Composite coating structure suitable for railway station canopy steel column protection

Abstract

The application discloses a composite coating, which comprises a primer layer and a water-based intumescent fireproof coating layer; the primer layer is formed by curing of a two-component epoxy zinc-aluminum coating, and the water-based intumescent fireproof coating layer is formed by curing of a water-based intumescent fireproof coating. The application also discloses the two-component epoxy zinc-aluminum coating and a raw material composition and a preparation method of the water-based intumescent fireproof coating. In addition, the application also discloses application of the composite coating, in particular, application in surface coating of steel columns of a railway station canopy. The composite coating can meet actual fireproof requirements of a site and long-time service requirements of the coating itself.

Description

Technical Field

[0001] This invention belongs to the field of polymer coating technology, specifically relating to a composite coating suitable for the surface protection of steel components, and especially a fireproof composite coating suitable for the steel columns of railway passenger station canopies. Background Technology

[0002] Steel components are widely used in railway passenger stations in my country due to their advantages such as good mechanical properties, high load-bearing capacity, light weight, good seismic performance, ease of factory production, short construction period, energy saving, and environmental protection. Examples include the steel columns supporting the station canopy. Since these steel columns bear weight, their coating is subject to fire-retardant requirements. The purpose is to insulate and protect the steel columns, ensuring they maintain their strength for a certain period after a fire, preventing premature melting and collapse.

[0003] The coating system for the outer surface of steel components is generally a composite structure, including a primer layer, an intermediate paint layer, and a topcoat layer. The primer primarily serves to prevent rust on the substrate and is currently mainly a two-component epoxy zinc-rich primer, such as the Chinese invention patent application CN118580744A (publication date September 3, 2024) entitled "A Waterborne Epoxy Anti-corrosion and Antistatic Primer and Its Preparation Method." This primer includes component A and component B in a weight ratio of 100:10. Component A includes waterborne epoxy resin emulsion, conductive agent, rust-inhibiting powder, talc, titanium dioxide, barium sulfate, organobentonite, fumed silica, co-solvent, dispersant, defoamer, wetting agent, adhesion promoter, thickener, and deionized water. Component B includes waterborne epoxy curing agent, anti-flash rust agent, thickener, drier, and deionized water. The intermediate paint layer can be a fire-retardant coating, providing flame retardancy, fire protection, and heat insulation. The main function of the topcoat is weather resistance, giving the coating system a longer service life. Currently, fire-retardant coatings are divided into intumescent and non-intumescent types. For example, the Chinese invention patent application CN118620419A (publication date September 10, 2024), entitled "A non-intumescent phosphogypsum fire-retardant coating for steel structures and its preparation method," discloses a fire-retardant coating formula of: 95-97 parts of duplex gypsum, 3-5 parts of inorganic lightweight insulating aggregate, 0.1-0.2 parts of retarder, 0.1 parts of glass fiber, 0.01 parts of foaming agent, and 0.2 parts of water-retaining agent. Chinese invention patent application CN118620431A (publication date September 10, 2024) discloses a water-based inorganic intumescent fire-retardant coating, its preparation method, and its application. The fire-retardant coating, by mass percentage, consists of the following raw material components: 30-50% potassium silicate solution, 4-15% styrene-acrylic emulsion, 2-8% talc, 5-15% titanium dioxide, 1-10% heavy calcium carbonate, 5-15% aluminum hydroxide, 4-10% glass powder, 1-5% modified expandable graphite, 15-30% water, and 1.7-2.7% additives. Intumescent fire-retardant coatings are gradually replacing non-intumescent fire-retardant coatings due to their advantages such as light weight and high adhesion. The aforementioned primer, intermediate coat, and topcoat, as a whole, require excellent adhesion and good compatibility between the layers. Furthermore, the fire-retardant composite coating for the steel columns of railway passenger station canopies needs to meet not only the actual on-site anti-corrosion and fire protection requirements but also the requirements for long-term service. Summary of the Invention

[0004] To address the aforementioned problems, this invention provides a composite coating suitable for the surface protection of steel components, particularly a fire-resistant composite coating for steel columns of railway passenger station canopies. This composite coating comprises a two-component epoxy zinc-aluminum primer layer and a water-based intumescent fire-retardant coating. The composite coating of this invention exhibits good compatibility between its layers, strong adhesion, and outstanding corrosion resistance and fire resistance.

