70 Durometer Premium Nitrile Sheet
70 Durometer Premium Nitrile Sheet is a premium grade Nitrile (NBR/Buna N) rubber sheet with a durometer of 70 Shore A, a minimum tensile strength of 2,500 psi, and a minimum elongation of 300%. The material delivers a tightly controlled compression set of 25% maximum at 22 hours/100°C and an extended service temperature range of -40°F to +200°F (-40°C to +93°C). Full ASTM D471 resistance data is provided for Oil #1, Oil #3, Fuel A, Fuel B, and Water, and the material is rated to ASTM D2000: 2BG725A14B14EA14EF11EF21EO14EO34. Available – cloth-inserted (CI) construction for enhanced dimensional stability.
Key Properties
- Durometer, Shore “A”: 70 — ASTM D2240
- Tensile Strength, psi: 2500 min. — ASTM D412
- Ultimate Elongation, %: 300 min. — ASTM D412
- Compression Set, 22 hrs @ 100°C (212°F): 25% max. — ASTM D395 Method B
- Specific Gravity, g/cc: 1.18
- Service Temperature: -40°F to +200°F (-40°C to +93°C)
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- Specifications
- Applications
- General Info
- FAQs
Physical Properties
| Property | Value | Test Method |
| Polymer | Nitrile (NBR) (Buna N) | — |
| Grade | Premium | — |
| Color | Black | — |
| Finish | Smooth | — |
| Specific Gravity, g/cc | 1.18 | — |
| Hardness, Shore A | 70 | ASTM D2240 |
| Tensile Strength, psi | 2500 min. | ASTM D412 |
| Ultimate Elongation, % | 300 min. | ASTM D412 |
| Compression Set, 22 hrs @ 100°C (212°F) | 25% max. | ASTM D395 Method B |
| Temperature Range (general guideline) | -40°F to +200°F (-40°C to +93°C) | — |
Aging Performance
| Property | Value | Test Method |
| Heat Aging, 70 hrs @ 100°C (212°F) — Hardness Change | ±15 points max. | ASTM D573 |
| Heat Aging, 70 hrs @ 100°C (212°F) — Tensile Change | ±30% max. | ASTM D573 |
| Heat Aging, 70 hrs @ 100°C (212°F) — Elongation Change | -50% max. | ASTM D573 |
Chemical Resistance
| Property | Value | Test Method |
| Oil Resistance, Oil #3, 70 hrs @ 100°C (212°F) — Hardness Change | -10 to +5 points | ASTM D471 |
| Oil Resistance, Oil #3, 70 hrs @ 100°C (212°F) — Tensile Change | -45% max. | ASTM D471 |
| Oil Resistance, Oil #3, 70 hrs @ 100°C (212°F) — Elongation Change | -45% max. | ASTM D471 |
| Oil Resistance, Oil #3, 70 hrs @ 100°C (212°F) — Volume Change | 0 to 25% | ASTM D471 |
| Oil Resistance, Oil #1, 70 hrs @ 100°C (212°F) — Hardness Change | -5 to +10 points | ASTM D471 |
| Oil Resistance, Oil #1, 70 hrs @ 100°C (212°F) — Tensile Change | -25% max. | ASTM D471 |
| Oil Resistance, Oil #1, 70 hrs @ 100°C (212°F) — Elongation Change | -45% max. | ASTM D471 |
| Oil Resistance, Oil #1, 70 hrs @ 100°C (212°F) — Volume Change | -10 to +5% | ASTM D471 |
| Fuel Resistance, Fuel A, 70 hrs @ 23°C (73.4°F) — Hardness Change | ±10 points | ASTM D471 |
| Fuel Resistance, Fuel A, 70 hrs @ 23°C (73.4°F) — Tensile Change | -25% max. | ASTM D471 |
| Fuel Resistance, Fuel A, 70 hrs @ 23°C (73.4°F) — Elongation Change | -25% max. | ASTM D471 |
| Fuel Resistance, Fuel A, 70 hrs @ 23°C (73.4°F) — Volume Change | -5 to +10% | ASTM D471 |
| Fuel Resistance, Fuel B, 70 hrs @ 23°C (73.4°F) — Hardness Change | 0 to -30 points | ASTM D471 |
| Fuel Resistance, Fuel B, 70 hrs @ 23°C (73.4°F) — Tensile Change | -60% max. | ASTM D471 |
| Fuel Resistance, Fuel B, 70 hrs @ 23°C (73.4°F) — Elongation Change | -60% max. | ASTM D471 |
| Fuel Resistance, Fuel B, 70 hrs @ 23°C (73.4°F) — Volume Change | 0 to +40% | ASTM D471 |
| Water Resistance, Water, 70 hrs @ 100°C (212°F) — Hardness Change | ±10 points | ASTM D471 |
| Water Resistance, Water, 70 hrs @ 100°C (212°F) — Volume Change | ±15% max. | ASTM D471 |
Compliance
- ASTM D2000: 2BG725A14B14EA14EF11EF21EO14EO34 — Compliant
- High-strength oil and fuel system seals and gaskets in hydraulic and fluid-handling equipment
- Hydraulic and pneumatic system sealing in demanding industrial environments requiring firm, high-tensile gasketing
- Automotive fuel system gasketing in direct fuel and oil contact service
- Die-cut premium NBR components for structural bolted sealing joints
- Industrial sealing in multi-fluid environments including petroleum oils, hydrocarbon fuels, and water
Common industries: Industrial manufacturing, hydraulic systems, automotive, oil and gas, power generation, machinery and equipment.
