Multifunctional organic silicon coating and preparation method thereof

Abstract

The invention relates to the technical field of organic silicon materials and surface protection, and discloses a multifunctional organic silicon coating and a preparation method thereof.The coating is prepared from, by mass, 200-400 parts of alpha, omega-hydroxyl-terminated polydimethylsiloxane, 200-400 parts of alpha, omega-hydroxyl-terminated polydimethylsiloxane, 200-400 parts of alpha, omega-hydroxyl-terminated polydimethylsiloxane, 200-400 parts of alpha, omega-hydroxyl-terminated The flame-retardant silicone rubber is prepared from the following components in parts by weight: 150 to 200 parts of alpha, omega-hydroxyl-terminated polyphenyl siloxane, 20 to 50 parts of nano SiO2 powder, 100 to 200 parts of flame-retardant powder, 80 to 150 parts of conventional powder, 15 to 30 parts of a cross-linking agent, 5 to 10 parts of a coupling agent, 0.3 to 0.8 part of a catalyst, 5 to 15 parts of an amine small-molecular auxiliary agent and 100 to 200 parts of a solvent. The flame-retardant and environment-friendly inorganic powder is used, the coating is endowed with a flame-retardant function, the long-chain amine small-molecule auxiliary is introduced, and a double anti-corrosion mechanism of chemical slow neutralization and physical barrier is formed by combining a hydrophobic barrier of alpha, omega-hydroxyl-terminated polyphenylsiloxane and compact physical protection of the nano powder; the prepared coating has the advantages of flame retardance, acid and alkali corrosion resistance, ash adhesion resistance, good strength and elasticity, weather aging resistance and easiness in construction, and is suitable for protection and decoration of metal base materials and building concrete structures.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silicone materials and surface protection, in particular to a multifunctional silicone coating with flame-retardant, anticorrosive and dust-proof properties and a preparation method thereof. BACKGROUND

[0002] With the rapid development of modern industrial fields and construction industries, new requirements are put forward for the strength and service life of materials. The use of coatings not only provides good protection for the substrate, but also has a decorative function. Traditional coatings generally have the disadvantages of insufficient flexibility, poor weather resistance, and narrow temperature resistance range (-20℃-120℃). CN116535655B discloses a method for preparing an anticorrosive coating using epoxy resin, and the elongation at break is only 13.61%, which cannot cope with the deformation of the substrate, and is prone to cracking and failure after long-term use. Silicone coatings are based on their unique chemical structure (Si-O-Si as the main chain, and organic groups connected to the side chain), which gives the coating good flexibility and elasticity, can adapt to the thermal expansion and contraction of the substrate and a certain degree of deformation without cracking, and the surface energy is low, which can prevent corrosive media from wetting, penetrating and adhering to the coating surface, physically isolating the substrate from the corrosive environment, making it the preferred protective material in extreme or harsh environments such as corrosion and outdoor aging.

[0003] At the same time, silicone resins themselves have good intrinsic flame retardance, and compared with organic polymer materials, silicone produces less smoke and toxic gases (such as carbon monoxide, hydrogen cyanide, etc.) when burning, meeting the requirements of fire safety and environmental protection. By adding specific flame-retardant ingredients (ammonium polyphosphate, expandable graphite, aluminum / magnesium hydroxide, etc.), the flame-retardant grade can be further improved to meet higher fire safety standards.

[0004] However, developing multifunctional organosilicon coatings is a major challenge. Powders such as aluminum hydroxide and magnesium hydroxide are environmentally friendly, non-toxic, and relatively inexpensive, making them suitable for large-scale industrial production. Patent CN119192997A discloses a method for preparing organosilicon flame-retardant coatings using powders such as aluminum hydroxide, but does not provide an overview of other performance evaluations. Using powders such as aluminum hydroxide and magnesium hydroxide in combination with an organosilicon rubber film-forming material is a low-cost and cost-effective method for producing flame-retardant coatings. However, these commonly used flame-retardant powders, as well as some other powders such as calcium carbonate and wollastonite, are prone to reaction in acidic environments, resulting in coating cavitation, cavitation, and powdering. However, methods that exclusively use other acid-resistant powders such as silica powder and barium sulfate to prepare organosilicon anti-corrosion coatings limit formulation design, making it difficult to achieve coatings with ideal mechanical and flame-retardant properties (e.g., patents CN111471395B and CN113861838B). At the same time, acid-resistant powders require large amounts to provide effective protection. Some powders, due to their high density, can cause sedimentation during storage, impacting the coating's performance. Therefore, finding a more effective solution to the poor acid resistance of silicone rubber coatings, often caused by powders, remains an industry challenge. Furthermore, in an alkaline environment, the silicone backbone, composed of alternating silicon and oxygen atoms, will be attacked by OH- atoms in the Si-O-Si bond, breaking the bond and forming silicon alkoxides (Si-Na) and silanols (Si-OH). This ultimately degrades the backbone, leading to decreased mechanical properties such as loss of elasticity and embrittlement. Organic side groups, such as methyl groups, can undergo dealkylation in strong bases, attacking the original Si-CH3 groups to form Si-OH groups, ultimately causing the coating to powder and fail. If the silicone rubber has a low degree of crosslinking, prolonged immersion in the silicone rubber allows the alkaline solution to penetrate the crosslinked network, causing the coating to swell and accelerate the coating's failure. CN116463052B and CN116376375A disclose methods for improving liquid resistance by using fluorine-modified silicone rubber. However, fluorine-containing products are expensive and require complex preparation processes, which are not environmentally friendly. Consequently, silicone coatings also face the challenge of poor alkali resistance.

