A self-drying acrylic magnetic paint and a preparation method thereof

Abstract

The application belongs to the technical field of paint, and particularly relates to a self-drying acrylic enamel and a preparation method thereof. The acrylic enamel provided by the application comprises component A and component B; the component A comprises the following components in parts by weight: 50-60 parts of hydroxyl acrylic resin; 15-20 parts of water-based polyurethane emulsion; 10-15 parts of pigment and filler; 8-10 parts of montmorillonite compound; 4-6 parts of coupling agent; 1-2 parts of leveling agent; 0.5-1 part of dispersing agent; 0.3-0.5 part of defoaming agent; and 40-50 parts of deionized water; the component B comprises the following components in parts by weight: 15-20 parts of curing agent; the hydroxyl acrylic resin is used as the main component in the application, normal-temperature rapid drying can be realized, the environmental protection performance is good, through the addition of the montmorillonite compound, good hardness, impact resistance, corrosion resistance, aging resistance, antibacterial performance and adhesion are obtained, and the application is suitable for fields such as ships, airplanes, high-speed rails and ocean engineering.

Description

Technical Field

[0001] This invention belongs to the field of coating technology, specifically relating to a self-drying acrylic enamel and its preparation method. Background Technology

[0002] Enamel, also known as porcelain varnish, is a coating made by mixing varnish as a base with pigments, solvents, and additives. After drying, it forms a smooth and hard coating with excellent weather resistance, chemical corrosion resistance, and decorative properties. It is suitable for various substrates such as chemical equipment, outdoor metal facilities, ships, marine engineering, and household appliances. Enamel is mainly divided into two categories: water-based enamel and oil-based enamel. Oil-based enamel has poor environmental performance, as its components contain a large amount of volatile organic compounds, which can easily irritate human skin, eyes, and respiratory system, pose a carcinogenic risk, and even cause nerve damage. It also seriously harms the environmental ecosystem. Water-based enamel, on the other hand, uses water as a diluent, does not contain benzene, formaldehyde, or other harmful substances, is non-toxic and odorless, and has better environmental performance. It is gradually replacing oil-based enamel as a new development direction.

[0003] Chinese patent application CN202310617173.7 discloses a high flash point safe alkyd enamel and its preparation method. The alkyd enamel comprises the following raw materials in parts by weight: 60-100 parts alkyd resin, 10-20 parts diacetone alcohol, 5-10 parts epoxidized soybean oil acrylate, 1-3 parts pigment, 0.5-1.5 parts drier, and 6-8 parts water. This patent uses alkyd resin, pigment, and drier as the base material and introduces diacetone alcohol and epoxidized soybean oil acrylate, thereby improving the flash point and safety performance of the alkyd enamel. Chinese patent application CN202410475125.3 discloses an alkyd external enamel and its preparation method. The alkyd external enamel comprises the following raw materials in parts by weight: bio-based... The patent describes a bio-based coating with high flash point, high adhesion, high aging resistance, and high wear resistance, achieved through the interaction between various raw materials. The coating contains 40-90 parts of high flash point alkyd resin, 1-4 parts of coupling agent, 10-40 parts of pigments and fillers, 0.2-0.8 parts of anti-sagging agent, 1-4 parts of additives, and 6-20 parts of high flash point solvent. The pigments and fillers are nano-titanium dioxide, nano-zinc oxide, and alumina. The additives include at least one of dispersant, drier, anti-skinning agent, leveling agent, and defoamer. The patent describes how the enamel raw materials provided by the patent require the addition of driers to increase the drying speed of the paint film. Strict control of the drier dosage is necessary, as excessive driers can cause paint film quality problems. Furthermore, the patent contains large amounts of organic solvents, classifying it as an oil-based enamel with poor environmental performance.

