Ciba-Geigy Corporation

Konrad Neumann

Ernst Schenkenberger

Wolfgang Rehmann

Friedrich Resch

Angelika Hayer

Horst O Brucker

Process for the preparation of granules by spray-drying of an aqueous suspension having a solids content of greater than/equal to 30% and containing at least one dye, fluorescent brightener or photoactivator and one condensation product from naphthalenesulfonic acid and formaldehyde and, if necessary, further auxiliaries and/or diluents. The spray-drying is carried out at a feed pressure of 50-150 bar, the residual moisture content of the product is less than 4%, and the granules obtained are in particular very pressure resistant and abrasion resistant.

Preparation of granules of dyes, optical whiteners or photoactivators

Described is a process for the production of negligibly dusty preparations of dyes and/or optical brighteners, which process comprises mixing an adhesive as e.g. sorbitol and a dust binding surface active agent into a mixture of dye or optical brightener and, optionally, further additives.

Process for the production of negligibly dusty preparations of dyes and

A process for the manufacture of fine-crystalline fluorescent brighteners of the bis-triazinylaminostilbene series in the .beta.-crystal form by mixing the water-containing fluorescent brightener filter cake with an aqueous dispersant solution at temperatures between 70.degree. and 85.degree. C. and grinding at this temperature, is provided.

Process for the manufacture of fine-crystalline fluorescent brighteners

Described is a process for the production of negligibly dusty preparations by spray drying an aqueous suspension containing at least one water-soluble dye or optical brightener and optionally further additives, characterized in that a dust-binding surface active agent is added to the aqueous suspension containing at least one adhesive as e.g. sorbitol and/or to the spray-dried product.

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Wyhlen, Germany

Konrad Neumann