Patent ID: 7420017

Claim:
A process for preparing a fluorine containing copolymer by an emulsion polymerization method in the presence of a pH modifier wherein the pH modifier is aqueous ammonia and wherein a coagulating agent comprising a cationic surfactant and a water soluble organic solvent is used in the preparation of the fluorine containing copolymer by coagulating a fluorine containing copolymer in a fluorine containing copolymer dispersed aqueous solution prepared by the emulsion polymerization method, the said cationic surfactant represented by the following formula: (R 4 N + )X − wherein R is any one of an alkyl group of 1 to 22 carbon atoms, a fluoroalkyl group and a hydrogen atom, four R's may be the same or different, provided that four R's are not hydrogen atoms simultaneously, and X is a halogen atom.