A wear-resistant and high-temperature-resistant silicone rubber composition and a preparation method thereof

Abstract

The application relates to the technical field of silicone rubber, and particularly discloses a wear-resistant and high-temperature-resistant silicone rubber composition and a preparation method. The silicone rubber composition comprises the following raw materials in parts by mass: 55-70 parts of methyl vinyl silicone rubber, 15-20 parts of methyl phenyl vinyl silicone rubber, 5-10 parts of polytetrafluoroethylene micro powder, 10-18 parts of modified POE, 4-8 parts of reinforcing filler, 2-4 parts of processing aid, 18-25 parts of fumed white carbon black, 1-3 parts of divinyl tetramethyl disilazane, 1.5-3 parts of vulcanizing agent and 0.5-2 parts of crosslinking aid. The raw materials are mixed in a banbury mixer, melt-blended in a torque rheometer and formed into a plate in a plate vulcanizing machine to obtain the wear-resistant and high-temperature-resistant silicone rubber composition. The silicone rubber composition prepared through the synergistic effect of the raw materials has excellent wear resistance, high-temperature resistance, excellent mechanical properties and good stability.

Description

Technical Field

[0001] This invention relates to the field of silicone rubber technology, specifically to a wear-resistant and high-temperature resistant silicone rubber composition and its preparation method. Background Technology

[0002] Silicone rubber is a polymeric elastic material with silicon-oxygen bonds as the main chain and organic groups as side chains. It possesses excellent thermal stability and flexibility, and is widely used in electronics, automotive, aerospace, and medical devices. However, with the continuous development of industrial technology, higher requirements are being placed on the performance of silicone rubber materials, especially in harsh environments such as high temperature and high friction. Traditional silicone rubber is prone to molecular chain breakage and cross-linking network destruction under high temperature conditions, leading to increased hardness, decreased elasticity, accelerated friction loss, and significantly reduced wear resistance.

[0003] In existing technologies, inorganic fillers are typically added to improve the wear resistance of silicone rubber. However, the addition of a single filler has limited effect on improving wear resistance and can easily affect the mechanical and processing properties of silicone rubber due to uneven dispersion. Chinese patent application CN108641370A discloses a high-strength, high-temperature resistant silicone rubber composite material, comprising silicone rubber, EPDM rubber, polyurethane, fumed silica, carbon nanotubes, graphite, nano-calcium carbonate, mica iron oxide, montmorillonite, fly ash, calcium sulfate whiskers, zirconium fluoride, vulcanizing agent, methyl silicone oil, hexamethylcyclotrisilazane, vinyltriethoxysilane, and tetraethyl orthosilicate. This silicone rubber composite material exhibits good high-temperature resistance and wear resistance, but the addition of multiple compound fillers results in poor dispersibility and generally low mechanical strength. Chinese patent application CN119875376A discloses a high-temperature resistant silicone rubber, its preparation method, and its uses. Its raw materials include polyimide, silicone rubber, reinforcing agent fumed silica, activator zinc oxide, and heat-resistant agent cerium oxide, exhibiting excellent high-temperature aging resistance. The direct addition of inorganic raw materials and the introduction of polyimide can improve the performance of silicone rubber, but the high filler system leads to processing difficulties and loss of elasticity. Poor compatibility between raw materials can easily cause stress concentration, reduce the mechanical strength and wear resistance of silicone rubber, and affect the stability of the material.

[0004] Therefore, designing a silicone rubber composition with excellent wear resistance, high temperature resistance, and good overall performance is of great practical significance. Summary of the Invention

[0005] (a) Technical problems to be solved

[0006] To address the shortcomings of existing technologies, this invention provides a wear-resistant and high-temperature resistant silicone rubber composition and its preparation method, which solves the problems of general heat resistance and poor wear resistance of silicone rubber.

[0007] (II) Technical Solution

[0008] To achieve the above objectives, this invention discloses a wear-resistant and high-temperature resistant silicone rubber composition, comprising the following raw materials by weight: 55-70 parts of methyl vinyl silicone rubber, 15-20 parts of methyl phenyl vinyl silicone rubber, 5-10 parts of polytetrafluoroethylene micro powder, 10-18 parts of modified POE, 4-8 parts of reinforcing filler, 2-4 parts of processing aid, 18-25 parts of fumed silica, 1-3 parts of divinyltetramethyldisilazane, 1.5-3 parts of vulcanizing agent, and 0.5-2 parts of crosslinking aid;

[0009] The method for preparing the reinforcing filler includes the following steps:

[0010] S1. Mix anhydrous ethanol and deionized water in a volume ratio of 4:1 to obtain an ethanol solution. Add acetic acid to adjust the pH to 4. After mixing evenly, add γ-glycidoxypropyltrimethoxysilane and stir. Add nano-molybdenum disulfide, heat and react. After the reaction is complete, centrifuge, wash with anhydrous ethanol and deionized water, and dry to obtain epoxy-modified molybdenum disulfide.

