Patent ID: 8163688

Claim:
A storage-stable aqueous fluorescent whitener formulation consisting essentially of (a) 10%-60% by weight, based on the total weight of the whitener formulation, of at least one compound of formula (1) wherein R 1 and R 2 are, independently from each other, hydrogen; unsubstituted C 1 -C 8 alkyl or substituted C 1 -C 8 alkyl, X 1 and X 3 are —NH 2 , X 2 and X 4 are, independently from each other, —N(R 3 )R 4 or —OR 5 , wherein R 3 and R 4 are, independently of each other, hydrogen; cyano; unsubstituted C 1 -C 8 alkyl; substituted C 1 -C 8 alkyl; unsubstituted C 8 -C 7 cycloalkyl or unsubstituted C 8 -C 7 cycloalkyl; or R 3 and R 4 , together with the nitrogen atom linking them, form a heterocyclic ring, and R 5 is unsubstituted C 1 -C 8 alkyl or substituted C 1 -C 8 alkyl, and M is hydrogen or a cation selected from the group consisting of Li, Na, K, Ca, Mg, ammonium, mono-, di, tri or tetra C 1 -C 4 alkylammonium, and mono, di- or tri-C 2 -C 4 -hydroxyalkylammoniuim, (b) 0.01-1% by weight, based on the total weight of the whitener formulation, of at least one anionic polysaccharide, (c) 0-25% by weight, based on the total weight of the whitener formulation, of at least one electrolyte, (d) 0-20% by weight, based on the total weight of the whitener formulation, of at least one dispersant, (e) 0-30% by weight, based on the total weight of the whitener formulation, of at least one further fluorescent whitener, (f) 0-20% by weight, based on the total weight of the whitener formulation, of at least one further optional component, and (g) water to make up 100% by weight.