Toyo Boseki Kabushiki Kaisha

Toyo Boseki Kabushiki Kaisha (Toyobo Co., Ltd.)

Kazuo Kurita

Hideaki Ishihara

Susumu Tate

Yoshihiko Teramoto

Toshihiko Ohta

Fujio Okada

Masahiro Hayashi

Youichi Watanabe

Akira Chiba

Wataru Yoshikawa

A process for producing polyester fibers having excellent tensile properties, particularly suitable as reinforcement material for tires, belts, etc., involves melt-spinning an ethylene terephthalate polyester to form highly oriented low crystalline polyester filaments which, at the state of being taken-up and prior to being drawn, having birefringence (.DELTA.n) and specific gravity (SG) within the below indicated ranges (a) and (b), and then, without winding-up, subjecting the said filaments immediately to drawing and heat treatment between the first godet rolls and second godet rolls under a draw ratio (DR) defined by the following formulas:

Process for producing polyester fibers

Process for producing polyester fibers of high tenacity and high modulus, by melt-spinning a polyester having an intrinsic viscosity of not lower than 0.3, to obtain extruded filaments of low orientation having a birefringence not higher than 10.0.times.10.sup.-3, post-polymerizing the filaments in a heating medium, and subjecting the filaments to multi-stage drawing in at least two stages.

A polyamide fiber excellent in strength, which comprises at least one of polycapramide, polyhexamethylene adipamide and polytetramethylene adipamide in an amount of not less than 60% by weight on the basis of the polyamide fiber and which is characterized by having a relative viscosity of not less than 2.3 and less than 3.5 (measured on a 96% by weight sulfuric acid solution having a polyamide concentration of 10 mg/ml at 20.degree. C.), an index of birefringence (.DELTA.n) (measured after 24 hours under the conditions of 30.degree. C. and 80% relative humidity) of not less than 55.times.10.sup.-3 and a tenacity of not less than 12.0 g/d. The method of preparing the noted polyamide fibers includes spinning of the polyamide to produce filaments, cooling the filaments, taking up the filaments to make an index of birefringence of 13.times.10.sup.-3 or less and drawing the filaments so taken up. The drawing includes transferring the filaments onto a first supply roller and then a second supply roller with the application of a pre-draft of less than 20% between the first and second supply rollers, transferring the resultant pre-drafted filaments onto a first draw roller and thereafter onto a second draw roller. Between the draw rollers a heating zone is maintained with a temperature gradient from low to high. The first draw roller is kept at a temperature of not lower than 100.degree. C. and the second draw roller is kept at a temperature of not lower than 200.degree. C. Also, super-heated steam from a jet nozzle at a temperature of not lower than 200.degree. C. is applied to the filaments transferred onto the first draw roller.

Process for preparing polyamide fibers having improved properties

Polyester fibers having both a high strength and a high modulus prepared from ethylene terephthalate polyester, and having an intrinsic viscosity of not less than 1.0 and an initial tensile modulus is not less than 130 g/d, said intrinsic viscosity being determined in a mixed solvent of p-chlorophenol and tetrachloro ethane (3:1) at 30.degree. C. Processes for producing the fibers are also disclosed.

Polyester fibers having high strength and high modulus and process for

A polyamide fiber excellent in strength, which comprises at least one of polycapramide, polyhexamethylene adipamide and polytetramethylene adipamide in an amount of not less than 60% by weight on the basis of the polyamide fiber and which is characterized by having a relative viscosity of not less than 2.3 and less than 3.5 (measured on a 96% by weight sulfuric acid solution having a polyamide concentration of 10 mg/ml at 20.degree. C.), an index of birefringence (.DELTA.n) (measured after 24 hours under the conditions of 30.degree. C. and 80% relative humidity) of not less than 55.times.10.sup.-3 and a tenacity of not less than 12.0 g/d, the index of birefringence in section satisfying the following relationship:

Polyamide fibers having improved properties, and their production

A process for the manufacture of polyamide fibers including melt spinning a polyamide having a relative viscosity of not less than 3.50 under conditions satisfying the following relationships:

Process for the manufacture of polyamide fibers

A polyamide fiber excellent in strength, which is characterized by being made of a polyamide having a relative viscosity of not less than 3.5 (measured on a 96% by weight sulfuric acid solution having a polyamide concentration of 10 mg/ml at 20.degree. C.), showing an index of birefringence (.DELTA.n) of not less than 50.times.10.sup.-3 and having the following relationship between the break strength and the break elongation:

Polyamide fibers having improved properties and their production

A polyamide fiber excellent in strength, which is characterized by having a relative viscosity of not less than 2.3 (measured on a 96% by weight sulfuric acid solution having a polyamide concentration of 10 mg/ml at 20.degree. C.), having an index of birefringence in section which satisfies the following relationship:

Growing community of inventors

Otsu, Japan

Kazuo Kurita