Anti-fading water-based environment-friendly ink and preparation method thereof

Abstract

The invention relates to the field of environment-friendly ink materials, in particular to anti-fading water-based environment-friendly ink and a preparation method thereof. The anti-fading water-based environment-friendly ink comprises the following substances in parts by weight: 40-60 parts of resin emulsion; 10 to 20 parts of pigment; 2-8 parts of a cross-linking agent; 0.5 to 2.0 parts of a wetting agent; 20 to 30 parts of deionized water; the resin emulsion comprises an acrylic acid-polyurethane composite resin emulsion, the acrylic acid-polyurethane composite resin emulsion is formed by crosslinking an acrylate monomer and a polyurethane prepolymer, and the mass ratio of the acrylate monomer to the polyurethane prepolymer is (3: 1)-(5: 1). The balance and functionality of the ink system are ensured by limiting the ratio range of the resin emulsion, the pigment, the cross-linking agent, the wetting agent and the deionized water. Meanwhile, the acrylic acid-polyurethane composite resin emulsion is selected as a film forming substrate, and the weather resistance of acrylic acid and the flexibility of polyurethane are combined, so that the problem that the mechanical property and the chemical resistance of the traditional water-based ink are difficult to consider at the same time is solved.

Description

Technical Field

[0001] The present application relates to the field of environmentally friendly ink materials, and in particular to an anti-fading water-based environmentally friendly ink and a preparation method thereof. Background Art

[0002] Traditional water-based inks use water as the dispersion medium, with acrylic resins, polyurethane resins, or physical blends of the two as the film-forming matrix, supplemented with pigments, additives, and other components. Early water-based inks were primarily used for printing low-end paper products due to the resin's insufficient water resistance and adhesion. With environmental regulations restricting solvent-based inks, water-based inks are gradually developing towards higher performance.

[0003] In recent years, environmentally friendly water-based ink technology has focused on resin composite modification and pigment functionalization. Within the resin system, acrylic-polyurethane hybrid technology achieves synergistic benefits through chemical bonding rather than physical blending. For example, a core-shell structure design, with polyurethane as the core for flexibility and acrylic ester as the shell for enhanced weather resistance, increases the ink's tensile strength to over 12 MPa while significantly improving its water resistance. Furthermore, the introduction of self-crosslinking monomers and the use of metal ion crosslinkers further enhance the ink's chemical and abrasion resistance.

[0004] In response to the above-mentioned existing technologies, the inventors found that the existing environmentally friendly water-based ink resins have insufficient interfacial compatibility with pigments, the hydroxyl groups on the surface of inorganic pigments have weak interaction with the polar groups of the resin, and microcracks are easily generated at the interface after printing, causing the ink layer to peel off under mechanical stress or solvent erosion. The pigment loading technology is limited by the clogging of the carrier pores and poor dispersion stability. The actual loading rate of carriers such as nano-mesoporous silica is insufficient, resulting in serious discoloration of the final prepared ink material and poor durability. Summary of the Invention

[0005] In order to improve the above technical problems, the present application provides an anti-fading water-based environmentally friendly ink and a preparation method thereof.

[0006] In the first aspect, the present application provides an anti-fading water-based environmentally friendly ink, which adopts the following technical solutions: A water-based environmentally friendly anti-fading ink comprises the following substances in parts by weight: 40-60 parts of a resin emulsion; 10-20 parts of a pigment; 2-8 parts of a cross-linking agent; 0.5-2.0 parts of a wetting agent; and 20-30 parts of deionized water. The resin emulsion comprises an acrylic acid-polyurethane composite resin emulsion, which is formed by cross-linking an acrylic acid ester monomer and a polyurethane prepolymer. The mass ratio of the acrylic acid ester monomer to the polyurethane prepolymer is (3:1) to (5:1).

[0007] Through the above technical solution, the present application ensures the balance and functionality of the ink system by limiting the ratio range of resin emulsion, pigment, cross-linking agent, wetting agent and deionized water. At the same time, the present application selects acrylic-polyurethane composite resin emulsion as the film-forming matrix, combining the weather resistance of acrylic acid with the flexibility of polyurethane, and solves the problem that traditional water-based inks are difficult to balance mechanical properties and chemical resistance. The design of the mass ratio range not only ensures the synergistic effect of the two, but also avoids the performance imbalance caused by excessive use of a single resin. The synergistic effect of pigment and resin enhances the adhesion of the ink to the substrate, and the introduction of the cross-linking agent further increases the cross-linking density and enhances solvent resistance. The addition of the wetting agent optimizes the leveling and wettability of the ink, and deionized water as a solvent ensures the environmental protection characteristics of low VOCs.

