A water-based single-component inorganic anticorrosive paint and a method for preparing the same

Abstract

The application discloses a kind of water-based single-component inorganic anticorrosive paint and preparation method thereof, belong to anticorrosive paint technical field, its technical scheme main point is a kind of water-based single-component inorganic anticorrosive paint, including the following weight parts of raw materials: silane modified potassium silicate emulsion 6-10 parts, water-based acrylic emulsion 18-25 parts, micro-nano filler 25-35 parts, thickening agent 1.6-2.5 parts, isopropanol 2.5-3 parts, dipropylene glycol butyl ether 2-3 parts, triethylamine 0.8-1.2 parts, other auxiliary agent 1.7-2.6 parts, water 24-29 parts, by silane modification treatment to potassium silicate improve its compatibility between water-based acrylic emulsion, construct interpenetrating network structure, the addition of micro-nano filler, make the network structure after solidification more compact, improve the weather resistance of coating.

Description

Technical Field

[0001] This invention relates to the field of anti-corrosion coatings, and in particular to a water-based single-component inorganic anti-corrosion coating and its preparation method. Background Technology

[0002] In the field of metal surface protection, anti-corrosion coatings have always been a crucial research area. With continuous industrial development, the demand for protection of metal materials is increasing daily, and the performance and quality of anti-corrosion coatings directly affect the service life and safety of metal products. Anti-corrosion coatings have a wide range of applications, covering numerous fields such as construction, machinery, chemicals, and transportation. Their development is of great significance for improving the protective effect of metal materials, reducing maintenance costs, and minimizing resource waste. Different types of anti-corrosion coatings have their own advantages and disadvantages in the market, driving the entire industry to continuously explore higher-quality products.

[0003] Currently, in the field of metal surface corrosion protection, common coating types are mainly divided into organic and inorganic anti-corrosion coatings. Organic anti-corrosion coatings are widely used in various scenarios due to their excellent performance in flexibility, adhesion, and decorative properties. Inorganic anti-corrosion coatings, on the other hand, use inorganic binders, such as silicates, phosphates, and silica sols, as film-forming substances and water as the dispersion medium. Among them, inorganic silicate coatings with silicate as the film-forming matrix have become a research hotspot due to their advantages such as low pollution, heat resistance, corrosion resistance, resistance to fading, and low cost. Both types of coatings play their respective roles in different environments and under different requirements.

[0004] However, existing inorganic silicate coatings have significant drawbacks. Because their drying and film formation involves chemical cross-linking and curing, the shrinkage stress is substantial, resulting in insufficient coating flexibility. This makes the coating prone to cracking or peeling, and these cracks become channels for moisture, oxygen, and corrosive media to penetrate, thus significantly reducing the weather resistance and corrosion resistance of inorganic silicate anti-corrosion coatings. Summary of the Invention

[0005] To address the problems in the prior art, this invention provides a water-based single-component inorganic anti-corrosion coating and its preparation method. By modifying potassium silicate with silane, its compatibility with water-based acrylic emulsion is improved, an interpenetrating network structure is constructed, and the addition of micro- and nano-scale fillers makes the cured network structure more compact, thereby improving the weather resistance of the coating.

[0006] The first aspect of this invention is to provide a water-based, single-component inorganic anti-corrosion coating, which adopts the following technical solution:

[0007] A water-based, single-component inorganic anti-corrosion coating comprises the following raw materials in parts by weight: 6-10 parts of silane-modified potassium silicate emulsion, 18-25 parts of water-based acrylic emulsion, 25-35 parts of micro / nano-grade filler, 1.6-2.5 parts of thickener, 2.5-3 parts of isopropanol, 2-3 parts of dipropylene glycol butyl ether, 0.8-1.2 parts of triethylamine, 1.7-2.6 parts of other additives, and 24-29 parts of water.

[0008] By adopting the above technical solution, the silane coupling agent in the silane-modified potassium silicate emulsion possesses a unique molecular structure. One end can chemically bond with potassium silicate, while the other end can interact with groups in the aqueous acrylic emulsion, thereby improving the compatibility between the silane-modified potassium silicate emulsion and the aqueous acrylic emulsion. The molecular chains of both interpenetrate, constructing an interpenetrating network structure, which increases the contact area and strengthens the adhesion between the cured coating and the substrate, thus improving the coating's adhesion. The interpenetrating network structure formed by the silane-modified potassium silicate emulsion and the aqueous acrylic emulsion serves as a basic framework, with micro / nano-scale fillers dispersed within it. These micro / nano-scale fillers have small particle sizes and large specific surface areas, filling the voids in the interpenetrating network and intertwining with it to form a multi-level dense network structure. This multi-level dense network structure effectively blocks the penetration of moisture, oxygen, and corrosive media, reducing the erosion of the coating by the external environment and improving the coating's weather resistance.

