Sponge Silicone Sheet: Closed Cell, Medium Density
ElastaPro makes sponge silicone sheet with closed cells in medium density.
Why use Sponge Silicone Sheet?
Sponge silicone is an excellent material for gasketing applications that require a soft, compressible material. It is resistant to extreme temperatures and offers good compression set. The surface has a fine fabric finish and is available in continuous rolls up to ½” thick and sheets up to 2” thick.
Key Characteristics of Sponge Silicone Sheet
- Extreme High & Low-Temperature Resistant -85ºF to +450ºF (Intermittent)
- High Compressibility
- Low Compression Set
- Excellent gasketing material
- UV / Ozone Resistant
- Specifications: AMS3195, Mil-R-46089, ASTM D1056, Mil-R-6130, Mil-Std 670 TE12, Formulated to meet UL94HB
| Properties | Specification AMS-3195 | ESS TYPICAL VALUES | Test Method |
| Density, lbs/cu.in. - Under 1⁄4” thick | .025 MAX | .020 | ASTM D1056 |
| Density, lbs/cu.in. - Over 1⁄4” thick | .020 MAX | .018 | ASTM D1056 |
| Compression Deflection,, psi | 6-14 | 11 | ASTM D575 |
| Compression Set, 22 hrs. @ 212°F | 60% MAX | 29 | ASTM D395 |
| Brittle Point, °F | -67 | -103 | ASTM D746 |
| Temperature Range, °F | N/A | -103 TO +450 | ASTM D573 |
| Water Absorption | 5% MAX | PASS | ASTM D471 |
| Tensile Strength, psi | N/A | 100 | ASTM D412 |
| Elongation, % | N/A | 200 | ASTM D412 |
| Thermal Conductivity, BTU in./hr ft 2F | N/A | .6 | ASTM F433 |
| Permittivity | N/A | 1.39 C2/(N·M2) | ASTM D150 |
| Dielectric Strength | N/A | 1.6 KV/mm | ASTM D149 |
| Volume Resistivity | N/A | 10^15 OHM-CM | ASTM D257 |
These typical physical properties are provided for evaluation information only. It is up to the end-user to determine the appropriate material for the intended application.
Applications for Closed Cell Medium Density Sponge Silicone Sheet
Closed cell medium density sponge silicone sheet is a versatile material valued across industries for its balance of compressibility, resilience, and durability. Unlike open-cell foams, closed-cell silicone has sealed pockets that resist water absorption, making it suitable for environments where sealing against moisture, air, dust, or chemicals is essential. With its medium density, the sheet provides a compromise between softness and firmness, enabling reliable sealing and cushioning without excessive compression set. These properties make it a go-to material for engineers and designers who need performance in demanding applications.
Sealing and Gasketing
One of the most common uses of medium density closed cell silicone sheet is in sealing and gasketing. Because the material resists water, UV, ozone, and temperature extremes, it is ideal for both indoor and outdoor applications. In automotive and aerospace settings, it is cut into gaskets that maintain their integrity under vibration and heat cycling. For enclosures that house electronics, the sheets are die-cut into seals that prevent ingress of dust, water, or electromagnetic interference. The closed-cell structure ensures that when compressed, the seal remains airtight and watertight, protecting sensitive equipment.
Thermal Insulation and Temperature Resistance
Silicone’s inherent resistance to high and low temperatures expands its application range. Medium density sponge silicone sheets can be used as thermal barriers in industrial ovens, HVAC systems, and engine compartments. Their closed-cell construction minimizes heat transfer while maintaining flexibility, making them suitable for gasketing in environments where thermal cycling would cause other materials to fail. The sheets also resist hardening or cracking at low temperatures, making them reliable in cold storage applications.
Vibration Dampening and Cushioning
Another important use is vibration isolation. Medium density sponge silicone absorbs shocks and dampens vibration, extending the life of mechanical assemblies and protecting delicate components. In transportation and heavy machinery, the material serves as a vibration pad or cushion. In electronics, it helps prevent micro-vibrations that could damage circuit boards or optical components. Because the sponge silicone compresses evenly and rebounds reliably, it provides long-term cushioning without losing thickness.
Weatherproofing and Outdoor Applications
Closed cell sponge silicone is widely used in outdoor equipment and architectural applications. For example, it is applied in window seals, skylight gaskets, and door insulation where exposure to sunlight, ozone, and varying weather conditions could degrade lesser materials. Its ability to withstand UV radiation without significant degradation makes it suitable for solar energy systems and outdoor lighting enclosures. Marine applications also benefit from the sheet’s resistance to saltwater, providing reliable seals on vessels and offshore equipment.
Medical and Food Processing Equipment
Because many silicone sponge materials can be formulated to meet FDA or medical-grade standards, medium density sheets are also applied in healthcare and food environments. They are cut into gaskets for sterilization chambers, seals for peristaltic pumps, and cushioning pads in diagnostic devices. Their closed-cell structure ensures hygienic performance since they do not absorb fluids and are easy to clean.
Conclusion
Closed cell medium density sponge silicone sheet offers a unique combination of sealing, insulating, and cushioning properties. Its durability in harsh environments, resistance to weathering and temperature extremes, and flexibility in design make it an indispensable material for industries ranging from aerospace to food processing. By balancing softness with firmness, it provides engineers with a reliable solution where both performance and longevity are critical.
