GB953761A - Thermosettable coating formulations and coated articles - Google Patents

Abstract

Curable compositions comprise a reactive epoxy compound which is a glycidyl ether of an aliphatic polyol or an epoxy nonalac having at least two oxinane rings per molecule, a film-forming addition polymer derived from one or a combination of alkenyl aromatic compounds and a , b -unsaturated carboxylic acids, the acid representing from 5 to 20% of the weight of the addition polymer, a catalyst for accelerating the crosslinking of the polymer with the epoxy compound and an organic solvent for the aforemention components. The glycidyl ethers which may be used are for example; the polyglycidyl ethers of glycols, glycerol, diglycerol, erythritol, pentaglycerol, pentaerytheritol, mannitol, sorbitol, polyallyl alcohol and polyvinyl alcohol. The nonoloes may be epoxylated by reaction with, for example, epihalohydrins, polyhalohydrins or polyepoxides and may be prepared from monoor polyhydric phenols (e.g. phenol, resorcinol and alkylphenols) and aldehydes such as metaldehyde, chloral, butyraldehyde and furfural. The alkenyl aromatic compounds may be, for example, styrene, vinyltoluene, a -methylstyrene and p-t-butylstyrene and the a , b -unsaturated carboxylic acids may be, for example, acrylic, methacrylic, ethacrylic, itaconic, maleic, fumaric and sorbic acids. Catalysts specified are quatenary ammonium compounds such as dodecyltrimethyl-ammonium chloride, tetramethylammonium chloride, trimethylbenzylammonium chloride and trimethylbenzylammonium acetate, and tertiary amines. The solvents may be esters, ketones (e.g. methyl ethyl ketone) or mixtures of hydrocarbons with esters and/or ketones. The compositions may also contain pigments such as titanium dioxide. They may be used as coating or laminating compositions. In comparative examples the epoxy resins used are epoxidised soya bean oil and the diglycidyl ether of bisphenol A.ALSO:Coating compositions (see Division C3) comprising a reactive epoxy compound which is a glycidyl ether of an aliphatic polyol or an epoxy novolac, a film-forming addition polymer derived from one or more alkenyl aromatic compounds and one or more a , b -unsaturated carboxylic acids, a catalyst for accelerating the cross-linking of the polymer with the epoxy compound and an organic solvent for the aforementioned components may be coated on to iron, aluminium and steel which may be primed or unprimed and on to wood, paper, fibreglass cloth, and composition boards such as particle board and chipboard by, for example, doctoring and brushing, and the coated substrate is finally baked. The solvent may be methyl ethyl ketone and the compositions may also contain pigments such as titanium dioxide. Articles which may be coated are automobile parts, home appliances, aluminium siding and cans. Examples are given in which the compositions are coated on to unprimed metal panels or phosphated steel panels.