Normal-temperature-cured water-based high-temperature-resistant paint and preparation method thereof

Abstract

The present application relates to a kind of normal temperature cured water-based high temperature resistant paint and its preparation method, belong to high temperature resistant paint technical field.Normal temperature cured water-based high temperature resistant paint, including the following weight parts components: water-based silicone resin 40~45 parts;Siloxane modified wollastonite powder 3~5 parts;Aluminum silver paste 5~7 parts;Lithium carbonate 0.4~0.8 parts;Potassium silicate 0.2~0.3 parts;Lignin 0.1~0.3 parts;And water.Siloxane modified wollastonite powder has the effect of heat insulation, oxidation resistance, enhances matrix;Lithium carbonate and potassium silicate play the role of inhibiting oxidation, adjusting coating film system by thermal decomposition reaction;The thermal stability of lignin can resist calcination at high temperature;Aluminum silver paste plays the role of heat conduction performance, thermal radiation reflection and inhibiting surface reaction etc..Make the coating can keep stable under high temperature condition for a long time, and have more than 550 ℃ high temperature resistant limit.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of high-temperature-resistant coatings, and particularly relates to a normal-temperature-cured water-based high-temperature-resistant coating and a preparation method thereof. BACKGROUND

[0002] The information disclosed in this Background section is for the purpose of increasing the understanding of the background of the application without admitting that such information forms prior art that is already known to those skilled in the art.

[0003] Coating is a liquid or solid material coated on the surface of an object, which is used to provide protection, decoration, corrosion resistance and the like, and its main components include solvents, resins, fillers and the like. With the development of society, the demand for coatings in various fields has increased sharply. In some high-temperature environments, the ambient temperature of the coating is often high, and ordinary coatings often cannot withstand the thermal expansion, color change and other problems under such high-temperature environments. Therefore, high-temperature-resistant coatings gradually appear in everyone's field of vision.

[0004] High-temperature-resistant coatings generally refer to special functional coatings that can withstand temperatures above 300℃ for a long time, the paint film does not crack or fall off, and still has certain physical and chemical properties, so that the protected object can function normally in a high-temperature environment. It is generally composed of high-temperature-resistant resins, high-temperature-resistant fillers, solvents and additives. In order to meet the demand for the rapid development of modern equipment technology, high-temperature-resistant coatings for different temperatures and different fields are being developed. High-temperature-resistant coatings are divided into oven-cured and normal-temperature-cured types according to the curing mechanism.

[0005] Oven-cured types include pure organic silicon coatings, acrylic modified organic silicon coatings and the like, and the curing mechanism is that the silicon hydroxyl groups in the organic silicon resin condense to form silicon-oxygen-silicon bonds and release water molecules at high temperatures. Common organic silicon high-temperature-resistant coatings cannot be fully cured at room temperature and need to be cured at 150-230℃ for 0.5-1h to achieve their optimal performance. In actual application, when large-scale construction is carried out on large equipment and facilities, the construction site cannot be oven-cured. Because the paint film is not fully cured at room temperature after coating, its physical and mechanical properties, corrosion resistance and chemical resistance do not meet the requirements of full curing, and the paint film often fails prematurely in actual use.

[0006] Normal-temperature-cured coatings mainly include epoxy-modified organic silicon coatings and pre-hydrolyzate of ethyl silicate as high-temperature-resistant film-forming resin. For the existing normal-temperature-cured coatings, the inventors found that there are problems:

[0007] The pre-hydrolysate of ethyl silicate is used as a high-temperature resistant film-forming resin, and although the temperature resistance limit can reach 500 DEG C or above, the hydrolysis process of ethyl silicate is complex, resulting in a complicated preparation method of the high-temperature resistant film-forming resin, which is not conducive to actual production.

[0008] The preparation process of the epoxy-modified silicone coating is relatively simple, and the epoxy-modified silicone coating can be cured at room temperature, but the temperature resistance limit is generally about 400 DEG C; however, in the high-temperature smelting furnace, smelting equipment and heat treatment equipment in the metallurgical field, in the automobile engine and exhaust system, and in the combustion furnace and boiler in the power field, the temperature resistance limit of the coating is often required to be 450-500 DEG C or even higher. Obviously, in the above-mentioned fields, the epoxy-modified silicone coating is limited by the insufficient temperature resistance limit and cannot be applied.

