Hydrogenated Nitrile
(HNBR)

What is HNBR?
Hydrogenated Nitrile (HNBR), sometimes referred to as “saturated nitrile,” is a synthetic elastomer derived from standard nitrile (NBR) by hydrogenating (adding hydrogen to) the polymer’s hydrocarbon chains. This chemical modification saturates much of the double bonds in the butadiene segments, resulting in a more stable molecular backbone — and substantially improved performance characteristics over standard NBR.

The extent of hydrogenation can vary (fully or partially saturated grades), which in turn allows tailoring of material properties — enabling a range of HNBR compounds optimized for specific temperature, chemical or mechanical demands.

Why Use HNBR? Key Advantages

• Superior chemical and oil resistance — HNBR maintains excellent resistance to a wide variety of aggressive media, including mineral oils, fuels (including biodiesel and oxidized fuels), lubricants (even those with detergents, anti-wear or antioxidant additives), animal and vegetable fats, mineral and vegetable oils, and many hydraulic fluids. It also tolerates sour gas, amine/oil mixtures, and dilute acids or bases in many cases.
• Enhanced thermal stability & aging resistance — Compared with standard nitrile, HNBR exhibits much better resistance to heat, oxidation and ozone. This translates to long-term stability even under high-temperature or harsh environmental conditions.
• High mechanical strength & durability — HNBR typically offers high tensile strength, good elongation, strong abrasion and tear resistance, low compression set (i.e. it returns well to its original shape after being compressed), and strong dynamic performance under load.
• Wide operating temperature range — Many HNBR compounds perform reliably over a broad temperature range, typically from around –40 °C up to +150 °C (with some peak/short-term tolerances higher).
• Excellent weather, ozone, steam and environmental resistance — The saturated backbone makes HNBR far less prone to degradation from ozone, oxygen, atmospheric exposure, and many outdoor or industrial conditions. Some grades also tolerate steam or hot water, increasing versatility.

Because of these attributes, HNBR often fills the gap between standard NBR and more expensive high-performance elastomers (e.g. fluoroelastomers), offering a cost-effective yet robust sealing solution for demanding applications.

Common Applications & Typical Use Cases

HNBR’s durability, chemical resistance, and thermal stability make it a go-to elastomer for a wide variety of uses, across industries. Typical applications include:

• Seals, gaskets, O-rings, back-up rings, and static/dynamic seals — especially in environments with oil, fuels, chemical exposure, or high pressure.
• Automotive industry: fuel handling systems, hydraulic and fuel seals, engine & transmission components — where oil and chemical exposure plus heat are common.
• Oil & gas industry: oil-well seals, gaskets and packings that must resist sour gas, crude oil, sludge, and additives.
• General industrial sealing: hydraulic systems, chemical processing, steam systems, machinery, and wherever abrasion resistance and long-term chemical/thermal stability are required.
• Applications with dynamic or cyclic loads: belts, vibration-damping components, grommets, and other elastomeric parts that require toughness under mechanical stress.

In short: HNBR is one of the most versatile elastomeric materials for applications where both chemical/oil resistance and mechanical/thermal demands are high.

Some HNBR grades tolerate steam and hot water, subject to compound selection.

Typical Material Specifications & Grades

While actual specifications vary by supplier and compound grade, the following are representative properties and standard offerings:

• ASTM Designation: HNBR (also sometimes HSN) under standard classification systems.
• Hardness (Shore A): Commonly 50–90 (some sources list a broader range, e.g. 30–95 depending on formulation).
• Typical Operating Temperature Range: from around –40 °C up to +150 °C (continuous service), with some peak or short-term tolerances slightly higher.
• Mechanical Properties: High tensile strength (often up to ~30 MPa for well-compounded grades), good elongation and tear strength, low compression set, strong abrasion resistance and longevity under dynamic conditions.
• Colour Options: Many standard HNBR compounds come in black, green — but red, yellow or other colours may be available depending on the supplier.

