Process for making a fluoropolymer dispersion

Patent metadata

Field	Value
Publication number	US-2022073721-A1
Application number	US-201917291002-A
Country	US
Kind code	A1
Filing date	Nov 6, 2019
Priority date	Nov 12, 2018
Publication date	Mar 10, 2022
Grant date	—

Abstract

The invention relates to a process to produce a stable fluoropolymer latex using non-fluorinated surfactant with greater thermal stability. The polymerization is run at pressures greater than typically used. The resulting polymer exhibit improved melt color stability as compared to those produced under similar conditions at lower pressures.

First claim

What is claimed is:

1 . A process for forming a stable fluoropolymer emulsion, comprising polymerizing in a reactor, one or more fluoromonomers in an aqueous medium comprising initiator, optionally fluorine-free surfactant, and running the polymerization at a pressure of greater than 800 psi; and wherein the surfactant comprises a non-fluorinated non-ionic emulsifiers containing segments of at least one of polyethylene glycol (PEG), polypropylene glycol (PPG), polytetramethylene glycol (PTMG) or a combination thereof, with repeating units between 2 to 200, preferably between 3 to 100, and more preferably 5 to 50.

2 . The process of claim 1 , wherein the pressure during polymerization is greater than 1000 psi.

3 . The process of any one of claim 1 or 2 , wherein the pressure during polymerization is at least 1100 psi, preferably at least 1150 psi, more preferably at least 1200 psi.

4 . The process of claim 1 , wherein the pressure during polymerization is from greater than 1000 psi to 2500 psi.

5 . The process of claim 4 , wherein the pressure during polymerization is from at least 1100 psi to 2000 psi.

6 . The process of any one of claims 1 to 5 , wherein the surfactant comprises at least one surfactant selected from the group consisting of polyethylene glycol acrylate (PEGA), polyethylene glycol methacrylate (PEG-MA), dimethyl polyethylene glycol (DMPEG), polyethylene glycol butyl ether (PEGBE), polyethylene glycol (PEG), polyethylene glycol phenol oxide (Triton X-100), polypropylene glycol acrylate (PPGA), polypropylene glycol (PPG) polypropylene glycol acrylate (PPGA), polypropylene glycol methacrylate (PPG-MA), and polytetramethylene glycol (PTMG).

7 . The process of any one of claims 1 to 5 , wherein the surfactant comprises an emulsifier of Formula 1:
Ti-[(CH 2 —CH 2 —O—) X ] m —[(CH 2 —CH(CH 3 )—O—) Y ] n —[(CH 2 —CH 2 —O—) Z ] k -T 2   (Formula 1)

where X, Y, and Z are between 2 to 200; and m, n, k are from 0 to 5, wherein at least one of m, n and k are greater than 0 and T 1 and T 2 are terminal groups such as hydrogen, hydroxyl, carboxyl, ester, ether and/or hydrocarbon.

8 . The process of any one of claims 1 to 5 , wherein the surfactant comprises a triblock copolymer, preferably having a PEG central block and PPG endblocks.

9 . The process of any one of claims 1 to 8 , wherein said non-fluorinated, non-ionic emulsifier(s) is present in the process at from 0 to 1 percent, preferably 100 ppm to 1 percent, based on the weight of the fluoropolymer solids.

10 . The process of any one of claims 1 to 5 , wherein no surfactant is added during the polymerization.

11 . The process of any one of claims 1 to 10 , wherein the fluoromonomers are one or more fluoromonomers selected from the group consisting of vinylidene fluoride, tetrafluoroethylene, trifluoroethylene, chlorotrifluoroethylene, hexafluoropropene, vinyl fluoride, 1,1,1,3,3-pentafluoropropene, 1,1,1,3,3,3-hexafluoroisobutylene, 1,1,1,2-tetrafluoropropene, 1,1,1-trifluoropropene, 1,1,1,3-tetrafluoropropene, 1,1,1,2,3-pentafluoropropene, perfluoromethyl vinyl ether, perfluroethyl vinyl ether, and perfluoropropyl vinyl ether.

12 . The process of any one of claims 1 to 11 , wherein said fluoropolymer contains at least 50 mole percent vinylidene fluoride monomer units.

13 . The process of any one of claims 1 to 12 , wherein said fluoropolymer contains from 70 to 100 mole percent vinylidene fluoride monomer units and the level of one or more other fluoromonomers is from 0 to 30 mole percent.

14 . The process of any one of claims 1 to 13 , further comprising from 100 ppm to 10,000 ppm of one or more ionic or ionizable initiators.

15 . The process of any one of claims 1 to 14 , wherein said initiator(s) comprise at least one or more initiators selected from the group consisting of ammonium persulfate, alkali metal salts of persulfates, dialkyl peroxides, diacylperoxides, peroxyesters, and peroxydicarbonates, preferably ammonium or alkali metal salts of persulfate.

16 . The process of any one of claims 1 to 15 , wherein the solids level in the stable emulsion produced is at least 33.5 weight percent, preferably greater than 34 weight percent, preferably greater than 35 weight percent, preferably greater than 36 weight percent, more preferably greater than 37 weight percent, of fluoropolymer solids.

17 . The process of any one of claims 1 to 16 , wherein the solids level in the stable emulsion produced is at least 33.5 to 50 weight percent, or from greater than 34 to 45 weight percent solids, and more preferably from 35 to 45 weight percent, more preferably from 36 to 45 weight percent, more preferably from 37 to 45 weight percent, of fluoropolymer solids.

18 . The process of any one of claims 1 to 17 , wherein the surfactant is not added until after initiation of the polymerization reaction.

19 . The process of any one of claims 1 to 17 , wherein at least part of the surfactant is added prior to initiation of the polymerization reaction.

20 . The process of any one of claims 1 to 19 , wherein the YI of the polymer is 20 or less.

21 . A polymer produced from the process of any one of claims 1 to 20 .

22 . The polymer of claims 21 , further comprising at least one additive selected from the group consisting of dyes, colorants, impact modifiers, antioxidants, flame-retardants, ultraviolet stabilizers, flow aids, conductive additives such as metals, carbon black and carbon nanotubes, defoamers, cross-linkers, waxes, solvents, plasticizers, and anti-static agents.

Assignees

• Arkema Inc

Inventors

• Goldbach James T
• Bonnet Anthony
• Kahn Andrew P

Classifications

• C08F6/20

  Concentration · CPC title

• C08F14/22

  Vinylidene fluoride · CPC title

• C08F114/22

  Vinylidene fluoride · CPC title

• C08F4/40 Primary

  Redox systems · CPC title

• C08L2201/52

  Aqueous emulsion or latex, e.g. containing polymers of a glass transition temperature (Tg) below 20°C · CPC title