Lightweight high-temperature-ablation-resistant thermal insulation material and preparation method thereof
By using hollow glass microbeads, alumina powder, anhydrous borax powder, alumina fibers and boron-modified phenolic resins in the ablated heat-proof materials, combined with specific mixing and molding processes, the problem of loss of performance of traditional ablated heat-proof materials at high temperatures is solved, and the effects of high strength, thermal insulation performance and high material utilization are achieved.
Patent Information
- Application Number
- CN202411759822.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-03
- Publication Date
- 2025-03-04
AI Technical Summary
Traditional ablation and heat-proof materials have greatly lost their performance under high temperature conditions, making it difficult to take into account both heat-proof efficiency, bulk density, mechanical properties and molding methods.
Lightweight, high-temperature ablation insulation materials are used, and their formulations include hollow glass microbeads, alumina powder, anhydrous borax powder, alumina fibers and boron-modified phenolic resins. Through specific mixing and molding processes, materials with high strength and thermal insulation properties are formed.
The material retains structural integrity at high temperatures, significantly improves the thermal insulation performance, and can be formed directly through a hot press tank. The material utilization rate is high, and the mechanical properties and thermal insulation performance are comprehensively surpassing traditional materials.
Smart Images
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Abstract
Description
Technical Field
[0001] The invention belongs to the technical field of composite materials, and in particular relates to a lightweight, high-temperature resistant ablation insulation material and a preparation method thereof. Background Art
[0002] Traditional ablative heat protection materials are difficult to meet the heat protection requirements in terms of heat protection efficiency, volume density, mechanical properties and molding methods. The main reason is that the glass beads and phenolic aerogel in the material melt and vaporize under high temperature conditions, resulting in microstructure destruction and significant loss of performance. For example, the heat protection panels of current aircraft largely use phenolic fiberglass honeycomb sandwich structures filled with FG5 low-density ablative materials. For complex hypersonic aircraft, if FG5 heat protection panels are used as heat protection materials, first, the material needs to be cut and processed, and the material utilization rate is less than 30%, resulting in a lot of waste; second, the material thickness must be increased to adapt to the high temperature zone of 1600℃ and 400s, resulting in a significant increase in the weight of the aircraft; third, splicing is required, resulting in mechanical defects. Therefore, it is urgent to develop new lightweight heat protection materials to meet the needs of new thermal environments. Summary of the invention
[0003] In order to solve the technical problems in the prior art that ablative heat-insulating materials are difficult to balance in terms of heat-insulating efficiency, volume density, mechanical properties and molding methods, the present invention provides a lightweight, high-temperature resistant ablative heat-insulating material and a preparation method thereof.
[0004] In order to achieve the purpose, the present invention adopts the following technical scheme:
[0005] The present invention first provides a lightweight high temperature resistant ablation insulation material, wherein the raw materials thereof are composed of the following components in terms of mass fraction:
[0006]
[0007] Preferably, the particle size of the hollow glass microspheres is not greater than 80 μm and the tap density is not greater than 300 kg / m 3 .
[0008] Preferably, the phenolic resin is a boron-modified phenolic resin having a viscosity of no more than 20,000 mPas and a solid content of no less than 70%.
[0009] Preferably, the particle size of the aluminum oxide powder is not greater than 50 μm and the purity is not less than 98%.
[0010] Preferably, the alumina fibers are chopped fibers with an alumina content of not less than 80% and a length of 5 mm to 30 mm.
[0011] Preferably, the purity of the anhydrous borax is not less than 90% and the particle size is not greater than 50 μm.
[0012] Preferably, the accelerator is at least one of glycerol, butanethrol and pentaerythritol.
[0013] The present invention also provides a method for preparing a lightweight high-temperature resistant ablative thermal insulation material, which is used to prepare the lightweight high-temperature resistant ablative thermal insulation material, and is specifically operated according to the following steps:
[0014] S1: Pour hollow glass microspheres, alumina powder and anhydrous borax powder into a planetary stirring kettle, mix at 20-30°C for 20-40 minutes, then add accelerator and phenolic resin, continue to mix at 20-30°C for 20-40 minutes to obtain powder;
[0015] S2: pouring the alumina fiber and the powder from step S1 into a horizontal stirring tank, mixing at 20-30° C. for 20-40 min to obtain a mixture;
[0016] S3: evenly spread the mixture on the release film with a thickness of 10-20 mm;
[0017] S4: The laid material is pressed to a thickness of 40%-60% of the original thickness by a roller press to obtain a final product.
