Abstract: A melt spinning process and the nylon hollow filaments and yarns made by such process which includes extruding molten nylon polymer having a relative viscosity (RV) of at least about 50 and a melting point (T.sub.M) of about 210.degree. C. to about 310.degree. C. from a spinneret capillary orifice with multiple orifice segments providing a total extrusion area (EA) and an extrusion void area (EVA) such that the fractional extrusion void content, defined by the ratio [EVA/EA] is about 0.6 to about 0.95, and the extent of melt attenuation, defined by the ratio [EVA/(dpf).sub.S ], is about 0.05 to about 1.5, in which (dpf).sub.S is the spun denier per filament, the (dpf).sub.S being selected such that the denier per filament at 25% elongation (dpf).sub.25 is about 0.

Abstract: A post-coalescence melt-spinning process for preparing fine undrawn hollow polyester filaments having excellent mechanical quality and uniformity at high speeds (2-5 km/min) involving selection of polymer viscosity and spinning conditions, whereby the void content of the resulting new undrawn filaments is essentially maintained or increased on cold-drawing or hot-drawing with or without post heat treatment, and the new fine hollow polyester filaments obtained thereby.

Abstract: Hollow polyester undrawn filaments having excellent mechanical quality and uniformity are prepared by a simplified post-coalescence melt spinning process at speeds of e.g. 2-5 km/min by selection of polymer and spinning conditions whereby the void content of the undrawn filaments can be essentially maintained or even increased when drawn cold or hot, with or without post heat-treatment.

Abstract: Polyester filaments of high shrinkage and high shrinkage tension may be prepared by heat treatment of undrawn crystalline filaments of low shrinkage and shrinkage tension, and may be used for making polyester yarns of mixed shrinkage and bulky polyester yarns and fabrics therefrom.

Abstract: A post-coalescence melt-spinning process for preparing fine undrawn hollow polyester filaments having excellent mechanical quality and uniformity at high speeds (2-5 km/min) involving selection of polymer viscosity and spinning conditions, whereby the void content of the resulting new undrawn filaments is essentially maintained or increased on cold-drawing or hot-drawing with or without post heat treatment, and the new fine hollow polyester filaments obtained thereby.

Abstract: A melt spinning process and the nylon hollow filaments and yarns made by such process which includes extruding molten nylon polymer having a relative viscosity (RV) of at least about 50 and a melting point (T.sub.M) of about 210.degree. C. to about 310.degree. C. from a spinneret capillary orifice with multiple orifice segments providing a total extrusion area (EA) and an extrusion void area (EVA) such that the fractional extrusion void content, defined by the ratio [EVA/EA] is about 0.6 to about 0.95, and the extent of melt attenuation, defined by the ratio [EVA/(dpf).sub.S ], is about 0.05 to about 1.5, in which (dpf).sub.S is the spun denier per filament, the (dpf).sub.S being selected such that the denier per filament at 25% elongation (dpf).sub.25 is about 0.

Abstract: Flat continuous multifilament nylon apparel yarns suitable for critical dye applications and a process for making such yarns are provided. The process for making the yarns includes spinning nylon polymer with a relative viscosity between about 35 and about 80 and stabilizing to make a feed yarn. The withdrawal speed in spinning is sufficiently high that highly uniform feed yarns are provided. In the process, feed yarn is drawn and subsequently relaxed, preferably in the form of a warp of yarns, so that the resulting drawn yarns have properties suitable for use as flat yarns and have excellent dye uniformity with large molecule acid dyes.

Abstract: Polyester mixed fine filament yarns having excellent mechanical quality and uniformity, and preferably with a balance of good dyeability and shrinkage, are prepared by a simplified direct spin-orientation process by selection of polymer and spinning conditions.

Abstract: Polyester fine filaments having excellent mechanical quality and uniformity, and preferably with a balance of good dyeability and shrinkage, are prepared by a simplified direct spin-orientation process by selection of polymer viscosity and spinning conditions, followed by drawing and/or bulking.

Abstract: Polyester filaments of high shrinkage and high shrinkage tension may be prepared by heat treatment of undrawn crystalline filaments of low shrinkage and shrinkage tension, and may be used for making polyester yarns of mixed shrinkage and bulky polyester yarns and fabrics therefrom.

