A kind of water-based acrylic paint and preparation thereof

Abstract

The present invention belongs to the technical field of coatings, and specifically relates to a water-based acrylic coating and its preparation. In the present invention, hydroxyethyl acrylate containing hydroxyl groups and methacrylic acid containing carboxyl groups are selected as main monomers, which are polymerized with styrene and cyclohexyl methacrylate to form a water-based acrylic resin, which is combined with a dispersant, a thickener, an adhesion promoter, a film-forming aid, a filler, sodium dodecyl sulfate and water to form a water-based acrylic coating. In the present invention, the water resistance and weather resistance of the water-based acrylic coating are effectively improved by adjusting the formula of the water-based acrylic resin and the film-forming aid, and hydroxyl groups and carboxyl groups are introduced into the molecular structure of the water-based acrylic resin, and fillers with nano-particle size are added, which effectively improves the adhesion between the coating film and the substrate.

Description

Technical Field

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

[0002] Environmentally friendly coatings have always been one of the development trends in the coatings industry. Water-based acrylic emulsions use water as the main solvent and have a low VOC (volatile organic compound) content. They have good stain resistance, scrub resistance, light resistance, and acid and alkali resistance. They are widely used in furniture, construction, automobiles, aviation, electronics, packaging and other industries, and their market share is increasing.

[0003] Among them, the automobile manufacturing field is the main application field of water-based acrylic coatings. However, with the development of the automobile industry, the requirements for materials used in automobiles are becoming more and more stringent. The automobile body is exposed to the outside in a large area and directly contacts the atmospheric environment. This requires the coating of the automobile body to have good weather resistance and corrosion resistance so that the automobile can be used in various climate environments. However, the existing water-based acrylic coatings have poor adhesion to the substrate and cannot meet very high requirements. In addition, there are problems of insufficient water resistance and weather resistance. Therefore, it is of great significance to provide a water-based acrylic coating with good adhesion, water resistance and weather resistance.

[0004] The Chinese patent application document with publication number CN118027768A discloses a water-based acrylic paint, which is prepared from the following raw materials: 40-60 parts of water-based acrylic resin, 5-8 parts of polydimethylsiloxane, 6-10 parts of nano titanium dioxide, 2-4 parts of HEC hydroxyethyl cellulose, 8-10 parts of dispersant, 10-15 parts of filler, 1-3 parts of preservative and 30-50 parts of deionized water. This invention uses water-based acrylic resin as the base material, and selectively adds polydimethylsiloxane and nano titanium dioxide and other ingredients. The water-based acrylic paint has good salt spray resistance, fire resistance and adhesion, and can improve the salt spray resistance and flame retardancy of the water-based acrylic paint, but its weather resistance is not improved.

[0005] A Chinese patent document with publication number CN115785781A discloses a two-component water-based hydroxylated acrylic coating, including a dispersion component and a curing agent component, wherein the dispersion component contains two dispersions: a first hydroxylated acrylic dispersion and a second hydroxylated acrylic dispersion; wherein the hydroxyl value of the first hydroxylated acrylic dispersion is 3.9 mgKOH / g, and the hydroxyl value of the second hydroxylated acrylic dispersion is 4.2 mgKOH / g. This acrylic coating is a two-component water-based coating with acid and alkali corrosion resistance far superior to similar products by adapting two hydroxylated acrylic dispersions with different hydroxyl values, but its water resistance is poor. Summary of the invention

[0006] In order to solve the technical problem that the adhesion, water resistance and weather resistance of the related art water-based acrylic paint cannot be achieved at the same time, the present invention provides a water-based acrylic paint and its preparation method.

