Water-resistant fireproof coating for steel structure and preparation method and application thereof

Abstract

This invention discloses a water-resistant fireproof coating for steel structures, its preparation method, and its application. The fireproof coating consists of component A and component B. Component A is composed of the following raw materials: phosphate ester, dispersant, defoamer, epoxy resin, modified ammonium polyphosphate, pentaerythritol, boron phosphate, nickel hydroxide, colloidal graphite, and carbon fiber. Component B is composed of the following raw materials: dispersant, defoamer, epoxy resin curing agent, zinc borate, titanium dioxide, melamine, silica, and glass fiber. This invention addresses the problem of poor water resistance in fireproof coatings for steel structures by using a coating modification treatment on the ammonium polyphosphate in the coating, which significantly reduces the hydrolysis ability of the ammonium polyphosphate and provides excellent waterproofing. Applying the modified ammonium polyphosphate to the above-mentioned fireproof coating produces a thin-film fireproof coating for steel structures that combines fireproof and heat-insulating properties with water resistance.

Description

Technical Field

[0001] This invention relates to the fields of materials science and engineering technology, and more specifically, to a water-resistant fireproof coating for steel structures, its preparation method, and its application. Background Technology

[0002] Intumescent fire-retardant coatings for steel structures have become a primary means of fire protection due to their superior performance. While traditional halogenated flame retardants offer good fire resistance, they are gradually being phased out due to the release of toxic substances. Non-intumescent coatings require thick application, increasing structural weight and affecting aesthetics. In contrast, intumescent coatings offer high fire resistance, require less material, are lightweight, and are more aesthetically pleasing. Thin-film fire-retardant coatings for steel structures use resin-based adhesives, requiring only a 3-7mm thickness to achieve a 1-2 hour fire resistance rating, combining fire protection and decorative functions. However, issues such as low char layer strength, toxic gas release, and insufficient flame-retardant efficiency still need to be addressed.

[0003] In addition, the poor water resistance and environmental resistance of fire-retardant coatings are a major drawback of the fire-retardant coating industry. In outdoor, humid, or other harsh environments, the coating's anti-aging and corrosion resistance deteriorates. Simultaneously, components such as ammonium polyphosphate leach from the coating, and the coating loses its expansibility over time, leading to a significant decrease in the flame-retardant efficiency of the fire-retardant coating. Currently, there is no thin-film fire-retardant coating for steel structures that combines fire resistance, heat insulation, and water resistance. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned defects in the prior art and provide a water-resistant fireproof coating for steel structures, its preparation method and application. By optimizing the formula, using epoxy resin as the base adhesive, the key component of ammonium polyphosphate in the fireproof coating that is easily hydrolyzed is hydrophobically modified, so that the prepared fireproof coating has good water resistance and fireproof and heat insulation effects.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A water-resistant fireproof coating for steel structures, the fireproof coating being composed of component A and component B; wherein component A, by mass percentage, is composed of the following raw materials: 3%-10% phosphate ester, 0.5%-3% dispersant, 0.5%-4% defoamer, 30%-40% epoxy resin, 20%-30% modified ammonium polyphosphate, 12%-20% pentaerythritol, 2%-8% boron phosphate, 0.5%-2% nickel hydroxide, 3%-8% colloidal graphite, and 0.8%-2% carbon fiber; The modified ammonium polyphosphate is at least one of boron phosphate-coated ammonium polyphosphate, long-chain silane-coated ammonium polyphosphate, and stearic acid-coated ammonium polyphosphate; component B, by mass percentage, consists of the following raw materials: 0.5%-2% dispersant, 1%-3% defoamer, 35%-40% epoxy resin curing agent, 10%-20% zinc borate, 3%-7% titanium dioxide, 8%-20% melamine, 10%-20% silica, and 0.5%-3% glass fiber.

[0007] Optionally, any commercially available or known dispersant may be used in this invention, including but not limited to at least one of silicates, alkyl sulfates, and sodium alkylbenzene cyclamates.

[0008] Optionally, any commercially available or known defoamer may be used in this invention, including but not limited to at least one of mineral oil defoamers, silicone defoamers, and polymer defoamers.

[0009] Optionally, in component A, the epoxy resin is a phenolic modified epoxy resin and / or a bisphenol A epoxy resin. Preferably, the epoxy resin is a resin obtained by compounding bisphenol A epoxy resin and phenolic modified epoxy resin in a mass ratio of 4:1.

[0010] Optionally, in component A, the phosphate ester is at least one selected from triisopropylphenyl phosphate, triphenyl phosphate, toluenediphenyl phosphate, and tricresyl phosphate; preferably, triisopropylphenyl phosphate.

