High-temperature-resistant coating and preparation method thereof

Abstract

The invention discloses a high-temperature-resistant coating and a preparation method thereof, and belongs to the technical field of coatings. According to the technical scheme, the coating is characterized by comprising the following raw materials in parts by weight: 80-100 parts of acrylic modified polyester resin, 30-40 parts of epoxy modified organic silicon resin, 20-30 parts of aluminum paste, 15-20 parts of nano mica powder, 10-15 parts of low-melting-point glass powder, 3-7 parts of a curing agent, 0.1-0.2 part of a defoaming agent, 0.1-0.3 part of a wetting agent, 0.3-0.5 part of a thickening agent, 15-20 parts of water and 5-10 parts of ethanol. The problem of poor heat resistance of the water-based paint is solved.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and in particular to a high-temperature resistant coating and a preparation method thereof. Background Art

[0002] With the rapid development of modern industry and national defense construction (such as aerospace, aviation, weapons, etc.), the requirements for high-temperature resistant coatings of equipment are getting higher and higher. The paint film is required to not change color or fall off at high temperatures and still maintain good physical and mechanical properties and anti-corrosion properties.

[0003] High-temperature resistant coatings are widely used in high-temperature places such as steel chimneys, high-temperature pipelines, high-temperature furnace shells, oil cracking units, tanks, and artillery. They delay the thermal hydrogenation corrosion of metal equipment such as steel at high temperatures and ensure the long-term use of the equipment. Currently, the most commonly used high-temperature resistant coatings on the market are solvent-based coatings. During the production and use process, they release organic solvents into the environment, causing not only serious environmental pollution but also a huge waste of resources. With the increasing severity of environmental pollution, water-based coatings have become a research hotspot for low-volatile organic compound emission coatings that are of common concern to the world. However, the heat resistance of water-based coatings is inferior to that of solvent-based coatings, which limits their application range. Summary of the Invention

[0004] In order to solve the problem of poor heat resistance of water-based coatings, the present invention provides a high-temperature resistant coating and a preparation method thereof.

[0005] The first object of the present invention is to provide a high temperature resistant coating, which adopts the following technical solution: A high-temperature resistant coating comprises the following raw materials in parts by weight: 80-100 parts of acrylic modified polyester resin, 30-40 parts of epoxy modified silicone resin, 20-30 parts of aluminum-silver paste, 15-20 parts of nano-mica powder, 10-15 parts of low-melting-point glass powder, 3-7 parts of curing agent, 0.1-0.2 parts of defoaming agent, 0.1-0.3 parts of wetting agent, 0.3-0.5 parts of thickener, 15-20 parts of water, and 5-10 parts of ethanol.

[0006] In a preferred embodiment, the acrylic acid modified polyester resin comprises 85-95 parts, the epoxy modified silicone resin comprises 32-38 parts, the aluminum silver paste comprises 25-30 parts, the nano mica powder comprises 18-20 parts, the low melting point glass powder comprises 10-13 parts, the curing agent comprises 3-7 parts, the defoaming agent comprises 0.1-0.2 parts, the wetting agent comprises 0.1-0.3 parts, the thickener comprises 0.3-0.5 parts, the water comprises 15-20 parts, and the ethanol comprises 5-10 parts.

[0007] In a preferred embodiment, the acid value of the acrylic acid-modified polyester resin is 32-35 mgKOH / g.

[0008] In a preferred embodiment, the acrylic modified polyester resin is obtained by the following preparation method: neopentyl glycol and hexylene glycol are mixed, and then p-toluene dicarboxylic acid, acrylic prepolymer and catalyst are added at a temperature of 160±2°C, the temperature is raised to 250±5°C, and the temperature is kept until the resin is transparent. After cooling to 230±2°C, isophthalic acid is added and the reaction is kept warm for 2±0.5h to obtain the acrylic modified polyester resin.

