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US 4,290,812 AGranted
Process for the production of inks free of foreign salts
AssigneeOlympia Werke AG
InventorEhrenfried Loock
Life of this patent
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Abstract
A method for the production of an ink suitable for use in ink-jet printing, free from foreign salts, made from technical dyes. A highly water-soluble dye is dissolved in water and precipitated with a precipitant amine. The precipitate is separated from the solution and distilled with water and a water-soluble amine of low volatility to convert the dye back to a soluble form.
Claims21
A process for the production of an ink, free from foreign salts, from a technical anionic dye, comprising:
- (a) dissolving at least one highly water-soluble dye in water to form an aqueous solution;
- (b) precipitating the dye from this aqueous solution by adding a precipitant organic amine to form an insoluble precipitated dye;
- (c) separating said precipitated dye from said solution;
- (d) converting said precipitated dye into a highly water-soluble form by distillation in the presence of water and a water-soluble amine of low volatility;
- and
- (e) dissolving the water-soluble dye obtained in step (d) in a solvent to obtain a dye solution.
3 more elements
Dependencies are inferred from the claim text.