[0018] Compared with the prior art, the present invention has the following beneficial effects:
[0019] 1. The thermal insulation material of the present invention has the characteristics of light weight, high strength, heat insulation and ablation resistance, which solves the problem that the ablation material in the prior art is difficult to achieve the three characteristics of light weight, high strength and heat insulation at the same time.
[0020] 2. In the system of the thermal insulation material of the present invention: through the borax bead effect, at high temperature, borax dissolves alumina and infiltrates into the surface of molten glass beads, greatly increasing the melt strength of the glass beads, so that the structural integrity is retained at high temperature, thereby improving the thermal insulation performance of the material as a whole. Through the reduction reaction of borax and carbon, boron carbide crystals are formed in the carbonized phenolic resin, improving the structural integrity of the carbonized layer, thereby improving the thermal insulation performance of the material as a whole.
[0021] 3. The thermal insulation material of the present invention can be directly integrally formed by autoclave molding, compression molding, etc. to prepare special-shaped parts with complex morphology, and the material utilization rate exceeds 95%.
[0022] 4. The present invention provides new ideas and new directions for technological progress in this field, and greatly promotes technological progress in this field. DETAILED DESCRIPTION
[0023] In order to further understand the present invention, preferred embodiments of the present invention are described below in conjunction with examples, but it should be understood that these descriptions are only for further illustrating the features and advantages of the present invention rather than limiting the patent claims of the present invention.
[0024] 1. Preparation of thermal insulation materials
[0025] The raw materials used in Examples 1-5 and Comparative Examples 1-4 are shown in Table 1, and the formulas are shown in Table 2.
[0026] Table 1 Raw material information
[0027]
[0028] Table 2 Formula of Examples 1-5 and Comparative Examples 1-4
[0029]
[0030] The preparation process of the thermal insulation material in Examples 1-5 and Comparative Examples 1-4 is as follows:
[0031] S1: Pour hollow glass microspheres, alumina powder and anhydrous borax powder into a planetary stirring kettle, mix at 25°C for 20-40 minutes, then add accelerator and phenolic resin, and continue mixing at 25°C for 30 minutes to obtain powder.
[0032] S2: Pour the alumina fiber and the powder of step S1 into a horizontal stirring tank, mix at 25° C. for 30 minutes, and obtain a mixture.
[0033] S3: Spread the mixture evenly on the release film with a thickness of 10 mm.
[0034] S5: The laid material is pressed to a thickness of 5 mm by a roller press to obtain a final product.
[0035] Comparative Example 5 is a commercially available FG5 thermal insulation material, and Comparative Examples 6-7 are CF / SiOC / PR composite materials and CF / TiO2 / PR composite materials described in the document "Li Chunlai - Preparation and Structural Performance Study of Low-density Fiber Reinforced Phenolic Aerogel - Harbin Institute of Technology".
[0036] 2. Performance Test
[0037] Test sample preparation:
[0038] (1) The products obtained in Examples 1-5 and Comparative Examples 1-4 were laid in 4 layers in a 150 mm × 150 mm × 25 mm mold, and the laid material was compressed to a thickness of 14 mm on a flat vulcanizer, cured at 180° C. for 5 h, and cut into 140 mm × 25 mm × 14 mm sheets after being taken out; Comparative Example 5 (FG5) was directly cut into 140 mm × 25 mm × 14 mm sheets; Comparative Examples 6-7 were directly prepared into 140 mm × 25 mm × 14 mm sheets according to the optimal ratio process described in the literature; used for tensile testing, the test speed was 2 mm / min.
[0039] (2) The products obtained in Examples 1-5 and Comparative Examples 1-4 were laid in 4 layers in a 150mm×150mm×25mm mold, and the laid material was compressed to a thickness of 14mm on a flat vulcanizer, cured at 180°C for 5h, and cut into 140mm×140mm×14mm sheets after being taken out; Comparative Example 5 (FG5) was directly cut into 140mm×140mm×14mm sheets; Comparative Examples 6-7 were directly prepared into 140mm×140mm×14mm sheets according to the optimal ratio process described in the literature; used for ablation test, the test method was to measure the center thickness change and the highest temperature of the back after ablation at 1700°C for 400s; used for thermal conductivity test, the test method was the transient hot wire method, and the test temperature was 25°C.