[0007] In order to achieve the above object, the technical solution of the present invention is as follows:

[0008] A water-based acrylic paint comprises the following components and their weight proportions:

[0009] 50-60 parts of water-based acrylic resin, 5-8 parts of dispersant, 10-15 parts of thickener, 5-10 parts of adhesion promoter, 3-5 parts of film-forming aid, 12-16 parts of filler, 5-8 parts of sodium lauryl sulfate, 70-80 parts of water;

[0010] The preparation method of the water-based acrylic resin is as follows: 30-40 parts of ethanol aqueous solution, 5-8 parts of hydrogen peroxide and 1-3 parts of mercaptopropionic acid are added into a reaction kettle, the temperature is raised to 70-80° C. under stirring, 40-55 parts of a mixture of hydroxyethyl acrylate, methacrylic acid, styrene and cyclohexyl methacrylate are added dropwise, the addition is completed within 3 hours, after the addition is completed, the reaction is kept warm for 2-2.5 hours, and the reaction is cooled to obtain the water-based acrylic resin.

[0011] The hydrophobicity of the monomer determines the hydrophobicity of the acrylic resin, thereby affecting the water resistance of the water-based acrylic coating. The present invention adds styrene to the formula of the water-based acrylic resin to improve the hydrophobicity of the water-based acrylic resin. However, studies have found that the addition of styrene will cause the weather resistance of the water-based acrylic resin to deteriorate and become yellowish. Therefore, the inventors continue to add cyclohexyl methacrylate to the water-based acrylic resin formula. Due to its large side chain volume, large number of carbon atoms, and poor hygroscopicity, it can effectively improve the weather resistance of the water-based acrylic resin while also improving the water resistance.

[0012] In addition, in the present invention, hydroxyethyl acrylate containing a hydroxyl group and methacrylic acid containing a carboxyl group are selected as main monomers, which are polymerized with styrene and cyclohexyl methacrylate to form a water-based acrylic resin. The hydroxyl group and carboxyl group contained in the molecular structure of the water-based acrylic resin can combine with the substrate to form a chemical bond, which can significantly improve the adhesion of the water-based acrylic resin to the substrate, and the greater the density of the hydroxyl group and the carboxyl group, the higher the adhesion.

[0013] Furthermore, in the preparation method of the water-based acrylic resin, the volume fraction of the ethanol aqueous solution is 60-65%.

[0014] Furthermore, in the preparation method of the water-based acrylic resin, the mixing mass ratio of hydroxyethyl acrylate, methacrylic acid, styrene and cyclohexyl methacrylate is 11-14:17-20:3-5:4-7.

[0015] In the present invention, the hydrophobicity of the waterborne acrylic resin and the number of polar groups in the molecule are controlled by adjusting the mixing mass ratio of hydroxyethyl acrylate, methacrylic acid, styrene and cyclohexyl methacrylate, thereby controlling the water resistance and adhesion of the waterborne acrylic coating.

[0016] Furthermore, the dispersant in the water-based acrylic paint is one of sodium oleate, sodium acetate and sodium dodecyl sulfate.

[0017] Furthermore, the thickener in the water-based acrylic paint is composed of hydroxyethyl cellulose and sodium polyacrylate in a mass ratio of 7-9:2-4.

[0018] Furthermore, the adhesion promoter in the waterborne acrylic coating is vinyltriethoxysilane, vinyltrimethoxysilane or isobutyltriethoxysilane.

[0019] Furthermore, the film-forming aid in the water-based acrylic paint is composed of ethylene glycol butyl ether and polyvinyl pyrrolidone in a mass ratio of 12-15:5-8.

[0020] In the present invention, a film-forming aid is added to the water-based acrylic paint, which can not only reduce the film-forming temperature but also improve the film-forming performance of the paint. However, it is found in the research process that after adding butyl glycol, the early water resistance of the paint will deteriorate, which is caused by the good hydrophilicity of butyl glycol and the slow drying of the paint. The addition of polyvinyl pyrrolidone can alleviate the deterioration of the early water resistance. When butyl glycol and polyvinyl pyrrolidone are composed according to the mass ratio of 12-15:5-8, the early water resistance and final water resistance of the paint are both optimal.