[0005] Furthermore, the silicone backbone consists of a silicon-oxygen bond, with methyl groups as side chains. Processing or environmental factors can break these bonds, forming surface hydroxyl groups. The high electronegativity of oxygen atoms and the low polarizability of methyl groups exacerbate charge localization, leading to a high surface charge on the coating that attracts positively charged dust particles. Consequently, silicone coatings are prone to dust attraction and difficult to clean. Modifying the coating's surface structure to improve its dust resistance is another challenge facing this material.

[0006] Therefore, developing a silicone coating that has high efficiency flame retardancy, good dust resistance and long-term substrate protection (corrosion resistance and weather resistance), as well as good construction performance and reasonable cost is a development difficulty in this field, but it also has important application value and broad prospects for use. Summary of the Invention

[0007] The present invention aims to provide a multifunctional organic silicon coating and a preparation method thereof, aiming to take into account the flame retardancy, dust resistance and acid and alkali corrosion resistance of the organic silicon coating.

[0008] To achieve the above-mentioned purpose, the present invention adopts the following technical scheme: a multifunctional silicone coating, whose raw materials, calculated by mass, include 200-400 parts of α,ω-terminated hydroxyl polydimethylsiloxane, 150-200 parts of α,ω-terminated hydroxyl polyphenylsiloxane, 20-50 parts of nano-SiO2 powder, 100-200 parts of flame retardant powder, 80-150 parts of conventional powder, 15-30 parts of crosslinking agent, 5-10 parts of coupling agent, 0.3-0.8 parts of catalyst, 5-15 parts of amine small molecule additive, and 100-200 parts of solvent, and the α,ω-terminated hydroxyl polydimethylsiloxane is a multi-viscosity mixture. Preferably, as an improvement, the α,ω-hydroxy-terminated polydimethylsiloxane is prepared by mixing α,ω-hydroxy-terminated polydimethylsiloxanes with viscosities of 80,000 mPa.s, 10,000 mPa.s, and 1,500 mPa.s in a mass ratio of 2:3:3.

[0009] Preferably, as an improvement, the viscosity of the α,ω-hydroxy-terminated polyphenylsiloxane is 10000 mPa·s.

[0010] Preferably, as an improvement, the particle size D50 of the nano-SiO2 powder is ≤ 100 nm, and the specific surface area is ≥ 200 m 2 / g.

[0011] Preferably, as an improvement, the flame retardant powder is at least one of aluminum hydroxide and magnesium hydroxide.

[0012] Preferably, as an improvement, the conventional powder is at least one of active nano-calcium carbonate and wollastonite; the D50 of the active nano-calcium carbonate is 500 nm, and the mesh size of the wollastonite is 2000 mesh.

[0013] Preferably, as an improvement, the crosslinking agent is at least one of tetrabutyl ketoxime silane, methyl tributyketoxime silane, vinyl tributyketoxime silane, and methyl triacetoneoxime silane; Preferably, as an improvement, the coupling agent is at least two of aminopropyltriethoxysilane, glycidyloxypropyltrimethoxysilane, methacryloxypropyltrimethoxysilane, vinyltriethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, octyltriethoxysilane, ureapropyltriethoxysilane, diethylaminomethyltriethoxysilane, and n-octyltriethoxysilane.

[0014] Preferably, as an improvement, the catalyst is at least one of dibutyltin dilaurate, dialkyltin dihydroxyate, dialkyldiaryloxytin, and stannous dihydroxyate; the amine small molecule auxiliary agent is at least one of diundecylamine, didodecylamine, dioctadecylamine, octadecylamine, and N,N ditetradecylamine; and the solvent is D30 solvent oil.

