Fiber-reinforced high-temperature-resistant sealing rubber strip and preparation process thereof

Abstract

The invention discloses a fiber-reinforced high-temperature-resistant sealing rubber strip, and relates to the technical field of vulcanized silicone rubber, the fiber-reinforced high-temperature-resistant sealing rubber strip is prepared from basic rubber, modified resin, a fiber filler, a powder filler and an auxiliary agent through banburying and open milling; and extruding and vulcanizing. The modified resin is prepared by the following process: mixing polymethylhydrosiloxane, tetramethylammonium hydroxide and absolute methanol, and heating and reacting in a dry nitrogen atmosphere to obtain polysiloxane; the preparation method comprises the following steps: dissolving epoxy functionalized maleimide, adding a platinum catalyst and polysiloxane, and heating and reacting in a dry nitrogen atmosphere to obtain the polysiloxane modified maleimide. Through preparation of the modified resin and modification of the fibers, the leap of the fibers and a matrix from physical anchoring to chemical bonding is realized in a silicone rubber vulcanization system, and the fiber-matrix interface strength is improved; stress can be efficiently transmitted to high-strength fibers from a relatively weak rubber matrix, so that the reinforcing effect of the fibers is fully exerted, and the mechanical strength of the rubber strip is greatly improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of vulcanized silicone rubber, in particular to a fiber-reinforced high-temperature-resistant sealing strip and a preparation process thereof. BACKGROUND

[0002] Silicone resin (SR) is an elastic polymer composed of a silicon-oxygen-silicon inorganic main chain and an organic side chain, which has good thermal stability, processability and other properties, and is widely used in aerospace, electronics, transportation, civil construction and other fields. General silicone rubber is generally used at a temperature range of -50-260℃ and remains elastic. When used as a sealing strip, the further requirement for the high-temperature resistance of silicone rubber material is increasing, and improving the high-temperature resistance of silicone rubber material is one of the current research focuses. High-performance rubber sealing materials are generally composite materials composed of high-performance rubber and high-performance fibers. Although fibers have good comprehensive performance, they still have poor high-temperature resistance and compression resistance. Therefore, we propose a fiber-reinforced high-temperature-resistant sealing strip and a preparation process thereof. SUMMARY

[0003] The present application aims to provide a fiber-reinforced high-temperature-resistant sealing strip and a preparation process thereof to solve the problems in the background art.

[0004] To solve the above technical problems, the present application provides the following technical solution: a fiber-reinforced high-temperature-resistant sealing strip, comprising the following components by mass: 100 parts of base rubber, 1-12 parts of modified resin, 8-23 parts of fiber filler, 28-50 parts of powder filler and 1.9-6.3 parts of auxiliary agent.

[0005] Further, the base rubber is silicone rubber, and the silicone rubber is selected from methyl vinyl silicone rubber.

[0006] In the above technical solution, the silicone rubber (methyl vinyl silicone rubber) has the characteristics of wide temperature resistance range, excellent weather resistance, ozone resistance, radiation resistance and good flexibility, and the formula does not contain easy-to-migrate plasticizers, which ensures the long-term stability of the performance and makes it have excellent durability and reliability; the vinyl group provides crosslinking active sites, balances the high and low temperature performance and processability, and improves the vulcanization efficiency and high and low temperature performance.

[0007] Further, the modified resin is silicone resin, and the silicone resin is selected from methyl phenyl silicone resin.

[0008] The silicone resin such as methyl phenyl silicone resin can greatly improve the thermal stability, ablation resistance and radiation resistance of the material by introducing phenyl groups, and can improve the hardness, modulus and rigidity of the sealing strip, but will reduce the elongation rate to some extent.

[0009] Further, the fiber filler includes but is not limited to one or more of organic fibers such as nylon fiber, aramid fiber, PI (polyimide) fiber, and inorganic fibers such as carbon fiber, basalt fiber.

[0010] Further, the fiber filler includes 5-15 parts of glass fiber and 3-8 parts of aramid fiber.

[0011] In the above technical solution, the fiber filler is aramid fiber and glass fiber. The addition of aramid fiber provides the rubber strip with extremely high specific strength and tear resistance, and its fibrillation structure can produce strong interaction with the rubber molecular chain. The glass fiber can provide high modulus and rigid support. The mixture of the two forms a three-dimensional network, greatly improving the tensile strength, modulus and compression permanent deformation of the rubber strip, ensuring that it does not fail under long-term high pressure sealing, and the rubber strip has excellent mechanical strength and creep resistance.

[0012] Further, the powder filler includes 20-35 parts of fumed white carbon black, 3-5 parts of iron oxide, and 5-10 parts of mica powder.

[0013] In the above technical solution, the powder filler is a composite of fumed white carbon black, iron oxide and mica powder. Fumed white carbon black can reinforce silicone rubber and provide the rubber strip with basic mechanical strength. Iron oxide as a high-efficiency heat-resistant agent can capture free radicals, significantly delaying the depolymerization and hardening of the silicone rubber main chain at high temperatures. Mica powder as a sheet-shaped heat insulation filler can effectively block the penetration of heat and oxygen. The two work together to increase the upper limit of the long-term use temperature of the rubber strip to 230-250℃ or even higher, thereby achieving extreme heat resistance.

[0014] The combination of fiber filler and powder filler can be adjusted by type and amount to design the thermal expansion coefficient (CTE) of the rubber strip to be compatible with the sealed material, preventing the generation of stress due to thermal cycling. Its good resilience and creep resistance ensure effective sealing force and overall functionality.

[0015] Further, the auxiliary agent includes 0.5-3.0 parts of a dispersing agent, 0.8-1.5 parts of a vulcanizing agent, and 0.6-1.8 parts of an antioxidant. The dispersing agent is one or a mixture of both of hydroxyl silicone oil and silazane; the vulcanizing agent is a peroxide vulcanizing agent, double-25 vulcanizing agent; and the antioxidant is antioxidant 168 and antioxidant 1076, with a mass ratio of (1.0-1.6):1.

[0016] In the above technical solution, antioxidant 168 (phosphite) and antioxidant 1076 (hindered phenol) are used as the antioxidant system to construct an efficient synergistic antioxidant system. Antioxidant 168 decomposes hydroperoxides, and antioxidant 1076 captures free radicals, which together significantly slows down the thermal oxidation process and extends the service life of the product in a high-temperature environment. The dispersant is selected as hydroxyl silicone oil and silazane, which can effectively treat the surface of white carbon black, prevent its agglomeration and structure, reduce the viscosity of raw rubber, improve the dispersibility of fibers and fillers, make the mixing process smoother, and make the final product performance more uniform, so that the prepared rubber strip has good processability and homogenization characteristics.

