| 摘要 |
PROBLEM TO BE SOLVED: To provide a producing method of heat-self elongation-type polyester staple fiber capable of inexpensively and high-productively producing staple fibers having no fluctuation of properties and a heat-self elongation property by using a low-oriented undrawn yarn. SOLUTION: A polyester low-oriented undrawn yarn bundle Y containing a main repeating unit of ethylene terephthalate and having >=45% of a structure- conformity parameter (ε0.2 ) is drawn under the following condition (1), successively subjecting to relaxed heat treatment under the following condition (2), imparting crimping, drying at <= Tg and cutting to obtain the objective heat-self elongation-type polyester staple fiber. (1) Temperature: (Tg+20)-(Tm-100) deg.C, Tg: glass transition temperature ( deg.C) of the polyester constituting the undrawn yarn bundle, Tm: melting point of the polyester constituting the undrawn yarn bundle, drawing tension: <=0.07g/d, (2) temperature: >=(Tg+40) deg.C, relaxation percentage: 5-30%, time: 0.5-10sec. |