[0009] In summary, it is necessary to provide a water-based high-temperature resistant coating which can be cured at room temperature and has a heat resistance limit higher than 500 DEG C and a simple preparation method. SUMMARY

[0010] To solve the above technical problems, the purpose of the present application is to provide a water-based high-temperature resistant coating which can be cured at room temperature and a preparation method thereof, and the temperature resistance limit of the coating is improved by adding components with heat insulation and antioxidant functions.

[0011] In order to achieve the above-mentioned purpose, the technical scheme of the present application is as follows:

[0012] In the first aspect, a water-based high-temperature resistant coating which can be cured at room temperature comprises the following components by weight:

[0013] 40-45 parts of water-based silicone resin;

[0014] 3-5 parts of siloxane-modified wollastonite powder;

[0015] 5-7 parts of aluminum silver paste;

[0016] 0.4-0.8 parts of lithium carbonate;

[0017] 0.2-0.3 parts of potassium silicate;

[0018] 0.1-0.3 parts of lignin;

[0019] and water.

[0020] Optionally, the weight fraction of water is 2-3 times that of the water-based silicone resin.

[0021] Optionally, the water-based silicone resin is one or more of acrylic silicone resin, polyether silicone resin, benzyl silicone resin and polyurethane silicone resin.

[0022] Preferably, the aqueous silicone resin is a polyether silicone resin and a phenylmethyl silicone resin compounded at a weight ratio of 3:1.

[0023] Optionally, the method for preparing the siloxane-modified wollastonite powder comprises:

[0024] The mixture of the siloxane and the wollastonite powder is placed in an ethanol solution, stirred uniformly and dried to obtain the siloxane-modified wollastonite powder.

[0025] The weight ratio of the siloxane and the wollastonite powder is 1:80-90.

[0026] Optionally, the siloxane is a siloxane monomer, which is methyl trimethoxysilane, methyl triethoxysilane, methyl triisopropoxysilane, ethyl trimethoxysilane, ethyl triethoxysilane, propyl trimethoxysilane, propyl triethoxysilane, phenyl trimethoxysilane or phenyl triethoxysilane.

[0027] Optionally, the average particle size of the wollastonite powder is 10-23 μm.

[0028] Optionally, the amount of the added ethanol is 90%-110% of the weight of the wollastonite powder.

[0029] Optionally, the specific stirring step comprises: controlling the rotation speed to be not higher than 60 r / min, stirring at 25-45 °C for 2.5-3.5 h.

[0030] Optionally, the drying method is air drying.

[0031] In the second aspect, the method for preparing the aqueous high-temperature-resistant paint that is cured at room temperature comprises the following steps:

[0032] S1, uniformly mixing the siloxane-modified wollastonite powder, lithium carbonate, potassium silicate and lignin, and grinding to a particle size of not higher than 25 μm to obtain dry materials;

[0033] S2, mixing the aqueous silicone resin, water and the dry materials obtained in S1, uniformly stirring at a low speed to obtain a mixture;

[0034] S3, adding all the aluminum paste into the mixture in multiple times, stirring and dispersing to prepare the aqueous high-temperature-resistant paint that is cured at room temperature.

[0035] Optionally, in S1, the rotation speed of the stirrer in the mixing step is 500-600 r / min.

[0036] Optionally, in S2, the silicone resin and the water are mixed and stirred uniformly before the dry materials are added.

[0037] Optionally, in S3, the total aluminum silver paste is divided into 20% of the total weight, 40% of the total weight and 40% of the total weight, first add 20% of the total weight of the aluminum silver paste into the mixture, after the first stirring and dispersion, add 40% of the total weight of the aluminum silver paste, after the second stirring and dispersion, add the remaining 40% of the total weight of the aluminum silver paste, and carry out the third stirring and dispersion.

[0038] Optionally, the first stirring and dispersion step includes: stirring machine speed 120-180 r / min, dispersion 10 min; the second stirring and dispersion step includes: stirring machine speed 140-200 r / min, dispersion 15 min; the third stirring and dispersion step includes: stirring machine speed 140-200 r / min, dispersion 15 min.

[0039] Optionally, the first stirring and dispersion is carried out at 40℃, and the second stirring and dispersion and the third stirring and dispersion are carried out at 55℃.

