersant, 0.6 part of defoamer, 2.2 parts of pH regulator;

[0028] The preparation method of the modified monomer comprises the following steps:

[0029] (1) Mix benzaldehyde and tert-butyl acrylate, add 1,8-diazabicyclo[5.4.0]undec-7-ene, stir and react at room temperature for 30 h. After the reaction is completed, wash successively with hydrochloric acid solution and saturated brine, dry and then distill off the solvent under reduced pressure to obtain product A; dissolve the product A in dichloromethane, add acetic anhydride and N,N-dimethylaminopyridine, stir and react at room temperature for 16 h. After the reaction is completed, wash successively with hydrochloric acid solution and saturated brine, dry and then distill off the solvent under reduced pressure to obtain product B; the mass ratio of the benzaldehyde, the tert-butyl acrylate and the 1,8-diazabicyclo[5.4.0]undec-7-ene is 5.3:6.4:4.5; the mass ratio of the product A, the acetic anhydride and the N,N-dimethylaminopyridine is 6:3.2:0.64;

[0030] (2) Dissolve the product B in tetrahydrofuran, add 1,4-diazabicyclo[2.2.2]octane, stir and mix, then add 2-mercaptopropionic acid and stir for reaction for 1 h. Evaporate the solvent, dissolve it with ethyl acetate, wash it successively with 5% hydrochloric acid solution and saturated brine, dry it, and then evaporate the solvent under reduced pressure to obtain product C; dissolve the product C in dioxane, add hydrochloric acid and heat it under reflux at 90 °C for reaction for 2 h, cool it, dilute it with water, extract it with ethyl acetate, wash it with saturated brine, dry it, and then evaporate the solvent under reduced pressure to obtain product D; the mass ratio of the product B to the 1,4-diazabicyclo[2.2.2]octane and the 2-mercaptopropionic acid is 7.5:6.7:2.9; the mass ratio of the product C to the hydrochloric acid (calculated as HCl) is 30:7;

[0031] (3) Dissolve the product D in dichloromethane, add a dimethylformamide solution of oxalyl chloride, and stir for reaction at room temperature for 2 h to obtain solution A; simultaneously drip the solution A and a tetrahydrofuran-dichloromethane solution (V / V = 3 / 1) of 1,4-butanediol into a dichloromethane solution of pyridine, stir for reaction for 1 h, remove the precipitate, wash it with 5% hydrochloric acid solution, concentrate it, and then purify it through a silica gel column to remove the unreacted reactants to obtain product E; dissolve the product E in dichloromethane, add m-chloroperoxybenzoic acid under cooling conditions, and stir for reaction at room temperature for 2 h, remove the precipitate, and evaporate the solvent from the supernatant under reduced pressure; the mass ratio of the product D to the oxalyl chloride, the 1,4-butanediol, and the pyridine is 8.3:15.7:3.5:12.3; the mass ratio of the product E to the m-chloroperoxybenzoic acid is 2.8:5;

[0032] The solid content of the polyacrylic acid emulsion is 38 wt%, the polymerization molecular weight is 130,000 - 150,000, and the viscosity is 26 mPa·s;

[0033] The solid content of the polyacrylate emulsion is 41 wt%, the polymerization molecular weight is 130,000 - 150,000, and the viscosity is 37 mPa·s;

[0034] The hydroxyacrylate monomer is a mixture of 2-hydroxy-3-phenoxypropyl acrylate and β-hydroxyethyl methacrylate with an equimolar ratio;

[0035] The lower alcohol solvent is ethanol;

[0036] The pigment is carbon black; the filler is calcium carbonate;

[0037] The initiator is 2-hydroxy-2-methyl-phenylpropanone-1 (1173); the dispersant is dispersant 5040; the defoamer is defoamer byk-028; the pH regulator is organic amine (AMP-95), which is used to control the pH value of the water-based ink, making it stable at 8.0 - 9.5, avoiding too high or too low ink viscosity, and improving printing suitability;

[0038] The preparation method of the gravure printing UV-curable water-based ink includes the following steps:

[0039] S1. Weigh each raw material in proportion for standby;

[0040] S2. Mix the polyacrylic acid emulsion, the polyacrylate emulsion, the hydroxyacrylate monomer, the modified monomer, the aliphatic polyurethane acrylate, the lower alcohol solvent, the initiator and each additive, stir well until completely dissolved, then add the pigment and the filler, continue to stir until evenly dispersed, and grind in a grinding machine to the desired fineness to obtain the gravure printing UV-curable water-based ink.

