A UV-curable waterborne coating and a method for preparing the same

Abstract

The present application relates to the paint technical field, disclose a kind of UV curing water-based paint and preparation method thereof.The UV curing water-based paint in the present application is with water-based polyurethane acrylate emulsion and water-based epoxy modified acrylic resin as main raw material, and adds modified antibacterial agent, inorganic filler, photoinitiator, silane coupling agent and other functional additives and is formed.Meanwhile, modified antibacterial agent utilizes the synergistic effect between benzoxazine structure, quaternary ammonium salt structure, thiazole structure and carbon-carbon double bond, gives coating excellent antibacterial property, widens the application field of coating, so that it has certain application prospect in wooden furniture, plastic products, printing and packaging etc.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of paint technology, and in particular to a UV-cured water-based paint and a preparation method thereof. BACKGROUND

[0002] With the increasingly stringent environmental regulations and the improvement of consumer health awareness, water-based paint has become an important substitute for traditional solvent-based paint due to its low VOC (volatile organic compound) characteristics. Among them, UV-cured water-based paint combines the environmental advantages of water-based system and the high efficiency (second-level curing, low energy consumption) of UV curing technology, and is widely used in wood, plastic, metal, packaging printing and other fields. However, in the application scenarios with high humidity and high contact frequency (such as medical equipment, furniture surface, food packaging, etc.), microorganisms such as bacteria and mold are easy to breed on the surface of the coating, which not only affects the appearance, but also may cause health and safety problems. Therefore, the development of UV-cured water-based paint with long-acting antibacterial function has become an important research direction in the industry.

[0003] Traditional water-based paint improves the antibacterial performance of the paint by adding organic antibacterial agents, inorganic antibacterial agents or natural antibacterial agents, but all have some shortcomings, such as: quaternary ammonium salt organic antibacterial agent, although it has a wide antibacterial spectrum, but it is easy to migrate and precipitate, resulting in short antibacterial life; inorganic antibacterial agent (nano-silver, zinc ion), although it has good heat resistance, but it is easy to agglomerate and affect the dispersibility, high addition amount may hinder the UV curing reaction and reduce the mechanical properties of the coating; natural antibacterial agent (chitosan), although it has high safety, but it has poor weather resistance and is easy to be degraded by UV. Therefore, in order to break through the above limitations, researchers improve the comprehensive performance of antibacterial agents through chemical structure modification, so that they have long-acting antibacterial and non-migration characteristics in UV-cured water-based paint. SUMMARY

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

[0005] The object of the present application can be achieved by the following technical solutions:

[0006] A UV-cured water-based paint, comprising the following raw materials by weight: water-based polyurethane acrylate emulsion 40-50 parts, water-based epoxy modified acrylic resin 15-25 parts, modified antibacterial agent 7-12 parts, inorganic filler 8-12 parts, silane coupling agent 2-4 parts, photoinitiator 2-5 parts, leveling agent 0.3-0.6 parts, defoaming agent 0.4-0.8 parts, dispersing agent 0.2-0.5 parts, isopropyl alcohol 3-7 parts, water 10-15 parts;

[0007] Further, the inorganic filler is one of nano calcium carbonate or white carbon black;

[0008] Further, the silane coupling agent is one of KH560 or KH570;

[0009] Further, the photoinitiator is one of photoinitiator 184 or photoinitiator TPO-L;

[0010] Further, the leveling agent is leveling agent BYK-3455;

[0011] Further, the defoaming agent is defoaming agent BYK-1794;

[0012] Further, the dispersing agent is dispersing agent BYK-2013;

[0013] The modified antibacterial agent is prepared by the following steps:

[0014] Step A1, uniformly mix p-chlorophenol and water to form a mixed solution, uniformly mix 1,3-propanediamine, anhydrous potassium carbonate and water, then slowly add to the mixed solution, react for 1-2h under ice water bath, warm to room temperature and stir for 5-7h, filter, wash, dry, recrystallize, and the phenol derivative is obtained;

[0015] Further, in step A1, the molar ratio of p-chlorophenol, 1,3-propanediamine and anhydrous potassium carbonate is 0.2-0.203:0.1:0.05-0.08;

[0016] Step A2, add the phenol derivative and paraformaldehyde to a mixed solution of toluene and ethanol, and stir under oil bath to warm to 80℃ and reflux for 30-50min, then slowly add 2-amino-4-methylthiazole toluene solution, reflux for 24h, rotary evaporation, recrystallize, and the benzoxazine derivative is obtained;