[0011] S2. After mixing the ethanol solution and γ-aminopropyltriethoxysilane evenly, add nano boron nitride, heat up to allow the reaction to occur, filter after the reaction is complete, wash with anhydrous ethanol and deionized water, and dry to obtain amino-modified boron nitride.

[0012] S3. Mix epoxy-modified molybdenum disulfide, amino-modified boron nitride, N,N-dimethylformamide, and triethylamine evenly, heat, stir, and react in a nitrogen atmosphere. After the reaction is complete, wash with anhydrous ethanol and deionized water, and dry to obtain the reinforcing filler.

[0013] As a further aspect of the present invention: the addition ratio of ethanol solution, γ-glycidyl etheroxypropyltrimethoxysilane, and nano-molybdenum disulfide in S1 is 90-120mL: 8-10mL: 10g.

[0014] As a further aspect of the present invention: the reaction temperature in S1 is 60-70°C, and the reaction time is 6-8 hours.

[0015] As a further aspect of the present invention: the addition ratio of ethanol solution, γ-aminopropyltriethoxysilane, and nano-boron nitride in S2 is 120-150mL:9-12mL:10g.

[0016] As a further aspect of the present invention: the reaction temperature in S2 is 55-65℃, and the reaction time is 3-5h.

[0017] As a further aspect of the present invention: the addition ratio of epoxy-modified molybdenum disulfide, amino-modified boron nitride, N,N-dimethylformamide, and triethylamine in S3 is 55-75g:10g:180-200mL:0.1-0.2g.

[0018] As a further aspect of the present invention: the reaction temperature in S3 is 50-60℃, and the reaction time is 12-18h.

[0019] As a further aspect of the present invention, the method for preparing the modified POE includes the following steps:

[0020] A1. Mix ethanol solution with γ-methacryloxypropyltrimethoxysilane, adjust pH to 2-4 with dilute hydrochloric acid, stir and mix, add activated carbon fiber, heat and react. After the reaction is complete, wash with deionized water and dry to obtain alkenylated carbon fiber.

[0021] A2. Mix POE, perfluorooctyl acrylate, phenyl methacrylate, divinylbenzene, glycidyl methacrylate, alkenylated carbon fiber, and dicumyl peroxide evenly, add to a mixer, melt-blend, and after the reaction is complete, cool to obtain modified POE.

[0022] As a further aspect of the present invention: the ethanol solution in A1 is composed of anhydrous ethanol and deionized water in a volume ratio of 9:1.

[0023] As a further aspect of the present invention: the addition ratio of ethanol solution, γ-methacryloxypropyltrimethoxysilane, and activated carbon fiber in A1 is 150-180mL: 1.5-2.5g: 10g.

[0024] As a further aspect of the present invention: the reaction temperature in A1 is 68-75℃, and the reaction time is 2-3h.

[0025] As a further aspect of the present invention, the preparation method of the activated carbon fiber in A1 includes the following steps: desizing the carbon fiber, mixing 10g of carbon fiber with 120mL of acetone evenly, ultrasonically vibrating for 4h, washing with deionized water, drying to obtain pretreated carbon fiber, and then activating the pretreated carbon fiber with concentrated nitric acid, mixing 100mL of concentrated nitric acid with 5g of pretreated carbon fiber, heating, reacting at 105℃ for 4h, filtering, washing with deionized water, drying to obtain activated carbon fiber.

[0026] As a further aspect of the present invention: the addition ratio of POE, perfluorooctyl acrylate, phenyl methacrylate, divinylbenzene, glycidyl methacrylate, alkenylated carbon fiber, and dicumyl peroxide in A2 is 100g: 5-15g: 10-18g: 1-3g: 3-7g: 2-3g: 0.2-0.5g.

[0027] As a further aspect of the present invention: the melting and blending temperature in A2 is 175-185℃, the melting and blending time is 5-8 min, and the rotation speed is 45-55 r / min.

[0028] As a further aspect of the present invention: the vulcanizing agent is bis-tert-butylperoxyisopropylbenzene, the processing aid is hydroxyl silicone oil, and the crosslinking aid is TAIC.

[0029] A method for preparing the wear-resistant and high-temperature resistant silicone rubber composition according to any one of the above claims, comprising the following steps:

[0030] Step 1: In a mixer, add methyl vinyl silicone rubber, methyl phenyl vinyl silicone rubber, divinyltetramethyldisilazane, processing aids, fumed silica, reinforcing filler, polytetrafluoroethylene powder, crosslinking aids, and vulcanizing agent in sequence, mix, and discharge to obtain the compound.