[0008] Furthermore, the polyurethane prepolymer is prepared by reacting isophorone diisocyanate and polyether diol at a ratio of NCO:OH=1.02-1.10:1.

[0009] Through the above technical solution, this application defines the synthetic raw materials and reaction ratios for the polyurethane prepolymer. Isophorone diisocyanate offers high reactivity and weather resistance, while polyether diol imparts excellent flexibility to the prepolymer. By controlling the molar ratio of NCO to hydroxyl groups, the density of urethane groups in the prepolymer molecular chain is maintained at a moderate level, avoiding both resin embrittlement caused by excessive crosslinking and decreased solvent resistance caused by insufficient crosslinking. This ratio optimizes the compatibility between the polyurethane prepolymer and acrylic monomer, laying the foundation for the stability of the subsequent composite emulsion.

[0010] Furthermore, the pigment includes inorganic pigment particles and a polydopamine organic coating layer coated on the surface of the inorganic pigment particles.

[0011] Through the above technical solution, this application addresses the weak interfacial bonding between traditional inorganic pigments and resins by introducing polydopamine-coated inorganic pigment particles. The adhesive properties of polydopamine and the abundant polar groups (such as amino and hydroxyl groups) on its surface enhance the chemical bonding between the pigment and the resin, reducing interfacial defects. Furthermore, the PDA coating shields the pigment from direct contact with external solvents, improving chemical resistance. The organic-inorganic composite structure also improves pigment dispersion, preventing agglomeration that can cause ink sedimentation or uneven printing.

[0012] Furthermore, the pigment further includes an inorganic coating carrier, and the inorganic coating carrier includes nano-mesoporous silica particles.

[0013] Through the above technical solution, the present application introduces nano-mesoporous silica as a carrier in the pigment system, further optimizing the pigment loading efficiency. The high specific surface area of the mesoporous structure provides a large number of adsorption sites, which fix the inorganic pigment particles by physical adsorption or chemical bonding, significantly improving the pigment loading rate. The rigid skeleton of the silica carrier can also relieve mechanical stress during the printing process and reduce the peeling of the ink layer due to external forces. In addition, the carrier surface can be modified by a silane coupling agent to enhance compatibility with the resin and form a stable three-dimensional network structure.

[0014] Furthermore, the nano-mesoporous silica particles have a particle size of 2-10 μm and a specific surface area of 1000-1500 m 2 / g.

[0015] Through the above technical solution, this application defines the particle size and specific surface area range of nano-mesoporous silica. The rational design of the mesopore size ensures the effective embedding and stable loading of pigment particles, avoiding blockage due to too small pore size or loose loading due to too large pore size. The high specific surface area not only increases the adsorption capacity of the carrier, but also enhances the interfacial bonding force through the hydrogen bonding between the surface hydroxyl groups and the resin. The optimization of the particle size balances the dispersibility and system viscosity, avoiding the agglomeration of nanoparticles due to being too small or the decrease in ink fluidity due to being too large.

[0016] Furthermore, the inorganic pigment particles include at least one of rutile titanium dioxide, red iron oxide or cobalt blue.

[0017] Through the above technical solution, this application clarifies the selection range of inorganic pigments. The high hiding power and weather resistance of rutile titanium dioxide, the color stability of iron oxide red, and the high-temperature resistance of cobalt blue all provide excellent color rendering properties for environmentally friendly inks. After being coated with polydopamine, these pigments retain the high stability of inorganic materials while overcoming compatibility barriers with resins through organic layer modification.

[0018] Furthermore, the pigment is prepared using the following technical solution: Taking inorganic pigment particles and mixing them with a silane coupling agent solution, centrifuging and washing and drying, and collecting activated pigments; The activated pigment and nano-mesoporous silica particles were stirred and mixed, and then placed in a buffer solution. Dopamine hydrochloride and an oxidant were added. After reacting for 24 hours at room temperature and under a nitrogen atmosphere, the organic-inorganic hybrid pigment was prepared by washing and drying.

