Thermal insulation silica gel foam and preparation method thereof

Abstract

The invention provides a preparation method of heat insulation silica gel foam, and belongs to the technical field of organic silicon foam. According to the raw material formula, the silica gel foam is prepared from two components in equal mass, by adding the modified aerogel composite material, the thermal conductivity of traditional silica gel foam is further reduced, good heat insulation and flame retardant effects are achieved, the flame retardant grade can reach V0, and therefore the silica gel foam has good application prospects as a heat insulation device in a new energy battery pack.

Description

Technical Field

[0001] This invention relates to the field of silicone foam materials, specifically to a silicone foam with good thermal insulation properties and its preparation method. Background Technology

[0002] Silicone foam materials have attracted much attention due to their unique physicochemical properties. Combining the high and low temperature resistance and aging resistance of silicone rubber with the lightweight and flexibility of foam materials, they are widely used in rail transportation, aerospace, and electronics. However, existing silicone foam materials still have some problems, such as high compression set and rapid degradation of mechanical properties at high temperatures. Especially at high temperatures, traditional silicone foam materials can severely shrink, decompose, crack, and even collapse, losing their porous structure and failing to effectively prevent the transfer of flames and heat. To address these issues, researchers have attempted to improve the performance of silicone foam materials by adding various additives and fillers. However, these methods typically involve complex chemical treatments and preparation processes, increasing production costs and potentially causing adverse environmental impacts. Furthermore, while adding some inorganic fillers can improve the fire resistance of the material, excessive addition can reduce thermal insulation performance and disrupt the density and uniformity of the material's pore structure. Therefore, developing a silicone foam material with high mechanical properties, good thermal insulation performance, and ease of preparation at high temperatures is of great significance. This material not only needs to have excellent heat resistance and mechanical properties, but also good flame retardant properties to meet the needs of various harsh application environments. Summary of the Invention

[0003] In view of the deficiencies of the prior art, the purpose of this invention is to provide an organosilicon foam that has high mechanical properties and good thermal insulation performance in high-temperature environments, and is easy to prepare. By adding modified aerogel composite materials, the thermal conductivity of traditional silicone foam is further reduced, achieving good thermal insulation and flame retardant effects.

[0004] The objective of this invention is achieved through the following technical solution: A method for preparing thermally insulating silicone foam, the preparation process of which is as follows: (1) Preparation of modified aerogel composite material: a silica sol is prepared by mixing a silicon source, an alcohol solvent, water, an amino-containing organic ligand and an acid catalyst; a metal source solution is prepared by dissolving a compound containing a transition metal in an organic solvent; the silica sol and the metal source solution are mixed and reacted under the catalysis of ammonium fluoride, and the mixture is gelled, aged, solvent replaced and supercritical dried to obtain the modified aerogel composite material. (2) Preparation of component A: Vinyl silicone oil, 110 glue, α,ω-dihydroxy polydimethylsiloxane, hydroxyl silicone oil, and platinum catalyst are mixed evenly, and then aluminum hydroxide, silica gel color paste and the above modified aerogel composite material are added and mixed thoroughly. After mixing, three-roll milling is performed to obtain component A. Preparation of Component B: Vinyl silicone oil, 110 glue, α,ω-dihydroxy polydimethylsiloxane, hydrogen-containing silicone oil, and inhibitor are mixed evenly, and then aluminum hydroxide and the above modified aerogel composite material are added and mixed thoroughly. After mixing, the mixture is milled in three rollers to obtain Component B. (3) Foaming and molding: Mix equal amounts of component A and component B, calender them by roller pressing, and then vulcanize them to obtain heat-insulating silicone foam.

[0005] The silicon source in step (1) is tetraethyl orthosilicate; the amino-containing organic ligand is 2-aminoterephthalic acid; the transition metal-containing compound is vanadium trichloride; and the organic solvent includes N,N-dimethylformamide and ethanol.

