Characteristics of polyurethane
　　
　　（1） excellent wear resistance: the wear resistance is the highest of all rubbers. The laboratory test results show that the wear resistance of ur is 3-5 times of that of natural rubber, and it is often up to 10 times in practical application.
　　
　　（2） it has high strength and good elasticity in the hardness range from shore A60 to shore A70.
　　
　　（3） good cushioning and shock absorption. At room temperature, ur shock absorber can absorb 10% ~ 20% vibration energy. The higher the vibration frequency, the greater the energy absorption.
　　
　　（4） good oil resistance and drug resistance. Ur has less affinity with non-polar mineral oil, and is almost free from erosion in fuel oil （such as kerosene, gasoline） and mechanical oil （such as hydraulic oil, engine oil, lubricating oil, etc.）， which is much better than general rubber and comparable to NBR. The disadvantage is that the swelling property of alcohol, ester, ketone and aromatics is large.
　　
　　（5） the friction coefficient is higher, generally above 0.5.
　　
　　（6） low temperature resistance, ozone resistance, radiation resistance, electrical insulation and good bonding performance.
　　
　　Fold
　　
　　Typical shrinkage 0.0045 in / in
　　
　　Coefficient of thermal expansion 5-8 × 10-5in / （in ·° C）
　　
　　Elongation 2-3%
　　
　　Vicat softening point 225 ° f