The strength of a material to resist degradation by chemicals
Polyurethane resists degradation to a long list of chemicals. This makes it suitable for many industrial applications. Polyurethane’s chemical resistance is dependent on its formulation. It is important to identify any chemicals that will be present in your application so that we can tailor the formulation to have the best resistance.
Polyurethane’s chemical resistance varies between polyurethane formulations. In general: Polyester type polyurethane is more resistant to oils, solvents, and weak acids/bases. And polyether type polyurethane is more resistant to water exposure.
For example:
– Polyurethanes can remain in water at 20°. Polyester polyurethanes in contact with warm water or steam at about 60°C or higher undergo irreversible degradation (hydrolysis) of the polyester chains. Polyurethane made from polyether in place of polyester are not sensitive to hydrolytic degradation and are an even better solution in such cases.
– Polyurethanes offer excellent resistance to pure mineral oils and fats. ASTM test oils 1, 2 and 3 causes no loss of strength at 20°C or after three weeks of exposure at 100°C. PU are also resistant to diesel, kerosene and the FAM test fluid Fuel A (ASTM D 471), showing no loss of strength, and show limited resistance to Fuels B and C.
Systems resistance
| # | PU System | Hydrolysis | Oils | Solvents |
|---|---|---|---|---|
| 1 | GI – E2 Series | Very good | Good | Good |
| 2 | GI – E4 Series | Good | Very good | Very good |
| 3 | GI – V Series | Good | Very good | Very good |
