Abstract: A process for the production of partially oriented polypropylene fibers from syndiotactic polypropylene. Syndiotactic polypropylene is heated to a molten state and extruded to form a fiber preform. The fiber preform is spun at a forward spinning speed within the range of about 700-3500 meters per minute to produce a partially oriented fiber. The partially oriented fiber is wound without further substantial orientation of the fiber at a draw ratio of less than 1.5. By operating at a forward spinning speed of about 700 meters per minute or more, the partially oriented fiber has a greater tenacity than would be observed for a fiber formed from a corresponding spun isotactic polypropylene. The fiber preform is spun at a forward spinning speed of at least 100 meters per minute to provide a tenacity on the order of about 2 grams per denier or more. The fiber preform may be spun at a forward spinning speed of at least 1500 meters per minute to provide a tenacity of about 3 grams per denier.

Abstract: Bicomponent fibers of syndiotactic polypropylene and ethylene-propylene random copolymer, can be prepared. The bicomponent fibers may exhibit self-crimp properties and high shrinkage characteristics.

Abstract: A process for the production of partially oriented polypropylene fibers from syndiotactic polypropylene. Syndiotactic polypropylene is heated to a molten state and extruded to form a fiber preform. The fiber preform is spun at a forward spinning speed within the range of about 700–3500 meters per minute to produce a partially oriented fiber. The partially oriented fiber is wound without further substantial orientation of the fiber at a draw ratio of less than 1.5. By operating at a forward spinning speed of about 700 meters per minute or more, the partially oriented fiber has a greater tenacity than would be observed for a fiber formed from a corresponding spun isotactic polypropylene. The fiber preform is spun at a forward spinning speed of at least 100 meters per minute to provide a tenacity on the order of about 2 grams per denier or more. The fiber preform may be spun at a forward spinning speed of at least 1500 meters per minute to provide a tenacity of about 3 grams per denier.

Abstract: The present invention relates to fibrillation resistant polypropylene tape formed from the polymerization of propylene utilizing isospecific metallocene catalysts. The resulting polymerized isotactic polypropylene is heated, extruded and withdrawn as a film or sheet. The sheet is then slit longitudinally into tape segments and drawn in the longitudinal direction to a draw ratio of at least about 4.5:1 to produce an oriented tape. It has been found that these polypropylene tapes have improved resistance to fibrillation than those polypropylene tapes produced using Ziegler-Natta catalyst drawn at the same draw ratios.

Abstract: Bicomponent fibers of syndiotactic polypropylene and ethylene-propylene random copolymer, can be prepared. The bicomponent fibers may exhibit self-crimp properties and high shrinkage characteristics.

Abstract: A method for the production of polypropylene fibers from a propylene polymer including isotactic polypropylene produced by the polymerization of propylene in the presence of an isospecific metallocene catalyst. The polymer is heated to a molten state and extruded to form a fiber preform at a temperature within the range of about 170°-210° C. The fiber preform is spun at a spinning speed of at least 200 meters per minute and quenched at a heat transfer rate of no more than 12 joules per second fiber. The spun fiber is then subjected to a winding operation. The fiber may be drawn subsequent to the quenching operation and prior to winding. The cooled fiber preform may be drawn to produce a fiber at a draw ratio within the range of about 1.5-4.0 with shrinkage of the fiber over the range of the draw ratio at a variance of ±25% of the median of the shrinkage factor over the draw ratio.

Abstract: Bicomponent fibers of isotactic polypropylene and syndiotactic polypropylene, methods of making such fibers and products made thereof are disclosed. Embodiments of the bicomponent fibers can exhibit self-crimp properties and high shrinkage characteristics.

Abstract: The present invention relates to a process for making polymer tapes utilizing metallocene catalysts. An isotactic propylene polymer is prepared by polymerizing propylene in the presence of an isospecific metallocene catalyst. The resulting polypropylene is heated, extruded and withdrawn as a sheet. The sheet is then slit longitudinally into tape segments and drawn in the longitudinal direction to a draw ratio of at least about 4.5:1 to produce an oriented tape. It has been found that these polypropylene tapes have different characteristics than those polypropylene tapes produced using Ziegler-Natta catalyst drawn at the same draw ratios.

Abstract: A method for the production of polypropylene fibers from a propylene polymer comprising isotactic polypropylene produced by the polymerization of propylene in the presence of an isospecific metallocene catalyst. The polymer is heated to a molten state and extruded to form a fiber preform at a temperature within the range of about 170°-21° C. The fiber preform is spun at a spinning speed of at least 200 meters per minute and quenched at a heat transfer rate of no more than 12 joules per second per fiber. The spun fiber is then subjected to a winding operation. The fiber may be drawn subsequent to the quenching operation and prior to winding. The cooled fiber preform may be drawn to produce a fiber at a draw ratio within the range of about 1.5-4.0 with shrinkage of the fiber over the range of the draw ratio at a variance of ±25% of the median of the shrinkage factor over the draw ratio.

