Abstract: Disclosed is a semipermeable membrane support and a process for making the same. The support is formed of a non-woven fabric of a laminated structure having a low density layer with an air permeability of 5 to 50 cc/cm.sup.2 /sec and a high density layer with an air permeability of 0.1 cc/cm.sup.2 to 5 cc/cm.sup.2 /sec, the non-woven fabric having an overall air permeability of 01 to 4.5 cc/cm.sup.2 /sec. The process for preparing such a support consists of laminating a dry processed web, which is entirely of polyester fibers containing 20 to 80% of undrawn polyester fiber or conjugate polyester fibers having an average fiber denier of 1 to 3 denier formed through a dry process, and an un-press-treated wet processed web, which is entirely of polyester fibers containing 30 to 90% of undrawn polyester fibers or conjugate polyester fibers having a fiber denier of 0.1 to 1.

Abstract: Disclosed is a semipermeable membrane support and a process for making the same. The support is formed of a non-woven fabric of a laminated structure having a low density layer with an air permeability of 5 to 50 cc/cm.sup.2 /sec and a high density layer with an air permeability of 0.1 cc/cm.sup.2 /sec to 5 cc/cm.sup.2 /sec, the non-woven fabric having an overall air permeability of 01 to 4.5 cc/cm.sup.2 /sec. The process for preparing such a support consists of laminating a dry processes web, which comprises entirely polyester fibers containing 20 to 80% of undrawn polyester fiber or conjugate polyester fibers having an average fiber denier of 1 to 3 denier formed through a dry process, and an un-press-treated wet processed web, which comprises entirely polyester fibers containing 30 to 90% of undrawn polyester fibers or conjugate polyester fibers having fiber denier of 0.1 to 1.