Gypsum-based fireproof heat-insulating coating for fabricated building steel member and coating method of gypsum-based fireproof heat-insulating coating

Abstract

The invention relates to the technical field of steel structure flame-retardant materials, in particular to a gypsum-based fireproof heat-preservation coating for fabricated building steel members and a coating method, and the gypsum-based fireproof heat-preservation coating comprises the following components: 25-35 parts of gypsum, 8-12 parts of slag, 8-12 parts of cement, 3-7 parts of silica fume, 15-25 parts of expanded perlite, 15-25 parts of vitrified micro bubbles, 0.8-1.2 parts of methyl cellulose and 3-5 parts of glass fibers. A composite base material is formed by gypsum, slag, cement, silica fume and other raw materials, so that the hardness and durability of a coating layer of the coating are improved while the fire resistance and the heat preservation property are ensured.

Description

Technical Field

[0001] The present invention belongs to the technical field of flame-retardant materials for steel structures, and specifically relates to a gypsum-based fireproof and thermal insulation coating for assembled building steel components and a coating method. Background Art

[0002] Steel is a non-flammable building material. Compared to concrete, steel offers numerous advantages, such as earthquake resistance and bending resistance, making it widely used in modern architecture. While non-flammable, steel can deform when exposed to high temperatures, leading to structural collapse. However, steel as a building material also has some unavoidable fire-resistant flaws. Unprotected steel structures generally have a fire resistance limit of approximately 15 minutes. At temperatures between 450°C and 650°C, they lose their load-bearing capacity, undergoing significant deformation, leading to bending of steel columns and beams and even structural collapse. Therefore, to extend escape and rescue time in the event of a fire, steel structures must be coated with fire-retardant coatings.

[0003] Traditional fire-retardant coatings for steel structures are primarily cement-based, which presents inherent drawbacks such as high bulk, susceptibility to cracking, and manual application. Cement-based coatings require on-site layered application and exhibit poor adhesion to steel, requiring additional meshing or primer application, resulting in complex processes and long application times. Furthermore, traditional cement-based fire-retardant coatings are not environmentally friendly.

[0004] In recent years, gypsum-based fire-retardant coatings have gradually replaced cement-based products due to their advantages such as light weight, good flexibility and fast construction, but they still face problems of low compressive strength and insufficient adhesion. Summary of the Invention

[0005] In order to solve the problems raised in the background technology, the present invention proposes a gypsum-based fireproof and thermal insulation coating for prefabricated building steel components and a coating method to solve the above problems.

[0006] A gypsum-based fireproof and thermal insulation coating for prefabricated building steel components comprises the following components: 25-35 parts of gypsum, 8-12 parts of slag, 8-12 parts of cement, 3-7 parts of silica fume, 15-25 parts of expanded perlite, 15-25 parts of glass microspheres, 0.8-1.2 parts of methyl cellulose, and 3-5 parts of glass fiber.

[0007] By adjusting the gypsum ratio and the composite base material system, the fire resistance time is further extended, which is significantly higher than that of traditional gypsum-based coatings. Silica fume fills the micropores, reducing the risk of cracking and falling off of the coating at high temperatures.

[0008] The gypsum is building gypsum or desulfurized gypsum, and the bulk density of the expanded perlite and the vitrified microspheres are 80-150 kg / m 3 , volume water absorption rate ≤50%; the glass fiber length is 3 to 12 mm, and the diameter is 10 to 20 μm.

[0009] The methyl cellulose is hydroxypropyl methyl cellulose ether with a viscosity range of 15,000 to 60,000 mPa·s, and is used to improve the water retention and workability of the coating. The surface of the glass fiber is treated with a silane coupling agent to enhance the adhesion with the base material.

[0010] The closed porosity of the expanded pearlite is ≥90%, and the thermal conductivity is ≤0.05W / (m·K); the particle size of the vitrified microbeads is 0.5-2mm, and the thickness of the surface vitrified layer is ≥50μm.

