Patent ID: 6979716

Claim:
A production method of a branched polymer comprising performing living radical polymerization to obtain a macromonomer (I), said macromonomer (I) being a vinyl polymer terminally having one polymerizable carbon—carbon double bond-containing group per molecule, and polymerizing said macromonomer (I); wherein the macromonomer (I) has a weight average molecular weight (Mw)-to-number average molecular weight (Mn) ratio (Mw/Mn) of less than 1.8 as determined by gel permeation chromatography, wherein the polymerizable carbon—carbon double bond-containing group is represented by the general formula (1): —OC(O)C(R)═CH 2 (1) wherein R represents a hydrogen atom or a monovalent organic group containing 1 to 20 carbon atoms.