[0031] Step 2: Add the compounded rubber and modified POE to the torque rheometer, melt-blend, discharge, and press into shape in a flat vulcanizing machine to obtain a wear-resistant and high-temperature resistant silicone rubber composition.

[0032] As a further aspect of the present invention: the mixing temperature in step one is 110-125℃, and the mixing time is 30-40min.

[0033] As a further aspect of the present invention: in step two, the melt blending temperature is 170-190℃, the blending time is 8-12 min, and the torque is 50-60 r / min.

[0034] As a further aspect of the present invention: in step two, the vulcanization process is carried out at a vulcanization temperature of 175-185℃, a vulcanization time of 10-18 min, and a pressure of 10-15 MPa.

[0035] (iii) Beneficial technical effects

[0036] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0037] (1) In this invention, the wear resistance and high temperature resistance of silicone rubber are effectively improved through the synergistic effect of various raw materials. The prepared silicone rubber composition has excellent mechanical properties and strong stability. Using methyl vinyl silicone rubber as the main base rubber can provide silicone rubber with basic flexibility, high elasticity and crosslinkable vinyl groups. The phenyl side chain in methyl phenyl vinyl silicone rubber hinders the cyclization degradation reaction of the siloxane main chain at high temperature, significantly improving thermal stability, while reducing the glass transition temperature of silicone rubber, so that it can maintain elasticity over a wider temperature range. By compounding the two rubbers, a matrix network of mutually synergistic flexible and rigid segments is formed, which ensures elasticity and processing fluidity. After vulcanization, a uniform crosslinked network can be formed, which effectively improves the high temperature resistance of the matrix.

[0038] (2) In this invention, the nano-molybdenum disulfide has a layered structure with low interlayer shear strength, exhibiting excellent friction reduction and wear resistance. The nano-boron nitride has a hexagonal crystal structure, possessing excellent thermal conductivity and high-temperature stability. Modification of the two inorganic nanoparticles effectively improves their dispersibility and prevents agglomeration. Furthermore, the two complementary inorganic nanomaterials are chemically bonded together to form a hybrid filler, which is added to the matrix as a reinforcing filler. Through synergistic effects, it can prevent heat accumulation in silicone rubber, reduce shear force during friction, and improve the wear resistance and high-temperature resistance of the matrix. During the mixing process, polytetrafluoroethylene (PTFE) micropowder can fill the interlayer gaps of molybdenum disulfide, achieving directional dispersion through its layered structure, solving the problem of PTFE micropowder agglomeration, further reducing friction and wear, and improving the wear resistance of the matrix. Fumed silica fills the gaps between rubber molecular chains, increasing rubber hardness and reducing plastic deformation during friction, thereby reducing wear.

[0039] (3) In this invention, POE has excellent mechanical properties and high and low temperature performance, and can form an "island structure" with the rubber matrix. When the rubber is subjected to external force, the POE particles undergo elastic deformation, absorb impact energy, and prevent crack propagation. By modifying POE, the functional monomers introduced during the modification process effectively improve its compatibility with silicone rubber. Carbon fiber, as a rigid reinforcing fiber, can effectively bear stress and improve the strength, modulus, and wear resistance of the composite material. The fluorinated long chain of perfluorooctyl acrylate migrates to the material surface, giving the matrix extremely low surface energy and improving friction resistance. The benzene ring structure in phenyl methacrylate produces a π-π conjugation effect with the phenyl group in methylphenyl silicone rubber, which greatly improves the interfacial compatibility between POE and silicone rubber and reduces phase separation. The epoxy groups on glycidyl methacrylate can react with the active groups on the surface of the reinforcing filler and the chain ends of silicone rubber, increasing the interaction force between raw materials. Detailed Implementation

[0040] The technical solutions of the present invention will be clearly and completely described below with reference to the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without creative effort are within the scope of protection of the present invention.

[0041] Example 1: A method for preparing a reinforcing filler, comprising the following steps:

[0042] S1. Mix anhydrous ethanol and deionized water in a volume ratio of 4:1 to obtain an ethanol solution. Add acetic acid to adjust the pH to 4 and mix well. Add 8 mL of γ-glycidyl etheroxypropyltrimethoxysilane to 90 mL of the ethanol solution and stir to mix. Add 10 g of nano molybdenum disulfide and heat to 60 °C for 8 h. After the reaction is complete, centrifuge, wash with anhydrous ethanol and deionized water, and dry to obtain epoxy-modified molybdenum disulfide.

[0043] S2. Mix 120 mL of ethanol solution and 9 mL of γ-aminopropyltriethoxysilane evenly. The ethanol solution consists of anhydrous ethanol and deionized water in a volume ratio of 1:1. Add 10 g of nano boron nitride, heat to 55 °C and react for 5 h. After the reaction is complete, filter, wash with anhydrous ethanol and deionized water, and dry to obtain amino-modified boron nitride.