[0004] Therefore, it is necessary to develop a self-drying, environmentally friendly water-based enamel that does not contain a drying agent to meet the market's demand for high environmental friendliness in enamel. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing technologies by providing a self-drying acrylic enamel and its preparation method. The acrylic enamel provided by this invention uses hydroxyl acrylic resin as the main component. Under the action of a curing agent, it can achieve rapid drying at room temperature, contains no organic solvents, and has good environmental performance. By adding montmorillonite composite, the overall performance of the acrylic enamel is improved, thereby obtaining an acrylic enamel coating with good hardness, impact resistance, corrosion resistance, aging resistance, antibacterial properties, and good adhesion to steel plate substrates. It is suitable for fields such as shipbuilding, aircraft, high-speed rail, and marine engineering.

[0006] The technical solution adopted by the present invention to achieve the above objectives is as follows:

[0007] A self-drying acrylic enamel includes component A and component B; component A comprises the following components by weight: 50-60 parts of hydroxyl acrylic resin; 15-20 parts of waterborne polyurethane emulsion; 10-15 parts of pigments and fillers; 8-10 parts of montmorillonite composite; 4-6 parts of coupling agent; 1-2 parts of leveling agent; 0.5-1 part of dispersant; 0.3-0.5 parts of defoamer; and 40-50 parts of deionized water; component B comprises the following components by weight: 15-20 parts of curing agent.

[0008] Furthermore, the preparation method of the montmorillonite complex is as follows: sodium montmorillonite is added to deionized water and stirred evenly, modified carboxymethyl chitosan is added, and the mixture is stirred and reacted at a temperature of 50-60℃ for 5-6 hours to obtain the montmorillonite complex.

[0009] Furthermore, the mass ratio of sodium montmorillonite to modified carboxymethyl chitosan is 1:0.8-1.

[0010] Further, the preparation method of the modified carboxymethyl chitosan is as follows: carboxymethyl chitosan is added to the reaction solvent, stirred evenly, triethylamine and a modifier are added, and the mixture is stirred and reacted at a temperature of 60-70°C for 6-8 hours to obtain modified carboxymethyl chitosan; the modifier is composed of 5-chlorobenzotriazole and quaternary phosphonium salt monomers in a mass ratio of 1:1.

[0011] Further, the mass ratio of carboxymethyl chitosan, modifier, and triethylamine is 1:0.3-0.4:0.1-0.15; the reaction solvent is a 50-60 wt% ethanol solution.

[0012] Further, the method for preparing the quaternary phosphonium salt monomer is as follows: triphenylphosphine is added to N,N-dimethylformamide, stirred evenly, and under nitrogen protection, (1,3-dichloropropyl)benzene is added at 115-120℃, and then the reaction is continued to be stirred for 22-24 hours to obtain the antibacterial quaternary phosphonium salt.

[0013] Furthermore, the molar ratio of triphenylphosphine to (1,3-dichloropropyl)benzene is 1:1.1-1.2.

[0014] Furthermore, the pigments and fillers are any one or a mixture of several of titanium dioxide, zinc oxide, mica powder, and talc powder; the fineness of the pigments and fillers is ≤20μm.

[0015] Furthermore, the coupling agent is isocyanate-propyltriethoxysilane or 3-isocyanate-propyltrimethoxysilane.

[0016] Furthermore, the leveling agent is any one or a mixture of several of EFKA-3030, BYK-345, and BYK-323.

[0017] Furthermore, the dispersant is any one or a mixture of several of BYK-103, BYK-106, and BYK-107.

[0018] Furthermore, the defoamer is any one or a mixture of several of EFKA-2020, EFKA-2722, and BYK-1794.

[0019] Furthermore, the curing agent is hexamethylene diisocyanate trimer.

[0020] This invention also provides a method for preparing a self-drying acrylic enamel, comprising the following steps: according to the weight ratio, first, hydroxyl acrylic resin and waterborne polyurethane emulsion are mixed evenly, then pigments, fillers, montmorillonite composite, coupling agent and deionized water are added, and stirred for 30-40 minutes, and finally, leveling agent, dispersant and defoamer are added, and stirred for 10-15 minutes to obtain component A; component B curing agent is added to component A, and stirred for 15-20 minutes to obtain acrylic enamel.

