Highly flame-retardant ceramic silicone rubber and preparation method thereof

Abstract

The invention discloses a highly flame-retardant ceramic silicone rubber and a preparation method thereof, wherein the highly flame-retardant ceramic silicone rubber comprises the following raw materials in parts by weight: 100 parts of silicone rubber matrix, 30-50 parts of white carbon black, 5-10 parts of hydroxy silicone oil, 1-3 parts of coupling agent, 10-20 parts of ceramic filler, 1-5 parts of vulcanizing agent, 10-30 parts of flux, and 4-8 parts of flame retardant; wherein the ceramic filler comprises the following raw materials in parts by weight: 10-30 parts of coal gasification carbon residue, 20-40 parts of Al2O3, 10-30 parts of Cr2O7, 20-40 parts of TiO2, and 5-15 parts of Li2O. The ceramic silicone rubber of the present invention has excellent flame retardant properties, a lower porcelain-forming temperature, and a wide range of applications.

Description

Technical Field

[0001] The invention relates to the technical field of flame retardant materials, and in particular to highly flame retardant ceramic silicone rubber and a preparation method thereof. Background Art

[0002] Ceramic silicone rubber is widely used in aerospace, electronics, and healthcare due to its high-temperature ceramicization and good electrical insulation properties. Currently, the preparation of ceramic silicone rubber is mainly through adding ceramic fillers, vulcanizers, fluxing agents, etc. to silicone rubber and mixing them. However, for existing ceramic silicone rubber, the flame retardant performance is still not good enough, which limits the application field of ceramic silicone rubber. Therefore, it is urgent to develop a new ceramic silicone rubber to improve its flame retardant performance. Summary of the invention

[0003] Based on the technical problems existing in the background technology, the present invention proposes a highly flame retardant ceramic silicone rubber and a preparation method thereof, which has excellent flame retardant properties.

[0004] The highly flame-retardant ceramic silicone rubber provided by the present invention comprises the following raw materials in parts by weight: 100 parts of silicone rubber matrix, 30-50 parts of white carbon black, 5-10 parts of hydroxy silicone oil, 1-3 parts of coupling agent, 10-20 parts of ceramic filler, 1-5 parts of vulcanizing agent, 10-30 parts of flux, and 4-8 parts of flame retardant;

[0005] The ceramic filler comprises the following raw materials in parts by weight: 10-30 parts of coal gasification carbon residue, 20-40 parts of Al2O3, 10-30 parts of Cr2O7, 20-40 parts of TiO2 and 5-15 parts of Li2O.

[0006] Preferably, the silicone rubber matrix is ​​one of methyl vinyl silicone rubber, methyl phenyl vinyl silicone rubber, fluorosilicone rubber and dimethyl silicone rubber.

[0007] Preferably, the vulcanizing agent is one or more of 2,4-dichlorobenzoyl peroxide, dimethyl-(tert-butylperoxyisopropyl)benzene and N,N'-m-phenylene bismaleimide.

[0008] Preferably, the flux is one or more of glass powder, boron trioxide and zinc borate.

[0009] Preferably, the flame retardant is compounded by hydroxyapatite ultra-long nanowires and ammonium polyphosphate@chitosan@Si flame retardant in a mass ratio of 4:1-16.

[0010] The preparation method of the highly flame-retardant ceramic silicone rubber proposed by the present invention comprises the following steps:

[0011] S1: Add the silicone rubber matrix into the kneader and knead for 3-6 minutes, then add white carbon black and hydroxy silicone oil for mixing;

[0012] S2: adding coupling agent, ceramic filler, flux and flame retardant to the mixed material after S1 mixing and continuing mixing;

[0013] S3: vacuum treating the mixed material in S2, and adding a vulcanizing agent to mix the rubber material in an open mill after the rubber material is cooled;

[0014] S4: The material mixed in S3 is pressed into sheets, heated and vulcanized on a flat vulcanizer, and then vulcanized again in an oven to obtain highly flame-retardant ceramic silicone rubber.

[0015] Preferably, the mixing temperature in S1 is 60-90° C., and the mixing time is 20-30 min.