[0044] S3. Mix 55g of epoxy-modified molybdenum disulfide, 10g of amino-modified boron nitride, 180mL of N,N-dimethylformamide, and 0.1g of triethylamine evenly, heat, stir, and react at 50℃ in a nitrogen atmosphere for 18h. After the reaction is complete, wash with anhydrous ethanol and deionized water, and dry to obtain the reinforcing filler.

[0045] Example 2: A method for preparing a reinforcing filler, comprising the following steps:

[0046] S1. Mix anhydrous ethanol and deionized water in a volume ratio of 4:1 to obtain an ethanol solution. Add acetic acid to adjust the pH to 4 and mix well. Add 9 mL of γ-glycidyl etheroxypropyltrimethoxysilane to 110 mL of the ethanol solution and stir to mix. Add 10 g of nano molybdenum disulfide and heat to 65 °C for 7 h. After the reaction is completed, centrifuge, wash with anhydrous ethanol and deionized water, and dry to obtain epoxy-modified molybdenum disulfide.

[0047] S2. Mix 140 mL of ethanol solution and 11 mL of γ-aminopropyltriethoxysilane evenly. The ethanol solution consists of anhydrous ethanol and deionized water in a volume ratio of 1:1. Add 10 g of nano boron nitride, heat to 60 °C and react for 4 h. After the reaction is complete, filter, wash with anhydrous ethanol and deionized water, and dry to obtain amino-modified boron nitride.

[0048] S3. Mix 65g of epoxy-modified molybdenum disulfide, 10g of amino-modified boron nitride, 190mL of N,N-dimethylformamide, and 0.15g of triethylamine evenly, heat and stir, and react at 55℃ in a nitrogen atmosphere for 15h. After the reaction is complete, wash with anhydrous ethanol and deionized water, and dry to obtain the reinforcing filler.

[0049] Example 3: A method for preparing a reinforcing filler, comprising the following steps:

[0050] S1. Mix anhydrous ethanol and deionized water in a volume ratio of 4:1 to obtain an ethanol solution. Add acetic acid to adjust the pH to 4 and mix well. Add 10 mL of γ-glycidyl etheroxypropyltrimethoxysilane to 120 mL of the ethanol solution and stir to mix. Add 10 g of nano molybdenum disulfide and heat to 70 °C for 6 h. After the reaction is completed, centrifuge, wash with anhydrous ethanol and deionized water, and dry to obtain epoxy-modified molybdenum disulfide.

[0051] S2. Mix 150 mL of ethanol solution and 12 mL of γ-aminopropyltriethoxysilane evenly. The ethanol solution consists of anhydrous ethanol and deionized water in a volume ratio of 1:1. Add 10 g of nano boron nitride, heat to 65 °C and react for 3 h. After the reaction is complete, filter, wash with anhydrous ethanol and deionized water, and dry to obtain amino-modified boron nitride.

[0052] S3. Mix 75g of epoxy-modified molybdenum disulfide, 10g of amino-modified boron nitride, 200mL of N,N-dimethylformamide, and 0.2g of triethylamine evenly, heat, stir, and react at 60℃ in a nitrogen atmosphere for 12h. After the reaction is complete, wash with anhydrous ethanol and deionized water, and dry to obtain the reinforcing filler.

[0053] Example 4: A method for preparing modified POE, comprising the following steps:

[0054] A1. Mix 150 mL of ethanol solution with 1.5 g of γ-methacryloxypropyltrimethoxysilane. The ethanol solution consists of anhydrous ethanol and deionized water in a volume ratio of 9:1. Adjust the pH to 2 with dilute hydrochloric acid, stir and mix, add 10 g of activated carbon fiber, heat to 68 °C and react for 3 h. After the reaction is complete, wash with deionized water and dry to obtain alkenylated carbon fiber.

[0055] A2. Mix 100g of POE, 5g of perfluorooctyl acrylate, 10g of phenyl methacrylate, 1g of divinylbenzene, 3g of glycidyl methacrylate, 2g of alkenylated carbon fiber, and 0.2g of dicumyl peroxide evenly, add to a mixer, and melt-blend. The melting temperature is 175℃, the melting time is 8min, and the rotation speed is 45r / min. After the reaction is completed, cool to obtain modified POE.

[0056] Example 5: A method for preparing modified POE, comprising the following steps:

[0057] A1. Mix 160 mL of ethanol solution with 2 g of γ-methacryloxypropyltrimethoxysilane, wherein the ethanol solution consists of anhydrous ethanol and deionized water in a volume ratio of 9:1. Adjust the pH to 3 with dilute hydrochloric acid, stir and mix, add 10 g of activated carbon fiber, heat to 70 °C and react for 2.5 h. After the reaction is completed, wash with deionized water and dry to obtain alkenylated carbon fiber.

