Process for producing ion exchange membrane for electrolysis, and ion exchange membrane for electrolysis

Patent metadata

Field	Value
Publication number	US-2018043344-A1
Application number	US-201715728694-A
Country	US
Kind code	A1
Filing date	Oct 10, 2017
Priority date	Apr 13, 2015
Publication date	Feb 15, 2018
Grant date	—

Abstract

To provide a process for producing an ion exchange membrane for electrolysis which has a low membrane resistance and which is capable of reducing the electrolysis voltage during the electrolysis, even if the membrane strength is increased, an ion exchange membrane for electrolysis, a precursor membrane of an ion exchange membrane for electrolysis, and an electrolysis apparatus.
In a fluorinated polymer having groups convertible to ion exchange groups, a reinforcing fabric 20 A formed by weaving covered yarns 21 each comprising a reinforcing fabric 22 and a sacrificial material covering at least a portion of the outer peripheral surface of the reinforcing yarn 22 , to produce a precursor membrane of an ion exchange membrane, and from the precursor membrane, at least a portion of the sacrificial material in the reinforcing fabric is eluted to form a reinforcing material and at the same time, the groups convertible to ion exchange groups are converted to ion exchange groups, to produce an ion exchange membrane for electrolysis.

First claim

What is claimed is:

1 . A process for producing an ion exchange membrane for electrolysis, which comprises a step (a) of embedding, in a fluorinated polymer having groups convertible to ion exchange groups, a reinforcing fabric formed by weaving covered yarns each comprising a reinforcing yarn and a sacrificial material covering at least a portion of the outer peripheral surface of the reinforcing yarn, to produce a precursor membrane of an ion exchange membrane for electrolysis, and a step (b) of eluting, from the precursor membrane of an ion exchange membrane for electrolysis, at least a portion of the sacrificial material in the reinforcing fabric to form a reinforcing material and at the same time, converting the groups convertible to ion exchange groups to ion exchange groups.

2 . The process for producing an ion exchange membrane for electrolysis according to claim 1 , wherein the covered yarns are covered twisted yarns each having the reinforcing yarn as a core yarn and a wrap yarn composed of a sacrificial material wound on at least a portion of the outer peripheral surface of the core yarn.

3 . The process for producing an ion exchange membrane for electrolysis according to claim 1 , wherein between the outer peripheral surface of at least a portion of the reinforcing yarns and the fluorinated polymer, a region (p) which is either a region (p 1 ) formed by a void or a region (p 2 ) formed by a void and the sacrificial material, is continuously formed from a first edge side toward a second edge side in a longitudinal direction of the reinforcing yarn.

4 . The process for producing an ion exchange membrane for electrolysis according to claim 3 , wherein the region (p) is formed in a tubular form along the longitudinal direction of the reinforcing yarn on the outer peripheral surface of the reinforcing yarn or is formed in a spiral form so as to be wound on the outer peripheral surface of the reinforcing yarn.

5 . The process for producing an ion exchange membrane for electrolysis according to claim 3 , wherein in a cross section at right angles to the lengthwise direction of at least a portion of the reinforcing yarns, the following angle (x) of a portion facing the above region (p) based on the outer periphery of the reinforcing yarn, is from 60 to 360°:
angle (x): an angle formed by two lines drawn from a centroid Pc of the reinforcing yarn in the cross section so as to sandwich a portion (T) facing the region (p) formed on the outer peripheral surface of the reinforcing yarn; in a case where there are two or more portions (T), the angle (x) is the sum of the angles corresponding to the respective portions (T); and in a case where the portion (T) is present on the entire outer periphery of the reinforcing yarn, the angle (x) is 360°.

6 . The process for producing an ion exchange membrane for electrolysis according to claim 3 , wherein in a cross section at right angles to the lengthwise direction of at least a portion of the reinforcing yarns, the ratio of a cross sectional area (y 2 ) of the region (p) formed on the outer periphery of the reinforcing yarn to the sum of a cross sectional area (y 1 ) of the reinforcing yarn and the cross sectional area (y 2 ) of the region (p), i.e. [y 2 /(y 1 +y 2 )] is from 5 to 50%.

7 . The process for producing an ion exchange membrane for electrolysis according to claim 1 , wherein the thickness of the reinforcing fabric is from 10 to 300 μm.

