A high-performance corrosion-resistant and environmentally friendly coating and its preparation process

Abstract

The present invention relates to the technical field of coatings, and specifically to a high-performance corrosion-resistant environmental protection coating and its preparation process. First, a flame-retardant polysiloxane and an aldehyde-functionalized phosphonate are prepared in the present invention. Then, the aldehyde-functionalized phosphonate and the flame-retardant polysiloxane react in an alkaline environment to obtain a composite silicone. Finally, epoxy resin, the composite silicone, aluminum hydroxide filler, etc. are mixed to obtain the finished coating. The finished coating prepared in the present invention has good flame retardancy, weather resistance and corrosion resistance, and thus has broad application prospects in the technical field of coatings.

Description

Technical Field

[0001] The present invention relates to the technical field of coatings, and specifically to a high-performance corrosion-resistant and environmentally friendly coating and its preparation process. Background Art

[0002] In today's rapidly developing industrial and social environment, high-performance coatings play an indispensable role in multiple fields due to their excellent physical and chemical properties. Firstly, high-performance coatings have important applications in the field of industrial anti-corrosion. As modern industrial equipment and infrastructure, such as ships, bridges, pipelines, and chemical equipment, are facing severe environmental corrosion challenges. Traditional anti-corrosion coatings often struggle to meet these requirements, but high-performance coatings, with their excellent corrosion resistance, weather resistance, and chemical resistance, effectively extend the service life of these equipment and facilities and reduce maintenance costs. Secondly, in the transportation field, due to the extremely high requirements for appearance and performance of aviation, automotive, and rail transit equipment, high-performance coatings also demonstrate their unique value. Such coatings can not only provide high-quality surface protection but also enhance the safety and comfort of the equipment. Specifically, aviation coatings need to have excellent weather resistance, heat resistance, and UV resistance to ensure the safety and reliability of aircraft during high-altitude flight; while automotive coatings need to have good abrasion resistance and chemical resistance to adapt to complex road environments. However, in specific extreme environments, such as fires, coatings may be directly exposed to dangerous factors such as high heat, flames, and smoke, which can easily trigger the combustion of combustibles or accelerate the spread of fire. Therefore, it is particularly important to develop coatings with strong flame retardant properties. Such coatings can better resist the erosion of these extreme environments, thereby reducing the fire risk and protecting the safety of building structures and personnel. Additionally, in the natural environment, coatings are long-term affected by complex climate conditions such as sunlight, rain, and temperature differences, which can easily lead to the aging, fading, and even peeling of the coatings. Therefore, coatings with strong weather resistance are also highly regarded. They can better resist the erosion of these natural factors, maintain the beauty and functionality of the coating, thereby extending its service life and reducing maintenance costs.

[0003] In order to overcome the defects of the prior art, the present invention provides a high-performance corrosion-resistant and environmentally friendly coating and its preparation process. Summary of the Invention

[0004] The purpose of the present invention is to provide a high-performance corrosion-resistant and environmentally friendly coating and its preparation process to solve the problems in the prior art.

[0005] To solve the above technical problems, the present invention provides the following technical solutions:

[0006] A preparation process for a high-performance corrosion-resistant and environmentally friendly coating, comprising the following steps:

[0007] Step 1: Dissolve hexachlorocyclotriphosphazene in xylene, slowly dropwise add ethanolamine under a nitrogen atmosphere, slowly heat up to 70 - 75 °C, stir and reflux for 12 - 15 h. After the reaction is completed, wash, dry, and remove impurities from the bottom liquid to obtain hydroxylated cyclotriphosphazene; under a nitrogen atmosphere, mix hydroxylated cyclotriphosphazene, γ-glycidoxypropyltrimethoxysilane, and stannous octoate catalyst, slowly heat up to 50 - 55 °C and stir for 8 - 10 h to obtain epoxidized cyclotriphosphazene; dissolve NH2-POSS in xylene, then add epoxidized cyclotriphosphazene and disperse evenly by ultrasonic wave, slowly heat up to 100 - 110 °C and react for 2 - 3 h to obtain flame-retardant polysiloxane;

[0008] Step 2: Under a nitrogen atmosphere, mix pentaerythritol and phosphorus trichloride sulfide, heat up to 90 - 95 °C and react for 1.0 - 1.5 h, then heat up to 140 - 150 °C and react for 7 - 9 h, then heat up to 160 - 170 °C and react for 1.0 - 1.5 h. After the reaction is completed, cool, extract, filter, spin dry, and vacuum dry to obtain hydroxylated phosphonate; dissolve hydroxylated phosphonate, p-formylbenzoic acid, and 4-dimethylaminopyridine in anhydrous dichloromethane, then add N, N-diisopropylcarbodiimide and react for 10 - 14 h. After the reaction is completed, wash with saturated sodium bicarbonate solution, saturated sodium chloride solution, deionized water, dry, and remove the solvent to obtain aldehyde-functionalized phosphonate;

[0009] Step 3: Dissolve aldehyde-functionalized phosphonate and flame-retardant polysiloxane in toluene, then add Tris buffer solution, react at 80 - 90 °C for 5 - 7 h. After the reaction is completed, cool to room temperature, take the lower-layer precipitate for centrifugation, and vacuum dry to obtain composite silicone; mix epoxy resin and xylene evenly, then add composite silicone, aluminum hydroxide filler, dispersant, and leveling agent, fully ball mill, and then add polyamide 651 curing agent to obtain the finished product.

