Nitrile butadiene rubber (NBR) is a family of unsaturated copolymers of 2-propenenitrile and various butadiene monomers (1,2-butadiene and 1,3-butadiene). Although its physical and chemical properties vary depending on the polymer’s composition of nitrile (the more nitrile within the polymer, the higher the resistance to oils but the lower the flexibility of the material), this form of synthetic rubber is generally resistant to oil, fuel, and other chemicals. Its resilience makes NBR a useful material for disposable lab, cleaning, and examination gloves. It is used in the automotive industry to make fuel and oil handling hoses, seals, and grommets. NBR’s ability to withstand a range of temperatures from −40°C to +120°C makes it an ideal material for extreme automotive applications. Nitrile butadiene is also used to create moulded goods, footwear, adhesives, sealants, sponge,expanded foams, and floor mats. Nitrile rubber is more resistant than natural rubber to oils and acids, but has inferior strength and flexibility. Nitrile gloves are nonetheless three times more puncture-resistant than rubber gloves. Nitrile rubber is generally resistant to aliphatic hydrocarbons. Nitrile, like natural rubber, can be attacked by ozone, aromatic hydrocarbons, ketones, esters and aldehydes.
Monomers are usually permitted to react for 5 to 12 hours. Polymerization is allowed to proceed to ~70% conversion before a “shortstop” agent (such as dimethyldithioarbamate and diethyl hydroxylamine) is added to react with the remaining free radicals. Once the resultant latex has “shortstopped”, the unreacted monomers are removed through a steam in a slurry stripper. Recovery of unreacted monomers is close to 100%. After monomer recovery, latex is sent through a series of filters to remove unwanted solids and then sent to the blending tanks where it is stabilized with an antioxidant. The yielded polymer latex is coagulated using calcium chloride, aluminium sulfate, and other coagulating agents in an aluminium tank. The coagulated substance is then washed and dried into crumb rubber.
The process for the production of cold NBR is very similar to that of hot NBR. Polymerization tanks are heated to 5 °C–15 °C instead of 30 °C–40 °C. Under lower temperature conditions, less branching will form on polymers (the amount of branching distinguished cold NBR from hot NBR).
The applications of nitrile rubber include automotive transmission belts, hoses, oil seals, V belts, synthetic leather, printer's roller, cable jacketing. The NBR latex can also be used to prepare adhesives, impegnation of paper and binder of pigments
WIPO ASSIGNS PATENT TO ZEON FOR "NITRILE RUBBER COMPOSITION, CROSSLINKED NITRILE RUBBER COMPOSITION, CROSSLINKED RUBBER MATERIAL, AND METHOD FOR PRODUCING NITRILE RUBBER COMPOSITION" (JAPANESE INVENTORS)
Feb 16, 2011; GENEVA, Feb. 16 -- Publication No. WO/2011/016479 was published on Feb. 10. Title of the invention: "NITRILE RUBBER COMPOSITION,...