UV-curable water-based paint and preparation method thereof

Abstract

The invention relates to the technical field of coatings, and discloses a UV-curable water-based coating and a preparation method thereof. The UV-cured water-based paint is prepared by taking water-based polyurethane acrylate emulsion and water-based epoxy modified acrylic resin as main raw materials, adding functional aids such as a modified antibacterial agent, an inorganic filler, a photoinitiator and a silane coupling agent, and mixing. Wherein the modified antibacterial agent utilizes the synergistic effect among a benzoxazine structure, a quaternary ammonium salt structure, a thiazole structure and a carbon-carbon double bond to endow the coating with excellent antibacterial performance, so that the application field of the coating is widened, and the coating has certain application prospects in the aspects of wooden furniture, plastic products, printing and packaging and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to a UV-curable water-based coating and a preparation method thereof. Background Art

[0002] With increasingly stringent environmental regulations and rising consumer health awareness, water-based coatings, owing to their low VOC (volatile organic compound) profile, have become a valuable alternative to traditional solvent-based coatings. UV-curable water-based coatings, in particular, combine the environmental advantages of waterborne systems with the high efficiency of UV curing technology (curing in seconds and low energy consumption), gaining widespread application in wood, plastics, metals, packaging, and printing. However, in high-humidity, high-contact environments (such as medical equipment, furniture surfaces, and food packaging), coating surfaces are susceptible to the growth of microorganisms such as bacteria and mold, which not only affects aesthetics but also poses potential health and safety concerns. Therefore, the development of UV-curable water-based coatings with long-lasting antimicrobial properties has become a key research direction in the industry.

[0003] Traditional water-based coatings improve their antimicrobial properties by adding organic, inorganic, or natural antimicrobial agents. However, these agents all have drawbacks. For example, quaternary ammonium salts, while having a broad antimicrobial spectrum, are prone to migration and precipitation, resulting in a short antimicrobial lifespan. Inorganic antimicrobial agents (nanosilver, zinc ions), while heat-resistant, are prone to agglomeration, affecting dispersion. High addition levels can hinder UV curing reactions and reduce the mechanical properties of the coating. Natural antimicrobial agents (chitosan), while highly safe, have poor weather resistance and are easily degraded by UV. Therefore, to overcome these limitations, researchers have enhanced the comprehensive performance of antimicrobial agents through chemical structure modification, enabling them to exhibit long-lasting antimicrobial properties and resist migration in UV-curable water-based coatings. Summary of the Invention

[0004] In order to solve the above technical problems, the present invention provides a UV curing water-based coating and a preparation method thereof.

