A waterborne anti-fouling metal baking paint and a preparation method thereof

Abstract

The present application belongs to the technical field of water-based paint, and particularly relates to a water-based anti-fouling metal baking paint and a preparation method thereof. The water-based anti-fouling metal baking paint is prepared from the following raw materials in parts by mass: acrylic resin 48-60 parts, fluorine-modified acrylic resin 6-10 parts, methyl etherified amino resin 9-15 parts, p-toluene sulfonic acid 0.2-0.8 parts, composite filler 5-10 parts, film-forming aid 5-10 parts, polyurethane thickening agent 0.2-0.4 parts, adhesion promoter 1-2 parts, pH regulator 0.3-0.5 parts, wetting and leveling agent 0.3-0.8 parts, defoaming agent 0.2-0.6 parts, and water 10-15 parts. The preparation method of the water-based anti-fouling metal baking paint is simple, and the prepared water-based anti-fouling metal baking paint has excellent anti-fouling and waterproof performance and good mechanical properties.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of water-based paint, and particularly relates to a water-based anti-fouling metal baking paint and a preparation method thereof. BACKGROUND

[0002] In recent years, metal materials are increasingly applied in the fields of construction, household appliances, automobiles, ships and ocean engineering. Therefore, coating protection of metal surfaces has become an indispensable process link.

[0003] Traditional solvent-based metal baking paint has long dominated the market due to its excellent film-forming property, hardness, adhesion and corrosion resistance. However, such paint releases a large amount of volatile organic compounds in the production and use process, causing harm to the environment and workers. Therefore, the development of environmentally friendly paint has become an inevitable trend of the industry.

[0004] Water-based metal baking paint uses water as the main dispersion medium, which is safe and environmentally friendly. The water-based acrylic baking paint includes water-based acrylic resin, curing agent and various water-based additives, and has good film-forming property and weather resistance, and can form a hard paint film. Compared with traditional solvent-based metal baking paint, water-based metal baking paint still has certain limitations in hardness, wear resistance and other properties. Therefore, in order to improve the overall comprehensive performance of the paint film, the modification and optimization of raw materials and production process are the key content for the development of the paint industry.

[0005] The Chinese patent application file with the publication number CN109294369A discloses a water-based acrylic baking paint, which is composed of the following raw materials in parts by weight: water-based acrylic resin 50-80 parts, modified filler 10-20 parts, distilled water 20-30 parts, defoaming agent 0.3-0.5 parts, leveling agent 0.3-0.5 parts, wetting agent 0.3-0.5 parts, thickening agent 0.3-0.5 parts, organic acid 3-5 parts, and low-melting-point alloy 3-5 parts. The technical solution improves the impact resistance through the synergistic effect of the modified filler (graphene oxide and multi-walled carbon nanotube) and the organic acid. However, when applied to application scenarios such as kitchen utensils and bathroom products that require cleanliness and corrosion resistance, the paint film is prone to dust and oil stains, and the metal substrate is prone to corrosion and rust. Therefore, the baking paint cannot meet the needs of anti-fouling and anti-corrosion scenarios, and the functional coverage is narrow. SUMMARY

[0006] The existing water-based metal baking paint has poor stain resistance. In order to solve this problem, the present application provides a water-based anti-fouling metal baking paint and a preparation method thereof.

[0007] In order to achieve the purpose of the present application, the following technical solutions are adopted:

[0008] The present application provides a water-based anti-fouling metal baking paint, which is prepared from the following raw materials in mass parts:

[0009] acrylic resin 48-60 parts, fluorine modified acrylic resin 6-10 parts, methyl etherified amino resin 9-15 parts, p-toluene sulfonic acid 0.2-0.8 parts, composite filler 5-10 parts, film forming aid 5-10 parts, polyurethane thickening agent 0.2-0.4 parts, adhesion promoter 1-2 parts, pH regulator 0.3-0.5 parts, wetting and leveling agent 0.3-0.8 parts, defoaming agent 0.2-0.6 parts, water 10-15 parts.