[0021] Furthermore, during the preparation of acrylic enamel, the stirring speed is controlled within the range of 1000-1200 r / min.

[0022] The present invention has the following beneficial effects:

[0023] 1. This invention uses carboxymethyl chitosan as a raw material for modification. The amino groups in the carboxymethyl chitosan molecule react with the chlorine atoms in 5-chlorobenzotriazole and quaternary phosphonium salt monomers, thereby grafting 5-chlorobenzotriazole and quaternary phosphonium salt monomers onto the carboxymethyl chitosan molecule to obtain modified carboxymethyl chitosan. The modified carboxymethyl chitosan obtained by this invention contains carboxymethyl chitosan molecules with antibacterial activity and good film-forming properties, quaternary phosphonium salt groups with antibacterial activity, and benzimidazole groups with anti-aging properties. Furthermore, this invention uses a cation exchange reaction to further chemically bond sodium montmorillonite and the quaternary phosphonium salt groups in the modified carboxymethyl chitosan, obtaining a montmorillonite complex.

[0024] 2. Montmorillonite in the montmorillonite composite can improve the suspension stability of acrylic enamel. The uniformly dispersed montmorillonite flakes can effectively fill the micropores of the paint film, improve the density of the paint film, and can also work with carboxymethyl chitosan molecular chains to increase the crosslinking density of the paint film, thereby helping to improve the corrosion resistance of acrylic enamel. In particular, the carboxymethyl chitosan molecules and quaternary phosphonium salt groups in the montmorillonite composite can significantly improve the antibacterial properties of acrylic enamel, and the benzimidazole groups can improve the aging resistance of acrylic enamel. The multiple rigid benzene ring structures in the quaternary phosphonium salt groups can also be dispersed in the paint film during the crosslinking process, improving the hardness and impact resistance of acrylic enamel.

[0025] 3. The acrylic enamel provided by this invention uses hydroxyl acrylic resin as the main component. Under the action of a curing agent, it can achieve rapid drying at room temperature. It does not contain organic solvents and has good environmental performance. By adding montmorillonite composite, the comprehensive performance of the acrylic enamel is improved, thereby obtaining an acrylic enamel coating with good hardness, impact resistance, corrosion resistance, aging resistance, antibacterial properties, and good adhesion to steel plate substrates. It is suitable for shipbuilding, aircraft, high-speed rail, marine engineering and other fields. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the embodiments of the present application. Obviously, the described embodiments are only some embodiments of the present application, and not all embodiments. The technical features designed in the different embodiments of the present invention described below can be combined with each other as long as they do not conflict with each other. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0027] In the technical solution of this invention, all chemical reagents used are commercially available. Specifically, the hydroxyl acrylic resin was purchased from Jining Tangyi Chemical Co., Ltd. (model 9080); the waterborne polyurethane emulsion was purchased from Jining Fangyu Chemical Co., Ltd. (model 2099); titanium dioxide CAS number 1317-80-2; zinc oxide CAS number 1314-13-2; talc CAS number 14807-96-6; isocyanate-based propyltriethoxysilane CAS number 24801-88-5; 3-isocyanate-based propyltrimethoxysilane CAS number 15396-00-6; hexamethylene diisocyanate trimer CAS number 3779-63-3; and carboxymethyl chitosan CAS number 83512-85-0 (viscosity-average molecular weight 5.0 × 10⁻⁶). 3 (Deacetylation degree of 90%, carboxymethylation of 80%); sodium montmorillonite was purchased from Shanghai Jiadeer Chemical Technology Co., Ltd.; 5-chlorobenzotriazole CAS No. 94-97-3; triphenylphosphine CAS No. 603-35-0; (1,3-dichloropropyl)benzene CAS No. 14155-36-3; triethylamine CAS No. 121-44-8; acetone CAS No. 67-64-1; ethanol CAS No. 64-17-5; N,N-dimethylformamide CAS No. 68-12-2.

