An oil-resistant sealing non-leaking asbestos gasket material and its preparation method

Abstract

The application relates to the technical field of sealing materials, and particularly discloses an oil-resistant sealing non-leakage asbestos gasket material and a preparation method thereof. The oil-resistant sealing non-leakage asbestos gasket material comprises raw materials, i.e. an oil-resistant elastomer base material, reinforcing fillers, a crosslinking agent, a plasticizer, an anti-aging agent and a penetration inhibitor. The preparation method comprises the following steps: S1, preparing a composite mixing rubber; S2, performing mold pressing vulcanization forming on the composite mixing rubber, demolding after heat preservation and shaping, and obtaining a gasket blank; and S3, performing constant-temperature secondary vulcanization treatment on the gasket blank, trimming the corners after solidification, and obtaining the oil-resistant sealing non-leakage asbestos gasket material. The oil-resistant sealing non-leakage asbestos gasket material prepared by the application has high normal tensile strength, high strength retention rate after heat aging and oil immersion, small hardness fluctuation, excellent size stability, significantly improved aging resistance and oil resistance, and effectively solves the problems of easy penetration and sealing failure of traditional asbestos gasket materials during long-term use.

Description

Technical Field

[0001] This application relates to the field of sealing materials technology, and more specifically, it relates to an oil-resistant, leak-proof asbestos gasket material and its preparation method. Background Technology

[0002] Engines, hydraulic equipment, and various industrial machinery operate under complex conditions of oil immersion and alternating high and low temperatures. As a core component, gaskets directly determine the stability and lifespan of these devices. Currently, the mainstream gaskets on the market are divided into two main categories: ordinary rubber gaskets and traditional asbestos gaskets, both of which have significant technical shortcomings. While traditional asbestos gaskets possess a certain level of mechanical strength and heat resistance, their poor substrate density allows oil to easily penetrate through the fiber gaps after prolonged contact with engine oil, hydraulic oil, and other media, gradually leading to problems such as oil seepage and dripping. Simultaneously, the weak interfacial bonding between asbestos fibers and the elastic matrix makes them prone to delamination and shedding under equipment vibration and alternating pressure, resulting in seal failure and, in severe cases, engine cylinder blowout, posing significant safety hazards. Conventional nitrile rubber and silicone rubber gaskets, while possessing decent elasticity, lack sufficient oil resistance. Prolonged immersion in oil can cause swelling, softening, and cracking. Their aging rate accelerates significantly at high temperatures, leading to rapid elasticity loss and increased permanent compression set, making it difficult to maintain a long-term sealing effect.

[0003] Most existing gasket materials rely solely on the properties of the matrix itself for sealing, without specific modifications to address issues such as oil corrosion and media penetration. They also suffer from limited filler combinations, low interfacial bonding strength, insufficient overall structural density, and weak wear resistance and impermeability. As industrial equipment evolves towards higher pressure, longer lifespan, and lower leakage, existing gasket materials can no longer meet the stringent operating requirements. There is an urgent need to develop an asbestos gasket material that combines oil resistance, high temperature resistance, high elasticity, and long-lasting leak prevention, while simultaneously optimizing the material's manufacturing process to improve its overall performance and stability. Summary of the Invention

[0004] To address the technical problems mentioned in the background section, this application provides an oil-resistant, leak-proof asbestos gasket material and its preparation method.

[0005] In the first aspect, this application provides an oil-resistant, leak-proof asbestos gasket material, employing the following technical solution: An oil-resistant, leak-proof asbestos gasket material comprises the following raw materials in parts by weight: 45-65 parts of oil-resistant elastomer substrate, 20-35 parts of reinforcing filler, 2-5 parts of crosslinking agent, 1-3 parts of plasticizer, 1-2 parts of anti-aging agent, and 3-5 parts of penetration inhibitor.

[0006] Preferably, the method for preparing the oil-resistant elastomer substrate includes the following preparation steps: Step 1: Put the raw fluororubber into a two-roll mill for plasticizing to obtain plasticized fluororubber compound; Step 2: Transfer the plasticized fluororubber compound into an internal mixer, add the initiator and graft monomer, and carry out a constant temperature internal mixing reaction to obtain grafted modified fluororubber. Step 3: Add the first blended elastomer and the second blended elastomer to the grafted modified fluororubber in sequence, continue to mix, and after the mixing is completed, cool to room temperature and discharge to obtain the oil-resistant elastomer substrate.

[0007] Preferably, the fluororubber raw material in step 1 is a polyvinylidene fluoride-hexafluoropropylene copolymer and / or a tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer.

[0008] Preferably, the number average molecular weight of the fluororubber raw rubber in step 1 is 80,000-120,000.

[0009] Preferably, in step 1, the plasticizing temperature is 60-80℃, the plasticizing time is 8-15min, the gap between the open mill rolls is controlled at 1-3mm, and the roll speed ratio is 1:1.2-1.5.

[0010] Preferably, in step 2, the mass ratio of plasticized fluororubber compound, initiator and grafted monomer is 100:0.8-1.5:8-12.

[0011] Preferably, the initiator is dicumyl peroxide.

[0012] Preferably, in step 2, the grafting monomer is composed of perfluorooctyl ethyl acrylate, methyl methacrylate and hydroxyethyl acrylate in a mass ratio of 5-8:3-5:1-3.

[0013] Preferably, the constant temperature mixing reaction temperature in step 2 is 125-140℃, and the time is 10-20 min.

[0014] Preferably, in step 3, the mass ratio of the grafted modified fluororubber, the first blended elastomer, and the second blended elastomer is 100:15-25:10-18.

[0015] Preferably, in step 3, the first blended elastomer is nitrile rubber with an acrylonitrile content of 33-38%.

