Expanded rubber has become a very popular product in the gasket industry. We are often asked for requests that use silicone sponge, which is closed cell only. Silicone foam is available in different cell structures, such as modified closed, closed, open, etc. There are many advantages to utilizing silicone sponge in various applications, including gasketing, cushioning, vibration dampening, enclosure sealing, and water sealing. NEDC mainly manufactures silicone sponge gaskets.
What is Silicone Sponge?
Silicone sponge is basically expanded silicone rubber. It is able to offer many of the same properties of silicone rubber. Some of these properties include ozone and UV resistance, temperature resistance, and low compression set. The compressibility of these materials is impressive; it easily allows closure to happen without extremely high pressure.
Another well-known property of silicone sponge is its feasibility of meeting UL 94 requirements such as V0 and below. The closed cell structure of the sponge is important under the pressure of water. These closed-off cells prevent the water from intruding into the aggregate structure of the sponge and keep the integrity of the seal against water. There is some contention on what exactly closed-cell sponge/foam is, but usually less or equal to 5% absorption is a good rule of thumb. These closed cells play a large part in the density of the material.
Applications for Silicone Sponge Gasketing/Cushions
Extreme Temperatures- Whether its outside up in Alaska, or its in the high heat, silicone sponge can deal with a wide operating temperature, typically -100°F to 500°F. I’ve seen them used in cryogenic applications, and for furnance applications as well.
Compression Set Resistance- Silicone Sponge highest compression set is normally 15%, however it can be even lower depending on which gasketing material chosen. For example R10480S Silicone Sponge is a low-compression set material with a typical compression set of 5%.
Outdoor Gasketing- Silicone Sponge is a good use for anything outdoor gasketing. Due to all of the benefits mentioned above- it nearly always makes a good outdoor gasket.
FDA Requirements- Many customers require the FDA 21 CFR 177.2600 for their products. These require ingredients that are compliant to the specification to be included in the material when its manufactured. These can include fillers, peroxides, and other additives.
It is well known that silicone sponge comes in a variety of densities, which range from Extra Soft to Extra Firm. The density and firmness play an integral role in how well the gasket compresses, and how well the gasket absorbs shock. Silicone sponge has a lot of different specifications that may be applicable in a given situation, such as AMS 3195(medium), AMS 3196(firm), ASTM D6576, MILR6130, ASTM D1056 2D3/2DA. and others.
UL Ratings of Silicone Sponge Products
Finding commercially available sealing/cushion products that are UL rated can be a challenge. One thing with silicone sponge/foam products is that there is a wide availability including:
UL-50E gasketing/sealing for electrical enclosures
UL94 HBF gasketing for flame retardant applications (R10460 Silicone Sponge UL94 HBF),
UL94 V0 gasketing for flame retardant applications (R10400 Silicone Sponge)
UL1570, UL1571, UL 1572(R10460 Silicone Sponge)
Other Availability of Silicone Sponge
The availability of silicone sponge material is virtually ubiquitous, with it being present industry wide. Most silicone sponges are provided with a textured fabric finish but may vary depending on part geometry and other variables. Although the natural rusty red is the typical color for silicone sponge, other colors are available upon request, such as grey, black, brown, blue, and white. There are many thicknesses of silicone sponge available, ranging from .032″ to 2.0″ thick.
Standard Silicone Sponge Products
|Saint Gobain Performance Plastics||Norseal R10460(Medium)||R10460 Datasheet Download (legacy CHR R10460)||Flame Retardant|
|Saint Gobain Performance Plastics||Norseal R10470(Firm or Medium)||R10470 Datasheet Download (legacy CHR R10470) / R10470F Datasheet Download (legacy CHR R10470)||General Purpose|
|Saint Gobain Performance Plastics||Norseal R10480(Soft or Medium)||R10480S Datasheet Download (legacy CHR R10480) / R10480M Datasheet Download (legacy CHR R10480)||Low Compression Set|
|Saint Gobain Performance Plastics||Norseal R10450||R10450 Datasheet Download (legacy CHR R10450)||Fiberglass Reinforced Silicone Sponge|
|Saint Gobain Performance Plastics||Norseal R10400(Medium)||R10400 Datasheet Download (legacy CHR R10400)||Flame Retardant|
|Rogers Corporation||BISCO® RS-800(Medium), RS-820(Firm), RS-840 (Very Firm) RS-870 (Soft)||RS-800 (Medium) Datasheet – RS-820 (Firm) Datasheet – RS-840 (Very Firm) Datasheet – RS-870 (Soft) Datasheet||Alternative to Silicone Foam Products|
More Information/Cutting of Silicone Sponge
NEDC regularly converts silicone sponge products into custom gaskets, and cushions through die cutting, and waterjet cutting. Silicone tape or Acrylic tape is available with these materials. Finally, silicone sponge extrusions can be supplied by NEDC at cut-to lengths, or in plain cord stock. Lastly, fluorinated silicone sponge is available as well. For more information concerning silicone sponge products or gaskets/seals made of silicone sponge please contact firstname.lastname@example.org.