[0028] Example 1

[0029] A self-drying acrylic enamel includes component A and component B. Component A includes the following components by weight: 60 parts hydroxyl acrylic resin; 20 parts waterborne polyurethane emulsion; 15 parts pigments and fillers; 10 parts montmorillonite composite; 5 parts coupling agent; 2 parts leveling agent; 1 part dispersant; 0.5 parts defoamer; and 50 parts deionized water. Component B includes the following components by weight: 20 parts curing agent; wherein the pigment and filler is titanium dioxide; the coupling agent is isocyanate-propyltriethoxysilane; the leveling agent is EFKA-3030; the dispersant is BYK-107; the defoamer is EFKA-2722; and the curing agent is hexamethylene diisocyanate trimer.

[0030] A method for preparing a self-drying acrylic enamel includes the following steps: First, hydroxyl acrylic resin and waterborne polyurethane emulsion are mixed evenly according to the weight ratio. Then, pigments, fillers, montmorillonite composite, coupling agent, and deionized water are added and stirred for 40 minutes. Finally, leveling agent, dispersant, and defoamer are added and stirred for 10 minutes to obtain component A. Component B curing agent is added to component A and stirred for 20 minutes to obtain the acrylic enamel. The stirring speed is controlled within the range of 1000 r / min.

[0031] The preparation method of the montmorillonite complex is as follows: sodium montmorillonite is added to deionized water and stirred evenly. Modified carboxymethyl chitosan is added, and the mixture is stirred and reacted at 60°C for 5.5 h. After the reaction is completed, the mixture is precipitated with acetone, filtered, and the product is washed with acetone and dried to obtain the montmorillonite complex. The mass ratio of sodium montmorillonite to modified carboxymethyl chitosan is 1:1.

[0032] The preparation method of modified carboxymethyl chitosan is as follows: Carboxymethyl chitosan is added to the reaction solvent and stirred evenly. Triethylamine and a modifier are added, and the mixture is stirred and reacted at 65°C for 8 hours. After the reaction is completed, the pH of the reaction solution is adjusted to neutral, and precipitation is carried out with acetone. The product is then filtered, washed with acetone, and dried to obtain modified carboxymethyl chitosan. The degree of substitution of the modifier is determined to be 13.5% by elemental analysis. The modifier consists of 5-chlorobenzotriazole and quaternary phosphonium salt monomers in a mass ratio of 1:1. The mass ratio of carboxymethyl chitosan, modifier, and triethylamine is 1:0.4:0.15. The reaction solvent is a 60wt% ethanol solution. The amount of reaction solvent used is 25 times the mass of carboxymethyl chitosan.

[0033] The preparation method of the quaternary phosphonium salt monomer is as follows: 26.0 g of triphenylphosphine was added to 500 mL of N,N-dimethylformamide, stirred evenly, and under nitrogen protection, 20.6 g of (1,3-dichloropropyl)benzene was added at 120 °C. The reaction was then continued with stirring for 22 h. After the reaction was completed, the mixture was extracted with water and dichloromethane, the aqueous phase was collected, concentrated, and dried to obtain 36.2 g of quaternary phosphonium salt monomer. The molar ratio of triphenylphosphine to (1,3-dichloropropyl)benzene was 1:1.1. During the reaction, due to steric hindrance, the chlorine atoms in (1,3-dichloropropyl)benzene that are far from the benzene ring preferentially react with triphenylphosphine. Quaternary phosphonium salt monomer: ESI ( m / z): 451.1 [M+H]+, 1H-NMR (600MHz, DMSO-d6, δppm): 7.60 (d, J=8.6Hz, 2H), 7.35-7.37 (m, 9H), 7.29-7.33 (m, 9H), 4.66 (d, J=7.2Hz, 1H), 1.90-1.93 (m, 2H), 1.33-1.36 (m, 2H); The reaction process is as follows:

[0034] .

