| 摘要 |
PROBLEM TO BE SOLVED: To provide a method for inexpensively and efficiently producing an ultrafine denier staple fiber by using a bundle of large denier undrawn yarns without the need of a specific piece of equipment. SOLUTION: This method for producing an ultrafine denier staple fiber comprises; subjecting a bundle of polyester low-orientational undrawn yarns with a structural integrity parameter (ε0.2 ) of >=45% to the first draw treatment at (Tg+20) to (Tm-120) deg.C by setting the draw ratio to be >=80% the cut drawing ratio of the undrawn yarn and the drawn tension to be <=0.04 g/d, and conducting the second draw treatment at >=(Tg+30) deg.C, thus obtaining a staple fiber of <=0.7 d single yarn denier. Noted that Tg: a glass transition temperature ( deg.C) of undrawn yarn, and Tm: a melting temperature ( deg.C) of undrawn yarn.
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