Pigment dispersions containing dispersants prepared by controlled radical polymerization having hydrophilic and hydrophobic segments

Abstract

A pigment dispersion comprising pigment, an aqueous carrier selected from water and a mixture of water and at least one organic solvent, and a pigment dispersant is described. The pigment dispersant is prepared by controlled radical polymerization, e.g., atom transfer radical polymerization, and has polymer chain structure represented by the following general formula I, φ-(G)p-(E)s-T  I In general formula I, G is a residue of at least one radically polymerizable ethylenically unsaturated monomer; E is a hydrophilic residue of at least one radically polymerizable ethylenically unsaturated monomer; G and E are different from one another; φ is a hydrophobic residue of or derived from the initiator, and is free of said radically transferable group; T is or is derived from the radically transferable group of the initiator; p and s represent average numbers of residues occurring in a block of residues; p and s are each individually selected such that the pigment dispersant has a number average molecular weight of at least 250.

Dependencies are inferred from the claim text.