Polysulfone-based hollow fiber membrane and process for manufacturing the same
AssigneeKuraray Co., Ltd.
InventorsIchiro Kawata, Takehiko Okamoto, Hiroyuki Akasu, Kensaku Komatsu
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Abstract
The polysulfone hollow fiber membrane of the invention has an inner dense skin layer composed of a polysulfone and a less amount of a polyvinylpyrrolidone, a content of the polyvinylpyrrolidone in the dense skin layer being higher than that in an outer surface layer. This membrane has excellent biocompatibility and antithrombogenetic ability and is, therefore, useful in body fluid treatment, such as hemodialysis, hemofiltration and hemoconcentration, without clogging with thrombi.
Claims11
A polysulfone-based hollow fiber membrane having an asymmetric structure comprising a skin layer on its inner surface and an outer surface layer, said membrane comprising predominantly a polysulfone-based polymer, at least 1% by weight of polyglycol, and 1-8% by weight of a vinylpyrrolidone-based polymer, said skin layer comprising a polysulfone-based polymer and a vinylpyrrolidone-based polymer in a weight ratio of the former to the latter of between 90/10 and 60/40, and a ratio of the weight percent vinylpyrrolidone-based polymer in said skin layer to the weight percent vinylpyrrolidone-based polymer in an outer surface layer of the membrane of at least 1.1.
A process for manufacturing polysulfone-based hollow fiber membranes, which comprises the steps of:
- extruding, from an annular orifice, a dope comprising a polysulfone-based polymer, a polyglycol having an average molecular weight of 200-6000 and a vinylpyrrolidone-based polymer having an average molecular weight of at least 10,000, mixed and dissolved in a solvent;
- feeding a liquid containing 0.1-4% by weight of a vinylpyrrolidone-based polymer into a tubular flow of said dope being extruded from said annular orifice to form a polysulfone-based hollow fiber membrane;
- and
- treating the resulting polysulfone-based hollow fiber membrane with a solution acting as a poor solvent for said polysulfone-based polymer in such a manner that a ratio of the weight percent vinylpyrrolidone-based polymer in a skin layer on an inner surface to the weight percent vinylpyrrolidone-based polymer in an outer surface layer, of said hollow fiber membrane, is adjusted to at least 1.1.
Dependencies are inferred from the claim text.