Liquid composition for proton exchange membranes

Patent metadata

Field	Value
Publication number	US-10446865-B2
Application number	US-201515520767-A
Country	US
Kind code	B2
Filing date	Oct 14, 2015
Priority date	Oct 20, 2014
Publication date	Oct 15, 2019
Grant date	Oct 15, 2019

Abstract

The present invention relates to a liquid composition comprising a polymer bearing —SO3H groups and a perfluoroelastomer, a method for manufacturing said liquid composition and an article manufactured by using said composition. Preferably, said article is a proton exchange membrane, which shows at the same time good mechanical resistance and electrochemical properties and is useful for example as separator in fuel cells.

First claim

The invention claimed is:

1. A composition (C) comprising:
a liquid medium (L);
at least one polymer [component (I)] comprising recurring units derived from at least one ethylenically unsaturated fluorinated monomer containing at least one —SO 3 Z group, wherein Z is H, an alkaline metal ion or NH 4 + [monomer (A)] and recurring units derived from at least one ethylenically unsaturated fluorinated monomer [monomer (B)]; and
at least one perfluoroelastomer [component (II)], wherein component (II) comprises recurring units derived from C 3 -C 8 perfluoroolefins and CF 2 ═CFOR f (per)fluoro-alkylvinylethers wherein R f is a C 1 -C 6 perfluoroalkyl group,

wherein the weight ratio between said component (I) and said component (II) is from 95/5 to 70/30.

2. The composition according to claim 1 , wherein said weight ratio between said component (I) and said component (II) is from 90/10 to 80/20.

3. The composition according to claim 1 , wherein said medium (L) comprises at least one medium selected from the group consisting of water, alcohols, high-boiling-point solvents selected from dimethylacetamide (DMA), dimethylformamide (DMF), dimethyl sulfoxide (DMSO), N-methyl-pyrrolidone (NMP), N-ethyl-pyrrolidone (NEP), and mixtures thereof.

4. The composition according to claim 1 , wherein said composition (C) comprises said component (I) in an amount of from 1 wt. % to 40 wt. % based on the total weight of said composition.

5. The composition according to claim 1 , wherein said composition (C) comprises said component (II) in an amount of from 0.05 wt. % to 18 wt. % based on the total weight of said composition.

6. The composition according to claim 1 , wherein said composition (C) comprises said component (I) and said component (II) in a total amount of from 5 wt. % to 45 wt. % based on the total weight of said composition.

7. The composition according to claim 1 , wherein said monomer (A) is selected from the group comprising:
CF 2 ═CF(CF 2 ) p SO 3 Z, wherein p is an integer between 0 and 10 and Z is H, an alkaline metal ion or NH 4 + ;
CF 2 ═CF—O—(CF 2 ) m SO 3 Z wherein m is an integer between 1 and 10 and Z is H, an alkaline metal ion or NH 4 + ;
CF 2 ═CF—(OCF 2 CF(R F1 )) w —O—CF 2 (CF(R F2 )) y SO 3 Z, wherein w is an integer between 0 and 2, R F1 and R F2 , equal or different from each other, are independently F, Cl or a C 1 -C 10 fluoroalkyl group, optionally substituted with one or more ether oxygens, y is an integer between 0 and 6, and Z is H, an alkaline metal ion or NH 4 + ; and
CF 2 ═CF—Ar—SO 3 Z wherein Ar is a C 5 -C 15 aromatic or heteroaromatic substituent, and Z is H, an alkaline metal ion or NH 4 + .

8. The composition according to claim 1 , wherein said monomer (B) is selected from the group comprising:
C 2 -C 8 fluoroolefins;
vinylidene fluoride;
C 2 -C 8 chloro- and/or bromo- and/or iodo-fluoroolefins;
fluoroalkylvinylethers of formula CF 2 ═CFOR f1 , wherein R f1 is a C 1 -C 6 fluoroalkyl;
CF 2 ═CFOR O1 , wherein R O1 is a C 1 -C 12 fluoro-oxyalkyl having one or more ether groups;
CF 2 =CFOCF 2 OR f2 in which R f2 is a C 1 -C 6 fluoroalkyl or a C 1 -C 6 fluorooxyalkyl having one or more ether groups;
fluorodioxoles of formula:

wherein each of R f3 , R f4 , R f5 , R f6 , equal or different each other, is independently a fluorine atom, a C 1 -C 6 fluoro(halo)fluoroalkyl, optionally comprising one or more oxygen atom.

