According to its curing temperature, silicone rubber can be divided into high temperature heating vulcanization (HTV) and room temperature vulcanization (RTV). High temperature rubber is mainly used to manufacture various silicone rubber products, while room temperature rubber is mainly used as adhesive, potting material or mold.
1. Heat vulcanized silicone rubber (HTV)
Thermal vulcanized silicone rubber (HTV) is the most important type of silicone products, methyl vinyl silicone rubber (VMQ) is the most important type of HTV, commonly known as high-temperature rubber. Methyl vinyl silicone rubber (raw rubber) is a colorless, odorless, non-toxic and mechanical impurities free rubber. Raw rubber is mixed with appropriate reinforcing agent, structural joint agent, curing agent and other additives as required, and then molded or extruded at elevated temperature, and then vulcanized into various finished products. The finished product has excellent electrical insulation, strong resistance to electric arc, corona and electric spark, good waterproof, moisture-proof, impact resistance, seismic resistance, psychological inertia, breathability and other functions.
It is mainly used in aviation, instruments, electronic appliances, sailing sea, metallurgy, machinery, automobile, medical and health and other parts. It can be used as sealing rings, gaskets, tubes, cables of various shapes, as well as human organs, blood vessels, breathable membranes, rubber molds, fine forging release agents, etc.
2. Room temperature vulcanized silicone rubber (RTV)
Room temperature vulcanized silicone rubber is generally of condensation type and addition type.
The condensation RTV silicone rubber is characterized by the condensation reaction between the silicon hydroxyl group and other active substances. It can be cross-linked to become an elastomer at room temperature. The products can be divided into single component packaging and two-component packaging. One component room temperature vulcanized silicone rubber (RTV-1 for short) is one of the primary products in condensed liquid silicone rubber. It is made of basic polymer, cross-linking agent, catalyst, filler and additive. The product is packed in a sealed hose, extruded during operation, and can be self vulcanized into an elastomer after contacting the air, which is very convenient for use. Vulcanized rubber can be used for a long time at (– 60~+200 ℃) temperature limit, has excellent electric cut-off gas margin function and chemical invariance, can withstand water, ozone, weather aging, and has excellent adhesion to a variety of metal and non-metallic materials. It is mainly used for coating various electronic components and electrical equipment, and the enveloping data has insulation, moisture-proof and shockproof effects; As the surface maintenance data of semiconductor devices; It can also be used as sealing filler and elastic adhesive.
The addition molding room temperature adhesive takes linear polysiloxane with vinyl as the base adhesive, and hydrosiloxane as the crosslinking agent. It becomes an elastomer when the catalyst reacts at room temperature to medium temperature. It has excellent heat resistance, hydrophobicity and electrical insulation. Due to the introduction of active terminal groups, it has excellent physical and mechanical functions, especially in tensile strength, relative elongation and tear strength. It is suitable for a variety of vulcanization methods, such as radiation vulcanization, peroxide vulcanization and addition vulcanization. It is widely used in heat resistance, moisture resistance, electrical insulation, high strength silicone rubber products, etc.
Post time: Nov-11-2022
