HNBR O-ring

What is HNBR O-ring?

HNBR O-ring also known as Hydrogenated Nitrile o-ring which is made of high quality HNBR rubber compound. HNBR is a synthetic polymer that is obtained by saturating the double bonds in nitrile=s butadiene segments with hydrogen. Standard HNBR typically has 36% ACN content which improves fuels and polar lubricants resistance. HNBR O-ring has the superior heat, ozone, chemical resistance and mechanical characteristics over standard Nitrile o-ring. HNBR o-ring is available in 60 durometer, 70 durometer, 80 durometer, and 90 durometer.

HNBR o-ring is 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-ring is not preferable for use with chlorinated hydrocarbons, ketones, ethers, esters, and strong acids.

Acrylonitrile Content of HNBR

Just like NBR, there are 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 lubricants resistance. Standard HNBRs typically have 36% ACN content.

Cure System, Peroxide-Cured HNBR o-ring:

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

Mechanical Properties of HNBR O-ring

HNBR o-ring has good compression set resistance, excellent heat stability, good shorter term resilience and good permeation resistance.

Advantages of HNBR O-ring

HNBR O-ring is compatible with freon R-134a and compressor lubricant oil. It has extended temperature capabilities, enhanced chemical compatibility with new automotive fuels. It also has excellent resistance to compression set and abrasion, excellent resistance to many petroleum oils greases, H2S, hydraulic fluids, alcohol, ambient water, silicone greases, Di-ester base lubricants, CO2 and ethylene-glycol based fluids.

Limitations:

Ozone, direct sunlight, UV, weathering, aromatic fuels, glycol-based brake fluids, polar solvents, non-flammable hydraulic fluids (HFD), aromatic and chlorinated hydrocarbons, ketones, esters, and aldehydes.

Applications of HNBR O-ring

HNBR O-ring is recommended for petroleum-based oils and fuels, Aliphatic hydrocarbons, Vegetable oils, Silicone oils and greases, Ethylene glycol, Dilute acids, bases, and salt solutions to moderate temperatures, water, and steam to 150°C.

What's The Difference Between HNBR and NBR O-Rings?

In comparison with NBR O-ring, HNBR O-ring has better abrasion resistance, tear resistance, high-temperature properties and resistance to chemical attacks.

Hydrogenated Nitrile (HNBR) Material Temperature Range:

Heat Resistance: Up to approximately continues working temperature 300°F (150°C)
Cold Flexibility: Down to approximately -55°F (-48°C).

HNBR O-ring Properties

HNBR Compound	Hardness Shore A	Rubber Color	Temp range °C	Elongation at break %	Tensile Strength Mpa
HN 400	70	Green	-40 to 155	360	11.35
HN 401	70	Black	-35 to 155	220	13
HN 402	80	Black	-40 to 155	310	15
HN 403	60	Green	-40 to 155	370	10.2

More HNBR compounds please contact us.

HNBR Chemical Compatibility

Rubber Materials	Excellent good	Quite Good	Very Bad
Aliphatic Hydrocarbons	1
Automatic transmission fluid	1
Automotive refrigerants	1
Brake fluids non-petroleum		2
Chlorinated hydrocarbons			3
Dilute Acids	1
Hydraulic Fluids HFA, HFC, HFB	1
Polar solvents (Keytones)			3
Salt solutions		2
Silicone oils	1
Strong acids			3
Vegetable animal fats / oils	1
Water Steam up to 300 ºF	1

1 means excellent good, 2 means quite good and 3 means very bad

Testing