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CN-121991513-A - High-strength and high-toughness wear-resistant flame-retardant silicone rubber composite material and preparation method thereof

CN121991513ACN 121991513 ACN121991513 ACN 121991513ACN-121991513-A

Abstract

The invention relates to the technical field of rubber, in particular to a high-strength and high-toughness wear-resistant flame-retardant silicone rubber composite material and a preparation method thereof. The composite material takes vinyl-terminated polydimethylsiloxane and vinyl-terminated (diphenyl siloxane) -dimethylsiloxane copolymer as matrixes, a flame-retardant structure is chemically bonded to a crosslinked network by introducing a reactive phosphorus-containing siloxane crosslinking agent, and an amino/alkenyl silane double-path modified hydroxylated boron nitride nano-sheet is adopted to cooperate with para-aramid pulp to construct a multidimensional reinforcing system. The preparation method effectively avoids catalyst poisoning through a time sequence process of pre-reaction and then solidification, and ensures that the filler is uniformly dispersed and strongly combined with the interface. The material has high mechanical strength, excellent wear resistance and durable flame retardance, and is particularly suitable for sealing element application under the working condition of long-term vibration friction.

Inventors

  • HU HAIBO

Assignees

  • 东莞市华奇密封件有限公司

Dates

Publication Date
20260508
Application Date
20260305

Claims (10)

  1. 1. The high-strength and high-toughness wear-resistant flame-retardant silicone rubber composite material is characterized by being prepared from the following raw materials in parts by mass: 750 parts of vinyl-terminated polydimethylsiloxane; 150 parts of vinyl-terminated (diphenylsiloxane) -dimethylsiloxane copolymer; 8-15 parts of aminosilane grafted hydroxylated boron nitride nano sheet; 18-35 parts of reactive phosphorus-containing siloxane crosslinking agent; 220-260 parts of hydrophobic fumed silica; 16-30 parts of alkenyl silane grafted hydroxylated boron nitride nano sheet; 50-80 parts of para-aramid pulp; 0.65-1.00 parts of a platinum-divinyl tetramethyl disiloxane complex xylene solution; 0.16-0.25 part of 1-ethynyl-1-cyclohexanol; The reactive phosphorus-containing siloxane cross-linking agent is prepared by reacting (methyl hydrogen siloxane) -dimethyl siloxane copolymer with allyl glycidyl ether under the catalysis of platinum to obtain an epoxy functional silicon hydrogen siloxane intermediate, and then reacting the epoxy functional silicon hydrogen siloxane intermediate with 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.
  2. 2. The high-strength and high-toughness wear-resistant flame-retardant silicone rubber composite material according to claim 1, wherein the mass ratio of (methyl hydrogen siloxane) -dimethyl siloxane copolymer, allyl glycidyl ether and 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in the preparation raw materials of the reactive phosphorus-containing siloxane cross-linking agent is 200:40:40.
  3. 3. The high-strength and high-toughness wear-resistant flame-retardant silicon rubber composite material according to claim 1 is characterized in that the alkenyl silane grafted hydroxylated boron nitride nanosheets are obtained by grafting vinyl trimethoxy silane onto hydroxylated boron nitride nanosheets, and the amino silane grafted hydroxylated boron nitride nanosheets are obtained by grafting 3-aminopropyl triethoxy silane onto hydroxylated boron nitride nanosheets.
  4. 4. The high-strength and high-toughness wear-resistant flame-retardant silicon rubber composite material according to claim 3, wherein the mass ratio of vinyl trimethoxy silane to hydroxylated boron nitride nano-sheets in the preparation raw material of alkenyl silane grafted hydroxylated boron nitride nano-sheets is 8:25, and the mass ratio of 3-aminopropyl triethoxy silane to hydroxylated boron nitride nano-sheets in the preparation raw material of aminosilane grafted hydroxylated boron nitride nano-sheets is 10:25.
  5. 5. The high-strength, high-toughness, wear-resistant, flame-retardant silicone rubber composite according to claim 1, wherein the 750 parts by mass of vinyl-terminated polydimethylsiloxane comprises 500 parts by mass of a first vinyl-terminated polydimethylsiloxane having a viscosity of 60000cSt and a vinyl equivalent of 0.018 to 0.020eq/kg, and 250 parts by mass of a second vinyl-terminated polydimethylsiloxane having a viscosity of 1000cSt and a vinyl equivalent of 0.07 to 0.10eq/kg, the vinyl-terminated (diphenyl-siloxane) -dimethylsiloxane copolymer having a viscosity of 10000cSt, and the (methyl-hydrosiloxane) -dimethylsiloxane copolymer having a viscosity of 25 to 35cSt.
  6. 6. The high strength and toughness wear-resistant flame-retardant silicone rubber composite material according to claim 1, wherein the para-aramid pulp is derived from tepralone TAPARAN, model 1427.
  7. 7. The high strength and toughness wear resistant flame retardant silicone rubber composite according to claim 1, wherein the platinum-divinyl tetramethyl disiloxane complex xylene solution has a platinum content of 1.5% -2.5%.
  8. 8. A method of preparing the high strength and toughness abrasion resistant flame retardant silicone rubber composite according to any one of claims 1-7, comprising the steps of: (1) Mixing vinyl-terminated polydimethylsiloxane and vinyl-terminated (diphenyl siloxane) -dimethylsiloxane copolymer in a vacuum planetary stirring kettle, adding aminosilane grafted hydroxylated boron nitride nano sheet, and mixing; (2) Adding a reactive phosphorus-containing siloxane crosslinking agent, mixing, heating to 70-90 ℃ and maintaining for 60-120min to perform pre-reaction, defoaming and cooling to obtain pre-reaction masterbatch; (3) Sequentially adding hydrophobic fumed silica, alkenyl silane grafted hydroxylated boron nitride nano sheet and para-aramid pulp, mixing and defoaming to obtain a final mixed sizing material; (4) And cooling the final mixed sizing material to 25 ℃, adding a platinum-divinyl tetramethyl disiloxane complex xylene solution and 1-ethynyl-1-cyclohexanol, mixing, and then performing compression molding and post-curing to obtain the high-strength and high-toughness wear-resistant flame-retardant silicone rubber composite material.
  9. 9. The high-strength and high-toughness wear-resistant flame-retardant silicone rubber composite material according to claim 8, wherein in the step (3), hydrophobic fumed silica, alkenyl silane grafted hydroxylated boron nitride nano-sheets and para-aramid pulp are dried for 4 hours at 120 ℃ respectively, and the hydrophobic fumed silica is added in 4 times under the condition that a pre-reaction masterbatch is kept at 40 ℃, mixed for 10 minutes at 800rpm after each addition, and defoamed for 5 minutes at-90 kPa.
  10. 10. The high-strength and high-toughness wear-resistant flame-retardant silicone rubber composite material according to claim 8, wherein the molding temperature in the step (4) is 110-130 ℃, the pressure is 10MPa, the time is 20-25min, and the post-curing temperature is 175-190 ℃ and the time is 2h.

