FabDigit

PNR · flame-retardant grade

PNR-FR

Properties of the FR condition, compared with the other PNR grades.

Choose for rail, building and electrical damping parts needing UL 94 V-0 / low smoke behaviour.

High cost $$$$
Request a quote in PNR-FRPNR overview

What is PNR-FR?

PNR-FR is PNR in the FR grade — choose for rail, building and electrical damping parts needing UL 94 V-0 / low smoke behaviour. PNR-FR has a tensile strength of 6 MPa (0.87 ksi), weaker than 82% of polymer grades. Elongation at break is 250% and the elastic modulus is 0 GPa (4.35×10⁻⁴ Msi). PNR-FR has a density of 1.35 g/cm³ (0.0488 lb/in³), heavier than 74% of polymer grades. Its glass-transition temperature is -25°C (-13 °F). SA40 is the default condition FabDigit quotes; FR is available on request or by drawing note.

Advantages

  • Forms and bends easily — 85/100, better than 82% of polymer grades
  • Ductile — tolerates forming and impact — 250%, better than 79% of polymer grades

Limitations

  • Difficult to machine — 20/100, worse than 97% of polymer grades
  • Low stiffness — 0 GPa (4.35×10⁻⁴ Msi), worse than 93% of polymer grades
  • High mold shrinkage — 2%, worse than 81% of polymer grades

PNR-FR properties

Typical room-temperature values for PNR-FR — 6 properties are specific to this condition; the rest are grade-level values shared by every PNR grade. Each bar shows where the value sits among the polymer grades in FabDigit's library — further right is higher.

Physical3

PNR-FR has a density of 1.35 g/cm³ (0.0488 lb/in³), heavier than 74% of polymer grades. Its glass-transition temperature is -25°C (-13 °F).

Density1.35 g/cm³0.05 lb/in³
Glass Transition (Tg)-25°C-13 °F
Water Absorption (24 h)0.5%

Mechanical8

PNR-FR has a tensile strength of 6 MPa (0.87 ksi), weaker than 82% of polymer grades. Elongation at break is 250% and the elastic modulus is 0 GPa (4.35×10⁻⁴ Msi).

Elastic (Young's) Modulus0 GPa4.35×10⁻⁴ Msi
Shear Modulus0 GPa1.45×10⁻⁴ Msi
Poisson's Ratio0.49
Tensile Strength (Ultimate)6 MPa0.87 ksi
Elongation at Break250%
Hardness, Shore A55 Shore A
Tear Strength15 kN/m85.7 lbf/in
Compression Set (22 h, 70 °C)35%

Thermal8

PNR-FR is rated for continuous service to 90°C (194 °F). It conducts heat at 0.2 W/m·K (0.116 BTU/hr·ft·°F), worse than 56% of polymer grades. Thermal expansion is 220 µm/m·K (122.2 µin/in·°F).

Thermal Conductivity0.2 W/m·K0.12 BTU/hr·ft·°F
Specific Heat Capacity1,800 J/kg·K0.43 BTU/lb·°F
Thermal Expansion (CTE, 20–100 °C)220 µm/m·K122 µin/in·°F
Max Service Temperature (continuous)90°C194 °F
Min Service Temperature-40°C-40 °F
Flammability (UL 94)V-0 achievable at ≥3 mm with ATH/phosphorus package
Limiting Oxygen Index29%
Max Service Temperature (short-term)120°C248 °F

Electrical4

PNR-FR is an electrical insulator with a dielectric strength of 18 kV/mm (457.2 V/mil) and a resistivity of 1×10¹¹ Ω·m.

Electrical Resistivity1×10¹¹ Ω·m3.94×10¹⁸ µΩ·in
Dielectric Strength18 kV/mm457 V/mil
Dielectric Constant (1 MHz)3.5
Volume Resistivity1×10¹³ Ω·cm

Chemical & Environmental2

UV resistance is fair.

UV / Weathering ResistanceFair35/100
Chemical Resistance SummaryGood resistance to water, dilute acids/alkalis and alcohols; swells strongly in hydrocarbons, aromatics and chlorinated solvents (this oil-uptake is exploited in sorbent grades); poor ozone/UV resistance without protective package.

