Gypsum material auxiliary, inorganic nano-gypsum composite material and preparation method

Abstract

To provide a gypsum material adjuvant which is used for gypsum foaming, improves freeze damage resistance of a gypsum material, and allows the gypsum material to satisfy the requirements for applications of a building wall, an internal and external heat insulating material, particularly an external wall, an inorganic nano-gypsum material containing the adjuvant, and a method for preparing the same.SOLUTION: The gypsum material auxiliary agent includes a first composition and a second composition, wherein the first composition includes polyethylene oxide, triethanolamine, aluminum potassium sulfate dodecahydrate, hydroxyethylidene diphosphate, sodium pyrophosphate, sodium molybdate, pentaerythritol, silicone amide, nanocellulose ether, anhydrous calcium chloride, dimethicone, and water, and the second composition includes hydrogen peroxide, polyanionic cellulose, polyethylene glycol, dimethylsiloxane, and water. In the present invention, the structure of the gypsum material is adjusted by the above-mentioned auxiliary materials for gypsum materials, and the stability of the foam structure is improved, thereby achieving good frost damage resistance.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention belongs to the technical field of building materials, and specifically relates to a gypsum material auxiliary, an inorganic nano-gypsum composite material and a preparation method. [Background technology]

[0002] The durability of building materials has become a hot topic in the engineering industry, especially in cold regions. Damage and deterioration caused by freeze-thaw cycles have a negative impact on the durability of the structure. Therefore, the "Autoclaved Aerated Concrete Blocks" (GB / T11968-2020) requires that the strength loss after 15 freeze-thaw cycles be less than 20%.

[0003] The development of lightweight, high-strength porous inorganic insulation materials made from gypsum (natural gypsum, solid waste gypsum) is highly promising. Currently, the manufacturing method and process for gypsum foam is simple, and it is common to add a foaming aid to gypsum, which reacts and expands to create foam. The introduced air bubbles increase the interface of the gypsum slurry phase, making the system prone to instability and directly affecting the performance of the gypsum foam. Freezing and thawing have a significant impact on the tensile and compressive strength of gypsum foam. As the number of freeze-thaw cycles increases, the degree of decay in tensile and compressive strength increases.

[0004] In light of this, the present invention aims to research a gypsum material auxiliary that can be used in gypsum foaming to improve the frost resistance of the structure, improve the frost resistance durability of the gypsum material, and enable the gypsum material to meet the requirements for use as a building wall, an interior or exterior thermal insulation material, especially an exterior wall. Summary of the Invention [Problem to be solved by the invention]

[0005] In consideration of the above technical challenges and deficiencies of the prior art, the present invention provides a gypsum foaming additive. The present invention adjusts the structure of the gypsum foam using the gypsum foaming additive, improving the stability of the foam structure and achieving good frost resistance. After 15 freeze-thaw cycles, the test specimens remained intact and maintained their compressive strength after freeze-thawing. The gypsum foaming additive can adjust the size, number, and thickness of the bubbles in the gypsum foam to meet the requirements of specific applications. The prepared gypsum foam has excellent mechanical properties, a compressive strength of up to 9 MPa, and relatively good thermal insulation, as well as fire, sound, and moisture protection. The process is simple and environmentally friendly. [Means for solving the problem]

[0006] An object of the present invention is to provide a gypsum material auxiliary agent comprising a first composition and a second composition, wherein the first composition comprises polyethylene oxide, triethanolamine, potassium aluminum sulfate dodecahydrate, hydroxyethylidene diphosphate, sodium pyrophosphate, sodium molybdate, pentaerythritol, silicone amide, nanocellulose ether, anhydrous calcium chloride, dimethicone, and water, and the second composition comprises hydrogen peroxide, polyanionic cellulose, polyethylene glycol, dimethylsiloxane, and water.