[0005] The purpose of the present invention can be achieved through the following technical solutions: A UV curable water-based coating comprises the following raw materials in parts by weight: 40-50 parts of a water-based polyurethane acrylate emulsion, 15-25 parts of a water-based epoxy-modified acrylic resin, 7-12 parts of a modified antibacterial agent, 8-12 parts of an inorganic filler, 2-4 parts of a silane coupling agent, 2-5 parts of a photoinitiator, 0.3-0.6 parts of a leveling agent, 0.4-0.8 parts of a defoaming agent, 0.2-0.5 parts of a dispersant, 3-7 parts of isopropyl alcohol, and 10-15 parts of water; Furthermore, the inorganic filler is one of nano calcium carbonate or white carbon black; Furthermore, the silane coupling agent is one of KH560 or KH570; Further, the photoinitiator is one of photoinitiator 184 or photoinitiator TPO-L; Furthermore, the leveling agent is leveling agent BYK-3455; Furthermore, the defoamer is defoamer BYK-1794; Furthermore, the dispersant is dispersant BYK-2013; The modified antibacterial agent is prepared by the following steps: Step A1, p-chlorophenol and water are mixed and stirred to form a mixed solution, 1,3-propylenediamine, anhydrous potassium carbonate and water are mixed and stirred to form a mixed solution, and then slowly added dropwise to the mixed solution. The mixture is reacted in an ice-water bath for 1-2 hours, the temperature is raised to room temperature and stirred for 5-7 hours, and the mixture is filtered, washed, dried and recrystallized to obtain a phenol derivative; Furthermore, in step A1, the molar ratio of p-chlorophenol, 1,3-propylenediamine and anhydrous potassium carbonate is 0.2-0.203:0.1:0.05-0.08; Step A2: adding a phenol derivative and paraformaldehyde to a mixture of toluene and ethanol, heating the mixture to 80° C. under stirring in an oil bath and reflux for 30-50 minutes, then slowly adding a 2-amino-4-methylthiazole toluene solution, reflux for 24 hours, rotary evaporation, and recrystallization to obtain a benzoxazine derivative; Furthermore, in step A2, the ratio of the amount of phenol derivative, paraformaldehyde, toluene, ethanol and 2-amino-4-methylthiazole toluene solution is 0.05-0.1 mol: 0.21-0.42 mol: 80 mL: 20 mL: 50 mL; Furthermore, the ratio of 2-amino-4-methylthiazole to toluene in the 2-amino-4-methylthiazole toluene solution in step A2 is 0.1-0.2 mol:50 mL; Step A3: A benzoxazine derivative and triethylamine are stirred uniformly in tetrahydrofuran to form a solution 1. 4-pentenoyl chloride is stirred uniformly in tetrahydrofuran, and then the solution 1 is slowly added. The mixture is stirred in an oil bath at 40°C for 4-6 hours, filtered, rotary evaporated, washed, filtered a second time, and dried to obtain an alkenyl-benzoxazine derivative. Furthermore, in step A3, the ratio of 4-pentenoyl chloride, tetrahydrofuran, and solution 1 is 0.01-0.02 mol:50 mL:50 mL; Furthermore, the amount ratio of the benzoxazine derivative, triethylamine and tetrahydrofuran in the solution 1 of step A3 is 0.01 mol:0.011 mol:50 mL; Step A4: Under nitrogen, stir the alkenyl-benzoxazine derivative in a mixture of ethanol and water, slowly add chloroalkane dropwise, and heat to 50-70° C., stir and react for 12-18 hours, filter, wash, and dry to obtain a modified antibacterial agent. Furthermore, in step A4, the ratio of the amount of alkenyl-benzoxazine derivative, ethanol, water and chloroalkane is 0.01 mol:70 mL:30 mL:0.01-0.02 mol; Furthermore, the chlorinated alkane in step A4 is one of 1-chlorododecane, n-octyl chloride, 1-chlorodecane or 1-chlorohexane.

[0006] A method for preparing a UV-curable water-based coating comprises the following steps: The raw materials are weighed in parts by weight, and the waterborne polyurethane acrylate emulsion, waterborne epoxy modified acrylic resin, modified antibacterial agent, inorganic filler, photoinitiator, silane coupling agent, leveling agent, defoaming agent, dispersant, isopropyl alcohol and water are mixed and stirred uniformly to obtain a UV curing waterborne coating.

[0007] Beneficial effects of the present invention: The UV-curable water-based coating of the present invention is made from a water-based polyurethane acrylate emulsion and a water-based epoxy-modified acrylic resin as primary raw materials, along with functional additives such as a modified antimicrobial agent, an inorganic filler, a photoinitiator, and a silane coupling agent. The addition of the modified antimicrobial agent imparts excellent antimicrobial properties to the coating, broadening its application areas and making it promising for applications in wooden furniture, plastic products, printing and packaging, and other areas.

[0008] The modified antimicrobial agent prepared by the present invention utilizes the synergistic effects of a benzoxazine structure, a quaternary ammonium salt structure, a thiazole structure, and a carbon-carbon double bond to impart rapid bactericidal and long-lasting antimicrobial properties to the coating. The benzoxazine structure, upon contact with bacteria, can disrupt the integrity of bacterial cell membranes, leading to bacterial death. The thiazole ring, an aromatic ring containing elements such as nitrogen, carbon, and sulfur, possesses strong electrophilic and nucleophilic properties, interacting with key components in pathogenic cells to exhibit a powerful bactericidal effect. The quaternary ammonium salt structure, a common antimicrobial component, can synergize with the thiazole ring and benzoxazine structure to further enhance the antimicrobial properties of the substrate. In addition, the presence of the carbon-carbon double bond structure enables the modified antimicrobial agent to participate in the curing of the matrix. Under the action of the initiator and UV light, it undergoes a free radical polymerization reaction with a large number of acrylate double bonds in the coating system to form a cross-linked network, which is chemically bonded to the final cured coating polymer skeleton in the form of a covalent bond. This effectively prevents the antimicrobial agent from leaching, migrating or volatilizing due to physical wear, solvents or water during use, thereby providing long-term and stable antimicrobial protection. At the same time, this bonding method also makes the antimicrobial agent more evenly distributed in the coating. DETAILED DESCRIPTION