[0017] Further, in step A2, the amount ratio of the phenol derivative, paraformaldehyde, toluene, ethanol and 2-amino-4-methylthiazole toluene solution is 0.05-0.1mol:0.21-0.42mol:80mL:20mL:50mL;

[0018] Further, in step A2, the amount ratio of 2-amino-4-methylthiazole and toluene in the 2-amino-4-methylthiazole toluene solution is 0.1-0.2mol:50mL;

[0019] Step A3, uniformly stir the benzoxazine derivative and triethylamine in tetrahydrofuran to form solution 1, uniformly stir 4-pentenoyl chloride in tetrahydrofuran, then slowly add to solution 1, constant temperature stir for 4-6h in a 40℃ oil bath, filter, rotary evaporation, wash, secondary filtration, dry, and the alkenyl-benzoxazine derivative is obtained;

[0020] Further, in step A3, the use amount ratio of 4-pentenoyl chloride, tetrahydrofuran and solution 1 is 0.01-0.02 mol: 50 mL: 50 mL;

[0021] Further, in solution 1 of step A3, the use amount ratio of benzoxazine derivative, triethylamine and tetrahydrofuran is 0.01 mol: 0.011 mol: 50 mL;

[0022] Step A4, under the condition of nitrogen, the alkenyl-benzoxazine derivative is stirred in the mixture of ethanol and water, chloroalkane is slowly added dropwise, and the temperature is increased to 50-70 DEG C, and the reaction is stirred for 12-18 h, and then filtered, washed and dried to obtain the modified antibacterial agent.

[0023] Further, in step A4, the use amount ratio of alkenyl-benzoxazine derivative, ethanol, water and chloroalkane is 0.01 mol: 70 mL: 30 mL: 0.01-0.02 mol.

[0024] Further, in step A4, the chloroalkane is one of 1-chlorododecane, n-octyl chloride, 1-chlorodecane or 1-chlorohexane.

[0025] A preparation method of UV-cured water-based paint comprises the following steps:

[0026] The raw materials are weighed by weight parts, and the water-based polyurethane acrylate emulsion, the water-based epoxy modified acrylic resin, the modified antibacterial agent, the inorganic filler, the photoinitiator, the silane coupling agent, the leveling agent, the defoaming agent, the dispersant, the isopropyl alcohol and the water are mixed and stirred uniformly to obtain the UV-cured water-based paint.

[0027] The present application has the following advantages:

[0028] The UV-cured water-based paint in the present application is prepared by using the water-based polyurethane acrylate emulsion and the water-based epoxy modified acrylic resin as main raw materials, and adding the modified antibacterial agent, the inorganic filler, the photoinitiator, the silane coupling agent and other functional additives.

[0029] The modified antibacterial agent prepared by the application utilizes the synergistic effect among the benzoxazine structure, the quaternary ammonium salt structure, the thiazole structure and the carbon-carbon double bond, and gives the coating a fast sterilization and long-acting antibacterial performance. The benzoxazine structure can destroy the integrity of the bacterial cell membrane when contacting the bacteria, leading to the death of the bacteria; the thiazole ring is an aromatic ring containing nitrogen, carbon, sulfur and other elements, has strong electrophilicity and nucleophilicity, and can interact with the key components in the bacterial cells, thereby showing strong bactericidal effect; and the quaternary ammonium salt structure, as a common antibacterial component, can synergistically act with the thiazole ring and the benzoxazine structure, and further improve the antibacterial performance of the base. In addition, the presence of the carbon-carbon double bond structure enables the modified antibacterial agent to participate in the curing of the base, and under the action of the initiator and UV light, the modified antibacterial agent can occur a free radical polymerization reaction with a large number of acrylate double bonds in the coating system, form a crosslinked network, and be chemically bonded to the polymer skeleton of the finally formed cured coating in the form of a covalent bond, effectively preventing the leaching, migration or volatilization of the antibacterial agent in the use process due to physical abrasion, solvent or water, thereby providing long-term and stable antibacterial protection. Meanwhile, this bonding mode also makes the antibacterial agent more uniformly distributed in the coating. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the application, rather than all the embodiments. Based on the embodiments in the application, all other embodiments obtained by those skilled in the art without creative work fall within the protection scope of the application.