[0011] The silica fume is microsilica powder with a particle size of ≤1μm and a specific surface area of ≥15m 2 / g, used to fill the micropores in the coating and reduce shrinkage cracking.

[0012] It also includes one or more of the following auxiliary components:

[0013] Retarder: sodium citrate or sodium tripolyphosphate, added in an amount of 0.1 to 0.5 parts;

[0014] Air entraining agent: sodium alkylbenzene sulfonate, the addition amount is 0.01-0.1 parts;

[0015] Redispersible latex powder: ethylene / vinyl acetate copolymer, added in an amount of 0.1 to 1 part.

[0016] The coating is a powdery mixture. During construction, the mass ratio of water to coating is 0.8 to 0.9. After stirring, a colloid is formed and the coating is applied to the surface of the steel component by a combination of spraying and troweling. The total coating thickness is 20 to 30 mm.

[0017] Existing gypsum-based coatings are mostly single-performance oriented, such as fire resistance or thermal insulation. This formula achieves differentiated applications through three ratio types:

[0018] High fireproof type, gypsum 35 parts, slag 12 parts, cement 12 parts, silica fume 3 parts, expanded perlite 15 parts, vitrified microspheres 15 parts, fire resistance ≥ 2 hours, bulk density ≤ 800kg / m 3 . Applicable to high-risk areas such as core tubes;

[0019] Lightweight thermal insulation type, 25 parts gypsum, 8 parts slag, 8 parts cement, 7 parts silica fume, 25 parts expanded perlite, 25 parts vitrified microspheres, thermal conductivity ≤ 0.08W / (m·K), bulk density ≤ 600kg / m 3 . Suitable for lightweight scenarios such as roofing;

[0020] Balanced general-purpose type, composed of 30 parts gypsum, 10 parts slag, 10 parts cement, 5 parts silica fume, 20 parts expanded perlite, and 20 parts vitrified microspheres. It has a fire resistance of ≥1.8 hours and a thermal conductivity of ≤0.1W / (m·K). It covers general scenarios such as beams and columns. 17

[0021] Able to flexibly adapt to different engineering needs.

[0022] A method for spraying a gypsum-based fireproof and thermal insulation coating for assembled building steel components comprises the following steps:

[0023] (1) Surface pretreatment of steel components: complete anti-corrosion treatment and lay steel mesh with a specification of 0.8-1 mm;

[0024] (2) Coating preparation: Mix the powder with water at a water-cement ratio of 0.8 to 0.9 and stir until a uniform colloid is formed;

[0025] (3) Coating process: first spray a 15-20 mm thick base layer, then apply a 5-10 mm thick surface layer for leveling;

[0026] (4) Maintenance: Allow to dry naturally for 24 to 48 hours to form a dense, hollow-free fireproof and thermal insulation coating.

[0027] The spraying is carried out using airless spraying equipment with a pressure of ≥10 MPa; the smearing is carried out using a stainless steel spatula in two steps, with a thickness of ≤5 mm each time.

[0028] When making fire-retardant coatings, the water-cement ratio is 0.8, and when making thermal insulation coatings, the water-cement ratio is 0.9.

[0029] The layered process of spraying first and then smearing is adopted, combined with dynamic water-cement ratio adjustment to optimize the coating density and surface smoothness. Compared with traditional single-layer spraying, it reduces the risk of hollowing and improves construction efficiency.

[0030] The slag, desulfurization gypsum, etc. in the formula are all industrial by-products, which further reduce production costs and reduce environmental burden.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] 1. Existing gypsum-based coatings are mostly based on a single component of gypsum. The formula of the present invention adopts a composite base material system of gypsum, slag, cement, and silica fume. The addition of slag and cement significantly improves the hardness and durability of the coating, and silica fume fills micropores, reducing the risk of shrinkage cracking.

