High-toughness rubber composition, preparation method and application of high-toughness rubber composition to semiconductor sealing ring
By combining carboxyl-terminated liquid fluororubber with γ-(2,3-epoxypropoxy)propyltrimethoxysilane modification, surface-modified aramid fibers, and epoxy-modified fumed silica, a multi-scale reinforcing and toughening network was constructed. This solved the problems of deteriorated processing fluidity and weak interfacial bonding in fluororubber sealing materials when improving mechanical strength and heat resistance, and achieved improvements in high toughness, tear resistance, and processing stability.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- BEIJING HYLAND TECH CO LTD
- Filing Date
- 2026-03-09
- Publication Date
- 2026-05-12
AI Technical Summary
Existing fluororubber sealing materials, while improving mechanical strength and heat resistance, are prone to deterioration of processing fluidity and loss of elasticity. Furthermore, traditional fillers and additives may introduce pollution risks, making it difficult to balance toughness and stability.
A multi-scale reinforced and toughened network was constructed by reacting carboxyl-terminated liquid fluororubber with γ-(2,3-epoxypropoxy)propyltrimethoxysilane, combined with surface-modified aramid fibers and epoxy-modified fumed silica, thereby improving the interfacial bonding strength and dispersion stability through chemical bonding.
This study improved the high toughness, tear resistance, and processing stability of fluororubber materials, enhanced the macroscopic toughness and heat aging resistance of the materials, and reduced production costs and quality control difficulties.
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Figure CN122011636A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of polymer composite material technology, specifically relating to a high-toughness rubber composition, its preparation method, and its application in semiconductor sealing rings. Background Technology
[0002] In the semiconductor manufacturing and packaging field, core equipment and piping systems need to maintain extremely high sealing integrity under harsh operating conditions. Fluororubber, with its high bond energy of the CF bonds in its molecular chain, exhibits excellent high-temperature resistance, chemical corrosion resistance, and low permeability, and is therefore widely used in the manufacture of sealing rings for critical components such as cavity seals, valve gaskets, and pipeline connectors. The stability of its performance directly affects the cleanliness, process repeatability, and equipment operational reliability of semiconductor production, making it one of the fundamental materials ensuring the smooth operation of advanced processes.
[0003] Currently, to meet the demands for longer-lasting and more reliable sealing materials from the continuous upgrading of semiconductor processes, industry research on the modification of fluororubber mainly focuses on several directions: First, optimizing low-temperature resistance or media resistance by adjusting the monomer composition of the polymer backbone (such as the copolymerization ratio of vinylidene fluoride, hexafluoropropylene, and tetrafluoroethylene); second, using different types of reinforcing filler systems, such as nano-carbon black, modified silica, or inorganic nanoparticles, to improve its mechanical strength and wear resistance; and third, optimizing the vulcanization system (such as using bisphenol AF / accelerator BPP or peroxide systems) to construct a more stable three-dimensional network structure and improve heat aging resistance. However, these conventional technical approaches often introduce new problems or sacrifice other key properties when improving a specific performance. For example, the excessive addition of reinforcing fillers to improve hardness and resistance to compression set often leads to increased Mooney viscosity and deteriorated flowability of the rubber compound, making it difficult to mold complex cross-section seals and potentially impairing elastic recovery. Conversely, a tightly cross-linked network design aimed at improving heat resistance can easily lead to increased material brittleness, decreased toughness, tear resistance, and fatigue durability, making it prone to cracking under frequent temperature and pressure cycles, ultimately causing sudden seal failure. Furthermore, traditional fillers and additives may introduce leached metal ions or low-molecular-weight substances, posing a risk of contamination to the semiconductor process environment, and the complex formulation and process adjustments also increase production costs and the difficulty of quality control.
[0004] Therefore, the industry urgently needs to develop a new type of fluororubber composition to overcome the bottleneck of performance imbalance in existing technologies, so that while inheriting the excellent heat and chemical resistance, it can significantly improve toughness, tear resistance and processing stability to meet the growing demand of semiconductor manufacturing for high-reliability sealing materials. Summary of the Invention
[0005] This invention addresses the shortcomings of existing technologies by providing a high-toughness rubber composition. It aims to solve the technical problems in existing technologies, such as the deterioration of processing fluidity and damage to elasticity caused by the excessive addition of fillers to improve the mechanical strength of fluororubber sealing materials, the difficulty in achieving both high toughness and heat aging stability when constructing a tightly cross-linked network to improve heat resistance, and the performance imbalance and reliability decline caused by weak interfacial bonding in multi-component composite materials.
