A durable polysiloxane silicone rubber anticorrosive coating and its preparation method

Abstract

This invention discloses a durable polysiloxane silicone rubber anticorrosive coating and its preparation method, belonging to the field of coating preparation technology. The durable polysiloxane silicone rubber anticorrosive coating of this invention comprises at least: 25-35 parts of hydroxyl-terminated polydimethylsiloxane; 10-18 parts of methylphenyl silicone resin prepolymer; 1-2 parts of γ-aminopropyltriethoxysilane; 1-2 parts of 3-mercaptopropyltrimethoxysilane; 3-6 parts of tetraethoxysilane; 5-10 parts of modified nano-silica sol; 10-20 parts of modified mica iron oxide; 5-10 parts of environmentally friendly corrosion inhibitor; 2-8 parts of rutile titanium dioxide; 1-3 parts of hydrophobic fumed silica; 8-12 parts of environmentally friendly diluent; 0.3-0.8 parts of organobismuth catalyst; and 0.2-0.5 parts of organosilicon leveling agent. The durable polysiloxane silicone rubber anticorrosive coating prepared by this invention possesses weather resistance, salt spray resistance, and self-healing properties.

Description

Technical Field

[0001] This invention relates to the field of coating preparation technology, specifically to a durable polysiloxane silicone rubber anticorrosive coating and its preparation method. Background Technology

[0002] Atmospheric corrosion is the most common form of metal corrosion in the natural environment. Increased humidity, higher levels of pollutants, and higher temperatures exacerbate corrosion. Conventional anti-corrosion coatings experience a sharp decline in their corrosion resistance under high temperature, high humidity, and weak acid / alkali conditions. Coating technology is one of the most effective methods to slow down material corrosion. Coatings not only provide a decorative effect to the substrate but also protect it from damage. Generally, coatings consist mainly of film-forming agents, pigments, fillers, solvents, and additives.

[0003] As a film-forming material in coatings, silicone resins hold a significant position in the coatings industry due to their unique thermal and oxidative stability. Silicone coatings use silicone polymers or silicone-modified polymers as the main film-forming substance. They possess excellent heat and cold resistance, electrical insulation, corona resistance, radiation resistance, moisture and water repellency, weather resistance, stain resistance, and chemical corrosion resistance. In recent years, they have seen rapid development in product performance improvement and application. Coatings made with silicone resins as the film-forming substance mainly include heat-resistant and weather-resistant silicone anti-corrosion coatings, scratch-resistant transparent silicone coatings, release and moisture-proof coatings, and radiation-resistant coatings. Despite the many excellent properties of silicone resins, some problems exist: poor adhesion to substrates, poor resistance to organic solvents, poor mechanical strength of the film at high temperatures, high price, poor impact resistance, and easy rubbing, resulting in shorter anti-corrosion time and poor durability. Therefore, finding an anti-corrosion coating with good adhesion and excellent anti-corrosion performance is an urgent problem to be solved. Summary of the Invention

[0004] The purpose of this invention is to provide a durable polysiloxane silicone rubber anticorrosive coating and its preparation method, thereby solving the following technical problems:

[0005] Existing polysiloxane silicone rubber anticorrosive coatings suffer from poor adhesion, poor impact resistance, and lack of durability.

[0006] The objective of this invention can be achieved through the following technical solutions:

[0007] A durable polysiloxane silicone rubber anticorrosive coating comprises at least the following raw materials in parts by weight:

[0008] Hydroxyl-terminated polydimethylsiloxane 25-35 parts; methylphenyl silicone resin prepolymer 10-18 parts; γ-aminopropyltriethoxysilane 1-2 parts; 3-mercaptopropyltrimethoxysilane 1-2 parts; tetraethoxysilane 3-6 parts; modified nano-silica sol 5-10 parts; modified mica iron oxide 10-20 parts; environmentally friendly corrosion inhibitor 5-10 parts; rutile titanium dioxide 2-8 parts; hydrophobic fumed silica 1-3 parts; environmentally friendly diluent 8-12 parts; organobismuth catalyst 0.3-0.8 parts; organosilicon leveling agent 0.2-0.5 parts.

