Process for manufacturing PVDF

Batch process or semi-continuous process for the manufacture of PVDF homopolymer or copolymer comprising the steps of:

• charging a polymerization reactor with water, the optional dispersing additive and optionally a paraffin wax;
• deaerating said reactor in order to remove the oxygen;
• heating said reactor to the chosen temperature and charging said reactor with the VDF and the optional monomer until the desired pressure is reached;
• introducing HFA161 as the transfer agent into the reactor either in total or partly at the start and partly during the polymerization;
• adding initiator in total or partly, in order to start the polymerization and the drop in pressure that results therefrom is compensated for by the addition of VDF and the optional comonomer;
• adding the optional remainder of the initiator during polymerization;
• and
• degassing the reactor after introducing the intended amount of VDF and optional comonomer, and separating the PVDF by any means from the water and the optional residues of the reactants involved.