[0033] 2. Traditional formulations often use polystyrene polymers or vermiculite as thermal insulation materials. The present invention adopts a dual aggregate system of expanded perlite and vitrified microspheres. The closed porosity of the vitrified microspheres is ≥90% and the thermal conductivity is ≤0.05W / (m·K), which is superior to ordinary expanded vermiculite, significantly improving thermal insulation efficiency. The aggregate is lightweight, with a bulk density of ≤600-800kg / m 3 At the same time, it takes into account high thermal insulation performance and is suitable for the lightweight needs of prefabricated buildings.

[0034] 3. Methylcellulose is added as a water-retaining agent to improve leveling during construction; glass fiber is treated with a silane coupling agent to enhance crack resistance. Furthermore, optional retarders such as sodium citrate and air-entraining agents can be added to address the conflict between the setting speed and subsequent strength of traditional gypsum coatings. Through refined additive adjustments, coating density and long-term durability can be enhanced. DETAILED DESCRIPTION

[0035] In order to make the purpose, technical solutions and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0036] Example 1

[0037] A gypsum-based fireproof and thermal insulation coating for prefabricated building steel components, comprising the following components in weight ratio: 35% gypsum, which is construction gypsum or desulfurized gypsum with a purity of 95% or higher; 12% slag, with an active SiO2 and Al2O3 content of 80% or higher; 12% ordinary Portland cement with a strength grade of 42.5; and 3% silica fume with a particle size of 1 μm or less and a specific surface area of 15 m or higher. 2 / g; expanded perlite: 15%, bulk density 80-120kg / m 3 , closed porosity ≥ 90%; glass microspheres: 15%, particle size 0.5~2mm, thermal conductivity ≤ 0.05W / (m·K); methyl cellulose: 0.8%, hydroxypropyl methyl cellulose ether, viscosity 15,000~60,000 mPa·s; glass fiber: 4%, length 3~12mm, treated with silane coupling agent.

[0038] Fire resistance ≥ 2 hours, compressive strength ≥ 40MPa; bulk density ≤ 800kg / m 3 , bonding strength ≥1.5MPa; suitable for high-rise building core tubes, fire walls and other areas with high fire protection requirements.

[0039] Example 2

[0040] A gypsum-based fireproof and thermal insulation coating for prefabricated building steel components, comprising the following components in weight ratio: 25% gypsum, which is construction gypsum or desulfurized gypsum with a purity of 95% or higher; 8% slag, with an active SiO2 and Al2O3 content of 80% or higher; 8% ordinary Portland cement with a strength grade of 42.5; and 7% silica fume with a particle size of 1 μm or less and a specific surface area of 15 m or higher. 2 / g; expanded perlite: 25%, bulk density ≤120kg / m 3, closed porosity ≥ 90%; glass microspheres: 25%, particle size 0.5~2mm, thermal conductivity ≤ 0.06W / (m·K); methyl cellulose: 1.2%, water retention ≥ 95%; glass fiber: 3%, length 3~12mm, treated with silane coupling agent.

[0041] Thermal conductivity ≤0.08W / (m·K), bulk density ≤600kg / m 3 ; Fire resistance ≥ 1.5 hours, drying shrinkage ≤ 0.05%;

[0042] It is suitable for prefabricated buildings such as light steel roofs and partition walls that are sensitive to weight and require certain insulation requirements.

[0043] Example 3

[0044] A gypsum-based fireproof and thermal insulation coating for prefabricated building steel components, comprising the following components in weight ratio: 30% gypsum, which is construction gypsum or desulfurized gypsum with a purity of 95% or higher; 10% slag, with an active SiO2 and Al2O3 content of 80% or higher; 10% ordinary Portland cement with a strength grade of 42.5; and 5% silica fume with a particle size of 1 μm or less and a specific surface area of 15 m or higher. 2 / g; expanded perlite: 20%, bulk density 80-120kg / m 3 , closed porosity ≥ 90%; glass microspheres: 20%, particle size 0.5-2mm, thermal conductivity ≤ 0.05W / (m·K); methyl cellulose: 1.0%, hydroxypropyl methyl cellulose ether, viscosity 15,000-60,000 mPa·s; glass fiber: 4%, length 3-12mm, treated with silane coupling agent.

