Acrylic resin coating with self-cleaning function

Abstract

The invention relates to the field of acrylic resin coatings, in particular to an acrylic resin coating with a self-cleaning function and a preparation method of the acrylic resin coating. Comprising the following raw materials in parts by weight: 40-60 parts of modified acrylic resin emulsion, 3-6 parts of a functional additive, 2-5 parts of a curing agent, 1.5-3 parts of a coalescing agent, 1-3 parts of a defoaming agent, 0.2-0.5 part of a flatting agent, 30-55 parts of deionized water and 1-1.5 parts of a dispersing agent, the self-cleaning functional monomer contains a fluorine-containing group and a benzene ring at the same time, so that the coating has excellent self-cleaning function and super-hydrophobic performance, and the benzene ring can also cooperate with a maleimide benzene structure in the functional additive and the inorganic nano-material to improve the heat resistance of the coating. And further application of the acrylic resin coating in the self-cleaning coating market is facilitated.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and particularly to an acrylic resin coating with self-cleaning function. Background Art

[0002] In recent years, with the continuous development of the economy, the construction and its supporting decoration industry have also simultaneously entered an unprecedented high-speed development era. As a common building decoration material, coatings have been more and more widely used in industry, agriculture, national defense, scientific research and people's lives. The varieties of coatings on the market are increasing day by day, the quality and performance are constantly improving, and many functional coating varieties gradually occupy a large market share. Among them, the coatings with self-cleaning function stand out among many functional coatings because they can reduce the cost of building exterior cleaning and improve the stain resistance of the coating.

[0003] For the development of self-cleaning function, the existing coatings mainly include three categories: hydrophobic, hydrophilic and photocatalytic. Most of the hydrophobic coatings form a "lotus leaf-like" biomimetic structure on the coating surface or use a single hydrophobic material to improve the hydrophobicity of the coating. The hydrophilic coatings mainly use the hydrophilic properties of the materials to remove the stains on the coating with water flow. The photocatalytic coatings mainly use the products generated after the materials absorb solar energy to photocatalytically degrade the pollutants. In addition, in order to solve the problems of easy powdering and yellowing of self-cleaning coatings in high-temperature environments, most coatings choose to add a single nano-inorganic material, but the self-cleaning performance persistence of the coating will also be affected due to the agglomeration problem of the nano-inorganic material itself.

[0004] Therefore, in view of the above-mentioned problems in the prior art, the present invention provides an acrylic resin coating with self-cleaning function, which can solve the problems existing in the prior art. Summary of the Invention

[0005] In order to solve the problems mentioned in the background art, the purpose of the present invention is to provide an acrylic resin coating with self-cleaning function and its preparation method.

[0006] The purpose of the present invention can be achieved by the following technical solutions:

[0007] An acrylic resin coating with self-cleaning function, by weight, comprises the following raw materials: 40-60 parts of modified acrylic resin emulsion, 3-6 parts of functional additive, 2-5 parts of curing agent, 1.5-3 parts of film-forming aid, 1-3 parts of defoaming agent, 0.2-0.5 part of leveling agent, 30-55 parts of deionized water, 1-1.5 parts of dispersant;

[0008] The modified acrylic resin emulsion comprises the following raw materials in parts by weight: 20 - 30 parts of methyl methacrylate, 10 - 15 parts of butyl acrylate, 3 - 5 parts of acrylic acid, 2 - 3 parts of emulsifier, 30 - 45 parts of deionized water, 2 - 3 parts of self - cleaning functional monomer, and 0.1 - 0.3 parts of initiator;

[0009] The preparation method of the modified acrylic resin emulsion comprises the following steps:

[0010] Step A1: Take 1 - 1.5 parts of emulsifier, 15 - 20 parts of methyl methacrylate, 4 - 6 parts of butyl acrylate, 1 - 2 parts of acrylic acid, and 15 - 20 parts of deionized water. Stir them together at 50 - 60 °C for 1 - 2 h to form acrylate pre - emulsion a;

[0011] Step A2: Mix 1 - 2 parts of sodium bicarbonate solution, 1 - 1.5 parts of emulsifier, 5 - 10 parts of methyl methacrylate, 6 - 9 parts of butyl acrylate, 2 - 3 parts of acrylic acid, and 15 - 25 parts of deionized water. Stir at 45 - 60 °C for 30 - 50 min, add 0.2 - 0.4 parts of initiator, raise the temperature to 70 - 80 °C, react for 1 - 2 h, then add the acrylate pre - emulsion a prepared in Step A1, 2 - 3 parts of self - cleaning functional monomer, and 0.3 - 0.6 parts of initiator. Stir for 15 - 30 min and react for 2 - 5 h to obtain the modified acrylic resin emulsion.

