Hollow fiber membrane for an artificial lung

Claim 1

A porous polypropylene hollow fiber membrane of a circular cross section 150 to 300 μm in inside diameter and 10 to 150 μm in wall thickness for use in an atificial lung, which hollow fiber membrane is characterized by having an inner surface aperture ratio in the range of 10 to 30%, a porosity in the range of 10 to 60%, and an oxygen flux in the range of 100 to 1,000 liters/min.m 2 .atm. and inducing no leakage of blood plasma within 30 hours use with circulation of blood therethrough; said inner surface of the hollow fiber having a solid phase of particulate polypropylene intimately fused tightly in the pattern of a continuous phase while partly exposed on the surface; the inside of the hollow fiber membrane having particulate polypropylene interlinked in the axial direction of fiber to form a multiplicity of polypropylene masses mutually bound with fibers of polypropylene; and the outer surface of the hollow fiber membrane having a solid phase of threads of polypropylene containing particulate polypropylene reticularly bound coarsely; and wherein those solid phases form interstices therebetween; the interstices communicating with one another in a three-dimensional network to give rise to continuous holes communicating the inner surface with the outer surface; an average particle diameter of the particulate polypropylene being in the range of 0.1 to 1.0 μm, the average pore diameter on the inner surface being in the range of 0.1 to 1.0 μm, a maximum value of the pore diameter distribution curve of the whole membrane being in the range of 0.02 to 0.2 μm, and the specific area being in the range of 10 to 40 m 2 /g.