Overview
NBR (Nitrile Butadiene Rubber), also known as Buna-N® or Nitrile Rubber, is one of the most widely used synthetic elastomers due to its excellent oil resistance, fuel resistance, abrasion resistance, mechanical strength, and cost-effectiveness.
NBR is produced through the copolymerization of acrylonitrile and butadiene. By varying the acrylonitrile content, manufacturers can optimize the balance between oil resistance, flexibility, and low-temperature performance.
NBR is widely used in:
- Automotive Systems
- Hydraulic Equipment
- Fuel Handling Systems
- Industrial Machinery
- Oil & Gas Equipment
- Pneumatic Components
- Sealing Applications
- Aerospace Support Systems
Because of its excellent resistance to petroleum-based fluids, NBR is considered the industry-standard elastomer for oil and fuel sealing applications.
Material Specification
| Property | Value |
|---|---|
| Material Designation | NBR |
| Full Name | Nitrile Butadiene Rubber |
| Common Names | Nitrile Rubber, Buna-N |
| Material Family | Synthetic Rubber Elastomer |
| Density | 1.00–1.35 g/cm³ |
| Appearance | Black, White, Colored |
| Hardness Range | Shore A 30–95 |
| Typical Manufacturing Methods | Compression Molding, Injection Molding, Extrusion |
| Standard Forms | Sheets, Rolls, Tubes, O-Rings, Molded Parts |
Chemical Composition
NBR is composed of acrylonitrile and butadiene monomers.
| Component | Function |
|---|---|
| Acrylonitrile (ACN) | Oil & Fuel Resistance |
| Butadiene | Flexibility & Elasticity |
| Carbon Black | Reinforcement |
| Vulcanizing Agents | Crosslinking |
| Processing Additives | Performance Enhancement |
Higher acrylonitrile content generally improves oil resistance while reducing low-temperature flexibility.
Common NBR Grades
| Grade | Characteristics |
|---|---|
| Low ACN NBR (18–25%) | Better Low-Temperature Flexibility |
| Medium ACN NBR (26–35%) | Balanced Performance |
| High ACN NBR (36–50%) | Maximum Oil Resistance |
| Food Grade NBR | FDA-Compliant Applications |
| Hydrogenated NBR (HNBR) | Enhanced Heat & Chemical Resistance |
Mechanical Properties
Typical Values
| Property | Value |
|---|---|
| Tensile Strength | 10–25 MPa |
| Elongation at Break | 200–600% |
| Tear Strength | 20–50 kN/m |
| Compression Set | Good |
| Hardness | Shore A 30–95 |
| Resilience | Good |
Typical Mechanical Performance
| Property | Performance |
|---|---|
| Abrasion Resistance | Excellent |
| Flexibility | Good |
| Tear Resistance | Excellent |
| Fatigue Resistance | Good |
NBR offers superior wear resistance compared with many general-purpose elastomers.
Physical Properties
| Property | Value |
|---|---|
| Density | 1.00–1.35 g/cm³ |
| Water Absorption | Very Low |
| Thermal Conductivity | 0.20–0.30 W/m·K |
| Gas Permeability | Low |
| Abrasion Resistance | Excellent |
Its low permeability makes NBR ideal for sealing applications.
Thermal Properties
| Property | Value |
|---|---|
| Continuous Service Temperature | -30°C to 120°C |
| Premium Grades | Up to 135°C |
| Short-Term Temperature Resistance | Up to 150°C |
| Brittleness Temperature | Approximately -40°C |
NBR performs well in moderate-temperature industrial environments.
Strength-to-Weight Ratio
| Material | Density (g/cm³) | Tensile Strength |
|---|---|---|
| NBR | 1.20 | 18 MPa |
| EPDM | 1.10 | 12 MPa |
| Silicone | 1.20 | 8 MPa |
| FKM (Viton) | 1.80 | 12 MPa |
NBR combines excellent mechanical performance with moderate cost.
Chemical Resistance
| Chemical Environment | Performance |
|---|---|
| Petroleum Oils | Outstanding |
| Hydraulic Fluids | Outstanding |
| Diesel Fuel | Outstanding |
| Gasoline | Excellent |
| Lubricants | Outstanding |
| Water | Good |
| Alcohols | Moderate |
| Ozone | Poor |
| Strong Acids | Poor |
NBR is specifically designed for petroleum-based fluid environments.
Oil & Fuel Resistance
| Property | Performance |
|---|---|
| Engine Oil Resistance | Outstanding |
| Hydraulic Oil Resistance | Outstanding |
| Fuel Resistance | Excellent |
| Lubricant Resistance | Outstanding |
| Grease Resistance | Outstanding |
NBR is one of the most commonly used elastomers for fuel and oil sealing systems.
Weather & UV Resistance
| Property | Performance |
|---|---|
| UV Resistance | Poor |
| Ozone Resistance | Poor |
| Outdoor Durability | Moderate |
| Weather Aging Resistance | Moderate |
Outdoor applications often require protective additives or alternative elastomers such as EPDM.
Electrical Properties
| Property | Value |
|---|---|
| Volume Resistivity | >10¹¹ Ω·cm |
| Dielectric Strength | 10–20 kV/mm |
| Dielectric Constant | 4.0–6.0 |
| Arc Resistance | Moderate |
NBR can be used in certain electrical insulation applications but is not typically selected for dielectric performance.