[0045] Fire resistance ≥ 1.8 hours, thermal conductivity ≤ 0.1W / (m·K); compressive strength ≥ 35MPa, bonding strength ≥ 1.2MPa;

[0046] Applicable scenarios: general steel structure components such as beams and columns.

[0047] Example 4

[0048] A gypsum-based fireproof and thermal insulation coating for prefabricated building steel components comprises the following components: 25-35 parts of gypsum, 8-12 parts of slag, 8-12 parts of cement, 3-7 parts of silica fume, 15-25 parts of expanded perlite, 15-25 parts of glass microspheres, 0.8-1.2 parts of methyl cellulose, and 3-5 parts of glass fiber.

[0049] The gypsum is building gypsum or desulfurized gypsum, and the bulk density of the expanded perlite and the vitrified microspheres are 80-150 kg / m 3 , volume water absorption rate ≤50%; the glass fiber length is 3 to 12 mm, and the diameter is 10 to 20 μm.

[0050] The methyl cellulose is hydroxypropyl methyl cellulose ether with a viscosity ranging from 15,000 to 60,000 mPa·s; the surface of the glass fiber is treated with a silane coupling agent.

[0051] The closed porosity of the expanded pearlite is ≥90%, and the thermal conductivity is ≤0.05W / (m·K); the particle size of the vitrified microbeads is 0.5-2mm, and the thickness of the surface vitrified layer is ≥50μm.

[0052] The silica fume is microsilica powder with a particle size of ≤1μm and a specific surface area of ≥15m 2 / g, used to fill the micropores in the coating and reduce shrinkage cracking.

[0053] It also includes one or more of the following auxiliary components:

[0054] Retarder: sodium citrate or sodium tripolyphosphate, added in an amount of 0.1 to 0.5 parts;

[0055] Air entraining agent: sodium alkylbenzene sulfonate, the addition amount is 0.01-0.1 parts;

[0056] Redispersible latex powder: ethylene / vinyl acetate copolymer, added in an amount of 0.1 to 1 part.

[0057] The coating is a powdery mixture. During construction, the mass ratio of water to coating is 0.8 to 0.9. After stirring, a colloid is formed and the coating is applied to the surface of the steel component by a combination of spraying and troweling. The total coating thickness is 20 to 30 mm.

[0058] A method for spraying a gypsum-based fireproof and thermal insulation coating for assembled building steel components comprises the following steps:

[0059] (1) Surface pretreatment of steel components: complete anti-corrosion treatment and lay steel mesh with a specification of 0.8-1 mm;

[0060] (2) Coating preparation: Mix the powder with water at a water-cement ratio of 0.8 to 0.9 and stir until a uniform colloid is formed;

[0061] (3) Coating process: first spray a 15-20 mm thick base layer, then apply a 5-10 mm thick surface layer for leveling;

[0062] (4) Maintenance: Allow to dry naturally for 24 to 48 hours to form a dense, hollow-free fireproof and thermal insulation coating.

[0063] The spraying is carried out using airless spraying equipment with a pressure of ≥10 MPa; the smearing is carried out using a stainless steel spatula in two steps, with a thickness of ≤5 mm each time.

[0064] When making fire-retardant coatings, the water-cement ratio is 0.8, and when making thermal insulation coatings, the water-cement ratio is 0.9.

[0065] 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 invention can be embodied in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as illustrative and non-restrictive, and the scope of the invention is defined by the appended claims rather than the foregoing description, and it is intended that all variations that come within the meaning and range of equivalents of the claims be embraced therein.

