High-carbon-layer-strength intumescent steel structure fireproof coating and preparation method thereof

Abstract

The invention provides a high-carbon-layer-strength intumescent fireproof coating for a steel structure. The high-carbon-layer-strength intumescent fireproof coating for the steel structure is prepared from the following components in parts by mass: 0.3 to 0.6 part of cellulose, 18 to 23 parts of phosphorus flame retardant, 3 to 6 parts of modified nano titanium dioxide, 3 to 5 parts of modified expandable graphite, 0.6 to 1.8 parts of modified glass fiber, 1 to 3 parts of aluminum hydroxide, 1 to 3 parts of boric acid, 20 to 25 parts of emulsion, 22 to 32 parts of additive and 29 to 43 parts of water, wherein the modified nano titanium dioxide is a silane coupling agent grafted nano titanium dioxide; the modified glass fibers are alkali-treated glass fibers; the modified expandable graphite is acid-treated expandable graphite. The intumescent fire-retardant coating for the steel structure has excellent carbon skeleton strength and carbon-steel adhesion strength, the structural integrity of the intumescent fire-retardant coating can be kept under severe conditions such as high temperature, burning and airflow jetting, and the practical application performance is improved.

Description

Technical Field

[0001] The invention relates to the technical field of coatings, and mainly relates to a high-carbon layer strength expansion type steel structure fire retardant coating and a preparation method thereof. Background Art

[0002] Steel has a high strength-to-weight ratio, excellent toughness and ductility, durability and easy processing, making it an ideal building material and an ideal material for large-span structures, high-rise buildings, bridges, stadiums and other projects. However, although the melting point of steel is very high (about 1500℃), when the temperature reaches 500-600℃, the strength of steel will quickly drop to about 50% of the initial strength; at the same time, due to the excellent thermal conductivity of steel, it will quickly absorb heat in a fire, causing the temperature to rise rapidly. If fire prevention measures are not taken, the structure may lose its bearing capacity in the early stages of the fire, bend, deform or even collapse.

[0003] In practical applications, steel structures must meet certain fire resistance limits and provide sufficient fire clearances (usually 0.5-2h), and fire retardant coatings for steel structures are one of the important means to achieve this. Fire retardant coatings are divided into intumescent fire retardant coatings and non-intumescent fire retardant coatings. Among them, intumescent fire retardant coatings can form an intumescent carbon layer (with a thermal conductivity close to that of air) at high temperatures, isolating the fire source from the air and reducing the temperature rise rate of the steel, which can significantly improve the fire resistance limit of the steel structure, thereby delaying the time of structural failure.

[0004] With the acceleration of urbanization, steel structures are widely used in high-rise buildings, industrial plants, public transportation facilities, etc. These places have strict requirements for fire safety. Fire retardant coatings are widely used as one of the effective fire prevention methods. Building safety regulations in various countries require that steel structures must reach a certain fire resistance level. Fire retardant coatings have become one of the key materials to ensure the safety of steel buildings. At the same time, fire retardant coatings have the characteristics of simple construction and low cost. Compared with traditional fire prevention measures, their economic benefits are obvious. In summary, steel structure fire retardant coatings can not only effectively improve the fire resistance of steel structures and ensure the safety of buildings, but also have wide applicability and economy driven by market demand. Therefore, the application prospects of steel structure fire retardant coatings are broad and have important social value and commercial potential.

[0005] Although steel structure fire retardant coatings have achieved significant results after long-term development, the key factor of the expansion carbon layer strength has not received enough attention for a long time. In order to achieve a carbon layer that can block heat, traditional expansion fire retardant coatings excessively pursue expansion performance or expansion ratio. However, the actual fire resistance is not only related to the thickness of the carbon layer, but its mechanical strength and structural stability also determine whether the fire retardant coating can play a continuous 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 flames, violent airflow and physical damage caused by fire, the low-strength expanded carbon layer is prone to cracking and peeling, causing the steel to be exposed to high temperatures and its fire resistance limit is greatly reduced. Therefore, the optimization of the strength of the expanded carbon layer is of great significance to improving the performance of fire-retardant coatings. The higher-strength expanded carbon layer can better resist the external physical impact and the damage of high-temperature airflow in a fire, thereby maintaining its heat insulation effect and extending the protection time of the steel structure.

