Toray Industries, Inc.

Hajime Arai

Yoshiaki Sato

Kiyoshi Nakagawa

Isoo Saito

Kotaro Fujioka

Hideo Saruyama

A polyester multifilament yarn which has the following properties: an initial modulus (Mi) of 90 to 130 grams per denier, a terminal modulus (Mt), a shrinkage index value (.DELTA.S/IV) of 2 to 8 percent, a birefringence (.DELTA.n) of 165.times.10.sup.-3 to 190.times.10.sup.3, a crystalline orientation function (fc) of 0.93 to 0.97, a crystal size (D) 47 to 55 angstroms, a long period (Lp) of 130 to 145 angstroms, a molecular orientation index in the amorphous region (F) of 0.80 to 0.92, and a concentration of carboxyl end groups (--COOH) of 0 to 25 equivalents per 10.sup.6 grams of the polymer is disclosed. The yarn is improved in modulus and shrinkage. A textile reinforcement for tire cord obtained from the multifilament yarn, exhibits exceedingly improved resistance to fatigue and durability to heating. The polyester multifilament yarn is obtained by (A) melt-spinning polymer at high speed (B) solidifying the spun yarn through a solidification zone comprising (a) a heating zone and (b) cooling zone adjacent to the lower part of the heating zone, and (C) withdrawing the solidified yarn, and (D) hot drawing the yarn.

Polyester multifilament yarn and process for producing thereof

A separable unitary composite fiber of the type having a substantially uniformly shaped transverse cross-section along its length and comprised of at least two different polymer components, one of which is soluble in a given solvent and the other of which is relatively insoluble in the given solvent; a plurality of segments of the relatively insoluble polymer component being isolated from each other by the intervening soluble polymer component in the transverse cross-section of the composite fiber. The composite fiber is characterized in that the soluble polymer component is a polyester comprised of 80 to 97% by mole of ethylene terephthalate units and 3 to 20% by mole of ethylene 5-sodium-sulfoisophthalate units, and the relatively insoluble polymer component is a fiber-forming polyester and/or polyamide.

Separable composite fiber and process for producing same

Disclosed is a bulky yarn made from a thermoplastic multifilament yarn. Each of the individual filaments forming the yarn has a randomly varying thermal shrinkage along its length. The filaments in the cross-section of the yarn also have randomly varying thermal shrinkages. The bulky yarn forms a plurality of loops having a stable and compact configuration, while the number of filament slack portions which project outwardly from the yarn surface is significantly decreased. A method for producing a bulky yarn possessing the above-mentioned construction is also disclosed. In the method, individual filaments forming the multifilament yarn are interlaced with each other, before or after which the yarn is subjected to a so-called random heat treatment. The interlaced and randomly heat-treated yarn is supplied at an over-feed condition to a fluid turbulent flow region which causes the individual filaments to form a plurality of loops and entanglements, and then the yarn is wound onto a package.

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Mishima, Japan

Hajime Arai