[0041] Example 2

[0042] A gravure printing UV-curable water-based ink, by weight, comprises the following components: 70 parts of polyacrylic acid emulsion, 30 parts of polyacrylate emulsion, 12 parts of hydroxyacrylate monomer, 6 parts of modified monomer, 10 parts of aliphatic polyurethane acrylate (CAS No.: 68987-79-1), 7 parts of lower alcohol solvent, 6 parts of pigment, 13 parts of filler, 2 parts of initiator, 1 part of dispersant, 0.6 part of defoamer, and 4 parts of pH regulator;

[0043] The preparation method of the modified monomer is the same as that in Example 1;

[0044] The solid content of the polyacrylic acid emulsion is 38 wt%, the polymerization molecular weight is 130,000 - 150,000, and the viscosity is 26 mPa·s;

[0045] The solid content of the polyacrylate emulsion is 41 wt%, the polymerization molecular weight is 130,000 - 150,000, and the viscosity is 37 mPa·s;

[0046] The hydroxyacrylate monomer is a mixture of 2-hydroxy-3-phenoxypropyl acrylate and β-hydroxyethyl methacrylate in an equimolar ratio;

[0047] The lower alcohol solvent is ethanol;

[0048] The pigment is carbon black; the filler is calcium carbonate;

[0049] The initiator is 2-hydroxy-2-methyl-phenylpropanone-1 (1173); the dispersant is dispersant 5040; the defoamer is defoamer byk-028; the pH regulator is organic amine (AMP-95);

[0050] The preparation method of the gravure printing UV-curable waterborne ink is the same as that in Example 1.

[0051] Example 3

[0052] A gravure printing UV-curable waterborne ink, by weight, comprises the following components: 50 parts of polyacrylate emulsion, 50 parts of polyacrylate ester emulsion, 10 parts of hydroxyacrylate monomer, 10 parts of modified monomer, 10 parts of aliphatic polyurethane acrylate (CAS No.: 68987-79-1), 7 parts of lower alcohol solvent, 6 parts of pigment, 13 parts of filler, 2 parts of initiator, 1 part of dispersant, 0.6 part of defoamer, and 3.1 parts of pH regulator;

[0053] The preparation method of the modified monomer is the same as that in Example 1;

[0054] The solid content of the polyacrylate emulsion is 38 wt%, the polymerization molecular weight is 130,000 - 150,000, and the viscosity is 26 mPa·s;

[0055] The solid content of the polyacrylate ester emulsion is 41 wt%, the polymerization molecular weight is 130,000 - 150,000, and the viscosity is 37 mPa·s;

[0056] The hydroxyacrylate monomer is a mixture of 2-hydroxy-3-phenoxypropyl acrylate and β-hydroxyethyl methacrylate in an equimolar ratio;

[0057] The lower alcohol solvent is ethanol;

[0058] The pigment is carbon black; the filler is calcium carbonate;

[0059] The initiator is 2-hydroxy-2-methyl-phenylpropanone-1 (1173); the dispersant is dispersant 5040; the defoamer is defoamer byk-028; the pH regulator is organic amine (AMP-95);

[0060] The preparation method of the gravure printing UV-curable waterborne ink is the same as that in Example 1.

[0061] Example 4

[0062] An intaglio printing UV-curable water-based ink, calculated by weight parts, comprises the following components: 30 parts of polyacrylic acid emulsion, 70 parts of polyacrylate emulsion, 12 parts of hydroxyacrylate monomer, 10 parts of tert-butyl acrylate monomer, 15 parts of aliphatic polyurethane acrylate (CAS No.: 68987-79-1), 7 parts of lower alcohol solvent, 6 parts of pigment, 13 parts of filler, 2 parts of initiator, 1 part of dispersant, 0.6 part of defoamer, 2.2 parts of pH regulator;