[0031] Embodiment 1: The modified antibacterial agent is prepared by the following steps:

[0032] Step A1, 0.2 mol of p-chlorophenol and 100 mL of water are mixed and stirred uniformly to form a mixed solution, 0.1 mol of 1,3-propanediamine, 0.05 mol of anhydrous potassium carbonate and 100 mL of water are mixed and stirred uniformly, and then slowly added dropwise into the mixed solution, reacted for 1 h under an ice water bath, stirred for 5 h after warming to room temperature, filtered, washed, dried, recrystallized, and the phenol derivative is obtained;

[0033] Step A2, 0.05 mol of the phenol derivative and 0.21 mol of paraformaldehyde are added into a mixed solution of 80 mL of toluene and 20 mL of ethanol, and stirred under an oil bath to warm to 80℃ and reflux for 30 min, then 50 mL of 2-amino-4-methylthiazole toluene solution is slowly added, and refluxed for 24 h, and then rotary evaporated and recrystallized, and the benzoxazine derivative is obtained, the amount ratio of 2-amino-4-methylthiazole to toluene in the 2-amino-4-methylthiazole toluene solution is 0.1 mol:50 mL;

[0034] Step A3, stirring 0.01 mol of the benoxazin derivative and triethylamine in 50 mL of tetrahydrofuran to form a solution 1, stirring 0.01 mol of 4-pentenoyl chloride in 50 mL of tetrahydrofuran, slowly adding 50 mL of the solution 1, stirring in a 40°C oil bath for 4 h, filtering, rotary evaporation, washing, twice filtering, and drying to obtain the alkenyl-benoxazin derivative, the amount ratio of the benoxazin derivative, triethylamine, and tetrahydrofuran in the solution 1 being 0.01 mol:0.011 mol:50 mL;

[0035] Step A4, stirring 0.01 mol of the alkenyl-benoxazin derivative in a mixture of 70 mL of ethanol and 30 mL of water under the condition of nitrogen, slowly adding 0.01 mol of 1-chlorohexane, and increasing the temperature to 50°C, stirring for 12 h, filtering, washing, and drying to obtain the modified antibacterial agent.

[0036] Example 2: The modified antibacterial agent is prepared by the following steps:

[0037] Step A1, stirring 0.201 mol of p-chlorophenol and 100 mL of water to form a mixture, stirring 0.1 mol of 1,3-propanediamine, 0.065 mol of anhydrous potassium carbonate, and 100 mL of water, slowly adding the mixture to the mixture under the ice water bath, reacting for 1.5 h, increasing the temperature to room temperature and stirring for 6 h, filtering, washing, drying, and recrystallizing to obtain the phenol derivative;

[0038] Step A2, stirring 0.075 mol of the phenol derivative and 0.3 mol of paraformaldehyde in a mixture of 80 mL of toluene and 20 mL of ethanol, and stirring under the oil bath to increase the temperature to 80°C and reflux for 40 min, slowly adding 50 mL of a 2-amino-4-methylthiazole toluene solution, refluxing for 24 h, rotary evaporation, and recrystallizing to obtain the benoxazin derivative, the amount ratio of 2-amino-4-methylthiazole and toluene in the 2-amino-4-methylthiazole toluene solution being 0.15 mol:50 mL;

[0039] Step A3, stirring 0.01 mol of the benoxazin derivative and triethylamine in 50 mL of tetrahydrofuran to form a solution 1, stirring 0.015 mol of 4-pentenoyl chloride in 50 mL of tetrahydrofuran, slowly adding 50 mL of the solution 1, stirring in a 40°C oil bath for 5 h, filtering, rotary evaporation, washing, twice filtering, and drying to obtain the alkenyl-benoxazin derivative, the amount ratio of the benoxazin derivative, triethylamine, and tetrahydrofuran in the solution 1 being 0.01 mol:0.011 mol:50 mL;

[0040] Step A4, under nitrogen condition, 0.01 mol of the alkenyl-benzoxazine derivative was stirred in a mixture of 70 mL of ethanol and 30 mL of water, 0.02 mol of 1-chlorododecane was added dropwise slowly, and the temperature was raised to 70 °C, and the reaction was stirred for 18 h. The product was filtered, washed, and dried to obtain the modified antibacterial agent.