[0009] In a preferred embodiment, the mass ratio of the neopentyl glycol, hexylene glycol, p-toluene dicarboxylic acid, acrylic prepolymer, and isophthalic acid is (4-7): (0.6-0.8): (6-9): (1.2-1.8): (1.1-1.4).

[0010] In a preferred embodiment, the aluminum-silver paste is stearic acid-coated aluminum-silver paste.

[0011] In a preferred embodiment, the melting temperature of the low-melting-point glass powder is 350°C.

[0012] The second aspect of the present invention is to provide a preparation method of the above-mentioned high-temperature resistant coating, comprising the following steps: stirring and mixing water, ethanol, acrylic modified polyester resin, and epoxy modified silicone resin, adding a wetting agent and mixing evenly, then adding aluminum silver paste, nano mica powder, and low-melting point glass powder and mixing evenly, and then adding a defoaming agent, a thickener, and a curing agent and mixing evenly to obtain a high-temperature resistant coating.

[0013] In summary, the present invention has the following beneficial effects: Acrylic modified polyester resin has good water solubility and film-forming properties. After the acrylic modified polyester resin and epoxy modified silicone resin are cured at high temperature, cross-linking reaction occurs between them to form a denser and more stable network structure, thereby improving the hardness of the coating and the adhesion between the coating and the substrate. In addition, the silicon-oxygen bonds in the epoxy modified silicone resin react with the acrylic modified polyester resin at high temperature to form a silicon-oxygen polymer network with higher heat resistance and chemical stability, thereby making the coating have better heat resistance, chemical corrosion resistance and mechanical strength.

[0014] Moreover, after adopting nano-mica powder in this application, the flaky structure of mica powder is conducive to releasing system stress in the coating, which can better solve the problem of coating cracking or peeling. Moreover, nano-mica powder has a small amount of hydroxyl groups on the surface. It can react with some functional groups of epoxy-modified silicone resin and acrylic acid-modified polyester resin in the coating preparation and high temperature environment, which can provide a certain reinforcement effect to the coating. Moreover, the addition of low-melting-point glass powder in the system can also increase the film-forming material to a certain extent, forming a glassy heat-resistant layer with the heat-resistant filler while melting, which helps to improve the high-temperature resistance of the coating. In addition, the flaky structure of nano-mica powder can not only improve the heat resistance of the coating, but also prevent or slow down the penetration of the medium into the substrate.

[0015] After the aluminum paste is coated with stearic acid, it not only makes the coating have a metallic effect, but also makes the aluminum paste stable and not easy to deform after being coated with stearic acid. Under high temperature conditions, the stearic acid coating shell cracks to expose the aluminum material, and the aluminum, metal matrix and Si-O-Si in the coating fuse to form a more stable silicate inorganic compound. The silicate inorganic compound has higher heat resistance and better substrate adhesion, thereby forming a complete heat-resistant structure from the bottom to the surface of the coating, improving the heat resistance of the coating. DETAILED DESCRIPTION

[0016] The present invention is further described in detail below with reference to the examples.

[0017] The raw materials used in this application are all commercially available.

[0018] Preparation Example 1 The preparation method of acrylic acid modified polyester resin comprises the following steps: S1. Preparation of acrylic prepolymer 3 g of methyl methacrylate, 2 g of styrene, 1 g of butyl acrylate, 0.3 g of acrylic acid, 0.18 g of di-tert-amyl peroxide, and 0.05 g of dodecyl mercaptan were mixed to obtain a monomer solution; 6 g of xylene was heated to 135° C. and nitrogen was passed through; the monomer mixture was added dropwise over 2 hours and then kept warm for 1.5 hours; then 0.02 g of di-tert-amyl peroxide was added and kept warm for 2 hours; the temperature was raised to 180° C., the solvent and unreacted monomers were removed by distillation under reduced pressure, and the temperature was lowered to obtain an acrylic acid prepolymer; S2. After mixing 4 g of neopentyl glycol and 0.6 g of hexanediol, 6 g of p-toluene dicarboxylic acid, 1.2 g of acrylic prepolymer and monobutyl tin oxide were added at a temperature of 160±2°C, the temperature was raised to 250±5°C, and the mixture was kept warm until the resin was transparent. After cooling to 230±2°C, 1.1 g of isophthalic acid was added and the mixture was kept warm for 2±0.5 h to obtain an acrylic modified polyester resin with an acid value of 32 mgKOH / g, that is, the mass ratio of neopentyl glycol, hexanediol, p-toluene dicarboxylic acid, acrylic prepolymer and isophthalic acid was 4:0.6:6:1.2:1.1.

