Textiles: spinning – twisting – and twining – Strand structure – Multifilament yarns
Patent
1989-06-15
1990-11-13
Petrakes, John
Textiles: spinning, twisting, and twining
Strand structure
Multifilament yarns
28156, 57208, 57245, 57288, 57289, 428224, 428229, D02G 302, D02G 324, D02G 338
Patent
active
049693220
DESCRIPTION:
BRIEF SUMMARY
TECHNICAL FIELD
The present invention relates to a process for the production of an ultra-soft and flat multifilament yarn which is extremely soft and has a unique touch, and to an ultra-soft and flat multifilament yarn produced by the above process, and an ultra-soft fabric composed of the above-mentioned multifilament yarn.
BACKGROUND ART
Synthetic fibers usually have glass transition temperatures (also called second-order transition temperatures), and at temperatures lower than these temperatures, polymer molecules are frozen and molecular movement becomes difficult. Therefore, when drawing such fibers, usually the drawing temperature is the glass transition point of the fibers or higher and the drawing procedure is carried out in conditions such that the polymer molecules are easily movable. When a synthetic fiber is forcibly drawn while the polymer molecules of the fiber are frozen at the glass transition temperature or lower, however, the polymer molecules will not be oriented, and accordingly, fibers exhibiting a specific touch entirely different from that of the drawn fibers of the prior art are obtained (note, if the frozen polymer molecules are forcibly drawn by the method of the prior art, stretching irregularities will be inevitably formed, and thus a product having a uniform appearance cannot be obtained). Therefore, the drawing of synthetic fibers at a temperature corresponding to the glass transition temperature thereof or lower is the same as that used in the process for production of the Thick & Thin fiber, as also shown in Japanese Patent Publication (Kokoku) No. 58-44762, and accordingly, it is impossible to obtain only a specific touch without generating drawing irregularities. Also, since this drawing at the glass transition point or lower forcibly stretches the frozen polymer molecules, a very strong force is required therefor and thus many problems arise in that slippage of the filaments occurs at peripheral surfaces of the rollers, which leads to fluffs and the generation of laps. Also, a problem arises in that the productivity of the drawn filament yarn is lowered.
DISCLOSURE OF THE INVENTION
The present invention is intended to provide a process for producing an ultra-soft and flat multifilament yarn, which is very soft and has a unique touch, when the polymer molecules are frozen, without changing the cross-sectional profile of the multifilament and without imparting crimps thereto, and to provide an ultra-soft and flat multifilament yarn comprising uniformly drawn multifilaments having a uniform appearance and properties, and an ultra-soft, flat multifilament yarn fabric obtained therefrom.
The process of the present invention for preparing the ultra-soft, flat multifilament yarn comprises applying a false twisting procedure including twist applying and twist releasing operations to two or more types of multifilament yarns having different drawing properties and arranged in parallel with each other, characterized in that the false twisting procedure is carried out at a temperature of 120.degree. C. or lower, and the resultant false twisted composite yarn is subjected to a heat treatment at a temperature of 130.degree. C. or more in a successive procedure carried out thereafter.
In the present invention, the term flat multifilament refers to a straight multifilament having substantially no crimp.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1 (a), (b) and (c) are side views of synthetic filaments of the prior art illustrating the drawing step of the filaments, wherein FIG. 1 (a) shows a side view of an unstretched synthetic filament, FIG. 1 (b) shows a side view of a uniformly drawn synthetic filament, and FIG. 1 (c) shows a side view of an unevenly stretched synthetic filament;
FIGS. 2 (a), (b) and (c) are side views of filament yarns arranged in parallel and comprising two types of synthetic filaments having different drawing properties, illustrating a false twisting procedure for the parallel filament yarns by the process of the present invention, wherein FIG. 2 (a) shows
REFERENCES:
patent: 4145870 (1979-03-01), Klee et al.
patent: 4170867 (1979-10-01), Leininger
patent: 4226079 (1980-10-01), Mountney et al.
patent: 4262481 (1981-04-01), Otaki et al.
patent: 4307565 (1981-12-01), Sasaki et al.
patent: 4365466 (1982-12-01), Horiuchi et al.
Japanese Textile Machinary Association (Osaka), "Manual of Filament Processing Technology", vol. 1, (May 31, 1984), pp. 103 to 105.
Sasaki Yoshiyuki
Tani Masayuki
Petrakes John
Teijin Limited
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