[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: A method for preparing a high-toughness rubber composition includes the following steps: Step 1: The carboxyl-terminated liquid fluororubber is reacted with γ-(2,3-epoxypropoxy)propyltrimethoxysilane (silane coupling agent KH560) to obtain a modified liquid fluororubber solution. Step 2: Immerse the surface-modified aramid fibers in a modified liquid fluororubber solution and react to obtain modified aramid fibers; Step 3: Mix and stir the carboxyl-terminated liquid fluororubber, reinforcing filler, acid absorber, and processing aid, add modified aramid fiber, and continue mixing and stirring to obtain the composite rubber compound; Step 4: Add vulcanizing agent and crosslinking agent to the composite rubber compound, stir, and obtain the high-toughness fluororubber composition.
[0007] Preferably, step one specifically includes: Add carboxyl-terminated liquid fluororubber to acetone and stir to obtain mixture A; γ-(2,3-epoxypropoxy)propyltrimethoxysilane and triethylamine were added to acetone and stirred to obtain mixture B. Heat mixture B to a set temperature, and add mixture A dropwise under a nitrogen atmosphere. After the addition is complete, allow the reaction to proceed. After the reaction is complete, cool the mixture to obtain a modified liquid fluororubber solution.
[0008] Preferably, the mass ratio of the carboxyl-terminated liquid fluororubber in mixture A, the γ-(2,3-epoxypropoxy)propyltrimethoxysilane in mixture B, and the triethylamine in mixture B is 1:(0.4-0.6):(0.01-0.012); when preparing mixture A, the amount of acetone used is 0.8-1.2 times the mass of the carboxyl-terminated liquid fluororubber; when preparing mixture B, the amount of acetone used is 1-1.5 times the mass of the γ-(2,3-epoxypropoxy)propyltrimethoxysilane; the reaction conditions are: under a nitrogen atmosphere, at a set temperature, for 6-10 hours. The set temperature is 95-100℃.
[0009] Preferably, step two specifically includes: Surface-modified aramid fibers were added to a modified liquid fluororubber solution, a catalyst was added, and the mixture was stirred to react. After the reaction was completed, the mixture was leached, washed, and dried to obtain modified aramid fibers. The mass ratio of surface-modified aramid fiber, modified liquid fluororubber solution, and catalyst is 10:(400-600):(3-5). The reaction conditions are a stirring speed of 200-400 r / min and a reaction temperature of 50-60℃ for 1.5-2.5 h. The catalyst is prepared by mixing deionized water and ethanol at a volume ratio of 1:(3-5).
[0010] Preferably, the surface-modified aramid fiber is prepared by the following steps: First, the aramid fiber is cleaned and dried, and then plasma treated to obtain surface-modified aramid fiber. The plasma treatment conditions are as follows: in an air atmosphere, at a power of 50-100W, for a treatment time of 3-5 minutes.
[0011] Preferably, in step three, the mass ratio of carboxyl-terminated liquid fluororubber, modified aramid fiber, reinforcing filler, acid absorber, and processing aid is 100:(15-25):(4-8):(1.5-3):(2-4), and the mixing conditions are: mixing at a stirring speed of 200-400 r / min for 8-12 min, and continuing mixing at a stirring speed of 200-400 r / min for 25-35 min.
[0012] Preferably, the acid absorbent comprises magnesium oxide; The processing aids include zinc stearate; The reinforcing filler includes epoxy-modified fumed silica.
[0013] Preferably, the epoxy-modified fumed silica is prepared by the following steps: The dried fumed silica was added to ethanol and ultrasonically dispersed to obtain a silica suspension. γ-(2,3-epoxypropoxy)propyltrimethoxysilane was added to deionized water and stirred to hydrolyze, yielding a silane coupling agent solution. The silica suspension was mixed with a silane coupling agent solution and reacted. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain the epoxy-modified fumed silica. The mass ratio of fumed silica in the silica suspension to γ-(2,3-epoxypropoxy)propyltrimethoxysilane in the silane coupling agent solution is 1:(4-6). When preparing the silica suspension, the amount of ethanol used is 25-35 times the mass of fumed silica. When preparing the silane coupling agent solution, the amount of deionized water used is 2-4 times the mass of γ-(2,3-epoxypropoxy)propyltrimethoxysilane. The reaction conditions are stirring at 60-80℃ for 2-4 hours.