[0019] Preparation Example 2 The preparation method of acrylic acid modified polyester resin comprises the following steps: S1. Preparation of acrylic prepolymer 3 g of methyl methacrylate, 2 g of styrene, 1 g of butyl acrylate, 0.3 g of acrylic acid, 0.18 g of di-tert-amyl peroxide, and 0.05 g of dodecyl mercaptan were mixed to obtain a monomer solution; 6 g of xylene was heated to 135° C. and nitrogen was passed through; the monomer mixture was added dropwise over 2 hours and then kept warm for 1.5 hours; then 0.02 g of di-tert-amyl peroxide was added and kept warm for 2 hours; the temperature was raised to 180° C., the solvent and unreacted monomers were removed by distillation under reduced pressure, and the temperature was lowered to obtain an acrylic acid prepolymer; S2. After mixing 5 g of neopentyl glycol and 0.7 g of hexanediol, 8 g of p-toluene dicarboxylic acid, 1.5 g of acrylic prepolymer and monobutyl tin oxide were added at a temperature of 160±2°C, the temperature was raised to 250±5°C, and the mixture was kept warm until the resin was transparent. After cooling to 230±2°C, 1.3 g of isophthalic acid was added and the mixture was kept warm for 2±0.5 h to obtain an acrylic modified polyester resin with an acid value of 33 mgKOH / g, that is, the mass ratio of neopentyl glycol, hexanediol, p-toluene dicarboxylic acid, acrylic prepolymer and isophthalic acid was 5:0.7:8:1.5:1.3.

[0020] Preparation Example 3 The preparation method of acrylic acid modified polyester resin comprises the following steps: S1. Preparation of acrylic prepolymer 3 g of methyl methacrylate, 2 g of styrene, 1 g of butyl acrylate, 0.3 g of acrylic acid, 0.18 g of di-tert-amyl peroxide, and 0.05 g of dodecyl mercaptan were mixed to obtain a monomer solution; 6 g of xylene was heated to 135° C. and nitrogen was passed through; the monomer mixture was added dropwise over 2 hours and then kept warm for 1.5 hours; then 0.02 g of di-tert-amyl peroxide was added and kept warm for 2 hours; the temperature was raised to 180° C., the solvent and unreacted monomers were removed by distillation under reduced pressure, and the temperature was lowered to obtain an acrylic acid prepolymer; S2. After mixing 7 g of neopentyl glycol and 0.8 g of hexanediol, 9 g of p-toluene dicarboxylic acid, 1.8 g of acrylic prepolymer and monobutyl tin oxide were added at a temperature of 160±2°C, the temperature was raised to 250±5°C, and the mixture was kept warm until the resin was transparent. After cooling to 230±2°C, 1.4 g of isophthalic acid was added and the mixture was kept warm for 2±0.5h to obtain an acrylic modified polyester resin with an acid value of 35 mgKOH / g, wherein the mass ratio of neopentyl glycol, hexanediol, p-toluene dicarboxylic acid, acrylic prepolymer and isophthalic acid is 7:0.8:9:1.8:1.4.

