Patent ID: 7566349

Claim:
A method of florescent whitening paper comprising contacting the paper with a fluorescent whitening mixture of compounds of formulae (1a), (1b) and (1c), in which A* represents a group of the formula wherein A represents —X—Y—NR 3 R 4 and C is —NR 1 R 2 and B* represents a group of the formula whereby the groups A* and B* are not identical, wherein D represents —NR 5 R 6 and E represents —X 1 —Y 1 —NR 7 R 8 , whereby X and X 1 each, independently of each other, represent —O— or —NH—, Y and Y 1 each, independently of each other, represent a straight-chain C 2 -C 8 alkylene or branched C 3 -C 8 alkylene chain, which may be interrupted by one or two nitrogen, oxygen or sulphur atoms or represent a 5- or 6-membered cycloaliphatic ring, R 1 , R 2 , R 5 and R 6 each independently of each other, represent hydrogen, C 1 -C 8 alkyl, C 2 -C 4 hydroxyalkyl, C 1 -C 4 alkoxyC 1 -C 4 alkyl, phenyl, which is unsubstituted or substituted by halogen, C 1 -C 4 alkoxy, C 1 -C 4 alkyl or sulphonamido, or R 1 and R 2 and/or R 5 and R 6 , together with the nitrogen atom to which they are attached, complete a morpholino- piperidino- or pyrrolidino-ring, R 3 , R 4 , R 7 and R 8 , each independently of each other, represent hydrogen, C 1 -C 4 alkyl, C 2 -C 4 hydroxyalkyl or R 3 and R 4 and/or R 7 and R 8 , together with the nitrogen atom to which they are attached, complete a morpholino-, piperidino- or pyrrolidino-ring and M represents hydrogen, an alkaline or alkaline earth metal, ammonium or alkylammonium.