Sustainability4

Producing a kilogram of PNR-FR takes about 105 MJ of energy and emits 4.5 kg of CO₂ — more than 54% of polymer grades. Typical recycled content is 0%.

Embodied Energy (primary production)105 MJ/kg45,142 BTU/lb
Embodied Carbon (primary production)4.5 kg CO₂/kg
Embodied Water180 L/kg21.6 gal/lb
Typical Recycled Content0%

Manufacturability4

PNR-FR's machinability is poor (20/100, worse than 97% of polymer grades); formability excellent (85/100).

MachinabilityPoor20/100
Formability (cold)Excellent85/100
Mold Shrinkage2%
Mold Temperature (typ.)160°C320 °F

Values are nominal handbook figures for design screening. Certified mill or lot data ships with every FabDigit order on request.

Other PNR grades and fills

PNR is also supplied in 8 other conditions. The full side-by-side table is on the PNR overview.

Working with PNR-FR

Is PNR easy to machine?

Too soft and tacky for conventional cutting — use water-jet, die cutting or cryogenic trimming; freeze before grinding.

Can PNR be welded?

Not weldable; join by co-vulcanization, adhesive bonding (cyanoacrylate/polyurethane after surface priming) or mechanical capture.

Can PNR be formed, bent or molded?

Mix on cold two-roll mill or internal mixer at low temperature (oil is absorbed rapidly), then compression/transfer/injection mold and cure 5–20 min at 150–170 °C with sulfur or peroxide.

What surface finishes work on PNR?

No plating or painting; surface can be textured in the mold, dusted with talc/silicone to kill tack, or coated with a flock/lacquer for abrasion and oil-bleed control.

PNR 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.

ElementSpec limit (wt %)Nominal
extender oil (naphthenic/paraffinic or ephr on polymer; sets hardness and Tg of the compound50 – 500200
carbon black / mineral fillerphr, reinforcement0 – 10030
sulfur or peroxide cure system + activatphr2 – 85
antioxidant / antiozonantphr1 – 32
polynorbornene (bicyclo[2.2.1]hept-2-enebase polymer, Mw typically >2×10^6 g/mol, ~90% trans ring-opened unitsbalance—

PNR-FR — frequently asked

What is PNR-FR used for?

PNR-FR is typically used for vibration damping mounts, sound insulation and oil-extended soft compounds. In short: softest oil-extended elastomer; high-hysteresis damping compounds; shore A 15 achievable.

What is the tensile strength of PNR-FR?

PNR-FR has a typical tensile strength of 6 MPa (0.87 ksi) — weaker than 82% of polymer grades. Strength varies by condition: see the 9 listed tempers.

Is PNR-FR easy to machine?

Not especially — machinability is rated poor (20/100, worse than 97% of polymer grades). Too soft and tacky for conventional cutting — use water-jet, die cutting or cryogenic trimming; freeze before grinding.

Can PNR-FR be welded?

Not weldable; join by co-vulcanization, adhesive bonding (cyanoacrylate/polyurethane after surface priming) or mechanical capture.

What surface finishes work on PNR-FR?

No plating or painting; surface can be textured in the mold, dusted with talc/silicone to kill tack, or coated with a flock/lacquer for abrasion and oil-bleed control.

Can PNR-FR be formed, bent or molded?

Mix on cold two-roll mill or internal mixer at low temperature (oil is absorbed rapidly), then compression/transfer/injection mold and cure 5–20 min at 150–170 °C with sulfur or peroxide.

What is the maximum service temperature of PNR-FR?

PNR-FR is rated for continuous use to about 90°C (194 °F), and briefly to 120°C. Strength falls off well before that limit — check the elevated-temperature data for load-bearing parts.

Sources

  1. Norsorex APX polynorbornene technical data — Astrotech Advanced Elastomer Products / Zeon (2020)
  2. Rubber Technology Handbook — specialty elastomers chapter — Hanser (2012)
  3. Polymer Handbook (Tg and density of polynorbornene) — Wiley (2005)
  4. ASTM D2000 — classification system for rubber products — ASTM (2018)
  5. Norsorex (2025)

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.