Product Description
Closed-cell sponge rubber can be formulated from several different elastomeric materials in a variety of densities. The most common materials are Neoprene/EPDM/SBR blend, Neoprene, EPDM, and Silicone. Sponge rubber can be specified in low, medium, or high-density hardness. When used with pressure-sensitive adhesives or Heat Activated Tape Systems (HATS), it becomes a highly flexible material that can conform to almost any surface application. Sponge rubber is a gas-impermeable cell material and offers:
- Controlled compression and recovery properties
- Shock-absorbing properties
- High-performance sealing capabilities
Closed-cell sponge rubber or expanded rubber is made up of individual cells, similar to balloons, that trap gas inside and prevent moisture from passing through the cell walls unless they rupture. The cells in closed-cell sponge rubbers are not interconnected, meaning they do not allow air or water to pass through the sponge at low pressures.
The cell walls of sponge rubber can be damaged in the following ways:
- Repeated flexing can cause gas to pass through the cell walls
- When compressed up to 50-70%, closed sponge cells can burst
Compounding
The raw compounds of sponge rubber parts are mixed on the same type of equipment as solid rubber compounds, with the addition of a chemical blowing agent. As a chemical additive, the blowing agent reacts with the rubber compound during the heat and pressure of the pre-cure and pre-shaping process, generating nitrogen gas. As this reaction occurs, the mixed sponge rubber batch is placed in an oven, where it expands into a bun. Afterward, the bun is cured and cut into individual sheets.
Sponge rubber parts can be formulated from various materials.
- Closed-Cell Silicone Sponge Rubber
- Closed-Cell EPDM Sponge Rubber
- Closed-Cell Neoprene Sponge Rubber
- Blended Closed-Cell Sponge Rubber