[0015] Preferably, as an improvement, a multifunctional organosilicon coating and a preparation method thereof include the following steps: S1. After stirring α,ω-hydroxy-terminated polydimethylsiloxane, α,ω-hydroxy-terminated polyphenylsiloxane, nano-SiO2 powder, flame retardant powder, and conventional powder, kneading under heating and vacuum conditions to obtain a base material, and cooling to room temperature for use; S2. Add the base material cooled to room temperature and the cross-linking agent, coupling agent, catalyst, and amine small molecule additive into a blender, stir evenly under vacuum, add solvent oil, and stir and mix to obtain the silicone elastic anti-corrosion coating.

[0016] Preferably, as an improvement, in step S1, the heating temperature is 140°C, the vacuum degree is ≥0.085 MPa, and the kneading time is 3 hours; in step S2, the vacuum stirring time is 50 minutes.

[0017] The principles and advantages of this solution are: in actual application, in this technical solution, in response to the problems existing in the existing technical routes, through reasonable regulation of the formula, a single-component silicone coating with flame retardancy, good acid and alkali corrosion resistance, dust resistance, weather resistance and good strength and elasticity suitable for metal substrates and building concrete structures in harsh environments is prepared.

[0018] In the optimization of the formula, this technical solution selects aluminum hydroxide and magnesium hydroxide as flame retardant powders. Aluminum hydroxide, magnesium hydroxide, etc. can release water vapor to dilute oxygen and combustible gases through endothermic decomposition at 200-400°C, and form aluminum oxide and magnesium oxide diaphragms after decomposition, which play the role of heat insulation and gas isolation, giving the coating good flame retardant effect. It is environmentally friendly, non-toxic and inexpensive.

[0019] In order to solve the problem of poor acid resistance of flame retardant powders such as aluminum hydroxide, magnesium hydroxide and auxiliary powders such as nano calcium carbonate and wollastonite in coatings, specific long-chain alkylamines are added to the formula as "sacrificial protective agents". + At the same time, the long-chain alkyl further reduces the surface energy of the coating due to its low surface energy and hydrophobicity. The synergistic effect of the two significantly reduces the overall surface energy of the coating, making it more repellent to acidic corrosive liquids.

[0020] To address the alkali resistance of silicone molecular chains, this technical solution uses nano-SiO2 powder to form a three-dimensional network structure within the silicone rubber structure through hydrogen bonds and van der Waals forces, creating a strong interaction with the silicone rubber molecular chains and protecting the main chain of the silicone molecules. Polydimethylsiloxanes of different viscosities synergistically cure with polyphenylsiloxanes, with low-viscosity polydimethylsiloxane filling the pores and high-viscosity polydimethylsiloxane forming the skeleton, resulting in a dense and flexible gradient structure. The high cross-linking density and rigid benzene ring structure protect the side groups of the silicone molecules from alkali corrosion. At the same time, the synergistic hydrophobic function of long-chain amine small molecule additives and polydimethylsiloxane, as well as the dense coating structure, make it more shielded against alkali solutions and further enhance the coating's resistance to alkali corrosion.

[0021] Furthermore, long-chain alkylamine small molecule additives are more concentrated on the coating surface due to the polarity difference between the two in the organosilicon system. Their stronger polarity compared to organosilicon molecules helps eliminate the localization of surface charge, thereby improving the electrostatic dust absorption effect. Furthermore, the low surface energy and strong hydrophobicity brought by long-chain amine small molecules also facilitate the removal of dust particles. The strong hydrophobicity can block the formation of water films and inhibit capillary adsorption between water vapor in the air, dust, and the coating. Therefore, this coating has excellent dust-repellent properties.

[0022] In addition, this solution adjusts the fluidity and elasticity of the system by compounding polydimethylsiloxanes of various viscosities and utilizing the entanglement effect of segments with different molecular weights; high-viscosity segments provide a strength basis, and low-viscosity segments improve processability, forming a uniform network skeleton after compounding to enhance the flexibility and deformation resistance of the coating; utilizing the coordinated use of multiple cross-linking agents to form a dense cross-linked network, and the synergistic reinforcement of nano-SiO2 powder and nano-activated calcium carbonate to give the coating good strength and elasticity.

[0023] In summary, the beneficial effects of this technical solution are: 1. In this technical solution, by compounding multi-viscosity base glue with a variety of powders, the coating has flame retardant function, good strength and elasticity, can achieve fire protection and adapt to the thermal expansion and contraction deformation of the substrate.

