Thermoplastic PU (TPU for short), also known as PU thermoplastic, is a linear block copolymer composed of oligomer polyol soft segment and diisocyanate-chain extender hard segment. It is a kind of polyurethane elastomer that can be plasticized by heating and dissolved by solvent.

The characteristics of TPU

Compared with general plastics and rubber materials, TPU has a wide range of hard layer, outstanding mechanical properties, excellent high/low temperature resistance, good processing performance, excellent environmental protection performance, strong plasticity, strong designability, good transparency and other excellent characteristics. It has both the high elasticity of rubber materials and the high strength of engineering plastics. Because of its excellent performance and wide application, it has become one of the important thermoplastic elastomer materials.

Compared to CPU and MPU, the molecular chain of TPU is basically linear, with little or no chemical cross-linking in the chemical structure. There are many physical crosslinks formed by hydrogen bonds between linear polyurethane molecular chains, which strengthen the morphology of TPU, thus giving it many excellent properties, such as high modulus, high strength, excellent wear resistance, chemical resistance, hydrolysis resistance, high and low temperature and mold resistance.

The structure of TPU

TPU is A (AB) type block linear polymer, A stands for high molecular weight polymer polyol poly (ester or polyether, molecular weight 1000 ~ 6000), known as long chain; B stands for 2-12 straight chain carbon diols, called short chains.

In the structure of thermoplastic polyurethane elastomer, A chain segment is called soft chain segment, with flexible and soft characteristics, so that TPU has extensibility; The ammonia ester chain generated by the reaction of B chain segment and isocyanate is called hard chain segment, which has rigid and hard properties. People make TPU products with different physical and mechanical properties by adjusting the proportion of A and B chain segments.

The classification of TPU

According to the soft segment structure can be divided into polyester type, polyether type and butadiene type, they contain ester group, ether group or butadiene group respectively.

According to the hard segment structure, it can be divided into ammonia ester type and ammonia ester urea type, which are obtained by diol chain extender or diamine chain extender respectively. The common division is divided into polyester type and polyether type.