NBR Rubber seal

NBR, whose full name is Nitrile Butadiene Rubber, is a synthetic rubber produced by the emulsion polymerization of butadiene and acrylonitrile. Since its industrial production began in the 1930s, it has become an indispensable key material in fields such as industrial sealing and protection due to its excellent oil resistance and adaptability. Especially in scenarios involving contact with oil-based media, its performance advantages far surpass those of natural rubber and most other general-purpose synthetic rubbers.

The performance characteristics of NBR revolve around the core of "oil resistance" while possessing certain mechanical properties and environmental adaptability, which can be specifically summarized into the following three points:

This is the most iconic property of NBR. The acrylonitrile groups (-CN) in its molecular structure have strong polarity, which can form stable interactions with non-polar molecules in oils (such as mineral oil, vegetable oil, and lubricating oil), effectively preventing oil penetration. Compared with natural rubber (which has a low oil resistance level and is easily swollen by oils), the volume change rate of NBR in oil environments is usually less than 15%, and it can maintain good elasticity and sealing performance. At the same time, it also has a certain degree of tolerance to some organic solvents such as alcohols and ketones (the specific tolerance range is adjusted according to the acrylonitrile content).

The tensile strength of NBR can reach 15-25MPa, and its elongation at break is approximately 300%-500%. Although slightly inferior to natural rubber, it is sufficient to meet the mechanical requirements of scenarios such as industrial sealing and hoses. Meanwhile, its surface hardness can be adjusted within the range of 50-90 Shore A through formula modification (e.g., adding carbon black, vulcanizing agents). Combined with its excellent wear resistance, it can reduce wear and tear during long-term use and extend the service life of products.

The applicable temperature range of ordinary NBR is -30℃ to 120℃, which can be expanded to -40℃ to 150℃ through modification (e.g., adding anti-aging agents, blending with other rubbers), enabling it to adapt to temperature fluctuations in most industrial environments. In addition, although its ozone resistance and weather resistance are weaker than those of chloroprene rubber and ethylene-propylene rubber, in closed or semi-closed scenarios such as sealed cavities and hydraulic systems, its aging rate is slow and its stability is good.