[0009] The following is a clear and complete description of the technical solutions in the embodiments of the present invention. Obviously, the embodiments described are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts are within the scope of protection of the present invention.

[0010] Example 1: The modified antibacterial agent is prepared by the following steps: Step A1, 0.2 mol of p-chlorophenol and 100 mL of water were mixed and stirred to form a mixed solution, 0.1 mol of 1,3-propylenediamine, 0.05 mol of anhydrous potassium carbonate and 100 mL of water were mixed and stirred to form a mixed solution, and then slowly added dropwise to the mixed solution. The mixture was reacted in an ice-water bath for 1 hour, and the temperature was raised to room temperature and stirred for 5 hours. The mixture was filtered, washed, dried, and recrystallized to obtain a phenol derivative. Step A2, 0.05 mol of a phenol derivative and 0.21 mol of paraformaldehyde were added to a mixture of 80 mL of toluene and 20 mL of ethanol, and the mixture was heated to 80° C. under stirring in an oil bath and refluxed for 30 min. Then, 50 mL of a 2-amino-4-methylthiazole toluene solution was slowly added, and the mixture was refluxed for 24 h. The mixture was rotary evaporated and recrystallized to obtain a benzoxazine derivative. The ratio of 2-amino-4-methylthiazole to toluene in the 2-amino-4-methylthiazole toluene solution was 0.1 mol:50 mL; Step A3: A benzoxazine derivative and triethylamine were stirred uniformly in tetrahydrofuran to form a solution 1. 0.01 mol of 4-pentenoyl chloride was stirred uniformly in 50 mL of tetrahydrofuran, and then 50 mL of solution 1 was slowly added. The mixture was stirred in an oil bath at 40° C. for 4 h, filtered, rotary evaporated, washed, filtered twice, and dried to obtain an alkenyl-benzoxazine derivative. The ratio of the benzoxazine derivative, triethylamine, and tetrahydrofuran in solution 1 was 0.01 mol:0.011 mol:50 mL. Step A4: Under nitrogen, 0.01 mol of an alkenyl-benzoxazine derivative was uniformly stirred in a mixture of 70 mL of ethanol and 30 mL of water, 0.01 mol of 1-chlorohexane was slowly added dropwise, and the temperature was raised to 50° C. The mixture was stirred for 12 h, filtered, washed, and dried to obtain a modified antibacterial agent.

[0011] Example 2: The modified antibacterial agent is prepared by the following steps: Step A1, 0.201 mol of p-chlorophenol and 100 mL of water were mixed and stirred to form a mixed solution, 0.1 mol of 1,3-propylenediamine, 0.065 mol of anhydrous potassium carbonate and 100 mL of water were mixed and stirred to form a mixed solution, and then slowly added dropwise to the mixed solution. The mixture was reacted in an ice-water bath for 1.5 hours, and the temperature was raised to room temperature and stirred for 6 hours. The mixture was filtered, washed, dried, and recrystallized to obtain a phenol derivative. Step A2: 0.075 mol of a phenol derivative and 0.3 mol of paraformaldehyde were added to a mixture of 80 mL of toluene and 20 mL of ethanol, and the mixture was heated to 80° C. under stirring in an oil bath and refluxed for 40 min. 50 mL of a 2-amino-4-methylthiazole toluene solution was then slowly added, and the mixture was refluxed for 24 h. The mixture was rotary evaporated and recrystallized to obtain a benzoxazine derivative. The ratio of 2-amino-4-methylthiazole to toluene in the 2-amino-4-methylthiazole toluene solution was 0.15 mol:50 mL. Step A3: A benzoxazine derivative and triethylamine were stirred uniformly in tetrahydrofuran to form a solution 1. 0.015 mol of 4-pentenoyl chloride was stirred uniformly in 50 mL of tetrahydrofuran, and then 50 mL of solution 1 was slowly added. The mixture was stirred in an oil bath at 40°C for 5 h. The mixture was filtered, rotary evaporated, washed, filtered twice, and dried to obtain an alkenyl-benzoxazine derivative. The ratio of the benzoxazine derivative, triethylamine, and tetrahydrofuran in solution 1 was 0.01 mol:0.011 mol:50 mL. Step A4: Under nitrogen, 0.01 mol of an alkenyl-benzoxazine derivative was uniformly stirred in a mixture of 70 mL of ethanol and 30 mL of water, 0.015 mol of n-octyl chloride was slowly added dropwise, and the temperature was raised to 60°C. The mixture was stirred for 15 hours, filtered, washed, and dried to obtain a modified antibacterial agent.

