Patent ID: 6336966
Filing Date: 2002-01-08
Classification: C08F,C09B,C09D

Abstract:
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) at least one pigment dispersant prepared by atom transfer radical polymerization of a polymerizable composition selected from, (i) a prepolymer having a radically transferable group, and a polyfunctional monomer having at least two radically polymerizable ethylenically unsaturated groups, said prepolymer being prepared by atom transfer radical polymerization of at least one first monomer having a single radically polymerizable ethylenically unsaturated group in the presence of a monomeric initiator having at least one radically transferable group selected from the group consisting of linear aliphatic compounds, branched aliphatic compounds cycloaliphatic compounds, aromatic compounds, polycyclic aromatic compounds, heterocyclic compounds, sulfonyl compounds, sulfenyl compounds, esters of carboxylic acids, nitrites, ketones and mixtures thereof; (ii) a star polymer having a plurality of radically transferable groups, and at least one second monomer having a single radically polymerizable ethylenically unsaturated group, said star polymer being prepared by the atom transfer radical polymerization of said prepolymer and said polyfunctional monomer, said first and second monomers being the same or different; (iii) a core initiator having a plurality of radically transferable groups, and said first monomer, said core initiator being prepared by atom transfer radical polymerization of said polyfunctional monomer in the presence of said monomeric initiator; and (iv) said first monomer and said polyfunctional monomer in the presence of said monomeric initiator; wherein upon the atom transfer radical polymerization of said polymerizable compositions said polyfunctional monomer or said core initiator forms substantially a core segment of said pigment dispersant, and said prepolymer or at least one of said first and second monomers forms substantially a plurality of arm segments of said pigment dispersant, each of said arm segments having hydrophobic and hydrophilic polymer chain segments, said monomeric initiator being part of said hydrophobic segment.