To obtain a water-based pigment dispersion low in viscosity even in high pigment concentrations and excellent in color developability.
The subject method for producing a pigment-dispersed resin 3,000-50,000 in Mw (weight-average molecular weight) and 10-200 mgKOH/g in resin acid value involves (A) a step wherein methacrylic acid is copolymerized with at least one copolymerizable monomer selected from methacrylic esters and styrene in the presence of a metal complex or addition cleavage-type chain transfer agent as a catalytic chain transfer agent and, ad necessary a radical polymerization initiator to obtain a macromonomer 50-450 mgKOH/g in acid value, and as necessary, a 2nd step wherein the macromonomer is esterified to introduce a polymerizable unsaturated group thereinto and (B) the subsequent step wherein a copolymerization between the above macromonomer into which the polymerizable unsaturated group is introduced optionally and an ethylenically unsaturated monomer is conducted in the presence of a radical polymerization initiator. The other objective pigment dispersion is obtained by the use of the above pigment-dispersed resin. A coating composition is obtained by the use of the above pigment dispersion.
YUGAWA YOSHIYUKI
KAMIMORI ISAO
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