Lightweight gypsum-based fireproof coating and preparation method thereof

Abstract

The application belongs to the field of refractory materials, in particular to the field of C04B28, and more particularly to a light gypsum-based fireproof coating and a preparation method thereof. The preparation raw materials of the fireproof coating include, in terms of mass fraction, 58-62 parts of gypsum powder, 8-10 parts of sepiolite, 4-6 parts of mica flake, 20-25 parts of perlite, 0.1-0.5 parts of thixotropic lubricant, 0.3-0.8 parts of anti-cracking fiber, 0.8-1.2 parts of adhesive, and 0.1-0.3 parts of retarder. The gypsum-based fireproof coating obtained by the application has excellent adhesive performance, the adhesive strength is not less than 0.06 MPa, and has low dry density and bulk density. In addition, the drying time, anti-cracking test, heat resistance test, moisture resistance test, and freezing resistance test detection items all meet the national standards, and have excellent actual use effect.

Description

Technical Field

[0001] This invention belongs to the field of refractory materials, particularly to C04B28, and more specifically to a lightweight gypsum-based fire-retardant coating and its preparation method. Background Technology

[0002] Fires severely endanger people's lives and property, and effective fire prevention measures can significantly reduce their harm. Fire-retardant coatings typically refer to building coatings with excellent flame-retardant properties. Applying fire-retardant coatings to the surface of flammable materials can block direct contact with flames, slow down the spread of flames on the substrate surface, delay or reduce the combustion time, thereby inhibiting the spread of fire. Suitable fire-retardant coatings also have multiple functions such as oxidation resistance, chemical corrosion resistance, and smoke prevention. In addition, from a commercial perspective, fire-retardant coatings with decorative and aesthetic functions are currently more popular with downstream customers. At present, cement-based fire-retardant coatings dominate the fire-retardant coating market. Cement-based fire-retardant coatings have high hardness and durability, but their susceptibility to cracking, hollowing, and difficulty in processing and molding still limit their application range to some extent. In addition, cement is a high-resource-consuming, high-energy-consuming, and high-polluting material. Currently, the use of gypsum-based fire-retardant coatings in refractory materials is increasing.

[0003] Existing technology CN107760070B discloses a gypsum-based flame-retardant fireproof coating and its preparation method. This fireproof coating, by weight, comprises: 70-90 parts gypsum powder; 2-20 parts cellulose; 1-5 parts polystyrene; 1-10 parts calcium carbonate; 1-5 parts foaming agent; 1-3 parts retarder; and 0.1-1 parts graphene. The product exhibits excellent fire resistance and low oxygen index and smoke density. The calcium carbonate component enhances mechanical and flame-retardant properties. However, according to the national standard GB / T 14907-2018, the dry density of indoor fireproof materials should not exceed 500 kg / m³. 3 This gypsum-based fire retardant coating is difficult to apply indoors. In addition, adhesive strength is also one of the important performance indicators for gypsum-based fire retardant coatings. Summary of the Invention

[0004] To address the aforementioned technical problems, the first aspect of this invention provides a lightweight gypsum-based fire-retardant coating, the raw materials of which, by mass parts, comprise: 58-62 parts gypsum powder, 8-10 parts sepiolite, 4-6 parts mica flakes, 20-25 parts perlite, 0.1-0.5 parts thixotropic lubricant, 0.3-0.8 parts crack-resistant fiber, 0.8-1.2 parts binder, and 0.1-0.3 parts retarder.

[0005] More preferably, the lightweight preparation raw materials include, by weight parts: 60 parts gypsum powder, 9 parts sepiolite, 5 parts mica flakes, 24 parts perlite, 0.4 parts thixotropic lubricant, 0.5 parts crack-resistant fiber, 1 part adhesive, and 0.1 parts retarder.

[0006] gypsum powder

[0007] Preferably, the gypsum powder includes one or more of phosphogypsum powder, desulfurized gypsum powder, citric acid gypsum powder, or fluorogypsum powder.

[0008] More preferably, the gypsum powder includes desulfurized gypsum powder.

[0009] Preferably, the desulfurized gypsum powder includes one of hemihydrate gypsum, anhydrous gypsum, and dihydrate gypsum.

[0010] More preferably, the desulfurized gypsum powder includes hemihydrate gypsum; as an implementable example, the desulfurized gypsum powder can be β-hemihydrate gypsum, purchased from Zhejiang Gusi Construction Technology Co., Ltd.

