Production and properties of silicone rubber
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Solid silicone rubber is usually a single component adhesive, crosslinking agent, catalyst, inhibitor and compound mixed together. Mixed rubber is generally extruded after high temperature vulcanization molding, unlike liquid glue is mostly two components and there are room temperature vulcanization, low temperature vulcanization, high temperature vulcanization three categories.
Production process:
After kneading with silicone rubber raw rubber and white carbon black and other fillers in the kneading machine, add crosslinking agent, catalyst, inhibitor, various colors and other mixing on the two-roll rubber mixer. The resulting compound is called silicone rubber compound.
Physical Properties/Performance:
1, curing (curing) before, for the "solid", color according to the mixing of the color material, do not add is white, plastic value of about 200~300;
2, vulcanization, without color material transparency is not good liquid glue, "light transmittibility" is not higher than 70%, the same "hardness" of the compound "rebound value" is generally lower than liquid glue, but "mechanical properties" is generally higher than liquid glue, "tensile strength" up to 10~20MPa, "tear strength" up to 40~60KN/m, "Elongation" is generally better than the same hardness liquid glue. Vulcanization temperature is generally between 140 and 180 degrees.
Chemical Properties/Properties
Rubber is a mixture of siloxane, its molecules belong to the chain helix structure, the average molecular weight is about 400 ~ 800 thousand mPa.s, its viscosity and molecular weight has a direct relationship. Its molecular weight can be measured by a viscosimeter, which is probably the so-called viscosimetric molecular weight. Filler nano-sized SiO2 powder (precipitation method SiO2 powder) is evenly distributed in raw rubber, forming a crystal like structure, the hydroxyl group on the surface of SiO2 particles and the Si-O bond of raw rubber form hydrogen bonds, each SiO2 particle as a core, extending hydrogen bonds in all directions and raw rubber molecular chain connection, countless such structures, and add other additives, It is composed of high viscosity and high performance compound.
Silicone rubber has excellent heat resistance, cold resistance, dielectric property, ozone resistance and atmospheric aging resistance and other properties, silicone rubber outstanding performance is the use of a wide temperature, can be used in -60β (or lower temperature) to +250β (or higher temperature) for a long time. As for which sex (quality) can be better, is determined by the type of raw rubber and filler and additives used.