[0005] Therefore, the present invention adopts the following technical solution:

[0006] A composite coating includes a primer layer and a water-based intumescent fire-retardant coating; the primer layer is cured from a two-component epoxy zinc-aluminum coating, which consists of component A and component B, which are normally stored separately and mixed when used, with a weight ratio of component A to component B of 3 to 8:1.

[0007] Component A is composed of the following components in parts by weight:

[0008] 20-45 parts of waterborne epoxy resin emulsion, 55-75 parts of zinc-aluminum alloy powder, 0.5-1.5 parts of fumed silica, 1-5 parts of silica aerogel dispersion paste, 1-2 parts of bentonite, 2-6 parts of leveling agent, 2-6 parts of dispersant, and 0.5-2 parts of defoamer.

[0009] Component B is an epoxy resin curing agent;

[0010] The water-based intumescent fire-retardant coating is cured from a water-based intumescent fire-retardant paint; the raw materials of the water-based intumescent fire-retardant paint include the following components in parts by weight:

[0011] The ingredients are: 30-55 parts silicone-acrylic resin, 6-16 parts melamine, 18-30 parts ammonium polyphosphate, 8-18 parts pentaerythritol, 0.5-4 parts refractory fiber, 4-26 parts silica aerogel dispersion, 0.5-4 parts fumed alumina, 1-4 parts thickener, 1-4 parts dispersant, 1-4 parts film-forming aid, 0.5-3 parts defoamer, 2-10 parts titanium dioxide, and 0.5-4 parts silane coupling agent.

[0012] Preferably, the dry film thickness of the primer layer is 80-100 μm; the dry film thickness of the water-based intumescent fire retardant coating is 1-5 mm.

[0013] Preferably, the weight ratio of component A to component B in the two-component epoxy zinc-aluminum coating is 4 to 6:1.

[0014] In a preferred embodiment, component A of the two-component epoxy zinc-aluminum coating consists of the following components in parts by weight:

[0015] 30-35 parts of waterborne epoxy resin emulsion, 60-70 parts of zinc-aluminum alloy powder, 0.5-1.0 parts of fumed silica, 2-4 parts of silica aerogel dispersion paste, 1-1.5 parts of bentonite, 2-4 parts of leveling agent, 2-4 parts of dispersant, and 0.5-1 part of defoamer.

[0016] For component A in the two-component epoxy zinc-aluminum coating:

[0017] Preferably, based on the total mass of the zinc-aluminum alloy powder, the percentage content of zinc is 78-88%, and the balance is aluminum.

[0018] Preferably, the zinc-aluminum alloy powder has a particle size of 300 mesh.

[0019] Preferably, the aqueous epoxy resin emulsion is selected from the brand name Epikote. TM 3520-WY-55A, Epikote TM One of the waterborne epoxy resin emulsions 3522-W-60A and DER-WB3002.

[0020] Among them, the brand name Epikote TM 3520-WY-55A and Epikote TM The manufacturer of the waterborne epoxy resin emulsion 3522-W-60A is Hexion Corporation, Inc., USA; the manufacturer of the waterborne epoxy resin emulsion with the grade DER-WB3002 is Dow Chemical Company, Inc., USA, or Olin Corporation, Inc., USA.

[0021] More preferably, the aqueous epoxy resin emulsion is selected from the brand name Epikote. TM 3520-WY-55A and Epikote TM One of the waterborne epoxy resin emulsions of 3522-W-60A.

[0022] Preferably, the fumed silica is selected from... and One of them.

[0023] Fumed silica is also known as fumed white carbon black. and The manufacturer is Evonik Degussa, a German company.

[0024] Preferably, the silica aerogel dispersion contains 20% or 30% silica aerogel.

[0025] Preferably, the dispersant is selected from... and One of them.

[0026] Preferably, the leveling agent is

[0027] Preferably, the defoamer is selected from BYK@-024 and Daejeon Chemical D-80.

[0028] The present invention also provides a method for preparing component A, comprising the following operations:

[0029] Prepare each raw material component according to the formula; add the water-based epoxy resin emulsion, dispersant and defoamer to a container equipped with a stirring device and stir for 10-20 minutes; add bentonite, silica aerogel dispersion paste and fumed silica, maintain the speed and stir for 20-40 minutes; finally add zinc aluminum alloy powder and leveling agent, stir evenly to obtain component A.

[0030] Preferably, the stirring speed is 400-600 rpm.

[0031] Preferably, component B in the two-component epoxy zinc-aluminum coating is a polyamine curing agent, more preferably a polyaliphatic amine curing agent, and particularly preferably diethylenetriamine or triethylenetetramine.

