NBR (Nitrile)

What NBR is

Nitrile butadiene rubber, also sold as NBR, Buna-N, nitrile rubber and acrylonitrile butadiene rubber, is a synthetic copolymer of acrylonitrile and butadiene.

Its behaviour tracks the acrylonitrile content directly: the more nitrile in the polymer, the better the oil resistance and the worse the flexibility and low temperature performance. That single dial is how NBR compounds are specified.

Where it is used

• Automotive: fuel and oil hoses, seals, grommets and self sealing fuel tanks, applications where ordinary rubbers will not survive.
• Nuclear: protective gloves.
• Aeronautical: its working range of -40 C to 108 C suits aerospace use.
• General: moulded goods, footwear, adhesives, sealants, sponges, expanded foams and floor mats.

NBR against natural rubber

• Nitrile resists oils and acids far better than natural rubber, and has superior strength.
• It is more puncture resistant, and resists chemicals and ozone better than natural rubber does.
• It is less likely to cause an allergic reaction, which matters in glove applications.
• Buna-N is generally resistant to aliphatic hydrocarbons. It is attacked by ozone, ketones, esters and aldehydes.

Advantages and disadvantages

Advantages: oil resistance, water resistance, good sealing performance, good abrasion resistance.

Disadvantages: poor low temperature resistance, poor ozone resistance, poor insulation, low elasticity.

Compound grades