[0006] In the above preparation method, preferably, the mass-volume ratio of TEOS, ethanol, water, aminoterephthalic acid and HCl in step (1) is (10-15)g:(20-30)mL:(4-7)mL:(8-10)g:(0.1-0.3)g, and more preferably 12.5g:25ml:4.5ml:8.2g:0.1g; the mass-volume ratio of N,N-dimethylformamide, ethanol and vanadium trichloride is (10-20)ml:(10-15ml):(0.5-1)g, and more preferably 15ml:10ml:0.78g; the aqueous solution of ammonium fluoride is prepared by 1-2g of ammonium fluoride and 10-15ml of water, preferably 1.6g of ammonium fluoride and 10ml of water.

[0007] In some preferred embodiments, the modified aerogel preparation method is as follows: Under a nitrogen atmosphere, SiO2 sol and a metal source solution are added to an aqueous solution of ammonium fluoride, and the mixture is refluxed at 60-65°C for 2-3 hours. The reacted solution is transferred to a mold and allowed to gel at 40°C for 24 hours. It is then immersed in an ethanol / water (V:V=1:1) solution for aging for 48 hours, followed by solvent replacement with tert-butanol three times, each time for at least 12 hours. Finally, it is supercritically dried with CO2 for at least 6 hours at a temperature of 25-35°C and a pressure of 7.5-8.5 MPa.

[0008] The process includes: sol preparation: tetraethyl orthosilicate (TEOS), ethanol, water, aminoterephthalic acid and a small amount of HCl are mixed and stirred for 30-60 min to obtain SiO2 sol; metal source solution preparation: under a nitrogen atmosphere, N,N-dimethylformamide and ethanol are mixed evenly, vanadium trichloride is added, and ultrasonic dispersion is carried out for 30 min.

[0009] In the above preparation method, preferably, in step (2), component A consists of 25-40 parts vinyl silicone oil, 1-10 parts 110 glue, 10-30 parts α,ω-dihydroxy polydimethylsiloxane, 1-20 parts hydroxy silicone oil, 1-3 parts silica gel color paste, 20-40 parts aluminum hydroxide, 10-20 parts modified aerogel composite material, and 0.01-1 parts platinum catalyst, by mass fraction. Component B consists of 25-40 parts vinyl silicone oil, 1-10 parts 110 glue, 10-40 parts α,ω-dihydroxypolydimethylsiloxane, 5-20 parts hydrogen-containing silicone oil, 20-40 parts aluminum hydroxide, 10-20 parts modified aerogel composite material, and 0.1-1 parts inhibitor.

[0010] In the above preparation method, preferably, the vinyl content in the vinyl silicone oil is 0.01-1 wt%.

[0011] In the above preparation method, preferably, the vinyl content in 110 glue is 0.5-6 wt%.

[0012] In the above preparation method, preferably, the hydroxyl content in α,ω-dihydroxy polydimethylsiloxane is 0.03-2wt%.

[0013] In the above preparation method, preferably, the hydroxyl content in the hydroxyl silicone oil is 1-9 wt%.

[0014] In the above preparation method, preferably, the hydrogen content in the hydrogen-containing silicone oil is 0.05-3 wt%.

[0015] In the above preparation method, preferably, the silica gel pigment is purchased from Shenzhen Longhuixiang Technology Co., Ltd., Shenzhen Taike Technology Co., Ltd., and Foshan Kaller New Materials Co., Ltd.

[0016] In the above preparation method, the preferred platinum catalyst is a Castells platinum catalyst.

[0017] In the above preparation method, preferably, the platinum catalyst content is one or more of 3000ppm and 5000ppm.

[0018] In the above preparation method, preferably, the inhibitor is one or more of 2-methyl-3-butyn-2-ol and ethynylcyclohexanol. In the above preparation method, preferably, in step three, the first vulcanization temperature is 50-80℃ and the time is 5-12 minutes, and the second vulcanization temperature is 150-190℃ and the time is 30-60 minutes.

