Ethylene-propylene-diene monomer thermal insulation material and preparation method and application thereof

Abstract

The invention discloses an ethylene propylene diene monomer thermal insulation material as well as a preparation method and application thereof, and belongs to the technical field of thermal insulation materials. The ethylene propylene diene monomer thermal insulation material is prepared from the following raw materials: ethylene propylene diene monomer, ablation-resistant fibers, a reinforcing agent, a plasticizer, a flame retardant, zinc oxide, tackifying resin, alkyl phenolic resin, a vulcanizing agent, a coupling agent, an anti-aging agent, stearic acid and an accelerant. The ethylene propylene diene monomer rubber heat insulation material has high strength and excellent scouring resistance, is mainly applied to the field of manufacturing of solid rocket engines in the aerospace field, especially the field of engine heat protection under severe working conditions, has excellent self-adhesion, and can be used as a heat insulation material for the engine. In the forming process of the heat insulation layer of the engine, excellent processing performance is shown, the reliability of a cold patch can be enhanced, the thermal protection forming efficiency of the engine is remarkably improved, and the thermal protection reliability of the rocket engine can be remarkably improved under the condition that the thickness of the heat insulation layer is not increased.

Description

Technical Field

[0001] The invention belongs to the technical field of thermal insulation materials, and in particular relates to an EPDM thermal insulation material and a preparation method and application thereof. Background Art

[0002] Solid rocket engines, as a high-thrust, convenient and efficient propulsion system, have been widely used in the aerospace field. Solid rocket engines are mainly composed of a shell, an insulation system, a liner and a propellant column. When the engine is working, the propellant column will generate a high temperature of 2500~3500℃ and 10 6 ~10 7 In order to prevent the solid rocket engine combustion chamber casing from coming into contact with high-temperature combustion gas and being burned through, or to prevent the casing material from overheating and reducing the casing strength and structural integrity, a thermal insulation system that can adapt to harsh working conditions must be used for thermal protection. The performance of the thermal insulation material is directly related to the success or failure of the space mission.

[0003] As the requirements for solid rocket thrust, total impulse and other indicators continue to increase, the engine propellant needs to adopt a solution with high filling density, high energy, high burning rate and high aluminum powder content. The engine insulation layer is prone to problems such as excessive ablation and decreased thermal insulation performance under long-term high-temperature combustion gas scouring, which affects the safety and reliability of the engine.

[0004] In addition to being resistant to ablation and erosion, the inner insulation layer material of a solid rocket engine also needs to withstand the temperature cycle and temperature shock test during the storage of the solid rocket to prevent debonding and cracking due to thermal stress, which affects the safety of the solid rocket. Currently, the important filler to improve the ablation resistance of the material is short-cut organic fiber, but increasing the amount of such fiber filler will cause the insulation material to have obvious anisotropy, especially the elongation at break parallel to the fiber direction will decrease significantly. Therefore, it is necessary to solve the contradiction between ablation resistance and mechanical anisotropy and develop a new insulation material with excellent comprehensive performance.

[0005] The thermal protection molding of solid rocket engines involves two key factors: one is material performance, and the other is process molding reliability and efficiency. A good process can give full play to the excellent performance of the material and shorten the molding cycle. EPDM rubber-based internal insulation materials usually have poor self-adhesion. When pasting and molding in engines with a thicker insulation layer, it is necessary to use a hot pressing process to stick each layer of material tightly. However, this brings a problem. As the number of hot pressing times increases, the previously pasted material will experience a longer thermal history, which will cause the material itself to start vulcanization prematurely and lose material performance. In addition, there is also a risk of poor bonding between the prematurely vulcanized material and the subsequent raw sheet interface. If cold pressing can be used instead of hot pressing, this risk can be solved, but the self-adhesion of the material needs to be improved. Summary of the invention

[0006] In view of the above-mentioned prior art, the present invention provides an EPDM rubber insulation material and a preparation method and application thereof, so as to solve the problems of poor strength, erosion resistance and self-adhesion of the existing insulation materials.