[0016] Preferably, the second blended elastomer in step 3 is perfluorosilicone rubber with a hardness of 40-50 HA.

[0017] Preferably, the mixing temperature in step 3 is 70-90℃ and the mixing time is 15-25min.

[0018] Preferably, the reinforcing filler is composed of asbestos fibers, nano-silica, and talc in a mass ratio of 5-8:3-5:2-3.

[0019] Preferably, the crosslinking agent is triallyl cyanurate.

[0020] Preferably, the plasticizer is diisooctyl phthalate.

[0021] Preferably, the anti-aging agent is composed of antioxidant 1010 and ultraviolet absorber UV-531 in a mass ratio of 1-3:1-2.

[0022] Preferably, the penetration inhibitor is one of organomontmorillonite, paraffin powder, or polytetrafluoroethylene powder.

[0023] Secondly, this application provides a method for preparing an oil-resistant, leak-proof asbestos gasket material, using the following technical solution: A method for preparing an oil-resistant, leak-proof asbestos gasket material includes the following preparation steps: S1. The oil-resistant elastomer base material, reinforcing filler, crosslinking agent, plasticizer, anti-aging agent and penetration inhibitor are put into a mixer, mixed evenly, and after vacuum degassing, a composite compound is obtained. S2. The composite rubber compound is molded and vulcanized, and after heat preservation and shaping, it is demolded to obtain the gasket blank. S3. The gasket blank is subjected to constant temperature secondary vulcanization treatment. After curing, the edges and corners are trimmed to obtain oil-resistant, sealing, and leak-proof asbestos gasket material.

[0024] Preferably, in step S1, the mixing temperature is 80-100℃, the rotation speed is 35-55rpm, and the mixing time is 18-28min.

[0025] Preferably, in step S2, the molding and vulcanization temperature is 120-135℃, the vulcanization pressure is 10-12MPa, and the vulcanization time is 8-12min.

[0026] Preferably, in step S3, the constant temperature secondary vulcanization treatment has a vulcanization temperature of 150-165℃ and a vulcanization time of 2.5-3h.

[0027] In summary, this application has the following beneficial effects: This application optimizes the preparation process of oil-resistant elastomer substrates, precisely controls the blending ratio of fluororubber matrix graft modification system and dual elastomers, and combines it with a suitable mixing and vulcanization molding process. It optimizes the material system from multiple dimensions, including matrix molecular structure, interfacial bonding strength and overall density, which greatly improves the defects of traditional asbestos gasket materials such as poor mechanical properties, weak oil resistance and easy leakage. The prepared asbestos gasket material has excellent mechanical strength, thermal aging stability, oil corrosion resistance and sealing and seepage prevention capabilities, and can be used for a long time in harsh industrial conditions such as high temperature and oil immersion.

[0028] This application achieves precise grafting modification of fluororubber through a compound grafting monomer system. It employs a ternary monomer system of perfluorooctyl ethyl acrylate, methyl methacrylate, and hydroxyethyl acrylate, which are synergistically grafted onto the fluororubber molecular chain. Perfluorooctyl ethyl acrylate imparts excellent oil and hydrophobic properties to the matrix, methyl methacrylate enhances molecular chain rigidity and structural stability, and hydroxyethyl acrylate strengthens the interfacial bonding between the matrix and the filler. This effectively overcomes the drawbacks of single grafting monomers, which result in limited modification functions and numerous molecular structural defects, thereby improving the oil resistance and anti-aging properties of the substrate at the molecular level. The application also utilizes nitrile rubber and... The gasket material is modified by blending a compound of perfluorosilicone rubber and a dual elastomer. Nitrile rubber can improve the toughness and tensile properties of the substrate, while perfluorosilicone rubber can enhance the substrate's resistance to high and low temperatures and its resistance to oil penetration. At the same time, the gradient-optimized mixing, vacuum degassing and secondary vulcanization process can eliminate the internal pores and internal stress of the substrate, allowing the elastomer, filler and additives to form a dense cross-linked whole structure. Ultimately, the normal tensile strength of the gasket material is significantly improved, and the mechanical properties are well retained after high-temperature aging and oil immersion corrosion, with small hardness fluctuation. This effectively improves the leakage problem of traditional gasket materials, achieves long-term sealing under harsh working conditions, and significantly extends the service life of the product. Detailed Implementation

[0029] The present application will be further described in detail below with reference to the embodiments.

[0030] The asbestos fiber used in the embodiments and comparative examples of this application was purchased from Zhengzhou Shengshi Jinding Thermal Insulation and Refractory Materials Co., Ltd.; nano-silica was purchased from Lingshou Ruojia Mineral Products Co., Ltd.; talc powder was purchased from Hebei Huihao Environmental Protection Technology Co., Ltd.; organomontmorillonite was purchased from Lingshou Yongshun Mineral Products Processing Plant; paraffin powder was purchased from Shanghai Kaiyin Chemical Co., Ltd.; polytetrafluoroethylene powder was purchased from Dongguan Shengli New Materials Co., Ltd.; and polyvinylidene fluoride-hexafluoropropylene copolymer (item number: lnb-1003) was purchased from Wuhan Lanabai Pharmaceutical Chemical Co., Ltd. The following materials were purchased from Dongguan Caihua Plastics Technology Co., Ltd.: tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer (brand name: FKM246G); perfluorooctyl ethyl acrylate from Tesco Chemical (Hubei) Co., Ltd.; methyl methacrylate from Jinan Anqi Chemical Co., Ltd.; hydroxyethyl acrylate from Jinan Yuansheng Chemical Co., Ltd.; nitrile rubber (acrylonitrile content: 33%) from Dongguan Jiaqing Plastic Raw Materials Co., Ltd.; and perfluorosilicone rubber (hardness: 40HA) from Nanjing Haideman Rubber & Plastics Co., Ltd.

