Nitrile Butadiene Rubber - NBR
Nitrile rubber, also known as Buna-N, Perbunan, or NBR, is a synthetic rubber copolymer of acrylonitrile (ACN) and butadiene. Trade names include Nipol, Krynac and Europrene. Nitrile butadiene rubber (NBR) is a family of unsaturated copolymers of 2-propenenitrile and various butadiene monomers (1,2-butadiene and 1,3-butadiene).
Physical properties of Nitrile rubber are – It belongs to the family of unsaturated copolymers of acrylonitrile and butadiene. The physical and chemical properties of this rubber vary depending on the polymers composition of acrylonitrile. Different grades are available for this rubber. The higher the acrylonitrile content within the polymer, the higher the oil resistance. It is generally resistant to fuel and other chemicals. It can withstand a range of temperatures. It has inferior strength and flexibility, compared to natural rubber. This rubber is also resistant to aliphatic hydrocarbons. It is less resistant to ozone, aromatic hydrocarbons, ketones, esters and aldehydes. It has high resilience and high wear resistance but only moderate strength. It has limited weathering resistance. It can generally be used down to about -30 degree celsius, but special grades can also operate at lower temperatures.
NBR’s ability to withstand a range of temperatures from -40 °C to +108 °C makes it an ideal material for automotive applications. Nitrile rubber is more resistant than natural rubber to oils and acids, but has less strength and flexibility. Nitrile rubber is generally resistant to aliphatic hydrocarbons. Nitrile, like natural rubber, can be attacked by ozone, aromatic hydrocarbons, ketones, esters and aldehydes. Nitrile is the most widely used elastomer in the seal industry. The popularity of nitrile is due to its excellent resistance to petroleum products and its ability to be compounded for service over a temperature range of -22°F to 212°F.
Nitrile is a copolymer of butadiene and acrylonitrile. Variation in proportions of these polymers is possible to accommodate specific requirements. An increase in acrylonitrile content increases resistance to heat plus petroleum base oils and fuels but decreases low temperature flexibility. Military AN and MS O ring specifications require nitrile compounds with low acrylonitrile content to insure low temperature performance.
Nitrile provides excellent compression set, tear, and abrasion resistance. The major limiting properties of nitrile are its poor ozone and weather resistance and moderate heat resistance, but in many applications these are not limiting factors.
Leading producers are Omnova Solutions, Industrias Eliokem S.A.S., Industrias Negromex S.A., Negromex S.A., JSR Corporation, Korea Kumho Petrochemical Co. Ltd., Lanxess AG, LG Chem Ltd., Nantex Industry Company Ltd., Nitriflex, PetroChina Company Limited /CNPC, Polimeri Europa SpA, Sibur Holding JSC Synthos SA, and Zeon Corporation. Eliokem is the only Indian Producer of NBR.
Consumption of NBR in automobile parts is poised to grow in the upcoming years. Demand is expected to grow especially in the developing countries as a result of auto manufacturers steadily shedding full line production processes and stepping up outsourcing to low cost countries in attempts to free up investment capital.
Global Nitrile Rubber capacity is expected to be around 1.5 MMT in 2016 while the capacity in India is 20 KTA at present.
Global OEMs and Tier I auto parts suppliers are increasingly adopting outsourcing of auto parts and accessories to effectively tackle escalating production costs and plummeting sales volume. Growing outsourcing trend by the OEMs and Tier I suppliers over the past couple of years has been accelerating auto parts exports from the developing countries.
In the medical industry, NBR is increasingly becoming popular as the preferred choice in the manufacture of medical gloves, since nitrile gloves are puncture-resistant in comparison to gloves made from natural rubber.
Primary Uses include - O-rings, rubber seals and custom molded rubber components for: Oil resistant applications, Low temperature applications, Fuel systems, automotive, marine, and aircraft, General Industrial Use, Hydraulic actuator seals, Hydraulic pump seals, Water pump seal, Carburetor seals, Transmission seals, Automotive fuel system seals. It is used in the roller industry, as it has a high resistance against Paraffinic Hydrocarbon based inks. Blue rubber medical gloves are also made from it, Shoes, Floor mats. It is used in the automotive and aeronautical industry to make fuel and oil handling hoses, seals, and grommets. It is used in the nuclear industry to make protective gloves. Its resilience makes NBR a useful material for disposable lab, cleaning, and examination gloves.