[0035] Example 2

[0036] A self-drying acrylic enamel includes component A and component B. Component A includes the following components by weight: 50 parts hydroxyl acrylic resin; 15 parts waterborne polyurethane emulsion; 12 parts pigments and fillers; 8 parts montmorillonite composite; 6 parts coupling agent; 1 part leveling agent; 0.8 parts dispersant; 0.3 parts defoamer; and 40 parts deionized water. Component B includes the following components by weight: 15 parts curing agent; wherein the pigment and filler is mica powder; the coupling agent is 3-isocyanate-propyltrimethoxysilane; the leveling agent is BYK-345; the dispersant is BYK-103; the defoamer is EFKA-2020; and the curing agent is hexamethylene diisocyanate trimer.

[0037] A method for preparing a self-drying acrylic enamel includes the following steps: First, hydroxyl acrylic resin and waterborne polyurethane emulsion are mixed evenly according to the weight ratio. Then, pigments, fillers, montmorillonite composite, coupling agent, and deionized water are added and stirred for 30 minutes. Finally, leveling agent, dispersant, and defoamer are added and stirred for 15 minutes to obtain component A. Component B curing agent is added to component A and stirred for 15 minutes to obtain the acrylic enamel. The stirring speed is controlled within the range of 1200 r / min.

[0038] The preparation method of the montmorillonite complex is as follows: sodium montmorillonite is added to deionized water and stirred evenly. Modified carboxymethyl chitosan is added and stirred at 50°C for 6 hours. After the reaction is completed, precipitation is carried out with acetone, filtered, and the product is washed with acetone and dried to obtain the montmorillonite complex. The mass ratio of sodium montmorillonite to modified carboxymethyl chitosan is 1:0.8.

[0039] The preparation method of modified carboxymethyl chitosan is as follows: Carboxymethyl chitosan is added to the reaction solvent and stirred evenly. Triethylamine and a modifier are added, and the mixture is stirred and reacted at 70°C for 6 hours. After the reaction is completed, the pH of the reaction solution is adjusted to neutral, and precipitation is carried out with acetone. The product is then filtered, washed with acetone, and dried to obtain modified carboxymethyl chitosan. The degree of substitution of the modifier is determined to be 12.1% by elemental analysis. The modifier consists of 5-chlorobenzotriazole and quaternary phosphonium salt monomers in a mass ratio of 1:1. The mass ratio of carboxymethyl chitosan, modifier, and triethylamine is 1:0.3:0.1. The reaction solvent is a 50wt% ethanol solution. The amount of reaction solvent used is 25 times the mass of carboxymethyl chitosan.

[0040] Example 3

[0041] A self-drying acrylic enamel includes component A and component B. Component A includes the following components by weight: 55 parts hydroxyl acrylic resin; 17 parts waterborne polyurethane emulsion; 10 parts pigments and fillers; 9 parts montmorillonite composite; 4 parts coupling agent; 1.5 parts leveling agent; 0.5 parts dispersant; 0.4 parts defoamer; and 45 parts deionized water. Component B includes the following components by weight: 18 parts curing agent; wherein the pigment and filler is talc; the coupling agent is isocyanate-propyltriethoxysilane; the leveling agent is BYK-323; the dispersant is BYK-106; the defoamer is BYK-1794; and the curing agent is hexamethylene diisocyanate trimer.

[0042] A method for preparing a self-drying acrylic enamel includes the following steps: First, hydroxyl acrylic resin and waterborne polyurethane emulsion are mixed evenly according to the weight ratio. Then, pigments, fillers, montmorillonite composite, coupling agent, and deionized water are added and stirred for 35 minutes. Finally, leveling agent, dispersant, and defoamer are added and stirred for 12 minutes to obtain component A. Component B curing agent is added to component A and stirred for 16 minutes to obtain the acrylic enamel. The stirring speed is controlled within the range of 1100 r / min.

