Hyperbranched polymer having a nitroxyl group

The present invention provides a hyperbranched polymer having a nitroxyl group. A formula (1), equation (2), or Formula (3): [Formula 1] In formula includes an organic radical structure (nitroxyl radical) at least one is, the hyperbranched polymer is 5,000,000 to the 500 weight average molecular weight measured in terms of polystyrene by gel permeation chromatography. .BACKGROUND