PURPOSE: To obtain a gas separating composite membrane good in oxygen separation capacity and capable of lasting said capacity for a long period of time, by laminating two layers of membranes each having gas separation capacity on a porous membrane having no gas separation capacity.
CONSTITUTION: As an porous membrane having no gas separation capacity, one with an average pore size of 0.001W0.5μm and a porosity of 10W70% is used and the thickness thereof is pref. about 20W300μm. It is necessary that the gas separation capacity of first membrane is Po/Pn2=2W2.5 and the coefficient of gas permeation thereof is Po2=10-8W10-7cc.cm/cm2.sec.cmHg and the thickness thereof is pref. about 0.3W3μm. In addition, the material thereof is pref. polyorganosiloxane. Further, it is necessary that the gas separation capacity of a second membrane is Po2/PN2=3W6 and the coefficient of gas permeation thereof is Po2=10-10W10-8cc.cm/cm2.sec.cmHg and the material theeof comprises polyvinyl pivalate. By laminating three kinds of these membranes, an objective gas separation membrane is obtained.
KOBAYASHI SHIGEYOSHI
YOSHIHARA NORIYUKI
NAKAMURA HIDE
| JPS5730528A | 1982-02-18 | |||
| JPS57105203A | 1982-06-30 | |||
| JPS54146277A | 1979-11-15 |