Patent ID: 7081202

Claim:
A composite semipermeable membrane comprising a porous support membrane and a thin film formed thereon, said thin film comprising a polyamide based resin constituted by a unit obtained by condensation reaction of a diamine component with a non-hetero aromatic polyfunctional acid halide having 2 or more valences, said unit being represented by the following general formulas (I) and/or (II), said polyamide based resin comprising said unit at a ratio of 50% or more by mole: wherein R 11 represents an alkylene group which has 2 to 10 carbon atoms and may contain —O—, —S—, or —NR—, wherein R represents a hydrogen atom or a lower alkyl group,and R 12 and R 13 each independently represent an aromatic hydrocarbon group which may have a substituent, or a hydrogen atom, at least one of R 12 or R 13 represents an aromatic hydrocarbon group which may have a substituent, and R 14 represents a bivalent non-hetero aromatic group which may have a substituent, and wherein R 21 represents an alkylene group which has 2 to 10 carbon atoms and may contain —O—, —S—, or —NR—, wherein R represents a hydrogen atom or a lower alkyl group, R 22 and R 23 each independently represent an aromatic hydrocarbon group which may have a substituent, or a hydrogen atom, at least one of R 22 or R 23 represents an aromatic hydrocarbon group which may have a substituent, and R 24 represents a trivalent non-hetero aromatic group which may have a substituent.