Sponge Silicone Sheet: Closed Cell, Medium Density
ElastaPro makes sponge silicone sheet with closed cells in medium density. This gasketing material is available in continuous rolls up to 1/2” thick and in sheets up to 2” thick. The surface has a fine fabric finish. ElastaPro can slit medium-density, closed cell silicone at various widths, and we can apply a pressure sensitive adhesive (PSA) to help you speed installation.
Closed Cell Silicone Sponge Data Sheet (ESS11M)
What is Sponge Silicone Sheet?
A sponge silicone sheet is a flexible, compressible, and resilient material with a closed-cell structure that is used for sealing, cushioning, and insulation. It is a type of synthetic rubber that can withstand a wide range of temperatures and resists environmental factors like UV and ozone exposure. This makes it ideal for use in demanding environments and applications requiring sealing, shock absorption, or vibration dampening.
Properties of Sponge Silicone Sheet
- Cellular structure: It is a closed-cell elastomeric material, meaning its structure contains many tiny, non-interconnecting air-filled cells. This structure makes it compressible and able to conform to irregular surfaces.
- Temperature resistance: Silicone sponge sheets can operate within a broad temperature range, typically from -60C to over 230C.
- Environmental resistance: It is highly resistant to UV, ozone, and general weathering, which allows for long-term performance in outdoor or harsh conditions.
- Compression set resistance: It maintains its original shape and thickness even after being compressed for extended periods, especially at higher temperatures.
What is Medium-Density Closed Cell Silicone Sponge?
Medium-density closed cell silicone sponge is a compressible, water resistant material that’s used in sealing and cushioning applications. Like solid silicone, this cellular material resists extreme temperatures, ultraviolet (UV) light, and ozone. However, medium-density closed cell silicone sponge is often lighter and more compliant.
As a medium-density material, closed cell silicone sponge offers a compromise between softness and firmness. It provides sealing and cushioning without excessive compression, and its low compression set means that it resists permanent deformation after being compressed. Medium-density corresponds to a specific compression deflection range and is not based on density alone.
The closed cells in medium-density closed cell silicone sponge prevent the passage of gases or water. These closed cells are filled with air, which has a low thermal conductivity. Consequently, closed cell silicone sponge is a thermal insulator. Compared to open cell silicone foams, it’s tougher and has better tear resistance.
Key Benefits of Closed Cell Silicone Sponge in Medium Density
Medium density closed cell silicone sponge resists extreme temperatures, has low water absorption, and offer excellent compression set resistance. The list below provides more information.
- Temperature Resistance: ElastaPro’s cellular material resists temperatures from -85°F to +450°F (Intermittent). This is a wider operating range than many non-silicone elastomers.
- Closed Cell Structure: The closed cells prevent the absorption of water and moisture, which supports the material’s use in sealing applications.
- Low Water Absorption: ElastaPro’s medium-density closed cell silicone sponge has a water absorption percentage of just 5% (Max).
- Compression Set Resistance: Even at high temperatures, this material maintains its shape and sealing properties after repeated compression.
- Environmental Resistance: Closed cell silicone in medium density resists sunlight, ozone, and weathering.
- Durability: This rugged and long-lasting material maintains its strength and dimensional stability.
- Smooth Surface Finish: ElastaPro’s medium-density closed cell silicone has a smooth surface for better sealing and the easier application of adhesives.
Specifications for Medium-Density Closed Cell Silicone Sponge Sheet
ElastaPro’s medium-density closed cell silicone materials meet the following specifications
- AMS 3195 for aerospace applications.
- MIL-R-46089 for military gaskets like aerodynamic and rain seals on aircraft and missiles.
- ASTM D1056 for automotive and industrial manufacturing applications.
- MIL-R-6130 for military seals, gaskets, and insulation
- MIL-STD-670 TE12 for gasketing where a soft, compressible material is needed to absorb shock and maintain a seal under harsh conditions.
Properties for Closed Cell Medium-Density Silicone Sponge Sheet
This table* compares AMS-3195 values to typical ESS11MM values and indicates the test method.
| Property | AMS-3195 | ESS11MM | 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 with closed cells 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 for closed cell silicone sheets in medium density 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 sheet 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.
Ask Elasto Proxy for Closed Cell Medium Density Silicone Sponge Sheet
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.
