Aqueous intaglio printing ink and a method for its preparation

Abstract

The present application relates to the technical field of ink, in particular to a kind of water-based gravure printing ink and preparation method thereof.The ink is composed of modified acrylic resin dispersion, phthalocyanine blue pigment, deionized water, anhydrous ethanol, polyethylene wax dispersion, ammonia and 2-amino-2-methyl-1-propanol, etc.The innovation lies in that a modified acrylic resin with front-stage rich-hydroxyl and rear-stage rich-carboxyl chain segment structure is constructed through three-stage sequential polymerization process.The design, combined with segmented neutralization process and specific additives, synergistically solves the problem that dispersion stability, light mesh transferability, adhesion, water wiping resistance and composite strength are difficult to be considered in the prior art, and is especially suitable for plastic film printing.

Description

Technical Field

[0001] This invention relates to the field of ink technology, and in particular to a water-based gravure printing ink and its preparation method. Background Technology

[0002] Water-based gravure printing inks have attracted much attention in the field of plastic film packaging printing due to their environmentally friendly characteristics. However, compared with solvent-based inks, the application of water-based systems on non-absorbent plastic substrates faces many technical challenges. The core contradiction lies in the difficulty of balancing the ink's stable dispersibility, printability (such as shallow halftone transfer), and the final ink film performance (such as adhesion, water resistance, and composite strength).

[0003] To improve the performance of water-based inks on plastic films, current technologies often employ a strategy of increasing the resin's acid value and supplementing it with excess amines for neutralization, thereby enhancing the resin's water dispersibility and stability. However, this approach directly leads to an increase in residual hydrophilic ammonium carboxylate salts after film formation, severely impairing the ink film's water resistance and abrasion resistance. Furthermore, high-acid-value resins themselves may also adversely affect adhesives in subsequent lamination processes, weakening the long-term stability of the composite interface.

[0004] To address these contradictions, some technical solutions involve introducing alkali-soluble rosin resin, polyurethane resin, or epoxy-modified resin into the formulation. While introducing rosin resin can improve pigment wetting and initial drying, its brittleness and poor weather resistance can impair ink film flexibility and long-term durability. Introducing polyurethane resin can enhance adhesion and flexibility, but may lead to significantly increased costs, compatibility issues with acrylic resins, and potential impacts on resolubility. Epoxy modification may introduce new curing requirements or storage stability risks. These added components, while attempting to compensate for a particular performance deficiency, often introduce new problems or fail to fundamentally reconcile the conflicts between different performance requirements.

[0005] At the level of neutralization and film formation mechanisms, traditional one-step neutralization processes struggle to precisely control the phase transition of resin particles from an aqueous dispersion to a dense ink film. Simple neutralization methods can lead to non-uniform particle morphology, and the distribution and migration behavior of carboxyl groups during drying cannot be optimized, thus affecting the resin's anchoring to the substrate and the formation of cohesive strength in the ink film. Particularly for pigment dispersion processes requiring high-speed grinding, the lack of targeted interface restabilization methods easily leads to decreased system stability after grinding, manifested as significant viscosity changes and increased fineness after ink storage.

[0006] Therefore, developing a novel water-based gravure printing ink that can achieve synergistic improvements in multiple properties such as dispersion stability, printing transferability, film adhesion, water resistance, and subsequent composite strength without relying on high-acid-value resins or complex external resin systems, through innovative resin structure design and preparation processes, has become a pressing technical challenge in this field. Summary of the Invention

[0007] In view of this, the purpose of this invention is to provide a water-based gravure printing ink and its preparation method, so as to solve the problem that in the prior art, water-based gravure printing inks are difficult to simultaneously achieve excellent dispersion stability, shallow screen transfer, adhesion, water wiping resistance and interface stability after lamination on plastic films without relying on high acid value or added functional resins.

[0008] To achieve the above objectives, the present invention provides an aqueous gravure printing ink, comprising, by weight, the following raw materials: 695-720 parts modified acrylic resin dispersion, 220 parts phthalocyanine blue pigment, 648.8-694.2 parts deionized water, 105-130 parts anhydrous ethanol, 35-45 parts polyethylene wax dispersion, 0.8-1.2 parts ammonia water with a weight fraction of 25%, and 2.5-3.8 parts 2-amino-2-methyl-1-propanol; Furthermore, the modified acrylic resin dispersion is prepared by sequentially solution polymerizing a first monomer mixture, a second monomer mixture, and a third monomer mixture, followed by adding water to reduce viscosity, neutralizing with ammonia, and adding deionized water for dispersion. Preferably, by mass parts, the first monomer mixture consists of 170-190 parts butyl acrylate, 160-180 parts methyl methacrylate, 125-160 parts isobornyl methacrylate, 66-88 parts 2-hydroxyethyl methacrylate, 4-6 parts methacrylic acid, and 4 parts tert-dodecyl mercaptan; the second monomer mixture consists of 40-50 parts butyl acrylate, 45-55 parts methyl methacrylate, 20-25 parts isobornyl methacrylate, 16-22 parts 2-hydroxyethyl methacrylate, 8-10 parts methacrylic acid, and 1 part tert-dodecyl mercaptan; and the third monomer mixture consists of 80-100 parts butyl acrylate, 115-130 parts methyl methacrylate, 15-20 parts 2-hydroxyethyl methacrylate, 22-40 parts acrylic acid, 18-26 parts methacrylic acid, and 1 part tert-dodecyl mercaptan.

[0009] Furthermore, by weight, the raw materials of the water-based gravure printing ink also include 6 parts wetting and dispersing agent, 3 parts defoamer, and 1.8-2.2 parts substrate wetting agent.

[0010] Preferably, the wetting and dispersing agent is BYK-193; the defoamer is BYK-016; and the substrate wetting agent is BYK-DYNWET 810.

[0011] Preferably, the modified acrylic resin dispersion has an acid value of 40-54 mgKOH / g, a hydroxyl value of 43-53 mgKOH / g, and a number-average molecular weight of 13500-17500 for the solid resin.

[0012] Preferably, the modified acrylic resin dispersion has a solid content of 45.2%-47.4% and a pH of 7.4-8.0 at 25°C.

[0013] Preferably, the polyethylene wax dispersion is of type HORDAMER PE 35.

