Paper-faced gypsum board and method of making the same

Abstract

The application relates to a paper-faced gypsum board and a preparation method thereof. The paper-faced gypsum board comprises an A layer, a B layer and an A layer from top to bottom, the raw materials of the A layer comprise 100 parts by weight of desulfurized gypsum clinker, 50-75 parts by weight of water, 0.02-0.1 parts by weight of glass fiber, 0.1-2 parts by weight of a foaming agent, 0.05-0.5 parts by weight of a retarder, 0.2-2 parts by weight of starch and 0.01-0.5 parts by weight of a water reducing agent; the raw materials of the B layer comprise 100 parts by weight of desulfurized gypsum clinker, 60-80 parts by weight of water, 0.5-5 parts by weight of silica aerogel particles, 10-30 parts by weight of a reinforcing emulsion, 0.05-0.2 parts by weight of glass fiber, 0.2-1 parts by weight of a retarder and 0.2-1 parts by weight of starch. The silica aerogel particles are wrapped in the emulsion to prepare an intermediate gypsum slurry, and glass fiber and other components are added into the upper and lower gypsum slurries to ensure the strength of the gypsum board.

Description

Technical Field

[0001] This application belongs to the field of building materials, and specifically relates to paper-faced gypsum board and its preparation method. Background Technology

[0002] Against the backdrop of the nation's strong advocacy for energy-efficient buildings, developing the thermal insulation and energy-saving performance of indoor building materials is particularly important. In recent years, frequent fires in the building insulation and energy-saving sector have revealed the shortcomings of widely used organic insulation materials. Improving the fire resistance rating of building materials and promoting fire-resistant and heat-insulating materials with low thermal conductivity are inevitable development trends in the industry.

[0003] Silica aerogel is a Class A fire-resistant and heat-insulating material with excellent thermal insulation performance. Its thermal conductivity ranges from 0.013 W / (m·K) to 0.03 W / (m·K), far lower than that of inorganic insulation materials currently available in the market for building insulation and energy conservation. It possesses good thermal insulation and fire resistance, making it an ideal substitute for traditional insulation materials with promising application prospects. Paper-faced gypsum board has advantages such as being lightweight, fire-resistant, having good decorative properties, being easy to process, environmentally friendly, and space-saving. Therefore, it is widely used in various industrial and civil building decoration and construction fields, especially in high-rise buildings as an interior wall material and decorative material. Combining silica aerogel with gypsum board can create paper-faced gypsum board with even better thermal insulation performance, creating a safer and more comfortable indoor environment. However, silica aerogel particles are very light. When used in the preparation of paper-faced gypsum board, they tend to float and detach during the preparation of gypsum slurry, making it difficult to integrate into the gypsum slurry system. In addition, silica aerogel floats to the surface of the gypsum slurry, reaching the interface between the core and the facing paper, which seriously affects the bonding performance, resulting in a significant decrease in the strength of the board, even below the national standard, thus affecting its use. Summary of the Invention

[0004] To address the aforementioned issues, this application provides a paper-faced gypsum board and its preparation method. The paper-faced gypsum board provided in this application contains 20-200μm silica aerogel particles, significantly reducing the thermal conductivity of the paper-faced gypsum board and further improving its thermal insulation performance. Because silica aerogel particles are lightweight and easily float or detach during the preparation of the paper-faced gypsum board, making it difficult to integrate into the gypsum board slurry system, this application encapsulates the silica aerogel particles in an emulsion to prepare an intermediate layer of gypsum slurry. Glass fiber and other components are added to the upper and lower layers of gypsum slurry to ensure the strength of the gypsum board. Furthermore, the paper-faced gypsum board of this application has improved thermal insulation properties.

[0005] In one aspect, this application provides a paper-faced gypsum board, which comprises, from top to bottom, a layer A, a layer B, and a layer A, wherein the raw materials of layer A include the following components: 100 parts by weight of desulfurized gypsum clinker, 50-75 parts by weight of water, 0.02-0.1 parts by weight of glass fiber, 0.1-2 parts by weight of foaming agent, 0.05-0.5 parts by weight of retarder, 0.2-2 parts by weight of starch, and 0.01-0.5 parts by weight of water-reducing agent; the raw materials of layer B include the following components: 100 parts by weight of desulfurized gypsum clinker, 60-80 parts by weight of water, 0.5-5 parts by weight of silica aerogel particles, 10-30 parts by weight of reinforcing emulsion, 0.05-0.2 parts by weight of glass fiber, 0.2-1 parts by weight of retarder, and 0.2-1 parts by weight of starch.