[0014] Preferably, the carboxyl-terminated liquid fluororubber in step three is the same as the carboxyl-terminated liquid fluororubber in step one.
[0015] Preferably, in step four, the amount of vulcanizing agent added is 1.5-2.5% of the mass of the composite rubber compound, the amount of crosslinking aid added is 1-2% of the mass of the composite rubber compound, and the stirring conditions are: stirring at a speed of 200-300 r / min for 15-25 min under vacuum conditions. The vulcanizing agent includes 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; The crosslinking aid includes triallyl isocyanurate.
[0016] The present invention also discloses a high-toughness rubber composition prepared by the preparation method of the high-toughness rubber composition as described above.
[0017] Application of a high-toughness rubber composition as described above in semiconductor sealing rings.
[0018] Compared with the prior art, the beneficial effects of the present invention are as follows: In this invention, the introduction of aramid fibers and fumed silica constructs a multi-scale reinforcing and toughening framework for the rubber matrix. As a macroscopic reinforcing material, aramid fibers, with their high strength and high modulus, can effectively bear and disperse stress, preventing crack propagation. The nanoscale fumed silica dispersed in the matrix not only provides excellent reinforcement but also induces a large number of crazes and shear bands in the matrix under stress, consuming a large amount of energy. The combination of aramid fibers and fumed silica forms a synergistic reinforcing and toughening network from macroscopic to microscopic. In this invention, the end-group modification of liquid fluororubber is achieved by reacting the epoxy groups on the γ-(2,3-epoxypropoxy)propyltrimethoxysilane molecule with the end-groups of the liquid fluororubber. Then, the introduced end-group silane reacts with the surface active groups (-OH, -COOH) of the plasma-treated aramid fiber to construct a strong and flexible bridge between the aramid fiber and the rubber matrix, which is mainly based on chemical bonds. This not only improves the wettability and dispersion stability of the aramid fiber in the hydrophobic fluororubber matrix, but also efficiently couples the reinforcing effect of the rigid fiber with the deformation capability of the flexible rubber through strong chemical bonding. This greatly promotes the effective transmission and dissipation of stress at the interface, inhibits interface debonding, and thus improves the macroscopic toughness of the composite material. In this invention, the reinforcing filler (nanoscale fumed silica) undergoes epoxy modification. The introduced epoxy groups transform it from a physical filler into a chemically bondable active component. During vulcanization, it can covalently crosslink with the active groups on the rubber matrix and the surface of the modified fibers, thus firmly anchoring it in the crosslinked network. This not only solves the problem of nanofillers easily agglomerating in the matrix due to their large specific surface area and high surface energy, but also achieves highly uniform and stable dispersion in the rubber, fully leveraging its nano-effect. Furthermore, the silica, incorporated through chemical bonding, acts as a rigid nanonode, effectively transmitting and dispersing stress and constraining the large-scale slippage of rubber molecular chains. While improving the material's modulus and strength, its own load-bearing capacity and the resulting matrix silvering, shear yielding, and other micro-deformation mechanisms can form a multi-level synergy with the macro-toughening mechanisms such as fiber pull-out and bridging, jointly dissipating impact energy. Ultimately, this results in a composite material that achieves outstanding reinforcement while simultaneously achieving a breakthrough improvement in fracture toughness and tear resistance. Attached Figure Description
[0019] Figure 1 Thermogravimetric analysis (TGA) diagrams of fumed silica and epoxy-modified fumed silica prepared in Example 1 of this invention are shown. Figure 2 The graph shows the results of the processing performance test of the rubber compositions obtained in Examples 1-3 and Comparative Examples 1-3 of this invention. Figure 3 The graph shows the mechanical property test results of the rubber compositions obtained in Examples 1-3 and Comparative Examples 1-3 of this invention. Figure 4 The graph shows the results of the heat aging resistance test of the rubber compositions prepared in Examples 1-3 and Comparative Examples 1-3 of this invention. In the figure, 1 is fumed silica; 2 is epoxy-modified fumed silica prepared in Example 1. Detailed Implementation
[0020] 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.
