High-carbon-layer-strength intumescent fire-retardant coating for steel structure and preparation method thereof

Abstract

The application provides a high-carbon-layer-strength intumescent fireproof coating for steel structure, which comprises the following components in mass fraction: cellulose 0.3-0.6 parts, phosphorus-based flame retardant 18-23 parts, modified nano-titanium dioxide 3-6 parts, modified expandable graphite 3-5 parts, modified glass fiber 0.6-1.8 parts, aluminum hydroxide 1-3 parts, boric acid 1-3 parts, emulsion 20-25 parts, auxiliary agent 22-32 parts, and water 29-43 parts; wherein the modified nano-titanium dioxide is silane coupling agent grafted nano-titanium dioxide; the modified glass fiber is alkali treated glass fiber; and the modified expandable graphite is acid treated expandable graphite. The intumescent fireproof coating for steel structure has excellent carbon skeleton strength and carbon-steel adhesion strength, and can maintain its structural integrity and improve the practical application performance under the harsh conditions such as high temperature, burning and airflow injection.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of coating technology, and particularly relates to a high-carbon-layer-strength intumescent fireproof coating for steel structure and a preparation method thereof. BACKGROUND

[0002] Due to the high strength-weight ratio, excellent toughness and ductility, durability and easy processability of steel, the steel becomes an ideal building material and an ideal material for large-span structures, high-rise buildings, bridges, stadiums and other engineering projects. However, although the melting point of steel is very high (about 1500℃), when the temperature reaches 500-600℃, the strength of the steel will rapidly decrease to about 50% of the initial strength; at the same time, due to the very good thermal conductivity of the steel, the steel will rapidly absorb heat in a fire, resulting in rapid temperature rise. If no fireproof measures are taken, the structure may lose its load-bearing capacity at the initial stage of the fire and may bend, deform or even collapse.

[0003] In practical applications, the steel structure must meet certain fire resistance limit and sufficient fire gap (usually 0.5-2h) is required, and the steel structure fireproof coating is one of the important means to achieve this. Fireproof coatings are divided into intumescent fireproof coatings and non-intumescent fireproof coatings. Among them, the intumescent fireproof coating can form an expanded carbon layer (thermal conductivity close to air) at high temperature, isolate the heat source from the air and reduce the temperature rise rate of the steel, which can significantly improve the fire resistance of the steel structure, thereby delaying the time of structural failure.

[0004] With the acceleration of urbanization, high-rise buildings, industrial plants, public transportation facilities and other places use a large amount of steel structure, and these places have strict requirements on fire safety. Fireproof coatings, as one of the effective fireproof means, are widely used. The building safety codes of various countries require that the steel structure must meet certain fire resistance rating, and the fireproof coating becomes one of the key materials to ensure the safety of steel buildings. At the same time, the fireproof coating has the characteristics of simple construction and low cost, and its economic benefits are obvious compared with traditional fireproof measures. In summary, the steel structure fireproof coating not only can effectively improve the fire resistance of the steel structure and protect the safety of the building, but also has wide applicability and economy under the driving of market demand. Therefore, the steel structure fireproof coating has a broad application prospect and important social value and commercial potential.

[0005] Although the steel structure fireproof coating has made significant progress through long-term development, the strength of the expanded carbon layer, a key factor, has not been given enough attention for a long time. In order to achieve a carbon layer that can block heat, the traditional intumescent fireproof coating excessively pursues the expansion performance or expansion ratio, but the actual fire resistance performance is not only related to the thickness of the carbon layer, and the mechanical strength and structural stability of the carbon layer also determine whether the fireproof coating can play a sustained and effective protective role in a fire.

[0006] The problem of insufficient strength of the expanded carbon layer is particularly prominent in practical applications. In a high-temperature environment, due to the impact of the flame, the intense airflow and the physical damage caused by the fire, the expanded carbon layer with low strength is prone to cracking, peeling and other phenomena, which exposes the steel to high temperature, greatly reduces the fire resistance limit. Therefore, the optimization of the strength of the expanded carbon layer is of great significance to improve the performance of the fireproof coating. The expanded carbon layer with high strength can better resist the damage of external physical impact and high-temperature airflow in the fire, thereby maintaining its heat insulation effect and prolonging the protection time of the steel structure.