[0031] Examples 1-3 provide an oil-resistant, leak-proof asbestos gasket material and its preparation method.

[0032] Example 1 An oil-resistant, leak-proof asbestos gasket material comprises the following raw materials in parts by weight: 45 parts of oil-resistant elastomer substrate, 20 parts of reinforcing filler, 2 parts of crosslinking agent, 1 part of plasticizer, 1 part of anti-aging agent, and 3 parts of penetration inhibitor. The reinforcing filler is composed of asbestos fiber, nano-silica, and talc in a mass ratio of 5:3:2. The crosslinking agent is triallyl cyanurate, the plasticizer is diisooctyl phthalate, the anti-aging agent is composed of antioxidant 1010 and ultraviolet absorber UV-531 in a mass ratio of 1:1, and the penetration inhibitor is organomontmorillonite.

[0033] The preparation method of the oil-resistant elastomer substrate includes the following preparation steps: Step 1: Put the polyvinylidene fluoride-hexafluoropropylene copolymer into a two-roll mill for plasticizing. The plasticizing temperature is 60℃, the plasticizing time is 8min, the roller gap of the two-roll mill is controlled at 1mm, and the roller speed ratio is 1:1.2 to obtain the plasticized fluororubber compound. Step 2: Transfer the plasticized fluororubber compound into a mixer, add dicumyl peroxide and graft monomers, and carry out a constant temperature mixing reaction. The constant temperature mixing reaction temperature is 125℃, the time is 10min, and the mixing speed is 40rpm to obtain grafted modified fluororubber. The mass ratio of plasticized fluororubber compound, dicumyl peroxide and graft monomers is 100:0.8:8. The graft monomers are composed of perfluorooctyl ethyl acrylate, methyl methacrylate and hydroxyethyl acrylate in a mass ratio of 5:3:1. Step 3: Add the first blended elastomer and the second blended elastomer to the grafted modified fluororubber in sequence, and continue to mix. The mixing temperature is 70℃, the mixing time is 15min, and the mixing speed is 30rpm. After mixing, cool to room temperature and discharge to obtain an oil-resistant elastomer substrate. The mass ratio of the grafted modified fluororubber, the first blended elastomer, and the second blended elastomer is 100:15:10. The first blended elastomer is nitrile rubber, and the second blended elastomer is perfluorosilicone rubber.

[0034] A method for preparing an oil-resistant, leak-proof asbestos gasket material includes the following preparation steps: S1. The oil-resistant elastomer base material, reinforcing filler, crosslinking agent, plasticizer, anti-aging agent and penetration inhibitor are put into the internal mixer and mixed. The temperature is controlled at 80℃, the speed is 35rpm, the mixing time is 18min, and after the mixture is uniform, vacuum degassing is performed. The vacuum degree is -0.07MPa and the degassing time is 3min. After vacuum degassing, the composite compound is obtained. S2. The composite compound rubber is molded and vulcanized. The molding and vulcanization temperature is 120℃, the vulcanization pressure is 10MPa, the vulcanization time is 8min, and after heat preservation and shaping, it is demolded to obtain the gasket blank. S3. The gasket blank is subjected to constant temperature secondary vulcanization treatment at a temperature of 150℃ for 2.5 hours. After curing, the edges and corners are trimmed to obtain an oil-resistant, sealing, and leak-proof asbestos gasket material.

[0035] Example 2 An oil-resistant, leak-proof asbestos gasket material comprises the following raw materials in parts by weight: 55 parts of oil-resistant elastomer base material, 28 parts of reinforcing filler, 4 parts of crosslinking agent, 2 parts of plasticizer, 1.5 parts of anti-aging agent, and 4 parts of penetration inhibitor. The reinforcing filler is composed of asbestos fiber, nano-silica, and talc in a mass ratio of 7:4:2.5. The crosslinking agent is triallyl cyanurate, the plasticizer is diisooctyl phthalate, the anti-aging agent is composed of antioxidant 1010 and ultraviolet absorber UV-531 in a mass ratio of 2:1.5, and the penetration inhibitor is paraffin powder.

[0036] The preparation method of the oil-resistant elastomer substrate includes the following preparation steps: Step 1: Put the tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer into a two-roll mill for plasticizing. The plasticizing temperature is 70℃, the plasticizing time is 12min, the roller gap of the two-roll mill is controlled at 2mm, and the roller speed ratio is 1:1.4 to obtain the plasticized fluororubber compound. Step 2: Transfer the plasticized fluororubber compound into a mixer, add dicumyl peroxide and graft monomers, and carry out a constant temperature mixing reaction. The constant temperature mixing reaction temperature is 135℃, the time is 15min, and the mixing speed is 50rpm to obtain grafted modified fluororubber. The mass ratio of plasticized fluororubber compound, dicumyl peroxide and graft monomers is 100:1.2:10. The graft monomers are composed of perfluorooctyl ethyl acrylate, methyl methacrylate and hydroxyethyl acrylate in a mass ratio of 7:4:2. Step 3: Add the first blended elastomer and the second blended elastomer to the grafted modified fluororubber in sequence, and continue to mix. The mixing temperature is 80℃, the mixing time is 20min, and the mixing speed is 45rpm. After mixing, cool to room temperature and discharge to obtain an oil-resistant elastomer substrate. The mass ratio of the grafted modified fluororubber, the first blended elastomer, and the second blended elastomer is 100:20:14. The first blended elastomer is nitrile rubber, and the second blended elastomer is perfluorosilicone rubber.