[0019] The present invention also provides a thermal insulation silicone foam prepared by the above-described preparation method, which has a thermal conductivity of not more than 0.025 W / (m·K), a tensile strength of not less than 0.5 MPa, a flame retardant rating of UL94 V-0, and a density of 450-500 kg / m³. 3 .

[0020] Another technical solution of the present invention is the application of the heat-insulating silicone foam in the preparation of heat-insulating pads for new energy battery packs, heat-insulating layers for electronic devices, or heat-insulating materials for aerospace applications.

[0021] The present invention also provides a modified aerogel composite material for silicone foam, which is prepared by co-gelling silica sol with vanadium-containing metal source solution under ammonium fluoride catalysis, followed by aging, solvent replacement and supercritical drying. The composite material retains its structural integrity after being treated at 400°C for 2 hours, and its thermal conductivity is not higher than 0.015 W / (m·K).

[0022] Beneficial effects Compared with the prior art, the present invention provides a heat-insulating silicone foam, which has the following beneficial effects: 1. The modified aerogel composite material used in this invention further reduces the thermal conductivity of silica aerogel and improves the compatibility between ordinary aerogel and silicone oil through precursor molecular design and dynamic competitive coordination chemical reaction, thereby improving the mechanical properties of silicone foam during the preparation of silicone foam. This invention significantly improves the mechanical properties and stability of silicone foam under high-temperature conditions by optimizing the component ratio and preparation process, effectively solving the problem that traditional silicone foam materials are prone to compression set and mechanical property degradation under high-temperature conditions.

[0023] 2. The silicone foam of the present invention has good thermal insulation properties and can effectively prevent the transfer of flames and heat, overcoming the shortcomings of traditional silicone foam materials that are prone to decomposition, cracking and collapse under high temperature environment.

[0024] 3. By rationally selecting and optimizing the proportions of each component, this invention maintains the compactness and uniformity of the pore structure of the material, thus solving the problem of pore structure destruction caused by excessive addition of inorganic fillers in the prior art. Detailed Implementation

[0025] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions in the embodiments of this application will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments in this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application. Unless otherwise specified, the experimental methods in the following embodiments are conventional methods; the reagents and materials, unless otherwise specified, can be obtained commercially.

[0026] Example 1: Preparation of modified aerogel composite materials Sol preparation: Mix 12.5g TEOS, 25ml ethanol, 4.5ml water, 8.2g 2-aminoterephthalic acid and 0.1g HCl, and stir at room temperature for 30-60min to obtain SiO2 sol; Preparation of metal source solution: Under a nitrogen atmosphere, 15 ml of N,N-dimethylformamide and 10 ml of ethanol were mixed evenly, and then 0.78 g of vanadium trichloride was added. The mixture was then ultrasonically dispersed at room temperature for 30 min. Preparation of modified aerogel: Under a nitrogen atmosphere, SiO2 sol and metal source solution were added to an aqueous solution of ammonium fluoride and refluxed at 60-65℃ for 2-3 hours. The aqueous solution of ammonium fluoride was prepared by mixing 1.6g of ammonium fluoride with 10ml of water. The reacted solution was transferred to a mold and allowed to gel at 40℃ for 24 hours. Then, it was immersed in an ethanol / water (V:V=1:1) solution for aging for 48 hours. Solvent replacement was performed three times using tert-butanol, each time for no less than 12 hours. Finally, it was supercritically dried with CO2 for 8 hours at 30℃ and 8MPa.

[0027] Performance testing: Thermal conductivity: 0.012 W / (m·K) (Hot Disk thermal constant analyzer); Temperature resistance: After treatment at 400℃ for 2 hours, the structure remains intact: the appearance is intact without cracks or sintering, and the dimensional shrinkage rate is 0.7%.

