kSil® US400
kSil® US400 is a lightweight, closed cell silicone sponge with a density of 440 kg/m³ and a compression force deflection of 100 kPa, approved to Aerospace Material Specification AMS 3196. It is rated for service from -60°C to +230°C, passes FAR 25.853 Horizontal flame resistance at both 12 and 60 seconds, and features a very low compression set of 3%. Water absorption is less than 5%, and the material is available in thicknesses from 1.6 mm to 25.0 mm.
Key Properties
- Compression Force Deflection: 100 kPa (ASTM D1056)
- Tensile Strength: 1100 kPa (ASTM D412)
- Elongation: 320% (ASTM D412)
- Compression Set: 3% (ASTM D1056)
- Density: 440 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 | 440 kg/m³ | ASTM D1056 |
| Minimum Thickness | 1.60 mm | — |
| Maximum Thickness | 25.00 mm | — |
| Colors Available | Red-orange | Visual |
Mechanical Properties
| Property | Value | Test Method |
| Compression Force Deflection | 100 kPa | ASTM D1056 |
| Compression Set | 3% | ASTM D1056 |
| Tensile Strength | 1100 kPa | ASTM D412 |
| Elongation | 320% | ASTM D412 |
| Water Absorption | <5% | ASTM D1056 |
Thermal Properties
| Property | Value | Test Method |
| Min Operating Temperature | -60°C | — |
| Max Operating Temperature | 230°C | — |
Flame & Fire Performance
| Property | Value | Test Method |
| UL94 V-0 | Fail | UL94 (File #E83967) |
| Flame Resistance @ 12 Sec | Pass | FAR 25.853 |
| Flame Resistance @ 60 Sec | Pass | FAR 25.853 |
| Toxic Gas Emissions Rating | Fail | SMP-800C @ 1.5/4.0 min |
Compliance
- AMS 3196 — Compliant
- FAR 25.853 Horizontal — Compliant
- Aerospace gaskets and seals requiring AMS 3196 qualification and FAR 25.853 horizontal flame compliance
- Die-cut gaskets demanding firm compression resistance and very low long-term compression set
- Flexible sealing solutions across a wide service temperature range of -60°C to +230°C
- Automotive sealing components evaluated for FMVSS 302 compliance
- Industrial sealing applications requiring high elongation and excellent elastic recovery in a high-density closed cell sponge
Common industries: Aerospace, Automotive, Industrial Manufacturing.
kSil® US400 is a high-density closed cell silicone sponge in the kSil® US series, approved to AMS 3196 for aerospace applications. At 440 kg/m³ and 100 kPa compression force deflection, it delivers a firm sealing response and is designed for aerospace gaskets, die-cut seals, and flexible sealing solutions in demanding temperature and environmental conditions requiring both flame compliance and material qualification traceability.
The US400 achieves a tensile strength of 1100 kPa, an elongation of 320% — notably high for a sponge at this density — and a compression set of 3% per ASTM D1056, indicating excellent long-term elastic recovery. Water absorption is less than 5%. FAR 25.853 horizontal flame resistance is passed at both 12 and 60 seconds. UL94 V-0 and SMP-800C toxic gas emissions testing did not pass as recorded on the TDS.
The material is available in sheets and rolls with widths up to 36″, with a Pressure Sensitive Adhesive (PSA) option. Standard colour is red-orange.
Compliant with AMS 3196 and FAR 25.853 Horizontal. FMVSS 302 compliance is referenced in the typical applications section of the TDS.
What differentiates US400 from US350 in the kSil® US cellular sponge series?
US400 is approved to AMS 3196 versus US350's AMS 3195, reflecting distinct aerospace material qualification levels. US400 is firmer (100 kPa CFD vs. 48 kPa) and denser (440 kg/m³ vs. 300 kg/m³), and its compression set of 3% is lower than US350's 8%, indicating superior elastic recovery. US400 also exhibits a notably high elongation of 320% for a sponge at this density level.
Why is compression set critical for cellular silicone sponge materials?
Compression set measures how much permanent deformation a material retains after sustained compressive loading. For aerospace and industrial sealing applications, a low compression set ensures the gasket maintains contact pressure against mating surfaces over the service life of the assembly. US400 exhibits a compression set of 3% per ASTM D1056 — among the lowest in the kSil® cellular sponge range.
What is the operating temperature range for US400?
US400 is rated from -60°C to +230°C.
Is US400 suitable for aerospace or flame-rated environments?
Yes. US400 is approved to AMS 3196 and passes FAR 25.853 Horizontal flame resistance at both 12 and 60 seconds. UL94 V-0 and SMP-800C toxic gas emissions tests are recorded as Fail on the TDS. Applications requiring those specific ratings should evaluate alternative grades.
How should US400 be specified?
Specify grade (US400), thickness, PSA option if required, compliance requirements (AMS 3196, FAR 25.853), dimensional tolerances, and finished format.