[0010] By adopting the above technical scheme, the acrylic resin and the methyl etherified amino resin are baked at high temperature under the catalysis of the p-toluene sulfonic acid to form a dense three-dimensional network cross-linked structure, so that the paint film has high hardness and excellent wear resistance and other properties. The fluorine modified acrylic resin migrates to the surface of the paint film and enriches during the curing process of the paint film, forming a dense protective layer, so that water and oil are difficult to wet and adhere, and the stain resistance is enhanced; the addition of the adhesion promoter, the film forming aid and other aids endows the paint film with strong adhesion, workability and storage stability and other properties.

[0011] Preferably, the preparation method of the fluorine modified acrylic resin comprises the following steps:

[0012] (1) uniformly mix methyl methacrylate, 2-ethylhexyl acrylate, hydroxypropyl acrylate, methacrylic acid, vinyl triethoxysilane, N-ethyl perfluorooctyl sulfonamide ethyl acrylate, emulsifier and water to obtain a pre-emulsion;

[0013] (2) uniformly mix ammonium persulfate and water to obtain an initiator aqueous solution;

[0014] (3) under an anaerobic atmosphere, uniformly mix part of the pre-emulsion, part of the initiator aqueous solution and water, and then perform a first reaction by heating; then synchronously drop the remaining pre-emulsion and the remaining initiator aqueous solution, and after the dropping is completed, perform a second reaction;

[0015] (4) continue to heat the reaction system of step (3) to react; after the reaction is completed, cool, adjust the pH to 7.5-8.5, filter, and obtain the fluorine modified acrylic resin.

[0016] By adopting the above technical scheme, the pre-emulsification and monomer dropping method is adopted, so that the reaction is stable, the monomer conversion rate is high, the obtained emulsion particle size is small and uniformly distributed, which makes the resin itself have good storage stability and is not easy to separate or scale; the fluorine and silicon elements are directly introduced into the polymer main chain, avoiding the problems of easy migration and easy precipitation of small molecule additives, and ensuring the long-term effectiveness and durability of the stain resistance and adhesion performance.

[0017] Preferably, in the step (1), the mass ratio of methyl methacrylate, 2-ethylhexyl acrylate, hydroxypropyl acrylate, methacrylic acid, vinyl triethoxysilane, N-ethyl perfluorooctyl sulfonamide ethyl acrylate and emulsifier is (22-26):(12-15):(7-9):(2-4):(3-6):(10-14):(1.5-3).

[0018] By adopting the above technical solution, the ratio of methyl methacrylate and 2-ethylhexyl acrylate ensures that the resin can form a high-hardness paint film and has sufficient cohesive flexibility, avoiding the problem of brittle paint film under high crosslinking degree, so that the final paint film is both hard and tough, and has good impact resistance; the content ratio of fluorine-silicon ensures that there is enough fluorine element to provide antifouling property, and at the same time there is a proper amount of silicon element to anchor on the metal substrate; the amount of hydroxypropyl acrylate, methacrylic acid and emulsifier ensures the water dispersibility, crosslinking degree and stability of the emulsion.

[0019] Preferably, in the step (1), the mixing time is 30-45 min.

[0020] By adopting the above technical solution, the time range can provide sufficient time to form a stable and uniform pre-emulsion system, laying a foundation for smooth polymerization.

[0021] Preferably, in the step (2), the mass ratio of ammonium persulfate to water is 1:(25-30); the amount of ammonium persulfate is 1.1%-1.2% of the total mass of methyl methacrylate, 2-ethylhexyl acrylate, hydroxypropyl acrylate, methacrylic acid, vinyl triethoxysilane and N-ethyl perfluorooctyl sulfonamide ethyl acrylate.

[0022] By adopting the above technical solution, the concentration of the initiator aqueous solution can make the solution uniformly and slowly added to the reaction system. The amount of ammonium persulfate can ensure that there are enough free radicals to initiate all monomers, ensuring high conversion rate and avoiding excessive residual unreacted monomers affecting the stability of the emulsion and the performance of the paint film.

[0023] Preferably, in the step (3), the temperature of the first reaction is 80-85℃, and the time of the first reaction is 15-20 min; the time of the second reaction is 1.5-2.5 h.

