Preparation process of water-based gravure ink

Abstract

The invention relates to the technical field of water-based gravure ink, in particular to a preparation process of water-based gravure ink. The existing technical problems of high environmental load, poor wettability and sewage generation of water-based gravure ink are solved. The preparation method comprises the following steps: carrying out polymerization cross-linking reaction on a water-based acrylic polymer and a hydrophilic caprylic capric triglyceride monomer mixture to obtain a cross-linked emulsion; the preparation method comprises the following steps: carrying out mixing dispersion treatment on a disperse dye, the emulsion, an organic solvent, a surfactant, deionized water and an auxiliary agent, grinding, filtering, and introducing a modified polyether composition to obtain the water-based gravure ink. The fineness of the water-based gravure ink is lt; the glossiness is 0.5 mu m and the glossiness is gt; the tinting strength is 100%, and the adhesion fastness is 99%; the VOC content is 0%; the storage stability is 4 years; the surface tension is 15mN / m; in the preparation process, the COD (Chemical Oxygen Demand) of the wastewater is 2mg / L, and the chromaticity is 1 degree.

Description

Technical Field

[0001] The invention relates to the technical field of water-based gravure ink, in particular to a preparation process of water-based gravure ink. Background Art

[0002] As one of the four major printing methods, gravure printing is mainly used in publishing, packaging, building materials decoration, clothing printing and other fields. The gravure products have rich layering and bright ink colors, which truly reflect the original image and make them increasingly popular. At present, the continuous operation of rotary gravure technology has been widely used in the field of electronic component printing with its simple mechanical process and fewer control variables. The realization of the ink transfer process depends on the extrusion and mutual rotation between the printing roller and the plate roller. The extrusion between the printing roller and the plate roller acts on the ink, changing the flow state of the ink. At the same time, the ink also has a certain reaction force on the printing roller, causing the rubber layer of the printing roller to deform to a certain extent, thereby changing the ink channel width between the two rollers and affecting the ink transfer. To achieve high-quality printing, it is necessary to ensure the stability, uniformity and appropriate transfer amount of the ink.

[0003] Patent CN101284965B discloses a water-based gravure ink equivalent to engraving gravure ink and its application, the ink contains (A) pigment or dye accounting for 0-55% of the total composition of the ink, (B) environmentally friendly water-soluble polymer and polymer monomer binder accounting for 10-90% of the total composition of the ink, (C) environmentally friendly water-soluble cosolvent accounting for 0.5-75% of the total composition of the ink, (D) film-forming aid, neutralizer, foaming agent, expander, ultraviolet absorber, wax accounting for 0.1-52% of the total composition of the ink. The advantages of the ink are non-toxic and tasteless, non-flammable, soluble in water, no harm to the environment and human body, fast drying, the concave and convex effect of the print (ink) of the printed matter obtained by the gravure printing technology can achieve the effect of engraving gravure printing, the printed matter has clear ink layers and strong three-dimensional sense, and the sewage generated in the process of engraving gravure printing is completely eradicated, and no pollution is caused to the environment. However, there are still problems of alkali resistance, acetic acid resistance, water resistance, poor glossiness and poor adhesion to varying degrees.

[0004] Patent CN102516845B discloses a plastic gravure water-based ink, which includes 50-60 parts of deionized water-soluble resin oil, 10-30 parts of pigment, 10-20 parts of deionized water, and 1-8 parts of additives consisting of active agent, defoamer, stabilizer, dispersant, leveling agent, and slip agent. It is environmentally friendly, safe, non-toxic, harmless, non-flammable and non-explosive, and has almost no volatile organic gas, and does not pollute the atmospheric environment; it greatly reduces the residual pollutants on the surface of printed products, and meets food hygiene and safety; it has strong adhesion, rubbing resistance, scratch resistance, high gloss, good wear resistance, and fast drying speed; in its production process, the exhaust gas discharged from the reactor is purified by deionized water spraying to meet the emission standards. However, it has not yet involved the reduction of VOC and the reduction of CO 2 , the environmental load has not decreased.

[0005] Patent CN107922763B discloses a water-based gravure ink, which contains a pigment, a polymer, a water-soluble organic solvent, a surfactant and deionized water. The boiling point of the water-soluble organic solvent is above 100°C and below 260°C. The water-based gravure ink contains a water-soluble organic solvent of 10% by mass or more and 35% by mass or less, and contains water of 50% by mass or more and 70% by mass or less, and contains the surfactant of 0.01% by mass or more and 5.0% by mass or less. The invention prepares a water-based gravure ink with low environmental load, high-precision printing through excellent brightness suitability and excellent drying property, but the total amount of the water-soluble organic solvent is limited. When the ink dries, it is mostly water volatilization at first. Once the water in the dispersion medium is reduced, the charge repulsion of the dispersion will be significantly reduced, and the ink stability will be reduced.

