The production process of TPU involves first reacting polyester (polyether) polyols with isocyanates and chain extenders to form linear polymers (mostly via the one-shot method), then processing them into granular solids. Finally, they are heated and melted through extruders and injection molding machines, and cooled in molds to form the target products. The molecular structure of TPU is mostly linear, with little or no chemical cross-linking, and only a certain degree of physical cross-linking. As a result, TPU is inferior to CPU in load-bearing performance, wear resistance, and heat resistance. However, compared with CPU, TPU does not require a long post-curing process, so its production efficiency is significantly higher than that of CPU. It is suitable for rapid mass production of small, precision special-shaped parts, such as sealing rings and transmission belts.

The production process of CPU mostly adopts the prepolymer method (two-step method): first, polyester (polyether) polyols are reacted with isocyanates to form prepolymers, then the prepolymers are mixed with chain extenders, poured into molds, cured and molded at high temperature, and finally the molded CPU is subjected to a long post-curing treatment to obtain the target products. The molecular structure of CPU is a network cross-linked structure with a high degree of cross-linking, so CPU products have excellent mechanical properties such as wear resistance and tear resistance. However, compared with TPU, CPU has a longer production cycle, higher material consumption, and higher cost.

In summary, for small special-shaped parts (such as tongue pieces, special-shaped strips, etc.), if the requirements for mechanical properties and heat resistance of the material are relatively low, a large number of products need to be obtained quickly, and the price requirement is low, TPU is the preferred choice. For large special-shaped parts (such as rubber-coated wheels, large screen plates for coal mines, etc.) and high-performance small special-shaped parts (such as wear-resistant rubber rollers, rubber gears, etc.), CPU can better meet the usage requirements, although the price of CPU is higher. In addition, TPU can be melted for secondary plastic molding at high temperature and can be recycled, while CPU cannot be recycled after molding and curing. Therefore, when there are requirements for environmental protection and recycling, TPU is the preferred choice.