BigPatents India

A dye of the formula (I) wherein: each of R1, R2 R3 and R4, independently, is H or an optionally! substituted alkyl group; each of X1 and X2, independently, is a labile atom or group; each of x and y, independently, is 0 and 1 and at least one of x and y is 1; each of a and b, independently, is 2 to 5; z is zero or is 1 to 4; and when each of x and y is 1, a>b; the or each R5, independently, is alkyl; each of D1 and D2, independently, is a monoazo or polyazo chromophore, or a metallized derivative thereof, provided that the dye of the formula (I) is other than a dye of the formula (20)