An ultra-lightweight inorganic high-efficiency thermal insulation material and a preparation method thereof

Abstract

The application discloses a kind of super-light inorganic high-efficiency thermal insulation materials and preparation method thereof.The super-light inorganic high-efficiency thermal insulation material of the application is mainly prepared by the following components by pressure foaming-decompression foaming process according to weight parts: light-burned magnesium oxide 28-37 parts, magnesium sulfate heptahydrate 18-26 parts, compound foaming agent 0.8-1.5 parts, compound foam stabilizer 0.08-0.12 parts, water reducing agent 0.1-0.3 parts, and water 45-58 parts.The application prepares inorganic high-efficiency thermal insulation material by pressure foaming-decompression foaming process.Under pressure conditions, a large number of stable and uniform bubbles are introduced into the inorganic thermal insulation material, then a large number of uniform and stable pressurized bubbles are mixed uniformly with cement slurry to obtain foamed slurry.In the process of pressure relief, the bubbles inside the pressurized foamed slurry expand uniformly, achieving super-light design.The bulk density of the prepared super-light inorganic high-efficiency thermal insulation material can reach 41-60 kg / m 3 , the strength is greater than or equal to 10 kPa, and the thermal conductivity can reach 0.029-0.035 W / (m·k).

Description

Technical Field

[0001] This invention relates to the field of building insulation materials technology, specifically to an ultralight inorganic high-efficiency insulation material and its preparation method. Background Technology

[0002] Thermal insulation materials are a crucial material foundation for achieving building energy conservation. While new high-efficiency insulation materials such as aerogel and vacuum insulation panels have extremely low thermal conductivity, they suffer from key issues such as high cost, complex construction, and easy performance degradation. Organic materials like expanded polystyrene offer good insulation, are inexpensive, and easy to install, making them widely used; however, they are flammable and difficult to meet Class A non-combustible standards, posing a fire hazard.

[0003] Cement-based insulation materials have advantages such as low cost and non-combustibility, with a thermal conductivity of 0.08-0.22 W / m·K, significantly higher than that of organic insulation materials (0.025-0.042 W / m·K). Therefore, developing new inorganic high-efficiency insulation materials that balance ultra-low thermal conductivity with Class A fire safety, meeting building energy conservation requirements while improving building fire safety, is of great significance. Summary of the Invention

[0004] In view of this, the present invention aims to provide an ultra-lightweight inorganic high-efficiency thermal insulation material, which is made from lightly calcined magnesium oxide, magnesium sulfate heptahydrate, and water as the main raw materials, and is produced by a pressing-depressurization foaming process under the action of water-reducing agent, compound foaming agent and compound foam stabilizer. This effectively solves the problem that existing inorganic materials are fireproof but have insufficient thermal insulation performance, and organic materials have excellent thermal insulation performance but are not fireproof.

[0005] To achieve the above objectives, the technical solution of the present invention is implemented as follows:

[0006] An ultralight inorganic high-efficiency thermal insulation material, by weight, is mainly composed of the following components obtained through a pressing-depressurization foaming process: 28-37 parts of lightly calcined magnesium oxide, 18-26 parts of magnesium sulfate heptahydrate, 0.8-1.5 parts of compound foaming agent, 0.08-0.12 parts of compound foam stabilizer, 0.1-0.3 parts of water-reducing agent, and 45-58 parts of water.

[0007] Optionally, the lightly calcined magnesium oxide has an MgO content of ≥80% and an average particle size of 13.86μm-16.32μm.

[0008] Optionally, the magnesium sulfate heptahydrate has a MgSO4 content of ≥45%.

[0009] Optionally, the compound foaming agent is a mixture of sodium dodecyl sulfate and sodium α-alkenyl sulfonate; the mass ratio of sodium dodecyl sulfate to sodium α-alkenyl sulfonate is (1.8-2.3):(2.9-3.6).

[0010] Optionally, the compound foam stabilizer is a mixture of water-soluble silicone oil and castor oil polyoxyethylene ether; the mass ratio of the water-soluble silicone oil to the castor oil polyoxyethylene ether is (3.7-4.2):(2.6-3.1), wherein the water-soluble silicone oil is preferably DC-193.

[0011] Optionally, the water-reducing agent is a polycarboxylate water-reducing agent with a solid content of 35%-45% and a water reduction rate of 26-30%.

[0012] The second objective of this invention is to provide a method for preparing the above-mentioned ultralight inorganic high-efficiency thermal insulation material, the method comprising the following steps:

[0013] 1) Dissolve the compound foaming agent and the compound foam stabilizer in water at 10% of the total water volume, place them in pressure tank A, and stir under pressure to produce uniform and fine pre-made foam.

