Cork Composition (Cork-Rubber) NBR-CORK
Matrix · default condition
ASTM F104
Default choice for oil, fuel and hydraulic-fluid gaskets: transformer covers, oil pans, gearbox and pump flanges.
Values for the NBR-CORK condition
Other Cork Composition (Cork-Rubber) tempers and conditions
Cork Composition (Cork-Rubber) is listed in 4 conditions; see the grade overview at Cork Composition (Cork-Rubber).
Compare all 4 conditionsHide
| Condition · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness | Conductivity |
|---|---|---|---|---|---|---|
silicone rubber bonded cork composition (high temperature) | Use when continuous service above 150 °C or wide-temperature-range sealing (ovens, transformers, aerospace ducts) is required. | — | 1 | 10 | — | 0.12 W/m·K |
styrene-butadiene bonded cork composition (general purpose) | Lowest-cost grade for water, air and vibration-damping pads where oil resistance is not needed. | — | 1 | 15 | — | 0.09 W/m·K |
Neoprene (chloroprene) bonded cork composition | Pick for weathering, refrigerant, mild acid/alkali and outdoor electrical enclosure sealing. | — | 2 | 14 | — | 0.1 W/m·K |
NBR-CORKDefaultThis page nitrile rubber bonded cork composition (ASTM F104 Type 5, oil resistant) | Default choice for oil, fuel and hydraulic-fluid gaskets: transformer covers, oil pans, gearbox and pump flanges. | — | 2 | 12 | — | 0.1 W/m·K |
What is Cork Composition (Cork-Rubber) NBR-CORK?
Cork Composition (Cork-Rubber) NBR-CORK is Cork Composition (Cork-Rubber) in the NBR-CORK condition — default choice for oil, fuel and hydraulic-fluid gaskets: transformer covers, oil pans, gearbox and pump flanges. Cork Composition (Cork-Rubber) NBR-CORK has a tensile strength of 2 MPa (0.305 ksi), weaker than 91% of natural material grades. Elongation at break is 12% and the elastic modulus is 0.03 GPa (0.0044 Msi). Cork Composition (Cork-Rubber) NBR-CORK has a density of 0.75 g/cm³ (0.0271 lb/in³), heavier than 65% of natural material grades.
Advantages
- Ductile — tolerates forming and impact — 12%, better than 83% of natural material grades
- High service temperature — 120°C (248 °F), better than 79% of natural material grades
- Good corrosion resistance — 70/100, better than 78% of natural material grades
Limitations
- Low stiffness — 0.03 GPa (0.0044 Msi), worse than 89% of natural material grades
- Poor heat conductor — 0.1 W/m·K (0.0578 BTU/hr·ft·°F), worse than 84% of natural material grades
- High embodied carbon — 1.5 kg CO₂/kg, worse than 83% of natural material grades
Cork Composition (Cork-Rubber) NBR-CORK properties
Typical room-temperature values for Cork Composition (Cork-Rubber) NBR-CORK; 12 are specific to this condition. Other listed values are Cork Composition (Cork-Rubber) reference data and may not represent this condition. Bars are the position among natural material grades.
Physical2
Cork Composition (Cork-Rubber) NBR-CORK has a density of 0.75 g/cm³ (0.0271 lb/in³), heavier than 65% of natural material grades.
Mechanical6
Cork Composition (Cork-Rubber) NBR-CORK has a tensile strength of 2 MPa (0.305 ksi), weaker than 91% of natural material grades. Elongation at break is 12% and the elastic modulus is 0.03 GPa (0.0044 Msi).
Thermal5
Cork Composition (Cork-Rubber) NBR-CORK is rated for continuous service to 120°C (248 °F). It conducts heat at 0.1 W/m·K (0.0578 BTU/hr·ft·°F), worse than 84% of natural material grades. Thermal expansion is 120 µm/m·K (66.7 µin/in·°F).
Electrical2
Cork Composition (Cork-Rubber) NBR-CORK is an electrical insulator with a dielectric strength of 4 kV/mm (101.6 V/mil) and a resistivity of 1×10⁹ Ω·m.