[0009] As a further aspect of the present invention: the methylphenyl silicone resin prepolymer is prepared by mixing methyltrichlorosilane, dimethyldichlorosilane, diphenyldichlorosilane and phenyltrichlorosilane, dissolving them in xylene, and then adding an aqueous solution of acetone, and the phenyl content in the methylphenyl silicone resin prepolymer is 20-30%.

[0010] As a further aspect of the present invention: the method for preparing the modified nano-silica sol:

[0011] Anhydrous ethanol, deionized water and ammonia were mixed, and then tetraethyl orthosilicate was added to obtain nano silica sol.

[0012] Divinyltetramethyldisilazane was added to the nano-silica sol to obtain modified nano-silica sol.

[0013] As a further aspect of the present invention: the ammonia water is a 25-30 wt% ammonia solution, and the molar ratio of the anhydrous ethanol, the deionized water, the ammonia water and the tetraethyl orthosilicate is 8-12:4-6:1:0.8-1.2.

[0014] As a further aspect of the present invention: the molar ratio of the divinyltetramethyldisilazane to the nano-silica sol is 0.5-0.8:1.

[0015] As a further aspect of the present invention, the preparation method of the modified mica iron oxide includes the following steps:

[0016] Modified ferric oxide of mica was obtained by dispersing it in deionized water, adding hydrolyzed silane coupling agent, reacting, washing and drying.

[0017] As a further aspect of the present invention: the silane coupling agent is N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, and the mass ratio of the silane coupling agent to the mica iron oxide is 1-3:100.

[0018] As a further aspect of the present invention: the environmentally friendly corrosion inhibitor is one or more of benzotriazole, sodium molybdate, and phytic acid, or a mixture thereof; and the environmentally friendly diluent is one or more of propylene glycol methyl ether acetate and sodium dodecylbenzene sulfonate.

[0019] A method for preparing a durable polysiloxane silicone rubber anticorrosive coating includes at least the following preparation steps:

[0020] Hydroxyl-terminated polydimethylsiloxane, methylphenylsilicon resin prepolymer, γ-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, tetraethoxysilane, modified nano-silica sol, and hydrophobic fumed silica are added to a kneading cylinder and kneaded under high temperature and vacuum to obtain the base material.

[0021] The base material is ground using a three-roll mill until the fineness is ≤30μm;

[0022] Modified mica iron oxide, environmentally friendly corrosion inhibitor, rutile titanium dioxide, environmentally friendly diluent, organic bismuth catalyst and organic silicone leveling agent are then added to the base material, mixed and stirred evenly, and then vacuum stirred to obtain a durable polysiloxane silicone rubber anti-corrosion coating.

[0023] The beneficial effects of this invention are:

[0024] This invention uses hydroxyl-terminated polydimethylsiloxane and methylphenyl silicone resin prepolymer as the base material system, γ-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane and tetraethoxysilane as coupling agents and crosslinking agents, and modified nano-silica sol, modified mica iron oxide and rutile titanium dioxide as anti-corrosion and reinforcing fillers. With the addition of other functional additives, a durable polysiloxane silicone rubber anti-corrosion coating is obtained. The anti-corrosion coating prepared by this invention is a pure organosilicon system. Combined with high crosslinking and densification, the prepared coating has strong adhesion, high-efficiency shielding and active protection properties. It is suitable for substrates with low surface treatment and has good compatibility with various coatings, applicable to both new and old substrates. The cured anti-corrosion coating prepared by this invention combines the functions of traditional coatings with the substrate surface, exhibiting excellent aging resistance, corrosion resistance, and salt spray resistance. The coating is elastic, adapting to the expansion and contraction of the substrate to prevent cracking. Damaged areas can be directly repaired without interface reaction, and the repaired coating integrates seamlessly with the original coating.