[0012] In the above technical solution, the unsaturated carbon - carbon double bonds contained in raw materials such as methyl methacrylate, acrylic acid, and butyl acrylate are initiated by the initiator persulfuric acid to generate free - radical polymerization reactions. At the same time, the fluorine - containing molecular long - chain grafting in the self - cleaning functional monomer can also be grafted onto the acrylic resin emulsion through the free - radical polymerization of the unsaturated carbon - carbon double bonds it possesses.

[0013] Further, the curing agent is ethylenediamine; the dispersant is polyvinylpyrrolidone or sodium polyacrylate.

[0014] Further, the leveling agent is an aqueous acrylate copolymer or polydimethylsiloxane; the defoaming agent is tributyl phosphate or fatty alcohol polyoxyethylene ether.

[0015] Further, the emulsifier is any one of OP - 10, sodium dodecylbenzenesulfonate, and sodium dodecylsulfonate.

[0016] Further, in Step A2, the initiator is an aqueous solution of 3 - 5 wt% sodium persulfate or an aqueous solution of 3 - 5 wt% potassium persulfate; the mass concentration of the sodium bicarbonate solution is 15 - 25%.

[0017] Further, the preparation method of the self - cleaning functional monomer comprises the following steps:

[0018] Dissolve 3,3-diphenylpropyl-2-propen-1-ol and perfluorohexylacetic acid in toluene, add p-toluenesulfonic acid, and under an anaerobic environment, react at 100-110 °C for 12-24 h. Then cool to room temperature, add potassium bicarbonate solution to adjust the pH to 7-8, filter and wash to obtain the self-cleaning functional monomer.

[0019] In the above technical solution, the hydroxyl group of 3,3-diphenylpropyl-2-propen-1-ol and the carboxylic acid group of perfluorohexylacetic acid undergo an esterification reaction under acidic conditions and catalysis by a catalyst, grafting the fluorinated long chain to the rigid structure containing a benzene ring through a chemical bond to obtain the self-cleaning functional monomer.

[0020] Further, the mass concentration of the potassium bicarbonate solution is 10-15%.

[0021] Further, the preparation method of the functional additive includes the following steps:

[0022] Disperse nano-zinc oxide in hydrogen peroxide solution, stir for 1-2 h, after centrifugation, filter and wash, and dry at 110-120 °C for 2-5 h. Then add the dried nano-zinc oxide to anhydrous N,N-dimethylformamide and stir for 30-50 min. Under an anaerobic environment, add 4-maleimidobenzoic acid, a catalyst, and dicyclohexylcarbodiimide, and react at a constant temperature of 40-60 °C under an anaerobic environment for 12-24 h. After the reaction, centrifuge, wash, and filter, and then dry in a vacuum environment at 60-80 °C for 12-24 h to obtain the functional additive.

[0023] In the above technical solution, after nano-zinc oxide is activated by hydrogen peroxide, the hydroxyl group it possesses and the carboxylic acid group in 4-maleimidobenzoic acid undergo an esterification reaction under the catalysis of 4-dimethylaminopyridine catalyst, grafting 4-maleimidophenyl onto nano-zinc oxide to obtain the functional additive.

[0024] Further, the catalyst is 4-dimethylaminopyridine or N-methylmorpholine.

[0025] A preparation method of an acrylic resin coating with self-cleaning function includes the following steps:

[0026] Step 1: Take deionized water, modified acrylic resin emulsion, film-forming aid, leveling agent, and dispersant by weight, and stir at a speed of 500-800 rpm for 20-30 min to form a mixed emulsion;

[0027] Step 2: Take defoamer, curing agent, functional additive and the mixed emulsion by weight, and stir at a speed of 800-1000 rpm for 10-25 min to obtain the acrylic resin coating.

