Tough, stable tetrafluoroethylene-fluoroalkyl perfluorovinyl ether copolymers

Abstract

Tough, stable copolymers of tetrafluoroethylene monomer and fluorovinyl ether monomers can be produced by polymerizing the monomers in perfluorinated or suitable non-perfluorinated hydrogen and chlorine containing fluorocarbon solvents by a process that requires that the reaction be carried out at from about 30° to about 75° C. in the presence of a low temperature initiator such as bis(perfluoro propionyl) peroxide and a hydrogen containing chain transfer agent such as methanol.

I claim: 
     
       1. A process for forming a polymer of tetrafluoroethylene monomer and at least one fluorovinylether monomer copolymerizable therewith which comprises polymerizing tetrafluoroethylene with fluorovinyl ethers selected from the group consisting of (a) fluorovinyl ethers having the general formula   XCF.sub.2 (CF.sub.2).sub.n OCF═CF.sub.2       (b) fluorovinyl polyethers having the general formula ##STR5## where X=F or H and n=0-7, and (c) perfluoro-3,6-dioxa-4-methyl-7-octene sulfonyl fluoride, in a liquid solvent selected from the class consisting of (a) perfluorinated solvents (b) chlorofluoroalkanes in which each carbon atoms has at least one fluorine atom attached thereto and (c) chlorofluorohydroalkanes in which each carbon atom has at least one fluorine atom attached thereto and which may contain a maximum of one hydrogen atom per carbon atom if the hydrogen atom is present only in the difluoromethyl (CF 2  H) grouping, at a temperature in the range from 30° C. to about 75° C. and at pressures in the range of from about 15 to about 1000 p.s.i.g., in the presence of a hydrogen-containing chain transfer agent selected from the group consisting of methanol, isopropanol, and ethanol thereby to provide a copolymer having stable hydride end groups.     
     
     
       2. The process of claim 1 in which the solvent is selected from the group of solvents consisting of CCl 2  F 2 ,CCl 3  F, CClF 2  H, CCl 2  FCCl 2  F, CCl 2  FCClF 2 , and CClF 2  CClF 2   
     
     
       3. The process of claim 2 in which the chain transfer agent is methanol. 
     
     
       4. The process of claim 3 in which the solvent is CCl 2  FCClF 2 , the copolymerizable monomer is perfluoropropyl perfluorovinyl ether and the initiator is bis(perfluoropropionyl) peroxide. 
     
     
       5. The process of claim 4 in which the copolymerizable monomer is perfluoroethyl perfluorovinyl ether. .[.6. A tough, stable copolymer of tetrafluoroethylene with a fluoroalkylperfluorovinyl ether selected from the group consisting of (a) fluorovinyl ethers having the general formula XCF 2  (CF 2 ) n  OCF═CF 2  wherein X=F or H and n=1-7, (b) fluorovinyl polyethers having the general formula ##STR6## wherein X=F or H and n=0-7, and (c) perfluoro-3,6-dioxa-4-methyl-7-octene sulfonyl fluoride, said copolymer containing stable hydride end groups and having a volatiles index of less than 25, a swelling index of less than 25 and a melt viscosity from 1×10 4  -100×10 4  poises..]. 
     
     
        .[.7.  The product of claim 6 in which the fluoroalkyl perfluorovinyl ether is perfluoroethyl perfluorovinyl ether..]. .[.8. The product of claim 6 in which the fluoroalkyl perfluorovinyl ether is perfluoropropyl 
     
     
        perfluorovinyl ether..]. .Iadd.9.  A tough, stable copolymer of tetrafluoroethylene with perfluoropropyl perfluorovinyl ether, said copolymer containing stable hydride end groups and having a volatiles index of less than 25, a swelling index of less than 25 and a melt viscosity from 1×10 4  -100×10 4  poises. .Iaddend.