Removing fluorosurfactant from aqueous fluoropolymer dispersions using monodisperse ion exchange resin
View Patent ↗A process for reducing fluorosurfactant content of a stabilized fluorosurfactant-containing aqueous fluoropolymer dispersion comprising passing said stabilized fluorosurfactant-containing aqueous fluoropolymer dispersion through a fixed bed of ion exchange resin beads comprising a polymer and functional groups to reduce fluorosurfactant content, the ion exchange resin beads being monodisperse.
1. A process for reducing fluorosurfactant content of a stabilized fluorosurfactant-containing aqueous fluoropolymer dispersion comprising:
passing said stabilized fluorosurfactant-containing aqueous fluoropolymer dispersion through a fixed bed of ion exchange resin beads comprising a polymer and functional groups to reduce fluorosurfactant content, said ion exchange resin beads being monodisperse.
2. The process of claim 1 wherein said ion exchange resin beads have a number average size distribution in which 95% of the beads have a diameter within plus or minus 100 μm of the number average bead diameter.
3. The process of claim 1 wherein said ion exchange resin beads have a number average bead diameter of about 450 to about 800 μm.
4. The process of claim 1 wherein said ion exchange resin beads have a number average bead diameter of about 550 to about 700 μm.
5. The process of claim 1 wherein said stabilized dispersion has a solids content of at least about 25 wt %.
6. The process of claim 1 wherein said stabilized dispersion has a solids content of at least about 30 wt %.
7. The process of claim 1 wherein said stabilized dispersion has a solids content of at least about 35 wt %.
8. The process of claim 1 wherein said ion exchange resin comprises anion exchange resin.
9. The process of claim 8 wherein said functional groups of said resin are selected from the group comprising primary amine, secondary amine, tertiary amine, and quaternary ammonium groups.
10. The process of claim 8 wherein said anion exchange resin comprises quaternary ammonium groups.
11. The process of claim 8 wherein said anion exchange resin is in the hydroxide form.
12. The process of claim 1 wherein said passing of said stabilized fluorosurfactant-containing aqueous fluoropolymer dispersion through a fixed bed of ion exchange resin reduces fluorosurfactant content to a predetermined level of no greater than about 300 ppm.
13. The process of claim 1 wherein said passing of said stabilized fluorosurfactant-containing aqueous fluoropolymer dispersion through a fixed bed of ion exchange resin reduces fluorosurfactant content to a predetermined level of no greater than about 100 ppm.
14. The process of claim 1 wherein said passing of said stabilized fluorosurfactant-containing aqueous fluoropolymer dispersion through a fixed bed of ion exchange resin reduces fluorosurfactant content to a predetermined level of no greater than about 50 ppm.