[0009] Isopropanol has a low freezing point, which can lower the freezing point of the coating system. Dipropylene glycol butyl ether has good solvent properties and evaporation rate. When used together, the two can maintain the fluidity and dispersibility of the coating at low temperatures, allowing the coating to be applied normally.

[0010] In a preferred embodiment, the silane-modified potassium silicate emulsion is obtained by the following preparation method:

[0011] S1. Add nano-silica sol to potassium silicate solution, control the pH at 9-10, and stir the reaction at 40-50℃ for 30-35 minutes to obtain a mixture;

[0012] S2. Add the silane coupling agent to a mixed solvent of ethanol and water and hydrolyze it to form a silane hydrolysate;

[0013] S3. Add the silane hydrolysate to the mixture from step S1 and react at 50-60℃ for 1-2 hours to obtain a silane-modified potassium silicate emulsion.

[0014] By employing the above technical solution, potassium silicate solution is modified simultaneously using nano-silica sol and silane coupling agents. Nano-silica sol improves the stability and dispersibility of the system, and after potassium silicate curing, nano-silica fills the microporous structure of the cured potassium silicate, increasing coating density and blocking water and oxygen penetration. Silane coupling agents enhance the bonding force between the potassium silicate emulsion and other components, giving the emulsion better water resistance and adhesion. Simultaneously, when the modified silane-modified potassium silicate emulsion is mixed with water-based acrylic emulsion, a good synergistic effect is formed, further improving the coating's flexibility and reducing coating cracking or peeling caused by shrinkage stress, thereby improving the coating's weather resistance and corrosion resistance.

[0015] In a preferred embodiment, the amount of the nano-silica sol is 40-50% of the solid content of the potassium silicate solution, and the amount of the silane coupling agent is 20-25% of the solid content of the potassium silicate solution.

[0016] In a preferred embodiment, the silane coupling agent is composed of KH-560 and methyltrimethoxysilane in a weight ratio of (3-4):(6-7).

[0017] By adopting the above technical solution, KH-560 contains epoxy groups, which can react with the hydroxyl groups in potassium silicate to enhance the crosslinking degree of potassium silicate. Simultaneously, its epoxy groups can also react with carboxyl groups and other groups in waterborne acrylic emulsions, improving the compatibility and bonding force between the emulsions. Methyltrimethoxysilane, after hydrolysis, can form a siloxane structure, which connects with the siloxane bonds in potassium silicate and the waterborne acrylic emulsion. Furthermore, methyltrimethoxysilane can regulate the crosslinking density of the entire system, avoiding increased film brittleness due to excessive crosslinking, and also improving the water resistance of the coating. Therefore, the combination of KH-560 and methyltrimethoxysilane makes the modification process controllable and also improves the flexibility and water resistance of the paint film.

[0018] In a preferred embodiment, the micro-nano filler is composed of titanium dioxide, carbon black, barium sulfate and hydrotalcite-based two-dimensional nanosheets in a weight ratio of (10-12):(2-3):(6-9):(3-6).

[0019] In a preferred embodiment, the titanium dioxide is composed of titanium dioxide with a particle size of 1-3 μm and titanium dioxide with a particle size of 5-10 μm in a weight ratio of 3:5; the carbon black has a particle size of 0.1-0.5 μm; the barium sulfate has a particle size of 0.5-1 μm; and the hydrotalcite-based two-dimensional nanosheets have a particle size of 50 nm.

[0020] By adopting the above technical solution, when the above filler particle sizes are used in combination, the larger particles, such as titanium dioxide with a particle size of 1-3μm and 5-10μm, can form a skeleton support, while the smaller particles can fill the gaps between the larger particles, making the fillers tightly packed together and forming a dense network structure. This enhances the coating's impermeability and reduces cracking and peeling caused by shrinkage stress. In addition, the hydrotalcite-based two-dimensional nanosheets can capture and fix corrosive anions that penetrate into the coating, preventing them from reaching the surface of the metal substrate and causing pitting corrosion, thus improving the coating's corrosion resistance and weather resistance and extending its service life.

