Efficient flame-retardant waterproof and fireproof coating for special humid environment and preparation method of efficient flame-retardant waterproof and fireproof coating

Abstract

The invention discloses an efficient flame-retardant waterproof and fireproof coating for a special humid environment and a preparation method, and relates to the technical field of waterproof and fireproof coatings, the waterproof and fireproof coating is prepared from a composite base material, a composite flame retardant, a nano waterproof agent, a moisture-proof auxiliary agent, a functional filler and a mixed auxiliary agent; the adhesive force and flexibility of the coating are synergistically improved through a molecular chain interpenetrating network, dual protection of a super-hydrophobic surface and a compact barrier layer is achieved in combination with a core-shell structure nano waterproof agent, a molecular-level moisture-proof barrier is constructed by adopting dual-intercalation modified bentonite, water vapor permeation can be effectively inhibited, and based on a ternary synergistic flame-retardant system, the flame-retardant performance of the coating is improved. An efficient expanded carbon layer is formed through coating modification and an eutectic structure, the fire endurance of the coating can be remarkably enhanced, in addition, the functional filler strengthens the mechanical property and the flame-retardant synergistic effect through multi-stage structural design and surface modification, the cross-linked network density is optimized in cooperation with gradient polymerization and irradiation curing processes, and the fire endurance of the coating can be remarkably improved. And finally, the bottleneck of performance degradation of the traditional coating in a humid environment is broken through.

Description

Technical Field

[0001] The present invention relates to the technical field of waterproof and fireproof coatings, and in particular to a highly flame-retardant waterproof and fireproof coating for use in special humid environments and a preparation method thereof. Background Art

[0002] Paint refers to a material that is applied to the surface of an object and can form a continuous, strong film after a certain period of time. It is a multi-component functional material that forms a continuous solid film with protection, decoration or special functions on the surface of an object through coating construction. The main purpose and function of paint include protecting the surface of an object from corrosion, rust, mildew, insect damage, ultraviolet radiation, chemical erosion, mechanical wear and other damage, extending the service life of the coated object, and waterproofing, fireproofing and insulation.

[0003] Waterproof and fireproof coatings refer to special coatings that have both the core functions of waterproofing (water resistance and impermeability) and fire prevention (flame retardant and fire resistance). This type of coating is designed with a special formula to form a protective layer on the surface of objects that is both sealing and fireproof, meeting the dual needs of waterproofing and fire safety. It is a key material for modern building safety, and through technological compounding, it achieves the characteristics of being watertight and non-flammable when exposed to fire.

[0004] Existing waterproof and fire-retardant coatings generally have problems such as water absorption and expansion, flame retardant efficiency attenuation, and interface stratification. In special humid environments, they are prone to key defects such as decreased adhesion, mutual restriction between flame retardancy and waterproof performance, and insufficient weather resistance of the coating. As a result, the coating cannot maintain stable performance in humid or harsh environments, and its application scope is limited. Therefore, the present invention proposes a waterproof and fire-retardant coating for special humid environments with high efficiency and flame retardancy and a preparation method thereof to solve the problems existing in the prior art. Summary of the Invention

[0005] In response to the above problems, the purpose of the present invention is to propose a waterproof and fire-retardant coating that is highly flame-retardant and can be used in special humid environments, and a preparation method thereof, so as to solve the key defects of existing waterproof and fire-retardant coatings in special humid environments, such as decreased adhesion, mutual restriction between flame retardancy and waterproof performance, and insufficient weather resistance of the coating.

[0006] In order to achieve the purpose of the present invention, the present invention is implemented by the following technical solution: a highly flame-retardant waterproof and fire-retardant coating for special humid environments, comprising the following raw materials in parts by weight: 40 to 60 parts of a composite base material, 15 to 25 parts of a composite flame retardant, 8 to 15 parts of a nano waterproofing agent, 5 to 10 parts of a moisture-proof additive, 10 to 20 parts of a functional filler, and 2 to 5 parts of a mixing additive;

[0007] The composite base material is a composite system of water-based epoxy resin and silicone-modified acrylic resin, and the mass ratio of the water-based epoxy resin to the silicone-modified acrylic resin is 3 to 5:1; the composite flame retardant is composed of nano-grade aluminum hydroxide, ammonium polyphosphate and zinc borate in a ratio of 2:1:0.5; the moisture-proof auxiliary agent is a composite of a silane coupling agent and modified bentonite, and the mass ratio of the silane coupling agent to the modified bentonite is 1:50.

