graft l m n copolymer______________________________________ m w 6 000 into a one liter separable flask equipped with a reflux condenser a thermometer a nitrogen blowing tube and a stirrer were added 200 parts of distilled water 100 parts of n butyl acrylate ba and a fluorine containing graft copolymer l synthesized in production example 23 in an amount of 0 05 part in terms of solid content under a nitrogen stream and in a constant stirring state 0 3 part of potassium persulfate kps as a polymerization initiator was added and the temperature of the reaction system was raised to 65 u00b0 c at which temperature polymerization was started then the reaction system was maintained at the temperature of 82 u00b0 c and the polymerization was accomplished in about 3 hours the polymer dispersion obtained was stable filtration of the dispersion with a 400 mesh metal net produced 0 8 part of agglomerate the particle diameter of the polymer particles obtained was 2 8 u03bc and the particle diameter distribution was almost monodisperse under the conditions in emulsion polymerization example 26 emulsion polymerization of ba was carried out by replacing the fluorine containing graft copolymer l with the fluorine containing graft copolymers m and n which were added respectively in an amount of 0 05 part in terms of.