[0007] In addition, in the prior art, the formula of the expanded fireproof coating is mostly a powder material, which is prone to poor component dispersion and other problems, which is another factor affecting its poor performance.

[0008] In summary, it is necessary to develop a new technical solution to solve the defects and deficiencies in the prior art. SUMMARY

[0009] The high-carbon-layer-strength expanded fireproof coating for steel structure has excellent carbon skeleton strength and carbon-steel adhesion strength, and can maintain its structural integrity under harsh conditions such as high temperature, burning and airflow injection, thereby maximizing the practical application performance of the expanded fireproof coating for steel structure and providing a better solution to ensure the safety of people's lives and property.

[0010] An object of the present application is to provide a high-carbon-layer-strength expanded fireproof coating for steel structure, which comprises the following components by mass fraction:

[0011]

[0012] Among them,

[0013] The modified nano-titanium dioxide is silane coupling agent grafted nano-titanium dioxide;

[0014] The modified glass fiber is alkali-treated glass fiber;

[0015] The modified expandable graphite is acid-treated expandable graphite.

[0016] Further, the cellulose is selected from one or more of non-ionic ethyl hydroxyethyl cellulose, methyl hydroxyethyl cellulose, methyl hydroxypropyl cellulose or hydroxyethyl cellulose ether.

[0017] Further, the phosphorus-based flame retardant is selected from one or more of ammonium polyphosphate or melamine resin-coated ammonium polyphosphate.

[0018] Preferably, the ammonium polyphosphate is preferably ammonium polyphosphate with different degrees of polymerization (degree of polymerization > 200).

[0019] Further, the emulsion is selected from one or more of a phosphorus-containing flame-retardant emulsion, a vinyl acetate co-tertiary copolymer emulsion, a vinyl acetate-ethylene copolymer emulsion, or a vinyl acetate-tertiary vinyl carbonate copolymer emulsion.

[0020] Further, the adjuvant is selected from one or more of a wetting agent, a dispersant, an antifoaming agent, a film-forming adjuvant, an anti-freezing agent, a pH stabilizer, a char-forming agent, a blowing agent, an organic amine adjuvant, a bactericide, a mildewcide, a thickening agent, or a flash rust preventive adjuvant.

[0021] Further, the wetting agent is selected from one or more of an ionic or non-ionic wetting agent, preferably 0.4-0.6 parts.

[0022] Further, the dispersant is selected from one or more of an ammonium polyacrylate salt, an alkyl aryl sulfonate, or a maleic anhydride copolymer, preferably 0.45-0.65 parts.

[0023] Further, the antifoaming agent is selected from one or more of a polyether-modified dimethyl silicone, a polysiloxane, or a glycol silicone, preferably 0.15-0.3 parts.

[0024] Further, the film-forming adjuvant is selected from one or more of a glycol ester dodecyl, propylene glycol butyl ether, dipropylene glycol methyl ether, or benzyl alcohol, preferably 0.8-1.2 parts.

[0025] Further, the anti-freezing agent is selected from one or more of propylene glycol or glycol butyl ether, preferably 0.9-1.2 parts.

[0026] Further, the char-forming agent is selected from one or more of pentaerythritol or dipentaerythritol, preferably 4-6 parts.

[0027] Further, the blowing agent is selected from one or more of melamine, urea formaldehyde resin, chlorinated paraffin, polyamide, or urea, preferably 14-18 parts.

[0028] Further, the organic amine adjuvant is selected from one or more of 2-amino-2-methyl-1-propanol, diethanolamine, or aqueous ammonia, preferably 0.05-0.15 parts.

[0029] Further, the mildewcide is selected from one or more of 2-methyl-4-isothiazolin-3-one or 1,2-benzisothiazolin-3-one (BIT), preferably 0.2-0.3 parts.

[0030] Further, the thickening agent is selected from one or more of an associative alkali-swellable thickening agent or a polyurethane thickening agent, preferably 0.4-0.6 parts.