[0037] A method for preparing an oil-resistant, leak-proof asbestos gasket material includes the following preparation steps: S1. The oil-resistant elastomer base material, reinforcing filler, crosslinking agent, plasticizer, anti-aging agent and penetration inhibitor are put into the internal mixer and mixed. The temperature is controlled at 90℃, the speed is 45rpm, and the mixing time is 23min. After the mixture is uniform, vacuum degassing is performed. The vacuum degree is -0.08MPa and the degassing time is 4.5min. After vacuum degassing, the composite compound is obtained. S2. The composite compound rubber is molded and vulcanized. The molding and vulcanization temperature is 128℃, the vulcanization pressure is 11MPa, the vulcanization time is 10min, and after heat preservation and shaping, it is demolded to obtain the gasket blank. S3. The gasket blank is subjected to constant temperature secondary vulcanization treatment at a temperature of 158℃ for 2.8 hours. After curing, the edges and corners are trimmed to obtain an oil-resistant, sealing, and leak-proof asbestos gasket material.

[0038] Example 3 An oil-resistant, leak-proof asbestos gasket material comprises the following raw materials in parts by weight: 65 parts of oil-resistant elastomer base material, 35 parts of reinforcing filler, 5 parts of crosslinking agent, 3 parts of plasticizer, 2 parts of anti-aging agent, and 5 parts of penetration inhibitor. The reinforcing filler is composed of asbestos fiber, nano-silica, and talc in a mass ratio of 8:5:3. The crosslinking agent is triallyl cyanurate, the plasticizer is diisooctyl phthalate, the anti-aging agent is composed of antioxidant 1010 and ultraviolet absorber UV-531 in a mass ratio of 3:2, and the penetration inhibitor is polytetrafluoroethylene micropowder.

[0039] The preparation method of the oil-resistant elastomer substrate includes the following preparation steps: Step 1: Mix polyvinylidene fluoride-hexafluoropropylene copolymer and tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer at a mass ratio of 1:1, and put them into a two-roll mill for plasticizing. The plasticizing temperature is 80℃, the plasticizing time is 15min, the roller gap of the two-roll mill is controlled at 3mm, and the roller speed ratio is 1:1.5 to obtain plasticized fluororubber compound. Step 2: Transfer the plasticized fluororubber compound into a mixer, add dicumyl peroxide and graft monomers, and carry out a constant temperature mixing reaction. The constant temperature mixing reaction temperature is 140℃, the time is 20min, and the mixing speed is 60rpm to obtain grafted modified fluororubber. The mass ratio of plasticized fluororubber compound, dicumyl peroxide and graft monomers is 100:1.5:12. The graft monomers are composed of perfluorooctyl ethyl acrylate, methyl methacrylate and hydroxyethyl acrylate in a mass ratio of 8:5:3. Step 3: Add the first blended elastomer and the second blended elastomer to the grafted modified fluororubber in sequence, and continue to mix. The mixing temperature is 90℃, the mixing time is 25min, and the mixing speed is 60rpm. After mixing, cool to room temperature and discharge to obtain an oil-resistant elastomer substrate. The mass ratio of the grafted modified fluororubber, the first blended elastomer, and the second blended elastomer is 100:25:18. The first blended elastomer is nitrile rubber, and the second blended elastomer is perfluorosilicone rubber.

[0040] A method for preparing an oil-resistant, leak-proof asbestos gasket material includes the following preparation steps: S1. The oil-resistant elastomer base material, reinforcing filler, crosslinking agent, plasticizer, anti-aging agent and penetration inhibitor are put into the internal mixer and mixed. The temperature is controlled at 100℃, the speed is 55rpm, the mixing time is 28min, and after the mixture is uniform, vacuum degassing is performed. The vacuum degree is -0.09MPa and the degassing time is 6min. After vacuum degassing, the composite compound is obtained. S2. The composite compound rubber is molded and vulcanized. The molding and vulcanization temperature is 135℃, the vulcanization pressure is 12MPa, and the vulcanization time is 12min. After heat preservation and shaping, it is demolded to obtain the gasket blank. S3. The gasket blank is subjected to constant temperature secondary vulcanization treatment at a temperature of 165℃ for 3 hours. After curing, the edges and corners are trimmed to obtain an oil-resistant, sealing, and leak-proof asbestos gasket material.

[0041] Comparative Example 1 An oil-resistant, leak-proof asbestos gasket material comprises the following raw materials in parts by weight: 45 parts of oil-resistant elastomer substrate, 20 parts of reinforcing filler, 2 parts of crosslinking agent, 1 part of plasticizer, 1 part of anti-aging agent, and 3 parts of penetration inhibitor. The reinforcing filler is composed of asbestos fiber, nano-silica, and talc in a mass ratio of 5:3:2. The crosslinking agent is triallyl cyanurate, the plasticizer is diisooctyl phthalate, the anti-aging agent is composed of antioxidant 1010 and ultraviolet absorber UV-531 in a mass ratio of 1:1, and the penetration inhibitor is organomontmorillonite.

[0042] The preparation method of the oil-resistant elastomer substrate includes the following preparation steps: Step 1: Put the polyvinylidene fluoride-hexafluoropropylene copolymer into a two-roll mill for plasticizing. The plasticizing temperature is 60℃, the plasticizing time is 8min, the roller gap of the two-roll mill is controlled at 1mm, and the roller speed ratio is 1:1.2 to obtain the plasticized fluororubber compound. Step 2: Transfer the plasticized fluororubber compound into a mixer, add dicumyl peroxide and graft monomer, and carry out a constant temperature mixing reaction. The constant temperature mixing reaction temperature is 125℃, the time is 10min, and the mixing speed is 40rpm to obtain grafted modified fluororubber. The mass ratio of plasticized fluororubber compound, dicumyl peroxide and graft monomer is 100:0.8:8. The graft monomer is composed of methyl methacrylate and hydroxyethyl acrylate in a mass ratio of 3:1. Step 3: Add the first blended elastomer and the second blended elastomer to the grafted modified fluororubber in sequence, and continue to mix. The mixing temperature is 70℃, the mixing time is 15min, and the mixing speed is 30rpm. After mixing, cool to room temperature and discharge to obtain an oil-resistant elastomer substrate. The mass ratio of the grafted modified fluororubber, the first blended elastomer, and the second blended elastomer is 100:15:10. The first blended elastomer is nitrile rubber, and the second blended elastomer is perfluorosilicone rubber.