[0040] The third aspect is a coating layer prepared from the above-mentioned water-based high-temperature-resistant paint which is cured at room temperature, and the curing temperature is room temperature, and the temperature resistance limit is greater than 550℃.

[0041] The beneficial effects of the present application are:

[0042] 1. The water-based organic silicon resin used in the present application has a lower temperature resistance limit, and the temperature resistance limit of the unmodified organic silicon resin is below 350℃, and the temperature resistance limit of the epoxy-modified organic silicon resin can only reach 400℃. The present application adds siloxane-modified wollastonite powder in the components, which has the effects of heat insulation, oxidation resistance, and strengthening the matrix, improves the temperature resistance limit of the paint, and makes up for the defects of the existing organic silicon resin temperature resistance limit; lithium carbonate and potassium silicate improve the high-temperature resistance of the paint through the synergistic effects of thermal decomposition reaction, oxidation inhibition, structure stability enhancement, thermal decomposition inhibition, oxidation resistance, and coating film system adjustment; aluminum silver paste can effectively improve the high-temperature resistance of the paint through the synergistic effects of thermal conductivity, thermal radiation reflection, and surface reaction inhibition; at the same time, the thermal conductivity of aluminum silver particles can reduce the temperature of the coating surface, weaken the heat conduction, and thus improve the high-temperature resistance of the paint. Lignin can improve the high-temperature resistance of the paint through the synergistic effects of thermal stability, oxidation resistance, and matrix strengthening; the thermal stability of lignin can resist calcination at high temperature, improve the thermal stability and high-temperature resistance of the paint. At the same time, lignin can also resist oxidation, reduce the oxidation process on the surface of the paint, and improve the oxidation resistance of the paint. The addition of lithium carbonate and potassium silicate can form a stable heat absorption layer and an oxidation layer, reduce heat conduction, oxidation reaction and degradation, and cooperate with the remaining components to make the paint stable for a long time at high temperature and have a high-temperature resistance limit of more than 550℃.

[0043] 2. The waterborne silicone resin in this invention is selected from one or more of acrylic silicone resin, polyether silicone resin, benzyl silicone resin, and polyurethane silicone resin. All of the above-mentioned silicone resins possess good heat resistance, weather resistance, and stability, making them suitable as the main body of coatings. When the waterborne silicone resin is a mixture of polyether silicone resin and benzyl silicone resin in a weight ratio of 3:1, compared to using any one of the above silicone resins alone, it has the following advantages: polyether silicone resin has good high-temperature resistance, while benzyl silicone resin provides good abrasion resistance and chemical corrosion resistance. When the two are combined, the polyether silicone resin can enhance the high-temperature resistance of the coating and maintain the stability of the coating, while the benzyl silicone resin can provide additional abrasion resistance and chemical corrosion resistance, thereby enabling the coating to better resist thermal expansion in high-temperature environments and improving the durability of the high-temperature resistant resin.

[0044] 3. In the preparation method of this invention, the aluminum silver paste and the mixture are mixed stepwise, which allows for better control and adjustment of the dispersion of aluminum silver particles in the coating. Adding them gradually ensures that the aluminum particles are fully dispersed in the coating system, avoiding agglomeration, sedimentation, and accumulation, thus helping to maintain the uniformity, stability, and consistency of the coating. This also improves the dispersion of aluminum powder particles, fully utilizing their role in reducing heat transfer. Detailed Implementation

[0045] It should be noted that the following detailed descriptions are exemplary and intended to provide further illustration of the invention. Unless otherwise specified, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0046] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the scope of exemplary embodiments according to the invention. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0047] A water-based high-temperature resistant coating that cures at room temperature comprises the following components in parts by weight:

[0048] 40-45 parts of water-based silicone resin;

[0049] 3-5 parts of siloxane-modified wollastonite powder;

[0050] 5-7 parts aluminum silver paste;

[0051] Lithium carbonate 0.4–0.8 parts;

[0052] Potassium silicate 0.2-0.3 parts;

[0053] Lignin 0.1-0.3 parts;

[0054] and water.

[0055] Optionally, the weight fraction of water is 2-3 times that of the aqueous silicone resin.