[0028] The beneficial effects of the present invention:

[0029] (1) The present invention prepares a self-cleaning functional monomer to participate in the preparation of an acrylic resin emulsion, modifies the functional monomer containing a fluorine group, which can be free to the coating surface in the coating. By utilizing the strong hydrophobicity of the fluorine group and the benzene ring, a superhydrophobic surface is formed on the coating surface, making the coating surface not easily contaminated by water stains and stains. At the same time, the functional monomer also contains rigid structures such as benzene rings, which can improve the heat resistance of the coating, avoid the yellowing and powdering of the coating, and is beneficial to the long-term maintenance of the self-cleaning function of the coating in a high-temperature environment.

[0030] (2) The present invention prepares a nano-zinc oxide material containing a maleimide structure as a functional additive for the coating. The maleimide-based benzene structure can improve the uniform dispersion performance of nano-zinc oxide in the coating, and at the same time can also improve the heat resistance of the coating. Nano-zinc oxide itself has high thermal stability and is not easily decomposed at high temperatures, and can cooperate with maleimide to enhance the heat resistance of the coating, preventing the discoloration and powdering of the coating in a high-temperature environment.

[0031] Of course, it is not necessary for any product implementing the present invention to achieve all the above-mentioned advantages simultaneously. Description of the Drawings

[0032] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following will briefly introduce the drawings required for the description of the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0033] Figure 1 It is an infrared test chart of the self-cleaning functional monomer prepared in Example 1 of the present invention. Detailed Embodiments

[0034] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0035] Example 1: A self-cleaning acrylic resin coating, by weight, includes the following raw materials: 40 parts of modified acrylic resin emulsion, 6 parts of functional additive, 2 parts of curing agent ethylenediamine, 1.5 parts of film-forming aid, 1 part of defoaming agent tributyl phosphate, 0.2 part of leveling agent polydimethylsiloxane, 30 parts of deionized water, and 1 part of dispersant sodium polyacrylate.

[0036] The preparation method of the coating includes the following steps:

[0037] Step 1: Take deionized water, modified acrylic resin emulsion, film-forming aid, leveling agent polydimethylsiloxane, and dispersant sodium polyacrylate in parts by weight, and stir at a speed of 500 rpm for 20 min to form a mixed emulsion;

[0038] Step 2: Take defoamer tributyl phosphate, curing agent ethylenediamine, functional additive and the mixed emulsion, and stir at a speed of 800 rpm for 10 min to obtain an acrylic resin coating.

[0039] The preparation method of the modified acrylic resin emulsion includes the following steps:

[0040] Step A1: Take 1 part of emulsifier sodium dodecylbenzenesulfonate, 15 parts of methyl methacrylate, 4 parts of butyl acrylate, 1 part of acrylic acid, and 20 parts of deionized water, and stir together at 50 °C for 1 h to form acrylate pre-emulsion a;

[0041] Step A2: Mix 1 part of 15% sodium bicarbonate solution by mass, 1 part of emulsifier sodium dodecylbenzenesulfonate, 5 parts of methyl methacrylate, 2 parts of acrylic acid, 6 parts of butyl acrylate, and 15 parts of deionized water at 45 °C, stir for 30 min, add 0.2 part of initiator 3 wt% potassium persulfate aqueous solution, heat up to 70 °C, react for 1 h, then add the acrylate pre-emulsion a prepared in Step A1, 2 parts of self-cleaning functional monomer, and 0.3 part of 3 wt% potassium persulfate aqueous solution, stir for 15 min, and react for 2 h to obtain the modified acrylic resin emulsion.

[0042] The modified acrylic resin emulsion and the unmodified acrylic resin emulsion are respectively coated on the surface of tinplate, the coating thickness is 30 μm, and it is placed in an oven at 80 °C for drying and curing. After the coating is completely cured, the water contact angle of the coating is measured with a JGW-360B type contact angle tester. It is tested at 3 different positions of each sample, and each position is tested 2 times. The average value of 6 numerical values is taken. The test results show that the water contact angle of the modified acrylic resin emulsion coating is 159°, and the water contact angle of the unmodified acrylic resin emulsion coating is 106°. It can be seen that the superhydrophobic performance of the modified acrylic resin emulsion is provided by the self-cleaning functional monomer.

