Pigment dispersions containing dispersants having pendent hydrophobic polymeric segments prepared by controlled radical polymerization

A pigment dispersion comprising:

• (a) pigment;
• (b) an aqueous carrier selected from water and a mixture of water and at least one organic solvent;
• and
• (c) a pigment dispersant prepared by polymerizing a composition comprising,
• (i) at least one prepolymer having a radically polymerizable group, said prepolymer being prepared by controlled radical polymerization of at least one radically polymerizable ethylenically unsaturated first monomer, said prepolymer having a polydispersity index of less than 2.0;
• and
• (ii) at least one radically polymerizable ethylenically unsaturated second monomer to produce a polymer backbone segment in said pigment dispersant;
• wherein said prepolymer after polymerization with (c)(ii) is in the form of polymeric segments pendent to said polymeric backbone segment, at least a portion of each pendent polymeric segment is hydrophobic, and said polymeric backbone segment is hydrophilic;
• wherein each of said first and second monomers are independently selected from vinyl monomers, allylic monomers, olefins and mixtures thereof and each pendant polymeric segment of said pigment dispersant contains residues of monomers selected independently from the group consisting of:
• oxirane functional monomer reacted with a carboxylic acid selected from the group consisting of aromatic carboxylic acids, polycyclic aromatic carboxylic acids, aliphatic carboxylic acids having from 6 to 20 carbon atoms and mixtures thereof;
• C1 to C20 alkyl (meth)acrylates;
• aromatic methacrylates;
• polycyclicaromatic (meth)acrylates;
• vinyl esters of carboxylic acids;
• N,N-di(C1 to C8 alkyl) (meth)acrylamides;
• maleimide;
• N—(C1 to C20 alkyl)maleimides;
• N—(C3 to C8 cycloalkyl)maleimides;
• N—(aryl)maleimides;
• and mixtures thereof.