[0008] A further improvement is that the nano waterproofing agent is a fluorosilane-modified silica nanoparticle, the surface of the fluorosilane-modified silica nanoparticle is coated with an Al2O3 transition layer by atomic layer deposition technology, and the silicone resin microspheres are coated with a core-shell structure, and the silicone resin microspheres are loaded with a nano-scale zirconium phosphate flame retardant synergist with a mass fraction of 5 to 8%.

[0009] A further improvement is that the silane coupling agent in the moisture-proof additive is a mixture of γ-aminopropyltriethoxysilane and isobutyltriethoxysilane, the mass ratio of the γ-aminopropyltriethoxysilane to the isobutyltriethoxysilane is 1:2, and vinyltrimethoxysilane is additionally added as a cross-linking accelerator, accounting for 15% of the total amount. The modified bentonite is first primary intercalated with hexadecyltrimethylammonium bromide, and then 3-aminopropyltrimethoxysilane is introduced by ultrasonic-assisted impregnation for secondary intercalation.

[0010] A further improvement is that the functional filler is composed of flaky mica powder, porous silica microspheres and fumed silica in a mass ratio of 5:3:2; the porous silica microspheres are loaded with a flame retardant synergist, and the surface of the fumed silica is grafted with silfluoroalkyl.

[0011] A further improvement is that the mixing auxiliary agent includes the following raw materials in parts by weight: 0.3 to 0.8 parts of a defoaming agent, 0.5 to 1.2 parts of a leveling agent, 0.5 to 1.5 parts of a thickener, 0.7 to 1.5 parts of a curing agent and 0.2 to 0.5 parts of a light stabilizer; the defoaming agent is selected from silicone defoaming agents, the leveling agent is selected from fluorocarbon modified polyacrylates, the thickener is selected from associative polyurethane thickeners, the curing agent is selected from modified polyamine curing agents, and the light stabilizer is selected from benzotriazole ultraviolet absorbers.

[0012] A further improvement is that the specific preparation method of the organosilicon-modified acrylic resin comprises the following steps:

[0013] S1, mixing an acrylate monomer and a double-bond-containing organosilicon monomer in a molar ratio of 4:1 to prepare a prepolymer mixture;

[0014] S2, using a gradient temperature polymerization process, free radical polymerization was carried out in three stages at 60-85°C to prepare an acrylic acid copolymer;

[0015] S3. Adding 1% by weight of an epoxy silane coupling agent to the acrylic copolymer for graft modification to obtain an organosilicon-modified acrylic resin.

[0016] The preparation method of a highly flame-retardant waterproof and fire-retardant coating for use in special humid environments comprises the following steps:

[0017] Step 1: Dispersing the composite base material and the composite flame retardant at high speed under vacuum conditions to prepare a mixture;

[0018] Step 2: adding a nanometer waterproofing agent and 50% of a functional filler to the mixture, and grinding the mixture in a planetary ball mill under argon protection to obtain a grinding material;

[0019] Step 3: Add the moisture-proof additive, the remaining 50% of the functional filler and the mixing additive to the grinding material in sequence, and disperse it under the assistance of ultrasound to obtain a semi-finished coating;

[0020] Step 4: Adjust the pH of the semi-finished coating to 8.5-9.5 and then mature it to obtain a finished waterproof and fire-retardant coating.

[0021] A further improvement is that in step 4, the aging process adopts programmed temperature control: the temperature is raised to 50°C at 0.5°C / min for the first 8 hours and maintained for 8 hours, then the temperature is lowered to 35°C at 0.3°C / min and maintained for 8 hours, and electron beam irradiation is used after aging.

[0022] The beneficial effects of the present invention are as follows: the present invention integrates a composite system of organosilicon-modified resin and epoxy resin, synergistically improves the adhesion and flexibility of the coating through the interpenetrating network of molecular chains, and combines with a core-shell structure nano waterproofing agent to achieve dual protection of super-hydrophobic surface and dense barrier layer, and adopts double-intercalation modified bentonite to construct a molecular-level moisture-proof barrier, which can effectively inhibit water vapor penetration, and based on the ternary synergistic flame retardant system, through coating modification and eutectic structure to form a high-efficiency expanded carbon layer, the fire resistance limit of the coating can be significantly enhanced. In addition, the functional filler strengthens the mechanical properties and flame retardant synergistic effect through multi-level structural design and surface modification, and optimizes the cross-linking network density in conjunction with gradient polymerization and radiation curing process, ultimately breaking through the performance attenuation bottleneck of traditional coatings in humid environments, and achieving high-efficiency flame retardant and waterproof and moisture-proof properties in special humid environments, and can maintain stable performance in humid or harsh environments. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 It is a schematic flow chart of a method for preparing a long-lasting and durable waterproof coating with a self-repairing function according to the present invention. DETAILED DESCRIPTION

