Patent GB-974874-A (GB)
Title: New pigment compositions
IPC: C09C1/00
Filed: 1962-06-27
Abstract: A nacreous coated mica pigment comprises a translucent micaceous flake substrate carrying on its surface a translucent metal oxide layer consisting of titanium dioxide, zirconium dioxide, ferric oxide, chromic oxide, or their hydrated forms, or vanadium pentoxide, or a mixture of two or more of these, of particle size less than 0.1 micron.  The metal oxide layer may constitute from 10 to 66% by weight of the pigment when comprised of titanium dioxide, zirconium dioxide, their hydrated forms, or two or more of these, and from 10 to 40% by weight of the pigment when consisting of the other oxides stated above.  The metal oxide layer may be from 20 to 250 millimicrons thick.  The micaceous flakes may have a surface area of 2-7 m.2/g., and the titanium dioxide layer may comprise from 50-600 mg./m.2 of the micaceous flakes and ferric oxide, chromic oxide, and vanadium pentoxide layers may comprise from 50-280 m.2/g.  The first metal oxide layers, when comprised of titanium or zirconium dioxides, or their hydrated forms, may have deposited thereon or intermingled therewith, a layer or a minor proportion of a different metal oxide selected from titanium oxide, zirconium oxide, alumina, zinc oxide, antimony oxide, tin oxide, iron oxide, copper oxide, nickel oxide, cobalt oxide, chromium oxide, and their hydrated forms.  The pigments may be produced by suspending the micaceous flakes in a dilute acidic solution of the appropriate metal salt, which is then slowly hydrolysed to a hydrous oxide which deposits on the surfaces of the flakes. Specified salts include titanyl sulphate, titanium oxychloride, titanium acetyl acetonate, triethanolamine titanate, zirconium oxychloride, zirconium sulphate, vanadyl sulphate, ferric chloride, ferric sulphate, chromic chloride, chromic sulphate. The titanium dioxide layer may also be formed by exposure of the micaceous flakes at 600 DEG  C. to the vapour of an organic titanate ester, e.g. tetraisopropyl titanate in the absence of air or water vapour. The acidic solution may contain besides a titanium salt, a salt of antimony, cobalt, tungsten, molybdenum or iron in amount such that the amount of metal oxide deposited therefrom does not exceed 20% of the titanium dioxide deposited.  The hydrous metal oxide deposited may be calcined at a temperature less than 1000 DEG  C. in the case of titanium dioxide, less than 800 DEG  C. for iron oxide, less than 700 DEG  C. for chromium oxide and 500 DEG  C. for vanadium oxide.  Deposition of further oxide layers may be effected either before or after calcination by hydrolysis of the appropriate acidic solutions.ALSO:Coating compositions, plastic films, and baked alkyd enamels have incorporated therein a pigment comprising a translucent micaceous flake substrate carrying on its surface a translucent metal oxide layer consisting of particles all of which are less than 0.1m in size of TiO2, ZrO2, Fe2O3, Cr2O3, or their hydrate forms, or V2O5. Further layers comprised of the oxides of Ti, Zr, Al, Zn, Sp, Sn, Fe, Cu, Ni, Co, Cr, Ni, or Cu, and their hydrated forms may be deposited. Typical formulations comprise (a) pigment, mixed acrylic ester polymer, butyl benzyl phthalate, monoacetate of ethylene glycol monoethyl ether, methyl ethyl ketone, toluene, (b) pigment, polyvinyl chloride, dioctyl phthalate, polyester resin, stabilizer (i.e. Ba-Cd-Zn-phosphite, stearic acid, (c) pigment, non-oxidising coconut oil-modified alkyd resin solution (60% solids), aromatic and aliphatic hydrocarbon solvents.ALSO:A nacreous pigment is comprised of a translucent micaceous flake substrate carrying on the surface of the flakes a translucent metal oxide layer consisting of hydrous and non-hydrous titanium dioxides, zirconium dioxides, ferric oxides, chromic oxides, or vanadium pentoxide, or a mixture of two or more of these, of particle size less than 0.1 micron.  The metal oxide layer may be from 20 to 250 millimicrons thick and it may constitute from 10 to 66% by weight of the pigment when consisting of hydrous and non-hydrous titanium dioxides, zirconium dioxides, or two or more of these, and from 10 to 40% by weight of the pigment when consisting of hydrous and non-hydrous ferric oxides, chromic oxides and vanadium pentoxide.  The titanium oxide layer may comprise from 50 to 600 mg./m2. of the micaceous flakes and the ferric oxide, chromic oxide, and vanadium pentoxide layers may comprise from 50 to 280 mg./m2. of the said flakes, which may have a surface area of 2 to 7 m2./gm.  The first metal oxide layers, when comprised of titanium or zirconium dioxides, or their hydrated forms, may have deposited thereon or intermingled therewith, a layer or minor proportion of a different metal oxide selected from titanium oxide, zirconium oxide, alumina, zinc oxide, antimony oxide, tin oxide, iron oxide, copper oxide, nickel oxide, cobalt oxide, chromium oxide, and their hydrated forms. The pigments may be produced by suspending the micaceous flakes in a dilute acidic solution of the appropriate metal salt, which is slowly hydrolysed to a hydrous oxide on the surfaces of the flakes. Specified salts include titanyl sulphate, titanium oxychloride, titanium acetyl acetonate, triethanolamine titanate, zirconium oxychloride, zirconium sulphate, vanadyl sulphate, ferric chloride, ferric sulphate, chromic chloride, chromic sulphate.  The layer of titanium dioxide may also be produced by exposure of the micaceous flakes at 600 DEG  C. to the vapour of an organic titanate ester, e.g. tetraisopropyl titanate in the absence of air or water vapour. The acidic solution may contain besides a titanium salt, a salt of antimony, cobalt, tungsten, molybdenum or iron in amount such that the amount of metal oxide deposited therefrom does not exceed 20% of the titanium dioxide deposited.  The hydrous metal oxide deposited may be subsequently calcined at a temperature less than 1000 DEG  C. in the case of titanium dioxide, less than 800 DEG  C. for iron oxide, less than 700 DEG  C. for chromium oxide and 500 DEG  C. for vanadium oxide.  Deposition of further oxide layers may be effected either before or after calcination by hydrolysis of the appropriate acidic solutions. The pigments may be incorporated in acrylic lacquers, alkyd enamels, and films of cellulose acetate and vinyl plastic.