[0006] Patent CN109996848B discloses a water-based gravure ink, which is made of pigment, polymer, water-soluble organic solvent, surfactant and deionized water; wherein the surfactant is an acetylene glycol surfactant, which has less environmental load and can be used for high-precision printing with excellent leveling properties. The water-based gravure ink does not need to be diluted with a solvent during printing, and the total amount of the water-soluble organic solvent contained in the ink is 15% of the ink composition, which is not easy to become a source of VOC, and can reduce the environmental load. With the goal of reducing VOC, water-based inks that do not use organic solvents or replace organic solvents with high-boiling point solvents that are not easy to become a source of VOCs, when printing on a printing substrate with low deionized water absorption such as a resin film, the ink has insufficient wetting and expansion on the printing substrate, resulting in a decrease in printing concentration and a decrease in drying after printing.

[0007] Patent CN112204110B discloses a water-based gravure ink, which contains a water-soluble organic solvent of glycol ether with a boiling point of 100°C to 260°C, a mass of 1% to 10% and a deionized water content of 50% to 80% by mass. The ink will not dry in the mesh of the gravure and can maintain a high transfer rate. In addition, in a system with a large content of deionized water, glycol ethers and specific silicone surfactants are contained. When the deionized water of the ink after transfer evaporates and the concentration of glycol ether increases, wettability can be maintained, and convection in the ink can be suppressed, thereby not hindering the wettability and expansibility of the ink on the printed substrate. The ink has a small environmental load and excellent printing concentration and dryness. However, sewage is generated during the preparation of the water-based gravure ink, which pollutes the environment; therefore, the existing technical problem is that the water-based gravure ink has a large environmental load, poor wettability, and produces sewage.

[0008] Therefore, a preparation process of water-based gravure ink is proposed. Summary of the invention

[0009] The object of the present invention is to provide a preparation process of water-based gravure ink. The present invention performs polymerization cross-linking reaction through a monomer mixture to obtain an emulsion; disperse dyes, the emulsion, an organic solvent, a surfactant, deionized water and an auxiliary agent are mixed and dispersed, ground and filtered, and a modified polyether composition is introduced to obtain a preparation process of a water-based gravure ink to solve the technical problems of high environmental load, poor wettability and sewage generation of water-based gravure ink. The prepared water-based gravure ink has a fineness of <0.5 μm, a glossiness of >90%, a tinting power of 100%, an adhesion fastness of 99%, a VOC content of 0%, a storage stability of 4 years, a surface tension of 15 mN / m, a COD of 2 mg / L and a chromaticity of 1° in the preparation process of the wastewater; the kinematic viscosity of the water-based gravure ink prepared by the present invention is 19 s, the gravure printing speed is 180 m / min, the printing efficiency is high, the watermark saturation is good, the layers are clear, the three-dimensional sense of the image and text is strong, and the anti-counterfeiting effect is good.

[0010] To achieve the above object, the present invention provides the following technical solutions:

[0011] A preparation process of a water-based gravure ink, the preparation process of the water-based gravure ink comprising the following steps:

[0012] S1 is calculated by weight, 24-35 parts of water-based acrylic polymer, 28-37 parts of hydrophilic caprylic acid glyceride, and 0.5-3 parts of emulsifier are added to 7.5-10 parts of deionized water, stirred and emulsified to obtain an emulsion; 11-21 parts of casein solution are added to the emulsion, 3-8 parts of alkaline co-solvent are added dropwise, the temperature is raised to 60-90° C., 8-11 parts of N-vinyl pyrrolidone, 1-3 parts of acrylonitrile, 0.3-1.5 parts of trimethylolpropane triacrylate are added dropwise, and 0.3-1 parts of initiator are added dropwise to carry out polymerization reaction to obtain a polymer; 2-6.8 parts of amino polystyrene microspheres as a crosslinking agent are added to the polymer to carry out crosslinking reaction to obtain a crosslinked emulsion;

[0013] S2: 10-18 parts of disperse dye, 0.1-1 parts of sodium methylene dinaphthalene sulfonate, 35-60 parts of the cross-linked emulsion, 6.5 parts of organic solvent, 1-2 parts of surfactant and 5.5-7.5 parts of deionized water are mixed and dispersed at a stirring speed of 800-1500 r / min, and ground and filtered to obtain an aqueous cross-linked emulsion;

[0014] S3: 26-39 parts of the aqueous cross-linked emulsion, 0.3-1.5 parts of octadecyl alcohol polyoxyethylene ether, 0.3-1.5 parts of 1,2-pentanediol, 0.1-0.5 parts of the modified polyether composition, 4.5-5.5 parts of deionized water and 0.3-1.5 parts of the auxiliary agent are mixed and stirred to obtain an aqueous gravure ink.