[0058] A2. Mix 100g of POE, 10g of perfluorooctyl acrylate, 12g of phenyl methacrylate, 2g of divinylbenzene, 5g of glycidyl methacrylate, 2.5g of alkenylated carbon fiber, and 0.4g of dicumyl peroxide evenly, add the mixture to a mixer, and melt-blend at a temperature of 180℃ for 7 minutes at a speed of 50 r / min. After the reaction is complete, cool to obtain modified POE.

[0059] Example 6: A method for preparing modified POE, comprising the following steps:

[0060] A1. Mix 180 mL of ethanol solution with 2.5 g of γ-methacryloxypropyltrimethoxysilane. The ethanol solution consists of anhydrous ethanol and deionized water in a volume ratio of 9:1. Adjust the pH to 4 with dilute hydrochloric acid, stir and mix, add 10 g of activated carbon fiber, heat to 75 °C and react for 2 h. After the reaction is complete, wash with deionized water and dry to obtain alkenylated carbon fiber.

[0061] A2. Mix 100g of POE, 15g of perfluorooctyl acrylate, 18g of phenyl methacrylate, 3g of divinylbenzene, 7g of glycidyl methacrylate, 3g of alkenylated carbon fiber, and 0.5g of dicumyl peroxide evenly, add to a mixer, and melt-blend. The melting temperature is 185℃, the melting time is 5min, and the rotation speed is 55r / min. After the reaction is completed, cool to obtain modified POE.

[0062] Example 7: A method for preparing a wear-resistant and high-temperature resistant silicone rubber composition, comprising the following steps:

[0063] Step 1: Weigh out 55 parts of methyl vinyl silicone rubber, 15 parts of methyl phenyl vinyl silicone rubber, 5 parts of polytetrafluoroethylene (PTFE) micro powder, 10 parts of modified POE, 4 parts of reinforcing filler, 2 parts of processing aid hydroxyl silicone oil, 18 parts of fumed silica, 1 part of divinyltetramethyldisilazane, 1.5 parts of vulcanizing agent bis(tert-butylperoxyisopropylbenzene), and 0.5 parts of crosslinking aid TAIC in sequence in a mixer. Mix the methyl vinyl silicone rubber, methyl phenyl vinyl silicone rubber, divinyltetramethyldisilazane, processing aid, fumed silica, reinforcing filler, PTFE micro powder, crosslinking aid, and vulcanizing agent in a mixer at a temperature of 110°C for 40 minutes. Discharge the mixture to obtain the compound.

[0064] Step 2: Add the compounded rubber and modified POE to a torque rheometer for melt blending at 170°C for 12 minutes at a torque of 50 r / min. Discharge the material and press it into shape in a flat vulcanizing machine. During vulcanization, the vulcanization temperature is 175°C, the vulcanization time is 18 minutes, and the pressure is 10 MPa to obtain a wear-resistant and high-temperature resistant silicone rubber composition.

[0065] The preparation method of the reinforcing filler used in this embodiment is the same as that of the reinforcing filler in Example 1, and the preparation method of the modified POE is the same as that of the modified POE in Example 4.

[0066] Example 8: A method for preparing a wear-resistant and high-temperature resistant silicone rubber composition, comprising the following steps:

[0067] Step 1: Weigh out 65 parts of methyl vinyl silicone rubber, 18 parts of methyl phenyl vinyl silicone rubber, 6 parts of polytetrafluoroethylene (PTFE) micro powder, 12 parts of modified POE, 5 parts of reinforcing filler, 2.5 parts of processing aid hydroxyl silicone oil, 20 parts of fumed silica, 1.5 parts of divinyltetramethyldisilazane, 1.8 parts of vulcanizing agent di-tert-butylperoxyisopropylbenzene, and 1 part of crosslinking aid TAIC in sequence in an internal mixer. Mix the methyl vinyl silicone rubber, methyl phenyl vinyl silicone rubber, divinyltetramethyldisilazane, processing aid, fumed silica, reinforcing filler, PTFE micro powder, crosslinking aid, and vulcanizing agent in a mixer at a temperature of 115°C for 35 minutes. Discharge the mixture to obtain the compound.

[0068] Step 2: Add the compounded rubber and modified POE to a torque rheometer for melt blending at 180°C for 9 minutes at a torque of 55 r / min. Discharge the material and press it into shape in a flat vulcanizing machine. During vulcanization, the vulcanization temperature is 180°C, the vulcanization time is 12 minutes, and the pressure is 12 MPa to obtain a wear-resistant and high-temperature resistant silicone rubber composition.

[0069] The preparation method of the reinforcing filler used in this embodiment is the same as that of the reinforcing filler in Example 2, and the preparation method of the modified POE is the same as that of the modified POE in Example 5.