[0032] As a preferred embodiment, the water-based intumescent fire-retardant coating of the present invention comprises the following components in parts by weight:

[0033] The ingredients are: 35-45 parts silicone-acrylic resin, 8-12 parts melamine, 20-28 parts ammonium polyphosphate, 8-14 parts pentaerythritol, 0.5-2 parts refractory fiber, 8-18 parts silica aerogel dispersion, 0.5-2 parts fumed alumina, 1-2 parts thickener, 1-2 parts dispersant, 1-2 parts film-forming aid, 0.5-2 parts defoamer, 2-8 parts titanium dioxide, and 0.5-1.5 parts silane coupling agent.

[0034] As a more preferred embodiment, the water-based intumescent fire-retardant coating of the present invention comprises the following components in parts by weight:

[0035] The ingredients are: 38-42 parts silicone-acrylic resin, 8-12 parts melamine, 20-28 parts ammonium polyphosphate, 10-14 parts pentaerythritol, 1-2 parts refractory fiber, 8-18 parts silica aerogel dispersion, 1-2 parts fumed alumina, 1-2 parts thickener, 1-2 parts dispersant, 1-2 parts film-forming aid, 0.5-2 parts defoamer, 4-6 parts titanium dioxide, and 1-1.5 parts silane coupling agent.

[0036] The raw materials of the water-based intumescent fire-retardant coating include:

[0037] The silicone-acrylic resin can be selected from commercially available silicone-acrylic resin 8912 produced by Qingdao Gudao Technology Co., Ltd. or silicone-acrylic resin RS-3799A produced by Badifu.

[0038] Preferably, the refractory fiber is aluminum silicate fiber with a length of <1cm and a refractory temperature of >800℃.

[0039] Preferably, the particle size of the fumed alumina is 100–300 nm.

[0040] Preferably, the thickener is selected from RHEOBYK-425 or RHEOBYK-7610.

[0041] Preferably, the dispersant is selected from aqueous wetting and dispersing agents. or

[0042] Preferably, the film-forming aid is dodecyl alcohol ester.

[0043] Preferably, the titanium dioxide is rutile titanium dioxide with a particle size of 45-80 μm.

[0044] Preferably, in the raw materials of the water-based intumescent fire-retardant coating, the defoamer is...

[0045] The present invention also provides a method for preparing the water-based intumescent fire-retardant coating, comprising the following steps:

[0046] Prepare the raw materials according to the formula; add the silicone acrylic resin, melamine, ammonium polyphosphate, pentaerythritol, refractory fiber, silica aerogel dispersion paste, dispersant, defoamer and titanium dioxide to the equipment equipped with a stirring device in sequence, and stir for 60 to 100 minutes; then add fumed alumina, thickener, surface additive and silane coupling agent, and continue stirring for 60 to 100 minutes to obtain the final product.

[0047] Preferably, the stirring speed is 400-600 rpm.

[0048] Preferably, the composite coating further includes a topcoat layer, and the water-based intumescent fire-retardant coating is located between the topcoat layer and the primer layer.

[0049] Preferably, the topcoat layer is formed by curing fluorocarbon resin coatings or polyurethane coatings.

[0050] Furthermore, the present invention also provides the application of the composite coating in the coating of steel components.

[0051] In particular, the present invention provides the application of the composite coating in the coating of steel columns for railway passenger station canopies.

[0052] Therefore, another objective of this invention is to provide a construction process for coating the surface of steel components, comprising using the two-component epoxy zinc-aluminum coating described in this invention as a primer and using the water-based intumescent fire-retardant coating as a fire-retardant coating, comprising the following steps:

[0053] S1. Clean and remove rust from the surface of steel components that need to be painted, so that the surface reaches Sa2.5 level or above;

[0054] S2. Mix component A and component B evenly according to the weight ratio, spray or brush onto the surface with Sa2.5 grade or above, let it dry naturally, and repeat spraying or brushing until the dry film thickness reaches 80-100μm;

[0055] S3. Spray or brush the water-based intumescent fire retardant coating onto the primer layer obtained in step S2, and allow it to dry naturally; repeat the spraying or brushing until the dry film thickness reaches 1-5 mm.

[0056] Preferably, the construction process further includes the following after step S3:

[0057] S4. Spray or brush the fluorocarbon resin coating or polyurethane coating onto the fireproof coating obtained in step S3, and let it dry naturally; repeat the spraying or brushing until the dry film thickness reaches 3-5 mm.