[0016] Preferably, the mixing temperature in S2 is 60-90° C. and the mixing time is 60-120 min.

[0017] Preferably, the temperature of the vacuum treatment in S3 is 90-110° C., the vacuum degree is -0.1 to -0.05 MPa, and the time of the vacuum treatment is 20-30 min; the temperature of the mixing in S3 is 20-30° C., and the time is 10-20 min.

[0018] Preferably, the temperature of the vulcanizing machine for heating vulcanization in S4 is 140-180°C, the time is 20-40 min, and the pressure is 10-15 MPa; the temperature of the secondary vulcanization is 180-200°C, and the time is 60-180 min.

[0019] Beneficial technical effects of the present invention:

[0020] (1) The ceramic filler added in the present invention is composed of coal gasification carbon residue, Al2O3, Cr2O7, TiO2 and Li2O, which is easy to form a bridging structure, thereby achieving the purpose of fire retardancy, and in the process of forming ceramics, a part of the Cr in the +7 valence state of Cr2O7 is reduced to Cr in the +3 valence state, thereby making the ceramic silicone rubber ceramic forming temperature lower, further improving the flame retardant effect; the coal gasification carbon residue of the present invention contains a large number of pores, which is easier to form a bridging structure with the remaining ceramic fillers, thereby further improving the ceramic forming performance.

[0021] (2) The present invention also adds a flame retardant to the ceramic silicone rubber to further improve the flame retardant properties of the ceramic silicone rubber. The flame retardant is composed of hydroxyapatite ultra-long nanowires and ammonium polyphosphate @ chitosan @ Si flame retardant, which has a synergistic effect in improving the flame retardant properties of the ceramic silicone rubber, so that the ceramic silicone rubber can achieve excellent flame retardant properties with the addition of a small amount of flame retardant. DETAILED DESCRIPTION

[0022] The preparation method of the ammonium polyphosphate @ chitosan @ Si flame retardant of the present invention is as follows: 100g of chitosan (CS) is dissolved in a 1wt% acetic acid solution, 1kg of ammonium polyphosphate (APP) is dispersed in 2L of deionized water, and then the acetic acid solution in which CS is dissolved is added, and APP@CS is obtained through centrifugal precipitation and washing; APP@CS is dispersed in 2L of deionized water; 10g of Si-COOH is dissolved in ammonia water and the pH is adjusted to 8, and then the mixture is added to the mixed solution in which APP@CS is dissolved, and the ammonium polyphosphate @ chitosan @ Si flame retardant with carboxylated silicone oil (Si-COOH) coated on the surface of APP and CS is obtained through stirring, washing, centrifugation and drying.

[0023] The synthesis method of Si-COOH is as follows: 40g toluene, 20g PMHS and chloroplatinic acid hexahydrate are mixed and heated to 80°C under a nitrogen atmosphere. Then 30g MMA is slowly dripped into the solution and heated to 140°C for reaction for 30h. The product is distilled under reduced pressure, washed, and treated. Then 100mL 10% NaOH is added, heated to 100°C, hydrolyzed for 2h and methanol is fractionated. Finally, hydrochloric acid is added to the reaction solution to adjust the pH to 6. The precipitated product is washed with water and dried to obtain Si-COOH.

[0024] The coal gasification carbon residue of the present invention is obtained by acidification treatment of gasification fine slag with hydrofluoric acid and hydrochloric acid in sequence; the coupling agent of the present invention is KH560 silane coupling agent; methyl vinyl silicone rubber is purchased from Dongjue Silicone (Nanjing) Co., Ltd., model 110-1S; hydroxyapatite ultra-long nanowires are purchased from Suzhou Beike New Materials Technology Co., Ltd.; glass powder is purchased from Shijiazhuang Zhenghuang Mineral Products Co., Ltd., 200 mesh; hydroxy silicone oil is purchased from Henan Yiyangyi Trading Co., Ltd., model JF-203.