9. The composition according to claim 1 , wherein component (I) further comprises recurring units derived from bis-olefin.

10. The composition according to claim 9 , wherein said bis-olefin is selected from the group comprising:
R 1 R 2 C═CH—(CF 2 ) j —CH═CR 3 R 4 wherein j is an integer between 2 and 10, and R 1 , R 2 , R 3 , R 4 , equal or different from each other, are —H, —F or C 1 -C 5 alkyl or (per)fluoroalkyl group;
A 2 C═CB—O-E-O—CB=CA 2 , wherein each of A, equal or different from each other, is independently selected from —F, —Cl, and —H; each of B, equal or different from each other is independently selected from —F, —Cl, —H and —OR B , wherein R B is a branched or straight chain alkyl radical which is optionally partially or completely fluorinated or chlorinated; E is a divalent group having 2 to 10 carbon atoms, optionally fluorinated, which optionally includes ether linkages; and
R 6 R 7 C═CR 5 -E-O—CB=CA 2 , wherein E, A and B have the same meaning as above defined; R 5 , R 6 , R 7 , equal or different from each other, are —H, —F or C 1 -C 5 alkyl or fluoroalkyl group.

11. A method for manufacturing composition (C) according to claim 1 , said method comprising:
(i) providing a composition (C1) comprising component (I) in a first liquid medium (I);
(ii) diluting said composition (C1) with a liquid medium (d), so as to obtain a diluted composition (dC1) in a diluted liquid medium (dI) comprising said component (I) in an amount of less than 10 wt. % with respect to the total weight of said composition (dC1);
(iii) mixing said composition (dC1) with a composition (C2) comprising component (II) in a second liquid medium (II), so as to provide a diluted mixed composition (dC3) in a third liquid medium (III) comprising a weight ratio between said component (I) and said component (II) of from 95/5 to 70/30, and
(iv) removing a portion of said medium (III) from said composition (dC3), so as to provide composition (C) comprising medium (L), component (I) and component (II), wherein said component (I) and said component (II) are in an amount of at least 15 wt. % based on the total weight of said composition.

12. The method according to claim 11 , wherein said weight ratio between said component (I) and said component (II) is from 90/10 to 80/20.

13. An article comprising composition (C) according to claim 1 .

14. A method for manufacturing a proton exchange membrane, said method comprising:
(A) casting composition (C) according to claim 1 to obtain a film or impregnating said composition (C) onto a porous support to obtain an impregnated support;
(B) removing medium (L) from said film to obtain a dried film or from said impregnated support to obtain a dried impregnated support; and
(C) heating said dried film or said dried impregnated support at a temperature between 140° C. and 230° C. to obtain a proton exchange membrane.

15. The composition according to claim 10 , wherein j is an integer between 4 and 8.

16. The composition according to claim 10 , wherein E is a —(CF 2 ) z — group, with z being an integer from 3 to 5.

17. The composition according to claim 1 , wherein component (II) comprises recurring units derived from tetrafluoroethylene (TFE) and perfluoromethyl-vinyl-ether (MVE).

18. The article according to claim 13 , wherein said article is a proton exchange membrane.

Assignees

• Solvay Specialty Polymers It

Inventors

• Merlo Luca
• Tonella Stefano
• Corasaniti Martina
• Oldani Claudio

Classifications

• H01M8/1044 Primary

  Mixtures of polymers, of which at least one is ionically conductive · CPC title

• H01M8/1081

  starting from solutions, dispersions or slurries exclusively of polymers · CPC title

• C09D127/18 Primary

  Homopolymers or copolymers of tetrafluoroethene · CPC title

• C08J2327/22

  modified by chemical after-treatment · CPC title

• C08J2327/18

  Homopolymers or copolymers of tetrafluoroethylene · CPC title