Room temperature vulcanized silicone rubber (RTV) is a new type of silicone elastomer that came out in the 1960s. The most notable feature of this rubber is that it can be cured in situ without heating at room temperature, such as pressing, and it is extremely convenient to use. Therefore, as soon as it came out, it quickly became an important part of the whole silicone product. RTV silicone rubber is now widely used as adhesives, sealants, protective coatings, potting and molding materials, and has its uses in various industries.

RTV silicone rubber is known as liquid silicone rubber due to its low molecular weight. Its physical form is usually a flowable fluid or a viscous paste, and its viscosity is between 100 and 1,000,000 centistokes. According to the requirements of use, the pre-vulcanization compound can be formulated into a self-leveling pouring material or a non-flowing but scratchable putty. The filler used in room temperature vulcanized silicone rubber is similar to that of high temperature vulcanized silicone rubber, and it is reinforced with white carbon black, so that the vulcanized rubber has a breaking strength of 10-60 kg/cm2. Adding different additives can make the rubber compound have different specific gravity, hardness, strength, fluidity and thixotropy, and make the vulcanizate have various special properties such as flame retardant, electrical conductivity, thermal conductivity, and ablation resistance.

RTV silicone rubber can be divided into one-component and two-component RTV silicone rubber according to its packaging method, and can be divided into condensation type and addition type according to the vulcanization mechanism. Therefore, RTV silicone rubber can be divided into three types according to the composition, vulcanization mechanism and use process, namely, one-component RTV silicone rubber, two-component condensation type RTV silicone rubber and two-component addition type RTV silicone rubber. .

The raw rubber of one-component and two-component condensation type RTV silicone rubber is α,ω-dihydroxy polysiloxane; the addition type RTV silicone rubber contains alkenyl and hydrogen side groups (or end groups) Polysiloxane is also called low temperature vulcanized silicone rubber (LTV) because it can achieve good curing effect at a temperature slightly higher than room temperature (50-150℃) during curing.

These three series of RTV silicone rubber have their own advantages and disadvantages: the advantage of one-component RTV silicone rubber is that it is easy to use, but the deep curing speed is difficult; the advantage of two-component RTV silicone rubber is that it does not exotherm during curing. , The shrinkage rate is very small, there is no expansion, no internal stress, curing can be carried out at the same time inside and on the surface, and deep vulcanization can be performed; the vulcanization time of addition type RTV silicone rubber is mainly determined by the temperature, so the temperature adjustment can be used to control its vulcanization speed.