[0025] Example 1

[0026] The highly flame-retardant ceramic silicone rubber proposed by the present invention comprises the following raw materials in parts by weight: 100 parts of silicone rubber matrix, 40 parts of white carbon black, 8 parts of hydroxy silicone oil, 2 parts of coupling agent, 15 parts of ceramic filler, 3 parts of vulcanizing agent, 20 parts of flux, and 6 parts of flame retardant;

[0027] The ceramic filler comprises the following raw materials in parts by weight: 20 parts of coal gasification carbon residue, 30 parts of Al2O3, 20 parts of Cr2O7, 30 parts of TiO2 and 10 parts of Li2O.

[0028] The silicone rubber matrix is ​​methyl vinyl silicone rubber; the vulcanizing agent is 2,4-dichlorobenzoyl peroxide; and the flux is glass powder.

[0029] The flame retardant is compounded by hydroxyapatite ultra-long nanowires and ammonium polyphosphate@chitosan@Si flame retardant in a mass ratio of 1:1.

[0030] The preparation method of the highly flame-retardant ceramic silicone rubber proposed by the present invention comprises the following steps:

[0031] S1: Add the silicone rubber matrix into the kneader and knead for 5 minutes, then add white carbon black and hydroxy silicone oil for mixing;

[0032] S2: adding coupling agent, ceramic filler, flux and flame retardant to the mixed material after S1 mixing and continuing mixing;

[0033] S3: vacuum treating the mixed material in S2, and adding a vulcanizing agent to mix the rubber material in an open mill after the rubber material is cooled;

[0034] S4: The material mixed in S3 is pressed into sheets, heated and vulcanized on a flat vulcanizer, and then vulcanized again in an oven to obtain highly flame-retardant ceramic silicone rubber.

[0035] The mixing temperature in S1 was 75°C and the mixing time was 25 min.

[0036] The mixing temperature in S2 is 75°C and the mixing time is 90 minutes.

[0037] The temperature of vacuum treatment in S3 is 98°C, the vacuum degree is -0.08MPa, and the time of vacuum treatment is 25min; the temperature of mixing in S3 is 25°C, and the time is 15min.

[0038] The temperature of the vulcanizer heating vulcanization in S4 is 160°C, the time is 30 minutes, and the pressure is 13MPa; the temperature of the secondary vulcanization is 190°C, and the time is 120 minutes.

[0039] Example 2

[0040] The highly flame-retardant ceramic silicone rubber proposed by the present invention comprises the following raw materials in parts by weight: 100 parts of silicone rubber matrix, 30 parts of white carbon black, 5 parts of hydroxy silicone oil, 1 part of coupling agent, 10 parts of ceramic filler, 1 part of vulcanizing agent, 10 parts of flux, and 4 parts of flame retardant;

[0041] The ceramic filler comprises the following raw materials in parts by weight: 10 parts of coal gasification carbon residue, 20 parts of Al2O3, 10 parts of Cr2O7, 20 parts of TiO2 and 5 parts of Li2O.

[0042] The silicone rubber matrix is ​​methylphenyl vinyl silicone rubber; the vulcanizing agent is dimethyl-(tert-butylperoxyisopropyl)benzene; and the fluxing agent is boron trioxide.

[0043] The flame retardant is compounded by hydroxyapatite ultra-long nanowires and ammonium polyphosphate@chitosan@Si flame retardant in a mass ratio of 4:1.

[0044] The preparation method of the highly flame-retardant ceramic silicone rubber proposed by the present invention comprises the following steps:

[0045] S1: Add the silicone rubber matrix into the kneader and knead for 3 minutes, then add white carbon black and hydroxy silicone oil for mixing;

[0046] S2: adding coupling agent, ceramic filler, flux and flame retardant to the mixed material after S1 mixing and continuing mixing;

[0047] S3: vacuum treating the mixed material in S2, and adding a vulcanizing agent to mix the rubber material in an open mill after the rubber material is cooled;

[0048] S4: The material mixed in S3 is pressed into sheets, heated and vulcanized on a flat vulcanizer, and then vulcanized again in an oven to obtain highly flame-retardant ceramic silicone rubber.

[0049] The mixing temperature in S1 was 60°C and the mixing time was 20 min.