[0025] In this invention, the hydroxyl-terminated polydimethylsiloxane in the base material of the anti-corrosion coating provides an elastic silicone rubber skeleton, giving the coating flexibility and weather resistance. The flexible Si-O-Si main chain gives the coating high elongation, resisting the thermal expansion and contraction stress of the substrate, and its high bond energy enables it to resist ultraviolet radiation, oxidation, and chemical corrosion. Methylphenyl silicone resin prepolymer increases the coating's hardness and heat resistance, while the phenyl groups enhance weather resistance. When combined with hydroxyl-terminated polydimethylsiloxane, it forms a "rigid-flexible" network structure, balancing the coating's toughness and strength, resulting in excellent mechanical and impact resistance. This invention also incorporates a γ-aminopropyltriethoxysilane and 3-mercaptopropyltrimethoxysilane bissilane system. Through functional complementarity and synergistic effects, this significantly improves the overall performance of the coating. The -NH2 groups of the aminosilane form coordination bonds and amide bonds with the metal substrate / existing coating, while the -SH groups of the mercaptosilane penetrate the oil or water film interface, improving coating adhesion and interfacial bonding, preventing filler agglomeration, and enhancing the overall integrity of the coating. The tetraethoxysilane added in this invention acts as a crosslinking agent. Upon hydrolysis, it generates silanol, which condenses with the hydroxyl groups of the base material to form a Si-O-Si crosslinking network, improving the coating's hardness, solvent resistance, and chemical stability. The crosslinking system in this invention contains unreacted Si-OH and -SH groups, which condense with the new coating during repair, achieving chemical bonding. It continues to cure at room temperature, and the interface between the old and new coatings fuses together through siloxane rearrangement, without interfacial reaction.

[0026] This invention also incorporates modified mica iron oxide and nano-silica sol as fillers. The modified mica iron oxide is modified with N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane. The lamellar structure of the mica iron oxide forms a "scale-layered" barrier effect, extending the penetration path of corrosive media. N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane has long organic chains, resulting in greater steric hindrance and forming an organic coating layer on the surface of the mica iron oxide particles. This improves the dispersibility of the modified mica iron oxide in organic media, enhances its compatibility with the base material, and improves its anti-corrosion efficiency. The modified nano-silica sol is modified with divinyltetramethyldisilazane. Divinyltetramethyldisilazane has a dual anchoring effect; the nano-sized particles fill the pores of the coating, increasing density and simultaneously enhancing the coating's hardness and wear resistance. In this invention, the combination of modified nano-silica sol and modified mica iron oxide achieves dual barrier against corrosive media through the synergy of hydrophobic chains and amine groups. At the same time, vinyl groups and mercapto groups endow the coating with self-healing ability, thereby extending the durability of the prepared coating. Detailed Implementation

[0027] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0028] Example 1: The preparation method of modified nano-silica sol includes the following steps:

[0029] Mix 500 mL of anhydrous ethanol, 100 mL of deionized water and 65 mL of 25 wt% ammonia in a three-necked flask, then slowly add 200 mL of tetraethyl orthosilicate. Stir the mixture in a water bath for 4 hours and let it stand for 1 hour to obtain nano-silica sol.

[0030] 120 mL of divinyltetramethyldisilazane was slowly added dropwise to the above nano-silica sol, and the mixture was stirred in a water bath for 2 h. After standing for 30 min, the modified nano-silica sol was obtained.

[0031] Example 2: The preparation method of modified nano-silica sol includes the following steps:

[0032] Mix 500 mL of anhydrous ethanol, 100 mL of deionized water and 65 mL of 25 wt% ammonia in a three-necked flask, then slowly add 200 mL of tetraethyl orthosilicate. Stir the mixture in a water bath for 4 hours and let it stand for 1 hour to obtain nano-silica sol.

[0033] 130 mL of divinyltetramethyldisilazane was slowly added dropwise to the above nano-silica sol, and the mixture was stirred in a water bath for 2 h. After standing for 30 min, the modified nano-silica sol was obtained.

[0034] Example 3: The preparation method of modified mica iron oxide includes the following steps:

[0035] 100g of mica iron oxide was added to a three-necked flask, and 40ml of deionized water was added. The mixture was dispersed in a 60℃ water bath by high-speed stirring for 30min at a speed of 1100-1300r / min. Anhydrous ethanol and deionized water were prepared into a solution at a volume ratio of 2:1. The pH was adjusted to 8 with ammonia water. 2g of N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane was added to prepare a 5wt% solution. After hydrolysis at room temperature for 15min, the solution was added to the mica iron oxide dispersion. The mixture was stirred and reacted for 120min at a speed of 1100-1300r / min. After stirring was stopped, the mixture was washed once with deionized water and once with anhydrous ethanol. The mixture was then dried at 80℃ to obtain modified mica iron oxide.