[0056] Optionally, the aqueous silicone resin is one or more of an acrylic silicone resin, a polyether silicone resin, a benzyl silicone resin, and a polyurethane silicone resin.

[0057] Preferably, the aqueous silicone resin is a polyether silicone resin and a benzyl silicone resin compounded at a weight ratio of 3:1.

[0058] The aqueous silicone resin has a special chemical structure: the organic group and the inorganic silicic acid chain are connected through the formation of a siloxane bond to form a three-dimensional network structure, which gives the silicone resin high heat resistance.

[0059] The aqueous silicone resin forms the matrix of the ambient-cured aqueous high-temperature-resistant coating.

[0060] Optionally, the preparation method of the siloxane-modified wollastonite powder comprises:

[0061] The mixture of siloxane and wollastonite powder is placed in an ethanol solution, stirred uniformly and dried to obtain the siloxane-modified wollastonite powder.

[0062] The weight ratio of siloxane to wollastonite powder is 1:80-90.

[0063] The siloxane-modified wollastonite powder has the following effects:

[0064] ①Thermal insulation effect; wollastonite powder is an inorganic material with low thermal conductivity. After siloxane modification, a layer of siloxane film is formed on the surface of wollastonite, which can slow down heat conduction and form a stable thermal insulation layer at high temperature. After adding the siloxane-modified wollastonite powder to the coating, the conduction of heat is reduced, thereby reducing the surface temperature of the coating and improving the high-temperature resistance.

[0065] ②Antioxidant effect; the siloxane film on the surface of the siloxane-modified wollastonite powder can play a certain oxidation protection role. At high temperature, the surface of the coating is prone to oxidation reaction, forming oxidation products and causing the performance of the coating to decline. The presence of the siloxane film can block the entry of oxygen and reduce the oxidation rate of the coating, thereby improving the antioxidant performance of the coating and prolonging the service life of the coating.

[0066] ③Strengthen the matrix; wollastonite powder can be used as a filler, increase the solid content of the coating, strengthen the matrix structure. The addition of fillers can increase the hardness, strength and wear resistance of the coating, making the coating more hard and durable. This is particularly important for coatings in high temperature environments, which can improve the high temperature resistance of the coating.

[0067] Optionally, the siloxane is a siloxane monomer, which is methyl trimethoxysilane, methyl triethoxysilane, methyl triisopropoxysilane, ethyl trimethoxysilane, ethyl triethoxysilane, propyl trimethoxysilane, propyl triethoxysilane, phenyl trimethoxysilane or phenyl triethoxysilane.

[0068] Optionally, the average particle size of the wollastonite powder is 10-23 μm, so that it is uniform with the particle size of other dry materials in the grinding.

[0069] Optionally, the amount of ethanol added is 90%-110% of the weight of the wollastonite powder; the role of ethanol is to wet the wollastonite powder and promote the full contact of siloxane with the wollastonite powder.

[0070] Preferably, the added weight of ethanol is the same as the weight of the wollastonite powder.

[0071] Optionally, the specific stirring step includes controlling the rotation speed not higher than 60 r / min, stirring at 25-45℃ for 2.5-3.5 h.

[0072] Optionally, the drying method is air drying.

[0073] The addition of lithium carbonate in the coating can have the following effects:

[0074] ①Thermal decomposition reaction: lithium carbonate will undergo thermal decomposition reaction at high temperature, producing carbon dioxide and lithium oxide, absorbing a large amount of heat, forming a heat absorption layer, effectively reducing the surface temperature of the coating, slowing down heat conduction, and improving the high temperature resistance;

[0075] ②Inhibition of oxidation: lithium carbonate will produce lithium oxide at high temperature, which can combine with oxygen in the coating to form a stable oxidation layer, preventing further erosion of the coating and improving the high temperature resistance of the coating;

[0076] ③Strengthen the structural stability: lithium carbonate can increase the solid content of the coating, enhance the structural stability and wear resistance of the coating.

[0077] The addition of potassium silicate in the coating can have the following effects:

[0078] ① Thermal decomposition inhibition: Potassium silicate can inhibit the thermal decomposition reaction of other components in the coating at high temperature, prevent the generation of decomposition products, reduce the release of heat and heat conduction, maintain the stability of the coating, and improve the high temperature resistance;

[0079] ② Anti-oxidation performance: Potassium silicate can form potassium oxide and react with free radicals in the organic components in the coating, thereby reducing the oxidation reaction of the coating, preventing the oxidation and degradation of the coating by inhibiting the entry of oxygen, and improving the anti-oxidation performance and high temperature resistance of the coating.

