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: 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.