[0036] Example 4 A durable polysiloxane silicone rubber anticorrosive coating and its preparation method, which is made by the following method:

[0037] Methyltrichlorosilane, dimethyldichlorosilane, diphenyldichlorosilane, and phenyltrichlorosilane were mixed in a molar ratio of 3:2:0.5:0.2, dissolved in xylene, and then an aqueous solution of acetone was added. The mixture was then hydrolyzed and polycondensed to obtain a methylphenyl silicone resin prepolymer with a phenyl content of 28 wt%.

[0038] 30 parts by weight of hydroxyl-terminated polydimethylsiloxane, 15 parts by weight of the above-mentioned 70% solid content methylphenyl silicone resin prepolymer, 2 parts by weight of γ-aminopropyltriethoxysilane, 1 part by weight of 3-mercaptopropyltrimethoxysilane, 5 parts by weight of tetraethoxysilane, 8 parts by weight of the modified nano silica sol with a solid content of 30% prepared in Example 1, and 1 part by weight of hydrophobic fumed silica were added into a kneading cylinder and kneaded under high temperature and vacuum to obtain the base material;

[0039] The above-mentioned base material was ground with a three-roll mill until the fineness was ≤30μm;

[0040] Then, 15 parts by weight of the modified mica iron oxide prepared in Example 3, 8 parts by weight of the environmentally friendly corrosion inhibitor benzotriazole and sodium molybdate, 4 parts by weight of rutile titanium dioxide, 10 parts by weight of the environmentally friendly diluent propylene glycol methyl ether acetate, 0.6 parts by weight of the organic bismuth catalyst and 0.4 parts by weight of the organic silicone leveling agent were added to the ground base material, mixed and stirred evenly, and then vacuum stirred to obtain a durable polysiloxane silicone rubber anticorrosion coating.

[0041] Example 5 A durable polysiloxane silicone rubber anticorrosive coating and its preparation method, which is made by the following method:

[0042] Methyltrichlorosilane, dimethyldichlorosilane, diphenyldichlorosilane, and phenyltrichlorosilane were mixed in a molar ratio of 3:2:0.5:0.2, dissolved in xylene, and then an aqueous solution of acetone was added. The mixture was then hydrolyzed and polycondensed to obtain a methylphenyl silicone resin prepolymer with a phenyl content of 28 wt%.

[0043] 30 parts by weight of hydroxyl-terminated polydimethylsiloxane, 15 parts by weight of the above-mentioned 70% solid content methylphenyl silicone resin prepolymer, 2 parts by weight of γ-aminopropyltriethoxysilane, 1 part by weight of 3-mercaptopropyltrimethoxysilane, 5 parts by weight of tetraethoxysilane, 8 parts by weight of the modified nano silica sol with a solid content of 30% prepared in Example 2, and 1 part by weight of hydrophobic fumed silica were added into a kneading cylinder and kneaded under high temperature and vacuum to obtain the base material;

[0044] The above-mentioned base material was ground with a three-roll mill until the fineness was ≤30μm;

[0045] Then, 15 parts by weight of the modified mica iron oxide prepared in Example 3, 8 parts by weight of the environmentally friendly corrosion inhibitor benzotriazole and sodium molybdate, 4 parts by weight of rutile titanium dioxide, 10 parts by weight of the environmentally friendly diluent propylene glycol methyl ether acetate, 0.6 parts by weight of the organic bismuth catalyst and 0.4 parts by weight of the organic silicone leveling agent were added to the ground base material, mixed and stirred evenly, and then vacuum stirred to obtain a durable polysiloxane silicone rubber anticorrosion coating.

[0046] Example 6 A durable polysiloxane silicone rubber anticorrosive coating and its preparation method, which is made by the following method:

[0047] Methyltrichlorosilane, dimethyldichlorosilane, diphenyldichlorosilane, and phenyltrichlorosilane were mixed in a molar ratio of 3.5:2.5:0.8:0.3, dissolved in xylene, and then an aqueous acetone solution was added. The mixture was then hydrolyzed and polycondensed to obtain a methylphenyl silicone resin prepolymer with a phenyl content of 22 wt%.

