Improvements in or relating to the Crimping of Continuous Filaments

1,172,361. Crimping filaments. IMPERIAL CHEMICAL INDUSTRIES Ltd. 9 March, 1967 [22 March, 1966], No. 12574/66. Headings D1F and D1W. Continuous filaments are crimped by heating them while they are travelling towards a first assembly of denticulated members, passing them through the first assembly and through a second assembly of denticulated members which impart a crimp of different characteristic from that imparted by the first assembly. As described, the two assemblies comprise two pairs of gear wheels disposed in a draw frame between a heated snubbing pin and the draw rolls. Alternatively, the draw rolls may be replaced by the second pair of gear wheels. The filaments may be cooled by an air jet between the two pairs which, to produce crimps of different characteristics, may differ in diameter, speed of revolution, or number of teeth per inch or may be disposed in different planes. Some of the filaments may have one crimp frequency, others may have a second crimp frequency, while the majority of the filaments may have the two frequencies superimposed. The second crimping may produce an irregularity of crimp. The speed of the gears wheels may be varied cyclically, or intermittently at random or regular intervals. The filaments may be fed to the draft frame directly from the extruder, be passed through an interlacing nozzle before wind-up, and be composed of nylon, a polyester or a polypropylene. Specification 1,172,362 is referred to.