Abstract: Drawing, especially cold-drawing, or hot-drawing, or other heat-treatments, of spin-oriented crystalline polyester filaments, and particularly polyester feed yarns, that have been prepared by spinning at speeds of, e.g., 4 km/min, and have low shrinkage and no natural draw ratio in the conventional sense, provides useful technique for obtaining uniform filaments of desired denier and thereby provides improved flexibility to obtain filaments and yarns mixed with nylon filaments.

Abstract: Flat continuous multifilament nylon apparel yarns suitable for critical dye applications and a process for making such yarns are provided. The process for making the yarns includes spinning nylon polymer with a relative viscosity between about 35 and about 80 and stabilizing to make a feed yarn. The withdrawal speed in spinning is sufficiently high that highly uniform feed yarns are provided. In the process, feed yarn is drawn and subsequently relaxed, preferably in the form of a warp of yarns, so that the resulting drawn yarns have properties suitable for use as flat yarns and have excellent dye uniformity with large molecule acid dyes.

Abstract: Hollow polyester undrawn filaments having excellent mechanical quality and uniformity are prepared by a simplified post-coalescence melt spinning process at speeds of e.g. 2-5 km/min by selection of polymer and spinning conditions whereby the void content of the undrawn filaments can be essentially maintained or even increased when drawn cold or hot, with or without post heat-treatment.

Abstract: Polyester fine filaments having excellent mechanical quality and uniformity, and preferably with a balance of good dyeability and shrinkage, are prepared by a simplified direct spin-orientation process by selection of polymer viscosity and spinning conditions.

Abstract: Drawing, especially cold-drawing, or hot-drawing or other heat-treatments of spin-oriented crystalline polyester filaments, and particularly polyester feed yarns, that have been prepared by spinning at speeds of, e.g., 4 kg/min, and have low shrinkage and no natural draw ratio in the conventional sense, provides useful technique for obtaining uniform drawn filaments of desired denier and thereby provides improved flexibility to obtain filaments and yarns of various denier. The resulting uniform filaments have useful properties that are improved in certain respects.

Abstract: Polyester fine filaments having excellent mechanical quality and uniformity, and preferably with a balance of good dyeability and shrinkage, are prepared by a simplified direct spin-orientation process by selection of polymer viscosity and spinning conditions.

Abstract: Air-jet texturing with drawing, especially cold-drawing, or hot-drawing or other heat-treatments of spin-oriented crystalline polyester filaments, and particularly polyester feed yarns, that have been prepared by spinning at speeds of, e.g., 4 km/min, and have low shrinkage and no natural draw ratio in the conventional sense, provides useful technique for obtaining uniform drawn filaments of desired denier and thereby provides improved flexibility to obtain air-jet textured filaments and yarns of various denier. The resulting yarns have useful properties that are improved in certain respects.

Abstract: Drawing, especially cold-drawing, or hot-drawing or other heat-treatments of spin-oriented crystalline polyester filaments, and particularly polyester feed yarns, that have been prepared by spinning at speeds of, e.g., 4 kg/min, and have low shrinkage and no natural draw ratio in the conventional sense, provides useful technique for obtaining uniform drawn filaments of desired denier and thereby provides improved flexibility to obtain filaments and yarns of various denier. The resulting uniform filaments have useful properties that are improved in certain respects.

Abstract: A process of making mixed shrinkage yarn, including drawing, especially cold-drawing, or hot-drawing or other heat-treatments of spin-oriented crystalline polyester filaments, and particularly polyester feed yarns, that have been prepared by spinning at speeds of, e.g., 4 km/min, and have low shrinkage and no natural draw ratio in the conventional sense, that provides useful technique for obtaining uniform drawn filaments of desired denier and of differential shrinkage, and thereby provides improved flexibility to obtain filaments and yarns of mixed shrinkage.

Abstract: A process of making mixed filament yarns, involving drawing, especially cold-drawing, or hot-drawing, or other heat-treatments, of spin-oriented crystalline polyester filaments, and particularly polyester feed yarns, that have been prepared by spinning at speeds of, e.g., 4 km/min, and have low shrinkage and no natural draw ratio in the conventional sense, that provides useful technique for obtaining uniform filaments of desired denier and thereby provides improved flexibility to obtain filaments and yarns mixed with nylon filaments.