Urethane (Castable, Millable, Foam)
Urethane rubber is prepared by the reaction of a long chain polyol with a diisocyanate. The polymers are based on either a polyether or a polyester backbone. Urethane is outstanding over most other elastomers in abrasion resistance and tensile strength.
Urethane rubber offers superior performance in hydraulic situations, where high pressures, shock loads or abrasion is anticipated. They also possess chemical compatibility similar to that of nitrile, offering good resistance to petroleum-based oils, hydrocarbon fuels, hydraulic fluids, oxidizing effects of ozone, aging effects of sunlight and good tear resistance. Good low-temperature flexibility is also a feature of many urethane rubbers.
Urethane is typically used in seals for high hydraulic pressure situations where parts are subject to wear and abrasion. It is also used for rolls, seals, bumpers, shock absorbers, rings, and wipers.