Method for preparing perfluorocarboxylic acid ion membranes by liquid surface tape casting method

Abstract

The invention relates to a method for preparing perfluorocarboxylic acid ion membranes, which is characterized in that the method comprises the following steps: (1) dissolving perfluorocarboxylic acid resin into a solvent for forming a uniform perfluorocarboxylic acid resin solution A; (2) adding materials with low melting point and high density into a heatable container, heating the container for dissolving the materials, and forming uniform liquid B in the container; (3) preheating the perfluorocarboxylic acid resin solution A and pouring the perfluorocarboxylic acid resin solution A onto the surface of the liquid B protected by nitrogen gas so that a thin layer solution is formed on the surface of the liquid B through casting; (4) heating the liquid B, then carrying out program temperature reduction, and continuously introducing the nitrogen gas for protection in the whole process; and (5) evaporating most or all of the solvent in the perfluorocarboxylic acid resin solution A to obtain the perfluorocarboxylic acid ion membrane on the surface of the liquid B. The perfluorocarboxylic acid ion membrane prepared by the invention can be applied to composite layers of sodium hudroxide use ion membranes, and has the advantages of uniform thickness, difficult bubble generation and stable performance, and the invention provides reliable carboxylic acid layer ion membranes for producing the sodium hudroxide use ion membranes.

Description

technical field [0001] The invention relates to a method for preparing a perfluorocarboxylic acid ion membrane, in particular to a method for preparing a perfluorocarboxylic acid ion membrane by a liquid surface casting method. Background technique [0002] The technology of preparing chlor-alkali by perfluorinated ion membrane is a revolution in the chlor-alkali industry. It is a chlor-alkali production technology with low energy consumption, no pollution, and high product quality. my country has introduced nearly 10 million tons from the United States and Japan in more than ten years. The complete set of ion membrane equipment has greatly improved the equipment level of my country's chlor-alkali industry and solved the problem that my country's high-quality caustic soda needs to be imported. With the progress of society and the development of science and technology, caustic soda by mercury method and part of caustic soda by graphite anode diaphragm method will be completely...

AI Technical Summary

Problems solved by technology

This method has too many procedures and cumbersome operation, which is not conducive to mass production

There are also researchers who mix perfluorocarboxylic acid ion exchange resins with -COOH and -COONa structures and solvents to prepare a solution, and then cast the solution on the surface of the solid phase to form a film. During the film formation process of this casting method, The concentration of the casting solution is high and must have a certain viscosity. The parameters of the solution have a great influence on the result of casting film formation. Moreover, the material, flatness, and thermal expansion coefficient of the casting substrate will affect the thickness of the film. Uniform and stable performance

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