Abstract: The present invention relates to a process for making polymer tapes utilizing metallocene catalysts. An isotactic propylene polymer is prepared by polymerizing propylene in the presence of an isospecific metallocene catalyst. The resulting polypropylene is heated, extruded and withdrawn as a sheet. The sheet is then slit longitudinally into tape segments and drawn in the longitudinal direction to a draw ratio of at least about 4.5:1 to produce an oriented tape. It has been found that these polypropylene tapes have different characteristics than those polypropylene tapes produced using Ziegler-Natta catalyst drawn at the same draw ratios.

Abstract: A process for the production of partially oriented polypropylene fibers from syndiotactic polypropylene. Syndiotactic polypropylene is heated to a molten state and extruded to form a fiber preform. The fiber preform is spun at a forward spinning speed within the range of about 700-3500 meters per minute to produce a partially oriented fiber. The partially oriented fiber is wound without further substantial orientation of the fiber at a draw ratio of less than 1.5. By operating at a forward spinning speed of about 700 meters per minute or more, the partially oriented fiber has a greater tenacity than would be observed for a fiber formed from a corresponding spun isotactic polypropylene. The fiber preform is spun at a forward spinning speed of at least 100 meters per minute to provide a tenacity on the order of about 2 grams per denier or more. The fiber preform may be spun at a forward spinning speed of at least 1500 meters per minute to provide a tenacity of about 3 grams per denier.

Abstract: The present invention relates to a method for the production of polypropylene fibers resulting in improved shrinkage percentages and to polypropylene fibers themselves having improved shrinkage percentages. The method includes providing a polypropylene polymer with a melt flow index of no more than about 25 grams per 10 minutes. This polymer should include isotactic polypropylene produced by the polymerization of propylene in the presence of an isospecific metallocene catalyst. The polymer is then heated to a molten state and extruded to form a fiber preform. The preform is spun and subsequently drawn at a take-away speed and a drawing speed providing a draw ratio of no more than about 3, and more preferably no more than about 2.5, to produce a continuous polypropylene fiber.

Abstract: The present invention relates to a method for the production of polypropylene fibers resulting in improved shrinkage percentages and to polypropylene fibers themselves having improved shrinkage percentages. The method includes providing a polypropylene polymer with a melt flow index of no more than about 25 grams per 10 minutes. This polymer should include isotactic polypropylene produced by the polymerization of propylene in the presence of an isospecific metallocene catalyst. The polymer is then heated to a molten state and extruded to form a fiber preform. The preform is spun and subsequently drawn at a take-away speed and a drawing speed providing a draw ratio of no more than about 3, and more preferably no more than about 2.5, to produce a continuous polypropylene fiber.

Abstract: The present invention relates to a method for the production of polypropylene fibers resulting in improved shrinkage percentages and to polypropylene fibers themselves having improved shrinkage percentages. The method includes providing a polypropylene polymer with a melt flow index of no more than about 25 grams per 10 minutes. This polymer should include isotactic polypropylene produced by the polymerization of propylene in the presence of an isospecific metallocene catalyst. The polymer is then heated to a molten state and extruded to form a fiber preform. The preform is spun and subsequently drawn at a take-away speed and a drawing speed providing a draw ratio of no more than about 3, and more preferably no more than about 2.5, to produce a continuous polypropylene fiber.

Abstract: A polymer blend, fibers manufactured from the blend and method of producing the fibers is disclosed. The polymer blend includes from 92 wt % to 98.5 wt % of a base polypropylene having a melt flow rate of less than 20 g/10 min, and a maximum draw ratio D, a Crimp Stability of CS, when drawn into filaments at 1000 m/sec, and from 8 wt % to 1.5 wt % of an amorphous polystyrene having a melt flow rate of less than 15 g/10 min. The polymer blend is drawable at greater than 800 m/sec to produce filaments having a maximum draw ratio of D2, the ratio of D2: D1, being greater than 1.15:1 and a Crimp Stability of CS2, the ratio of CS2: CS1 being greater than 1.45. Preferably, the base polypropylene has a melt flow rate of between 8 and 15 g/10 min. In one embodiment, the amorphous polystyrene is characterized by a melt flow between 2 and 15 g/10 min.

Abstract: A process for the production and treatment of a stereoregular polypropylene, such as isotactic polypropylene in which a polymerization reactor is operated under conditions to react propylene supplied to the reactor to produce a stereoregular propylene polymer fluff. A product stream containing the fluff and unreacted propylene is withdrawn from the reactor and at least a portion of the unreacted propylene is separated from the product stream. The propylene polymer fluff is heated to a temperature sufficient to melt the propylene polymer, and a lactone is incorporated into the propylene polymer. The lactone is a 5,7 dialkyl-3-(2,3 dialkyl phenyl)-3H-benzofuran-2-one, in which the 5,7 and 2,3 substituents are of relatively low molecular weights. The phenyl alkyl substituents, each contain 1 or 2 carbon atoms, and the 5,7 alkyl substituents each contain from 2 to 5 carbon atoms.