[0043] The preparation method of the self-cleaning functional monomer includes the following steps:

[0044] Dissolve 0.8 g of 3,3-diphenylpropyl-2-propen-1-ol and 1.2 g of perfluorohexylacetic acid in 50 ml of toluene, add 0.1 g of p-toluenesulfonic acid, and under an anaerobic environment, react at 110 °C for 12 h. Then cool to room temperature, add a 15% potassium bicarbonate solution to adjust the pH to 7, filter and wash to obtain a self-cleaning functional monomer.

[0045] The infrared test chart of the self-cleaning functional monomer is as Figure 1 shown. In the infrared test chart of the self-cleaning functional monomer, the absorption peak at 3054 cm -1 is the C-H stretching vibration peak in the carbon-carbon double bond, and the absorption peak at 2934 cm -1 is the C-H absorption peak of the ethyl group. The absorption peak at 1745 cm -1 is the C=O absorption peak in the ester group. The absorption peaks in the range of 1400 - 1480 cm -1 are the characteristic absorption peaks of the benzene ring. The absorption peak at 1175 cm -1 is the C-F absorption peak, and the absorption peak at 1124 cm -1 is the C-O absorption peak in the ester group.

[0046] The preparation method of the functional additive includes the following steps:

[0047] Disperse 1 g of nano-zinc oxide in 10 mL of hydrogen peroxide solution, stir for 1 h, after centrifugation, filter and wash, and dry at 120 °C for 2 h. Then add the dried nano-zinc oxide to 20 ml of anhydrous N,N-dimethylformamide and stir for 30 min. Under an anaerobic environment, add 0.12 g of 4-maleimidobenzoic acid, 0.01 g of the catalyst 4-dimethylaminopyridine, and 0.25 g of dicyclohexylcarbodiimide, and react at a constant temperature of 60 °C under an anaerobic environment for 24 h. After the reaction, centrifuge, wash, and filter, and dry in a vacuum environment at 60 °C for 12 h to obtain the functional additive.

[0048] Weigh 1 g of nano-zinc oxide and a sample of the multifunctional monomer respectively, and place them in a TGA-101 thermogravimetric analyzer for thermogravimetric analysis. The test found that only a slight mass change occurred in the nano-zinc oxide, which was analyzed to be caused by the decomposition of the adsorbed distilled water. The modified nano-zinc oxide began to decompose at about 220 °C, and the final mass residue rate was 54.7%, which was caused by the decomposition of 4-maleimidobenzene grafted on the surface of the nano-zinc oxide.

[0049] Example 2: An acrylic resin coating with self-cleaning function, calculated by weight, includes the following raw materials: 50 parts of modified acrylic resin emulsion, 5 parts of functional additive, 4 parts of curing agent ethylenediamine, 2.5 parts of film-forming aid, 2 parts of defoaming agent tributyl phosphate, 0.3 part of leveling agent polydimethylsiloxane, 40 parts of deionized water, and 1.2 parts of dispersant sodium polyacrylate.

[0050] Step 1: Take deionized water, modified acrylic resin emulsion, film-forming aid, leveling agent polydimethylsiloxane, and dispersant sodium polyacrylate in parts by weight, and stir at a speed of 650 rpm for 25 min to form an intermediate mixture.

[0051] Step 2: Take defoaming agent tributyl phosphate, curing agent ethylenediamine, functional additive and the mixed emulsion, and stir at a speed of 880 rpm for 15 min to obtain the acrylic resin coating.

[0052] The preparation method of the modified acrylic resin emulsion includes the following steps:

[0053] Step A1: Take 1 part of emulsifier sodium dodecylbenzenesulfonate, 18 parts of methyl methacrylate, 5 parts of butyl acrylate, 1.2 parts of acrylic acid, and 20 parts of deionized water, and stir them together at 50 °C for 1 h to form acrylic ester pre-emulsion a;

[0054] Step A2: Mix 1 part of 15% sodium bicarbonate solution by mass, 1 part of emulsifier sodium dodecylbenzenesulfonate, 2.8 parts of acrylic acid, 6 parts of methyl methacrylate, 7 parts of butyl acrylate, and 20 parts of deionized water, stir at 45 °C for 30 min, add 0.3 part of initiator 4 wt% potassium persulfate aqueous solution, heat up to 80 °C, react for 1 h, then add the acrylic ester pre-emulsion a prepared in Step A1, 2.5 parts of self-cleaning functional monomer, and 0.5 part of initiator 4 wt% potassium persulfate aqueous solution, stir for 15 min, and react for 2 h to obtain the modified acrylic resin emulsion.