[0006] In the embodiments of this application, the chloride ion content in the desulfurized gypsum clinker is no more than 300 ppm, and the specific surface area is 3500-4000 cm². 2 / g.

[0007] In the embodiments of this application, the glass fiber is any one of medium-alkali glass fiber, alkali-free glass fiber, and alkali-resistant glass fiber, with a fiber length of 9-15 mm and a single filament diameter of 10-15 μm.

[0008] In embodiments of this application, the foaming agent is selected from one or more inorganic foaming agents, such as ammonium dodecyl sulfate, sodium bicarbonate, and ammonium bicarbonate.

[0009] In the embodiments of this application, the retarder is citric acid, sodium citrate, sodium hexametaphosphate, or a protein-based retarder, preferably a bone collagen protein retarder.

[0010] In the embodiments of this application, the starch is a modified starch, which is selected from modified potato starch, modified cassava starch, modified sorghum starch or modified corn starch, preferably modified corn starch.

[0011] In the embodiments of this application, the water-reducing agent is a polycarboxylate water-reducing agent, preferably a powdered polycarboxylate water-reducing agent.

[0012] In embodiments of this application, the reinforcing emulsion is selected from one or more of polyvinyl acetate-ethylene emulsion, aqueous acrylic emulsion, styrene-acrylic emulsion, pure acrylic emulsion, silicone-acrylic emulsion, and polyurethane emulsion, preferably polyvinyl acetate-ethylene emulsion.

[0013] In the embodiments of this application, the particle size of the silica aerogel particles is 5-200 μm.

[0014] In an embodiment of this application, the paper-faced gypsum board comprises, from top to bottom, layer A, layer B, and layer A. The raw materials of layer A consist of the following components: 100 parts by weight of desulfurized gypsum clinker, 50-75 parts by weight of water, 0.02-0.1 parts by weight of glass fiber, 0.1-2 parts by weight of foaming agent, 0.05-0.5 parts by weight of retarder, 0.2-2 parts by weight of starch, and 0.01-0.5 parts by weight of water-reducing agent. The raw materials of layer B consist of the following components: 100 parts by weight of desulfurized gypsum clinker, 60-80 parts by weight of water, 0.5-5 parts by weight of silica aerogel particles, 10-30 parts by weight of reinforcing emulsion, 0.05-0.2 parts by weight of glass fiber, 0.2-1 parts by weight of retarder, and 0.2-1 parts by weight of starch.

[0015] On the other hand, this application provides a method for preparing the paper-faced gypsum board as described above, comprising the following steps:

[0016] Step 1: Weigh each component of the paper-faced gypsum board. The raw materials for layer A are: 100 parts by weight of desulfurized gypsum clinker, 50-75 parts by weight of water, 0.02-0.1 parts by weight of glass fiber, 0.1-2 parts by weight of foaming agent, 0.05-0.5 parts by weight of retarder, 0.2-2 parts by weight of starch, and 0.01-0.5 parts by weight of water-reducing agent. The raw materials for layer B are: 100 parts by weight of desulfurized gypsum clinker, 60-80 parts by weight of water, 0.5-5 parts by weight of silica aerogel particles, 10-30 parts by weight of reinforcing emulsion, 0.05-0.2 parts by weight of glass fiber, 0.2-1 parts by weight of retarder, and 0.2-1 parts by weight of starch.

[0017] Step 2: Mix the desulfurized gypsum clinker and glass fiber of layer A evenly. Add foaming agent, retarder, water-reducing agent, and starch to water and stir evenly. Mix the solid and liquid components and stir evenly to form layer A slurry. Mix the desulfurized gypsum clinker, glass fiber, retarder, starch, and silica aerogel particles of layer B evenly. Add reinforcing emulsion to water and stir evenly. Mix the solid and liquid components and continue stirring until the silica aerogel particles are coated with gypsum slurry to form layer B slurry.

[0018] Step 3: Pour gypsum slurry in layers on the bottom of the facing paper in sequence. The top and bottom layers are slurry A, and the middle layer is slurry B. That is, the paper-faced gypsum board is slurry A, slurry B and slurry A from top to bottom. It overlaps with the upper facing paper and is firmly bonded to form a wet board. Then the wet board is pulled out under the pull of the solidification belt to complete the molding.