Compression Set Resistance
| Property | Performance |
|---|---|
| Seal Retention | Excellent |
| Compression Recovery | Good |
| Long-Term Gasket Performance | Good |
| O-Ring Performance | Outstanding |
NBR is widely used for dynamic and static sealing applications.
Wear & Abrasion Resistance
| Property | Performance |
|---|---|
| Abrasion Resistance | Outstanding |
| Wear Resistance | Excellent |
| Dynamic Sealing Performance | Excellent |
| Mechanical Durability | Excellent |
This makes NBR ideal for hydraulic and pneumatic systems.
Manufacturing Characteristics
| Manufacturing Process | Rating |
|---|---|
| Compression Molding | Outstanding |
| Injection Molding | Excellent |
| Extrusion | Outstanding |
| Transfer Molding | Excellent |
| Overmolding | Good |
NBR supports economical production across a wide range of component sizes.
International Equivalent Standards
| Standard | Equivalent |
|---|---|
| ASTM D2000 | NBR |
| ISO | NBR |
| DIN | NBR-Kautschuk |
| JIS | NBR Rubber |
| GB/T (China) | 丁腈橡胶 |
| FDA | Food Grade Versions Available |
Available Forms
| Product Type | Availability |
|---|---|
| Sheets | Yes |
| Rolls | Yes |
| Tubes | Yes |
| O-Rings | Yes |
| Gaskets | Yes |
| Molded Parts | Yes |
Typical Applications
Automotive Industry
- Fuel System Seals
- O-Rings
- Gaskets
- Hydraulic Components
Oil & Gas Industry
- Valve Seals
- Pump Components
- Fuel Transfer Systems
- Oil Handling Equipment
Industrial Machinery
- Hydraulic Seals
- Pneumatic Components
- Rollers
- Flexible Couplings
Aerospace Support Systems
- Fuel System Components
- Hydraulic Seals
- Maintenance Equipment
Agricultural Equipment
- Hydraulic Hoses
- Fuel Handling Components
- Machinery Seals
General Engineering
- O-Rings
- Gaskets
- Wear Pads
- Vibration Dampers
Advantages
Outstanding Oil Resistance
Excellent compatibility with petroleum-based oils and lubricants.
Superior Fuel Resistance
Widely used in gasoline and diesel systems.
Excellent Abrasion Resistance
Suitable for demanding mechanical environments.
Good Mechanical Strength
Reliable performance in industrial sealing applications.
Low Gas Permeability
Excellent sealing capability.
Cost-Effective
Provides excellent performance at a competitive cost.
Limitations
Poor UV Resistance
Not recommended for long-term outdoor exposure.
Poor Ozone Resistance
May crack when exposed to ozone-rich environments.
Moderate Temperature Capability
Not suitable for extreme high-temperature applications.
Limited Chemical Resistance
Not resistant to strong oxidizers, ketones, and certain solvents.
Comparison with Common Elastomers
| Property | NBR | EPDM | Silicone | FKM (Viton) |
|---|---|---|---|---|
| Oil Resistance | Outstanding | Poor | Moderate | Outstanding |
| Fuel Resistance | Excellent | Poor | Poor | Outstanding |
| UV Resistance | Poor | Outstanding | Outstanding | Good |
| Temperature Resistance | Good | Excellent | Outstanding | Outstanding |
| Cost | Low | Low | High | Very High |
Comparison with EPDM
| Property | NBR | EPDM |
|---|---|---|
| Oil Resistance | Better | |
| Fuel Resistance | Better | |
| Weather Resistance | Lower | |
| UV Resistance | Lower | |
| Water Resistance | Lower |
NBR is selected for oil and fuel applications, while EPDM is preferred for outdoor and water-exposed environments.
Available Surface Finishes
Standard Finishes
- Matte Finish
- Smooth Finish
- Molded Finish
Functional Finishes
- Oil Resistant Finish
- Fuel Resistant Finish
- Dynamic Sealing Finish
Specialty Grades
- Low ACN NBR
- Medium ACN NBR
- High ACN NBR
- Food Grade NBR
- HNBR
Frequently Asked Questions (FAQ)
What is NBR?
NBR (Nitrile Butadiene Rubber) is a synthetic elastomer known for outstanding oil, fuel, and abrasion resistance.
What is NBR used for?
Typical applications include:
- O-Rings
- Fuel Seals
- Hydraulic Components
- Automotive Systems
- Industrial Machinery
Is NBR oil resistant?
Yes. NBR provides excellent resistance to petroleum oils, lubricants, and hydraulic fluids.
Is NBR suitable for fuel systems?
Yes. NBR is one of the most widely used elastomers in gasoline and diesel fuel systems.
Is NBR weather resistant?
No. NBR has limited UV and ozone resistance compared with EPDM and Silicone.
Why choose NBR?
Because it combines:
- Outstanding Oil Resistance
- Excellent Fuel Resistance
- Superior Abrasion Resistance
- Good Mechanical Strength
- Cost Efficiency
What is the difference between NBR and HNBR?
HNBR (Hydrogenated NBR) provides significantly better heat resistance, ozone resistance, and chemical resistance than standard NBR.
Does GCNOV provide NBR manufacturing services?
Yes. GCNOV provides:
- NBR Compression Molding
- NBR Injection Molding
- Custom O-Ring Manufacturing
- Fuel System Components
- Hydraulic Seal Production
- Prototype Development
- Low-Volume Production
- Mass Production