[0017] The double-25 vulcanizing agent is a special vinyl vulcanizing agent, which belongs to alkyl peroxide and has relatively low activity, and can only vulcanize silicone rubber containing vinyl groups.

[0018] A preparation process of a fiber-reinforced high-temperature-resistant sealing rubber strip, comprising the following processes: The base rubber, modified resin, fiber filler, powder filler and dispersant are mixed and mixed in a banbury mixer, and the material is cooled after discharging; The vulcanizing agent and antioxidant are added, and the thin pass is opened, and the material is discharged; The extruder is extruded to obtain a high-temperature-resistant sealing rubber strip.

[0019] Further, in the mixing process, the mixing chamber temperature is 50-70℃, the rotor speed is 30-60rpm, and the mixing time is 8-12min; the material is cooled to below 40℃ after discharging.

[0020] Further, in the thin pass process, the thin pass times are 3-5 times; The roll temperature of the open mill is ≤50℃, and the temperature is controlled below 60℃ when discharging.

[0021] Further, in the extrusion process, the temperature of each section of the extruder is set as follows: the feeding zone is 40-50℃, the plasticizing zone is 60-70℃, and the head / mouth die is 80-90℃.

[0022] Further, the high-temperature-resistant sealing rubber strip is vulcanized before use; The vulcanization process is as follows: primary vulcanization: temperature 160-180℃, time 5-15min; secondary vulcanization: temperature 200-250℃, time 2-6h; tertiary vulcanization: temperature 180-200℃, time 2-4h. The primary vulcanization is used for shaping and obtaining a basic crosslinking network; the secondary vulcanization ensures complete decomposition of peroxide and promotes full reaction between resin and filler / fiber, such as condensation and ring opening; the tertiary vulcanization eliminates byproducts and stabilizes the network structure.

[0023] Further, the fibers are subjected to a modification treatment, and the specific process is as follows: Tetrabutyl titanate was heated to 45–50 °C, acetylacetone and n-butanol were added, and the mixture was reacted for 100–150 min to form a mixture. Dimethyldiethoxysilane, phenyltrimethoxysilane, and aminosiloxane were added to the mixture. Water and acidic reagent were then slowly added while stirring, and the mixture was reacted at 55–65 °C for 40–60 min. Hexamethyldisiloxane was added, and the end-capping reaction was carried out for 30–60 min. Heating was stopped, the pH of the system was adjusted to 4–5, the system solution was mixed with water, and then diluted with water to obtain the wetting agent. The fiber filler is immersed in the sizing agent for 10-30 minutes, then removed and dried to obtain the modified fiber.

[0024] In the above technical solution, acetylacetone acts as a chelating agent, reacting first with tetrabutyl titanate to form a stable chelate. This effectively slows down the subsequent hydrolysis and condensation rate, preventing the formation of titanium dioxide precipitate. Tetrabutyl titanate provides an inorganic TiO2 network precursor, enhancing the coating's hardness, wear resistance, and adhesion to fibers. Acetylacetone, as a chelating agent, stabilizes tetrabutyl titanate, preventing its rapid hydrolysis and precipitation.

[0025] Then, dimethyldiethoxysilane, phenyltrimethoxysilane, and aminosiloxane are added sequentially to the above chelate solution (mixture). Dimethyldiethoxysilane introduces -CH3 groups, providing the coating with flexibility, hydrophobicity, and low surface energy; phenyltrimethoxysilane introduces -C6H5 groups, improving the coating's thermal stability, oxidation resistance, and resin compatibility; aminosiloxane (such as APTES) introduces -NH2 groups, providing chemical bonding ability (reactivity) with epoxy and other resins; an acidic catalyst (such as glacial acetic acid) is used to catalyze the hydrolysis and condensation reactions, ensuring the reaction proceeds under mild conditions; silane and titanane undergo co-hydrolysis and condensation reactions to form a transparent sol. Finally, hexamethyldisiloxane (MM) is added as a capping agent to cap the remaining -Si-OH groups, terminating the condensation reaction, stabilizing the sol, and adjusting the surface energy of the coating, thereby obtaining a stable hybrid sol wetting agent. The fiber filler is fully impregnated and then dried to allow the coating to further condense and cure, forming a surface coating and obtaining modified fiber.

[0026] Furthermore, the solid content of the sizing agent is 0.6–1.5 wt%. If the concentration is too low, the coating will be too thin and the effect will be poor; if the concentration is too high, the coating will be too thick, which will easily crack and make the fibers brittle.

[0027] Furthermore, in the mixture, the molar ratio of tetrabutyl titanate to acetylacetone is 1:(1.0 to 1.2). The ratio of tetrabutyl titanate to n-butanol is (6-10) g / 100mL.

[0028] Furthermore, the molar ratio of tetrabutyl titanate, dimethyldiethoxysilane, phenyltrimethoxysilane, aminosiloxane, and hexamethyldisiloxane is 1:(5-8):(2-4):(1-3):(1-2).

[0029] Furthermore, the aminosiloxane is selected from (3-aminopropyl)triethoxysilane (APTES) and N-(2-aminoethyl)-3-aminopropyltrimethoxysilane.

[0030] Furthermore, the acidic reagent is one of glacial acetic acid or 1M dilute hydrochloric acid.

[0031] In the above technical solution, the rigidity and high adhesion of TiO2 are combined with the flexibility of organosilicon through titanium-silicon hybridization, avoiding the brittleness problem of pure inorganic coatings. By adjusting the ratio of the three silanes (methyl, phenyl, and amino), the flexibility, thermal stability, hydrophobicity, and interfacial reactivity with specific resins of the coating can be precisely designed. The introduction of aminosilanes transforms the fiber bond from a purely physical bond to a potential chemical bond, significantly improving the interfacial bonding strength with the resin matrix, thereby more effectively transferring stress from the matrix to the fiber. The strategy of using acetylacetone to chelate the titanium source and hexamethyldisiloxane for end-capping greatly improves the stability of the sol, avoiding failure problems caused by rapid hydrolysis of the titanium source, making the process more repeatable and industrially viable.