[0021] Example 1 A method for preparing a high-temperature resistant coating comprises the following steps: 1.5 g of water, 0.5 g of ethanol, 8 g of acrylic modified polyester resin obtained in Preparation Example 1, and 3 g of epoxy modified silicone resin are stirred and mixed, 0.01 g of sodium alkylbenzene sulfonate wetting agent is added and mixed evenly, 2 g of aluminum silver paste, 1.5 g of nano mica powder, and 1 g of low-melting point glass powder are added and mixed evenly, 0.01 g of polyether modified silicone defoamer, 0.03 g of PUR-50 are added and mixed evenly, and the mixture is stirred and mixed evenly. A polyurethane thickener and 0.3 g of a water-based epoxy curing agent were mixed to obtain a high-temperature resistant coating. The performance parameters of the epoxy-modified silicone resin were as follows: viscosity (coating-4 cups, 25°C, s) 15-40, solid content (150°C, 2h) 50±1, epoxy value (equivalent / 100g) 0.02-0.08, heat resistance 250°C, no bubbling or cracking for 200h, low-melting-point glass powder melting temperature of 350°C, and bulk density of 0.61 kg / m 3 .

[0022] Example 2 A method for preparing a high-temperature resistant coating comprises the following steps: 1.5 g of water, 0.5 g of ethanol, 8.5 g of acrylic acid-modified polyester resin obtained in Preparation Example 1, and 3.2 g of epoxy-modified silicone resin are stirred and mixed, 0.01 g of sodium alkylbenzene sulfonate wetting agent is added and mixed evenly, 2 g of aluminum silver paste, 1.5 g of nano-mica powder, and 1 g of low-melting-point glass powder are added and mixed evenly, 0.01 g of polyether-modified silicone defoamer, 0.03 g of PUR- 50g polyurethane thickener and 0.3g water-based epoxy curing agent were mixed to obtain a high-temperature resistant coating. The performance parameters of the epoxy-modified silicone resin were as follows: viscosity (coating-4 cups, 25°C, s) 15-40, solid content (150°C, 2h) 50±1, epoxy value (equivalent / 100g) 0.02-0.08, heat resistance 250°C, no bubbling or cracking for 200h, low melting point glass powder melting temperature of 350°C, bulk density of 0.61kg / m 3 .

[0023] Example 3 A preparation method of a high temperature resistant coating comprises the following steps: 1.5g of water, 0.5g of ethanol, 9g of acrylic modified polyester resin obtained in Preparation Example 1, and 3.5g of epoxy modified silicone resin are stirred and mixed, 0.01g of sodium alkylbenzene sulfonate wetting agent is added and mixed evenly, 2g of aluminum silver paste, 1.5g of nano mica powder, and 1g of low melting point glass powder are added and mixed evenly, 0.01g of polyether modified silicone defoamer, 0.03g of PUR-5 are added and mixed evenly, 0g polyurethane thickener and 0.3g water-based epoxy curing agent were mixed to obtain a high-temperature resistant coating. The performance parameters of the epoxy-modified silicone resin were as follows: viscosity (coating-4 cups, 25°C, s) 15-40, solid content (150°C, 2h) 50±1, epoxy value (equivalent / 100g) 0.02-0.08, heat resistance 250°C, no blistering or cracking for 200h, low-melting-point glass powder melting temperature of 350°C, bulk density 0.61kg / m 3 .

[0024] Example 4 A method for preparing a high-temperature resistant coating comprises the following steps: stirring and mixing 1.5 g of water, 0.5 g of ethanol, 9.5 g of acrylic acid-modified polyester resin obtained in Preparation Example 1, and 3.8 g of epoxy-modified silicone resin; adding 0.01 g of sodium alkylbenzene sulfonate wetting agent and mixing evenly; then adding 2 g of aluminum silver paste, 1.5 g of nano-mica powder, and 1 g of low-melting-point glass powder and mixing evenly; and then adding 0.01 g of polyether-modified silicone defoamer, 0.03 g of PUR- 50g polyurethane thickener and 0.3g water-based epoxy curing agent were mixed to obtain a high-temperature resistant coating. The performance parameters of the epoxy-modified silicone resin were as follows: viscosity (coating-4 cups, 25°C, s) 15-40, solid content (150°C, 2h) 50±1, epoxy value (equivalent / 100g) 0.02-0.08, heat resistance 250°C, no bubbling or cracking for 200h, low melting point glass powder melting temperature of 350°C, bulk density of 0.61kg / m 3 .

