Abstract: A recording medium has an ink-receiving layer provided on at least one surface of a substrate, wherein the substrate comprises a base material, and a resin layer having ink absorbency and/or ink permeability formed at least on the side of the base material on which the ink-receiving layer is provided, and wherein the resin layer has a contact angle with respect to water of 60° or smaller, a water vapor transmission rate of 100 g/m2/24 hr or larger according to JIS-Z-0208 and the thickness of 10 to 100 ?m.

Abstract: A method for the electrolysis of an alkali metal chloride in an electrolytic cell is disclosed, in which use is made of a cation exchange membrane comprising a carboxylate-containing fluorocarbon polymer layer disposed on a cathode compartment side and provided on its surface with an inorganic coating, and a sulfonate and/or carboxylate-containing fluorocarbon polymer layer disposed on an anode compartment side and having a water content of from 3 to 10% by weight. By this method, an alkali metal hydroxide, e.g., sodium hydroxide, can be directly produced in a concentration as high as 45-55 % by weight from a saline solution having an alkali metal chloride concentration as low as from 3.0 to 3.5N with reduced energy consumption, stably for a prolonged period of time.

Abstract: A highly stable cation exhange membrane for use in the electrolysis of an alkali metal chloride is disclosed, which comprises a reinforced base membrane comprised of at least one layer of a fluorocarbon polymer and a reinforcing woven fabric encapsulated therein and a coating disposed on at least one surface of the reinforced base membrane, the coating comprising particles of at least one inorganic material selected from the group consisting of oxides, nitrides and carbides of elements belonging to group IV of the periodic table, which particles have an average primary particle diameter as small as from 0.01 to 0.2 .mu.m, and a binder polymer. In the cation exchange membrane, the coating containing particles of an inorganic material, uniformly and strongly adheres to the surface of the reinforced base membrane, so that the inorganic material can remain in the coating for a prolonged period of time.

Abstract: A novel process is disclosed in which a membrane of a fluorinated resin containing a pendant precursor ion exchange group represented by the formula:--SO.sub.2 Xwherein X rerpesents a halogen atom, is contacted with a aqueous solution containing specific amounts of at least one alkali metal or alkaline earth metal hydroxide and at least one specific water soluble organic compound to thereby hydrolyze the precursor group while causing a specific membrane volume increase. In the process of the present invention , since the ion exchange membrane is swelled, while being hydrolyzed, to a desired degree, the rate of hydrolysis of precursor ion exchange groups is high, so that a final ion exchange membrane is free of wrinkles formed during the hydrolysis step of a conventional process and during the electrolytic operation, thereby enabling the final membrane to ensure advantageously low cell voltage and stable, prolonged electrolytic operation.

Abstract: A novel process is provided in which a membrane of a fluorinated resin having pendant ion exchange precursor groups represented by at least one formula selected from the group consisting of:--SO.sub.2 X and --CYwherein X represents a halogen atom or --OR in which R represents an alkyl group having 1 to 4 carbon atoms, and Y represents a nitrogen atom or --OX in which X is as defined above, is contacted with an aqueous solution of a basic organic compound for a period of time sufficient to perform the hydrolysis of the precursor groups. In the process of the present invention, a complicated pre-swelling step as conventionally conducted in the art is advantageously omitted. Nevertheless, an ion exchange membrane having excellent dimensional stability and performance stability can be obtained. In addition, when the obtained membrane is used in an electrolytic cell, the cell exhibits an extremely low cell voltage.