The Low Tolerance Spec

The United Seal & Rubber Co. Blog

Silicone Rubber Gasket Material

Posted by Virgil Alonso on Thu, Aug 29, 2013 @ 10:08 AM

Silicone Rubber Gasket Material resized 600

Silicone rubber compounds offers numerous advantages not found in many other rubber polymers. Silicone rubbers have good electrical, chemical, flame retardancy, and excellent resistance to heat and cold. These unique qualities make it appealing for use in electronics, automation, automotive, medical devices and food products.

Silicone rubbers can withstand both high and low temperatures far better than most available options. Silicone rubber can be used at high temperature (100+ Celsius) with almost zero change in it properties. This makes silicone rubber gaskets suitable for high temperature environments. Silicone rubber has great resistance to cold environments with an embrittlement point around -70 Centigrade. Around the embrittlement point silicone can retain its elastic abilities.

Weathering conditions such as wind, rain and ultraviolet rays have virtually no effect on its physical properties. Rainfall percent absorption is practically none. You could submerge the material for several hours and can expect to see no effect on mechanical strength or its electrical properties. Note that if silicone was exposed to moisture under pressure the process of degradation greatly increases. This can be remedied with selecting a curing agent to improve its resistance to steam (hot pressurized water).

Silicone rubber has excellent resistance to oil at high temperatures. This quality is especially important when considering applications at temperature higher than 100 Centigrade. Other synthetic rubbers have outstanding oil resistant properties, but this tends to fall short after reaching the materials operating temperature limits.

Silicone also has excellent resistance to solvents and other chemicals. It is virtually unaffected by polar compounds, such as aniline and alcohol.  Non-polar organic compounds like benzene, toluene and gasoline cause silicone to swell.   However, unlike other organic polymers it will eventually return to its former state once the before mentioned compound is removed.

Silicone rubber has high insulation qualities that are stable over a wide range of temperatures and frequencies. Even immersed in water won’t hinder its insulation properties. It has particularly good resistance to corona discharge (ionization of fluid) and arcing at high voltages.

Thermal conductivity of silicone is higher than that of your typical organic polymer. Special inorganic fillers are mixed with silicone to improve thermal conductivity if so desired. It has been used in application involving thermal interface sheets and heating rollers.

Electrically conductive silicone rubbers contain carbon to improve its performance. It has been used in components including heaters, antistatic material and high-voltage cable shielding. It is even used in the very keyboard I am using right now to type this blog.

Silicone rubber has so many different types of possible applications it is hard to list them all. It has been used in medical and food applications because of its inherent nature to resist chemical attack, making it ideal for maintaining a clean environment. It is even possible to chemically alter the compounds composition in order to successfully utilize all the great properties silicone has to offer.

We offer silicone compounds that meet FDA, USP Class VI and UL requirements to name a few options.  Please contact us to allow us the opportunity offer solutions for your application.


Tags: Specification Tip