[0031] Further, the anti-flash rust additive is selected from one or more of sodium nitrite, strontium chromate or organic polymer complex product, preferably 0.5-2 parts.

[0032] Another object of the present application is to provide a preparation method of the high-carbon-layer-strength intumescent fireproof coating.

[0033] S1, immerse nano-titanium dioxide in liquid silane coupling agent, stir and disperse, then heat and react to obtain modified nano-titanium dioxide;

[0034] S2, immerse glass fiber in alkali solution, adjust pH, heat and react to obtain modified glass fiber;

[0035] S3, immerse expandable graphite in acid solution, adjust pH, and react to obtain modified expandable graphite;

[0036] S4, add water, dispersant, wetting agent, defoaming agent, cellulose and pH stabilizer into a dispersion container, stir and disperse uniformly at medium speed, then add phosphorus-based flame retardant, char-forming agent, foaming agent, the modified nano-titanium dioxide, the modified glass fiber and the modified expandable graphite, stir and disperse at high speed, then add emulsion and the remaining additives, stir and disperse at low speed to obtain the high-carbon-layer-strength intumescent fireproof coating for steel structure.

[0037] Further, step S1 can be characterized by water dispersibility to determine whether the modification is successful, if the water dispersibility is significantly improved compared to before modification, the modification is successful, and can be used for the preparation of the fireproof coating.

[0038] Further, step S2 can also be characterized by water dispersibility to determine whether the modification is successful, if the water dispersibility is significantly improved compared to before modification, the modification is successful, and the agglomeration is further inhibited.

[0039] Further, step S3 can be characterized by the expansion ratio after heating and the expansion worm morphology to determine whether the modification is successful, if the expansion ratio after modification is higher and the worm thickness is more uniform, the modification is successful.

[0040] Further, in step S1, the heating temperature is 50-70℃.

[0041] Further, in step S1, the silane coupling agent is selected from one or more of monofunctional silane coupling agent, bifunctional silane coupling agent or other silane coupling agent.

[0042] Further, in step S2, the pH ranges from 9 to 10; the heating temperature is 50-70℃.

[0043] Further, in step S3, the acid is selected from one or more of sulfuric acid, hydrochloric acid, or nitric acid.

[0044] Further, in step S3, the pH is in the range of 1-2.

[0045] The introduction of fiber materials, including inorganic fibers (glass fibers) and thermal fibers (expandable graphite fibers), into fireproof coatings can effectively increase the carbon skeleton strength and stability of the fireproof coatings. The fiber materials themselves can enhance the structural support of the carbon layer, acting as a skeleton support, and help form a more dense carbon layer structure. At the same time, due to their good tensile strength, they can improve the tensile strength of the carbon layer and resist internal stress changes caused by expansion during the expansion process, thereby reducing the formation of carbon layer cracks. Furthermore, their good heat resistance and oxidation resistance can improve the durability of the carbon layer, effectively prolonging the life of the carbon layer and improving the stability of the carbon layer under long-term high-temperature conditions.

[0046] Glass fibers are a commonly used reinforcing material, but their high cohesion and aspect ratio make it difficult for them to disperse uniformly in the coating system, thereby affecting the reinforcing effect.

[0047] Expandable graphite is a functional material prepared from natural flake graphite through a special process. It can rapidly expand under high-temperature conditions and exhibit a "fiber" worm-like shape, similar to the function of inorganic fiber weaving to reinforce the carbon layer, with an expansion rate of several tens or even hundreds of times. Traditional expandable graphite introduces an acidic intercalation agent into the interlayer structure of natural flake graphite. The intercalation agent generates gas upon heating, causing the graphite interlayer spacing to rapidly increase and resulting in expansion. However, during storage, the acidic interlayer of the graphite deteriorates to varying degrees, significantly affecting the actual application effect.

