| 摘要 |
PURPOSE:To obtain an ultrafiltration membrane excellent in solvent resistance, by treating a fluorine contained high-molecular membrane with fluorine gas. CONSTITUTION:A porous membrane comprising a fluorine contained high-molecular polymer, for example, polyvinylidene fluoride is molded and treated, pref., at about 20-100 deg.C in a reactor filled with fluorine gas, pref., fluorine gas diluted about 100 times with inert gas. After treatment, the internal gas is exhausted and the treated porous membrane is taken out to be directly immersed in an aqueous solution containing alkali metal carbonate, for example, sodium carbonate in order to remove the fluorine gas adhered to the surface thereof to perform washing. Immersion treatment is performed at about 10-100 deg.C, pref., for about 10-15min and, thereafter, washing is performed for about 10-15min before hot air drying. |