[0024] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. All other embodiments obtained by ordinary technicians in this field based on the embodiments of the present invention without making any creative efforts shall fall within the scope of protection of the present invention.

[0025] Waterproof and fireproof coatings are important protective materials in the construction and industrial sectors. Primarily made from polyurethane, acrylic, or cement-based materials, these coatings form a film that blocks water penetration. They offer high ductility and weather resistance, making them suitable for humid environments like basements and bathrooms. Newer products often feature environmentally friendly features, such as low-VOC water-based formulas.

[0026] Fire-retardant coatings are categorized as either intumescent or non-intumescent. The former, such as epoxy resins, foam upon exposure to fire to form a honeycomb insulation layer, while the latter rely on ingredients like vermiculite and aluminum hydroxide for direct flame retardancy (commonly found on steel structures). Some composite coatings combine both waterproofing and fireproofing, employing a silicate / polymer matrix. Through the synergistic effect of nano-flame retardants and hydrophobic molecules, they maintain long-term protection even at temperatures of 1200°C. These coatings are widely used in tunnels, cable trays, and other locations.

[0027] It should be noted that the technical means not described in detail in the embodiments of the present invention can be implemented by conventional means, and are not the key points of the invention and will not be described in detail.

[0028] Example 1

[0029] This embodiment provides a highly flame-retardant waterproof and fire-retardant coating for use in special humid environments, comprising the following raw materials in parts by weight: 40 parts of a composite base material, 15 parts of a composite flame retardant, 8 parts of a nano-waterproofing agent, 5 parts of a moisture-proofing additive, 10 parts of a functional filler, and 2 parts of a mixing additive, wherein the composite base material is a composite system of a water-based epoxy resin and an organosilicon-modified acrylic resin, the mass ratio of the two being 3:1, and the solid content being ≥50%. The water-based epoxy resin has excellent adhesion and chemical resistance, while the organosilicon-modified acrylic resin imparts good weather resistance and flexibility to the coating. This composite system enables the coating to maintain good physical properties and adhesion even in a humid environment. The epoxy equivalent weight of the water-based epoxy resin in the composite base material is 450 g / eq, and the siloxane content of the organosilicon-modified acrylic resin is 18 wt%;

[0030] The composite flame retardant is composed of nano-aluminum hydroxide, ammonium polyphosphate, and zinc borate in a ratio of 2:1:0.5. The nano-aluminum hydroxide is coated with stearic acid (coating rate ≥85%). Ammonium polyphosphate and zinc borate are melt-blended to form a eutectic structure (melting point ≥280°C). At high temperatures, the composite flame retardant can decompose and absorb heat, releasing inert gases to form an insulating carbon layer, interrupting the combustion chain reaction and achieving a highly effective flame retardant effect.

[0031] The moisture-proof additive is a composite of a silane coupling agent and modified bentonite, with the mass ratio of the two being 1:50.

[0032] In this embodiment, the nano waterproofing agent is a fluorosilane-modified silica nanoparticle with a particle size of 20 to 50 nm and a surface contact angle of ≥150°. The surface of the fluorosilane-modified silica nanoparticle is coated with a 2 nm thick Al2O3 transition layer by atomic layer deposition (ALD) technology to form an Al2O3 / SiO2 double shell structure, and its water vapor transmission rate is reduced to ≤0.5 g / (m 2 24h), fluorosilane-modified silica nanoparticles coated silicone resin microspheres in a core-shell structure, and the silicone resin microspheres were loaded with 5% by mass of a nano-scale zirconium phosphate flame retardant synergist. This structure significantly improved the waterproof performance of the coating, preventing water penetration and adapting to special humid environments. The specific implementation method is as follows:

[0033] 1) Preparation of fluorosilane-modified silica nanoparticles

[0034] Silane coupling agent treatment: Surface modification of silica nanoparticles using a fluorosilane coupling agent to form fluorosilane-modified silica nanoparticles. This step imparts superhydrophobicity to the nanoparticles, improving their dispersibility and compatibility in organic media.