[0007] In order to achieve the above object, the technical solution adopted by the present invention is to provide an EPDM rubber insulation material, the raw materials for preparation include the following components in parts by weight: 100 parts of EPDM rubber, 10-20 parts of ablation-resistant fiber, 15-35 parts of reinforcing agent, 8-18 parts of plasticizer, 6-28 parts of flame retardant, 0-7 parts of zinc oxide, 6-10 parts of tackifying resin, 8-20 parts of alkyl phenolic resin, 1-5 parts of vulcanizing agent, 0.5-5 parts of coupling agent, 0.5-6 parts of antioxidant and 0-3 parts of stearic acid.

[0008] Based on the above technical solution, the present invention can also be improved as follows.

[0009] Furthermore, the EPDM rubber is EPDM J-4045; the ablation-resistant fiber is aramid fiber and / or aramid sulfone fiber, and the length of the ablation-resistant fiber is 3-6 mm.

[0010] Furthermore, the reinforcing agent is fumed silica.

[0011] Furthermore, the plasticizer is at least one of long-chain alkane oil, cycloalkane oil and paraffin oil.

[0012] Furthermore, the flame retardant is at least one of zinc borate, halogen-antimony flame retardant and ammonium polyphosphate.

[0013] Furthermore, the tackifying resin is a terpene resin and / or a petroleum resin.

[0014] Furthermore, the vulcanizing agent is at least one of dicumyl peroxide, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane and sulfur.

[0015] Furthermore, the coupling agent is at least one of γ-aminopropyltriethoxysilane, bis-[3-(triethoxysilyl)-propyl]tetrasulfide, bis-[3-(triethoxysilyl)-propyl]disulfide and vinyltriethoxysilane; the antioxidant is N-isopropyl-N'-phenyl-p-phenylenediamine or 2,2,4-trimethyl-1,2-dihydroquinoline; and the accelerator is tetramethylthiuram disulfide.

[0016] The present invention also discloses a method for preparing the EPDM rubber thermal insulation material, comprising the following steps: S1: The ablation-resistant fiber is immersed in an ethyl acetate solution of a 1-2wt% KH550 silane coupling agent for activation for 12-16 hours, then washed with ethyl acetate, and then dried at 50°C to obtain a pretreated ablation-resistant fiber; S2: mixing the pretreated ablation-resistant fiber with the EPDM rubber, and then kneading to obtain a mixture; S3: Add reinforcing agent, plasticizer, zinc oxide, stearic acid, coupling agent, alkyl phenolic resin, antioxidant, tackifying resin and flame retardant to the mixed material, mix evenly and pass thinly on an open mill for 20 times; S4: Add the vulcanizing agent to the material after thinning in S3, and continue to thin for 15 times to obtain the base material; S5: vulcanize the base material at 155-170°C and 10MPa for 40 minutes to obtain the product.

[0017] The invention also discloses the application of the EPDM rubber thermal insulation material in preparing the inner thermal insulation layer of a solid rocket engine.

[0018] The beneficial effects of the present invention are: 1. The EPDM rubber insulation material prepared by the present invention has excellent weather resistance and aging resistance: the EPDM rubber used in the present invention is a terpolymer of ethylene, propylene and non-conjugated dienes with a mass fraction of 45% to 55% ethylene and a mass fraction of 5-ethylidene norbornene (ENB) of 5% to 9% (EPDM produced by China Petroleum Jilin Petrochemical Company, with a grade of EPDM J-4045). Due to the specific ratio of ethylene and ENB, the EPDM rubber has excellent weather resistance and aging resistance, and can maintain the stability of its physical and chemical properties for a long time under harsh environments, thereby extending the service life of the material. In addition, the EPDM rubber used has a high elastic modulus and good recovery, and can quickly recover to its original shape after being subjected to external forces, thereby ensuring the stability and reliability of the material during use. At the same time, the copolymerization of ethylene and ENB enables the material to maintain stable performance in a wide temperature range, and can maintain its structural strength at high temperatures and good flexibility at low temperatures, so that it is suitable for applications in various extreme temperature environments. Furthermore, the EPDM rubber has a low melting point and good fluidity, making it easy to be plastic and formed during processing, thereby improving production efficiency and reducing production costs. The EPDM rubber used in the present invention, due to its specific chemical composition, gives the material a series of excellent beneficial effects, making the material have a wide range of application prospects in various fields.

