(1) Silicone base polymer

The basic component of the addition type liquid silicone rubber is the silicone base polymer, which is mainly a polydiorganosiloxane containing 2 or more silicon-vinyl groups. It is usually a linear silicone polymer with a vinyl group at each end of the polymer chain, and some contain a small amount of silicon-vinyl link in the middle of the polymer chain. A typical base polymer that is used the most is α,ω-divinyl polydimethylsiloxane, or simply vinyl silicone oil.

(2) Cross-linking agent

The basic component cross-linking agent of the addition type liquid silicone rubber is an organosiloxane oligomer containing 3 or more silicon-hydrogen bonds, that is, a low-viscosity methyl hydrogen-containing silicone oil.

(3) Catalyst

Although there are many catalysts that can initiate hydrosilation reaction, the catalysts that can be used for addition type liquid silicone rubber are only Group VIII transition metal elements and their compounds or complexes, among which platinum catalysts have the highest catalytic efficiency.

Direct application of platinum catalysts can catalyze silicone rubber to complete the hydrosilylation vulcanization reaction at room temperature; by adding an appropriate amount of inhibitor to the platinum catalyst, a catalyst for medium temperature vulcanization can be prepared.

(4) Filling and reinforcing materials

The mechanical strength of the vulcanized silicone rubber obtained by simply cross-linking the silicone base polymer and the hydrogen-containing silicone oil is not high. In order to improve the mechanical strength of the vulcanized silicone rubber, it is necessary to add reinforcing fillers to the silicone rubber system. The most commonly used reinforcing fillers are fumed silica, precipitated silica, quartz powder, etc. If you want to obtain colorless and transparent silicone rubber, you need to use methyl vinyl MQ silicone resin as a transparent reinforcing filler.

(5) Other additives

In order to adjust the process performance or performance of silicone rubber, different additives are required. To formulate the color of the rubber compound, it is necessary to use pigments or dyes as colorants; in order to improve the heat resistance of silicone rubber, it is necessary to add heat-resistant additives; in order to improve the adhesive properties of silicone rubber, auxiliary components such as tackifiers should be introduced.