[0058] The composite coating provided by this invention, which includes a primer layer and a water-based intumescent fireproof coating, is particularly suitable for coating steel columns of railway passenger station canopies. It can meet both the actual fire protection requirements on site and the long-term service requirements of the coating itself. Detailed Implementation

[0059] The present invention will be described below with reference to specific embodiments. Those skilled in the art will understand that these embodiments are for illustrative purposes only and do not limit the scope of the invention in any way.

[0060] Unless otherwise specified, the experimental methods used in the following examples are conventional methods. Unless otherwise specified, all raw materials and reagents used in the following examples are commercially available products. The manufacturers and product information of some raw materials and reagents are as follows:

[0061] Waterborne epoxy resin emulsion: Hexion (USA), Epikote TM 3520-WY-55A;

[0062] Zinc-aluminum alloy powder: Dinghong (Shanghai) New Material Technology Co., Ltd., ZnAl12, 300 mesh;

[0063] Fumed silica: Evonik Degussa, Germany, A200;

[0064] Silica aerogel dispersion paste: Anhui Keang Nanotechnology Co., Ltd., aerogel content 30%;

[0065] Leveling agent: BYK Chemicals

[0066] Dispersant: BYK Chemicals

[0067] Defoamer: BYK Chemical

[0068] Silicone-acrylic resin: Qingdao Gudao Technology Co., Ltd. BADF, RS-3799A

[0069] Thickeners: BYK Chemical RHEOBYK-425, RHEOBYK-7610;

[0070] Fumed alumina: Cabot Corporation, PC-401; Evonik Degussa, AluC;

[0071] Silane coupling agent: Shanghai Maclean Biochemical Technology Co., Ltd., N-aminoethyl-γ-aminopropyltrimethoxysilane.

[0072] Examples 1-4 A two-component epoxy zinc-aluminum coating

[0073] The two-component epoxy zinc-aluminum coating consists of component A and component B, which are stored separately under normal conditions and mixed evenly when needed. The specific composition of component A and component B is shown in Table 1 (1 part by weight = 1 kg).

[0074] Table 1. Composition (parts by weight) of two-component epoxy zinc-aluminum coatings in Examples 1-4

[0075]

[0076] Examples 5-8 A water-based intumescent fire retardant coating

[0077] The specific composition of the water-based intumescent fire retardant coating is shown in Table 2 (1 part by weight = 1 kg).

[0078] Table 2. Composition (parts by weight) of water-based intumescent fire-retardant coatings in Examples 5-8

[0079]

[0080] Silicone-acrylic resin, melamine, ammonium polyphosphate, pentaerythritol, refractory fiber, silica aerogel dispersion paste, dispersant, defoamer, and titanium dioxide are added sequentially to a mixing tank and stirred at 500 rpm for 60 minutes. Then, fumed alumina, thickener, surface additive, and silane coupling agent are added, and the stirring speed is maintained for another 60 minutes to obtain the final product.

[0081] Comparative Examples 1-5 A two-component epoxy zinc-aluminum coating

[0082] The two-component epoxy zinc-aluminum coating consists of component A and component B, which are stored separately under normal conditions and mixed evenly when needed. The specific compositions of components A and B are shown in Table 3 (1 part by weight = 1 kg). Component A is prepared using the same process as in Example 1.

[0083] Table 3. Composition (parts by weight) of two-component epoxy zinc-aluminum coatings for Comparative Examples 1-5

[0084]

[0085]

[0086] Comparative Examples 6–12 A water-based intumescent fire retardant coating

[0087] The specific composition of the water-based intumescent fire retardant coating is shown in Table 4 (1 part by weight = 1 kg), and it was prepared according to the same process as in Example 5.

[0088] Table 4. Composition (parts by weight) of water-based intumescent fire-retardant coatings for comparative examples 6–12

[0089]

[0090] Test case

[0091] 1. Performance testing of two-component epoxy zinc-aluminum coatings

[0092] The two-component epoxy zinc-aluminum coating was used as the primer for the composite coating of the present invention. Its adhesion to the metal steel surface, impact resistance, flexibility, salt spray resistance and other properties were investigated according to the method shown in Table 5. The results are shown in Table 6.

[0093] Table 5 Performance Indicators and Test Basis of Primer Layer for Composite Coating of Steel Components

[0094] 1 State of components (A and B) in the container Visual inspection 2 Adhesion, MPa GB / T 5210 3 Impact resistance, cm GB / T 1732 4 Flexibility, mm GB / T 6742 5 Salt spray resistance h GB / T 10125 6 Is it cracked? Visual inspection

[0095] Table 6. Performance test results of two-component epoxy zinc-aluminum coatings (primer) for each example and comparative example.