[0010] Preferably, in Step 1, when preparing hydroxylated cyclotriphosphazene, the reaction molar ratio of hexachlorocyclotriphosphazene to ethanolamine is 1:(5 - 6).

[0011] Preferably, in Step 1, when preparing epoxidized cyclotriphosphazene, the reaction molar ratio of hydroxylated cyclotriphosphazene to γ-glycidoxypropyltrimethoxysilane is 1:(5 - 6).

[0012] Preferably, in Step 1, when preparing flame-retardant polysiloxane, the reaction molar ratio of NH2-POSS to epoxidized cyclotriphosphazene is 1:(4 - 5).

[0013] Preferably, the preparation process of NH2-POSS is as follows: Dissolve tetraethylammonium hydroxide in a mixed solvent, then slowly add 3-aminopropyltriethoxysilane dropwise, and stir and react at 60-70 °C for 20-25 h. After the reaction is completed, cool at room temperature, precipitate at low temperature, filter, and dry under vacuum to obtain NH2-POSS; the mixed solvent includes deionized water, propanol, and acetonitrile, and the volume ratio is 1:0.4:0.1; the reaction volume ratio of tetraethylammonium hydroxide and 3-aminopropyltriethoxysilane is 0.5:(55-60).

[0014] Preferably, in step two, when preparing the hydroxylated phosphonate, the reaction molar ratio of pentaerythritol and phosphorus trichloride sulfide is 1:(1.0-1.2).

[0015] Preferably, in step two, when preparing the aldehyde-group-containing phosphonate, the reaction molar ratio of the hydroxyl group in the hydroxylated phosphonate and the carboxyl group in p-carboxybenzaldehyde is 1:(3-4).

[0016] Preferably, in step three, dissolve tris(hydroxymethyl)aminomethane hydrochloride in deionized water, and then adjust the pH to 8.5-9.0 with a sodium hydroxide solution to obtain a Tris buffer solution with a concentration of 0.5-0.6 g / mL.

[0017] Preferably, in step three, when preparing the composite organosilicon, the reaction molar ratio of the aldehyde group in the aldehyde-group-containing phosphonate and the amino group in the flame-retardant polysiloxane is (1.3-1.5):1.

[0018] Preferably, in step three, the content of each component of the epoxy coating is as follows: by mass parts, 50-60 parts of epoxy resin, 25-30 parts of xylene, 13-18 parts of composite organosilicon, 8-10 parts of aluminum hydroxide filler, 1-2 parts of dispersant, 1-2 parts of leveling agent, and 25-30 parts of polyamide 651 curing agent.

[0019] The beneficial effects of the present invention are as follows:

[0020] The characteristics of the present invention are as follows. In Step 1, by adding hexachlorocyclotriphosphazene and ethanolamine, a substitution reaction occurs to obtain hydroxylated cyclotriphosphazene. Further, by adding hydroxylated cyclotriphosphazene, γ-glycidoxypropyltrimethoxysilane, and catalyst stannous octoate, a hydrolysis condensation reaction occurs, and finally epoxidized cyclotriphosphazene is prepared. Then, the epoxidized cyclotriphosphazene is added to the NH2-POSS solution, and a nucleophilic ring-opening reaction occurs to graft the epoxidized cyclotriphosphazene with multiple flame-retardant components onto the surface of cage-shaped amino-functionalized polysiloxane, obtaining flame-retardant polysiloxane. In this step, with cage-shaped amino-functionalized polysiloxane as the core, a flame-retardant structure containing silicon, nitrogen, and phosphorus is further grafted onto the surface to obtain flame-retardant polysiloxane. Among them, the introduction of a large amount of silicon elements improves the ultraviolet resistance of the material. The siloxane groups in the composite silicone can absorb and scatter ultraviolet rays, reducing the aging effect of ultraviolet rays on the material and enhancing the weather resistance of the material. In addition, the siloxane groups have excellent chemical stability and can also effectively resist the erosion of environmental factors such as moisture, enabling it to maintain stable performance in various harsh environments.