[0019] Optionally, the B layer of mortar can account for one-half to two-thirds of the total volume of the gypsum board, and the A layer of mortar on the upper and lower sides can together account for one-third to one-half.

[0020] Step 4: The formed wet board is solidified on the conveyor belt, cut off, and then enters the dryer, where it goes through three drying stages: 160-180℃, 100-130℃, and 40-60℃.

[0021] Step 5: After drying, the boards are joined together, the edges are sawn, the edges are sealed, and the boards are packaged to form paper-faced gypsum board.

[0022] Compared with the prior art, this application has the following technical effects:

[0023] 1. The paper-faced gypsum board in this application contains silica aerogel particles of 5-200μm, which reduces the thermal conductivity of the paper-faced gypsum board and improves its thermal insulation performance.

[0024] 2. Silica aerogel particles are lightweight and easily float or detach during the preparation of paper-faced gypsum board, making it difficult to integrate into the gypsum board slurry system. Furthermore, they severely affect the adhesion between the core and the facing paper, reducing the board's mechanical properties. This application employs a layered gypsum slurry pouring method, encapsulating silica aerogel powder within the middle core layer of the gypsum board for fixation. This ensures that the adhesion between the upper and lower layers of gypsum slurry and the facing paper is not affected; moreover, the three layers of slurry are bonded together through glass fiber and gypsum crystals to form a unified whole.

[0025] Other features and advantages of this application will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the application. Other advantages of this application may be realized and obtained by means of the methods described in the description. Detailed Implementation

[0026] To make the objectives, technical solutions, and advantages of this application clearer, the embodiments of this application will be described in detail below. It should be noted that, unless otherwise specified, the embodiments and features described in these embodiments can be arbitrarily combined with each other.

[0027] This application provides a paper-faced gypsum board, which comprises, from top to bottom, layers A, B, and A. Layer A contains the following components: 100 parts by weight of desulfurized gypsum clinker, 50-75 parts by weight of water, 0.02-0.1 parts by weight of glass fiber, 0.1-2 parts by weight of foaming agent, 0.05-0.5 parts by weight of retarder, 0.2-2 parts by weight of starch, and 0.01-0.5 parts by weight of water-reducing agent. Layer B contains the following components: 100 parts by weight of desulfurized gypsum clinker, 60-80 parts by weight of water, 0.5-5 parts by weight of silica aerogel particles, 10-30 parts by weight of reinforcing emulsion, 0.05-0.2 parts by weight of glass fiber, 0.2-1 parts by weight of retarder, and 0.2-1 parts by weight of starch.

[0028] In the embodiments of this application, the chloride ion content in the desulfurized gypsum clinker is no more than 300 ppm, and the specific surface area is 3500-4000 cm². 2 / g.

[0029] In the embodiments of this application, the glass fiber is any one of medium alkali glass fiber, alkali-free glass fiber, and alkali-resistant glass fiber, with a fiber length of 9-15 mm and a single filament diameter of 10-15 μm.

[0030] In the embodiments of this application, the foaming agent is selected from one or more of the inorganic foaming agents ammonium dodecyl sulfate, sodium bicarbonate, and ammonium bicarbonate.

[0031] In the embodiments of this application, the retarder is citric acid, sodium citrate, sodium hexametaphosphate, or a protein-based retarder, preferably a bone collagen protein retarder.

[0032] In the embodiments of this application, the starch is modified starch, which is selected from modified potato starch, modified cassava starch, modified sorghum starch or modified corn starch, preferably modified corn starch.

[0033] In the embodiments of this application, the water-reducing agent is a polycarboxylate water-reducing agent, preferably a powdered polycarboxylate water-reducing agent.

[0034] In the embodiments of this application, the reinforcing emulsion is selected from one or more of polyvinyl acetate-ethylene emulsion, aqueous acrylic emulsion, styrene-acrylic emulsion, pure acrylic emulsion, silicone-acrylic emulsion and polyurethane emulsion, preferably polyvinyl acetate-ethylene emulsion.

[0035] In the embodiments of this application, the particle size of the silica aerogel particles is 5-200 μm.

