Patent GB-1037782-A (GB)
Title: Thermosetting coating compositions
Inventor: JONES DAVID VERNON HUDSON
IPC: C08F8/00
Filed: 1962-03-26
Abstract: A thermosetting acrylic copolymer is prepared by esterifying with a polyhydric alcohol, a copolymer of maleic anhydride with a comonomer selected from acrylic and vinyl compounds, said comonomer material including at least 25% by weight of an alkyl acrylate or methacrylate, the alkyl group of which contains 4 or less carbon atoms, the amount of polyhydric alcohol used being at least 1 molar equivalent per anhydride group in the copolymer. The polyhydric alcohol may be a polyhydroxy alkane such as glycerol or trimethylol propane, a glycerol partial fatty ester produced for example by reacting a polyhydric alcohol with a triglyceride vegetable oil, an alkyd resin with residual hydroxyl groups or a condensate of a polynuclear phenol with epichlorohydrin.  The copolymers may be employed in coating copositions with one or more of the following: amino resins optionally alkylated, epoxy resins, polyepoxy compounds, epoxidized vegetable oils, maleic anhydride copolymers, phenol formaldehyde condensates and formaldehyde modified acrylamide and substituted acrylamide copolymers.  Salts of the copolymers with volatile bases such as ammonia or an amine may also be used in coating compositions with water-dilutable amino-resins, aqueous dispersions of epoxy resins and water-dilutable phenol-formaldehyde condensates.  Curing of these compositions is achieved by stoving at 120 DEG  to 200 DEG  C.  In the Examples: (1) a maleic anhydride/ethyl acrylate copolymer is esterified with (a) glycerol, (b) an oil-modified alkyd resin, (c) a diphenylol-propane/epichlorohydrin condensate or (d) alkali refined soya bean oil and glycerol.  The copolymer half ester which may be in the form of an amine salt, is then mixed with (a) recrystallized hexa (methoxy methyl) melamine, (b) butylated melamine-formaldehyde condensate, (c) diphenylol propane epichlorohydrin condensate or (d) bisphenol epichlorohydrin condensate; TiO2 may be added and the mixture thinned to produce a paint; (2) a styrene/butyl acrylate/maleic anhydride copolymer is esterified with trimethylol propane and the product mixed with (a) butylated melamine-formaldehyde condensate and diphenylol propane epichlorohydrin condensate, (b) a styrene acrylamide copolymer modified with formaldehyde and then butylated, or (c) soya bean oil modified alkyd resin, and then thinned to produce a paint.ALSO:Tin plate and steel panels are spray coated and then stored with a paint composition having as an essential component a maleic anhydride copolymer which has been esterified with a polyhydric alcohol the amount of polyhydric alcohol used being at least 1 molar equivalent per anhydride group in the copolymer, the comonomer material being selected from copolymerizable compounds having an acrylic group and vinyl compounds, the comonomer material including at least 25% by weight of an alkyl acrylate or methacrylate, the alkyl group of which contains no more than 4 carbon atoms.  The other resinous component of the paint composition is an addition or condensation polymer. Salts of the copolymers with volatile bases may be used.  In the examples (1). An esterified maleic anhydride/ethyl acrylate copolymer, which may be in the form of an amine salt, is mixed with (a) recrystallized hexa (methoxy methyl) melamine, (b) butylated melamine formaldehyde condensate, (c) diphenylol propane epichlorohydrin condensate or (d) bisphenol epichlorohydrin condensate, titanium dioxide pigment optionally being present, and the composition thinned to produce a paint and (2).  An esterified styrene/butyl acrylate/maleic anhydride copolymer is mixed with (a) butylated melamine formaldehyde condensate and diphenylol propane epichlorohydrin condensate, (b) a styrene/acrylamide copolymer modified with formaldehyde and then butylated or (c) a soya bean oil modified alkyd resin, and then thinned to produce a paint.