Abstract: Disclosed is a hydrophilic material characterized in that the material comprises a copolymer composed of a monomer (A) having a polyalkylene oxide unit and a polymerizable carbon-carbon double bond in its molecule, a methacrylic ester monomer or an acrylic ester monomer (B) and a monomer (C) having a polymerizable carbon-carbon double bond other than the monomers (A) and (B), and the content of the monomer (C) is not less than 5% by weight and not more than 90% by weight, and a semipermeable membrane made therefrom. The present invention provides a hydrophilic material which can be dissolved in a solvent, can be easily formed and is excellent in antithrombotic and antifouling properties, and further provides an antithrombotic material and a semipermeable membrane. These materials can be appropriately used in the medical field and as water-absorbent and antifouling materials.

Abstract: An anti-thrombogenic blood treating system, comprising selectively permeable hollow yarn membranes made of a composition containing a copolymer with polyethylene oxide component, and headers, catheters and circuits respectively covered on the blood contact surface with a heparinized hydrophilic copolymer containing vinyl chloride as a component monomer or a hydrophilic copolymer with polyethylene oxide component, in combination. All the blood contact surfaces are made anti-thrombogenic to allow, for the first time, the long-time extracorporeal circulation without intracorporeal administration of heparin.