Patent ID: 7060201

Claim:
An optical brightener (P AB ) of formula (I) wherein each n independently is 1 or 2, the group SO 3 M shown with the floating bond is linked to the position 4 or 5, each M independently is an equivalent of a non-chromophoric cation and each M′ independently is hydrogen or M, at least a part of the cations M of (P AB ) are cationic groups of a polycationic polyol/epichlorohydrin/amine polymer (P A ), containing quaternary ammonium groups in salt form as heteroatomic ring members or chain members, the remaining cations M of (P AB ) are selected from the group consisting of alkali metal cations, unsubstituted ammonium and ammonium substituted with C 1-3 -alkyl or/and C 2-3 -hydroxyalkyl, the polycationic polymer (P A ) is a polymer which is at least in part crosslinked over one or more of its quaternary ammonium groups, the remaining counterions to the cationic groups of (P A ) being non-chromophoric anions of low molecular acids, and the ratio of the total anionic groups in the anionic optical brightener portion of (P AB ) to the total of cationic ammonium groups in the polycationic polymer (P A ) portion of (P AB ) is ≧80/100.