[0014] 2) Dissolve the magnesium sulfate heptahydrate in water accounting for 80% of the total water volume to prepare a magnesium sulfate solution;

[0015] 3) The lightly calcined magnesium oxide, the magnesium sulfate solution, the water-reducing agent and water accounting for 10% of the total water volume are mixed and placed in pressure tank B with the same pressure as pressure tank A and stirred to make them evenly mixed to obtain magnesium sulfate-magnesium cement slurry.

[0016] 4) Mix the pre-made foam in pressure tank A with the magnesium oxysulfate cement slurry in pressure tank B. Keep the pressure in pressure tank B constant during the mixing process. After the mixture is evenly mixed, open the pressure relief valve of pressure tank B to allow the foamed slurry to expand under normal pressure, thereby obtaining an ultra-lightweight inorganic high-efficiency thermal insulation material.

[0017] Optionally, the pressure of the pressure tank A in step 1) is 0.3-0.8 MPa, the stirring rate of the pressurized agitator is 400-600 rpm / min, and the stirring time is 30-60 s.

[0018] Optionally, the stirring time in step 3) is 100-150s.

[0019] Preparation mechanism of the present invention:

[0020] This invention prepares inorganic high-efficiency thermal insulation materials through a pressurized foaming-depressurization foaming process. Under pressurized conditions, a large number of stable and uniform air bubbles are introduced into the inorganic thermal insulation material. Then, the large number of uniform and stable pressurized air bubbles are mixed evenly with cement slurry to obtain a foamed slurry. During the depressurization process, the air bubbles inside the pressurized foamed slurry expand uniformly, achieving an ultra-lightweight design.

[0021] Compared with existing technologies, the ultralight inorganic high-efficiency thermal insulation material of the present invention has the following advantages:

[0022] 1. The pressurized foaming-depressurization foaming process provided by this invention introduces air bubbles into inorganic thermal insulation materials, stabilizes the bubbles, controls the uniformity of the bubbles, and utilizes the uniform expansion of the gas inside the bubbles during the depressurization process to achieve an ultra-lightweight design. The resulting ultra-lightweight inorganic high-efficiency thermal insulation material can achieve a bulk density of 41-60 kg / m³. 3 It has a strength ≥10kPa and a thermal conductivity of 0.029-0.035W / (m·k).

[0023] 2. This invention utilizes a pressurized foaming-depressurization foaming process. When pressurization is applied to the pressure tank, the external pressure increases, continuously squeezing the liquid bubbles to make them into foams of uniform size. This improves the pore structure and achieves consistency between the solidification and hardening of inorganic thermal insulation materials and the formation of the pore structure. It solves the problems of insufficient gas generation or pore structure defects that exist in the technology of preparing inorganic thermal insulation materials by foaming process. Detailed Implementation

[0024] To enable those skilled in the art to better understand the technical solutions and effects of the present invention, several embodiments will be provided below. Obviously, the following description is only an embodiment and does not limit the scope of protection of the present invention.

[0025] Table 1 shows the proportions and performance parameters of each component in the ultra-lightweight inorganic high-efficiency thermal insulation materials of Examples 1-6 of the present invention. Among them, the water-reducing agent is a polycarboxylate water-reducing agent with a solid content of 35% and a water reduction rate of 28%.

[0026] Table 1 Material Proportioning Design

[0027]

[0028] The ultralight inorganic high-efficiency thermal insulation materials of Examples 1-6 were prepared using the following method, specifically including the following steps:

[0029] 1) Weigh each raw material according to the material ratio in Table 1, and control the error to be accurate to ±0.01g;

[0030] 2) Dissolve the compound foaming agent and compound foam stabilizer in 10% of the total water volume and place them in pressure tank A. Stir under pressure to produce uniform and fine pre-made foam. The pressure applied is shown in Table 1. The stirring rate can be controlled at 500 rpm / min and the stirring time can be controlled at 45 s.

[0031] 2) Dissolve magnesium sulfate heptahydrate in water that accounts for 80% of the total water volume to prepare a magnesium sulfate solution;

[0032] 3) Mix lightly calcined magnesium oxide, magnesium sulfate solution, water-reducing agent and water accounting for 10% of the total water volume, and place them in pressure tank B with the same pressure as pressure tank A. Stir for 120 seconds to make them evenly mixed to obtain magnesium sulfate-magnesium cement paste.

[0033] 4) Mix the pre-made foam in pressure tank A with the magnesium oxysulfate cement slurry in pressure tank B. Keep the pressure of pressure tank B constant during the mixing process. After the mixture is evenly mixed, open the pressure relief valve of pressure tank B to allow the foamed slurry to expand under normal pressure, thus obtaining an ultra-lightweight inorganic high-efficiency thermal insulation material.

[0034] The performance of the ultralight inorganic high-efficiency thermal insulation materials of Examples 1-6 of this invention is shown in Table 2.