[0021] In a preferred embodiment, the hydrotalcite-based two-dimensional nanosheets are obtained by the following preparation method:

[0022] S1. Add magnesium aluminum nitrate hydrotalcite to formamide at a solid-liquid ratio of 1-5 g / L, mix, and then sonicate for 4-5 hours to obtain a stripping solution.

[0023] S2. Dissolve sodium chloride in water, wherein the amount of sodium chloride used is 20-30% of the weight of magnesium aluminum nitrate hydrotalcite;

[0024] S3. Under stirring and nitrogen protection, the stripping solution and sodium chloride solution are added to the container simultaneously. After stirring for 30 minutes, the mixture is centrifuged and washed to obtain hydrotalcite-based two-dimensional nanosheets.

[0025] In a preferred embodiment, the thickener is a nonionic polyurethane associative thickener.

[0026] In a preferred embodiment, the other additives include 1.2-1.5 parts by weight of a drying agent, 0.3-0.7 parts by weight of a silver busbar additive, and 0.2-0.4 parts by weight of a flash rust inhibitor.

[0027] A second aspect of the present invention is to provide a method for preparing the above-mentioned water-based single-component inorganic anti-corrosion coating, comprising the following steps:

[0028] S1. After stirring and dispersing the silane-modified potassium silicate emulsion and the water-based acrylic emulsion, add triethylamine and stir evenly, then add other additives and water and stir evenly.

[0029] S2. Isopropanol, dipropylene glycol butyl ether, and micro / nano-scale fillers are added under stirring and stirred until evenly dispersed. Thickener is then added and stirred until evenly mixed to obtain an inorganic anti-corrosion coating.

[0030] By adopting the above technical solution, when the silane-modified potassium silicate emulsion and the aqueous acrylic emulsion are dispersed first, the compatibility between the silane-modified potassium silicate and the acrylic emulsion can be improved. This also avoids the preferential reaction between potassium silicate and micro / nano-scale fillers, which would hinder the subsequent bonding with acrylic acid, and also avoids the agglomeration of fillers in the system.

[0031] In summary, the present invention has the following beneficial effects:

[0032] 1. This water-based single-component inorganic anti-corrosion coating uses silane-modified potassium silicate emulsion, water-based acrylic emulsion, etc. as raw materials, which can give full play to the advantages of inorganic silicate coatings such as low pollution, heat resistance, corrosion resistance, non-fading and low cost.

[0033] 2. This coating can reduce cracking or peeling caused by insufficient coating flexibility, prevent moisture, oxygen and corrosive media from penetrating through cracks, and improve weather resistance and corrosion resistance.

[0034] 3. This coating combines the properties of different raw materials and is expected to provide good protection in the field of metal surface corrosion prevention, thereby improving the service life and safety of metal products. Detailed Implementation

[0035] The present invention will be further described in detail below with reference to embodiments. All details not specifically stated herein are based on conventional conditions or conditions recommended by the manufacturer. All reagents and instruments, unless otherwise stated below, are commercially available conventional reagent products.

[0036] Preparation Example 1.1

[0037] The preparation method of silane-modified potassium silicate emulsion includes the following steps:

[0038] S1. Add nano-silica sol (solid content 30%, particle size 20nm) to potassium silicate solution (modulus 3.5, solid content 35%), control the pH at 9, and stir the reaction at 40℃ for 35min to obtain a mixture. The amount of potassium silicate solution used is 1kg, and the amount of nano-silica sol used is 40% of the solid content of potassium silicate solution, that is, 0.14kg of nano-silica sol.

[0039] S2. The silane coupling agent is added to a mixed solvent of ethanol and water (volume ratio of ethanol to water is 9:1) and hydrolyzed to form a silane hydrolysate; the amount of silane coupling agent used is 20% of the solid content of the potassium silicate solution, that is, the total amount of silane coupling agent used is 0.07 kg. The silane coupling agent is composed of KH-560 and methyltrimethoxysilane in a weight ratio of 3:7.

[0040] S3. Add the silane hydrolysate to the mixture from step S1 and react at 50°C for 2 hours to obtain a silane-modified potassium silicate emulsion.

