Emulsifier for emulsion polymerization, production method of polymer emulsion and polymer emulsion

A reactive emulsifier for emulsion polymerization that does not have a polyoxyalkylene chain as a hydrophilic group, has good stability at the time of emulsion polymerization, and gives a polymer and a polymer film, having greatly improved various properties such as water resistance, adhesion, heat resistance and weather resistance is disclosed. The emulsifier for emulsion polymerization includes a compound represented by the following formula (1): wherein R 1 represents a substituent represented by R or -CH 2 -O-R wherein R represents a hydrocarbon group; R 2 represents a hydrogen atom or a methyl group; n represents from 1 to 200; X 1 and X 2 each represents a hydrogen atom, a hydrocarbon group or an anionic hydrophilic group.