GB1125400A - Process for the manufacture of a film laminate - Google Patents

Abstract

1,125,400. Laminates. KALLE A.G. 16 Dec., 1965 [17 Dec., 1964], No. 53476/65. Addition to 1,074,256. Heading B5N. A film laminate is produced by placing together two polypropylene film layers, at least one of which is coated on at least one surface with a layer of a plastics material which can be stretched at least to the same extent as the polypropylene film and softens below about 150‹ C., with the plastics layer or layers which may be foamed between them and the resulting laminate is stretched as a unit at least uniaxially by at least 300%. The plastics material may be coated on to the polypropylene film or films in the form of a solution, dispersion, melt, or a self-supporting film, and is caused to solidify during or after the stretching. The surfaces of the polypropylene films to be facing surfaces may each be coated with a plastics layer and a further layer of a synthetic or natural substance with a softening point below 150‹ C. interposed between the coated films before they are placed together. The plastics material may be polyolefin, e.g. low density polyethylene, polyisobutylene, polyvinyl acetal, alkyd resin, synthetic rubber, polymerizable monomers or prepolymers, such as a mixture of unsaturated acid esters and styrene, copolymers of vinylidene chloride such as vinylidene chloride-acrylonitrile-itaconic acid polymer or bitumen, polymerizable material being polymerized during or after stretching, e.g. by heating or irradiation. The plastics material may contain suitable fillers, e.g. cork, shale, graphite, or talc powder or non-oriented fibres. A further intermediate layer, which may be foamed, may be applied between the polypropylene films and may be of bitumen, waxes and high molecular weight hydrocarbons in the form of paraffin waxes.