[0011] Optionally, in component B, the epoxy resin curing agent is at least one of polyamide curing agent, polythiol curing agent, aliphatic amine curing agent, and tertiary amine curing agent.

[0012] Optionally, the mass ratio of component A to component B is 2.5:1.

[0013] Optionally, the boron phosphate-coated modified ammonium polyphosphate includes an ammonium polyphosphate core and a boron phosphate coating layer covering the surface of the ammonium polyphosphate core; in the boron phosphate-coated modified ammonium polyphosphate, the mass percentage of the boron phosphate coating layer is 10%-15%, preferably 15%.

[0014] Optionally, the long-chain silane-coated modified ammonium polyphosphate includes an ammonium polyphosphate core and a long-chain silane coating layer covering the surface of the ammonium polyphosphate core; in the long-chain silane-coated modified ammonium polyphosphate, the mass percentage of the long-chain silane coating layer is 1%-5%, preferably 3%.

[0015] Optionally, the stearic acid-coated modified ammonium polyphosphate includes an ammonium polyphosphate core and a stearic acid coating layer covering the surface of the ammonium polyphosphate core; in the stearic acid-coated modified ammonium polyphosphate, the mass percentage of the stearic acid coating layer is 1%-8%, preferably 4%.

[0016] This invention also discloses a method for preparing the water-resistant fireproof coating for steel structures as described above, comprising the following steps: (1) Phosphate ester, dispersant and defoamer are added to epoxy resin in sequence for high-speed dispersion until uniform mixing. Then, modified ammonium polyphosphate, pentaerythritol, boron phosphate, nickel hydroxide, colloidal graphite and carbon fiber are added in sequence for high-speed dispersion in the second stage. The mixture is thoroughly mixed to obtain adhesive slurry component A. The modified ammonium polyphosphate is at least one of boron phosphate-coated ammonium polyphosphate, long-chain silane-coated ammonium polyphosphate and stearic acid-coated ammonium polyphosphate. (2) The dispersant and defoamer are added to the epoxy resin curing agent in sequence for high-speed dispersion to achieve uniform mixing. Then, zinc borate, titanium dioxide, melamine, silica and glass fiber are added in sequence for high-speed dispersion in the second stage. The mixture is fully mixed to obtain component B of the homogenate. (3) Disperse component A and component B at high speed and mix them thoroughly to obtain the water-resistant fireproof coating for steel structures.

[0017] Optionally, in step (1), the rotation speed of the first high-speed dispersion is 800 r / min, and the time of the first high-speed dispersion is 10 min; the rotation speed of the second high-speed dispersion is 2000 r / min, and the time of the second high-speed dispersion is 30 min.

[0018] Optionally, in step (2), the rotation speed of the first high-speed dispersion is 800 r / min, and the time of the first high-speed dispersion is 10 min; the rotation speed of the second high-speed dispersion is 2000 r / min, and the time of the second high-speed dispersion is 30 min.

[0019] Optionally, in step (3), the high-speed dispersion rotation speed is 2500 r / min, and the high-speed dispersion time is 20 min.

[0020] Optionally, the preparation method of the boron phosphate-coated modified ammonium polyphosphate includes the following steps: (1) Ammonium polyphosphate is dispersed in anhydrous ethanol and stirred continuously in a water bath at 60°C for 1 hour to obtain an ammonium polyphosphate suspension; wherein the mass-to-volume ratio of the ammonium polyphosphate to the anhydrous ethanol is 1 g: 10 mL; and the dispersion time is 10 min. (2) Solid boric acid is dissolved in deionized water at 80°C to obtain a boric acid aqueous solution. The boric acid aqueous solution is slowly added to the ammonium polyphosphate suspension. Phosphoric acid is then added dropwise to the resulting mixture, and the temperature is raised to 80°C and stirred continuously for 3 hours. Through the reaction of phosphoric acid and boric acid, the boron phosphate generated by the reaction is deposited and coated on the surface of the ammonium polyphosphate. The mixture is then filtered, washed, dried and pulverized to obtain boron phosphate-coated modified ammonium polyphosphate. The mass percentage of the boron phosphate coating layer in the boron phosphate-coated modified ammonium polyphosphate is 10%-15%.

[0021] Optionally, the preparation method of the long-chain silane-coated modified ammonium polyphosphate includes the following steps: drying the ammonium polyphosphate powder, then dispersing the dried ammonium polyphosphate with long-chain silane at high speed, so that the long-chain silane coats the surface of the ammonium polyphosphate, and drying to obtain the long-chain silane-coated modified ammonium polyphosphate; wherein, in the long-chain silane-coated modified ammonium polyphosphate, the mass percentage of the long-chain silane coating layer is 1%-5%.

[0022] Optionally, the high-speed dispersion process is performed at a rotation speed of 1000 r / min and for a duration of 5 min.

