Patent GB-920497-A (GB)
Title: Powdered coating compositions and the method for their preparation
IPC: C09D5/46
Filed: 1959-03-17
Abstract: A free-flowing film-forming coating composition for fusion coating processes comprises particles of a fusible resin and a powdered inorganic non-fibrous solid which is infusible at the temperatures used for fusing the resin, viz. 200 DEG  to 1000 DEG F., at least some of the resin forming a matrix surrounding each of the particles of the inorganic solid, and all the particles of the composition having a size in the range from 25 to 600 microns, the composition having a "fusion coating index" in the range from 250 DEG  to 600 DEG F.  The "fusion coating index" is the temperature to which an aluminium rod of specified dimensions must be pre-heated to obtain fusion of the composition in a continuous film coating the rod when immersed in a fluidized bed of the powder, under specified conditions.  The composition may be made by intensively mixing the molten resin with the inorganic solid, cooling and pulverizing.  The resin component may be one or more "B" stage epoxy resins, together with a curing agent, or a silicone resin, a nylon or a polyethylene resin.  The inorganic solid may be, e.g. zinc oxide or sulphide, titanium dioxide, lithopone, chromium oxide, an iron oxide, powdered aluminium, zinc or copper, calcium carbonate or metasilicate, magnesium oxide, aluminium silicate or oxide, barium sulphate, slate, or silicon carbide.  Examples describe the preparation of powdered mixtures of epoxy resins, metaphenylene diamine or dicyandiamide and calcium carbonate, rutile or calcium metasilicate, and of a silicone resin and rutile, and the application of these to metal articles, a steel plate and an aluminium rod by the fluidized bed technique. Specification 759,214 is referred to.ALSO:A free-flowing film-forming coating composition for fusion coating processes comprises particles of a fusible resin and a powdered inorganic non-fibrous solid which is infusible at the temperatures used for fusing the resin, viz. 200 DEG  to 1000 DEG F., at least some of the resin forming a matrix surrounding each of the particles of the inorganic solid, and all the particles of the composition having a size in the range from 25 to 600 microns, the composition having a "fusion coating index" in the range from 250 DEG  to 600 DEG F.  The "fusion coating index" is the temperature to which an aluminium rod of specified dimensions must be pre-heated to obtain fusion of the composition in a continuous film coating the rod when immersed in a fluidized bed of the powder, under specified conditions.  The composition may be made by intensively mixing the molten resin with the inorganic solid, cooling and pulverizing.  The resin component may be one or more "B" stage epoxy resins, together with a curing agent, or a silicone resin, a nylon or a polyethylene resin.  The inorganic solid may be, e.g. zinc oxide or sulphide, titanium dioxide, lithopone, chromium oxide, an iron oxide, powdered aluminium, zinc or copper, calcium carbonate or metasilicate, magnesium oxide, aluminium silicate or oxide, barium sulphate, slate, or silicon carbide.  Examples describe the preparation of powdered mixtures of epoxy resins, metaphenylene diamine or dicyandiamide and calcium carbonate, rutile or calcium metasilicate, and of methylphenylpolysiloxane or diphenylpolysiloxane resins and rutile.  Specification 759,214 is referred to.