Addition type liquid silicone rubber is based on linear polysiloxane containing vinyl group as base polymer, and oligomeric siloxane containing silicon hydrogen bond as vulcanization crosslinking agent. The formation reaction forms an elastomer with a network structure. The principle is that the polysiloxane containing vinyl group and polysiloxane with polyfunctional Si-H bond side group (or end group) is catalyzed by the eighth group transition metal compound (such as Pt, etc.) to carry out hydrosilation addition. A kind of silicone rubber that forms new Si-C bonds by forming reaction, chain growth and chain crosslinking.

Addition type liquid silicone rubber is usually composed of base polymer, cross-linking agent, inhibitor, catalyst, filler and other additives. Since in theory, no low molecular by-products are generated during the hydrosilation cross-linking process, and it has a high conversion rate. Therefore, the addition type liquid silicone rubber does not shrink during the vulcanization process, is non-toxic, has high mechanical strength, has excellent hydrolysis resistance (even in high pressure steam), good low compression set, low flammability, deep curing, easy To control the crosslinking density, the vulcanization rate can be controlled by temperature, and it does not corrode the materials in contact.

The physical, mechanical and electrical properties of addition type liquid silicone rubber after vulcanization can reach or exceed the level of compound rubber, and because it can be injection molded and molded, it has the advantages of convenient processing, high production efficiency, low cost, and energy saving. Some traditional mixing silicone rubber products have been replaced by liquid silicone rubber, which is a type of silicone rubber that is vigorously developed at home and abroad.

Fumed silica products can be used as fillers in addition-type liquid silicone rubbers. The application of fumed silica as fillers in silicone rubbers is the most commonly used, most effective, and most important. This is due to the fact that reinforced silicone rubbers The following types of crosslinks exist:

Covalent cross-linking between polymers;
Crosslinking between fillers and polymers;
Hydrogen bond cross-linking and cross-linking of van der Waals forces between fillers and polymer molecules;
The entanglement and cross-linking of fillers and polymer molecular chains;
Crosslinking caused by wetting of fillers by polymer molecules;
Crosslinking between fillers.