Patent GB-989371-A (GB)
Title: Hard and flexible stoving enamels
Inventor: HEPPOLETTE ROBERT LOUIS
IPC: C09D151/00
Filed: 1960-07-19
Abstract: Coating compositions comprise a copolymer of ethylenically unsaturated monomers including 2 to 15% by weight of the monomers of an a ,b -unsaturated carboxylic acid and 85 to 98% by weight of the monomers of copolymerizable neutral monomers, said monomers having been copolymerized in the presence of 2 to 20% by weight of the copolymerized monomers of a rigid polymer of one or more ethylenically unsaturated compounds; 5 to 55% by weight of the copolymerized monomers of a polyepoxide; and a basic catalyst. Specified acids are acrylic, methacrylic, maleic, fumaric, itaconic and crotonic acids.  Specified comonomers are styrene and alkylated styrenes, acrylic and methacrylic esters, vinyl chloride, acrylonitrile, acrylamide and N-methylol acrylamide. The rigid polymer may be derived from styrene or alkylated styrenes, ethylene, propylene or methacrylic esters. Copolymerization may be effected in organic solvents in the presence of organic peroxides or azo compounds.  Specified polyepoxides are vinylcyclohexene dioxide and condensates of epichlorhydrin with glycerol or diphenylol propane. Specified basic catalysts are sodium hydroxide, amines, quaternary ammonium hydroxides, and polymers of vinyl pyridine and dimethylaminoethyl methacrylate.  The compositions may be applied to metal substrates and cured by heating.  Examples describe the preparation of copolymers by copolymerizing vinyl toluene, ethyl acrylate and acrylic acid in xylene in the presence of benzoyl peroxide and t.-butyl hydroperoxide and (1) polystyrene, polyethylene or polyvinyl toluene, and (2) polymethyl methacrylate; and of coating compositions comprising the above polymers, titanium dioxide, or dimethyl(coconut oil residue) amine and (1) and (2) an epichlorhydrin diphenylol propane condensate and (3) and epichlorhydrin glycerol condensate.  Specifications 731,946, 777,769 and 880,356 are referred to.ALSO:Substrates, e.g. metals, are coated with compositions comprising a copolymer of 2-15 weight per cent of an a -b -unsaturated carboxylic acid and 85-98 weight per cent of neutral ethylenically unsaturated monomers copolymerizable therewith, said acid and monomers having been copolymerized in the presence of 2-20 weight per cent, based on the monomers and acid, of a rigid polymer of one or more ethylenically unsaturated compounds; 5-55% by weight of the copolymerized monomers and acid of a polyepoxide; and a basic catalyst; and the coating cured by heating.  Specified acids are acrylic, methacrylic, maleic, fumaric, itaconic and crotonic acids; specified comonomers are styrene and alkylated styrenes, acrylic and methacrylic esters, vinyl chloride, acrylonitrile, acrylamide and N-methylol acrylamide.  The rigid polymer may be derived from styrene or alkylated styrenes, ethylene, propylene or methacrylic esters. Specified polyepoxides are vinyl cyclohexane dioxide and condensates of epichlorhydrin with glycerol and diphenylol propane.  Specified basic catalysts are sodium hydroxide, amines and quaternary ammonium compounds.  In examples phosphated steel panels are coated by spraying with compositions comprising titanium dioxide, dimethyl (coconut oil residue) amine and the products derived by copolymerizing vinyl toluene, ethyl acrylate and acrylic acid in the presence of (1) polystyrene, polyethylene or polyvinyl toluene, (2) polymethyl methacrylate, and (3) polystyrene, the polyepoxides being condensates of epichlorhydrin with (1 and 2) diphenylol propane and (3) glycerol; and stoved. Specifications 731,946, 777,769 and 880,356 are referred to.