[0063] The solid content of the polyacrylic acid emulsion is 38wt%, the polymerization molecular weight is 130,000 - 150,000, and the viscosity is 26mPa·s;

[0064] The solid content of the polyacrylate emulsion is 41wt%, the polymerization molecular weight is 130,000 - 150,000, and the viscosity is 37mPa·s;

[0065] The hydroxyacrylate monomer is a mixture of 2-hydroxy-3-phenoxypropyl acrylate and β-hydroxyethyl methacrylate in an equimolar ratio;

[0066] The lower alcohol solvent is ethanol;

[0067] The pigment is carbon black; the filler is calcium carbonate;

[0068] The initiator is 2-hydroxy-2-methyl-phenylacetone-1 (1173); the dispersant is dispersant 5040; the defoamer is defoamer byk-028; the pH regulator is organic amine (AMP-95);

[0069] The preparation method of the intaglio printing UV-curable water-based ink is the same as that of Example 1.

[0070] The performance of the intaglio printing ink compositions described in Examples 1 - 4 was tested. Among them, the adhesion was tested by the alcohol test method. Take the printed sheet and place it on a clean platform working surface (ink surface facing up); wrap the weight with a cotton cloth and soak the white cotton cloth with an appropriate amount of alcohol; wipe the printed surface with the white cotton cloth soaked with alcohol 10 - 15 times (one round trip is counted as one time); after wiping, check whether there is ink peeling on the printed surface and whether there is ink on the surface of the white cotton cloth. The highest score is 10 points (no obvious ink peeling), and the lowest score is 0 points (ink peeling is greater than 80%); the viscosity was measured using a digital rotational viscometer at a rotational speed of 100rpm (rotor 62#), a temperature of 25°C, and a relative humidity of 65%; for the drying property, 0.125mL of the ink was used to prepare a color spreading sample on an aluminum cardboard, and UV light (lamp power 100W / cm, irradiation energy of 20mJ / (cm 2After the ((first)) irradiation, place the printing surface upward on the flat plate, use the tail of the paper clip to scratch forcefully towards the edge, examine the ink marks in the blank part, and judge the drying degree. The highest score is 10 points (fully cured), and the lowest score is 0 points (cannot be cured); the abrasion resistance refers to GB / T 3008-2008; the stability is to conduct 30 repeated freezing (minus 20 °C) and heating (75 °C) tests on the ink, observe whether there is gelation or reverse coarsening of the ink, and then score according to the ink condition. The highest score is 10 points (almost no change), and the lowest score is 0 points (extremely poor stability); the measurement results are as follows:

[0071]

[0072]

[0073] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than limiting the protection scope of the present invention. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the essence and scope of the technical solutions of the present invention.

Claims

1. An intaglio printing UV-curable water-based ink, characterized in that, By weight parts, it comprises the following components: 100 parts of polyacrylic acid emulsion and / or polyacrylate emulsion, 5 - 18 parts of hydroxyacrylate monomer, 6 - 16 parts of modified monomer, 9 - 20 parts of aliphatic polyurethane acrylate, 5 - 15 parts of lower alcohol solvent, 10 - 30 parts of pigment and filler, 1 - 8 parts of initiator, 1 - 10 parts of auxiliary agent; The preparation method of the modified monomer comprises the following steps: (1) Mix benzaldehyde and tert-butyl acrylate, add a catalyst, stir and react at room temperature for 24 - 48 h. After the reaction is completed, wash successively with hydrochloric acid solution and saturated brine, dry and then distill off the solvent under reduced pressure to obtain product A; dissolve the product A in dichloromethane, add acetic anhydride and N,N-dimethylaminopyridine, stir and react at room temperature for 12 - 20 h. After the reaction is completed, wash successively with hydrochloric acid solution and saturated brine, dry and then distill off the solvent under reduced pressure to obtain product B; (2) Dissolve the product B in tetrahydrofuran, add 1,4-diazabicyclo[2.2.2]octane, stir and mix, then add 2-mercaptopropionic acid and stir and react for 1 - 2 h. Distill off the solvent and then dissolve with ethyl acetate, wash successively with hydrochloric acid solution and saturated brine, dry and then distill off the solvent under reduced pressure to obtain product C; dissolve the product C in dioxane, add hydrochloric acid and heat under reflux at 80 - 100 °C for 1 - 4 h, cool and then dilute with water, extract with ethyl acetate, wash with saturated brine, dry and then distill off the solvent under reduced pressure to obtain product D; (3) Dissolve the product D in dichloromethane, add a solution of oxalyl chloride in dimethylformamide, stir and react at room temperature for 1 - 4 h to obtain solution A; simultaneously drip the solution A and a solution of 1,4-butanediol into a solution of pyridine, stir and react for 1 - 2 h, remove the precipitate, wash with hydrochloric acid solution, concentrate and then purify by column chromatography to obtain product E; dissolve the product E in dichloromethane, add m-chloroperbenzoic acid under cooling conditions, stir and react at room temperature for 1 - 4 h, remove the precipitate, and distill off the solvent from the supernatant under reduced pressure to prepare.

