Liquid silicone rubber is one of the raw materials for customized silicone products. It has excellent performance and can be used to produce custom silicone parts and silicone consumer products. The application range includes many industrial fields such as automobiles, medical care, electronics, and life. Among them, meteorological silica is closely related to liquid silicone rubber.
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 groups and polysiloxanes with polyfunctional Si-H bond side groups (or end groups) undergo hydrosilation under the catalysis of Group VIII transition metal compounds (such as Pt, etc.). A kind of silicone rubber that forms new Si-C bonds by forming reaction, chain growth, and chain crosslinking.
Properties of Addition Liquid Silicone Rubber
Addition type liquid silicone rubber is usually composed of basic 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, 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), has 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 molding and compression molding, 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 Some traditional mixing silicone rubber products have been replaced by liquid silicone rubber, which is a type of silicone rubber that is vigorously developed at home and abroad. The growing use of custom silicone parts is one example.
Cross-linking of silicone rubber
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 because 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;
- entanglement and cross-linking of fillers and polymer molecular chains;
- Crosslinking is caused by the wetting of fillers by polymer molecules;
- Crosslinking between fillers.
To meet the needs of the market, a variety of functional addition liquid silicone rubbers have been developed:
Self-lubricating addition-type liquid silicone rubber can reduce friction during the assembly process of the seal ring, reduce or avoid the damage of parts, and improve the self-lubricating performance of the oil seal;
Heat-resistant addition type liquid silicone rubber, superfine sericite/addition type liquid silicone rubber with excellent performance is prepared by solution polymerization method, and the initial decomposition temperature can be increased compared with pure silicone rubber;
Soft liquid injection molded silicone rubber with the right softness, feels like human skin, is dry to the touch, non-oily, suitable for shock absorption and soft-touch applications.
Silicone rubber materials affect product customization
The properties of silicone rubber will vary depending on the compound added. Different properties of silicone rubber can create value and benefits for different application needs. If you happen to have an idea for custom silicone products, please contact NEWTOP immediately.
NEWTOP is a professional custom silicone molding manufacturer. We have provided various silicone rubber products with different performances for customers around the world for many years. Our experienced engineer consultant team is very happy to provide you with comprehensive production advice and other Related technical support.