[0028] Example 2: Preparation of foam Preparation of Component A: 32 parts of 0.09 wt% vinyl silicone oil, 12 parts of 2 wt% α,ω-dihydroxy polydimethylsiloxane, 1.5 parts of 1 wt% 110 adhesive, 4 parts of 6 wt% hydroxyl silicone oil, 1 part of silicone pigment (model Longhuixiang Black 81801A), and 0.3 parts of 5000 ppm Castor platinum catalyst were mixed evenly. Then, 36 parts of aluminum hydroxide and 10 parts of the modified aerogel composite material prepared in Example 1 were added. After mixing, the A component was milled twice using a three-roll mill to obtain Component A. Preparation of Component B: 32 parts of 1 wt% vinyl silicone oil, 28 parts of 2 wt% α,ω-dihydroxypolydimethylsiloxane, 1.5 parts of 3 wt% 110 adhesive, 5 parts of 2 wt% hydrogen-containing silicone oil, and 0.5 parts of ethynylcyclohexanol were mixed evenly. Then, 36 parts of aluminum hydroxide and 10 parts of the modified aerogel composite material prepared in Example 1 were added and mixed thoroughly. After mixing, the B component was milled twice using a three-roll mill to obtain Component B.

[0029] Preparation of heat-insulating silicone foam Equal masses of components A and B are weighed in a weighing tank and rapidly mixed. The resulting mixture is coated onto a release film and calendered by a roller with a preset height. The sample is then placed in a 70°C oven for vulcanization for 8 minutes and then transferred to a 190°C oven for vulcanization for 30 minutes to obtain the final sample.

[0030] Performance indicators: tensile strength 0.55 MPa, elongation at break 143%, 25% compressive stress 85 kPa, flame retardant rating V-0, density 490 kg / m³ 3 Water absorption rate 0.8% (23℃×24h), thermal conductivity 0.022W / (m·K).

[0031] Example 3: Preparation of foam Preparation of Component A: 25 parts of 1 wt% vinyl silicone oil, 30 parts of 2 wt% α,ω-dihydroxy polydimethylsiloxane, 6 parts of 0.5 wt% 110 adhesive, 3 parts of 8.5 wt% hydroxyl silicone oil, 2 parts of silicone pigment (model 81801A), and 1 part of 3000 ppm Castel platinum catalyst were mixed evenly. Then, 20 parts of aluminum hydroxide and 20 parts of the modified aerogel composite material prepared in Example 1 were added. After mixing, the A component was milled twice using a three-roll mill to obtain Component A. Preparation of Component B: 28 parts of 0.07 wt% vinyl silicone oil, 40 parts of 1 wt% α,ω-dihydroxypolydimethylsiloxane, 6 parts of 6 wt% 110 adhesive, 7.5 parts of 1.6 wt% hydrogen-containing silicone oil, and 0.5 parts of ethynylcyclohexanol were mixed evenly. Then, 20 parts of aluminum hydroxide and 20 parts of the modified aerogel composite material prepared in Example 1 were added and mixed thoroughly. After mixing, the B component was milled twice using a three-roll mill to obtain Component B.

[0032] Preparation of heat-insulating silicone foam Equal masses of components A and B are weighed in a weighing tank and rapidly mixed. The resulting mixture is coated onto a release film and calendered by a roller with a preset height. The sample is then placed in an 80°C oven for 6 minutes of vulcanization, and then transferred to a 180°C oven for 45 minutes of vulcanization to obtain the final sample.

[0033] Performance indicators: tensile strength 0.57 MPa, elongation at break 151%, 25% compressive stress 86 kPa, flame retardant rating V-0, density 495 kg / m³ 3 Water absorption rate 0.9% (23℃×24h), thermal conductivity 0.024W / (m·K).