[0070] Example 9: A method for preparing a wear-resistant and high-temperature resistant silicone rubber composition, comprising the following steps:

[0071] Step 1: Weigh out 65 parts of methyl vinyl silicone rubber, 18 parts of methyl phenyl vinyl silicone rubber, 8 parts of polytetrafluoroethylene (PTFE) micro powder, 15 parts of modified POE, 6 parts of reinforcing filler, 3 parts of processing aid hydroxyl silicone oil, 21 parts of fumed silica, 2 parts of divinyltetramethyldisilazane, 2 parts of vulcanizing agent di-tert-butylperoxyisopropylbenzene, and 1.5 parts of crosslinking aid TAIC in sequence in a mixer. Mix the methyl vinyl silicone rubber, methyl phenyl vinyl silicone rubber, divinyltetramethyldisilazane, processing aid, fumed silica, reinforcing filler, PTFE micro powder, crosslinking aid, and vulcanizing agent in a mixer at a temperature of 120°C for 35 minutes. Discharge the mixture to obtain the compound.

[0072] Step 2: Add the compounded rubber and modified POE to a torque rheometer for melt blending at 180°C for 10 minutes at a torque of 55 r / min. Discharge the mixture and press it into shape in a flat vulcanizing machine. During vulcanization, the vulcanization temperature is 180°C, the vulcanization time is 15 minutes, and the pressure is 12 MPa to obtain a wear-resistant and high-temperature resistant silicone rubber composition.

[0073] The preparation method of the reinforcing filler used in this embodiment is the same as that of the reinforcing filler in Example 2, and the preparation method of the modified POE is the same as that of the modified POE in Example 5.

[0074] Example 10: A method for preparing a wear-resistant and high-temperature resistant silicone rubber composition, comprising the following steps:

[0075] Step 1: Weigh out 70 parts of methyl vinyl silicone rubber, 20 parts of methyl phenyl vinyl silicone rubber, 10 parts of polytetrafluoroethylene (PTFE) micro powder, 18 parts of modified POE, 8 parts of reinforcing filler, 4 parts of processing aid hydroxyl silicone oil, 25 parts of fumed silica, 3 parts of divinyltetramethyldisilazane, 3 parts of vulcanizing agent di-tert-butylperoxyisopropylbenzene, and 2 parts of crosslinking aid TAIC in sequence in a mixer. Mix the methyl vinyl silicone rubber, methyl phenyl vinyl silicone rubber, divinyltetramethyldisilazane, processing aid, fumed silica, reinforcing filler, PTFE micro powder, crosslinking aid, and vulcanizing agent in a mixer at a temperature of 125°C for 30 minutes. Discharge the mixture to obtain the compound.

[0076] Step 2: Add the compounded rubber and modified POE to a torque rheometer for melt blending at 190°C for 8 minutes at a torque of 60 r / min. Discharge the material and press it into shape in a flat vulcanizing machine. During vulcanization, the vulcanization temperature is 185°C, the vulcanization time is 10 minutes, and the pressure is 15 MPa to obtain a wear-resistant and high-temperature resistant silicone rubber composition.

[0077] The preparation method of the reinforcing filler used in this embodiment is the same as that of the reinforcing filler in Example 3, and the preparation method of the modified POE is the same as that of the modified POE in Example 6.

[0078] Comparative Example 1: A method for preparing a wear-resistant and high-temperature resistant silicone rubber composition. Compared with Example 9, 6 parts of reinforcing filler were replaced with 5.2 parts of nano molybdenum disulfide and 0.8 parts of nano boron nitride. The remaining components and preparation method were completely consistent with Example 9.

[0079] Comparative Example 2: A method for preparing a wear-resistant and high-temperature resistant silicone rubber composition. Compared with Example 9, 15 parts of modified POE were replaced with 14.7 parts of POE and 0.3 parts of alkenylated carbon fiber. The remaining components and preparation methods were completely consistent with those of Example 9. The alkenylated carbon fiber was prepared in the same way as the alkenylated carbon fiber in Example 5.

[0080] Comparative Example 3: A method for preparing a wear-resistant and high-temperature resistant silicone rubber composition. Compared with Example 9, the reinforcing filler is replaced with fumed silica in equal amounts, and methyl phenyl vinyl silicone rubber is replaced with methyl vinyl silicone rubber in equal amounts. The fumed silica is 27 parts and the methyl vinyl silicone rubber is 83 parts. The remaining components and preparation method are completely consistent with Example 9.

