Abstract: It is an object of the present invention to overcome the problem of fibrillation which is a drawback found in solvent-spun regenerated cellulosic fibers and to thereby provide high-quality regenerated cellulosic fibers. The regenerated cellulosic fibers are produced by the use of a spinning dope of cellulose dissolved in a solvent containing N-methylmorpholine N-oxide under the conditions that the average degree of polymerization of cellulose contained in the spinning dope is held to 400 or lower and 5% to 30% by weight of the cellulose is adjusted to a degree of polymerization of 500 or higher. Thus a pseudo-liquid-crystalline phenomenon can be allowed to occur in the stretched filaments during spinning, so that the resulting regenerated cellulosic fibers have improved resistance to fibrillation as well as improved dyeability and feeling.

Abstract: It is an object of the present invention to overcome the problem of fibrillation which is a drawback found in solvent-spun regenerated cellulosic fibers and to thereby provide high-quality regenerated cellulosic fibers. The regenerated cellulosic fibers are produced by the use of a spinning dope of cellulose dissolved in a solvent containing N-methylmorpholine N-oxide under the conditions that the average degree of polymerization of cellulose contained in the spinning dope is held to 400 or lower and 5% to 30% by weight of the cellulose is adjusted to a degree of polymerization of 500 or higher. Thus a pseudo-liquid-crystalline phenomenon can be allowed to occur in the stretched filaments during spinning, so that the resulting regenerated cellulosic fibers have improved resistance to fibrillation as well as improved dyeability and feeling.

Abstract: A tire includes polybenzazole (PBZ) fibers, preferably either polybenzoxazole (PBO) or polybenzothiazole (PBT) fibers which are liquid-crystalline. The PBZ fibers can be incorporated into either the carcass of the tire, the reinforcing belts, or both. Preferably the PBZ fibers have a) a tensile strength of at least 4.0 GPa; b) a tensile modulus of at least 140 GPa; and c) an average void diameter of 25 .ANG. or less.

Abstract: There is provided a cord of twisted polybenzazole fibers, which has a tenacity of 35 g/d or higher and an elastic modulus of 800 g/d or higher. The cord has not only remarkably improved fatigue resistance but also excellent mechanical characteristics at a high level that has not been achieved so far. Therefore, it can attain the weight reduction of composite materials, particularly in the field of reinforced rubber materials, and can also make a great contribution to the energy saving.

Abstract: Crimped polybenzazole staple fibers which satisfy the following specifications at the same time:(1) 2.ltoreq.number of crimps (number/inch).ltoreq.40(2) 2.ltoreq.crimp index (%).ltoreq.30(3) 0.3.ltoreq.crimp index/number of crimps.ltoreq.3.0; methods for manufacturing crimped polybenzazole staple fibers; and the rotary cutter therefor. The crimped polybenzazole staple fibers of the present invention are superior in crimp property and are useful for manufacturing spun yarn and unwoven fabric. According to the method of the present invention, crimped polybenzazole staple fibers superior in spinnability can be manufactured with ease. In addition, the cutting blade of the present invention stands a long time use for manufacturing staple fibers from a continuous filaments tow of high tenacity fibers.

Abstract: A continuous process for preparing nonwoven fabrics of polybenzazole filaments, which comprises spinning at least two polybenzazole dope filaments simultaneously, and intermingling and depositing the filaments on a substantially planar collecting surface, thereby forming a nonwoven fabric.

Abstract: In a process for preparing polybenzoxazole or polybenzothiazole filaments by extruding a polybenzoxazole or polybenzothiazole dope, drawing the dope filament across an air gap, and coagulating the dope filament; the number of filament breaks can be reduced by placing a stress isolation device after extruding but before coagulating the filament.

Abstract: Crimped polybenzazole staple fibers which satisfy the following specifications at the same time:(1) 2.ltoreq.number of crimps (number/inch).ltoreq.40(2) 2.ltoreq.crimp index (%).ltoreq.30(3) 0.3.ltoreq.crimp index/number of crimps.ltoreq.3.0; methods for manufacturing crimped polybenzazole staple fibers; and the rotary cutter therefor. The crimped polybenzazole staple fibers of the present invention are superior in crimp property and are useful for manufacturing spun yarn and unwoven fabric. According to the method of the present invention, crimped polybenzazole staple fibers superior in spinnability can be manufactured with ease. In addition, the cutting blade of the present invention stands a long time use for manufacturing staple fibers from a continuous filaments tow of high tenacity fibers.

Abstract: This invention aims at improvement of heat-treatment technology for manufacture of large amounts of polybenzazole fibers. The fibers are heat treated using steam as the heat treatment gas in a device that provides for a rapid, cocurrent, countercurrent or both cocurrent and countercurrent flow of steam.

Abstract: A rubber composite comprising polyester fibers as the reinforcing material, wherein a compound having at least one cyclic imino ether group of a specific structure in its molecule is incorporated in a rubber composite except for adhesive-treated polyester cords.

Abstract: Polyester fibers having high tenacity and high modulus can be produced practically and economically by melt-spinning a copolyester at a take-up speed of 3,000 meters/min. or more. The copolyester comprises at least 60 mol % of ethylene terephthalate units, has a persistence length of 15 angstroms or more and does not show a liquid crystalline nature in the molten state.

Abstract: A polyester fiber having excellent thermal dimensional stability and chemical stability as well as high tenacity, which is a drawn yarn produced by melt-spinning a polyester comprising predominantly polyethylene terephthalate, solidification the spun yarn and then drawing the yarn under specified conditions and has specified properties such as intrinsic viscosity, diethylene glycol content, carboxyl group content, birefringence, yarn tenacity and difference of average birefringence between surface and center of monofilament, and further low dry heat shrink and work loss when heat-treated, said polyester fiber being useful as a reinforcement for rubber goods, specifically as a tire cord, and processes for the production of the polyester fiber.

Abstract: A high strength polyester fibrous product reduced in heat build-up and improved in durability and useful for reinforcing rubber materials, which can be prepared by twisting drawn yarns obtained by (1) melt spinning a polymeric composition comprising polyethylene terephthalate as the main polymer component and at least one methylene group-containing polyester in such an amount that the proportion of the total number of methylene groups to the total number of terephthalic acid residues in all the polymer components is more than 2.0 and less than 2.