What Is Silicone Foam?

Foam silicone rubber is a kind of tape made by condensing hydroxy-terminated silicone rubber, using hydroxy hydrogen-containing silicone oil as a foaming agent, and a vinyl platinum complex as a catalyst, and foaming and curing at room temperature. Porous sponge-like elastomer. Foam silicone rubber formulated with room temperature vulcanized silicone rubber has a wider temperature range than other foam elastomers, and has high thermal stability, good insulation, heat insulation and moisture resistance, excellent shock resistance, especially vibration resistance at high frequencies. Better performance, it is an ideal lightweight packaging material, can be used for a variety of electronic components, instruments, meters, flying instrument wheels, insulation filling materials, floating materials in salt mist atmosphere, sealing materials, orthopedics Surgical stuffing, repair and gauze materials. ^[1]

Silicone rubber is composed of silicon-oxygen bonds (Si-O) alternately composed of its main chain, and organic groups (such as methyl, ethyl, vinyl, phenyl, trifluoropropyl, etc.) constitute a linear type of its side groups Polyorganosiloxane. Since the introduction of a small amount of vinyl into the large molecular structure of silicone rubber can greatly improve the vulcanization and processing properties of silicone rubber, most of the currently used silicone rubbers contain vinyl. Methyl vinyl silicone rubber is the most common type of silicone rubber and currently dominates silicone rubber products at home and abroad. Due to the special nature of the structure, silicone rubber has excellent properties that many other materials cannot simultaneously have, such as excellent high temperature and low temperature resistance, excellent oil resistance, solvent resistance, UV resistance, radiation resistance, and good aging resistance. Excellent electrical insulation and chemical stability and physiological inertia.

Silicone rubber foam material is a porous polymer elastic material prepared after silicone rubber is foamed. It is also called sponge silicon rubber and microporous silicon rubber. According to the cell structure, it can be divided into closed cell, open cell and mixed cell foam silicone rubber. Generally speaking, open-cell foams have lower mechanical strength, but have better compressive stress relaxation properties, while closed-cell foams have better mechanical strength, but have lower compressive stress relaxation properties. The properties of mixed-cell foams are somewhere in between.

According to the preparation method, silicone rubber foam materials can be divided into room temperature vulcanized silicone rubber foam (RTV) and high temperature vulcanized silicone rubber foam (HTV). Room temperature vulcanized silicone rubber foam usually uses condensation type hydroxy-terminated silicone rubber as the base material and hydroxy silicone oil as the foaming agent.

A platinum complex is a catalyst and is a foamed porous elastomer made by vulcanization and foaming at room temperature. Room temperature vulcanized silicone rubber foam is suitable for in-situ foam molding, and plays the role of filling, sealing, and shock absorption. The traditional preparation method of high temperature vulcanized foam silicone rubber is to silicone rubber, foaming agent and vulcanization containing particulate inorganic filler The agent is uniformly mixed to prepare a kneaded rubber, and then heated to vulcanize and foam to obtain a silicone rubber foam. The high-temperature vulcanized foam silicone rubber can be molded into a foam sheet and used after cutting. It can also be extruded and then subjected to continuous hot air vulcanization to produce various shapes of silicone rubber foam strips.

Foam silicone rubber is a kind of tape made by condensing hydroxy-terminated silicone rubber, using hydroxy hydrogen-containing silicone oil as a foaming agent, and a vinyl platinum complex as a catalyst, and foaming and curing at room temperature. Porous sponge-like elastomer. The hydrogen gas generated during the reaction foams the rubber compound during vulcanization. The amount of foaming agent hydroxy hydrogen-containing silicone oil will affect the reaction speed and the structure of the foam. Too much amount will cause more open cells on the surface of the foam, which will accelerate the vulcanization speed; when the amount is small, the volume expansion will be small and the product density will increase. ^[2]

Foam silicone rubber is an ideal lightweight packaging material due to its high thermal stability, good thermal insulation, insulation, moisture resistance, and shock resistance, especially at high frequencies. Various electronic components, instruments, meters, and flying body instrument wheels can play the role of "three-proof" protection against "moisture, shock, and corrosion." In addition, it can also be used as a filling material for thermal insulation interlayers, a floating material in a salt fog atmosphere, and a sealing material. Foam silicone rubber can also be used as orthopedic filling, repairing and gowning materials in medicine.

In order to meet the fire protection requirements of transmission lines, the American Dow Corning Company has developed a flame retardant room temperature vulcanized silicone rubber DC3-6548. This foamed silicone rubber is mainly used for fire-proof sealing where wires and cables pass (such as holes in roofs, walls, buildings, etc.), and its flame retardancy is very good. Its limiting oxygen index is 39 (most plastics have a limiting index of only 20). With a service life of up to 50 years. At present, this kind of flame retardant room temperature vulcanized foam silicone rubber has been widely used in nuclear power stations, electronic computer centers, offshore oil production equipment and other places with harsh environmental conditions or fire protection requirements.