HNBR FS
Grade
also Therban, Zetpol
FS = fully saturated (residual double bond < 1 %), peroxide cured
Maximum heat, ozone and oxidation life — use for 150–160 °C continuous oil service and sour-gas seals.
Values for the FS condition
Other HNBR grades and fills
HNBR is listed in 9 conditions; see the grade overview at HNBR.
Compare all 9 grades and fillsHide
| Grade · open for datasheet | Best for | Yield MPa | Tensile MPa | Elong. % | Hardness |
|---|---|---|---|---|---|
Soft compound, Shore A 60 | Pick when low sealing force / good conformity on rough flanges is needed at moderate pressure. | — | 20 | 350 | 15 Shore D |
Low-ACN low-temperature grade | Choose for cold-start flexibility down to about −45 °C (A/C, cold-climate belts) at the cost of some oil-swell resistance. | — | 22 | 330 | 22 Shore D |
Sulfur-cured partially hydrogenated compound | Cheaper, more flex-fatigue tolerant (belts, boots) but heat life is clearly lower than peroxide-cured HNBR. | — | 24 | 350 | 20 Shore D |
A70Default Peroxide-cured black compound, Shore A 70 | General-purpose HNBR seal/O-ring compound; best balance of sealability, heat life and dynamic properties. | — | 25 | 300 | 22 Shore D |
High acrylonitrile (≈44 %) oil/fuel-resistant grade | Use where minimum swell in aggressive oils, biodiesel or aromatic fuels matters more than cold flexibility. | — | 26 | 270 | 23 Shore D |
FSThis page Fully saturated (residual double bond < 1 %), peroxide cured | Maximum heat, ozone and oxidation life — use for 150–160 °C continuous oil service and sour-gas seals. | — | 26 | 280 | 23 Shore D |
High-modulus compound, Shore A 80 | Higher extrusion resistance for high-pressure static seals, back-up rings and rod seals. | — | 27 | 240 | 30 Shore D |
Very hard compound, Shore A 90 | Oilfield packer elements and anti-extrusion parts where high pressure and gas decompression are present. | — | 28 | 170 | 40 Shore D |
High-strength reinforced compound | Highly reinforced (fine carbon black, high polymer Mooney) stock for timing belts, rollers and abrasion-critical parts. | — | 31 | 220 | 29 Shore D |
What is HNBR FS?
HNBR FS is HNBR in the FS grade — maximum heat, ozone and oxidation life — use for 150–160 °C continuous oil service and sour-gas seals. HNBR FS has a tensile strength of 26 MPa (3.77 ksi), weaker than 65% of polymer grades. Elongation at break is 280% and the elastic modulus is 0.01 GPa (0.0011 Msi). HNBR FS has a density of 1.25 g/cm³ (0.0452 lb/in³), heavier than 64% of polymer grades. Its glass-transition temperature is -25°C (-13 °F). A70 is the default condition FabDigit quotes; FS is available on request or by drawing note.
Advantages
- Good UV / weathering resistance — 82/100, better than 87% of polymer grades
- Forms and bends easily — 89/100, better than 86% of polymer grades
- High service temperature — 160°C (320 °F), better than 81% of polymer grades
- Ductile — tolerates forming and impact — 280%, better than 80% of polymer grades
Limitations
- High mold shrinkage — 2.3%, worse than 89% of polymer grades
- Difficult to machine — 30/100, worse than 87% of polymer grades
- Absorbs moisture — dry before molding — 1%, worse than 84% of polymer grades
- Low stiffness — 0.01 GPa (0.0011 Msi), worse than 83% of polymer grades
HNBR FS properties
Typical room-temperature values for HNBR FS; 18 are specific to this condition. Other listed values are HNBR reference data and may not represent this condition. Bars are the position among polymer grades.
Physical3
HNBR FS has a density of 1.25 g/cm³ (0.0452 lb/in³), heavier than 64% of polymer grades. Its glass-transition temperature is -25°C (-13 °F).
Mechanical9
HNBR FS has a tensile strength of 26 MPa (3.77 ksi), weaker than 65% of polymer grades. Elongation at break is 280% and the elastic modulus is 0.01 GPa (0.0011 Msi).
Thermal7
HNBR FS is rated for continuous service to 160°C (320 °F). It conducts heat at 0.25 W/m·K (0.144 BTU/hr·ft·°F), better than 72% of polymer grades. Thermal expansion is 220 µm/m·K (122.2 µin/in·°F).
Electrical4
HNBR FS is an electrical insulator with a dielectric strength of 16 kV/mm (406.4 V/mil) and a resistivity of 1×10⁸ Ω·m.
Chemical & Environmental3
Corrosion resistance is excellent (86/100), better than 72% of polymer grades. UV resistance is very good.
