GB1269823A - Process and apparatus for the production of fibrous materials by fibrillation - Google Patents

Abstract

1,269,823. Film fibrillation. MONSANTO CHEMICALS Ltd. 5 May, 1970 [23 June, 1969], No. 31655/69. Heading B5B. Fibrous material is produced by passing a film or sheet of thermoplastic material which has been longitudinally orientated through the nip between a pair of rotating rolls, each roll having a series of circumferential ribs, the ribs of one roll intermeshing with those of the other so as to cause transverse stretching resulting in fibrillation. The film or sheet may consist of foamed thermoplastic material. The ribs may be thin plate-like projections which are integral with the rolls. The ribs may have a depth of from # inch to 1 inch and a thickness of from 1/16 to # inch. They may be 3/16 to # inch apart and their outer surfaces may be slightly roughened. The diameter of the rolls may be from 2 to 8 inches and they may be driven at a peripheral speed of from 10 to 1000 feet per minute. The film or sheet preferably comprises. a polymer or copolymer of an ethylenically unsaturated monomer, particularly high density polyethylene. The fibrillated web may be subjected to the. action of a turbulent stream of air to cause further fibrillation. The film or sheet is preferably stretched transversely before being passed through the nip of the' rolls, for example by passing it across a surface such as a spreader bar curved in a direction transverse to the direction of travel of the film or sheet and thereafter over an associated plain idler roller to flatten out the film or sheet before it is passed through the nip of the ribbed rolls.