Description

High-strength and high-toughness wear-resistant flame-retardant silicone rubber composite material and preparation method thereof Technical Field The invention relates to the technical field of rubber, in particular to a high-strength and high-toughness wear-resistant flame-retardant silicone rubber composite material and a preparation method thereof. Background Because of its excellent heat resistance and elasticity, silicone rubber materials are widely used in the sealing field, but traditional high flame retardant silicone rubber is mostly introduced by adopting a small molecular phosphorus flame retardant or a halogen flame retardant through a physical blending mode. The additive flame retardant has poor compatibility with a silicon rubber matrix, is easy to migrate and precipitate under long-term use or high-temperature environment, reduces flame retardant efficiency, and can form a weak bonding area at an interface, so that mechanical properties such as tensile strength and tear strength are obviously deteriorated. In addition, migrating flame retardant components may contaminate the surrounding environment or affect the long term stability of the seal, especially under dynamic friction conditions, weak interfacial bonding may exacerbate wear, causing the surface of the material to be prone to cracking and flaking, further shortening the service life. Along with the improvement of the performance requirements of sealing elements in application scenes, such as rail transit fire-resistant sealing strips and battery pack vibration friction sealing, materials are required to have high strength and toughness, low abrasion and lasting flame retardant properties. However, the limitation of the added flame retardant in the prior art causes the silicone rubber to have trade-off between flame retardance and mechanical properties, namely, the increased use amount of the flame retardant can improve the flame retardance grade but can sacrifice the flexibility and wear resistance of the material, and when the high mechanical properties are pursued, the flame retardance effect is not durable due to uneven dispersion or interface defects of the flame retardant. Particularly under the condition of high load or continuous friction, the problems of abrasion aggravation and flame retardant property attenuation of the traditional silicone rubber are more remarkable, and the requirement of engineering application on long-term reliability cannot be met. Therefore, developing a new scheme capable of fundamentally solving the problems of migration, interface weakening and performance synergy of the flame retardant becomes a technical bottleneck in the field. Disclosure of Invention In view of the above, the invention aims to provide a high-strength and high-toughness wear-resistant flame-retardant silicone rubber composite material and a preparation method thereof, so as to solve the problems that the conventional high-flame-retardant silicone rubber depends on the physical blending of an additive flame retardant, is easy to cause component migration, interface weakening and mechanical property reduction, and is difficult to meet the requirement of long-term flame retardance of a sealing member under a high wear-resistant working condition. Based on the purposes, the invention provides a high-strength and high-toughness wear-resistant flame-retardant silicone rubber composite material which is prepared from the following raw materials in parts by mass: 750 parts of vinyl-terminated polydimethylsiloxane; 150 parts of vinyl-terminated (diphenylsiloxane) -dimethylsiloxane copolymer; 8-15 parts of aminosilane grafted hydroxylated boron nitride nano sheet; 18-35 parts of reactive phosphorus-containing siloxane crosslinking agent; 220-260 parts of hydrophobic fumed silica; 16-30 parts of alkenyl silane grafted hydroxylated boron nitride nano sheet; 50-80 parts of para-aramid pulp; 0.65-1.00 parts of a platinum-divinyl tetramethyl disiloxane complex xylene solution; 0.16-0.25 part of 1-ethynyl-1-cyclohexanol; The reactive phosphorus-containing siloxane cross-linking agent is prepared by reacting (methyl hydrogen siloxane) -dimethyl siloxane copolymer with allyl glycidyl ether under the catalysis of platinum to obtain an epoxy functional silicon hydrogen siloxane intermediate, and then reacting the epoxy functional silicon hydrogen siloxane intermediate with 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide. Preferably, the mass ratio of the (methyl hydrosiloxane) -dimethylsiloxane copolymer, the allyl glycidyl ether and the 9, 10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide in the preparation raw materials of the reactive phosphorus-containing siloxane cross-linking agent is 200:40:40. Preferably, the (methylhydrosiloxane) -dimethylsiloxane copolymer has a viscosity of 25 to 35cSt. Preferably, the alkenyl silane grafted hydroxylated boron nitride nanosheets are obtained by grafting vinyl trimethoxy silane to hydroxylated boron ni