Iron blue nacreous pigments
AssigneeThe Mearl Corporation
InventorLouis Armanini
Life of this patent
Estimating the term…
Abstract
An iron blue coated substrate nacreous pigment which yields less than ten parts per million of water-soluble cyanide due to the stability thereof to heat during drying is prepared by the admixing of the substrate, ferric ion reactant, and ferrocyanide reactant under conditions such that the ferric ion and ferrocyanide reactants are in substantially stoichiometric proportions and the pH is at constant value within the range of 2.5-4.0, and adding an aluminum-containing reactant so as to form aluminum hydroxide in addition to the iron blue on said substrate. The product shows a brighter, cleaner, and purer blue color than iron blue coated substrate products prepared by other procedures.
Claims11
An iron blue coated nacreous pigment substrate of less than 10 ppm water soluble cyanide.
A method of preparing an iron blue coated nacreous pigment substrate of less than 10 ppm water soluble cyanide comprising admixing the substrate, ferric ion reactant and ferrocyanide reactant under conditions such that the ferric ion reactant and ferrocyanide reactant are always substantially in stoichiometric proportions and the pH is at a constant value within the range of 2.5-4.0, and adding an aluminum containing reactant so as to form aluminum hydroxide in addition to the iron blue on the substrate.
Dependencies are inferred from the claim text.