[0043] A method for preparing an oil-resistant, leak-proof asbestos gasket material includes the following preparation steps: S1. The oil-resistant elastomer base material, reinforcing filler, crosslinking agent, plasticizer, anti-aging agent and penetration inhibitor are put into the internal mixer and mixed. The temperature is controlled at 80℃, the speed is 35rpm, the mixing time is 18min, and after the mixture is uniform, vacuum degassing is performed. The vacuum degree is -0.07MPa and the degassing time is 3min. After vacuum degassing, the composite compound is obtained. S2. The composite compound rubber is molded and vulcanized. The molding and vulcanization temperature is 120℃, the vulcanization pressure is 10MPa, the vulcanization time is 8min, and after heat preservation and shaping, it is demolded to obtain the gasket blank. S3. The gasket blank is subjected to constant temperature secondary vulcanization treatment at a temperature of 150℃ for 2.5 hours. After curing, the edges and corners are trimmed to obtain an oil-resistant, sealing, and leak-proof asbestos gasket material.

[0044] Comparative Example 2 An oil-resistant, leak-proof asbestos gasket material comprises the following raw materials in parts by weight: 45 parts of oil-resistant elastomer substrate, 20 parts of reinforcing filler, 2 parts of crosslinking agent, 1 part of plasticizer, 1 part of anti-aging agent, and 3 parts of penetration inhibitor. The reinforcing filler is composed of asbestos fiber, nano-silica, and talc in a mass ratio of 5:3:2. The crosslinking agent is triallyl cyanurate, the plasticizer is diisooctyl phthalate, the anti-aging agent is composed of antioxidant 1010 and ultraviolet absorber UV-531 in a mass ratio of 1:1, and the penetration inhibitor is organomontmorillonite.

[0045] The preparation method of the oil-resistant elastomer substrate includes the following preparation steps: Step 1: Put the polyvinylidene fluoride-hexafluoropropylene copolymer into a two-roll mill for plasticizing. The plasticizing temperature is 60℃, the plasticizing time is 8min, the roller gap of the two-roll mill is controlled at 1mm, and the roller speed ratio is 1:1.2 to obtain the plasticized fluororubber compound. Step 2: Transfer the plasticized fluororubber compound into a mixer, add dicumyl peroxide and graft monomer, and carry out a constant temperature mixing reaction. The constant temperature mixing reaction temperature is 125℃, the time is 10min, and the mixing speed is 40rpm to obtain grafted modified fluororubber. The mass ratio of plasticized fluororubber compound, dicumyl peroxide and graft monomer is 100:0.8:8. The graft monomer is composed of perfluorooctyl ethyl acrylate and hydroxyethyl acrylate in a mass ratio of 5:1. Step 3: Add the first blended elastomer and the second blended elastomer to the grafted modified fluororubber in sequence, and continue to mix. The mixing temperature is 70℃, the mixing time is 15min, and the mixing speed is 30rpm. After mixing, cool to room temperature and discharge to obtain an oil-resistant elastomer substrate. The mass ratio of the grafted modified fluororubber, the first blended elastomer, and the second blended elastomer is 100:15:10. The first blended elastomer is nitrile rubber, and the second blended elastomer is perfluorosilicone rubber.

[0046] A method for preparing an oil-resistant, leak-proof asbestos gasket material includes the following preparation steps: S1. The oil-resistant elastomer base material, reinforcing filler, crosslinking agent, plasticizer, anti-aging agent and penetration inhibitor are put into the internal mixer and mixed. The temperature is controlled at 80℃, the speed is 35rpm, the mixing time is 18min, and after the mixture is uniform, vacuum degassing is performed. The vacuum degree is -0.07MPa and the degassing time is 3min. After vacuum degassing, the composite compound is obtained. S2. The composite compound rubber is molded and vulcanized. The molding and vulcanization temperature is 120℃, the vulcanization pressure is 10MPa, the vulcanization time is 8min, and after heat preservation and shaping, it is demolded to obtain the gasket blank. S3. The gasket blank is subjected to constant temperature secondary vulcanization treatment at a temperature of 150℃ for 2.5 hours. After full curing, the edges and corners are trimmed to obtain an oil-resistant, sealing, and leak-proof asbestos gasket material.

[0047] Comparative Example 3 An oil-resistant, leak-proof asbestos gasket material comprises the following raw materials in parts by weight: 45 parts of oil-resistant elastomer substrate, 20 parts of reinforcing filler, 2 parts of crosslinking agent, 1 part of plasticizer, 1 part of anti-aging agent, and 3 parts of penetration inhibitor. The reinforcing filler is composed of asbestos fiber, nano-silica, and talc in a mass ratio of 5:3:2. The crosslinking agent is triallyl cyanurate, the plasticizer is diisooctyl phthalate, the anti-aging agent is composed of antioxidant 1010 and ultraviolet absorber UV-531 in a mass ratio of 1:1, and the penetration inhibitor is organomontmorillonite.

