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Home > Materials > Silicone Sponge Rubber, Closed Cell Silicone Sponge

Silicone Sponge Rubber Products, Gaskets, Cushions

Silicone Gaskets

Silicone sponge products are a core product group at Stockwell Elastomerics. Stockwell Elastomerics inventories and fabricates the full product line of Saint-Gobain's COHRlastic® closed cell silicone sponge materials that include sponge sheets with low compression set properties, UL 94HB, UL 94V-0 flame ratings, thermal conductivity, fluid and fuel resistant fluorosilicone and general purpose silicone sponges. Stockwell Elastomerics applies a variety of pressure sensitive, acrylic and silicone pressure sensitive adhesive backings and can furnish parts with a conductive surface coating for high temperature ESD grounding applications. Additionally, Stockwell Elastomerics regularly applies a conductive surface coating to silicone sponge where soft sponge is needed in combination with ESD protection.

Silicone sponge and silicone rubber sheet are readily fabricated into silicone sponge gaskets and cushioning pads. Fabricating processes include: die cutting, water jet cutting, adhesive lamination and strip slitting. Stockwell Elastomerics offers cut-to-size (waterjet) prototypes to help engineers and designers with "proof of concept".

Closed cell silicone sponge gaskets and cushioning pads Silicone Materials Selection Guide

What is Silicone Sponge?

Most commercially available silicone sponge products are made from gum based polydimethylsiloxane (PMDS). The polymer is chemically expanded when heat cured to create the closed cell sponge structure. The expanding process might be compared to adding yeast to bread to make it rise, creating compressible air pockets. Expanded closed cell silicone sponge offers many of performance benefits of solid silicone in a softer and more compliant form.

Visit the Silicone Sponge and Silicone Foam Sheet Material Data Sheets page for detailed technical information on these materials.

Key Benefits of Closed Cell Silicone Sponge

  • Wide operating temperature - silicone sponge has a temperature range of -100°F to 500°F (-73°C to 260°C).
  • Water sealing - the closed cell structure allows for good water sealing with relatively low compressive forces.
  • Compression set resistance - silicone offers excellent compression set resistance (ability to rebound to original thickness), especially at higher temperatures, compared to most rubber material. Low compression set silicone sponges are available for even better performance than general purpose grades.
  • UV and ozone resistance - silicone products have excellent UV and ozone resistance due in part to their inorganic backbone. This provides long term performance.
  • Rugged - when silicone is required, silicone sponge parts offer better toughness as compared to silicone foam products.
  • Outdoor gasketing - considering all the above benefits, silicone sponge is a good material choice for outdoor environments, from the Arctic to the desert.

Silicone Sponge Products

Stockwell offers the following expanded silicone sponge products in sheet/roll form, die cut or water jet cut parts. All products listed below are available with acrylic or silicone adhesive backing of choice. (View Stockwell Elastomerics' adhesive options.)

  • General purpose: R-10470-M medium, R-10470-F firm, S-10418-XF extra firm
  • Low compression set: R-10480-S soft, R-10480-M medium
  • UL 94 flame rated: R-10460-M, UL 94HB, R-10400 UL 94V-0 (UL-listed)
  • Fuel and chemical resistant: R-10490 fluorosilicone
  • Thermally conductive: R-10404
  • Reinforced: R-10450 fiberglass reinforced for dimensional stability
  • Electrically Conductive: S480-62-CON soft, S470-62-CON medium, S418-62-CON extra firm, sponge with carbon filled silicone coating for ESD grounding applications

Silicone Sponge Tape

Kiss-cut silicone sponge gasket Kiss-cut silicone sponge

Silicone sponge tape also called strip gasket or Strip-N-Stick®. These silicone gasket tapes are supplied with a premium, peel-and-stick, acrylic adhesive backing. A silicone adhesive backing is also available for extreme temperature applications. Silicone gasket tapes are most commonly used for enclosure gaskets. View more information on silicone sponge gasket tapes offered by Stockwell Elastomerics.

Silicone Sponge Burn Test Video

UL 94V-0 rated silicone sponge being exposed to a flame from a torch. This is not an official UL test. Silicone sponge is used for enclosure gaskets, cushioning pads. Silicone foam and silicone sponge have a wide temperature range but without special chemistry they will burn. R-10400 silicone sponge is formulated to meet an aggressive UL 94V-0 flame rating.

Silicone Sponge or Silicone Foam? What is the Difference?

Silicone sponge, also called closed cell silicone sponge or expanded silicone, is derived from a thin sheet of uncured silicone gum that expands to a controlled thickness while curing in a high temperature press or rotocure operation. Closed cell means that the cells are non-interconnecting, therefore they do not allow water to wick through the sponge. Generally, silicone sponges have superior mechanical properties and are considered to have a complete closed cell structure. Silicone sponge often provides better water sealing in wash-down applications as compared to silicone foam.

Silicone foam is normally considered to be an open cell, lightweight product that is derived from liquid silicone ingredients that are cast onto a liner and cured in an oven. Higher density silicone foams have been developed, in recent years, that are suitable for water sealing. Low density open cell silicone foams may allow moisture to pass through the cell structure unless the design allows for extensive deflection of the gasket. In contrast, higher density silicone foam products will have a higher proportion of closed cells compared with medium or low density grades. With the proper amount of deflection, it is possible to achieve a good long term weather seal and rain seal with silicone foam.

Specifications Met by Silicone Sponge Materials

Many silicone sponge materials meet AMS3195, AMS3196, MIL-R-46089, MIL-R-6130 Type II and ASTM D6576 specifications. UL 94V-0 flame rated silicone sponge is available. Also see Silicone Foam materials for other UL 94, UL 50, UL 50E, UL 508 (UL 60947), UL 1570, UL 1571, UL 1572, UL 157 requirements.

Silicon Sponge or Silicone Sponge?

Although silicon sponge or silicon is called out frequently called out on drawings, silicone sponge is the widely accepted terminology used in the rubber industry. Expanded silicone is also used.

Contact Stockwell Elastomerics for Silicone Sponge

Contact Us for further assistance with custom fabricated silicone sponge gaskets, expanded silicone, closed cell silicone sponge and sheet silicone sponge gaskets and pads

COHRlastic® is a registered trademark of Saint-Gobain.

Related Information:

Extra Thin Silicone Sponge Materials

    Silicone Sponge and Silicone Foam Sheet Material Data Sheets page

Listing of Pressure Sensitive Adhesives

Compression Force Deflection Curves for Closed Cell Sponge

Silicone Materials Selection Guide