Silicone rubber is the largest type of silicone products, and is an elemental organic elastomer obtained by hydrolysis and polycondensation of various dichlorosilanes. Divided into thermal vulcanization type (high temperature vulcanization silica gel HTV), room temperature vulcanization type (RTV), of which the room temperature vulcanization type is divided into polycondensation reaction type and addition reaction type. High temperature silicone rubber is mainly used to manufacture various silicone rubber products, while room temperature silicone rubber is mainly used as adhesive, potting material or mold. The thermal vulcanization type has the largest amount, and the thermal vulcanization type is divided into methyl silicone rubber (MQ), methyl vinyl silicone rubber (VMQ, the largest amount and product brand), and methyl vinyl phenyl silicone rubber PVMQ (low temperature resistance, radiation resistance). ), and other fluorosilicone rubber.

1. Characteristics of silicone rubber

The molecular structure of silicone (polydimethylsiloxane) is dominated by siloxane bonds, and the structure is very stable. Therefore, compared with ordinary organic rubber, silicone compounds have many beneficial properties, such as heat resistance, electrical Insulation, chemical stability, etc.

Since silicone has a helical structure and the intermolecular force is very small, silicone has good elasticity, stretchability, cold resistance, etc. In addition, since the methyl group on the outside of the helical structure can rotate freely, silicone can exert many unique surface properties, such as water repellency, mold release and so on.

2. Processing of silicone rubber

The mixed rubber is made by adding silicone rubber raw rubber to a double-roll rubber mixing machine or a closed kneader and gradually adding silica, silicone oil, etc. and other additives for repeated refining. According to the different fillers and additives added, the performance of silica gel is also different.

3. The production process of silicone rubber

The molding of the mixed rubber needs to apply a certain temperature and pressure under the action of the vulcanizing agent (only necessary for the solid state, the purpose is to prevent the generation of air bubbles), and the product is made by molding or extrusion process. For example, HTV needs to be around 165°C, and LSR (liquid silicone rubber) needs to be around 140°C.

4. Application of silicone rubber

Silicone rubber has a wide range of applications, and can produce many model products and industrial supporting products. Because silicone rubber is non-toxic, it is widely used in medical and health care and food industries. In addition, silicone rubber can also be used as coating and sealing of various electronic tubes or electrical components, and has products such as moisture-proof, dust-proof and shock-proof.