[0032] Furthermore, the modified resin is an organosilicon epoxy resin, prepared by the following process: Polymethylhydrosiloxane was mixed with anhydrous methanol and heated to 60-65°C in a dry nitrogen atmosphere. Tetramethylammonium hydroxide was added and the mixture was kept at this temperature for 4-6 hours. After the reaction was completed, acidic cation exchange resin was added and the mixture was stirred for 2-4 hours to neutralize and remove the alkaline catalyst tetramethylammonium hydroxide. The ion exchange resin was removed by filtration and the mixture was rotary evaporated at 40-50°C to obtain polysiloxane with silane and methoxy side chains. Epoxy-functionalized maleimide was dissolved in anhydrous toluene, a platinum catalyst was added, and the mixture was heated to 60–80 °C under a dry nitrogen atmosphere. The polysiloxane obtained above was then added, and the reaction was carried out at 80–100 °C for 8–12 h. After the reaction was completed, the system was cooled to below 60 °C, and the solvent toluene was removed by rotary evaporation to obtain an organosilicon containing epoxy groups, maleimide rings, a siloxane backbone, and hydrolyzable methoxy groups, which is denoted as organosilicon epoxy resin.

[0033] Furthermore, the molar ratio of Si-H to anhydrous methanol in polymethylhydrosiloxane is 1:(0.3-0.6). Tetramethylammonium hydroxide is added as a 10 wt% methanol solution; the amount used is 0.5–1.0 wt% (relative to the mass of polymethylhydrosiloxane). The acidic cation exchange resin is NKC-9.

[0034] Furthermore, the molar ratio of Si-H in the polysiloxane to C=C in the epoxy-functionalized maleimide is 1:(0.8~1.1). The platinum catalyst is either a Karstedt catalyst or a chloroplatinic acid-isopropanol solution, and is used in an amount of 10–50 ppm (relative to the total mass).

[0035] In the above technical solution, under the action of the catalyst tetramethylammonium hydroxide, some Si-H bonds on polymethylhydrosiloxane (PMHS) undergo incomplete substitution with methanol, introducing some methoxy groups onto the PMHS chain to obtain a polysiloxane with silane and methoxy groups in the side chain, denoted as polysiloxane; at the same time, sufficient Si-H bonds are retained for subsequent hydrosilylation reactions. The resulting polysiloxane then undergoes a hydrosilylation reaction with epoxy-functionalized maleimide, grafting epoxy-functionalized maleimide onto the organosilicon molecular chain. The resulting organosilicon epoxy resin has epoxy groups, maleimide rings, a siloxane backbone, and hydrolyzable methoxy groups.

[0036] In the above technical solution, the various functional groups (epoxy, Si-H, methoxy, etc.) of the modified resin can form covalent bonds with the base rubber, powder filler, and modified fiber through chemical reactions, rather than physical adsorption. This completely solves the interfacial debonding problem caused by the mismatch of the thermal expansion coefficients of the materials, and significantly improves the interlayer bonding strength and durability at high temperatures. Under high-temperature vulcanization conditions, the epoxy and methoxy groups in the modified resin undergo ring-opening and condensation reactions with the active functional groups (such as hydroxyl and amino groups) on the surface of the powder filler and modified fiber, as well as the hydroxyl groups at the chain ends of the base rubber (silicone rubber), forming covalent bonds such as ether bonds and ester bonds; and the amino groups on the surface of the modified fiber can also interact with the free radicals generated by the vulcanization of rubber peroxide.

[0037] Localized rigid crosslinking points were constructed within a flexible silicone rubber matrix, forming an interpenetrating network of "rigid islands-flexible seas." This structure effectively disperses and transfers stress, significantly improving the tensile strength, modulus, and tear resistance of the rubber strip. The maleimide rings and siloxane backbone possess extremely high thermal stability; introducing them into the crosslinking network enhances the overall thermal stability and heat aging resistance of the rubber strip, preventing degradation and performance decline of the polymer backbone at high temperatures. Simultaneously, the modified resin molecular chains are relatively long, exhibiting a degree of flexibility, which can absorb and buffer internal stresses generated during vulcanization cooling and thermal cycling, preventing cracking and deformation of the fiber coating and rubber strip.

[0038] Furthermore, the epoxy-functionalized maleimide is prepared by the following process: Maleic anhydride and solvent are mixed, and epoxy amine is added at 0-5°C. The mixture is then heated to 10-25°C and reacted for 4-6 hours to generate an amic acid intermediate. Add a dehydrating agent, heat to 60-70℃, and react for 4-5 hours to form a maleimide ring. After the reaction is complete, pour the reaction solution into ice water to precipitate the solid, filter, wash the precipitate with water and cold ethanol, purify and recrystallize, and vacuum dry at 50-60℃ for 12-24 hours to obtain epoxy-functionalized maleimide.

[0039] Furthermore, the molar ratio of maleic anhydride to epoxide is (1.05–1.15):1; The epoxyamine is one or a mixture of p-aminophenyl glycidyl ether (CAS: 17558-76-8) and m-aminophenyl glycidyl ether (CAS: 457898-09-8); Epoxyamines are obtained by etherification, epoxidation, and deprotection of an aminophenol (such as p-hydroxyacetanilide) with epichlorohydrin. They are then stored in a low-temperature (short-term refrigeration / long-term freezing) environment, protected from light, dry, and sealed.

[0040] Furthermore, the solvent is selected from one or a mixture of DMF and NMP; The amount of solvent used should be such that the solid content of the system is between 20% and 30% to ensure good stirring and mass transfer; The dehydrating agent is a mixture of acetic anhydride and triethylamine, with a molar ratio of acetic anhydride to triethylamine of (2-3):1; the molar ratio of triethylamine to acetic anhydride is approximately 1:1.

[0041] In the above technical solution, the reactivity of the amino group with the acid anhydride is less temperature-dependent than that of the amino group with the epoxy group. Maleic anhydride is first dissolved in a solvent. Under ice-water bath cooling and vigorous stirring, epoxide is slowly added. At low temperatures, the reaction between the amino and epoxy groups is significantly inhibited, allowing the amino group to preferentially react with the more reactive acid anhydride. After the epoxide is added, the reaction system is brought back to room temperature and stirred to ensure complete formation of the amyl acid. If necessary, the temperature can be heated to 40-50°C to promote the reaction, but close monitoring is required. During the reaction, maleic anhydride is always in excess. When epoxide enters the reaction system, a large amount of excess maleic anhydride molecules react with the amino group, thus protecting the amino group and preventing it from attacking its own epoxy group. A non-protic polar solvent is chosen, which facilitates the dissolution of reactants and heat dissipation; it also effectively dissolves the polar amyl acid intermediate, preventing its precipitation and uneven reaction, and prepares the reaction for subsequent dehydration of the epoxy group.