[0014] Furthermore, the present invention also provides a method for preparing water-based gravure printing ink, comprising the following steps: S1. Preparation of modified acrylic resin dispersion: The first monomer mixture, the second monomer mixture and the third monomer mixture are sequentially subjected to solution polymerization. Then, deionized water is added to reduce viscosity, ammonia is added for the first neutralization, and deionized water is added to disperse the mixture to obtain the modified acrylic resin dispersion. S2. Preparation of grinding slurry: Mix a portion of modified acrylic resin dispersion, phthalocyanine blue pigment, deionized water, anhydrous ethanol, wetting and dispersing agent and a portion of defoamer, then pre-disperse and mill to obtain grinding slurry; S3. Preparation of water-based gravure printing ink: After cooling the grinding slurry, add a diluent made of 25% ammonia and deionized water for a second neutralization and replenishment. Then add the remaining modified acrylic resin dispersion, deionized water, polyethylene wax dispersion, substrate wetting agent, remaining defoamer, anhydrous ethanol and 2-amino-2-methyl-1-propanol, stir, filter and mature to obtain water-based gravure printing ink.

[0015] Preferably, in step S1, the sequential solution polymerization uses azobisisobutyronitrile as the initiator and 1-methoxy-2-propanol and anhydrous ethanol as solvents.

[0016] Preferably, in step S2, the amount of modified acrylic resin dispersion added is 55wt%-65wt% of the total amount added; the amount of defoamer added is 60wt%-70wt% of the total amount added.

[0017] Preferably, in step S2, the grinding process uses zirconia beads with a diameter of 1 mm and is carried out at 1800 rpm for 75-85 minutes, while controlling the material temperature to be no higher than 40°C.

[0018] Preferably, in step S3, filtration is performed using a 300-mesh filter, and maturation is carried out at 25°C for 12 hours.

[0019] The beneficial effects of this invention are: This invention constructs a modified acrylic resin with a segmental sequence structure through a specific monomer combination and a three-stage sequential polymerization process. In this structure, the front-end segments are relatively rich in hydroxyl groups, while the rear-end segments are relatively rich in carboxyl groups. This design allows the carboxyl-rich segments to preferentially and effectively undertake anchoring and stabilizing functions in the aqueous phase, ensuring the storage stability of the resin dispersion and the interfacial stability of the pigment dispersion. During the drying and film-forming process, the front-end hydroxyl-rich segments more readily interact with the substrate to form a dense film structure, thereby achieving excellent adhesion and water-resistant abrasion resistance even at moderate acid values.

[0020] The segmented neutralization strategy employed in this invention significantly optimizes the resin's phase transition process. Pre-addition of water before the first ammonia neutralization reduces the system viscosity, ensuring a uniform neutralization reaction and preventing localized gelation, thus laying the foundation for a dispersion with uniform particle size and excellent stability. The second ammonia replenishment, performed after the pigment grinding process, promptly repairs the impact of grinding on the resin-pigment interface and re-stabilizes the dispersion system, which is crucial for maintaining the ink's light-screen transfer performance. The final addition of 2-amino-2-methyl-1-propanol, which evaporates more slowly than ammonia, provides a continuous pH buffer during ink curing and storage, further ensuring the system's long-term stability.

[0021] This invention introduces a polyethylene wax dispersion as an abrasion-resistant component into the formulation. This component can migrate to the surface during film formation, effectively improving the smoothness of the ink film surface. Furthermore, because it is added in dispersion form and is carefully selected, it has minimal interference with the adhesion interface between the resin and the substrate. Therefore, while significantly improving abrasion resistance, it also maintains good adhesion of the ink film to the plastic film and subsequent lamination strength. In summary, the technical solution of this invention achieves a good balance of various ink properties through resin structure design, polymerization process, neutralization sequence, and the synergy of functional additives. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to specific embodiments.

[0023] Example 1: Step 1: Add 185g butyl acrylate, 170g methyl methacrylate, 135g isobornyl methacrylate, 80g 2-hydroxyethyl methacrylate, 5g methacrylic acid, and 4g tert-dodecyl mercaptan to a container and stir at room temperature for 15 minutes to obtain the first monomer mixture; then stir 45g butyl acrylate, 50g methyl methacrylate, 20g isobornyl methacrylate, 20g 2-hydroxyethyl methacrylate, 10g methacrylic acid, and 1g tert-dodecyl mercaptan until homogeneous to obtain the second monomer mixture; then stir 90g butyl acrylate, 120g methyl methacrylate, 20g 2-hydroxyethyl methacrylate, 30g acrylic acid, 20g methacrylic acid, and 1g tert-dodecyl mercaptan until homogeneous to obtain the third monomer mixture. Subsequently, 5g of azobisisobutyronitrile was dissolved in 35g of 1-methoxy-2-propanol and 20g of anhydrous ethanol to obtain the first initiator solution; 4g of azobisisobutyronitrile was dissolved in 25g of 1-methoxy-2-propanol and 10g of anhydrous ethanol to obtain the second initiator solution; and 2g of azobisisobutyronitrile was dissolved in 10g of 1-methoxy-2-propanol and 10g of anhydrous ethanol to obtain the second initiator solution. Step 2: Add 110g of [something] to a four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen inlet. 1-Methoxy-2-propanol and 20g anhydrous ethanol were stirred at 300rpm and nitrogen was introduced for 30min. The temperature was then raised to 84℃. At 84℃, 58g of the first monomer mixture and 12g of the first initiator solution were added first, and the mixture was kept at this temperature for 10min to form a seed polymerization segment. Then, at 84℃, the remaining 517g of the first monomer mixture and the remaining 48g of the first initiator solution were added dropwise over 90min. After the addition was completed, the temperature was maintained for another 40min. While maintaining the reaction temperature at 84℃, 145g of the second monomer mixture and 15g of the second initiator solution were added dropwise over 35min. After the addition was completed, the temperature was maintained for another 20min. While maintaining the temperature at 84℃, 280g of the third monomer mixture and the remaining 24g of the second initiator solution were added dropwise over 50min. After the addition was completed, the temperature was maintained for another 45min. Then, 22g of the second initiator solution was added, and the temperature was maintained for another 30min. The temperature was then lowered to 62℃, and the stirring speed was increased to 700rpm. First, add 100g of deionized water within 10 minutes to reduce the viscosity of the system and avoid localized rapid neutralization. Then, pre-mix 26g of 25% ammonia water with 40g of deionized water evenly and add it dropwise over 20 minutes. After the addition is complete, continue to keep warm for 20 minutes. Subsequently, add 180g, 200g, 200g, and 200g of deionized water in sequence, each time controlled at 10 minutes. After each addition, continue to keep warm for 10 minutes. After all additions are completed, keep warm for another 30 minutes and then cool down to 35℃. Filter through a 200-mesh nylon mesh and mature at 25℃ for 12 hours to obtain a modified acrylic resin dispersion. The dispersion has an acid value of 46mgKOH / g and a hydroxyl value of 50mgKOH / g based on solid resin. The number average molecular weight is 15000, the solid content is 46%, and the pH is 7.6 at 25℃, as determined by gel permeation chromatography calibrated with polystyrene standard. Step 3: Take 420g of modified acrylic resin dispersion, 220g of phthalocyanine blue pigment FASTOGEN BLUE LA5380, 170g of deionized water, 40g of anhydrous ethanol, 6g of wetting and dispersing agent BYK-193 and 2g of defoamer BYK-016. First, pre-disperse them in a high-speed disperser at 1500rpm for 20min, then transfer them to a conventional horizontal sand mill, add 1mm diameter zirconia beads, and sand mill at 1800rpm for 80min, controlling the material temperature not to exceed 40℃ to obtain the grinding slurry. Step 4: Cool the grinding slurry to below 35°C, add a diluent made of 1g of 25% ammonia and 9g of deionized water, and stir at 500rpm for 15min; then add 280g of modified acrylic resin dispersion, 200g of deionized water and 40g of polyethylene wax dispersion HORDAMER PE 35, and stir at 600rpm for 15min; then add 2g of substrate wetting agent BYK-DYNWET 810, 1g of defoamer BYK-016, 300g of deionized water and 80g of anhydrous ethanol, and continue stirring for 15min; finally add 3g of multifunctional additive AMP-95, and continue stirring for 20min. Filter through a 300-mesh filter and age at 25°C for 12h to obtain water-based gravure printing ink.

