kSil® GP400
kSil® GP400 is a closed cell, lightweight silicone sponge with a density of 400 kg/m³ and a compression force deflection of 76 kPa — the firmest grade in the kSil® GP cellular sponge range. It is rated for service from -60°C to +230°C and carries the lowest compression set in the GP cellular range at 4%. Water absorption is less than 5%, and the material is available in thicknesses from 1.5 mm to 35 mm.
Key Properties
- Compression Force Deflection: 76 kPa (ASTM D1056)
- Tensile Strength: 750 kPa (ASTM D412)
- Elongation: 120% (ASTM D412)
- Compression Set: 4% (ASTM D1056)
- Density: 400 kg/m³ (ASTM D1056)
Operating Temperature Range: -60°C to +230°C
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- Specifications
- Applications
- General Info
- FAQs
Physical Properties
| Property | Value | Test Method |
| Density | 400 kg/m³ | ASTM D1056 |
| Minimum Thickness | 1.50 mm | — |
| Maximum Thickness | 35.00 mm | — |
| Colors Available | White, Black, Riox | Visual |
Mechanical Properties
| Property | Value | Test Method |
| Compression Force Deflection | 76 kPa | ASTM D1056 |
| Compression Set | 4% | ASTM D1056 |
| Tensile Strength | 750 kPa | ASTM D412 |
| Elongation | 120% | ASTM D412 |
| Water Absorption | <5% | ASTM D1056 |
Thermal Properties
| Property | Value | Test Method |
| Min Operating Temperature | -60°C | — |
| Max Operating Temperature | 230°C | — |
- Die-cut gaskets demanding the firmest compression response and lowest compression set in the GP cellular range
- Flexible sealing solutions in extreme-temperature environments requiring maximum dimensional stability
- Aerospace sealing applications where a high-density closed cell silicone sponge is required
- Automotive sealing components subject to sustained compressive loads in high-temperature environments
- Water contact sealing where low water absorption and structural firmness are required
Common industries: Aerospace, Automotive, Industrial Manufacturing, Water Infrastructure.
kSil® GP400 is the highest-density grade in the kSil® GP general purpose closed cell silicone sponge range. At 400 kg/m³ and 76 kPa compression force deflection, it provides the firmest compression response in the range and is designed for applications requiring maximum resistance to compressive deformation alongside reliable sealing performance across extreme temperature ranges.
With a compression set of 4% — the lowest in the GP cellular series per ASTM D1056 — and a tensile strength of 750 kPa, GP400 delivers both mechanical durability and outstanding elastic recovery under sustained load. Elongation is 120% and water absorption is less than 5%, consistent with its closed cell structure. The material operates from -60°C to +230°C and is available in White, Black, and Riox colorways.
What differentiates GP400 from GP350 and lower-density grades in the kSil® GP cellular sponge range?
GP400 is the firmest and densest grade in the GP cellular range, with a density of 400 kg/m³ and a compression force deflection of 76 kPa — significantly higher than GP350 (300 kg/m³, 48 kPa). It also carries the lowest compression set in the range at 4%, making it the optimal choice where maximum resistance to both compression and permanent deformation is required.
Why is compression set critical for cellular silicone sponge materials?
Compression set measures the degree of permanent deformation a material retains after sustained compressive loading. In gasket and sealing applications, a material with a high compression set will lose contact pressure against mating surfaces over time, allowing leakage or environmental ingress. GP400's compression set of 4% per ASTM D1056 is the lowest in the GP cellular range, indicating exceptional long-term seal retention.
What is the operating temperature range for GP400?
GP400 is rated from -60°C to +230°C.
Is GP400 suitable for regulated environments?
No compliance standards are specified on the manufacturer's TDS for GP400. Suitability for regulated environments must be confirmed through application-specific testing.
How should GP400 be specified?
Specify grade (GP400), thickness, color (White, Black, or Riox), compliance requirements, dimensional tolerances, and finished format.
