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The term silicone covers a large group of materials in which vinyl-methyl-silicone (VMQ) is often the central ingredient. Silicones are excellent seal materials for extreme temperature in static applications.  Outstanding flex and fatigue life, very good for ozone and UV radiation, insulating properties and physiologically neutral.  Silicones can be synthesized with a wide variety of properties and compositions and can be compounded to meet FDA, USP Class VI, USDA, 3-A and Canada AG standards.  They also have good resistance to fungal and biological damage.  This is silicone, not silicon, which is a chemical element.

Silicone has chemical resistance to engine and transmission oil, animal and vegetable oil and grease, brake fluid, fire-resistant hydraulic fluid, diluted salt solutions, along with moderate water resistance.

Some limitations of silicone are that they are not recommended for dynamic application since it has low strength and poor abrasion resistance and high gas permeability. They are not recommended for concentrated solvents, oils, concentrated acids, diluted sodium hydroxide, hydrocarbon based fuels or aromatic mineral oil.  Also not recommended for aromatic hydrocarbons (benzene, toluene), alkalis and superheated water or steam over 250-degrees.

The service temperature of silicone o-rings is generally minus 75-degrees to 400-degrees, depending on the compound and application. Silicone o-rings usually come in a reddish orange color.

Wishing you a safe and Happy New Year from Rocket Seals.

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