[0019] Through the above technical solution, the present application enhances the bonding strength between the inorganic pigment and the mesoporous carrier by surface activation treatment of the inorganic pigment with a silane coupling agent, thus solving the problem of easy pigment shedding in traditional loading technology. Dopamine undergoes oxidative self-polymerization under weak alkaline conditions to form a uniform and dense coating layer, avoiding the formation of free PDA particles. Nitrogen protection inhibits side reactions and ensures the integrity of the coating structure. This process achieves efficient pigment-carrier hybridization through step-by-step activation and compounding, significantly improving the storage stability and printing performance of the ink.

[0020] In a second aspect, the present application provides a method for preparing an anti-fading water-based environmentally friendly ink, which adopts the following technical solutions: A method for preparing an anti-fading water-based environmentally friendly ink comprises the following steps: The resin emulsion and pigment are stirred and mixed and placed in a high-speed shearing machine for shearing treatment, a cross-linking agent, a wetting agent and deionized water are added, ultrasonic dispersion is performed, the pH is adjusted and vacuum degassing is performed, and a thickener is added to adjust the viscosity to prepare an anti-fading water-based environmentally friendly ink.

[0021] Through the above technical solution, the present application achieves uniform dispersion of the resin emulsion and the pigment through high-speed shearing, avoiding phase separation or local agglomeration caused by traditional stirring. Ultrasonic treatment further refines the dispersed phase size to ensure the monodispersity of the pigment particles in the system. pH adjustment optimizes the stability of the resin emulsion and prevents demulsification or viscosity mutation caused by pH fluctuations. Vacuum degassing eliminates the influence of microbubbles on film quality, and the precise addition of thickeners balances the rheological properties of the ink, making it adaptable to the needs of different printing processes.

[0022] Furthermore, the viscosity of the anti-fading water-based environmentally friendly ink is 20-200 mPa·s.

[0023] Through the above technical solution, this application ensures that the ink has good fluidity and transferability during the printing process by limiting its viscosity range. The low viscosity range ensures rapid leveling of the ink and clear dots; the high viscosity range is suitable for flexographic printing, avoiding ink flying or print-through due to low viscosity. Precise control of viscosity also affects the storage stability of the ink, preventing sedimentation caused by high viscosity or delamination caused by low viscosity. The design of this range balances printability and performance requirements, broadening the application scenarios of the ink.

[0024] In summary, this application has the following beneficial effects: First, this application ensures the balance and functionality of the ink system by limiting the ratio range of resin emulsion, pigment, cross-linking agent, wetting agent and deionized water. At the same time, this application selects acrylic-polyurethane composite resin emulsion as the film-forming matrix, combining the weather resistance of acrylic acid with the flexibility of polyurethane, to solve the problem that traditional water-based inks are difficult to balance mechanical properties and chemical resistance. The design of the mass ratio range not only ensures the synergistic effect of the two, but also avoids the performance imbalance caused by excessive use of a single resin. The synergistic effect of pigment and resin enhances the adhesion of the ink to the substrate, and the introduction of the cross-linking agent further increases the cross-linking density and enhances solvent resistance. The addition of the wetting agent optimizes the leveling and wettability of the ink, and deionized water as a solvent ensures the environmentally friendly characteristics of low VOCs.

[0025] Second, this application addresses the weak interfacial bonding between traditional inorganic pigments and resins by introducing polydopamine-coated inorganic pigment particles. The adhesive properties of polydopamine and the abundant surface polar groups (such as amino and hydroxyl groups) enhance the chemical bond between the pigment and the resin, reducing interfacial defects. Furthermore, the PDA coating shields the pigment from direct contact with external solvents, improving chemical resistance. The organic-inorganic composite structure also improves pigment dispersion, preventing agglomeration that can lead to ink sedimentation or uneven printing.

[0026] Third, the present application introduces nano-mesoporous silica as a carrier in the pigment system, further optimizing the pigment loading efficiency. The high specific surface area of the mesoporous structure provides a large number of adsorption sites, which fix the inorganic pigment particles by physical adsorption or chemical bonding, significantly improving the pigment loading rate. The rigid skeleton of the silica carrier can also relieve mechanical stress during the printing process and reduce the peeling of the ink layer due to external forces. In addition, the carrier surface can be modified by a silane coupling agent to enhance compatibility with the resin and form a stable three-dimensional network structure.