[0035] 2) Atomic layer deposition (ALD) coating of Al2O3 transition layer

[0036] Surface cleaning: Clean the surface of fluorosilane-modified silica nanoparticles to remove impurities and contaminants to ensure the smooth progress of the ALD process;

[0037] ALD equipment preparation: Place the cleaned nanoparticles in the ALD reactor and evacuate or introduce inert gas to remove air and moisture;

[0038] ALD cyclic deposition: Under vacuum or inert atmosphere, ALD cycles are used to alternately introduce Al2O3 precursors (such as trimethylaluminum) and oxidants (such as water vapor). Each cycle deposits about 0.1nm of Al2O3 film. By precisely controlling the number of cycles, the target thickness of 2nm is achieved.

[0039] Temperature control: The reaction temperature should be strictly controlled in the ALD process within the range of 150-300°C to ensure the uniformity and quality of the film;

[0040] 3) Preparation of silicone resin microspheres and flame retardant loading

[0041] Microsphere synthesis: Preparation of silicone resin microspheres as coating materials, providing good mechanical properties and thermal stability;

[0042] Flame retardant loading: A 5% by mass fraction of nano-scale zirconium phosphate flame retardant synergist is loaded inside the silicone resin microspheres. Zirconium phosphate, as a flame retardant, can release non-combustible gas during combustion, forming a heat-insulating layer and improving the flame retardant effect;

[0043] 4) Construction of core-shell structure

[0044] Coated nanoparticles: Fluorosilane-modified silica nanoparticles (coated with an Al2O3 transition layer) are used as the core and coated with silicone resin microspheres by physical or chemical methods to form a core-shell structure.

[0045] In this embodiment, the silane coupling agent in the moisture-proof additive is a mixture of γ-aminopropyltriethoxysilane and isobutyltriethoxysilane in a mass ratio of 1:2, and vinyltrimethoxysilane is additionally added as a crosslinking accelerator accounting for 15% of the total amount;

[0046] The modified bentonite is treated with two intercalation processes. The specific steps are as follows:

[0047] Hexadecyltrimethylammonium bromide was first used for primary intercalation, and then 3-aminopropyltrimethoxysilane was introduced by ultrasound-assisted impregnation for secondary intercalation. The final interlayer spacing reached 4.5 nm, and the specific surface area was increased to 380 m 2 / g;

[0048] The addition of moisture-proof additives enhances the moisture-proof ability of the coating, reduces water absorption, improves chloride ion shielding rate, and adapts to humid environments.

[0049] In this embodiment, the functional filler is composed of flaky mica powder, porous silica microspheres and fumed silica, and the mass ratio of the three is 5:3:2. The pore size distribution of the porous silica microspheres is 10 to 100 nm, the porosity is ≥80%, the porous silica microspheres are loaded with a flame retardant synergist (pentabromotoluene + antimony trioxide, loading amount 15%), the surface of the fumed silica is grafted with silfluorocarbon (contact angle ≥145°), and the diameter-to-thickness ratio of the flaky mica powder is ≥50. These fillers not only enhance the mechanical properties of the coating, but also improve the flame retardancy and water resistance.

[0050] In this embodiment, the mixed additives adopt a five-component synergistic system to jointly improve the application performance and coating quality of the coating, including:

[0051] Defoaming agent: 0.3 parts of silicone defoaming agent (polyether modified polydimethylsiloxane, with an HLB value of 8);

[0052] Leveling agent: 0.5 parts of fluorocarbon modified polyacrylate (perfluoroalkyl ethoxylate);

[0053] Thickener: 0.5 parts of associative polyurethane thickener (hydrophobically modified alkali swelling emulsion);

[0054] Curing agent: 0.7 parts of modified polyamine curing agent (Mannich base modified polyamide);

[0055] Light stabilizer: 0.2 parts of benzotriazole UV absorber;

[0056] Silicone defoamers prevent bubbles from forming in the coating, fluorocarbon-modified polyacrylates improve the smoothness of the coating, associative polyurethane thickeners adjust the viscosity of the coating, modified polyamine curing agents promote coating curing, and benzotriazole UV absorbers improve the weather resistance of the coating.