[0034] Example 4: Preparation of foam Preparation of Component A: 40 parts of 0.2 wt% vinyl silicone oil, 10 parts of 0.5 wt% α,ω-dihydroxypolydimethylsiloxane, 4 parts of 1 wt% 110 adhesive, 16 parts of 0.8 wt% hydroxyl silicone oil, 1.5 parts of silicone pigment (model 81801A), and 0.8 parts of 5000 ppm Castel platinum catalyst were mixed evenly. Then, 30 parts of aluminum hydroxide and 16 parts of the modified aerogel composite material prepared in Example 1 were added. After mixing, the A component was milled twice using a three-roll mill to obtain Component A. Preparation of Component B: 40 parts of 0.2 wt% vinyl silicone oil, 16 parts of 2 wt% α,ω-dihydroxypolydimethylsiloxane, 4 parts of 5 wt% 110 adhesive, 18 parts of 0.1 wt% hydrogen-containing silicone oil, and 1 part of 2-methyl-3-butyn-2-ol were mixed evenly. Then, 30 parts of aluminum hydroxide and 16 parts of the modified aerogel composite material prepared in Example 1 were added and mixed thoroughly. After mixing, the B component was milled twice using a three-roll mill to obtain Component B.

[0035] Preparation of heat-insulating silicone foam Equal masses of components A and B are weighed in a weighing tank and rapidly mixed. The resulting mixture is coated onto a release film and calendered by a roller with a preset height. The sample is then placed in a 50°C oven for vulcanization for 12 minutes and then transferred to a 150°C oven for vulcanization for 60 minutes to obtain the final sample.

[0036] Performance indicators: tensile strength 0.52 MPa, elongation at break 147%, 25% compressive stress 91 kPa, flame retardant rating V-0, density 488 kg / m³ 3 Water absorption rate 0.7% (23℃×24h), thermal conductivity 0.023W / (m·K).

[0037] Comparative Example 1: Preparation of modified aerogel composite materials Following the preparation method of Example 1, 0.78g of vanadium trichloride was replaced with 1.48g of Zn(NO3)2·6H2O, while other parameters remained unchanged.

[0038] The modified aerogel composite material prepared was subjected to performance testing, and the thermal conductivity was 0.035 W / (m·K) (Hot Disk thermal constant analyzer). Temperature resistance: After treatment at 400℃ for 2 hours, the structure remains intact; the appearance is intact without cracks or sintering, and the dimensional shrinkage rate is 1.9%.

[0039] Preparation of foam Preparation of Component A: 32 parts of 0.09 wt% vinyl silicone oil, 12 parts of 2 wt% α,ω-dihydroxy polydimethylsiloxane, 1.5 parts of 1 wt% 110 adhesive, 4 parts of 6 wt% hydroxyl silicone oil, 1 part of silicone pigment (model 81801A), and 0.3 parts of 5000 ppm Castel platinum catalyst were mixed evenly. Then, 36 parts of aluminum hydroxide and 10 parts of the modified aerogel composite material prepared by replacing Zn(NO3)2·6H2O were added. After mixing, the A component was milled twice using a three-roll mill to obtain Component A. Preparation of Component B: 32 parts of 1 wt% vinyl silicone oil, 28 parts of 2 wt% α,ω-dihydroxypolydimethylsiloxane, 1.5 parts of 3 wt% 110 adhesive, 5 parts of 2 wt% hydrogen-containing silicone oil, and 0.5 parts of ethynylcyclohexanol were mixed evenly. Then, 36 parts of aluminum hydroxide and 10 parts of the modified aerogel composite material prepared by replacing Zn(NO3)2·6H2O were added. After mixing, the B component was milled twice using a three-roll mill to obtain Component B.

[0040] Preparation of heat-insulating silicone foam Equal masses of components A and B are weighed in a weighing tank and rapidly mixed. The resulting mixture is coated onto a release film and calendered by a roller with a preset height. The sample is then placed in a 70°C oven for vulcanization for 8 minutes and then transferred to a 190°C oven for vulcanization for 30 minutes to obtain the final sample.

[0041] Performance indicators: tensile strength 0.40 MPa, elongation at break 123%, 25% compressive stress 87 kPa, flame retardant rating V-0, density 500 kg / m³ 3 Water absorption rate 1.1% (23℃×24h), thermal conductivity 0.057W / (m·K).

