Process for the high-pressure polymerization of 1, 1-difluoroethylene

A continuous process for the manufacture of PVDF homopolymer or copolymer, said process comprising:

• introducing a flow of VF2, optionally a comonomer comprising a vinyl group polymerizable by free radicals and at least one fluorine atom, a fluoroalkyl group or a fluoroalkoxy group directly attached to this vinyl group, and a radical initiator into a reactor maintained at a pressure of 300 bar-3000 bar, the reactor consisting essentially of VF2, optionally the comonomer, and PVDF;
• removing at least a portion of the reaction mixture form (a) and introducing into a separator;
• recovering molten PVDF in the separator and purging continuously;
• optionally introducing the flow of PVDF from (c) into a device to make granules;
• recovering VF2 and optionally the comonomer in the separator and recycling into (a);
• and
• deoxygenating fresh VF2 and optionally the comonomer before introduction into said reactor, the deoxygenating comprising placing the flow of VF2 and of the optional comonomer in contact with (i) a sufficient amount of a catalyst whose active sites are elements belonging to groups 8 to 11 of the Periodic Table and (ii) for a time sufficient to obtain the desired oxygen content.