[0048] The preparation method of the oil-resistant elastomer substrate includes the following preparation steps: Step 1: Put the polyvinylidene fluoride-hexafluoropropylene copolymer into a two-roll mill for plasticizing. The plasticizing temperature is 60℃, the plasticizing time is 8min, the roller gap of the two-roll mill is controlled at 1mm, and the roller speed ratio is 1:1.2 to obtain the plasticized fluororubber compound. Step 2: Transfer the plasticized fluororubber compound into a mixer, add dicumyl peroxide and graft monomer, and carry out a constant temperature mixing reaction. The constant temperature mixing reaction temperature is 125℃, the time is 10min, and the mixing speed is 40rpm to obtain grafted modified fluororubber. The mass ratio of plasticized fluororubber compound, dicumyl peroxide and graft monomer is 100:0.8:8. The graft monomer is composed of perfluorooctyl ethyl acrylate and methyl methacrylate in a mass ratio of 5:3. Step 3: Add the first blended elastomer and the second blended elastomer to the grafted modified fluororubber in sequence, and continue to mix. The mixing temperature is 70℃, the mixing time is 15min, and the mixing speed is 30rpm. After mixing, cool to room temperature and discharge to obtain an oil-resistant elastomer substrate. The mass ratio of the grafted modified fluororubber, the first blended elastomer, and the second blended elastomer is 100:15:10. The first blended elastomer is nitrile rubber, and the second blended elastomer is perfluorosilicone rubber.

[0049] A method for preparing an oil-resistant, leak-proof asbestos gasket material includes the following preparation steps: S1. The oil-resistant elastomer base material, reinforcing filler, crosslinking agent, plasticizer, anti-aging agent and penetration inhibitor are put into the internal mixer and mixed. The temperature is controlled at 80℃, the speed is 35rpm, the mixing time is 18min, and after the mixture is uniform, vacuum degassing is performed. The vacuum degree is -0.07MPa and the degassing time is 3min. After vacuum degassing, the composite compound is obtained. S2. The composite compound rubber is molded and vulcanized. The molding and vulcanization temperature is 120℃, the vulcanization pressure is 10MPa, the vulcanization time is 8min, and after heat preservation and shaping, it is demolded to obtain the gasket blank. S3. The gasket blank is subjected to constant temperature secondary vulcanization treatment at a temperature of 150℃ for 2.5 hours. After curing, the edges and corners are trimmed to obtain an oil-resistant, sealing, and leak-proof asbestos gasket material.

[0050] Comparative Example 4 An oil-resistant, leak-proof asbestos gasket material comprises the following raw materials in parts by weight: 45 parts of oil-resistant elastomer substrate, 20 parts of reinforcing filler, 2 parts of crosslinking agent, 1 part of plasticizer, 1 part of anti-aging agent, and 3 parts of penetration inhibitor. The reinforcing filler is composed of asbestos fiber, nano-silica, and talc in a mass ratio of 5:3:2. The crosslinking agent is triallyl cyanurate, the plasticizer is diisooctyl phthalate, the anti-aging agent is composed of antioxidant 1010 and ultraviolet absorber UV-531 in a mass ratio of 1:1, and the penetration inhibitor is organomontmorillonite.

[0051] The preparation method of the oil-resistant elastomer substrate includes the following preparation steps: Step 1: Put the polyvinylidene fluoride-hexafluoropropylene copolymer into a two-roll mill for plasticizing. The plasticizing temperature is 60℃, the plasticizing time is 8min, the roller gap of the two-roll mill is controlled at 1mm, and the roller speed ratio is 1:1.2 to obtain the plasticized fluororubber compound. Step 2: Transfer the plasticized fluororubber compound into a Banbury mixer for constant-temperature mixing reaction at 125℃ for 10 minutes at a speed of 40 rpm. Then, add the first and second blended elastomers sequentially and continue mixing at 70℃ for 15 minutes at a speed of 30 rpm. After mixing, cool to room temperature and discharge to obtain an oil-resistant elastomer base material. The mass ratio of the plasticized fluororubber compound, the first blended elastomer, and the second blended elastomer is 100:15:10. The first blended elastomer is nitrile rubber, and the second blended elastomer is perfluorosilicone rubber.

[0052] A method for preparing an oil-resistant, leak-proof asbestos gasket material includes the following preparation steps: S1. The oil-resistant elastomer base material, reinforcing filler, crosslinking agent, plasticizer, anti-aging agent and penetration inhibitor are put into the internal mixer and mixed. The temperature is controlled at 80℃, the speed is 35rpm, the mixing time is 18min, and after the mixture is uniform, vacuum degassing is performed. The vacuum degree is -0.07MPa and the degassing time is 3min. After vacuum degassing, the composite compound is obtained. S2. The composite compound rubber is molded and vulcanized. The molding and vulcanization temperature is 120℃, the vulcanization pressure is 10MPa, the vulcanization time is 8min, and after heat preservation and shaping, it is demolded to obtain the gasket blank. S3. The gasket blank is subjected to constant temperature secondary vulcanization treatment at a temperature of 150℃ for 2.5 hours. After curing, the edges and corners are trimmed to obtain an oil-resistant, sealing, and leak-proof asbestos gasket material.

[0053] Comparative Example 5 An oil-resistant, leak-proof asbestos gasket material comprises the following raw materials in parts by weight: 45 parts of oil-resistant elastomer substrate, 20 parts of reinforcing filler, 2 parts of crosslinking agent, 1 part of plasticizer, 1 part of anti-aging agent, and 3 parts of penetration inhibitor. The reinforcing filler is composed of asbestos fiber, nano-silica, and talc in a mass ratio of 5:3:2. The crosslinking agent is triallyl cyanurate, the plasticizer is diisooctyl phthalate, the anti-aging agent is composed of antioxidant 1010 and ultraviolet absorber UV-531 in a mass ratio of 1:1, and the penetration inhibitor is organomontmorillonite.

