| 摘要 |
<p>PURPOSE:To obtain a porous membrane having a high water flux, excelling in heat resistance, chemical resistance storage stability and handleability and suited for treatment of condensate, treatment of water for supercritical pressure boilers, comprising a polyether-imide having specified repeating units. CONSTITUTION:A saturated vapor or mist-containing vapor of a poor solvent (C) which is miscible with component B and does not dissolve component A (e.g., water) is fed at a rate of 0.1-1,000mg/sec and forcibly contacted with at least either surface of a thin-film object formed from a 20-40wt.% concentration polymer solution formed by dissolving a polyether-imide (A) having repeating units of the formula (wherein n is 1-7), obtained by polycondensing phenoxyphenyldicarboxylic anhydride with phenylenediamine, in a good solvent (B) such as N-methylpyrrolidone to obtain a porous membrane of an average pore diameter <=0.20mu, a thickness >=50mu and a water flux >=15ml/cm<2>.min.10psi.</p> |
