Abstract: An improved stuffer box used for crimping textile fibers, particularly fibrillated polyolefin films. The width of the stuffer box is related to the linear density of the fiber bundles to be crimped whereby there is one millemeter of width for each fiber bunder size in the range of from about 200 to about 750 denier. Pressure controlled hinged lid or fixed lid exit orifices may be employed. Also employed may be a distributing device for applying additive material to the textile fibers prior to crimping to enhance the crimping operation or to enhance the end use of the crimped fiber or both. Fibrillated polyolefin materials that are crimped in accordance with the invention are adapted for use as filter materials in smoking articles.

Abstract: A roller for use in fibrillating oriented films of polyolefin materials having a plurality of pins projecting from the surface of the roller. The pins are distributed in a plurality of rows spaced around the roller surface. The rows each contain about 25 to 34 pins per inch in a space-staggered relationship along two adjacent lines extending along the surface of the roller, either in a linear relationship inclined to a line parallel to the axis or rotation, or in a sinusoidal relationship with adjacent rows being in or out of phase. The roller is rotated and the film is advanced over the rotating roller surface for an arc length of contact of about 30 to 37 degrees to fibrillate the film. The ratio of the surface speed of the roller to the advancing film are controlled to a ratio between from about 1.8:1 to about 2.2:1.

Abstract: A polyolefin material having improved fibrillation properties, allowing one to achieve higher yield in cigarette filters made from the fibrillated material is provided. The material includes between about 70% and about 99% of at least one polypropylene homopolymer with a melt index of between about 1.2 to about 3.0 (measured according to ISO standard 1133 at 230.degree. C., 2.16 kgf) and a density of about 0.905 g/cc, and between about 1% and about 30% of at least one low density polyethylene homopolymer with a melt index of between about 0.9 and 3.0 (measured according to ISO standard 1133 at 190.degree. C., 2.16 kgf) and a density of about 0.921 g/cc.

Abstract: A method is provided for heating fibrillated polyolefin film prior to crimping, to improve the crimping, and thus the yield and variability as a filter, of the tow. The fibrillated tow is crimped while still hot from the heating step. The resulting fibers have more uniform crimping at higher levels than those not subject to heating.