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CN-121991514-A - Fluorosilicone rubber composition with high tearing resistance and preparation process thereof

CN121991514ACN 121991514 ACN121991514 ACN 121991514ACN-121991514-A

Abstract

The invention relates to the technical field of fluorosilicone rubber, and particularly discloses a fluorosilicone rubber composition with high tear resistance and a preparation process thereof. The composition comprises the following raw materials, by weight, 80-120 parts of methyl vinyl fluorosilicone rubber raw rubber, 40-50 parts of reinforcing filler, 5-8 parts of siloxane polymer, 1-2 parts of auxiliary vulcanizing agent, 1-2 parts of vulcanizing agent, 1-3 parts of heat-resistant additive, 1-2 parts of release agent and 1-4 parts of colorant. The methyl vinyl fluorosilicone rubber is an oil-resistant and temperature-resistant matrix, and the siloxane polymer has the functions of lubricating, participating in crosslinking and reinforcing a network, forming a flexible micro-area and resisting tearing, and realizes the balance of all performances together with other assistants.

Inventors

  • Rong Tingen

Assignees

  • 开信高分子材料(浙江)有限公司

Dates

Publication Date
20260508
Application Date
20260313

Claims (10)

  1. 1. The fluorosilicone rubber composition with high tearing resistance is characterized by comprising, by weight, 80-120 parts of methyl vinyl fluorosilicone rubber raw rubber, 40-50 parts of reinforcing filler, 5-8 parts of siloxane polymer, 1-2 parts of auxiliary vulcanizing agent, 1-2 parts of vulcanizing agent, 1-3 parts of heat-resistant additive, 1-2 parts of release agent and 1-4 parts of colorant.
  2. 2. The fluorosilicone rubber composition with high tear resistance according to claim 1, wherein the reinforcing filler is fumed silica.
  3. 3. The fluorosilicone rubber composition having high tear resistance according to claim 1, wherein the co-vulcanizing agent is triallyl isocyanurate.
  4. 4. The fluorosilicone rubber composition having high tear resistance according to claim 1, wherein the vulcanizing agent is 2, 5-dimethyl-2, 5-di (t-butylperoxy) hexane.
  5. 5. The fluorosilicone rubber composition having high tear resistance according to claim 1, wherein the heat resistant additive is nano cerium oxide.
  6. 6. The fluorosilicone rubber composition having high tear resistance according to claim 1, wherein the mold release agent is calcium stearate.
  7. 7. The fluorosilicone rubber composition with high tear resistance according to claim 1, wherein the colorant is titanium white.
  8. 8. The fluorosilicone rubber composition with high tear resistance according to claim 1, wherein the preparation method of the siloxane polymer comprises the steps of: adding alkenyl siloxane and dodecyl trimethoxy silane into a solvent, dropwise adding a hydrochloric acid solution at 20-30 ℃, heating and stirring for 2-4 hours, cooling, adding hexamethyldisilazane for end capping, heating and stirring for 3-5 hours, and performing reduced pressure distillation after the reaction is finished to obtain a siloxane polymer.
  9. 9. The fluorosilicone rubber composition having high tear resistance according to claim 8, wherein the mass ratio of the alkenylsiloxane to dodecyltrimethoxysilane, hydrochloric acid, hexamethyldisilazane is 1:0.5-1:0.0005-0.001:0.1-0.5.
  10. 10. Process for the preparation of a fluorosilicone rubber composition having high tear resistance according to any one of claims 1 to 9, comprising the steps of: X1, carrying out roll-in-roll plasticating on raw methyl vinyl fluorosilicone rubber, then adding a siloxane polymer, uniformly mixing, then adding fumed silica and a heat-resistant additive in batches, fully mixing until the mixture is completely dispersed, adding a release agent and a colorant, uniformly mixing, and then discharging to obtain a section of rubber compound, standing and curing; And X2, carrying out back refining on the first-stage rubber, adding a vulcanization aid and a vulcanizing agent, rapidly and uniformly mixing, discharging slices, placing the mixed rubber into a mold for compression molding vulcanization, and then carrying out second-stage vulcanization in an oven to obtain the high-tearing-resistance fluorosilicone rubber composition.