[0021] The characteristics of the present invention are as follows. In Steps 2 and 3, by adding pentaerythritol and phosphorus trichloride, a substitution reaction occurs to obtain hydroxylated phosphonate; further, by adding hydroxylated phosphonate, p-formylbenzoic acid, 4-dimethylaminopyridine, and N,N-diisopropylcarbodiimide, an esterification reaction occurs to obtain aldehyde-functionalized phosphonate. In Step 3, a Schiff base reaction occurs between the aldehyde-functionalized phosphonate prepared in Step 2 and the remaining amino groups in the flame-retardant polysiloxane to graft the phosphonate structure onto the surface of the cage-shaped amino-functionalized polysiloxane, finally obtaining composite silicone. Among them, in Step 1, by controlling the reaction molar ratio of NH2-POSS to epoxidized cyclotriphosphazene to be 1:(4-5), not only can the epoxidized cyclotriphosphazene be grafted onto the surface of NH2-POSS, but also some amino groups can be retained to participate in the Schiff base reaction in Step 3, thus ensuring the introduction of a phosphonate structure with good flame retardancy. In addition, the epoxidized cyclotriphosphazene surface has multiple epoxy groups. At a reaction molar ratio of NH2-POSS to epoxidized cyclotriphosphazene of 1:(4-5), there will be more remaining epoxy groups. Therefore, after adding polyamide 651 curing agent in Step 3, the composite silicone prepared in the present invention and the main resin epoxy resin will be fully compatible and undergo a chemical cross-linking reaction, forming a more stable cross-linked structure together with the main resin epoxy resin, thereby optimizing the comprehensive performance of the material.

[0022] In summary, the composite silicone prepared in the present invention integrates three elements with excellent flame retardant properties, namely silicon, nitrogen, and phosphorus. The silicon element can form a vitreous protective layer during combustion to delay combustion; the nitrogen element can release nitrogen during combustion to dilute combustible gases and inhibit combustion; the phosphorus element can promote the carbonization process at high temperatures to form a protective carbon layer to isolate oxygen. Through the synergistic effect of these elements, the flame retardant performance is significantly improved, making the coating perform more excellently in fires. In addition, by introducing structures such as siloxanes, the chemical stability, UV resistance, and hydrophobic and corrosion-resistant properties of the finished coating can be significantly improved, thereby ensuring the stable performance of the product in various harsh environments. Detailed implementation manners

[0023] Next, the technical solutions in the present invention will be clearly and completely described in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without making creative efforts shall fall within the protection scope of the present invention.

[0024] Source of raw materials:

[0025] Epoxy resin, provided by Langfang Yushi Anticorrosive Material Co., Ltd., model 6101; dispersant, provided by Shenzhen Longdi Chemical Co., Ltd., model BYK - 2070; leveling agent, provided by BYK Chemie Technical Consulting Co., Ltd., specifically leveling agent BYD - 354, with an industrial grade specification; polyamide 651 curing agent, provided by Beijing Xiangshan United Auxiliary Factory, with an industrial grade specification; in terms of mass parts, one part is 1 g.

[0026] Example 1: Step 1: Dissolve tetraethylammonium hydroxide in a mixed solvent, and then slowly drop 3 - aminopropyltriethoxysilane, and stir and react at 70 °C for 25 h. After the reaction ends, cool at room temperature, precipitate at low temperature, filter, and vacuum dry to obtain NH2 - POSS; the mixed solvent includes deionized water, propanol, and acetonitrile, with a volume ratio of 1:0.4:0.1; the reaction volume ratio of tetraethylammonium hydroxide and 3 - aminopropyltriethoxysilane is 0.5:57;

[0027] Hexachlorocyclotriphosphazene was dissolved in xylene, and ethanolamine was slowly added dropwise under a nitrogen atmosphere. The temperature was slowly raised to 75 °C, and the mixture was stirred and refluxed for 15 h. After the reaction was completed, the bottom liquid was washed, dried, and purified to obtain hydroxylated cyclotriphosphazene; under a nitrogen atmosphere, hydroxylated cyclotriphosphazene, γ-glycidoxypropyltrimethoxysilane, and stannous octoate as a catalyst were mixed, and the temperature was slowly raised to 55 °C and stirred for 10 h to obtain epoxidized cyclotriphosphazene; NH2-POSS was dissolved in xylene, and then epoxidized cyclotriphosphazene was added and ultrasonically dispersed evenly. The temperature was slowly raised to 110 °C and reacted for 3 h to obtain flame-retardant polysiloxane; when preparing hydroxylated cyclotriphosphazene, the reaction molar ratio of hexachlorocyclotriphosphazene to ethanolamine was 1:5.5; when preparing epoxidized cyclotriphosphazene, the reaction molar ratio of hydroxylated cyclotriphosphazene to γ-glycidoxypropyltrimethoxysilane was 1:5.5; when preparing flame-retardant polysiloxane, the reaction molar ratio of NH2-POSS to epoxidized cyclotriphosphazene was 1:4.5;

