Compounds are solid silicone rubbers. Usually a one-component glue, cross-linking agent, catalyst, inhibitor and rubber compound are mixed together. Compounded rubber is generally formed by high-temperature vulcanization after extrusion, unlike liquid rubber, which is mostly two-component and has three types: room temperature vulcanization, low temperature vulcanization, and high temperature vulcanization.

1. Production process:
After kneading with silicone rubber raw rubber, white carbon black and other fillers in a kneader, add cross-linking agents, catalysts, inhibitors, various colorants, etc. on a two-roll rubber mixer. The resulting rubber compound is referred to as a silicone rubber compound.

2. Physical properties/performance:
1. Before vulcanization (curing), it is "solid". The color depends on the color material added during mixing. If it is not added, it is white. The plastic value is about 200~300;

2. After vulcanization, the transparency without colorant is not as good as that of liquid glue, and the "light transmittance" is not higher than 70%. The "rebound value" of the compound with the same "hardness" is generally lower than that of liquid glue, but the "mechanical properties" "But it is generally higher than that of liquid glue, the "tensile strength" can reach 10~20MPa, the "tear strength" can reach 40~60KN/m, and the "elongation" is generally better than that of liquid glue with the same hardness. The "vulcanization temperature" is generally between 140 and 180 degrees.

3. Chemical properties/performance:
The raw rubber compound is a mixture of siloxanes. Its molecules belong to a chain-like spiral structure. The average molecular weight is about 400,000 to 800,000 mPa.s. Its viscosity is directly related to the molecular weight. Its molecular weight can be measured by Ubbelohde viscometer, which is probably the so-called viscosity-average molecular weight. Regarding the reinforcing mechanism of fillers, as far as I know, people on earth have not fully understood it yet. Probably the filler nanoscale SiO2 powder (precipitated SiO2 powder) is evenly distributed in the raw rubber to form a crystal-like structure. The hydroxyl groups on the surface of the SiO2 particles form hydrogen bonds with the Si-O bonds of the raw rubber. Each SiO2 particle acts as a A core extends out hydrogen bonds in all directions to connect with the molecular chain of raw rubber. Countless such structures, together with other additives, form a high-viscosity and high-performance rubber compound.

The performance (quality) is similar to that of general silicone rubber. As "silicone rubber" Baidu Encyclopedia said, silicone rubber has excellent heat resistance, cold resistance, dielectric properties, ozone resistance and atmospheric aging resistance. ℃ (or lower temperature) to +250 ℃ (or higher temperature) for long-term use. As for which property (quality) is better, it is determined by the type of raw rubber, fillers and additives used.