Patent GB-991878-A (GB)
Title: Hard and flexible stoving enamels
Inventor: MURDOCK JAMES DAVID
IPC: C09D133/06
Filed: 1960-07-19
Abstract: Coating compositions comprise a copolymer formed by copolymerizing ethylenically unsaturated monomers and adapted to be cross-linked upon heating said copolymer having been formed in the presence of 2 to 20% by weight of the monomers of natural rubber, a synthetic rubber, a liquid rubber copolymer or a polyalkyl acrylate; a cross-linking agent for said copolymer when the copolymer does not contain mutually reactive sites; and a cross-linking catalyst. Specified rubbery materials include butyl rubber, polyisoprene, copolymers of butadiene with styrene, methyl methacrylate or acrylonitrile and optionally acrylic acid or acrylamide, and liquid copolymers of butadiene and styrene. Specified monomers include b -hydroxyethyl methacrylate, acrylic acid and glycidyl acrylate, a ,b -unsaturated acids, acrylamide, methacrylamide, N-methylol acrylamide and ethers thereof. Specified cross-linking agents are hexamethylol melamine, urea/formaldehyde resins and polyepoxides, e.g. vinylcyclohexene dioxide and condensates of epichlorhydrin with glycerol or diphenylol propane. Examples describe the polymerization in organic solvents in the presence of benzoyl peroxide and t.-butyl hydroperoxide of vinyl toluene, ethyl acrylate and acrylic acid in the presence of(1) a butadiene/styrene copolymer, (2) polyethyl acrylate, a butadiene/styrene copolymer, a butadiene/ acrylonitrile copolymer or natural rubber, and (8) a butadiene/styrene copolymer or natural rubber; the copolymerization styrene, ethyl acrylate and acrylic acid in the presence of (4) a butadiene/styrene copolymer, polyethyl acrylate, a butadiene/acrylonitrile copolymer or natural rubber; and the copolymerization of styrene, ethyl acrylate and acrylamide in the presence of (5 and 6) a butadiene/styrene copolymer, the product of Example 6 being methylolated and etherified with butanol; and coating compositions comprising the copolymers of Examples 1 and 2, condensates of epichlorhydrin with diphenylol propane or glycerol, titanium dioxide and dimethyl (coconut oil residue) amine; the copolymer of Example 5, butylated urea/formaldehyde resin and butyl sulphamic acid; the copolymer of Example 6, titanium dioxide and p-toluene sulphonic acid; the copolymers of Examples 1 and 2, titanium dioxide, the hexamethyl ether of hexamethylol melamine and p-toluene sulphonic acid; and the copolymers of Example 8, butylated urea/ formaldehyde resin, titanium dioxide and p-toluene sulphonic acid.  The compositions may be applied to metal substrates and baked. Specifications 681,031, 777,769, 842,641 and 880,356 are referred to.ALSO:Substrates, e.g. metals, are coated e.g. by spraying a dispersion in an organic liquid, with compositions comprising a copolymer of ethylenically unsaturated monomers adapted to be crosslinked on heating, said copolymer having been formed in the presence of 2-20% by weight of the monomers of natural rubber, a synthetic rubber, a liquid rubber copolymer or a polyalkyl acrylate; a crosslinking agent for said copolymer when the copolymer does not contain mutually reactive sites; and a crosslinking agent; and the coating cured by heating. Specified rubbery materials include butyl rubber, polyisoprene, copolymers of butadiene with styrene, methyl methacrylate or acrylonitrile and optionally acrylic acid or acrylamide, and liquid copolymers of butadiene and styrene.  Specified monomers include b -hydroxyethyl methacrylate, acrylic acid and glycidyl acrylate, a ,b -unsaturated acids, acrylamide, methacrylamide, N-methylol acrylamide and ethers thereof.  Specified crosslinking agents are aminoplasts and polyepoxides.  Examples describe the coating of phosphated steel panels with compositions comprising copolymers derived from vinyl toluene, ethyl acrylate and acrylic acid and a butadiene/styrene copolymer, a butadiene/acrylonitrile copolymer, polyethyl acrylate or natural rubber, a condensate of epichlorhydrin with diphenylol propane or glycerol, titanium dioxide and dimethyl (coconut oil residue) amine; a copolymer derived from styrene, ethyl acrylate and acrylamide and a butadiene/styrene copolymer, a butylated urea/formaldehyde resin and butyl sulphamic acid; the butyl ether of a methylolated copolymer derived from styrene, ethyl acrylate and acrylamide and a butadiene/styrene copolymer, titanium dioxide and p-toluene sulphonic acid; copolymers derived from vinyl toluene, ethyl acrylate and acrylic acid and a butadiene/styrene copolymer, a butadiene/acrylonitrile copolymer, polyethyl acrylate or natural rubber, titanium dioxide, the hexamethyl ether of hexamethylol melamine and p-toluene sulphonic acid; and copolymers derived from vinyl toluene, ethyl acrylate and acrylic acid and a butadiene/styrene copolymer or natural rubber, a butylated urea/formaldehyde resin titanium dioxide and p-toluene sulphonic acid; the coatings being cured by baking.  Specifications 681,031, 777,769, 842,641 and 880,356 are referred to.