[0021] Example 1 This embodiment discloses a method for preparing a high-toughness rubber composition, comprising the following steps: Step 1: Add the carboxyl-terminated liquid fluororubber to acetone. The amount of acetone is 0.8 times the mass of the carboxyl-terminated liquid fluororubber. Stir and mix to obtain mixture A. Add γ-(2,3-epoxypropoxy)propyltrimethoxysilane and triethylamine to acetone, with the amount of acetone being 1 times the mass of γ-(2,3-epoxypropoxy)propyltrimethoxysilane. Stir and mix to obtain mixture B. The mass ratio of the carboxyl-terminated liquid fluororubber in mixture A, the γ-(2,3-epoxypropoxy)propyltrimethoxysilane in mixture B, and the triethylamine in mixture B is 1:0.4:0.01. Mixture B was heated to 95°C, and mixture A was added dropwise under a nitrogen atmosphere. The dropwise addition time was controlled at 2 hours. After the addition was completed, the temperature was maintained at 95°C for 10 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a modified liquid fluororubber solution. Step 2: Add the surface-modified aramid fiber to the modified liquid fluororubber solution, add the catalyst, and the mass ratio of surface-modified aramid fiber, modified liquid fluororubber solution and catalyst is 10:400:3. React at 50℃ for 2.5h with stirring speed of 200r / min. After the reaction is completed, dredge the fiber, wash it three times with acetone, and dry it in a vacuum drying oven at 60℃ until constant weight to obtain modified aramid fiber. The catalyst is prepared by mixing deionized water and ethanol in a volume ratio of 1:3. Surface-modified aramid fibers are prepared by the following steps: Aramid fibers were washed three times with acetone, dried, and then placed in a plasma treatment device and treated for 5 minutes in an air atmosphere at 50W power to obtain surface-modified aramid fibers. Step 3: Mix and stir the carboxyl-terminated liquid fluororubber, epoxy-modified fumed silica, magnesium oxide, and zinc stearate. Add the modified aramid fiber and continue mixing and stirring to obtain the composite rubber compound. The mass ratio of carboxyl-terminated liquid fluororubber, modified aramid fiber, epoxy-modified fumed silica, magnesium oxide, and zinc stearate is 100:15:4:1.5:2. The mixing conditions are: mixing at a stirring speed of 200 r / min for 12 min, and continuing mixing at a stirring speed of 200 r / min for 35 min. Epoxy-modified fumed silica is prepared by the following steps: The dried fumed silica was added to ethanol, with the amount of ethanol being 30 times the mass of the fumed silica. The mixture was ultrasonically dispersed at a frequency of 50 kHz for 30 min to obtain a silica suspension. Add γ-(2,3-epoxypropoxy)propyltrimethoxysilane to deionized water, the amount of deionized water being 3 times the mass of γ-(2,3-epoxypropoxy)propyltrimethoxysilane, and stir and hydrolyze at room temperature for 30 min to obtain a silane coupling agent solution. The mass ratio of fumed silica in the silica suspension to γ-(2,3-epoxypropoxy)propyltrimethoxysilane in the silane coupling agent solution is 1:5. The silica suspension was mixed with the silane coupling agent solution and stirred at 70°C for 3 hours. After the reaction was completed, the mixture was centrifuged, the solid product was washed three times with ethanol, and dried in a vacuum drying oven at 50°C to constant weight to obtain epoxy-modified fumed silica. Depend on Figure 1 It can be seen that the grafting rate of the silane coupling agent KH560 is approximately 12%; Step 4: Add 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and triallyl isocyanurate to the composite rubber compound. The amount of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane added is 1.5% of the mass of the composite rubber compound, and the amount of triallyl isocyanurate added is 1% of the mass of the composite rubber compound. Stir at 200 r / min for 25 min under vacuum conditions to obtain a high-toughness fluororubber composition.