[0015] Preferably, the emulsifier is one of sodium alkyl sulfonate, sodium vinyl sulfonate, and alkylphenol polyoxyethylene ether.

[0016] Preferably, the alkaline co-solvent is one of borax, ethanolamine, triethanolamine and sodium silicate.

[0017] Preferably, the initiator is one of peroxides, azobisisobutyronitrile and persulfates.

[0018] Preferably, the particle size of the cross-linking agent amino polystyrene microspheres is 0.05-0.5 μm.

[0019] Preferably, the organic solvent is a mixed solvent of water, alcohol and alcohol ether.

[0020] Preferably, the surfactant is a silicone surfactant or an acetylene glycol surfactant.

[0021] Preferably, the auxiliary agent is one or more of 0.1-0.5 parts of an aqueous active agent, 0.1-0.4 parts of an aqueous dispersant, 0.5-1.5 parts of an aqueous lubricant, and 0.1-1.5 parts of an aqueous pH regulator.

[0022] Preferably, the preparation method of the modified polyether composition is to mix and disperse the "H-type" silicone polyether, acetylene alcohol polyether, and linear silicone polyether by stirring as follows:

[0023] At 27±2°C, add "H-type" silicone polyether, acetylene alcohol polyether, and linear silicone polyether into a vacuum reaction vessel, add silica while stirring at a speed of 300-1000r / min until the dispersed particle size of the silica is less than 1μm, and reduce the rotation speed to 100-200r / min.

[0024] A preparation process of a water-based gravure ink, the water-based gravure ink comprising the disperse dye, the water-based cross-linked emulsion, the organic solvent, the surfactant, the modified polyether composition, the octadecyl alcohol polyoxyethylene ether, the 1,2-pentanediol, the deionized water and the auxiliary agent; the water-based gravure ink has a fineness of less than 0.5 μm, a glossiness of more than 90%, a tinting power of 100%, and an adhesion fastness of 99%; the VOC content of the water-based gravure ink is 0%; the storage stability of the water-based gravure ink is 4 years; the surface tension of the water-based gravure ink is 15 mN / m; and the COD of wastewater in the preparation process of the water-based gravure ink is 2 mg / L, and the chromaticity is 1°.

[0025] Compared with the prior art, the present invention has the following beneficial effects:

[0026] 1. The present invention uses environmentally friendly, non-toxic casein with good adhesion as a connecting material, introduces N-vinyl pyrrolidone, acrylonitrile, and trimethylolpropane triacrylate for modification, and uses it together with octadecyl alcohol polyoxyethylene ether and 1,2-pentanediol; the introduction of triacrylate functional groups allows the polymer to form a three-dimensional network structure; the adhesion is increased, and the adhesion fastness is 99%.

[0027] 2. The organic solvent of the present invention contains water, and does not need to be diluted with a solution during printing. The use of acetylene glycol surfactants is not likely to become a source of VOC, thereby reducing VOC emissions, reducing VOC emissions to 0%, and reducing environmental load.

[0028] 3. The hydrophilic caprylic acid glyceride of the present invention has the dual characteristics of hydrophilicity and lipophilicity, is an emulsifier, has the functions of dispersing, wetting and emulsifying, and is not affected by pH, so the stability is relatively strong; the aqueous acrylic polymer solution also has good hydrophilicity, so that the aqueous gravure ink has good stability. These two components used for the aqueous gravure ink can make the aqueous gravure ink have good stability, and the storage stability is 4 years.

[0029] 4. The present invention uses amino polystyrene microspheres as a crosslinking agent in the preparation process of the water-based acrylic polymer crosslinked aqueous dispersion, thereby reducing the surface tension difference between the aqueous system and the surface of the substrate; because the surface tension is high in the ink with water as the main component without containing a low-boiling point solvent, water, alcohol and alcohol ether are used as a mixed solvent, and a modified polyether composition is used to play the role of a defoaming agent, so that the foam is controlled to an acceptable level, the surface tension is low, the surface tension is 15mN / m, and the wettability is good.