[0021] Furthermore, the filler in the water-based acrylic paint is one of barium sulfate, silicon dioxide and mica powder, and the particle size of the filler is 230-260 nm.

[0022] In the present invention, fillers with nanometer particle size are selected. Nanoparticles have a large specific surface area. After the coating is formed, the nanoparticles make the surface of the paint film rough, thereby increasing the contact area between the paint film and the substrate, and effectively improving the adhesion between the paint coating and the substrate. However, nanoparticles can increase the hydrophilicity of the paint film, so it is necessary to strictly control the amount of nanofillers to avoid the poor water resistance of the paint film due to the large amount of nanoparticles.

[0023] The present invention also provides a method for preparing the water-based acrylic paint, comprising the following steps:

[0024] S1, mixing water-based acrylic resin, thickener and sodium lauryl sulfate, adding water, stirring for 20-30 minutes, and obtaining emulsion I;

[0025] S2. Add the dispersant and the film-forming aid to the emulsion I obtained in step S1, stir evenly, then add the filler, continue stirring for 10-20 minutes, add the adhesion promoter, stir evenly, and obtain the product.

[0026] Compared with the prior art, the water-based acrylic paint and the preparation method thereof provided by the present invention have the following technical advantages:

[0027] In the present invention, styrene and cyclohexyl methacrylate are added to the formula of water-based acrylic resin, and ethylene glycol butyl ether and polyvinyl pyrrolidone are selected as film-forming aids, which effectively improve the water resistance of water-based acrylic coatings; hydroxyethyl acrylate, methacrylic acid, styrene and cyclohexyl methacrylate are selected as copolymer monomers of water-based acrylic resin, which effectively improves the weather resistance of water-based acrylic coatings; (2) In the present invention, hydroxyethyl acrylate containing hydroxyl groups and methacrylic acid containing carboxyl groups are selected as main monomers, hydroxyl groups and carboxyl groups are introduced into the molecular structure of water-based acrylic resin, and fillers with nano-particle size are added, which effectively improves the adhesion between the coating film and the substrate;

[0028] (3) The water-based acrylic paint provided by the present invention has a simple formula, readily available raw materials, and a preparation process that does not require complicated operations, which is conducive to industrial production. DETAILED DESCRIPTION

[0029] The present invention will be further described below in conjunction with specific embodiments, but the present invention is not limited to the following embodiments. Those skilled in the art can make various modifications based on the basic idea of ​​the present invention, but as long as they do not deviate from the basic idea of ​​the present invention, they are all within the scope of the present invention.

[0030] Example 1

[0031] A water-based acrylic paint comprises the following components and their weight proportions:

[0032] 50 parts of water-based acrylic resin, 8 parts of sodium oleate, 10 parts of thickener, 10 parts of vinyl triethoxysilane, 3 parts of film-forming aid, 16 parts of barium sulfate, 5 parts of sodium lauryl sulfate, 80 parts of water;

[0033] The preparation method of the water-based acrylic resin is as follows: 30 parts of 60% ethanol aqueous solution by volume, 5 parts of hydrogen peroxide and 1 part of mercaptopropionic acid are added into a reaction kettle, the temperature is raised to 70° C. under stirring, 40 parts of a mixture of hydroxyethyl acrylate, methacrylic acid, styrene and cyclohexyl methacrylate are added dropwise, the addition is completed within 3 hours, the mixing mass ratio of hydroxyethyl acrylate, methacrylic acid, styrene and cyclohexyl methacrylate is 11:17:3:4, after the addition is completed, the reaction is kept warm for 2 hours, and the mixture is cooled to obtain the water-based acrylic resin.

[0034] The thickener is composed of hydroxyethyl cellulose and sodium polyacrylate in a mass ratio of 7:2; the film-forming aid is composed of ethylene glycol butyl ether and polyvinyl pyrrolidone in a mass ratio of 12:5; and the particle size of the filler is 230 nm.