[0023] Optionally, the long-chain silane is at least one selected from octyltrimethoxysilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane, and octadecyltrimethoxysilane.

[0024] Optionally, the preparation method of the stearic acid-coated modified ammonium polyphosphate includes the following steps: drying the ammonium polyphosphate powder; heating solid stearic acid to melt it into a liquid state at 60°C, and then dispersing the liquid stearic acid and the dried ammonium polyphosphate at high speed to coat the surface of the ammonium polyphosphate particles with stearic acid, and then drying the mixture to obtain stearic acid-coated modified ammonium polyphosphate; wherein, the mass percentage of the stearic acid coating layer in the stearic acid-coated modified ammonium polyphosphate is 1%-8%.

[0025] Optionally, the high-speed dispersion process is performed at a rotation speed of 1000 r / min and for a duration of 5 min.

[0026] The present invention also discloses a water-resistant fireproof coating for steel structures as described above, or the application of a water-resistant fireproof coating for steel structures prepared by the preparation method described above in the protection of steel structures.

[0027] Optionally, the application includes: applying the fire-retardant coating to the surface of a steel structure and curing it to form a fire-retardant coating with a thickness of 3mm-7mm.

[0028] Implementing the embodiments of the present invention will have the following beneficial effects: (1) This invention uses epoxy resin as the matrix and studies the effects of different contents of each component on the fire resistance, char layer morphology, thermal conductivity and smoke heat release of epoxy resin-based fire retardant coating from the perspective of coating formulation ratio. A fire retardant coating with excellent fire resistance and heat insulation performance is prepared.

[0029] (2) To address the generally poor water resistance of fire-retardant coatings, the easily hydrolyzed main component, ammonium polyphosphate, was subjected to hydrophobic coating treatment, which significantly reduced the hydrolysis ability of ammonium polyphosphate and resulted in excellent waterproofing. The modified ammonium polyphosphate was applied to the above-mentioned fire-retardant coating to prepare a thin-film steel structure fire-retardant coating that combines fire resistance, heat insulation, and water resistance.

[0030] (3) The water-resistant fireproof coating for steel structures in this invention has good water resistance. The coating can resist the erosion of humid environments, is not easy to peel off or powder, can maintain its fireproof performance for a long time, extend the service life of steel structures, and reduce maintenance costs.

[0031] (4) This fireproof coating can be applied to some damp or waterproof places, such as underground buildings, offshore platforms, water conservancy projects, etc., which solves the problem that ordinary fireproof coatings are prone to failure in these environments and broadens the scope of use of steel structures in special environments. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0033] Figure 1 This is a flowchart of the preparation method of the water-resistant fireproof coating for steel structures according to Embodiment 5 of the present invention.

[0034] Figure 2 This is a digital photograph of the carbon layer morphology of a coating sample tested with a cone calorimeter in an embodiment of the present invention.

[0035] Figure 3 This is a SEM image of the carbon layer morphology of a coating sample tested with a cone calorimeter in an embodiment of the present invention. Detailed Implementation

[0036] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Example 1 The water-resistant fireproof coating for steel structures in this embodiment consists of component A and component B.

[0038] Component A, by mass percentage, consists of the following raw materials: 7% triisopropylphenyl phosphate, 1% dispersant, 1% defoamer, 35% epoxy resin (the epoxy resin is a resin obtained by compounding bisphenol A epoxy resin and phenolic modified epoxy resin in a mass ratio of 4:1, and the phenolic modified epoxy resin is Phoenix brand modified resin), 28% boron phosphate-coated modified ammonium polyphosphate, 18% pentaerythritol, 4% boron phosphate, 1% nickel hydroxide, 4% colloidal graphite, and 1% carbon fiber. The boron phosphate-coated modified ammonium polyphosphate includes an ammonium polyphosphate core and a boron phosphate coating layer covering the surface of the ammonium polyphosphate core; the boron phosphate coating layer accounts for 15% of the mass of the boron phosphate-coated modified ammonium polyphosphate.

[0039] Component B, by weight percentage, consists of the following raw materials: 1% dispersant, 1% defoamer, 40% polyamide curing agent, 20% zinc borate, 7% titanium dioxide, 20% melamine, 10% silica and 1% glass fiber.

[0040] The preparation method of boron phosphate-coated modified ammonium polyphosphate includes the following steps: (1) Disperse ammonium polyphosphate in anhydrous ethanol and stir continuously in a water bath at 60°C for 1 hour to obtain an ammonium polyphosphate suspension; wherein the mass-volume ratio of ammonium polyphosphate to anhydrous ethanol is 1 g: 10 mL; the dispersion time is 10 min.