[0030] 5. The disperse dye used in the present invention has sublimation characteristics, sublimates at 150-230°C, and is mixed with a binder to form ink. The wastewater generated in the process is tested for wastewater quality. The COD in the wastewater is 2 mg / L, the chromaticity is 1°, no sewage is generated, and it is environmentally friendly and safe. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 The present invention is a process flow chart of the preparation of water-based gravure ink. DETAILED DESCRIPTION

[0032] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0033] The reagents or instruments used in the examples without indicating the manufacturer can be purchased from commercial sources.

[0034] The casein solution of the present invention, CAS: 9000-71-9;

[0035] The N-vinyl pyrrolidone of the present invention, CAS: 88-12-0;

[0036] The acrylonitrile described in the present invention, CAS: 107-13-1;

[0037] The trimethylolpropane triacrylate of the present invention has a CAS number of 15625-89-5.

[0038] The amino polystyrene microspheres of the present invention, CAS: 9003-53-6;

[0039] The 1,2-pentanediol of the present invention, CAS: 5343-92-0;

[0040] See also Figure 1 The present invention provides a preparation process of a water-based gravure ink, and the technical scheme is as follows:

[0041] Example 1

[0042] S1 is calculated by weight: 15 parts of casein solution, 5 parts of borax are added dropwise, the temperature is raised to 60-90°C, 9 parts of N-vinyl pyrrolidone, 2 parts of acrylonitrile, 1 part of trimethylolpropane triacrylate are added dropwise, and 0.7 parts of benzoyl peroxide are added dropwise to carry out polymerization reaction to obtain a polymer; 4 parts of amino polystyrene microspheres as a crosslinking agent are added to the polymer to carry out crosslinking reaction to obtain a crosslinked emulsion;

[0043] S2: 15 parts of the dye, 40 parts of the cross-linked emulsion and 6.5 parts of deionized water are mixed and dispersed at a stirring speed of 1000 r / min, and ground and filtered to obtain an aqueous cross-linked emulsion;

[0044] S3: 35 parts of the aqueous cross-linked emulsion, 1.2 parts of octadecyl alcohol polyoxyethylene ether, 1.4 parts of 1,2-pentanediol, 5 parts of deionized water and 1.2 parts of an auxiliary agent are mixed and stirred to obtain an aqueous gravure ink.

[0045] Examples 2-16 refer to the preparation methods and parameter conditions of Example 1, with the differences shown in Table 1.

[0046] Table 1 Types of alkaline cosolvents and initiators in Examples 2-16

[0047]

[0048] Comparative Example 1

[0049] The preparation method and parameter conditions are the same as those in Example 1, except that trimethylolpropane triacrylate is not added for dispersion in step S1.

[0050] Example 17 Physical Properties Test of Water-Based Gravure Ink

[0051] The physical parameters and test basis of the physical properties test of the water-based gravure ink of Comparative Example 1 and Examples 1-16 are as follows: fineness test is based on GB / T13217.3-2008; gloss test is based on GB / T13217.2-2009; tinting strength test is based on GB / T13217.6-2008; adhesion fastness is based on GB / T13217.7-2009. The relevant test results are shown in Table 2.

[0052] Table 2 Physical property test results of Examples 1-16 and Comparative Example 1

[0053] Fineness / μm Glossiness / % Tinting strength / % Adhesion fastness / % Example 1 <0.5 >80 96 95 Example 2 <0.5 >80 98 95 Example 3 <0.5 >90 100 99 Example 4 <0.5 >89 99 93 Example 5 <0.5 >80 99 94 Example 6 <0.5 >75 98 90 Example 7 <0.5 >80 95 94 Example 8 <0.5 >80 97 92 Example 9 <0.5 >70 99 93 Example 10 <0.5 >84 97 93 Embodiment 11 <0.5 >80 98 94 Example 12 <0.5 >80 99 95 Embodiment 13 <0.5 >79 96 95 Embodiment 14 <0.5 >80 97 97 Embodiment 15 <0.5 >82 97 96 Example 16 <0.5 >84 98 97 Comparative Example 1 <35.0 >40 55 65

[0054] Comparative Example 1 without trimethylolpropane triacrylate dispersion is inferior to Examples 1-16 in terms of the physical parameter test results of fineness, glossiness, tinting strength and adhesion fastness. Examples 1-16 add crosslinking agent amino polystyrene microspheres with a particle size of 0.05-0.5 μm, which reduces the fineness of the obtained water-based gravure ink. In addition, trimethylolpropane triacrylate is added for dispersion modification, and the introduction of triacrylate functional groups causes the polymer to form a three-dimensional network structure, which increases adhesion; in addition, the use of different types of alkaline cosolvents and initiators has inconsistent effects on increasing adhesion; from Table 2, it is found that the glossiness, tinting strength and adhesion fastness of Example 3 are higher than those of other examples. The fineness of the water-based gravure ink prepared in Example 3 is <0.5 μm, the glossiness is >90%, the tinting strength is 100%, the adhesion fastness is 99%, and the adhesion is significantly increased.