[0040] (3) The products obtained in Examples 1-5 and Comparative Examples 1-4 were laid out in 16 layers in a 150 mm × 150 mm × 85 mm mold, and the laid material was compressed to a thickness of 56 mm on a flat vulcanizer, cured at 180° C. for 5 h, and cut into 56 mm × 56 mm × 56 mm blocks after being taken out; Comparative Example 5 (FG5) was directly cut into 56 mm × 56 mm × 56 mm blocks; Comparative Examples 6-7 were directly prepared into 56 mm × 56 mm × 56 mm blocks according to the optimal ratio process described in the literature; they were used for density and compression tests at a test speed of 2 mm / min.
[0041] All test results are shown in Table 3.
[0042] Table 3 Test results
[0043]
[0044] Comparison of the test results of Examples 1-5 and Comparative Examples 5-7 shows that, except for tensile properties, the other properties of the present invention are all superior to FG5. This is because the strength of FG5 is only provided by the aramid honeycomb skeleton, and the phenolic aerogel and glass microspheres only provide thermal insulation performance. Moreover, the phenolic aerogel and glass microspheres are not protected by the reinforcement system, and the microstructures quickly decompose and collapse at high temperatures, losing thermal insulation performance. The present invention uses resin, inorganic particles and short fibers to fill the gaps in the glass microspheres, so that the material is stressed as a whole, stress concentration is reduced, and mechanical properties are greatly improved. Moreover, the present invention improves the melt strength of the glass microspheres by introducing the borax bead effect, and the boron-carbon reduction reaction inhibits the gasification of the carbonized layer, greatly reducing the decomposition and collapse rate of the material microstructure at high temperatures, and significantly improving the thermal insulation performance of the material. Comparative Examples 6-7 also have the same problem. The strength is only provided by disordered interlaced fibers, and there is stress concentration when stressed. The thermal insulation structure is not protected by the reinforcement system, decomposes and collapses at high temperatures, and the mechanical properties and thermal insulation performance are far lower than those of the present invention. The material of comparative example 5 is honeycomb, which can only be formed into a plate, requires cutting, and has low material utilization. The synthesis process of comparative examples 6-7 is complicated and not practical. However, the present invention presents a form similar to prepreg, has the same construction method as prepreg, has high material utilization, and can form complex parts in one piece.
[0045] The comparison of the test results of Examples 1-5 and Comparative Examples 1-4 shows that the borax bead reaction system composed of alumina powder and anhydrous borax can well enhance the melt strength of glass microbeads, thereby improving high temperature resistance and thermal insulation performance. The promoter can promote the redox reaction of borax and carbon layer, reduce carbon layer gasification, and improve thermal insulation performance.
Claims
1. A lightweight, high temperature resistant ablative insulation material, characterized in that: The composition of each raw material by mass is as follows:
2. The lightweight high temperature resistant ablative insulation material according to claim 1, characterized in that: The particle size of the hollow glass microspheres is not greater than 80 μm, and the tap density is not greater than 300 kg / m 3 .
3. The lightweight high temperature resistant ablative insulation material according to claim 1, characterized in that: The phenolic resin is a boron-modified phenolic resin with a viscosity of no more than 20000 mPas and a solid content of no less than 70%.
4. The lightweight high temperature resistant ablative insulation material according to claim 1, characterized in that: The particle size of the aluminum oxide powder is no more than 50 μm and the purity is no less than 98%.
5. The lightweight high temperature resistant ablative insulation material according to claim 1, characterized in that: The alumina fibers are short-cut fibers with an alumina content of not less than 80% and a length of 5 mm to 30 mm.
6. The lightweight high temperature resistant ablative insulation material according to claim 1, characterized in that: The purity of the anhydrous borax is not less than 90% and the particle size is not greater than 50 μm.
7. The lightweight high temperature resistant ablative insulation material according to claim 1, characterized in that: The accelerator is at least one of glycerol, butanethrol and pentaerythritol.
8. A method for preparing a lightweight, high-temperature resistant ablative thermal insulation material, used for preparing the lightweight, high-temperature resistant ablative thermal insulation material according to any one of claims 1 to 7, characterized in that: Follow these steps: S1: Pour hollow glass microspheres, alumina powder and anhydrous borax powder into a planetary stirring kettle, mix at 20-30°C for 20-40 minutes, then add accelerator and phenolic resin, continue to mix at 20-30°C for 20-40 minutes to obtain powder; S2: pouring the alumina fiber and the powder from step S1 into a horizontal stirring tank, mixing at 20-30° C. for 20-40 min to obtain a mixture; S3: evenly spread the mixture on the release film with a thickness of 10-20 mm; S4: The laid material is pressed to a thickness of 40%-60% of the original thickness by a roller press to obtain a final product.