Silicone rubber is one of the largest and most widely used silicone products. After vulcanization, silicone rubber has excellent high and low temperature resistance, weatherability, hydrophobicity, electrical insulation, physiological inertia and other characteristics.

Main properties and applications of silicone rubber products: according to its curing temperature, silicone rubber can be divided into high temperature (heating) curing type and room temperature curing type. High temperature rubber is mainly used for manufacturing various silicone rubber products, while room temperature rubber is mainly used as adhesive, pouring material or mold.

Heat vulcanized silicone rubber (HTV)

Heat cured silicone rubber (HTV) is one of the most important silicone products. Methyl vinyl silicone rubber (VMQ) is the main variety of HTV, commonly known as high temperature rubber. Methyl vinyl silicone rubber (raw rubber) is colorless, odorless, non-toxic, and no mechanical impurities. Raw rubber is mixed with appropriate reinforcing agent, structure control agent, curing agent and other additives as needed, and then heated, molded or extruded, and then made into various products by two-stage vulcanization. Its products have excellent electrical insulation, arc resistance, corona resistance, electric spark ability, waterproof, moisture-proof, impact resistance, earthquake resistance, physiological inertia, air permeability and other properties. It is mainly used in aviation, instruments, electronic and electrical appliances, navigation, metallurgy, machinery, automobile, medical and health departments. It can be used as sealing rings, gaskets, pipes, cables of various shapes, as well as human organs, blood vessels, breathable films, rubber molds, mould release agents for precision casting, etc.

Room temperature vulcanized silicone rubber (RTV)
RTV silicone rubber generally includes condensation type and addition type. The addition molding room temperature adhesive is based on linear polysiloxane with vinyl group, with hydrosiloxane as crosslinking agent, and crosslinked at room temperature to medium temperature in the presence of catalyst. It has good heat resistance, hydrophobicity and electrical insulation. At the same time, due to the introduction of active end groups, it has excellent physical and mechanical properties, 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.

Condensation Type RTV silicone rubber is characterized by the condensation reaction between silicone hydroxyl and other active substances, which can be crosslinked into elastomer at room temperature. The products are divided into two forms: one component packaging and two-component packaging. One component RTV-1 is one of the main products of condensed liquid silicone rubber. It is usually made up of base polymer, crosslinking agent, catalyst, filler and additive. The product is packed in a sealed hose and extruded when used. It can be vulcanized into elastomer by itself after contacting with air, so it is very convenient to use. Vulcanizate can be used for a long time in (- 60 ～ + 200 ℃) temperature range, with excellent electrical insulation performance and chemical stability, water resistance, ozone resistance, weather aging resistance, and good adhesion to a variety of metal and non-metal materials. It is mainly used as coating material for various electronic components and electrical equipment, with insulation, moisture-proof and shockproof functions, as surface protection material for semiconductor devices, as sealing filler and elastic adhesive, etc.

Two component RTV-2 rubber is not as convenient as RTV-1 rubber in use, but its component proportion is varied. One variety can get vulcanized products with various specifications and properties, and it can also be deeply vulcanized. Therefore, it is widely used for insulation, packaging, caulking, sealing and anti-corrosion in electronic and electrical appliances, automobile, machinery, construction, textile, chemical, light industry, printing and other industries The material of damp, anti-seismic and roller. In addition, RTV-2 has excellent demoulding property, so it is widely used in the reproduction and manufacturing of cultural relics, handicrafts, toys, electronic appliances, mechanical parts, etc.

One of the typical applications of silicone sealant is glass curtain wall. The glass and aluminum frame are bonded with silicone structural adhesive as exterior wall material, and the expansion joint is waterproof and sealed with silicone weathering adhesive. Other applications include the peripheral sealing of aluminum alloy doors and windows and plastic steel doors and windows, the sealing of glass installation and moving slot, rivets and fixed screws; the waterproof sealing of sanitary ware in kitchen, bathroom and toilet, and between countertops, walls and furniture; the sealing of aquarium, ceiling, metal roof, window, counter, wallboard and color steel plate; and the sealing of high-grade Waterproof caulking and sealing between highway plates.

In addition to building sealant, RTV also includes sealing materials for aerospace, nuclear power station, electronics, machinery, automobile and other industries, silicone sealing materials for electronic components, silicone mold adhesive for soft mold materials, etc. The demand for these varieties is relatively small, but they are indispensable in many occasions.