Cast polyurethanes fall into two main classes; polyester (AU) and polyether (EU). These materials have outstanding tensile strength and abrasion resistance. Our polyurethane materials are based on diphenylmethane diisocyanate (MDI).
- They also have good resistance to oxidation, ozone and petroleum based fuels and oils.
- Polyesters have physical properties slightly superior to those of polyethers.
- Electrical properties are fairly good.
- Unlike polyethers, polyesters can be affected by hot water and high humidity and their resistance to acids and alkalis is low. Maximum operating temperatures should not significantly exceed ambient.
- Compression set and creep properties are only fair.
- In view of the high hysteresis (damping) of most polyurethanes, care must be taken for applications involving high frequency deformation and tyre/wheel speeds of over 8 mph.
- As these materials are liquid cast, tooling prices tend to be lower than for heat and pressure moulded rubbers.
- Typical applications include abrasion-resistant coatings and linings, diaphragms, gaskets, haul-off pads, hoses and seals.