Patent ID: 6864360

Claim:
Trisazo dye of the formula (I) or an alkali metal salt thereof; wherein: Ar 1 is an optionally substituted arylene group; Ar 2 is an optionally substituted aryl group; each of R 1 , R 2 , R 3 and R 4 , independently, is H, alkyl or phenyl; each of X 1 and X 2 , independently, is a labile atom or group; and each of D 1 and D 2 , independently, is a chromophore group of the formula wherein: Ar 3 is an aryl group; Y is a vinyl or allyl group or the group —CH 2 CH 2 V in which V is a leaving group; a is zero, 1, 2or3; b is zero, 1 or 2; at least one of a and b is at least 1; c is zero or 1 and when c is 1, the group SO 3 H on the naphthalene nucleus is substituted at the 5- or 6-position thereof; and the bond (1) is substituted at the 6-, or 7-position of the naphthalene nucleus.