[0024] 2. This technical solution addresses the powder's acid resistance through chemical neutralization using long-chain amine small molecule additives, breaking through existing technical barriers. The synergistic combination of "nano-SiO2 powder + α,ω-hydroxyl-terminated polyphenylsiloxane + long-chain amine small molecule additives" enhances the silicone coating's interfacial protection and addresses the poor alkali resistance of traditional silicone coatings.

[0025] 3. In this technical solution, long-chain amine small molecules are used to simultaneously achieve good dust-free performance of the coating.

[0026] 4. In this technical solution, through the multi-dimensional route of "molecular structure design - powder interface optimization - functional additive synergy", a single-component silicone coating system with flame retardancy, acid and alkali corrosion resistance, and dust resistance is constructed, which solves the contradiction between different functional implementations and provides a new technical path for the long-term protection of metal substrates and building concrete structures. DETAILED DESCRIPTION

[0027] The following is further described in detail through specific embodiments, but the embodiments of the present invention are not limited thereto. Unless otherwise specified, the technical means used in the following embodiments are conventional means well known to those skilled in the art; the experimental methods used are all conventional methods; and the materials, reagents, etc. used are all commercially available.

[0028] Program Overview: A multifunctional organosilicon coating comprises, by weight, 200-400 parts of α,ω-hydroxyl-terminated polydimethylsiloxane, 150-200 parts of α,ω-hydroxyl-terminated polyphenylsiloxane, 20-50 parts of nano-SiO2 powder, 100-200 parts of flame retardant powder, 80-150 parts of conventional powder, 15-30 parts of a crosslinking agent, 5-10 parts of a coupling agent, 0.3-0.8 parts of a catalyst, 5-15 parts of an amine small molecule additive, and 100-200 parts of a solvent.

[0029] The α,ω-terminated hydroxyl polydimethylsiloxane is prepared by mixing α,ω-terminated hydroxyl polydimethylsiloxanes with viscosities of 80000 mPa.s, 10000 mPa.s, and 1500 mPa.s in a mass ratio of 2:3:3.

[0030] The viscosity of α,ω-hydroxy-terminated polyphenylsiloxane is 10000 mPa.s.

[0031] The particle size of nano-SiO2 powder is D50≤100nm, and the specific surface area is ≥200m 2 / g.

[0032] The flame retardant powder is at least one of aluminum hydroxide and magnesium hydroxide.

[0033] The conventional powder is at least one of active nano-calcium carbonate and wollastonite; the D50 of the active nano-calcium carbonate is 500 nm, and the mesh number of the wollastonite is 2000 mesh.

[0034] The crosslinking agent is at least one of tetrabutyl ketoxime silane, methyltributyketoxime silane, vinyltributyketoxime silane and methyltriacetoneoxime silane.

[0035] The coupling agent is a silane coupling agent, specifically at least two of aminopropyltriethoxysilane, glycidyloxypropyltrimethoxysilane, methacryloxypropyltrimethoxysilane, vinyltriethoxysilane, methyltrimethoxysilane, vinyltrimethoxysilane, octyltriethoxysilane, ureapropyltriethoxysilane, diethylaminomethyltriethoxysilane, and n-octyltriethoxysilane.

[0036] The catalyst is at least one of dibutyltin dilaurate, dialkyltin dihydroxyate, dialkyldiaryloxytin, and stannous dihydroxyate.

[0037] The amine small molecule auxiliary agent is at least one of diundecylamine, didodecylamine, dioctadecylamine, octadecylamine, and N,N ditetradecylamine.

[0038] The solvent is D30 solvent oil.

[0039] A method for preparing a multifunctional organosilicon coating comprises the following steps: S1. Add α,ω-hydroxyl-terminated polydimethylsiloxane, α,ω-hydroxyl-terminated polyphenylsiloxane, nano-SiO2 powder, flame retardant powder, and conventional powder into a low-speed vacuum mixer, knead for 3 hours under heating (high temperature of 140°C) and vacuum (≥0.085Mpa) conditions to obtain a base material, and cool to room temperature for use; S2. Add the base material cooled to room temperature and the cross-linking agent, coupling agent, catalyst, and amine small molecule additive into a medium-speed mixer, stir in a vacuum for 50 minutes, stir evenly, add solvent oil, stir for 20 minutes, and obtain the silicone elastic anti-corrosion coating.