[0024] By adopting the above technical solution, in the temperature range of 80-85℃, the monomers can be initiated to polymerize in the emulsifier micelles to form initial polymer latex particles with uniform size and consistent activity; if the temperature is too low, it is difficult to initiate; if the temperature is too high, nucleation is too fast and too much, resulting in uneven particle size; the second reaction provides sufficient time for the residual unreacted monomers to fully react.

[0025] Preferably, in the step (4), the temperature of the reaction is 90-95℃, and the reaction time is 1-2h.

[0026] By adopting the technical scheme, the temperature in the post-treatment stage of the step (4) is increased, energy is provided for the ammonium persulfate which may not have reacted, the residual monomers in the system are attacked, the conversion rate of the monomers is increased, the movement and rearrangement of the polymer segments are promoted, the structure of the latex particles is more stable, and a more compact paint film is formed.

[0027] Preferably, the composite filler is PTFE wax micro powder and zinc phosphate prepared according to a mass ratio of (1-2) : 1.

[0028] By adopting the technical scheme, in the process of baking and curing of the paint film, the PTFE wax micro powder migrates to the outermost layer of the paint film, forms a low-surface-energy smooth protective layer, and provides water and oil resistance; the zinc phosphate is close to the lower layer of the paint film near the metal substrate, reacts with the metal substrate to form a dense passivation protective layer, effectively inhibits electrochemical corrosion, and provides rust protection. The ratio of (1-2) : 1 can meet the requirements of comprehensive protection performance of metal baking paint.

[0029] Preferably, the film-forming aid is a mixture of ethylene glycol monobutyl ether and diethylene glycol monobutyl ether according to a mass ratio of 1 : (1-3).

[0030] By adopting the technical scheme, the evaporation speed of ethylene glycol monobutyl ether is relatively fast, and the evaporation speed of diethylene glycol monobutyl ether is slow; in the initial stage of baking of the paint film, ethylene glycol monobutyl ether which evaporates fast can quickly soften resin particles, and promote them to be closely packed, laying a foundation for film formation; after the water and ethylene glycol monobutyl ether evaporate, diethylene glycol monobutyl ether which evaporates slowly remains in the paint film, continuously softens the resin particles, and finally forms a smooth and defect-free paint film.

[0031] In the second aspect, the application provides a preparation method of the water-based anti-fouling metal baking paint, comprising the following steps:

[0032] S1: uniformly mixing acrylic resin, fluorine-modified acrylic resin, film-forming aid and water to obtain a first mixture;

[0033] S2: uniformly mixing the first mixture, polyurethane thickening agent, adhesion promoter, pH regulator, wetting and leveling agent and defoaming agent to obtain a second mixture;

[0034] S3: uniformly mixing the second mixture and the composite filler to obtain a third mixture;

[0035] S4: uniformly mixing the third mixture, methyl etherified amino resin and p-toluenesulfonic acid, filtering, and obtaining the water-based anti-fouling metal baking paint.

[0036] By adopting the technical scheme, the preparation method firstly mixes the two resins with the film forming aid and water, ensures that the resin system is fully wetted and initially diluted, then adds various aids to provide good system stability for subsequent processes, then adds fillers to enable the fillers to be fully wrapped by the resins and aids, and finally adds the methylated amino resin and p-toluenesulfonic acid in the last step to avoid early failure of the crosslinking component; the baking paint prepared by the preparation method has excellent storage stability, workability and film forming property and the like.

[0037] In summary, the beneficial effects of the present application are:

[0038] (1) The present application prepares a fluorine-modified acrylic resin, which is introduced into an acrylic resin metal baking paint system, so that the prepared paint film has water resistance, oil resistance and anti-adhesion properties; at the same time, the fluorine-silicon modification optimizes the polymer chain structure, so that the paint film has better flexibility while maintaining high hardness and scratch resistance, and adapts to the processing deformation of metal;

[0039] (2) The present application introduces PTFE wax micro powder and zinc phosphate to prepare a filler, the PTFE wax micro powder mainly provides surface anti-fouling smoothness, and the zinc phosphate mainly provides bottom anti-rust and corrosion resistance, so that the paint film has surface anti-fouling performance and internal corrosion resistance at the same time;

[0040] (3) The present application adjusts and optimizes the ratio of film forming aids, effectively prevents burst holes caused by premature drying of the surface and failure of the solvent to escape, and prevents paint film defects such as orange peel and uneven gloss caused by insufficient fusion of resin particles;

[0041] (4) The preparation method of the present application is safe and simple to operate, the prepared baking paint has stable quality, and can be applied to industrial production. BRIEF DESCRIPTION OF DRAWINGS

[0042] Figure 1 The infrared spectrum of the fluorine-modified acrylic resin of the present application. DETAILED DESCRIPTION

[0043] The technical scheme of the present application will be explained in detail below with reference to several representative embodiments of the present application.