[0019] 2. The present invention enhances the tensile strength and mechanical properties of the material by adding a reinforcing agent to the EPDM rubber. And by adding a plasticizer, not only the elongation at break of the thermal insulation material is improved, but also the overall high temperature resistance of the material is improved and the volatile matter is reduced. The addition of the tackifier effectively improves the bonding performance of the material, significantly improves the self-adhesiveness of the thermal insulation material, and has more superior process performance. The coupling agent used in the present invention can produce a good chemical bonding type between fillers such as fibers and the EPDM matrix, significantly improves the interfacial bonding strength of the material, and thus improves the overall performance of the material. The present invention also adds a flame retardant and an antioxidant to the EPDM rubber. The addition of the flame retardant improves the flame retardant properties of the material and ensures the safe operation of the rocket engine, while the antioxidant can effectively prevent the material from being aged by heat during use. The present invention effectively solves the problem of existing thermal insulation materials in terms of density (less than 1.15g / cm 3 ), ablation resistance (less than 0.08mm / s), tensile strength (greater than 7MPa), elongation at break (greater than 430%), and self-adhesion (greater than 0.1MPa after cold pressing), achieving a significant improvement in the overall performance. DETAILED DESCRIPTION

[0020] The EPDM used in the embodiment of the present invention is purchased from the EPDM produced by China Petroleum Jilin Petrochemical Company, with the brand name EPDM J-4045, and other rubbers with similar performance to the EPDM are also suitable for the present invention. The remaining raw materials are all commercially available materials and can be directly purchased.

[0021] The specific implementation modes of the present invention are described in detail below with reference to the embodiments.

[0022] Example 1 An EPDM rubber thermal insulation material, the raw materials for preparing the material include the following components in parts by weight: 100 parts of EPDM rubber; 20 parts of aramid fiber (ablation-resistant fiber) with a length of about 5 mm; 25 parts of fumed silica (reinforcement agent); 10 parts of paraffin oil (plasticizer); 18 parts of alkyl phenolic resin; 5 parts of zinc oxide; 2 parts of stearic acid; 10 parts of ammonium polyphosphate (flame retardant); 6 parts of terpene resin (tackifying resin); 1.5 parts of bis-[3-(triethoxysilyl)-propyl] disulfide (coupling agent); 1.5 parts of 2,2,4-trimethyl-1,2-dihydroquinoline (anti-aging agent); 2 parts of sulfur (vulcanizing agent); 1.2 parts of tetramethylthiuram disulfide (accelerator).

[0023] The EPDM rubber insulation material in this embodiment is prepared by the following steps: S1: The aramid fiber was immersed in an ethyl acetate solution of KH550 silane coupling agent with a concentration of 1.5wt% for 14 hours for activation, then washed with ethyl acetate, and then dried at 50°C to obtain a pretreated ablation-resistant fiber; S2: mixing the pretreated ablation-resistant fiber with the EPDM rubber, and then kneading the mixture using an open mill to obtain a mixture; S3: Add fumed silica and paraffin oil to the mixture several times; then add zinc oxide, stearic acid, bis-[3-(triethoxysilyl)-propyl] disulfide, alkylphenol resin, 2,2,4-trimethyl-1,2-dihydroquinoline, terpene resin, and ammonium polyphosphate in sequence, mix thoroughly and evenly; then thinly pass on an open mill 20 times; S4: Add sulfur and tetramethylthiuram disulfide to the material after thinning in S3, and continue to thin for 15 times to obtain the base material; S5: The base material is vulcanized and molded at 160° C. and 10 MPa for 40 minutes to obtain the product.

