摘要:
A thermoplastic polyurethane elastomer containing a very small amount of small grains, and having a high molecular weight and a narrow molecular-weight distribution. Such high-quality thermoplastic polyurethane is excellent in melt moldability and allows to prevent yarn breakage in producing fibers by melt spinning, for example. Such polyurethane elastomer can be produced by melt-polymerizing a prepolymer and a low-molecular diol at a relatively high temperature in a short period of time. This invention also provides an apparatus for producing the polyurethane elastomer, and fibers formed of said elastomer.