Hydrophilic composite porous membrane, a method of producing the plasma

Abstract

A novel hydrophilic composite porous membrane is obtained by applying a specific copolymer solution onto the overall surface of an oriented polyolefin membranous matrix comprising a plurality of microfibrils and a plurality of knotted portions cross-connected to the microfibrils, followed by drying. The copolymer is water-insoluble and is comprised of hydrophilic monomeric units and hydrophobic monomeric units in a specific ratio. In the obtained composite porous membrane, the microfibrils are bonded together by means of the copolymer, thereby forming bundles and a coat of the copolymer is formed on the overall surface of the bundles and knotted portions. The membrane has therewithin pores which are substantially elliptic in the cross section taken along the same direction as the longitudinal direction of the microfibril bundles and has on both surfaces thereof openings which are substantially elliptic as viewed against the surface of the membrane. The membrane exhibits a high permeability for high molecular weight components and has high hydrophilic properties, so that the membrane is especially useful for plasma separation.