[0048] Titanium dioxide can catalyze the cross-linking reaction of organic components in the expanded carbon layer at high temperatures, generating more carbon-carbon bonds or carbon-oxygen bonds. These cross-linking reactions can make the expanded carbon layer more dense and stable, thereby improving the structural strength of the carbon layer. The denser the carbon layer, the more effectively it can block the penetration of heat and oxygen, thereby improving the fireproof performance. At the same time, at high temperatures, titanium dioxide can promote the formation of graphitized microcrystals in the expanded carbon layer. The graphitized microcrystal structure has high strength and thermal stability, which helps to improve the mechanical strength and crack resistance of the carbon layer, thereby enabling the carbon layer to maintain its structural stability in a high-temperature environment. However, due to its low surface activity, titanium dioxide can have poor compatibility and poor dispersibility with other components.

[0049] Aluminum hydroxide (Al(OH)3) and boric acid (H3BO3) can undergo dehydration decomposition at high temperatures, producing aluminum oxide (Al2O3) and boron oxide (B2O3), respectively. These oxides can form stable chemical bonds, such as covalent or ionic bonds, with the iron oxides on the steel surface, greatly enhancing the chemical bonding between the steel substrate and the expanded carbon layer. At the same time, aluminum oxide and boron oxide also have good wettability, which can closely contact with the steel substrate surface during heating, thereby reducing the interfacial energy and improving the interfacial compatibility. This wetting effect enhances the adhesion of the carbon layer to the substrate, especially under high temperature conditions, where the oxides fill the micro-pores on the steel surface, providing more stable physical bonding. In addition, the aluminum oxide layer produced by the decomposition of aluminum hydroxide is a highly efficient physical barrier that can reduce the penetration of heat and oxygen, thereby protecting the steel substrate surface from high-temperature oxidation. This protective effect makes the expanded carbon layer more stable. In addition, aluminum hydroxide and boric acid are also excellent flame retardants, which can provide good fire protection by themselves.

[0050] The present application has the following beneficial effects:

[0051] (1) The modified expandable graphite of the present application has significantly improved performance in expanding when exposed to fire after surface treatment with acid, forming loose and porous expanded worms with super large specific surface area. In the event of fire, aluminum hydroxide and boric acid can be dispersed into the pores of these expanded worms, enhancing the strength of the expanded carbon layer; at the same time, the fully dispersed aluminum hydroxide and boric acid greatly increase the contact area with the steel, and then interact with the steel through chemical bonding, physical bonding and other ways, greatly improving the carbon-steel adhesion strength, giving the material stability and durability in high temperature and harsh environments, avoiding the phenomenon of cracking and peeling of the expanded carbon layer, and improving the fire resistance limit. In addition, aluminum hydroxide and boric acid, as excellent inorganic flame retardants, can be used in combination with organic expanded flame retardant systems to synergistically enhance the flame retardant ability of the flame retardant system, achieving a 1+1>2 effect.

[0052] (2) The present application greatly improves the strength and stability of the expanded carbon layer by adding modified nano-titanium dioxide, modified expandable graphite and modified glass fiber and other materials in the high-carbon-layer-strength intumescent fireproof coating for steel structure. On the one hand, for the glass fiber, the surface is etched by alkali treatment to increase the surface roughness, thereby improving the specific surface area of the fiber material and the physical bonding force with the coating matrix, and at the same time, the dispersibility is also increased. On the other hand, for the expandable graphite, the strength of the expanded worm is higher after surface treatment with acid, the fiber diameter is uniform, the reinforcing effect on the expanded carbon layer is more significant, and since no acidic intercalating agent is used, there is no problem of acidic intercalation degradation, and the performance is more stable. In addition, by modifying the titanium dioxide with silane coupling agent, the water dispersibility is improved, the interfacial bonding force is enhanced, the compatibility between the organic coating matrix and the coating is improved, the water resistance is improved, and the reactivity with the carbon layer at high temperature is also improved, the durability and mechanical strength are improved, the structural rigidity of the carbon layer is further improved, and the performance is more stable under extreme conditions such as fire. The present application can maximize the strength of the carbon skeleton by the above-mentioned modified nano-titanium dioxide, modified expandable graphite and modified glass fiber, so that it can better resist the damage of external physical impact and high-temperature airflow in fire, thereby maintaining its heat insulation effect and prolonging the protection time of the steel structure. At the same time, the compatibility between the coating components is also improved, and the uniformity and stability of the coating are improved.

