Durable pigments for plastics

Improved alumina-coated inorganic pigments having a first coating of boehmite alumina, a second coating of amorphous alumina, and a third coating of boehmite alumina which exhibit good durability, dispersibility, and optical properties in plastic compositions are disclosed. Also disclosed is a proce...

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Bibliographic Details
Main Authors JOHN R. BRAND, KELLY A. GREEN
Format Patent
LanguageEnglish
Published 29.07.1999
Edition6
Subjects
ADHESIVES
CHEMISTRY
DYES
METALLURGY
MISCELLANEOUS APPLICATIONS OF MATERIALS
MISCELLANEOUS COMPOSITIONS
NATURAL RESINS
PAINTS
POLISHES
PREPARATION OF CARBON BLACK
TREATMENT OF INORGANIC MATERIALS, OTHER THAN FIBROUS FILLERS,TO ENHANCE THEIR PIGMENTING OR FILLING PROPERTIES
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Summary:Improved alumina-coated inorganic pigments having a first coating of boehmite alumina, a second coating of amorphous alumina, and a third coating of boehmite alumina which exhibit good durability, dispersibility, and optical properties in plastic compositions are disclosed. Also disclosed is a process whereby an aqueous slurry of an alumina-containing inorganic pigment is milled to achieve a particular particle size distribution, a first coating of boehmite alumina is precipitated onto the pigment material within a first pH range, a second amount of an alumina coating agent is added to the aqueous slurry within a second pH range to obtain a second coating of amorphous alumina over the first boehmite alumina coating, and then the pH of the slurry is adjusted to a third pH range thus forming a third boehmite alumina coating over the second amorphous alumina coating.
Bibliography:Application Number: AU19970026595