[0007] The polyethylene oxide and triethanolamine of the present invention are primarily used as foam film-forming agents to significantly improve the compressive strength of inorganic foamed gypsum materials. Triethanolamine stabilizes the foam structure, silicone amide creates a non-interconnected foam structure, and nanocellulose ether controls the number and size of the bubbles. Potassium aluminum sulfate dodecahydrate primarily enhances waterproofing and also increases compressive strength. Hydroxyethylidene diphosphate has a stable structure and is not easily hydrolyzed. Anhydrous calcium chloride maintains the acid-base balance of the inorganic foamed gypsum composite material, enhancing the density of the foam walls. The present invention adjusts the structure of the gypsum material with the gypsum material additives formulated in this way, improving the stability of the foam structure and achieving good frost resistance. Even after 15 freeze-thaw cycles, the test specimens remained intact and maintained their compressive strength after freeze-thawing.

[0008] In this invention, the number and size of bubbles are controlled by adjusting the amount of the first composition added, and the bubble thickness and overall strength are controlled by adjusting the amount of the second composition added, making it possible to control the number, size, and thickness of bubbles in the gypsum material and meet the specific requirements for gypsum materials in various application fields.The inorganic nano-gypsum material prepared in this invention has excellent mechanical properties and heat retention, with a compressive strength of up to 9 MPa and a low thermal conductivity of 0.02 W / m·K.

[0009] Furthermore, the first composition contains, as a component: 1 to 25 mass% of polyethylene oxide; 10 to 25 mass% of triethanolamine, 10 to 20 mass% of aluminum potassium sulfate dodecahydrate; 10 to 15% by mass of hydroxyethylidene diphosphate; 10 to 15% by mass of sodium pyrophosphate; 0.1 to 0.5 mass% of sodium molybdate, 5 to 10% by mass of pentaerythritol, 1 to 10 mass% of silicone amide; 5 to 10 mass% of nanocellulose ether; 1 to 5 mass% of anhydrous calcium chloride; 0.01 to 0.2% by mass of dimethicone, The remaining amount of water, The second composition comprises, as components: 10 to 50 mass% hydrogen peroxide, 10 to 25 mass% of polyanionic cellulose; 1 to 20 mass% of polyethylene glycol; 1 to 2 mass% of dimethylsiloxane; and the remaining amount of water.

[0010] Furthermore, the molecular weight of the polyethylene oxide is 50,000 to 150,000.

[0011] Furthermore, the molecular weight of nanocellulose ether is 0.5 to 20,000.

[0012] Another object of the present invention is to provide an inorganic nano-gypsum material, which includes gypsum powder, magnesium sulfate heptahydrate, a gypsum material auxiliary, and water.

[0013] Furthermore, the inorganic nano-gypsum material contains, as a component: 50 to 80 parts by mass of the gypsum powder, 1 to 25 parts by mass of the magnesium sulfate heptahydrate; 1 to 10 parts by mass of the first composition; 1 to 10 parts by mass of the second composition; and 1 to 50 parts by mass of the water.

[0014] The object of the present invention is also to (1) Preparation of the first composition A. Weigh out the ingredients in the appropriate ratio, add water to the reactor, add sodium molybdate, disperse and mix uniformly, add polyethylene oxide, and after all the polyethylene oxide is wet, disperse and mix uniformly. B. Add nanocellulose ether, triethanolamine, silicone amide, and pentaerythritol, disperse and mix evenly; C. adding aluminum potassium sulfate dodecahydrate, hydroxyethylidene diphosphate, sodium pyrophosphate, anhydrous calcium chloride, and dimethicone, dispersing and uniformly mixing to obtain a first composition; (2) Preparation of the second composition Weighing out each component in a mixing ratio, adding water to a reactor, adding hydrogen peroxide, polyanionic cellulose, polyethylene glycol, and dimethylsiloxane, and dispersing and mixing them uniformly to obtain a second composition; (3) Weighing gypsum powder, water, magnesium sulfate heptahydrate, the first composition, and the second composition in a mixing ratio; (4) dispersing and uniformly mixing the weighed amounts of water, magnesium sulfate heptahydrate, and the first composition; (5) adding gypsum powder and dispersing and mixing uniformly; (6) adding a second composition and dispersing and mixing uniformly to obtain an inorganic nanogypsum material.

[0015] In the present invention, the components of the first composition are first dispersed in a gypsum system and mixed uniformly, and then the second composition is added to the mixture of gypsum and the first composition. During the foaming process of the second composition, the first composition acts further on the bubbles to control the number and size of the bubbles and stabilize the bubble structure and function, and the second composition can also control the thickness and overall strength of the bubbles.

