What is Liquid Silicone Rubber?

Silicone rubber is an elastic material based on linear polyorganosiloxanes, with added crosslinking agents, reinforcing fillers, and other additives, which form a network structure after vulcanization. It has excellent properties such as high and low temperature resistance, weather resistance, ozone resistance, arc resistance, electrical insulation, high breathability, and physiological inertness, and is widely used in many fields such as construction, automotive, electronics, power, medical, aviation, etc. Silicone rubber is divided into two categories: compounded silicone rubber and liquid silicone rubber according to its commercial form.

Compounded silicone rubber and liquid silicone rubber

Compounded silicone rubber is made by mixing high polymer linear polyorganosiloxanes with reinforcing fillers, additives, and vulcanizing agents, and then forming and vulcanizing them into finished products. Because it undergoes similar processes as general organic rubber, such as mixing, vulcanization, and compression molding, it is called compounded silicone rubber. Liquid silicone rubber is an elastic material made from medium molecular weight linear polyorganosiloxanes and does not require complex mixing and shaping equipment. It can be vulcanized into an elastic material by contacting with moisture or mixing with crosslinking agents at room temperature or slightly heated. According to its crosslinking and vulcanization mechanism, liquid silicone rubber can be divided into two types: condensation type and addition type systems.

Compared with compounded silicone rubber, addition type liquid silicone rubber has the following advantages:

• Addition type liquid silicone rubber is an injectable elastic material, and its processing technology is easily realized by mechanization, continuity, and automation. 

• It can greatly reduce labor intensity, improve the working environment, and increase molding efficiency by several times.

• Decrease in investment of processing equipment and molds.

• Save auxiliary costs (energy-saving, resource-saving).

• No need for solvents, water, and other dispersing media;processes are carried out in the liquid state (no solvents, no pollution); there are no small molecules and by-products produced during vulcanization, it is safe, non-toxic, and dimensionally stable.

• Properties and vulcanization speed can be adjusted over a wide range by extending the main chain and crosslinking methods.

Applications of addition type liquid silicone rubber

Addition type liquid silicone rubber has excellent transparency, tear strength, rebound resilience, yellowing resistance, thermal stability, water resistance, breathability, heat aging resistance, and weather resistance. At the same time, it has moderate viscosity and good fluidity, making it easy to operate, and the transparency of the finished product is high.

The numerous advantages of addition type liquid silicone rubber and its ease of processing have greatly expanded its application range, and it is now widely used in various industries such as electronics, daily necessities, automobiles, machinery, and medicine.