[0050] The mixing temperature in S2 is 60°C and the mixing time is 60 minutes.

[0051] The temperature of the vacuum treatment in S3 is 90°C, the vacuum degree is -0.1MPa, and the time of the vacuum treatment is 20min; the temperature of the mixing in S3 is 20°C, and the time is 10min.

[0052] The temperature of the vulcanizer heating vulcanization in S4 is 140°C, the time is 20 minutes, and the pressure is 10MPa; the temperature of the secondary vulcanization is 180°C, and the time is 60 minutes.

[0053] Example 3

[0054] The highly flame-retardant ceramic silicone rubber proposed by the present invention comprises the following raw materials in parts by weight: 100 parts of silicone rubber matrix, 50 parts of white carbon black, 10 parts of hydroxy silicone oil, 3 parts of coupling agent, 20 parts of ceramic filler, 5 parts of vulcanizing agent, 30 parts of flux, and 8 parts of flame retardant;

[0055] The ceramic filler comprises the following raw materials in parts by weight: 30 parts of coal gasification carbon residue, 40 parts of Al2O3, 30 parts of Cr2O7, 40 parts of TiO2 and 15 parts of Li2O.

[0056] The silicone rubber matrix is ​​methyl vinyl silicone rubber; the vulcanizing agent is 2,4-dichlorobenzoyl peroxide; and the flux is zinc borate.

[0057] The flame retardant is compounded by hydroxyapatite ultra-long nanowires and ammonium polyphosphate@chitosan@Si flame retardant in a mass ratio of 1:4.

[0058] The preparation method of the highly flame-retardant ceramic silicone rubber proposed by the present invention comprises the following steps:

[0059] S1: Add the silicone rubber matrix into the kneader and knead for 6 minutes, then add white carbon black and hydroxy silicone oil for mixing;

[0060] S2: adding coupling agent, ceramic filler, flux and flame retardant to the mixed material after S1 mixing and continuing mixing;

[0061] S3: vacuum treating the mixed material in S2, and adding a vulcanizing agent to mix the rubber material in an open mill after the rubber material is cooled;

[0062] S4: The material mixed in S3 is pressed into sheets, heated and vulcanized on a flat vulcanizer, and then vulcanized again in an oven to obtain highly flame-retardant ceramic silicone rubber.

[0063] The mixing temperature in S1 was 90°C and the mixing time was 30 min.

[0064] The mixing temperature in S2 is 90°C and the mixing time is 120 min.

[0065] The temperature of the vacuum treatment in S3 is 110°C, the vacuum degree is -0.05MPa, and the time of the vacuum treatment is 30min; the temperature of the mixing in S3 is 30°C, and the time is 20min.

[0066] The temperature of the vulcanizer heating vulcanization in S4 is 180°C, the time is 40 minutes, and the pressure is 15MPa; the temperature of the secondary vulcanization is 200°C, and the time is 180 minutes.

[0067] Comparative Example 1

[0068] The highly flame-retardant ceramic silicone rubber proposed by the present invention comprises the following raw materials in parts by weight: 100 parts of silicone rubber matrix, 40 parts of white carbon black, 8 parts of hydroxy silicone oil, 2 parts of coupling agent, 15 parts of ceramic filler, 3 parts of vulcanizing agent, 20 parts of flux, and 6 parts of flame retardant;

[0069] The ceramic filler comprises the following raw materials in parts by weight: 20 parts of coal gasification carbon residue, 30 parts of Al2O3, 20 parts of Cr2O7, 30 parts of TiO2 and 10 parts of Li2O.

[0070] The silicone rubber matrix is ​​methyl vinyl silicone rubber; the vulcanizing agent is 2,4-dichlorobenzoyl peroxide; and the flux is glass powder.

[0071] The flame retardant is compounded by hydroxyapatite ultra-long nanowires and ammonium polyphosphate@chitosan@Si flame retardant in a mass ratio of 1:1.

[0072] The preparation method of the highly flame-retardant ceramic silicone rubber proposed by the present invention is the same as that of Example 1.