[0044] The experimental methods used in the following examples and comparative examples are conventional methods unless otherwise specified. The materials, reagents and the like used in the following examples and comparative examples can be obtained from commercial channels unless otherwise specified.

[0045] Acrylic acid-2-ethylhexyl ester: Shanghai Araldin Biochemical Technology Co., Ltd.;

[0046] N-ethyl perfluorooctyl sulfonamide ethyl acrylate: Wuxi Kaiduerui Pharmaceutical Technology Co., Ltd.;

[0047] Methyl methacrylate: industrial grade, 99.9%, Jinan Aochen Chemical Co., Ltd.;

[0048] Methyl methacrylate: industrial grade, 99.9%, Jinan Aochen Chemical Co., Ltd.;

[0049] Methyl methacrylate: industrial grade, 99.9%, Jinan Aochen Chemical Co., Ltd.;

[0050] Vinyl triethoxysilane: Hubei Xingyan New Material Technology Co., Ltd.;

[0051] Ammonium persulfate: National Pharmaceutical Group Chemical Reagent Co., Ltd.;

[0052] Emulsifier: sodium dodecyl sulfate, Shaoxing Zhedong Chemical Factory;

[0053] Acrylic resin: Wuhan Shuangli Chemical Co., Ltd.;

[0054] Methyl ether amino resin: 98%, Wuhan Baiyite Chemical Co., Ltd.;

[0055] p-Toluene sulfonic acid: industrial grade, total acidity ≥93%, Likao Chemical Co., Ltd.;

[0056] PTFE wax powder: particle size 3-5 μm, Guangzhou Songbai Chemical Co., Ltd.;

[0057] Ethylene glycol monobutyl ether: industrial grade, 99.5%, Nanjing Danpei Chemical Co., Ltd.;

[0058] Diethylene glycol monobutyl ether: industrial grade, 99.5%, Nanjing Danpei Chemical Co., Ltd.;

[0059] Polyurethane thickener: polyurethane thickener RA1107, Shanghai Lite Chemical Technology Co., Ltd.;

[0060] Adhesion promoter: adhesion promoter SN-7023, 60%, Shanghai Shenzhu Chemical Technology Co., Ltd.;

[0061] pH regulator: DMEA, 99%, Jiangsu Taihu New Material Holding Co., Ltd.;

[0062] Wetting and leveling agent: wetting and leveling agent HT-298, 99%, Nantong Hantai Chemical Co., Ltd.;

[0063] Defoamer: defoamer SN-6788, 100%, Shanghai Shenzhu Chemical Technology Co., Ltd.

[0064] Preparation Example 1

[0065] The preparation method of a fluorine-modified acrylic resin according to the present preparation example is as follows:

[0066] (1) Into a reactor, 2 kg of deionized water and 40 g of emulsifier were added, stirring was started, and 460 g of methyl methacrylate, 300 g of 2-ethylhexyl acrylate, 160 g of hydroxypropyl acrylate, 60 g of methacrylic acid, 60 g of vinyl triethoxysilane and 220 g of N-ethyl perfluorooctylsulfonamidoethyl acrylate were slowly added, stirring was carried out at a rotation speed of 600 rpm for 40 min to obtain a pre-emulsion;

[0067] (2) 1.4 g of ammonium persulfate was mixed with 35 g of deionized water, and stirring was carried out for 10 min to obtain an aqueous initiator solution;

[0068] (3) Into the reactor, 1 / 5 of the pre-emulsion prepared in step (1) and 10 g of water were added, stirring and nitrogen protection were started, the temperature was raised to 82℃, 1 / 4 of the aqueous initiator solution prepared in step (2) was added, and reaction was carried out for 15 min; then the remaining 4 / 5 of the pre-emulsion and the remaining 3 / 4 of the aqueous initiator solution were synchronously added dropwise, after the dropwise addition was completed, secondary reaction was carried out for 2.5 h;

[0069] (4) The reaction system of step (3) was continuously heated to 95℃ and reacted for 2 h; after the reaction was completed, the temperature was cooled to room temperature, the pH was adjusted to 8, filtration was carried out, and a fluorine-modified acrylic resin was obtained.