[0040] Example 1 A method for preparing a multifunctional organosilicon coating comprises the following steps: S1, 90 g of 80000 mPa.s α,ω-terminated hydroxyl polydimethylsiloxane, 135 g of 10000 mPa.s α,ω-terminated hydroxyl polydimethylsiloxane, 135 g of 1500 mPa.s α,ω-terminated hydroxyl polydimethylsiloxane, 180 g of α,ω-terminated hydroxyl polyphenylsiloxane, 35 g of nano-SiO2 powder, 75 g of aluminum hydroxide, 75 g of magnesium hydroxide, 50 g of active nano-calcium carbonate, and 50 g of wollastonite were added to a low-speed vacuum mixer, and the mixture was kneaded under heating (high temperature of 140°C) and vacuum (≥0.085 MPa) for 3 h to obtain a base material, and then cooled to room temperature; S2. Add the base material cooled to room temperature and the cross-linking agent 10g of methyltributylanoxime silane, 8g of vinyltributylanoxime silane, 2g of coupling agent aminopropyltriethoxysilane, 3g of glycidyloxypropyltrimethoxysilane, 2g of vinyltrimethoxysilane, 0.5g of catalyst dibutyltin dilaurate, and 10g of octadecylamine into a medium-speed mixer, stir in vacuum for 50 minutes, stir evenly, add 150g of D30 solvent oil, stir for 20 minutes and mix to obtain the silicone elastic anti-corrosion coating.

[0041] Example 2 A method for preparing a multifunctional organosilicon coating comprises the following steps: S1, 100 g of 80,000 mPa.s α,ω-terminated hydroxyl polydimethylsiloxane, 150 g of 10,000 mPa.s α,ω-terminated hydroxyl polydimethylsiloxane, 150 g of 1500 mPa.s α,ω-terminated hydroxyl polydimethylsiloxane, 200 g of α,ω-terminated hydroxyl polyphenylsiloxane, 50 g of nano-SiO2 powder, 200 g of magnesium hydroxide, and 150 g of active nano-calcium carbonate were added to a low-speed vacuum mixer, and the mixture was kneaded for 3 h under heating (high temperature of 120°C) and vacuum (≥0.085 MPa) to obtain a base material, and then cooled to room temperature; S2. Add the base material cooled to room temperature and the cross-linking agent tetrabutyl ketoxime silane 15g, methyl tributyl ketoxime silane 15g, coupling agent aminopropyl triethoxysilane 2g, vinyl trimethoxysilane 6g, octyl triethoxysilane 2g, diethylamino methyl triethoxysilane 2g, catalyst dialkyl diaryloxy tin 0.8g, and didodecylamine 15g into a medium-speed mixer, and stir in vacuum for 60min. After stirring evenly, add 200g of D30 solvent oil and stir for 20min to obtain the silicone coating.

[0042] Example 3 A method for preparing a multifunctional organosilicon coating comprises the following steps: S1, 50 g of 80000 mPa.s α, ω-terminated hydroxyl polydimethylsiloxane, 75 g of 10000 mPa.s α, ω-terminated hydroxyl polydimethylsiloxane, 75 g of 1500 mPa.s α, ω-terminated hydroxyl polydimethylsiloxane, 150 g of α, ω-terminated hydroxyl polyphenylsiloxane, 20 g of nano-SiO2 powder, 100 g of aluminum hydroxide, and 80 g of active nano-calcium carbonate were added to a low-speed vacuum mixer, and the mixture was kneaded for 3 h under heating (high temperature of 120°C) and vacuum (≥0.085 MPa) to obtain a base material, and then cooled to room temperature; S2. Add the base material cooled to room temperature and 15 g of methyl triacetone oxime silane, a cross-linking agent, 2 g of methacryloyloxypropyl trimethoxysilane, 3 g of ureapropyl triethoxysilane, 0.2 g of stannous dihydroxy acid catalyst, and 7 g of N,N-ditetradecylamine into a medium-speed mixer, and stir in a vacuum for 40 minutes. After stirring evenly, add 100 g of D30 solvent oil and stir for 20 minutes to obtain a silicone coating.

[0043] Example 4 A method for preparing a multifunctional organosilicon coating comprises the following steps: S1, 80 g of 80000 mPa.s α, ω-terminated hydroxyl polydimethylsiloxane, 120 g of 10000 mPa.s α, ω-terminated hydroxyl polydimethylsiloxane, 120 g of 1500 mPa.s α, ω-terminated hydroxyl polydimethylsiloxane, 200 g of α, ω-terminated hydroxyl polyphenylsiloxane, 50 g of nano-SiO2 powder, 60 g of aluminum hydroxide, 120 g of magnesium hydroxide, 60 g of active nano-calcium carbonate, and 60 parts of wollastonite were added to a low-speed vacuum mixer, and the mixture was kneaded under heating (high temperature of 130°C) and vacuum (≥0.085 MPa) for 3 h to obtain a base material, and then cooled to room temperature; S2. Add the base material cooled to room temperature and the cross-linking agent tetrabutyl ketoxime silane 10g, methyltributyketoxime silane 12.5g, vinyltributyketoxime silane 7.5g, coupling agent aminopropyltriethoxysilane 2g, vinyltriethoxysilane 2g, methyltrimethoxysilane 2g, n-octyltriethoxysilane 2g, catalyst stannous dihydroxy acid 0.8g, N,N-ditetradecylamine 15g into a medium-speed mixer, and stir in vacuum for 50min. After stirring evenly, add 120g of D30 solvent oil and stir for 20min to obtain the silicone coating.

