Toray Industries, Inc.

Yoshio Aratani

Kiyoshi Nakagawa

Masatoshi Mineo

Yukio Otaki

Shiro Nishiumi

Haruhiko Kusakabe

Yoshio Tatsuoka

A potentially bulky, processed yarn which is a substantially non-interlaced multifilament yarn of a thermoplastic synthetic fiber satisfying the characteristic values of R.sub.max /R.ltoreq.2.5, .DELTA.S.sub.5 .gtoreq.1.5, .DELTA.S.sub.50 .ltoreq.3.0, Y.gtoreq.1.3 and X.sub.T --X.ltoreq.1.0, where R.sub.max is maximum tension fluctuation width, R is average tension fluctuation width of a normal portion, .DELTA.S.sub.5 is difference in maximum shrinkage among each filament of a sample having a length of 5 cm, .DELTA.S.sub.50 is difference in maximum shrinkage among each filament of a sample having a length of 50 cm, X.sub.T is maximum tension, X is average tension and Y is degree of bulkiness/dry heat shrinkage. A bulky, processed yarn is obtained by supplying a substantially non-twisted thermoplastic multifilament yarn to a heated body under a tension of 10-120 mg/d with monofilaments contacting said heated body at an imaginary point of contact and monofilaments not contacting said heated body at said imaginary point of contact, at the same time contacting said yarn with said heated body within such a short period of time that the heat of said heated body may not uniformly be conducted to the multifilament yarn, and either immediately thereafter winding the yarn, or in the alternative not winding said yarn immediately thereafter, but contacting said yarn with another heated body under conditions not substantially elongating the yarn, thereby eliminating produced loops, and thereafter winding said yarn.

Potentially bulky yarn

A process for producing a potentially bulky yarn which is a substantially non-interlaced multifilament yarn of a thermoplastic synthetic fiber satisfying the characteristic values of R.sub.max /R.ltoreq.2.5, .DELTA.S.sub.5 .gtoreq.1.5, .DELTA.S.sub.50 .ltoreq.3.0, Y.gtoreq.1.3 and X.sub.T -X.ltoreq.1.0, where R.sub.max is maximum tension fluctuation width, R is average tension fluctuation width of a normal portion, .DELTA.S.sub.5 is difference in maximum shrinkage among each filament of a sample having a length of 5 cm, .DELTA.S.sub.50 is difference in maximum shrinkage among each filament of a sample having a length of 50 cm, X.sub.T is maximum tension, X is average tension and Y is degree of bulkiness/dry heat shrinkage.

Process for producing a potentially bulky yarn

A textured polyester yarn having improved variation in dyeability along its length is composed of a plurality of individual filaments each having thick and thin sections randomly distributed along the filament axis, said yarn having an Uster evenness value of 1.0 to 10.0%, a T index of 3 to 30 and a variation in reflected light intensity in a continuous dyeing test of .+-.0.15 to .+-.0.80 and said yarn preferably having not-untwisted portions containing genuine twists of a fixed direction intermittently retained at random along its length. The yarn is produced by false twisting a polyester yarn composed of a plurality of individual filaments each having variation in cross-sectional area along its length, in which the thick sections have a birefringence of 15 to 80.times.10.sup.-3 and the thin sections have a birefringence of 90 to 200+10.sup.-3, at a temperature of not lower than 180.degree. C and under a twisting tension of 0.05 to 0.8 g/d with a variation with respect to the average twisting tension of .+-.5 to .+-.20%.

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Otsu, Japan

Yoshio Aratani