| 摘要 |
1,248,731. Film fibrillation; laminates. SMITH & NEPHEW RESEARCH Ltd. 8 Aug., 1968 [10 Aug., 1967], No. 36340/67. Headings B5B and B5N. [Also in Divisions B2 and D1] An adhesive tape comprises a backing of woven or non-woven fabric made from thin flat polymeric filaments obtained by slitting and drawing polymeric film and an adhesive on at least one surface of the backing. The film preferably comprises polypropylene, but other films may be used e.g. polyamide films or laminated films e.g. polypropylene/polyethylene or polyamide/polyethylene; the filaments from laminated films are preferably bonded one to another e.g. by heat or impulse sealing at cross-over points after the fabric is formed. In a preferred embodiment the filaments are obtained by slitting an extruded film having a thickness of 0À003 inch into ribbons “ inch wide which are then drawn under the action of heat under a draw ratio of 8 or 9 to 1 to produce filaments 1/10 inch wide and 1/1000 inch thick. In one drawing method the ribbons pass over a series of godet rollers and then through a heating zone to another series of rollers rotating 8 or 9 times the speed of the first roller. The fabric may be coated on one or both surfaces which may have been pre-treated by a corona discharge with an adhesive e.g. an auto adhesive butyl rubber composition of which several examples are described. The tensile strength of the backing fabric may be increased by giving it an extruded film coating of the same or another polymer, or the fabric may be laminated by means of adhesive to a preformed film of the same or another polymer, thus waterproofing the backing. A reinforced foam tape may be made by laminating the woven fabric to foamed material such as polyurethane, polyvinyl chloride or polyethylene by means of adhesive and spreading a further coating of adhesive thereon. A high strength extensible tape may be made by weaving or knitting the flat polymeric filaments in the form of a tube and cutting the tube on the bias into lengths. The material is preferably laminated by means of adhesive to an extensible film such as plasticized polyvinyl chloride or a copolymer of ethylene/vinyl acetate, and then provided with a further coating of adhesive. |