[0041] Preparation Example 1.2

[0042] The preparation method of silane-modified potassium silicate emulsion includes the following steps:

[0043] S1. Add nano-silica sol (solid content 30%, particle size 20nm) to potassium silicate solution (modulus 3.5, solid content 35%), control the pH at 10, and stir the reaction at 50℃ for 30min to obtain a mixture. The amount of potassium silicate solution used is 1kg, and the amount of nano-silica sol used is 50% of the solid content of potassium silicate solution, that is, 0.175kg of nano-silica sol.

[0044] S2. The silane coupling agent is added to a mixed solvent of ethanol and water (volume ratio of ethanol to water is 9:1) and hydrolyzed to form a silane hydrolysate; the amount of silane coupling agent used is 25% of the solid content of the potassium silicate solution, that is, the total amount of silane coupling agent used is 0.0875 kg. The silane coupling agent is composed of KH-560 and methyltrimethoxysilane in a weight ratio of 4:6.

[0045] S3. Add the silane hydrolysate to the mixture from step S1 and react at 60°C for 1 hour to obtain a silane-modified potassium silicate emulsion.

[0046] Comparative preparation example 1.1

[0047] The preparation method of the silane-modified potassium silicate emulsion differs from that of Preparation Example 1.1 in that the silane coupling agent is composed of KH-550 and vinyltriethoxysilane in a weight ratio of 3:7, while all other aspects are the same as in Preparation Example 1.1.

[0048] Comparative preparation example 1.2

[0049] The preparation method of the silane-modified potassium silicate emulsion differs from that of Preparation Example 1.1 in that the silane coupling agent is composed of KH-560 and vinyltriethoxysilane in a weight ratio of 3:7, while all other aspects are the same as in Preparation Example 1.1.

[0050] Preparation Example 2.1

[0051] The preparation method of hydrotalcite-based two-dimensional nanosheets includes the following steps:

[0052] S1. Preparation of magnesium aluminum nitrate hydrotalcite: Weigh 769g of Mg(NO3)2·6H2O and 375g of Al(NO3)3·9H2O and add them to 4L of water and stir until homogeneous to obtain a salt solution; add 320g of sodium hydroxide and 212g of sodium carbonate to 4L of water and stir until homogeneous to obtain an alkaline solution. Under nitrogen protection, mix the salt solution and the alkaline solution, adjust the pH to about 11 with sodium hydroxide and stir for 10min until the reaction is complete. Pour the solution into a high-pressure reactor and crystallize at 125℃ for 15h. After crystallization, remove the solution, cool it at room temperature, wash the hydrotalcite with water until the pH reaches 7, dry it, and grind it to a particle size of 50nm to obtain magnesium aluminum nitrate hydrotalcite.

[0053] S2. Add magnesium aluminum nitrate hydrotalcite to formamide at a solid-liquid ratio of 1 g / L, mix and then sonicate for 4 hours to obtain the stripping solution.

[0054] S3. Dissolve sodium chloride in water, the amount of sodium chloride being 20% ​​of the weight of magnesium aluminum nitrate hydrotalcite;

[0055] S4. Under stirring and nitrogen protection, the stripping solution and sodium chloride solution are added to the container simultaneously. After stirring for 30 minutes, the mixture is centrifuged and washed to obtain hydrotalcite-based two-dimensional nanosheets.

[0056] Preparation Example 2.2

[0057] The preparation method of hydrotalcite-based two-dimensional nanosheets includes the following steps:

[0058] S1. Preparation of magnesium aluminum nitrate hydrotalcite: Weigh 769g of Mg(NO3)2·6H2O and 375g of Al(NO3)3·9H2O and add them to 4L of water and stir until homogeneous to obtain a salt solution; add 320g of sodium hydroxide and 212g of sodium carbonate to 4L of water and stir until homogeneous to obtain an alkaline solution. Under nitrogen protection, mix the salt solution and the alkaline solution, adjust the pH to about 11 with sodium hydroxide and stir for 10min until the reaction is complete. Pour the solution into a high-pressure reactor and crystallize at 125℃ for 15h. After crystallization, remove the solution, cool it at room temperature, wash the hydrotalcite with water until the pH reaches 7, dry it, and grind it to a particle size of 50nm to obtain magnesium aluminum nitrate hydrotalcite.

[0059] S2. Add magnesium aluminum nitrate hydrotalcite to formamide at a solid-liquid ratio of 5 g / L, mix and then sonicate for 5 h to obtain a stripping solution.