[0025] Example 5 A method for preparing a high-temperature resistant coating comprises the following steps: 1.5 g of water, 0.5 g of ethanol, 10 g of acrylic modified polyester resin obtained in Preparation Example 1, and 4 g of epoxy modified silicone resin are stirred and mixed, 0.01 g of sodium alkylbenzene sulfonate wetting agent is added and mixed evenly, 2 g of aluminum silver paste, 1.5 g of nano mica powder, and 1 g of low-melting point glass powder are added and mixed evenly, 0.01 g of polyether modified silicone defoamer, 0.03 g of PUR-50 are added and mixed evenly, A polyurethane thickener and 0.3 g of a water-based epoxy curing agent were mixed to obtain a high-temperature resistant coating. The performance parameters of the epoxy-modified silicone resin were as follows: viscosity (coating-4 cups, 25°C, s) 15-40, solid content (150°C, 2h) 50±1, epoxy value (equivalent / 100g) 0.02-0.08, heat resistance 250°C, no bubbling or cracking for 200h, low-melting-point glass powder melting temperature of 350°C, and bulk density of 0.61 kg / m 3 .

[0026] Example 6 A method for preparing a high-temperature resistant coating comprises the following steps: 1.5 g of water, 0.5 g of ethanol, 9 g of acrylic modified polyester resin obtained in Preparation Example 1, and 3.5 g of epoxy modified silicone resin are stirred and mixed, 0.01 g of sodium alkylbenzene sulfonate wetting agent is added and mixed evenly, 2.5 g of aluminum silver paste, 1.5 g of nano-mica powder, and 1 g of low-melting-point glass powder are added and mixed evenly, 0.01 g of polyether modified silicone defoamer, 0.03 g of PUR- 50g polyurethane thickener and 0.3g water-based epoxy curing agent were mixed to obtain a high-temperature resistant coating. The performance parameters of the epoxy-modified silicone resin were as follows: viscosity (coating-4 cups, 25°C, s) 15-40, solid content (150°C, 2h) 50±1, epoxy value (equivalent / 100g) 0.02-0.08, heat resistance 250°C, no bubbling or cracking for 200h, low melting point glass powder melting temperature of 350°C, bulk density of 0.61kg / m 3 .

[0027] Example 7 A preparation method of a high temperature resistant coating comprises the following steps: 1.5g of water, 0.5g of ethanol, 9g of acrylic modified polyester resin obtained in Preparation Example 1, and 3.5g of epoxy modified silicone resin are stirred and mixed, 0.01g of sodium alkylbenzene sulfonate wetting agent is added and mixed evenly, 3g of aluminum silver paste, 1.5g of nano mica powder, and 1g of low melting point glass powder are added and mixed evenly, 0.01g of polyether modified silicone defoamer, 0.03g of PUR-5 are added and mixed evenly, 0g polyurethane thickener and 0.3g water-based epoxy curing agent were mixed to obtain a high-temperature resistant coating. The performance parameters of the epoxy-modified silicone resin were as follows: viscosity (coating-4 cups, 25°C, s) 15-40, solid content (150°C, 2h) 50±1, epoxy value (equivalent / 100g) 0.02-0.08, heat resistance 250°C, no blistering or cracking for 200h, low-melting-point glass powder melting temperature of 350°C, bulk density 0.61kg / m 3 .

