SUBSTRAT DEGRADABLE, TEL QU'UN RECIPIENT METALLIQUE POUVANT ETRE CORRODE, REVETU SUR UNE SURFACE D'UNE RESINE

摘要

1381294 Coated metal ECOPLASTICS Ltd 14 Feb 1972 [15 Feb 1971] 4682/71 Heading B2E [Also in Division C3] A. corrodible metal substrate is coated on at least one surface with a resin which is initially water-impermeable but which undergoes photodegradation to a water-permeable condition after exposure to ultra-violet light, the resin containing within the molecule a photochemically active ketone carbonyl group present in the unit in which R is alkyl, cycloalkyl, aryl, alkenyl, or alkaryl having up to 10C, R1 is hydrogen or alkyl, cycloalkyl, aryl or alkaryl having up to 7C. The substrate may be steel and may be a metal container. The coating may be prepared by -applying an initially water-soluble or susceptible, resin having photochemically active ketone carbonyl groups in its molecular structure from an aqueous coating composition, and then cross-linking the resin to a water-impermeable form. Alternatively the resins may be applied as melts or solutions in non-aqueous solvents. The coating resin may be a copolymer of an ethylenically unsaturated monomer OH 2 =C-X (in which R2 is hydrogen or an | R2 alkyl group and X is a functional group such as phenyl, substituted phenyl, carboxylic acid, ester) and a vinyl ketone of formula Suitable ethylenically unsaturated monomers are ethylene, styrene, methyl acrylate, methyl methacrylate, methacrylonitrile, acrylonitrile, butadiene, isoprene, vinyl acetate, vinyl chloride, acrylic acid, methacrylic acid. The vinyl ketone may be methyl vinyl ketone, ethyl vinyl ketone, propyl vinyl ketone, isopropyl vinyl ketone, butyl vinyl ketone, methyl isopropenyl ketone, ethyl isopropenyl ketone, methyl isobutenyl ketone or phenyl vinyl ketone. Alternatively the resin may be a condensation product of a ketone of formula: (where n and m are 1-10, R and R1 are as defined above, X and Y are each functional groups capable of condensation with other monomers used in the resin and selected from hydroxy, carboxyl, ester, amine, carbonyl halide, isocyanate and epoxy) with a difunctional monomer capable of condensation therewith, e.g. terephthalic, adipic or isophthalic acid to form polyester resins, or dibasic isocyanates to form polyurethanes. The ketone monomer may be a dibasic acid, diamine or a glycol, examples of which are given. The ketone carbonyl group may be introduced into polypropylene by oxidizing in air or oxygen or with an axidizing agent such as chromic acid.