Basf Se Corporation

Michael Jacquier

Allan Francis Cunningham

Rainer Hans Traber

Jacek Malisz

Heinz Schneider

Céline Hossenlopp

Johannes Nagel

Horst Herrmann

The present invention provides an improved process for isolating 2,4-bis-(2,4-dihydroxyphenyl)-6-(4-methoxyphenyl)-1,3,5-triazine (DIOPAT) from an aqueous alkaline mixture M having a pH of 10 or more and comprising the 2,4-bis-(2,4-dihydroxyphenyl)-6-(4-methoxyphenyl)-1,3,5-triazine, 2,4-dihydroxybenzophenone, and aluminum salts, wherein the process comprises a nanofiltration step, a precipitation step, and a further filtration step.

Removal of Al-salts, HCl, NaCl and organic by-product from strong alkaline DIOPAT suspension by means of alkaline stable nanofiltration followed by separation of salts and byproducts after neutralization of DIOPAT solution by means of ultrafiltration

The present invention relates to an aqueous direct dye formulation, comprising (a) 5 to 25% by weight of a dye composition comprising (a1) 50-99% by weight of one or more dyes obtainable by reduction or thermal treatment of Direct Yellow 11, and (a2) 1-50% by weight of a blue, black and/or red direct dye, (all based on the dye composition); (b) up to 0.9% by weight of a saturated, cyclic or acyclic water-soluble amine comprising a primary, secondary or tertiary amino group and at least one further functional group selected from primary, secondary and tertiary amino groups, OH groups and ether groups; and (c) up to 0.9% by weight of urea; and (d) water, wherein the percentages for (a), (b), and (c) relate to the total weight of the aqueous direct dye formulation. The invention moreover relates to a process for their preparation and the use thereof for the dyeing, in particular of paper, as well as paper which has been dyed with this aqueous direct dye formulation.

Aqueous direct dye formulations

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Binzen, Germany

Michael Jacquier