Asahi Kasei Kogyo Kabushiki Kaisha

Hisashi Wakamatsu

Yasuhide Noaki

Hiroshi Sagami

A cation exchange membrane having having durability, which is adapted for use in electrolysis or an alkali metal chloride, which comprises a quadrilateral base membrane and, disposed on at least one marginal area of one surface of the base membrane, a diffusion coating having a capability for an alkali metal hydroxide to diffuse therethrough at a diffusion velocity greater than that at which the alkali metal hydroxide diffuses through a fluorocarbon polymer layer constituting the base membrane when the base membrane is composed of one fluorocarbon polymer layer or through one outermost layer of the base membrane which layer has thereon the diffusion coating and has a water sorption smaller than that of the opposite outermost layer of the base membrane, when the base membrane is composed of a plurality of fluorocarbon polymer layers. The cation exchange membrane is free, for a prolonged period of time, from the local lowering of the mechanical strength of the membrane as caused by the precipitation of an alkali metal chloride within and the formation of oxygen in nascent state within the base membrane during the electrolysis of an alkali metal chloride.

Cation exchange membrane having high durability with diffusion coating

A hydrogen-evolution electrode comprising an electrically conductive substrate having thereon a coating comprising a chromium component, a titanium component and an oxide of at least one metal selected from the group consisting of nickel and cobalt, said chromium component and titanium component being present in proportions, in terms of atomic percentage, of 0.5 to 40% and 0.1 to 10%, respectively. The titanium component retards the dissolution rate of the chromium component. Accordingly, the electrode has a life several times as long as that of the conventional electrodes, and can exhibit an advantageously low hydrogen overvoltage for a prolonged period of time. Also, the electrode can be advantageously employed to produce an alkali product improved in purity. Such a hydrogen-evolution electrode can be produced by melt-spraying onto a substrate a mixture of a finely divided powder of at least one member selected from the first group consisting of nickel, nickel compounds, cobalt and cobalt compounds, a finely divided powder of at least one member selected from the second group consisting of chromium and chromium compounds and a finely divided powder of at least one member selected from the third group consisting of titanium and titanium compounds. In the production, when the above-mentioned mixture is subjected to granulation and the obtained granules are melt-sprayed, there can be obtained the desired electrode having excellent properties with respect to catalytic activity and durability in high spraying yield.

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Kanagawa, Japan

Hisashi Wakamatsu