[0055] The self-cleaning functional monomer and the functional additive are the same as those in Example 1.

[0056] Example 3: A self-cleaning acrylic resin coating, by weight, includes the following raw materials: 60 parts of modified acrylic resin emulsion, 6 parts of functional additive, 5 parts of curing agent ethylenediamine, 3 parts of film-forming aid, 3 parts of defoaming agent tributyl phosphate, 0.5 part of leveling agent polydimethylsiloxane, 55 parts of deionized water, and 1.5 parts of dispersant sodium polyacrylate.

[0057] Step 1: Take deionized water, modified acrylic resin emulsion, film-forming aid, leveling agent polydimethylsiloxane, and dispersant sodium polyacrylate in parts by weight, and stir at a speed of 800 rpm for 30 min to form a mixed emulsion;

[0058] Step 2: Take defoaming agent tributyl phosphate, curing agent ethylenediamine, functional additive and the mixed emulsion, and stir at a speed of 1000 rpm for 25 min to obtain the acrylic resin coating.

[0059] The preparation method of the modified acrylic resin emulsion includes the following steps:

[0060] Step A1: Take 1.5 parts of emulsifier sodium dodecylbenzenesulfonate, 20 parts of methyl methacrylate, 6 parts of butyl acrylate, 2 parts of acrylic acid, and 20 parts of deionized water. Stir them together at 60 °C for 2 h to form acrylate pre-emulsion a.

[0061] Step A2: Mix 2 parts of a 15% sodium bicarbonate solution by mass, 1.5 parts of emulsifier sodium dodecylbenzenesulfonate, 3 parts of acrylic acid, 10 parts of methyl methacrylate, 9 parts of butyl acrylate, and 25 parts of deionized water at 45 °C. Stir for 30 min, add 0.4 part of 5 wt% potassium persulfate aqueous solution as initiator, heat up to 80 °C, react for 2 h, then add the acrylate pre-emulsion a prepared in Step A1, 3 parts of self-cleaning functional monomer, and 0.6 part of 5 wt% potassium persulfate aqueous solution as initiator. Stir for 15 min and react for 5 h to obtain the modified acrylic resin emulsion.

[0062] The self-cleaning functional monomer and the functional additive are the same as those in Example 1.

[0063] Comparative Example 1: A self-cleaning functional acrylic resin coating, by weight, comprises the following raw materials: 50 parts of acrylic resin emulsion, 5 parts of functional additive, 4 parts of curing agent ethylenediamine, 2.5 parts of film-forming aid, 2 parts of defoaming agent tributyl phosphate, 0.3 part of leveling agent polydimethylsiloxane, 40 parts of deionized water, and 1.2 parts of dispersant sodium polyacrylate salt.

[0064] Step 1: Take by weight deionized water, modified acrylic resin emulsion, film-forming aid, leveling agent polydimethylsiloxane, and dispersant sodium polyacrylate salt. Stir at a speed of 650 rpm for 25 min to form a mixed emulsion.

[0065] Step 2: Take by weight defoaming agent tributyl phosphate, curing agent ethylenediamine, functional additive and the mixed emulsion. Stir at 880 rpm for 15 min to obtain the acrylic resin coating.

[0066] The preparation method of the acrylic resin emulsion includes the following steps:

[0067] Step A1: Take 1 part of emulsifier sodium dodecylbenzenesulfonate, 18 parts of methyl methacrylate, 5 parts of butyl acrylate, 1.2 parts of acrylic acid, and 20 parts of deionized water. Stir them together at 50 °C for 1 h to form acrylate pre-emulsion a.

[0068] Step A2: Mix 1 part of a sodium bicarbonate solution with a mass concentration of 15%, 1 part of the emulsifier sodium dodecylbenzenesulfonate, 2.8 parts of acrylic acid, 6 parts of methyl methacrylate, 7 parts of butyl acrylate, and 20 parts of deionized water at 45°C. Stir for 30 min, add 0.3 part of an initiator, an aqueous solution of 4 wt% potassium persulfate, heat up to 80°C, react for 1 h, then add the acrylate pre-emulsion a prepared in Step A1 and 0.5 part of an initiator, an aqueous solution of 4 wt% potassium persulfate, stir for 15 min, and react for 2 h to obtain a modified acrylic resin emulsion.