[0070] The infrared spectrum of the fluorine-modified acrylic resin is shown in Figure 1 ; as shown in Figure 1 , 3382 cm -1 is the characteristic absorption peak of hydroxyl, 2957 cm -1 is the characteristic absorption peak of -C-H bond; 1728 cm -1 , 1243 cm -1 and 1173 cm -1 are the characteristic absorption peaks of C=O bond and C-O-C bond; 1405 cm -1 is the characteristic absorption peak of -CH2 connected with -CF2; 1114 cm -1 is the characteristic absorption peak of -CF3; 1075 cm -1 and 1028 cm -1 are the characteristic absorption peaks of Si-O-Si bond; the characteristic absorption peaks of each monomer unit are present in the spectrum, indicating that the fluorine-modified acrylic resin is successfully synthesized.

[0071] Preparation Example 2

[0072] The preparation method of a fluorine-modified acrylic resin in this preparation example is as follows:

[0073] (1) Into a reaction kettle, 2 kg of deionized water and 30 g of emulsifier were added, stirring was started, and 520 g of methyl methacrylate, 240 g of 2-ethylhexyl acrylate, 180 g of hydroxypropyl acrylate, 40 g of methacrylic acid, 120 g of vinyl triethoxysilane and 240 g of N-ethyl perfluorooctyl sulfonamidoethyl acrylate were slowly added, stirring was carried out at a rotation speed of 600 rpm for 35 min to obtain a pre-emulsion;

[0074] (2) 1.55 g of ammonium persulfate was mixed with 45 g of deionized water, stirring was carried out for 10 min to obtain an initiator aqueous solution;

[0075] (3) Into a reaction kettle, 1 / 5 of the pre-emulsion prepared in step (1) and 10 g of water were added, stirring and nitrogen protection were started, the temperature was raised to 85°C, 1 / 4 of the initiator aqueous solution prepared in step (2) was added, and reaction was carried out for 20 min; then the remaining 4 / 5 of the pre-emulsion and the remaining 3 / 4 of the initiator aqueous solution were synchronously added dropwise, after the dropwise addition was completed, secondary reaction was carried out for 2 h;

[0076] (4) The reaction system of step (3) was continuously raised to 90°C for reaction for 2 h; after the reaction was completed, the temperature was cooled to room temperature, the pH was adjusted to 8.5, and filtration was carried out to obtain a fluorine-modified acrylic resin.

[0077] Preparation Example 3

[0078] The preparation method of a fluorine-modified acrylic resin in the present preparation example is as follows:

[0079] (1) Into a reaction kettle, 2 kg of deionized water and 60 g of emulsifier were added, stirring was started, and 500 g of methyl methacrylate, 280 g of 2-ethylhexyl acrylate, 140 g of hydroxypropyl acrylate, 80 g of methacrylic acid, 100 g of vinyl triethoxysilane and 280 g of N-ethyl perfluorooctyl sulfonamidoethyl acrylate were slowly added, stirring was carried out at a rotation speed of 600 rpm for 45 min to obtain a pre-emulsion;

[0080] (2) 1.65 g of ammonium persulfate was mixed with 42 g of deionized water, stirring was carried out for 10 min to obtain an initiator aqueous solution;

[0081] (3) Into a reaction kettle, 1 / 5 of the pre-emulsion prepared in step (1) and 10 g of water were added, stirring and nitrogen protection were started, the temperature was raised to 80°C, 1 / 4 of the initiator aqueous solution prepared in step (2) was added, and reaction was carried out for 20 min; then the remaining 4 / 5 of the pre-emulsion and the remaining 3 / 4 of the initiator aqueous solution were synchronously added dropwise, after the dropwise addition was completed, secondary reaction was carried out for 1.5 h;

[0082] (4) The reaction system of step (3) was continuously raised to 90°C for reaction for 1 h; after the reaction was completed, the temperature was cooled to room temperature, the pH was adjusted to 7.5, and filtration was carried out to obtain a fluorine-modified acrylic resin.