[0066] In addition, it should be understood that although this specification is described in terms of implementation methods, not every implementation method contains only one independent technical solution. This narrative method 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 can also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

Claims

1. A gypsum-based fireproof and thermal insulation coating for assembled building steel components, characterized in that: The invention comprises the following components: 25-35 parts of gypsum, 8-12 parts of slag, 8-12 parts of cement, 3-7 parts of silica fume, 15-25 parts of expanded perlite, 15-25 parts of vitrified microspheres, 0.8-1.2 parts of methyl cellulose and 3-5 parts of glass fiber.

2. The gypsum-based fireproof and thermal insulation coating for prefabricated building steel components according to claim 1, characterized in that: The gypsum is building gypsum or desulfurized gypsum, and the bulk density of the expanded perlite and the vitrified microspheres are 80-150 kg / m 3 , volume water absorption rate ≤50%; the glass fiber length is 3 to 12 mm, and the diameter is 10 to 20 μm.

3. The gypsum-based fireproof and thermal insulation coating for prefabricated building steel components according to claim 1, characterized in that: The methyl cellulose is hydroxypropyl methyl cellulose ether with a viscosity ranging from 15,000 to 60,000 mPa·s; the surface of the glass fiber is treated with a silane coupling agent.

4. The gypsum-based fireproof and thermal insulation coating for prefabricated building steel components according to claim 1, characterized in that: The closed porosity of the expanded pearlite is ≥90%, and the thermal conductivity is ≤0.05W / (m·K); the particle size of the vitrified microbeads is 0.5-2mm, and the thickness of the surface vitrified layer is ≥50μm.

5. The gypsum-based fireproof and thermal insulation coating for assembled building steel components according to claim 1, characterized in that: The silica fume is microsilica powder with a particle size of ≤1μm and a specific surface area of ≥15m 2 / g, used to fill the micropores in the coating and reduce shrinkage cracking.

6. The gypsum-based fireproof and thermal insulation coating for assembled building steel components according to claim 1, characterized in that: It also includes one or more of the following auxiliary components: Retarder: sodium citrate or sodium tripolyphosphate, added in an amount of 0.1 to 0.5 parts; Air entraining agent: sodium alkylbenzene sulfonate, the addition amount is 0.01-0.1 parts; Redispersible latex powder: ethylene / vinyl acetate copolymer, added in an amount of 0.1 to 1 part.

7. The gypsum-based fireproof and thermal insulation coating for prefabricated building steel components according to claim 1, characterized in that: The coating is a powdery mixture, which forms a colloid after stirring and is applied to the surface of the steel component through a combination of spraying and smearing processes, with a total coating thickness of 20 to 30 mm.

8. A method for spraying gypsum-based fireproof and thermal insulation coatings for assembled building steel components, characterized in that: The following steps are involved: (1) Surface pretreatment of steel components: complete anti-corrosion treatment and lay steel mesh with a specification of 0.8-1 mm; (2) Coating preparation: Mix the powder with water at a water-cement ratio of 0.8 to 0.9 and stir until a uniform colloid is formed; (3) Coating process: first spray a 15-20 mm thick base layer, then apply a 5-10 mm thick surface layer for leveling; (4) Maintenance: Allow to dry naturally for 24 to 48 hours to form a dense, hollow-free fireproof and thermal insulation coating.

9. A method for spraying a gypsum-based fireproof and thermal insulation coating for assembled building steel components according to claim 8, characterized in that: The spraying is carried out using airless spraying equipment with a pressure of ≥10 MPa; the smearing is carried out using a stainless steel spatula in two steps, with a thickness of ≤5 mm each time.

10. The method for spraying a gypsum-based fireproof and thermal insulation coating for prefabricated building steel components according to claim 8, characterized in that: When making fire-retardant coatings, the water-cement ratio is 0.8, and when making thermal insulation coatings, the water-cement ratio is 0.9.