[0069] Among them, the functional additives are the same as those in Example 1.

[0070] Comparative Example 2: An acrylic resin coating with self-cleaning function, by weight, includes the following raw materials: 50 parts of modified acrylic resin emulsion, 5 parts of functional additives, 4 parts of curing agent ethylenediamine, 2.5 parts of film-forming aid, 2 parts of defoaming agent tributyl phosphate, 0.3 part of leveling agent polydimethylsiloxane, 40 parts of deionized water, and 1.2 parts of dispersant sodium polyacrylate salt.

[0071] Step 1: Take deionized water, modified acrylic resin emulsion, film-forming aid, leveling agent polydimethylsiloxane, and dispersant sodium polyacrylate salt by weight, and stir at a speed of 650 rpm for 25 min to form a mixed emulsion;

[0072] Step 2: Take defoaming agent tributyl phosphate, curing agent ethylenediamine, functional additives and the mixed emulsion by weight, and stir at a speed of 880 rpm for 15 min to obtain an acrylic resin coating.

[0073] Among them, the preparation method of the modified acrylic resin emulsion includes the following steps:

[0074] Step A1: Take 1 part of emulsifier sodium dodecylbenzenesulfonate, 18 parts of methyl methacrylate, 5 parts of butyl acrylate, 1.2 parts of acrylic acid, and 20 parts of deionized water, and stir together at 50°C for 1 h to form an acrylate pre-emulsion a;

[0075] Step A2: Mix 1 part of a sodium bicarbonate solution with a mass concentration of 15%, 1 part of the emulsifier sodium dodecylbenzenesulfonate, 2.8 parts of acrylic acid, 6 parts of methyl methacrylate, 7 parts of butyl acrylate, and 20 parts of deionized water at 45°C. Stir for 30 min, add 0.3 part of an initiator, an aqueous solution of 4 wt% potassium persulfate, heat up to 80°C, react for 1 h, then add the acrylate pre-emulsion a prepared in Step A1, 2.5 parts of self-cleaning functional monomer, and 0.5 part of an initiator, an aqueous solution of 4 wt% potassium persulfate, stir for 15 min, and react for 2 h to obtain a modified acrylic resin emulsion.

[0076] Among them, the self-cleaning functional monomer is the same as that in Example 1.

[0077] Comparative Example 3: An acrylic resin coating with self-cleaning function, by weight, includes the following raw materials: 50 parts of acrylic resin emulsion, 5 parts of functional additive, 4 parts of curing agent ethylenediamine, 2.5 parts of film-forming aid, 2 parts of defoaming agent tributyl phosphate, 0.3 part of leveling agent polydimethylsiloxane, 40 parts of deionized water, and 1.2 parts of dispersant sodium polyacrylate.

[0078] Step 1: Take deionized water, modified acrylic resin emulsion, film-forming aid, leveling agent polydimethylsiloxane, and dispersant sodium polyacrylate by weight, and stir at a speed of 650 rpm for 25 min to form a mixed emulsion.

[0079] Step 2: Take defoaming agent tributyl phosphate, curing agent ethylenediamine, functional additive and the mixed emulsion by weight, and stir at a speed of 880 rpm for 15 min to obtain the acrylic resin coating.

[0080] The preparation method of the acrylic resin emulsion includes the following steps:

[0081] Step A1: Take 1 part of emulsifier sodium dodecylbenzenesulfonate, 18 parts of methyl methacrylate, 5 parts of butyl acrylate, 1.2 parts of acrylic acid, and 20 parts of deionized water, and stir together at 50 °C for 1 h to form acrylate pre-emulsion a.

[0082] Step A2: Mix 1 part of 15% sodium bicarbonate solution by mass, 1 part of emulsifier sodium dodecylbenzenesulfonate, 2.8 parts of acrylic acid, 6 parts of methyl methacrylate, 7 parts of butyl acrylate, and 20 parts of deionized water at 45 °C, stir for 30 min, add 0.3 part of 4 wt% potassium persulfate aqueous solution as initiator, heat up to 80 °C, react for 1 h, then add the acrylate pre-emulsion a prepared in Step A1 and 0.5 part of 4 wt% potassium persulfate aqueous solution as initiator, stir for 15 min, and react for 2 h to obtain the modified acrylic resin emulsion.