[0041] Example 3: The modified antibacterial agent was prepared by the following steps:

[0042] Step A1, 0.203 mol of p-chlorophenol was mixed with 100 mL of water to form a mixture, and 0.1 mol of 1,3-propanediamine, 0.08 mol of anhydrous potassium carbonate, and 100 mL of water were mixed to form another mixture. The second mixture was added dropwise slowly to the first mixture under an ice-water bath for 2 h, and then the temperature was raised to room temperature and stirred for 7 h. The product was filtered, washed, and dried, and then recrystallized to obtain the phenol derivative.

[0043] Step A2, 0.1 mol of the 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 temperature was raised to 80 °C under an oil bath to reflux for 50 min. Then 50 mL of a 2-amino-4-methylthiazole toluene solution was added slowly, and the reaction was refluxed for 24 h. The product was rotary evaporated and recrystallized to obtain the benzoxazine derivative. The amount ratio of 2-amino-4-methylthiazole to toluene in the 2-amino-4-methylthiazole toluene solution was 0.2 mol:50 mL.

[0044] Step A3, the benzoxazine derivative and triethylamine were stirred in tetrahydrofuran to form a solution 1. 0.02 mol of 4-pentenoyl chloride was stirred in 50 mL of tetrahydrofuran, and then added slowly to 50 mL of solution 1. The temperature was kept at 40 °C in an oil bath for 6 h. The product was filtered, rotary evaporated, washed, filtered twice, and dried to obtain the alkenyl-benzoxazine derivative. The amount ratio of the benzoxazine derivative, triethylamine, and tetrahydrofuran in solution 1 was 0.01 mol:0.011 mol:50 mL.

[0045] Step A4, under nitrogen condition, 0.01 mol of the alkenyl-benzoxazine derivative was stirred in a mixture of 70 mL of ethanol and 30 mL of water, 0.02 mol of 1-chlorododecane was added dropwise slowly, and the temperature was raised to 70 °C, and the reaction was stirred for 18 h. The product was filtered, washed, and dried to obtain the modified antibacterial agent.

[0046] Example 4: A method for preparing a UV-curable water-based paint includes the following steps:

[0047] The raw materials were weighed by parts by weight, and 40 parts of waterborne polyurethane acrylate emulsion, 15 parts of waterborne epoxy modified acrylic resin, 7 parts of 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 uniformly to obtain the UV curing water-based paint.

[0048] Example 5: A preparation method of a UV curing water-based paint comprises the following steps:

[0049] The raw materials were weighed by parts by weight, and 45 parts of waterborne polyurethane acrylate emulsion, 20 parts of waterborne epoxy modified acrylic resin, 10 parts of 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 the UV curing water-based paint.

[0050] Example 6: A preparation method of a UV curing water-based paint comprises the following steps:

[0051] The raw materials were weighed by parts by weight, and 50 parts of waterborne polyurethane acrylate emulsion, 25 parts of waterborne epoxy modified acrylic resin, 12 parts of 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 the UV curing water-based paint.

[0052] Comparative Example 1: This comparative example is a UV curing water-based paint, which is different from Example 6 in that the quaternary ammonium salt antibacterial agent dodecyl dimethyl benzyl ammonium chloride is used instead of the modified antibacterial agent prepared in Example 3, and the rest are the same.

[0053] Comparative Example 2: This comparative example is a UV curing water-based paint, which is different from Example 6 in that the alkenyl-benzoxazine derivative prepared in Example 3 is used instead of the modified antibacterial agent prepared in Example 3, and the rest are the same.

[0054] Comparative Example 3: This comparative example is a UV curing water-based paint, which is different from Example 6 in that the benzoxazine derivative prepared in Example 3 is used instead of the modified antibacterial agent prepared in Example 3, and the rest are the same.

[0055] The UV curing water-based paints prepared in Examples 4-6 and Comparative Examples 1-3 were tested for performance:

[0056] Antibacterial performance test: the test is carried out according to the method of HG / T 3950-2007, wherein the antibacterial rate is greater than or equal to 99%, the antibacterial performance is I grade; the antibacterial rate is greater than or equal to 90%, the antibacterial performance is II grade; the antibacterial durability is I grade when the antibacterial rate is greater than or equal to 95%, and the antibacterial durability is II grade when the antibacterial rate is greater than or equal to 85%; the mildew growth level is 0 grade-no growth, i.e. no growth is observed under a microscope; 1 grade-trace growth, the growth coverage area is less than 10%; 2 grade-the growth coverage area is greater than 10%; the mildew growth level is 0 grade when the mildew resistance is I grade; the mildew growth level is 1 grade when the mildew resistance is II grade.