[0028] Example 8 A method for preparing a high-temperature resistant coating comprises the following steps: 1.5g of water, 0.5g of ethanol, 9g of acrylic modified polyester resin obtained in Preparation Example 1, and 3.5g of epoxy modified silicone resin are stirred and mixed, 0.01g of sodium alkylbenzene sulfonate wetting agent is added and mixed evenly, 2.5g of aluminum silver paste, 1.8g of nano mica powder, and 1.3g of low melting point glass powder are added and mixed evenly, 0.01g of polyether modified silicone defoamer, 0.03g of PUR are added, and the mixture is stirred and mixed evenly. -50 polyurethane thickener and 0.3g water-based epoxy curing agent were mixed to obtain a high-temperature resistant coating. The performance parameters of the epoxy-modified silicone resin were as follows: viscosity (coating-4 cup, 25℃, s) 15-40, solid content (150℃, 2h) 50±1, epoxy value (equivalent / 100g) 0.02-0.08, heat resistance 250℃, no bubbling or cracking for 200h, low melting point glass powder melting temperature of 350℃, bulk density of 0.61kg / m 3 .

[0029] Example 9 A method for preparing a high-temperature resistant coating comprises the following steps: stirring and mixing 1.5 g of water, 0.5 g of ethanol, 9 g of acrylic modified polyester resin obtained in Preparation Example 1, and 3.5 g of epoxy modified silicone resin, adding 0.01 g of sodium alkylbenzene sulfonate wetting agent and mixing evenly, then adding 2.5 g of aluminum silver paste, 2 g of nano-mica powder, and 1.5 g of low-melting-point glass powder and mixing evenly, and then adding 0.01 g of polyether modified silicone defoamer, 0.03 g of PUR- 50g polyurethane thickener and 0.3g water-based epoxy curing agent were mixed to obtain a high-temperature resistant coating. The performance parameters of the epoxy-modified silicone resin were as follows: viscosity (coating-4 cups, 25°C, s) 15-40, solid content (150°C, 2h) 50±1, epoxy value (equivalent / 100g) 0.02-0.08, heat resistance 250°C, no bubbling or cracking for 200h, low melting point glass powder melting temperature of 350°C, bulk density of 0.61kg / m 3 .

[0030] Example 10 A method for preparing a high-temperature resistant coating comprises the following steps: stirring and mixing 2g of water, 1g of ethanol, 9g of acrylic modified polyester resin obtained in Preparation Example 1, and 3.5g of epoxy modified silicone resin, adding 0.03g of sodium alkylbenzene sulfonate wetting agent and mixing evenly, then adding 2.5g of aluminum silver paste, 1.8g of nano-mica powder, and 1.3g of low-melting-point glass powder and mixing evenly, and then adding 0.02g of polyether modified silicone defoamer, 0.05g of PUR-5 0g polyurethane thickener and 0.7g water-based epoxy curing agent were mixed to obtain a high-temperature resistant coating. The performance parameters of the epoxy-modified silicone resin were as follows: viscosity (coating-4 cups, 25°C, s) 15-40, solid content (150°C, 2h) 50±1, epoxy value (equivalent / 100g) 0.02-0.08, heat resistance 250°C, no bubbling or cracking for 200h, low melting point glass powder melting temperature of 350°C, bulk density 0.61kg / m 3 .

[0031] Example 11 A method for preparing a high-temperature resistant coating is different from Example 8 in that the acrylic acid-modified polyester resin uses the acrylic acid-modified polyester resin of Preparation Example 2, and the rest are the same as Example 8.

[0032] Example 12 A method for preparing a high-temperature resistant coating is different from Example 8 in that the acrylic acid-modified polyester resin uses the acrylic acid-modified polyester resin of Preparation Example 3, and the rest are the same as Example 8.

[0033] Example 13 A method for preparing a high-temperature resistant coating, which is different from Example 11 in that the aluminum-silver paste is coated with stearic acid, specifically by mixing and grinding aluminum powder and stearic acid in a ratio of 2:1.