[0022] Example 2 This embodiment discloses a method for preparing a high-toughness rubber composition, comprising the following steps: Step 1: Add the carboxyl-terminated liquid fluororubber to acetone. The amount of acetone is 1.2 times the mass of the carboxyl-terminated liquid fluororubber. Stir and mix to obtain mixture A. Add γ-(2,3-epoxypropoxy)propyltrimethoxysilane and triethylamine to acetone, with the amount of acetone being 1.5 times the mass of γ-(2,3-epoxypropoxy)propyltrimethoxysilane. Stir and mix to obtain mixture B. The mass ratio of carboxyl-terminated liquid fluororubber in mixture A, γ-(2,3-epoxypropoxy)propyltrimethoxysilane in mixture B, and triethylamine in mixture B is 1:0.6:0.012. Heat mixture B to 100℃, add mixture A dropwise under nitrogen atmosphere, control the dropwise addition time to 2h, maintain the temperature at 100℃ for 6h after the addition is complete, cool to room temperature after the reaction is complete to obtain modified liquid fluororubber solution. Step 2: Add the surface-modified aramid fiber to the modified liquid fluororubber solution, add the catalyst, and the mass ratio of surface-modified aramid fiber, modified liquid fluororubber solution and catalyst is 10:600:5. React at 60℃ for 1.5h with stirring speed of 400r / min. After the reaction is completed, dredge the fiber, wash it three times with acetone, and dry it in a vacuum drying oven at 60℃ until constant weight to obtain modified aramid fiber. The catalyst is prepared by mixing deionized water and ethanol in a volume ratio of 1:5. Surface-modified aramid fibers are prepared by the following steps: Aramid fibers were washed three times with acetone, dried, and then placed in a plasma treatment device and treated for 3 minutes in an air atmosphere at 100W power to obtain surface-modified aramid fibers. Step 3: Mix and stir the carboxyl-terminated liquid fluororubber, epoxy-modified fumed silica, magnesium oxide, and zinc stearate. Add the modified aramid fiber and continue mixing and stirring to obtain the composite rubber compound. The mass ratio of carboxyl-terminated liquid fluororubber, modified aramid fiber, epoxy-modified fumed silica, magnesium oxide, and zinc stearate is 100:25:8:3:4. The mixing conditions are: mixing at a stirring speed of 400 r / min for 8 min, and continuing mixing at a stirring speed of 400 r / min for 25 min. The preparation method of epoxy-modified fumed silica is the same as in Example 1; Step 4: Add 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and triallyl isocyanurate to the composite rubber compound. The amount of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane added is 2.5% of the mass of the composite rubber compound, and the amount of triallyl isocyanurate added is 2% of the mass of the composite rubber compound. Stir at 300 r / min for 15 min under vacuum conditions to obtain a high-toughness fluororubber composition.
[0023] Example 3 This embodiment discloses a method for preparing a high-toughness rubber composition, comprising the following steps: Step 1: Add the carboxyl-terminated liquid fluororubber to acetone. The amount of acetone should be 1 times the mass of the carboxyl-terminated liquid fluororubber. Stir and mix to obtain mixture A. Add γ-(2,3-epoxypropoxy)propyltrimethoxysilane and triethylamine to acetone, with the amount of acetone being 1.2 times the mass of γ-(2,3-epoxypropoxy)propyltrimethoxysilane. Stir and mix to obtain mixture B. The mass ratio of carboxyl-terminated liquid fluororubber in mixture A, γ-(2,3-epoxypropoxy)propyltrimethoxysilane in mixture B, and triethylamine in mixture B is 1:0.5:0.011. Mixture B was heated to 98°C, and mixture A was added dropwise under a nitrogen atmosphere. The dropwise addition time was controlled at 2 hours. After the addition was completed, the temperature was maintained at 98°C for 8 hours. After the reaction was completed, the mixture was cooled to room temperature to obtain a modified liquid fluororubber solution. Step 2: Add the surface-modified aramid fiber to the modified liquid fluororubber solution, add the catalyst, and the mass ratio of surface-modified aramid fiber, modified liquid fluororubber solution and catalyst is 10:6500:4. React at 55℃ for 2 hours with stirring speed of 300 r / min. After the reaction is completed, dredge the fiber, wash it three times with acetone, and dry it in a vacuum drying oven at 60℃ until constant weight to obtain modified aramid fiber. The catalyst is prepared by mixing deionized water and ethanol in a volume ratio of 1:4. Surface-modified aramid fibers are prepared by the following steps: Aramid fibers were washed three times with acetone, dried, and then placed in a plasma treatment device and treated for 4 minutes in an air atmosphere at 80W power to obtain surface-modified aramid fibers. Step 3: Mix and stir the carboxyl-terminated liquid fluororubber, epoxy-modified fumed silica, magnesium oxide, and zinc stearate. Add the modified aramid fiber and continue mixing and stirring to obtain the composite rubber compound. The mass ratio of carboxyl-terminated liquid fluororubber, modified aramid fiber, epoxy-modified fumed silica, magnesium oxide, and zinc stearate is 100:20:6:2.2:3. The mixing conditions are: mixing at a stirring speed of 300 r / min for 10 min, and continuing mixing at a stirring speed of 30 r / min for 30 min. The preparation method of epoxy-modified fumed silica is the same as in Example 1; Step 4: Add 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and triallyl isocyanurate to the composite rubber compound. The amount of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane added is 2% of the mass of the composite rubber compound, and the amount of triallyl isocyanurate added is 1.5% of the mass of the composite rubber compound. Stir at 250 r / min for 20 min under vacuum conditions to obtain a high-toughness fluororubber composition.
