Patent ES-306407-A1 (ES)
Title: Coating compositions of polymer dispersions in mixtures of high boiling and low boiling liquids
IPC: C08J3/09
Filed: 1964-11-25
Abstract: A coating composition comprises a dispersion of particles of film-forming polymer in an organic liquid consisting essentially of a mixture of high-boiling liquid and low-boiling liquid in which the high-boiling liquid is present in a proportion, relative to the solid content of the composition, of at least 1: 1.6 by volume, the high-boiling liquid having a solvating action on the dispersed polymer at romm temperature and both the low-boiling liquid and the mixture thereof with the high-boiling liquid being a non-solvent for the dispersed polymer at room temperature. The high boiling liquid may be a mixture of a strong solvent for the dispersed polymer, a nonsolvent and a plasticizer, and said non-solvent may be a liquid which is a non-solvent at room temperature but a solvent at stoving temperature. The preferred polymers are homo- and co-polymers of methyl methacrylate, betahydroxyethyl methacrylate, ethyl acrylate, methacrylic acid, acrylic acid and vinyl acetate, in particular a methyl methacrylate-methacrylic acid copolymer. In the examples, (1) a dispersion of polymethyl methacrylate in a low boiling aliphatic hydrocarbon, prepared by polymerizing methyl methacrylate in the presence of a lauryl methacrylate-glycidyl methacrylate copolymer grafted with methyl methacrylate, is blended with TiO2, plasticizer, pigment dispersing agent and a mixture of high-boiling aliphatic hydrocarbons and 2-(2-butoxyethoxy)ethyl acetate, (2) the said polymethyl methacrylate dispersion is blended with phthalocyanine blue, TiO2, carbon black, plasticizer, high-boiling aliphatic hydrocarbon and n-butyl acetate, (3) a pigmented dispersion is produced as in Example 1, using 3,5,5-trimethyl hexanol in place of the 2-(2-butoxy-ethoxy)ethyl acetate and (4) a composition comprising a polyvinyl acetate dispersion, prepared by polymerizing vinyl acetate in the presence of a lauryl methacrylate - glycidyl methacrylate copolymer grafted with vinyl acetate, butyl benzyl phthalate, aliphatic hydrocarbons and benzyl alcohol is produced. The compositions are applied to substrates and stoved (see Division B2).ALSO:Undercoated steel panels are sprayed with (1) a composition comprising a polymethyl methacrylate dispersion in a low-boiling aliphatic hydrocarbon, prepared in the presence of a lauryl methacrylate-glycidyl methacrylate copolymer grafted with methyl methacrylate, TiO2, plasticiser, pigment dispersing agent, high boiling aliphatic hydrocarbon and either 2- (2-butoxyethoxy) ethyl acetate or 3, 5, 5-trimethyl hexanol or with (2) a composition comprising the said polymethyl methacrylate dispersion, phthalocyanine blue, TiO2, carbon black, high boiling aliphatic hydrocarbon and n-butyl acetate and the coated panels are stoved. In Example 4, a chipboard panel is sprayed with a composition comprising a polyvinyl acetate dispersion in low boiling aliphatic hydrocarbon, prepared in the presence of a lauryl methacrylate - glycidyl methacrylate copolymer grafted with vinyl acetate, high boiling aliphatic hydrocarbon and benzyl alcohol and the film produced is dried at room temperature.