GB1466005A - Self adhesive articles - Google Patents

Abstract

1466005 Strippable laminates GENERAL ELECTRIC CO 9 May 1974 [29 May 1973] 20486/74 Heading B5N An article comprises a unitary coherent backing, an organopolysiloxane pressure-sensitive adhesive layer on at least one face of the backing, and a releasable anti-stick layer comprising a silanol-stopped, dimethyl-polysiloxane fluid-coated sheet on the organopolysiloxane pressure-sensitive adhesive, the adhesive comprising the intercondensation product of a mixture containing an organopolysiloxane resin and at least one alkyl and/or alkenyl aryl polysiloxane gum. The backing may be a woven glass fabric, a silicone coated woven glass fabric, a polymeric film, e.g. a polyamide, polyimide, silicone, polytetrafluoroethylene, polychlorotrifluoroethylene, polypropylene, polyethylene, an acrylonitrile - butadiene - styrene copolymer, polyethylene terephthalate or an acetal polymer, a metallic foil, e.g. of aluminium or copper or a polyethylene coated paper. The organopolysiloxane resin is defined as being a polymer containing two or more siloxane units and having the average unit formula where each R (which may be the same or different) is a C 1-8 alkyl radical, a C 5-7 ring carbon atom cycloalkyl radical, a C 2-8 alkenyl radical, a mononuclear aryl radical, a mononuclear aryl alkyl radical having 1 to 6 carbon atoms in the alkyl group, or a halogenated derivative of the above radicals, OR<SP>2</SP> is a C 1-8 alkoxy radical, s is 1À0 to 1À7, q is 0 to 1À0, r is 0 to 1À0 and the sum of q+r is 0À01 to 1À0. The polysiloxane gum preferably has the formula where each R (which may be the same or different) is a monovalent hydrocarbon radical, a halogenated monovalent hydrocarbon radical or a cyanoalkyl radical, n is at least 500, and each R<SP>1</SP> (which may be the same or different) is hydrogen, alkyl or vinyl. The anti-stick layer may comprise a backing of paper or cloth, the silanol-stopped dimethylpolysiloxane coating thereon suitably having the formula where p is an integer of from 300 to 5260. The article of the invention may be made by mixing the resin and the gum, reacting the mixture at elevated temperature, dissolving the product in an aromatic solvent, e.g. benzene, toluene or xylene, applying the resultant solution to the backing, evaporating off the solvent and applying the coated surface of the anti-stick layer to the resultant pressuresensitive adhesive. A process for applying an article coated with an organo-polysiloxane pressure-sensitive adhesive to a substrate, e.g. steel, comprises providing an article according to the invention, separating the releasable anti-stick layer from the organopolysiloxane pressure-sensitive adhesive and applying the resultant product to the substrate.