[0024] Example 2: Step 1: Add 170g butyl acrylate, 180g methyl methacrylate, 150g isobornyl methacrylate, 70g 2-hydroxyethyl methacrylate, 6g methacrylic acid, and 4g tert-dodecyl mercaptan to a container and stir at room temperature for 15 minutes to obtain the first monomer mixture; then stir 40g butyl acrylate, 55g methyl methacrylate, 25g isobornyl methacrylate, 18g 2-hydroxyethyl methacrylate, 9g methacrylic acid, and 1g tert-dodecyl mercaptan until homogeneous to obtain the second monomer mixture; then stir 85g butyl acrylate, 130g methyl methacrylate, 18g 2-hydroxyethyl methacrylate, 26g acrylic acid, 18g methacrylic acid, and 1g tert-dodecyl mercaptan until homogeneous to obtain the third monomer mixture. Subsequently, 5g of azobisisobutyronitrile was dissolved in 35g of 1-methoxy-2-propanol and 20g of anhydrous ethanol to obtain the first initiator solution; 4g of azobisisobutyronitrile was dissolved in 25g of 1-methoxy-2-propanol and 10g of anhydrous ethanol to obtain the second initiator solution; and 2g of azobisisobutyronitrile was dissolved in 10g of 1-methoxy-2-propanol and 10g of anhydrous ethanol to obtain the second initiator solution. Step 2: Add 110g of [something] to a four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen inlet. 1-Methoxy-2-propanol and 20g anhydrous ethanol were stirred at 300rpm and nitrogen was introduced for 30min. The temperature was then raised to 84℃. At 84℃, 60g of the first monomer mixture and 12g of the first initiator solution were added, and the mixture was kept at this temperature for 12min to form a seed polymerization segment. Then, at 84℃, the remaining 520g of the first monomer mixture and the remaining 48g of the first initiator solution were added dropwise over 95min. After the addition was completed, the temperature was maintained for another 35min. While maintaining the reaction temperature at 84℃, 148g of the second monomer mixture and 15g of the second initiator solution were added dropwise over 35min. After the addition was completed, the temperature was maintained for another 20min. While maintaining the temperature at 84℃, 278g of the third monomer mixture and the remaining 24g of the second initiator solution were added dropwise over 48min. After the addition was completed, the temperature was maintained for another 40min. Then, 22g of the second initiator solution was added, and the temperature was maintained for another 30min. The temperature was then lowered to 62℃, and the stirring speed was increased to 700rpm. First, 110g of deionized water was added within 10 minutes to reduce the viscosity of the system and avoid localized rapid neutralization. Then, 24g of 25% ammonia water and 40g of deionized water were premixed and added dropwise over 20 minutes. After the addition was completed, the temperature was maintained for another 20 minutes. Subsequently, 170g, 190g, 190g, and 190g of deionized water were added sequentially, with each addition time controlled at 10 minutes. After each addition, the temperature was maintained for another 10 minutes. After all the additions were completed, the temperature was maintained for another 30 minutes and then cooled to 35°C. The mixture was filtered through a 200-mesh nylon mesh and aged at 25°C for 12 hours to obtain a modified acrylic resin dispersion. The dispersion had an acid value of 40mgKOH / g and a hydroxyl value of 45mgKOH / g based on solid resin. The number-average molecular weight was 13500, the solid content was 45.2%, and the pH was 7.4 at 25°C, as determined by gel permeation chromatography calibrated with polystyrene standard. Step 3: Take 425g of modified acrylic resin dispersion, 220g of phthalocyanine blue pigment FASTOGEN BLUE LA5380, 165g of deionized water, 45g of anhydrous ethanol, 6g of wetting and dispersing agent BYK-193 and 2g of defoamer BYK-016. First, pre-disperse them in a high-speed disperser at 1500rpm for 20min, then transfer them to a conventional horizontal sand mill, add 1mm diameter zirconia beads, and sand mill at 1800rpm for 75min, controlling the material temperature not to exceed 40℃ to obtain the grinding slurry. Step 4: Cool the grinding slurry to below 35°C, add a diluent made of 0.8g of 25% ammonia and 9.2g of deionized water, and stir at 500rpm for 15min; then add 275g of modified acrylic resin dispersion, 205g of deionized water and 35g of polyethylene wax dispersion HORDAMER PE 35, and stir at 600rpm for 15min; then add 1.8g of substrate wetting agent BYK-DYNWET 810, 1g of defoamer BYK-016, 310g of deionized water and 85g of anhydrous ethanol, and continue stirring for 15min; finally add 3.5g of 2-amino-2-methyl-1-propanol, and continue stirring for 20min. Filter through a 300-mesh filter and age at 25°C for 12h to obtain water-based gravure printing ink.