[0060] S3. Dissolve sodium chloride in water, the amount of sodium chloride being 30% of the weight of magnesium aluminum nitrate hydrotalcite;

[0061] S4. Under stirring and nitrogen protection, the stripping solution and sodium chloride solution are added to the container simultaneously. After stirring for 30 minutes, the mixture is centrifuged and washed to obtain hydrotalcite-based two-dimensional nanosheets.

[0062] Example 1

[0063] A water-based, single-component inorganic anti-corrosion coating comprises the following raw materials: 0.6 kg of silane-modified potassium silicate emulsion obtained in Preparation Example 1.1, 1.8 kg of water-based acrylic emulsion, 2.5 kg of micro / nano-scale filler, 0.16 kg of nonionic polyurethane associative thickener, 0.25 kg of isopropanol, 0.2 kg of dipropylene glycol butyl ether, 0.08 kg of triethylamine, 0.17 kg of other additives, and 2.4 kg of water;

[0064] The micro-nano filler is composed of titanium dioxide, carbon black, barium sulfate, and hydrotalcite-based two-dimensional nanosheets obtained in Preparation Example 2.1 in a weight ratio of 10:2:6:3.

[0065] Titanium dioxide is composed of titanium dioxide with a particle size of 1-3μm and titanium dioxide with a particle size of 5-10μm in a weight ratio of 3:5; carbon black has a particle size of 0.1-0.5μm; barium sulfate has a particle size of 0.5-1μm; and hydrotalcite-based two-dimensional nanosheets have a particle size of 50nm.

[0066] Other additives include 0.12 kg of drier (water-based cobalt drier with 8% cobalt content), 0.03 kg of silver busbar additive (brand: Lencolo, model: Lencolo8921W), and 0.02 kg of flash rust inhibitor;

[0067] Its preparation method includes the following steps:

[0068] S1. After stirring and dispersing the silane-modified potassium silicate emulsion and the aqueous acrylic emulsion, add triethylamine and stir for 5 minutes, then add the drying agent and stir for 10 minutes, then add the silver busbar additive and water and stir for 10 minutes.

[0069] S2. Add isopropanol, dipropylene glycol butyl ether, titanium dioxide and carbon black under stirring and stir for 10 minutes. Then add barium sulfate, hydrotalcite-based two-dimensional nanosheets and anti-flash rust agent and stir for 5 minutes. Add thickener and stir at high speed until uniform to obtain inorganic anti-corrosion coating.

[0070] Example 2

[0071] A water-based, single-component inorganic anti-corrosion coating comprises the following raw materials: 0.8 kg of silane-modified potassium silicate emulsion obtained in Preparation Example 1.1, 2.2 kg of water-based acrylic emulsion, 3.0 kg of micro / nano-scale filler, 0.2 kg of nonionic polyurethane associative thickener, 0.27 kg of isopropanol, 0.25 kg of dipropylene glycol butyl ether, 0.1 kg of triethylamine, 0.22 kg of other additives, and 2.6 kg of water;

[0072] The micro-nano filler is composed of titanium dioxide, carbon black, barium sulfate, and hydrotalcite-based two-dimensional nanosheets obtained in Preparation Example 2.1 in a weight ratio of 10:2:6:3.

[0073] Titanium dioxide is composed of titanium dioxide with a particle size of 1-3μm and titanium dioxide with a particle size of 5-10μm in a weight ratio of 3:5; carbon black has a particle size of 0.1-0.5μm; barium sulfate has a particle size of 0.5-1μm; and hydrotalcite-based two-dimensional nanosheets have a particle size of 50nm.

[0074] Other additives include 0.14 kg of drier (water-based cobalt drier with 8% cobalt content), 0.05 kg of silver busbar additive (brand: Lencolo, model: Lencolo8921W), and 0.03 kg of flash rust inhibitor;

[0075] The preparation method is the same as in Example 1.

[0076] Example 3

[0077] A water-based, single-component inorganic anti-corrosion coating comprises the following raw materials: 1 kg of silane-modified potassium silicate emulsion obtained in Preparation Example 1.1, 2.5 kg of water-based acrylic emulsion, 3.5 kg of micro / nano-scale filler, 0.25 kg of nonionic polyurethane associative thickener, 0.3 kg of isopropanol, 0.3 kg of dipropylene glycol butyl ether, 0.12 kg of triethylamine, 0.26 kg of other additives, and 2.9 kg of water;

[0078] The micro-nano filler is composed of titanium dioxide, carbon black, barium sulfate, and hydrotalcite-based two-dimensional nanosheets obtained in Preparation Example 2.1 in a weight ratio of 10:2:6:3.