[0048] 30 parts by weight of hydroxyl-terminated polydimethylsiloxane, 15 parts by weight of the above-mentioned 70% solid content methylphenyl silicone resin prepolymer, 1.5 parts by weight of γ-aminopropyltriethoxysilane, 1.5 parts by weight of 3-mercaptopropyltrimethoxysilane, 4 parts by weight of tetraethoxysilane, 8 parts by weight of the modified nano silica sol with a solid content of 30% prepared in Example 1, and 2 parts by weight of hydrophobic fumed silica were added into a kneading cylinder and kneaded under high temperature and vacuum to obtain the base material;

[0049] The above-mentioned base material was ground with a three-roll mill until the fineness was ≤30μm;

[0050] Then, 15 parts by weight of the modified mica iron oxide prepared in Example 3, 8 parts by weight of the environmentally friendly corrosion inhibitor benzotriazole and sodium molybdate, 4 parts by weight of rutile titanium dioxide, 10 parts by weight of the environmentally friendly diluent propylene glycol methyl ether acetate, 0.6 parts by weight of the organic bismuth catalyst and 0.4 parts by weight of the organic silicone leveling agent were added to the ground base material, mixed and stirred evenly, and then vacuum stirred to obtain a durable polysiloxane silicone rubber anticorrosion coating.

[0051] Example 7 A durable polysiloxane silicone rubber anticorrosive coating and its preparation method, which is made by the following method:

[0052] Methyltrichlorosilane, dimethyldichlorosilane, diphenyldichlorosilane, and phenyltrichlorosilane were mixed in a molar ratio of 3.5:2.5:0.8:0.3, dissolved in xylene, and then an aqueous acetone solution was added. The mixture was then hydrolyzed and polycondensed to obtain a methylphenyl silicone resin prepolymer with a phenyl content of 22 wt%.

[0053] 30 parts by weight of hydroxyl-terminated polydimethylsiloxane, 15 parts by weight of the above-mentioned 70% solid content methylphenyl silicone resin prepolymer, 1.5 parts by weight of γ-aminopropyltriethoxysilane, 1.5 parts by weight of 3-mercaptopropyltrimethoxysilane, 4 parts by weight of tetraethoxysilane, 8 parts by weight of the modified nano silica sol with a solid content of 30% prepared in Example 2, and 2 parts by weight of hydrophobic fumed silica were added into a kneading cylinder and kneaded under high temperature and vacuum to obtain the base material;

[0054] The above-mentioned base material was ground with a three-roll mill until the fineness was ≤30μm;

[0055] Then, 15 parts by weight of the modified mica iron oxide prepared in Example 3, 8 parts by weight of the environmentally friendly corrosion inhibitor benzotriazole and sodium molybdate, 4 parts by weight of rutile titanium dioxide, 10 parts by weight of the environmentally friendly diluent propylene glycol methyl ether acetate, 0.6 parts by weight of the organic bismuth catalyst and 0.4 parts by weight of the organic silicone leveling agent were added to the ground base material, mixed and stirred evenly, and then vacuum stirred to obtain a durable polysiloxane silicone rubber anticorrosion coating.

[0056] Compared with Example 4, Comparative Example 1 only replaced the modified nano silica sol prepared in Example 1 with the nano silica sol prepared in Example 1 by the same mass as that in Example 4. The other components and preparation methods were completely the same as those in Example 4.

[0057] Compared with Example 4, Comparative Example 2 only replaced the modified mica iron oxide prepared in Example 3 with the unmodified mica iron oxide in Example 3. The other components and preparation methods were completely the same as those in Example 4.

[0058] Compared with Example 4, Comparative Example 3 replaced the modified nano-silica sol prepared in Example 1 with the nano-silica sol prepared in Example 1 by mass, and replaced the modified mica iron oxide prepared in Example 3 added in Example 4 with the unmodified mica iron oxide in Example 3 by mass. The remaining components and preparation methods were completely consistent with Example 4.

[0059] Compared with Example 4, Comparative Example 4 did not contain methylphenyl silicone resin prepolymer, and the hydroxyl-terminated polydimethylsiloxane was increased to 45 parts by mass, and the tetraethoxysilane was increased to 6 parts by mass. The remaining components and preparation methods were completely the same as those in Example 4.

[0060] Compared with Example 4, Comparative Example 5 replaced γ-aminopropyltriethoxysilane added in Example 4 with 3-mercaptopropyltrimethoxysilane by mass, while the remaining components and preparation methods were completely consistent with Example 4.