[0025] Example 3: Step 1: Add 190g butyl acrylate, 160g methyl methacrylate, 125g isobornyl methacrylate, 88g 2-hydroxyethyl methacrylate, 5g methacrylic acid, and 4g tert-dodecyl mercaptan to a container and stir at room temperature for 15 minutes to obtain the first monomer mixture; then stir 50g butyl acrylate, 45g methyl methacrylate, 20g isobornyl methacrylate, 22g 2-hydroxyethyl methacrylate, 10g methacrylic acid, and 1g tert-dodecyl mercaptan until homogeneous to obtain the second monomer mixture; then stir 100g butyl acrylate, 115g methyl methacrylate, 15g 2-hydroxyethyl methacrylate, 35g acrylic acid, 20g methacrylic acid, and 1g tert-dodecyl mercaptan until homogeneous to obtain the third monomer mixture. Subsequently, 5g of azobisisobutyronitrile was dissolved in 35g of 1-methoxy-2-propanol and 20g of anhydrous ethanol to obtain the first initiator solution; 4g of azobisisobutyronitrile was dissolved in 25g of 1-methoxy-2-propanol and 10g of anhydrous ethanol to obtain the second initiator solution; and 2g of azobisisobutyronitrile was dissolved in 10g of 1-methoxy-2-propanol and 10g of anhydrous ethanol to obtain the second initiator solution. Step 2: Add 110g of [something] to a four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen inlet. 1-Methoxy-2-propanol and 20g anhydrous ethanol were stirred at 300rpm and nitrogen gas was introduced for 30min. The temperature was then raised to 84℃. At 84℃, 58g of the first monomer mixture and 12g of the first initiator solution were added first, and the mixture was kept at this temperature for 10min to form a seed polymerization segment. Then, at 84℃, the remaining 514g of the first monomer mixture and the remaining 48g of the first initiator solution were added dropwise over 90min. After the addition was completed, the temperature was maintained for another 40min. While maintaining the reaction temperature at 84℃, 148g of the second monomer mixture and 15g of the second initiator solution were added dropwise over 38min. After the addition was completed, the temperature was maintained for another 20min. While maintaining the temperature at 84℃, 286g of the third monomer mixture and the remaining 24g of the second initiator solution were added dropwise over 55min. After the addition was completed, the temperature was maintained for another 45min. Then, 22g of the second initiator solution was added, and the temperature was maintained for another 30min. The temperature was then lowered to 62℃, and the stirring speed was increased to 700rpm. First, 100g of deionized water was added within 10 minutes to reduce the viscosity of the system and avoid localized rapid neutralization. Then, 28g of 25% ammonia water and 40g of deionized water were premixed evenly and added dropwise over 20 minutes. After the addition was completed, the temperature was maintained for another 20 minutes. Subsequently, 180g, 200g, 210g, and 210g of deionized water were added sequentially, with each addition time controlled at 10 minutes. After each addition, the temperature was maintained for another 10 minutes. After all the additions were completed, the temperature was maintained for another 30 minutes and then cooled to 35°C. The mixture was filtered through a 200-mesh nylon mesh and aged at 25°C for 12 hours to obtain a modified acrylic resin dispersion. The dispersion had an acid value of 50mgKOH / g and a hydroxyl value of 53mgKOH / g based on solid resin. The number-average molecular weight was 16500, the solid content was 46.4%, and the pH was 7.8 at 25°C, as determined by gel permeation chromatography calibrated with polystyrene standard. Step 3: Take 430g of modified acrylic resin dispersion, 220g of phthalocyanine blue pigment FASTOGEN BLUE LA5380, 160g of deionized water, 40g of anhydrous ethanol, 6g of wetting and dispersing agent BYK-193 and 2g of defoamer BYK-016. First, pre-disperse them in a high-speed disperser at 1500rpm for 20min, then transfer them to a conventional horizontal sand mill, add 1mm diameter zirconia beads, and sand mill at 1800rpm for 85min, controlling the material temperature not to exceed 40℃ to obtain the grinding slurry. Step 4: Cool the grinding slurry to below 35°C, add a diluent made of 1.2g of 25% ammonia and 8.8g of deionized water, and stir at 500rpm for 15min; then add 290g of modified acrylic resin dispersion, 190g of deionized water and 40g of polyethylene wax dispersion HORDAMER PE 35, and stir at 600rpm for 15min; then add 2.2g of substrate wetting agent BYK-DYNWET 810, 1g of defoamer BYK-016, 290g of deionized water and 75g of anhydrous ethanol, and continue stirring for 15min; finally add 2.8g of 2-amino-2-methyl-1-propanol, and continue stirring for 20min. Filter through a 300-mesh filter and age at 25°C for 12h to obtain water-based gravure printing ink.

