NBR seals
NBR is the abbreviation for Nitrile Butadiene Rubber. Also known in German as Arcylnitril-Butadien-Kautschuk or Nitrilkautschuk. The material is a copolymer consisting of the two components arcylnitrile and 1,3-butadiene. NBR is one of the synthetic rubbers or polar elastomers that are produced on the basis of petrochemical raw materials. The material is marketed under various trade names, for example as Perbunan® or Europrene®. Flat gaskets made of NBR are particularly resistant to oil and fuel, which is why they are also called oil-resistant gaskets.
NBR materials available from Rehm Dichtungen Ehlers GmbH
We usually purchase our NBR from Semperit. On the data sheets of the Semperit qualities, the oil resistance can be read off from the indicated swelling.
Our stock programme starts with the 50-shore quality, which is suitable for low mechanical requirements and not for aromatic oils. The standard NBR qualities include, for example, the Semperit quality P9540 with a 65 Shore hardness, which is both oil and petrol resistant. The quality P9548, also from Semperit, with 80 Shore hardness is a rather rarely desired quality.
If you need an NBR grade for applications in gas pipes and for use as a gas meter seal, P518 is the most suitable.
As a high-quality pure NBR grade with the best resistance to oil and petrol, we stock P534. For applications with aromatic and aliphatic oils, we recommend P559. If you want to use NBR in the food sector, go for quality P627. This quality has been tested according to FDA and complies with BVR XXI, Cat. 2, as well as all current food regulations.
We also stock this material from the manufacturer Cooper Standard. Quality A-NT 68-00, also known as NBR super, is resistant to transformer oil in accordance with Siemens standard SN 53145-1 and is approved for use in this environment.
Semperit qualities
P518 NBR Gas 80 Shore
Technical data sheet:
Properties:
| Hardness [Shore A] | ISO 7619-1 | 80 +-5 |
| Density [g/cm³] | ISO 1183 | Approx. 1.35 |
| Tensile strength [N/mm²] | ISO 37-S2 | 10 |
| Elongation at break [%] | ISO 37-S2 | 150 |
Approvals and certifications:
- certified according to DIN EN 682
- (For seals in supply lines and components for gas and liquid hydrocarbons, type GB, working temperature -5 to +50 degrees Celsius)
- certified according to DIN EN 549
- (For gaskets in gas appliances and gas systems, hardness range H3 temperature class B1)
- Corresponds to WDK guideline 2201
- SVHC-free
P534 NBR 60 Shore
Technical data sheet:
Properties:
| Hardness [Shore A] | ISO 7619-1 | 60 +-5 |
| Density [g/cm³] | ISO 1183 | Approx. 1.19 |
| Tensile strength [N/mm²] | ISO 37-S2 | 11 |
| Elongation at break [%] | ISO 37-S2 | 400 |
Approvals and certifications:
- High quality nitrile with good mechanical properties
- Good oil resistance
- Good petrol resistance (alcohol-free petrols) up to 30% aromatic content
- Corresponds to WDK guideline 2201
- SVHC-free
P559 NBR 70 Shore
Technical data sheet:
Properties:
| Hardness [Shore A] | ISO 7619-1 | 70 +-5 |
| Density [g/cm³] | ISO 1183 | Approx. 1.49 |
| Tensile strength [N/mm²] | ISO 37-S2 | 10 |
| Elongation at break [%] | ISO 37-S2 | 330 |
Approvals and certifications:
- High quality nitrile with good mechanical properties
- Good oil resistance
- recommended for mineral oil-based oils up to 30% aromatic content
- good petrol resistance (alcohol-free petrol)
- Corresponds to WDK guideline 2201
- SVHC-free
P627 NBR light 60 Shore
Technical data sheet:
Properties:
| Hardness [Shore A] | ISO 7619-1 | 60 +-5 |
| Density [g/cm³] | ISO 1183 | Approx. 1.29 |