[0016] Furthermore, in the preparation of the first composition in step (1), the first dispersion stirring speed in step A is 1300 to 1600 r / min and the dispersion stirring time is 50 to 65 min, the second dispersion stirring speed in step B is 1300 to 1600 r / min and the dispersion stirring time is 15 to 45 min, and the third dispersion stirring speed in step C is 1300 to 1600 r / min and the dispersion stirring time is 15 to 45 min.

[0017] Furthermore, in the preparation of the second composition in step (2), the dispersion stirring speed is 600 to 1200 r / min, and the dispersion stirring time is 15 to 45 minutes.

[0018] Furthermore, in step (4), the dispersion stirring speed is 100 to 500 r / min and the dispersion stirring time is 0.1 to 10 min, in step (5), the dispersion stirring speed is 500 to 1500 r / min and the dispersion stirring time is 0.1 to 10 min, and in step (6), the mixture is dispersed and mixed uniformly, and the dispersion stirring time is 0.1 to 10 min. [Effects of the Invention]

[0019] The present invention has the following advantageous effects compared to the prior art.

[0020] (1) The present invention provides a gypsum material with a water barrier function by combining the first and second compositions, preventing a large number of water molecules from penetrating into the bubbles of the gypsum material. It also increases the thickness and density of the bubble walls, strengthening the bubbles and providing them with sealing properties, preventing the penetration of water molecules, and further improving the stability of the bubble structure. This prevents the bubbles from being compressed and deformed by the expansion and contraction forces generated by alternating cold and heat (-15°C to 105°C). This significantly improves the frost resistance of the gypsum material of the present invention. Even after 15 freeze-thaw cycles, the strength loss of the gypsum product is less than 20%, meeting the frost resistance requirements of the national standard "Autoclaved Aerated Concrete Blocks" (GB / T11968-2020). This allows the gypsum material to be used as building walls and interior and exterior insulation materials, particularly exterior walls.

[0021] (2) The present invention adjusts the number, size, and thickness of bubbles in gypsum foam using the first composition and the second composition, controlling the number and size of the bubbles by adjusting the amount of the first composition added, and the thickness and overall strength of the bubbles by adjusting the amount of the second composition added, thereby enabling flexible control of the pore density, size, and thickness of the gypsum material to meet the specific requirements for foam materials in various fields.

[0022] (3) The polyethylene oxide and triethanolamine used in this invention are primarily used as foam-forming materials, significantly improving the compressive strength of inorganic foamed gypsum materials. Polyanionic cellulose improves compressive strength by adjusting the number of bubbles depending on the amount added, while materials such as hydrogen peroxide adjust the thickness of the non-interconnected bubbles in inorganic gypsum composites. Magnesium sulfate heptahydrate not only has a foaming catalyst effect in inorganic gypsum composites, but also improves their hardness. The prepared foamed gypsum material is lightweight and high-strength, possessing relatively good mechanical strength, with a compressive strength of up to 9 MPa.

[0023] (4) Compared with conventional gypsum materials, the inorganic gypsum composite material prepared according to the present invention is lightweight, easy to apply, and can be used for heat insulation, with good heat retention and soundproofing effects. Its thermal conductivity is as low as 0.02 W / m·K, and soundproofing and noise reduction tests have reached 45 dB. It also has a certain degree of protection (shielding) against some low-frequency electromagnetic waves (such as power line radiation). Other protective materials (such as metals) can also be added to achieve high-frequency electromagnetic radiation shielding. Because gypsum is a porous material, it has very high water absorption and permeability. The material prepared according to the present invention has improved waterproofing and moisture resistance, reducing water absorption to 5%.