[0042] Acetic anhydride (Ac2O) and triethylamine (Et3N) were used as dehydrating agents for low-temperature cyclization. This temperature was sufficient to drive the dehydration and cyclization of the amyl acid, but was far below the initiation temperature of the epoxy group side reaction.

[0043] Furthermore, the modified resin is first premixed with powder filler, as follows: The modified resin is heated to 60-70℃ to reduce its viscosity and facilitate dispersion; Add powdered filler to a high-speed mixer and mix. Stir at low speed and add modified resin preheated to 60-70℃. Stir at high speed for 10-15 minutes. Let stand at room temperature for 2-12 hours to mature. Pass through a 20-40 mesh sieve.

[0044] Furthermore, the speed of the low-speed stirring is 100-500 rpm; The high-speed stirring speed is 1000-1500 rpm.

[0045] In the above technical solution, the methoxy group in the modified resin can undergo hydrolysis and condensation under high temperature and in the presence of moisture to form a Si-O-Si network, which condenses with the hydroxyl groups on the filler surface. This allows the alkoxy group in the modified resin to undergo a preliminary hydrolysis and condensation reaction with the hydroxyl groups on the filler surface, improving the pretreatment effect and allowing the resin to fully wet the filler surface.

[0046] Compared with the prior art, the beneficial effects of the present invention are as follows: 1. This invention achieves a leap from physical anchoring to chemical bonding between fibers and matrix in the silicone rubber vulcanization system through the preparation of modified resin and modification of fibers, thereby improving the fiber-matrix interface strength. This allows stress energy to be efficiently transferred from the relatively weak rubber matrix to the high-strength fibers, thus fully leveraging the reinforcing effect of the fibers and significantly improving the mechanical strength of the rubber strip, giving it high tensile strength, high modulus, and high tear resistance.

[0047] 2. This invention utilizes modified resins and modified fibers to form chemical bonds, enabling it to withstand higher temperatures. Even under long-term high-temperature conditions, the chemical bonds remain stable, exhibiting good resistance to compression set and maintaining sealing force without diminishing under thermal cycling and pressure fluctuations. This ensures the long-term structural integrity and sealing reliability of the adhesive strip under high-temperature conditions, significantly increasing its long-term operating temperature and providing excellent resistance to heat aging.

[0048] 3. This invention reduces the surface energy of the fibers by modifying the surface coating of the fibers, making them easier to disperse evenly in the rubber matrix during mixing, avoiding stress concentration points caused by fiber agglomeration, eliminating peeling and debonding between components, and improving the fatigue life and consistency of the product.

[0049] 4. In this invention, the modified resin and modified fiber do not act independently, but rather produce a synergistic effect of "1+1≫2". The modified resin, acting as a "multifunctional bridge", uses its abundant reactive functional groups to firmly connect the base rubber, powder filler, and modified fiber into a covalent whole. The modified fiber, acting as a "high-strength skeleton", is firmly fixed within the entire network by this bridge, greatly improving the macroscopic properties of the material. Detailed Implementation

[0050] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0051] In the following specific embodiments, all "parts" refer to parts by weight, unless otherwise specified; Aramid fiber: average length 0.71 mm; basalt fiber: diameter 50 nm; Fumed silica N20; iron oxide: nano-sized, particle size 30nm; mica powder: 100μm; The base rubber is methyl vinyl silicone rubber (MVSR): 110-2B, with a molecular weight of 450,000-700,000 and a vinyl content of 0.15-0.18 mol%. The dispersant is hydroxyl silicone oil PMX-200; the vulcanizing agent is bis(2,5-dimethyl-2,5-diethane); the antioxidants are antioxidant 168 and antioxidant 1076, with a mass ratio of 1.2:1.

[0052] Polymethylhydrosiloxane: DY-H202M, hydrogen content ≥1.5%; The acidic cation exchange resin is NKC-9; the platinum catalyst is Karstedt catalyst. Methylphenyl silicone resin: GR302A, viscosity 120 mPa·s (25℃), vinyl content 4.1 wt%.