[0024] Example 2 An EPDM rubber thermal insulation material, the raw materials for preparing the material include the following components in parts by weight: 100 parts of EPDM rubber; 20 parts of aramid fiber (ablation-resistant fiber) with a length of about 3 mm; 35 parts of fumed silica (reinforcement agent); 10 parts of paraffin oil (plasticizer); 18 parts of alkyl phenolic resin; 5 parts of zinc oxide; 2 parts of stearic acid; 10 parts of ammonium polyphosphate (flame retardant); 6 parts of terpene resin (tackifying resin); 1.5 parts of bis-[3-(triethoxysilyl)-propyl] disulfide (coupling agent); 1.5 parts of 2,2,4-trimethyl-1,2-dihydroquinoline (anti-aging agent); 2 parts of sulfur (vulcanizing agent); 1.2 parts of tetramethylthiuram disulfide (accelerator).

[0025] The EPDM rubber insulation material in this embodiment is prepared by the following steps: S1: The aramid fiber was immersed in an ethyl acetate solution of KH550 silane coupling agent with a concentration of 1wt% for 16 hours for activation, then washed with ethyl acetate, and then dried at 50°C to obtain a pretreated ablation-resistant fiber; S2: mixing the pretreated ablation-resistant fiber with the EPDM rubber, and then kneading the mixture using an open mill to obtain a mixture; S3: Add fumed silica and paraffin oil to the mixture several times; then add zinc oxide, stearic acid, bis-[3-(triethoxysilyl)-propyl] disulfide, alkylphenol resin, 2,2,4-trimethyl-1,2-dihydroquinoline, terpene resin, and ammonium polyphosphate in sequence, mix thoroughly and evenly; then thinly pass on an open mill 20 times; S4: Add sulfur and tetramethylthiuram disulfide to the material after thinning in S3, and continue to thin for 15 times to obtain the base material; S5: The base material is vulcanized and molded at 155°C and 10MPa for 40 minutes to obtain the product.

[0026] Example 3 An EPDM rubber thermal insulation material, the raw materials for preparing the material include the following components in parts by weight: 100 parts of EPDM rubber; 10 parts of aramid fiber with a length of about 3mm + 10 parts of aromatic sulfone fiber with a length of about 3mm (ablation-resistant fiber); 30 parts of fumed silica (reinforcement agent); 15 parts of paraffin oil (plasticizer); 18 parts of alkyl phenolic resin; 15 parts of decabromodiphenyl ethane + 5 parts of antimony oxide (flame retardant); 5 parts of zinc oxide; 2 parts of stearic acid; 10 parts of petroleum resin (tackifying resin); 1 part of γ-aminopropyltriethoxysilane (coupling agent); 1.5 parts of 2,2,4-trimethyl-1,2-dihydroquinoline (anti-aging agent); 2 parts of diisopropylbenzene oxide (vulcanizing agent).

[0027] The EPDM rubber insulation material in this embodiment is prepared by the following steps: S1: The ablation-resistant fiber is immersed in an ethyl acetate solution of a 2wt% KH550 silane coupling agent for activation for 12 hours, then washed with ethyl acetate, and then dried at 50°C to obtain a pretreated ablation-resistant fiber; S2: mixing the pretreated ablation-resistant fiber with the EPDM rubber, and then kneading the mixture using an open mill to obtain a mixture; S3: Add fumed silica and paraffin oil to the mixture several times; then add zinc oxide, stearic acid, γ-aminopropyl triethoxysilane, alkyl phenolic resin, 2,2,4-trimethyl-1,2-dihydroquinoline, petroleum resin, decabromodiphenylethane and antimony oxide in sequence, mix thoroughly and evenly; then thinly pass through the open mill 20 times; S4: Add diisopropylbenzene oxide to the material after thinning in S3, and continue to thin for 15 times to obtain the base material; S5: The base material is vulcanized and molded at 170°C and 10MPa for 40 minutes to obtain the product.

[0028] Example 4 An EPDM rubber thermal insulation material, the raw materials for preparing the material include the following components in parts by weight: 100 parts of EPDM rubber; 8 parts of aramid fiber with a length of about 6 mm + 8 parts of aromatic sulfone fiber with a length of about 6 mm (ablation-resistant fiber); 30 parts of fumed silica (reinforcement agent); 15 parts of paraffin oil (plasticizer); 20 parts of alkyl phenolic resin; 15 parts of decabromodiphenyl ethane + 5 parts of antimony oxide (flame retardant); 5 parts of zinc oxide; 2 parts of stearic acid; 10 parts of petroleum resin (tackifying resin); 1 part of γ-aminopropyltriethoxysilane (coupling agent); 1.5 parts of 2,2,4-trimethyl-1,2-dihydroquinoline (anti-aging agent); 2 parts of diisopropylbenzene oxide (vulcanizing agent).