[0028] Step 2: Under a nitrogen atmosphere, pentaerythritol and phosphorus trichloride were mixed, and the temperature was raised to 95 °C and reacted for 1.5 h, then raised to 150 °C and reacted for 9 h, and then raised to 170 °C and reacted for 1.5 h. After the reaction was completed, it was cooled, extracted, filtered, rotary evaporated, and vacuum dried to obtain hydroxylated phosphonate; hydroxylated phosphonate, p-formylbenzoic acid, and 4-dimethylaminopyridine were dissolved in anhydrous dichloromethane, and then N,N-diisopropylcarbodiimide was added and reacted for 14 h. After the reaction was completed, it was washed with saturated sodium bicarbonate solution, saturated sodium chloride solution, deionized water, dried, and the solvent was removed to obtain aldehyde-functionalized phosphonate; when preparing hydroxylated phosphonate, the reaction molar ratio of pentaerythritol to phosphorus trichloride was 1:1; when preparing aldehyde-functionalized phosphonate, the reaction molar ratio of the hydroxyl group in hydroxylated phosphonate to the carboxyl group in p-formylbenzoic acid was 1:3.5;

[0029] Step 3: Tris hydrochloride was dissolved in deionized water, and the pH was adjusted to 8.5 with sodium hydroxide solution to obtain a 0.5 g / mL Tris buffer solution;

[0030] Aldehyde-functionalized phosphonate and flame-retardant polysiloxane were dissolved in toluene, and then Tris buffer solution was added, and the reaction was carried out at 90 °C for 7 h. After the reaction was completed, it was cooled to room temperature, the lower-layer precipitate was taken for centrifugation, and vacuum dried to obtain composite silicone; 50 g of epoxy resin and 25 g of xylene were mixed evenly, and then 15 g of composite silicone, 8 g of aluminum hydroxide filler, 1 g of dispersant, and 1 g of leveling agent were added. After sufficient ball milling, 25 g of polyamide 651 curing agent was added to obtain the finished product; when preparing composite silicone, the reaction molar ratio of the aldehyde group in aldehyde-functionalized phosphonate to the amino group in flame-retardant polysiloxane was 1.4:1.

[0031] Example 2: Step 1: Dissolve tetraethylammonium hydroxide in a mixed solvent, and then slowly add 3-aminopropyltriethoxysilane dropwise. Stir and react at 65 °C for 23 h. After the reaction is completed, cool at room temperature, precipitate at low temperature, filter, and dry under vacuum to obtain NH2-POSS; the mixed solvent includes deionized water, propanol, and acetonitrile, with a volume ratio of 1:0.4:0.1; the reaction volume ratio of tetraethylammonium hydroxide to 3-aminopropyltriethoxysilane is 0.5:57;

[0032] Dissolve hexachlorocyclotriphosphazene in xylene, slowly add ethanolamine dropwise under a nitrogen atmosphere, slowly heat up to 73 °C, and stir and reflux for 14 h. After the reaction is completed, wash the bottom liquid, dry, and remove impurities to obtain hydroxylated cyclotriphosphazene; under a nitrogen atmosphere, mix hydroxylated cyclotriphosphazene, γ-glycidoxypropyltrimethoxysilane, and catalyst stannous octoate, slowly heat up to 53 °C and stir and react for 9 h to obtain epoxidized cyclotriphosphazene; dissolve NH2-POSS in xylene, then add epoxidized cyclotriphosphazene and disperse evenly by ultrasonic wave, slowly heat up to 105 °C and react for 2.5 h to obtain flame-retardant polysiloxane; when preparing hydroxylated cyclotriphosphazene, the reaction molar ratio of hexachlorocyclotriphosphazene to ethanolamine is 1:5.5; when preparing epoxidized cyclotriphosphazene, the reaction molar ratio of hydroxylated cyclotriphosphazene to γ-glycidoxypropyltrimethoxysilane is 1:5.5; when preparing flame-retardant polysiloxane, the reaction molar ratio of NH2-POSS to epoxidized cyclotriphosphazene is 1:4.5;

[0033] Step 2: Under a nitrogen atmosphere, mix pentaerythritol and phosphorus trichloride sulfide, heat up to 93 °C and react for 1.2 h, then heat up to 145 °C and react for 8 h, and then heat up to 165 °C and react for 1.3 h. After the reaction is completed, cool, extract, filter, spin dry, and dry under vacuum to obtain hydroxylated phosphonate; dissolve hydroxylated phosphonate, p-formylbenzoic acid, and 4-dimethylaminopyridine in anhydrous dichloromethane, then add N,N-diisopropylcarbodiimide and react for 12 h. After the reaction is completed, wash with saturated sodium bicarbonate solution, saturated sodium chloride solution, deionized water, dry, and remove the solvent to obtain aldehyde-functionalized phosphonate; when preparing hydroxylated phosphonate, the reaction molar ratio of pentaerythritol to phosphorus trichloride sulfide is 1:1; when preparing aldehyde-functionalized phosphonate, the reaction molar ratio of the hydroxyl group in hydroxylated phosphonate to the carboxyl group in p-formylbenzoic acid is 1:3.5;