[0042] Comparative Example 2 The difference from Example 2 is that the modified aerogel composite material prepared in Example 1 is not added.

[0043] Performance indicators: tensile strength 0.37 MPa, elongation at break 109%, 25% compressive stress 75 kPa, flame retardant rating V-1, density 530 kg / m³ 3Water absorption rate 1.2% (23℃×24h), thermal conductivity 0.063W / (m·K).

[0044] Comparative Example 3 Preparation of modified aerogel composite materials Following the preparation method of Example 1, 8.2g of 2-aminoterephthalic acid was replaced with 3.72g of 2-methylimidazole, while other parameters remained unchanged.

[0045] The modified aerogel composite material prepared was subjected to performance testing, and the thermal conductivity was 0.043 W / (m·K) (Hot Disk thermal constant analyzer). Temperature resistance: After treatment at 400℃ for 2 hours, the appearance edge cracks and the dimensional shrinkage rate is 2.4%.

[0046] Preparation of foam Preparation of Component A: 32 parts of 0.09 wt% vinyl silicone oil, 12 parts of 2 wt% α,ω-dihydroxypolydimethylsiloxane, 1.5 parts of 1 wt% 110 adhesive, 4 parts of 6 wt% hydroxyl silicone oil, 1 part of silicone pigment (model 81801A), and 0.3 parts of 5000 ppm Castel platinum catalyst were mixed evenly. Then, 36 parts of aluminum hydroxide and 10 parts of the modified aerogel composite material prepared by replacing the above with 2-methylimidazolium hydroxide were added. After mixing, the A component was milled twice using a three-roll mill to obtain Component A. Preparation of Component B: 32 parts of 1 wt% vinyl silicone oil, 28 parts of 2 wt% α,ω-dihydroxypolydimethylsiloxane, 1.5 parts of 3 wt% 110 adhesive, 5 parts of 2 wt% hydrogen-containing silicone oil, and 0.5 parts of ethynylcyclohexanol were mixed evenly. Then, 36 parts of aluminum hydroxide and 10 parts of the modified aerogel composite material prepared by replacing 2-methylimidazolium with aluminum hydroxide were added. After mixing, the B component was milled twice using a three-roll mill to obtain Component B.

[0047] Preparation of heat-insulating silicone foam Equal masses of components A and B are weighed in a weighing tank and rapidly mixed. The resulting mixture is coated onto a release film and calendered by a roller with a preset height. The sample is then placed in a 70°C oven for vulcanization for 8 minutes and then transferred to a 190°C oven for vulcanization for 30 minutes to obtain the final sample.

[0048] Performance indicators: tensile strength 0.37 MPa, elongation at break 93%, 25% compressive stress 82 kPa, flame retardant rating V-0, density 469 kg / m³ 3 Water absorption rate 1.1% (23℃×24h), thermal conductivity 0.061W / (m·K).

Claims

1. A method for preparing heat-insulating silicone foam, characterized in that, Includes the following steps: (1) Preparation of modified aerogel composite material: a silica sol is prepared by mixing a silicon source, an alcohol solvent, water, an amino-containing organic ligand and an acid catalyst; a metal source solution is prepared by dissolving a compound containing a transition metal in an organic solvent; the silica sol and the metal source solution are mixed and reacted under the catalysis of ammonium fluoride, and the mixture is gelled, aged, solvent replaced and supercritical dried to obtain the modified aerogel composite material. (2) Preparation of component A: Vinyl silicone oil, 110 glue, α,ω-dihydroxy polydimethylsiloxane, hydroxyl silicone oil, and platinum catalyst are mixed evenly, and then aluminum hydroxide, silica gel color paste and the above modified aerogel composite material are added and mixed thoroughly. After mixing, three-roll milling is performed to obtain component A. Preparation of Component B: Vinyl silicone oil, 110 glue, α,ω-dihydroxy polydimethylsiloxane, hydrogen-containing silicone oil, and inhibitor are mixed evenly, and then aluminum hydroxide and the above modified aerogel composite material are added and mixed thoroughly. After mixing, the mixture is milled in three rollers to obtain Component B. (3) Foaming and molding: Mix equal amounts of component A and component B, calender them by roller pressing, and then vulcanize them to obtain heat-insulating silicone foam.