[0053] Example 1: A process for preparing a fiber-reinforced high-temperature resistant sealing strip, comprising the following steps: Step 1: Preparation of epoxy-functionalized maleimide: Maleic anhydride and 2.3 times the amount of DMF solvent were mixed, and epoxyamine (p-aminophenyl glycidyl ether) was added at 5°C. The mixture was heated to 10°C and reacted for 6 hours to generate an amide acid intermediate. Acetic anhydride and triethylamine were added as dehydrating agents, and the mixture was heated to 60°C and reacted for 4 hours to form a maleimide ring. After the reaction was completed, the reaction solution was poured into ice water to precipitate a solid. The solid was filtered, washed with water and cold ethanol, purified, recrystallized, and dried under vacuum at 50°C for 12 hours to obtain epoxy-functionalized maleimide. The molar ratio of maleic anhydride to epoxyamine was 1.05:1; the molar ratio of acetic anhydride to triethylamine was 2:1; and the molar ratio of triethylamine to acetic anhydride was 1:1. Step 2, Preparation of modified resin: Polymethylhydrosiloxane was mixed with anhydrous methanol and heated to 65°C under a dry nitrogen atmosphere. 1.0 wt% tetramethylammonium hydroxide (added as a 10 wt% methanol solution) was then added, and the reaction was maintained at this temperature for 6 hours. After the reaction was complete, an acidic cation exchange resin was added, and the mixture was stirred for 4 hours to neutralize and remove the alkaline catalyst, tetramethylammonium hydroxide. The ion exchange resin was removed by filtration, and the mixture was rotary evaporated at 50°C to obtain the polysiloxane. The molar ratio of Si-H to anhydrous methanol in the polymethylhydrosiloxane was 1:0.6. Epoxy-functionalized maleimide was dissolved in anhydrous toluene, and a platinum catalyst was added. Under a dry nitrogen atmosphere, the mixture was heated to 60°C, and a polysiloxane was added. The reaction was carried out at 80°C for 8 hours. After the reaction was completed, the system was cooled to below 60°C, and the solvent toluene was removed by rotary evaporation to obtain an organosilicon epoxy resin, denoted as the modified resin. The molar ratio of Si-H in the polysiloxane to C=C in the epoxy-functionalized maleimide was 1:0.8. The amount of platinum catalyst (Pt) used was 10 ppm. Step 3: Modification of fiber fillers: Tetrabutyl titanate was heated to 45°C, acetylacetone and n-butanol were added, and the mixture was reacted for 100 min to form a mixture; the molar ratio of tetrabutyl titanate to acetylacetone was 1:1.0; the ratio of tetrabutyl titanate to n-butanol was 10 g / 100 mL. Add dimethyldiethoxysilane, phenyltrimethoxysilane, and aminosiloxane ((3-aminopropyl)triethoxysilane) to the mixture; then stir and slowly add water and an acidic reagent (glacial acetic acid), and react at 55°C for 40 min; add hexamethyldisiloxane and seal the reaction for 30 min; stop heating, adjust the pH of the system to 5, mix the system solution with water, and then dilute with water to obtain an impregnating agent with a solid content of 0.6 wt%; the molar ratio of tetrabutyl titanate, dimethyldiethoxysilane, phenyltrimethoxysilane, aminosiloxane, and hexamethyldisiloxane is 1:8:2:1:2; The fiber filler was immersed in the sizing agent for 10 minutes, removed, and dried to obtain the modified fiber; the fiber filler consisted of 5 parts glass fiber and 8 parts aramid fiber; Step 4: Preparation of high-temperature resistant sealing strips: Add the powdered filler to a high-speed mixer and mix at a low speed of 100 rpm. Add the modified resin preheated to 60°C and mix at a high speed of 1000 rpm for 15 minutes. Let it stand at room temperature for 2 hours to mature. Pass it through a 20-40 mesh sieve. The powdered filler includes 35 parts of fumed silica, 3 parts of iron oxide, and 5 parts of mica powder. The base rubber, modified resin, modified fiber, powder filler and dispersant are mixed in an internal mixer at a temperature of 50°C, a rotor speed of 30 rpm and a mixing time of 12 min; the discharged material is cooled to below 40°C. Add vulcanizing agent and antioxidant, and perform thin pass through the open mill 3 times; the roller temperature of the open mill should be ≤50℃, and the discharge temperature should be controlled below 60℃. The material is extruded in an extruder with the following temperature settings for each section: feeding zone 40℃, plasticizing zone 60℃, and die head / orifice 80℃, to obtain a high-temperature resistant sealing strip. The high-temperature resistant sealing strip comprises the following components by weight: 100 parts base rubber, 1 part modified resin, 8 parts modified fiber, 28 parts powder filler, and 1.9 parts additives. The additives include 0.5 parts dispersant, 0.8 parts vulcanizing agent, and 0.6 parts antioxidant.

[0054] Example 2: A process for preparing a fiber-reinforced high-temperature resistant sealing strip, comprising the following steps: Step 1: Preparation of epoxy-functionalized maleimide: Maleic anhydride and 3.1 times the amount of solvent DMF were mixed, and epoxy amine (p-aminophenyl glycidyl ether) was added at 2°C. The mixture was heated to 18°C ​​and reacted for 5 hours to generate an amide acid intermediate. Acetic anhydride and triethylamine were added as dehydrating agents, and the mixture was heated to 65°C and reacted for 4.5 hours to form a maleimide ring. After the reaction was completed, the reaction solution was poured into ice water to precipitate a solid. The solid was filtered, washed with water and cold ethanol, purified, recrystallized, and dried under vacuum at 55°C for 18 hours to obtain epoxy-functionalized maleimide. The molar ratio of maleic anhydride to epoxy amine was 1.1:1; the molar ratio of acetic anhydride to triethylamine was 2.5:1; and the molar ratio of triethylamine to acetic anhydride was 1:1. Step 2, Preparation of modified resin: Polymethylhydrosiloxane was mixed with anhydrous methanol and heated to 62°C under a dry nitrogen atmosphere. 0.8 wt% tetramethylammonium hydroxide (added as a 10 wt% methanol solution) was then added, and the mixture was kept at this temperature for 5 hours. After the reaction was complete, an acidic cation exchange resin was added, and the mixture was stirred for 3 hours to neutralize and remove the alkaline catalyst, tetramethylammonium hydroxide. The ion exchange resin was removed by filtration, and the mixture was rotary evaporated at 45°C to obtain the polysiloxane. The molar ratio of Si-H to anhydrous methanol in the polymethylhydrosiloxane was 1:0.4. Epoxy-functionalized maleimide was dissolved in anhydrous toluene, a platinum catalyst was added, and the mixture was heated to 70°C under a dry nitrogen atmosphere. Polysiloxane was then added, and the reaction was carried out at 90°C for 10 hours. After the reaction was completed, the system was cooled to below 60°C, and the solvent toluene was removed by rotary evaporation to obtain an organosilicon epoxy resin, denoted as the modified resin. The molar ratio of Si-H in the polysiloxane to C=C in the epoxy-functionalized maleimide was 1:0.9; the amount of platinum catalyst (Pt) was 30 ppm. Step 3: Modification of fiber fillers: Tetrabutyl titanate was heated to 48°C, acetylacetone and n-butanol were added, and the mixture was reacted for 120 min to form a mixture; the molar ratio of tetrabutyl titanate to acetylacetone was 1:1.1; the ratio of tetrabutyl titanate to n-butanol was 8 g / 100 mL. Add dimethyldiethoxysilane, phenyltrimethoxysilane, and aminosiloxane (N-(2-aminoethyl)-3-aminopropyltrimethoxysilane) to the mixture; then stir and slowly add water and an acidic reagent (glacial acetic acid), and react at 60°C for 50 min; add hexamethyldisiloxane and cap the reaction for 45 min; stop heating, adjust the pH of the system to 4.5, mix the system solution with water, and then dilute with water to obtain an impregnating agent with a solid content of 1.0 wt%; the molar ratio of tetrabutyl titanate, dimethyldiethoxysilane, phenyltrimethoxysilane, aminosiloxane, and hexamethyldisiloxane is 1:7:3:2:1.5; The fiber filler was immersed in the sizing agent for 20 minutes, removed, and dried to obtain the modified fiber; the fiber filler consisted of 10 parts glass fiber and 6 parts aramid fiber; Step 4: Preparation of high-temperature resistant sealing strips: Add the powdered filler to a high-speed mixer and mix at a low speed of 300 rpm. Add the modified resin preheated to 65°C and mix at a high speed of 1200 rpm for 12 minutes. Let it stand at room temperature for 6 hours to mature. Pass it through a 20-40 mesh sieve. The powdered filler includes 31 parts of fumed silica, 4 parts of iron oxide, and 8 parts of mica powder. The base rubber, modified resin, modified fiber, powder filler and dispersant are mixed in an internal mixer at a temperature of 60°C, a rotor speed of 50 rpm and a mixing time of 10 min; the discharged material is cooled to below 40°C. Add vulcanizing agent and antioxidant, and perform thin pass through the open mill 4 times; the roller temperature of the open mill should be ≤50℃, and the discharge temperature should be controlled below 60℃. The material is extruded in an extruder with the following temperature settings: feeding zone 45℃, plasticizing zone 65℃, and die head / orifice 85℃, to obtain a high-temperature resistant sealing strip. The high-temperature resistant sealing strip comprises the following components by weight: 100 parts base rubber, 6 parts modified resin, 15 parts modified fiber, 39 parts powder filler, and 4.2 parts additives. The additives include 1.8 parts dispersant, 1.2 parts vulcanizing agent, and 1.2 parts antioxidant.

