PURPOSE: To selectively permeate the specified gas in a gaseous mixture through the membrane by forming the membrane with a soluble aromatic polyimide consisting of the repeating unit shown by the specified general formula.
CONSTITUTION: A gas separation hollow-fiber membrane is formed with a soluble aromatic polyimide consisting of the repeating unit shown by formula I. In this case, 40-90mol% of the R in the formula I is a tetravalent unit R1 based on the diphenylhexafluoropropane structure shown by formula II, the 10-40mol% is tetravalent unit R2 based on a phenyl structure shown by formula III, and the remainder of R is a tetravalent unit R3 based on a biphenyl structure shown by formula IV. The 35-100mol% of A in the formula I is a bivalent unit A1 shown by formula V (R and R' are hydrogen or org. groups, and n is 0, 1 or 2) and/or a bivalent unit A shown by the formula VI (R and R' are the same as in the formula V, and X is -CH2- or -CO-). The remainder of A is a bivalent unit A3 obtained by removing an amino group from an aromatic diamine.
YOSHINAGA TOSHIMUNE
HOSHINO HARUTOSHI
ASANUMA SHINJI
