ES318251A1 - Coating compositions - Google Patents

Abstract

A saturated, linear backbone polymer is reacted in bulk with a graft monomer in the presence of an initiator the backbone polymer is capable of solvation by a selected organic liquid medium and the graft monomer gives a component not capable of solvation by said medium, or vice versa. The backbone polymers specified are polymers of an ester of (meth) acrylic acid and an aliphatic alcohol of 4 to 26 carbon atoms, e.g. 2-ethylhexyl acrylate, n-, or iso-butyl methacrylate, lauryl methacrylate and stearyl methacrylate, and copolymers thereof with e.g. methyl (meth)acrylate, ethyl acrylate, styrene, 3 - (b - methacryloxyethyl) - 2,2-spirocyclohexyl - oxazolidine, glycidyl methacrylate or tetrahydrofurfuryl methacrylate: polypropylene, polybutylene and polyisobutylene are also specified. The initiator is preferably a peroxide. A plasticising compound e.g. one of formula <FORM:1101983/C3/1> wherein R is an alkyl radical of 1 to 20 carbon atoms, an aliphatic ether or ester radical of 3 to 20 carbon atoms or an aralkyl radical of 7 to 20 carbon atoms and n is 0 or 1, benzyl acetate, 2,2,4 - trimethyl - 3 - acetoxy - 1 - pentanol isobutyrate, diethyl succinate, 2-n-butoxyethyl acetate, diethylene glycol monoethyl ether or cyclohexanone may be present. Dispersions of film-forming polymers are prepared by polymerizing monomers in organic liquids containing a graft copolymer of the invention. Coating compositions are prepared from the polymer dispersions by adding coalescing agents, plasticizers and pigments and applied to e.g. metal surfaces (see Division B2). In Example 1, methyl methacrylate is polymerized in an aliphatic hydrocarbon medium containing poly (2-ethylhexyl acrylate) grafted with methyl methacrylate, using t.-butyl perpivalate as catalyst, and TiO2, n-butyl benzyl phthalate and 2-ethoxyethyl acetate are added to the resulting dispersion. Similar dispersions are produced in Examples 2 and 3, in which isooctyl benzyl phthalate or another of the aforementioned plasticizers is present during the graft polymerization. In Example 4, methyl methacrylate (or styrene or vinyl acetate) is similarly polymerized using benzoyl peroxide as catalyst in medium containing poly(lauryl methacrylate) grafted with methyl methacrylate (or styrene, or vinyl acetate). Methyl methacrylate is polymerized in Example 5 using azobisisobutyronitrile as catalyst in a medium containing polyisobutylene grafted with methyl methacrylate and in Example 6 an ethyl acrylate-methyl methacrylate copolymer of particle size 0.5 micron is produced using poly(butyl methacrylate) grafted with the said two monomers as dispersing agent. In Example 7 lauryl methacrylate is polymerized using polymethyl methacrylate grafted with lauryl methacrylate as dispersing agent whereas in Example 8 methyl methacrylate is polymerized in the presence of poly (lauryl methacrylate-tetrahydrofurfuryl methacrylate) grafted with methyl methacrylate. Reference has been directed by the Comptroller to Specifications 941,305 and 934,038.ALSO:Metallic, cellulosic, plastic, glass and fabric substrates are coated with a composition comprising a dispersion in an organic liquid of a film-forming polymer, a graft copolymer, a coalescing agent, a plasticiser and a pigment. The production of suitable polymer dispersions is described (see Division C3). In Example 1 a composition formed by mixing a dispersion prepared by polymerising methyl methacrylate in an aliphatic hydrocarbon medium containing poly (2-ethylhexyl acrylate) grafted with methyl methacrylate with TiO2, n-butyl benzyl phthalate and 2-ethoxyethyl acetate is sprayed on to a primed automobile. The resulting film is baked at 120 DEG C. Reference has been directed by the Comptroller to Specifications 941,305 and 934,038.