Patent GB-1242054-A (GB)
Title: Improved coating compositions
Inventor: SMITH NORMAN DOUGLAS PATRICK
IPC: C09D7/65
Filed: 1967-06-08
Abstract: 1,242,054. Coating. IMPERIAL CHEMICAL INDUSTRIES Ltd. 31 May, 1968 [9 June, 1967], No. 26791/67. Heading B2E. [Also in Division C3] Liquid coating compositions comprise, in a liquid continuous phase, a film-forming material, a rubbery polymer in the form of dispersed particles of average diameter in the range 0.01-10Á and, optionally, a plasticiser, the composition being capable of forming a dry coating comprising a film of polymer formed from said material, wherein the rubbery particles remain in dispersion and adhere to the plasticised or unplasticised filmform polymer and the rubbery polymer has a primary glass transition temperature of less than 0C, a Youngs Modulus not more than a tenth of that of the film-form polymer and an extension to break at least ten times that of the film-form polymer. The film forming material may be an alkyd resin, an epoxy resin, a cellulose derivative, a polyimide, a polyester, a vinyl resin such as polystyrene or polyvinyl chloride, or an acrylic resin such as polymethyl methacrylate; alternatively the film-forming material may comprise a monomeric or oligomeric material which is polymerised or cured in situ on a substrate to form the solid film, e.g. low molecular weight amine-formaldehyde, phenol-formaldehyde, epoxy or polyester condensates, and a liquid monomer may provide the liquid continuous phase. The rubbery polymer suitably has as its main component an appropriate acrylate or methacrylate ester, vinyl acetate or propionate, a low polymer of ethylene oxide alkyl-terminated at one end and terminated by polymerisable unsaturation at the other end, an olefin or a diene; polyurethanes, polyamides and polyesters are also useful as the rubbery polymer. The liquid phase may comprise a volatile liquid. In Examples the following rubbery and film-forming components are used (1) polyethyl acrylate and hexamethoxymethyl melamine; (2) ethyl acrylateglycidyl methacrylate-methacrylic acid copolymer (EGM copolymer) and styrene-methacrylic acid-butoxymethylacrylamide copolymer or melamine-formaldehyde or air-drying alkyd resin; (3) EGM copolymer and either cellulose acetate butyrate or polymethyl methacrylate; (4) EGM copolymer and polymethyl methacrylate; (5) and (6) as for (2) or (3) but wherein the ethyl acrylate of the EGM copolymer is replaced by n-propyl acrylate or #-(#-butoxyethoxy)-ethyl acrylate respectively; (7) EGM copolymer and a mixture of diphenylolpropane diglycidyl ether and oligomers thereof; (8) vinyl acetate-2-ethyl-hexyl acrylate copolymer and polyvinyl alcohol; (9) vulcanised butyl rubber and polymethyl methacrylate; (10) polyurethane and polymethyl methacrylate; (11) polythene and polymethyl methacrylate; (12) polypropylene and styrenehydroxyethyl methacrylate copolymer; (13) EGM copolymer (additionally containing units of dimethylaminoethyl methacrylate) and methyl methcarylate-methacrylic acid copolymer. The compositions are suitable for application to substrates such as metal, wood and plastic substrates. The coatings can be crosslinked by stoving. In Examples, the compositions are applied to metals, e.g. tin foil or sheet metal, and to wood panels.