[0043] The preparation method of the montmorillonite complex is as follows: sodium montmorillonite is added to deionized water and stirred evenly. Modified carboxymethyl chitosan is added, and the mixture is stirred and reacted at 55°C for 5 hours. After the reaction is completed, the mixture is precipitated with acetone, filtered, and the product is washed with acetone and dried to obtain the montmorillonite complex. The mass ratio of sodium montmorillonite to modified carboxymethyl chitosan is 1:0.9.

[0044] The preparation method of modified carboxymethyl chitosan is as follows: Carboxymethyl chitosan is added to the reaction solvent and stirred evenly. Triethylamine and a modifier are added, and the mixture is stirred and reacted at 60°C for 7 hours. After the reaction is completed, the pH of the reaction solution is adjusted to neutral, and precipitation is carried out with acetone. The product is then filtered, washed with acetone, and dried to obtain modified carboxymethyl chitosan. The degree of substitution of the modifier is determined to be 12.8% by elemental analysis. The modifier consists of 5-chlorobenzotriazole and quaternary phosphonium salt monomers in a mass ratio of 1:1. The mass ratio of carboxymethyl chitosan, modifier, and triethylamine is 1:0.35:0.12. The reaction solvent is a 55wt% ethanol solution. The amount of reaction solvent used is 25 times the mass of carboxymethyl chitosan.

[0045] Example 4

[0046] A self-drying acrylic enamel includes component A and component B. Component A includes the following components by weight: 60 parts hydroxyl acrylic resin; 18 parts waterborne polyurethane emulsion; 14 parts pigments and fillers; 10 parts montmorillonite composite; 4 parts coupling agent; 1 part leveling agent; 0.8 parts dispersant; 0.5 parts defoamer; and 40 parts deionized water. Component B includes the following components by weight: 16 parts curing agent; wherein the pigment and filler is zinc oxide; the coupling agent is 3-isocyanate-propyltrimethoxysilane; the leveling agent is BYK-323; the dispersant is BYK-103; the defoamer is EFKA-2722; and the curing agent is hexamethylene diisocyanate trimer.

[0047] A method for preparing a self-drying acrylic enamel includes the following steps: First, hydroxyl acrylic resin and waterborne polyurethane emulsion are mixed evenly according to the weight ratio. Then, pigments, fillers, montmorillonite composite, coupling agent, and deionized water are added and stirred for 40 minutes. Finally, leveling agent, dispersant, and defoamer are added and stirred for 10 minutes to obtain component A. Component B curing agent is added to component A and stirred for 18 minutes to obtain the acrylic enamel. The stirring speed is controlled within the range of 1200 r / min.

[0048] The preparation method of the montmorillonite complex is as follows: sodium montmorillonite is added to deionized water and stirred evenly. Modified carboxymethyl chitosan is added, and the mixture is stirred and reacted at 60°C for 6 hours. After the reaction is completed, the mixture is precipitated with acetone, filtered, and the product is washed with acetone and dried to obtain the montmorillonite complex. The mass ratio of sodium montmorillonite to modified carboxymethyl chitosan is 1:0.9.

[0049] The preparation method of modified carboxymethyl chitosan is as follows: Carboxymethyl chitosan is added to the reaction solvent and stirred evenly. Triethylamine and a modifier are added, and the mixture is stirred and reacted at 70°C for 7 hours. After the reaction is completed, the pH of the reaction solution is adjusted to neutral, and precipitation is carried out with acetone. The product is then filtered, washed with acetone, and dried to obtain modified carboxymethyl chitosan. The degree of substitution of the modifier is determined to be 13.3% by elemental analysis. The modifier consists of 5-chlorobenzotriazole and quaternary phosphonium salt monomers in a mass ratio of 1:1. The mass ratio of carboxymethyl chitosan, modifier, and triethylamine is 1:0.4:0.14. The reaction solvent is a 55wt% ethanol solution. The amount of reaction solvent used is 25 times the mass of carboxymethyl chitosan.

[0050] Comparative Example 1

[0051] Compared with Example 1, the components of the acrylic enamel in this comparative example are different.