[0026] Example 4: Step 1: Add 180g butyl acrylate, 175g methyl methacrylate, 138g isobornyl methacrylate, 72g 2-hydroxyethyl methacrylate, 5g methacrylic acid, and 4g tert-dodecyl mercaptan to a container and stir at room temperature for 15 minutes to obtain the first monomer mixture; then stir 45g butyl acrylate, 50g methyl methacrylate, 22g isobornyl methacrylate, 20g 2-hydroxyethyl methacrylate, 10g methacrylic acid, and 1g tert-dodecyl mercaptan until homogeneous to obtain the second monomer mixture; then stir 80g butyl acrylate, 125g methyl methacrylate, 18g 2-hydroxyethyl methacrylate, 40g acrylic acid, 20g methacrylic acid, and 1g tert-dodecyl mercaptan until homogeneous to obtain the third monomer mixture. Subsequently, 5g of azobisisobutyronitrile was dissolved in 35g of 1-methoxy-2-propanol and 20g of anhydrous ethanol to obtain the first initiator solution; 4g of azobisisobutyronitrile was dissolved in 25g of 1-methoxy-2-propanol and 10g of anhydrous ethanol to obtain the second initiator solution; and 2g of azobisisobutyronitrile was dissolved in 10g of 1-methoxy-2-propanol and 10g of anhydrous ethanol to obtain the second initiator solution. Step 2: Add 110g of [something] to a four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen inlet. 1-Methoxy-2-propanol and 20g anhydrous ethanol were stirred at 300rpm and nitrogen gas was introduced for 30min. The temperature was then raised to 84℃. At 84℃, 60g of the first monomer mixture and 12g of the first initiator solution were added first, and the mixture was kept at this temperature for 10min to form a seed polymerization segment. Then, at 84℃, the remaining 514g of the first monomer mixture and the remaining 48g of the first initiator solution were added dropwise over 92min. After the addition was completed, the temperature was maintained for another 35min. While maintaining the reaction temperature at 84℃, 148g of the second monomer mixture and 15g of the second initiator solution were added dropwise over 35min. After the addition was completed, the temperature was maintained for another 20min. While maintaining the temperature at 84℃, 284g of the third monomer mixture and the remaining 24g of the second initiator solution were added dropwise over 52min. After the addition was completed, the temperature was maintained for another 45min. Then, 22g of the second initiator solution was added, and the temperature was maintained for another 30min. The temperature was then lowered to 62℃, and the stirring speed was increased to 700rpm. First, 105g of deionized water was added within 10 minutes to reduce the viscosity of the system and avoid localized rapid neutralization. Then, 30g of 25% ammonia water and 45g of deionized water were premixed and added dropwise over 20 minutes. After the addition was completed, the temperature was maintained for another 20 minutes. Subsequently, 175g, 195g, 200g, and 200g of deionized water were added sequentially, with each addition time controlled at 10 minutes. After each addition, the temperature was maintained for another 10 minutes. After all the additions were completed, the temperature was maintained for another 30 minutes and then cooled to 35°C. The mixture was filtered through a 200-mesh nylon mesh and aged at 25°C for 12 hours to obtain a modified acrylic resin dispersion. The dispersion had an acid value of 54mgKOH / g and a hydroxyl value of 47mgKOH / g based on solid resin. The number-average molecular weight was 17500, the solid content was 46.9%, and the pH was 8.0 at 25°C, as determined by gel permeation chromatography calibrated with polystyrene standard. Step 3: Take 420g of modified acrylic resin dispersion, 220g of phthalocyanine blue pigment FASTOGEN BLUE LA5380, 170g of deionized water, 40g of anhydrous ethanol, 6g of wetting and dispersing agent BYK-193 and 2g of defoamer BYK-016. First, pre-disperse them in a high-speed disperser at 1500rpm for 20min, then transfer them to a conventional horizontal sand mill, add 1mm diameter zirconia beads, and sand mill at 1800rpm for 80min, controlling the material temperature not to exceed 40℃ to obtain the grinding slurry. Step 4: Cool the grinding slurry to below 35°C, add a diluent made of 1.0g of 25% ammonia and 9.0g of deionized water, and stir at 500rpm for 15min; then add 280g of modified acrylic resin dispersion, 200g of deionized water and 40g of polyethylene wax dispersion HORDAMER PE 35, and stir at 600rpm for 15min; then add 2.0g of substrate wetting agent BYK-DYNWET 810, 1g of defoamer BYK-016, 300g of deionized water and 80g of anhydrous ethanol, and continue stirring for 15min; finally add 3.8g of 2-amino-2-methyl-1-propanol, and continue stirring for 20min. Filter through a 300-mesh filter and age at 25°C for 12h to obtain water-based gravure printing ink.

[0027] Example 5: Step 1: Add 175g butyl acrylate, 170g methyl methacrylate, 160g isobornyl methacrylate, 66g 2-hydroxyethyl methacrylate, 4g methacrylic acid, and 4g tert-dodecyl mercaptan to a container and stir at room temperature for 15 minutes to obtain the first monomer mixture; then stir 45g butyl acrylate, 55g methyl methacrylate, 20g isobornyl methacrylate, 16g 2-hydroxyethyl methacrylate, 8g methacrylic acid, and 1g tert-dodecyl mercaptan until homogeneous to obtain the second monomer mixture; then stir 90g butyl acrylate, 125g methyl methacrylate, 18g 2-hydroxyethyl methacrylate, 22g acrylic acid, 26g methacrylic acid, and 1g tert-dodecyl mercaptan until homogeneous to obtain the third monomer mixture. Subsequently, 5g of azobisisobutyronitrile was dissolved in 35g of 1-methoxy-2-propanol and 20g of anhydrous ethanol to obtain the first initiator solution; 4g of azobisisobutyronitrile was dissolved in 25g of 1-methoxy-2-propanol and 10g of anhydrous ethanol to obtain the second initiator solution; and 2g of azobisisobutyronitrile was dissolved in 10g of 1-methoxy-2-propanol and 10g of anhydrous ethanol to obtain the second initiator solution. Step 2: Add 110g of [something] to a four-necked flask equipped with a mechanical stirrer, thermometer, reflux condenser, dropping funnel, and nitrogen inlet. 1-Methoxy-2-propanol and 20g anhydrous ethanol were stirred at 300rpm and nitrogen was introduced for 30min. The temperature was then raised to 84℃. At 84℃, 58g of the first monomer mixture and 12g of the first initiator solution were added first, and the mixture was kept at this temperature for 10min to form a seed polymerization segment. Then, at 84℃, the remaining 521g of the first monomer mixture and the remaining 48g of the first initiator solution were added dropwise over 95min. After the addition was completed, the temperature was maintained for another 40min. While maintaining the reaction temperature at 84℃, 145g of the second monomer mixture and 15g of the second initiator solution were added dropwise over 34min. After the addition was completed, the temperature was maintained for another 20min. While maintaining the temperature at 84℃, 282g of the third monomer mixture and the remaining 24g of the second initiator solution were added dropwise over 48min. After the addition was completed, the temperature was maintained for another 40min. Then, 22g of the second initiator solution was added, and the temperature was maintained for another 30min. The temperature was then lowered to 62℃, and the stirring speed was increased to 700rpm. First, 95g of deionized water was added within 10 minutes to reduce the viscosity of the system and avoid localized rapid neutralization. Then, 23g of 25% ammonia water and 40g of deionized water were premixed evenly and added dropwise over 20 minutes. After the addition was completed, the temperature was maintained for another 20 minutes. Subsequently, 170g, 190g, 200g, and 200g of deionized water were added sequentially, with each addition time controlled at 10 minutes. After each addition, the temperature was maintained for another 10 minutes. After all the additions were completed, the temperature was maintained for another 30 minutes and then cooled to 35°C. The mixture was filtered through a 200-mesh nylon mesh and aged at 25°C for 12 hours to obtain a modified acrylic resin dispersion. The dispersion had an acid value of 41mgKOH / g and a hydroxyl value of 43mgKOH / g based on solid resin. The number-average molecular weight was 14500, the solid content was 47.4%, and the pH was 7.5 at 25°C, as determined by gel permeation chromatography calibrated with polystyrene standard. Step 3: Take 425g of modified acrylic resin dispersion, 220g of phthalocyanine blue pigment FASTOGEN BLUE LA5380, 170g of deionized water, 35g of anhydrous ethanol, 6g of wetting and dispersing agent BYK-193 and 2g of defoamer BYK-016. First, pre-disperse them in a high-speed disperser at 1500rpm for 20min, then transfer them to a conventional horizontal sand mill, add 1mm diameter zirconia beads, and sand mill at 1800rpm for 78min, controlling the material temperature not to exceed 40℃ to obtain the grinding slurry. Step 4: Cool the grinding slurry to below 35°C, add a diluent made of 0.8g of 25% ammonia and 9.2g of deionized water, and stir at 500rpm for 15min; then add 275g of modified acrylic resin dispersion, 190g of deionized water and 45g of polyethylene wax dispersion HORDAMER PE 35, and stir at 600rpm for 15min; then add 1.8g of substrate wetting agent BYK-DYNWET 810, 1g of defoamer BYK-016, 295g of deionized water and 70g of anhydrous ethanol, and continue stirring for 15min; finally add 2.5g of 2-amino-2-methyl-1-propanol, and continue stirring for 20min. Filter through a 300-mesh filter and age at 25°C for 12h to obtain water-based gravure printing ink.