[0057] The test results are shown in Table 1:

[0058] Table 1: Performance test results

[0059]

[0060] As shown in Table 1, the UV-cured water-based paint prepared by the present application has an antibacterial rate greater than 99% after the antibacterial performance test, the antibacterial performance and the antibacterial durability are both I grade, the mildew growth level is 0 grade, and the mildew resistance is I grade, which indicates that the paint after curing has excellent antibacterial performance.

[0061] The above content is only an example and description of the present application, and those skilled in the art can make various modifications or supplements or use similar ways to replace the described specific embodiments, as long as the modifications or supplements or replacements do not deviate from the scope defined by the concept of the present application, and all of them shall belong to the protection scope of the present application.

Claims

1. A UV-curable water-based coating, characterized in that, The raw materials include the following 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 defoamer, 0.2-0.5 parts of dispersant, 3-7 parts of isopropanol, and 10-15 parts of water; The modified antibacterial agent is prepared by the following steps: Step A1: Mix p-chlorophenol and water until homogeneous to form a mixture. Mix 1,3-propanediamine, anhydrous potassium carbonate and water until homogeneous, and slowly add them dropwise to the mixture. React in an ice-water bath for 1-2 hours, then heat to room temperature and stir for 5-7 hours. Filter, wash, dry and recrystallize to obtain the phenol derivative. Step A2: Add phenol derivative and paraformaldehyde to a mixture of toluene and ethanol, stir and heat to 80°C in an oil bath and reflux for 30-50 min, then slowly add 2-amino-4-methylthiazole toluene solution, reflux for 24 h, rotary evaporate and recrystallize to obtain benzoxazine derivative. Step A3: Stir the benzoxazine derivative and triethylamine in tetrahydrofuran to form solution 1. Stir 4-pentenoyl chloride in tetrahydrofuran and slowly add it to solution 1. Stir at a constant temperature in an oil bath at 40°C for 4-6 hours. Filter, rotary evaporate, wash, filter again, and dry to obtain alkenyl-benzoxazine derivative. Step A4: Under nitrogen conditions, the alkenyl-benzoxazine derivative is stirred evenly in a mixture of ethanol and water, chloroalkanes are slowly added dropwise, and the temperature is raised to 50-70℃. The mixture is stirred for 12-18 hours, filtered, washed, and dried to obtain the modified antibacterial agent.

2. The UV-curable waterborne coating according to claim 1, characterized in that, In step A1, the molar ratio of p-chlorophenol, 1,3-propanediamine and anhydrous potassium carbonate is 0.2-0.203:0.1:0.05-0.

08.

3. The UV-curable waterborne coating according to claim 1, characterized in that, 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.

4. The UV-curable waterborne coating according to claim 1, characterized in that, In step A2, the ratio of 2-amino-4-methylthiazole to toluene in the 2-amino-4-methylthiazole toluene solution is 0.1-0.2 mol: 50 mL.

5. The UV-curable waterborne coating according to claim 1, characterized in that, In step A3, the ratio of 4-pentenoyl chloride, tetrahydrofuran, and solution 1 is 0.01-0.02 mol: 50 mL: 50 mL.

6. The UV-curable waterborne coating according to claim 1, characterized in that, In step A3, the ratio of benzoxazine derivative, triethylamine, and tetrahydrofuran in solution 1 is 0.01 mol: 0.011 mol: 50 mL.

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

8. The UV-curable waterborne coating according to claim 1, characterized in that, The inorganic filler is either nano-calcium carbonate or white carbon black, the silane coupling agent is either KH560 or KH570, and the photoinitiator is either photoinitiator 184 or photoinitiator TPO-L.

9. A method for preparing a UV-curable waterborne coating according to any one of claims 1-8, characterized in that, Includes the following steps: Weigh the raw materials according to the weight proportions, and mix and stir the waterborne polyurethane acrylate emulsion, waterborne epoxy modified acrylic resin, modified antibacterial agent, inorganic filler, photoinitiator, silane coupling agent, leveling agent, defoamer, dispersant, isopropanol and water evenly to obtain UV-curable waterborne coating.

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