[0024] (5) The highly stable crystalline structure of the material of the present invention allows it to withstand temperatures up to 1700°C and absorb heat to provide fire protection. When a fire breaks out, the gypsum composite material absorbs thermal energy, lowering the surrounding temperature and slowing the spread of the fire, achieving a fire protection level of A1. Fire extinguishing function: The inorganic gypsum composite material is a non-combustible material with an A1 level. This product has thermal insulation and flame retardancy, and is a poor conductor of heat. In the event of a fire, less heat is transferred to the non-fired side, lowering its equilibrium temperature, preventing the non-fired side from rising to its ignition point and igniting other objects for a long period of time. Even when the non-fired side of the inorganic gypsum composite burns at high temperatures for 3.5 hours, the temperature of the non-fired side does not exceed 50°C, thus effectively demonstrating its fire protection and flame retardancy. The foamed gypsum product of this application has high temperature resistance, heat insulation, and fire prevention properties, and is non-ignitable, non-flammable, and non-carbonized, making it an A1-level fire-resistant material that can be widely used in various high-rise residential buildings and other civil buildings, as well as in the protective layers of exterior insulation systems. Furthermore, the foamed gypsum filler material made with this additive has the effects of corrosion resistance, high temperature resistance, ease of application, fire prevention, heat insulation, and sound insulation, and can improve the corrosion resistance of the material, allowing the gypsum product to maintain better stability at continuous high temperatures and extend its service life.

[0025] (6) Compared to organic high-temperature-resistant fillers, the gypsum of the present invention is extracted directly from nature or waste materials, making it a non-toxic, environmentally friendly inorganic raw material. The production and use of inorganic materials cause minimal environmental pollution, and the product uses water as a dispersion medium, posing no adverse impact on environmental protection or human health. In the event of a fire, the inorganic gypsum composite material releases only crystalline water and converts it into water vapor, eliminating the generation of toxic and suffocating combustion gases. It also eliminates the volatilization of decomposed substances, combustion-promoting substances, and smoke, thereby reducing the number of casualties in the event of a fire. The gypsum material of the present invention has the advantages of being environmentally friendly, natural, and non-toxic.

[0026] (7) The gypsum composite material of the present invention has waterproof and moisture-proof properties. Gypsum is a porous material with very high water absorption and permeability. Therefore, at room temperature, gypsum is not waterproof or moisture-proof. However, the gypsum composite material of the present invention has waterproof and moisture-proof properties, which further expands the range of applications of gypsum.

[0027] (8) The gypsum composite material of the present invention is recyclable. The present invention achieves higher compressive strength and excellent frost resistance by foaming gypsum using only inorganic raw materials. This process involves foaming gypsum without adding concrete or similar gel materials. Therefore, the present invention has excellent recyclability. Gypsum products produced by the present invention can be completely recycled and reused. [Brief explanation of the drawings]

[0028] [Figure 1] FIG. 1 is a comparison diagram of gypsum materials prepared in Example 1 of the present invention and Comparative Example 1. DETAILED DESCRIPTION OF THE INVENTION

[0029] The technical solutions of the present invention will be described clearly and completely below with reference to the embodiments of the present invention, but it is clear that the described embodiments are only a part of the embodiments of the present invention, and are not all of the embodiments. Based on the embodiments of the present invention, all other embodiments that a person skilled in the art can obtain without any creative efforts fall within the scope of protection of the present invention. [Example]

[0030] 1. Preparation of gypsum material auxiliary

[0031] 1. Preparation of the First Composition Step A: 38.7% by mass of water, 0.25% by mass of sodium molybdate, 2% by mass of polyethylene oxide (molecular weight 100,000), 5% by mass of nanocellulose ether (molecular weight 10,000), 15% by mass of triethanolamine, 5% by mass of pentaerythritol, 0.05% by mass of dimethicone, 2% by mass of anhydrous calcium chloride, 2% by mass of silicone amide, 10% by mass of sodium pyrophosphate, 10% by mass of hydroxyethylidene diphosphate, and 10% by mass of potassium aluminum sulfate dodecahydrate were weighed out.

[0032] First, a predetermined amount of water was added to the reactor, the reactor temperature was set to 70°C, the initial speed of the dispersing stirrer was set to 500 r / min, sodium molybdate was added, and the speed of the dispersing stirrer was set to 1500 r / min. Once the reaction temperature reached the set value of 70°C, the mixture was dispersed for 10 minutes. The reactor temperature was set to 25°C, and the speed of the dispersing stirrer was reduced to 500 r / min. After the polyethylene oxide was fully wetted, the dispersing stirrer speed (referred to as the first dispersing stirrer speed) was increased to 1500 r / min, and the dispersion time was set to 60 minutes.

