| 摘要 |
PURPOSE:To obtain an ultrafiltration membrane having high antibacterial property causing extremely small amt. of adsorption of hydrophobic object of treatment by using a polyvinyl formal resin with a restricted molecular weight distribution without adding any pore forming agent, etc. CONSTITUTION:A dope having about 8-15wt.% concn. of a polyvinyl formal resin having a recurrent unit expressed by formula I is prepd. using N,N- dimethyl formamide as solvent. The dope is applied uniformly to polyester nonwoven fabric, acid., and obtd. coated fabric is then dipped in a coagulation bath contg. water at about 0-45 deg.C to transfer the solvent in the dope into a liquid phase in the coagulation bath. Thus, the dope is gelled, and an ultrafiltration film is formed by a wet film forming method. By this method, an ultrafiltration membrane consisting of polyvinyl formal having extremely high hydrophilic property and 1,000,000-3,000,000 molecular weight restricted distribution is obtd. |
