A method of making a polyhydroxyalkanoate yarn comprising a polyhydroxyalkanoate fiber is disclosed. The method comprises extruding a polymer melt comprising a polyhydroxyalkanoate composition comprising a polyhydroxyalkanoate through a spinneret, withdrawing a fiber from the spinneret, quenching the fiber, and collecting the fiber on a winding roller. The yarn exhibits an elongation at break of 50% or more to 1000% or less and a tenacity of 0.1 g/d or more to 4 g/d or less. A polyhydroxyalkanoate yarn comprising a polyhydroxyalkanoate fiber is also disclosed.

A method of manufacturing multi-ply separable textured yarn, the method comprising, passing a multi-ply separable interlaced filament yarn through a texturizing unit to form a multi-ply separable draw textured yarn, wherein the multi-ply separable interlaced filament yarn is separable in to at least two separable interlaced filament yarn, wherein the interlacing 10 of the filaments within each separable interlaced filament yarn is retained during further processing of the yarn to fabric and in the fabric.

A method of manufacturing multi-ply separable textured yarn, the method comprising, passing a multi-ply separable interlaced filament yarn through a texturizing unit to form a multi-ply separable draw textured yarn, wherein the multi-ply separable interlaced filament yarn is separable in to at least two separable interlaced filament yarn, wherein the interlacing 10 of the filaments within each separable interlaced filament yarn is retained during further processing of the yarn to fabric and in the fabric.

The present disclosure pertains to: polyamide fibers for an airbag which are characterized in that the fiber size thereof is 200-800 dtex, inclusive, and the stress retention rate thereof when obtained using a prescribed procedure is at least 3.0%; and a method for producing said polyamide fibers for an airbag, the method being characterized in that during the thermosetting step and the relaxing step thereof, the contact time between thread and a roller which is at least 190 C. is at least 30 msec and less than 110 msec, the temperature of the thermosetting roller is 190-205 C., inclusive, the temperature of the relaxing roller is greater than 100 C. and less than 190 C., and the speed ratio of the relaxing roller to the thermosetting roller satisfies this equation: 1.00<relaxing roller speed/thermosetting roller speed<1.10.

Provided is a liquid crystalline polyester fiber capable of achieving improved weatherability without kneading a UV absorber into the fiber or attaching a weatherable UV absorber after fiber spinning. The liquid crystalline polyester is a fiber that consists essentially only of a liquid crystalline polyester, in which the amount of UV absorber used is 5 mass % or less, and the strength retention in the weather fastness test with xenon arc lamp light in accordance with JIS L 0891 is 60% or more.

Provided is a liquid crystalline polyester fiber capable of achieving improved weatherability without kneading a UV absorber into the fiber or attaching a weatherable UV absorber after fiber spinning. The liquid crystalline polyester is a fiber that consists essentially only of a liquid crystalline polyester, in which the amount of UV absorber used is 5 mass % or less, and the strength retention in the weather fastness test with xenon arc lamp light in accordance with JIS L 0891 is 60% or more.