[0096]

[0097] 2. Performance testing of water-based intumescent fire-retardant coatings

[0098] The water-based intumescent fire-retardant coating of the present invention is formed from a water-based intumescent fire-retardant paint. The adhesion, thickness after combustion, and fire resistance limit of the fire-retardant coatings formed by the water-based intumescent fire-retardant paints of Examples 5-8 to the primer layer formed by the two-component epoxy zinc-aluminum paint of Example 1 were investigated according to the method shown in Table 7, and the results are shown in Table 8. The adhesion, thickness after combustion, and fire resistance limit of the fire-retardant coatings formed by the water-based intumescent fire-retardant paints of Comparative Examples 6-12 to the primer layer formed by the two-component epoxy zinc-aluminum paint of Example 1 are shown in Table 9.

[0099] Table 7 Performance Indicators and Test Basis of Fire-Retardant Coatings

[0100] 1 Adhesion, MPa GB / T 5210 2 Thickness, mm GB / T 4956 3 Fire resistance limit, min GB 14907 4 Is it cracked? Visual inspection

[0101] Table 8. Results of performance testing of fire-retardant coatings formed from water-based intumescent fire-retardant coatings in Examples 5-8

[0102]

[0103] Table 9. Results of fire-retardant coating performance tests formed by water-based intumescent fire-retardant coatings of Comparative Examples 6–12

[0104]

[0105] In summary, this invention provides a two-component epoxy zinc-aluminum coating and a water-based intumescent fire-retardant coating, as well as a composite coating comprising a primer layer and a water-based intumescent fire-retardant coating, each cured from the two components. This composite coating is particularly suitable for surface protection of steel structures. The composite coating of this invention exhibits good compatibility between its layers, strong adhesion, and outstanding corrosion resistance and fire resistance, making it especially suitable for fire-retardant composite coatings for steel columns of railway passenger station canopies.

Claims

1. A composite coating comprising a primer layer and a water-based intumescent fire-retardant coating; wherein the primer layer is cured from a two-component epoxy zinc-aluminum coating, the two-component epoxy zinc-aluminum coating comprising component A and component B, which are normally stored separately and mixed when used, wherein the weight ratio of component A to component B is 4~6:1; in, Component A consists of the following components in parts by weight: 30-35 parts of waterborne epoxy resin emulsion, 60-70 parts of zinc-aluminum alloy powder, 0.5-1.0 parts of fumed silica, 2-4 parts of silica aerogel dispersion paste, 1-1.5 parts of bentonite, 2-4 parts of leveling agent, 2-4 parts of dispersant, and 0.5-1 parts of defoamer; The aqueous epoxy resin emulsion is selected from the brand name Epikote. TM 3520-WY-55A and Epikote TM The product is one of the waterborne epoxy resin emulsions 3522-W-60A; based on the total mass of the zinc-aluminum alloy powder, the percentage content of zinc is 78-88%, and the balance is aluminum; the fumed silica is selected from one of AEROSIL® 200, AEROSIL® 300, and AEROSIL® 380; the dispersant is selected from one of BYK®-151 and BYK®-155; the leveling agent is BYK®-333; and the defoamer is selected from one of BYK®-024 and Daejeon Chemical D-80. Component B is diethylenetriamine or triethylenetetraamine; The water-based intumescent fire-retardant coating is cured from a water-based intumescent fire-retardant paint; the water-based intumescent fire-retardant paint is composed of the following components in parts by weight: The composition includes 35-45 parts silicone-acrylic resin, 8-12 parts melamine, 20-28 parts ammonium polyphosphate, 8-14 parts pentaerythritol, 0.5-2 parts refractory fiber, 8-18 parts silica aerogel dispersion, 0.5-2 parts fumed alumina, 1-2 parts thickener, 1-2 parts dispersant, 1-2 parts film-forming aid, 0.5-2 parts defoamer, 2-8 parts titanium dioxide, and 0.5-1.5 parts silane coupling agent; wherein the silicone-acrylic resin is selected from commercially available silicone-acrylic resin produced by Qingdao Gudao Technology Co., Ltd. The refractory fiber is made of aluminosilicate fiber with a length <1cm and a refractory temperature >800℃; the thickener is selected from RHEOBYK-425 or RHEOBYK-7610; the dispersant is selected from water-based wetting and dispersing agent BYK®-190 or BYK®-9076; the film-forming aid is dodecyl alcohol ester; the titanium dioxide is rutile titanium dioxide with a particle size of 45~80μm; and the defoamer is BYK®-018.