[0024] Comparative Example 1 This comparative example discloses a method for preparing a high-toughness rubber composition, comprising the following steps: Step 1: Add the carboxyl-terminated liquid fluororubber to acetone. The amount of acetone is 0.8 times the mass of the carboxyl-terminated liquid fluororubber. Stir and mix to obtain mixture A. Step 2: Add the surface-modified aramid fiber to the mixture A. The mass ratio of the surface-modified aramid fiber to the mixture A is 10:400. Stir at 200 r / min and 50℃ for 2.5 h. After the reaction is complete, dredge the fiber, wash it three times with acetone, and dry it in a vacuum drying oven at 60℃ until constant weight to obtain the modified aramid fiber. The surface-modified aramid fiber is prepared by the following steps: Aramid fibers were washed three times with acetone, dried, and then placed in a plasma treatment device and treated for 5 minutes in an air atmosphere at 50W power to obtain surface-modified aramid fibers. Step 3: Mix and stir the carboxyl-terminated liquid fluororubber, fumed silica, magnesium oxide, and zinc stearate, add the modified aramid fiber, and continue mixing and stirring to obtain the composite rubber compound; The mass ratio of carboxyl-terminated liquid fluororubber, modified aramid fiber, fumed silica, magnesium oxide, and zinc stearate is 100.4:15:3.6:1.5:2. The mixing conditions are: mixing at a stirring speed of 200 r / min for 12 min, and continuing mixing at a stirring speed of 200 r / min for 35 min. Step 4: Add 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and triallyl isocyanurate to the composite rubber compound. The amount of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane added is 1.5% of the mass of the composite rubber compound, and the amount of triallyl isocyanurate added is 1% of the mass of the composite rubber compound. Stir at 200 r / min for 25 min under vacuum conditions to obtain a high-toughness fluororubber composition.
[0025] Comparative Example 2 This comparative example discloses a method for preparing a high-toughness rubber composition, comprising the following steps: Step 1: Mix and stir carboxyl-terminated liquid fluororubber, epoxy-modified fumed silica, magnesium oxide, and zinc stearate. Add aramid fiber and continue mixing and stirring to obtain a composite rubber compound. The mass ratio of carboxyl-terminated liquid fluororubber, aramid fiber, epoxy-modified fumed silica, magnesium oxide, and zinc stearate is 100:15:4:1.5:2. The mixing conditions are: mixing at a stirring speed of 200 r / min for 12 min, and continuing mixing at a stirring speed of 200 r / min for 35 min. The aramid fiber was not modified in any way, that is, it was not subjected to plasma treatment or fluororubber modification. The preparation method of epoxy-modified fumed silica is the same as in Example 1; Step 2: Add 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane and triallyl isocyanurate to the composite rubber compound. The amount of 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane added is 1.5% of the mass of the composite rubber compound, and the amount of triallyl isocyanurate added is 1% of the mass of the composite rubber compound. Stir at 200 r / min for 25 min under vacuum conditions to obtain a high-toughness fluororubber composition.
[0026] Comparative Example 3 The only difference between Comparative Example 3 and Example 1 is that the reinforcing filler is unmodified fumed silica.
[0027] In the above embodiments and comparative examples, the carboxyl-terminated liquid fluororubber is a pale yellow, transparent, viscous liquid with a viscosity of 10-20 Pa·s; the aramid fiber is a short-cut aramid fiber with an average length of 1 mm; the magnesium oxide is nano-magnesium oxide with an average particle size of 100 nm; and the fumed silica is nano-sized particles with an average particle size of 50 nm.