[0041] (2) Solid boric acid was dissolved in deionized water at 80°C to obtain a boric acid aqueous solution. The boric acid aqueous solution was slowly added to the ammonium polyphosphate suspension. Phosphoric acid was then added dropwise to the resulting mixture, and the temperature was raised to 80°C and stirred continuously for 3 hours. Through the reaction of phosphoric acid and boric acid, the boron phosphate generated by the reaction was deposited and coated on the surface of the ammonium polyphosphate. The mixture was then filtered, washed, dried and pulverized to obtain the boron phosphate-coated modified ammonium polyphosphate.

[0042] The preparation method of the water-resistant fireproof coating for steel structures in this embodiment includes the following steps: (1) Triisopropylphenyl phosphate, dispersant and defoamer were added to epoxy resin in sequence and dispersed using a high-speed disperser with a speed of 800 r / min for 10 min. Then, boron phosphate-coated ammonium polyphosphate, pentaerythritol, boron phosphate, nickel hydroxide, colloidal graphite and carbon fiber were added in sequence and dispersed using a high-speed disperser with a speed of 2000 r / min for 30 min to obtain a homogenate, which was named component A.

[0043] (2) Add the dispersant and defoamer to the epoxy resin curing agent in sequence, and disperse them using a high-speed disperser with a speed of 800 r / min for 10 min. Then add zinc borate, titanium dioxide, melamine, silica and glass fiber in sequence, and disperse them using a high-speed disperser with a speed of 2000 r / min for 30 min to obtain a homogenate, which is named component B.

[0044] (3) Mix component A and component B at a mass ratio of 2.5:1 and disperse them using a high-speed disperser with a rotation speed of 2500 r / min for 20 min to obtain fireproof coating.

[0045] (4) Pour the obtained fireproof coating into a mold for curing. After drying at room temperature for 24 hours, place it in a forced-air drying oven for 10 hours to obtain a fireproof coating test sample.

[0046] The sample passed the UL-94 vertical burning test, achieving a flame retardancy rating of V-0. The fire resistance of the prepared sample was tested using the simulated large-plate method, with an alcohol torch at a temperature of 1050℃ as the heat source. The simulated large-plate method test showed that with a 4mm coating thickness, the highest back temperature of the steel plate reached 171.5℃ within 1 hour. Cone calorimetry testing was conducted using a cone calorimeter manufactured by Fire Testing Technology (UK) at 780℃ and 75kW / m³. 2 The test was conducted under a heat flux. The PHRR was 91.03 kW / m² within 1 hour using cone calorimetry. 2 The residual carbon rate was 37.65%, and digital photos of the carbon layer morphology can be found here. Figure 2 SEM photos can be found Figure 3 .

[0047] Example 2 The only difference between this embodiment and Embodiment 1 is that the modified ammonium polyphosphate is a long-chain silane-coated modified ammonium polyphosphate.

[0048] The long-chain silane-coated modified ammonium polyphosphate includes an ammonium polyphosphate core and a long-chain silane coating layer on the surface of the ammonium polyphosphate core; in the long-chain silane-coated modified ammonium polyphosphate, the long-chain silane coating layer accounts for 1.5% by mass.

[0049] The preparation method of long-chain silane-coated modified ammonium polyphosphate includes the following steps: drying ammonium polyphosphate powder, then placing the dried ammonium polyphosphate and octadecyltrimethoxysilane in a high-speed disperser, and dispersing them for 5 minutes using a high-speed disperser with a speed of 1000 r / min, so that octadecyltrimethoxysilane coats the surface of the ammonium polyphosphate, and drying the powder to obtain long-chain silane-coated modified ammonium polyphosphate; wherein, the mass percentage of the long-chain silane coating layer in the long-chain silane-coated modified ammonium polyphosphate is 1.5%.

[0050] According to the UL-94 vertical burning test, its flame retardant rating is V-0. In a simulated large-plate test, with a coating thickness of 4mm, the highest back temperature of the steel plate reached 168.2℃ within 1 hour. In a cone calorimeter test, the PHRR was 104.20 kW / m² within 1 hour. 2 The residual carbon rate was 36.95%, and digital photos of the carbon layer morphology can be found here. Figure 2 SEM photos can be found Figure 3 .

[0051] Example 3 The only difference between this embodiment and Embodiment 1 is that the modified ammonium polyphosphate is a long-chain silane-coated modified ammonium polyphosphate.

[0052] The long-chain silane-coated modified ammonium polyphosphate includes an ammonium polyphosphate core and a long-chain silane coating layer on the surface of the ammonium polyphosphate core; in the long-chain silane-coated modified ammonium polyphosphate, the long-chain silane coating layer accounts for 3% of the mass.

[0053] The preparation method of the long-chain silane-coated modified ammonium polyphosphate is the same as in Example 2.

