| abstract |
PURPOSE: To efficiently prepare the subject film excellent in separating oxygen from nitrogen by mixing a specific tetrahalobisphenol polycarbonate with a specific solvent, heating the mixture, extruding it into a film, and cooling quickly to separate the solvent. n CONSTITUTION: A bisphenol polycarbonate in which at least 25 wt.% of the bisphenol part is tetrahalogenated with chlorine or bromine is prepared. The polycarbonate is mixed with a solvent for the polycarbonate, such as morpholine substituted with glycol ether of the formula (R3 is methyl or ethyl; (r) is 1-20), dimethyl ketone, diethyl ketone, alkyl, formine or a morpholine whose N is substituted with an alkanoyl. The mixture is subsequently heated, and the heating mixture is extruded into a film of a desired shape. The film formed is run through one or more rapid cooling zones, in the zone the mixture phase is separated and most of the solvent is removed from the film to obtain the objective film which has a distinguishing area where oxygen can be separate from nitrogen. n COPYRIGHT: (C)1990,JPO |