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US 6,648,959 B1Granted
Coloring pigment
AssigneeNederlandse Organisatie voor toegepast-natuurwetenschappelijk onderzoek TNO
InventorsHartmut Rudolf Fischer, Lawrence Fabian Batenburg
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Abstract
This invention relates to a method for preparing a coloring pigment, wherein an anionic or cationic clay, which clay contains substantially no agglomerates of clay sheets, is subjected to an ion exchange with an organic dye. The invention further relates to a coloring pigment and the use thereof for coloring substrates.
Claims11
A method for preparing a coloring pigment, comprising the steps of
- treating an anionic or cationic clay by dispersing and swelling the clay in water at a temperature between 20 and 60° C. which water is substantially free of ions, whereby the agglomerates of clay sheets are substantially broken;
- and thereafter
- subjecting the clay, containing substantially no agglomerates of clay sheets to an ion exchange with an organic dye in the presence of a surfactant, a block copolymer or a graft copolymer.
Dependencies are inferred from the claim text.