| Property | Value |
|---|---|
| Temperature range | -40 °C to +90 °C |
| Hardness | 15–80 Shore A, and down to single digits when oil-extended |
| Best at | Damping, very low durometer, energy absorption |
| Contains fluorine | No |
Why it goes softer than anything else
The polymer has an unusually high molecular weight and a structure that absorbs plasticiser without turning into a paste. A conventional compound loaded with that much oil would bleed, lose all tear strength, and take permanent set. Polynorbornene holds together, which is why it owns the bottom of the hardness range.
That matters when a part has to conform to an irregular surface under almost no load, or cushion something fragile, or damp a resonance without adding stiffness. A 20 Shore A natural rubber part and a 20 Shore A polynorbornene part behave very differently under a cyclic load: the natural rubber springs back, the polynorbornene absorbs.
How we compound and test it
The oil level is the formulation. Move it and you move hardness, damping, and set together, so the specification has to say which of those governs the part before we mix. We hold the damping behaviour on a dynamic test rather than inferring it from a durometer reading, because hardness alone tells you almost nothing about how this family performs in service.
It cures with a conventional sulfur system and molds cleanly, but low-durometer parts need care coming out of the tool. Geometry that would be routine at 60 Shore A can tear at 15.
The two mistakes buyers make
The first is specifying it as a seal. It is not oil resistant, its compression set is mediocre by sealing standards, and its temperature ceiling is modest. If the part has to hold pressure over years, this is the wrong family.
The second is ordering by hardness with no other requirement. Two polynorbornene compounds at the same durometer can differ enormously in how much energy they absorb, which is usually the property the part was actually chosen for. Tell us what the part has to damp, as well as how soft it should feel.
Typical uses
- Vibration and shock damping mounts where stiffness must stay low
- Very low durometer pads, cushions, and conforming seals against irregular surfaces
- Anti-slip and grip components
- Printing and paper-handling rollers
- Noise damping layers in machinery