[0055] Example 3: A process for preparing a fiber-reinforced high-temperature resistant sealing strip, comprising the following steps: Step 1: Preparation of epoxy-functionalized maleimide: Maleic anhydride, 4 times the amount of DMF and NMP were mixed, and epoxyamine (p-aminophenyl glycidyl ether) was added at 0°C. The mixture was heated to 25°C and reacted for 4 hours to generate an amide acid intermediate. Acetic anhydride and triethylamine were added as dehydrating agents, and the mixture was heated to 70°C and reacted for 5 hours to form a maleimide ring. After the reaction was completed, the reaction solution was poured into ice water to precipitate a solid. The solid was filtered, washed with water and cold ethanol, purified, recrystallized, and dried under vacuum at 60°C for 24 hours to obtain epoxy-functionalized maleimide. The molar ratio of maleic anhydride to epoxyamine was 1.15:1; the molar ratio of acetic anhydride to triethylamine was 3:1; and the molar ratio of triethylamine to acetic anhydride was 1:1. Step 2, Preparation of modified resin: Polymethylhydrosiloxane was mixed with anhydrous methanol and heated to 60°C under a dry nitrogen atmosphere. 0.5 wt% tetramethylammonium hydroxide (added as a 10 wt% methanol solution) was then added, and the mixture was kept at this temperature for 4 hours. After the reaction was complete, an acidic cation exchange resin was added, and the mixture was stirred for 2 hours to neutralize and remove the alkaline catalyst, tetramethylammonium hydroxide. The ion exchange resin was removed by filtration, and the mixture was rotary evaporated at 40°C to obtain the polysiloxane. The molar ratio of Si-H to anhydrous methanol in the polymethylhydrosiloxane was 1:0.3. Epoxy-functionalized maleimide was dissolved in anhydrous toluene, and a platinum catalyst was added. The mixture was heated to 80°C under a dry nitrogen atmosphere, and a polysiloxane was added. The reaction was carried out at 100°C for 12 hours. After the reaction was complete, the system was cooled to below 60°C, and the solvent toluene was removed by rotary evaporation to obtain an organosilicon epoxy resin, denoted as the modified resin. The molar ratio of Si-H in the polysiloxane to C=C in the epoxy-functionalized maleimide was 1:1.1; the amount of platinum catalyst (Pt) was 50 ppm. Step 3: Modification of fiber fillers: Tetrabutyl titanate was heated to 50°C, acetylacetone and n-butanol were added, and the mixture was reacted for 150 min to form a mixture; the molar ratio of tetrabutyl titanate to acetylacetone was 1:1.2; the ratio of tetrabutyl titanate to n-butanol was 6 g / 100 mL. Add dimethyldiethoxysilane, phenyltrimethoxysilane, and aminosiloxane (N-(2-aminoethyl)-3-aminopropyltrimethoxysilane) to the mixture; then stir and slowly add water and an acidic reagent (glacial acetic acid), and react at 65°C for 60 min; add hexamethyldisiloxane and seal the reaction for 60 min; stop heating, adjust the pH of the system to 4, mix the system solution with water, and then dilute with water to obtain an impregnating agent with a solid content of 1.5 wt%; the molar ratio of tetrabutyl titanate, dimethyldiethoxysilane, phenyltrimethoxysilane, aminosiloxane, and hexamethyldisiloxane is 1:5:4:3:1; The fiber filler was immersed in the sizing agent for 30 minutes, removed, and dried to obtain the modified fiber; the fiber filler included 15 parts glass fiber and 3 parts aramid fiber; Step 4: Preparation of high-temperature resistant sealing strips: Add the powdered filler to a high-speed mixer and mix at a low speed of 500 rpm. Add the modified resin preheated to 70°C and mix at a high speed of 1500 rpm for 10 minutes. Let it stand at room temperature for 12 hours to mature. Pass it through a 20-40 mesh sieve. The powdered filler includes 26 parts of fumed silica, 5 parts of iron oxide, and 10 parts of mica powder. The base rubber, modified resin, modified fiber, powder filler and dispersant are mixed in an internal mixer at a temperature of 70°C, a rotor speed of 60 rpm and a mixing time of 8 minutes; the discharged material is cooled to below 40°C. Add vulcanizing agent and antioxidant, and perform thin pass through the open mill 5 times; the roller temperature of the open mill should be ≤50℃, and the discharge temperature should be controlled below 60℃. The material is extruded in an extruder with the following temperature settings: feeding zone 50℃, plasticizing zone 70℃, and die head / orifice 90℃, to obtain a high-temperature resistant sealing strip. The high-temperature resistant sealing strip comprises the following components by weight: 100 parts base rubber, 12 parts modified resin, 23 parts modified fiber, 50 parts powder filler, and 6.3 parts additives. The additives include 3.0 parts dispersant, 1.5 parts vulcanizing agent, and 1.8 parts antioxidant.