[0054] According to the UL-94 vertical burning test, its flame retardant rating is V-0. In a simulated large-plate test, with a coating thickness of 4mm, the highest back temperature of the steel plate reached 167.4℃ within 1 hour. In a cone calorimeter test, the PHRR was 99.57 kW / m² within 1 hour. 2 The residual carbon rate was 37.75%, and digital photos of the carbon layer morphology can be found here. Figure 2 SEM photos can be found Figure 3 .

[0055] Example 4 The only difference between this embodiment and Embodiment 1 is that the modified ammonium polyphosphate is a long-chain silane-coated modified ammonium polyphosphate.

[0056] The long-chain silane-coated modified ammonium polyphosphate includes an ammonium polyphosphate core and a long-chain silane coating layer on the surface of the ammonium polyphosphate core; in the long-chain silane-coated modified ammonium polyphosphate, the long-chain silane coating layer accounts for 4.5% by mass.

[0057] The preparation method of the long-chain silane-coated modified ammonium polyphosphate is the same as in Example 2.

[0058] According to the UL-94 vertical burning test, its flame retardant rating is V-0. In a simulated large-plate test, with a coating thickness of 4mm, the highest back temperature of the steel plate reached 170.4℃ within 1 hour. In a cone calorimeter test, the PHRR was 106.74 kW / m² within 1 hour. 2 The residual carbon rate was 35.97%, and the digital photograph of the carbon layer morphology can be found here. Figure 2 SEM photos can be found Figure 3 .

[0059] Example 5 The only difference between this embodiment and Embodiment 1 is that the modified ammonium polyphosphate is stearic acid-coated modified ammonium polyphosphate.

[0060] The stearic acid-coated modified ammonium polyphosphate includes an ammonium polyphosphate core and a stearic acid coating layer on the surface of the ammonium polyphosphate core; the mass percentage of the stearic acid coating layer in the stearic acid-coated modified ammonium polyphosphate is 2%.

[0061] The preparation method of stearic acid-coated modified ammonium polyphosphate includes the following steps: drying ammonium polyphosphate powder; heating solid stearic acid to melt it into a liquid state at 60°C; then placing the liquid stearic acid and the dried ammonium polyphosphate in a high-speed disperser and dispersing them at a speed of 1000 r / min for 5 min to coat the surface of the ammonium polyphosphate particles with stearic acid; and finally drying the powder to obtain stearic acid-coated modified ammonium polyphosphate.

[0062] According to the UL-94 vertical burning test, its flame retardant rating is V-0. In a simulated large-plate test, with a coating thickness of 4mm, the highest back temperature of the steel plate reached 166.8℃ within 1 hour. In a cone calorimeter test, the PHRR was 102.27 kW / m² within 1 hour. 2 The residual carbon rate was 37.75%, and digital photos of the carbon layer morphology can be found here. Figure 2 SEM photos can be found Figure 3 .

[0063] Example 6 The only difference between this embodiment and Embodiment 1 is that the modified ammonium polyphosphate is stearic acid-coated modified ammonium polyphosphate.

[0064] The stearic acid-coated modified ammonium polyphosphate includes an ammonium polyphosphate core and a stearic acid coating layer on the surface of the ammonium polyphosphate core; in the stearic acid-coated modified ammonium polyphosphate, the mass percentage of the stearic acid coating layer is 4%.

[0065] The preparation method of stearic acid-coated modified ammonium polyphosphate is the same as in Example 5.

[0066] According to the UL-94 vertical burning test, its flame retardant rating is V-0. In a simulated large-plate test, with a coating thickness of 4mm, the highest back temperature of the steel plate reached 167.5℃ within 1 hour. In a cone calorimeter test, the PHRR was 100.85 kW / m² within 1 hour. 2 The residual carbon rate was 38.29%, and digital photos of the carbon layer morphology are available. Figure 2 SEM photos can be found Figure 3 .

[0067] Example 7 The only difference between this embodiment and Embodiment 1 is that the modified ammonium polyphosphate is stearic acid-coated modified ammonium polyphosphate.

[0068] The stearic acid-coated modified ammonium polyphosphate includes an ammonium polyphosphate core and a stearic acid coating layer on the surface of the ammonium polyphosphate core; in the stearic acid-coated modified ammonium polyphosphate, the mass percentage of the stearic acid coating layer is 6%.

[0069] The preparation method of stearic acid-coated modified ammonium polyphosphate is the same as in Example 5.

[0070] According to the UL-94 vertical burning test, its flame retardant rating is V-0. In a simulated large-plate test, with a coating thickness of 4mm, the highest back temperature of the steel plate reached 170.2℃ within 1 hour. In a cone calorimeter test, the pHRR was 98.54 kW / m² within 1 hour. 2 The residual carbon rate was 36.27%, and digital photos of the carbon layer morphology are available. Figure 2 SEM photos can be found Figure 3 .