[0083] Example 1

[0084] The water-based anti-fouling metal baking paint of this example is prepared from the following raw materials by mass:

[0085] Acrylic resin 5.2 kg, fluorine-modified acrylic resin prepared in Preparation Example 1 0.8 kg, methyl etherified amino resin 1.2 kg, p-toluenesulfonic acid 0.04 kg, PTFE wax powder 0.4 kg, zinc phosphate 0.2 kg, ethylene glycol monobutyl ether 0.2 kg, diethylene glycol monobutyl ether 0.6 kg, polyurethane thickening agent 0.04 kg, adhesion promoter 0.2 kg, pH adjuster 0.04 kg, wetting and leveling agent 0.06 kg, defoaming agent 0.04 kg, water 1 kg.

[0086] The preparation method of the water-based anti-fouling metal baking paint of this example is as follows:

[0087] S1: Mix acrylic resin, fluorine-modified acrylic resin, ethylene glycol monobutyl ether, diethylene glycol monobutyl ether and water, stir at a speed of 600 rpm for 10 min to obtain a first mixture;

[0088] S2: Mix the first mixture, polyurethane thickening agent, adhesion promoter, pH adjuster, wetting and leveling agent and defoaming agent uniformly, stir at a speed of 600 rpm for 20 min to obtain a second mixture;

[0089] S3: Mix the second mixture, PTFE wax powder and zinc phosphate uniformly, stir at a speed of 800 rpm for 15 min to obtain a third mixture;

[0090] S4: Mix the third mixture, methyl etherified amino resin and p-toluenesulfonic acid uniformly, stir at a speed of 800 rpm for 15 min, filter to obtain the water-based anti-fouling metal baking paint.

[0091] Example 2

[0092] The water-based anti-fouling metal baking paint of this example is prepared from the following raw materials by mass:

[0093] Acrylic resin 6 kg, fluorine-modified acrylic resin prepared in Preparation Example 1 0.6 kg, methyl etherified amino resin 1.5 kg, p-toluenesulfonic acid 0.06 kg, PTFE wax powder 0.25 kg, zinc phosphate 0.25 kg, ethylene glycol monobutyl ether 0.2 kg, diethylene glycol monobutyl ether 0.4 kg, polyurethane thickening agent 0.02 kg, adhesion promoter 0.1 kg, pH adjuster 0.05 kg, wetting and leveling agent 0.08 kg, defoaming agent 0.02 kg, water 1.2 kg.

[0094] The preparation method of the water-based anti-fouling metal baking paint of this example is the same as that of Example 1.

[0095] Example 3

[0096] A water-based antifouling metal baking paint according to the present example was prepared from the following raw materials by mass:

[0097] Acrylic resin 5.6 kg, fluorine-modified acrylic resin prepared in Preparation Example 2 1 kg, methyl etherified amino resin 1 kg, p-toluenesulfonic acid 0.08 kg, PTFE wax fine powder 0.4 kg, zinc phosphate 0.4 kg, ethylene glycol monobutyl ether 0.25 kg, diethylene glycol monobutyl ether 0.25 kg, polyurethane thickener 0.04 kg, adhesion promoter 0.18 kg, pH adjuster 0.04 kg, wetting and leveling agent 0.05 kg, defoaming agent 0.06 kg, water 1.5 kg.

[0098] A method for preparing a water-based antifouling metal baking paint according to the present example, the specific steps being the same as in Example 1.

