Spray-dried dye compositions, process for the production and use thereof
AssigneeSensient Imaging Technologies GmbH
InventorsVolker Lischewski, Christoph Roth, Michael Felicetti, Katrin Schwager
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Abstract
The invention relates to spray-dried, washfast dye compositions, preferably in the form of pigment powders, having a bleeding rate of ≦0.5% and consisting of water-soluble functional dyes, preferably food dyes, which are firmly incorporated in a silica matrix. Apart from low bleeding of dye, these compositions are remarkable for their high stability to pH changes and/or ascorbic acid. The invention is also directed to the production of the dye compositions and the use thereof. The dye compositions are preferably employed in coloring foods, cosmetics, pharmaceutical products, but also in other uses.
Claims12
Spray-dried dye compositions consisting of water-soluble functional dyes incorporated in an organosilane-based silicon dioxide matrix with bleeding rates of ≦0.5%.
A process for the production of spray-dried dye compositions consisting of water-soluble functional dyes incorporated in an organosilane-based silicon dioxide matrix with bleeding rates of ≦0.5%, comprising the steps of
- a) producing a silicon dioxide sol by weak acid hydrolysis of alkoxysi-lanes (organosilanes) in an aqueous organic solvent mixture at a pH of 5 to 6.5;
- b) adding a water-soluble dye;
- c) gelling by spray-drying the dyed sol.
(canceled)
Dependencies are inferred from the claim text.