[0061] Compared with Example 4, Comparative Example 6 replaced 3-mercaptopropyltrimethoxysilane added in Example 4 with γ-aminopropyltriethoxysilane by mass, while the remaining components and preparation methods were completely consistent with Example 4.

[0062] Performance testing

[0063] The anti-corrosion coatings prepared in Examples 4-7 and Comparative Examples 1-6 were sprayed onto metal substrates and cured at room temperature for 7 days. After curing, the coating thickness was controlled at 150-200 μm to obtain the anti-corrosion coating, and its performance was tested.

[0064] Shore hardness test: The test was conducted according to GB / T2411-2008 standard. The testing instrument used was a Shore hardness tester model A manufactured by Mitutoyo Measuring Instruments of Japan. The sample was placed on a horizontal base, and the Shore hardness tester was held vertically. Then, it was pressed onto the sample without impact. The test position should be at least 9 mm away from the edge of the sample, and the pressure base near the probe should be in close contact with the sample during the test. The test results are shown in Table 1.

[0065] Adhesion test: The coating adhesion test was conducted according to ASTM D3359. Two approximately 40mm long cut lines were made on the coating using a scalpel, with the included angle between the two lines between 30° and 40°, and the cut lines should be exposed above the substrate. 3M adhesive tape was then applied to the cut and quickly pulled off. The condition of the cut was then observed; the test results are shown in Table 1.

[0066] Impact resistance test: The test was conducted according to the national standard "Determination of Impact Resistance of Paint Films" (GB / T1732-1993). A tinplate sheet coated with paint was placed flat on the test plate with the painted surface facing upwards. The weight was slid to the testing height and fixed. The control button was pressed, and the weight struck the test plate, creating a circular indentation. The paint film was observed for cracks, wrinkles, and peeling. The test was repeated three times; the results are shown in Table 1.

[0067] Tensile mechanical property test: The sample was cut into a rectangular shape (2×8×40mm) and then placed on the test table for tensile testing until the sample broke (clamp speed was 5.0±0.2 mm / s); the test results are shown in Table 1;

[0068] Coating self-healing test: The superhydrophobic coating sample was placed in a vacuum plasma cleaner and sputtered with air plasma at a power of 40W for 30 seconds to change the surface wettability of the sample from superhydrophobic to superhydrophilic. Then, heating was used to promote the self-healing behavior of the coating. The heating self-healing process was carried out by placing the plasma-sputtered coating in an 80℃ oven for one hour and then measuring the wettability of the coating. The test results are shown in Table 1.

[0069] Table 1: Statistical Table of Anti-corrosion Coating Performance Test Data for Examples 4-7 and Comparative Examples 2-6

[0070]

[0071] As shown in Table 1, the durable polysiloxane silicone rubber anticorrosive coating prepared in this invention exhibits excellent mechanical properties and self-healing ability. This indicates that the modified nano-silica sol and modified mica iron oxide added in this invention significantly improve the tensile strength and self-healing rate of the anticorrosive coating, and the synergistic use of the two silanes enhances the adhesion of the anticorrosive coating.

[0072] Water resistance test: Refer to GB / 1733-79 Test method for water resistance of paint film. Immerse 2 / 3 of the length of the coating test panel sealed with a mixture of paraffin and rosin into deionized water at a temperature of 23±2℃ and observe for whitening, loss of gloss, bubbles, etc.; the test results are shown in Table 2;

[0073] UV aging resistance test: The coating was placed under a UV lamp with a wavelength of 365nm for 500 hours, and the color difference ΔE was measured. ΔE<2 is good, and >5 is poor. The test results are shown in Table 2.

[0074] Solution immersion resistance test: The coating was immersed in 3.5wt% NaCl solution for 720 hours, and the presence of whitening, loss of gloss, bubbles, etc. was observed; the test results are shown in Table 2.

[0075] Salt spray corrosion resistance test: According to the test method of GB / T 1771-2007, the coating sample adopts the non-scratch test method. The sample is placed in a 35℃ salt spray chamber for salt spray performance test for 2500 hours. The coating is considered to pass if it does not blister, peel off, or show rust. The test results are shown in Table 2.

[0076] Long-term stability test: The sample was tilted horizontally at about 4.5°, and the dynamic process of water droplets rolling on the sample after 18 months of indoor storage was recorded. Maintaining hydrophobicity (contact angle >150°) was considered passing; the test results are shown in Table 2.