Sustainability3
Producing a kilogram of HNBR FS takes about 130 MJ of energy and emits 5 kg of CO₂ — more than 77% of polymer grades. Typical recycled content is 0%.
Manufacturability5
HNBR FS's machinability is poor (30/100, worse than 87% of polymer grades); formability excellent (89/100).
Values are nominal handbook figures for design screening. Confirm any required mill or lot documentation when quoting.
Working with HNBR FS
Is HNBR easy to machine?
Cured HNBR is best cut by waterjet, die/kiss-cutting or cryogenic deflashing; conventional turning/milling needs sharp tools, air cooling and frozen or mandrel-supported parts to avoid tearing.
Can HNBR be welded?
Thermoset — cannot be welded; join by adhesive bonding (cyanoacrylate or epoxy after plasma/chemical surface activation) or by co-vulcanising to metal with phenolic/silane bonding agents.
Can HNBR be formed, bent or molded?
Compression, transfer or injection mould peroxide compounds at 175–200 °C with a post-cure of 2–4 h at 150–175 °C to develop full heat resistance and low compression set; keep mould release and mixing free of sulfur contamination.
What surface finishes work on HNBR?
Cryogenic tumble deflashing is standard; surfaces can be talc/PTFE-coated, plasma-treated or parylene-coated for low friction, and metal-to-rubber bonded assemblies are grit-blasted and primed before moulding.
HNBR chemical composition (wt %)
Limits by weight percent from the governing specification, written the way the spec states them — a single maximum for impurities, a range for alloying elements, and the base element as balance. Nominal is the typical mid-range value.
| Element | Spec limit (wt %) | Nominal |
|---|---|---|
| acrylonitrile (ACN) comonomerwt % of the polymer; 34–39 % typical for seal grades | 17 – 50 | 36 |
| carbon black (N330/N550/N770)phr in the compound; replaced by silica/silicate in light-coloured grades | 20 – 60 | 40 |
| peroxide cure system + coagent (TAIC/TACphr; sulfur/accelerator system in partially hydrogenated grades | 3 – 10 | 6 |
| plasticiser / ester or ether plasticiserphr, low-temperature and processing aid | 0 – 15 | 5 |
| ZnO, anti-oxidant (ZMTI/TMQ), processingphr | 3 – 10 | 6 |
| hydrogenated butadieneresidual double bond 0.3–5.5 mol % depending on saturation level | balance | — |
HNBR FS — frequently asked
What is HNBR FS used for?
HNBR FS is typically used for timing belts, automotive seals, oilfield seals and high-temp hoses. In short: heat-resistant NBR upgrade; 150 °C oil-resistant seals; costlier than NBR.
What is the tensile strength of HNBR FS?
HNBR FS has a typical tensile strength of 26 MPa (3.77 ksi) — weaker than 65% of polymer grades. Strength varies by condition: see the 9 listed tempers.
Is HNBR FS easy to machine?
Not especially — machinability is rated poor (30/100, worse than 87% of polymer grades). Cured HNBR is best cut by waterjet, die/kiss-cutting or cryogenic deflashing; conventional turning/milling needs sharp tools, air cooling and frozen or mandrel-supported parts to avoid tearing.
Can HNBR FS be welded?
Thermoset — cannot be welded; join by adhesive bonding (cyanoacrylate or epoxy after plasma/chemical surface activation) or by co-vulcanising to metal with phenolic/silane bonding agents.
What surface finishes work on HNBR FS?
Cryogenic tumble deflashing is standard; surfaces can be talc/PTFE-coated, plasma-treated or parylene-coated for low friction, and metal-to-rubber bonded assemblies are grit-blasted and primed before moulding.
Can HNBR FS be formed, bent or molded?
Compression, transfer or injection mould peroxide compounds at 175–200 °C with a post-cure of 2–4 h at 150–175 °C to develop full heat resistance and low compression set; keep mould release and mixing free of sulfur contamination.
What is the maximum service temperature of HNBR FS?
HNBR FS is rated for continuous use to about 160°C (320 °F), and briefly to 175°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.
Sources
- Therban HNBR product and compound data — Arlanxeo (2023)
- Zetpol hydrogenated nitrile rubber technical data — Zeon Chemicals (2022)
- Parker O-Ring Handbook ORD 5700 (HNBR/HSN compound section) — Parker Hannifin (2021)
- Engineered Materials Handbook Vol. 2: Engineering Plastics and Elastomers — ASM International (1988)
- ASTM D2000 — Classification System for Rubber Products in Automotive Applications — ASTM (2020)
- GB/T 528 / GB/T 531.1 rubber tensile and hardness test methods — SAC (2009)
Property data is compiled from published supplier and standards handbooks and normalised for comparison. Nothing on this page is a certification — request mill certs, CoC or material test reports with your order.