FIBRILLATION OF STRIATED FILMS

摘要

1,274,990. Film fibrillation. HERCULES Inc. 23 Dec., 1970 [23 Dec., 1969], No. 61167/70. Heading B5B. Apparatus for fibrillating striated films comprises a rotatable cylindrical threaded member 1 having at least two sets of diametrically opposed helical threads, adjacent sets of threads 2, 3 being left-handed and right-handed, respectively, and having an equal number of threads which are staggered in one set with respect to the other so that the threads 4 of one set abut the grooves between the threads 5 on the other set. In a typical operation (Fig. 2) a uniaxially oriented striated film 10 is drawn by pull rolls 11 from a supply roll (not shown) between idler rolls 12 and is contacted with the rotating threaded fibrillation device 13. Preferably the fibrillation roller has two sets of threads, the total number of threads/inch being the same as the number of striations/inch on the film. The number, N, of reversals of thread direction per linear inch of film travel is given by the formula N = (RW)/V, where R is the number of reversals per revolution of the device, W is the r.p.m. of the device and V is the speed of travel of the film in inches/min. For the production of continuous filaments N is at least 10 and preferably 15, for an incompletely fibrillated film of net-like structure N is preferably less than 10. The apparatus is suitable for fibrillating any striated film material, suitable polymeric materials being polyolefins, polyethylene terephthalate, nylon, polymethyl methacrylate and polyvinylacetate. The following abridgments are included in this series since the Specifications were, through an error, not allotted to this Group. References to them will be found in the indexes to this volume.