[0029] The EPDM rubber insulation material in this embodiment is prepared by the following steps: S1: The ablation-resistant fiber is immersed in an ethyl acetate solution of a 2wt% KH550 silane coupling agent for activation for 16 hours, then washed with ethyl acetate, and then dried at 50°C to obtain a pretreated ablation-resistant fiber; S2: mixing the pretreated ablation-resistant fiber with the EPDM rubber, and then kneading the mixture using an open mill to obtain a mixture; S3: Add fumed silica and paraffin oil to the mixture several times; then add zinc oxide, stearic acid, γ-aminopropyl triethoxysilane, alkyl phenolic resin, 2,2,4-trimethyl-1,2-dihydroquinoline, petroleum resin, decabromodiphenylethane and antimony oxide in sequence, mix thoroughly and evenly; then thinly pass through the open mill 20 times; S4: Add diisopropylbenzene oxide to the material after thinning in S3, and continue to thin for 15 times to obtain the base material; S5: The base material is vulcanized and molded at 160° C. and 10 MPa for 40 minutes to obtain the product.

[0030] Example 5 An EPDM rubber thermal insulation material, the raw materials for preparing the material include the following components in parts by weight: 100 parts of EPDM rubber; 16 parts of aromatic sulfone fiber (ablation-resistant fiber) with a length of about 5 mm; 25 parts of fumed silica (reinforcement agent); 15 parts of paraffin oil (plasticizer); 18 parts of alkyl phenolic resin; 2 parts of stearic acid; 15 parts of ammonium polyphosphate (flame retardant); 6 parts of terpene resin (tackifying resin); 2 parts of γ-aminopropyltriethoxysilane (coupling agent); 1.5 parts of 2,2,4-trimethyl-1,2-dihydroquinoline (anti-aging agent); 2 parts of diisopropyl peroxide (vulcanizing agent).

[0031] The EPDM rubber insulation material in this embodiment is prepared by the following steps: S1: The arylsulfone fiber was immersed in an ethyl acetate solution of KH550 silane coupling agent with a concentration of 2wt% for 14 hours for activation, then washed with ethyl acetate, and then dried at 50°C to obtain a pretreated ablation-resistant fiber; S2: mixing the pretreated ablation-resistant fiber with the EPDM rubber, and then kneading the mixture using an open mill to obtain a mixture; S3: Add fumed silica and paraffin oil to the mixture several times; then add stearic acid, γ-aminopropyltriethoxysilane, alkylphenolic resin, 2,2,4-trimethyl-1,2-dihydroquinoline, terpene resin and ammonium polyphosphate in sequence, mix thoroughly and evenly; then thinly pass on an open mill 20 times; S4: Add dicumyl peroxide to the material after thinning in S3, and continue to thin for 15 times to obtain the base material; S5: The base material is vulcanized and molded at 160° C. and 10 MPa for 40 minutes to obtain the product.

[0032] Example 6 An EPDM rubber thermal insulation material, the raw materials for preparing the material include the following components in parts by weight: 100 parts of EPDM rubber; 20 parts of aromatic sulfone fiber (ablation-resistant fiber) with a length of about 5 mm; 25 parts of fumed silica (reinforcement agent); 15 parts of paraffin oil (plasticizer); 18 parts of alkyl phenolic resin; 2 parts of stearic acid; 15 parts of ammonium polyphosphate (flame retardant); 10 parts of terpene resin (tackifying resin); 2 parts of γ-aminopropyltriethoxysilane (coupling agent); 1.5 parts of 2,2,4-trimethyl-1,2-dihydroquinoline (anti-aging agent); 2 parts of diisopropyl peroxide (vulcanizing agent).

