초록 ▼

A polymerization process in aqueous emulsion of: (I) one or more fluorinated monomers containing at least one ethylene unsaturation; (II) one or more fluorinated monomers, containing sulphonyl groups --SO2F; said process comprising the use of a surfactant having the formula: Rf--X-M+ wherei

A polymerization process in aqueous emulsion of: (I) one or more fluorinated monomers containing at least one ethylene unsaturation; (II) one or more fluorinated monomers, containing sulphonyl groups --SO2F; said process comprising the use of a surfactant having the formula: Rf--X-M+ wherein X is equal to --COO, --SO3; M is selected from H, NH4,alkaline metal; Rfrepresents a (per)fluoropolyether chain, preferably having number average molecular weight comprised between about 230 and about 1,800.

대표청구항 ▼

1. A polymerization process in aqueous emulsion of: (I) one or more fluorinated monomers containing at least one ethylene unsaturation; (II) one or more fluorinated monomers containing sulphonyl groups --SO2F; said process comprising: reactor purging, monomer (II) introduction in liquid form

1. A polymerization process in aqueous emulsion of: (I) one or more fluorinated monomers containing at least one ethylene unsaturation; (II) one or more fluorinated monomers containing sulphonyl groups --SO2F; said process comprising: reactor purging, monomer (II) introduction in liquid form into the reactor, reactor pressurization with gaseous monomers (I); addition of at least one surfactant of formula: Rf--X-M+ wherein: X is equal to --COO, --SO3; M is selected from H, NH4,alkaline metal; Rfrepresents a (per)fluoropolyether chain, preferably having number average molecular weight comprised between about 230 and about 1,800, preferably from 300 to 750, said (per)fluoropolyether chain comprising repeating units selected from one or more of the following: a) --(C3F6O)--; b) --(CF2CF2O)--; c) --(CFL0O)--, wherein L0=--F, --CF3; d) --CF2(CF2)z'CF2O--, wherein z' is an integer 1 or 2; e) --CH2CF2CF2O--; Rfis monofunctional, and has a (per)fluorooxyalkyl end group T, optionally in the (per)fluoroalkyl end groups one fluorine atom is substituted by one chlorine or hydrogen atom; addition of the initiator, and during the polymerization feeding of monomers (I) so as to maintain constant the reactor pressure; optionally further addition of monomer (II) and chain transfer agents. 2. A process according to claim 1, wherein the monomer (II) is added by steps. 3. A process according to claim 1, wherein Rfhas one of the following structures: 1) T--(CF2O)a--(CF2CF2O)b--CF2with b/a comprised between 0.3 and 10, extremes included, a being an integer different from 0; 2) T--(CF2--(CF2)z'--CF2O)b'--CF2wherein z' is an integer equal to 1 or 2; 3) T--(C3F6O)r--(C2F4O)b--(CFL0O)t--CF2-- with r/b=0.5-2.0 (r+b)/t=10-30, b and t being integers different from 0 when all the units with indexes r, b, and t are present; or b=t=0, or b=0; a, b, b', r, t, are integers, whose sum is such that Rfhas the above values of number average molecular weight. 4. A process according to claim 1, wherein the fluorinated monomers of type (I) are selected from: vinylidene fluoride (VDF); C2-C8perfluoroolefins, preferably tetrafluoroethylene (TFE); C2-C8chloro- and/or bromo- and/or iodo-fluoroolefins, such as chlorotrifluoroethylene (CTFE) and bromotrifluoroethylene; (per)fluoroalkylvinylethers (PAVE) CF2=CFORf,wherein Rfis a C1-C6(per) fluoroalkyl, for example trifluoromethyl, bromo difluoromethyl, pentafluoropropyl; perfluoro-oxyalkylvinylethers CF2=CFOX,wherein X is a C1-C12perfluorooxyalkyl having one or more ether groups, for example perfluoro-2-propoxy-propyl; the fluorinated monomers of type (II) are selected from: F2C=CF--O--CF2--CF2--SO2F (vinylsulphonylfluoride); F2C=CF--O--[CF2--CXF--O]n--CF2--CF2--SO2F wherein X=Cl, F or CF3; n=1-10;