Combining good chemical resistance with excellent weathering characteristics sets polyurethane apart from most other thermoplastics. It has exceptional resistance to most gasolines, oils, kerosene, and other petroleum-based chemicals, making PU tubing and hose, also know as PUR tubing and hose, an ideal choice for fuel lines (although additives in today’s gasoline and petroleum products warrant field testing).

The two basic formulations of urethane, ester and ether, have some important differences. Water attacks ester-based urethane, causing a significant reduction in physical properties. Ether urethanes exhibit far superior hydrolytic stability, especially in humid environments. Ether-based materials also resist fungus growth better than ester-based materials.