Patent ID: 9211497
Filing Date: 2015-12-15
Classification: B01D,C08L

Abstract:
1. An asymmetric gas separation membrane produced by heating an asymmetric gas separation membrane made of a polyimide substantially consisting of repeating units represented by the following general formula (1) at a temperature of T tr within the range: wherein T wherein a permeation rate of methanol vapor (P′ a ratio of a permeation rate of methanol vapor to a permeation rate of dimethyl carbonate vapor (P′ the polyimide has a softening point of 245° C. or higher, wherein in general formula (1), A represents a tetravalent residue having an aromatic ring, wherein 60 to 100 mol % of the tetravalent residue having an aromatic ring represented by A in general formula (1) is a tetravalent residue based on a biphenyl structure represented by chemical formula (A1) and in general formula (1), B mainly represents a divalent residue represented by the following chemical formula (B1) and/or a divalent residue represented by the following chemical formula (B2): wherein in chemical formula (B2), Ar represents one or more divalent residues selected from the group consisting of the residues represented by chemical formulas (Ar1) to (Ar6)