[0035] Table 2 Implementation Performance Evaluation

[0036] Example <![CDATA[Unit weight (kg / m 3 )]]> Strength (kPa) Thermal conductivity (W / (m·K)) 1 60 14 0.035 2 58 14 0.035 3 52 13 0.033 4 49 12 0.032 5 45 11 0.031 6 41 10 0.031

[0037] As can be seen from the performance evaluation data in Table 2, the bulk density of the ultralight inorganic high-efficiency thermal insulation material prepared in the embodiments of the present invention can reach 41-60 kg / m³. 3 The strength is ≥10kPa, and the thermal conductivity can reach 0.029-0.035W / (m·k). As the pressure applied inside the pressure tank increases, the density and thermal conductivity of the ultra-lightweight inorganic high-efficiency thermal insulation material prepared in this embodiment of the invention decrease, while the strength still meets the design target. Among them, compared with Example 1, the density of Example 6 is reduced by 31.7%, and the thermal conductivity is reduced by 11.4%.

[0038] The above are merely preferred embodiments of the present invention and are not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A lightweight inorganic high-efficiency thermal insulation material, characterized in that, It is mainly produced by the following components through a pressure-decompression foaming process: by weight, 28-37 parts of lightly calcined magnesium oxide, 18-26 parts of magnesium sulfate heptahydrate, 0.8-1.5 parts of compound foaming agent, 0.08-0.12 parts of compound foam stabilizer, 0.1-0.3 parts of water-reducing agent, and 45-58 parts of water; The compound foaming agent is a mixture of sodium dodecyl sulfate and sodium α-alkenyl sulfonate; the mass ratio of sodium dodecyl sulfate to sodium α-alkenyl sulfonate is (1.8-2.3):(2.9-3.6); The compound foam stabilizer is a mixture of water-soluble silicone oil and castor oil polyoxyethylene ether; the mass ratio of the water-soluble silicone oil to the castor oil polyoxyethylene ether is (3.7-4.2):(2.6-3.1); The ultralight inorganic high-efficiency thermal insulation material is prepared by the following method: 1) Dissolve the compound foaming agent and compound foam stabilizer in 10% of the total water volume in pressure tank A, stir under pressure to prepare uniform and fine pre-made foam. The pressure is 0.3-0.8 MPa, the stirring speed is 400-600 rpm, and the stirring time is 30-60 s. 2) Dissolve magnesium sulfate heptahydrate in water that accounts for 80% of the total water volume to prepare a magnesium sulfate solution; 3) Mix lightly calcined magnesium oxide, magnesium sulfate solution, water-reducing agent and water accounting for 10% of the total water volume, and then place them in pressure tank B with the same pressure as pressure tank A and stir to make them evenly mixed to obtain magnesium sulfate-magnesium cement paste. 4) Mix the pre-made foam in pressure tank A with the magnesium oxysulfate cement slurry in pressure tank B. Keep the pressure in pressure tank B constant during the mixing process. After the mixture is evenly mixed, open the pressure relief valve of pressure tank B to allow the foamed slurry to expand under normal pressure, thereby obtaining an ultra-lightweight inorganic high-efficiency thermal insulation material.

2. The ultralight inorganic high-efficiency thermal insulation material according to claim 1, characterized in that, The lightly calcined magnesium oxide has an MgO content of ≥80% and an average particle size of 13.86 μm-16.32 μm.

3. The ultralight inorganic high-efficiency thermal insulation material according to claim 1, characterized in that, The magnesium sulfate heptahydrate has a MgSO4 content of ≥45%.

4. The ultralight inorganic high-efficiency thermal insulation material according to claim 1, characterized in that, The water-reducing agent is a polycarboxylate water-reducing agent with a solid content of 35%-45% and a water reduction rate of 26-30%.

5. A method for preparing the ultralight inorganic high-efficiency thermal insulation material according to any one of claims 1-4, characterized in that, Includes the following steps: 1) Dissolve the compound foaming agent and compound foam stabilizer in 10% of the total water volume in pressure tank A, stir under pressure to prepare uniform and fine pre-made foam. The pressure is 0.3-0.8 MPa, the stirring speed is 400-600 rpm, and the stirring time is 30-60 s. 2) Dissolve magnesium sulfate heptahydrate in water that accounts for 80% of the total water volume to prepare a magnesium sulfate solution; 3) Mix lightly calcined magnesium oxide, magnesium sulfate solution, water-reducing agent and water accounting for 10% of the total water volume, and then place them in pressure tank B with the same pressure as pressure tank A and stir to make them evenly mixed to obtain magnesium sulfate-magnesium cement paste. 4) Mix the pre-made foam in pressure tank A with the magnesium oxysulfate cement slurry in pressure tank B. Keep the pressure in pressure tank B constant during the mixing process. After the mixture is evenly mixed, open the pressure relief valve of pressure tank B to allow the foamed slurry to expand under normal pressure, thereby obtaining an ultra-lightweight inorganic high-efficiency thermal insulation material.

6. The method according to claim 5, characterized in that, The stirring time in step 3) is 100-150 seconds.

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