[0083] Performance testing:

[0084] The acrylic resin coatings prepared in Examples 1-3 and Comparative Examples 1-4 of the present invention were evenly coated on the surface of tinplate with a coating thickness of 30 μm. After curing in an oven at 80 °C for 10 h, samples meeting the specifications were processed. The water contact angle of the samples was measured using a JGW-360B type contact angle tester. The test was carried out at 3 different positions on each sample, and each position was measured 2 times. The average value of 6 measurements was taken to judge the hydrophobic performance of the samples. The samples were placed in an oven at 180 °C and taken out after 24 h to observe whether there were phenomena such as film peeling, blistering, and yellowing, and the heat resistance of the coatings was evaluated. Referring to the GB / T 16777-2008 standard, coatings were prepared in a coating mold frame. Two specimens with an area of (150×150) mm were cut. The specimens were placed on a water-permeable plate, clamped after adding a metal mesh and a 7-hole disc of the same size. The test pressure was 0.3 MPa, and the pressure holding time was 30 min. The water seepage situation on the non-windward side of the specimens was observed. The test results are recorded in the following table.

[0085] Water contact angle / ° Heat resistance Waterproof property Example 1 156 No phenomenon No water seepage Example 2 162 No phenomenon No water seepage Example 3 158 No phenomenon No water seepage Comparative example 1 107 No phenomenon Slight water seepage Comparative example 2 152 Partial peeling, serious foaming, serious yellowing No water seepage Comparative example 3 102 Massive yellowing, bubbles, peeling Partial water seepage

[0086] It can be concluded from the above table that in high-temperature environments, Examples 1-3 of the present invention can maintain the coatings without change, have good heat resistance, and the water contact angles are all greater than 150°, possessing superhydrophobic performance, self-cleaning performance, and waterproof performance.

[0087] In Comparative Example 1, no self-cleaning functional monomer was added during the preparation of the acrylic resin emulsion, and only functional additives were added. Therefore, the prepared acrylic resin coating does not contain fluorine-containing groups and benzene rings, only contains maleimide-based benzene structures and inorganic nanomaterials. Therefore, the coating has good heat resistance, does not possess superhydrophobic and self-cleaning functions, and the waterproof effect is also poor.

[0088] In Comparative Example 2, no functional additives were added during the preparation of the acrylic resin coating, and only self-cleaning functional monomers were added. Therefore, the prepared acrylic resin coating does not contain maleimide-based benzene structures and inorganic nanomaterials, only contains benzene rings and fluorine-containing groups, and only the benzene ring has heat resistance. Therefore, the heat resistance performance of the coating is poor.

[0089] In Comparative Example 3, no self-cleaning functional monomer and functional additives were added during the preparation of the acrylic resin coating. Therefore, the prepared acrylic resin coating does not contain maleimide-based benzene structures, inorganic nanomaterials, benzene rings, and fluorine-containing groups. Therefore, all the properties of the coating are the worst.

[0090] The above content is only an example and explanation of the concept of the present invention. Those skilled in the art of the present technology can make various modifications, supplements, or use similar methods to replace the specific embodiments described, as long as they do not deviate from the concept of the invention or exceed the scope defined by this claim book, they should all belong to the protection scope of the present invention.