[0073] Comparative Example 2

[0074] The highly flame-retardant ceramic silicone rubber proposed by the present invention comprises the following raw materials in parts by weight: 100 parts of silicone rubber matrix, 40 parts of white carbon black, 8 parts of hydroxy silicone oil, 2 parts of coupling agent, 15 parts of ceramic filler, 3 parts of vulcanizing agent, 20 parts of flux, and 6 parts of flame retardant;

[0075] The ceramic filler comprises the following raw materials in parts by weight: 20 parts of gasification fine slag (the coal gasification carbon residue in Example 1 is not acidified), 30 parts of Al2O3, 20 parts of Cr2O7, 30 parts of TiO2 and 10 parts of Li2O.

[0076] The silicone rubber matrix is ​​methyl vinyl silicone rubber; the vulcanizing agent is 2,4-dichlorobenzoyl peroxide; and the flux is glass powder.

[0077] The flame retardant is compounded by hydroxyapatite ultra-long nanowires and ammonium polyphosphate@chitosan@Si flame retardant in a mass ratio of 1:1.

[0078] The preparation method of the highly flame-retardant ceramic silicone rubber proposed by the present invention is the same as that of Example 1.

[0079] Comparative Example 3

[0080] The highly flame-retardant ceramic silicone rubber proposed by the present invention comprises the following raw materials in parts by weight: 100 parts of silicone rubber matrix, 40 parts of white carbon black, 8 parts of hydroxy silicone oil, 2 parts of coupling agent, 15 parts of ceramic filler, 3 parts of vulcanizing agent, 20 parts of flux, and 6 parts of flame retardant;

[0081] The ceramic filler comprises the following raw materials in parts by weight: 20 parts of coal gasification carbon residue, 30 parts of Al2O3, 30 parts of TiO2 and 10 parts of Li2O.

[0082] The silicone rubber matrix is ​​methyl vinyl silicone rubber; the vulcanizing agent is 2,4-dichlorobenzoyl peroxide; and the flux is glass powder.

[0083] The flame retardant is compounded by hydroxyapatite ultra-long nanowires and ammonium polyphosphate@chitosan@Si flame retardant in a mass ratio of 1:1.

[0084] The preparation method of the highly flame-retardant ceramic silicone rubber proposed by the present invention is the same as that of Example 1.

[0085] Comparative Example 4

[0086] The highly flame-retardant ceramic silicone rubber proposed by the present invention comprises the following raw materials in parts by weight: 100 parts of silicone rubber matrix, 40 parts of white carbon black, 8 parts of hydroxy silicone oil, 2 parts of coupling agent, 15 parts of ceramic filler, 3 parts of vulcanizing agent, 20 parts of flux, and 6 parts of flame retardant;

[0087] The ceramic filler comprises the following raw materials in parts by weight: 20 parts of coal gasification carbon residue, 30 parts of Al2O3, 20 parts of Cr2O7, and 30 parts of TiO2.

[0088] The silicone rubber matrix is ​​methyl vinyl silicone rubber; the vulcanizing agent is 2,4-dichlorobenzoyl peroxide; and the flux is glass powder.

[0089] The flame retardant is compounded by hydroxyapatite ultra-long nanowires and ammonium polyphosphate@chitosan@Si flame retardant in a mass ratio of 1:1.

[0090] The preparation method of the highly flame-retardant ceramic silicone rubber proposed by the present invention is the same as that of Example 1.

[0091] Comparative Example 5

[0092] The highly flame-retardant ceramic silicone rubber proposed by the present invention comprises the following raw materials in parts by weight: 100 parts of silicone rubber matrix, 40 parts of white carbon black, 8 parts of hydroxy silicone oil, 2 parts of coupling agent, 15 parts of ceramic filler, 3 parts of vulcanizing agent, 20 parts of flux, and 6 parts of flame retardant;

[0093] The ceramic filler comprises the following raw materials in parts by weight: 20 parts of coal gasification carbon residue, 30 parts of Al2O3, 20 parts of Cr2O7, 30 parts of TiO2 and 10 parts of Li2O.

[0094] The silicone rubber matrix is ​​methyl vinyl silicone rubber; the vulcanizing agent is 2,4-dichlorobenzoyl peroxide; and the flux is glass powder.

