Abstract: A process for the production of crimped filaments of semi-crystalline polyolefins or blends of polyolefins with other materials by melt drawing at 100 meters per minute or less, rapidly and asymmetrically cooling at least a portion of the filaments, forming the filaments into a tow and subjecting the tow to a heat treatment without drawing at at least 100.degree. C. and thereafter drawing the filaments in two stages, the last of which is at a temperature of at least 70.degree. C. With the practice of the process of this invention, there is provided a useful crimp of at least two crimps per centimeter which develops after the filaments are relaxed and subjected to a further heat treatment which may be applied either to the filaments or to products produced therefrom when in a relaxed state subsequent to drawing.

Abstract: Disclosed is a process for treating a travelling film made from a molecularly-orientable synthetic thermoplastic organic polymer, according to which the film while in an unoriented condition and a molten deformable state has at least one of its sides modified so as to have a homogeneous series of high frequency discrete protuberances or depressions. This is achieved by subjecting the film to the action of an appropriately contoured surface. The frequency is at least of the order of 100 per inch. The center line average height of the protuberances or depressions is preferably from 1 to 10 microns. The process is advantageously used for making, inter alia, weaving tapes, twine and fibrous materials.Also disclosed is apparatus for carrying out such a process. In a preferred form it comprises an extruder, a pair of nip rollers, at least one of which has an appropriately contoured surface, and a hot drawing means. Also disclosed are versions including slitting means and fibrillating means.