Fluoroionomers dispersions having a low surface tension, low liquid viscosity and high solid content

Patent metadata

Field	Value
Publication number	US-9947952-B2
Application number	US-201615238385-A
Country	US
Kind code	B2
Filing date	Aug 16, 2016
Priority date	Jun 12, 2009
Publication date	Apr 17, 2018
Grant date	Apr 17, 2018

Abstract

The invention pertains to a process for manufacturing certain (per)fluoroionomer liquid compositions, comprising, inter alia, at least one of fluorination and treatment with a polar solvent, to the liquid compositions therefrom having an improved solids content/surface tension/liquid viscosity compromise, to the use of the same for manufacturing composite membranes and to composite membranes obtainable therefrom.

First claim

The invention claimed is:

1. An aqueous liquid composition having a surface tension of 15 to 30 mN/m, when determined at 25° C., said composition comprising:
at least one (per)fluoroionomer (I), in an amount of at least 9% wt, with respect to the total weight of the liquid composition;
at least one polar organic solvent (S′); and
water,
wherein said composition is a dispersion possessing a liquid viscosity when determined at 25° C. at a shear rate of 100 sec −1 , of:
less than 100 cP, when the (per)fluoroionomer (I) concentration is of at most 15% wt, with respect to the total weight of the liquid composition;
less than 150 cP, when the (per)fluoroionomer (I) concentration is of more than 15% wt and at most 30% wt, with respect to the total weight of the liquid composition;
less than 200 cP, when the (per)fluoroionomer (I) concentration is of more than 30% wt, with respect to the total weight of the liquid composition.

2. The aqueous liquid composition of claim 1 , wherein said (per)fluoroionomer (I) comprises recurring units derived from at least one fluorinated functional monomer selected from:
(M1) sulfonated perfluoroolefins of formula (M1):

wherein n is an integer between 0 and 6 and X′ is selected from the group consisting of halogens, wherein said halogens are selected from Cl, F, Br, and I,
—O − M + , wherein M + is a cation selected from the group consisting of H + , NH 4 + , K + , Li + , Na + , and mixtures thereof:
(M2) sulfonated perfluorovinylethers of formula (M2):

wherein m is an integer between 1 and 10 and X′ is selected from the group consisting of halogens, wherein said halogens are selected from Cl, F, Br, and I,
—O − M + , wherein M + is a cation selected from the group consisting of H + , NH 4 + , K + , Li + , Na + , and mixtures thereof;
(M3) sulfonated perfluoroalkoxyvinylethers of formula (M3):

wherein w is an integer between 0 and 2, RF 1 and RF 2 , equal or different from each other and at each occurrence, are independently —F, —Cl or a C 1-10 perfluoroalkyl group, optionally substituted with one or more ether oxygens, y is an integer between 0 and 6 and X′ is selected from the group consisting of halogens, wherein said halogens are selected from Cl, F, Br, and I, —O − M + , wherein M + is a cation selected from the group consisting of H + , NH 4 + , K + , Li + , Na + , and mixtures thereof;
(M4) perfluoroalkoxyvinylether carboxylates of formula (M4):

wherein w is an integer between 0 and 2, RF 1 and RF 2 , equal or different from each other and at each occurrence, are independently —F, —Cl or a C 1-10 perfluoroalkyl group, optionally substituted with one or more ether oxygens, y is an integer between 0 and 6, and R H§ is a C 1-10 alkyl or fluoroalkyl group;
(M5) sulfonated aromatic (per)fluoroolefins of formula (M5):

wherein Ar is a C 3-15 aromatic or heteroaromatic moiety and X′ is selected from the group consisting of halogens, wherein said halogens are selected from Cl, F, Br, and I, —O − M + , wherein M + is a cation selected from the group consisting of H + , NH 4 + , K + , Na + , and mixtures thereof; and
(M6) mixtures thereof.

3. The aqueous liquid composition of claim 2 , wherein said (per)fluoroionomer (I) is selected from TFE copolymers comprising:
from 5 to 30% by moles of recurring units derived from at least one monomer selected from perfluoro-2-(2-fluorosulfonylethoxy)propylvinyl ether (PSEPVE) of formula (M3-A):

 and
perfuoro-5-sulphonylfluoride-3-oxa-1-pentene (SFVE) of formula (M2-D):

in their —SO 2 F or —SO 2 X″ form, wherein X″ is selected from the group consisting of halogens, wherein said halogens are selected from Cl, Br, and I, —O − M + , wherein M + is a cation selected from the group consisting of H + , NH 4 + , K + , Li + , Na + , and mixtures thereof; and
from 95 to 70% by moles of recurring units derived from tetrafluoroethylene (TFE).

4. The aqueous liquid composition according to claim 1 , wherein solvent (S′) is selected from the group consisting of methanol, ethanol, 1-propanol, 2-propanol, 1-butanol, isobutanol, ethylene glycol and mixtures thereof.

5. A process for manufacturing a composite membrane, the process comprising contacting a porous support with the liquid composition according to claim 1 .

6. The process of claim 5 , wherein said process comprises a single impregnation step and is operated in continuum.

7. The process of claim 6 , said process comprising assembling the impregnated support onto a carrier film before submitting the same to the evaporation and annealing.

8. A composite membrane comprising:
a porous support; and,
a (per)fluoroionomer (I) impregnated therein, said (per)fluoroionomer having cation exchange groups of formula —SO 2 X, wherein X is selected from the group consisting of halogens, wherein said halogens are selected from Cl, F, Br, and I,
—O − M + , wherein M + is a cation selected from the group consisting of H + , NH 4 + , K + , Li + , Na + , and mixtures thereof,
wherein said composite membranes comprises two external peripheral regions essentially free from porous support, each of said peripheral regions having a first average thickness (T out ) and yielding, when analysed by Energy Dispersive X-Ray Spectroscopy (EDS), a first average intensity of the signal relative to sulphur (I S out ) and an inner region substantially comprising both porous support and (per)fluoroionomer (I), said inner region having a second average thickness (T in ) and yielding when analysed by EDS, a second average intensity of the signal relative to sulphur (I S in ),
wherein the ratio:

R
T

=

T
in

T
in

+

2
·

T
out

 is at least 0.3, and
wherein the ratio:

R
S

=

I
S
in

I
S
out

 is at least 0.4.

9. A composite membrane comprising:
a porous support; and,
a (per)fluoroionomer (I) impregnated therein, said (per)fluoroionomer having cation exchange groups of formula —SO

Assignees

• Solvay Specialty Polymers It

Inventors

• Merlo Luca
• Ghielmi Alessandro
• Arcella Vincenzo

Classifications

• H01M8/1039 Primary

  halogenated, e.g. sulfonated polyvinylidene fluorides · CPC title

• C08J5/2281

  fluorine containing heterogeneous membranes · CPC title

• H01M8/1025

  having only carbon and oxygen, e.g. polyethers, sulfonated polyetheretherketones [S-PEEK], sulfonated polysaccharides, sulfonated celluloses or sulfonated polyesters · CPC title

• B01J39/20

  obtained by reactions only involving unsaturated carbon-to-carbon bonds · CPC title

• C08J5/22

  Films, membranes or diaphragms · CPC title