[0012] Example 3: The modified antibacterial agent is prepared by the following steps: Step A1, 0.203 mol of p-chlorophenol and 100 mL of water were mixed and stirred to form a mixed solution, 0.1 mol of 1,3-propylenediamine, 0.08 mol of anhydrous potassium carbonate and 100 mL of water were mixed and stirred to form a mixed solution, and then slowly added dropwise to the mixed solution. The mixture was reacted in an ice-water bath for 2 h, and the temperature was raised to room temperature and stirred for 7 h. The mixture was filtered, washed, dried, and recrystallized to obtain a phenol derivative. Step A2, 0.1 mol of phenol derivative and 0.42 mol of paraformaldehyde were added to a mixture of 80 mL of toluene and 20 mL of ethanol, and the mixture was heated to 80° C. under stirring in an oil bath and refluxed for 50 min. Then, 50 mL of 2-amino-4-methylthiazole toluene solution was slowly added, and the mixture was refluxed for 24 h. The mixture was rotary evaporated and recrystallized to obtain a benzoxazine derivative. The ratio of 2-amino-4-methylthiazole to toluene in the 2-amino-4-methylthiazole toluene solution was 0.2 mol:50 mL; Step A3: A benzoxazine derivative and triethylamine were stirred uniformly in tetrahydrofuran to form a solution 1. 0.02 mol of 4-pentenoyl chloride was stirred uniformly in 50 mL of tetrahydrofuran, and then 50 mL of solution 1 was slowly added. The mixture was stirred in an oil bath at 40° C. for 6 h, filtered, rotary evaporated, washed, filtered twice, and dried to obtain an alkenyl-benzoxazine derivative. The ratio of the benzoxazine derivative, triethylamine, and tetrahydrofuran in solution 1 was 0.01 mol:0.011 mol:50 mL. Step A4: Under nitrogen, 0.01 mol of an alkenyl-benzoxazine derivative was uniformly stirred in a mixture of 70 mL of ethanol and 30 mL of water, 0.02 mol of 1-chlorododecane was slowly added dropwise, and the temperature was raised to 70° C. The mixture was stirred for 18 h, filtered, washed, and dried to obtain a modified antibacterial agent.

[0013] Example 4: A method for preparing a UV-curable water-based coating comprises the following steps: The raw materials were weighed by weight, and 40 parts of aqueous polyurethane acrylate emulsion, 15 parts of aqueous epoxy-modified acrylic resin, 7 parts of the modified antibacterial agent prepared in Example 1, 8 parts of nano-calcium carbonate, 2 parts of photoinitiator 184, 2 parts of silane coupling agent KH560, 0.3 parts of leveling agent BYK-3455, 0.4 parts of defoaming agent BYK-1794, 0.2 parts of dispersant BYK-2013, 3 parts of isopropyl alcohol and 10 parts of water were mixed and stirred to obtain a UV-curable water-based coating.

