Patent ID: 9624329
Date: 2017-04-18
CPC Classifications: B01D,C08F

Claim:
1. A process for producing a fluorinated copolymer, the process comprising: (I) polymerizing a fluorinated monomer having a carboxylic acid functional group or a sulfonic acid functional group and a fluorinated olefin by a solution polymerization method in a polymerization medium to obtain slurry containing a fluorinated copolymer, an unreacted monomer and the polymerization medium; (II) continuously or intermittently transferring the slurry to an evaporation vessel provided with a stirrer and heating the slurry with stirring in the evaporation vessel under a pressure below atmospheric pressure to evaporate and recover the unreacted monomer and the polymerization medium, while keeping the fluorinated copolymer in the evaporation vessel; and (III) taking out the fluorinated copolymer from the evaporation vessel after finishing the recovery of the unreacted monomer and the polymerization medium, wherein a stirring blade in the evaporation vessel is a scraping blade which rubs against a wall surface of the evaporation vessel when rotating.