GB1155961A - Method and Apparatus for Production of Artificial Fibres by Fibrillating Oriented Films of Synthetic Polymeric Material. - Google Patents

Abstract

1,155,961. Fibrillating oriented films. O. B. RASMUSSEN. 29 June, 1966 [15 April, 1965], No. 16144/65. Heading B5B. As shown in Fig. 1 a film web 4 of organic polymeric material, which has been oriented in the longitudinal direction to such an extent that it can be caused to split up into fibres parallel to the longitudinal direction by subjecting it to friction in the transverse direction, is caused to pass between a roller A having a cogged periphery 1 and a second cogged roller 3 which meshes loosely with the roller A and serves to fold the film web 4 around the cogs of the roller A and thus cause the film web to become transversely pleated. The film web is thereby caused to partake in the rotation of the roller A but is only in weak engagement therewith, and when it meets a belt B which travels at a speed which is much lower than the peripheral speed of the roller A (e.g. only <SP>1</SP>/ 20 th to <SP>1</SP>/ 5 th that of the roller A) and consists of a material (such as lightly vulcanized natural rubber) which has a high coefficient of friction with respect to the film, the film web slips from A and becomes both pleated and longitudinally compressed and also split up into fibres parallel with the direction of travel of the film web. The periphery of the roller A is preferably covered with a sheath of an elastomer, such as polyurethane rubber, having a high wear resistance but only a low coefficient of friction with respect to the film. The pressure between the endless belt B and the roller A can be adjusted by means of the idler roller 2. The film web 4 may be partially split into fibres by means of a pair of nip rollers 5 which reciprocate axially in opposite directions. The belt B and roller A are cooled by means of streams of air directed on to them from the outlets 6 and 7. In the other embodiment shown in Fig. 2 narrow strips of film 8 supplied by a pair of feed rolls driven at a peripheral speed of 2À3 V are each passed through one of a set of parallel tubes 10 having funnel shaped inlets. Pressurized air supplied through nozzles 11 assists in transporting the film strips 8 through the tubes 10. Short lengths of rubber tubing 12 are fitted on to the outlet ends of the tubes 10 and are interconnected by a cord or wire 13 attached at the ends to coil springs 14 and 15. A vibrator 16, which may be actuated mechanically, pneumatically, or electromagnetically actuates the cord or wire to reciprocate the rubber tubings transversely whereby the film strips are rotated through an angle of about about 90 degrees about their longitudinal axes and at the same time pleated before passing through a fibrillating device comprising a rubber-covered roller 17 driven in the same sense as the upper roller of the rollers 9 at a peripheral speed V, and an endless rubber belt 18 driven at a linear speed of 0À1 V in the direction of travel of the belt. The roller 17 and belt 18 contact the pleated and turned on edge film strips 8 in a fibrillating zone 19. The film strips 8 are thereby subjected to a friction in the longitudinal direction and caused to fibrillate or split longitudinally to form fibrous webs which are gripped by a pair of nip rolls 20 driven at a peripheral speed 2À3 V. The fibrous webs are then passed through a second splitting or fibrillating device 20 and 21 similar to the first wherein the fibrous webs are further split or fibrillated to form webs of very fine interconnected fibres. The webs are thereafter carried through an electric oven 23 and a bulking device 24, 25 similar to the film splitting or fibrillating devices.