Production method for ion exchange membrane for alkali chloride electrolysis, and production method for alkali chloride electrolysis apparatus

Patent metadata

Field	Value
Publication number	US-10703872-B2
Application number	US-201815909013-A
Country	US
Kind code	B2
Filing date	Mar 1, 2018
Priority date	Sep 8, 2015
Publication date	Jul 7, 2020
Grant date	Jul 7, 2020

Abstract

To provide a method whereby it is possible to efficiently produce an ion exchange membrane for alkali chloride electrolysis, which has high current efficiency and high alkali resistance at the time of electrolyzing an alkali chloride. This is a method for producing an ion exchange membrane 1 for alkali chloride electrolysis, having a layer (C) 12 containing a fluorinated polymer (A) having carboxylic acid type functional groups, by immersing an ion exchange membrane precursor film having a precursor layer (C′) containing a fluorinated polymer (A′) having groups convertible to carboxylic acid type functional groups, in an aqueous alkaline solution comprising an alkali metal hydroxide, a water-soluble organic solvent and water, and subjecting the groups convertible to carboxylic acid type functional groups to hydrolysis treatment to convert them to carboxylic acid type functional groups, wherein the concentration of the water-soluble organic solvent is from 1 to 60 mass % in the alkaline aqueous solution (100 mass %); the proportion of structural units having carboxylic acid type functional groups in the fluorinated polymer (A) is from 14.00 to 14.50 mol %; and the resistivity in the layer (C) 12 is from 3.0×10 3 to 25.0×10 3 Ω·cm.

First claim

What is claimed is:

1. A production method for an ion exchange membrane for alkali chloride electrolysis, which is a method for producing an ion exchange membrane for alkali chloride electrolysis having a layer containing a fluorinated polymer having carboxylic acid or carboxylate functional groups, by immersing an ion exchange membrane precursor film having a precursor layer containing a fluorinated polymer having groups convertible to carboxylic acid or carboxylate functional groups, in an alkaline aqueous solution containing an alkali metal hydroxide, a water-soluble organic solvent and water, and subjecting the groups convertible to carboxylic acid or carboxylate functional groups to hydrolysis treatment to convert them to carboxylic acid or carboxylate functional groups, wherein
the concentration of the water-soluble organic solvent is from 1 to 60 mass % in the alkaline aqueous solution (100 mass %),
a proportion of structural units having the carboxylic acid or carboxylate functional groups in the fluorinated polymer having the carboxylic acid or carboxylate functional groups, is from 14.00 to 14.50 mol %, in all structural units (100 mol %) in the fluorinated polymer having the carboxylic acid or carboxylate functional groups, and
the resistivity in the layer containing the fluorinated polymer having the carboxylic acid or carboxylate functional groups is from 3.0×10 3 to 25.0×10 3 Ω·cm.

2. The production method for an ion exchange membrane for alkali chloride electrolysis according to claim 1 , wherein the water content of the layer containing the fluorinated polymer having the carboxylic acid or carboxylate functional groups is from 3.5 to 11.5 mass %.

3. The production method for an ion exchange membrane for alkali chloride electrolysis according to claim 1 , wherein the concentration of the alkali metal hydroxide is from 1 to 60 mass % in the alkaline aqueous solution (100 mass %).

4. The production method for an ion exchange membrane for alkali chloride electrolysis according to claim 3 , wherein the concentration of the alkali metal hydroxide is from 5 to 50 mass % in the alkaline aqueous solution (100 mass %).

5. The production method for an ion exchange membrane for alkali chloride electrolysis according to claim 1 , wherein the concentration of the water-soluble organic solvent is from 5 to 50 mass % in the alkaline aqueous solution (100 mass %).

6. The production method for an ion exchange membrane for alkali chloride electrolysis according to claim 5 , wherein the concentration of the alkali metal hydroxide is from 5 to 50 mass % in the alkaline aqueous solution (100 mass %).

7. The production method for an ion exchange membrane for alkali chloride electrolysis according to claim 1 , wherein the alkali metal hydroxide is sodium hydroxide or potassium hydroxide.

8. The production method for an ion exchange membrane for alkali chloride electrolysis according to claim 1 , wherein the water-soluble organic solvent is at least one member selected from the group consisting of aprotic water-soluble organic solvents, alcohols and aminoalcohols.