[0014] Example 5: A method for preparing a UV-curable water-based coating comprises the following steps: The raw materials were weighed by weight, and 45 parts of aqueous polyurethane acrylate emulsion, 20 parts of aqueous epoxy-modified acrylic resin, 10 parts of the modified antibacterial agent prepared in Example 2, 10 parts of white carbon black, 3.5 parts of photoinitiator TPO-L, 3 parts of silane coupling agent KH570, 0.5 parts of leveling agent BYK-3455, 0.6 parts of defoaming agent BYK-1794, 0.4 parts of dispersant BYK-2013, 5 parts of isopropyl alcohol and 12 parts of water were mixed and stirred uniformly to obtain a UV-curable water-based coating.

[0015] Example 6: A method for preparing a UV-curable water-based coating comprises the following steps: The raw materials were weighed by weight, and 50 parts of aqueous polyurethane acrylate emulsion, 25 parts of aqueous epoxy-modified acrylic resin, 12 parts of the modified antibacterial agent prepared in Example 3, 12 parts of white carbon black, 5 parts of photoinitiator TPO-L, 4 parts of silane coupling agent KH570, 0.6 parts of leveling agent BYK-3455, 0.8 parts of defoaming agent BYK-1794, 0.5 parts of dispersant BYK-2013, 7 parts of isopropyl alcohol and 15 parts of water were mixed and stirred uniformly to obtain a UV-curable water-based coating.

[0016] Comparative Example 1: This comparative example is a UV-curable water-based coating. The difference from Example 6 is that the modified antibacterial agent prepared in Example 3 is replaced by a quaternary ammonium salt antibacterial agent dodecyldimethylbenzyl ammonium chloride, and the rest are the same.

[0017] Comparative Example 2: This comparative example is a UV-curable water-based coating. The difference from Example 6 is that the alkenyl-benzoxazine derivative prepared in Example 3 is used instead of the modified antibacterial agent prepared in Example 3. The rest are the same.

[0018] Comparative Example 3: This comparative example is a UV-curable water-based coating. The difference from Example 6 is that the benzoxazine derivative prepared in Example 3 is used instead of the modified antibacterial agent prepared in Example 3. The rest are the same.

[0019] The UV curable waterborne coatings prepared in Examples 4-6 and Comparative Examples 1-3 were subjected to performance tests: Antibacterial performance test: Tested in accordance with the HG / T 3950-2007 method, where when the antibacterial rate is ≥99%, the antibacterial performance is Class I; when ≥90%, the antibacterial performance is Class II; when the antibacterial rate is ≥95%, the antibacterial durability is Class I, and when ≥85%, the antibacterial durability is Class II; Mildew growth level: Class 0 - no growth, i.e. no growth observed under a microscope; Class 1 - trace growth, with growth coverage area less than 10%; Class 2 - growth coverage area greater than 10%; when the antibacterial durability is Class I, the mildew growth level is Class 0; when the antibacterial durability is Class II, the mildew growth level is Class 1.

[0020] The test results are shown in Table 1: Table 1: Performance test results

[0021] As can be seen from Table 1, the UV-curable water-based coatings prepared by the present invention have an antibacterial rate greater than 99% after antibacterial performance testing, and the antibacterial performance and antibacterial durability are both level I, the mildew growth level is both level 0, and the antibacterial durability is both level I, indicating that the coating has excellent antibacterial performance after curing.

[0022] The above content is merely an example and explanation of the concept of the present invention. Those skilled in the art may make various modifications or additions to the described specific embodiments or replace them in a similar manner. As long as they do not deviate from the scope defined by the concept of the invention, they should all fall within the scope of protection of the present invention.

Claims

1. A UV curing water-based coating, characterized in that: The invention comprises the following raw materials in parts by weight: 40-50 parts of waterborne polyurethane acrylate emulsion, 15-25 parts of waterborne epoxy modified acrylic resin, 7-12 parts of modified antibacterial agent, 8-12 parts of inorganic filler, 2-4 parts of silane coupling agent, 2-5 parts of photoinitiator, 0.3-0.6 parts of leveling agent, 0.4-0.8 parts of defoaming agent, 0.2-0.5 parts of dispersant, 3-7 parts of isopropyl alcohol and 10-15 parts of water; The modified antibacterial agent is prepared by reacting an alkenyl-benzoxazine derivative with a chloroalkane, the alkenyl-benzoxazine derivative is prepared by reacting a benzoxazine derivative with 4-pentenoyl chloride, the benzoxazine derivative is prepared by reacting a phenol derivative, paraformaldehyde and 2-amino-4-methylthiazole, and the phenol derivative is prepared by reacting p-chlorophenol 1,3-propylenediamine.

