GB1131179A - A process for the improvement of the suitability for the weaving of a film strip ofan organic thermoplastic macromolecular material - Google Patents

Abstract

1,131,179. Converting film strips into filaments. SHELL INTERNATIONALE RESEARCH MAATSCHAPPIJ N.V. 9 Aug., 1967 [11 Aug., 1966], No. 36614/67. Heading B5B. [Also in Division D1] The suitability for weaving of a film strip of thermoplastic macromolecular material is improved by rolling it up transversely to the longitudinal direction, i.e. in such a way that a crosssection normal to the longitudinal direction of the strip has the form of a spiral, preferably comprising 1¢ to 3 convolutions. The transverse rolling up of the film strip is effected by drawing the strip over and in contact with one single moving body, the directions of movement of the strip and the body making an angle with each other. The movement of the body may be rotational or travelling as in the case of a tape or cord. The angle may be a right angle, or as viewed on the side of the body towards which the strip travels, an acute or obtuse angle. As shown in Fig. 1, the strip is 2 unwound from a reel 1 and is drawn over and in contact with the edge of a rotating disc the shaft 4 of which is parallel to the direction of travel of the strip 2 from the reel 1 to the wind-up reel 5. As shown in Fig. 2, the strip 7 in travelling from the reel 6 to the reel 10 is drawn over and in contact with a rotating cone 8 the shaft 9 of which in the direction towards the nose of the cone makes an acute angle with the path of travel of the strip. The rotating body which the strip contacts in the manner shown in Fig. 2 may be a body of revolution other than a cone, for example, a cylinder. Instead of a disc, cone or roll, a cord or tape running over the periphery of a rotating disc or roll may be the moving body in contact with the film strip. Alternatively the moving body may be the smooth edge of a flange forming part of a reel from which the strip is unwound, as shown in Figs. 3 and 4. The moving body may be a second film strip, as shown in Fig. 5 wherein two originally parallel film strips 11 and 12 pass round a roll 15 after having passed through the slots of a guide means 13 and crossed over each other at a point of contact 14 pass round roll 15 and are withdrawn from the roll as the transversely rolled-up strips 16 and 17 travelling once again in parallel paths. The moving body with which the film strip makes frictional contact may be the film strip itself as shown in Fig. 6 wherein the portion 19 of the film strip travelling towards a rotating roll 18 rubs at a point 20 against a part 21 of the film strip travelling away from the roll 18. The film strip material may be a polyolefin such as polypropylene. The transverse rolling of the strip may be carried out at a temperature between the softening point of the strip material and 80‹ C. below this point, e.g. at a temperature between 100‹ C. and 165‹ C. The angle between the two directions of movement may lie between 10 and 170 degrees, preferably between 20 and 160 degrees. While being over and in contact with the moving body the strip may also be stretched at a stretch ratio between 5: 1 and 20: 1. The film strip may be impregnated with a stiffening agent to promote retension of the rolled-up form of the strip. The film strip must be under sufficient tension when travelling over and in contact with the moving body to cause the friction between the strip and body to be sufficiently high to cause the strip to become rolled up transversely. The thickness of the strip and its width are in general between 0À005 and 1 mm. and 2 and 20 mm. respectively.