[0034] Example 14 A method for preparing a high-temperature resistant coating, which is different from Example 8 in that the low-melting-point glass powder has a melting temperature of 500°C and a bulk density of 0.77 kg / m 3 .

[0035] Comparative Example 1 A method for preparing a high-temperature resistant coating is different from Example 1 in that the raw materials lack low-melting-point glass powder, and the rest are the same as Example 1.

[0036] Comparative Example 2 A method for preparing a high-temperature resistant coating is different from that of Example 1 in that an equal amount of nano-wollastonite is used in place of nano-mica powder in the raw materials, and the rest are the same as those of Example 1.

[0037] Comparative Example 3 A method for preparing a high-temperature resistant coating is disclosed. The method differs from Example 1 in that the acrylic acid-modified polyester resin in the raw material is a commercially available acrylic acid-modified polyester resin. The properties of the commercially available acrylic acid-modified polyester resin are as follows: solid content 60±2%, viscosity (Brookfield viscometer 3# / 60 rpm / 25°C) 1100-1200 centipoise, and acid value 20-25 mgKOH / g. Other properties are the same as those in Example 1.

[0038] Comparative Example 4 A method for preparing a high-temperature resistant coating is different from Example 1 in that an equal amount of titanium dioxide is used instead of aluminum-silver paste, and the rest are the same as Example 1.

[0039] Performance testing The adhesion and high temperature performance of the high temperature coatings obtained in the above examples and comparative examples were tested, and the test results are shown in Table 1.

[0040] High temperature resistance: The test is conducted in accordance with the test method in GB / T1735-2009 "Determination of heat resistance of paints and varnishes". The coating thickness is 400μm, the substrate is steel plate, and the heating temperature is 500℃. The maximum time that the coating remains without falling off and cracking is measured.

[0041] Adhesion: The test was conducted in accordance with the determination method in GB / T9286-2021 "Paint and varnish cross-cut test", with a coating thickness of 400μm and a substrate of steel plate.

[0042] Salt spray resistance test: The test is carried out in accordance with the provisions of GB / T1771-91. The sample coated with high-temperature paint is placed in a salt spray machine and sprayed with 5wt% sodium chloride solution to observe whether the sample is bubbling or rusting.

[0043] Table 1 High temperature coating performance test results project High temperature resistance time of 500℃ / h Adhesion / Grade Salt spray resistance time / h Example 1 62 0 856 Example 2 64 0 862 Example 3 69 0 865 Example 4 68 0 863 Example 5 66 0 863 Example 6 70 0 895 Example 7 70 0 900 Example 8 82 0 912 Example 9 83 0 914 Example 10 83 0 915 Example 11 84 0 914 Example 12 85 0 915 Example 13 86 0 917 Example 14 77 0 906 Comparative Example 1 50 1 812 Comparative Example 2 57 1 841 Comparative Example 3 52 2 826 Comparative Example 4 54 0 839 As can be seen from Table 1: The high-temperature coatings obtained in Examples 1-5 of the present application can withstand a high temperature of 500°C for more than 60 hours, and have a salt spray resistance of more than 850 hours. This shows that when the content of other raw materials remains unchanged, the combination of acrylic modified polyester resin and epoxy modified silicone resin can effectively ensure the high-temperature resistance of the water-based coating and the bonding performance between the water-based coating and the substrate.

[0044] Compared with Example 3, Examples 6-7 can further improve the salt spray corrosion resistance of the water-based coating by adjusting the content of the aluminum-silver paste on the basis of Example 3. The reason is that the aluminum flakes in the aluminum-silver paste can form a dense metal layer on the coating, which helps to isolate the coating from the influence of the external environment, thereby improving the corrosion resistance of the coating.

[0045] Compared with Example 6, Examples 8-9 can effectively improve the high temperature resistance and salt spray corrosion resistance of the coating by changing the content of nano-mica powder and low-melting point glass powder on the basis of Example 6.

