70 Durometer Butyl (IIR) Sheet
70 Durometer Butyl (IIR) Sheet is a firm-durometer butyl rubber sheeting compound meeting the requirements of ASTM D2000 M1AA707, with a service temperature range of -40 to +180°F, a tensile strength of 1015 psi, and elongation of 200%. The material is compliant with REACH, RoHS, and California Proposition 65 and is manufactured in the USA. At 70 Shore A, this grade provides the highest compression resistance in the Butyl (IIR) Sheet line and is suited for sealing applications where dimensional stability under load, resistance to extrusion, and the inherent low permeability of butyl rubber are all required.
Key Properties
- Hardness, Shore A: 70 ± 5 (ASTM D2240)
- Tensile Strength: 1015 psi (ASTM D412)
- Elongation: 200% (ASTM D412)
- Service Temperature Range: -40 to +180°F
- Specification: ASTM D2000 M1AA707
- Compliance: REACH, RoHS, California Proposition 65
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- Specifications
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- General Info
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Physical Properties
| Property | Typical Value | Test Method |
| Hardness, Shore A | 70 ± 5 | ASTM D2240 |
| Tensile Strength, psi | 1015 | ASTM D412 |
| Elongation, % | 200 | ASTM D412 |
| Temperature Range | -40 to +180°F | — |
Standard Dimensions
| Property | Value |
| Thickness Range | 1/32″ – 1/4″ |
| Standard Widths | 36″, 48″ |
| Estimated Weight Per Linear Foot (1/8″ x 36″) | 2.3 lb |
Compliance
- ASTM D2000 M1AA707 — Compliant
- REACH — Compliant
- RoHS — Compliant
- California Proposition 65 — Compliant
- High-load flange gaskets and compression seals
- Chemical-resistant seals requiring firm durometer
- Pharmaceutical and food processing equipment seals
- Steam system gaskets and seals
- Gas and vapor containment sealing
Common industries: Chemical Processing, Pharmaceutical, Food & Beverage, Steam & HVAC Systems, General Industrial.
70 Durometer Butyl (IIR) Sheet is the firmest grade in the Butyl (IIR) Sheet line, offering 70 Shore A hardness and the highest compression resistance in the series. At this durometer, the material resists extrusion and deformation under high bolt loads, maintaining a stable sealing cross-section through the service life of the joint. This makes it the appropriate selection for high-load flange gasket applications and wherever compressive forces are elevated enough to cause softer grades to flow or extrude beyond the sealing interface.
Butyl rubber provides inherent low gas and vapor permeability, excellent resistance to weathering, ozone, and UV exposure, and good resistance to polar chemicals, acids, and alkalis — all retained at the firmer durometer of this grade. Meeting ASTM D2000 M1AA707, this grade carries a documented material classification for procurement and engineering applications requiring a traceable specification. The material is REACH compliant, RoHS compliant, and California Proposition 65 compliant, and is manufactured in the USA.
What differentiates 70 Durometer Butyl (IIR) Sheet from the 40 Durometer, 50 Durometer, and 60 Durometer grades?
70 Durometer Butyl (IIR) Sheet is the firmest grade in the line at 70 Shore A, providing the highest compression resistance and the greatest resistance to extrusion under high bolt loads. 60 Durometer Butyl (IIR) Sheet is the mid-range grade meeting ASTM D2000 M1AA607. 50 Durometer Butyl (IIR) Sheet delivers the highest tensile strength (1100 psi) and elongation (450%) in the line. 40 Durometer Butyl (IIR) Sheet is the softest grade, offering maximum conformability for low-load or irregular-surface applications.
Why is a firm durometer butyl sheeting grade preferred in high-load sealing applications?
At higher bolt loads and clamping forces, softer elastomers can extrude beyond the sealing interface or take a permanent compression set that reduces sealing force over time. A 70 Shore A material resists these failure modes, maintaining its cross-section and sealing load through the service life of the joint. Selecting the correct hardness for the applied compressive load prevents both initial blow-out and long-term seal relaxation.
What is the service temperature range for 70 Durometer Butyl (IIR) Sheet?
The service temperature range is -40 to +180°F, as listed on the Technical Datasheet.
What chemical resistance properties does Butyl (IIR) rubber provide?
Butyl rubber offers excellent resistance to polar chemicals, dilute acids, alkalis, and ketones, as well as inherently low gas and vapor permeability. It is also highly resistant to weathering, ozone, and UV exposure. Butyl rubber is not recommended for petroleum oils, gasoline, or non-polar hydrocarbon solvents.
How should 70 Durometer Butyl (IIR) Sheet be specified?
Specify grade (70 Durometer Butyl (IIR) Sheet), thickness, ASTM D2000 M1AA707 if required by design documentation, compliance requirements, dimensional tolerances, and finished format.