Claims

1. An acrylic resin coating with self-cleaning function, by weight, includes the following raw materials: 40-60 parts of modified acrylic resin emulsion, 3-6 parts of functional additive, 2-5 parts of curing agent, 1.5-3 parts of film-forming auxiliary, 1-3 parts of defoamer, 0.2-0.5 parts of leveling agent, 30-55 parts of deionized water, 1-1.5 parts of dispersant; The modified acrylic resin emulsion includes the following raw materials by weight: 20-30 parts of methyl methacrylate, 10-15 parts of butyl acrylate, 3-5 parts of acrylic acid, 2-3 parts of emulsifier, 30-45 parts of deionized water, 2-5 parts of self-cleaning functional monomer, 1-2 parts of potassium bicarbonate solution, 0.5-1 part of initiator; The preparation method of the modified acrylic resin emulsion includes the following steps: Step A1: Take 1-1.5 parts of emulsifier, 15-20 parts of methyl methacrylate, 4-6 parts of butyl acrylate, 1-2 parts of acrylic acid, 15-20 parts of deionized water, and stir them together for 1-2 h at 50-60 °C to form acrylate pre-emulsion a; Step A2: Mix 1-2 parts of sodium bicarbonate solution, 1-1.5 parts of emulsifier, 5-10 parts of methyl methacrylate, 6-9 parts of butyl acrylate, 2-3 parts of acrylic acid, 15-25 parts of deionized water, stir for 30-50 min at 45-60 °C, add 0.2-0.4 parts of initiator, heat up to 70-80 °C, react for 1-2 h, then add the acrylate pre-emulsion a prepared in Step A1, 2-3 parts of self-cleaning functional monomer, 0.3-0.6 parts of initiator, stir for 15-30 min, and react for 2-5 h to obtain the modified acrylic resin emulsion.

2. The acrylic resin coating with self-cleaning function according to claim 1, wherein The curing agent is ethylenediamine; the dispersant is polyvinylpyrrolidone or sodium polyacrylate.

3. The acrylic resin coating with a self-cleaning function according to claim 1, characterized in that, The leveling agent is aqueous acrylate copolymer or polydimethylsiloxane; the defoamer is tributyl phosphate or fatty alcohol polyoxyethylene ether.

4. A kind of acrylic resin coating with self-cleaning function according to claim 1, characterized in that, The emulsifier is any one of OP-10, sodium dodecylbenzenesulfonate, and sodium dodecylsulfonate.

5. The acrylic resin coating with a self-cleaning function according to claim 1, wherein In Step A2, the initiator is 3-5 wt% aqueous solution of sodium persulfate or 3-5 wt% aqueous solution of potassium persulfate; the mass concentration of the sodium bicarbonate solution is 15-25%.

6. The acrylic resin coating with a self-cleaning function according to claim 1, characterized in that, The preparation method of the self-cleaning functional monomer includes the following steps: Dissolve 3,3-diphenylpropyl-2-propen-1-ol and perfluorohexylacetic acid in toluene, add p-toluenesulfonic acid, and react for 12-24 h at 100-110 °C in an anaerobic environment. Then cool to room temperature, add potassium bicarbonate solution to adjust the pH to 7-8, and filter and wash to obtain the self-cleaning functional monomer.

7. An acrylic resin coating with a self-cleaning function according to claim 6, characterized in that, The mass concentration of the potassium bicarbonate solution is 10-15%.

8. A kind of acrylic resin coating with self-cleaning function according to claim 1, characterized in that, The preparation method of the functional additive includes the following steps: Disperse zinc oxide nanoparticles in a hydrogen peroxide solution, stir for 1 - 2 h, after centrifugation, filter and wash, and dry in an environment of 110 - 120 °C for 2 - 5 h. Then add the dried zinc oxide nanoparticles to anhydrous N,N - dimethylformamide and stir for 30 - 50 min. Under an anaerobic environment, add 4 - maleimidobenzoic acid, a catalyst, and dicyclohexylcarbodiimide, and react at a constant temperature of 40 - 60 °C in an anaerobic environment for 12 - 24 h. After the reaction, centrifuge, wash and filter, and dry in a vacuum environment of 60 - 80 °C for 12 - 24 h to obtain a functional additive.

9. The acrylic resin coating with self-cleaning function according to claim 8, characterized in that, The catalyst is 4 - dimethylaminopyridine or N - methylmorpholine.

10. The preparation method of an acrylic resin coating with self-cleaning function according to claim 1, characterized in that, It includes the following steps: Step 1: Take parts by weight of deionized water, a modified acrylic resin emulsion, a film-forming aid, a leveling agent, and a dispersant, and stir at a speed of 500 - 800 rpm for 20 - 30 min to form a mixed emulsion; Step 2: Take parts by weight of an antifoaming agent, a curing agent, and a functional additive and stir with the mixed emulsion at a speed of 800 - 1000 rpm for 10 - 25 min to obtain an acrylic resin coating.

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