[0044] Comparative Example 1 The long-chain amine small molecule additive was removed from the finished coating formulation in Example 1, and the other formulations and steps were the same.

[0045] S1, 90 g of 80000 mPa.s α,ω-terminated hydroxyl polydimethylsiloxane, 135 g of 10000 mPa.s α,ω-terminated hydroxyl polydimethylsiloxane, 135 g of 1500 mPa.s α,ω-terminated hydroxyl polydimethylsiloxane, 180 g of α,ω-terminated hydroxyl polyphenylsiloxane, 35 g of nano-SiO2 powder, 75 g of aluminum hydroxide, 75 g of magnesium hydroxide, 50 g of active nano-calcium carbonate, and 50 g of wollastonite were added to a low-speed vacuum mixer, and the mixture was kneaded under heating (high temperature of 140°C) and vacuum (≥0.085 MPa) for 3 h to obtain a base material, and then cooled to room temperature; S2. Add the base material cooled to room temperature and the cross-linking agent 10g of methyltributylanoxime silane, 8g of vinyltributylanoxime silane, 2g of coupling agent aminopropyltriethoxysilane, 3g of glycidyloxypropyltrimethoxysilane, 2g of vinyltrimethoxysilane, and 0.5g of catalyst dibutyltin dilaurate into a medium-speed mixer, and stir in a vacuum for 50 minutes. After stirring evenly, add 150g of D30 solvent oil and stir for 20 minutes to obtain a silicone elastic anti-corrosion coating.

[0046] Comparative Example 2 The finished coating formulation in Example 1 does not use aluminum hydroxide and magnesium hydroxide, but uses active nano-calcium carbonate to fill the mass fractions thereof. Other formulations and steps are the same.

[0047] S1, 90 g of 80,000 mPa.s α,ω-terminated hydroxyl polydimethylsiloxane, 135 g of 10,000 mPa.s α,ω-terminated hydroxyl polydimethylsiloxane, 135 g of 1500 mPa.s α,ω-terminated hydroxyl polydimethylsiloxane, 180 g of α,ω-terminated hydroxyl polyphenylsiloxane, 35 g of nano-SiO2 powder, 200 g of active nano-calcium carbonate, and 50 g of wollastonite were added to a low-speed vacuum mixer, and the mixture was kneaded under heating (high temperature of 140°C) and vacuum (≥0.085 MPa) for 3 h to obtain a base material, and then cooled to room temperature; S2. Add the base material cooled to room temperature and the cross-linking agent 10g of methyltributylanoxime silane, 8g of vinyltributylanoxime silane, 2g of coupling agent aminopropyltriethoxysilane, 3g of glycidyloxypropyltrimethoxysilane, 2g of vinyltrimethoxysilane, 0.5g of catalyst dibutyltin dilaurate, and 10g of octadecylamine into a medium-speed mixer, stir in vacuum for 50 minutes, stir evenly, add 150g of D30 solvent oil, stir for 20 minutes and mix to obtain the silicone elastic anti-corrosion coating.

[0048] Comparative Example 3 The nano-SiO2 composite powder was removed from the finished coating formulation in Example 1, and wollastonite was used as the filler mass fraction. The other formulations and steps were the same.

[0049] S1, 90 g of 80000 mPa.s α,ω-terminated hydroxyl polydimethylsiloxane, 135 g of 10000 mPa.s α,ω-terminated hydroxyl polydimethylsiloxane, 135 g of 1500 mPa.s α,ω-terminated hydroxyl polydimethylsiloxane, 180 g of α,ω-terminated hydroxyl polyphenylsiloxane, 75 g of aluminum hydroxide, 75 g of magnesium hydroxide, 50 g of active nano-calcium carbonate, and 85 g of wollastonite were added to a low-speed vacuum mixer, and the mixture was kneaded under heating (high temperature of 140°C) and vacuum (≥0.085 MPa) for 3 h to obtain a base material, and then cooled to room temperature; S2. Add the base material cooled to room temperature and the cross-linking agent 10g of methyltributylanoxime silane, 8g of vinyltributylanoxime silane, 2g of coupling agent aminopropyltriethoxysilane, 3g of glycidyloxypropyltrimethoxysilane, 2g of vinyltrimethoxysilane, 0.5g of catalyst dibutyltin dilaurate, and 10g of octadecylamine into a medium-speed mixer, stir in vacuum for 50 minutes, stir evenly, add 150g of D30 solvent oil, stir for 20 minutes and mix to obtain the silicone elastic anti-corrosion coating.

