Silicon rubber is a kind of polymer elastic material with both inorganic and organic properties. Its main molecular chain is composed of silicon atom and oxygen atom alternately (- Si-O-Si -). The side chain is hydrocarbon or substituted hydrocarbon organic group connected with silicon atom. This group can be methyl, unsaturated vinyl (mole fraction generally not more than 01005) or other organic groups This low unsaturation molecular structure makes silicone rubber have excellent heat aging resistance, weather aging resistance, UV and ozone corrosion resistance. These structural characteristics make the vulcanizate soft and elastic, but the physical properties are poor.
Silicone rubber was developed in the 1940s, and dimethyl silicone rubber was the first variety studied abroad. Around 1944, it was put into production by Dow Corning company and general electric company respectively. In the early 1960s, the research was successful and put into industrial production. At present, in addition to China, there are more than 1000 varieties and brands in the United States, Britain, Japan, the former Soviet Union and Germany.
Silicone rubber has unique comprehensive properties, especially the biocompatibility of silicone rubber is a key characteristic. It has been successfully used in other rubber ineffective occasions, solved many technical problems, and met the needs of modern industry and daily life. Like other rubbers, silicone rubber can be processed into various profiles, silica gel tubes, silica gel strips, silica gel rollers, silica gel cloth and other silica gel products; RTV silicone rubber can be applied in large area on site and is easy to use
(1) Automobile industry
The application of silicone rubber in the automotive industry is growing rapidly. Silicone rubber (especially silicone rubber with various characteristics) can resist the erosion of fuel and lubricating oil, improve the performance of automobile components and reduce maintenance costs. It can be used in automobile ignition wire, spark plug protective cover, hose for heating and radiator, muffler lining, battery connector and refueling pump made of fluorosilicone rubber. With the development of vehicle electronic electrification, RTV silicone rubber is widely used as sealant for electronic parts, electrical assembly parts, windshield glass, car body seal and reflector.、
(2) Electronic and electrical industry
Electronic and electrical industry is a field where silicone rubber is used as insulation material earliest and has a large demand. Silicone rubber is mainly used for TV anode cover, high-voltage protection cover, high-voltage outgoing line, refrigerator defroster wire, power or signal transmission wire and cable, etc. Insulators made of silicone rubber will be widely used in transmission lines, especially in EHV lines, instead of ceramic products.
Conductive silicone rubber is used in electrical contact parts of electronic computers, telephones and other instruments and liquid crystal display contacts. Flame retardant and radiation resistant silicone rubber wires and cables are widely used in atomic power stations. Silicone rubber heating sheet and heating belt are used to control the working temperature of various precision instruments and oil pipelines. They are used as heating blanket for physiotherapy hot compress in medical treatment. Room temperature vulcanized silicone rubber can be used as sealing material for waterproof, moisture-proof and shockproof.
Silicone rubber has been widely used in dishwasher and washing machine pump seal because of its heat-resistant detergent performance. Silicone rubber is very suitable for use as gaskets in coffee pots, electric fryers and steam irons. The earphone ear and head pad is made of silicone rubber, which can eliminate external noise and is soft and comfortable.
(3) Aerospace Industry
Silicone rubber is an indispensable high-performance material in aerospace industry. It can withstand the ultra-cold of space and the scorching heat of re-entry atmosphere, prolong the service life of aircraft parts, reduce maintenance costs and reduce accidents. It is mainly used for hole seal, electric joint, sealing switch, dust and waterproof cover, gasket, O-type sealing ring of jet engine and hydraulic device, oxygen mask, regulating diaphragm, hot air duct and radar wireless shock absorber, etc. Scorch resistant silicone rubber is suitable for coating rocket fuel valve, power source cable and rocket launching well cover to avoid being burned by rocket jet. RTV silicone rubber can be used as airtight sealing, window frame sealing, shockproof and moisture-proof potting materials.
(4) Construction industry
Silicone rubber has good weather resistance and workability, and has been widely used in the construction industry as a bonding sealant, surpassing other types of sealants. In recent years, low modulus and high elongation two-component sealant has been developed, which is used for large-scale components such as concrete prefabricated parts and curtain walls with large joint movement. It is also used to seal the joints of the room temperature vulcanized rubber tile and the bathroom furniture. With the decrease of rubber price in the future, the application scope will be further expanded, such as replacing asphalt and chloroprene rubber in the application of highway joints. High temperature vulcanized silicone rubber sponge strips are used as sealing fillers for doors and windows of buildings.
(5) Medical field
Silicone rubber has good biocompatibility, small reaction to the body, stable performance, low blood coagulation, can withstand high temperature and high pressure for many times cooking, and can be processed into various shapes of products, such as silicone film, silicone sponge, silicone balloon, is currently the most widely used material in medicine.
(6) Other areas
In addition to the various applications mentioned above, the application of silicone rubber in the fields of textile, printing, machinery, plastics, chemistry, papermaking, food and cosmetics has also increased significantly. A typical product is a roller made of silicone rubber, which is used for heat setting, embossing, calendering and fixing of photocopiers for fabrics and plastics. The modified atmosphere window made of silicone rubber film has been used to store fruits and vegetables. In addition, silicone rubber has been used as sealing material in high temperature textile equipment and equipment with high concentration of aChinaali, sodium hypochlorite and hydrogen peroxide.
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