| Tensile strength [N/mm²] | ISO 37-S2 | 811 |
| Elongation at break [%] | ISO 37-S2 | 500 |
Approvals and certifications:
- Food quality
- FDA 21 Food and Drugs Part 177.2600
- PAH free - fully complies with GS Cat.3
- Corresponds to WDK guideline 2201
- SVHC-free
P9540 NBR/SBR 65 Shore
Technical data sheet:
Properties:
| Hardness [Shore A] | ISO 7619-1 | 65 +-5 |
| Density [g/cm³] | ISO 1183 | Approx. 1.45 |
| Tensile strength [N/mm²] | ISO 37-S2 | 7 |
| Elongation at break [%] | ISO 37-S2 | 250 |
Approvals and certifications:
- For medium mechanical requirements
- Good oil resistance
- petrol resistant (only non-alcoholic petrol)
- Corresponds to WDK guideline 2201
- SVHC-free
P9541 NBR/SBR 65 Shore PAH-free
Technical data sheet:
P9541 NBR/SBR 65 Shore PAH-free
Properties:
| Hardness [Shore A] | ISO 7619-1 | 65 +-5 |
| Density [g/cm³] | ISO 1183 | Approx. 1.45 |
| Tensile strength [N/mm²] | ISO 37-S2 | 7 |
| Elongation at break [%] | ISO 37-S2 | 250 |
Approvals and certifications:
- phthalate-free
- Good oil resistance
- petrol resistant (only non-alcoholic petrol)
- For medium mechanical requirements
- PAH free - fully complies with GS Cat.3
- Corresponds to WDK guideline 2201
- SVHC-free
P9548 NBR/SBR 80 Shore
Technical data sheet:
Properties:
| Hardness [Shore A] | ISO 7619-1 | 80 +-5 |
| Density [g/cm³] | ISO 1183 | Approx. 1.45 |
| Tensile strength [N/mm²] | ISO 37-S2 | 5 |
| Elongation at break [%] | ISO 37-S2 | 200 |
Approvals and certifications:
- Corresponds to WDK guideline 2201
- SVHC-free
P9639 NBR/SBR 50 Shore
Technical data sheet:
Properties:
| Hardness [Shore A] | ISO 7619-1 | 50 +-5 |
| Density [g/cm³] | ISO 1183 | Approx. 1.25 |
| Tensile strength [N/mm²] | ISO 37-S2 | 5 |
| Elongation at break [%] | ISO 37-S2 | 250 |
Approvals and certifications:
- Suitable for low mechanical requirements
- Corresponds to WDK guideline 2201
- SVHC-free
Import qualities
NBR/SBR 50 Shore
Technical data sheet:
Properties:
| Hardness [Shore A] | ISO 7619-1 | 50 +-10 |
| Density [g/cm³] | ISO 1183 | Approx. 1.4 |
| Tensile strength [N/mm²] | ISO 37-S2 | 4 |
| Elongation at break [%] | ISO 37-S2 | 250 |
NBR/SBR 65 Shore
Technical data sheet:
Properties:
| Hardness [Shore A] | ISO 7619-1 | 65 +-10 |
| Density [g/cm³] | ISO 1183 | Approx. 1.4 |
| Tensile strength [N/mm²] | ISO 37-S2 | 4 |
| Elongation at break [%] | ISO 37-S2 | 250 |
NBR/SBR 65 Shore with insert
Technical data sheet:
Properties:
| Hardness [Shore A] | ISO 7619-1 | 65 +-10 |
| Density [g/cm³] | ISO 1183 | Approx. 1.4 |
| Tensile strength [N/mm²] | ISO 37-S2 | 4 |
| Elongation at break [%] | ISO 37-S2 | 250 |
NBR/SBR 80 Shore
Technical data sheet:
Properties:
| Hardness [Shore A] | ISO 7619-1 | 80 +-10 |
| Density [g/cm³] | ISO 1183 | Approx. 1.5 |
| Tensile strength [N/mm²] | ISO 37-S2 | 4 |
| Elongation at break [%] | ISO 37-S2 | 200 |
NBR/SBR light 65 Shore
Technical data sheet:
Properties:
| Hardness [Shore A] | ISO 7619-1 | 65 +-10 |
| Density [g/cm³] | ISO 1183 | Approx. 1.5 |
| Tensile strength [N/mm²] | ISO 37-S2 | 5 |
| Elongation at break [%] | ISO 37-S2 | 300 |
CooperStandard
A-NT 68-00 NBR
Technical data sheet:
Properties:
| Hardness [Shore A] | ISO 7619-1 / 3s | 70 +-5 |
| Density [g/cm³] | DIN EN ISO 1183 / ISO 2781 | Approx. 1.41 |
| Tensile strength [N/mm²] | ISO 37 | 7 |
| Elongation at break [%] | ISO 37 | 400 |
Approvals and certifications:
- Resistant to transformer oil, biogas, biodiesel
- Complies with Siemens standard SN 53145-1
- PAH-free according to AfPS GS 2014 corresponds to Cat. 1
- PAH free
The properties of NBR as a sealing material
