40 Durometer Industrial Grade Nitrile (NBR/SBR) Rubber Sheet
40 Durometer Industrial Grade Nitrile (NBR/SBR) Rubber Sheet is an industrial grade Nitrile/Styrene-Butadiene (NBR/SBR) blend rubber sheet with a durometer of 40 Shore A, a minimum tensile strength of 1,000 psi, and a minimum elongation of 500%. The material delivers a compression set of 40% maximum at 22 hours/100°C and a service temperature range of -20°F to +190°F (-29°C to +88°C). The sheet is supplied in a smooth black finish with powder, trimmed, in 48″ width. Available – cloth-inserted (CI) construction for enhanced dimensional stability.
Key Properties
- Durometer, Shore “A”: 40 — ASTM D2240
- Tensile Strength, psi: 1000 min. — ASTM D412
- Ultimate Elongation, %: 500 min. — ASTM D412
- Compression Set, 22 hrs @ 100°C (212°F): 40% max. — ASTM D395 Method B
- Specific Gravity, g/cc: 1.13
- Service Temperature: -20°F to +190°F (-29°C to +88°C)
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- Specifications
- Applications
- General Info
- FAQs
Physical Properties
| Property | Value | Test Method |
| Polymer | Nitrile, Styrene-Butadiene (NBR/SBR) | — |
| Grade | Industrial | — |
| Color | Black | — |
| Finish | Smooth | — |
| Specific Gravity, g/cc | 1.13 | — |
| Hardness, Shore A | 40 | ASTM D2240 |
| Tensile Strength, psi | 1000 min. | ASTM D412 |
| Ultimate Elongation, % | 500 min. | ASTM D412 |
| Compression Set, 22 hrs @ 100°C (212°F) | 40% max. | ASTM D395 Method B |
| Temperature Range (general guideline) | -20°F to +190°F (-29°C to +88°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) — Volume Change | 80% max. | ASTM D471 |
Compliance
- ASTM D2000: 1BE410 — Compliant
- General industrial gaskets and sealing components in oil- and grease-exposed environments
- Equipment sealing where soft, conformable gasketing material is required under low clamping loads
- Conveyor and machinery surface padding and wear protection
- Die-cut industrial gaskets and anti-vibration pads
- General-purpose sheet stock for cutting, fabrication, and converting
Common industries: Industrial manufacturing, machinery and equipment, maintenance and repair operations, general industry.
40 Durometer Industrial Grade Nitrile (NBR/SBR) Rubber Sheet is a soft, conformable industrial elastomer sheet formulated as a Nitrile/Styrene-Butadiene (NBR/SBR) blend to deliver practical oil and grease resistance for general industrial sealing, gasketing, and surface padding applications.
At 40 Shore A, it is the softest grade in the industrial nitrile line, providing high conformability and the highest elongation of the group — 500% minimum — which makes it well suited for die-cut gaskets that must seal against irregular or uneven mating surfaces under low or moderate clamping loads. The material is supplied in a smooth black powdered finish, trimmed to a 48″ width, and is within commercial sheet rubber gauge tolerances.
The material delivers a minimum tensile strength of 1,000 psi and a compression set of 40% maximum after 22 hours at 100°C, providing adequate long-term sealing force retention for industrial gasketing applications. Oil resistance in ASTM Oil #3 is 80% maximum volume change after 70 hours at 100°C, confirming suitability for incidental contact with petroleum-based industrial oils and greasy fluids.
Heat aging per ASTM D573 at 70 hours/100°C shows controlled hardness change of ±15 points, tensile change of ±30% maximum, and elongation change of -50% maximum.
Compliant with ASTM D2000: 1BE410.
What differentiates 40 Durometer Industrial Grade Nitrile (NBR/SBR) Rubber Sheet from the higher-durometer nitrile grades?
At 40 Shore A, this is the softest and most conformable grade in the industrial nitrile line, with the highest elongation (500% minimum) and the lowest durometer. This makes it the appropriate selection for sealing against rough, irregular, or uneven mating surfaces where a softer, more pliable gasket material will conform and seal under lower clamping loads. Higher durometer grades provide greater tensile strength and firmness but sacrifice elongation and conformability.
Why does compression set matter for industrial nitrile gasketing?
Compression set measures how much of the original thickness a rubber gasket fails to recover after being held under compression. A high compression set means the gasket takes a permanent set in service and loses its ability to generate residual sealing force as the joint relaxes — which can lead to leaks over time. The 40% maximum compression set of 40 Durometer Industrial Grade Nitrile (NBR/SBR) Rubber Sheet (22 hrs @ 100°C) establishes the upper limit of permanent deformation acceptable for the industrial sealing applications this grade is designed for.
What is the service temperature range for 40 Durometer Industrial Grade Nitrile (NBR/SBR) Rubber Sheet?
-20°F to +190°F (-29°C to +88°C), as listed on the TDS (general guideline).
Is 40 Durometer Industrial Grade Nitrile (NBR/SBR) Rubber Sheet suitable for oil- and fluid-exposed applications?
Yes, for moderate oil and grease exposure. Oil resistance in ASTM Oil #3 at 70 hours/100°C shows a volume change of 80% maximum per ASTM D471, confirming suitability for incidental contact with petroleum-based industrial oils and greasy fluids. This grade is not intended for direct immersion in concentrated petroleum fuels or heavy industrial solvents.
How should 40 Durometer Industrial Grade Nitrile (NBR/SBR) Rubber Sheet be specified?
Specify 40 Durometer Industrial Grade Nitrile (NBR/SBR) Rubber Sheet, thickness (1/16", 1/8", 3/16", or 1/4"), compliance requirement (ASTM D2000: 1BE410), dimensional tolerances, and finished format.