[0027] Fourth, the present application achieves uniform dispersion of the resin emulsion and pigment through high-speed shearing, avoiding phase separation or local agglomeration caused by traditional stirring. Ultrasonic treatment further refines the dispersed phase size to ensure the monodispersity of the pigment particles in the system. pH adjustment optimizes the stability of the resin emulsion, preventing demulsification or viscosity mutations caused by pH fluctuations. Vacuum degassing eliminates the impact of microbubbles on film quality, and the precise addition of thickeners balances the rheological properties of the ink, making it adaptable to the needs of different printing processes. DETAILED DESCRIPTION

[0028] The present application is further described in detail below with reference to the embodiments.

[0029] Preparation Example Preparation Example 1 Acrylic acid-polyurethane composite resin emulsion 1 According to the ratio of NCO:OH=1.02:1, isophorone diisocyanate and polyether diol were reacted at 75°C in a nitrogen atmosphere for 2 hours, dimethylol propionic acid was added to extend the chain, the temperature was raised to 80°C, and the reaction was continued until the NCO content reached the standard. The temperature was then lowered to 40°C, and triethylamine was added dropwise to neutralize the mixture to pH=7.5. The mixture was emulsified at a high shear speed of 12000 rpm for 15 minutes, and then diluted with water to a solid content of 35%. The prepolymer emulsion was collected. Glycidyl methacrylate, acrylic acid, butyl acrylate and methyl methacrylate were stirred and mixed in a mass ratio of 5:3:35:40 to obtain a pre-emulsified acrylate monomer. The prepolymer emulsion was heated to 80°C in a mass ratio of acrylate monomer to polyurethane prepolymer of 3:1, and the pre-emulsified acrylate monomer was added dropwise under a nitrogen atmosphere. After the addition was completed, the mixture was kept warm for 1 hour, and acetoacetoxyethyl methacrylate was added for post-crosslinking. The mixture was reacted at 65°C for 2 hours and cooled to obtain an acrylic-polyurethane composite resin emulsion 1.

[0030] Preparation Example 2 Acrylic-polyurethane composite resin emulsion 2 According to the ratio of NCO:OH=1.06:1, isophorone diisocyanate and polyether diol were reacted at 75°C in a nitrogen atmosphere for 2 hours, dimethylol propionic acid was added to extend the chain, the temperature was raised to 80°C, and the reaction was continued until the NCO content reached the standard. The temperature was then lowered to 40°C, and triethylamine was added dropwise to neutralize the mixture to pH=7.5. The mixture was emulsified at a high shear speed of 12000 rpm for 15 minutes, and then diluted with water to a solid content of 35%. The prepolymer emulsion was collected. Glycidyl methacrylate, acrylic acid, butyl acrylate and methyl methacrylate were stirred and mixed in a mass ratio of 5:3:35:40 to obtain a pre-emulsified acrylate monomer. The prepolymer emulsion was heated to 80°C in a mass ratio of acrylate monomer to polyurethane prepolymer of 4:1. The pre-emulsified acrylate monomer was then added dropwise under a nitrogen atmosphere. After the addition was complete, the mixture was kept warm for 1 hour. Acetylacetoxyethyl methacrylate was added for post-crosslinking. The mixture was reacted at 65°C for 2 hours and cooled to obtain an acrylic-polyurethane composite resin emulsion 2.

[0031] Preparation Example 3 Acrylic-polyurethane composite resin emulsion 3 According to the ratio of NCO:OH=1.10:1, isophorone diisocyanate and polyether diol were reacted at 75°C in a nitrogen atmosphere for 2 hours, dimethylol propionic acid was added to extend the chain, the temperature was raised to 80°C, and the reaction was continued until the NCO content reached the standard. The temperature was then lowered to 40°C, and triethylamine was added dropwise to neutralize the mixture to pH=7.5. The mixture was emulsified at a high shear speed of 12000 rpm for 15 minutes, and then diluted with water to a solid content of 35%. The prepolymer emulsion was collected. Glycidyl methacrylate, acrylic acid, butyl acrylate, and methyl methacrylate were stirred and mixed in a mass ratio of 5:3:35:40 to obtain a pre-emulsified acrylate monomer. The prepolymer emulsion was heated to 80°C in a mass ratio of acrylate monomer to polyurethane prepolymer of 5:1. The pre-emulsified acrylate monomer was then added dropwise under a nitrogen atmosphere. After the addition was complete, the mixture was kept warm for 1 hour. Acetylacetoxyethyl methacrylate was added for post-crosslinking. The mixture was reacted at 65°C for 2 hours and cooled to obtain acrylic-polyurethane composite resin emulsion 3.