[0036] In the embodiments of this application, the paper-faced gypsum board comprises, from top to bottom, layer A, layer B, and layer A. The raw materials of layer A are composed of the following components: 100 parts by weight of desulfurized gypsum clinker, 50-75 parts by weight of water, 0.02-0.1 parts by weight of glass fiber, 0.1-2 parts by weight of foaming agent, 0.05-0.5 parts by weight of retarder, 0.2-2 parts by weight of starch, and 0.01-0.5 parts by weight of water-reducing agent. The raw materials of layer B are composed of the following components: 100 parts by weight of desulfurized gypsum clinker, 60-80 parts by weight of water, 0.5-5 parts by weight of silica aerogel particles, 10-30 parts by weight of reinforcing emulsion, 0.05-0.2 parts by weight of glass fiber, 0.2-1 parts by weight of retarder, and 0.2-1 parts by weight of starch.

[0037] This application also provides a method for preparing the paper-faced gypsum board as described above, comprising the following steps:

[0038] Step 1: Weigh each component of the paper-faced gypsum board. The raw materials for layer A are: 100 parts by weight of desulfurized gypsum clinker, 50-75 parts by weight of water, 0.02-0.1 parts by weight of glass fiber, 0.1-2 parts by weight of foaming agent, 0.05-0.5 parts by weight of retarder, 0.2-2 parts by weight of starch, and 0.01-0.5 parts by weight of water-reducing agent. The raw materials for layer B are: 100 parts by weight of desulfurized gypsum clinker, 60-80 parts by weight of water, 0.5-5 parts by weight of silica aerogel particles, 10-30 parts by weight of reinforcing emulsion, 0.05-0.2 parts by weight of glass fiber, 0.2-1 parts by weight of retarder, and 0.2-1 parts by weight of starch.

[0039] Step 2: Mix the desulfurized gypsum clinker and glass fiber of layer A evenly. Add foaming agent, retarder, water-reducing agent, and starch to water and stir evenly. Mix the solid and liquid components and stir evenly to form layer A slurry. Mix the desulfurized gypsum clinker, glass fiber, retarder, starch, and silica aerogel particles of layer B evenly. Add reinforcing emulsion to water and stir evenly. Mix the solid and liquid components and continue stirring until the silica aerogel particles are coated with gypsum slurry to form layer B slurry.

[0040] Step 3: Pour gypsum slurry in layers on the bottom of the facing paper in sequence. The top and bottom layers are slurry A, and the middle layer is slurry B. That is, the paper-faced gypsum board is slurry A, slurry B and slurry A from top to bottom. It overlaps with the upper facing paper and is firmly bonded to form a wet board. Then the wet board is pulled out under the pull of the solidification belt to complete the molding.

[0041] Optionally, the B layer of mortar can account for one-half to two-thirds of the total volume of the gypsum board, and the A layer of mortar on the upper and lower sides can together account for one-third to one-half.

[0042] Step 4: The formed wet board solidifies on a conveyor belt, is cut, and then enters a dryer, undergoing three drying stages at 160-180℃, 100-130℃, and 40-60℃; and

[0043] Step 5: After drying, the boards are joined together, the edges are sawn, the edges are sealed, and the boards are packaged to form paper-faced gypsum board.

[0044] In the following examples and comparative examples, the desulfurized gypsum clinker used was made from desulfurized gypsum, a solid waste product generated from power plant flue gas desulfurization; glass fiber was purchased from Hebei Jinghang Mineral Products Co., Ltd.; foaming agent was purchased from Jinan Yihao Chemical Co., Ltd.; modified starch was purchased from Jinan Yuantong Chemical Co., Ltd.; the retarder was a bone glue protein retarder, purchased from Sichuan Sanwei Jinkang Materials Technology Co., Ltd.; polycarboxylate superplasticizer was purchased from Shandong Xinfuman Chemical Technology Co., Ltd.; emulsion was purchased from Beijing Kemite Technology Development Co., Ltd.; and silica aerogel particles were purchased from Keang Nanotechnology Co., Ltd.

[0045] Example 1

[0046] This embodiment provides a paper-faced gypsum board, which comprises, from top to bottom, layers A, B, and A. Layer A contains the following components: 100 parts by weight of desulfurized gypsum clinker, 58 parts by weight of water, 0.08 parts by weight of glass fiber, 0.4 parts by weight of sodium bicarbonate, 0.45 parts by weight of bone glue protein retarder, 0.3 parts by weight of modified corn starch, and 0.5 parts by weight of powdered polycarboxylate superplasticizer. Layer B contains the following components: 100 parts by weight of desulfurized gypsum clinker, 75 parts by weight of water, 4.5 parts by weight of silica aerogel particles, 30 parts by weight of polyvinyl acetate-ethylene emulsion, 0.2 parts by weight of glass fiber, 0.35 parts by weight of bone glue protein retarder, and 0.25 parts by weight of modified corn starch.

