ABATEMENT OF FLUOROETHER CARBOXYLIC ACIDS OR SALTS EMPLOYED IN FLUOROPOLYMER RESIN MANUFACTURE

摘要

A process for making fluoropolymer resin comprising polymerizing at least one fluorinated monomer in an aqueous medium containing initiator and polymerization agent comprising fluoroether carboxylic acid or salt thereof to form an aqueous dispersion of particles of fluoropolymer. The fluoroether carboxylic acid or salt thereof employed in the process has the formula:;[R1—O-L-COO−]Y+;wherein R1 is a linear, branched or cyclic partially or fully fluorinated aliphatic group which may contain ether linkages; L is a branched partially or fully fluorinated alkylene group which may contain ether linkages; and Y+ is hydrogen, ammonium or alkali metal cation. Wet fluoropolymer resin is isolated from the aqueous medium. The wet fluoropolymer resin is to produce a dry fluoropolymer resin and to decarboxylate the residual fluoroether carboxylic acid or salt to produce a vapor of fluoroether byproduct. The vapor of fluoroether byproduct is captured.

主权项

1. A process for recovering hydrofluoroether of the formula:
CF3—CF2—CF2—O—(—CFCF3—CF2—O—)n—CFHCF3 wherein n is 0-35, as a byproduct in a process for making fluoropolymer resin comprising:
polymerizing at least one fluorinated monomer in an aqueous medium containing initiator and polymerization agent comprising fluoroether carboxylic acid or salt thereof to form an aqueous dispersion of particles of fluoropolymer, said fluoroether carboxylic acid or salt thereof having the formula:
[CF3—CF2—CF2—O—(—CFCF3—CF2—O—)n—CF(CF3)—COO−]Y+ wherein:
n is 0-35; andY+ is hydrogen, ammonium or alkali metal cation;isolating wet fluoropolymer resin containing residual fluoroether carboxylic acid or salt from said aqueous medium;heating said wet fluoropolymer resin to remove water to produce a dry fluoropolymer resin and to decarboxylate said residual fluoroether carboxylic acid or salt to produce a vapor of hydrofluoroether;capturing said vapor of hydrofluoroether; andrecovering said hydrofluoroether.