Patent ID: 7795347

Claim:
A multi-branched polymer comprising at least one block structure or graft structure represented by the following general formula (II): (P 2 )(P 3 )—X 1 (II) wherein P 2 is a polar polymer chain having polyolefin side chains (A4) and said P 2 has a number-average molecular weight (Mn) of 500 to 1,000,000, and P 3 is a polymer chain having a number-average molecular weight (Mn) of 500 to 1,000,000, selected from a polyolefin chain having polar polymer side chains (A2), a polar polymer chain (A3) and a polar polymer chain having polyolefin side chains (A4); P 2 and P 3 may be the same or different from each other; X 1 is a linking group containing less than 200 atoms in total and containing a group selected from an ester group, an amide group and an ether group.