[0033] Step B: Then, the speed of the dispersion agitator was set to 500 r / min, and nanocellulose ether, triethanolamine, silicone amide, and pentaerythritol were added in turn. The speed of the dispersion agitator (referred to as the second dispersion agitation speed) was increased to 1500 r / min, and the dispersion time was set to 30 minutes.

[0034] Step C: Finally, the disperser speed was set to 650 r / min, and potassium aluminum sulfate dodecahydrate, hydroxyethylidene diphosphate, sodium pyrophosphate, anhydrous calcium chloride, and dimethicone were added in that order, and the speed of the disperser agitator (referred to as the third disperser agitator speed) was increased to 1500 r / min, and the mixture was dispersed for 20 minutes. The reactor was then closed and cooled to room temperature to obtain a first composition.

[0035] Polyethylene oxide and triethanolamine are primarily used as foam-forming agents, significantly improving the compressive strength of inorganic foam gypsum materials and preventing powder shedding after solidification. Triethanolamine functions as a coating agent for application viscosity, pH adjustment, water reduction, and foam structure stabilization. Silicone amide and nanocellulose ether control the number and size of bubbles. Hydroxyethylidene diphosphate effectively inhibits the catalytic decomposition of hydrogen peroxide by metal ions. Sodium pyrophosphate primarily acts as a hydrogen peroxide stabilizer, improving the strength of inorganic gypsum composites. Pentaerythritol primarily functions as a surfactant, adhesive, and flame retardant. Sodium molybdate is used as a foam catalyst and corrosion inhibitor for metal materials, providing corrosion protection. Anhydrous calcium chloride maintains the acid-base balance of inorganic foam gypsum composites and enhances foam wall density. Dimethicone is primarily used for penetration and defoaming.

[0036] 2. Preparation of the Second Composition

[0037] 50% by mass of water, 10% by mass of polyanionic cellulose, 35% by mass of hydrogen peroxide, 3% by mass of polyethylene glycol, and 2% by mass of dimethylsiloxane were weighed out.

[0038] Water was added to the reaction vessel, the initial speed of the dispersion stirrer was set to 650 r / min, hydrogen peroxide, polyanionic cellulose, polyethylene glycol, and dimethylsiloxane were added, and then the speed of the dispersion stirrer was increased to 1000 r / min and the mixture was dispersed for 20 minutes. The reaction vessel was then closed to obtain the above-mentioned second composition.

[0039] The polyanionic cellulose in the second composition is thermally stable and salt-resistant, has strong antibacterial properties, and is resistant to mold and deterioration. Its amount also improves compressive strength by adjusting the number of bubbles. Materials such as hydrogen peroxide adjust the thickness of the non-interconnected bubbles in inorganic gypsum composites, adjusting compressive strength and meeting the specific requirements for gypsum materials in various application fields. Polyethylene glycol is a surfactant that provides inorganic foam gypsum composites with excellent lubrication, dispersibility, and adhesion. Dimethylsiloxane primarily reduces surface tension, aiding in lubrication and leveling.

[0040] 2. Preparation of gypsum composite material

[0041] 50 parts by mass of gypsum powder, 1.6 parts by mass of magnesium sulfate heptahydrate, 32 parts by mass of water, 1 part by mass of the first composition, and 1 part by mass of the second composition were weighed out.

[0042] The first composition and magnesium sulfate heptahydrate were added to the weighed water and mixed uniformly using a stirrer or disperser at a rotation speed of 180 r / min. After about 1 minute, gypsum powder was added and dispersed using a stirrer or disperser at a rotation speed of 1000 r / min. The gypsum powder and solution were thoroughly mixed. After 2 minutes, the second composition was added and dispersed for 1 minute. The mixture was then poured into a mold or packed into a product and cured to obtain an inorganic nano-foamed composite material. The gypsum composite material obtained by this blending had an expansion ratio of 2 times, and its density was measured to be 800.5 kg / m. 3 It has a thermal conductivity of 0.095W / m·K, soundproofing and noise reduction tests show a result of 31 to 45dB, and fire resistance tests show an A1 level of fire resistance. [Example]