[0054] The preparation method of the oil-resistant elastomer substrate includes the following preparation steps: Step 1: Put the polyvinylidene fluoride-hexafluoropropylene copolymer into a two-roll mill for plasticizing. The plasticizing temperature is 60℃, the plasticizing time is 8min, the roller gap of the two-roll mill is controlled at 1mm, and the roller speed ratio is 1:1.2 to obtain the plasticized fluororubber compound. Step 2: Transfer the plasticized fluororubber compound into a mixer, add dicumyl peroxide and graft monomers, and carry out a constant temperature mixing reaction. The constant temperature mixing reaction temperature is 125℃, the time is 10min, and the mixing speed is 40rpm to obtain grafted modified fluororubber. The mass ratio of plasticized fluororubber compound, dicumyl peroxide and graft monomers is 100:0.8:8. The graft monomers are composed of perfluorooctyl ethyl acrylate, methyl methacrylate and hydroxyethyl acrylate in a mass ratio of 5:3:1. Step 3: Add the blended elastomer to the grafted modified fluororubber and continue mixing. The mixing temperature is 70℃, the mixing time is 15min, and the mixing speed is 30rpm. After mixing, cool to room temperature and discharge to obtain an oil-resistant elastomer substrate. The mass ratio of the grafted modified fluororubber to the blended elastomer is 100:25, and the blended elastomer is nitrile rubber.

[0055] A method for preparing an oil-resistant, leak-proof asbestos gasket material includes the following preparation steps: S1. The oil-resistant elastomer base material, reinforcing filler, crosslinking agent, plasticizer, anti-aging agent and penetration inhibitor are put into the internal mixer and mixed. The temperature is controlled at 80℃, the speed is 35rpm, the mixing time is 18min, and after the mixture is uniform, vacuum degassing is performed. The vacuum degree is -0.07MPa and the degassing time is 3min. After vacuum degassing, the composite compound is obtained. S2. The composite compound rubber is molded and vulcanized. The molding and vulcanization temperature is 120℃, the vulcanization pressure is 10MPa, the vulcanization time is 8min, and after heat preservation and shaping, it is demolded to obtain the gasket blank. S3. The gasket blank is subjected to constant temperature secondary vulcanization treatment at a temperature of 150℃ for 2.5 hours. After curing, the edges and corners are trimmed to obtain an oil-resistant, sealing, and leak-proof asbestos gasket material.

[0056] Comparative Example 6 An oil-resistant, leak-proof asbestos gasket material comprises the following raw materials in parts by weight: 45 parts of oil-resistant elastomer substrate, 20 parts of reinforcing filler, 2 parts of crosslinking agent, 1 part of plasticizer, 1 part of anti-aging agent, and 3 parts of penetration inhibitor. The reinforcing filler is composed of asbestos fiber, nano-silica, and talc in a mass ratio of 5:3:2. The crosslinking agent is triallyl cyanurate, the plasticizer is diisooctyl phthalate, the anti-aging agent is composed of antioxidant 1010 and ultraviolet absorber UV-531 in a mass ratio of 1:1, and the penetration inhibitor is organomontmorillonite.

[0057] The preparation method of the oil-resistant elastomer substrate includes the following preparation steps: Step 1: Put the polyvinylidene fluoride-hexafluoropropylene copolymer into a two-roll mill for plasticizing. The plasticizing temperature is 60℃, the plasticizing time is 8min, the roller gap of the two-roll mill is controlled at 1mm, and the roller speed ratio is 1:1.2 to obtain the plasticized fluororubber compound. Step 2: Transfer the plasticized fluororubber compound into a mixer, add dicumyl peroxide and graft monomers, and carry out a constant temperature mixing reaction. The constant temperature mixing reaction temperature is 125℃, the time is 10min, and the mixing speed is 40rpm to obtain grafted modified fluororubber. The mass ratio of plasticized fluororubber compound, dicumyl peroxide and graft monomers is 100:0.8:8. The graft monomers are composed of perfluorooctyl ethyl acrylate, methyl methacrylate and hydroxyethyl acrylate in a mass ratio of 5:3:1. Step 3: Add the blended elastomer to the grafted modified fluororubber and continue mixing. The mixing temperature is 70℃, the mixing time is 15min, and the mixing speed is 30rpm. After mixing, cool to room temperature and discharge to obtain an oil-resistant elastomer substrate. The mass ratio of the grafted modified fluororubber to the blended elastomer is 100:25, and the blended elastomer is perfluorosilicone rubber.

[0058] A method for preparing an oil-resistant, leak-proof asbestos gasket material includes the following preparation steps: S1. The oil-resistant elastomer base material, reinforcing filler, crosslinking agent, plasticizer, anti-aging agent and penetration inhibitor are put into the internal mixer and mixed. The temperature is controlled at 80℃, the speed is 35rpm, the mixing time is 18min, and after the mixture is uniform, vacuum degassing is performed. The vacuum degree is -0.07MPa and the degassing time is 3min. After vacuum degassing, the composite compound is obtained. S2. The composite compound rubber is molded and vulcanized. The molding and vulcanization temperature is 120℃, the vulcanization pressure is 10MPa, the vulcanization time is 8min, and after heat preservation and shaping, it is demolded to obtain the gasket blank. S3. The gasket blank is subjected to constant temperature secondary vulcanization treatment at a temperature of 150℃ for 2.5 hours. After curing, the edges and corners are trimmed to obtain an oil-resistant, sealing, and leak-proof asbestos gasket material.

