| abstract |
The present invention is a composite semipermeable membrane comprising a base material, a support layer, and a separation functional layer, wherein the support layer comprises a thermoplastic resin having a porous structure, and particles, wherein the particles are: A cross section of the support layer, which is present in the thermoplastic resin and contains at least one material selected from the group consisting of diene-based polymers, acrylic-based polymers and ethylene-based polymers, and cut along the thickness direction of the support layer. In the range of 3 μm from the surface of the support layer in the thickness direction and 3 μm in the direction along the surface, the composite semipermeable membrane having 6 or more particles. |