[0071] Example 8 The only difference between this embodiment and Example 1 is that the epoxy resin is a bisphenol epoxy resin and a phenolic modified epoxy resin with a mass ratio of 3:2.

[0072] According to the UL-94 vertical burning test, its flame retardant rating is V-0. In a simulated large-plate test, with a coating thickness of 4mm, the highest back temperature of the steel plate reached 174.6℃ within 1 hour. In a cone calorimeter test, the PHRR was 117.97 kW / m² within 1 hour. 2 The residual carbon rate was 35.85%, and digital photos of the carbon layer morphology can be found here. Figure 2 SEM photos can be found Figure 3 .

[0073] Example 9 The only difference between this embodiment and Example 1 is that the epoxy resin is a bisphenol epoxy resin and a phenolic modified epoxy resin with a mass ratio of 2:3.

[0074] According to the UL-94 vertical burning test, its flame retardant rating is V-0. In a simulated large-plate test, with a coating thickness of 4mm, the highest back temperature of the steel plate reached 183.4℃ within 1 hour. In a cone calorimeter test, the pHRR was 103.73 kW / m² within 1 hour. 2 The residual carbon rate was 36.41%, and digital photos of the carbon layer morphology can be found here. Figure 2 SEM photos can be found Figure 3 .

[0075] Example 10 The only difference between this embodiment and Example 1 is that the epoxy resin is a bisphenol epoxy resin and a phenolic modified epoxy resin with a mass ratio of 1:4.

[0076] According to the UL-94 vertical burning test, its flame retardant rating is V-0. In a simulated large-plate test, with a coating thickness of 4mm, the highest back temperature of the steel plate reached 196℃ within 1 hour. In a cone calorimeter test, the PHRR was 101.02 kW / m² within 1 hour. 2 The residual carbon rate was 32.99%, and digital photos of the carbon layer morphology are available. Figure 2 SEM photos can be found Figure 3 .

[0077] Example 11 The only difference between this embodiment and Embodiment 1 is that the epoxy resin is a phenolic modified epoxy resin.

[0078] According to the UL-94 vertical burning test, its flame retardant rating is V-0. In a simulated large-plate test, with a coating thickness of 4mm, the highest back temperature of the steel plate reached 182.8℃ within 1 hour. In a cone calorimeter test, the PHRR was 114.17 kW / m² within 1 hour. 2 The residual carbon rate was 32.89%, and the digital photograph of the carbon layer morphology can be found here. Figure 2 SEM photos can be found Figure 3 .

[0079] Comparative Example 1 The only difference between this comparative example and Example 1 is that unmodified ammonium polyphosphate was used and bisphenol A epoxy resin was used.

[0080] According to the UL-94 vertical burning test, its flame retardant rating is V-0. In a simulated large-plate test, with a coating thickness of 4mm, the highest back temperature of the steel plate reached 180.4℃ within 1 hour. In a cone calorimeter test, the PHRR was 104.05 kW / m² within 1 hour. 2 The residual carbon rate was 37.29%, and digital photos of the carbon layer morphology can be found here. Figure 2 SEM photos can be found Figure 3 .

[0081] Comparative Example 2 The only difference between this comparative example and Example 1 is that unmodified ammonium polyphosphate was used.

[0082] According to the UL-94 vertical burning test, its flame retardant rating is V-0. In a simulated large-plate test, with a coating thickness of 4mm, the highest back temperature of the steel plate reached 166℃ within 1 hour. In a cone calorimeter test, the PHRR was 98.54 kW / m² within 1 hour. 2 The residual carbon rate was 38.95%, and digital photos of the carbon layer morphology can be found here. Figure 2 SEM photos can be found Figure 3 .

[0083] Application Example 1 The only difference between this application example and Example 1 is that the fire-retardant coating test sample obtained in step (4) is statically soaked in tap water for 96 hours and then dried in a blower-type drying oven for 10 hours to obtain a new fire-retardant coating test sample. All other steps are the same as in Example 1.

[0084] According to the UL-94 vertical burning test, its flame retardant rating is V-0. In a simulated large-plate test, with a coating thickness of 4mm, the highest back temperature of the steel plate reached 185.4℃ within 1 hour. In a cone calorimeter test, the pHRR was 192.81 kW / m² within 1 hour. 2 The residual carbon rate was 33.39%, and digital photos of the carbon layer morphology are available. Figure 2 SEM photos can be found Figure 3 .