[0055] Embodiment 18

[0056] Refer to the preparation method and parameter conditions of Example 3, except as listed in Table 3.

[0057] Comparative Example 2

[0058] The preparation method and parameter conditions are the same as those in Example 3, except that 1 part of an organosilicon defoamer is added to the mixture in step S3.

[0059] Example 38 VOC Test of Water-Based Gravure Ink

[0060] The VOC content of the wastewater generated during the preparation process of the aqueous gravure inks of Comparative Example 2 and Examples 3 and 18-37 was tested using a thermal desorption (TD) device and a gas chromatography / mass spectrometry method (GC / MS) or a chromatography / flame ionization detection method (GC / FID). The types, amounts and VOC contents of the surfactants of Examples 3, 18-37 and Comparative Example 2 are shown in Table 3.

[0061] Table 3 Surfactant types, dosages and VOC contents of Examples 3, 18-37 and Comparative Example 2

[0062]

[0063]

[0064] Compared with the organosilicon defoamer used in Comparative Example 2, when silicone surfactants or acetylene glycol surfactants are used in Examples 18-37, the VOC content in the preparation process is lower when the amount of surfactant is the same. The national standard GB38507-2020 "Limits on the Content of Volatile Organic Compounds (VOCs) in Ink" stipulates that the VOC content of water-based gravure ink is ≤30%; it can be seen that the VOC content in the water-based gravure ink prepared in Comparative Example 2 is 70%, which exceeds the limit; while silicone surfactants or acetylene glycol surfactants are used in Examples 18-37, both of which are non-toluene surfactants, which reduce the emission of VOC, and the VOC content in the water-based gravure ink prepared in Examples 18-37 is lower than the limit; in addition, surfactants of different concentrations have different effects; in Examples 18-37, Example 19 uses acetylene glycol surfactants to minimize VOC emissions, and the VOC content is 0%, because the preparation process of Example 19 uses aqueous solvents without dilution, and the environmental load is reduced.

[0065] Embodiment 39

[0066] S1 is calculated by weight, 24 parts of water-based acrylic polymer, 28 parts of hydrophilic caprylic acid glyceride, and 2 parts of sodium alkyl sulfonate are added to 9 parts of deionized water, stirred and emulsified to obtain an emulsion; 15 parts of casein solution are added to the emulsion, 5 parts of borax are added dropwise, the temperature is raised to 60-90°C, 9 parts of N-vinyl pyrrolidone, 2 parts of acrylonitrile, and 1 part of trimethylolpropane triacrylate are added dropwise, and 0.7 parts of benzoyl peroxide are added dropwise to carry out polymerization reaction to obtain a polymer; 4 parts of amino polystyrene microspheres as a crosslinking agent are added to the polymer for crosslinking reaction to obtain a crosslinked emulsion;

[0067] S2: 15 parts of the dye, 40 parts of the emulsion, 2 parts of the acetylene glycol surfactant and 6.5 parts of deionized water are mixed and dispersed at a stirring speed of 1000 r / min, and ground and filtered to obtain an aqueous cross-linked emulsion;

[0068] S3: 35 parts of the aqueous cross-linked emulsion, 1.2 parts of octadecyl alcohol polyoxyethylene ether, 1.4 parts of 1,2-pentanediol, 5 parts of deionized water and 1.2 parts of an auxiliary agent are mixed and stirred to obtain an aqueous gravure ink.

[0069] Examples 40-47

[0070] Referring to the preparation method and parameter conditions of Example 39, the differences are shown in Table 5.

[0071] Example 48 Storage stability test of water-based gravure ink

[0072] The storage stability technical performance of the water-based gravure ink prepared in Examples 39-47 was tested by sampling. The parameter conditions and test results of Examples 39-47 are shown in Table 4.

[0073] Table 4 Parameter conditions and test results of Examples 39-47

[0074]

[0075]

[0076] Hydrophilic caprylic decanoic acid glyceride has the dual characteristics of hydrophilicity and lipophilicity, is a kind of emulsifier, has the functions of dispersing, wetting and emulsifying, and this emulsifier is not affected by pH, so the stability is relatively strong; the aqueous acrylic polymer solution also has good hydrophilicity, so that the aqueous gravure ink has good stability, and the addition of the two is conducive to the improvement of the stability of the aqueous gravure ink. As can be seen from Table 4, when the aqueous acrylic polymer is 35 parts, the hydrophilic caprylic decanoic acid glyceride is 37 parts, and the alkylphenol polyoxyethylene ether is 2 parts in Example 47, the storage stability is optimal, which is 4 years.