[0007] In addition, in the prior art, the formula of intumescent fire retardant coatings is mostly powder materials, which are often prone to problems such as poor component dispersion, which is another influencing factor leading to its poor performance.

[0008] In summary, it is necessary to develop a new technical solution to solve the defects and shortcomings in the existing technology. Summary of the invention

[0009] The high carbon layer strength intumescent steel structure fire retardant coating of the present invention has excellent carbon skeleton strength and carbon-steel adhesion strength, which is sufficient to maintain its structural integrity under adverse conditions such as high temperature, burning, and air flow jets, thereby maximizing the actual application performance of the intumescent steel structure fire retardant coating and providing a better solution for ensuring the safety of people's lives and property.

[0010] One object of the present invention is to provide a high char layer strength intumescent steel structure fire retardant coating, wherein the high char layer strength intumescent steel structure fire retardant coating comprises the following components in parts by weight:

[0011]

[0012] in,

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

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

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

[0016] Furthermore, 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] Furthermore, 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 ammonium polyphosphate of different polymerization degrees (polymerization degree>200).

[0019] Furthermore, the emulsion is selected from one or more of phosphorus-containing flame retardant emulsion, vinyl acetate copolymer emulsion, vinyl acetate-ethylene copolymer emulsion or vinyl acetate-vinyl versatate copolymer emulsion.

[0020] Furthermore, the auxiliary agent is selected from one or more of a wetting agent, a dispersant, a defoaming agent, a film-forming agent, an antifreeze agent, a pH stabilizer, a carbonizing agent, a foaming agent, an organic amine auxiliary agent, a bactericide, a mildewproof agent, a thickener or an anti-flash rust auxiliary agent.

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

[0022] Furthermore, the dispersant is selected from one or more of polyacrylic acid ammonium salt, alkyl aryl sulfonate or maleic anhydride copolymer, preferably 0.45-0.65 parts.

[0023] Furthermore, the defoaming agent is selected from one or more of polyether-modified dimethylsiloxane, polysiloxane or ethylene glycol siloxane, preferably 0.15-0.3 parts.

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

[0025] Furthermore, the antifreeze agent is selected from one or more of propylene glycol or ethylene glycol butyl ether, preferably 0.9-1.2 parts.

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

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

[0028] Furthermore, the organic amine auxiliary agent is selected from one or more of 2-amino-2-methyl-1-propanol, diethanolamine or ammonia water, preferably 0.05-0.15 parts.

[0029] Furthermore, the mildew preventer is selected from one or more of 2-methyl-4-isothiazoline-3-one or 1,2-benzisothiazolin-3-one (BIT), preferably 0.2-0.3 parts.

[0030] Furthermore, the thickener is selected from one or more of an associative alkali swelling thickener or a polyurethane thickener, preferably 0.4-0.6 parts.

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

[0032] Another object of the present invention is to provide a method for preparing the above-mentioned high char layer strength intumescent steel structure fire retardant coating, comprising the following steps:

[0033] S1, immersing nano titanium dioxide in a liquid silane coupling agent, stirring and dispersing, and then heating for reaction to obtain modified nano titanium dioxide;

[0034] S2, soaking the glass fiber in an alkaline solution, adjusting the pH, and heating the solution to obtain a modified glass fiber;

[0035] S3, soaking the expandable graphite in an acid solution, adjusting the pH, reacting, and obtaining modified expandable graphite;

[0036] S4. Add water, dispersant, wetting agent, defoamer, cellulose and pH stabilizer into a dispersion container, stir and disperse them evenly at medium speed, then add phosphorus flame retardant, carbonizing agent, foaming agent, modified nano titanium dioxide, modified glass fiber and modified expandable graphite, stir and disperse them at high speed, then add emulsion and other additives, stir and disperse them at low speed to obtain high carbon layer strength intumescent steel structure fire retardant coating.

[0037] Furthermore, step S1 can characterize whether the modification is successful through the water dispersibility. If the water dispersibility is significantly improved compared to before the modification, the modification is successful and can be used for the preparation of the fire retardant coating in the next step.