[0050] Comparative Example 4 The difference between this comparative example and Example 1 is that in this comparative example, the α,ω-terminated hydroxyl polyphenylsiloxane is removed from the finished coating formula in Example 1, and an α,ω-terminated hydroxyl polydimethylsiloxane filling mass fraction of 10000 mPa.s is used, and the other formulas and steps are the same.

[0051] S1, 90 g of 80,000 mPa.s α,ω-terminated polydimethylsiloxane, 315 g of 10,000 mPa.s α,ω-terminated polydimethylsiloxane, 135 g of 1500 mPa.s α,ω-terminated polydimethylsiloxane, 35 g of nano-SiO2 powder, 75 g of aluminum hydroxide, 75 g of magnesium hydroxide, 50 g of active nano-calcium carbonate, and 50 g of wollastonite were added to a low-speed vacuum mixer, and the mixture was kneaded under heating (high temperature of 140°C) and vacuum (≥0.085 MPa) for 3 h to obtain a base material, and then cooled to room temperature; S2. Add the base material cooled to room temperature and the cross-linking agent 10g of methyltributylanoxime silane, 8g of vinyltributylanoxime silane, 2g of coupling agent aminopropyltriethoxysilane, 3g of glycidyloxypropyltrimethoxysilane, 2g of vinyltrimethoxysilane, 0.5g of catalyst dibutyltin dilaurate, and 10g of octadecylamine into a medium-speed mixer, stir in vacuum for 50 minutes, stir evenly, add 150g of D30 solvent oil, stir for 20 minutes and mix to obtain the silicone elastic anti-corrosion coating.

[0052] Experimental example Performance Testing The performance tests of the organosilicon anti-corrosion coatings prepared in the above embodiments and comparative examples were carried out, and the test indicators and test methods are as follows: The container state, construction performance, impact resistance, bending resistance, acid resistance, alkali resistance, salt spray resistance, temperature change resistance, artificial aging resistance and adhesion test are tested in accordance with the standard JG / T 224-2007 Anti-corrosion coatings for steel structures in construction.

[0053] Tensile strength and elongation at break are tested according to GB / T 528-2009.

[0054] The viscosity test was tested according to GB / T 2794-2022 Determination of viscosity of adhesives.

[0055] The water resistance was tested according to GB / T 1733-1993 Method A.

[0056] The flame retardant performance was tested according to GB / T 2408-2021.

[0057] The coating dust resistance was tested according to the following method: After the test plate preparation and curing were completed according to JG / T 512-2017, it was placed on the open-air roof of a 3-story building for 30 days, and the test results were evaluated using 0-4 levels, with 0 level being no dust pollution, 1 level being very slight, 2 level being slight, 3 level being moderate, and 4 level being severe.

[0058] Each group was tested in triplicate, and the test results are shown in Table 1: Table 1

[0059] According to the data analysis of Examples 1-4, the multifunctional silicone coating and its preparation method provided by the present application take into account the flame retardancy, dust resistance, and acid and alkali corrosion resistance of the silicone coating. According to Comparative Example 1, based on Example 1, after removing the long-chain amine small molecule additive, the contact angle, acid resistance, and dust resistance of the coating were all decreased, indicating that the use of long-chain amine small molecule additives is beneficial to improving the liquid repellency and acid liquid corrosion resistance of the coating, and also endows the coating with dust resistance. According to Comparative Example 2, based on Example 1, using nano active calcium carbonate instead of flame retardant powder aluminum hydroxide and magnesium hydroxide, the flame retardant grade of the silicone coating decreased from FV-0 to FV-2, indicating that aluminum hydroxide and magnesium hydroxide have an important influence on the flame retardant performance of the coating. According to Comparative Example 3, based on Example 1, using wollastonite instead of nano SiO2 powder, the coating appeared discoloration after 500h of alkali immersion, which indicates that nano SiO2 can form a more compact physical protection structure to protect polydimethylsiloxane from being eroded by alkali, thereby improving the alkali corrosion resistance of the coating. According to Comparative Example 4, based on Example 1, removing the alpha, omega-hydroxyl polyphenylsiloxane and using 10000mPa.s alpha, omega-hydroxyl polydimethylsiloxane to fill the mass fraction, the coating appeared discoloration after 500h of alkali immersion, which is due to the large steric hindrance of the phenyl group, which can effectively protect the side groups of polydimethylsiloxane and improve the alkali resistance of the coating. In summary, the multifunctional silicone coating and its preparation method provided by the present application take into account the flame retardancy, dust resistance, and acid and alkali corrosion resistance of the silicone coating, and are suitable for the protection and decoration of metal substrates and building concrete structures under outdoor conditions.

