HSN/HNBR O-Rings

HNBR O-Ring Material Description

Hydrogenated Nitrile (HNBR) o-rings, also known as Highly Saturated Nitrile (HSN), are made of a synthetic polymer that is obtained by saturating the double bonds in nitrile’s butadiene segments with hydrogen. This special hydrogenation process reduces many double bonds in main chains of NBR polymers. This process results in the superior heat, ozone, chemical resistance, and mechanical characteristics of HNBR over standard Nitrile. HNBR o-rings are available in 70, 80, and 90 durometers.

HNBR o-rings are preferable for use with petroleum-based oils and fuels, aliphatic hydrocarbons, vegetable oils, silicone oils and greases, ethylene glycol, water, and steam (up to 300ºF), and diluted acids, bases, and salt solutions. HNBR o-rings are not preferable for use with chlorinated hydrocarbons, ketones, ethers, esters, and strong acids.

Acrylonitrile Content

Just like NBR, there are three different levels of Acrylonitrile (ACN) content in different HNBR polymers. The ACN content can be varied from 17% to 49%. Lower ACN content gives better low-temperature properties but lesser resistance to fuels and polar lubricants. Higher ACN content gives inferior low-temperature properties but improves fuels and polar lubricant resistance. Standard HNBRs typically have 36% ACN content.

Cure System: Peroxide-Cured

HNBR o-rings are usually peroxide-cured but can also be sulfur-cured to improve flexible properties in dynamic systems. However, sulfur-curing will reduce the heat resistance and cause an inferior compression set.

HNBR O-Ring Compounds

Compounds	Durometer	Color	Temp Range (F)	Data Sheet	Description
HNBR70	70	Black	-40 to +302		Heat/Chemical resistance
HNBR80	80	Black	-40 to +302		Heat/Chemical resistance
HNBR90	90	Black	-40 to +302		Heat/Chemical resistance
H90105	90	Black	-67 to +302		Rapid gas decompression resistance, Low temperature resistance
H90104	90	Black	-13 to +302		Rapid gas decompression resistance
HSN70	70	Green	-40 to +303		Heat/Chemical resistance
HSN80	80	Green	-40 to +303		Heat/Chemical resistance
HSN90	90	Green	-40 to +303		Heat/Chemical resistance