[0038] Furthermore, step S2 can also characterize whether the modification is successful through water dispersibility. If the water dispersibility is significantly improved compared to before the modification, the modification is successful and agglomeration is further suppressed.

[0039] Furthermore, step S3 can determine whether the modification is successful by characterizing the expansion ratio and the morphology of the expanded worms after heating. If the expansion ratio is higher and the thickness of the worms is more uniform after the modification, the modification is successful.

[0040] Furthermore, in step S1, the heating temperature is 50-70°C.

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

[0042] Furthermore, in step S2, the pH range is 9-10; and the heating temperature is 50-70°C.

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

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

[0045] Introducing fiber materials, including inorganic fibers (glass fibers) and thermally grown fibers (expandable graphite raw fibers), into fire retardant coatings can effectively increase the carbon skeleton strength and stability of fire retardant coatings. The fiber material itself can enhance the structural support of the carbon layer, play the role of skeleton support, and help form a denser carbon layer structure; at the same time, because of its good tensile strength, it can improve the tensile strength of the carbon layer, resist the changes in internal stress caused by expansion during the expansion process, thereby reducing the formation of cracks in the carbon layer; and, its good heat resistance and oxidation resistance can improve the durability of the carbon layer, effectively extend the life of the carbon layer, and improve the stability of the carbon layer under long-term high temperature conditions.

[0046] Glass fiber is a commonly used reinforcing material, but its large cohesive force and aspect ratio make it difficult to disperse evenly in the coating system, thus affecting the reinforcement effect.

[0047] Expandable graphite is a functional material made from natural flake graphite through a special process. It can expand rapidly under high temperature conditions and present a "fiber" worm shape, playing a similar role as inorganic fiber braided reinforced carbon layer, with an expansion rate of dozens or even hundreds of times. Traditional expandable graphite introduces acidic intercalants into the interlayer structure of natural flake graphite. The intercalants are heated to produce gas, which causes the distance between graphite layers to increase rapidly and achieve an expansion effect. However, during the placement process, the acidic intercalants between graphite layers will deteriorate to varying degrees, which significantly affects the actual application effect.

[0048] Titanium dioxide can catalyze the cross-linking reaction of organic components in the expanded carbon layer at high temperatures to generate more carbon-carbon bonds or carbon-oxygen bonds. These cross-linking reactions can make the expanded carbon layer denser and more 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 fire resistance. At the same time, at high temperatures, titanium dioxide can promote the formation of graphitized crystallites in the expanded carbon layer. The graphitized crystallite structure has high strength and thermal stability, which helps to improve the mechanical strength and crack resistance of the carbon layer, so that the carbon layer can maintain its structural stability under high temperature conditions. However, due to its low surface activity, titanium dioxide is prone to problems such as poor compatibility with other components and poor dispersibility.

[0049] Aluminum hydroxide (Al(OH) 3 ) and boric acid (H 3 BO 3 ) will dehydrate and decompose at high temperature to form aluminum oxide (Al 2O 3 ) and boron oxide (B 2 O 3 ). These oxides can form stable chemical bonds, such as covalent bonds or ionic bonds, with the iron oxides on the steel surface, thereby greatly enhancing the chemical bonding between the steel substrate and the expanded carbon layer. At the same time, aluminum oxide and boric oxide also have good wettability and can be in close contact with the surface of the steel substrate 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, the oxides fill the microscopic pores on the surface of the steel, providing a more stable physical bond. In addition, the aluminum oxide layer produced by the decomposition of aluminum hydroxide is an efficient physical barrier that can reduce the penetration of heat and oxygen, thereby protecting the surface of the steel substrate from the effects of high-temperature oxidation. This protective effect makes the expanded carbon layer more stable. In addition, aluminum hydroxide and boric acid are excellent flame retardant materials and can themselves have a good fireproof effect.

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

[0051] (1) After the modified expandable graphite of the present invention is surface treated with acid, the performance of fire expansion is significantly improved, forming loose, porous expanded worms with a large specific surface area. In the case of fire, aluminum hydroxide and boric acid can be dispersed into the holes of these expanded worms, which plays a role in 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, etc., greatly improving the carbon-steel adhesion strength, giving the material stability and durability under high temperature and harsh environment, 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 conjunction with an organic expansion flame retardant system to synergistically enhance the flame retardant ability of the flame retardant system, achieving the effect of 1+1>2.

[0052] (2) The present invention greatly improves the strength and stability of the expanded carbon layer by adding modified nano titanium dioxide, modified expandable graphite and modified glass fiber to the high carbon layer strength expandable steel structure fire retardant coating. On the one hand, for glass fiber, the surface is etched by alkali treatment to increase its surface roughness, thereby increasing the specific surface area of ​​the fiber material and its physical bonding force with the coating matrix, and at the same time, it can also increase its dispersibility. On the other hand, for expandable graphite, after surface treatment with acid, the strength of its expanded worms is higher, the fiber diameter is uniform, and the strengthening effect on the expanded carbon layer is more significant. Since no acid intercalation agent is used, there is no problem of acid intercalation degradation, and the performance is more stable. In addition, by modifying titanium dioxide with a silane coupling agent, its water dispersibility is improved, the interface bonding force is enhanced, the compatibility between it and the organic coating matrix and the water resistance of the coating are enhanced, and its reactivity with the carbon layer at high temperature is also improved, the durability and mechanical strength of the material are improved, and the structural rigidity of the carbon layer is further improved, making it more stable under extreme conditions such as fire. The present invention can maximize the strength of the carbon skeleton by combining the 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 a fire, thereby maintaining its heat insulation effect and extending the protection time of the steel structure; at the same time, it also effectively improves the compatibility between the coating components and improves the uniformity and stability of the coating.

[0053] (3) The process of the intumescent steel structure fire retardant coating of this technical solution is simple, and only minor adjustments are made to the original formula process. Existing multi-color coating manufacturers can produce this product without major changes to the production line, ensuring the continuity of production and the benefits of achieving different levels of production on the same production line.

[0054] Instruction Manual

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

[0056] In order to more clearly illustrate the technical solution of the present invention, the following examples are listed. Unless otherwise stated, the raw materials, reactions and post-treatment methods shown in the examples are common raw materials on the market and technical methods well known to those skilled in the art.

[0057] The words "preferred", "preferably", "more preferably", etc. in the present invention refer to embodiments of the present invention that can provide certain beneficial effects in certain circumstances. However, other embodiments may also be preferred under the same circumstances or other circumstances. In addition, the description of one or more preferred embodiments does not imply that other embodiments are not applicable, nor is it intended to exclude other embodiments from the scope of the present invention.

[0058] It should be understood that, except in any operating examples, or where otherwise indicated, all numbers indicating, for example, the amounts of ingredients used in the specification and claims should be understood to be modified in all cases by the term "about". Therefore, unless indicated to the contrary, the numerical parameters set forth in the following specification and the appended claims are approximate values ​​that vary depending on the desired properties to be obtained by the present invention.

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

[0060] Cellulose: Hydroxyethyl cellulose.

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

[0062] Nano titanium dioxide, rutile in crystal form, was purchased from Shanghai Huijing Sub-Nano New Materials.

[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 Fulake.

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

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

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

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

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

[0070] Defoaming agent: polyether modified dimethylsiloxane.

[0071] Film-forming aid: alcohol ester twelve.

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

[0073] Antifreeze: Propylene glycol.

[0074] Carbon-forming agent: pentaerythritol.

[0075] Foaming agent: melamine.

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

[0077] Antifungal agent: 1,2-Benzisothiazoline-3-one.

[0078] Thickener: Associative alkali swelling thickener.

[0079] Anti-flash rust additive: sodium nitrite.