9. The production method for an ion exchange membrane for alkali chloride electrolysis according to claim 8 , wherein the water-soluble organic solvent is at least one member selected from the group consisting of dimethyl sulfoxide, methyl alcohol, ethyl alcohol, propyl alcohol, 1-methoxy-2-propanol, triethanolamine, diethanolamine, isopropanolamine, triisopropanolamine, dimethylaminoethanol and diethylaminoethanol.

10. The production method for an ion exchange membrane for alkali chloride electrolysis according to claim 1 , which is a method for producing an ion exchange membrane for alkali chloride electrolysis further having a layer containing a fluorinated polymer having sulfonic acid or sulfonate functional groups, wherein
the ion exchange membrane precursor film further has a precursor layver containing a fluorinated polymer having groups convertible to sulfonic acid or sulfonate functional groups,
the ion exchange membrane precursor film is immersed in the alkaline aqueous solution, and the groups convertible to carboxylic acid or carboxylate functional groups are subjected to hydrolysis treatment and converted to carboxylic acid or carboxylate functional groups, and at the same time, the groups convertible to sulfonic acid or sulfonate functional groups are subjected to hydrolysis treatment and converted to sulfonic acid or sulfonate functional groups.

11. The production method for an ion exchange membrane for alkali chloride electrolysis according to claim 1 , wherein the ion exchange membrane for alkali chloride electrolysis further has a layer comprising inorganic particles and a binder, and wherein the layer comprising the inorganic particles and the binder is an outermost layer.

12. The production method for an ion exchange membrane for alkali chloride electrolysis according to claim 1 , wherein the current efficiency of the ion exchange membrane, measured by the following method for measuring current efficiency, is at least 95.8%:
Method for measuring current efficiency: The ion exchange membrane is mounted to partition the inside of an electrolytic cell into a cathode chamber on the cathode side and an anode chamber on the anode side; the cathode side is brought in a pressurized state so as to contact the anode and the ion exchange membrane; and electrolysis is conducted for one week under conditions of a temperature of 90° C. and a current density of 6 kA/m 2 , while supplying a 290 g/L sodium chloride aqueous solution and water, respectively, to the anode chamber and the cathode chamber, and maintaining the concentration of sodium chloride discharged from the anode chamber to be 200 g/L, and the concentration of sodium hydroxide discharged from the cathode chamber to be 32 mass %, and the current efficiency after the one week is measured.

13. The production method for an ion exchange membrane for alkali chloride electrolysis according to claim 1 , wherein the temperature of the alkaline aqueous solution is from 40 to 95° C., at the time of immersing the ion exchange membrane precursor film having a precursor layer containing a fluorinated polymer having groups convertible to carboxylic acid functional groups, in the alkaline aqueous solution containing an alkali metal hydroxide, water-soluble organic solvent and water, to subject the groups convertible to the carboxylic acid functional groups to hydrolysis treatment to convert them to the carboxylic acid or carboxylate functional groups.

14. A production method for an alkali chloride electrolysis apparatus, which comprises mounting an ion exchange membrane for alkali chloride electrolysis obtained by the production method for an ion exchange membrane for alkali chloride electrolysis as defined in claim 1 , in an electrolytic cell comprising a cathode and an anode, so as to partition the inside of the electrolytic cell into a cathode chamber on the cathode side and an anode chamber on the anode side.

15. A production method for an ion exchange membrane for alkali chloride electrolysis, which is a method for producing an ion exchange membrane for alkali chloride electrolysis having a layer containing a fluorinated polymer having carboxylic acid or carboxy late functional groups, by immersing an ion exchange membrane precursor film having a precursor layer containing a fluorinated polymer having groups convertible to carboxylic acid or carboxylate functional groups, in an alkaline aqueous solution containing an alkali metal hydroxide, a water-soluble organic solvent and water, and subjecting the groups convertible t

Assignees

• Agc Inc

Inventors

• Chinsoga Tamaki
• Nishio Takuo
• Yamaki Yasushi
• Kaneko Takayuki

Classifications

• C25B13/08 Primary

  based on organic materials · CPC title

• C25B9/19

  with diaphragms · CPC title

• C08J5/22

  Films, membranes or diaphragms · CPC title

• C25B1/46

  in diaphragm cells · CPC title

• C25B1/34

  Simultaneous production of alkali metal hydroxides and chlorine, oxyacids or salts of chlorine, e.g. by chlor-alkali electrolysis · CPC title