[0052] A self-drying acrylic enamel includes component A and component B. Component A includes the following components by weight: 60 parts hydroxyl acrylic resin; 20 parts waterborne polyurethane emulsion; 15 parts pigments and fillers; 10 parts montmorillonite composite; 5 parts coupling agent; 2 parts leveling agent; 1 part dispersant; 0.5 parts defoamer; and 50 parts deionized water. Component B includes the following components by weight: 20 parts curing agent; wherein the pigment and filler is titanium dioxide; the coupling agent is isocyanate-propyltriethoxysilane; the leveling agent is EFKA-3030; the dispersant is BYK-107; the defoamer is EFKA-2722; and the curing agent is hexamethylene diisocyanate trimer.

[0053] The preparation method of a self-drying acrylic enamel is the same as that in Example 1.

[0054] The montmorillonite complex is composed of sodium montmorillonite and carboxymethyl chitosan in a mass ratio of 1:1.

[0055] Comparative Example 2

[0056] A self-drying acrylic enamel includes component A and component B. Component A includes the following components by weight: 60 parts hydroxyl acrylic resin; 20 parts waterborne polyurethane emulsion; 15 parts pigments and fillers; 10 parts sodium montmorillonite; 5 parts coupling agent; 2 parts leveling agent; 1 part dispersant; 0.5 parts defoamer; and 50 parts deionized water. Component B includes the following components by weight: 20 parts curing agent; wherein the pigment and filler is titanium dioxide; the coupling agent is isocyanate-propyltriethoxysilane; the leveling agent is EFKA-3030; the dispersant is BYK-107; the defoamer is EFKA-2722; and the curing agent is hexamethylene diisocyanate trimer.

[0057] The preparation method of a self-drying acrylic enamel is the same as that in Example 1.

[0058] Comparative Example 3

[0059] Compared with Example 1, the components of the acrylic enamel in this comparative example are different.

[0060] A self-drying acrylic enamel includes component A and component B. Component A includes the following components by weight: 60 parts hydroxyl acrylic resin; 20 parts waterborne polyurethane emulsion; 15 parts pigments and fillers; 5 parts coupling agent; 2 parts leveling agent; 1 part dispersant; 0.5 parts defoamer; and 50 parts deionized water. Component B includes the following components by weight: 20 parts curing agent; wherein the pigment and filler is titanium dioxide; the coupling agent is isocyanate-propyltriethoxysilane; the leveling agent is EFKA-3030; the dispersant is BYK-107; the defoamer is EFKA-2722; and the curing agent is hexamethylene diisocyanate trimer.

[0061] The preparation method of a self-drying acrylic enamel is the same as that in Example 1.

[0062] Test case

[0063] The performance of the acrylic enamels prepared in Examples 1 to 4 and Comparative Examples 1 to 3 was tested according to HG / T 4758-2014 standard, with a cross-cut test spacing of 1 mm (steel plate), a salt spray resistance time of 120 h, and an artificial aging resistance time of 500 h. The antibacterial properties of the acrylic enamels were tested according to HG / T3950-2007 standard. The test results are shown in Table 1 below. Table 1

[0064] As shown in Table 1, the acrylic enamels prepared in Examples 1 to 4 of this invention have a fast drying speed and good hardness, impact resistance, corrosion resistance, aging resistance, and antibacterial properties, as well as good adhesion to steel substrates. By comparing Comparative Examples 1 to 3 with Example 1, it can be found that the montmorillonite composite in the acrylic enamel component of Example 1 of this invention can improve the suspension stability of the acrylic enamel. The uniformly dispersed montmorillonite flakes can effectively fill the micropores of the paint film, improve the density of the paint film, and can also work with carboxymethyl chitosan molecular chains to increase the crosslinking density of the paint film, thereby helping to improve the corrosion resistance of the acrylic enamel. In particular, the carboxymethyl chitosan molecules and quaternary phosphonium salt groups in the montmorillonite composite can significantly improve the antibacterial properties of the acrylic enamel, and the benzimidazole groups can improve the aging resistance of the acrylic enamel. The multiple rigid benzene ring structures in the quaternary phosphonium salt groups can also be dispersed in the paint film during the crosslinking process, improving the hardness and impact resistance of the acrylic enamel.