[0032] Preparation Example 4 200 g of rutile titanium dioxide was placed in 1000 g of a 1.5% by mass silane coupling agent KH570 ethanol solution and stirred at 75°C for 2 h. After centrifugal washing and drying, it was dispersed in a Tris-HCl buffer solution with a pH of 8.5. 30% of dopamine hydrochloride by mass of the titanium dioxide and 0.01% of ammonium persulfate by mass of the titanium dioxide were added as oxidants. After reacting under nitrogen protection at room temperature for 24 h, the mixture was centrifuged and washed until neutral, and vacuum dried at 60°C to prepare pigment 1.

[0033] Preparation Example 5 Take 200g of rutile titanium dioxide and place it in 1000g of 1.5% silane coupling agent KH570 ethanol solution and stir it at 75℃ for 2h. After centrifugal washing and drying, mix it with 200g of 5μm particle size and 1200m3 specific surface area. 2 / g of mesoporous SiO2 was stirred, mixed and dispersed in Tris-HCl buffer at pH=8.5, and 30% of dopamine hydrochloride by weight of titanium dioxide and 0.01% of ammonium persulfate by weight of titanium dioxide were added as oxidants. After the reaction was carried out under nitrogen protection at room temperature for 24 hours, the pigment was washed by centrifugation until neutral, and dried in vacuum at 60°C to prepare pigment 2.

[0034] Example 1 The invention discloses an anti-fading water-based environmentally friendly ink comprising: 40 kg of acrylic acid-polyurethane composite resin emulsion 1, 10 kg of pigment 1, 2 kg of cross-linking agent methacrylate acetoacetate glycol diester, 0.5 kg of wetting agent BYK-349 and 20 kg of deionized water.

[0035] A method for preparing an anti-fading water-based environmentally friendly ink comprises the following steps: The resin emulsion and pigment were stirred and mixed and placed in a high-speed shearing machine at 10,000 rpm for 20 minutes. A crosslinking agent, a wetting agent and deionized water were added, and ultrasonic dispersion was performed at 40 kHz for 30 minutes. The pH was adjusted to 8.8 with AMP-95, and the mixture was placed in a vacuum degassing treatment at -0.08 MPa and 40°C for 1 hour. The thickener ASE-60 was added to adjust the viscosity to 50 mPa·s to prepare a color-fading-resistant water-based environmentally friendly ink.

[0036] Example 2 The invention discloses an anti-fading water-based environmentally friendly ink comprising: 50 kg of acrylic acid-polyurethane composite resin emulsion 1, 15 kg of pigment 1, 5 kg of cross-linking agent methacrylate acetoacetate glycol diester, 1.2 kg of wetting agent BYK-349 and 25 kg of deionized water.

[0037] A method for preparing an anti-fading water-based environmentally friendly ink comprises the following steps: The resin emulsion and pigment were stirred and mixed and placed in a high-speed shearing machine at 10,000 rpm for 20 minutes. A crosslinking agent, a wetting agent and deionized water were added, and ultrasonic dispersion was performed at 40 kHz for 30 minutes. The pH was adjusted to 8.8 with AMP-95, and the mixture was placed in a vacuum degassing treatment at -0.08 MPa and 40°C for 1 hour. The thickener ASE-60 was added to adjust the viscosity to 100 mPa·s to prepare a color-fading-resistant water-based environmentally friendly ink.

[0038] Example 3 The invention discloses an anti-fading water-based environmentally friendly ink comprising: 60 kg of acrylic acid-polyurethane composite resin emulsion 1, 20 kg of pigment 1, 8 kg of cross-linking agent methacrylate acetoacetate glycol diester, 2.0 kg of wetting agent BYK-349 and 30 kg of deionized water.

