Abstract: A melt-spun highly oriented and crystalline thermoplastic filament or fiber having a tenacity of at least about 10 g/d, an elongation less than about 15%, and a modulus of at least about 130 g/d. A method of making highly oriented and crystalline thermoplastic filaments has been developed that comprises extruding a thermoplastic polymer to form at least one molten filament. The at least one molten filament is introduced into a horizontal liquid isothermal bath. The bath is maintained at a temperature between the glass transition temperature and the melting temperature of the thermoplastic polymer. The bath increases the tension along the molten filament to form at least one partially oriented and low crystalline filament. The partially oriented filament is drawn to form the highly oriented and crystalline filament.

Abstract: A melt-spun highly oriented and crystalline thermoplastic filament or fiber having a tenacity of at least about 10 g/d, an elongation less than about 15-%, and a modulus of at least about 130 g/d. A method of making highly oriented and crystalline thermoplastic filaments has been developed that comprises extruding a thermoplastic polymer to form at least one molten filament. The at least one molten filament is introduced into a horizontal liquid isothermal bath. The bath is maintained at a temperature between the glass transition temperature and the melting temperature of the thermoplastic polymer. The bath increases the tension along the molten filament to form at least one partially oriented and low crystalline filament. The partially oriented filament is drawn to form the highly oriented and crystalline filament.

Abstract: A melt-spun highly oriented and crystalline thermoplastic filament or fiber having a tenacity of at least about 10 g/d, an elongation less than about 15-%, and a modulus of at least about 130 g/d. A method of making highly oriented and crystalline thermoplastic filaments has been developed that comprises extruding a thermoplastic polymer to form at least one molten filament. The at least one molten filament is introduced into a horizontal liquid isothermal bath. The bath is maintained at a temperature between the glass transition temperature and the melting temperature of the thermoplastic polymer. The bath increases the tension along the molten filament to form at least one partially oriented and low crystalline filament. The partially oriented filament is drawn to form the highly oriented and crystalline filament.

Abstract: Ultra-oriented, crystalline synthetic filaments with a combination of high tenacity, high dimensional stability, high modulus, and a high fraction of taut-tie molecular phase are produced by extruding a fiber-forming synthetic polymer melt into a liquid isothermal bath, withdrawing the filaments from the bath and then post-treating them at a very low draw ratio. The bath is preferably maintained at a temperature of at least 30.degree. C. above the glass transition temperature of the polymer to enhance the orientation and promote the formation of stable extended chains. Polymer filaments so produced are characterized in that they have ultra-high birefringence, high tenacity and modulus, a high dimensional stability, and a high fraction of taut-tie molecular phase.

Abstract: Ultra-oriented, crystalline synthetic filaments with high tenacity are produced by extrusion of a fiber-forming synthetic polymer melt into a liquid isothermal bath maintained at a temperature of at least 30.degree. C. above the glass transition temperature of the polymer, withdrawing the filaments from the bath and then winding up the filaments. Polymer filaments so produced are characterized in that the ratio of the crystalline orientation factor (f.sub.c) to the amorphous orientation factor (f.sub.a) is 1.2 or less, and are further characterized in that the percent crystallinity is less than 40. The filaments also have a fine crystal size. The crystal size is less than 40 .ANG. in the 100 and 105 planes and less than 30 .ANG. in the 010 plane.

Abstract: Ultra-oriented, crystalline synthetic filaments with high tenacity are produced by extrusion of a fiber-forming synthetic polymer melt into a liquid isothermal bath maintained at a temperature of at least 30.degree. C. above the glass transition temperature of the polymer, withdrawing the filaments from the bath and then winding up the filaments. Polyethylene terephthalate filaments so produced at 3000-5000 m/min exhibit a crystalline structure and possess birefringence of 0.20-0.22, tenacity of 7-9 g/d, break elongation of 14-30% and boil-off shrinkage of 5-10%.

Abstract: The invention provides improved thermoplastic high strength, highly oriented fibers and a process for producing the fibers by melt spinning a thermoplastic polymer to form a threadline, preferably passing the threadline through a thermal conditioning zone and then quenching the threadline. The quenched threadline is passed through a hydraulic drag bath maintained at a temperature of greater than the glass transition temperature of the polymer which substantially increases the threadline stress and results in drawing of the threadline. The threadline is withdrawn from the drag bath at a withdrawal rate of at least 3,000 meters per minute.

Abstract: Ultra-oriented, crystalline synthetic filaments with high tenacity are produced by extrusion of a fiber-forming synthetic polymer melt into a liquid isothermal bath maintained at a temperature of at least 30.degree. C. above the glass transition temperature of the polymer, withdrawing the filaments from the bath and then winding up the filaments. Polyethylene terephthalate filaments so produced at 3000-5000 m/min exhibit a crystalline structure and possess birefringence of 0.20-0.22, tenacity of 7-9 g/d, break elongation of 14%-30% and boil-off shrinkage of 5%-10%.

Abstract: The high speed melt spinning of synthetic polymer fibers is provided with on-line zone heating and cooling by which the strand emerging from the spinneret is initially cooled to an optimum temperature above the glass transition point of the polymer, the maintained near that temperature for a period of time to promote development of desirable fiber properties such as crystallization and crystal orientation, and then finally cooled below the solidification point for take up.

Abstract: Ultra-oriented, crystalline synthetic filaments with high tenacity are produced by extrusion of a fiber-forming synthetic polymer melt into a liquid isothermal bath maintained at a temperature of at least 30.degree. C. above the glass transition temperature of the polymer, withdrawing the filaments from the bath and then winding up the filaments. Polymer filaments so produced are characterized in that the ratio of the crystalline orientation factor (f.sub.c) to the amorphous orientation factor (f.sub.a) is 1.2 or less, and are further characterized in that the percent crystallinity is less than 40. The filaments also have a fine crystal size. The crystal size is less than 40 .ANG. in the 100 and 105 planes and less than 30 .ANG. in the 010 plane.