Toray Industries, Inc.

Hiroo Katsuta

Yoshitsugu Funatsu

Yuhei Maeda

Shunsuke Horiuchi

Daisuke Yamamoto

Takaaki Mihara

Norio Suzuki

Hidekazu Kano

Reo Mitsunaga

Masanori Endo

Kirita Sato

Chieko Kawamata

Yusuke Ono

Yuhei Yoshitsugu Maeda

A method of producing a liquid crystalline polyester fiber includes subjecting a yarn prepared by melt spinning a liquid crystalline polyester to a solid-phase polymerization after applying inorganic particles (A) and a phosphate-based compound (B) to the yarn. The method can optionally include cleaning the liquid crystalline polyester fiber after the solid-phase polymerization.

Method of producing liquid crystal polyester fibers

A poly(phenylene sulfide) fiber contains 1-10% by weight of a poly(phenylene sulfide) oligomer having a weight-average molecular weight of 5,000 or less, has a difference between a cold crystallization heat quantity (&#x394;Hc) and a crystal melting heat quantity (&#x394;Hm) during temperature rising in DSC, &#x394;Hm&#x2212;&#x394;Hc, of 25 J/g or larger, and has an elongation of less than 40% and a strength of 3.0 cN/dtex or higher. The poly(phenylene sulfide) fiber has high heat resistance and chemical resistance and high strength and, despite this, has excellent suitability for high-order processing, e.g., thermal shapability, because the amorphous parts thereof have high molecular movability.

Polyphenylene sulfide fibers, and manufacturing method therefor

A poly(phenylene sulfide) fiber changes little in fiber structure and has excellent long-term heat resistance. Namely, the poly(phenylene sulfide) fiber has a degree of crystallization of 45.0% or higher, a content of movable amorphous components of 15.0% or less, and a weight-average molecular weight of 300,000 or less.

Polyphenylene sulfide fiber

A liquid crystalline polyester fiber which exhibits a half width of endothermic peak (Tm) of 15&#xb0; C. or above as observed in differential calorimetry under heating from 50&#xb0; C. at a temperature elevation rate of 20&#xb0; C./min and a strength of 12.0 cN/dtex or more; and a process for production of the same. A liquid crystalline polyester fiber which is excellent in abrasion resistance and lengthwise uniformity and is improved in weavability and quality of fabric and which is characterized by a small single-fiber fineness can be efficiently produced without impairing the characteristics inherent in fabric made of liquid crystalline polyester fiber produced by solid phase polymerization, namely, high strength, high elastic modulus and excellent thermal resistance.

Liquid crystalline polyester fiber and process for production of the same

Disclosed are liquid crystal polyester fibers, which have a peak half-width of 15&#xb0; C. or greater at an endothermic peak (Tm1) observed by differential calorimetry under a temperature elevation of 20&#xb0; C./minute from 50&#xb0; C., polystyrene equivalent weight average molecular weight of 250,000 or more and 2,000,000 or less, and a variable waveform of less than 10% in terms of the half inert diagram mass waveform determined by a Uster yarn irregularity tester. Also disclosed is a method for producing liquid crystal polyester fibers, wherein liquid crystal polyester fibers are formed into a package, the fibers are then subjected to solid-phase polymerization, and the solid-phase polymerized liquid crystal polyester fibers are unrolled from the package and successively heat treated without being once taken up. The heat treatment temperature is controlled at a temperature of the endothermic peak temperature (Tm1) of the solid-phase polymerized liquid crystal polyester fibers+60&#xb0; C. or higher, and the speeds of the fibers before and after heat treatment are regulated, respectively, by first and second rollers.

Liquid crystal polyester fibers and method for producing the same

A liquid crystalline polyester fiber which exhibits a half width of endothermic peak (Tm1) of 15&#xb0; C. or above as observed in differential calorimetry under heating from 50&#xb0; C. at a temperature elevation rate of 20&#xb0; C./min and a strength of 12.0 cN/dtex or more; and a process for production of the same. A liquid crystalline polyester fiber which is excellent in abrasion resistance and lengthwise uniformity and is improved in weavability and quality of fabric and which is characterized by a small single-fiber fineness can be efficiently produced without impairing the characteristics inherent in fabric made of liquid crystalline polyester fiber produced by solid phase polymerization, namely, high strength, high elastic modulus and excellent thermal resistance.

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Mishima, Japan

Hiroo Katsuta