E I du Pont de Nemours and Company has been granted a patent for an aqueous pigment dispersion comprised of at least one dispersed carbon black pigment, an aqueous carrier and at least one copolymer. The copolymer is prepared by polymerization of 10%-90% by weight of at least one macromonomer (1) having a terminal olefinic unsaturation in the presence of cobalt chain transfer agent, and 90%-10% by weight of a mixture of olefinically unsaturated monomers (2), wherein the percent by weight are based on the total amount of the copolymer and add up to 100% by weight, and wherein the at least one macromonomer (1) is comprised of 1a) 5%-100% by weight of at least one polymerized acid functional unsaturated monomer, 1b) optionally at least one polymerized hydroxy functional unsaturated monomer, 1c) and optionally at least one polymerized olefinically unsaturated monomer different from monomers 1a) and 1b), and wherein the mixture of olefinically unsaturated monomers (2) is comprised of 2a) 5%-80% by weight of at least one unsaturated vinyl aromatic monomer, 2b) 5%-50% by weight of at least one vinyl monomer with at least one polar heterocyclic group with a 5 or 6 membered ring, containing at leastone ring nitrogen atom which is not connected to a hydrogen atom, 2c) and optionally at least one olefinically unsaturated monomer different from monomers 2a) and 2b), wherein the percent
by weight of component 1a) are based on the total amount of macromonomer (1) and the percent by weight of components 2a, 2b and 2c are based on the total amount of the mixture of olefinically unsaturated monomers (2) and add up to 100% by weight.