[0079] Titanium dioxide is composed of titanium dioxide with a particle size of 1-3μm and titanium dioxide with a particle size of 5-10μm in a weight ratio of 3:5; carbon black has a particle size of 0.1-0.5μm; barium sulfate has a particle size of 0.5-1μm; and hydrotalcite-based two-dimensional nanosheets have a particle size of 50nm.

[0080] Other additives include 0.15 kg of drier (water-based cobalt drier with 8% cobalt content), 0.07 kg of silver busbar additive (brand: Lencolo, model: Lencolo8921W), and 0.04 kg of flash rust inhibitor;

[0081] The preparation method is the same as in Example 1.

[0082] Example 4

[0083] A water-based single-component inorganic anti-corrosion coating differs from Example 2 in that the micro-nano filler is composed of titanium dioxide, carbon black, barium sulfate, and hydrotalcite-based two-dimensional nanosheets obtained in Preparation Example 2.1 in a weight ratio of 12:3:9:6, while all other aspects are the same as in Example 2.

[0084] Example 5

[0085] A water-based single-component inorganic anti-corrosion coating differs from Example 2 in that the silane-modified potassium silicate emulsion is obtained using Preparation Example 1.2, and the hydrotalcite-based two-dimensional nanosheets are obtained using Preparation Example 2.2; all other aspects are the same as in Example 2.

[0086] Comparative Example 1

[0087] A water-based, single-component inorganic anti-corrosion coating differs from Example 2 in that an equal amount of unmodified potassium silicate solution is used instead of silane-modified potassium silicate emulsion; otherwise, they are identical to Example 2.

[0088] Comparative Example 2

[0089] A water-based, single-component inorganic anti-corrosion coating differs from Example 2 in that it uses an unmodified potassium silicate solution (solid content 35%, modulus 3.5), and also incorporates nano-silica sol (solid content 30%, particle size 20nm) and a silane coupling agent (the silane coupling agent is composed of KH-560 and methyltrimethoxysilane in a weight ratio of 3:7). The amount of nano-silica sol is 40% of the solid content of the potassium silicate solution, and the amount of silane coupling agent is 20% of the solid content of the potassium silicate solution. All other aspects are the same as in Example 2.

[0090] Comparative Example 3

[0091] A water-based, single-component inorganic anti-corrosion coating differs from Example 2 in that the silane-modified potassium silicate emulsion used is the silane-modified potassium silicate emulsion obtained in Comparative Preparation Example 1.1, while all other aspects are the same as in Example 2.

[0092] Comparative Example 4

[0093] A water-based, single-component inorganic anti-corrosion coating differs from Example 2 in that the silane-modified potassium silicate emulsion used is the silane-modified potassium silicate emulsion obtained in Comparative Preparation Example 1.2, while all other aspects are the same as in Example 2.

[0094] Comparative Example 5

[0095] A water-based single-component inorganic anti-corrosion coating differs from Example 2 in that the micro-nano filler contains no anhydrous talc-based two-dimensional nanosheets, and is composed only of titanium dioxide, carbon black, and barium sulfate in a weight ratio of 8:2:6. All other aspects are the same as in Example 2.

[0096] Comparative Example 6

[0097] A water-based single-component inorganic anti-corrosion coating differs from Example 2 in that the particle size of titanium dioxide and carbon black is 1-10 micrometers, while all other aspects are the same as in Example 2.

[0098] Comparative Example 7

[0099] A method for preparing a water-based, single-component inorganic anti-corrosion coating differs from that in Example 2, as detailed below:

[0100] S1. Mix the silane-modified potassium silicate emulsion with triethylamine, drier, silver busbar additive, water, isopropanol, dipropylene glycol butyl ether, titanium dioxide, carbon black, barium sulfate, hydrotalcite-based two-dimensional nanosheets and anti-flash rust agent until homogeneous.

[0101] S2. Add water-based acrylic emulsion and thickener to step S1 and stir to mix evenly to obtain inorganic anti-corrosion coating. Everything else is the same as in Example 2.

