CONCENTRATED STORAGE-STABLE AQUEOUS OPTICAL BRIGHTENING SOLUTIONS Russian patent published in 2015 - IPC C07D251/54 C07D403/12 

FIELD: chemistry.

SUBSTANCE: invention relates to a concentrated storage-stable aqueous solution (S) comprising components (a), (b) and (c), wherein component (a) is at least one optical brightening agent of formula (1), in which the anionic charge on the brightener is balanced by a cationic charge composed of one or more cations selected from a group consisting of hydrogen, alkali metal cation, alkali-earth metal cation, ammonium, ammonium which is mono-, di- or trisubstituted by a C_1-4 linear or branched alkyl radical and ammonium which is mono-, di- or trisubstituted by a C_1-4 linear or branched hydroxyalkyl radical, and the concentration of component (a) is 0.08-0.3 mol/kg, based on the total weight of the concentrated storage-stable aqueous solution (S); component (b) is at least one inorganic salt (SA), in a concentration of 2-15 wt %, based on the total weight of the concentrated storage-stable aqueous solution (S), where the salts (SA) are preferably by-products of the production process and component (c) is water, in a concentration of 10-88 wt %, based on the total weight of the concentrated storage-stable aqueous solution (S).

EFFECT: invention relates to a method of producing a concentrated storage-stable aqueous solution (S), a method for use thereof as an optical brightening agent for bleaching cellulose substrates, fabrics or nonwoven materials, a sizing solution or suspension when processing paper and a pigmented coating composition containing the solution (S).

23 cl, 1 dwg, 7 tbl, 14 ex