[0057] In this embodiment, the preparation method of the organosilicon-modified acrylic resin includes the following steps:

[0058] S1. Monomer composition: an acrylate monomer and a double-bond-containing silicone monomer are mixed in a molar ratio of 4:1 to prepare a prepolymer mixture;

[0059] S2. Gradient polymerization: Adopting gradient temperature polymerization process, free radical polymerization is carried out in three stages at 60-85°C to prepare acrylic copolymer. The specific gradient is as follows:

[0060] The first stage is 60℃ for 2h;

[0061] The second stage is 75℃ for 1.5h;

[0062] The third stage is 85℃ for 1h;

[0063] S3. Graft modification: adding an epoxy silane coupling agent to the acrylic copolymer for graft modification, wherein the mass ratio of the acrylic copolymer to the epoxy silane coupling agent is 100:1, the grafting rate is controlled at 8%, the epoxy silane coupling agent is selected from γ-glycidyloxypropyltrimethoxysilane, and the grafting reaction is carried out at pH = 9.0.

[0064] See also Figure 1 This embodiment also provides a method for preparing a highly flame-retardant waterproof and fire-retardant coating for use in special humid environments, comprising the following steps:

[0065] Step 1: First, disperse the composite base material and composite flame retardant at a high speed of 1200r / min for 30min under vacuum conditions (-0.095MPa) to ensure that the components are fully mixed and avoid the generation of bubbles;

[0066] Step 2: Add nano-waterproofing agent and 50% functional filler, and grind them into a particle size D50 ≤ 5 μm using a planetary ball mill under argon protection, to ensure the uniform dispersion of the nano-material and improve the waterproof and flame retardant properties of the coating;

[0067] Step 3: Then, add the moisture-proof additive, the remaining 50% of the functional filler and the mixed additive in sequence, and disperse at 800 r / min for 20 minutes under the assistance of ultrasound to obtain a semi-finished coating. The use of ultrasound helps to evenly disperse the additives and fillers, thereby improving the overall performance of the coating.

[0068] The planetary ball mill uses zirconia grinding balls, a ball-to-material ratio of 8:1, a rotation speed of 300 r / min, a grinding time of 2 h, and a system temperature controlled not to exceed 45°C;

[0069] Step 4: Adjust the pH of the semi-finished coating to 8.5 and mature it for 24 hours. After maturation, the finished waterproof and fire-retardant coating is obtained. The maturation process is carried out at 40°C and relative humidity below 30%. Program temperature control is adopted: the temperature is increased to 50°C at 0.5°C / min for the first 8 hours and maintained for 8 hours, and then cooled to 35°C at 0.3°C / min and maintained for 8 hours; after maturation, electron beam irradiation treatment is adopted with an irradiation dose of 15kGy to accelerate the formation of the curing network.

[0070] The performance test of the waterproof and fire-retardant coating prepared in this embodiment was carried out, and the results are as follows:

[0071] Moisture resistance:

[0072] Saturated humidity (40℃ / RH95%) for 30 days: volume expansion rate ≤0.8%.

[0073] Salt spray test 3000h: Adhesion retention rate ≥90%.

[0074] Flame retardant:

[0075] Fire resistance limit ≥120min (ISO 834 standard).

[0076] Peak heat release rate ≤65kW / m 2 (Cone calorimetry test).

[0077] Waterproof:

[0078] Dynamic water contact angle ≥152°, sliding angle ≤3°.

[0079] 1.5MPa water pressure for 168h: penetration depth ≤0.5mm.

[0080] Example 2

[0081] This embodiment provides a highly flame-retardant waterproof and fire-retardant coating for use in special humid environments, comprising the following raw materials in parts by weight: 60 parts of a composite base material, 25 parts of a composite flame retardant, 15 parts of a nano-waterproofing agent, 10 parts of a moisture-proofing additive, 20 parts of a functional filler, and 5 parts of a mixing additive, wherein the composite base material is a composite system of a water-based epoxy resin and an organosilicon-modified acrylic resin, the mass ratio of the two being 5:1, and the solid content being ≥50%. The water-based epoxy resin has excellent adhesion and chemical resistance, and the organosilicon-modified acrylic resin imparts good weather resistance and flexibility to the coating. This composite system enables the coating to maintain good physical properties and adhesion even in a humid environment. The epoxy equivalent weight of the water-based epoxy resin in the composite base material is 500 g / eq, and the siloxane content of the organosilicon-modified acrylic resin is 25 wt%;

[0082] The composite flame retardant is composed of nano-aluminum hydroxide, ammonium polyphosphate, and zinc borate in a ratio of 2:1:0.5. The nano-aluminum hydroxide is coated with stearic acid (coating rate ≥85%). Ammonium polyphosphate and zinc borate are melt-blended to form a eutectic structure (melting point ≥280°C). At high temperatures, the composite flame retardant can decompose and absorb heat, releasing inert gases to form an insulating carbon layer, interrupting the combustion chain reaction and achieving a highly effective flame retardant effect.