[0033] The EPDM rubber insulation material in this embodiment is prepared by the following steps: S1: The sulfone fiber was immersed in an ethyl acetate solution of KH550 silane coupling agent with a concentration of 2wt% for 16 hours for activation, then washed with ethyl acetate, and then dried at 50°C to obtain a pretreated ablation-resistant fiber; S2: mixing the pretreated ablation-resistant fiber with the EPDM rubber, and then kneading the mixture using an open mill to obtain a mixture; S3: Add fumed silica and paraffin oil to the mixture several times; then add stearic acid, γ-aminopropyltriethoxysilane, alkylphenolic resin, 2,2,4-trimethyl-1,2-dihydroquinoline, terpene resin and ammonium polyphosphate in sequence, mix thoroughly and evenly; then thinly pass on an open mill 20 times; S4: Add dicumyl peroxide to the material after thinning in S3, and continue to thin for 15 times to obtain the base material; S5: The base material is vulcanized and molded at 160° C. and 10 MPa for 40 minutes to obtain the product.

[0034] Comparative Example 1 An EPDM rubber thermal insulation material, the raw materials for preparing the material include the following components in parts by weight: 100 parts of EPDM rubber, 40 parts of carbon black, 20 parts of asbestos fiber, 10 parts of aluminum hydroxide, 5 parts of paraffin oil, 2 parts of bis-(γ-triethoxysilylpropyl) tetrasulfide, 2 parts of zinc oxide, 1 part of N-cyclohexyl-2-benzothiazolylsulfonamide, 3 parts of sulfur, and 10 parts of hollow ceramic microspheres.

[0035] The EPDM rubber insulation material in this comparative example is prepared by the following steps: The components except the hollow ceramic micro-beads are added into an open mixer and kneaded evenly, and then the hollow ceramic micro-beads are added in batches and kneaded evenly to obtain the product.

[0036] Comparative Example 2 An EPDM rubber thermal insulation material, the raw materials for preparing the material include the following components in parts by weight: 100 parts of EPDM rubber, 40 parts of carbon black, 20 parts of asbestos fiber, 10 parts of aluminum hydroxide, 5 parts of paraffin oil, 2 parts of bis-(γ-triethoxysilylpropyl) tetrasulfide, 2 parts of zinc oxide, 1 part of N-cyclohexyl-2-benzothiazolylsulfonamide, 3 parts of sulfur, and 15 parts of hollow ceramic microspheres.

[0037] The EPDM rubber insulation material in this comparative example is prepared by the following steps: The components except the hollow ceramic micro-beads are added into an open mixer and kneaded evenly, and then the hollow ceramic micro-beads are added in batches and kneaded evenly to obtain the product.

[0038] Comparative Example 3 An EPDM rubber thermal insulation material, the raw materials for preparing the material include the following components in parts by weight: 100 parts of EPDM rubber, 40 parts of carbon black, 20 parts of asbestos fiber, 10 parts of aluminum hydroxide, 5 parts of paraffin oil, 2 parts of bis-(γ-triethoxysilylpropyl) tetrasulfide, 2 parts of zinc oxide, 1 part of N-cyclohexyl-2-benzothiazolylsulfonamide, 3 parts of sulfur, and 20 parts of hollow ceramic microspheres.

[0039] The EPDM rubber insulation material in this comparative example is prepared by the following steps: The components except the hollow ceramic micro-beads are added into an open mixer and kneaded evenly, and then the hollow ceramic micro-beads are added in batches and kneaded evenly to obtain the product.

[0040] Comparative Example 4 An EPDM rubber thermal insulation material, the raw materials for preparing the material include the following components in parts by weight: 100 parts of EPDM rubber, 40 parts of carbon black, 20 parts of asbestos fiber, 10 parts of aluminum hydroxide, 5 parts of paraffin oil, 2 parts of bis-(γ-triethoxysilylpropyl) tetrasulfide, 2 parts of zinc oxide, 1 part of N-cyclohexyl-2-benzothiazolylsulfonamide, 3 parts of sulfur, and 25 parts of hollow ceramic microspheres.

[0041] The EPDM rubber insulation material in this comparative example is prepared by the following steps: The components except the hollow ceramic micro-beads are added into an open mixer and kneaded evenly, and then the hollow ceramic micro-beads are added in batches and kneaded evenly to obtain the product.