[0081] The preparation method of activated carbon fiber described in the embodiments and comparative examples of this invention includes the following steps: desizing carbon fiber, mixing 10g of carbon fiber with 120mL of acetone evenly, ultrasonically vibrating for 4h, washing with deionized water, drying to obtain pretreated carbon fiber, and then activating the pretreated carbon fiber with concentrated nitric acid, mixing 100mL of concentrated nitric acid with 5g of pretreated carbon fiber, heating, reacting at 105℃ for 4h, filtering, washing with deionized water, drying to obtain activated carbon fiber.

[0082] The methyl vinyl silicone rubber used in the embodiments and comparative examples of this invention was purchased from Zhejiang Xin'an Chemical Co., Ltd., with a vinyl mass fraction of 0.16%; the methyl phenyl vinyl silicone rubber was purchased from Zhejiang Xin'an Chemical Co., Ltd., with a diphenylsiloxane repeat molar fraction of 10.1% and a vinyl mass fraction of 0.2%; POE was purchased from Mitsui Chemicals, Japan, as TAFMERDF610; carbon fiber was purchased from Toray Industries, Japan, as industrial grade, model T700; nano boron nitride was purchased from Beijing Deco Island Gold Technology Co., Ltd., with an average particle size of 50 nm; nano molybdenum disulfide was purchased from Beijing Deco Island Gold Technology Co., Ltd., with an average particle size of 50 nm; polytetrafluoroethylene resin was purchased from Daikin Industries, Ltd., as model M-18; other undisclosed reagents were all commercially available.

[0083] Performance testing

[0084] (1) Abrasion resistance test: According to the test standard GB / T 9867-2008 "Determination of abrasion resistance of vulcanized rubber or thermoplastic rubber (rotary roller abrasion tester method)", the test conditions were 5N load and 100r / min rotation speed. Abrasion resistance tests were conducted on the abrasion-resistant and high-temperature resistant silicone rubber compositions in Examples 7-10 and Comparative Examples 1-3. The test results are shown in Table 1.

[0085] Table 1

[0086]

[0087] As can be seen from the test results in Table 1, the compositions corresponding to Examples 7-10 have excellent wear resistance, with a wear amount ≤79mm. 3 The wear amount corresponding to Example 9 is 58mm. 3 In Comparative Example 1, replacing 6 parts of reinforcing filler with 5.2 parts of nano-molybdenum disulfide and 0.8 parts of nano-boron nitride resulted in poor dispersibility, easy agglomeration, easy wear and detachment, and high wear rate. In Comparative Example 2, the addition of unmodified POE and alkenylated carbon fiber increased wear rate. In Comparative Example 3, the absence of synthetic reinforcing filler and methylphenyl vinyl silicone rubber significantly reduced wear resistance, resulting in a wear rate of 146 mm. 3 .

[0088] (2) Mechanical property testing: According to the testing standard GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber", the tensile properties of the wear-resistant and high-temperature resistant silicone rubber compositions in Examples 7-10 and Comparative Examples 1-3 were tested using an Instron 5567 universal testing machine. The test results are shown in Table 2.

[0089] Table 2

[0090]

[0091] As can be seen from the test results in Table 2, the compositions corresponding to Examples 7-10 have excellent mechanical properties. The tensile strength of Example 9 reaches 14.9 MPa, and the elongation at break reaches 450%. In Comparative Example 1, the tensile strength and elongation at break decrease due to the aggregation of inorganic nanoparticles. In Comparative Example 2, the unmodified POE has poor compatibility with the matrix, forming a weak interface and becoming a stress concentration point, resulting in a significant decrease in elongation at break and strength. In Comparative Example 3, replacing the reinforcing filler with an equal amount of fumed silica and methylphenyl vinyl silicone rubber with an equal amount of methyl vinyl silicone rubber reduces the synergistic effect and significantly reduces the overall performance.

[0092] (3) High temperature resistance test: According to the test standard GB / T 3512-2014 "Accelerated aging and heat resistance test of vulcanized rubber or thermoplastic rubber in hot air", the tensile strength and elongation at break after aging were tested according to the test standard GB / T 528-2009 "Determination of tensile stress-strain properties of vulcanized rubber or thermoplastic rubber". The retention rate of tensile strength and elongation at break after aging was calculated. Tensile strength retention rate = tensile strength after aging / tensile strength before aging × 100%; elongation at break retention rate = elongation at break after aging / elongation at break before aging × 100%. The test results are shown in Table 3.

[0093] Table 3

[0094]

[0095] As can be seen from the test results in Table 3, the compositions corresponding to Examples 7-10 have excellent heat resistance, with small changes in tensile strength and elongation at break before and after aging. The introduced thermally conductive network structure effectively reduces heat accumulation, has high temperature resistance, excellent thermal stability, and excellent high-temperature aging resistance.

[0096] Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and variations can be made to these embodiments without departing from the principles and spirit of the present invention. All equivalent changes and improvements made within the scope of the present invention should still fall within the scope of the present invention.

