Polyurethane, commonly abbreviated as PU, is a class of polymers that contain many repeated urethane (carbamate) groups (-NHCOO-) in their molecular chains. Polyurethane elastomers represent a particularly unique category among elastomers. From a molecular structure perspective, polyurethane elastomers are block copolymers, typically composed of soft segments made from low-molecular-weight polyols (flexible long chains) and hard segments formed by diisocyanates and chain extenders. The hard and soft segments alternate and form repeating structural units. In addition to containing urethane groups, polyurethane molecules can form hydrogen bonds both within and between molecules, and the soft and hard segments can form microphases and achieve microphase separation. These structural characteristics endow polyurethane elastomers with excellent wear resistance and toughness, earning them the reputation of being "wear-resistant rubber."
What are the advantages of polyurethane elastomers?
Polyurethane elastomers possess excellent comprehensive properties, with a modulus that lies between that of general rubbers and plastics. They have the following characteristics:
1. High strength and elasticity, maintaining high elasticity over a wide range of hardness (from as low as Shore A10 to as high as Shore D90);
2. Higher load-bearing capacity than other elastomers at the same hardness level;
3. Outstanding wear resistance, with wear resistance that is 2 to 10 times that of natural rubber;
4. Excellent resistance to oils and chemicals;
5. Superior UV, oxidation, ozone, radiation, and weather resistance;
6. Excellent fatigue resistance and vibration damping properties, suitable for high-frequency flexing applications;
7. High impact resistance; good low-temperature flexibility; no need for plasticizers to achieve the desired hardness, thus avoiding issues related to plasticizer migration;
8. Special formulations of polyurethane can withstand high temperatures up to 150°C;
9. Diverse and simple molding processes, with low processing and mold costs.
Compared to metal materials, its characteristics are:
1. Lightweight
2. Low noise
3. Wear-resistant
4. Low processing costs
5. Strong corrosion resistance
Compared to plastics, its characteristics are:
1. Does not become brittle
2. Good elastic memory
3. Excellent wear resistance
Compared to rubber, its characteristics are:
1. Superior wear resistance
2. More resistant to cutting and tearing
3. Higher load-bearing capacity
4. Can be transparent or semi-transparent
5. Better chemical and weather resistance
6. Wider range of hardness
7. Diverse processing methods, lower mold and processing costs
More environmentally friendly, healthier, and energy-efficient