[0028] Comparative Example 1:

[0029] The difference from Example 1 is as follows: In step one, the first monomer mixture, the second monomer mixture, and the third monomer mixture are pre-mixed evenly and used as the same monomer material; in step two, 58g of the pre-mixed monomer material and 12g of the first initiator solution are added at 84°C, and after keeping warm for 10min, the remaining 948g of the pre-mixed monomer material, the remaining 48g of the first initiator solution, and all 35g of the second initiator solution are simultaneously added dropwise over 175min. After the dropwise addition is completed, the temperature is kept warm for another 105min, and then 22g of the additional initiator solution is added and kept warm for another 30min; the remaining conditions are the same as in Example 1.

[0030] Comparative Example 2: The difference from Example 1 is as follows: In step one, the first monomer mixture is adjusted to contain 185g butyl acrylate, 160g methyl methacrylate, 135g isoborneol methacrylate, 80g 2-hydroxyethyl methacrylate, 15g methacrylic acid, and 4g tert-dodecyl mercaptan; the second monomer mixture is adjusted to contain 45g butyl acrylate, 40g methyl methacrylate, 20g isoborneol methacrylate, 20g 2-hydroxyethyl methacrylate, 20g methacrylic acid, and 1g tert-dodecyl mercaptan; the third monomer mixture is adjusted to contain 90g butyl acrylate, 140g methyl methacrylate, 20g 2-hydroxyethyl methacrylate, 20g acrylic acid, 10g methacrylic acid, and 1g tert-dodecyl mercaptan, so that the acidic monomers are more evenly distributed in the three monomer mixtures, and the carboxyl-rich composition of the third monomer mixture is no longer formed; the remaining conditions are the same as in Example 1.

[0031] Comparative Example 3: The difference from Example 1 is that in step two, after cooling to 62°C, instead of adding 100g of deionized water within 10 minutes to reduce the viscosity of the system, 26g of ammonia water with a mass fraction of 25% and 40g of deionized water are directly added dropwise to the system within 20 minutes; the other conditions are the same as in Example 1.

[0032] Comparative Example 4: The difference from Example 1 is that in step four, the diluent prepared by 1g of 25% ammonia and 9g of deionized water is no longer added, and the 1g of 25% ammonia is incorporated into the first ammonia pre-neutralization in step two, so that the amount of 25% ammonia added in step two is adjusted from 26g to 27g. In step four, a second ammonia replenishment neutralization is no longer performed; the other conditions are the same as in Example 1.

[0033] Comparative Example 5: The difference from Example 1 is that in step four, instead of adding 3g of 2-amino-2-methyl-1-propanol, 2.2g of ammonia water with a mass fraction of 25% and 0.8g of deionized water are added to make the total amount added at the end and the alkali equivalent basically the same; the other conditions are the same as in Example 1.

[0034] Comparative Example 6: The difference from Example 1 is that in step four, instead of adding 40g of polyethylene wax dispersion HORDAMER PE 35, 40g of deionized water is used to make up the same amount; the other conditions are the same as in Example 1.

[0035] Performance testing: Sample preparation process: The inks obtained in Examples 1-5 and Comparative Examples 1-6 were filtered through a 300-mesh filter and then left to stand for 24 hours at 23±2℃ and 50±5% relative humidity. 12μm polyethylene terephthalate film and 20μm biaxially oriented polypropylene film treated with corona discharge were selected as printing substrates, with the surface tension of both substrates controlled at 38-40 mN / m. Printing was performed using a laboratory gravure proofing machine with a printing roller line count of 250 lines / inch, a cell depth of 28μm, a squeegee angle of 65°, a printing speed of 120m / min, and three drying tunnel temperatures of 50℃, 60℃, and 70℃, with a dwell time of 2 seconds for each tunnel. The dry film thickness after printing was controlled at 1.2±0.1μm. Samples used for adhesion, water wiping resistance, rubbing fastness, and shallow screen transfer tests were all tested after being placed at 23±2℃ for 24 hours following printing. For the composite strength test, the printed 12μm polyethylene terephthalate film was placed at 23±2℃ for 24 hours, and then laminated with a 60μm cast polypropylene film using solvent-free polyurethane adhesive, with the adhesive application amount controlled at 2.5±0.2 g / m². 2The bonding temperature was 55℃, the composite pressure was 0.35MPa, and the curing conditions were 40℃×48h. After that, the samples were cut and tested.

[0036] Intrinsic characterization of modified acrylic resin dispersions: Samples were taken in accordance with GB / T 3186-2006, and the acid value, hydroxyl value, number-average molecular weight, average particle size and pH of the modified acrylic resin dispersions obtained in step two of Examples 1-5 and Comparative Examples 1-6 were determined respectively. Acid value was determined by titration with potassium hydroxide ethanol standard solution according to GB / T 6743-2008, with the sample weight controlled at 0.50±0.01g; hydroxyl value was determined by titration according to GB / T 31412-2015, with the sample weight controlled at 1.00±0.02g; number-average molecular weight was determined by gel permeation chromatography according to GB / T 27810-2011, using tetrahydrofuran as the mobile phase, a flow rate of 1.0mL / min, a column temperature of 35℃, and correction using polystyrene standard sample; average particle size was determined by dynamic light scattering according to GB / T 29022-2021, with the sample diluted with deionized water to a solid content of 0.05%, equilibrated at 25℃ for 5min, and tested three times consecutively, with the average value taken; pH was determined directly at 25℃ according to GB / T8325-1987.

