Bayer Aktiengesellschaft

Jochen Koll

Reinhold Hornle

Hans-Heinz Molls

Karlheinz Wolf

Joachim Wolff

Volker Paulat

Konrad Nonn

Reinhold M Klipper

Joachim Konig

Peter M Lange

Friedhelm Muller

Udo Eckstein

Horst Brandt

Harald Gleinig

Hans Theidel

Fritz Bremer

Detlef Szeymies

Willy Schiwy

Erhard Schuffenhauer

Gottfried Dick

Friedrich Kunert

Werner Bieber

Fluorescent brightener salts of the formula ##STR1## in which A denotes the anion of an anionic cellulose fluorescent brightener,

Paper-coating slips containing fluorescent brighteners

Ultrafiltered solutions of the dyestuff of the formula ##STR1## (Me=cation) such as is obtained directly on synthesis, are distinguished by an increased tinctorial strength in pad-steam dyeing of cellulose fibres.

Process for the preparation of a concentrated aqueous reactive dyestuff

Stable, concentrated aqueous solutions of, in particular, anionic reactive dyestuffs are obtained in a comparatively simple manner by freeing from salts, preferably by means of membrane separation processes, solutions of these substances just as they are obtained in the course of synthesis, and by replacing, with the aid of ion exchangers, the cations which cause sparing solubility.

Process for the preparation of concentrated solutions of anionic

The lyotropic, liquid-crystalline, aqueous phase of a reactive dyestuff of the formula ##STR1## wherein M.sym. represents H.sym. or an alkali metal cation (preferably Na.sym., K.sym. or Li.sym.) and

Liquid-crystalline phase of an azo reactive dyestuff, and its use for

Leather dyeing agents, which can be obtained by concentrating, by means of a membrane separation process, the mother liquors, which are produced in the salting-out process in the preparation of organic dyestuffs which are water-soluble or which contain groups imparting water-solubility, the mother liquors having an extinction in the absorption maximum which is .gtoreq.500, with a layer thickness of 10 cm, and by drying the concentrate, if appropriate.

Leather dyeing agents and their preparation: membrame separation of dye

Highly concentrated liquid preparations of disperse dyestuffs are obtained with a low consumption of energy by first adding a dispersing agent to the water-moist dyestuff press-cake to convert it into a form in which it is capable of flow, subjecting this product to wet grinding and increasing the dyestuff content of the resulting, insufficiently concentrated dispersion in a second step by means of a membrane separation process, for example pressure permeation.

Process for producing liquid dyestuff preparations

Liquid finished formulations which are stable to storage and hydrolysis and are based on the lyotropic liquid crystal aqueous phase of the dyestuff of the formula ##STR1## which is present in water in a concentration of 23-35% at room temperature, are outstandingly suitable for the preparation of dyebaths and printing pastes for dyeing cotton, wool, regenerated cellulose, paper and leather.

Liquid crystal phase of an azo reactive dyestuff and its use for dyeing

Liquid finished formulations which are stable to storage and hydrolysis and are based on the lyotropic liquid crystal aqueous phase of the dyestuff of the formula ##STR1## in water in a concentration of 12-35% at room temperature are outstandingly suitable for the preparation of dyebaths and printing pastes for dyeing cotton, wool, regenerated cellulose, paper and leather.

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Odenthal, Germany

Jochen Koll