Nitrile Rubber, also known as Buna-N and NBR is a copolymer of Butadiene and Acrylonitrile and is the most widely used elastomer at temperatures between -40F and +250F. The popularity of nitrile is explained by its low cost, good performance in oils, chemicals and wide availability.
Nitrile is widely used in the automotive, aeronautical, and nuclear industries offering excellent resilience and chemical resistance that makes this elastomer ideal for products ranging from exam gloves to critical automotive seals.
Despite the wide suitability of Nitrile in many applications, there are many environments that can reach temperatures below -40F. The problem with using an elastomer below its operating temperature is excessive shrinkage of the rubber. A rubber elastomer can shrink up to 10 times more than a mating metal or plastic surface. Should the O-Ring or rubber seal shrink excessively, there is a high probability that a leak path could develop. Elastomers used in dynamic applications are even more sensitive to the effect of low temperature and usually cannot be used at same low temperatures that a static seal would still perform.
What If My Nitrile Application Needs to Perform at Below -40F?
Rubber manufacturers with strong compounding skills can modify the Nitrile elastomers for lower temperature applications.
Nitrile formulations with smaller amounts of Acrylonitrile can perform at low temperatures with the drawback of slightly inferior performance in fuels and oils. Temperatures down to -65F can be accommodated with Acrylonitrile modification.
Rubber seal manufacturers that have strong compound development technology can work carefully with your Engineering team to incorporate the right level of low temperature performance and fuel/oil resistance to perform best in your applications.
Utilization of the right low temperature Nitrile compound can reduce field failures and allow your company to focus on new product design and launch instead of lengthy failure analysis.
Article Authored by:
Craig Webb – Director of Business Development, O-Rings.com by Boyd Corporation
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