[0080] The addition of aluminum silver paste in the coating can have the following effects:

[0081] ① Thermal conductivity: The metal aluminum in the aluminum silver paste has high thermal conductivity. After adding the aluminum silver paste in the coating, the metal particles in the coating can increase the thermal conductivity of the coating surface, effectively absorb and disperse the heat inside the coating, reduce heat conduction, thereby reducing the surface temperature of the coating and improving the high temperature resistance of the coating;

[0082] ② Thermal radiation reflection: Aluminum in the aluminum silver paste has good thermal radiation reflection performance. At high temperatures, the coating surface will be irradiated by thermal radiation, causing the surface temperature to rise. The aluminum particles can reflect part of the thermal radiation, reducing the rise in surface temperature of the coating and improving the high temperature resistance of the coating;

[0083] ③ Surface reaction inhibition: The presence of aluminum silver paste can also inhibit the oxidation reaction on the surface of the coating. The metal aluminum particles can absorb oxygen and form an oxide layer to prevent oxidation, thereby reducing the generation of oxidation products, reducing the oxidation rate of the coating, and improving the anti-oxidation performance and high temperature resistance of the coating.

[0084] Lignin can improve the high temperature resistance of the coating through the synergistic effect of thermal stability, anti-oxidation performance and matrix enhancement:

[0085] The thermal stability of lignin can resist calcination at high temperatures, improve the thermal stability and high temperature resistance of the coating. At the same time, lignin can also resist oxidation, reduce the oxidation process on the surface of the coating, and improve the anti-oxidation performance of the coating.

[0086] Although water-based silicone resin is limited by its own low temperature limit, even if the epoxy modified silicone resin can only reach a temperature limit of 400℃, and the unmodified silicone resin has a temperature limit below 350℃, but through the synergistic cooperation with the remaining components, the coating can remain stable for a long time under high temperature conditions, and has a high temperature resistance limit of more than 550℃.

[0087] The preparation method of the above-mentioned normal temperature curing water-based high temperature resistant coating comprises the following steps:

[0088] S1, mixing siloxane modified wollastonite powder, lithium carbonate, potassium silicate and lignin uniformly, and grinding to a particle size of no more than 25 μm to obtain dry materials;

[0089] S2, mixing the water-based silicone resin, water and the dry materials obtained in S1 uniformly at low speed to obtain a mixture;

[0090] S3, dividing the total aluminum paste into three parts of 20% of the total aluminum paste weight, 40% of the total aluminum paste weight and 40% of the total aluminum paste weight, adding 20% of the total aluminum paste weight of the aluminum paste to the mixture, stirring and dispersing for the first time, then adding 40% of the total aluminum paste weight of the aluminum paste, stirring and dispersing for the second time, then adding the remaining 40% of the total aluminum paste weight of the aluminum paste, stirring and dispersing for the third time to obtain a water-based high-temperature resistant paint that can be cured at room temperature.

[0091] Optionally, in S1, the stirring speed in the mixing step is 500-600 r / min.

[0092] Optionally, in S2, the silicone resin and water are mixed, and the dry materials are added after sufficient mixing.

[0093] Optionally, in S3, the first stirring and dispersing step includes stirring at a speed of 120-180 r / min for 10 min, the second stirring and dispersing step includes stirring at a speed of 140-200 r / min for 15 min, and the third stirring and dispersing step includes stirring at a speed of 140-200 r / min for 15 min.

[0094] Optionally, the first stirring and dispersing is carried out at 40°C, and the second stirring and dispersing and the third stirring and dispersing are carried out at 55°C.

[0095] (This is because after adding the aluminum paste, the viscosity of the mixture increases, so the stirring and dispersing temperature needs to be increased, and the aluminum paste needs to be added multiple times to promote the dispersion of aluminum in the aluminum paste.)

[0096] The coating layer prepared from the above-mentioned water-based high-temperature resistant paint that can be cured at room temperature has a temperature resistance limit of greater than 550°C.

