GB1141981A - Iridescent bodies and coating compositions and composite structures comprising them - Google Patents

Abstract

1,141,981. Iridescent thermoplastic laminates. DOW CHEMICAL CO. 21 Jan., 1966, No. 2848/66. Headings B5B and B5N. [Also in Division B6] A synthetic resinous thermoplastic body has a thickness of up to 10 mils. and is composed of at least 10 generally parallel layers of transparent thermoplastic resinous material, at least 20% of the layers having a thickness between 0À05 micron and 5 microns and adjacent layers differing in refractive index from each other by at least 0À03. As described a plurality of the bodies is produced either by simultaneous extrusion of a plurality of layers from a single die and stretching of the extrude at thermoplastic temperatures to form a film, or by depositing thin layers of thermoplastic material on a substrate and subsequently stretching the layers from the substrate to form a film, the film in either case being subsequently cut up to form the bodies, which may take the form of elongated strips, rectangles, circles or random shapes. The bodies preferably include at least 50 layers of 0À05 to 1 micron thickness, and a table of thermoplastic materials which can be used for the layers, together with their refractive indices, is given. The bodies are secured by a binder 11 to a substrate 16 of e.g. glass, wood, metal, or polystyrene, to produce an iridescent coating on the substrate. The binder may be a synthetic film forming latex, e.g. white or black latex paint, a lacquer, a drying oil, or a varnish, and is preferably an aqueous dispersion of a polymer of 67 parts by weight ethyl acrylate and 33 parts by weight methyl methacrylate. The bodies are secured to the substrate either by mixing the bodies with the binder and then coating the substrate with the mixture, or by first coating the substrate with the binder and then applying the bodies. The binder or mixture is applied to the substrate by spraying, brushing, dipping, or rolling. Preferably the bodies are applied by an air stream to a coated substrate. The bodies may be pressed into the binder by a felt or non- adherent covered roll. In a further embodiment the substrate is a pressure-sensitive adhesive tape into the adhesive of which the bodies are pressed by a roller.