Non-dewetting porous membranes

Patent metadata

Field	Value
Publication number	US-9359480-B2
Application number	US-201013262743-A
Country	US
Kind code	B2
Filing date	Mar 31, 2010
Priority date	Apr 6, 2009
Publication date	Jun 7, 2016
Grant date	Jun 7, 2016

Abstract

Microporous membrane composites that are non-dewetting are disclosed. These microporous membrane composites are wet with solutions of methanol and water and are non-dewetting following autoclave treatment in water. The microporous membrane composites comprise a microporous membrane support that is coated with a crosslinked ionomer comprising hydrophilic groups. Compared to the microporous membrane support, the microporous membrane composite has a flow loss on average in isopropyl alcohol of less than 82%.

First claim

What is claimed is:

1. A fluorocarbon liquid composition comprising a fluorocarbon liquid medium containing a fluorinated ionomer dissolved or dispersed therein, the fluorinated ionomer having iodine and/or bromine atoms at a terminal position, at least 90% by weight of the fluorinated ionomer consisting in particles of size lower than 200 nm, wherein the fluorinated ionomer comprises units from copolymerization of:
i) tetrafluoroethylene;
ii) fluorinated monomer units containing ethylenic groups and functional groups chosen from —SO 2 F, —COOR, —COF or combinations of these, wherein R is a C 1 to C 20 alkyl radical or a C 6 to C 20 aryl radical;
iii) monomeric units deriving from a bis-olefin, chosen from formulae (OF-1), (OF-2), or (OF-3) where:

wherein j is an integer between 2 and 10, and R1, R2, R3, R4, individually equal or different from each other, are H, F or C 1 to C 5 alkyl or (per)fluoroalkyl group;

wherein each of A, equal or different from each other and at each occurrence, is independently F, Cl, or H; each of B, equal or different from each other and at each occurrence, is independently F, Cl, H or ORB, wherein RB is a branched or straight chain alkyl radical which can be partially, substantially or completely fluorinated or chlorinated; E is a divalent group having 2 to 10 carbon atom, optionally fluorinated, which may be inserted with ether linkages;

wherein E, A and B have the same meaning as above defined; R5, R6, R7, independently equal or different from each other, are H, F or C1-5 alkyl or (per)fluoroalkyl group; and
iv) a compound having the formula R f (I) x (Br) y , wherein where R f is a fluoroalkyl or (per)fluoroalkyl or a (per)fluorochloroalkyl group having from 1 to 8 carbon atoms, and wherein x and y are integers from 0 to 2, with 1≦x+y≦2;
wherein the fluorocarbon liquid medium comprises a mixture of perfluoropolyethers, said perfluoropolyethers having the general formula F 3 C—O—[CF 2 —CF(CF 3 )—O] n —[CF 2 —O] m —CF 3 wherein m and n are integers, being n>0 and m≧0, said perfluoropolyethers having molecular weight between 300 atomic mass units (amu) and 600 amu, said mixtures having prevailing average boiling points between 55° C. and 135° C. and an average ratio between the indexes m and n (m/n) below 0.05;
wherein the fluorinated ionomer has an equivalent weight of between 380 g/eq and 620 g/eq; and
wherein the concentration of fluorinated ionomer in the fluorocarbon liquid composition range from 0.1 weight percent to 4 weight percent.

2. The liquid composition of claim 1 , wherein the content of the iodine and/or bromine atoms is between 0.1% and 5% by weight based on the ionomer.

3. The liquid composition of claim 1 wherein the liquid composition contains mixtures of perfluoropolyethers having the general formula F 3 C—O—[CF 2 —CF(CF 3 )—O] n —[CF 2 —O] m —CF 3 , each perfluoropolyether having molecular weight between 400 and 600 amu, said mixture having a prevailing (“average”) boiling point comprised between 80° C. and 100° C. and an average ratio between the indexes m and n (m/n) below 0.05.