70 Durometer Premium Nitrile Sheet is the highest-durometer, highest-tensile grade in the premium nitrile sheet line — a firm, high-strength NBR (Buna N) elastomer engineered for structural sealing joints, hydraulic system components, and multi-fluid industrial environments where mechanical robustness and documented chemical resistance are required.
At 70 Shore A with a minimum tensile strength of 2,500 psi and a 25% maximum compression set at 22 hours/100°C, it provides the tightest mechanical performance profile in the product range while maintaining an extended service temperature span of -40°F to +200°F (-40°C to +93°C). Available in 36″ and 48″ widths from 1/32″ to 1/2″ thickness in a smooth black powdered finish.
70 Durometer Premium Nitrile Sheet carries the most extensive fluid resistance dataset of any grade in the line, with full ASTM D471 test results across five fluid exposures: Oil #3, Oil #1, Fuel A, Fuel B, and Water — covering the range from light petroleum oil through heavy aromatic fuel blends and aqueous environments.
Fuel B resistance (0 to -30 points hardness change; volume change 0 to +40%) reflects the material’s known sensitivity to high-aromatic fuel exposure at this durometer, which is a normal characteristic of NBR elastomers and should be evaluated against application fuel composition requirements. Heat aging per ASTM D573 at 70 hours/100°C confirms controlled property retention within ±15 hardness points, ±30% tensile, and -50% elongation.
Compliant with ASTM D2000: 2BG725A14B14EA14EF11EF21EO14EO34.
What differentiates 70 Durometer Premium Nitrile Sheet from the 50 durometer premium grade?
70 Durometer Premium Nitrile Sheet is firmer, stronger, and more extensively tested than the 50 durometer premium grade. It delivers 2,500 psi minimum tensile strength vs. 2,000 psi, and at 70 Shore A is significantly less conformable — appropriate for structural gasket joints where resistance to extrusion, higher clamping loads, and dimensional stability under pressure are the primary requirements. It also adds Fuel B and Water resistance data to the ASTM D471 test suite, providing documented performance across five fluid exposures vs. three for the 50 durometer grade.
Why does compression set matter for high-durometer premium nitrile sheet?
At higher durometers, rubber gaskets are used in joints with higher clamping loads and often in more demanding thermal and chemical environments. A tight compression set limit — 25% maximum at 22 hours/100°C for 70 Durometer Premium Nitrile Sheet — ensures the material retains adequate elastic recovery after sustained compression to continue generating residual sealing force as the joint relaxes over its service life. This is critical in hydraulic, fuel system, and high-pressure industrial sealing applications where gasket relaxation directly impacts system integrity.
What is the service temperature range for 70 Durometer Premium Nitrile Sheet?
-40°F to +200°F (-40°C to +93°C), as listed on the TDS (general guideline).
Is 70 Durometer Premium Nitrile Sheet suitable for fuel system applications?
Yes, with application-specific evaluation. Documented ASTM D471 data covers Fuel A (volume change -5 to +10%, 70 hrs/23°C) and Fuel B (volume change 0 to +40%, 70 hrs/23°C). The higher volume swell in Fuel B reflects NBR's known sensitivity to high-aromatic fuel blends, which is a normal characteristic of the polymer family. Application fuel composition should be evaluated against the Fuel B data when aromatic content is significant.
How should 70 Durometer Premium Nitrile Sheet be specified?
Specify 70 Durometer Premium Nitrile Sheet, thickness, width (36" or 48"), compliance requirement (ASTM D2000: 2BG725A14B14EA14EF11EF21EO14EO34), dimensional tolerances, and finished format.
