| 摘要 |
A free-flowing powder suitable for fusion coating of solid surfaces consists of (A) a mixture of (1) an epoxide resin, (2) a siloxane resin having an average of 1.0 to 1.7 monovalent hydrocarbon radicals per silicon atom, of which monovalent hydrocarbon radicals at least 10% by number are phenyl and (3) an anhydride of a polycarboxylic acid, said anhydride having a melting point of at least 100 DEG C. and (B) a filler. Specified epoxy resins are the reaction products of epichlorohydrin with bis (p-hydroxyphenyl)-dimethylmethane, bis-(chloro-p-hydroxyphenyl)-dimethylmethane and bis-(tetrabromo-p-hydroxyphenyl)-dimethylmethane. Specified siloxanes are monophenylsiloxane, copolymers of monophenyl siloxane with diphenyl siloxane, phenyl methyl siloxane, phenyl-ethyl siloxane or monopropyl siloxane, copolymers of monomethyl siloxane with phenyl methyl siloxane, copolymers of monophenyl siloxane, monomethyl siloxane, diphenylsiloxane and phenylmethylsiloxane, copolymers of monomethylsiloxane, monopropyl siloxane and monophenyl siloxane and copolymers of monoamylsiloxane, diphenylsiloxane and monomethysiloxane. Specified anhydrides are succinic, phthalic, pyromellitic, tetrachlorophthalic, trimellitic, hexachloroendomethylene - tetrahydrophthalic and naphthalene dicarboxylic acid anhydride. Specified fillers are phthalocyanines, alumina, titania, antimony oxide, ferric oxide, zirconia, silica, aluminium silicate, magnesium silicate, zirconium silicate, magnesium aluminium silicate, calcium aluminium silicate, carbon black, graphite, aluminium powder, iron powder, copper powder and zinc powder. Many of examples of compositions which are applied as coatings by the fluidised bed technique and aired by the application of heat are given.ALSO:Steel and aluminium panels are coated by immersion in a fluidized bed comprising (A) a mixture of (1) an epoxide resin, (2) a siloxane resin having an average of 1,0-1,7 monovalent hydrocarbon radicals per silicon atom, of which monovalent hydrocarbon radicals at least 10% by number are phenyl, and (3) an anhydride of a polycarboxylic acid, said anhydride having a melting point of at least 100 DEG C. and (B) a filler. Many siloxanes, epoxy resins and anhydrides are specified. Specified fillers are phthalocyanines, alumina, titania, antimony oxide, ferric oxide, zirconia, silica, aluminium silicate, magnesium silicate, zirconium silicate, magnesium aluminium silicate, calcium aluminium silicate, carbon black, graphite, aluminium powder, iron powder, copper powder and zinc powder. Many examples are given. Example 1, which is typical, describes the coating of preheated aluminium panels by dipping in a fluid bed comprising an epoxy resin derived from bis-phenol-A and epichlorohydrin, a copolymer of monophenylsiloxane and monopropylsiloxane, talc and pyromellitic dianhydride. |