[0034] Step 3: Dissolve tris(hydroxymethyl)aminomethane hydrochloride in deionized water, and then adjust the pH to 8.5 with sodium hydroxide solution to obtain a 0.5 g / mL Tris buffer solution;

[0035] The aldehyde-functionalized phosphonate and flame-retardant polysiloxane are dissolved in toluene, and then Tris buffer solution is added. The reaction is carried out at 85 °C for 6 h. After the reaction is completed, it is cooled to room temperature, the lower-layer precipitate is taken for centrifugation, and vacuum drying is carried out to obtain the composite silicone. 50 g of epoxy resin and 25 g of xylene are mixed evenly, and then 15 g of the composite silicone, 8 g of aluminum hydroxide filler, 1 g of dispersant, and 1 g of leveling agent are added. After sufficient ball milling, 25 g of polyamide 651 curing agent is added to obtain the finished product. When preparing the composite silicone, the molar ratio of the aldehyde group in the aldehyde-functionalized phosphonate to the amino group in the flame-retardant polysiloxane is 1.4:1.

[0036] Example 3: Step 1: Tetraethylammonium hydroxide is dissolved in a mixed solvent, and 3-aminopropyltriethoxysilane is slowly added dropwise. The reaction is stirred at 60 °C for 20 h. After the reaction is completed, it is cooled to room temperature, precipitated at low temperature, filtered, and vacuum dried to obtain NH2-POSS. The mixed solvent includes deionized water, propanol, and acetonitrile, with a volume ratio of 1:0.4:0.1. The reaction volume ratio of tetraethylammonium hydroxide to 3-aminopropyltriethoxysilane is 0.5:57.

[0037] Hexachlorocyclotriphosphazene is dissolved in xylene, and ethanolamine is slowly added dropwise under a nitrogen atmosphere. The temperature is slowly raised to 70 °C, and the reaction is stirred and refluxed for 12 h. After the reaction is completed, the bottom liquid is washed, dried, and purified to obtain hydroxylated cyclotriphosphazene. Under a nitrogen atmosphere, hydroxylated cyclotriphosphazene, γ-glycidoxypropyltrimethoxysilane, and catalyst stannous octoate are mixed, and the temperature is slowly raised to 50 °C and stirred for 8 h to obtain epoxidized cyclotriphosphazene. NH2-POSS is dissolved in xylene, and then epoxidized cyclotriphosphazene is added and ultrasonically dispersed evenly. The temperature is slowly raised to 100 °C and the reaction is carried out for 2 h to obtain the flame-retardant polysiloxane. When preparing hydroxylated cyclotriphosphazene, the molar ratio of hexachlorocyclotriphosphazene to ethanolamine is 1:5.5. When preparing epoxidized cyclotriphosphazene, the molar ratio of hydroxylated cyclotriphosphazene to γ-glycidoxypropyltrimethoxysilane is 1:5.5. When preparing the flame-retardant polysiloxane, the molar ratio of NH2-POSS to epoxidized cyclotriphosphazene is 1:4.5.

[0038] Step 2: Under a nitrogen atmosphere, pentaerythritol and phosphorus trichloride are mixed, heated to 90 °C and reacted for 1.0 h, then heated to 140 °C and reacted for 7 h, and then heated to 160 °C and reacted for 1.0 h. After the reaction is completed, it is cooled, extracted, filtered, rotary evaporated, and vacuum dried to obtain hydroxylated phosphonate; the hydroxylated phosphonate, p-formylbenzoic acid, and 4-dimethylaminopyridine are dissolved in anhydrous dichloromethane, and then N,N-diisopropylcarbodiimide is added and reacted for 10 h. After the reaction is completed, it is washed with saturated sodium bicarbonate solution, saturated sodium chloride solution, deionized water, dried, and the solvent is removed to obtain aldehyde-functionalized phosphonate; when preparing hydroxylated phosphonate, the reaction molar ratio of pentaerythritol to phosphorus trichloride is 1:1; when preparing aldehyde-functionalized phosphonate, the reaction molar ratio of the hydroxyl group in hydroxylated phosphonate to the carboxyl group in p-formylbenzoic acid is 1:3.5;

[0039] Step 3: Dissolve tris(hydroxymethyl)aminomethane hydrochloride in deionized water, and then adjust the pH to 8.5 with sodium hydroxide solution to obtain a 0.5 g / mL Tris buffer solution;

