| 摘要 |
A process for preparing peroxidic perfluoropolyethers having a peroxidic content (PO) higher than 1.2 of formula <?in-line-formulae description="In-line Formulae" end="lead"?>A-CF<SUB>2</SUB>O(CF<SUB>2</SUB>CF<SUB>2</SUB>O)<SUB>m</SUB>(CF<SUB>2</SUB>O)<SUB>n</SUB>-(CF<SUB>2</SUB>CF<SUB>2</SUB>OO)<SUP>ml</SUP>(CF<SUB>2</SUB>OO)<SUB>nl</SUB>CF<SUB>2</SUB>-B (I) <?in-line-formulae description="In-line Formulae" end="tail"?> wherein A, B, equal to or different from each other are Cl-, F-, C1CF<SUP>2</SUP>-, COF-, -OCOF, -CF<SUB>3</SUB>, m, ml, n, nl are integers such that the (m+ml)/(n+nl) ratio is between 0.9 and 5 and the m/n ratio is between 0.8 and 3, the number average molecular weight is in the range 35,000-45,000, by tetrafluoroethylene (TFE) photooxidation in the presence of UV light, at a temperature from -80° C. to -40° C., in the presence of a mixture of solvents formed of HFC-227 (heptafluoropropane) and a solvent selected from HFC-125 (pentafluoroethane) and FC-218 (perfluoropropane). |