[0039] A method for preparing an anti-fading water-based environmentally friendly ink comprises the following steps: The resin emulsion and pigment were stirred and mixed and placed in a high-speed shearing machine at 10,000 rpm for 20 minutes. A crosslinking agent, a wetting agent and deionized water were added, and ultrasonic dispersion was performed at 40 kHz for 30 minutes. The pH was adjusted to 8.8 with AMP-95, and the mixture was placed in a vacuum degassing treatment at -0.08 MPa and 40°C for 1 hour. The thickener ASE-60 was added to adjust the viscosity to 180 mPa·s to prepare a color-fading-resistant water-based environmentally friendly ink.

[0040] Example 4 The invention discloses an anti-fading water-based environmentally friendly ink comprising: 50 kg of acrylic acid-polyurethane composite resin emulsion 2, 15 kg of pigment 1, 5 kg of cross-linking agent methacrylate acetoacetate glycol diester, 1.2 kg of wetting agent BYK-349 and 25 kg of deionized water.

[0041] A method for preparing an anti-fading water-based environmentally friendly ink comprises the following steps: The resin emulsion and pigment were stirred and mixed and placed in a high-speed shearing machine at 10,000 rpm for 20 minutes. A crosslinking agent, a wetting agent and deionized water were added, and ultrasonic dispersion was performed at 40 kHz for 30 minutes. The pH was adjusted to 8.8 with AMP-95, and the mixture was placed in a vacuum degassing treatment at -0.08 MPa and 40°C for 1 hour. The thickener ASE-60 was added to adjust the viscosity to 100 mPa·s to prepare a color-fading-resistant water-based environmentally friendly ink.

[0042] Example 5 The invention discloses an anti-fading water-based environmentally friendly ink comprising: 50 kg of acrylic acid-polyurethane composite resin emulsion 3, 15 kg of pigment 1, 5 kg of cross-linking agent methacrylate acetoacetate glycol diester, 1.2 kg of wetting agent BYK-349 and 25 kg of deionized water.

[0043] A method for preparing an anti-fading water-based environmentally friendly ink comprises the following steps: The resin emulsion and pigment were stirred and mixed and placed in a high-speed shearing machine at 10,000 rpm for 20 minutes. A crosslinking agent, a wetting agent and deionized water were added, and ultrasonic dispersion was performed at 40 kHz for 30 minutes. The pH was adjusted to 8.8 with AMP-95, and the mixture was placed in a vacuum degassing treatment at -0.08 MPa and 40°C for 1 hour. The thickener ASE-60 was added to adjust the viscosity to 100 mPa·s to prepare a color-fading-resistant water-based environmentally friendly ink.

[0044] Example 6 The invention discloses an anti-fading water-based environmentally friendly ink comprising: 50 kg of acrylic acid-polyurethane composite resin emulsion 2, 15 kg of pigment 2, 5 kg of cross-linking agent methacrylate acetoacetate glycol diester, 1.2 kg of wetting agent BYK-349 and 25 kg of deionized water.

[0045] A method for preparing an anti-fading water-based environmentally friendly ink comprises the following steps: The resin emulsion and pigment were stirred and mixed and placed in a high-speed shearing machine at 10,000 rpm for 20 minutes. A crosslinking agent, a wetting agent and deionized water were added, and ultrasonic dispersion was performed at 40 kHz for 30 minutes. The pH was adjusted to 8.8 with AMP-95, and the mixture was placed in a vacuum degassing treatment at -0.08 MPa and 40°C for 1 hour. The thickener ASE-60 was added to adjust the viscosity to 100 mPa·s to prepare a color-fading-resistant water-based environmentally friendly ink.

[0046] Comparative Example 1 Unmodified titanium dioxide was selected as the pigment, and the rest of the preparation scheme and process were the same as those in Example 1.

[0047] Comparative Example 2 Ordinary acrylic resin emulsion was selected to replace the acrylic acid-polyurethane composite resin emulsion in Example 1, and the rest of the preparation scheme and process were the same as those in Example 1.

[0048] Performance testing The inks prepared in Examples 1-6 and Comparative Examples 1-2 were subjected to performance tests, wherein the test standards are as follows: Adhesion: GB / T 9286-2021 (cross-hatch method, 0-5 levels, 0 is the best); Abrasion resistance: ASTM D4060-2019 (Taber abrasion, the lower the mass loss, the better); VOCs content: GB 38507-2020 (gas chromatography, unit: g / L).