[0077] Embodiment 48

[0078] S1 is calculated by weight: 35 parts of water-based acrylic polymer, 37 parts of hydrophilic caprylic acid glyceride, and 2 parts of alkylphenol polyoxyethylene ether are added to 9 parts of deionized water, stirred and emulsified to obtain an emulsion; 15 parts of casein solution are added to the emulsion, 5 parts of borax are added dropwise, the temperature is raised to 60-90°C, 9 parts of N-vinyl pyrrolidone, 2 parts of acrylonitrile, and 1 part of trimethylolpropane triacrylate are added dropwise, and 0.7 parts of benzoyl peroxide are added dropwise to carry out polymerization reaction to obtain a polymer; 4 parts of amino polystyrene microspheres as a crosslinking agent are added to the polymer for crosslinking reaction to obtain a crosslinked emulsion;

[0079] S2: 15 parts of dye, 40 parts of the cross-linked emulsion, 6.5 parts of water, alcohol and alcohol ether as a mixed solvent, 2 parts of acetylene glycol surfactant and 6.5 parts of deionized water are mixed and dispersed at a stirring speed of 1000 r / min, ground and filtered to obtain an aqueous cross-linked emulsion;

[0080] S3: At 27±2°C, add "H-type" silicon polyether, acetylene alcohol polyether and linear silicon polyether into a vacuum reaction vessel, add silicon dioxide while stirring at a speed of 300 r / min until the dispersed particle size of silicon dioxide is less than 1 μm, reduce the rotation speed to 100 r / min, and obtain a modified polyether composition.

[0081] S4: 35 parts of the aqueous cross-linked emulsion, 1.2 parts of octadecyl alcohol polyoxyethylene ether, 1.4 parts of 1,2-pentanediol, 0.3 parts of the modified polyether composition, 5 parts of deionized water and 1.2 parts of the auxiliary agent are mixed and stirred to obtain an aqueous gravure ink.

[0082] Examples 49-55

[0083] Referring to the preparation method and parameter conditions of Example 48, the differences are shown in Table 6.

[0084] Comparative Example 3

[0085] Refer to the preparation method and parameter conditions of Example 47, except that in step S2, water, alcohol and alcohol ether are used as the mixed solvent and isopropanol is used instead.

[0086] Example 56 Surface tension test of water-based gravure ink

[0087] At 25°C, the surface tension was tested using a surface tension meter using a pull-ring method. The parameter conditions and surface tension test results of Examples 47-55 and Comparative Example 4 are shown in Table 6;

[0088] Table 6 Parameter conditions and surface tension test results of Examples 47-55 and Comparative Example 4

[0089]

[0090] As can be seen from Table 6, Example 47 is an ink with water as the main component and no low-boiling point solvent, and the surface tension is high; Comparative Example 3 is an aqueous ink with isopropyl alcohol as the organic solvent, and the surface tension is reduced, but the printing process needs to be diluted with a solution to reduce the environmental load; so in Examples 48-55, Example 51 uses water, alcohol and alcohol ether as a mixed solvent, and uses a modified polyether composition to act as a defoamer to control the foam to an acceptable level, with a lower surface tension and better wettability; the stirring speed of the modified polyether composition synthesized in Example 51 is 1000r / min, the reduction speed is 100r / min, the surface tension is 15mN / m, and the wettability is good.

[0091] Embodiment 56

[0092] S1 is calculated by weight: 35 parts of water-based acrylic polymer, 37 parts of hydrophilic caprylic acid glyceride, and 2 parts of alkylphenol polyoxyethylene ether are added to 9 parts of deionized water, stirred and emulsified to obtain an emulsion; 15 parts of casein solution are added to the emulsion, 5 parts of borax are added dropwise, the temperature is raised to 60-90°C, 9 parts of N-vinyl pyrrolidone, 2 parts of acrylonitrile, and 1 part of trimethylolpropane triacrylate are added dropwise, and 0.7 parts of benzoyl peroxide are added dropwise to carry out polymerization reaction to obtain a polymer; 4 parts of amino polystyrene microspheres as a crosslinking agent are added to the polymer for crosslinking reaction to obtain a crosslinked emulsion;

[0093] S2: 10 parts of disperse dye, 0.1 parts of sodium methylene dinaphthalene sulfonate, 40 parts of the emulsion, 6.5 parts of water, alcohol and alcohol ether as a mixed solvent, 2 parts of acetylene glycol surfactant and 6.5 parts of deionized water are mixed and dispersed, the stirring speed is 1000r / min, and the mixture is ground and filtered to obtain an aqueous emulsion;

[0094] S3: At 27±2°C, add "H-type" silicone polyether, acetylene alcohol polyether and linear silicone polyether into a vacuum reaction vessel, add silica while stirring at a speed of 1000 r / min until the dispersed particle size of the silica is less than 1 μm, and reduce the rotation speed to 100 r / min to obtain a modified polyether composition.