NBR consists of loosely cross-linked polymer molecules. The proportion of acrylonitrile is between 18 % and 50 %, depending on the intended use of the material. The specific proportion of this component has an influence on various properties of the elastomer. Thus the:
- Swelling resistance,
- Elasticity,
- Cold flexibility,
- Gas permeability
- and compression set.
If the acrylonitrile content is rather low, the resistance to oils and fuels is reduced. On the other hand, the material is much more flexible at low temperatures. A high acrylonitrile content worsens the mechanical behaviour at low temperatures, but improves the resistance to oils and fuels. For this reason, it can be summarised that the cold flexibility is opposite to the oil resistance. In general, the temperature resistance of NBR is lower than that of EPDM.
NBR in standard material quality has a medium acrylonitrile content to cover the widest possible range of applications. As a standard material, the material shows good mechanical values, including good resistance to lubricating oils and greases based on mineral oil as well as to water up to about +80° C.
Due to its excellent properties against oils, greases and fuels, the sealing material NBR is also used in combination with aramid fibres in fibrous materials. The proportion of NBR in the composition of the respective fibre material is approx. 10% to 25%. The use of NBR influences the properties of the flat gasket in terms of media and temperature resistance, tightness as well as elasticity and setting behaviour. Examples of fibre materials bonded with NBR are the C-4400 from the manufacturer Klingersil, the AFM 34 from the manufacturer Reinz as well as Novapress Universal from Frenzelit.
The advantages and material properties of NBR at a glance
In general, NBR is impermeable to gas and air, which is why the material is well suited for use in industry as well as in gas supply.
The mechanical specifics of NBR include high abrasion resistance, good tensile and tear strength and low compression set.
In terms of thermal properties, the elastomer is temperature-resistant between a maximum of -30 °C and +120° C - depending on the specific composition and the proportion of acrylonitrile.
The chemical properties of NBR include its resistance to aliphatic hydrocarbons such as propane or butane. In addition, nitrile rubber has good resistance to fuels and mineral oils, depending on the proportion of the acrylonitrile component. Furthermore, NBR is considered resistant to alcohols, vegetable and animal fats and oils. Silicone oils and greases as well as hot water up to +80° C do not affect this material.
Since gaskets or other components made of this sealing material hardly become electrostatically charged, the material is well suited for use in tank and petrol hoses.
The disadvantages of NBR seals
In addition to the above-mentioned advantages and properties of this material, it is also necessary to name the disadvantages and limitations of NBR seals.
A disadvantage of the material is the mediocre resistance to ageing, which is based on the resistance to UV radiation and ozone. If, due to the mechanical, thermal and chemical properties, the use of the material is nevertheless considered with regard to one of the two imperfections, increased maintenance requirements should be expected. In addition, flat gaskets made of NBR have a medium to poor resistance to some polar media, such as amines, ketones or strong acids and alkalis. Finally, the material is not compatible with aromatic hydrocarbons, such as benzene.
