A TPU is a multi-phase block copolymer created when three basic raw materials are combined in a specific way. The individual components required to produce a TPU are:
- A polyol or long-chain diol
- A chain extender or short-chain diol
- A diisocyanate.
The soft block, comprising a polyol and an isocyanate, is responsible for the flexible, elastic character of a TPU.
The hard block, constructed from a chain extender and an isocyanate, imparts toughness and other physical performance properties.