[0095] S4: 35 parts of the aqueous cross-linked emulsion, 1.2 parts of octadecyl alcohol polyoxyethylene ether, 1.4 parts of 1,2-pentanediol, 0.3 parts of the modified polyether composition, 5 parts of deionized water and 1.2 parts of the auxiliary agent are mixed and stirred to obtain an aqueous gravure ink.

[0096] Examples 57-64

[0097] Refer to the preparation method and parameter conditions of Example 56, the differences are shown in Table 7.

[0098] Table 7 The dosage of disperse dyes and sodium methylene dinaphthalene sulfonate in Examples 56-64

[0099]

[0100] Example 65 Water Quality Test of Wastewater Generated from the Water-Based Gravure Ink Preparation Process

[0101] According to the second level of Comprehensive Wastewater Discharge Standard GB8978-1996, the main pollutant is COD. The water quality test of the wastewater generated by the preparation process of the water-based gravure ink of Examples 50, 56-64 mainly measures the content and color of COD. The test results are shown in Table 8.

[0102] Table 8 Test results of wastewater quality of Examples 50, 56-64

[0103]

[0104]

[0105] Wastewater is generated during the preparation of water-based ink. If it is detected that the wastewater does not meet the discharge standard, it is necessary to perform biochemical treatment on the wastewater to meet the discharge standard. The components of water-based ink mainly include pigments, which generally have good dispersibility. They enter the wastewater during the flushing process of the printing equipment, causing the wastewater to have a high chromaticity and be difficult to remove directly. Therefore, disperse dyes are used, which have sublimation characteristics and sublimate at 150-230°C. They are mixed with a binder to make ink. The wastewater COD generated during Example 64 is 2 mg / L, the chromaticity is 1°, and almost no wastewater is generated. It can meet the discharge standard without biochemical treatment.

[0106] Example 65 Kinematic viscosity of water-based gravure ink and performance test for gravure printing

[0107] Examples 3, 19, 46, 50, 64 The kinematic viscosity test method is to detect the viscosity of the liquid flow, leaving a small hole at the center of the bottom of a cup, and connecting a very long handle to both ends of the cup. The Zahn cup is immersed in the liquid to be tested and filled, and then lifted from the liquid to be tested, and the outflow time of the liquid to be tested is calculated.

[0108] The kinematic viscosity of the water-based gravure ink and the performance test for gravure printing are shown in Table 9.

[0109] Table 9 Kinematic viscosity of Examples 3, 19, 47, 51, 64 and performance test for gravure printing

[0110]

[0111]

[0112] As can be seen from Table 9, among Examples 3, 19, 47, 51, and 64, the kinematic viscosity of the water-based gravure ink of Example 64 is 19s, the gravure printing speed is 180m / min, the printing efficiency is high, the watermark saturation is good, the layers are clear, the three-dimensional sense of the image and text is strong, and the anti-counterfeiting effect is good.

[0113] In summary, a preparation process of a water-based gravure ink of the present invention is to obtain a cross-linked emulsion by polymerizing and cross-linking a water-based acrylic acid polymer and a hydrophilic octanoic acid glyceride monomer mixture; a disperse dye, the cross-linked emulsion, an organic solvent, a surfactant, deionized water and an auxiliary agent are mixed and dispersed, ground and filtered, and a modified polyether composition is introduced to obtain a water-based gravure ink. The fineness of the water-based gravure ink prepared by the present invention is <0.5μm, the glossiness is >90%, the tinting power is 100%, the adhesion fastness is 99%; the VOC content is 0%; the storage stability is 4 years; the surface tension is 15mN / m; the COD of the wastewater in the preparation process is 2mg / L, and the chromaticity is 1°; the water-based gravure ink prepared by the present invention has a kinematic viscosity of 19s, a gravure printing speed of 180m / min, high printing efficiency, good watermark saturation, clear layers, strong three-dimensional sense of pictures and texts, and good anti-counterfeiting effect, which solves the technical problems of high environmental load, poor wettability and sewage generation of water-based gravure ink.