[0080] Example 1

[0081] A high carbon layer strength intumescent steel structure fire retardant coating, the high carbon layer strength intumescent steel structure fire retardant coating comprising the following components in parts by mass:

[0082]

[0083]

[0084] The preparation method of the above-mentioned high carbon layer strength intumescent steel structure fire retardant coating comprises the following steps:

[0085] S1. Soak the nano titanium dioxide in γ-aminopropyltriethoxysilane, stir and disperse at 500 rpm for 30 minutes, then react at 60°C for 12 hours, filter and dry to obtain modified nano titanium dioxide; the water dispersibility test shows that the modified nano titanium dioxide is significantly improved compared with that before modification;

[0086] S2. The glass fiber is immersed in a NaOH aqueous solution with a pH of 9, reacted at 55° C. for 48 hours, centrifuged and washed with clean water to obtain a modified glass fiber; the water dispersibility test shows that the modified glass fiber has a significant improvement compared with the modified glass fiber;

[0087] S3, immersing the expandable graphite in a sulfuric acid aqueous solution with a pH of 1, reacting for 24 hours, then centrifuging and washing with clean water to obtain modified expandable graphite; by characterizing the expansion ratio and the morphology of the expanded worms after heating, it can be seen that the modified expandable graphite has a higher expansion ratio and a more uniform worm thickness than before the modification;

[0088] S4. Add water, dispersant, wetting agent, defoamer, cellulose and pH stabilizer into a dispersion container according to the above-mentioned mass fractions, stir and disperse them evenly at 800 rpm, then add phosphorus flame retardant, carbonizing agent, foaming agent, modified nano titanium dioxide, modified glass fiber and modified expandable graphite, stir and disperse them at 1200 rpm for 30 minutes until the fineness is <40 μm, then add emulsion and other additives, stir and disperse them at 500 rpm for 10 minutes to obtain high carbon layer strength intumescent steel structure fire retardant coating.

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

[0090] Example 2

[0091] A high carbon layer strength intumescent steel structure fire retardant coating, the high carbon layer strength intumescent steel structure fire retardant coating comprising the following components in parts by mass:

[0092]

[0093]

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

[0095] Example 3

[0096] A high carbon layer strength intumescent steel structure fire retardant coating, the high carbon layer strength intumescent steel structure fire retardant coating comprising the following components in parts by mass:

[0097]

[0098]

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

[0100] Comparative Example 1

[0101] A high char layer strength intumescent steel structure fire retardant coating. The difference between this comparative example and Example 1 is that the mass fraction of the modified nano titanium dioxide is replaced by commercially available titanium dioxide, and the remaining ingredients and preparation method are the same as those in Example 1.

[0102] Comparative Example 2

[0103] A high carbon layer strength expandable steel structure fire retardant coating. The difference between this comparative example and Example 1 is that the modified expandable graphite and modified glass fiber are replaced by commercially available expandable graphite and glass fiber in equal parts by mass, and the remaining ingredients and preparation method are the same as those in Example 1.

[0104] Comparative Example 3

[0105] A high char layer strength intumescent steel structure fire retardant coating. The difference between this comparative example and Example 1 is that the mass fractions of the aluminum hydroxide and boric acid are replaced by commercially available heavy calcium powder, and the remaining ingredients and preparation method are the same as those in Example 1.

[0106] Comparative Example 4

[0107] This comparative example is the BTCB-2 intumescent steel structure fire retardant coating produced by the large manufacturer Jinyu.

[0108] Test Case

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

[0110] Test method:

[0111] Expansion ratio test: Measure the thickness of the flat carbon layer after expansion and the thickness of the dry film of the coating before expansion, and make a ratio between the two to get this parameter.

[0112] Carbon skeleton strength test: The weight method is used. The specific test process is: level the expanded carbon layer and apply a certain weight on the carbon layer until the depression depth of the expanded carbon layer is >5mm, which is the carbon skeleton strength.

[0113] Carbon-steel adhesion strength test: flatten and cut the expanded carbon layer, retaining a 5mm thickness of the carbon layer on the steel substrate, and place it vertically. Completely wrap the carbon layer with a 5mm wide steel ring and apply weights at the lower edge until the carbon layer falls off the substrate. This is the carbon-steel adhesion strength.

[0114] Water resistance test: Under standard temperature and humidity conditions, immerse the cured sample completely in water until the coating bubbles, which is the water resistance limit.