[0077] Table 2: Statistical Table of Anti-corrosion Coating Performance Test Data for Examples 4-7 and Comparative Examples 2-6

[0078]

[0079] As shown in Table 2, the anti-corrosion coating obtained by the durable polysiloxane silicone rubber anti-corrosion coating prepared by the present invention has good water resistance, salt spray resistance and durability.

[0080] The foregoing has provided a detailed description of one embodiment of the present invention, but this description is merely a preferred embodiment and should not be construed as limiting the scope of the invention. All equivalent variations and modifications made within the scope of the claims of this invention should still fall within the patent coverage of this invention.

Claims

1. A durable polysiloxane silicone rubber anticorrosive coating, characterized in that, It shall include at least the following parts by weight of raw materials: Hydroxyl-terminated polydimethylsiloxane 25-35 parts; methylphenyl silicone resin prepolymer 10-18 parts; γ-aminopropyltriethoxysilane 1-2 parts; 3-mercaptopropyltrimethoxysilane 1-2 parts; tetraethoxysilane 3-6 parts; modified nano-silica sol 5-10 parts; modified mica iron oxide 10-20 parts. 5-10 parts of environmentally friendly corrosion inhibitor; 2-8 parts of rutile titanium dioxide; 1-3 parts of hydrophobic fumed silica; 8-12 parts of environmentally friendly diluent; 0.3-0.8 parts of organic bismuth catalyst; 0.2-0.5 parts of organosilicon leveling agent; The methylphenyl silicone resin prepolymer is prepared by dissolving a mixture of methyltrichlorosilane, dimethyldichlorosilane, diphenyldichlorosilane, and phenyltrichlorosilane in xylene and then adding an aqueous solution of acetone. The phenyl content in the methylphenyl silicone resin prepolymer is 20-30%. The method for preparing the modified nano-silica sol: Anhydrous ethanol, deionized water and ammonia were mixed, and then tetraethyl orthosilicate was added to obtain nano silica sol. Divinyltetramethyldisilazane was added to the nano-silica sol to obtain modified nano-silica sol; The ammonia solution is a 25-30 wt% ammonia solution, and the molar ratio of the anhydrous ethanol, the deionized water, the ammonia solution, and the tetraethyl orthosilicate is 8-12:4-6:1:0.8-1.

2. The molar ratio of the divinyltetramethyldisilazane to the nano-silica sol is 0.5-0.8:

1.

2. The durable polysiloxane silicone rubber anticorrosive coating according to claim 1, characterized in that, The preparation method of the modified mica iron oxide includes the following steps: Modified ferric oxide of mica was obtained by dispersing it in deionized water, adding hydrolyzed silane coupling agent, reacting, washing and drying.

3. The durable polysiloxane silicone rubber anticorrosive coating according to claim 2, characterized in that, The silane coupling agent is N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, and the mass ratio of the silane coupling agent to the mica iron oxide is 1-3:

100.

4. The durable polysiloxane silicone rubber anticorrosive coating according to claim 1, characterized in that, The environmentally friendly corrosion inhibitor is one or a mixture of several of benzotriazole, sodium molybdate, and phytic acid, and the environmentally friendly diluent is one or a mixture of several of propylene glycol methyl ether acetate and sodium dodecylbenzene sulfonate.

5. A method for preparing a durable polysiloxane silicone rubber anticorrosive coating according to any one of claims 1-4, characterized in that, It includes at least the following preparation steps: Hydroxyl-terminated polydimethylsiloxane, methylphenylsilicon resin prepolymer, γ-aminopropyltriethoxysilane, 3-mercaptopropyltrimethoxysilane, tetraethoxysilane, modified nano-silica sol, and hydrophobic fumed silica are added to a kneading cylinder and kneaded under high temperature and vacuum to obtain the base material. The base material is ground using a three-roll mill until the fineness is ≤30μm; Modified mica iron oxide, environmentally friendly corrosion inhibitor, rutile titanium dioxide, environmentally friendly diluent, organic bismuth catalyst and organic silicone leveling agent are then added to the base material, mixed and stirred evenly, and then vacuum stirred to obtain a durable polysiloxane silicone rubber anti-corrosion coating.

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