[0040] Dissolve the aldehyde-functionalized phosphonate and flame-retardant polysiloxane in toluene, then add the Tris buffer solution, and react at 80 °C for 5 h. After the reaction is completed, it is cooled to room temperature, the lower-layer precipitate is taken out and centrifuged, and vacuum dried to obtain composite organosilicon; mix 50 g of epoxy resin and 25 g of xylene evenly, then add 15 g of composite organosilicon, 8 g of aluminum hydroxide filler, 1 g of dispersant, and 1 g of leveling agent, and after sufficient ball milling, add 25 g of polyamide 651 curing agent to obtain the finished product; when preparing composite organosilicon, the reaction molar ratio of the aldehyde group in aldehyde-functionalized phosphonate to the amino group in flame-retardant polysiloxane is 1.4:1.

[0041] Comparative Example 1: Remove Step 1: Preparation of flame-retardant polysiloxane, and the rest is the same as Example 1. The specific steps are as follows: Step 1: Under a nitrogen atmosphere, pentaerythritol and phosphorus trichloride are mixed, heated to 93 °C and reacted for 1.2 h, then heated to 145 °C and reacted for 8 h, and then heated to 165 °C and reacted for 1.3 h. After the reaction is completed, it is cooled, extracted, filtered, rotary evaporated, and vacuum dried to obtain hydroxylated phosphonate; the hydroxylated phosphonate, p-formylbenzoic acid, and 4-dimethylaminopyridine are dissolved in anhydrous dichloromethane, and then N,N-diisopropylcarbodiimide is added and reacted for 14 h. After the reaction is completed, it is washed with saturated sodium bicarbonate solution, saturated sodium chloride solution, deionized water, dried, and the solvent is removed to obtain aldehyde-functionalized phosphonate; when preparing hydroxylated phosphonate, the reaction molar ratio of pentaerythritol to phosphorus trichloride is 1:1; when preparing aldehyde-functionalized phosphonate, the reaction molar ratio of the hydroxyl group in hydroxylated phosphonate to the carboxyl group in p-formylbenzoic acid is 1:3.5;

[0042] Step 2: Mix 50 g of epoxy resin and 25 g of xylene evenly, then add 15 g of aldehyde-phosphonate, 8 g of aluminum hydroxide filler, 1 g of dispersant, and 1 g of leveling agent. After thorough ball milling, add 25 g of polyamide 651 curing agent to obtain the finished product.

[0043] Comparative Example 2: Remove the preparation of aldehyde-phosphonate in Step 2, and the rest is the same as in Example 1. The specific steps are as follows: Step 1: Dissolve tetraethylammonium hydroxide in a mixed solvent, then slowly dropwise add 3-aminopropyltriethoxysilane, and stir and react at 70 °C for 25 h. After the reaction is completed, cool at room temperature, precipitate at low temperature, filter, and vacuum dry to obtain NH2-POSS; the mixed solvent includes deionized water, propanol, and acetonitrile, with a volume ratio of 1:0.4:0.1; the reaction volume ratio of tetraethylammonium hydroxide and 3-aminopropyltriethoxysilane is 0.5:57;

[0044] Dissolve hexachlorocyclotriphosphazene in xylene, slowly dropwise add ethanolamine under a nitrogen atmosphere, slowly heat up to 75 °C, and stir and reflux for 15 h. After the reaction is completed, wash, dry, and remove impurities from the bottom liquid to obtain hydroxylated cyclotriphosphazene; under a nitrogen atmosphere, mix hydroxylated cyclotriphosphazene, γ-glycidoxypropyltrimethoxysilane, and catalyst stannous octoate, slowly heat up to 55 °C and stir and react for 10 h to obtain epoxidized cyclotriphosphazene; dissolve NH2-POSS in xylene, then add epoxidized cyclotriphosphazene and disperse evenly by ultrasonic wave, slowly heat up to 110 °C and react for 3 h to obtain flame-retardant polysiloxane; when preparing hydroxylated cyclotriphosphazene, the reaction molar ratio of hexachlorocyclotriphosphazene and ethanolamine is 1:5.5; when preparing epoxidized cyclotriphosphazene, the reaction molar ratio of hydroxylated cyclotriphosphazene and γ-glycidoxypropyltrimethoxysilane is 1:5.5; when preparing flame-retardant polysiloxane, the reaction molar ratio of NH2-POSS and epoxidized cyclotriphosphazene is 1:4.5;

[0045] Step 2: Mix 50 g of epoxy resin and 25 g of xylene evenly, then add 15 g of flame-retardant polysiloxane, 8 g of aluminum hydroxide filler, 1 g of dispersant, and 1 g of leveling agent. After thorough ball milling, add 25 g of polyamide 651 curing agent to obtain the finished product.

