Hydrogenated Nitrile Butadiene Rubber (HNBR) – Properties and Applications

Updated by Reginald Davey 07/09/23

Hydrogenated nitrile butadiene rubber (HNBR) is a widely used material in several industries due to its excellent physical properties and chemical resistance. This article will discuss the properties and applications of HNBR.

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Overview

HNBR is produced by hydrating nitrile rubber. An elastomer, HNBR’s properties are determined by its acrylonitrile content. Its resistance to abrasion, alongside its excellent physical properties, makes HNBR a widely used material in the oil, transport, gas, and industrial sectors.

Properties

HNBR is widely known for its physical strength and properties retention after long-term exposure to heat, oil, and chemicals. Depending on filler selection and loading, HNBR compounds typically have tensile strengths of 20 - 31 MPa when measured at 23°C.

Compounding techniques can be used to produce HNBR, which performs well over a broad temperature range of -40° to 165°C with minimal degradation over extended time periods.

For low-temperature performance, low ACN grades should be used; high-temperature performance can be obtained by using highly saturated HNBR grades with white fillers.

As a group, HNBR elastomers have excellent resistance to common automotive fluids (e.g., engine oil, coolant, fuel, etc.) and many industrial chemicals. HNBR has good resistance to crude oil, even in the presence of chemicals such as alkaline corrosion inhibitors, hydrogen sulfide, and amines.

Other beneficial HNBR properties include low vibration/noise transmission, low permeability to gases and volatile compounds, good ozone resistance, and low compression set at high temperatures. Like NBR, fluid, and chemical resistance improves as the ACN content is increased.

Applications

The unique properties attributed to HNBR have resulted in the wide adoption of HNBR in automotive, industrial, and assorted performance-demanding applications. On a volume basis, the automotive market is the largest consumer, using this material  for a host of dynamic and static HNBR seals, hoses, and belts.

HNBR seals have also been widely employed in the petrochemical industry for oil field exploration and processing. Additionally, HNBR rolls are used in steel and paper mills.

Common uses of HNBR include:

HNBR is not suitable for applications where it can come into contact with ketones, esters, or chlorinated hydrocarbons due to its similar material compatibility to nitrile rubber.

In Summary

Hydrogenated acrylonitrile butadiene rubber is a commonly employed material in several industries, known for its superior physical properties and excellent resistance to a wide range of industrial chemicals and fuel types and abrasion resistance. HNBR seals, gromits, and hoses are common applications.

Whilst it is suitable for a wide range of industrial uses, other materials such as FKM and FFKM are recommended in applications where parts may come into contact with environments containing chemicals such as chlorinated hydrocarbons and ketones.

References and Further Reading 

Southbourne Rubber (website) Hydrogenated Acrylonitrile Butadiene Rubber (HNBR) [online] southbournerubber.co.uk. Available at:

https://www.southbournerubber.co.uk/Hydrogenated-Nitrile-Rubber-HNBR/

TRP Polymer Solutions (website) HNBR material data sheet [online] trp.co.uk. Available at: