| 摘要 |
PURPOSE:To combine the membrane with the board firmly, by applying membrane making liquid on high pressure side while giving pressure differnce as it is on both sides of porous board impregnated impregnating liquid and forming thin membrane. CONSTITUTION:Water, ethylene glycol, glycerol or the mixture of the above material (impregnating liquid), are impregnated in porous board. Pressure having smaller than bubble point (pressure shown the bubble at first by pushing fully contained impregnating liquid out of the opposite side) and larger than one-fourth of the bubble point, is given. Solution (membrane making agent) dissolved high molecular compound to be made thin membrane in solvent, such as benzene, toluene etc., not mixing with the impregnating liquid substantially, by applying the above pressure. Thus, surplus impregnating liquid remained on the membrane forming surface, is pushed in the porous board and contact surface with membrance board is made sufficiently. Keeping of the above pressure difference is continued until to form the thin film by evaporating the solvent in the membrane making agent. |