[0059] Performance testing The comprehensive performance of the oil-resistant, leak-proof asbestos gasket materials prepared in Examples 1-3 and Comparative Examples 1-6 of this application was tested respectively, and the specific tests are as follows: Normal tensile strength test: The test was conducted in accordance with the national standard GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber"; Normal Shore hardness test: The test is conducted in accordance with the national standard GB / T 531.1-2008 "Test method for indentation hardness of vulcanized rubber or thermoplastic rubber - Part 1: Shore hardness tester method (Shore hardness)"; Accelerated aging test in hot air: Referring to the national standard GB / T 3512-2014 "Accelerated aging and heat resistance test of vulcanized rubber or thermoplastic rubber in hot air", the aging tensile strength and Shore hardness were tested after heat aging at 175℃ for 168h. Oil corrosion resistance test: The prepared oil-resistant and leak-proof asbestos gasket material was immersed in IRM 903 mineral oil (100℃×72h) to test the tensile strength and Shore hardness after immersion. Oil sealing performance: Tested in accordance with national standard GB / T 540-2008 "Test Method for Oil-resistant Asbestos Rubber Sheets"; The specific test results are shown in Table 1.

[0060] Table 1. Performance parameters of oil-resistant, leak-proof asbestos gasket materials in Examples 1-3 and Comparative Examples 1-6 As shown in Table 1, the oil-resistant, leak-proof asbestos gasket materials prepared in Examples 1-3 of this application, through the synergistic effect of fluororubber graft modification and dual elastomer blending, enable the gasket material to achieve both high strength and reliable oil-resistant sealing. Its normal tensile strength reaches 16.8-17.6 MPa, and it exhibits high strength retention rate after heat aging and oil immersion, small hardness fluctuation, and excellent dimensional stability. Furthermore, its aging resistance and oil resistance are significantly improved, effectively addressing the problem of easy penetration and sealing failure of traditional asbestos gasket materials after long-term use, and making it suitable for long-term sealing requirements under harsh working conditions.

[0061] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. An oil-resistant, leak-proof asbestos gasket material, characterized in that, The raw materials include the following parts by weight: 45-65 parts of oil-resistant elastomer base material, 20-35 parts of reinforcing filler, 2-5 parts of crosslinking agent, 1-3 parts of plasticizer, 1-2 parts of anti-aging agent and 3-5 parts of penetration inhibitor.

2. The oil-resistant, leak-proof asbestos gasket material according to claim 1, characterized in that, The method for preparing the oil-resistant elastomer substrate includes the following preparation steps: Step 1: Put the raw fluororubber into a two-roll mill for plasticizing to obtain plasticized fluororubber compound; Step 2: Transfer the plasticized fluororubber compound into an internal mixer, add the initiator and graft monomer, and carry out a constant temperature internal mixing reaction to obtain grafted modified fluororubber. Step 3: Add the first blended elastomer and the second blended elastomer to the grafted modified fluororubber in sequence, continue to mix, and after the mixing is completed, cool to room temperature and discharge to obtain the oil-resistant elastomer substrate.

3. The oil-resistant, leak-proof asbestos gasket material according to claim 2, characterized in that, In step 1, the fluororubber raw material is a polyvinylidene fluoride-hexafluoropropylene copolymer and / or a tetrafluoroethylene-hexafluoropropylene-vinylidene fluoride terpolymer.

4. The oil-resistant, leak-proof asbestos gasket material according to claim 2, characterized in that, In step 1, the plasticizing temperature is 60-80℃, the plasticizing time is 8-15min, the roller gap of the open mill is controlled at 1-3mm, and the roller speed ratio is 1:1.2-1.

5.

5. The oil-resistant, leak-proof asbestos gasket material according to claim 2, characterized in that, In step 2, the grafting monomer is composed of perfluorooctyl ethyl acrylate, methyl methacrylate and hydroxyethyl acrylate in a mass ratio of 5-8:3-5:1-3.

6. The oil-resistant, leak-proof asbestos gasket material according to claim 2, characterized in that, In step 3, the mass ratio of grafted modified fluororubber, the first blended elastomer, and the second blended elastomer is 100:15-25:10-18; the first blended elastomer is nitrile rubber with an acrylonitrile content of 33-38%; and the second blended elastomer is perfluorosilicone rubber with a hardness of 40-50HA.

7. The oil-resistant, leak-proof asbestos gasket material according to claim 1, characterized in that, The reinforcing filler is composed of asbestos fibers, nano-silica, and talc in a mass ratio of 5-8:3-5:2-3.

8. The oil-resistant, leak-proof asbestos gasket material according to claim 1, characterized in that, The penetration inhibitor is one of organomontmorillonite, paraffin powder, or polytetrafluoroethylene powder.

9. A method for preparing an oil-resistant, leak-proof asbestos gasket material according to any one of claims 1-8, characterized in that, The preparation steps include the following: S1. The oil-resistant elastomer base material, reinforcing filler, crosslinking agent, plasticizer, anti-aging agent and penetration inhibitor are put into a mixer, mixed evenly, and after vacuum degassing, a composite compound is obtained. S2. The composite rubber compound is molded and vulcanized, and after heat preservation and shaping, it is demolded to obtain the gasket blank. S3. The gasket blank is subjected to constant temperature secondary vulcanization treatment. After curing, the edges and corners are trimmed to obtain oil-resistant, sealing, and leak-proof asbestos gasket material.

10. The method for preparing the oil-resistant, leak-proof asbestos gasket material according to claim 9, characterized in that, In step S2, the molding and vulcanization temperature is 120-135℃, the vulcanization pressure is 10-12MPa, and the vulcanization time is 8-12min; in step S3, the constant temperature secondary vulcanization treatment vulcanization temperature is 150-165℃, and the vulcanization time is 2.5-3h.

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