[0011] sepiolite

[0012] Preferably, the sepiolite has a particle size of 100-1500 mesh; as an implementable example, the particle size of the sepiolite includes one of 100, 200, 300, 325, 800, and 1250.

[0013] More preferably, the sepiolite has a particle size of 300 mesh; as an implementable example, the 300-mesh sepiolite can be purchased from Shijiazhuang Tianyuan Mining Co., Ltd.

[0014] mica sheets

[0015] Preferably, the mica sheet has a mesh size of 10-80 mesh.

[0016] More preferably, the mica sheet has a mesh size of 10-40 mesh; as an example, the mica sheet can be purchased from Lingshou County Yanhong Mineral Products Processing Plant.

[0017] perlite

[0018] Preferably, the perlite has a particle size of 10-70 mesh; as an implementable example, the perlite particle size includes 10-20 mesh, 20-30 mesh, 30-50 mesh, and 50-70 mesh.

[0019] More preferably, the perlite has a particle size of 20-30 mesh and 30-50 mesh.

[0020] More preferably, the mass ratio of the 20-30 mesh perlite to the 30-50 mesh perlite is (7-9):(15-17).

[0021] Thixotropic lubricant

[0022] This invention does not impose too many limitations on thixotropic lubricants; any additive that can improve the feel of fire-retardant coatings is acceptable, including but not limited to TSCB-21000 produced by Shandong Tiansheng Cellulose Co., Ltd.

[0023] Crack-resistant fiber

[0024] Preferably, the length of the crack-resistant fiber is 6-25 mm.

[0025] More preferably, the length of the crack-resistant fiber is 6mm; as an implementable example, the 6mm crack-resistant fiber can be purchased from Zibo Longen Fiber Co., Ltd.

[0026] adhesive

[0027] This invention does not impose too many limitations on adhesives; any substance that can improve the bonding strength of gypsum-based fire-retardant coatings is acceptable, including but not limited to 6010 produced by Anhui Wanwei New Materials Co., Ltd.

[0028] Retarder

[0029] This invention does not impose too many restrictions on retarders; any substance that can improve the retarding performance of gypsum-based fire-retardant coatings is acceptable, including but not limited to 200P produced by Shanghai Sika Chemical Co., Ltd.

[0030] Compared to commonly available cement-based fire-retardant coatings, gypsum-based fire-retardant coatings are less prone to cracking and have better stability. Therefore, the inventors replaced cement with desulfurized gypsum powder and used desulfurized gypsum powder combined with heavy calcium carbonate as the base gel powder for the fire-retardant coating. However, in actual research and development, it was found that the gypsum-based coating cracked during the hardening process, had a high dry density, and an unsatisfactory bulk density. According to the national standard GB / T14907-2018, the dry density of indoor fire-retardant materials should not exceed 500 kg / m³. 3After repeated testing, it was found that the high content of heavy calcium carbonate in the formula was the main cause of cracking. Therefore, the heavy calcium carbonate in the original formula was removed, and desulfurized gypsum powder was used as the only basic cementitious powder. This could reduce the dry density and bulk density of the gypsum-based fire retardant coating to some extent. However, in practice, it still did not meet the requirements of the national standard for dry density and bulk density. The inventors unexpectedly discovered that when sepiolite and crack-resistant fiber were added to the preparation system, especially the combination of 300-mesh sepiolite and 6mm crack-resistant fiber, not only was the compatibility in the raw material system high, but also no agglomeration or dispersion occurred during stirring, which greatly improved the structural stability of the gypsum-based fire retardant coating and significantly reduced the dry density of the gypsum-based coating. The inventors also found that when 8-10 parts of sepiolite and 0.3-0.8 parts of crack-resistant fiber were selected, and the mass fraction of desulfurized gypsum powder was controlled at 58-62 parts, the stability of the gypsum-based fire retardant coating was stronger while maintaining the integrity of the total weight of the formula, and the dry density could be further reduced. The current national standard for the bonding strength of gypsum-based coatings is not less than 0.04 MPa. This invention aims to provide a product with a bonding strength of not less than 0.06 MPa. The inventors have discovered that when the mass fraction of the adhesive is limited to not less than 0.8 parts, especially between 0.8 and 1.2 parts, not only can the bonding strength be guaranteed to be not less than 0.06 MPa, but also the raw materials can be uniformly dispersed, highly stable, the finished product can be smoothly sprayed without sagging, the thickness can be well controlled, and the construction can be simple. In addition, to further improve the mechanical stability of the coating and reduce color difference issues when this gypsum-based fire-retardant coating is applied indoors, the inventors selected white or beige perlite filler, especially a mixture of 20-30 mesh perlite and 30-50 mesh perlite at a mass ratio of (7-9):(15-17). With the combined action of 300 mesh mica flakes and a thixotropic lubricant, it not only maintains low dry and bulk density but also exhibits excellent initial crack resistance, resistance to damp heat, and freeze-thaw resistance. No color difference occurs when applied indoors, demonstrating excellent practical performance. The components and dosage of the retarder can be reasonably adjusted according to the required drying performance in the actual preparation of the fire-retardant coating, and normal use is sufficient.