[0099] Example 4

[0100] A water-based antifouling metal baking paint according to the present example was prepared from the following raw materials by mass:

[0101] Acrylic resin 5.6 kg, fluorine-modified acrylic resin prepared in Preparation Example 2 1 kg, methyl etherified amino resin 1 kg, p-toluenesulfonic acid 0.08 kg, PTFE wax fine powder 0.4 kg, zinc phosphate 0.4 kg, ethylene glycol monobutyl ether 0.25 kg, diethylene glycol monobutyl ether 0.25 kg, polyurethane thickener 0.04 kg, adhesion promoter 0.18 kg, pH adjuster 0.04 kg, wetting and leveling agent 0.05 kg, defoaming agent 0.06 kg, water 1.5 kg.

[0102] A method for preparing a water-based antifouling metal baking paint according to the present example, the specific steps being the same as in Example 1.

[0103] Comparative Example 1

[0104] The difference from Example 1 is that the same amount of acrylic resin is used instead of fluorine-modified acrylic resin in the present comparative example.

[0105] Comparative Example 2

[0106] The difference from Example 1 is that the amount of N-ethyl perfluorooctyl sulfonamide ethyl acrylate is reduced to 50 g in the preparation method of fluorine-modified acrylic resin in the present comparative example.

[0107] Comparative Example 3

[0108] The difference from Example 1 is that the amount of vinyl triethoxysilane is reduced to 10 g in the preparation method of fluorine-modified acrylic resin in the present comparative example.

[0109] Comparative Example 4

[0110] The difference between this comparative example and Example 1 is that the composite filler in this comparative example is PTFE wax micro powder and zinc phosphate prepared according to a mass ratio of 1:3.

[0111] Comparative Example 5

[0112] The difference between this comparative example and Example 1 is that the film forming aid in this comparative example is ethylene glycol monobutyl ether.

[0113] Related performance tests

[0114] The water-based anti-fouling metal baking paint prepared in Examples 1-4 and Comparative Examples 1-5 was prepared into a wet film on a clean metal product, placed in a 150°C oven for 20 min, and after cooling, the performance of the paint film was tested, and the results are shown in Tables 1 and 2.

[0115] The test method is as follows:

[0116] Hardness: tested according to GB / T 6739-2022 “Pigments and varnishes - Determination of film hardness by pencil method”, pencil hardness of the baking paint coating was determined using a pencil hardness tester, 1 kg weight, and the corresponding pencil model when the coating was free of marks was recorded;

[0117] Scratch resistance: a nylon fingernail was used to draw a straight line scratch about 5 cm long on the surface of the coating at a moderate and uniform speed, 3 scratches were drawn in parallel in the same area with an interval of about 2 mm, the debris around the scratches was wiped off with a soft cloth, and the scratch area was observed under a strong light flashlight from a low angle (10°-30°) in a dark room environment;

[0118] Acid resistance: tested according to GB / T 9274-1988 “Pigments and varnishes - Determination of resistance to liquid media”;

[0119] Alkali resistance: tested according to GB / T 9274-1988 “Pigments and varnishes - Determination of resistance to liquid media”;

[0120] Alcohol resistance: 500 g of weight was wrapped with 2 layers of cotton gauze, alcohol was dropped on the cotton gauze so that the cotton gauze fully absorbed the alcohol, and the coating was checked after wiping back and forth 200 times at a speed of 2 seconds per round within a range of 60 mm in length;

[0121] Water boiling resistance: water was heated to and maintained at 80±2°C, then the sample was completely immersed in hot water, and after 1 h of boiling, it was taken out and left to stand at room temperature, and the coating was checked;

[0122] Water contact angle: tested using a contact angle measuring instrument, temperature 23±2°C, relative humidity 50±3%, water droplet size about 2 μL, continuously tested ten times within a test time of not more than 60 s, and the average value was taken;

[0123] Stain resistance: draw a line about 5 cm long in the marked area with an oily marker pen, stand for 30 minutes, then wipe back and forth 10 times with a soft cloth with moderate force, observe the stain removal; dip the soft cloth in 1% neutral detergent solution, wring it out, then press a 500g weight on the cloth on the unremoved stain, wipe back and forth 20 times at a uniform speed, and observe the stain removal;

[0124] Adhesion: tested according to the standard GB / T 1720-2020 "Paint Film Circle Test".

[0125] Table 1 Test results of examples

[0126]

[0127] Table 2 Test results of comparative examples

[0128]

[0129] It can be seen from Table 1 that the water-based anti-staining metal baking paint prepared by the present application has excellent anti-staining and waterproof performance and good mechanical properties.