Claims

1. A wear-resistant and high-temperature resistant silicone rubber composition, characterized in that: By weight, it includes the following raw materials: 55-70 parts of methyl vinyl silicone rubber, 15-20 parts of methyl phenyl vinyl silicone rubber, 5-10 parts of polytetrafluoroethylene micro powder, 10-18 parts of modified POE, 4-8 parts of reinforcing filler, 2-4 parts of processing aid, 18-25 parts of fumed silica, 1-3 parts of divinyltetramethyldisilazane, 1.5-3 parts of vulcanizing agent, and 0.5-2 parts of crosslinking aid; The method for preparing the reinforcing filler includes the following steps: S1. Mix anhydrous ethanol and deionized water in a volume ratio of 4:1 to obtain an ethanol solution. Add acetic acid to adjust the pH to 4. After mixing evenly, add γ-glycidoxypropyltrimethoxysilane and stir. Add nano-molybdenum disulfide, heat and react. After the reaction is complete, centrifuge, wash and dry to obtain epoxy-modified molybdenum disulfide. S2. After mixing the ethanol solution and γ-aminopropyltriethoxysilane evenly, add nano boron nitride, heat up, and react. After the reaction is complete, filter, wash, and dry to obtain amino-modified boron nitride. S3. Mix epoxy-modified molybdenum disulfide, amino-modified boron nitride, N,N-dimethylformamide, and triethylamine evenly, heat, stir, and react in a nitrogen atmosphere. After the reaction is complete, wash and dry to obtain the reinforcing filler. The preparation method of the modified POE includes the following steps: A1. Mix ethanol solution with γ-methacryloxypropyltrimethoxysilane, adjust pH to 2-4 with dilute hydrochloric acid, stir and mix, add activated carbon fibers, heat and react, wash and dry after the reaction is complete to obtain alkenylated carbon fibers. A2. Mix POE, perfluorooctyl acrylate, phenyl methacrylate, divinylbenzene, glycidyl methacrylate, alkenylated carbon fiber, and dicumyl peroxide evenly, add to a mixer, melt-blend, and after the reaction is complete, cool to obtain modified POE.

2. The wear-resistant and high-temperature resistant silicone rubber composition according to claim 1, characterized in that: The addition ratio of epoxy-modified molybdenum disulfide, amino-modified boron nitride, N,N-dimethylformamide, and triethylamine in S3 is 55-75g:10g:180-200mL:0.1-0.2g, the reaction temperature is 50-60℃, and the reaction time is 12-18h.

3. The wear-resistant and high-temperature resistant silicone rubber composition according to claim 1, characterized in that: The addition ratio of POE, perfluorooctyl acrylate, phenyl methacrylate, divinylbenzene, glycidyl methacrylate, alkenylated carbon fiber, and dicumyl peroxide in A2 is 100g: 5-15g: 10-18g: 1-3g: 3-7g: 2-3g: 0.2-0.5g.

4. The wear-resistant and high-temperature resistant silicone rubber composition according to claim 1, characterized in that: The melting and blending temperature in A2 is 175-185℃, the melting and blending time is 5-8 min, and the rotation speed is 45-55 r / min.

5. The wear-resistant and high-temperature resistant silicone rubber composition according to claim 1, characterized in that: The vulcanizing agent is bis-tert-butylperoxyisopropylbenzene, the processing aid is hydroxyl silicone oil, and the crosslinking aid is TAIC.

6. A method for preparing a wear-resistant and high-temperature resistant silicone rubber composition according to any one of claims 1-5, characterized in that: Includes the following steps: Step 1: In a mixer, add methyl vinyl silicone rubber, methyl phenyl vinyl silicone rubber, divinyltetramethyldisilazane, processing aids, fumed silica, reinforcing filler, polytetrafluoroethylene powder, crosslinking aids, and vulcanizing agent in sequence, mix, and discharge to obtain the compound. Step 2: Add the compounded rubber and modified POE to the torque rheometer, melt-blend, discharge, and press into shape in a flat vulcanizing machine to obtain a wear-resistant and high-temperature resistant silicone rubber composition.

7. The method for preparing a wear-resistant and high-temperature resistant silicone rubber composition according to claim 6, characterized in that: The mixing temperature in step one is 110-125℃, and the mixing time is 30-40 minutes.

8. The method for preparing a wear-resistant and high-temperature resistant silicone rubber composition according to claim 6, characterized in that: In step two, the melt blending temperature is 170-190℃, the blending time is 8-12 minutes, and the torque is 50-60 r / min.

9. The method for preparing a wear-resistant and high-temperature resistant silicone rubber composition according to claim 6, characterized in that: In step two, the vulcanization process involves a vulcanization temperature of 175-185℃, a vulcanization time of 10-18 minutes, and a pressure of 10-15 MPa.

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