40 Durometer Butyl (IIR) Sheet
40 Durometer Butyl (IIR) Sheet is a soft-durometer chlorinated butyl rubber sheeting compound meeting the requirements of ASTM D2000 M1AA407, with a service temperature range of -40 to +180°F, a tensile strength of 1015 psi minimum, and elongation of 400% minimum. The material is compliant with REACH, RoHS, and California Proposition 65 and is manufactured in the USA. The soft durometer profile and high elongation make this grade well suited for applications requiring an IIR elastomer with maximum conformability and flexibility, including chemical-resistant gaskets, pharmaceutical seals, and steam system components.
Key Properties
- Hardness, Shore A: 40 ± 5 (ASTM D2240)
- Tensile Strength: 1015 psi min (ASTM D412)
- Elongation: 400% min (ASTM D412)
- Service Temperature Range: -40 to +180°F
- Specification: ASTM D2000 M1AA407
- Compliance: REACH, RoHS, California Proposition 65
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- Specifications
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Physical Properties
| Property | Required Value | Test Method |
| Hardness, Shore A | 40 ± 5 | ASTM D2240 |
| Tensile Strength, psi | 1015 min | ASTM D412 |
| Elongation, % | 400 min | 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″) | 2.09 lb |
Compliance
- ASTM D2000 M1AA407 — Compliant
- REACH — Compliant
- RoHS — Compliant
- California Proposition 65 — Compliant
- Chemical-resistant gaskets and seals
- Pharmaceutical and food processing equipment seals
- Steam system gaskets and seals
- Low-load flange seals requiring high conformability
- General industrial sealing applications
Common industries: Chemical Processing, Pharmaceutical, Food & Beverage, Steam & HVAC Systems, General Industrial.
40 Durometer Butyl (IIR) Sheet is the softest grade in the Butyl (IIR) Sheet line, offering 40 Shore A hardness and the highest elongation (400% minimum) in the series. The soft durometer profile and high elongation allow the material to conform readily to irregular or uneven sealing surfaces under low clamping loads, making it the preferred IIR grade for applications where surface finish or bolt-load limitations would prevent a firmer grade from seating effectively.
The butyl rubber polymer provides inherent low gas and vapor permeability, excellent resistance to weathering, ozone, and UV exposure, and good resistance to polar chemicals, acids, and alkalis — properties that support the material’s use in chemical processing, pharmaceutical, and steam system sealing environments.
Meeting ASTM D2000 M1AA407, this grade carries a documented material classification for procurement and engineering applications that require a traceable specification. The material is REACH compliant, RoHS compliant, and California Proposition 65 compliant, and is manufactured in the USA.
What differentiates 40 Durometer Butyl (IIR) Sheet from the 50 Durometer, 60 Durometer, and 70 Durometer grades?
40 Durometer Butyl (IIR) Sheet is the softest grade in the line at 40 Shore A, offering the highest elongation (400% min) and maximum conformability for low-load or irregular-surface sealing applications. 50 Durometer Butyl (IIR) Sheet delivers the highest tensile strength (1100 psi) and elongation (450%) in the line. 60 Durometer Butyl (IIR) Sheet is the mid-range grade with ASTM D2000 M1AA607 specification, and 70 Durometer Butyl (IIR) Sheet is the firmest grade for high-load, high-compression applications.
Why is a soft durometer butyl sheeting grade beneficial in sealing applications?
At 40 Shore A, this material conforms to surface irregularities under lower clamping forces than firmer grades, achieving an effective seal where higher-durometer materials would leave leak paths. This is especially important on cast or rough-finish flanges, pharmaceutical vessel connections, and low-bolt-load enclosures where compressive force is limited by the surrounding structure.
What is the service temperature range for 40 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 40 Durometer Butyl (IIR) Sheet be specified?
Specify grade (40 Durometer Butyl (IIR) Sheet), thickness, ASTM D2000 M1AA407 if required by design documentation, compliance requirements, dimensional tolerances, and finished format.