4. The liquid composition according to claim 1 wherein the fluorocarbon liquid medium further comprises a hydrogenated fluoropolyether or a mixture of hydrogenated fluoropolyethers (HFPE) having the general formula R*—O—R f ′—R*′ wherein:
—R* and R*′, equal or different from each other, are independently chosen between —C m F 2m+1 and —C n —F 2n+1−h H h groups, with m, n being integers from 1 to 3, h being integer ≧1, chosen so that h≦2n+1, with the proviso that at least one of R* and R*′ is a —C n —F 2n+1−h H h group, as defined above;
R f ′ is chosen from structures (1), (2), or (3) where:
structure (1) is —(CF 2 O) a —(CF 2 CF 2 O) b —(CF 2 —(CF 2 ) z′ —CF 2 O) c , with a, b and c being integers up to 50, and z′ being an integer equal to 1 or 2, a≧0, b≧0, c≧0 and a+b>0;
structure (2) is —(C 3 F 6 O) c′ —(C 2 F 4 O) b —(CFXO) t —, with X being, at each occurrence, independently —F or —CF 3 ; b, c′ and t being integers up to 10, c′>0, b≧0, t≧0; and
structure (3) is —(C 3 F 6 O) c′ —(CFXO) t —, with X being, at each occurrence, independently —F or —CF 3 ; c′ and t being integers up to 10, c′>0, t≧0.

5. The liquid composition of claim 4 where R f ′ is selected from structures (1) or (2).

6. The liquid composition of claim 1 , wherein the fluorocarbon liquid medium comprises the methoxy nonafluorobutane isomers (CF 3 ) 2 CFCF 2 —O—CH 3 and/or CF 3 CF 2 CF 2 CF 2 —O—CH 3 .

7. The liquid composition of claim 1 , wherein the monomeric units deriving from a bis-olefin have the formula:
R 1 R 2 C═CH—(CF 2 ) m —CH═CR 5 R 6

wherein: m=2-10, R 1 , R 2 , R 5 , R 6 , are equal to or different from each other and are H or C 1 -C 5 alkyl groups.

8. The liquid composition of claim 7 , wherein the fluorinated monomeric units containing ethylenic groups and functional groups have the formula:
CF 2 ═CF—O—CF 2 CF 2 SO 2 F.

9. The liquid composition of claim 1 , wherein the liquid composition additionally comprises a crosslinking agent and a radical initiator.

10. The liquid composition of claim 9 , wherein the bis-olefin has the formula:
R 1 R 2 C═CH—(CF 2 ) m —CH═CR 5 R 6

wherein: m=2-10, R 1 , R 2 , R 5 , R 6 , are equal to or different from each other and are H or C 1 -C 5 alkyl groups.

11. The liquid composition of claim 9 , wherein the radical initiator is an organic dialkyl peroxide.

12. The liquid composition of claim 9 wherein the radical initiator is 2,5-di(t-butylperoxy)-2,5-dimethylhexane.

13. The liquid composition of claim 1 , wherein at least 95% by weight of the fluorinated ionomer consists in particles of size lower than 200 nm.

14. The liquid composition of claim 1 , wherein at least 99% by weight of the fluorinated ionomer consists in particles of size lower than 200 nm.

15. The liquid composition of claim 14 , wherein at least 99% by weight of the fluorinated ionomer consists in particles of size lower than 125 nm.

16. The liquid composition of claim 14 , wherein at least 99% by weight of the fluorinated ionomer consists in particles of size lower than 40 nm.

17. The liquid composition of claim 14 , wherein at least 99% by weight of the fluorinated ionomer consists in particles of size lower than 15 nm.

Assignees

• Gjoka Alketa
• Raman Ven Anantha
• Gebert Matthias
• Oldani Claudio
• Ghielmi Alessandro
• Entegris Inc
• Solvay Specialty Polymers It

Inventors

• Gjoka Alketa
• Raman Ven Anantha
• Gebert Matthias
• Oldani Claudio
• Ghielmi Alessandro

Classifications

• B01D65/10

  Testing of membranes or membrane apparatus; Detecting or repairing leaks · CPC title

• B01D2323/02

  Hydrophilization · CPC title

• B01D71/32

  containing fluorine atoms · CPC title

• B01D2323/30

  Cross-linking · CPC title

• B01D67/0088

  Physical treatment with compounds, e.g. swelling, coating or impregnation · CPC title