[0043] 50 parts by mass of gypsum powder, 1.6 parts by mass of magnesium sulfate heptahydrate, 32 parts by mass of water, 1 part by mass of the first composition, and 2 parts by mass of the second composition were weighed out, and the preparation process was the same as in Example 1. The gypsum composite material obtained by this blending had an expansion ratio of 4 times, and when measured, its density was 650.6 kg / m 3 It has a thermal conductivity of 0.068W / m·K, soundproofing and noise reduction tests show a result of 31 to 45dB, and fire resistance tests show an A1 level of fire resistance. [Example]

[0044] 50 parts by mass of gypsum powder, 1.6 parts by mass of magnesium sulfate heptahydrate, 32 parts by mass of water, 2 parts by mass of the first composition, and 1 part by mass of the second composition were weighed out, and the preparation process was the same as in Example 1. The gypsum composite material obtained by this blending had an expansion ratio of 2.2 times, and when measured, its density was 750.8 kg / m 3 It has a thermal conductivity of 0.073W / m·K, soundproofing and noise reduction tests show a result of 31 to 45dB, and fire resistance tests show an A1 level of fire resistance. [Example]

[0045] 50 parts by mass of gypsum powder, 1.6 parts by mass of magnesium sulfate heptahydrate, 32 parts by mass of water, 3 parts by mass of the first composition, and 3 parts by mass of the second composition were weighed out, and the preparation process was the same as in Example 1. The gypsum composite material obtained by this blending had an expansion ratio of 4 times, and when measured, its density was 350.7 kg / m 3 It has a thermal conductivity of 0.051W / m·K, soundproofing and noise reduction tests show a result of 31 to 45dB, and fire resistance tests show an A1 level of fire resistance. [Example]

[0046] 50 parts by mass of gypsum powder, 1.6 parts by mass of magnesium sulfate heptahydrate, 32 parts by mass of water, 3 parts by mass of the first composition, and 6 parts by mass of the second composition were weighed out, and the preparation process was the same as in Example 1. The gypsum composite material obtained by this blending had an expansion ratio of 30 times, and when measured, its density was 80.2 kg / m 3 The thermal conductivity is 0.021 W / m K, the sound insulation and noise reduction test results are 31 to 45 dB, and the fire resistance test results are A1 level.

[0047] 100 parts by weight of gypsum hemihydrate, 50 parts by weight of anhydrous gypsum, 0.05 parts by weight of polycarboxylic acid water agent, 0.1 parts by weight of polyethylene oxide, 0.05 parts by weight of protein-based setting retarder for gypsum, and 0.06 parts by weight of starch ether were blended and mixed uniformly in a dry mixer. Next, 8 parts by weight of base acid, 0.5 parts by weight of hydroxybenzoate, and 300 parts by weight of water were mixed uniformly to obtain a foaming liquid. The foaming liquid was then placed in a foaming machine to foam and form bubbles. The foaming time was set at 4 minutes. Next, 100 parts by weight of water was added to the mixed dry powder material and stirred to obtain a mixed slurry. The mixed slurry was then mixed uniformly with the bubbles and placed in a mold to set. Measurements of the gypsum material prepared above revealed a density of 403.1 kg / m. 3 It was.

[0048] Performance Tests of Examples 1 to 5 and Comparative Example 1

[0049] 1.Comparison of internal structure The gypsum composite materials prepared above are shown in Figure 1. 1 is the gypsum composite material prepared in Example 1 of the present invention, and 2 is the gypsum material prepared in Comparative Example 1. As can be seen from the figure, the gypsum composite material prepared in Example 1 of the present invention is uniform and dense, with bubbles of relatively regular shape. Due to this stable bubble structure, the gypsum composite material prepared in the present invention has excellent frost resistance. The conventional gypsum material prepared in Comparative Example 1 has a more solid structure on the surface, but has almost no frost resistance.

