What is the difference between silicone sponge rubber and silicone foam rubber?
Simply put, silicone sponge and silicone foam use different raw materials and different manufacturing processes resulting in slightly different properties
and appearances. Silicone sponge is compounded with a gum type silicone, mixed and processed through a calender, a machine consisting of a series of
hard pressure rollers. Then it is run through a rotocure machine, which continuously vulcanizes the rubber. The characteristic fine fabric
finish on the surface of the silicone sponge is from conveyer belt used in the production process. Silicone sponge is a closed cell structure.
V22-100 is an example of a silicone sponge.
Silicone foam, on the other hand is made from a liquid silicone rubber. These relatively low viscosity liquids can be pumped to the vulcanizing
equipment. The liquid is cast onto a smooth liner (giving silicone foam its smooth surface appearance) and processed through curing ovens.
Silicone foams may be closed cell, open cell or a combination of open and closed cells. V23-000 is an example of a silicone foam.
What is the difference between silicone sponge per MIL-R-6130, Type 2, Grade A, B and C?
MIL-R-6130 is a military specification for chemically blown, cellular rubber. Type 2 is closed cell. Grade A is oil
and flame resistant, Grade B is non oil resistant and Grade C is Low temperature, non oil resistant. V22-300 is an example of Grade A and
V22-100 is an example of Grade B and C.
