70 Durometer Natural Rubber Sheet
70 Durometer Natural Rubber Sheet is a firm-durometer polyisoprene elastomer sheeting compound offering a service temperature range of -70 to +180°F and elongation of 500% to 900%. Natural rubber delivers superior resilience, tensile strength, and excellent adhesion to fabrics and metals — performance characteristics that make it the material of choice for dynamic applications requiring energy absorption, abrasion resistance, and flex-crack resistance. At 70 Shore A, this grade provides the highest compression resistance in the Natural Rubber Sheet line and is suited for high-load sealing, heavy-duty vibration isolation, and abrasion-resistant applications.
Key Properties
- Hardness, Shore A: 70 ± 5 (ASTM D2240)
- Elongation: 500–900%
- Service Temperature Range: -70 to +180°F
- ASTM D2000 / SAE J200 Classification: AA
- ASTM D-1418 Designation: NR
- Recommended Shelf Life: 3 years
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- Specifications
- Applications
- General Info
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Physical Properties
| Property | Value | Test Method |
| Hardness, Shore A | 70 ± 5 | ASTM D2240 |
| Elongation, % | 500–900 | — |
| Temperature Range | -70 to +180°F | — |
| ASTM D2000 / SAE J200 Classification | AA | — |
| ASTM D-1418 Designation | NR | — |
| MIL-R-3065 / SAE J-14 / MIL-STD-417 Classification | RN | — |
| Recommended Shelf Life | 3 years | — |
Mechanical Properties
| Property | Rating |
| Compression Set | Excellent |
| Abrasion Resistance | Excellent |
| Impact Resistance | Excellent |
| Resilience (Cold) | Excellent |
| Resilience (Hot) | Excellent |
| Flex Cracking Resistance | Excellent |
| Tear Resistance | Very Good |
| Flame Resistance | Poor |
Environmental Properties
| Property | Rating |
| Ozone Resistance | Poor |
| Weather Resistance | Poor to Fair |
| Sunlight Resistance | Poor |
| Steam Resistance | Fair to Good |
| Water Resistance | Very Good |
| Oxidation Resistance | Good |
| Gas Permeability | Fair to Good |
| Radiation Resistance | Fair to Good |
Compliance
- ASTM D2000 / SAE J200 Classification AA — Compliant
- MIL-R-3065 / SAE J-14 / MIL-STD-417 Classification RN — Compliant
- Automotive gaskets and seals
- Industrial belts and vibration dampers
- Construction components and expansion joints
- Conveyor systems and machine mounts
- Abrasion-resistant liners and wear pads
Common industries: Automotive, General Industrial, Construction, Material Handling, OEM Equipment.
70 Durometer Natural Rubber Sheet is the firmest grade in the Natural Rubber 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 compressive loads while retaining the Excellent resilience, abrasion resistance, and flex-crack resistance that distinguish natural rubber from synthetic alternatives.
The high elongation range of 500% to 900% is maintained even at 70 Shore A, providing energy absorption capability not typically available from synthetic elastomers at comparable hardness.
The -70 to +180°F service temperature range and Excellent cold and hot resilience support dynamic loading applications across a wide thermal range, including heavy-duty machine mounts, conveyor wear components, and high-load expansion joints. Natural rubber’s outstanding adhesion to fabrics and metals supports bonded and vulcanized-to-metal constructions common in this durometer range. Note that natural rubber has poor resistance to ozone, UV, sunlight, petroleum-based oils, and flame — application environments should be evaluated accordingly.
What differentiates 70 Durometer Natural Rubber Sheet from the 40 Durometer, 50 Durometer, and 60 Durometer grades?
70 Durometer Natural Rubber Sheet is the firmest grade in the Natural Rubber Sheet line at 70 Shore A, providing the highest compression resistance and the greatest resistance to extrusion and deformation under load. 60 Durometer Natural Rubber Sheet is the mid-range grade for general industrial applications. 50 Durometer Natural Rubber Sheet and 40 Durometer Natural Rubber Sheet are the softer grades preferred where maximum conformability and flexibility are the primary selection criteria.
Why is a firm durometer natural rubber grade preferred in high-load dynamic applications?
At 70 Shore A, this material resists compression set and extrusion under sustained high loads while retaining the Excellent resilience that makes natural rubber effective in dynamic service. Softer grades may deflect excessively under high compressive loading, reducing sealing effectiveness or allowing the material to migrate out of the joint. The firm durometer also supports bonded-to-metal and vulcanized constructions where the rubber element must maintain its form under combined static and dynamic loading.
What is the service temperature range for 70 Durometer Natural Rubber Sheet?
The service temperature range is -70 to +180°F, as listed on the Technical Datasheet.
What are the limitations of natural rubber in outdoor or chemical environments?
Natural rubber has poor resistance to ozone, sunlight, UV exposure, and weathering, and is not recommended for contact with petroleum-based oils, fuels, gasoline, mineral oil, or most hydrocarbon solvents. Applications involving these exposures should consider a synthetic elastomer such as EPDM or nitrile. Salt water and sodium hydroxide are rated as having little or minor effect and are acceptable.
How should 70 Durometer Natural Rubber Sheet be specified?
Specify grade (70 Durometer Natural Rubber Sheet), thickness, applicable classification (ASTM D2000 AA or MIL-R-3065 RN as required), dimensional tolerances, and finished format.
