A branched olefin
copolymer demonstrating excellent performance in various uses, comprising a building block (A) represented by formula (1) below and a building block (B) represented by formula (2) below, obtained by e.g. a method which involves sequentially conducting ( step 1) a step of synthesizing -group-containing olefin
copolymer (Q) containing at least one functional group (G) selected from a hydroxyl group, a
carboxylic acid group, an ester group, an amino group, an
epoxy group, a
silanol group and an
acid anhydride group, (step 2) a step of converting the functional group (G) into a group having an ability to initiate
radical polymerization, and (Step 3) a step of installing a
polymer segment (Z) by
radical polymerization of a
monomer essentially comprising a carbon-carbon
double bond-containing compound (R) containing at least one selected from an
oxygen atom, a
nitrogen atom, a
halogen atom and an
aryl group; wherein the formula (1), R<1 >represents a
hydrogen atom and a C1-18 linear or branched
aliphatic hydrocarbon group; in the formula (2), R<2 >represents a C1-18 linear or branched aliphatic or
aromatic hydrocarbon group; F represents a
heteroatom or a
heteroatom-containing linking group; Z represents a
polymer segment containing at least one selected from an
oxygen atom, a
nitrogen atom, a
halogen atom and an
aryl group and having a molecular-
weight distribution of 1.0 to 3.0; W represents a group selected from an alcoholic hydroxyl group, a phenolic hydroxyl group, a
carboxylic acid group, a
carboxylate group, an
acid anhydride group, an amino group, an
epoxy group, a siloxy group and a mercapto group; n is an integer of 1 to 3 and m is 0, 1 or 2 provided that when n is 2 or 3, Z may be the same or different to each other, and when m is 2, W may be the same or different to each other; and W may be bound to the same or different atom of R<1 >to form a cyclic structure.