SEMIPERMEABLE MEMBRANE SUPPORTING BODY

PROBLEM TO BE SOLVED: To provide a semipermeable membrane supporting body excellent in adhesive with a semipermeable membrane and hardly causing peeling and fracture of the semipermeable membrane, excellent in dimensional stability and hardly causing peeling and fracture, etc., of the semipermeable membrane when the membrane is used in a high pressure filtration, etc., capable of stably supporting the membrane even if filtering speed is high, excellent in surface smoothness and capable of forming a flat, uniform and smooth membrane having no and hardly causing a strike-through of a membrane forming liq. and capable of forming the membrane having no pinhole and to provide its production method. SOLUTION: This semipermeable membrane supporting body consisting of a nonwoven fabric having >=4.0km average lengthwise and crosswise breaking length at 5% extension and 0.2-10.0cc/cm .sec air permeability is used. This semipermeable membrane supporting body is formed by making a web by using preferably a polyester based fiber having double refractivity (Δn) of >=170 and 0.10-0.60g/d thermal shrinkage stress at 200 deg.C and a heat fusible binder fiber and subjecting the web to pressure treatment under heating.