[0056] Comparative Example 1: A process for preparing a fiber-reinforced high-temperature resistant sealing strip, comprising the following steps: Step 1: Preparation of modified resin: Polymethylhydrosiloxane was mixed with anhydrous methanol and heated to 65°C under a dry nitrogen atmosphere. 1.0 wt% tetramethylammonium hydroxide (added as a 10 wt% methanol solution) was then added, and the reaction was maintained at this temperature for 6 hours. After the reaction was complete, an acidic cation exchange resin was added, and the mixture was stirred for 4 hours to neutralize and remove the alkaline catalyst, tetramethylammonium hydroxide. The ion exchange resin was removed by filtration, and the mixture was rotary evaporated at 50°C to obtain the polysiloxane. The molar ratio of Si-H to anhydrous methanol in the polymethylhydrosiloxane was 1:0.6. Glycidyl acrylate was dissolved in anhydrous toluene, a platinum catalyst was added, and the mixture was heated to 60°C under a dry nitrogen atmosphere. Polysiloxane was then added, and the reaction was carried out at 80°C for 8 hours. After the reaction was completed, the system was cooled to below 60°C, and the solvent toluene was removed by rotary evaporation to obtain an organosilicon epoxy resin, denoted as the modified resin. The molar ratio of Si-H in the polysiloxane to C=C in the glycidyl acrylate was 1:0.8. The amount of platinum catalyst (Pt) used was 10 ppm. Steps 2-3 are the same as steps 3-4 in Example 1, resulting in a high-temperature resistant sealing strip.

[0057] Comparative Example 2: A process for preparing a fiber-reinforced high-temperature resistant sealing strip, using methylphenyl silicone resin as the modified resin, and steps 1-2 being the same as steps 3-4 in Example 1, to obtain a high-temperature resistant sealing strip.

[0058] Comparative Example 3: A preparation process for a fiber-reinforced high-temperature resistant sealing strip, comprising the following processes: Step 1: Modification of fiber fillers: Dimethyldiethoxysilane, phenyltrimethoxysilane, and aminosiloxane (selected as (3-aminopropyl)triethoxysilane) were mixed; then water and an acidic reagent (glacial acetic acid) were slowly added while stirring, and the mixture was reacted at 55°C for 40 min; hexamethyldisiloxane was added, and the reaction was capped for 30 min; heating was stopped, the pH of the system was adjusted to 5, the system solution was mixed with water, and then diluted with water to obtain an impregnating agent with a solid content of 0.6 wt%; the molar ratio of dimethyldiethoxysilane, phenyltrimethoxysilane, aminosiloxane, and hexamethyldisiloxane was 8:2:1:2; The fiber filler was immersed in the sizing agent for 10 minutes, removed, and dried to obtain the modified fiber; the fiber filler consisted of 15 parts aramid fiber and 3 parts glass fiber; Step 2 is the same as step 2 in Comparative Example 2, and a high-temperature resistant sealing strip is obtained.

[0059] Comparative Example 4: A process for preparing a fiber-reinforced high-temperature resistant sealing strip, comprising the following steps: The base rubber, modified resin, fiber filler, powder filler and dispersant are mixed in an internal mixer at a temperature of 50°C, a rotor speed of 30 rpm and a mixing time of 12 min; the discharged material is cooled to below 40°C. Add vulcanizing agent and antioxidant, and perform thin pass through the open mill 3 times; the roller temperature of the open mill should be ≤50℃, and the discharge temperature should be controlled below 60℃. The material is extruded in an extruder with the following temperature settings: feeding zone 40℃, plasticizing zone 60℃, and die head / orifice 80℃, to obtain a high-temperature resistant sealing strip. The high-temperature resistant sealing strip comprises the following components by weight: 100 parts base rubber, 1 part modified resin methyl phenyl silicone resin, 8 parts fiber filler, 28 parts powder filler, and 1.9 parts additives. The additives include 0.5 parts dispersant, 0.8 parts vulcanizing agent, and 0.6 parts antioxidant. The fiber filler includes 15 parts aramid fiber and 8 parts glass fiber. The powder filler includes 35 parts fumed silica, 3 parts iron oxide, and 5 parts mica powder.

[0060] Experiment: High-temperature resistant sealing strips obtained in Examples 1-3 and Comparative Examples 1-4 were vulcanized. The vulcanization process was as follows: First vulcanization: temperature 170℃, duration 10 min; Second vulcanization: temperature 225℃, duration 4 h; Third vulcanization: temperature 190℃, duration 3 h. Samples were prepared, and their performance was tested and the test results were recorded. Using HB 5481 as a reference standard, the vacuum bag was sealed with a sealing strip and evacuated to a gauge pressure of 9.8 × 10⁻⁶ at room temperature. 4 Pa, close the valve, and wait for the vacuum gauge reading to drop to 6.8 × 10⁻⁶. 4 Timing begins at Pa, and the decrease in the vacuum gauge reading within 5 minutes is recorded to characterize the room temperature sealing performance of the sample. Using HB 5481 as a reference standard, the vacuum bag was sealed with a sealing strip, heated to 180±2℃, and kept at that temperature for 3 hours. The sealing performance was tested at room temperature with an experimental temperature of 180±2℃, and the temperature drop was measured to characterize the high-temperature sealing performance of the sample. Using GB / T528-2009 as a reference standard, dumbbell-shaped specimens were stretched at a constant speed of 500 mm / min on a universal testing machine until the specimens broke; the maximum stress (tensile strength) and the stress at a specific elongation (100% constant elongation stress to characterize tensile modulus) were recorded during the process.

[0061] Using GB / T529-2008 as a reference standard, notched specimens are stretched on a tensile testing machine to test their tear strength in order to characterize their tear resistance.

[0062] Using GB / T7759.1-2015 as a reference standard, a cylindrical specimen is placed in a fixture and compressed to the specified deformation amount (25%) at 200℃. After holding for 24 hours, it is taken out and allowed to recover at room temperature for 30 minutes. The thickness change is measured, and the permanent deformation rate is calculated to characterize the resistance to compressive permanent deformation.

[0063] Using GB / T3512-2014 as a reference standard, the sample was aged in a 250℃ high-temperature oven for 72 hours, then removed, cooled to room temperature, and its tensile strength was tested again. The rate of change was calculated to characterize its heat aging resistance.

[0064]

[0065] Based on the data in the table above, the following conclusions can be clearly drawn: The high-temperature resistant sealing strips obtained in Examples 1-3 are compared with those obtained in Comparative Examples 1-4. The test results show that... Compared with the comparative examples, the high-temperature resistant sealing strips obtained in Examples 1-3 have higher tensile strength, tensile modulus, and tear strength, and lower compression set, smaller change in tensile strength after heat aging, and lower pressure changes at both room temperature and high temperature. This fully demonstrates that the present invention improves the sealing performance, mechanical properties, compression resistance, and high-temperature resistance of the sealing strip.