A further restriction of NBR seals concerns the temperature application range of the material. Depending on the material composition, this lies between -20° C and max. +110° C. If the gasket is used outside this temperature range, there is a risk that the NBR gasket will be damaged and lose its sealing properties.
For applications outside the limits of the NBR material, alternative gasket materials should be used to guarantee optimum performance and longevity of the flat or flange gasket.
Distinctions between NBR seals and other sealing materials
With regard to chemical resistance and resistance to oils and greases, gaskets made of NBR are preferable to gaskets made of CR. Especially if the flange or flat gasket comes into contact with fuels in your application.
Compared to the sealing material EPDM, NBR has a poorer resistance to ageing and ozone. EPDM seals are also more temperature-resistant. The advantages of nitrile rubber over EPDM lie primarily in its resistance to petrol and oil.
The heat resistance of flat gaskets made of NBR is significantly higher than that of NR or SBR, but the ozone resistance is much worse compared to NR. The strength of the gasket material compared to NR/SBR is considered lower.
If the use of flat gaskets made of nitrile rubber is ruled out in view of high operating temperatures and complex chemical requirements, flat gaskets made of FKM can be considered as an alternative.
NBR resistances at a glance
| Material designation | Ozone resistance | Weather resistance | Oil resistance | Petrol resistance (alcohol-free petrols only) | Resistance to acids & strong bases |
| Semperit P 518 | conditionally stable | not durable | Well resistant | constant | constant |
| Semperit P 534 | conditionally stable | conditionally stable | Well resistant | Well resistant | constant |
| Semperit P 559 | not durable | not durable | Well resistant | Well resistant | conditionally resistant / resistant |
| Semperit P 627 | not durable | not durable | constant | not durable | constant |
| Semperit P 9540 | not durable | not durable | Well resistant | constant | conditionally stable |
| Semperit P 9541 | not durable | not durable | Well resistant | constant | conditionally stable |
| Semperit P 9548 | not durable | not durable | constant | conditionally stable | conditionally stable |
| Semperit P 9639 | not durable | not durable | constant | not durable | conditionally stable |
| Cooper Standard A-NT 68-00 | not durable | not durable | constant | constant | conditionally stable |
The way to your flat gasket made of NBR
The NBR qualities presented, which we store as standard, are first subjected to a quality control in the incoming goods department. Following approval, the sealing material is stored in the form of rolls and sheets.
NBR belongs to the group of sealing materials that can be processed in all our production processes. For this reason, the selection of the most suitable production process for your flat gaskets made of this material depends on the number of pieces, the corresponding contour and the thickness of the respective material. The unprocessed roll or sheet material is then processed into your individual NBR flat gasket. In addition, it is possible to provide the roll or sheet material with a self-adhesive finish in advance and then process these into your self-adhesive flat gaskets with the help of our production processes. As with all our other materials, self-adhesive NBR gaskets are used exclusively as an assembly aid without changing the material properties of the material. In addition to the production of flange and flat gaskets, we also offer unprocessed rolls or sheets as well as metre goods cut to size for further processing. Here, too, we offer the option of applying a self-adhesive film to the material.
After completion of the production steps and a renewed quality control, the flat or flange gaskets are packed and shipped to you.
Areas of application for NBR seals
The material NBR is frequently used to produce rubber seals - especially flat seals - which are used in a wide variety of industries. The synthetic rubber is available to us in rolls and sheets. We will be happy to cut these to size for you.
Applications include seals for gas supply and oil production. Furthermore, flat gaskets made of this material can be used for internal coatings for containers or pipes against corrosion. Thanks to the good oil and fuel resistance of nitrile rubber, NBR seals are suitable for hydraulic and pneumatic applications. They are also suitable for use in mechanical engineering, among other things because of their oil and fuel resistance. The advantages of the material also make it possible to use the seals in engines, transmissions and fuel systems. Finally, we are aware of the use of NBR seals in rollers for the printing, paper and textile industries.
We will be happy to answer whether the elastomer is also suitable for your purposes. Please contact our customer service, who will be happy to provide you with comprehensive advice.