Iron oxide coated mica nacreous pigments
AssigneeThe Mearl Corporation
InventorsLouis Armanini, Frank Bagala
Life of this patent
Estimating the term…
Abstract
Iron oxide coated mica nacreous pigments are improved by interposing a thin layer of titanium dioxide or aluminum oxide between the iron oxide and the mica.
Claims12
A process for the preparation of a nacreous pigment having increased stripping resistance which comprises:
- (a) coating micaceous particles with a colorless oxide selected from the group consisting of titanium dioxide and aluminum oxide in the amorphous form by deposition from a colorless oxide precurser containing coating bath at a rate such that the resulting colorless oxide layer is 5-35 mg/m.sup.2 and about 1 to 7 weight percent of the colorless oxide coated mica;
- (b) coating the colorless oxide coated micaceous particles with a mixture of .alpha. and .delta. iron oxide in the amorphous form in an amount such that the final calcined product contains about 20-50 weight percent iron oxide by deposition by hydrolysis from an iron compound containing coating bath;
- and
- (c) calcining the resulting particles at about 650.degree.-950.degree. C. to produce the desired nacreous pigment.
An iron oxide coated mica comprising mica having on the surface thereof a thin layer of colorless oxide selected from the group consisting of titanium dioxide, aluminum and the hydrous forms thereof, the amount of colorless oxide being 5-35 mg/m.sup.2 mica, and the colorless oxide having on the surface thereof a mixture of .alpha.-FeOOH and .delta.-FeOOH, the amount of said mixture being 20-50 weight percent of the total weight of the iron oxide coated mica.
Dependencies are inferred from the claim text.