GB1225544A - - Google Patents

Abstract

1,225,544. Nitrocellulose bonded laminates. IMPERIAL CHEMICAL INDUSTRIES Ltd. 16 Oct., 1969 [29 Oct., 1968], No. 51272/68. Heading B5N. A laminate comprises at least one polyolefin film bonded to a substrate by means of a nitrocellulose lacquer comprising industrial nitrocellulose, having a nitrogen content in the range 10À7 to 12À2% by weight, and plasticizer therefor, at least 50% by weight of the plasticizer being constituted by normally solid materials. Specified solid plasticizers are tricyclohexyl citrate, N-cyclohexyl p-toluene sulphonamide, N-phenyl p-toluene sulphonamide, N-cyclohexyl benzene sulphonamide, dicyclohexyl phthalate or dicyclohexyl tartrate. The lacquer may also contain a resin. The polyolefin film, e.g. polyethylene or polypropylene, may be subjected to a surface oxidative treatment, e.g. corona discharge, and may contain an anti-static agent, e.g. an amine or amide of specified formula. The substrate may be paper, cardboard, chipboard, metal sheet or printed materials, e.g. photographs and lithographs. The polyolefin film may be covered on both surfaces in laminates where the film is present as a sandwich layer. The laminate may be prepared by applying a nitrocellulose lacquer solution to the film or the substrate or both, evaporating the solvent, placing the film over the substrate with the lacquer between them and applying heat and pressure. When the substrate is porous, the lacquer solution may be applied to the film or substrate or both, the materials are assembled and held in contact under pressure and heat whilst the solvent is evaporated, this method being carried out continuously. The nitrocellulose lacquer solution may be used as an aqueous emulsion to reduce the viscosity or to prevent excessive penetration of lacquer into porous substrates.