According to the differences in vulcanization methods and conditions, silicone rubber is generally divided into two types: high-temperature vulcanized rubber and room-temperature vulcanized rubber.
According to the product form and blending method, high-temperature vulcanized siliconerubber is further classified into high consistencyrubber (HCR) and liquid siliconerubber (R). High-temperature vulcanized silicone raw rubber is a high-molecular-weight polyorganosiloxane (with a molecular weight generally ranging from 400,000 to 800,000). The molecular weight of room-temperature vulcanized silicone raw rubber is usually lower (ranging from 30,000 to 60,000), with one or two functional groups at each end of the molecular chain (sometimes in the middle). Under certain conditions (moisture in the air, appropriate crosslinking agents and catalysts), These functional groups can react, thereby forming a three-dimensional cross-linked structure.
The rubber of room-temperature vulcanized silicone rubber can be classified into condensation type and addition type according to its vulcanization mechanism. According to their packaging methods, they can be further classified into two-component and one-component types. The typical properties of high-temperature vulcanized silicone rubber and room-temperature vulcanized silicone rubber are respectively shown in Tables 6.1 and 6.2. High-viscosity high-temperature vulcanized silicone rubber accounts for approximately 80% of the global silicone rubber market share, while liquid silicone rubber and room-temperature vulcanized silicone rubber each account for about 10%. Silicone rubber cured by light exposure is a relatively new type of silicone rubber product, and its market share is still relatively small at present.