What is a Liquid Silicone Rubber?

A Liquid silicone rubber is a high-purity, two-component platinum-cured silicone, ideally formulated for the production of technical parts, where strength, resistance and high quality are a must. LSRs are viscous, but pumpable materials, mostly processed through liquid injection molding (LIM)

Chemical structure

Liquid Silicone Rubber (LSR) is a two-component system, where long polysiloxane chains are reinforced with specially treated silica. Component A contains a platinum catalyst and Component B contains methylhydrogensiloxane as a cross-linker and an alcohol inhibitor. The primary differentiator between liquid silicone rubber (LSR) and high consistency rubber (HCR) is the “flowable” or “liquid” nature of LSR materials. While HCR can use either a peroxide or a platinum curing process, LSR uses only additive curing with platinum. Due to the thermosetting nature of the material, liquid silicone rubber injection molding requires special treatment, such as intensive distributive mixing, while maintaining the material at a low temperature before it is pushed into the heated cavity and vulcanized.

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Liquid silicone rubber properties

Depending on the application or its industrial use, LSR offers several advantages. First, it is highly biocompatible, which means it can be used for parts that come into contact with humans, for such applications as organ parts or prostheses. Second, it is very durable and therefore ensures long-term stability and chemical resistance. Third, it is also compatible with a wide spectrum of temperatures, from -60°C to +250°C, maintaining its high-performance mechanical properties at all times. Fourth, its electrical properties makes it ideal for insulation and precise conductivity protection. Finally, it is transparent and can be pigmented to harmonize with all color needs, including human skin tones.

LSR are also considered as the material of choice for industries such as Automotive or Medical devices for which small and complex elastomeric parts needs to be produced at high speed and optimum productivity. In such cases, Liquid Injection Molding of LSRs becomes one of the most efficient process to fabricators.