PROCESS FOR PRODUCTION OF POLYVINYLIDENE FLUORIDES Russian patent published in 2002 - IPC

FIELD: polymer production. SUBSTANCE: invention relates to production of high-purity polyvinylidene fluorides, which can be used where demands for purity of utilized components (drugs, makeup preparations) are made. Polyvinylidene fluorides are prepared by polymerization of vinylidene fluoride with one or more fluorine-containing comonomers in presence of (i) microemulsion of (per)fluoropolyethers having neutral end groups or hydrogen-containing recurrent motifs, wherein said fluoropolyethers have average molecular weight from 400 to 3000, and (ii) surfactant based on perfluoroethers with end groups in the form of carboxylic acid salts. Polyvinylidene fluorides have molecular weight between 400 and 600 and molecular weight distribution such that fractions having molecular weight superior to 700 are absent or present in quantities below 5 wt %. Products show high white index at low level of impurities. EFFECT: improved quality of products. 12 cl, 3 tbl, 3 ex