[0037] Ink viscosity and fineness: The inks obtained in Step 4 of Examples 1-5 and Comparative Examples 1-6 were tested according to GB / T13217.4-2020 and GB / T 13217.3-2022, respectively. Viscosity was tested using a rotational viscometer method. A 200 mL sample was taken at 25.0±0.5℃, using rotor No. 1 at 60 rpm. After equilibration for 30 seconds, the viscosity value was read. Each sample was measured three times in parallel, and the arithmetic mean was taken. Fineness was tested using a 0-25 μm scraper fineness meter. A 0.5 mL sample was placed on the high end of the scraper, and a stainless steel scraper was used to scrape the ink at a uniform speed within 2 seconds. The fineness value corresponding to the location where three or more consecutive scratches appeared was read.

[0038] Initial drying time: The initial drying time of the inks corresponding to Examples 1-5 and Comparative Examples 1-6 was tested according to GB / T 13217.5-2023. Each sample was uniformly prepared on a 12μm polyethylene terephthalate film using a 10μm wet film preparation device and immediately placed in a 50℃ forced-air drying oven. Timing began after the sample preparation was completed, and the film was removed every 5 seconds at a rate of 70 g / m². 2 The sample surface was covered with lint-free paper and pressed for 3 seconds under the action of a 200g press block. The initial drying time was recorded when there was no visible color on the surface of the lint-free paper. Each sample was measured in parallel 3 times and the average value was taken.

[0039] Shallow halftone transfer: Following GB / T 36064-2018, the shallow halftone transfer of the inks corresponding to Examples 1-5 and Comparative Examples 1-6 was evaluated using gravure printing. Using the same laboratory gravure proofing machine, the same printing roller, and the same substrate, shallow halftone areas of 5%, 10%, 20%, and 40% were set on the printing roller. After printing, the ink was placed at 23±2℃ for 24 hours. Twenty 100x magnification microscopic fields were randomly selected from the 5% shallow halftone area, and the complete ink-coated area ratio was statistically analyzed using image analysis software. The average value was taken as the complete transfer area ratio of the 5% shallow halftone area.

[0040] Adhesion: Samples of the inks corresponding to Examples 1-5 and Comparative Examples 1-6 were prepared on 12μm polyethylene terephthalate film and 20μm biaxially oriented polypropylene film, respectively. Adhesion was tested using the tape method according to GB / T 13217.7-2023. After placing the printed samples at 23±2℃ for 24 hours, 25 small squares were formed by making 6 cuts each horizontally and vertically using a 1mm spacing crisscross cutter. Transparent pressure-sensitive adhesive tape was then applied and compacted twice with a 2kg rubber roller. After standing for 90 seconds, the samples were rapidly peeled off at a 180° angle. The number of peeled squares was used to grade the samples, with grade 0 indicating no peeling and grade 5 indicating large-area peeling.

[0041] Water resistance to rubbing and friction: The inks corresponding to Examples 1-5 and Comparative Examples 1-6 were subjected to dry and wet rubbing tests according to QB / T 5345-2018. For the dry rubbing test, white cotton cloth was used as the friction medium. The load on the friction head was controlled at 9N, the stroke at 60mm, and the speed at 30 times / min. The number of reciprocating strokes was recorded until the white cotton cloth showed continuous and obvious coloring and the exposed area of ​​the printed material exceeded 10%. For the wet rubbing test, the printed sample was first immersed in deionized water at 23±2℃ for 30min. After removal, the surface water was wiped off, and then rubbed under the same conditions with white cotton cloth with a water absorption rate of 100±5%. The number of reciprocating strokes was recorded when the same endpoint criterion was reached.

[0042] Composite strength: The composite strength of the printed samples of the inks corresponding to Examples 1-5 and Comparative Examples 1-6 was tested according to QB / T 5488-2020. After the above samples were laminated with 60μm cast polypropylene film and cured, they were cut into 15mm wide test strips and placed at 23±2℃ and 50±5% relative humidity for 4h. The test was conducted using an electronic tensile testing machine with a 180° peel method and a tensile speed set to 300mm / min. The average force during the stable peel stage was read, and the result is expressed as N / 15mm.

[0043] Storage stability: The inks corresponding to Examples 1-5 and Comparative Examples 1-6 were sealed and placed in a constant temperature chamber at 50±1℃ for 7 days. After being removed, the temperature was restored to 25℃ and allowed to stand for 24 hours. Subsequently, the viscosity was retested according to GB / T 13217.4-2020. The test results are shown in Table 1.

[0044] Table 1 Performance Test Results

[0045] Data Analysis: As can be seen from the data in Table 1, the water-based gravure printing ink prepared by this invention exhibits a good balance between light-screen transfer, plastic film adhesion, water resistance, post-composite interface stability, and storage stability. The main reason for this is that the three-stage sequential solution polymerization allows the modified acrylic backbone to simultaneously possess relatively hydroxyl-rich segments in the front and relatively carboxyl-rich segments in the rear. This is beneficial for both stable resin dispersion in the aqueous phase and for forming a continuous and relatively dense ink film structure during drying. Furthermore, the two stages of ammonia water and the final stage of 2-amino-2-methyl-1-propanol segmented neutralization can play a role in resin phase reversal, pigment grinding interface replenishment, and curing and storage stages, thereby mitigating the water resistance loss caused by solely relying on high acid values. Simultaneously, the polyethylene wax dispersion further regulates the ink film surface, ensuring that the system balances transferability and abrasion resistance in plastic film printing and subsequent composite applications.

[0046] As can be seen from the data in Table 1 for Example 1 and Comparative Examples 1 and 2, when all monomers are premixed before polymerization, or when the acidic monomers are evenly distributed in each segment while retaining stepwise feeding, the stability of resin particles, shallow network transfer, and composite strength all decrease. This is because, after the relatively carboxyl-rich composition in the third segment is weakened, the dispersion function cannot form a relatively concentrated interfacial stable region on the same modified acrylic acid backbone, making it difficult to simultaneously achieve water dispersion and film anchoring during pigment grinding and film formation stages.

[0047] As can be seen from the data in Table 1 for Example 1 and Comparative Example 3, omitting the step of adding deionized water to reduce viscosity before the first ammonia pre-neutralization resulted in an increase in the average particle size of the resin, and a simultaneous deterioration in fineness, shallow network transfer, and storage stability. The main reason is that high-viscosity systems are more prone to local over-neutralization and phase inhomogeneity when in partial contact with ammonia, leading to premature extension of some chain segments or even the formation of microgels. Even with subsequent water replenishment, it is difficult to restore a uniform dispersion state.