[0028] Test case The properties of the rubber compositions prepared in Examples 1-3 and Comparative Examples 1-3 were determined: Test Example (1), Processing Performance: The Mooney viscosity [ML(1+4)121℃] of the rubber composition was determined according to GB / T1232.1-2000 to characterize the flowability of the rubber composition at the processing temperature. The lower the viscosity, the better the processing performance. The results of the Mooney viscosity [ML(1+4)121℃] determination are shown in Table 1: Table 1 As shown in Table 1, the rubber composition prepared by this invention has good processing properties. Compared with Example 1, Comparative Example 1 did not use KH560 in the fiber modification step. The carboxyl-terminated liquid fluororubber could only adhere to the fiber surface through physical adsorption. This physical adsorption layer was easily peeled off in subsequent high-shear mixing, resulting in the loss of liquid fluororubber. The fiber surface was re-exposed and, due to its roughening, it underwent severe agglomeration, forming a rigid filler network that hindered the movement of molecular chains, leading to an increase in Mooney viscosity. In Comparative Example 2, the aramid fiber did not undergo any surface modification treatment. The fiber surface was smooth and chemically inert, and the interfacial bonding with the fluororubber matrix was extremely weak, resulting in increased Mooney viscosity. Under the shearing action of the stress test, the rubber molecular chains undergo interfacial slippage on the fiber surface, failing to effectively transfer stress to the fiber. Therefore, the flow resistance is small, and its Mooney viscosity is even lower than that of Comparative Example 1, which has a high viscosity due to severe filler agglomeration. However, the low viscosity comes at the cost of sacrificing interfacial bonding. Although it is beneficial for processing, it will damage the final mechanical properties and aging resistance of the composite material. Comparative Example 3 uses unmodified fumed silica. The nanoparticles have high surface energy and are prone to agglomeration to form a filler network, which restricts the movement of rubber molecular chains and leads to an increase in Mooney viscosity.
[0029] Test Example (2), Mechanical Properties: The rubber compositions obtained in Examples 1-3 and Comparative Examples 1-3 were poured into standard molds and vulcanized according to a uniform vulcanization process to prepare standard test strips. The vulcanization process included a first-stage vulcanization (120℃×15min) and a second-stage vulcanization (170℃×4h). Referring to GB / T528-2009, the tensile strength, elongation at break, and tear strength of the test strips were determined using a universal testing machine. The test results are shown in Table 2. Table 2 As shown in Table 2, the rubber composition prepared by this invention has good mechanical properties. Compared with Example 1, in Comparative Example 1, the fiber surface lacks the KH560 modified chemical bridging layer, and the fiber and matrix are only physically adsorbed, resulting in weak interfacial bonding. Under stress, the fiber is easily pulled out of the matrix, which cannot effectively transfer and disperse stress, leading to a decrease in the reinforcing and toughening effect. In Comparative Example 2, the untreated aramid fiber has gaps at the interface with the matrix and lacks chemical bonding. At the same time, without plasma activation, the fiber surface has few active groups, further weakening the interfacial bonding, resulting in low stress transfer efficiency and a decrease in tensile and tear strength. In Comparative Example 3, the unmodified fumed silica has poor dispersion in the matrix and easily forms stress concentration points. Although it has a certain reinforcing effect, it cannot participate in the network as a chemical crosslinking point like modified silica. Therefore, its nano-effect of reinforcing and toughening is not fully utilized, and the mechanical properties are also reduced.
[0030] Test Example (3), Heat Aging Resistance: The test specimens were placed in a 200℃ hot air aging chamber for 168 hours. The tensile strength and elongation at break after aging were tested. Based on the tensile strength and elongation at break measured in test example (2), the tensile strength retention rate and elongation at break retention rate were calculated to evaluate the long-term heat resistance stability of the material. The test results are shown in Table 3. Table 3 As shown in Table 3, the rubber composition prepared by this invention has good heat aging resistance. Compared with Example 1, in Comparative Example 1, the interface is only bonded by physical action. During high-temperature aging, the interface is more prone to debonding and damage due to thermal stress and molecular chain movement, resulting in an increase in internal defects and a sharp decline in macroscopic properties. In Comparative Example 2, the untreated fiber / matrix interface is weak, and high-temperature aging accelerates the damage of the interface region. In addition, due to the lack of stable chemical bonding, the integrity of the crosslinking network is relatively poor, resulting in a decrease in performance retention. In Comparative Example 3, the unmodified silica may migrate or agglomerate at high temperatures, destroying the already fragile physical crosslinking points. The stability of the chemical crosslinking network is also reduced due to the lack of anchoring effect of nanoparticles, thus the performance is significantly degraded.
[0031] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.
Claims
1. A method for preparing a high-toughness rubber composition, characterized in that, Includes the following steps: Step 1: Reaction of carboxyl-terminated liquid fluororubber with γ-(2,3-epoxypropoxy)propyltrimethoxysilane to obtain a modified liquid fluororubber solution; Step 2: Immerse the surface-modified aramid fibers in a modified liquid fluororubber solution and react to obtain modified aramid fibers; Step 3: Mix and stir the carboxyl-terminated liquid fluororubber, reinforcing filler, acid absorber, and processing aid, add modified aramid fiber, and continue mixing and stirring to obtain the composite rubber compound; Step 4: Add vulcanizing agent and crosslinking agent to the composite rubber compound, stir, and obtain the high-toughness fluororubber composition.