[0085] Application Example 2 The only difference between this application example and Example 3 is that the fire-retardant coating test sample obtained in step (4) is statically soaked in tap water for 96 hours and then dried in a blower-type drying oven for 10 hours to obtain a new fire-retardant coating test sample. All other steps are the same as in Example 3.

[0086] According to the UL-94 vertical burning test, its flame retardant rating is V-0. In a simulated large-plate test, with a coating thickness of 4mm, the highest back temperature of the steel plate reached 173.8℃ within 1 hour. In a cone calorimeter test, the PHRR was 156.29 kW / m² within 1 hour. 2 The residual carbon rate was 34.34%, and digital photos of the carbon layer morphology can be found here. Figure 2 SEM photos can be found Figure 3 .

[0087] Application Example 3 The only difference between this application example and Example 6 is that the fire-retardant coating test sample obtained in step (4) is statically soaked in tap water for 96 hours and then dried in a blower-type drying oven for 10 hours to obtain a new fire-retardant coating test sample. All other steps are the same as in Example 6.

[0088] According to the UL-94 vertical burning test, its flame retardant rating is V-0. In a simulated large-plate test, with a coating thickness of 4mm, the highest back temperature of the steel plate reached 169.4℃ within 1 hour. In a cone calorimeter test, the PHRR was 146.71 kW / m² within 1 hour. 2 The residual carbon rate was 37.37%, and digital photos of the carbon layer morphology can be found here. Figure 2 SEM photos can be found Figure 3 .

[0089] Application Example 4 The only difference between this application example and Comparative Example 2 is that the fire-retardant coating test sample obtained in step (4) is statically soaked in tap water for 96 hours and then dried in a blower-type drying oven for 10 hours to obtain a new fire-retardant coating test sample. All other steps are the same as in Comparative Example 2.

[0090] According to the UL-94 vertical burning test, its flame retardant rating is V-1. In a simulated large-plate test, with a coating thickness of 4mm, the highest back temperature of the steel plate reached 234℃ within 1 hour. In a cone calorimeter test, the PHRR was 197.47 kW / m² within 1 hour. 2 The residual carbon rate was 32.61%, and digital photos of the carbon layer morphology are available. Figure 2 SEM photos can be found Figure 3 .

[0091] Table 1 Test

[0092] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A water-resistant fireproof coating for steel structures, characterized in that, The fire-retardant coating is composed of component A and component B; Component A, by mass percentage, consists of the following raw materials: The composition comprises 3%-10% phosphate ester, 0.5%-3% dispersant, 0.5%-4% defoamer, 30%-40% epoxy resin, 20%-30% modified ammonium polyphosphate, 12%-20% pentaerythritol, 2%-8% boron phosphate, 0.5%-2% nickel hydroxide, 3%-8% colloidal graphite, and 0.8%-2% carbon fiber; wherein the modified ammonium polyphosphate is at least one of boron phosphate-coated ammonium polyphosphate, long-chain silane-coated ammonium polyphosphate, and stearic acid-coated ammonium polyphosphate. Component B, by mass percentage, consists of the following raw materials: 0.5%-2% dispersant, 1%-3% defoamer, 35%-40% epoxy resin curing agent, 10%-20% zinc borate, 3%-7% titanium dioxide, 8%-20% melamine, 10%-20% silica and 0.5%-3% glass fiber.

2. The water-resistant fireproof coating for steel structures according to claim 1, characterized in that, In component A, the epoxy resin is a phenolic modified epoxy resin and / or a bisphenol A epoxy resin; the phosphate ester is at least one of triisopropylphenyl phosphate, triphenyl phosphate, toluene diphenyl phosphate, and tricresyl phosphate. In component B, the epoxy resin curing agent is at least one of polyamide curing agent, polythiol curing agent, aliphatic amine curing agent, and tertiary amine curing agent; The mass ratio of component A to component B is 2.5:

1.

3. The water-resistant fireproof coating for steel structures according to claim 1, characterized in that, The epoxy resin is a resin obtained by compounding bisphenol A epoxy resin and phenolic modified epoxy resin in a mass ratio of 4:

1.

4. The water-resistant fireproof coating for steel structures according to claim 1, characterized in that, The boron phosphate-coated modified ammonium polyphosphate comprises an ammonium polyphosphate core and a boron phosphate coating layer covering the surface of the ammonium polyphosphate core; in the boron phosphate-coated modified ammonium polyphosphate, the mass percentage of the boron phosphate coating layer is 10%-15%. The long-chain silane-coated modified ammonium polyphosphate comprises an ammonium polyphosphate core and a long-chain silane coating layer covering the surface of the ammonium polyphosphate core; in the long-chain silane-coated modified ammonium polyphosphate, the mass percentage of the long-chain silane coating layer is 1%-5%; The stearic acid-coated modified ammonium polyphosphate includes an ammonium polyphosphate core and a stearic acid coating layer covering the surface of the ammonium polyphosphate core; in the stearic acid-coated modified ammonium polyphosphate, the mass percentage of the stearic acid coating layer is 1%-8%.