[0042] Results Analysis The properties of the EPDM rubber insulation materials prepared in the above embodiments and comparative examples were tested. The test methods and test results are shown in Table 1.

[0043] Table 1

[0044] It can be seen from Table 1 that the thermal insulation rubber materials obtained in Examples 1 to 6 have greater tensile strength, smaller oxyacetylene wire ablation rate, higher hardness, and better thermal insulation effect than the thermal insulation rubber materials obtained in Comparative Examples 1 to 4.

[0045] Although the specific implementation of the present invention is described in detail in conjunction with the embodiments, it should not be understood as limiting the scope of protection of this patent. Within the scope described in the claims, various modifications and variations that can be made by those skilled in the art without creative work still fall within the scope of protection of this patent.

Claims

1. An EPDM rubber insulation material, characterized in that: The raw materials for preparation include the following components in parts by weight: 100 parts of EPDM rubber, 10-20 parts of ablation-resistant fiber, 15-35 parts of reinforcing agent, 8-18 parts of plasticizer, 6-28 parts of flame retardant, 0-7 parts of zinc oxide, 6-10 parts of tackifying resin, 8-20 parts of alkyl phenolic resin, 1-5 parts of vulcanizing agent, 0.5-5 parts of coupling agent, 0.5-6 parts of antioxidant, 0-3 parts of stearic acid and 0-2 parts of accelerator.

2. The EPDM rubber thermal insulation material according to claim 1, characterized in that: The ethylene propylene diene monomer rubber is EPDM J-4045; the ablation-resistant fiber is aramid fiber and / or aramid sulfone fiber, and the length of the ablation-resistant fiber is 3-6 mm.

3. The EPDM rubber thermal insulation material according to claim 1, characterized in that: The reinforcing agent is fumed silica.

4. The EPDM rubber thermal insulation material according to claim 1, characterized in that: The plasticizer is at least one of long-chain alkane oil, cycloalkane oil and paraffin oil.

5. The EPDM rubber thermal insulation material according to claim 1, characterized in that: The flame retardant is at least one of zinc borate, halogen-antimony flame retardant and ammonium polyphosphate.

6. The EPDM rubber thermal insulation material according to claim 1, characterized in that: The tackifying resin is terpene resin and / or petroleum resin.

7. The EPDM rubber thermal insulation material according to claim 1, characterized in that: The vulcanizing agent is at least one of dicumyl peroxide, 1,1-di-tert-butylperoxy-3,3,5-trimethylcyclohexane and sulfur.

8. The EPDM rubber thermal insulation material according to claim 1, characterized in that: The coupling agent is at least one of γ-aminopropyltriethoxysilane, bis-[3-(triethoxysilyl)-propyl]tetrasulfide, bis-[3-(triethoxysilyl)-propyl]disulfide and vinyltriethoxysilane; the antioxidant is N-isopropyl-N'-phenyl-p-phenylenediamine or 2,2,4-trimethyl-1,2-dihydroquinoline; and the accelerator is tetramethylthiuram disulfide.

9. The method for preparing the EPDM rubber thermal insulation material according to any one of claims 1 to 8, characterized in that: The following steps are involved: S1: The ablation-resistant fiber is immersed in an ethyl acetate solution of a 1-2wt% KH550 silane coupling agent for activation for 12-16 hours, then washed with ethyl acetate, and then dried at 50°C to obtain a pretreated ablation-resistant fiber; S2: mixing the pretreated ablation-resistant fiber with the EPDM rubber, and then kneading to obtain a mixture; S3: Add reinforcing agent, plasticizer, zinc oxide, stearic acid, coupling agent, alkyl phenolic resin, antioxidant, tackifying resin and flame retardant to the mixed material, mix evenly and pass thinly on an open mill for 20 times; S4: Add the vulcanizing agent to the material after thinning in S3, and continue to thin for 15 times to obtain the base material; S5: vulcanize the base material at 155-170°C and 10MPa for 40 minutes to obtain the product.

10. Use of the EPDM rubber insulation material according to any one of claims 1 to 8 in preparing an inner insulation layer of a solid rocket engine.

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