GB1180545A - Improvements in and relating to the Manufacture of Fibres from Plastics Films Oriented in one Direction - Google Patents

Abstract

1180545 Fibrillating thermoplastic polymer films KALLE A G 10 April 1968 [12 April 1967] 17226/68 Heading B5B [Also in Division D1] Fibres are made by suspending pieces cut from a film of synthetic organic thermoplastic polymeric material which has been uniaxially oriented at a stretch ratio sufficiently high to render it fibrillatable by mechanical treatment, in a liquid which is not a solvent for the film material and exposing the suspension tothe action of shearing forces which may for example, be produced by means of high-speed stirrers. The suspending liquid may be water. The film material may be a polyolefin, a polyvinyl compound a polyester or a polyether. The film may consist of two or more miscible or immiscible components, e.g. polypropylene and polyamide. The length of the piece or strip cut from the film may be from about 10 to about 40 mm., preferably 15 to 25 mm., and its width may be 5 to 50 mm. The thickness of the film may be between 5 and 40 microns, preferably 8 to 20 microns. An anti-agglomeration agent which is soluble in the suspension liquid may be added to the liquid. When water is used as the suspending liquid, polyvinyl alcohol or a watersoluble cellulose ether, particularly hydroxyethyl cellulose, may be added to the water. In addition, a surfactant such as a sodium alkyl sulphonate may be added to the water. The content of film pieces in the liquid may be 1 to 15 grams per litre. The fibres are suitable for further processing into non-woven fibrous or textile structures, particularly for the production of mats or fleeces. After separation of the fibres from the liquid in which they are suspended, such structures may be immediately formed from the resulting fibre slurry by consolidation by conventional methods and may be thermally solidified or reinforced by means of binders. In an example, 30 mm. wide strips of an 8 micron thick which has been uniaxially oriented in the longitudinal direction by stretching it at a stretch ratio of 9:1 and at a temperature of 150‹ C. Polypropylene film are cut into 5 to 20 mm. length portions, 80 grams of which are suspended in 40 litres of water containing 0À5% of hydroxyethyl cellulose and 0À15% of a wetting agent and the pieces of film are fibrillated by intensely stirring the suspension for 4 minutes. The fibres are deposited on a travelling endless screen belt to form a mat or fleece which is dried. The fibres in the fleece have good cohesive properties promoted by the binding effect of the hydroxyethyl cellulose.