Chemical & Environmental1
Corrosion resistance is very good (70/100), better than 78% of natural material grades.
Sustainability4
Producing a kilogram of Cork Composition (Cork-Rubber) NBR-CORK takes about 18 MJ of energy and emits 1.5 kg of CO₂ — more than 81% of natural material grades. Typical recycled content is 40%.
Manufacturability1
Cork Composition (Cork-Rubber) NBR-CORK's machinability is excellent (85/100, better than 63% of natural material grades).
Common Calculations4
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with Cork Composition (Cork-Rubber) NBR-CORK
Is Cork Composition (Cork-Rubber) easy to machine?
Best die-cut, steel-rule cut, punched or water-jet cut; router/knife cutting works but avoid hot high-speed tools that smear the binder.
Can Cork Composition (Cork-Rubber) be welded?
Not weldable; joints are made with butt or scarf splices bonded by contact/CR adhesive or by vulcanized splicing tape.
Can Cork Composition (Cork-Rubber) be formed, bent or molded?
Supplied as calendered/press-cured sheet or slit rolls; it conforms to irregular flanges at low bolt load — do not over-compress beyond about 50 % thickness.
What surface finishes work on Cork Composition (Cork-Rubber)?
Optional silicone or wax-based surface coating to reduce sticking and improve fluid release; adhesive backing (PSA) is common for stick-in-place gaskets.
Cork Composition (Cork-Rubber) chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| cork granulateground Quercus suber bark, typical 0.5–3 mm granule size | 45 – 75 | 60 |
| curatives, fillers and processing aidssulfur/peroxide cure system, carbon black or mineral filler | 2 – 8 | 5 |
| elastomer binder (NBR/CR/SBR/VMQ)type sets oil/temperature resistance | ≥ 20 (balance) | — |
Cork Composition (Cork-Rubber) NBR-CORK — frequently asked
What is Cork Composition (Cork-Rubber) NBR-CORK used for?
Cork Composition (Cork-Rubber) NBR-CORK is typically used for engine gaskets, oil seals, expansion joints and vibration pads. In short: conforms at low bolt load; oil-resistant cork gasket sheet; ASTM F104 line-call grades.
What is the tensile strength of Cork Composition (Cork-Rubber) NBR-CORK?
Cork Composition (Cork-Rubber) NBR-CORK has a typical tensile strength of 2 MPa (0.305 ksi) — weaker than 91% of natural material grades. Strength varies by condition: see the 4 listed tempers.
Is Cork Composition (Cork-Rubber) NBR-CORK easy to machine?
Yes — machinability is rated excellent (85/100, better than 63% of natural material grades). Best die-cut, steel-rule cut, punched or water-jet cut; router/knife cutting works but avoid hot high-speed tools that smear the binder.
Can Cork Composition (Cork-Rubber) NBR-CORK be welded?
Not weldable; joints are made with butt or scarf splices bonded by contact/CR adhesive or by vulcanized splicing tape.
What surface finishes work on Cork Composition (Cork-Rubber) NBR-CORK?
Optional silicone or wax-based surface coating to reduce sticking and improve fluid release; adhesive backing (PSA) is common for stick-in-place gaskets.
Can Cork Composition (Cork-Rubber) NBR-CORK be formed, bent or molded?
Supplied as calendered/press-cured sheet or slit rolls; it conforms to irregular flanges at low bolt load — do not over-compress beyond about 50 % thickness.
What is the maximum service temperature of Cork Composition (Cork-Rubber) NBR-CORK?
Cork Composition (Cork-Rubber) NBR-CORK is rated for continuous use to about 120°C (248 °F). Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- ASTM F104 — Standard Classification System for Nonmetallic Gasket Materials — ASTM International (2023)
- ASTM F36 / F152 / F146 — compressibility-recovery, tensile and fluid immersion tests for gasket materials — ASTM International (2021)
- Cork-rubber gasket sheet datasheets (nitrile, neoprene, SBR and silicone bonded grades) — Gasket sheet producers (2023)
- Cork: Biology, Production and Uses (properties of cork composites) — Elsevier (2015)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.