Ion exchange film operated under ultrahigh current density condition and preparation method of ion exchange film

Abstract

The invention relates to an ion exchange film operated under an ultrahigh current density condition and a preparation method of the ion exchange film. The film is a three-structure composite film which consists of a perfluorinated sulfonic acid resin film with high exchange capacity, a perfluorinated hot melting adhesive high-elastic film with the low molecular amount and the thickness of 1-30 microns and a perfluorinated carboxylic acid resin film with low exchange capacity. By the composite film, an enhanced ion exchange film is formed by using a fiber mesh or a microporous film. The invention also provides a method for preparing the ion exchange film, solves the problem of stripping and deformation caused by large ion flux difference between the sulfoacid film with the high exchange capacity and the carboxylic acid film with the low exchange capacity under a high current density condition, and has high electrolysis performance under a condition that the operation speed is up to 6-20KA / m<2>.

Description

technical field [0001] The invention relates to an ion exchange membrane operating under the condition of ultra-high current density, which belongs to the field of functional polymer composite materials. Background technique [0002] In the chlor-alkali industry, according to the operating current density, ion-exchange membrane electrolyzers can be divided into high current density electrolyzers and general current density electrolyzers. The critical point of the two is usually set at 4.0KA / m 2 . The current density of the traditional ion-exchange membrane electrolyzer is 3.3KA / m 2 The current density of the high current density ion membrane electrolyzer is generally 4.0-6.0KA / m 2 or higher. [0003] Relatively speaking, the operation of high current density electrolyzer has the following advantages: 1) It can strengthen the production capacity, such as 4.2KA / m 2 The electrolyzer operating under the condition is more than 3.3KA / m 2 The electrolyzer operating under the ...

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Problems solved by technology

[0004] Patent ZL200720010486.2 discloses a high current density expanded anode electrolytic cell used in the chlor-alkali industry, which realizes safe and stable operation of electrolysis at high current density from the improvement of the electrolytic cell structure; The current density ion exchange membrane adopts thinner membrane thickness and finer reinforcing fibers to reduce the blocking area and increase the flux. The effect is more obvious, but the strength of the membrane is much lower and the life is shortened; the patent US2005 / 0279644A1 discloses a The ionic membrane electrolysis process can make the ionic membrane adapt to the stable operation under different current density conditions, but it is only realized by adjusting the distance between the ionic membrane and the anode, and the current density can only be increased to 7KA / m 2

Generally speaking, in order to improve the ion flux of the ion exchange membrane, the simplest method is to use a high exchange capacity sulfonic acid or carboxylic acid resin to prepare a high exchange capacity ion membrane, but in the actual preparation and application process, carboxyl If the exchange capacity of the acid is too high, the barrier performance of the cathode side to hydroxide is reduced, resulting in an excess of hydrogen in the chlorine gas; while increasing the exchange capacity of sulfonic acid alone has the defect that it does not match with the carboxylic acid resin and is easy to delaminate

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