[0097] Optionally, the coating layer is applied by spraying or brushing,

[0098] Optionally, the paint film thickness is 0.1 mm.

[0099] In order to further illustrate the present application, the following examples are provided for detailed description, wherein the aluminum paste is a water-based aluminum paste HC series, which is commercially available from ManTech Nano Technology Co., Ltd., and is a commercially available product;

[0100] The wollastonite powder is a commercially available product, and the main component is calcium carbonate.

[0101] I. Preparation Example of Siloxane Modified Wollastonite Powder

[0102] Preparation Example 1

[0103] Take 10 g of methyl trimethoxysilane, 800 g of wollastonite powder with a particle size of 20 μm, mix the two, and place them in 800 g of ethanol, control the rotation speed at 60 r / min, stir at 25 °C for 2.5 h, and after air drying, obtain the siloxane modified wollastonite powder.

[0104] Preparation Example 2

[0105] Take 10 g of methyl trimethoxysilane, 850 g of wollastonite powder with a particle size of 20 μm, mix the two, and place them in 850 g of ethanol, control the rotation speed at 50 r / min, stir at 38 °C for 3 h, and after air drying, obtain the siloxane modified wollastonite powder.

[0106] Preparation Example 3

[0107] Take 10 g of methyl trimethoxysilane, 900 g of wollastonite powder with a particle size of 20 μm, mix the two, and place them in 900 g of ethanol, control the rotation speed at 45 r / min, stir at 45 °C for 3.5 h, and after air drying, obtain the siloxane modified wollastonite powder.

[0108] The siloxane modified wollastonite powders obtained in Preparation Examples 1-3 have the same properties and can be used for the preparation of room temperature cured waterborne high temperature resistant coatings, obtaining the same effect.

[0109] II. Embodiment of Room Temperature Cured Waterborne High Temperature Resistant Coatings

[0110] Embodiment 1

[0111] S1, take 30 g of siloxane modified wollastonite powder, 4 g of lithium carbonate, 2 g of potassium silicate, and 1 g of lignin, mix them well at 500 r / min, and grind to a particle size of not more than 25 μm to obtain dry materials;

[0112] The siloxane modified wollastonite powder is obtained from Preparation Example 1;

[0113] S2, take 400 g of waterborne silicone resin and 1200 g of water, mix them with the obtained dry materials, and stir at 40 r / min for 20 min to obtain a mixture;

[0114] The waterborne silicone resin is selected as an acrylic silicone resin with a solid content of 52 wt%;

[0115] S3, heating the obtained mixture to 40℃ in a water bath, then adding 12g of aluminum silver paste at 40℃ into the mixture, dispersing at 140r / min for 10min; increasing the heating temperature of the water bath to 55℃, adding 24g of aluminum silver paste at 55℃, dispersing at 160r / min for 15min; controlling the temperature unchanged, adding the last 24g of aluminum silver paste at 55℃, dispersing at 140-200r / min for 15min, to obtain a water-based high-temperature resistant paint that is cured at room temperature;

[0116] Among them, a total of 50g of aluminum silver paste is added.

[0117] Example 2

[0118] S1, weighing 42g of siloxane modified wollastonite powder, 5g of lithium carbonate, 2.4g of potassium silicate and 2.1g of lignin, mixing well at 550r / min, and grinding to a particle size of not more than 25μm to obtain a dry material;

[0119] Among them, the siloxane modified wollastonite powder is obtained from Preparation Example 2;

[0120] S2, weighing 430g of water-based silicone resin and 1030g of water, mixing with the obtained dry material, and stirring at 40r / min for 20min to obtain a mixture;

[0121] Among them, the water-based silicone resin is obtained by compounding 50wt% solid content of polyether silicone resin and 50wt% solid content of benzyl silicone resin at a weight ratio of 3:1;

[0122] S3, heating the obtained mixture to 40℃ in a water bath, then adding 12g of aluminum silver paste at 40℃ into the mixture, dispersing at 140r / min for 10min; increasing the heating temperature of the water bath to 55℃, adding 24g of aluminum silver paste at 55℃, dispersing at 160r / min for 15min; controlling the temperature unchanged, adding the last 24g of aluminum silver paste at 55℃, dispersing at 140-200r / min for 15min, to obtain a water-based high-temperature resistant paint that is cured at room temperature;

[0123] Among them, a total of 60g of aluminum silver paste is added.

