What's RTV

What’s RTV

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 and pressure at room temperature, and it is extremely convenient to use. Therefore, it has become an important part of the whole silicone product as soon as it comes out. RTV silicone rubber is now widely used as adhesives, sealants, protective coatings, potting and molding materials, and has its uses in all walks of life. RTV silicone rubber is known as liquid silicone rubber due to its low molecular weight, and its physical form is usually flowable fluid or viscous paste. 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. 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, room temperature vulcanized silicone rubber can be divided into three types according to the composition, vulcanization mechanism and use process, namely single-component room temperature vulcanization silicone rubber, two-component condensation type room temperature vulcanization silicone rubber and two-component addition type room temperature vulcanization silicone rubber .

Addition type room temperature vulcanized silicone rubber is a polysiloxane containing alkenyl and hydrogen side groups (or end groups), because when vulcanized, it is often slightly higher than room temperature (50-150 ℃) to obtain good performance. Therefore, it is also called low temperature vulcanized silicone rubber (LTV).

These three series of RTV silicone rubbers 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 is possible; the vulcanization time of addition type RTV silicone rubber is mainly determined by the temperature, so the vulcanization can be controlled by adjusting the temperature.