[0095] The flame retardant is ultra-long hydroxyapatite nanowires.

[0096] The preparation method of the highly flame-retardant ceramic silicone rubber proposed by the present invention is the same as that of Example 1.

[0097] Comparative Example 6

[0098] The highly flame-retardant ceramic silicone rubber proposed by the present invention comprises the following raw materials in parts by weight: 100 parts of silicone rubber matrix, 40 parts of white carbon black, 8 parts of hydroxy silicone oil, 2 parts of coupling agent, 15 parts of ceramic filler, 3 parts of vulcanizing agent, 20 parts of flux, and 6 parts of flame retardant;

[0099] The ceramic filler comprises the following raw materials in parts by weight: 20 parts of coal gasification carbon residue, 30 parts of Al2O3, 20 parts of Cr2O7, 30 parts of TiO2 and 10 parts of Li2O.

[0100] The silicone rubber matrix is ​​methyl vinyl silicone rubber; the vulcanizing agent is 2,4-dichlorobenzoyl peroxide; and the flux is glass powder.

[0101] The flame retardant is ammonium polyphosphate @ chitosan @ Si flame retardant.

[0102] The preparation method of the highly flame-retardant ceramic silicone rubber proposed by the present invention is the same as that of Example 1.

[0103] The flame retardant properties and ceramic forming temperatures of the ceramic silicone rubber prepared in Example 1 and Comparative Examples 1-6 were measured, and the results are shown in Table 1.

[0104] The limiting oxygen index test refers to GB / T10707-2008, and the instrument is JF-3 limiting oxygen index instrument; the test method for the temperature required for ceramicization is: calcine the sample in the muffle furnace at different temperatures for 45 minutes, and judge whether it is ceramic by knocking and listening for porcelain sound, so as to determine the lowest temperature for the sample to form ceramics.

[0105] Table 1 Ceramic silicone rubber performance test results

[0106] Group LOI% Porcelain forming temperature / ℃ Example 1 36.4 450 Comparative Example 1 32.8 535 Comparative Example 2 33.3 510 Comparative Example 3 30.8 720 Comparative Example 4 31.4 780 Comparative Example 5 27.6 495 Comparative Example 6 28.5 475

[0107] It can be seen from the test results of Example 1 that the ceramic silicone rubber prepared in the present application has excellent flame retardant properties and a lower ceramic forming temperature; it can be seen from the test results of Example 1 and Comparative Examples 1 and 2 that the ceramic forming performance of the present invention is further improved by adding coal gasification carbon residue, because the gasified fine slag treated by acidification contains a large number of pores and is more likely to form a bridging structure with the remaining ceramic fillers; it can be seen from the test results of Example 1 and Comparative Examples 3 and 4 that Cr2O7 and Li2O in the ceramic filler of the present invention are key components, and in the presence of Li2O Under such circumstances, in the ceramic silicone rubber ceramic process, a part of the Cr2O7 with a valence state of +7 will be reduced to Cr with a valence state of +3, thereby lowering the ceramic silicone rubber ceramic forming temperature and further improving the flame retardant effect; it can be seen from the test results of Example 1 and Comparative Examples 5 and 6 that the flame retardant of the present application is composed of hydroxyapatite ultra-long nanowires and ammonium polyphosphate @ chitosan @ Si flame retardant, which has a synergistic promoting effect in improving the flame retardant properties of ceramic silicone rubber, so that the ceramic silicone rubber can achieve excellent flame retardant properties with the addition of a small amount of flame retardant.

[0108] The above are only 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 in the protection scope of the present invention.