2. The method for preparing a high-toughness rubber composition according to claim 1, characterized in that, Step one specifically includes: Add carboxyl-terminated liquid fluororubber to acetone and stir to obtain mixture A; γ-(2,3-epoxypropoxy)propyltrimethoxysilane and triethylamine were added to acetone and stirred to obtain mixture B. Heat mixture B to a set temperature, and add mixture A dropwise under a nitrogen atmosphere. After the addition is complete, allow the reaction to proceed. After the reaction is complete, cool the mixture to obtain a modified liquid fluororubber solution.
3. The method for preparing a high-toughness rubber composition according to claim 2, characterized in that, The mass ratio of carboxyl-terminated liquid fluororubber in mixture A, γ-(2,3-epoxypropoxy)propyltrimethoxysilane in mixture B, and triethylamine in mixture B is 1:(0.4-0.6):(0.01-0.012); the reaction conditions are: reaction in a nitrogen atmosphere at a set temperature for 6-10 h. The set temperature is 95-100℃.
4. The method for preparing a high-toughness rubber composition according to claim 1, characterized in that, Step two specifically includes: Surface-modified aramid fibers were added to a modified liquid fluororubber solution, a catalyst was added, and the mixture was stirred to react. After the reaction was completed, the mixture was leached, washed, and dried to obtain modified aramid fibers. The mass ratio of surface-modified aramid fiber, modified liquid fluororubber solution, and catalyst is 10:(400-600):(3-5). The reaction conditions are a stirring speed of 200-400 r / min and a reaction temperature of 50-60℃ for 1.5-2.5 h. The catalyst is prepared by mixing deionized water and ethanol at a volume ratio of 1:(3-5).
5. The method for preparing a high-toughness rubber composition according to claim 4, characterized in that, The surface-modified aramid fiber is prepared by the following steps: First, the aramid fiber is cleaned and dried, and then plasma treated to obtain surface-modified aramid fiber. The plasma treatment conditions are as follows: in an air atmosphere, at a power of 50-100W, for a treatment time of 3-5 minutes.
6. The method for preparing a high-toughness rubber composition according to claim 1, characterized in that, In step three, the mass ratio of carboxyl-terminated liquid fluororubber, modified aramid fiber, reinforcing filler, acid absorber, and processing aid is 100:(15-25):(4-8):(1.5-3):(2-4). The mixing conditions are: mixing at a stirring speed of 200-400 r / min for 8-12 min, and continuing mixing at a stirring speed of 200-400 r / min for 25-35 min. The acid absorbent includes magnesium oxide; The processing aids include zinc stearate; The reinforcing filler includes epoxy-modified fumed silica.
7. The method for preparing a high-toughness rubber composition according to claim 6, characterized in that, The epoxy-modified fumed silica is prepared by the following steps: The dried fumed silica was added to ethanol and ultrasonically dispersed to obtain a silica suspension. γ-(2,3-epoxypropoxy)propyltrimethoxysilane was added to deionized water and stirred to hydrolyze, yielding a silane coupling agent solution. The silica suspension was mixed with a silane coupling agent solution and reacted. After the reaction was completed, the mixture was centrifuged, washed, and dried to obtain the epoxy-modified fumed silica. The mass ratio of fumed silica in the silica suspension to γ-(2,3-epoxypropoxy)propyltrimethoxysilane in the silane coupling agent solution is 1:(4-6), and the reaction is carried out under the condition of stirring at 60-80℃ for 2-4 hours.
8. The method for preparing a high-toughness rubber composition according to claim 1, characterized in that, In step four, the amount of vulcanizing agent added is 1.5-2.5% of the mass of the composite rubber compound, the amount of crosslinking aid added is 1-2% of the mass of the composite rubber compound, and the stirring conditions are: stirring at a speed of 200-300 r / min for 15-25 min under vacuum conditions. The vulcanizing agent includes 2,5-dimethyl-2,5-bis(tert-butylperoxy)hexane; The crosslinking aid includes triallyl isocyanurate.
9. A high-toughness rubber composition prepared by the method for preparing a high-toughness rubber composition according to any one of claims 1-8.
10. The application of the high-toughness rubber composition as described in claim 9 in a semiconductor sealing ring.