[0046] Comparative Example 3: Remove the preparation of composite silicone, and the rest is the same as in Example 1. The specific steps are as follows: Step 1: Mix 50 g of epoxy resin and 25 g of xylene evenly, then add 8 g of aluminum hydroxide filler, 1 g of dispersant, and 1 g of leveling agent. After thorough ball milling, add 25 g of polyamide 651 curing agent to obtain the finished product.

[0047] Flammability test: Coat the finished product paint prepared in the present invention on the surface of the substrate as a specimen, and test the flammability according to the UL-94 vertical burning test standard.

[0048] Weather resistance test: The finished coating prepared by the present invention was applied to the surface of the substrate as a specimen. The weather resistance of the specimen was tested according to ASTM G154 standard for 850 h, and the surface of the specimen was observed to judge the weather resistance of the specimen.

[0049] Contact angle test: The finished coating prepared by the present invention was applied to the surface of the substrate as a specimen. The contact angle between the surface of the specimen and water was measured using a contact angle tester of Guangdong Dayinte Intelligent Technology Co., Ltd. to judge the hydrophobic ability of the surface of the specimen. The results are shown in the following table:

[0050]

[0051] Conclusion: The dosages of Examples 1 to 3 remain unchanged, and only some reaction parameters are modified. From the experimental data, it can be seen that the various properties of the specimens do not show obvious fluctuations.

[0052] Comparative Example 1: Step 1: The preparation of flame-retardant polysiloxane was removed, and the rest was the same as in Example 1. From the experimental data, it can be seen that compared with Example 1, the flame-retardant grade became V-1, and the effect of ultraviolet light aging resistance was that there were multiple powdering and color changes on the surface of the specimen, and the contact angle decreased to 86°. The reason for the analysis is as follows: The flame-retardant polysiloxane prepared by the present invention can significantly improve the flame-retardant performance through the synergistic effect of multiple flame-retardant elements; a large number of siloxane structures in the flame-retardant polysiloxane can effectively resist the erosion of environmental factors such as humidity and heat due to its excellent chemical stability, and at the same time significantly improve the hydrophobic performance of the sample surface; therefore, after removing the preparation of flame-retardant polysiloxane, the flame retardancy, weather resistance, and hydrophobicity decreased.

[0053] Comparative Example 2: Step 2: The preparation of aldehyde-phosphonate was removed, and the rest was the same as in Example 1. From the experimental data, it can be seen that compared with Example 1, the flame-retardant grade became V-1. The reason for the analysis is as follows: The aldehyde-phosphonate contains a phosphonate flame-retardant structure, which can decompose at high temperature and form low-volatile phosphorus oxides, promoting the formation of a stable char layer on the surface of the material to prevent the spread of flames; therefore, after removing the preparation of aldehyde-phosphonate, the flame retardancy decreased.

[0054] Comparative Example 3: The preparation of composite silicone was removed, and the rest was the same as in Example 1. From the experimental data, it can be seen that compared with Example 1, the flame-retardant grade became V-2, and the effect of ultraviolet light aging resistance was that the specimen surface was severely powdered and significantly discolored, and the contact angle decreased to 81°. The reason for the analysis is as follows: The composite silicone was prepared by the reaction of flame-retardant polysiloxane and aldehyde-phosphonate. Therefore, this material can combine the properties of the two materials to obtain a composite silicone material with good flame retardancy, weather resistance, and hydrophobicity; so after removing the preparation of composite silicone, the flame retardancy, weather resistance, and hydrophobicity decreased.

[0055] It should be noted that in this text, relational terms such as first and second are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any actual relationship or order between these entities or operations. Moreover, the terms "comprising", "including" or any other variation thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device comprising a series of elements not only includes those elements, but also includes other elements not expressly listed, or elements inherent to such process, method, article or device.

[0056] Finally, it should be noted that the above are only preferred embodiments of the present invention and are not used to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or perform equivalent replacements for some of the technical features. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present invention shall be included within the protection scope of the present invention.

