Patent ID: 11207645

Abstract:
The purpose of the present invention is to provide: a composite semipermeable membrane which has three excellent properties, namely, excellent ionic substance rejecting property, excellent nonionic substance rejecting property and excellent water permeability in a practically balanced manner, and a spiral wound separation membrane element which comprises this composite semipermeable membrane. A composite semipermeable membrane according to the present invention is obtained by forming a skin layer that contains a polyamide-based resin on a surface of a porous support, and is configured such that: the polyamide-based resin is obtained by polymerizing a polyfunctional acid halide component and a polyfunctional amine component; the polyfunctional amine component contains m-phenylenediamine and at least one diamine compound represented by general formula (1); and a ratio (mol %) of a segment (A) derived from m-phenylenediamine and a segment (B) derived from the diamine compound in the polyamide-based resin is 99.9:0.1 to 98:2 (segment (A):segment (B)).