[0047] The preparation method of the paper-faced gypsum board in this embodiment is as follows:

[0048] Step 1: Weigh each component of the paper-faced gypsum board. The raw materials for layer A are: 100 parts by weight of desulfurized gypsum clinker, 58 parts by weight of water, 0.08 parts by weight of glass fiber, 0.4 parts by weight of sodium bicarbonate, 0.45 parts by weight of bone glue protein retarder, 0.3 parts by weight of modified corn starch, and 0.5 parts by weight of powdered polycarboxylate superplasticizer. The raw materials for layer B are: 100 parts by weight of desulfurized gypsum clinker, 75 parts by weight of water, 4.5 parts by weight of silica aerogel particles, 30 parts by weight of polyvinyl acetate-ethylene emulsion, 0.2 parts by weight of glass fiber, 0.35 parts by weight of bone glue protein retarder, and 0.25 parts by weight of modified corn starch.

[0049] Step 2: Mix the desulfurized gypsum clinker and glass fiber of layer A evenly; add foaming agent, retarder, water-reducing agent, and starch to water and stir evenly; mix the solid and liquid evenly to form layer A slurry; mix the desulfurized gypsum clinker, glass fiber, retarder, starch, and silica aerogel particles of layer B evenly; add reinforcing emulsion to water and stir evenly; mix the solid and liquid and continue stirring until the silica aerogel particles are coated with gypsum slurry to form layer B slurry;

[0050] Step 3: Pour gypsum slurry in layers on the bottom of the facing paper in sequence. The top and bottom layers are slurry A, and the middle layer is slurry B. That is, the paper-faced gypsum board is slurry A, slurry B and slurry A from top to bottom. It overlaps with the upper facing paper and is firmly bonded to form a wet board. Then the wet board is pulled out under the pull of the solidification belt to complete the molding.

[0051] In this embodiment, the B layer slurry accounts for half of the total volume of the gypsum board, and the A layer slurry accounts for half of the total volume of the gypsum board, with the top and bottom layers each accounting for one-quarter of the total volume.

[0052] Step 4: Allow the formed wet board to solidify on the conveyor belt, cut it, and then enter the dryer for three drying stages at 180℃, 110℃, and 45℃.

[0053] Step 5: After drying, the boards are joined together, the edges are sawn, the edges are sealed, and the boards are packaged to form paper-faced gypsum board.

[0054] Example 2

[0055] This embodiment provides a paper-faced gypsum board, which comprises, from top to bottom, layers A, B, and A. Layer A contains the following components: 100 parts by weight of desulfurized gypsum clinker, 70 parts by weight of water, 0.04 parts by weight of glass fiber, 2 parts by weight of sodium bicarbonate, 0.08 parts by weight of bone glue protein retarder, 1.8 parts by weight of modified corn starch, and 0.02 parts by weight of powdered polycarboxylate superplasticizer. Layer B contains the following components: 100 parts by weight of desulfurized gypsum clinker, 60 parts by weight of water, 1 part by weight of silica aerogel particles, 20 parts by weight of polyvinyl acetate-ethylene emulsion, 0.07 parts by weight of glass fiber, 0.7 parts by weight of bone glue protein retarder, and 0.8 parts by weight of modified corn starch.

[0056] Step 1: Weigh each component of the paper-faced gypsum board. The raw materials for layer A are: 100 parts by weight of desulfurized gypsum clinker, 70 parts by weight of water, 0.04 parts by weight of glass fiber, 2 parts by weight of sodium bicarbonate, 0.08 parts by weight of bone glue protein retarder, 1.8 parts by weight of modified corn starch, and 0.02 parts by weight of powdered polycarboxylate superplasticizer. The raw materials for layer B are: 100 parts by weight of desulfurized gypsum clinker, 60 parts by weight of water, 1 part by weight of silica aerogel particles, 20 parts by weight of polyvinyl acetate-ethylene emulsion, 0.07 parts by weight of glass fiber, 0.7 parts by weight of bone glue protein retarder, and 0.8 parts by weight of modified corn starch.

[0057] Step 2: Mix the components of layer A, desulfurized gypsum clinker and glass fiber, evenly; add foaming agent, retarder, water-reducing agent and starch to water, and stir evenly; mix the solid and liquid evenly to form layer A slurry; mix the components of layer B, desulfurized gypsum clinker, glass fiber, retarder, starch and silica aerogel particles, evenly; add reinforcing emulsion to water, and stir evenly; mix the solid and liquid, and continue stirring until the silica aerogel particles are coated with gypsum slurry to form layer B slurry.