Important Note: Because HNBR properties depend heavily on the exact compound, additives, and curing method used (e.g. sulfur vs peroxide cure, saturation degree, fillers), the data above should be considered a general guideline. End-users should always verify performance with actual material certificates (especially for critical applications).

Selecting the Right HNBR Grade for Your Application

Because HNBR compounds vary significantly depending on degree of hydrogenation, filler content, curing system, acrylonitrile content, and other formulation choices — selecting the right grade for a given use is essential. Here are some guidelines:

• For high-temperature, oil or fuel-exposed environments (e.g. automotive, hydraulic systems, oil & gas): choose a fully hydrogenated, high-saturation HNBR grade with high hardness, high abrasion and oil resistance.
• For dynamic / high-wear applications (seals subject to motion, vibration, cyclic loading): prioritize low compression set, high tear/abrasion resistance, good resilience, and ensure compatibility with the expected media (oils, fuels, gases).
• For low-temperature applications, or where flexibility in the cold is important: consider partially hydrogenated grades or formulations with lower crystallization tendency — but check the supplier’s low-temperature data.
• Always verify chemical compatibility — particularly when dealing with polar solvents, aggressive chemicals, or unusual media (e.g. aromatic solvents, chlorinated compounds). If compatibility is uncertain, perform testing or consider alternative elastomers.
• Request certificates of compliance / material data sheets from your supplier to confirm hardness, temperature range, tensile strength, elongation, compression set, media resistance, and any approvals (e.g. food contact, rapid gas decompression, environmental).

Summary

Hydrogenated Nitrile (HNBR) is a highly versatile elastomer that offers a compelling blend of oil/chemical resistance, thermal and aging stability, mechanical strength, and abrasion resistance — making it ideal for demanding sealing, hose, gasket, and dynamic applications across industries such as automotive, oil & gas, machinery, and general industrial use. Its ability to outperform standard nitrile rubber, while remaining more cost-effective than many high-end elastomers, makes HNBR a widely chosen material where reliability, durability, and media resistance are required. However, like all materials, selecting the correct grade and verifying compatibility with the intended operating environment are critical to achieving long-term, dependable performance.

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Please note – Like Nitrile, Hydrogenated Nitrile is not recommended for exposure to ethers, esters, ketones, or chlorinated hydrocarbons.

This Material Data Sheet section is to be used as a professional guide only. Eastern Seals (UK) Ltd may source their products from a variety of Quality Approved Suppliers and the data shown should not be relied upon by any purchaser without verification of material source.

Key Information

ES REF	Colour	Temp Range	Hardness	Notes	Data Sheet
HNBR70	BLACK	-40°C to +150°C	70	Standard type.	HNBR70
HNBR70 GR	GREEN	-40°C to +150°C	70	Standard type.	HNBR70 GR
HNBR70 FDA	BLACK	-30°C to +150°C	70	Food quality. Complies With FDA Regulation 21 CFR177.2600	HNBR70 FDA
HNBR80	BLACK	-40°C to +150°C	80	Standard type.	HNBR80
HNBR80 GR	GREEN	-40°C to +150°C	80	Standard type.	HNBR80 GR
HNBR90	BLACK	-40°C to +150°C	90	Standard type.	HNBR 90
HNBR90 PC	BLACK	-40°C to +150°C	90	Peroxide cured compound.	HNBR90 PC
HNBR90 GR PC	GREEN	-40°C to +150°C	90	Peroxide cured compound.	HNBR90 GR PC
HNBR90 AED	BLACK	-40°C to +150°C (Static) -15°C to +130°C (Dynamic)	90	NORSOK M-710 Approved / Rapid Gas Decompression.	HNBR90 AED
HNBR90 LT AED	BLACK	-55°C to +150°C (static) -40°C to +130°C (dynamic)	90	NORSOK M-710 Edition 3 & -ISO 23936-2 (Rapid gas decomperession resistance)	HNBR90 LT AED