Thermoplastic polyurethane elastomer, also known as thermoplastic polyurethane rubber, referred to as TPU, is a (AB) n-type block linear polymer, A is polyester or polyether with high molecular weight (1000-6000), B is a linear polymer containing 2-12 Chain carbon atoms of the diol, the chemical structure between the AB segments is linked by a diisocyanate, usually MDI. Thermoplastic polyurethane rubber is cross-linked by intermolecular hydrogen bonds or lightly cross-linked between macromolecular chains. As the temperature increases or decreases, these two cross-linked structures are reversible. In the molten state or solution state, the intermolecular force weakens, and after cooling or solvent volatilization, there is a strong intermolecular force connecting together, restoring the performance of the original solid.

Thermoplastic polyurethane elastomers have two types: polyester type and polyether type, white random spherical or columnar particles, relative density 1.10-1.25, polyether type relative density is smaller than polyester type. The glass transition temperature of polyether type is 100.6-106.1°C, and the glass transition temperature of polyester type is 108.9-122.8°C. The brittleness temperature of polyether type and polyester type is lower than -62℃, and the low temperature resistance of polyether type is better than that of polyester type.
The outstanding features of thermoplastic polyurethane elastomers are excellent wear resistance, excellent ozone resistance, high hardness, high strength, good elasticity, low temperature resistance, good oil resistance, chemical resistance and environmental resistance. The hydrolytic stability of the ester type is much higher than that of the polyester type.