[0124] Example 3

[0125] S1, weighing 50g of siloxane modified wollastonite powder, 8g of lithium carbonate, 3g of potassium silicate and 3g of lignin, mixing well at 600r / min, and grinding to a particle size of not more than 25μm to obtain a dry material;

[0126] Among them, the siloxane modified wollastonite powder is obtained from Preparation Example 3;

[0127] S2, weigh 450 g of the aqueous silicone resin and 900 g of water, mix with the obtained dry materials, and stir mix at 60 r / min for 40 min to obtain a mixture;

[0128] The aqueous silicone resin is obtained by compounding a polyether silicone resin with a solid content of 48 wt% and an acrylic silicone resin with a solid content of 50 wt% at a weight ratio of 1:1.

[0129] S3, heat the obtained mixture to 40℃ in a water bath, then add 14 g of aluminum silver paste at 40℃ to the mixture, and disperse at 180 r / min for 10 min; increase the heating temperature of the water bath to 55℃, add 28 g of aluminum silver paste at 55℃, and disperse at 200 r / min for 15 min; control the temperature unchanged, add the last 28 g of aluminum silver paste at 55℃, and disperse at 200 r / min for 15 min, to obtain the room temperature curing aqueous high temperature resistant coating;

[0130] The total amount of aluminum silver paste added is 70 g.

[0131] III. Comparative Example of the Room Temperature Curing Aqueous High Temperature Resistant Coating

[0132] Comparative Example 1

[0133] This comparative example is compared with Example 1, the difference being that the wollastonite powder in the components is not siloxane modified.

[0134] Comparative Example 2

[0135] This comparative example is compared with Example 1, the difference being that no siloxane modified wollastonite powder is added.

[0136] Comparative Example 3

[0137] This comparative example is compared with Example 1, the difference being that no aluminum silver paste is added; and the preparation method does not include the process of adding aluminum silver paste in steps.

[0138] Comparative Example 4

[0139] This comparative example is compared with Example 1, the difference being that no lithium carbonate is added.

[0140] Comparative Example 5

[0141] This comparative example is compared with Example 1, the difference being that no potassium silicate is added.

[0142] Comparative Example 6

[0143] This comparative example is compared with Example 1, the difference being that no lignin is added.

[0144] Performance Test

[0145] Performance test was carried out on the above examples and comparative examples.

[0146] Heat resistance detection: according to the requirements of standard GB / T 735-2009 "Paint film heat resistance determination method", the cured test piece was put into the muffle furnace, the temperature was programmed to the test temperature and kept constant for 3h, then the test piece was taken out after cooling to room temperature, and the surface condition of the coating was observed.

[0147] Drying time: the test of surface drying time and real drying time of the paint was carried out according to standard / T 1728-2020 "Paint film, putty drying time determination method".

[0148] Adhesion: the adhesion of the coating after curing for 7d was tested according to standard GB / T 5210-2006 "Color paint and varnish pull-off method adhesion test", and the dry film thickness of the coating was 100μm.

[0149] The test results are shown in Table 1.

[0150] Table 1

[0151]

[0152]

[0153] It can be seen that the paint prepared in examples 1-3 has good temperature resistance limit, which is above 550℃, and has relatively short surface drying time and real drying time, and the adhesion is also above 5MPa.

[0154] The paint prepared in comparative examples 1-6 lacks any one component, and cannot achieve the effect of resisting 550℃, compared with example 1.

[0155] The water-based silicone resin of example 2 is a polyether silicone resin compounded with a benzyl silicone resin at a weight ratio of 3:1. Compared with the use of any of the above silicone resins alone, it has the following advantages: the polyether silicone resin has good high temperature resistance, and the benzyl silicone resin can provide good wear resistance and chemical corrosion resistance. When the two are compounded, the polyether silicone resin can enhance the high temperature resistance of the paint and maintain the stability of the coating, and the benzyl silicone resin can provide additional wear resistance and chemical corrosion resistance, so that the paint can better resist thermal expansion in high temperature environment.

