Mitsubishi Rayon Company, Limited

Ryuichi Nakazono

Takashi Kaneko

Kazuya Chimura

Kenichi Sakunaga

Masao Kawashima

Shunichi Takashima

Hisao Anzai

Hiroshi Iwata

Toru Maeda

Kazushi Shimada

Kazunori Kagawa

Hiroyuki Ota

Kenji Tamura

Eiji Umemura

Kenji Takoi

Method for producing a crimped yarn in which a thermoplastic yarn is false twisted at a speed exceeding 300 m/min. by using a twisting tube comprising a friction twisting surface of wear-resistant material having a high frictional coefficient, the false twisting being performed under a particular relationship among the yarn speed, surface speed of the twisting tube, denier of the yarn, and the yarn tension at the inlet and outlet sides of the twisting tube.

Method for producing a crimped yarn

There is provided a filament of improved light transmission having a sheath-core composite structure formed of a methyl methacrylate polymer core material and a fluorine-containing polymer sheath material. The light transmitting filament is characterized in that the methyl methacrylate polymer core material is prepared by the specific procedure of continuous bulk polymerization and subsequent removal of volatile contents, wherein the polymerization is performed in a continuously and thoroughly stirred reaction vessel at a low catalyst concentration and a relatively high temperature and with improved conversion. The light transmitting filament possesses an absorption coefficient (k) of no greater than 6 .times. 10.sup.-.sup.3 cm.sup.-.sup.1.

Light transmitting filament

Polyester fibers which are characterized by excellent dyeability are produced by spinning a polymer obtained by an ester interchange reaction of 60 to 95% by weight of a polyester, containing at least 95 mol % of ethylene terephthalate units, and 40 to 5% by weight of a polyester containing at least 85 mol % of tetramethylene terephthalate units, wherein the filamentary polymer has a melting point Tm (.degree. C) of Tm.sub.o -5(.degree. C) .gtoreq. Tm .gtoreq. Tm.sub.o -20(.degree. C)(wherein Tm.sub.o is the melting point of the polyester containing at least 95 mol % of ethylene terephthalate unit) and a crystallizing temperature of 170.degree. C or higher.

Polyester fibers having excellent dyeability

A novel unitary spun polyester composite filament is provided. The composite filament consists essentially of (a) a block copolymer, as the first component, having a melting point of not lower than 170.degree.C and consisting essentially of 35-80 wt. % of a polyester, as the hard segment, predominantly containing a tetramethylene terephthalate unit and 20-65 wt. % of a long-chain glycol having a molecular weight of 500 to 5,000 as the soft segment, and (b) a polyester, as the second component, predominantly containing a tetramethylene terephthalate unit. The composite filament produces crimps superior particularly in percent of crimp and percent of crimp retentivity when drawn and relaxed.

Unitary spun composite filament

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Otake, Japan

Ryuichi Nakazono