8 . The process for producing an ion exchange membrane for electrolysis according to claim 1 , wherein the reinforcing fabric is a reinforcing fabric formed by weaving the covered yarns and sacrificial yarns composed of the sacrificial material, and at least a portion of the sacrificial yarns is eluted in the step (b).

9 . The process for producing an ion exchange membrane for electrolysis according to claim 1 , wherein the ion exchange membrane is used to electrolyze an aqueous alkali chloride solution.

10 . An ion exchange membrane for electrolysis, which comprises a fluorinated polymer having ion exchange groups and a reinforcing material embedded in the fluorinated polymer, wherein between the fluorinated polymer and an outer peripheral surface of at least a portion of reinforcing yarns among reinforcing yarns constituting the reinforcing material, a region (p) which is either a region (p 1 ) formed by a void or a region (p 2 ) formed by a void and a sacrificial material is continuously formed from a first edge side toward a second edge side in the longitudinal direction of the reinforcing yarns.

11 . The ion exchange membrane for electrolysis according to claim 10 , wherein the region (p) is formed in a tubular form along the longitudinal direction of the reinforcing yarn on the outer peripheral surface of the reinforcing yarn or is formed in a spiral form so as to be wound on the outer peripheral surface of the reinforcing yarn.

12 . The ion exchange membrane for electrolysis according to claim 10 , wherein in a cross section at right angles to the lengthwise direction of at least a portion of the reinforcing yarns, the following angle (x) of a portion facing the above region (p) based on the outer periphery of the reinforcing yarn, is from 60 to 360°:
angle (x): an angle formed by two lines drawn from a centroid Pc of the reinforcing yarn in the cross section so as to sandwich a portion (T) facing the region (p) formed on the outer peripheral surface of the reinforcing yarn; in a case where there are two or more portions (T), the angle (x) is the sum of the angles corresponding to the respective portions (T); and in a case where the portion (T) is present on the entire outer periphery of the reinforcing yarn, the angle (x) is 360°.

13 . The ion exchange membrane for electrolysis according to claim 10 , which has a thickness of from 150 to 350 μm.

14 . The ion exchange membrane for electrolysis according to claim 10 , wherein in a cross section at right angles to the lengthwise direction of at least a portion of the reinforcing yarns, the ratio of a cross sectional area (y 2 ) of the region (p) formed on the outer periphery of the reinforcing yarn to the sum of a cross sectional area (y 1 ) of the reinforcing yarn and the cross sectional area (y 2 ) of the region (p), i.e. [y 2 /(y 1 +y 2 )] is from 5 to 50%.

15 . The ion exchange membrane for electrolysis according to claim 10 , which is used to electrolyze an aqueous alkali chloride solution.

16 . A precursor membrane of an ion exchange membrane for electrolysis, which comprises a fluorinated polymer having groups convertible to ion exchange groups and a reinforcing fabric embedded in the fluorinated polymer, wherein the reinforcing fabric is a reinforcing fabric formed by weaving covered yarns each comprising a reinforcing yarn and a sacrificial material covering at least a portion of the outer peripheral surface of the reinforcing yarn.

17 . The precursor membrane of an ion exchange membrane for electrolysis according to claim 16 , which is used to electrolyze an aqueous alkali chloride solution.

18 . An electrolysis apparatus comprising an electrolytic cell provided with a cathode and an anode, and the ion exchange membrane for electrolysis as defined in claim 10 disposed in the electrolytic cell so as to partition inside of the electrolytic cell into a cathode chamber on the cathode side and an anode chamber on the anode side.

19 . The electrolysis apparatus according to claim 18 , which is used to electrolyze an aqueous alkali chloride solution.

Assignees

• Asahi Glass Co Ltd

Inventors

• Kaneko Takayuki
• Kusano Hiromitsu
• Yamaki Yasushi
• Nishio Takuo

Classifications

• C25B13/08 Primary

  based on organic materials · CPC title

• C25B9/08

  Chemistry & Metallurgy · mapped topic

• B01J39/05 Primary

  in the strongly acidic form · CPC title

• C08J5/2281

  fluorine containing heterogeneous membranes · CPC title

• B01J47/12

  characterised by the use of ion-exchange material in the form of ribbons, filaments, fibres or sheets, e.g. membranes (electrodialysis or electro-osmosis B01D61/42) · CPC title