NBR

NBR is a synthetic rubber based on acrylonitrile and butadiene. Due to its acrylonitrile content, NBR has a high resistance to oils and fuels and is therefore one of the most important materials for oil-resistant seals in mechanical and plant engineering. Depending on the acrylonitrile content, oil resistance, cold flexibility and other properties can be specifically adjusted.

Properties of NBR

Typical properties of NBR elastomers are:

• Good mechanical properties (tensile strength, tear resistance, abrasion resistance)
• low compression set compared to many other elastomers
• good low-temperature behaviour depending on the mixture, typically down to approx. -30 °C, special types down to approx. -40 °C to -50 °C
• Very good resistance to hydraulicölen, mineralölen, lubricants and many mineral oil products
• Good resistance to oil-in-water emulsions (HFA), water-in-oil emulsions (HFB) and polymer solutions in water (HFC fluids)
• Good resistance to animal and vegetable oils and many fats
• Ozone and weather resistance are considered to be rather poor – unprotected NBR components degrade relatively quickly when used outdoors

The typical temperature range for NBR seals is between -30 °C and +100 °C, depending on the compound. Special grades allow higher temperatures of up to approx. +120 °C for short periods or improved cold flexibility, always depending on the mixture, medium and duration of exposure.

Media resistance of NBR

NBR is particularly suitable for:

• Mineral oil-based hydraulic oils
• Gear oils, lubricating oils, oil/water emulsions
• Fuels (petrol, diesel – depending on formulation and additives)
• Many cooling lubricants and process oils
• Animal and vegetable oils/fats

However, NBR is less suitable for:

• Prolonged contact with ozone, weathering and direct UV radiation
• highly polar media (e.g. glycol-based brake fluids – EPDM is generally used here)
• many aromatic and chlorinated hydrocarbons

Typical applications of NBR

Due to its property profile, NBR is a standard material for oil- and fuel-resistant seals:

• NBR O-rings and moulded seals in hydraulic and pneumatic systems
• Shaft seals and shaft sealing rings (radial shaft seals) in gearboxes, pumps and aggregates
• Scrapers, sleeves and compensators in mechanical and plant engineering
• NBR moulded parts and NBR profiles in lubrication and fuel systems
• Diaphragms, baffles and damping elements for general industrial applications
• NBR compounds with approvals (e.g. KTW, DVGW, etc.) for specific media and areas of application

NBR is therefore suitable for use wherever mineral oils, lubricants, fuels or hydraulic fluids play a central role and no significant ozone or weathering exposure is to be expected. Alternative materials such as HNBR, FKM or EPDM are often used for high-end applications with higher temperatures, better weather resistance or more aggressive media.

Disposal

According to the “Regulation on the European Waste Catalogue (AVV)”, the waste product from NBR can be classified according to Chapter 7 “Wastes from organic chemical processes” and the waste code 07 02 99. This waste code stands for waste classified as non-hazardous.

They can therefore be disposed of in normal household quantities with normal household waste. Please use the container provided by your public waste disposal authority for residual waste as the appropriate disposal container.

Synonyms: Perbunan®