[0048] As can be seen from the data in Table 1 for Example 1 and Comparative Example 4, after the second ammonia water replenishment and neutralization was incorporated into the first stage, the adhesion, wet friction, and composite strength all decreased. This is because the pigment redistributes the resin's adsorption state at the interface after grinding. Without the replenishment and neutralization after grinding, some acidic groups cannot promptly return to a state more suitable for interface wetting and charge stability, resulting in insufficient spreading and anchoring of the ink film on the surfaces of polyethylene terephthalate (PET) and biaxially oriented polypropylene (BOP) films.

[0049] As can be seen from the data in Table 1 for Example 1 and Comparative Example 5, although the initial drying performance did not deteriorate significantly after replacing 2-amino-2-methyl-1-propanol with ammonia in the final stage, the viscosity retention, shallow network transfer, and wet friction performance decreased after storage. The main reason is that ammonia evaporates quickly and has insufficient buffering capacity in the later stages, making the system more prone to local acid-base fluctuations during curing and heat storage, which in turn affects the stability of the resin-pigment interface.

[0050] As can be seen from the data in Table 1 for Example 1 and Comparative Example 6, without the addition of polyethylene wax dispersion, the changes in viscosity, fineness, and adhesion are not significant, but the dry and wet friction properties decrease markedly. This is because the polyethylene wax dispersion mainly acts on the surface structure after film formation, improving surface smoothness and wear resistance without significantly disrupting interfacial adhesion.

[0051] Those skilled in the art should understand that the discussion of any of the above embodiments is merely exemplary and is not intended to imply that the scope of the invention is limited to these examples; within the framework of the invention, the technical features of the above embodiments or different embodiments can also be combined, and there are many other variations of the different aspects of the invention as described above, which are not provided in detail for the sake of brevity.

Claims

1. A water-based gravure printing ink, characterized in that, By weight, it includes the following raw materials: 695-720 parts modified acrylic resin dispersion, 220 parts phthalocyanine blue pigment, 648.8-694.2 parts deionized water, 105-130 parts anhydrous ethanol, 35-45 parts polyethylene wax dispersion, 0.8-1.2 parts ammonia water with a weight fraction of 25%, and 2.5-3.8 parts 2-amino-2-methyl-1-propanol; The modified acrylic resin dispersion is prepared by sequentially solution polymerizing a first monomer mixture, a second monomer mixture, and a third monomer mixture, followed by adding water to reduce viscosity, neutralizing with ammonia, and then dispersing with deionized water.

2. The water-based gravure printing ink according to claim 1, characterized in that, By mass fraction, the first monomer mixture consists of 170-190 parts butyl acrylate, 160-180 parts methyl methacrylate, 125-160 parts isobornyl methacrylate, 66-88 parts 2-hydroxyethyl methacrylate, 4-6 parts methacrylic acid, and 4 parts tert-dodecyl mercaptan; the second monomer mixture consists of 40-50 parts butyl acrylate, 45-55 parts methyl methacrylate, 20-25 parts isobornyl methacrylate, 16-22 parts 2-hydroxyethyl methacrylate, 8-10 parts methacrylic acid, and 1 part tert-dodecyl mercaptan; and the third monomer mixture consists of 80-100 parts butyl acrylate, 115-130 parts methyl methacrylate, 15-20 parts 2-hydroxyethyl methacrylate, 22-40 parts acrylic acid, 18-26 parts methacrylic acid, and 1 part tert-dodecyl mercaptan.

3. The water-based gravure printing ink according to claim 1, characterized in that, By weight, the raw materials of the water-based gravure printing ink also include 6 parts wetting and dispersing agent, 3 parts defoamer, and 1.8-2.2 parts substrate wetting agent.

4. The water-based gravure printing ink according to claim 3, characterized in that, The wetting and dispersing agent is of model number BYK-193; the defoamer is of model number BYK-016; and the substrate wetting agent is of model number BYK-DYNWET 810.

5. The water-based gravure printing ink according to claim 1, characterized in that, The modified acrylic resin dispersion has an acid value of 40-54 mgKOH / g, a hydroxyl value of 43-53 mgKOH / g, and a number-average molecular weight of 13500-17500; the modified acrylic resin dispersion has a solid content of 45.2%-47.4% and a pH of 7.4-8.0 at 25°C.

6. The water-based gravure printing ink according to claim 1, characterized in that, The polyethylene wax dispersion is designated as HORDAMER PE 35.

7. A method for preparing the water-based gravure printing ink according to any one of claims 1-6, characterized in that, Includes the following steps: S1. Preparation of modified acrylic resin dispersion: The first monomer mixture, the second monomer mixture and the third monomer mixture are sequentially subjected to solution polymerization. Then, deionized water is added to reduce viscosity, ammonia is added for the first neutralization, and deionized water is added to disperse the mixture to obtain the modified acrylic resin dispersion. S2. Preparation of grinding slurry: Mix a portion of modified acrylic resin dispersion, phthalocyanine blue pigment, deionized water, anhydrous ethanol, wetting and dispersing agent and a portion of defoamer, then pre-disperse and mill to obtain grinding slurry; S3. Preparation of water-based gravure printing ink: After cooling the grinding slurry, add a diluent made of 25% ammonia and deionized water for a second neutralization and replenishment. Then add the remaining modified acrylic resin dispersion, deionized water, polyethylene wax dispersion, substrate wetting agent, remaining defoamer, anhydrous ethanol and 2-amino-2-methyl-1-propanol, stir, filter and mature to obtain water-based gravure printing ink.

8. The method for preparing water-based gravure printing ink according to claim 7, characterized in that, In step S1, the sequential solution polymerization uses azobisisobutyronitrile as the initiator and 1-methoxy-2-propanol and anhydrous ethanol as solvents.

9. The method for preparing water-based gravure printing ink according to claim 7, characterized in that, In step S2, the amount of modified acrylic resin dispersion added is 55wt%-65wt% of the total amount added; the amount of defoamer added is 60wt%-70wt% of the total amount added.

10. The method for preparing water-based gravure printing ink according to claim 7, characterized in that, In step S2, the grinding process uses zirconia beads with a diameter of 1 mm and is carried out at 1800 rpm for 75-85 minutes, while controlling the material temperature to be no higher than 40℃.

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