[0130] The above has exemplarily described the present application, it should be explained that, in the case of not departing from the core of the present application, any simple transformation, modification or other equivalent replacement which can not cost creative labor of the person skilled in the art, all fall into the protection scope of the present application.

Claims

1. A water-based antifouling metallic paint, characterized in that, It is prepared from the following parts by weight of raw materials: The composition includes: 48-60 parts acrylic resin, 6-10 parts fluorinated acrylic resin, 9-15 parts methyl etherified amino resin, 0.2-0.8 parts p-toluenesulfonic acid, 5-10 parts composite filler, 5-10 parts film-forming aid, 0.2-0.4 parts polyurethane thickener, 1-2 parts adhesion promoter, 0.3-0.5 parts pH adjuster, 0.3-0.8 parts wetting and leveling agent, 0.2-0.6 parts defoamer, and 10-15 parts water. The preparation method of the fluorinated modified acrylic resin includes the following steps: (1) Methyl methacrylate, 2-ethylhexyl acrylate, hydroxypropyl acrylate, methacrylic acid, vinyltriethoxysilane, N-ethylperfluorooctylsulfonamide ethyl acrylate, emulsifier and water are mixed evenly to obtain a pre-emulsion; (2) Mix ammonium persulfate with water until homogeneous to obtain an initiator aqueous solution; (3) Under an anaerobic atmosphere, mix part of the pre-emulsion, part of the initiator aqueous solution with water, and heat to carry out the first reaction; then add the remaining pre-emulsion and the remaining initiator aqueous solution dropwise simultaneously. After the addition is complete, carry out the second reaction. (4) Continue heating the reaction system from step (3) to react; after the reaction is complete, cool it, adjust the pH to 7.5-8.5, filter, and obtain fluorine-modified acrylic resin; The composite filler is prepared by mixing PTFE wax micro powder and zinc phosphate in a mass ratio of (1-2):1; The film-forming aid is prepared by mixing ethylene glycol monobutyl ether and diethylene glycol monobutyl ether at a mass ratio of 1:(1-3).

2. The water-based antifouling metallic paint according to claim 1, characterized in that, In step (1), the mass ratio of methyl methacrylate, 2-ethylhexyl acrylate, hydroxypropyl acrylate, methacrylic acid, vinyltriethoxysilane, N-ethylperfluorooctylsulfonamide ethyl acrylate, and emulsifier is (22-26):(12-15):(7-9):(2-4):(3-6):(10-14):(1.5-3).

3. The water-based antifouling metallic paint according to claim 1, characterized in that, In step (1), the mixing time is 30-45 minutes.

4. The water-based antifouling metallic paint according to claim 1, characterized in that, In step (2), the mass ratio of ammonium persulfate to water is 1:(25-30); the amount of ammonium persulfate used is 1.1%-1.2% of the total mass of methyl methacrylate, 2-ethylhexyl acrylate, hydroxypropyl acrylate, methacrylic acid, vinyltriethoxysilane and N-ethylperfluorooctylsulfonamide ethyl acrylate.

5. The water-based antifouling metallic paint according to claim 1, characterized in that, In step (3), the temperature of the first reaction is 80-85℃ and the time of the first reaction is 15-20 min; the time of the second reaction is 1.5-2.5 h.

6. The water-based antifouling metallic paint according to claim 1, characterized in that, In step (4), the reaction temperature is 90-95℃ and the reaction time is 1-2h.

7. A method for preparing a water-based antifouling metallic paint according to any one of claims 1-6, characterized in that, Includes the following steps: S1: Mix acrylic resin, fluorinated modified acrylic resin, film-forming aid and water evenly to obtain the first mixture; S2: Mix the first mixture, polyurethane thickener, adhesion promoter, pH adjuster, wetting and leveling agent and defoamer evenly to obtain the second mixture; S3: Mix the second mixture and the composite filler evenly to obtain the third mixture; S4: Mix the third mixture, methylated amino resin and p-toluenesulfonic acid evenly, filter, and obtain water-based antifouling metal paint.

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