[0035] The present invention also provides a method for preparing the water-based acrylic paint, comprising the following steps: S1, mixing a water-based acrylic resin, a thickener and sodium lauryl sulfate, adding water, and stirring for 20 minutes to obtain an emulsion I; S2, adding a dispersant and a film-forming aid to the emulsion I obtained in step S1, stirring evenly, adding a filler, continuing to stir for 10 minutes, adding an adhesion promoter, and stirring evenly to obtain the paint.

[0036] Example 2

[0037] A water-based acrylic paint comprises the following components and their weight proportions:

[0038] 56 parts of water-based acrylic resin, 7 parts of sodium acetate, 12 parts of thickener, 8 parts of vinyl trimethoxy silane, 4 parts of film-forming aid, 15 parts of silicon dioxide, 7 parts of sodium lauryl sulfate, and 78 parts of water;

[0039] The preparation method of the water-based acrylic resin is as follows: 35 parts of 62% ethanol aqueous solution by volume, 7 parts of hydrogen peroxide and 2 parts of mercaptopropionic acid are added into a reaction kettle, the temperature is raised to 75° C. under stirring, 43 parts of a mixture of hydroxyethyl acrylate, methacrylic acid, styrene and cyclohexyl methacrylate are added dropwise, the addition is completed within 3 hours, the mass ratio of hydroxyethyl acrylate, methacrylic acid, styrene and cyclohexyl methacrylate is 13:18:4:6, after the addition is completed, the reaction is kept warm for 2.2 hours, and the mixture is cooled to obtain the water-based acrylic resin.

[0040] The thickener is composed of hydroxyethyl cellulose and sodium polyacrylate in a mass ratio of 8:3; the film-forming aid is composed of ethylene glycol butyl ether and polyvinyl pyrrolidone in a mass ratio of 13:7; and the particle size of the filler is 250 nm.

[0041] The present invention also provides a method for preparing the water-based acrylic paint, comprising the following steps: S1, mixing a water-based acrylic resin, a thickener and sodium lauryl sulfate, adding water, and stirring for 25 minutes to obtain an emulsion I; S2, adding a dispersant and a film-forming aid to the emulsion I obtained in step S1, stirring evenly, adding a filler, continuing to stir for 15 minutes, adding an adhesion promoter, and stirring evenly to obtain the paint.

[0042] Example 3

[0043] A water-based acrylic paint comprises the following components and their weight proportions:

[0044] 60 parts of water-based acrylic resin, 5 parts of sodium dodecyl sulfate, 15 parts of thickener, 5 parts of isobutyl triethoxy silane, 5 parts of film-forming aid, 12 parts of mica powder, 8 parts of sodium dodecyl sulfate, and 70 parts of water;

[0045] The preparation method of the water-based acrylic resin is as follows: 40 parts of 65% ethanol aqueous solution by volume, 8 parts of hydrogen peroxide and 3 parts of mercaptopropionic acid are added into a reaction kettle, the temperature is raised to 80° C. under stirring, 55 parts of a mixture of hydroxyethyl acrylate, methacrylic acid, styrene and cyclohexyl methacrylate are added dropwise, the addition is completed within 3 hours, the mass ratio of hydroxyethyl acrylate, methacrylic acid, styrene and cyclohexyl methacrylate is 14:20:5:7, after the addition is completed, the reaction is kept warm for 2.5 hours, and the mixture is cooled to obtain the water-based acrylic resin.

[0046] The thickener is composed of hydroxyethyl cellulose and sodium polyacrylate in a mass ratio of 9:4; the film-forming aid is composed of ethylene glycol butyl ether and polyvinyl pyrrolidone in a mass ratio of 15:8; and the particle size of the filler is 260 nm.

[0047] The present invention also provides a method for preparing the water-based acrylic paint, comprising the following steps: S1, mixing a water-based acrylic resin, a thickener and sodium lauryl sulfate, adding water, and stirring for 30 minutes to obtain an emulsion I; S2, adding a dispersant and a film-forming aid to the emulsion I obtained in step S1, stirring evenly, adding a filler, continuing to stir for 20 minutes, adding an adhesion promoter, and stirring evenly to obtain the paint.