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

[0116] Table 1 Performance test results of Examples 1-3 and Comparative Examples 1-4

[0117]

[0118] It can be seen from the above test results that the fire retardant coating of the present invention has excellent performance under the synergistic effect of various materials such as modified expandable graphite, aluminum hydroxide, boric acid, modified nano titanium dioxide and modified glass fiber. The fire retardant coating prepared by the embodiment has an expansion 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>24. While comparative examples 1-3 respectively replaced modified nano titanium dioxide, modified expandable graphite and modified glass fiber, aluminum hydroxide and boric acid, comparative example 4 used commercially available fire retardant coatings, and its performance all decreased to varying degrees. This shows that the present invention has excellent carbon skeleton strength and carbon-steel adhesion strength, and is sufficient to maintain its structural integrity under harsh conditions such as high temperature, burning, and airflow jets, thereby maximizing the practical application performance of the expanded steel structure fire retardant coating, and providing a better solution to ensure the safety of people's lives and property.

[0119] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above and that the present invention can be implemented in other specific forms without departing from the spirit or essential features of the present invention. Therefore, the embodiments should be considered exemplary and non-restrictive in all respects, and the scope of the present invention is defined by the appended claims rather than the above description, and it is intended that all changes falling within the meaning and scope of the equivalent elements of the claims be included in the present invention.

[0120] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A high carbon layer strength intumescent steel structure fire retardant coating, characterized in that: The high carbon layer strength intumescent steel structure fire retardant coating comprises the following components in parts by mass: 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 modified expandable graphite is acid-treated expandable graphite.

2. The high carbon layer strength intumescent steel structure fire retardant coating 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 steel structure fire retardant coating according to claim 1, characterized in that: The phosphorus-based flame retardant is selected from one or more of ammonium polyphosphate and melamine resin-coated ammonium polyphosphate.

4. The high carbon layer strength intumescent steel structure fire retardant coating according to claim 1, characterized in that: The emulsion is selected from one or more of phosphorus-containing flame retardant emulsion, vinyl acetate copolymer emulsion, vinyl acetate-ethylene copolymer emulsion or vinyl acetate-vinyl versatate copolymer emulsion.

5. The high carbon layer strength intumescent steel structure fire retardant coating according to claim 1, characterized in that: The auxiliary agent is selected from one or more of a wetting agent, a dispersant, a defoaming agent, a film-forming agent, an antifreeze agent, a pH stabilizer, a carbonizing agent, a foaming agent, an organic amine auxiliary agent, a bactericide, a mildewproof agent, a thickener or an anti-flash rust auxiliary agent.

6. The method for preparing the high carbon layer strength intumescent steel structure fire retardant coating according to any one of claims 1 to 5, characterized in that: The steps include: S1, immersing nano titanium dioxide in a liquid silane coupling agent, stirring and dispersing, and then heating for reaction to obtain modified nano titanium dioxide; S2, soaking the glass fiber in an alkaline solution, adjusting the pH, and heating the solution to obtain a modified glass fiber; S3, soaking the expandable graphite in an acid solution, adjusting the pH, reacting, and obtaining modified expandable graphite; S4. Add water, dispersant, wetting agent, defoamer, cellulose and pH stabilizer into a dispersion container, stir and disperse them evenly, then add phosphorus flame retardant, carbonizing agent, foaming agent, modified nano titanium dioxide, modified glass fiber and modified expandable graphite, stir and disperse them, then add emulsion and other additives, stir and disperse them, and obtain high carbon layer strength intumescent steel structure fire retardant coating.

7. The method for preparing the high carbon layer strength intumescent steel structure fire retardant coating according to claim 6, characterized in that: In step S1, the heating temperature is 50-70°C.

8. The method for preparing the high carbon layer strength intumescent steel structure fire retardant coating according to claim 6, characterized in that: In step S2, the pH range is 9-10; the heating temperature is 50-70°C.

9. The method for preparing the high carbon layer strength intumescent steel structure fire retardant coating according to claim 6, characterized in that: In step S3, the acid is selected from one or more of sulfuric acid, hydrochloric acid or nitric acid.

10. The method for preparing the high carbon layer strength intumescent steel structure fire retardant coating according to claim 6, characterized in that: In step S3, the pH range is 1-2.

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