Claims

1. Highly flame retardant ceramic silicone rubber, characterized in that: The invention comprises the following raw materials in parts by weight: 100 parts of silicone rubber matrix, 30-50 parts of white carbon black, 5-10 parts of hydroxy silicone oil, 1-3 parts of coupling agent, 10-20 parts of ceramic filler, 1-5 parts of vulcanizing agent, 10-30 parts of fluxing agent and 4-8 parts of flame retardant; The ceramic filler comprises the following raw materials in parts by weight: 10-30 parts of coal gasification carbon residue, 20-40 parts of Al2O3, 10-30 parts of Cr2O7, 20-40 parts of TiO2 and 5-15 parts of Li2O; The flame retardant is compounded by ultra-long hydroxyapatite nanowires and ammonium polyphosphate @ chitosan @ Si flame retardant in a mass ratio of 4:1-16; The method for preparing the ammonium polyphosphate @ chitosan @ Si flame retardant is as follows: 100g chitosan is dissolved in a 1wt% acetic acid solution, 1kg ammonium polyphosphate is dispersed in 2L deionized water, and then an acetic acid solution in which CS is dissolved is added, and APP@CS is obtained by centrifugal precipitation and washing; APP@CS is dispersed in 2L deionized water; 10 g of Si-COOH was dissolved in ammonia water and the pH was adjusted to 8, and then added into the mixed solution containing APP@CS. After stirring, washing, centrifuging and drying, ammonium polyphosphate@chitosan@Si flame retardant with carboxylated Si-COOH coated on the surface of APP and CS was obtained. The synthesis method of Si-COOH is as follows: 40g toluene, 20g PMHS and chloroplatinic acid hexahydrate are mixed and heated to 80°C under a nitrogen atmosphere; then 30g MMA is slowly dripped into the solution and heated to 140°C for reaction for 30h. The product is distilled under reduced pressure, washed, and treated, and then 100mL 10% NaOH is added, heated to 100°C, hydrolyzed for 2h and methanol is fractionated, and finally hydrochloric acid is added to the reaction solution to adjust the pH to 6, and the precipitated product is washed with water and dried to obtain Si-COOH.

2. The highly flame retardant ceramic silicone rubber according to claim 1, characterized in that: The silicone rubber matrix is ​​one of methyl vinyl silicone rubber, methyl phenyl vinyl silicone rubber, fluorosilicone rubber and dimethyl silicone rubber.

3. The highly flame retardant ceramic silicone rubber according to claim 1, characterized in that: The vulcanizing agent is 2,4-dichlorobenzoyl peroxide and / or dimethyl-(tert-butylperoxide isopropyl)benzene.

4. The highly flame retardant ceramic silicone rubber according to claim 1, characterized in that: The flux is one or more of glass powder, boron trioxide and zinc borate.

5. The method for preparing a highly flame-retardant ceramic silicone rubber according to any one of claims 1 to 4, characterized in that: The steps are as follows: S1: Add the silicone rubber matrix into the kneader and knead for 3-6 minutes, then add white carbon black and hydroxy silicone oil for mixing; S2: adding coupling agent, ceramic filler, flux and flame retardant to the mixed material after S1 mixing and continuing mixing; S3: vacuum treating the mixed material in S2, and adding a vulcanizing agent to mix the rubber material in an open mill after the rubber material is cooled; S4: The material mixed in S3 is pressed into sheets, heated and vulcanized on a flat vulcanizer, and then vulcanized again in an oven to obtain highly flame-retardant ceramic silicone rubber.

6. The method for preparing the highly flame retardant ceramic silicone rubber according to claim 5, characterized in that: The mixing temperature in S1 is 60-90°C and the mixing time is 20-30 minutes.

7. The method for preparing highly flame-retardant ceramic silicone rubber according to claim 5, characterized in that: The mixing temperature in S2 is 60-90°C and the mixing time is 60-120 min.

8. The method for preparing highly flame-retardant ceramic silicone rubber according to claim 5, characterized in that: The temperature of vacuum treatment in S3 is 90-110°C, the vacuum degree is -0.1~-0.05MPa, and the time of vacuum treatment is 20-30min; the temperature of mixing in S3 is 20-30°C, and the time is 10-20min.

9. The method for preparing highly flame-retardant ceramic silicone rubber according to claim 5, characterized in that: The temperature of the vulcanizer heating vulcanization in S4 is 140-180°C, the time is 20-40min, and the pressure is 10-15MPa; the temperature of the secondary vulcanization is 180-200°C, and the time is 60-180min.