[0102] Performance testing

[0103] The inorganic anti-corrosion coatings obtained in the above embodiments and comparative examples were sprayed onto tinplate. Before spraying, the tinplate was degreased and derusted. The coating thickness was 80 μm. The properties of the dried coating were tested, and the test results are shown in Table 1.

[0104] Adhesion was tested using the cross-cut test method.

[0105] The impact resistance test involves dropping a 1kg steel ball onto the plate in ascending order until the coating cracks, and recording the drop height.

[0106] The water resistance test is conducted by immersing two-thirds of the board in water for 48 hours under constant temperature conditions, then removing it, wiping it dry, and observing for any bubbles, peeling, or other phenomena.

[0107] Salt spray resistance test: The board is placed in a 3.5% sodium chloride solution and tested at a pressure of 0.1 MPa and a temperature of 35°C until the surface of the board shows signs of rusting, discoloration or blistering.

[0108] Weather resistance was tested under ultraviolet light according to GB / T14522-2008. The light source wavelength was 313nm, the light irradiance was 0.71±0.02W / m2, the light temperature was 60±3℃, the light cycle was 4h, the condensation temperature was 50±3℃, and the condensation cycle was 4h. After 3000h of cyclic testing with a light cycle of 4h light and 4h condensation, the crack resistance and chalking degree of the paint and varnish coatings were evaluated according to GB / T1766-2008.

[0109] The evaluation criteria for crack resistance are as follows:

[0110] grade Number of cracks grade Crack size 0 No visible cracks 0 No visible cracks were observed under a 10x magnifying glass. 1 Very few cracks, so few they are almost negligible. 1 The cracks are only visible under a 10x magnifying glass. 2 A small number of noticeable cracks 2 The crack is barely visible to the naked eye under normal vision. 3 Moderate number of cracks 3 The crack is clearly visible to the naked eye under normal vision. 4 A large number of cracks 4 The cracks are approximately 1mm wide. 5 Dense cracking 5 Cracks wider than 1mm

[0111] The crack depth is expressed as follows:

[0112] a) Indicates surface cracking that does not penetrate the paint film;

[0113] b. This indicates a crack that penetrates the surface paint film but has virtually no effect on the underlying paint layers.

[0114] c. Indicates a crack that penetrates the entire paint film system, revealing the substrate.

[0115] Table 1. Results of Coating Performance Tests

[0116]

[0117] Note: Cracking grade 1 (S1) b indicates that the number of cracks is grade 1, the size of the crack is grade S1, and b means that the crack penetrates the surface paint film but does not affect the underlying layer.

[0118] Based on the test results in Table 1:

[0119] The anti-corrosion coatings obtained in Examples 1-5 of this application have excellent adhesion, impact resistance, salt spray resistance, water resistance and weather resistance, which shows that the interaction between the raw materials in this application effectively improves the various properties of the coating.

[0120] Compared with Example 2, when the potassium silicate solution was not modified in advance, the compatibility between potassium silicate and acrylic emulsion was poor, resulting in weak adhesion between the cured coating and the substrate, high internal stress, and reduced performance of the coating.

[0121] Compared with Example 2, when potassium silicate solution was modified with KH-550 and vinyltriethoxysilane, all its properties decreased. When an equal amount of vinyltriethoxysilane was used instead of methyltrimethoxysilane, the water resistance and salt spray resistance of the coating in Comparative Example 4 decreased. This further illustrates that the modification of potassium silicate with the two silane coupling agents in this application effectively improves the various properties of the coating.

[0122] Compared with Example 2, Comparative Example 5 showed that the coating properties were reduced when the hydrotalcite-based two-dimensional nanosheets were missing. This is because the layered structure of the hydrotalcite-based two-dimensional nanosheets not only strengthens the coating but also improves its barrier effect. Therefore, their absence leads to a significant reduction in the coating properties.

[0123] Compared with Example 2, when the particle size of titanium dioxide and carbon black increased, the large particle size coating caused the surface roughness of the coating to increase. At the same time, it also prevented the filler particles from being tightly packed together, forming larger voids, which led to a decrease in various properties.

[0124] Compared with Example 2, in Comparative Example 7, when silane-modified potassium silicate is mixed with fillers and other raw materials, potassium silicate preferentially adsorbs onto the surface of the filler, occupies reaction sites, hinders subsequent bonding with acrylic acid, and easily leads to the formation of large agglomerates in the filler in the system, which significantly reduces the flexibility, water resistance, weather resistance and other properties of the coating.