5. A method for preparing a water-resistant fireproof coating for steel structures as described in any one of claims 1-4, characterized in that, Includes the following steps: (1) Phosphate ester, dispersant and defoamer are added to epoxy resin in sequence for high-speed dispersion in one step, and then modified ammonium polyphosphate, pentaerythritol, boron phosphate, nickel hydroxide, colloidal graphite and carbon fiber are added in sequence for high-speed dispersion in a second step to obtain component A; wherein, the modified ammonium polyphosphate is at least one of boron phosphate coated modified ammonium polyphosphate, long-chain silane coated modified ammonium polyphosphate and stearic acid coated modified ammonium polyphosphate; (2) Dispersant and defoamer are added to epoxy resin curing agent in sequence for high-speed dispersion once, and then zinc borate, titanium dioxide, melamine, silica and glass fiber are added in sequence for high-speed dispersion a second time to obtain component B; (3) Disperse component A and component B at high speed to obtain the water-resistant fireproof coating for steel structures.

6. The preparation method according to claim 5, characterized in that, In step (1), the rotation speed of the first high-speed dispersion is 800 r / min, and the time of the first high-speed dispersion is 10 min; the rotation speed of the second high-speed dispersion is 2000 r / min, and the time of the second high-speed dispersion is 30 min. In step (2), the rotation speed of the first high-speed dispersion is 800 r / min, and the time of the first high-speed dispersion is 10 min; the rotation speed of the second high-speed dispersion is 2000 r / min, and the time of the second high-speed dispersion is 30 min. In step (3), the high-speed dispersion rotation speed is 2500 r / min, and the high-speed dispersion time is 20 min.

7. The preparation method according to claim 5, characterized in that, The preparation method of the boron phosphate-coated modified ammonium polyphosphate includes the following steps: (1) Ammonium polyphosphate is dispersed in anhydrous ethanol and stirred continuously in a water bath at 60°C for 1 hour to obtain an ammonium polyphosphate suspension; wherein the mass-to-volume ratio of the ammonium polyphosphate to the anhydrous ethanol is 1 g: 10 mL; and the dispersion time is 10 min. (2) Solid boric acid is dissolved in deionized water at 80°C to obtain a boric acid aqueous solution. The boric acid aqueous solution is slowly added to the ammonium polyphosphate suspension. Phosphoric acid is then added dropwise to the resulting mixture, and the temperature is raised to 80°C and stirred continuously for 3 hours. Through the reaction of phosphoric acid and boric acid, the boron phosphate generated by the reaction is deposited and coated on the surface of the ammonium polyphosphate. The mixture is then filtered, washed, dried and pulverized to obtain boron phosphate-coated modified ammonium polyphosphate. The mass percentage of the boron phosphate coating layer in the boron phosphate-coated modified ammonium polyphosphate is 10%-15%.

8. The preparation method according to claim 5, characterized in that, The preparation method of the long-chain silane-coated modified ammonium polyphosphate includes the following steps: drying ammonium polyphosphate powder, then dispersing the dried ammonium polyphosphate with long-chain silane at high speed, so that the long-chain silane coats the surface of the ammonium polyphosphate, and drying to obtain long-chain silane-coated modified ammonium polyphosphate; wherein, in the long-chain silane-coated modified ammonium polyphosphate, the mass percentage of the long-chain silane coating layer is 1%-5%; The high-speed dispersion process involves a rotation speed of 1000 r / min and a dispersion time of 5 min. The long-chain silane is at least one of octyltrimethoxysilane, dodecyltrimethoxysilane, hexadecyltrimethoxysilane, and octadecyltrimethoxysilane.

9. The preparation method according to claim 5, characterized in that, The preparation method of the stearic acid-coated modified ammonium polyphosphate includes the following steps: drying the ammonium polyphosphate powder; heating solid stearic acid to melt it into a liquid state at 60°C, then dispersing the liquid stearic acid and the dried ammonium polyphosphate at high speed to coat the surface of the ammonium polyphosphate particles with stearic acid, and drying the mixture to obtain stearic acid-coated modified ammonium polyphosphate; wherein, the mass percentage of the stearic acid coating layer in the stearic acid-coated modified ammonium polyphosphate is 1%-8%; The high-speed dispersion process involves a rotation speed of 1000 r / min and a dispersion time of 5 min.

10. The application of a water-resistant fireproof coating for steel structures as described in any one of claims 1-4, or a water-resistant fireproof coating for steel structures prepared by the preparation method described in any one of claims 5-9, in the protection of steel structures.

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