초록 ▼

A process for producing a fluorinated copolymer includes 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 a mixture containing a fluorinat

A process for producing a fluorinated copolymer includes 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 a mixture containing a fluorinated copolymer, an unreacted monomer and the polymerization medium. The mixture is continuously or intermittently transferred to an evaporation vessel provided with a stirrer and heating the mixture with stirring in the evaporation vessel to evaporate and recover the unreacted monomer and the polymerization medium.

대표청구항 ▼

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 co

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. 2. The process for producing a fluorinated copolymer according to claim 1, wherein the fluorinated monomer having a sulfonic acid functional group is a compound represented by the following formula (2) or (3): CF2═CF—O—Rf2-A2  (2)CF2═CF—Rf2-A2  (3) wherein Rf2 is a C1-20 perfluoroalkylene group, which may contain an etheric oxygen atom, and which may be linear or branched, and A2 is a sulfonic acid functional group. 3. The process for producing a fluorinated copolymer according to claim 1, wherein a stirring blade in the evaporation vessel is a helical ribbon blade. 4. The process for producing a fluorinated copolymer according to claim 1, wherein in the step (II), the slurry is transferred to the evaporation vessel so that the overall coefficient of heat transfer becomes at least 80 kJ/m2·h·° C. 5. The process for producing a fluorinated copolymer according to claim 1, wherein the amount of the unreacted monomer remaining is at most 1.0 mass % per 100 mass % of the fluorinated copolymer. 6. 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 bulk polymerization method to obtain slurry containing a fluorinated copolymer and an unreacted monomer;(II′) after the polymerizing of the fluorinated monomer and the fluorinated olefin is completed, 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, 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,wherein a stirring blade in the evaporation vessel is a scraping blade which rubs against a wall surface of the evaporation vessel when rotating. 7. The process for producing a fluorinated copolymer according to claim 6, wherein the fluorinated monomer having a sulfonic acid functional group is a compound represented by the following formula (2) or (3): CF2═CF—O—Rf2-A2  (2)CF2═CF—Rf2-A2  (3) wherein Rf2 is a C1-20 perfluoroalkylene group, which may contain an etheric oxygen atom, and which may be linear or branched, and A2 is a sulfonic acid functional group. 8. The process for producing a fluorinated copolymer according to claim 6, wherein a stirring blade in the evaporation vessel is a helical ribbon blade. 9. The process for producing a fluorinated copolymer according to claim 6, wherein in the step (II′), the slurry is transferred to the evaporation vessel so that the overall coefficient of heat transfer becomes at least 80 kJ/m2·h·° C. 10. The process for producing a fluorinated copolymer according to claim 6, wherein the amount of the unreacted monomer remaining is at most 1.0 mass % per 100 mass % of the fluorinated copolymer.