PURPOSE: To obtain a dehumidifying method wherein permeation velocity of steam and permselective constant thereof are large by drying and treating a membrane made of a fluorine-contg. ion exchangeable polymer having the specified ion exchange capacity at the temp. not higher than the glass transition temp. of this polymer.
CONSTITUTION: A fluorine-contg. copolymer which is made of resin having 0.6 to 2.5 milliequivalent/g-resin ion exchange capacity and especially incorporates the component shown in a general formula I ((m) shows 0 or 1, (n) shows integer of 2 to 5) is utilized as a fluorine-contg. ion exchange layer. Furthermore, the characteristics of a membrane are regulated to 1 to 6meq/g H2O concn. γ of fixed ion, 20 to 250wt.% coefficient of water absorption and 0.1 to 100μm film thickness. Then the membrane is dried and treated at the temp. not higher than glass transition temp. especially at the temp. not higher than at least 25°C for the glass transition temp. This membrane removes water not less than at least 30% of coefficient of water absorption of the ion exchange layer. Thereby, the membrane large in permeation velocity of steam and permselective constant thereof is obtained and dehumidification is performed by utilizing this membrane.
WAKABAYASHI HIROKAZU
SUGAYA YOSHIO
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