Patent ID: 8431630

Claim:
A method for manufacturing a water resistant aluminum pigment dispersion comprising the steps of: (a) forming a composite pigment base by sequentially laminating a peeling resin layer and an aluminum layer on a sheet-shaped substrate; (b) forming a composite pigment by peeling the sheet-shaped substrate from the composite pigment base; (c) forming an aluminum pigment dispersion by pulverizing the composite pigment, and (d) forming an aqueous composition that incorporates the pulverized composite pigment; wherein at least one of the steps (b) and (c) is performed in a composition comprising an organic solvent to which a phosphorous surfactant is added to impart water resistance to the composite pigment so as to inhibit whitening of the composite pigment when it is incorporated into the aqueous composition in step (d), wherein the aqueous composition includes the composite pigment in the form of plate-shaped particles and wherein, when a long diameter, a short diameter, and a thickness of a plain surface of each of the plate-shaped particles are represented by X, Y, and Z, respectively, a 50% average particle diameter R50 of a corresponding circle which is obtained by calculation from areas of X-Y plain surfaces of the plate-shaped particles is in the range of 0.75 to 2 μm, and R50/Z>5 is satisfied; and wherein the water resistant aluminum pigment dispersion is suitable for inkjet printing.