Improvements relating to laminated plastics sheets

1,069,487. Laminates. FORMICA INTERNATIONAL Ltd. Aug. 4, 1965 [Aug. 31, 1964], No. 35535/64. Heading B5N. A method of making laminated plastic sheet materials from assemblies of core laminµ comprising fibrous sheets impregnated with a synthetic resin, the assemblies having at least one surface layer of a fluorine-containing organic polymer, comprises pressing together a plurality of assemblies in which a surface layer of a fluorine-containing organic polymer of an assembly is in direct face-to-face contact with a surface layer of a fluorine-containing organic polymer of an adjacent assembly while heating them to a temperature sufficient to cure the thermosetting resin without causing the adjacent surface layers of fluorine-containing organic polymer to cohere. The fluorine containing polymers, e.g. polyvinyl fluoride, polyvinylidene fluoride, polytrifluorochloroethylene or polytetrafluoroethylene may be transparent or pigmented and the sheets of the assembly adjacent thereto are preferably decorated paper sheets impregnated with an aminotriazine-aldehyde resin. The polymer layer is preferably oxidized on the surface contacting the remainder of the assembly. The core material may be paper, optionally admixed with wood chips, glass fibre, cotton fibre or asbestos and may be rendered fire-resistant. Specified impregnants for the remaining core sheets are condensates of aldehydes with urea, phenols, aminotriazines or mixtures thereof.