heat

Polyurethanes can operate at a continuous temperature of about 160 degrees F. and intermittently at about 180 degrees F. In most dynamic applications we recommend staying at temperatures below 160°F (70°C ). The normal, high property working range is (-70°C to 70°C). At 160°F (70°C) the properties of the elastomer begin to show a decline. The bond between urethane and metal weakens considerably above 160°F (70°C).

moisture

Polyurethanes can operate for years in the presence of moisture but, when the combination of moisture and heat occur the length of operation time is reduced dramatically. Polyurethanes have limited resistance to water. Continuous immersion in water above 50 degrees C can result in hydraulic breakdown and for this reason a maximum upper limit of around 70 degrees C under these conditions should apply.

chemicals

Certain chemicals can limit the use of polyurethanes as well. Strong acids and bases, aromatic solvents and some esters can have a detrimental effect on polyurethanes. Certain chemicals such as concentrated acids and polar solvents attack urethanes, and urethanes should not be put into continuous service in these environments. Rubber has better resistance against H2S.