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Silicone Rubber
Aug 17, 2018

1. Room temperature vulcanized silicone rubber

Room temperature vulcanized silicone rubber (RTV) is a new type of silicone elastomer that was introduced in the 1960s. The most remarkable feature of this rubber is that it can be cured in situ without heating or pressure, and it is extremely convenient to use. Therefore, it has quickly become an important part of the entire silicone product. At room temperature vulcanized silicone rubber has been widely used as an adhesive, sealant, protective coating, potting and molding material, and has its use in various industries.


Classification

Room temperature vulcanized silicone rubber can be divided into one-component and two-component room temperature vulcanized silicone rubber according to its packaging method. According to the vulcanization mechanism, it can be divided into condensation type and addition molding. Therefore, room temperature vulcanized silicone rubber can be divided into three types according to composition, vulcanization mechanism and use process, namely single-component room temperature vulcanized silicone rubber, two-component condensation type room temperature vulcanized silicone rubber and two-component addition type room temperature vulcanized silicone rubber. . These three series of room temperature vulcanized silicone rubbers have their own characteristics: the advantages of one-component room temperature vulcanized silicone rubber are ease of use, but the deep curing speed is difficult; the advantage of two-component room temperature vulcanized silicone rubber is that it does not exotherm when cured. The shrinkage rate is small, no expansion, no internal stress, curing can be carried out simultaneously in the interior and the surface, and can be vulcanized in depth; the vulcanization time of the formed room temperature vulcanized silicone rubber is mainly determined by the temperature, therefore, the vulcanization rate can be controlled by the adjustment of the temperature. .


One-component room temperature vulcanized silicone rubber

The vulcanization reaction of the one-component room temperature vulcanized silicone rubber is vulcanized into an elastomer by acting on moisture in the air. The single-component room temperature vulcanized silicone rubber may be of various types such as deacidification type, depurination type, dealcoholization type, deamination type, deamidation type and deketone type, depending on the chain agent. The vulcanization time of the one-component room temperature vulcanized silicone rubber depends on the vulcanization system, temperature, humidity, and thickness of the silicone rubber layer. Increasing the temperature and humidity of the environment can accelerate the vulcanization process. Under typical environmental conditions, generally 15 to 30 minutes, the surface of the silicone rubber may be non-tacky, and a layer of 0.3 cm thick may be cured within one day. The depth and strength of curing will gradually increase in about three weeks.