[0050] 2. Freeze-thaw test Freeze-thaw test method (see the frost resistance test experiment in "Test methods for the performance of autoclaved aerated concrete" (GB / T11969-2020)) The freeze-thaw test involved immersing a freeze-thaw test specimen in a constant-temperature water bath at (20±2)°C for 48 hours. During the first 24 hours, the water level was half the height of the freeze-thaw test specimen, and during the final 24 hours, the water level was 30 mm higher than the freeze-thaw test specimen. The specimen was then removed, placed in a sealed plastic bag, and left for 24 hours. It was then placed in a cryogenic box pre-cooled to (-15±2)°C. The time when the temperature dropped back to -15°C was recorded, and the specimen was then removed after 8 hours or more. The removed freeze-thaw test specimen was then placed in a constant-temperature, constant-humidity bath at (20±2)°C and 95% relative humidity for 6 hours or more. An 8-hour period of freezing and a 6-hour period of thawing were considered one freeze-thaw cycle until the freeze-thaw test specimen had completed 15 freeze-thaw cycles. After the freeze-thaw process, the freeze-thaw test specimens were placed in an electric ventilation drying box and kept at (60±5)°C for 24 hours, then at (80±5)°C for 24 hours, and then baked at (105±5)°C until the mass was constant. After sealing and cooling to room temperature, the compressive strength of the test specimens was measured. The results of the freeze-thaw test are shown in the following table.

[0051] [Table 1]

[0052] The present invention employs a combination of the first and second compositions, which significantly improves frost resistance compared to Comparative Example 1 and allows the material to pass a 15-cycle freeze-thaw test. Comparative Example 1 softens immediately after the first freeze-thaw cycle. Furthermore, Examples 1 to 5 not only pass the 15-cycle freeze-thaw test, but also exhibit a strength reduction rate of less than 20%, meeting the frost resistance requirements of the national standard "Autoclaved Aerated Concrete Blocks" (GB / T11968-2020). This demonstrates that the gypsum material of the present invention has excellent frost resistance, while the gypsum material of Comparative Example 1, which does not use the first and second compositions of the present invention, has almost no frost resistance.

[0053] From the above Examples 1 to 5, it was found that adjusting the amounts of the first and second compositions added can produce gypsum products with similar performance. The strength, density, thermal conductivity, etc. of gypsum products prepared with different amounts of the first and second compositions differ, and these can be adjusted according to actual needs.

[0054] The ratio of the first and second compositions in Example 1 allows for thicker bubble walls. The ratio of the two compositions in Example 2 allows for larger bubbles. The ratio of the two compositions in Example 3 allows for greater overall bubble strength. The ratio of the two compositions in Example 4 allows for a greater number of bubbles. The ratio of the two compositions in Example 5 allows for an increased volume.

[0055] Therefore, by using the first composition and the second composition in combination, the present invention provides a gypsum material with a water barrier function, preventing a large number of water molecules from penetrating into the bubbles of the gypsum material. It also increases the thickness and density of the bubble walls, making the bubbles stronger and more airtight, preventing the penetration of water molecules, and further improving the stability of the bubble structure. This prevents the bubbles from being compressed and deformed by the expansion and contraction forces generated by alternating cold and heat (-15°C to 105°C). This significantly improves the frost resistance of the gypsum material of the present invention. Even after 15 freeze-thaw cycles, the strength loss of the gypsum product is less than 20%, meeting the frost resistance requirements of the national standard "Autoclaved Aerated Concrete Blocks" (GB / T11968-2020). This allows the gypsum material to be used as a building wall material, particularly for exterior walls.

[0056] The number, size, and thickness of the bubbles in the gypsum foam can be adjusted using the first composition and the second composition, and the number and size of the bubbles can be controlled by adjusting the amount of the first composition added, and the thickness and overall strength of the bubbles can be controlled by adjusting the amount of the second composition added.This makes it possible to flexibly control the pore density, size, and thickness of the gypsum material to meet the specific requirements for foam materials in various fields.