[0053] (3) The intumescent fireproof coating for steel structure of the present technical solution is simple in process, only a slight adjustment is made to the original formula process, and existing multi-color coating production enterprises can produce the product without greatly changing the production line, thereby ensuring the continuity of production and the benefits of producing different grades on the same production line.

[0054] DRAWINGS

[0055] Figure 1 The modification of the modified expandable graphite and the modified glass fiber is shown in the schematic diagram. DETAILED DESCRIPTION

[0056] In order to more clearly illustrate the technical solutions of the present application, the following examples are listed. The raw materials, reactions and post-treatment methods appearing in the examples are all common raw materials on the market and technical means familiar to those skilled in the art, unless otherwise stated.

[0057] The words "preferred", "preferably", "more preferred" and the like in the present application refer to the embodiments of the present application which can provide certain beneficial effects in certain cases. However, other embodiments can also be preferred in the same or other cases. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not available, nor is it intended to exclude other embodiments from the scope of the present application.

[0058] It should be understood, that, except in any operating examples, or otherwise indicated herein and throughout the specification, the amounts of ingredients, or all numbers such as amount of materials, used in expressing amounts of ingredients in the specification and claims should be understood as modified by the term "about". Accordingly, unless indicated to the contrary, the numerical parameters set forth in the following specification and attached claims are approximations that can vary depending upon the desired properties sought to be obtained by the present application.

[0059] The following raw materials were used in the examples and comparative examples of the present application:

[0060] Cellulose: hydroxyethyl cellulose.

[0061] Phosphorus flame retardant: ammonium polyphosphate-1000.

[0062] Nano-titanium dioxide, rutile type, purchased from Shanghai Huijingnan New Material.

[0063] Glass fiber, brand EMG13-125C, purchased from Tianfu Company; inorganic reinforcing material, fiber diameter less than 30 μm, fiber length 2 mm.

[0064] Expandable graphite, carbon content > 98%, purchased from Fuleike.

[0065] Aluminum hydroxide, brand JLH-WF1, purchased from Jin Hao; inorganic flame retardant, industrial pure, mesh number greater than 400 mesh.

[0066] Boric acid, brand AW20700, purchased from Borax; inorganic flame retardant, industrial pure, mesh number greater than 400 mesh.

[0067] Emulsion: vinyl acetate-ethylene copolymer emulsion, vinyl acetate copolymer emulsion.

[0068] Wetting agent: LCN070 wetting agent, non-ionic wetting agent.

[0069] Dispersant: Rohm & Haas 731A dispersant.

[0070] Defoaming agent: polyether modified dimethyl siloxane.

[0071] Film forming aid: alcohol ester twelve.

[0072] pH stabilizer: AR-95 pH regulator.

[0073] Antifreeze: propylene glycol.

[0074] Char former: pentaerythritol.

[0075] Foaming agent: melamine.

[0076] Organic amine aid: 2-amino-2-methyl-1-propanol.

[0077] Mildewcide: 1,2-benzisothiazolin-3-one.

[0078] Thickener: associative alkali-swellable thickener.

[0079] Flash rust preventive aid: sodium nitrite.

[0080] Example 1

[0081] A high-carbon-layer-strength intumescent fireproof coating for steel structure, comprising the following components in mass fraction:

[0082]

[0083]

[0084] A preparation method of the above high-carbon-layer-strength intumescent fireproof coating for steel structure, comprising the following steps:

[0085] S1, immerse nano titanium dioxide in γ-aminopropyl triethoxysilane, stir and disperse at 500 rpm for 30 min, then react at 60°C for 12 h, filter and dry to obtain modified nano titanium dioxide; it can be known from water dispersibility test that the modified nano titanium dioxide has obvious improvement compared with before modification;

[0086] S2, immerse glass fiber in NaOH aqueous solution with pH of 9, react at 55°C for 48 h, centrifuge and wash with clean water to obtain modified glass fiber; it can be known from water dispersibility test that the modified glass fiber has obvious improvement compared with before modification;