[0046] Compared with Example 11, when the aluminum-silver paste is coated with stearic acid, not only the high-temperature resistance of the coating can be improved, but also the salt spray corrosion resistance of the coating can be effectively guaranteed.

[0047] Compared with Example 8, when the melting temperature of the low-melting-point glass powder used in Example 14 is higher than the temperature specified in this application, the high-temperature resistance of the coating obtained in Example 14 is lower than that in Example 8. It can be seen that glass powder with a lower melting point can effectively improve the high-temperature resistance of the coating.

[0048] In Comparative Examples 1-4, when the raw materials lack low-melting point glass powder, or wollastonite is used instead of nano-mica powder, or commercially available acrylic modified polyester resin is used, or titanium dioxide is used instead of aluminum silver paste, the high temperature resistance and salt spray corrosion resistance of the coatings in Comparative Examples 1-4 are reduced. It can be seen that the combination of the raw materials in this application effectively improves the high temperature resistance and corrosion resistance of the water-based coating.

[0049] The embodiments of this specific implementation method are all preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, any equivalent changes made based on the structure, shape, and principle of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high temperature resistant coating, characterized in that: The invention comprises the following raw materials in parts by weight: 80-100 parts of acrylic modified polyester resin, 30-40 parts of epoxy modified silicone resin, 20-30 parts of aluminum silver paste, 15-20 parts of nano mica powder, 10-15 parts of low melting point glass powder, 3-7 parts of curing agent, 0.1-0.2 parts of defoaming agent, 0.1-0.3 parts of wetting agent, 0.3-0.5 parts of thickener, 15-20 parts of water and 5-10 parts of ethanol.

2. A high temperature resistant coating according to claim 1, characterized in that: In parts by weight, the acrylic modified polyester resin comprises 85-95 parts, the epoxy modified silicone resin comprises 32-38 parts, the aluminum silver paste comprises 25-30 parts, the nano mica powder comprises 18-20 parts, the low melting point glass powder comprises 10-13 parts, the curing agent comprises 3-7 parts, the defoaming agent comprises 0.1-0.2 parts, the wetting agent comprises 0.1-0.3 parts, the thickening agent comprises 0.3-0.5 parts, the water comprises 15-20 parts, and the ethanol comprises 5-10 parts.

3. A high temperature resistant coating according to claim 1 or 2, characterized in that: The acid value of the acrylic acid-modified polyester resin is 32-35 mgKOH / g.

4. A high temperature resistant coating according to claim 1 or 2, characterized in that: The acrylic modified polyester resin is obtained by the following preparation method: neopentyl glycol and hexylene glycol are mixed, and then p-toluene dicarboxylic acid, acrylic acid prepolymer and a catalyst are added at a temperature of 160±2° C., the temperature is raised to 250±5° C., and the temperature is kept until the resin is transparent, and then the temperature is lowered to 230±2° C., isophthalic acid is added, and the reaction is kept at the temperature for 2±0.5 hours to obtain the acrylic modified polyester resin.

5. A high temperature resistant coating according to claim 4, characterized in that: The mass ratio of the neopentyl glycol, hexylene glycol, p-toluene dicarboxylic acid, acrylic prepolymer and isophthalic acid is (4-7): (0.6-0.8): (6-9): (1.2-1.8): (1.1-1.4).

6. A high temperature resistant coating according to claim 1, characterized in that: The aluminum-silver paste is coated with stearic acid.

7. The high temperature resistant coating according to claim 1, characterized in that: The melting temperature of the low-melting-point glass powder is 350°C.

8. A method for preparing a high temperature resistant coating according to any one of claims 1 to 7, characterized in that: The method comprises the following steps: stirring and mixing water, ethanol, acrylic modified polyester resin and epoxy modified silicone resin, adding a wetting agent and mixing evenly, then adding aluminum silver paste, nano mica powder and low melting point glass powder and mixing evenly, and then adding a defoamer, a thickener and a curing agent and mixing evenly to obtain a high temperature resistant coating.