[0066] Compared to Example 1, the modified resin in Comparative Example 1, made from polymethylhydrosiloxane, anhydrous methanol, and glycidyl acrylate, introduced epoxy groups but lacked the heat-resistant rigid structure of the maleimide ring, resulting in a significant decrease in its strength retention and compression set resistance at high temperatures. The modified resin in Comparative Example 2 was a methylphenyl silicone resin, which had acceptable compatibility with the rubber matrix, but lacked reactive groups (epoxy groups), failing to effectively couple fibers and fillers, leading to poor mechanical properties and easy destruction of physical crosslinking points at high temperatures, resulting in large compression set. In contrast, the modified resin in Example 1 introduced both a maleimide ring (extremely high heat resistance) and epoxy groups (good interfacial bonding with fibers and fillers), and exhibited excellent compatibility with the rubber matrix, resulting in superior performance.

[0067] In Comparative Example 3, the fiber filler was modified with dimethyldiethoxysilane, phenyltrimethoxysilane, aminosiloxane, and hexamethyldisiloxane. The sizing agent lacked tetrabutyl titanate, relying solely on organosilanes for surface treatment. This resulted in a coating with poor heat resistance and mechanical anchoring, leading to a decrease in fiber reinforcement. In contrast, the fiber treated with a composite siloxane sizing agent containing tetrabutyl titanate as a precursor formed a robust organic-inorganic hybrid coating on the fiber surface, significantly enhancing the interfacial bonding and heat resistance between the fiber and the rubber matrix. In Comparative Example 4, the fiber filler was unmodified, and the powder filler was not premixed with the modified resin. This resulted in poor fiber-matrix bonding, making it prone to stress defects; the filler also tended to agglomerate and disperse unevenly.

[0068] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from the spirit or essential characteristics of the invention. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, it is intended that all variations falling within the meaning and scope of equivalents of the claims be included within the present invention.

Claims

1. A process for preparing a fiber-reinforced high-temperature resistant sealing strip, characterized in that: Including the following processes: The base rubber, modified resin, fiber filler, powder filler, and dispersant are mixed in an intensive mixer; vulcanizing agent and antioxidant are added, and the mixture is then rolled in a thin pass; the mixture is then extruded to obtain a high-temperature resistant sealing strip. The modified resin is an organosilicon epoxy resin, which is prepared by the following process: Polymethylhydrosiloxane was mixed with anhydrous methanol and heated to 60-65°C in a dry nitrogen atmosphere. Tetramethylammonium hydroxide was added and the reaction was maintained at this temperature for 4-6 hours to obtain polysiloxane. Epoxy-functionalized maleimide was dissolved in anhydrous toluene, a platinum catalyst was added, and the mixture was heated to 60–80°C in a dry nitrogen atmosphere. The polysiloxane was then added, and the mixture was reacted at 80–100°C for 8–12 hours to obtain an organosilicon epoxy resin.

2. The preparation process of the fiber-reinforced high-temperature resistant sealing strip according to claim 1, characterized in that: The fiber undergoes an impregnation modification treatment, the specific process of which is as follows: Tetrabutyl titanate was heated to 45–50 °C, and acetylacetone and n-butanol were added, reacting for 100–150 min. A mixture of dimethyldiethoxysilane, phenyltrimethoxysilane, and aminosiloxane, along with water and an acidic reagent, were added, and the mixture was reacted at 55–65 °C for 40–60 min. Hexamethyldisiloxane was then added, and the mixture was reacted for 30–60 min. The acid was adjusted, and the mixture was diluted with water to obtain the wetting agent. The fiber filler is impregnated in the sizing agent for 10-30 minutes to obtain the modified fiber.

3. The preparation process of a fiber-reinforced high-temperature resistant sealing strip according to claim 1, characterized in that: The epoxy-functionalized maleimide is prepared by the following process: Maleic anhydride and solvent are mixed, and epoxy amine is added at 0-5°C. The mixture is then heated to 10-25°C and reacted for 4-6 hours to generate an amic acid intermediate. Add a dehydrating agent, heat to 60-70℃, and react for 4-5 hours to obtain epoxy-functionalized maleimide.

4. The preparation process of a fiber-reinforced high-temperature resistant sealing strip according to claim 1, characterized in that: The modified resin is first premixed with the powder filler, as follows: Add powdered filler to a high-speed mixer and mix. Add modified resin preheated to 60-70℃ while stirring at low speed. Stir at high speed for 10-15 minutes. Let stand at room temperature for 2-12 hours to mature. Pass through a 20-40 mesh sieve.

5. The preparation process of a fiber-reinforced high-temperature resistant sealing strip according to claim 1, characterized in that: The high-temperature resistant sealing strip comprises the following components by weight: 100 parts base rubber, 1-12 parts modified resin, 8-23 parts fiber filler, 28-50 parts powder filler, and 1.9-6.3 parts additives; The additives include 0.5 to 3.0 parts of dispersant, 0.8 to 1.5 parts of vulcanizing agent, and 0.6 to 1.8 parts of antioxidant.

6. The preparation process of a fiber-reinforced high-temperature resistant sealing strip according to claim 5, characterized in that: The base rubber is silicone rubber, specifically methyl vinyl silicone rubber.

7. The preparation process of a fiber-reinforced high-temperature resistant sealing strip according to claim 5, characterized in that: The fiber filler comprises 5 to 15 parts glass fiber and 3 to 8 parts aramid fiber.

8. The preparation process of a fiber-reinforced high-temperature resistant sealing strip according to claim 5, characterized in that: The powder filler comprises 20-35 parts fumed silica, 3-5 parts iron oxide, and 5-10 parts mica powder.

9. The preparation process of a fiber-reinforced high-temperature resistant sealing strip according to claim 2, characterized in that: The molar ratio of tetrabutyl titanate, dimethyldiethoxysilane, phenyltrimethoxysilane, aminosiloxane, and hexamethyldisiloxane is 1:(5-8):(2-4):(1-3):(1-2); the molar ratio of tetrabutyl titanate and acetylacetone is 1:(1.0-1.2).

10. A fiber-reinforced high-temperature resistant sealing strip prepared by the preparation process according to any one of claims 1-9.

Images