[0058] Step 3: Pour gypsum slurry in layers on the bottom of the facing paper in sequence. The top and bottom layers are slurry A, and the middle layer is slurry B. That is, the paper-faced gypsum board is slurry A, slurry B and slurry A from top to bottom. It overlaps with the upper facing paper and is firmly bonded to form a wet board. Then the wet board is pulled out under the pull of the solidification belt to complete the molding.

[0059] In this embodiment, the B layer slurry accounts for two-thirds of the total volume of the gypsum board, the A layer slurry accounts for one-third of the total volume of the gypsum board, and the upper and lower layers each account for one-sixth.

[0060] Step 4: Allow the formed wet board to solidify on the conveyor belt, cut it off, and then enter the dryer for three drying stages at 170℃, 130℃, and 35℃.

[0061] Step 5: After drying, the boards are joined together, the edges are sawn, the edges are sealed, and the boards are packaged to form paper-faced gypsum board.

[0062] Example 3

[0063] This embodiment provides a paper-faced gypsum board, which comprises, from top to bottom, layers A, B, and A. Layer A contains the following components: 100 parts by weight of desulfurized gypsum clinker, 65 parts by weight of water, 0.03 parts by weight of glass fiber, 1 part by weight of sodium bicarbonate, 0.25 parts by weight of bone glue protein retarder, 1.0 part by weight of modified corn starch, and 0.3 parts by weight of powdered polycarboxylate superplasticizer. Layer B contains the following components: 100 parts by weight of desulfurized gypsum clinker, 60 parts by weight of water, 3 parts by weight of silica aerogel particles, 10 parts by weight of polyvinyl acetate-ethylene emulsion, 1.8 parts by weight of glass fiber, 1 part by weight of bone glue protein retarder, and 0.6 parts by weight of modified corn starch.

[0064] Step 1: Weigh each component of the paper-faced gypsum board. The raw materials for layer A are: 100 parts by weight of desulfurized gypsum clinker, 65 parts by weight of water, 0.03 parts by weight of glass fiber, 1 part by weight of sodium bicarbonate, 0.25 parts by weight of bone glue protein retarder, 1.0 part by weight of modified corn starch, and 0.3 parts by weight of powdered polycarboxylate superplasticizer. The raw materials for layer B are: 100 parts by weight of desulfurized gypsum clinker, 60 parts by weight of water, 3 parts by weight of silica aerogel particles, 10 parts by weight of polyvinyl acetate-ethylene emulsion, 1.8 parts by weight of glass fiber, 1 part by weight of bone glue protein retarder, and 0.6 parts by weight of modified corn starch.

[0065] Step 2: Mix the components of layer A, desulfurized gypsum clinker and glass fiber, evenly; add foaming agent, retarder, water-reducing agent and starch to water, and stir evenly; mix the solid and liquid evenly to form layer A slurry; mix the components of layer B, desulfurized gypsum clinker, glass fiber, retarder, starch and silica aerogel particles, evenly; add reinforcing emulsion to water, and stir evenly; mix the solid and liquid, and continue stirring until the silica aerogel particles are coated with gypsum slurry to form layer B slurry.

[0066] Step 3: Pour gypsum slurry in layers on the bottom of the facing paper in sequence. The top and bottom layers are slurry A, and the middle layer is slurry B. That is, the paper-faced gypsum board is slurry A, slurry B and slurry A from top to bottom. It overlaps with the upper facing paper and is firmly bonded to form a wet board. Then the wet board is pulled out under the pull of the solidification belt to complete the molding.

[0067] In this embodiment, the B layer slurry accounts for two-thirds of the total volume of the gypsum board, the A layer slurry accounts for one-third of the total volume of the gypsum board, and the upper and lower layers each account for one-sixth.

[0068] Step 4: Allow the formed wet board to solidify on the conveyor belt, cut it off, and then enter the dryer for three drying stages at 160℃, 105℃, and 55℃.

[0069] Step 5: After drying, the boards are joined together, the edges are sawn, the edges are sealed, and the boards are packaged to form paper-faced gypsum board.

[0070] Comparative Example 1

[0071] The paper-faced gypsum board of Comparative Example 1 was prepared using only the B component formulation of Example 1, combined with conventional preparation processes.