[0048] Comparative Example 1

[0049] The formula and preparation method of the coating in this comparative example are similar to those of Example 2. The difference between this comparative example and Example 2 is that an equal amount of acrylic acid is used instead of styrene in the preparation method of the water-based acrylic resin in this comparative example.

[0050] Comparative Example 2

[0051] The formula and preparation method of the coating described in this comparative example are similar to those of Example 2. The difference between this comparative example and Example 2 is that an equal amount of acrylic acid is used instead of cyclohexyl methacrylate in the preparation method of the water-based acrylic resin described in this comparative example.

[0052] Comparative Example 3

[0053] The formula and preparation method of the coating described in this comparative example are similar to those of Example 2. The difference between this comparative example and Example 2 is that an equal amount of acrylic acid is used instead of hydroxyethyl acrylate in the preparation method of the water-based acrylic resin described in this comparative example.

[0054] Comparative Example 4

[0055] The formula and preparation method of the coating described in this comparative example are similar to those of Example 2. The difference between this comparative example and Example 2 is that in the preparation method of the water-based acrylic resin in this comparative example, the mixing mass ratio of hydroxyethyl acrylate, methacrylic acid, styrene and cyclohexyl methacrylate is 4:3:16:12.

[0056] Comparative Example 5

[0057] The formula and preparation method of the coating described in this comparative example are similar to those of Example 2. The difference between this comparative example and Example 2 is that the film-forming aid described in this comparative example is composed of ethylene glycol butyl ether and polyvinyl pyrrolidone in a mass ratio of 7:13.

[0058] Comparative Example 6

[0059] The formula and preparation method of the coating in this comparative example are similar to those of Example 2. The difference between this comparative example and Example 2 is that the film-forming aids in this comparative example are all ethylene glycol butyl ether.

[0060] Comparative Example 7

[0061] The formula and preparation method of the coating in this comparative example are similar to those of Example 2. The difference between this comparative example and Example 2 is that the particle size of the filler in this comparative example is 50 μm.

[0062] Test Example 1: Water resistance test

[0063] Test samples: coatings prepared from Examples 1 to 3, Comparative Examples 1 to 2, and Comparative Examples 4 to 6;

[0064] Test method: Prepare the coating film on the cold-rolled steel plate according to GB / T 9271-2008 "Standard Test Plate for Paints and Varnishes", with a dry film thickness of about 50μm.

[0065] Early water resistance test: The sample is dried in a standard constant temperature and humidity room for 2 hours, and after the bottom and edges are sealed, it is placed in deionized water at room temperature, with about 2 / 3 of the sample immersed in water. The state of the coating is observed until the coating bubbles, wrinkles or the substrate rusts, and the time when the coating is damaged is recorded.

[0066] Final water resistance test: The sample is dried in a standard constant temperature and humidity room for 7 days, and after the bottom and edge are sealed, it is placed in deionized water at room temperature, with about 2 / 3 of the sample immersed in water. The coating state is observed until the coating bubbles, wrinkles or the substrate rusts, and the time when the coating is damaged is recorded.

[0067] Test results: The test results are shown in Table 1.

[0068] Table 1 Coating water resistance test results

[0069]

[0070] As can be seen from Table 1, the early water resistance time of the water-based acrylic paint film provided by the present invention is 90-103h, and the final water resistance time is 10-13 days, which has a good water resistance effect. Among them, the early water resistance time and the final water resistance time of the water-based acrylic paint film prepared in Example 2 are the longest, which is the best embodiment of the present invention.