[0087] S3, immerse expandable graphite in sulfuric acid aqueous solution with pH of 1, react for 24 h, then centrifuge and wash with clean water to obtain modified expandable graphite; it can be known from the characterization of expansion ratio after heating and expansion worm morphology that the modified expandable graphite has higher expansion ratio and more uniform worm thickness compared with before modification;

[0088] S4, according to the above mass fraction, add water, dispersant, wetting agent, defoaming agent, cellulose and pH stabilizer into a dispersion container, stir and disperse uniformly at 800 rpm, then add phosphorus-based flame retardant, char-forming agent, foaming agent, modified nano titanium dioxide, modified glass fiber and modified expandable graphite, stir and disperse at 1200 rpm for 30 min to a fineness of <40 μm, then add emulsion and the remaining additives, stir and disperse at 500 rpm for 10 min to obtain the high-carbon-layer-strength intumescent fireproof coating for steel structure.

[0089] Figure 1 A modification schematic diagram of modified expandable graphite and modified glass fiber is shown.

[0090] Example 2

[0091] A high carbon layer strength intumescent fire-retardant coating for steel structure, which comprises the following components in mass fraction:

[0092]

[0093]

[0094] The preparation method of the above high carbon layer strength intumescent fire-retardant coating for steel structure is the same as that of Example 1.

[0095] Example 3

[0096] A high carbon layer strength intumescent fire-retardant coating for steel structure, which comprises the following components in mass fraction:

[0097]

[0098]

[0099] The preparation method of the above high carbon layer strength intumescent fire-retardant coating for steel structure is the same as that of Example 1.

[0100] Comparative Example 1

[0101] A high carbon layer strength intumescent fire-retardant coating for steel structure, which is different from Example 1 in that the modified nano-titanium dioxide is replaced by commercially available titanium dioxide in equal mass fraction, and the rest of the components and the preparation method are the same as those of Example 1.

[0102] Comparative Example 2

[0103] A high carbon layer strength intumescent fire-retardant coating for steel structure, which is different from Example 1 in that the modified expandable graphite and modified glass fiber are respectively replaced by commercially available expandable graphite and glass fiber in equal mass fraction, and the rest of the components and the preparation method are the same as those of Example 1.

[0104] Comparative Example 3

[0105] A high carbon layer strength intumescent fire-retardant coating for steel structure, which is different from Example 1 in that the aluminum hydroxide and boric acid are replaced by commercially available heavy calcium powder in equal mass fraction, and the rest of the components and the preparation method are the same as those of Example 1.

[0106] Comparative Example 4

[0107] This comparative example is a large factory Jinyu BTCB-2 intumescent fire-retardant coating for steel structure.

[0108] Test Example

[0109] The performance of Examples 1-3 and Comparative Examples 1-4 was tested.

[0110] Test method:

[0111] Swelling ratio test: The thickness of the flat carbon layer after swelling was measured, and the thickness of the dry coating film before swelling was measured, and the ratio of the two was obtained.

[0112] Carbon skeleton strength test: The specific test procedure was as follows: the expanded carbon layer was flattened, and a certain weight of weight was applied to the carbon layer until the depth of the expanded carbon layer was >5mm, which was the carbon skeleton strength.

[0113] Carbon-steel adhesion strength test: The expanded carbon layer was flattened and cut, and a 5mm thick carbon layer on the steel substrate was reserved and placed vertically. A 5mm wide steel ring completely wrapped the carbon layer, and a weight was applied to the lower edge until the carbon layer fell off the substrate, which was the carbon-steel adhesion strength.

[0114] Water resistance strength test: The cured sample was completely immersed in water under standard temperature and humidity conditions until the coating blistered, which was the water resistance limit.

[0115] The test results are shown in Table 1.

