kSil® US70
kSil® US70 is a solid silicone elastomer with a 70 Shore A durometer — the firmest grade in the kSil® US series — with a tensile strength of 8 MPa and an elongation of 300%. It meets AA-59588, AMS 3304, BfR XV, EC 1935/2004, FAR 25.853 Horizontal, FDA 21 CFR 177.2600, and FMVSS 302. The material is available in red-orange, black, and grey.
Key Properties
- Durometer: 70 Shore A (ISO 48-4)
- Tensile Strength: 8 MPa (ISO 37 Type 2)
- Elongation: 300% (ISO 37 Type 2)
- Compression Set, 24 Hours @ 150°C: 24% (ISO 815, 24h @150°C)
- Tear Strength: 19 N/mm (ASTM D624 Die B)
- Thermal Conductivity: 0.24 W/m·°C (ASTM C518)
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- Specifications
- Applications
- General Info
- FAQs
Physical Properties
| Property | Value | Test Method |
| Thermal Conductivity | 0.24 W/m·°C | ASTM C518 |
| Colors Available | Red-orange, Black, Grey | Visual |
Mechanical Properties
| Property | Value | Test Method |
| Durometer | 70 Shore A | ISO 48-4 |
| Tensile Strength | 8 MPa | ISO 37 Type 2 |
| Elongation | 300% | ISO 37 Type 2 |
| Tear Strength | 19 N/mm | ASTM D624 Die B |
| Compression Set — 24 Hours @ 150°C | 24% | ISO 815, 24h @150°C |
Compliance
- AA-59588 — Compliant
- AMS 3304 — Compliant
- BfR XV — Compliant
- EC 1935/2004 — Compliant
- FAR 25.853 Horizontal — Compliant
- FDA 21 CFR 177.2600 — Compliant
- FMVSS 302 — Compliant
- Firm gaskets and seals requiring maximum dimensional stability within the US solid silicone range
- Food contact components requiring simultaneous FDA and European BfR/EC compliance
- Aerospace sealing applications requiring AA-59588 and AMS 3304 qualification
- Aerospace flame compliance applications per FAR 25.853 Horizontal
- Automotive sealing components requiring FMVSS 302 compliance
Common industries: Aerospace, Automotive, Food Processing, Industrial Manufacturing.
kSil® US70 is the firmest grade in the kSil® US general purpose solid silicone series at 70 Shore A. Qualified to AMS 3304 and meeting AA-59588, it is designed for firm aerospace and automotive sealing applications where dimensional stability and resistance to deformation under load are the primary requirements. The grade carries a comprehensive compliance portfolio spanning aerospace, automotive, and international food contact standards.
US70 delivers a tensile strength of 8 MPa, an elongation of 300%, and a tear strength of 19 N/mm — the highest tear strength in the US solid silicone series. Compression set is 24% after 24 hours at 150°C per ISO 815. Thermal conductivity is 0.24 W/m·°C per ASTM C518. The material is available in red-orange, black, and grey.
Compliant with AA-59588, AMS 3304, BfR XV, EC 1935/2004, FAR 25.853 Horizontal, FDA 21 CFR 177.2600, and FMVSS 302.
What differentiates US70 from softer grades in the kSil® US solid silicone series?
US70 is the firmest grade in the US series at 70 Shore A, offering the highest dimensional stability and resistance to deformation under load within the range. It also exhibits the highest tear strength in the US solid silicone series at 19 N/mm. These characteristics make it suited for structural sealing and applications where maintaining the seal cross-section geometry under compressive stress is critical.
Why is compression set critical for solid silicone elastomers like US70?
Compression set measures the permanent deformation that remains after a material has been held under compressive load at elevated temperature. In sealing applications, high compression set leads to progressive loss of contact force and seal failure over time. US70 exhibits a compression set of 24% after 24 hours at 150°C per ISO 815.
What is the operating temperature range for US70?
No discrete operating temperature range is specified on the manufacturer's TDS for US70. The compression set test condition is 150°C. Contact H-O Products for service temperature guidance specific to your application.
Is US70 suitable for aerospace, automotive, or food contact environments?
Yes. US70 is qualified to AMS 3304 and meets AA-59588 and FAR 25.853 Horizontal for aerospace, is compliant with FMVSS 302 for automotive, and meets FDA 21 CFR 177.2600, BfR XV, and EC 1935/2004 for food contact applications.
How should US70 be specified?
Specify grade (US70), thickness, color (Red-orange, Black, or Grey), compliance requirements, dimensional tolerances, and finished format.