[0114] Although embodiments of the present invention have been shown and described, it will be appreciated by those skilled in the art that various changes, modifications, substitutions and variations may be made to the embodiments without departing from the principles and spirit of the present invention, and that the scope of the present invention is defined by the appended claims and their equivalents.

Claims

1. A process for preparing a water-based gravure ink, characterized in that: The preparation process of the water-based gravure ink comprises the following steps: S1 is calculated by weight, 24-35 parts of water-based acrylic polymer, 28-37 parts of hydrophilic caprylic acid glyceride, and 0.5-3 parts of emulsifier are added to 7.5-10 parts of deionized water, stirred and emulsified to obtain an emulsion; 11-21 parts of casein solution are added to the emulsion, 3-8 parts of alkaline co-solvent are added dropwise, the temperature is raised to 60-90° C., 8-11 parts of N-vinyl pyrrolidone, 1-3 parts of acrylonitrile, 0.3-1.5 parts of trimethylolpropane triacrylate are added dropwise, and 0.3-1 parts of initiator are added dropwise to carry out polymerization reaction to obtain a polymer; 2-6.8 parts of amino polystyrene microspheres as a crosslinking agent are added to the polymer to carry out crosslinking reaction to obtain a crosslinked emulsion; S2: 10-18 parts of disperse dye, 0.1-1 parts of sodium methylene dinaphthalene sulfonate, 35-60 parts of the cross-linked emulsion, 6.5 parts of organic solvent, 1-2 parts of surfactant and 5.5-7.5 parts of deionized water are mixed and dispersed at a stirring speed of 800-1500 r / min, and ground and filtered to obtain an aqueous cross-linked emulsion; S3: 26-39 parts of the aqueous cross-linked emulsion, 0.3-1.5 parts of octadecyl alcohol polyoxyethylene ether, 0.3-1.5 parts of 1,2-pentanediol, 0.1-0.5 parts of the modified polyether composition, 4.5-5.5 parts of deionized water and 0.3-1.5 parts of the auxiliary agent are mixed and stirred to obtain an aqueous gravure ink.

2. The process for preparing a water-based gravure ink according to claim 1, characterized in that: The emulsifier is one of sodium alkyl sulfonate, sodium vinyl sulfonate and alkylphenol polyoxyethylene ether.

3. The process for preparing a water-based gravure ink according to claim 1, characterized in that: The alkaline co-solvent is one of borax, ethanolamine, triethanolamine and sodium silicate.

4. The process for preparing a water-based gravure ink according to claim 1, characterized in that: The initiator is one of peroxides, azobisisobutyronitrile and persulfate.

5. The process for preparing a water-based gravure ink according to claim 1, characterized in that: The particle size of the cross-linking agent amino polystyrene microspheres is 0.05-0.5 μm.

6. The process for preparing a water-based gravure ink according to claim 1, characterized in that: The organic solvent is a mixed solvent of water, alcohol and alcohol ether.

7. The process for preparing a water-based gravure ink according to claim 1, characterized in that: The surfactant is a silicone surfactant or an acetylene glycol surfactant.

8. The process for preparing a water-based gravure ink according to claim 1, characterized in that: The auxiliary agent is one or more of 0.1-0.5 parts of an aqueous active agent, 0.1-0.4 parts of an aqueous dispersant, 0.5-1.5 parts of an aqueous lubricant, and 0.1-1.5 parts of an aqueous pH regulator.

9. The process for preparing a water-based gravure ink according to claim 8, characterized in that: The preparation method of the modified polyether composition is to mix, stir and disperse "H-type" silicone polyether, acetylene alcohol polyether and linear silicone polyether.

10. The process for preparing a water-based gravure ink according to claim 1, characterized in that: The water-based gravure ink comprises the disperse dye, the water-based cross-linked emulsion, the organic solvent, the surfactant, the modified polyether composition, the octadecyl alcohol polyoxyethylene ether, the 1,2-pentanediol, the deionized water and the auxiliary agent; the water-based gravure ink is prepared by the preparation process according to any one of claims 1 to 9; the water-based gravure ink has a fineness of <0.5 μm, a glossiness of >90%, a tinting strength of 100%, and an adhesion fastness of 99%; the VOC content of the water-based gravure ink is 0%; and the storage stability of the water-based gravure ink is 4 years; The surface tension of the water-based gravure ink is 15 mN / m; The COD of wastewater in the process of preparing the water-based gravure ink is 2 mg / L, and the chromaticity is 1°.

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