2. The gravure printing UV-curable water-based ink according to claim 1, characterized in that, In step (1), the mass ratio of the benzaldehyde, the tert-butyl acrylate and the catalyst is 1:(1.2 - 1.5):(0.8 - 0.9); the mass ratio of the product A, the acetic anhydride and the N,N-dimethylaminopyridine is 10:(5 - 5.8):(1 - 1.6).

3. A gravure printing UV-curable water-based ink according to claim 1, characterized in that, In step (2), the mass ratio of the product B, the 1,4-diazabicyclo[2.2.2]octane and the 2-mercaptopropionic acid is 1:(0.85 - 1):(0.35 - 0.45); the mass ratio of the product C and the hydrochloric acid is 10:(2 - 3).

4. A gravure printing UV-curable water-based ink according to claim 1, characterized in that In step (3), the mass ratio of the product D, the oxalyl chloride, the 1,4-butanediol and the pyridine is 1:(1.7 - 2.1):(0.35 - 0.5):(1.3 - 1.8); the mass ratio of the product E and the m-chloroperbenzoic acid is 1:(1.5 - 2.2).

5. The gravure printing UV-curable water-based ink according to claim 1, characterized in that, The polymerization molecular weight of the polyacrylic acid emulsion and the polyacrylate emulsion is 100,000 - 150,000, the pH value is 6 - 8, and the solid content is 35 - 45%.

6. The gravure printing UV-curable water-based ink according to claim 1, characterized in that, The hydroxyacrylate monomer is one or more of 2 - hydroxy - 3 - phenoxypropyl acrylate, β - hydroxyethyl methacrylate, β - hydroxypropyl acrylate, and β - hydroxypropyl methacrylate.

7. A gravure printing UV-curable water-based ink according to claim 1, characterized in that, The pigment and filler include pigments and fillers. The pigments are one or more of phthalocyanine pigments, carbon black, and titanium white; the fillers are one or more of matting powder, talc powder, calcium carbonate, and silicon dioxide.

8. A gravure printing UV-curable water-based ink according to claim 1, characterized in that, The initiator is one or more of 1 - hydroxy - cyclohexyl benzophenone, 2,4,6 - trimethylbenzoyl - diphenylphosphine oxide, 2 - hydroxy - 2 - methyl - phenylacetone - 1, 2,4,6 - trimethylbenzoyl - ethoxy - phenylphosphine oxide, and 2 - hydroxy - 2 - methyl - p - hydroxyethyl ether - phenylacetone - 1.

9. The gravure printing UV-curable aqueous ink according to claim 1, characterized in that, The additives are one or more of dispersants, emulsifiers, stabilizers, softeners, preservatives, defoamers, pH regulators, adhesion promoters, antistatic agents, thickeners, and light absorbers.

10. A method for preparing a gravure printing UV-curable aqueous ink according to any one of claims 1-9, characterized in that, It includes the following steps: S1. Weigh each raw material in proportion for standby. S2. Mix the polyacrylic acid emulsion and / or polyacrylate emulsion, the hydroxyacrylate monomer, the modified monomer, the aliphatic polyurethane acrylate, the lower alcohol solvent, the initiator, and the additives, and stir well until completely dissolved. Then add the pigment and filler, continue to stir until evenly dispersed, and grind in a grinding machine to the desired fineness to obtain the gravure printing UV - curable water - based ink.

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