Patent GB-1467700-A (GB)
Title: Laminate materials more especially for packaging purposes
IPC: B29C65/00
Filed: 1975-08-06
Abstract: 1467700 Laminating method and apparatus ZIRISTOR AB 6 Aug 1975 [15 Aug 1974] 32893/75 Heading B5N A web of laminate material for packaging (Fig. 1) comprises a base layer 1 having bonded to one face a covering layer 3 of plastics material extending from edge to edge of the base layer, and, bonded to the other face, a covering layer 2 of plastics material which stops short of one edge of the base layer to leave an edge zone 11 of the base layer uncovered, and extends beyond the opposite edge of the base layer to provide an edge flap 4 of the covering material projecting therefrom. The base layer may consist of a foamed plastics or fibrous material, e.g. paper, and each layer of covering material may be a layer of plastics or of aluminium foil coated on each face with plastics, polyethylene being the exemplified plastics. The product may be used in the formation of a packaging tube, the joint, formed by sealing in the regions 5, 6 enclosing the base layer. The web may be made by coating the base layer in the form of a web with the plastics material, severing the web along longitudinal parallel lines to form a plurality of separate webs, side by side, applying a common coating layer of the covering material to the uncoated faces of the severed webs, severing the common covering material along lines parallel to, but laterally spaced from, the lines of severance between the separate webs, the edge zones of the web defined by the severance lines of the common covering layer being rendered substantially adhesion-free, before or during application of the common covering layer. An apparatus for effecting the method comprises means, e.g. an extruder, for coating one face of a web of base material with covering material incorporating plastics material, means for longitudinally severing the web into a plurality of side-by-side webs, means for applying a common layer of covering material to the uncoated faces of the severed webs, means for rendering a narrow edge zone of each of the severed webs free of adhesion to the covering layer and means for longitudinally severing the common covering layer along lines parallel to, but laterally spaced from the severance lines between the webs, where the common covering layer is non-adherent to the severed web. In the embodiment described with reference to Fig. 2, a web of laminated material consisting of the base layer 1 and the layer 3 of coating material is fed directly from a laminating device (not shown) to a first set of spaced cutting elements 8, e.g. rotary cutters, an adhesion-free zone 9 on each strip being formed by the application of an adhesion-inhibitor, e.g. wax or a silicone, to the base layer prior to the application to the strips of a common covering layer 2, e.g. by extrusion and nip-rolling. The resultant composite material is then passed to a second set of cutting elements 10, e.g. rotary cutters similarly spaced but laterally displaced from the cutting elements 8 which divide the upper layer of coating material into strips but do not act fully through the thickness of the composite material. In an alternative embodiment, the formation of the adhesion-free zones is effected using a lamination roller provided with peripheral grooves, the width and spacing of which correspond to the width and spacing of the zones.