[0083] The moisture-proof additive is a composite of a silane coupling agent and modified bentonite, and the mass ratio of the two is 1:50.

[0084] In this embodiment, the nano waterproofing agent is a fluorosilane-modified silica nanoparticle with a particle size of 20 to 50 nm and a surface contact angle of ≥150°. The surface of the fluorosilane-modified silica nanoparticle is coated with a 3 nm thick Al2O3 transition layer by atomic layer deposition (ALD) technology to form an Al2O3 / SiO2 double shell structure, and its water vapor transmission rate is reduced to ≤0.5 g / (m 2 24h), fluorosilane-modified silica nanoparticles coated silicone resin microspheres in a core-shell structure. The silicone resin microspheres were loaded with 8% by mass of a nano-scale zirconium phosphate flame retardant synergist. This structure significantly improved the waterproof performance of the coating, preventing water penetration and adapting to special humid environments.

[0085] In this embodiment, the silane coupling agent in the moisture-proof additive is a mixture of γ-aminopropyltriethoxysilane and isobutyltriethoxysilane in a mass ratio of 1:2, and vinyltrimethoxysilane is additionally added as a crosslinking accelerator accounting for 15% of the total amount;

[0086] The modified bentonite is treated with two intercalation processes. The specific steps are as follows:

[0087] Hexadecyltrimethylammonium bromide was first used for primary intercalation, and then 3-aminopropyltrimethoxysilane was introduced by ultrasound-assisted impregnation for secondary intercalation. The final interlayer spacing reached 5.0 nm, and the specific surface area was increased to 420 m 2 / g;

[0088] The addition of moisture-proof additives enhances the moisture-proof ability of the coating, reduces water absorption, improves chloride ion shielding rate, and adapts to humid environments.

[0089] In this embodiment, the functional filler is composed of flaky mica powder, porous silica microspheres and fumed silica, and the mass ratio of the three is 5:3:2. The pore size distribution of the porous silica microspheres is 10 to 100 nm, the porosity is ≥80%, the porous silica microspheres are loaded with a flame retardant synergist (pentabromotoluene + antimony trioxide, loading amount 20%), the surface of the fumed silica is grafted with silfluorocarbon (contact angle ≥145°), the flaky mica powder has a diameter-to-thickness ratio of ≥50, and the surface is plasma treated to form a micro-nanoscale groove structure. These fillers not only enhance the mechanical properties of the coating, but also improve the flame retardancy and water resistance.

[0090] In this embodiment, the mixed additives adopt a five-component synergistic system to jointly improve the application performance and coating quality of the coating, including:

[0091] Defoaming agent: 0.8 parts of silicone defoaming agent (polyether modified polydimethylsiloxane, with an HLB value of 12);

[0092] Leveling agent: 1.2 parts of fluorocarbon modified polyacrylate (perfluoroalkyl ethoxylate);

[0093] Thickener: 1.5 parts of associative polyurethane thickener (hydrophobically modified alkali swellable emulsion);

[0094] Curing agent: 1.5 parts of modified polyamine curing agent (Mannich base modified polyamide);

[0095] Light stabilizer: 0.5 parts of benzotriazole ultraviolet absorber;

[0096] Silicone defoamers prevent bubbles from forming in the coating, fluorocarbon-modified polyacrylates improve the smoothness of the coating, associative polyurethane thickeners adjust the viscosity of the coating, modified polyamine curing agents promote coating curing, and benzotriazole UV absorbers improve the weather resistance of the coating.

