Patent ID: 7198731

Claim:
A process for optically brightening a material, comprising the step of adding to the material a mixture, comprising compounds formula (I) wherein R 1 and R 2 are independently from each other H; halogen; unsubstituted C 1-6 alkyl; substituted C 1-6 alkyl or C 1-6 alkoxy, each (A) is independently from each other —O— or —NR 3 —, wherein R 3 is H; unsubstituted C 1-4 alkyl or substituted C 1-4 alkyl, X is halogen; OR 4 ; SR 4 or NR 4 R 5 , Y is halogen; OR 4 ; SR 4 or NR 4 R 5 , wherein R 4 is unsubstituted C 1-6 alkyl; substituted C 1-6 alkyl; unsubstituted phenyl or substituted phenyl, R 5 is H; unsubstituted C 1-6 alkyl or substituted C 1-6 alkyl, or R 4 and R 5 together with the nitrogen atom to which they are bonded form a pyrrolidinyl, piperidinyl or morpholinyl radical, n and m are independently from each other 0, 1 or 2 each M is a cation.