[0060] The above is only an embodiment of the present invention, and the common knowledge such as the specific technical solutions and / or characteristics in the solution are not described in detail here. It should be pointed out that for those skilled in the art, without departing from the technical solution of the present invention, several variations and improvements can be made, which should also be regarded as the scope of protection of the present invention, and these will not affect the effect of the implementation of the present invention and the practicality of the patent. The scope of protection required by this application shall be based on the content of its claims, and the specific implementation methods and other records in the description can be used to interpret the content of the claims.

Claims

1. A multifunctional silicone coating, characterized in that: The raw materials include, by mass, 200-400 parts of α,ω-terminated hydroxyl polydimethylsiloxane, 150-200 parts of α,ω-terminated hydroxyl polyphenylsiloxane, 20-50 parts of nano-SiO2 powder, 100-200 parts of flame retardant powder, 80-150 parts of conventional powder, 15-30 parts of crosslinking agent, 5-10 parts of coupling agent, 0.3-0.8 parts of catalyst, 5-15 parts of amine small molecule auxiliary agent, and 100-200 parts of solvent. The α,ω-terminated hydroxyl polydimethylsiloxane is mixed with multiple viscosities.

2. A multifunctional silicone coating according to claim 1, characterized in that: The α,ω-terminated hydroxyl polydimethylsiloxane is prepared by mixing α,ω-terminated hydroxyl polydimethylsiloxanes with viscosities of 80000 mPa.s, 10000 mPa.s and 1500 mPa.s in a mass ratio of 2:3:

3.

3. A multifunctional silicone coating according to claim 2, characterized in that: The viscosity of α,ω-hydroxy-terminated polyphenylsiloxane is 10000 mPa.s.

4. The multifunctional organic silicon coating according to claim 3, characterized in that: The particle size D50 of the nano-SiO2 powder is ≤100nm, and the specific surface area is ≥200m 2 / g.

5. The multifunctional silicone coating according to claim 4, characterized in that: The flame retardant powder is at least one of aluminum hydroxide and magnesium hydroxide.

6. The multifunctional organosilicon coating according to claim 5, characterized in that: The conventional powder is at least one of active nano-calcium carbonate and wollastonite; the active nano-calcium carbonate D50 is 500nm, and the wollastonite mesh number is 2000 mesh.

7. The multifunctional silicone coating according to claim 6, characterized in that: The cross-linking agent is at least one of tetrabutyl ketone oxime silane, methyltributyketone oxime silane, vinyltributyketone oxime silane, and methyltriacetone oxime silane; the coupling agent is at least two of aminopropyl triethoxysilane, glycidyloxypropyl trimethoxysilane, methacryloxypropyl trimethoxysilane, vinyl triethoxysilane, methyl trimethoxysilane, vinyl trimethoxysilane, octyl triethoxysilane, urea propyl triethoxysilane, diethylamino methyl triethoxysilane, and n-octyl triethoxysilane.

8. The multifunctional silicone coating according to claim 7, characterized in that: The catalyst is at least one of dibutyltin dilaurate, dialkyltin dihydroxyate, dialkyldiaryloxytin, and stannous dihydroxyate; the amine small molecule auxiliary agent is at least one of diundecylamine, didodecylamine, dioctadecylamine, octadecylamine, and N,N ditetradecylamine; and the solvent is D30 solvent oil.

9. The method for preparing a multifunctional organosilicon coating according to any one of claims 1 to 8, characterized in that: The steps include: S1. After stirring α,ω-hydroxy-terminated polydimethylsiloxane, α,ω-hydroxy-terminated polyphenylsiloxane, nano-SiO2 powder, flame retardant powder, and conventional powder, kneading under heating and vacuum conditions to obtain a base material, and cooling to room temperature for use; S2. Add the base material cooled to room temperature and the cross-linking agent, coupling agent, catalyst, and amine small molecule additive into a blender, stir them evenly under vacuum, add solvent oil, and stir and mix to obtain the silicone elastic anti-corrosion coating.

10. The method for preparing a multifunctional organosilicon coating according to claim 9, characterized in that: In step S1, the heating temperature is 120-150° C., the vacuum degree is ≥0.085 MPa, and the kneading time is 3 hours; in step S2, the vacuum stirring time is 40-60 minutes.

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