Ion exchange membrane

Patent metadata

Field	Value
Publication number	US-10252257-B2
Application number	US-201615574976-A
Country	US
Kind code	B2
Filing date	May 16, 2016
Priority date	May 18, 2015
Publication date	Apr 9, 2019
Grant date	Apr 9, 2019

Abstract

The ion exchange membrane according to the present invention comprises a layer A comprising a fluorine-containing polymer having a sulfonic acid group and a layer B comprising a fluorine-containing polymer having a carboxylic acid group, wherein a ratio of an ion cluster diameter of the layer B after electrolysis under the following electrolysis conditions to the ion cluster diameter of the layer B before the electrolysis [(the ion cluster diameter of the layer B after the electrolysis)/(the ion cluster diameter of the layer B before the electrolysis)] is 0.83 to 0.95:
(Electrolysis Conditions)
in a zero-gap base electrolytic cell where the ion exchange membrane is disposed between an anode chamber to which a 3.5 N aqueous sodium chloride solution is supplied and a cathode chamber to which a 10.8 N aqueous sodium hydroxide solution is supplied, electrolysis is performed for 7 days under conditions having a temperature of 85° C. and a current density of 6 kA/m 2 .

First claim

The invention claimed is:

1. An ion exchange membrane comprising:
a layer A comprising a fluorine-containing polymer having a sulfonic acid group; and
a layer B comprising a fluorine-containing polymer having a carboxylic acid group, wherein
a ratio of an ion cluster diameter of the layer B after electrolysis under the following electrolysis conditions to the ion cluster diameter of the layer B before the electrolysis [(the ion cluster diameter of the layer B after the electrolysis)/(the ion cluster diameter of the layer B before the electrolysis)] is 0.83 to 0.95:

(Electrolysis conditions)
in a zero-gap base electrolytic cell where the ion exchange membrane is disposed between an anode chamber to which a 3.5 N aqueous sodium chloride solution is supplied and a cathode chamber to which a 10.8 N aqueous sodium hydroxide solution is supplied, electrolysis is performed for 7 days under conditions having a temperature of 85° C. and a current density of 6 kA/m 2 .

2. The ion exchange membrane according to claim 1 , wherein
the ion cluster diameter of the layer B before the electrolysis is 2.5 to 4.0 nm; and
the ion cluster diameter of the layer B after the electrolysis is 2.0 to 3.3 nm.

3. The ion exchange membrane according to claim 1 , wherein a sum of a thickness of the layer A and a thickness of the layer B before the electrolysis is 55 μm or more.

4. The ion exchange membrane according to claim 1 , wherein the ion cluster diameter of the layer A before the electrolysis is 3.0 to 4.5 nm.

5. The ion exchange membrane according to claim 1 , wherein
a thickness of the layer A before the electrolysis is 50 to 180 μm; and
a thickness of the layer B before the electrolysis is 5 to 20 μm.

6. The ion exchange membrane according to claim 1 , wherein
the layer A comprises a polymer of a compound represented by the following formula (2); and
the layer B comprises a polymer of a compound represented by the following formula (3):
CF 2 ═CF—(OCF 2 CYF) a —O—(CF 2 ) b —SO 2 F  (2)

wherein a represents an integer of 0 to 2, b represents an integer of 1 to 4, and Y represents —F or —CF 3 ; and
CF 2 ═CF—(OCF 2 CYF) c —O—(CF 2 ) d —COOR  (3)

wherein c represents an integer of 0 to 2, d represents an integer of 1 to 4, Y represents —F or —CF 3 , and R represents —CH 3 , —C 2 H 5 , or —C 3 H 7 .

7. An electrolytic cell comprising the ion exchange membrane according to claim 1 .

Assignees

• Asahi Chemical Ind

Inventors

• Nakajima Atsushi
• Sakamoto Naoki
• Morikawa Takuya

Classifications

• C25B13/08 Primary

  based on organic materials · CPC title

• C08J5/2237

  containing fluorine · CPC title

• C25B9/00

  Cells or assemblies of cells; Constructional parts of cells; Assemblies of constructional parts, e.g. electrode-diaphragm assemblies; Process-related cell features · CPC title

• B01J39/20

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

• B32B27/322

  comprising halogenated polyolefins, e.g. PTFE · CPC title