Description

Fluorosilicone rubber composition with high tearing resistance and preparation process thereof Technical Field The invention relates to the technical field of fluorosilicone rubber, in particular to a fluorosilicone rubber composition with high tear resistance and a preparation process thereof. Background Fluorosilicone rubber (fluorine-containing polysiloxane) is a polymer which takes-Si-O-as a main chain and has the side chain substituted by fluorine-containing organic groups, and has the double excellent characteristics of organosilicon materials and organic fluorine materials. The main chain-Si-O-structure endows the material with typical inorganic material characteristics including stable performance in a wide temperature range, excellent high and low temperature resistance and good electrical insulation caused by low dielectric constant, and the fluorine-containing organic side chain endows the material with outstanding high molecular material characteristics, including strong chemical stability, excellent solvent corrosion resistance and remarkable hydrophobic and oleophobic surface performance. The dual characteristics of the material are derived from two core mechanisms, namely that a main chain structure formed by silicon-oxygen bonds can form a rigid framework to ensure the structural stability of the material in an extreme environment, and a fluorine atom in a fluorine-containing organic side chain has extremely high electronegativity and can form a compact negative charge shielding layer around a connected carbon chain, so that the attack of a nucleophilic reagent can be effectively blocked to improve the chemical stability, and the surface energy of the material can be greatly reduced to realize the hydrophobic and oleophobic effects. Although the fluorosilicone rubber combines the advantages of the fluorosilicone rubber and the silicone rubber and is excellent in many properties, the mechanical strength after vulcanization is low, in particular, the tear strength. This is due to the inherent characteristics of its molecular structure and cross-linked network. First, the main chain of the fluorosilicone rubber is a linear structure formed by-Si-O-bonds, and the structure endows the material with excellent high and low temperature resistance, but the molecular chain is large in flexibility and low in entanglement degree of chain segments, the chain segments are easy to slip under the action of external force, and the stress is difficult to effectively disperse. Secondly, the fluorine-containing side chains have larger steric hindrance, which weakens Van der Waals force and interaction between molecular chains, and leads to insufficient cohesive force inside the polymer matrix. Thirdly, the crosslinking network formed by the conventional vulcanization system has the problems of low crosslinking density and uneven distribution of crosslinking points, and when the material is subjected to tearing force, stress is easily concentrated at a few crosslinking points or defects, so that chain segment fracture and crack expansion are initiated, and finally the material is poor in tearing strength. CN109679354a discloses a high tear resistance fluorosilicone rubber composition and a preparation method thereof, and belongs to the technical field of rubber. The fluorosilicone rubber composition consists of fluorosilicone rubber 100 weight portions, fumed silica 40-60 weight portions, fine fluorine resin powder 3-5 weight portions, whisker 5-10 weight portions, vulcanizing agent 0.5-1.5 weight portions and structure controlling agent 3-5 weight portions. The prepared fluorosilicone rubber composition not only has excellent tear resistance at room temperature and high temperature, but also can effectively improve the molding qualification rate of products. In addition, the invention also provides a corresponding preparation method, which comprises two scientific and reasonable steps, is simple and easy to operate and is convenient for industrialized application. CN108587186a relates to a modified white carbon black and a preparation method thereof, and simultaneously protects the application of the modified white carbon black in fluorosilicone rubber, belonging to the technical field of inorganic powder filler modification. The invention aims to solve the technical bottleneck that the high strength and low viscosity of the material are difficult to be simultaneously considered when the white carbon black modified fluorosilicone rubber is used in the prior art. The modified white carbon black comprises, by weight, 100 parts of white carbon black and 5-20 parts of a modifier, wherein the modifier is silane with a fluorine-containing silicon structure or siloxane with a fluorine-containing silicon structure. The modified white carbon black is mainly applied to the modification treatment of the fluorosilicone rubber, and can obviously reduce the viscosity of a rubber system and improve the processing technology p