[0057] The above examples are for the purpose of illustrating the present invention, but are not intended to limit the present invention. Those skilled in the art may make various changes or modifications without departing from the spirit and scope of the present invention. Therefore, all equivalent technical solutions also belong to the scope of the present invention, which should be defined by the claims. [Explanation of symbols]

[0058] 1. Gypsum composite material prepared in Example 1 of the present invention 2 Gypsum material prepared in Comparative Example 1

Claims

1. A gypsum material auxiliary, The method includes the steps of: 1 to 25% by mass of polyethylene oxide; 10 to 25% by mass of triethanolamine; 10 to 20% by mass of aluminum potassium sulfate dodecahydrate; 10 to 15% by mass of hydroxyethylidene diphosphate; 10 to 15% by mass of sodium pyrophosphate; 0.1 to 0.5 mass% sodium molybdate; 5 to 10% by mass of pentaerythritol; 1 to 10% by mass of silicone amide; 5 to 10% by mass of nanocellulose ether; 1 to 5% by mass of anhydrous calcium chloride; 0.01 to 0.2% by mass of dimethicone; The remaining amount of water, The second composition comprises the following components: 10 to 50 mass% hydrogen peroxide, 10 to 25% by mass of polyanionic cellulose; 1 to 20% by mass of polyethylene glycol; 1 to 2% by mass of dimethylsiloxane; and the balance being water.

2. The gypsum material auxiliary according to claim 1, characterized in that the molecular weight of the polyethylene oxide is 50,000 to 150,000, and the molecular weight of the nanocellulose ether is 0.5 to 20,000.

3. 1. An inorganic nanogypsum material, comprising: An inorganic nano-gypsum material comprising gypsum powder, magnesium sulfate heptahydrate, the gypsum material auxiliary according to claim 1 or 2, and water.

4. As ingredients, 50 to 80 parts by mass of the gypsum powder; 1 to 25 parts by mass of the magnesium sulfate heptahydrate; 1 to 10 parts by mass of the first composition; 1 to 10 parts by weight of the second composition; The inorganic nanogypsum material according to claim 3, characterized in that it contains 1 to 50 parts by mass of water.

5. (1) Preparation of the first composition A. Weigh out the components in the appropriate ratio, add water to a reaction vessel, add sodium molybdate, disperse and mix uniformly, add polyethylene oxide, and after all the polyethylene oxide is wet, disperse and mix uniformly. B. Add nanocellulose ether, triethanolamine, silicone amide, and pentaerythritol and mix evenly to disperse; C. Adding aluminum potassium sulfate dodecahydrate, hydroxyethylidene diphosphate, sodium pyrophosphate, anhydrous calcium chloride, and dimethicone, dispersing and mixing uniformly to obtain a first composition; (2) Preparation of the second composition Weighing out each component in a mixing ratio, adding water to a reactor, adding hydrogen peroxide, polyanionic cellulose, polyethylene glycol, and dimethylsiloxane, and dispersing and mixing uniformly to obtain a second composition; (3) Weighing gypsum powder, water, magnesium sulfate heptahydrate, the first composition, and the second composition in a mixing ratio; (4) dispersing and uniformly mixing the weighed amounts of water, magnesium sulfate heptahydrate, and the first composition; (5) Add gypsum powder, disperse and mix evenly; (6) adding a second composition and dispersing and mixing uniformly to obtain the inorganic nanogypsum material.

6. In the preparation of the first composition in step (1), The first dispersion stirring speed in step A is 1300 to 1600 r / min, and the dispersion stirring time is 50 to 65 min, The second dispersion stirring speed in step B is 1300 to 1600 r / min, and the dispersion stirring time is 15 to 45 min; The method for preparing an inorganic nano-gypsum material according to claim 5, wherein the third dispersion stirring speed in step C is 1300-1600 r / min, and the dispersion stirring time is 15-45 min.

7. The method for preparing an inorganic nano-gypsum material according to claim 5, characterized in that in the preparation of the second composition in step (2), the dispersion stirring speed is 600 to 1200 r / min, and the dispersion stirring time is 15 to 45 min.

8. The method for preparing an inorganic nano-gypsum material according to claim 5, characterized in that in step (4), the dispersion stirring speed is 100 to 500 r / min and the dispersion stirring time is 0.1 to 10 min; in step (5), the dispersion stirring speed is 500 to 1500 r / min and the dispersion stirring time is 0.1 to 10 min; and in step (6), the dispersion is uniformly mixed and the dispersion stirring time is 0.1 to 10 min.

Images