| 摘要 |
PROBLEM TO BE SOLVED: To provide a polytrimehylene terephthalate (PTT) fiber having a high elastic limit range and a low heat shrinkage, concretely exhibiting >=10% elastic limit range and at least 5% elastic limit range after its heat treatment, and a method for producing the same fiber. SOLUTION: This PTT fiber constituted by >=90 mol % trimethylene terephthalate recurring units is provided b having 0.7-1.3 dl/g intrinsic viscosity of the trimethylene terephthalate, >=90% degree of crystal orientation measured by a wide angle X-ray scattering method, 20-39% breaking elongation and 2-7% boiling water shrinkage, and the method for producing the PTT fiber is provided by melt-spinning the trimethylene terephthalate resin constituted by >=90 mol % trimethylene terephthalate recurring units and having 0.7-1.3 dl/g intrinsic viscosity, stretching the fiber by <40% of its breaking elongation, performing a heat treatment at 0-4% relaxing rate to make 2-7% boiling water shrinkage. |