[0125] The embodiments described herein are merely illustrative of preferred embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Therefore, all equivalent changes made in accordance with the structure, shape, and principle of the present invention should be covered within the scope of protection of the present invention.

Claims

1. A water-based, single-component inorganic anti-corrosion coating, characterized in that, The raw materials include the following parts by weight: 6-10 parts of silane-modified potassium silicate emulsion, 18-25 parts of water-based acrylic emulsion, 25-35 parts of micro / nano-grade filler, 1.6-2.5 parts of thickener, 2.5-3 parts of isopropanol, 2-3 parts of dipropylene glycol butyl ether, 0.8-1.2 parts of triethylamine, 1.7-2.6 parts of other additives, and 24-29 parts of water.

2. The water-based single-component inorganic anti-corrosion coating according to claim 1, characterized in that: The silane-modified potassium silicate emulsion was obtained by the following preparation method: S1. Add nano-silica sol to potassium silicate solution, control the pH at 9-10, and stir the reaction at 40-50℃ for 30-35 minutes to obtain a mixture; S2. Add the silane coupling agent to a mixed solvent of ethanol and water and hydrolyze it to form a silane hydrolysate; S3. Add the silane hydrolysate to the mixture from step S1 and react at 50-60℃ for 1-2 hours to obtain a silane-modified potassium silicate emulsion.

3. The water-based single-component inorganic anti-corrosion coating according to claim 2, characterized in that: The amount of the nano-silica sol used is 40-50% of the solid content of the potassium silicate solution, and the amount of the silane coupling agent used is 20-25% of the solid content of the potassium silicate solution.

4. The water-based single-component inorganic anti-corrosion coating according to claim 3, characterized in that: The silane coupling agent is composed of KH-560 and methyltrimethoxysilane in a weight ratio of (3-4):(6-7).

5. The water-based single-component inorganic anti-corrosion coating according to claim 1, characterized in that: The micro-nano filler is composed of titanium dioxide, carbon black, barium sulfate and hydrotalcite-based two-dimensional nanosheets in a weight ratio of (10-12):(2-3):(6-9):(3-6).

6. The water-based single-component inorganic anti-corrosion coating according to claim 5, characterized in that: The titanium dioxide is composed of titanium dioxide with a particle size of 1-3 μm and titanium dioxide with a particle size of 5-10 μm in a weight ratio of 3:5; the carbon black has a particle size of 0.1-0.5 μm; the barium sulfate has a particle size of 0.5-1 μm; and the hydrotalcite-based two-dimensional nanosheets have a particle size of 50 nm.

7. The water-based single-component inorganic anti-corrosion coating according to claim 5, characterized in that: The hydrotalcite-based two-dimensional nanosheets were obtained using the following preparation method: S1. Add magnesium aluminum nitrate hydrotalcite to formamide at a solid-liquid ratio of 1-5 g / L, mix, and then sonicate for 4-5 hours to obtain a stripping solution. S2. Dissolve sodium chloride in water, wherein the amount of sodium chloride used is 20-30% of the weight of magnesium aluminum nitrate hydrotalcite; S3. Under stirring and nitrogen protection, the stripping solution and sodium chloride solution are added to the container simultaneously. After stirring for 30 minutes, the mixture is centrifuged and washed to obtain hydrotalcite-based two-dimensional nanosheets.

8. The water-based single-component inorganic anti-corrosion coating according to claim 1, characterized in that: The thickener is a nonionic polyurethane associative thickener.

9. The water-based single-component inorganic anti-corrosion coating according to claim 1, characterized in that: The other additives include 1.2-1.5 parts by weight of drier, 0.3-0.7 parts by weight of silver busbar additive, and 0.2-0.4 parts by weight of flash rust inhibitor.

10. A method for preparing a water-based single-component inorganic anti-corrosion coating according to any one of claims 1-9, characterized in that: Includes the following steps: S1. After stirring and dispersing the silane-modified potassium silicate emulsion and the water-based acrylic emulsion, add triethylamine and stir evenly, then add other additives and water and stir evenly. S2. Isopropanol, dipropylene glycol butyl ether, and micro / nano-scale fillers are added under stirring and stirred until evenly dispersed. Thickener is then added and stirred until evenly mixed to obtain an inorganic anti-corrosion coating.

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