[0072] The preparation method of the paper-faced gypsum board in Comparative Example 1 is as follows:

[0073] Step 1: Weigh the components of the paper-faced gypsum board: 100 parts by weight of desulfurized gypsum clinker, 75 parts by weight of water, 4.5 parts by weight of silica aerogel particles, 30 parts by weight of reinforcing emulsion, 0.2 parts by weight of glass fiber, 0.35 parts by weight of retarder, and 0.25 parts by weight of starch.

[0074] Step 2: Mix the desulfurized gypsum clinker, glass fiber, retarder, starch, and silica aerogel particles evenly; add reinforcing emulsion to water and stir evenly; mix the solid and liquid, and continue stirring until the silica aerogel particles are coated with gypsum slurry to form a slurry; at this point, some silica aerogel particles cannot be completely coated by the gypsum slurry and float on the surface of the slurry.

[0075] Step 3: Before the slurry initially sets, it is thrown onto the lower protective paper on the forming table under the action of centrifugal force. Under the traction of the coagulation belt, it is squeezed by the forming knife, so that the lower protective paper is folded at a right angle along the roller mark. The lower protective paper and the slurry overlap with the upper protective paper under the pressure of the forming plate and stick together to form a wet board. Then the wet board is pulled out under the traction of the coagulation belt to complete the forming.

[0076] Step 4: Allow the wet board to solidify on the conveyor belt, cut it off, and then enter the dryer for three drying stages at 180℃, 110℃, and 45℃.

[0077] Step 5: After drying, the boards are joined together, the edges are sawn, the edges are sealed, and the boards are packaged to form paper-faced gypsum board.

[0078] Comparative Example 2

[0079] Commercially available ordinary paper-faced gypsum board.

[0080] Test Example 1

[0081] The paper-faced gypsum boards of Examples 1-3 and Comparative Examples 1-2 were tested in accordance with the Chinese national standard GB / T9775-2008 "Paper-faced Gypsum Board" to detect their physical and mechanical properties. The results are shown in Table 1.

[0082] Table 1 Performance test results of paper-faced gypsum board

[0083]

[0084] As shown in Table 1, the paper-faced gypsum boards prepared in Examples 1-3 of this application meet the national standard requirements in terms of mechanical properties, and the thermal conductivity is significantly reduced. Examples 1-3 overcome the problems of silica aerogel dust flying and uneven dispersion, or poor adhesion of paper-faced gypsum boards, and improve the strength of paper-faced gypsum boards, which is slightly higher than that of commercially available ordinary paper-faced gypsum boards in Comparative Example 2. Comparative Example 1 changed the process and only used the silica aerogel-containing layer component in Example 1 to prepare paper-faced gypsum boards. As a result, the silica aerogel particles affected the adhesion performance of the paper-faced gypsum boards, thereby reducing the mechanical properties. This is because during the preparation of gypsum slurry, some silica aerogel particles cannot be completely coated by the gypsum slurry and float on the surface of the slurry. After overlapping with the upper and lower layers of facing paper, they remain on the base surface between the facing paper and the gypsum core layer, resulting in poor adhesion of the board and a decrease in mechanical properties.

[0085] Although the embodiments disclosed in this application are as described above, the content described is merely for the purpose of understanding this application and is not intended to limit this application. Any person skilled in the art to which this application pertains may make any modifications and changes in the form and details of the implementation without departing from the spirit and scope disclosed in this application; however, the scope of patent protection of this application shall still be determined by the scope defined in the appended claims.

Claims

1. A paper-faced gypsum board, comprising, from top to bottom, layers A, B, and layer A, wherein the raw materials of layer A include the following components: 100 parts by weight of desulfurized gypsum clinker, 50-75 parts by weight of water, 0.02-0.1 parts by weight of glass fiber, 0.1-2 parts by weight of foaming agent, 0.05-0.5 parts by weight of retarder, 0.2-2 parts by weight of starch, and 0.01-0.5 parts by weight of water-reducing agent; the raw materials of layer B include the following components: 100 parts by weight of desulfurized gypsum clinker, 60-80 parts by weight of water, 0.5-5 parts by weight of silica aerogel particles, 10-30 parts by weight of reinforcing emulsion, 0.05-0.2 parts by weight of glass fiber, 0.2-1 parts by weight of retarder, and 0.2-1 parts by weight of starch.

2. The paper-faced gypsum board according to claim 1, wherein, The chloride ion content in the desulfurized gypsum clinker is no more than 300 ppm, and the specific surface area is 3500-4000 cm². 2 / g.