2. The composite coating according to claim 1, characterized in that, The dry film thickness of the primer layer is 80~100μm; the dry film thickness of the water-based intumescent fire retardant coating is 1-5mm.

3. The composite coating according to claim 1, characterized in that, The zinc-aluminum alloy powder has a particle size of 300 mesh.

4. The composite coating according to claim 1, characterized in that, The silica aerogel dispersion contains 20% or 30% silica aerogel.

5. The composite coating according to claim 1, characterized in that, The preparation method of component A includes the following operations: Prepare each raw material component according to the formula; add the water-based epoxy resin emulsion, dispersant and defoamer to a container equipped with a stirring device and stir for 10-20 minutes; add bentonite, silica aerogel dispersion paste and fumed silica, maintain the speed and stir for 20-40 minutes; finally add zinc aluminum alloy powder and leveling agent, stir evenly to obtain component A.

6. The composite coating according to claim 5, characterized in that, The stirring speed is 400-600 rpm.

7. The composite coating according to claim 1, characterized in that, The water-based intumescent fire-retardant coating is composed of the following components in parts by weight: The ingredients are: 38-42 parts silicone-acrylic resin, 8-12 parts melamine, 20-28 parts ammonium polyphosphate, 10-14 parts pentaerythritol, 1-2 parts refractory fiber, 8-18 parts silica aerogel dispersion paste, 1-2 parts fumed alumina, 1-2 parts thickener, 1-2 parts dispersant, 1-2 parts film-forming aid, 0.5-2 parts defoamer, 4-6 parts titanium dioxide, and 1-1.5 parts silane coupling agent.

8. The composite coating according to claim 1 or 7, characterized in that, In the raw materials of the water-based intumescent fire retardant coating, the particle size of the fumed alumina is 100~300nm.

9. The composite coating according to claim 1 or 7, characterized in that, The preparation method of the water-based intumescent fire-retardant coating includes the following steps: Prepare the raw materials according to the formula; add the silicone acrylic resin, melamine, ammonium polyphosphate, pentaerythritol, refractory fiber, silica aerogel dispersion paste, dispersant, defoamer and titanium dioxide to the equipment equipped with a stirring device in sequence, and stir for 60~100min; then add fumed alumina, thickener, film-forming aid and silane coupling agent, and continue stirring for 60~100min to obtain the final product.

10. The composite coating according to claim 9, characterized in that, The stirring speed is 400~600 rpm.

11. The composite coating according to claim 1, characterized in that, The composite coating also includes a topcoat layer, and the water-based intumescent fire-retardant coating is located between the topcoat layer and the primer layer.

12. The composite coating according to claim 11, characterized in that, The topcoat layer is formed by curing fluorocarbon resin coatings or polyurethane coatings.

13. The application of the composite coating according to any one of claims 1 to 12 in the coating of steel components.

14. The application of the composite coating according to any one of claims 1 to 12 in the coating of steel columns for railway passenger station canopies.

15. A construction process for coating the surface of steel components, comprising using a two-component epoxy zinc-aluminum coating as a primer and a water-based intumescent fire-retardant coating as a fire-retardant coating, wherein the two-component epoxy zinc-aluminum coating is as defined in any one of claims 1 to 6, and the water-based intumescent fire-retardant coating is as defined in claims 1, 7, 8, 9, or 10; the construction process comprises the following steps: S1. Clean and remove rust from the surface of the steel components that need to be painted, so that the surface reaches Sa2.5 grade or above; S2. Mix component A and component B evenly according to the weight ratio, spray or brush onto the surface with Sa2.5 grade or above, let it dry naturally, and repeat spraying or brushing until the dry film thickness reaches 80~100μm; S3. Spray or brush the water-based intumescent fire retardant coating onto the primer layer obtained in step S2, and allow it to dry naturally; repeat the spraying or brushing until the dry film thickness reaches 1~5mm.

16. The construction process according to claim 15, characterized in that, The construction process, following step S3, further includes: S4. Spray or brush the fluorocarbon resin coating or polyurethane coating onto the fireproof coating obtained in step S3, and allow it to dry naturally; repeat the spraying or brushing until the dry film reaches the specified thickness.

Images