[0049] The test results are shown in Table 1 below: Table 1 Performance test table

[0050] It can be found from the data in the examples, combined with the comparison between Examples 1-3 and Comparative Example 1, that the technical solution of the present application solves the problem of the difficulty in balancing the mechanical properties and chemical resistance of traditional water-based inks by selecting an acrylic-polyurethane composite resin emulsion as a film-forming matrix and combining the weather resistance of acrylic acid with the flexibility of polyurethane.

[0051] Combined with Examples 1-5 and Comparative Examples 1 and 6, it is further illustrated that the technical solution of the present application solves the problem of weak interfacial bonding between traditional inorganic pigments and resins by introducing polydopamine-coated inorganic pigment particles. At the same time, by introducing nano-mesoporous silica as a carrier in the pigment system, the pigment loading efficiency is further optimized. The high specific surface area of the mesoporous structure provides a large number of adsorption sites, which fix the inorganic pigment particles by physical adsorption or chemical bonding, significantly improving the pigment loading rate. The rigid skeleton of the silica carrier can also relieve mechanical stress during the printing process and reduce the peeling of the ink layer due to external forces.

[0052] This specific embodiment is merely an explanation of the present application and is not a limitation of the present application. After reading this specification, those skilled in the art may make non-creative modifications to the present embodiment as needed, but as long as they are within the scope of the claims of the present application, they are protected by the patent law.

Claims

1. A water-based environmentally friendly anti-fading ink, characterized in that: The composition includes the following materials in parts by weight: 40-60 parts of resin emulsion; 10-20 parts of pigment; 2-8 parts of cross-linking agent; Wetting agent 0.5-2.0 parts; 20-30 parts of deionized water; The resin emulsion includes an acrylic acid-polyurethane composite resin emulsion, which is formed by cross-linking an acrylic acid ester monomer and a polyurethane prepolymer. The mass ratio of the acrylic acid ester monomer to the polyurethane prepolymer is (3:1)-(5:1).

2. The anti-fading water-based environmentally friendly ink according to claim 1, characterized in that: The polyurethane prepolymer is prepared by reacting isophorone diisocyanate and polyether diol according to the ratio of NCO:OH=1.02-1.10:

1.

3. The anti-fading water-based environmentally friendly ink according to claim 1, characterized in that: The pigment comprises inorganic pigment particles and a polydopamine organic coating layer coated on the surface of the inorganic pigment particles.

4. The anti-fading water-based environmentally friendly ink according to claim 3, characterized in that: The pigment further comprises an inorganic coating carrier, and the inorganic coating carrier comprises nano-mesoporous silica particles.

5. The anti-fading water-based environmentally friendly ink according to claim 4, characterized in that: The nano-mesoporous silica particles have a particle size of 2-10 μm and a specific surface area of 1000-1500 m 2 / g.

6. The anti-fading water-based environmentally friendly ink according to claim 3, characterized in that: The inorganic pigment particles include at least one of rutile titanium dioxide, red iron oxide or cobalt blue.

7. The anti-fading water-based environmentally friendly ink according to claim 5, characterized in that: The pigment is prepared by the following technical solution: Taking inorganic pigment particles and mixing them with a silane coupling agent solution, centrifuging and washing and drying, and collecting activated pigments; The activated pigment and nano-mesoporous silica particles were stirred and mixed, and then placed in a buffer solution. Dopamine hydrochloride and an oxidant were added. After reacting for 24 hours at room temperature and under a nitrogen atmosphere, the organic-inorganic hybrid pigment was prepared by washing and drying.

8. The method for preparing a water-based environmentally friendly anti-fading ink according to any one of claims 1 to 7, characterized in that: The method comprises the following preparation steps: The resin emulsion and pigment are stirred and mixed and placed in a high-speed shearing machine for shearing treatment, a cross-linking agent, a wetting agent and deionized water are added, ultrasonic dispersion is performed, the pH is adjusted and vacuum degassing is performed, and a thickener is added to adjust the viscosity to prepare an anti-fading water-based environmentally friendly ink.

9. The method for preparing a water-based environmentally friendly anti-fading ink according to claim 8, characterized in that: The viscosity of the anti-fading water-based environmentally friendly ink is 20-200 mPa·s.

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