[0071] Compared with Example 2, in Comparative Example 1, an equal amount of acrylic acid was used to replace styrene, but the water resistance of the coating film was deteriorated, indicating that the introduction of styrene into the water-based acrylic resin formula can improve its water resistance; in Comparative Example 2, an equal amount of acrylic acid was used to replace cyclohexyl methacrylate, and the water resistance of the coating film was slightly reduced, indicating that the introduction of cyclohexyl methacrylate into the water-based acrylic resin formula can improve its water resistance; in Comparative Example 4, the mixing mass ratio of hydroxyethyl acrylate, methacrylic acid, styrene and cyclohexyl methacrylate was changed, and the water resistance of the coating film was improved. The water content increased slightly, which indicates that the higher the content of styrene and cyclohexyl methacrylate in the water-based acrylic resin formula, the better the water resistance of the water-based acrylic resin; in Comparative Example 5, the film-forming aid is composed of ethylene glycol butyl ether and polyvinyl pyrrolidone in a mass ratio of 7:13, but the water resistance of the coating deteriorates, which indicates that the dosage ratio of the film-forming aid is the key to affecting the water resistance of the coating; in Comparative Example 6, the film-forming aid is all ethylene glycol butyl ether, but the early water resistance of the coating deteriorates, which indicates that ethylene glycol butyl ether will cause the early water resistance of the coating to deteriorate.

[0072] Test Example 2: Weathering Test

[0073] Test samples: coatings prepared in Examples 1 to 3, Comparative Examples 1 to 2, and Comparative Example 4;

[0074] Test method: According to GB / T 1865-2009 "Artificial weathering and artificial radiation exposure of paints and varnishes to filtered xenon lamp radiation", the coating's resistance to artificial weathering is tested. According to GB / T 1771-2007 "Determination of resistance of paints and varnishes to neutral salt spray", the coating's resistance to salt spray is tested, and the time when the coating film appears aging or corrosion is recorded respectively.

[0075] Test results: The test results are shown in Table 2.

[0076] Table 2 Test results of coating weather resistance

[0077]

[0078] As can be seen from Table 2, the coating film of the waterborne acrylic coating provided by the present invention has excellent artificial aging resistance and salt spray resistance, among which the waterborne acrylic coating prepared in Example 2 has the best artificial aging resistance and salt spray resistance.

[0079] Compared with Example 2, in Comparative Example 1, an equal amount of acrylic acid is used to replace styrene, but the artificial aging resistance and salt spray resistance of the prepared coating film are slightly increased, which indicates that the addition of styrene will cause the weather resistance of the water-based acrylic resin to deteriorate; in Comparative Example 2, an equal amount of acrylic acid is used to replace cyclohexyl methacrylate, but the artificial aging resistance and salt spray resistance of the prepared coating film are both deteriorated, which indicates that cyclohexyl methacrylate can improve the weather resistance of the water-based acrylic resin; in Comparative Example 4, the mixing mass ratio of hydroxyethyl acrylate, methacrylic acid, styrene and cyclohexyl methacrylate is changed, but the weather resistance of the prepared coating film is slightly reduced, which indicates that the usage ratio of hydroxyethyl acrylate, methacrylic acid, styrene and cyclohexyl methacrylate in the present invention has been optimized.

[0080] Test Example 3: Adhesion Test

[0081] Test samples: coatings prepared in Examples 1 to 3, Comparative Examples 1 to 4, and Comparative Example 7;

[0082] Test method: The adhesion grade of the test sample coating film is determined according to ASTM D3359-02 "Standard Test Method for Determining Adhesion by Tape Testing".

[0083] Test results: The test results are shown in Table 3.

[0084] Table 3 Coating adhesion test results

[0085]

[0086] It can be seen from Table 3 that the coating film of the water-based acrylic paint provided by the present invention has good bonding strength with the substrate.