2. The preparation method according to claim 1, characterized in that: The silicon source in step (1) is tetraethyl orthosilicate; the amino-containing organic ligand is 2-aminoterephthalic acid; the transition metal-containing compound is vanadium trichloride; and the organic solvent includes N,N-dimethylformamide and ethanol.

3. The preparation method according to claim 1, characterized in that: The mass-to-volume ratio of the silicon source, alcohol solvent, water, amino-containing organic ligand and acid catalyst in step (1) is (10-15) g: (20-30) mL: (4-7) mL: (8-10) g: (0.1-0.3) g; the mass-to-volume ratio of N,N-dimethylformamide, ethanol and transition metal-containing compound is (10-20) mL: (10-15) mL: (0.5-1) g.

4. The preparation method according to claim 1, characterized in that: The reaction described in step (1) is carried out under reflux at 60-65°C for 2-3 hours; the amount of ammonium fluoride catalyst is 1-2g of ammonium fluoride dissolved in 10-15mL of water.

5. The preparation method according to any one of claims 1-4, characterized in that: In step two, by mass parts, component A consists of 25-40 parts vinyl silicone oil, 1-10 parts 110 glue, 10-30 parts α,ω-dihydroxypolydimethylsiloxane, 1-20 parts hydroxyl silicone oil, 1-3 parts silica gel color paste, 20-40 parts aluminum hydroxide, 10-20 parts modified aerogel composite material, and 0.01-1 parts platinum catalyst. Component B consists of 25-40 parts vinyl silicone oil, 1-10 parts 110 glue, 10-40 parts α,ω-dihydroxypolydimethylsiloxane, 5-20 parts hydrogen-containing silicone oil, 20-40 parts aluminum hydroxide, 10-20 parts modified aerogel composite material, and 0.1-1 parts inhibitor.

6. The preparation method according to claim 1, characterized in that: Vinyl silicone oil contains 0.01-1 wt% vinyl content, 110 silicone oil contains 0.5-6 wt% vinyl content, α,ω-dihydroxy polydimethylsiloxane contains 0.03-2 wt% hydroxyl content, hydroxyl silicone oil contains 1-9 wt% hydroxyl content, and hydrogen-containing silicone oil contains 0.05-3 wt% hydrogen content. The platinum catalyst is a Castells platinum catalyst, and the inhibitor is one or more of 2-methyl-3-butyn-2-ol and ethynylcyclohexanol.

7. The preparation method according to claim 1, characterized in that, In step three, the vulcanization is a two-stage vulcanization process. The first stage vulcanization temperature is 50-80℃ and the time is 5-12 minutes, while the second stage vulcanization temperature is 150-190℃ and the time is 30-60 minutes.

8. The thermal insulation silicone foam prepared by the method according to any one of claims 1-7 has a thermal conductivity not higher than 0.025 W / (m·K), a tensile strength not lower than 0.5 MPa, a flame retardant rating reaching UL94 V-0, and a density of 450-500 kg / m³. 3 .

9. The application of the thermal insulation silicone foam according to claim 8 in the preparation of thermal insulation pads for new energy battery packs, thermal insulation layers for electronic devices, or thermal insulation materials for aerospace applications.

10. A modified aerogel composite material for silicone foam, characterized in that, It is prepared by co-gelling silica sol with vanadium-containing metal source solution under ammonium fluoride catalysis, followed by aging, solvent replacement and supercritical drying. The composite material retains its structural integrity after being treated at 400℃ for 2 hours, and its thermal conductivity is not higher than 0.015 W / (m·K).