A method for providing a multifilament bundle of melt spun polymer filaments that includes providing a spinning device including at least M extruders for melting M polymers, M groups of spinning stations, each group comprising N spinning stations, each spinning station comprising a spin pack coupled to a spin pump which receives molten polymer from one of the M extruders and spins a strand of filaments by pushing said polymer through the coupled spin pack, and N transformation stations for bundling M strands of filaments. The method further includes spinning N*M strands of filaments from the spinning stations at a given spin pump output and bundling the strands into N multifilament bundles via the N transformation stations whereby the spin pump outputs are varied over time.

Fibers made a polyethylene composition, and method of making the same. The polyethylene composition comprises less than or equal to 100 percent by weight of the units derived from ethylene and less than 20 percent by weight of units derived from one or more -olefin comonomers; wherein said polyethylene composition has a density in the range of 0.930 to 0.960 g/cm.sup.3, a molecular weight distribution (Mw/Mn) in the range of 1.70 to 3.5, a melt index (I.sub.2) in the range of 1 to 300 g/10 minutes, a molecular weight distribution (Mz/Mw) in the range of less than 2.5, a shear viscosity in the range of 20 to 250 Pascal-s at 3000 s.sup.1 shear rate measured at 190 C., vinyl unsaturation of less than 0.1 vinyls per one thousand carbon atoms present in the backbone of said composition; and wherein the fiber is a monocomponent meltspun fiber.

A method for providing a multifilament bundle of melt spun polymer filaments that includes providing a spinning device including at least M extruders for melting M polymers, M groups of spinning stations, each group comprising N spinning stations, each spinning station comprising a spin pack coupled to a spin pump which receives molten polymer from one of the M extruders and spins a strand of filaments by pushing said polymer through the coupled spin pack, and N transformation stations for bundling M strands of filaments. The method further includes spinning N*M strands of filaments from the spinning stations at a given spin pump output and bundling the strands into N multifilament bundles via the N transformation stations whereby the spin pump outputs are varied over time.

A method for providing a multifilament bundle of melt spun polymer filaments that includes providing a spinning device including at least M extruders for melting M polymers, M groups of spinning stations, each group comprising N spinning stations, each spinning station comprising a spin pack coupled to a spin pump which receives molten polymer from one of the M extruders and spins a strand of filaments by pushing said polymer through the coupled spin pack, and N transformation stations for bundling M strands of filaments. The method further includes spinning N*M strands of filaments from the spinning stations at a given spin pump output and bundling the strands into N multifilament bundles via the N transformation stations whereby the spin pump outputs are varied over time.

The present disclosure provides a photochromic thermal insulation fiber including a core layer and a sheath layer covering the core layer. The core layer includes about 99 parts by weight to 100 parts by weight of polypropylene and about 0.4 parts by weight to 0.6 parts by weight of a photochromic dye. The sheath layer includes about 98 parts by weight to 99 parts by weight of nylon and about 1 part by weight to 2 parts by weight of a near-infrared reflecting dye.

The present disclosure provides a photochromic thermal insulation fiber including a core layer and a sheath layer covering the core layer. The core layer includes about 99 parts by weight to 100 parts by weight of polypropylene and about 0.4 parts by weight to 0.6 parts by weight of a photochromic dye. The sheath layer includes about 98 parts by weight to 99 parts by weight of nylon and about 1 part by weight to 2 parts by weight of a near-infrared reflecting dye.

The instant invention discloses fibers. The fibers according to the instant invention comprise a polyethylene composition comprising: (a) less than or equal to 100 percent by weight of the units derived from ethylene; and (b) less than 20 percent by weight of units derived from one or more -olefin comonomers; wherein the polyethylene composition has a density in the range of 0.920 to 0.970 g/cm.sup.3, a molecular weight distribution (M.sub.w/M.sub.n) in the range of 1.70 to 3.5, a melt index (I.sub.2) in the range of 0.2 to 1000 g/10 minutes, a molecular weight distribution (M.sub.z/M.sub.w) in the range of less than 2.5, vinyl unsaturation of less than 0.1 vinyls per one thousand carbon atoms present in the backbone of the composition.

The invention is: a fiber produced by forming a fiber using pellets, and annealing the fiber at 150 to 220 C., the pellets being formed of a resin powder of a cycloolefin polymer, the resin powder having a loose bulk density of 0.3 to 0.6 g/cc when measured using 100 cc of the resin powder: a method for producing the fiber. The invention provides a method for producing a cycloolefin polymer fiber that exhibits good productivity and strength during spinning, and a low thermal shrinkage ratio.

Provided is a thermal molding method for producing a thermally molded article having excellent abrasion resistance at its melt-fused part. Polyamide 6 and a copolyester are prepared separately. The copolyester contains terephthalic acid, ethylene glycol, and 1,4-butanediol as copolymerization units. The copolyester may further contain -caprolactone and/or diethylene glycol as a copolymerization unit. A multifilament yarn in which core-sheath type composite filaments each containing a core component and a sheath component at a ratio of 1 to 4:1 by mass are bundled is produced by a composite melt-spinning method using the polyamide 6 as the core component and the copolyester as the sheath component. Using the multifilament yarn, a product of filaments is produced by weaving, knitting, knitting and braiding, or braiding. The product of filaments is heated to melt the copolyester and fuse the core-sheath type composite filaments to each other while retaining the initial filament form of the polyamide 6, thus thermally molding the product of filaments.

Provided is a thermal molding method for producing a thermally molded article having excellent abrasion resistance at its melt-fused part. Polyamide 6 and a copolyester are prepared separately. The copolyester contains terephthalic acid, ethylene glycol, and 1,4-butanediol as copolymerization units. The copolyester may further contain -caprolactone and/or diethylene glycol as a copolymerization unit. A multifilament yarn in which core-sheath type composite filaments each containing a core component and a sheath component at a ratio of 1 to 4:1 by mass are bundled is produced by a composite melt-spinning method using the polyamide 6 as the core component and the copolyester as the sheath component. Using the multifilament yarn, a product of filaments is produced by weaving, knitting, knitting and braiding, or braiding. The product of filaments is heated to melt the copolyester and fuse the core-sheath type composite filaments to each other while retaining the initial filament form of the polyamide 6, thus thermally molding the product of filaments.