[0087] Compared with Example 2, in Comparative Example 1, an equal amount of acrylic acid is used to replace styrene, and in Comparative Example 2, an equal amount of acrylic acid is used to replace cyclohexyl methacrylate. The adhesion of the coating film of the prepared coating does not change much, which indicates that in the water-based acrylic resin molecule, the number of hydroxyl and carboxyl groups is the key to adjusting the bonding force between the coating film and the substrate; in Comparative Example 3, an equal amount of acrylic acid is used to replace hydroxyethyl acrylate, but the adhesion of the coating film is slightly reduced, indicating that in the water-based acrylic resin, the adhesion when hydroxyl and carboxyl groups exist at the same time is better than the adhesion when carboxyl groups exist alone; in Comparative Example 4, the mixing mass ratio of hydroxyethyl acrylate, methacrylic acid, styrene and cyclohexyl methacrylate is changed, but the adhesion is poor, which indicates that the mixing mass ratio of hydroxyethyl acrylate, methacrylic acid, styrene and cyclohexyl methacrylate in the present invention has been optimized; in Comparative Example 7, the filler particle size is changed, but the adhesion is poor, which indicates that the nanofiller can increase the contact area between the paint film and the substrate after the coating film is formed, thereby improving the adhesion, while the micron-sized filler cannot achieve this technical effect.

[0088] The above embodiments are merely illustrative of the preparation method of the present invention, and are not intended to limit the present invention. Any person skilled in the art may not modify the above embodiments without violating the spirit and scope of the present invention. Therefore, all equivalent modifications or changes made by a person of ordinary skill in the art without departing from the technical concept provided by the present invention are still covered by the claims of the present invention.

Claims

1. A water-based acrylic paint, characterized in that: The composition comprises the following components in parts by weight: 50-60 parts of water-based acrylic resin, 5-8 parts of dispersant, 10-15 parts of thickener, 5-10 parts of adhesion promoter, 3-5 parts of film-forming aid, 12-16 parts of filler, 5-8 parts of sodium lauryl sulfate, 70-80 parts of water; The preparation method of the water-based acrylic resin is as follows: 30-40 parts of ethanol aqueous solution, 5-8 parts of hydrogen peroxide and 1-3 parts of mercaptopropionic acid are added to a reaction kettle, the temperature is raised to 70-80° C. under stirring, 40-55 parts of a mixture of hydroxyethyl acrylate, methacrylic acid, styrene and cyclohexyl methacrylate are added dropwise, the addition is completed within 3 hours, the temperature is kept for reaction for 2-2.5 hours after the addition is completed, and the water-based acrylic resin is cooled to obtain the resin; the mixing mass ratio of the hydroxyethyl acrylate, methacrylic acid, styrene and cyclohexyl methacrylate is 11-14:17-20:3-5:4-7; The film-forming aid is composed of ethylene glycol butyl ether and polyvinyl pyrrolidone in a mass ratio of 12-15:5-8; the filler is one of barium sulfate, silicon dioxide and mica powder, and the particle size of the filler is 230-260nm.

2. The water-based acrylic paint according to claim 1, characterized in that: The volume fraction of the ethanol aqueous solution in the preparation method of the water-based acrylic resin is 60-65%.

3. The water-based acrylic paint according to claim 1, characterized in that: The dispersant is one of sodium oleate, sodium acetate and sodium dodecyl sulfate.

4. The water-based acrylic paint according to claim 1, characterized in that: The thickener is composed of hydroxyethyl cellulose and sodium polyacrylate in a mass ratio of 7-9:2-4.

5. The water-based acrylic paint according to claim 1, characterized in that: The adhesion promoter is vinyl triethoxysilane, vinyl trimethoxysilane or isobutyl triethoxysilane.

6. The method for preparing a water-based acrylic paint according to any one of claims 1 to 5, characterized in that: The following steps are involved: S1, mixing water-based acrylic resin, thickener and sodium lauryl sulfate, adding water, stirring for 20-30 minutes, and obtaining emulsion I; S2, adding the dispersant and the film-forming aid to the emulsion I prepared in step S1, stirring evenly, adding the filler, continuing to stir for 10-20 minutes, adding the adhesion promoter, stirring evenly, and obtaining.

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