3. The paper-faced gypsum board according to any one of claims 1-2, wherein, The glass fiber is any one of medium-alkali glass fiber, alkali-free glass fiber, and alkali-resistant glass fiber, with a fiber length of 9-15 mm and a single filament diameter of 10-15 μm.

4. The paper-faced gypsum board according to any one of claims 1-2, wherein, The foaming agent is selected from one or more inorganic foaming agents, namely ammonium dodecyl sulfate, sodium bicarbonate, and ammonium bicarbonate.

5. The paper-faced gypsum board according to any one of claims 1-2, wherein, The retarder is citric acid, sodium citrate, sodium hexametaphosphate, or a protein-based retarder.

6. The paper-faced gypsum board according to claim 5, wherein, The retarder is a bone collagen protein retarder.

7. The paper-faced gypsum board according to any one of claims 1-2, wherein, The starch is a modified starch, which is selected from modified potato starch, modified cassava starch, modified sorghum starch or modified corn starch.

8. The paper-faced gypsum board according to claim 7, wherein, The modified starch is modified corn starch.

9. The paper-faced gypsum board according to any one of claims 1-2, wherein, The water-reducing agent is a polycarboxylate water-reducing agent.

10. The paper-faced gypsum board according to claim 9, wherein, The water-reducing agent is a powdered polycarboxylate water-reducing agent.

11. The paper-faced gypsum board according to any one of claims 1-2, wherein, The reinforcing emulsion is selected from one or more of polyvinyl acetate-ethylene emulsion, aqueous acrylic emulsion, and polyurethane emulsion.

12. The paper-faced gypsum board according to claim 11, wherein, The aqueous acrylic emulsion is selected from one or more of styrene-acrylic emulsion, pure acrylic emulsion, and silicone-acrylic emulsion.

13. The paper-faced gypsum board according to claim 11, wherein, The reinforcing agent is a polyvinyl acetate-ethylene emulsion.

14. The paper-faced gypsum board according to any one of claims 1-2, wherein, The particle size of the silica aerogel particles is 5-200 μm.

15. A method for preparing paper-faced gypsum board according to any one of claims 1-9, comprising the following steps: Step 1: Weigh each component of the paper-faced gypsum board. The raw materials for layer A are: 100 parts by weight of desulfurized gypsum clinker, 50-75 parts by weight of water, 0.02-0.1 parts by weight of glass fiber, 0.1-2 parts by weight of foaming agent, 0.05-0.5 parts by weight of retarder, 0.2-2 parts by weight of starch, and 0.01-0.5 parts by weight of water-reducing agent. The raw materials for layer B are: 100 parts by weight of desulfurized gypsum clinker, 60-80 parts by weight of water, 0.5-5 parts by weight of silica aerogel particles, 10-30 parts by weight of reinforcing emulsion, 0.05-0.2 parts by weight of glass fiber, 0.2-1 parts by weight of retarder, and 0.2-1 parts by weight of starch. Step 2: Mix the desulfurized gypsum clinker and glass fiber of layer A evenly. Add foaming agent, retarder, water-reducing agent, and starch to water and stir evenly. Mix the solid and liquid components and stir evenly to form layer A slurry. Mix the desulfurized gypsum clinker, glass fiber, retarder, starch, and silica aerogel particles of layer B evenly. Add reinforcing emulsion to water and stir evenly. Mix the solid and liquid components and continue stirring until the silica aerogel particles are coated with gypsum slurry to form layer B slurry. Step 3: Pour gypsum slurry in layers on the bottom of the facing paper in sequence. The top and bottom layers are slurry A, and the middle layer is slurry B. That is, the paper-faced gypsum board is slurry A, slurry B and slurry A from top to bottom. It overlaps with the upper facing paper and is firmly bonded to form a wet board. Then the wet board is pulled out under the pull of the solidification belt to complete the molding. Step 4: The formed wet board is solidified on the conveyor belt, cut off, and then enters the dryer, where it goes through three drying stages: 160-180℃, 100-130℃, and 40-60℃. Step 5: After drying, the boards are joined together, the edges are sawn, the edges are sealed, and the boards are packaged to form paper-faced gypsum board.

16. The method according to claim 15, wherein, In step two, layer B slurry accounts for one-half to two-thirds of the total volume of the gypsum board, while layer A slurry on the top and bottom sides accounts for one-third to one-half of the total volume.

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