Nitrile rubber (NBR, BUNA-N)

Butadiene-acrylonitrile copolymer is also known as nitrile rubber (NBR). The acrylonitrile content in the nitrile rubber molecule is variable (18% - 50%) and affects the properties of the finished material.

The higher the acrylonitrile content, the better the resistance to lubricating oils and fuel oils, but its low temperature elasticity and compression set rate become worse. The lower the acrylonitrile content, the better the low temperature resistance, but at the same time it also sacrifices the oil resistance at high temperatures. Standard NBR usually has an ACN content of 34%. Compared with other elastomers, nitrile rubber has good mechanical properties and high wear resistance.

Nitrile rubber is not very resistant to weather and ozone. Some special formulas can improve this defect, or use NBR/PVC blends, which will have excellent weather resistance, ozone resistance, and fuel resistance.

Vulcanization system

Sulfur bridging and peroxide bridging

Standard nitrile rubber is usually sulfur-bridged. Sulfur-bridged compounds have better low-temperature properties, but poorer performance at high temperatures. Peroxide-bridged nitrile rubber has better heat resistance and better compression set, but is more expensive and has poorer processability.

Temperature range

General grade: -40 ~ 100℃

Low temperature grade: -55 ~ 100℃ (TR10: -49.2℃)

High temperature grade: -30 ~ 125℃ (air)

Hardness

Shaw A30 degrees to 93 degrees

Color

Black, brown, green, white, red, yellow, blue, orange, grey, or customer-specified colors

Application

NBR formulations have excellent resistance to friction, non-polar oils and solvents, water and penetration (higher acrylonitrile content is preferred).

NBR can also be used in dilute acids, alkalis and salt solvents at low temperatures.

NBR is not suitable for aromatic hydrocarbons, chlorinated hydrocarbons and polar solvents.

NBR is usually internally lubricated to improve installation convenience or reduce friction in motion.

For contact with food or beverages, NBR can be formulated with "white list" ingredients specified in FDA 21.CFR 177.2600.

For drinking water applications, NBR can apply for National Sanitation Foundation (NSF) approval.

NBR can be submitted for approval by Underwriters Laboratories (UL) for use in applications specified by UL157.

NBR can be combined with polyvinyl chloride (PVC) to produce NBR-PVC blends that are resistant to fuel, ozone and weather.