GB1378749A - Method and apparatus for making laminates - Google Patents

Abstract

1378749 Laminates including oriented material CONSOLIDATED-BATHURST Ltd 23 Nov 1971 [30 Nov 1970] 54276/71 Heading B5N Two layers are bonded between laminating rollers, one of the layers being a laterally oriented plastics film which is maintained under lateral tension and which has been slit, perforated, fibrillated or embossed, prior to lamination. Two plastics films may be laminated, optionally between surface sheets of paper, non-woven fabric or plastics, or one plastics film may be laminated between such surface sheets using adhesive. The laterally oriented plastics film may be a network produced by slitting, perforating or embossing a continuous film before stretching, or a film which has been fibrillated after stretching, and may also be longitudinally oriented. Lateral and longitudinal orientation may be carried out by tentering and by rollers respectively; the tentering device may also maintain the laterally oriented film under tension for laminating. The following specific laminated constructions are disclosed: (1) A film is slit laterally and stretched laterally before feeding between surface sheets. The slits may be a pattern of staggered rows or a row of long slits, so that stretching produces a flat film in the form of a network or a row of interconnected tapes, respectively; the film may be such that the apertures between the resulting ribbons are of substantially zero width. Such films having an unslitted border portion are described and claimed in Specification 1,378,750. (2) Two films are slit, one laterally and one longitudinally, and are laminated. (3) Two films are longitudinally slit and are laminated after one has been stretched laterally and the other longitudinally. (4) Two films are stretched, one laterally and the other longitudinally, and are fibrillated before laminating. (5) Two embossed films are each stretched laterally and longitudinally before laminating. (6) The film of interconnected tapes mentioned in (1) is laminated as a central layer between two similar layers whose tapes have been produced by longitudinal slitting and stretching and which are offset relative to the other, so that the product resembles a fabric. In the above embodiments longitudinally oriented films should be maintained under longitudinal tension for laminating. Slitting may be performed by heated knives carried on a roller and may be facilitated by using a freshly-extruded film. Embossing may be performed by a roller immediately after extrusion of the film or after heating to soften the film. Suitable fibrillation techniques are disclosed.