[0097] In this embodiment, the preparation method of the organosilicon-modified acrylic resin includes the following steps:

[0098] S1. Monomer composition: an acrylate monomer and a double-bond-containing silicone monomer are mixed in a molar ratio of 4:1 to prepare a prepolymer mixture;

[0099] S2. Gradient polymerization: Adopting gradient temperature polymerization process, free radical polymerization is carried out in three stages at 60-85°C to prepare acrylic copolymer. The specific gradient is as follows:

[0100] The first stage is 60℃ for 2h;

[0101] The second stage is 75℃ for 1.5h;

[0102] The third stage is 85℃ for 1h;

[0103] S3. Graft modification: adding an epoxy silane coupling agent to the acrylic copolymer for graft modification, wherein the mass ratio of the acrylic copolymer to the epoxy silane coupling agent is 100:1, the grafting rate is controlled at 12%, the epoxy silane coupling agent is selected from γ-glycidyloxypropyltrimethoxysilane, and the grafting reaction is carried out at pH = 9.5.

[0104] See also Figure 1 This embodiment also provides a method for preparing a highly flame-retardant waterproof and fire-retardant coating for use in special humid environments, comprising the following steps:

[0105] Step 1: First, disperse the composite base material and composite flame retardant at a high speed of 1500r / min for 45min under vacuum conditions (-0.095MPa) to ensure that the components are fully mixed and avoid the generation of bubbles;

[0106] Step 2: Add nano-waterproofing agent and 50% functional filler, and grind them into a particle size D50 ≤ 5 μm using a planetary ball mill under argon protection, to ensure the uniform dispersion of the nano-material and improve the waterproof and flame retardant properties of the coating;

[0107] Step 3: Then, add the moisture-proof additive, the remaining 50% of the functional filler and the mixed additive in sequence, and disperse at 1000 r / min for 30 minutes under the assistance of ultrasound to obtain a semi-finished coating. The use of ultrasound helps to evenly disperse the additives and fillers, thereby improving the overall performance of the coating.

[0108] The planetary ball mill uses zirconia grinding balls, a ball-to-material ratio of 8:1, a rotation speed of 300 r / min, a grinding time of 3 h, and a system temperature controlled not to exceed 45°C;

[0109] Step 4: Adjust the pH value of the semi-finished coating to 9.5 and mature it for 24 hours. After maturation, the finished waterproof and fire-retardant coating is obtained. The maturation process is carried out at 50°C and relative humidity below 30%. The temperature is controlled by program: the temperature is increased to 50°C at 0.5°C / min for the first 8 hours and maintained for 8 hours, and then cooled to 35°C at 0.3°C / min and maintained for 8 hours; after maturation, electron beam irradiation is used with an irradiation dose of 20 kGy to accelerate the formation of the curing network.

[0110] The performance test of the waterproof and fire-retardant coating prepared in this embodiment was carried out, and the results are as follows:

[0111] Moisture resistance:

[0112] Saturated humidity (40℃ / RH95%) for 30 days: volume expansion rate ≤0.8%.

[0113] Salt spray test 3000h: Adhesion retention rate ≥90%.

[0114] Flame retardant:

[0115] Fire resistance limit ≥120min (ISO 834 standard).

[0116] Peak heat release rate ≤65kW / m 2 (Cone calorimetry test).

[0117] Waterproof:

[0118] Dynamic water contact angle ≥152°, sliding angle ≤3°.

[0119] 1.5MPa water pressure for 168h: penetration depth ≤0.5mm.

[0120] The present invention improves weather resistance while ensuring mechanical properties through the synergistic effect of silicone modified resin and epoxy resin. The core-shell structure nano waterproofing agent realizes the dual mechanism of super hydrophobicity and penetration barrier. The interlayer intercalation structure of the modified bentonite forms a molecular-level moisture-proof barrier. The waterproof and fire-retardant coating has excellent flame retardant properties and good water resistance through the synergistic effect of components such as the composite base material, composite flame retardant, and nano waterproofing agent. It achieves high-efficiency flame retardant and waterproof and moisture-proof properties in special humid environments and can maintain stable performance in humid or harsh environments.

[0121] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A highly flame-retardant waterproof and fire-retardant coating for use in special humid environments, characterized by: The invention comprises the following raw materials in parts by weight: 40 to 60 parts of composite base material, 15 to 25 parts of composite flame retardant, 8 to 15 parts of nano waterproofing agent, 5 to 10 parts of moisture-proof auxiliary agent, 10 to 20 parts of functional filler and 2 to 5 parts of mixing auxiliary agent; The composite base material is a composite system of water-based epoxy resin and silicone-modified acrylic resin, and the mass ratio of the water-based epoxy resin to the silicone-modified acrylic resin is 3 to 5:1; the composite flame retardant is composed of nano-grade aluminum hydroxide, ammonium polyphosphate and zinc borate in a ratio of 2:1:0.5; the moisture-proof auxiliary agent is a composite of a silane coupling agent and modified bentonite, and the mass ratio of the silane coupling agent to the modified bentonite is 1:

50.