[0031] A second aspect of this invention provides a method for preparing a lightweight gypsum-based fire-retardant coating, comprising the following steps:

[0032] S1. Add the gypsum powder, adhesive, thixotropic lubricant, and retarder to a horizontal zero-gravity mixer according to the mass proportions, and stir and mix for no less than 15 minutes until uniform.

[0033] S2. Then, sepiolite, mica flakes, and crack-resistant fibers are sequentially added into a horizontal zero-gravity mixer and stirred for at least 20 minutes until homogeneous.

[0034] S3. Put all the perlite into a horizontal zero-gravity mixer and mix for no more than 5 minutes. Then process and package for use.

[0035] A further preferred embodiment of the method for preparing the lightweight gypsum-based fire-retardant coating includes the following steps:

[0036] S1. Add the gypsum powder, adhesive, thixotropic lubricant, and retarder to a horizontal zero-gravity mixer according to the mass fractions, and stir for 30 minutes until uniform.

[0037] S2. Then, sepiolite, mica flakes, and crack-resistant fibers are added sequentially to a horizontal zero-gravity mixer. The sepiolite and crack-resistant fibers should be added slowly to ensure uniform dispersion. Stir and mix for 30 minutes until homogeneous.

[0038] S3. Put all the 20-30 mesh and 30-50 mesh perlite into a horizontal zero-gravity mixer and mix for 3 minutes. Then process and package for use.

[0039] Beneficial effects

[0040] (i) The gypsum-based fireproof coating obtained by the present invention has excellent adhesion properties and an adhesion strength of less than 0.06 MPa.

[0041] (ii) The gypsum-based fireproof coating obtained by the present invention has a low dry density and bulk density, which meets the relevant requirements of the national standard GB / T14907-2018.

[0042] (III) When the gypsum-based fireproof coating obtained by this invention is applied indoors, it has a low color difference and a certain decorative effect.

[0043] (iv) By controlling the composition and mass fraction of the raw materials, especially when the raw materials are 58-62 parts desulfurized gypsum powder, 8-10 parts sepiolite, 4-6 parts mica flakes, 20-25 parts perlite, 0.1-0.5 parts thixotropic lubricant, 0.3-0.8 parts crack-resistant fiber, 0.8-1.2 parts binder, and 0.1-0.3 parts retarder, this invention can ensure that the drying time, crack resistance test, heat resistance test, moisture resistance test, and freeze resistance test of the gypsum-based fireproof coating all meet the national standards. Among them, the bonding strength test reaches 0.07 MPa at an ambient temperature of 25℃ and 0.09 MPa at an ambient temperature of 35℃.

[0044] (V) The gypsum-based fireproof coating obtained by this invention has good workability, good workability after being mixed with various types of mixers, smooth spraying, no dripping, high thickness control, and bonding strength that meets the customer's performance requirements. It has already entered the mass production stage. Detailed Implementation

[0045] Example 1

[0046] The first aspect of this example provides a lightweight gypsum-based fire-retardant coating, the raw materials of which are, by mass parts: 60 parts desulfurized gypsum powder, 9 parts sepiolite, 5 parts mica flakes, 24 parts perlite, 0.4 parts thixotropic lubricant, 0.5 parts crack-resistant fiber, 1 part adhesive, and 0.1 parts retarder.

[0047] The desulfurized gypsum powder is β-hemihydrate gypsum, purchased from Zhejiang Gusi Construction Technology Co., Ltd.

[0048] The sepiolite in question has a mesh size of 300 and was purchased from Shijiazhuang Tianyuan Mining Co., Ltd.

[0049] The mica sheets were 20-40 mesh and were purchased from Lingshou County Yanhong Mineral Products Processing Plant.

