Patent ID: 8920605

Claim:
A composition suitable for optically whitening paper or board, comprising: at least two fluorescent whitening agents selected from the fluorescent whitening agents of formula (1), formula (2) and formula (3) wherein n and m are, independently of each other, 0, 1, or 2, with the proviso that n and m are not both 0; R 1 , R 2 , R 3 and R 4 represent, independently of each other, hydrogen, cyano, C 1 -C 4 alkyl, C 2 -C 4 hydroxyalkyl, C 2 -C 4 cyanoalkyl or C 1 -C 4 alkoxyalkyl, or the residue of an amino acid from which a hydrogen atom has been abstracted from the amino group; or R 1 and R 2 , or R 3 and R 4 , independently of each other, together with N atom form morpholine, piperidine or pyrrolidine ring; or —(CH 2 ) l —SO 3 M, where l is 1, 2 or 3; or —(CH 2 ) i —COOR, —(CH 2 ) i —CONHR, —(CH 2 ) i —COR, where i is an integer from 1 to 4, R is C 1 -C 3 alkyl or has the same meaning as M; M represents hydrogen, or one equivalent of a cation, in particular Li, Na, K, Ca, Mg, ammonium, or ammonium which is mono-, di-, tri- or tetra-substituted by C 1 -C 4 alkyl or C 2 -C 4 hydroxyalkyl.