2. The highly effective flame-retardant waterproof and fire-retardant coating for use in special humid environments according to claim 1, characterized in that: The nano waterproofing agent is fluorosilane-modified silica nanoparticles. The surface of the fluorosilane-modified silica nanoparticles is coated with an Al2O3 transition layer through atomic layer deposition technology, and the silicone resin microspheres are coated with a core-shell structure. The silicone resin microspheres are loaded with a nano-scale zirconium phosphate flame retardant synergist with a mass fraction of 5 to 8%.

3. The highly flame-retardant waterproof and fire-retardant coating for use in special humid environments according to claim 1, characterized in that: The silane coupling agent in the moisture-proof additive is a mixture of γ-aminopropyltriethoxysilane and isobutyltriethoxysilane, the mass ratio of the γ-aminopropyltriethoxysilane to the isobutyltriethoxysilane is 1:2, and vinyltrimethoxysilane accounting for 15% of the total amount is additionally added as a crosslinking accelerator. The modified bentonite is first primary intercalated with hexadecyltrimethylammonium bromide, and then 3-aminopropyltrimethoxysilane is introduced by ultrasonic-assisted impregnation for secondary intercalation.

4. The highly effective flame-retardant waterproof and fire-retardant coating for use in special humid environments according to claim 1, characterized in that: The functional filler is composed of flaky mica powder, porous silica microspheres and fumed silica in a mass ratio of 5:3:2; the porous silica microspheres are loaded with a flame retardant synergist, and the surface of the fumed silica is grafted with silfluoroalkyl.

5. The highly flame-retardant waterproof and fire-retardant coating for special humid environments according to claim 1, characterized in that: The mixing auxiliary agent includes the following raw materials in parts by weight: 0.3 to 0.8 parts of a defoaming agent, 0.5 to 1.2 parts of a leveling agent, 0.5 to 1.5 parts of a thickener, 0.7 to 1.5 parts of a curing agent, and 0.2 to 0.5 parts of a light stabilizer; the defoaming agent is selected from silicone defoaming agents, the leveling agent is selected from fluorocarbon modified polyacrylates, the thickener is selected from associative polyurethane thickeners, the curing agent is selected from modified polyamine curing agents, and the light stabilizer is selected from benzotriazole ultraviolet absorbers.

6. The highly flame-retardant waterproof and fire-retardant coating for use in special humid environments according to claim 1, characterized in that: The specific preparation method of the organosilicon-modified acrylic resin comprises the following steps: S1, mixing an acrylate monomer and a double-bond-containing organosilicon monomer in a molar ratio of 4:1 to prepare a prepolymer mixture; S2, using a gradient temperature polymerization process, free radical polymerization was carried out in three stages at 60-85°C to prepare an acrylic acid copolymer; S3. Adding 1% by weight of an epoxy silane coupling agent to the acrylic copolymer for graft modification to obtain an organosilicon-modified acrylic resin.

7. The method for preparing the highly flame-retardant waterproof and fire-retardant coating for use in special humid environments according to any one of claims 1 to 6, characterized in that: The following steps are involved: Step 1: Dispersing the composite base material and the composite flame retardant at high speed under vacuum conditions to prepare a mixture; Step 2: adding a nanometer waterproofing agent and 50% of a functional filler to the mixture, and grinding the mixture in a planetary ball mill under argon protection to obtain a grinding material; Step 3: Add the moisture-proof additive, the remaining 50% of the functional filler and the mixing additive to the grinding material in sequence, and disperse it under the assistance of ultrasound to obtain a semi-finished coating; Step 4: Adjust the pH of the semi-finished coating to 8.5-9.5 and then mature it to obtain a finished waterproof and fire-retardant coating.

8. The method for preparing a highly flame-retardant waterproof and fire-retardant coating for use in special humid environments according to claim 7, characterized in that: In the step 4, the aging process adopts programmed temperature control: the temperature is raised to 50° C. at 0.5° C. / min for the first 8 hours and maintained for 8 hours, then the temperature is lowered to 35° C. at 0.3° C. / min and maintained for 8 hours, and electron beam irradiation is performed after aging.

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