[0116] Table 1 Test results of performance of Examples 1-3 and Comparative Examples 1-4

[0117]

[0118] From the above test results, it can be seen that the fireproof coating of the present application has excellent performance under the synergistic action of modified expandable graphite, aluminum hydroxide, boric acid, modified nano titanium dioxide and modified glass fiber and other materials. The fireproof coating prepared in the examples has a swelling ratio of up to 47, a carbon skeleton strength of up to 260g, a carbon-steel adhesion strength of up to 385g, and a water resistance of >24. Comparative Examples 1-3 respectively replaced modified nano titanium dioxide, modified expandable graphite and modified glass fiber, aluminum hydroxide and boric acid, and Comparative Example 4 used a commercially available fireproof coating, and the performance of all of them decreased to different degrees. This shows that the present application has excellent carbon skeleton strength and carbon-steel adhesion strength, and can maintain its structural integrity under harsh conditions such as high temperature, burning and air jet, thereby maximizing the practical application performance of the intumescent steel structure fireproof coating, and providing a better solution for ensuring people's life and property safety.

[0119] It will be obvious to a person skilled in the art that the application is not limited to the details of the above-described exemplary embodiments, but that the application can be implemented in other embodiments without departing from the scope of the application. The embodiments are therefore to be seen as exemplary and in no way restrictive, the scope of the application being defined by the claims below rather than by the above description, and all variations falling within the meaning and range of equivalency of the essential characteristics of the claims are therefore intended to be embraced therein.

[0120] Furthermore, it should be understood that although the description is made according to embodiments, not every embodiment contains only one independent technical solution, and the description is made in this way only for the sake of clarity, and a person skilled in the art should consider the description as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by a person skilled in the art.

Claims

1. A high-carbon layer strength intumescent fireproof coating for steel structures, characterized in that, The high-carbon layer strength intumescent fireproof coating for steel structures comprises the following components in parts by weight: 0.3-0.6 parts cellulose 18-23 parts of phosphorus-based flame retardant 3-6 parts of modified nano titanium dioxide 3-6 parts of modified expandable graphite 0.6-1.8 parts modified glass fiber 1-3 parts aluminum hydroxide 1-3 parts boric acid 20-25 parts of emulsion 22-32 parts of auxiliary agent 29-43 parts water; in, The modified nano-titanium dioxide is nano-titanium dioxide grafted with a silane coupling agent. The modified glass fiber is an alkali-treated glass fiber; the preparation method of the alkali-treated glass fiber includes the following steps: Glass fibers are immersed in an alkaline solution, the pH is adjusted to 9-10, and the reaction is carried out by heating to obtain modified glass fibers. The modified expandable graphite is acid-treated expandable graphite; the preparation method of the acid-treated expandable graphite includes the following steps: Expandable graphite is immersed in an acid solution, the pH is adjusted to 1-2, and the reaction is carried out to obtain modified expandable graphite.

2. The high-carbon layer strength intumescent fireproof coating for steel structures according to claim 1, characterized in that, The cellulose is selected from one or more of nonionic ethyl hydroxyethyl cellulose, methyl hydroxyethyl cellulose, methyl hydroxypropyl cellulose, or hydroxyethyl cellulose ether.

3. The high-carbon layer strength intumescent fireproof coating for steel structures according to claim 1, characterized in that, The phosphorus-based flame retardant is selected from one or more of ammonium polyphosphate or melamine resin-coated ammonium polyphosphate.

4. The high-carbon layer strength intumescent fireproof coating for steel structures according to claim 1, characterized in that, The emulsion is selected from one or more of the following: phosphorus-containing flame-retardant emulsion, tertiary acetate copolymer emulsion, vinyl acetate-ethylene copolymer emulsion, or vinyl acetate-tertiary ethylene carbonate copolymer emulsion.

5. The high-carbon layer strength intumescent fireproof coating for steel structures according to claim 1, characterized in that, The additives are selected from one or more of the following: wetting agents, dispersants, defoamers, film-forming aids, antifreeze agents, pH stabilizers, charring agents, foaming agents, organic amine additives, bactericides, fungicides, thickeners, or anti-flash rust additives.

6. The high-carbon layer strength intumescent fireproof coating for steel structures according to claim 1, characterized in that, In the method for preparing alkali-treated glass fibers, the heating temperature is 50-70℃.

7. The high-carbon layer strength intumescent fireproof coating for steel structures according to claim 1, characterized in that, In the method for preparing acid-treated expandable graphite, the acid is selected from one or more of sulfuric acid, hydrochloric acid, or nitric acid.

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