Claims

1. A process for preparing a high-performance, corrosion-resistant, and environmentally friendly coating, characterized by: The following steps are involved: Step 1: dissolving hexachlorocyclotriphosphazene in xylene, slowly adding ethanolamine dropwise under a nitrogen environment, slowly heating to 70-75°C, stirring and reflux reacting for 12-15 hours, and washing, drying, and removing impurities from the bottom liquid after the reaction to obtain hydroxylated cyclotriphosphazene; under a nitrogen environment, mixing hydroxylated cyclotriphosphazene, γ-glycidyloxypropyltrimethoxysilane, and catalyst stannous octoate, slowly heating to 50-55°C, stirring and reacting for 8-10 hours to obtain epoxidized cyclotriphosphazene; dissolving NH2-POSS in xylene, then adding epoxidized cyclotriphosphazene and ultrasonically dispersing it evenly, slowly heating to 100-110°C and reacting for 2-3 hours to obtain flame-retardant polysiloxane; Step 2: Under a nitrogen environment, tetrapentanol and trichlorophosphorus are mixed, heated to 90-95° C. for reaction for 1.0-1.5 hours, then heated to 140-150° C. for reaction for 7-9 hours, and then heated to 160-170° C. for reaction for 1.0-1.5 hours. After the reaction, the mixture is cooled, extracted, filtered, spin-dried, and vacuum-dried to obtain a hydroxylated phosphonate; the hydroxylated phosphonate, p-formylbenzoic acid, and 4-dimethylaminopyridine are dissolved in anhydrous dichloromethane, and N, N-diisopropylcarbodiimide is added and reacted for 10-14 hours. After the reaction, the mixture is washed with saturated sodium bicarbonate solution, saturated sodium chloride solution, deionized water, dried, and the solvent is removed to obtain an aldehyded phosphonate; Step 3: Dissolve the formaldehyde-modified phosphonate and flame-retardant polysiloxane in toluene, add Tris buffer, react at 80-90°C for 5-7h, cool to room temperature after the reaction, remove the precipitate, centrifuge, and vacuum dry to obtain a composite silicone; mix the epoxy resin and xylene evenly, add the composite silicone, aluminum hydroxide filler, dispersant, and leveling agent, fully ball-mill, and then add polyamide 651 curing agent to obtain the finished product.

2. The process for preparing a high-performance, corrosion-resistant, and environmentally friendly coating according to claim 1, wherein: In step 1, when preparing hydroxylated cyclotriphosphazene, the reaction molar ratio of hexachlorocyclotriphosphazene and ethanolamine is 1:(5-6).

3. The process for preparing a high-performance, corrosion-resistant, and environmentally friendly coating according to claim 1, wherein: In step 1, when preparing epoxidized cyclotriphosphazene, the reaction molar ratio of hydroxylated cyclotriphosphazene and γ-glycidyloxypropyltrimethoxysilane is 1:(5-6).

4. The process for preparing a high-performance, corrosion-resistant, and environmentally friendly coating according to claim 1, wherein: In step 1, when preparing the flame-retardant polysiloxane, the reaction molar ratio of NH2-POSS and epoxidized cyclotriphosphazene is 1:(4-5).

5. The process for preparing a high-performance, corrosion-resistant, and environmentally friendly coating according to claim 4, wherein: The preparation process of NH2-POSS is as follows: tetraethylammonium hydroxide is dissolved in a mixed solvent, 3-aminopropyltriethoxysilane is slowly added dropwise, and the mixture is stirred and reacted at 60-70°C for 20-25 hours. After the reaction is completed, the mixture is cooled to room temperature, precipitated at low temperature, filtered, and vacuum dried to obtain NH2-POSS; the mixed solvent includes deionized water, propanol, and acetonitrile in a volume ratio of 1:0.4:0.1; the reaction volume ratio of tetraethylammonium hydroxide and 3-aminopropyltriethoxysilane is 0.5:(55-60).

6. The process for preparing a high-performance, corrosion-resistant, and environmentally friendly coating according to claim 1, wherein: When preparing hydroxylated phosphonic acid esters, the reaction molar ratio of tetrapentanol and trichlorophosphorus is 1:(1.0-1.2).

7. The process for preparing a high-performance, corrosion-resistant, and environmentally friendly coating according to claim 1, wherein: In step 2, when preparing the formaldehyde-phosphonate, the reaction molar ratio of the hydroxyl group in the hydroxylated phosphonate to the carboxyl group in the p-formaldehyde benzoic acid is 1:(3-4).

8. The process for preparing a high-performance, corrosion-resistant, and environmentally friendly coating according to claim 1, wherein: In step 3, tris (hydroxymethyl)aminomethane hydrochloride) is dissolved in deionized water, and then the pH is adjusted to 8.5-9.0 using sodium hydroxide solution to obtain 0.5-0.6 g / mL Tris buffer.

9. The process for preparing a high-performance, corrosion-resistant, and environmentally friendly coating according to claim 1, wherein: In step 3, when preparing the composite organosilicon, the reaction molar ratio of the aldehyde group in the formaldehyde-formylated phosphonate and the amino group in the flame-retardant polysiloxane is (1.3-1.5):

1.

10. The process for preparing a high-performance, corrosion-resistant, and environmentally friendly coating according to claim 1, wherein: In step three, the contents of the components of the epoxy coating are: by mass, 50-60 parts of epoxy resin, 25-30 parts of xylene, 13-18 parts of composite silicone, 8-10 parts of aluminum hydroxide filler, 1-2 parts of dispersant, 1-2 parts of leveling agent, and 25-30 parts of polyamide 651 curing agent.

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