[0065] It should be noted that, in this document, terms such as "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Although embodiments of this application have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations can be made to these embodiments without departing from the principles and spirit of this application, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A self-drying acrylic enamel, characterized in that, The product comprises component A and component B. Component A comprises the following components by weight: 50-60 parts hydroxyl acrylic resin; 15-20 parts waterborne polyurethane emulsion; 10-15 parts pigments and fillers; 8-10 parts montmorillonite composite; 4-6 parts coupling agent; 1-2 parts leveling agent; 0.5-1 part dispersant; 0.3-0.5 parts defoamer; and 40-50 parts deionized water. Component B comprises the following components by weight: 15-20 parts curing agent. The preparation method of the montmorillonite complex is as follows: sodium montmorillonite is added to deionized water and stirred evenly. Modified carboxymethyl chitosan is added, and the mixture is stirred and reacted at 50-60℃ for 5-6 hours to obtain the montmorillonite complex. The modified carboxymethyl chitosan is prepared as follows: carboxymethyl chitosan is added to a reaction solvent and stirred until homogeneous. Triethylamine and a modifier are then added, and the mixture is stirred and reacted at 60-70°C for 6-8 hours to obtain modified carboxymethyl chitosan. The modifier is composed of 5-chlorobenzotriazole and quaternary phosphonium salt monomers in a mass ratio of 1:

1. The mass ratio of carboxymethyl chitosan, modifier, and triethylamine is 1:0.3-0.4:0.1-0.

15. The reaction solvent is a 50-60 wt% ethanol solution. The method for preparing the quaternary phosphonium salt monomer is as follows: triphenylphosphine is added to N,N-dimethylformamide, stirred evenly, and under nitrogen protection, (1,3-dichloropropyl)benzene is added at 115-120℃, and then the reaction is continued to be stirred for 22-24h to obtain the antibacterial quaternary phosphonium salt; the molar ratio of triphenylphosphine to (1,3-dichloropropyl)benzene is 1:1.1-1.

2.

2. The self-drying acrylic enamel paint according to claim 1, characterized in that, In the preparation method of the montmorillonite complex, the mass ratio of sodium-based montmorillonite to modified carboxymethyl chitosan is 1:0.8-1.

3. The self-drying acrylic enamel paint according to claim 1, characterized in that, The pigments and fillers are any one or a mixture of several of titanium dioxide, zinc oxide, mica powder, and talc powder; the coupling agent is isocyanate-propyltriethoxysilane or 3-isocyanate-propyltrimethoxysilane.

4. The self-drying acrylic enamel paint according to claim 1, characterized in that, The leveling agent is any one or a mixture of several of EFKA-3030, BYK-345, and BYK-323; the dispersant is any one or a mixture of several of BYK-103, BYK-106, and BYK-107; and the defoamer is any one or a mixture of several of EFKA-2020, EFKA-2722, and BYK-1794.

5. The self-drying acrylic enamel paint according to claim 1, characterized in that, The curing agent is hexamethylene diisocyanate trimer.

6. A method for preparing a self-drying acrylic enamel paint as described in any one of claims 1-5, characterized in that, The process includes the following steps: First, mix the hydroxyl acrylic resin and waterborne polyurethane emulsion evenly according to the weight ratio. Then, add pigments, fillers, montmorillonite complex, coupling agent, and deionized water, and stir for 30-40 minutes. Finally, add leveling agent, dispersant, and defoamer, and stir for 10-15 minutes to obtain component A. Add component B curing agent to component A and stir for 15-20 minutes to obtain acrylic enamel.

7. The method for preparing a self-drying acrylic enamel according to claim 6, characterized in that, During the preparation of acrylic enamel, the stirring speed is controlled within the range of 1000-1200 r / min.

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