[0050] The perlite in question has a mesh size of 20-30 mesh and 30-50 mesh, with a mass ratio of 3:5, and was purchased from Xinyang Jinhua Lan Mining Co., Ltd.

[0051] The thixotropic lubricant mentioned is TSCB-21000 produced by Shandong Tiansheng Cellulose Co., Ltd.

[0052] The anti-crack fiber has a length of 6mm and was purchased from Zibo Longen Fiber Co., Ltd.

[0053] The adhesive mentioned is 6010 produced by Anhui Wanwei New Materials.

[0054] The retarder mentioned is 200P produced by Shanghai Sika Chemical Co., Ltd.

[0055] The second aspect of this example provides a method for preparing a lightweight gypsum-based fire-retardant coating, specifically comprising the following steps:

[0056] S1. Add the gypsum powder, adhesive, thixotropic lubricant, and retarder to a horizontal zero-gravity mixer according to the mass fractions, and stir for 30 minutes until uniform.

[0057] S2. Then, sepiolite, mica flakes, and crack-resistant fibers are added to the horizontal zero-gravity mixer in sequence. The sepiolite and crack-resistant fibers need to be added slowly to ensure uniform dispersion. Stir and mix for 30 minutes until uniform.

[0058] S3. Add all of the 20-30 mesh and 30-50 mesh perlite into a horizontal zero-gravity mixer and mix for 3 minutes. Then process and package for use.

[0059] Performance Evaluation

[0060] I. Finished Product Performance Testing

[0061] The performance of the lightweight gypsum-based fire-retardant coating obtained in Example 1 was tested as follows. There were 4 groups of samples. The test results are detailed in Table 1.

[0062] Table 1

[0063]

[0064] II. Dry density properties

[0065] Dry density tests were conducted on the solid components in the raw materials. The test standard was based on the internal standard GB / T 14907-2018. The test results are detailed in Table 2. The manufacturers and models of the raw materials for each component are the same as in Example 1.

[0066] Table 2

[0067]

[0068] III. Bulk Density Properties

[0069] Dry density tests were conducted on the solid components in the raw materials. The test standard was based on the internal standard GB / T 14907-2018. The test results are detailed in Table 3. The manufacturers and models of the raw materials for each component are the same as in Example 1.

[0070] Table 3

[0071]

[0072]

[0073] IV. Adhesive properties

[0074] Adhesion performance tests were conducted on the following formulations, with the testing standards referring to the enterprise internal standard GB / T 14907-2018. The test results are detailed in Table 4; the manufacturers and models of the raw materials for each component are the same as in Example 1.

[0075] Table 4

[0076]

[0077]

Claims

1. A lightweight gypsum-based fire-retardant coating, characterized in that: The raw materials for preparing the lightweight gypsum-based fireproof coating include, by weight parts: 58-62 parts gypsum powder, 8-10 parts sepiolite, 4-6 parts mica flakes, 20-25 parts perlite, 0.1-0.5 parts thixotropic lubricant, 0.3-0.8 parts crack-resistant fiber, 0.8-1.2 parts binder, and 0.1-0.3 parts retarder; The gypsum powder mentioned includes hemihydrate gypsum; The perlite has a particle size of 20-30 mesh and 30-50 mesh, and the mass ratio of 20-30 mesh perlite to 30-50 mesh perlite is 9:

15. The mica sheets have a mesh size of 10-80 mesh; The length of the crack-resistant fiber is 6-25mm.

2. The lightweight gypsum-based fire-retardant coating according to claim 1, characterized in that: The raw materials for preparing the lightweight gypsum-based fireproof coating include, by weight, 60 parts gypsum powder, 9 parts sepiolite, 5 parts mica flakes, 24 parts perlite, 0.4 parts thixotropic lubricant, 0.5 parts crack-resistant fiber, 1 part adhesive, and 0.1 parts retarder.

3. A method for preparing a lightweight gypsum-based fire-retardant coating according to any one of claims 1-2, characterized in that: Includes the following steps: S1. Add the gypsum powder, adhesive, thixotropic lubricant, and retarder to a horizontal zero-gravity mixer according to the mass proportions, and stir and mix for no less than 15 minutes until uniform. S2. Then, sepiolite, mica flakes, and crack-resistant fibers are added to a horizontal zero-gravity mixer in sequence and mixed evenly for no less than 20 minutes until uniform. S3. Put the perlite into a horizontal zero-gravity mixer and stir for no more than 5 minutes. Then process and package it for use.

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