2. A UV curing water-based coating according to claim 1, characterized in that, The modified antibacterial agent is prepared by the following steps: Step A1, p-chlorophenol and water are mixed and stirred to form a mixed solution, 1,3-propylenediamine, anhydrous potassium carbonate and water are mixed and stirred to form a mixed solution, and then slowly added dropwise to the mixed solution. The mixture is reacted in an ice-water bath for 1-2 hours, the temperature is raised to room temperature and stirred for 5-7 hours, and the mixture is filtered, washed, dried and recrystallized to obtain a phenol derivative; Step A2: adding a phenol derivative and paraformaldehyde to a mixture of toluene and ethanol, heating the mixture to 80° C. under stirring in an oil bath and reflux for 30-50 minutes, then slowly adding a 2-amino-4-methylthiazole toluene solution, reflux for 24 hours, rotary evaporation, and recrystallization to obtain a benzoxazine derivative; Step A3: A benzoxazine derivative and triethylamine are stirred uniformly in tetrahydrofuran to form a solution 1. 4-pentenoyl chloride is stirred uniformly in tetrahydrofuran, and then the solution 1 is slowly added. The mixture is stirred in an oil bath at 40°C for 4-6 hours, filtered, rotary evaporated, washed, filtered a second time, and dried to obtain an alkenyl-benzoxazine derivative. Step A4: Under nitrogen, stir the alkenyl-benzoxazine derivative in a mixture of ethanol and water, slowly add chloroalkane dropwise, and heat to 50-70°C. Stir and react for 12-18 hours. Filter, wash, and dry to obtain the modified antibacterial agent.

3. A UV curing water-based coating according to claim 2, characterized in that, In step A1, the molar ratio of p-chlorophenol, 1,3-propylenediamine and anhydrous potassium carbonate is 0.2-0.203:0.1:0.05-0.

08.

4. A UV curable water-based coating according to claim 2, characterized in that: In step A2, the usage ratio of the phenol derivative, paraformaldehyde, toluene, ethanol and 2-amino-4-methylthiazole toluene solution is 0.05-0.1 mol:0.21-0.42 mol:80 mL:20 mL:50 mL.

5. A UV curable water-based coating according to claim 2, characterized in that, The ratio of 2-amino-4-methylthiazole to toluene in the 2-amino-4-methylthiazole toluene solution in step A2 is 0.1-0.2 mol:50 mL.

6. A UV curable water-based coating according to claim 2, characterized in that: In step A3, the usage ratio of 4-pentenoyl chloride, tetrahydrofuran, and solution 1 is 0.01-0.02 mol:50 mL:50 mL.

7. A UV curable water-based coating according to claim 2, characterized in that: The amount ratio of the benzoxazine derivative, triethylamine and tetrahydrofuran in the solution 1 of step A3 is 0.01 mol:0.011 mol:50 mL.

8. A UV curable water-based coating according to claim 2, characterized in that: In step A4, the ratio of the alkenyl-benzoxazine derivative, ethanol, water and chloroalkane is 0.01 mol:70 mL:30 mL:0.01-0.02 mol, and the chloroalkane is one of 1-chlorododecane, n-octyl chloride, 1-chlorodecane or 1-chlorohexane.

9. A UV curable water-based coating according to claim 1, characterized in that: The inorganic filler is one of nano calcium carbonate or white carbon black, the silane coupling agent is one of KH560 or KH570, and the photoinitiator is one of photoinitiator 184 or photoinitiator TPO-L.

10. A method for preparing the UV curable water-based coating according to any one of claims 1 to 9, characterized in that: The following steps are involved: The raw materials are weighed in parts by weight, and the waterborne polyurethane acrylate emulsion, waterborne epoxy modified acrylic resin, modified antibacterial agent, inorganic filler, photoinitiator, silane coupling agent, leveling agent, defoaming agent, dispersant, isopropyl alcohol and water are mixed and stirred uniformly to obtain a UV curing waterborne coating.

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