[0156] The above only describes the preferred embodiments of the present application and is not intended to limit the present application. For those skilled in the art, the present application can have various modifications and changes. Any modification, equivalent replacement, improvement, etc. made within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A water-based high-temperature resistant coating that cures at room temperature, characterized in that, The components include the following parts by weight: 40-45 parts of water-based organosilicon resin; 3-5 parts of siloxane-modified wollastonite powder; 5-7 parts aluminum silver paste; Lithium carbonate 0.4~0.8 parts; Potassium silicate 0.2~0.3 parts; Lignin 0.1~0.3 parts; and water; The waterborne silicone resin is one or more of acrylic silicone resin, polyether silicone resin, benzyl silicone resin, and polyurethane silicone resin.

2. The room-temperature curing water-based high-temperature resistant coating as described in claim 1, characterized in that, The waterborne silicone resin is obtained by compounding polyether silicone resin and benzyl silicone resin in a weight ratio of 3:

1.

3. The water-based high-temperature resistant coating that cures at room temperature as described in claim 1, characterized in that, The water-based silicone resin is obtained by compounding polyether silicone resin and acrylic silicone resin in a weight ratio of 1:

1.

4. The water-based high-temperature resistant coating that cures at room temperature as described in claim 1, characterized in that, The water is 2 to 3 times the weight of the water-based silicone resin.

5. The room-temperature curing water-based high-temperature resistant coating as described in claim 1, characterized in that, The preparation method of the siloxane-modified wollastonite powder includes: A mixture of siloxane and wollastonite powder is placed in an ethanol solution, stirred until homogeneous, and then dried to obtain siloxane-modified wollastonite powder.

6. The room-temperature curing water-based high-temperature resistant coating as described in claim 5, characterized in that, The weight ratio of siloxane to wollastonite powder is 1:80~90; The siloxane is a siloxane monomer, specifically: methyltrimethoxysiloxane, methyltriethoxysiloxane, methyltriisopropoxysiloxane, ethyltrimethoxysiloxane, ethyltriethoxysiloxane, propyltrimethoxysiloxane, propyltriethoxysiloxane, phenyltrimethoxysiloxane, or phenyltriethoxysiloxane.

7. The room-temperature curing water-based high-temperature resistant coating as described in claim 5, characterized in that, The average particle size of the wollastonite powder is 10~23μm. The amount of ethanol added is 90% to 110% of the weight of wollastonite powder; The drying method is air drying.

8. A method for preparing a room-temperature curing, high-temperature resistant water-based coating as described in any one of claims 1-7, characterized in that, Includes the following steps: S1. Mix siloxane-modified wollastonite powder, lithium carbonate, potassium silicate and lignin evenly, and grind to a particle size of no more than 25μm to obtain dry material; S2. Mix the water-based silicone resin, water and the dry material obtained in S1, and stir at low speed until uniform to obtain a mixture; S3. Add all the aluminum silver paste to the mixture in multiple batches, stir and disperse to obtain a water-based high-temperature resistant coating that cures at room temperature.

9. The preparation method of the room-temperature curing waterborne high-temperature resistant coating as described in claim 8, characterized in that, In S2, water-based silicone resin and water are mixed and stirred evenly before adding dry materials.

10. The method for preparing a room-temperature curing waterborne high-temperature resistant coating as described in claim 8, characterized in that, In S3, all aluminum silver paste is divided into 20%, 40%, and 40% by weight of total weight. First, 20% of the total weight of aluminum silver paste is added to the mixture. After the first stirring and dispersion, 40% of the total weight of aluminum silver paste is added. After the second stirring and dispersion, the remaining 40% of the total weight of aluminum silver paste is added and stirred and dispersed for a third time. The first mixing and dispersion step includes: mixing speed of 120~180 r / min, dispersion for 10 min; the second mixing and dispersion step includes: mixing speed of 140~200 r / min, dispersion for 15 min; the third mixing and dispersion step includes: mixing speed of 140~200 r / min, dispersion for 15 min. The first stirring and dispersion was carried out at 40°C, and the second and third stirring and dispersion were carried out at 55°C.

11. A coating formed by a room-temperature curing waterborne high-temperature resistant coating as described in any one of claims 1-7, or a coating formed by a coating prepared by the method for preparing a room-temperature curing waterborne high-temperature resistant coating as described in any one of claims 8-10, characterized in that, The curing temperature is room temperature, and the temperature resistance limit is greater than 550℃.

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