Abstract: A hollow fiber membrane element, comprising: a core tube comprising a side face having a plurality of pores; and a hollow fiber membrane group consisting of a plurality of hollow fiber membranes disposed around the core tube, the hollow fiber membrane element being a both open-ended type hollow fiber membrane element in which both ends of the core tube and the plurality of hollow fiber membranes are open. The hollow fiber membrane group includes a first hollow fiber membrane layer composed of a plurality of first hollow fiber membranes disposed so as to surround the core tube and a second hollow fiber membrane layer composed of a plurality of second hollow fiber membranes disposed so as to surround the first hollow fiber membrane layer, and a permeability coefficient of the plurality of first hollow fiber membranes is smaller than a permeability coefficient of the plurality of second hollow fiber membranes.

Abstract: A hollow fiber membrane module includes one pressure vessel, and at least one hollow fiber membrane element loaded in the pressure vessel. Each of the element includes a plurality of hollow fiber membranes each having openings at both ends, a bypass tube, and a supply port and a discharge port provided on one end side in a longitudinal direction. The supply port is in communication with inflow-side openings of hollow fiber membranes. The bypass tube is provided in the longitudinal direction of the element, has an inflow port at an end portion on a side of outflow-side openings of the hollow fiber membranes, and has an outflow port at an end portion on a side of the inflow-side openings of the hollow fiber membranes. The outflow-side openings of hollow fiber membranes are in communication with the inflow port, and the outflow port is in communication with the discharge port.

Abstract: A hollow fiber membrane element, comprising: a core tube comprising a side face having a plurality of pores; and a hollow fiber membrane group consisting of a plurality of hollow fiber membranes disposed around the core tube, the hollow fiber membrane element being a both open-ended type hollow fiber membrane element in which both ends of the core tube and the plurality of hollow fiber membranes are open. The hollow fiber membrane group includes a first hollow fiber membrane layer composed of a plurality of first hollow fiber membranes disposed so as to surround the core tube and a second hollow fiber membrane layer composed of a plurality of second hollow fiber membranes disposed so as to surround the first hollow fiber membrane layer, and a permeability coefficient of the plurality of first hollow fiber membranes is smaller than a permeability coefficient of the plurality of second hollow fiber membranes.

Abstract: A hollow fiber membrane module includes one pressure vessel, and at least one hollow fiber membrane element loaded in the pressure vessel. Each of the element includes a plurality of hollow fiber membranes each having openings at both ends, a bypass tube, and a supply port and a discharge port provided on one end side in a longitudinal direction. The supply port is in communication with inflow-side openings of hollow fiber membranes. The bypass tube is provided in the longitudinal direction of the element, has an inflow port at an end portion on a side of outflow-side openings of the hollow fiber membranes, and has an outflow port at an end portion on a side of the inflow-side openings of the hollow fiber membranes. The outflow-side openings of hollow fiber membranes are in communication with the inflow port, and the outflow port is in communication with the discharge port.

Abstract: The present invention provides a polysulfone type hollow fiber membrane which is reliable in safety and stability of performance and is easily incorporated into a module, and thus can be suitably used in a highly water permeable blood purifier for use in a therapy of chronic renal failure. The present invention relates to a polysulfone type selectively permeable hollow fiber membrane comprising a polysulfone type resin and a hydrophilic polymer as main components, and characterized in that (A) the content of the hydrophilic polymer in the uppermost layer of a surface of the polysulfone type hollow fiber membrane on the blood-contacting side is at least 1.1 times larger than the content of the hydrophilic polymer in the proximate layer of the surface on the blood-contacting side, and (B) the content of the hydrophilic polymer in the uppermost layer of the other surface of the polysulfone type hollow fiber membrane, i.e., the reverse side of the surface on the blood-contacting side, is at least 1.

Abstract: The present invention provides a highly water permeable hollow fiber membrane type blood purifier for medical use, which is excellent in safety and module-assembling ease and which has a high water permeability suitable for use in therapy of chronic renal failure. The present invention relates to a highly water-permeable hollow fiber type blood purifier comprising hydrophobic polymer hollow fiber membranes each of which contains a hydrophilic polymer, characterized in that the amount of the hydrophilic polymer eluted from the hollow fiber membrane is 10 ppm or less; in that the ratio of the hydrophilic polymer in the outer surface of the hollow fiber membrane is 25 to 50 mass %; in that the burst pressure of the hollow fiber membrane is 0.5 MPa or higher; and in that the coefficient of water permeability of the blood purifier is 150 ml/m2/hr./mmHg or higher.

Abstract: The present invention provides polysulfone-based hollow fiber membranes having high water permeable performance and for use in therapy of chronic renal failures, said hollow fiber membranes having high safety and high stability in performance and being excellent in module-fabricating workability. The present invention also provides a process for manufacturing the same. The present invention relates to a bundle of a plurality of selectively permeable polysulfone-based hollow fiber membranes wherein the amount of a hydrophilic polymer eluting from each hollow fiber membrane is not larger than 10 ppm, and wherein the content of the hydrophilic polymer in the outer surface of the hollow fiber membrane is 25 to 50 mass %, and this bundle is characterized in that any of extracted solutions from ten fractions of said bundle, obtained by dividing the bundle at substantially regular intervals along the lengthwise direction, shows a maximum value of smaller than 0.

Abstract: The present invention provides a highly water permeable hollow fiber membrane type blood purifier for medical use, which is excellent in safety and module-assembling ease and which has a high water permeability suitable for use in therapy of chronic renal failure. The present invention relates to a highly water-permeable hollow fiber type blood purifier comprising hydrophobic polymer hollow fiber membranes each of which contains a hydrophilic polymer, characterized in that the amount of the hydrophilic polymer eluted from the hollow fiber membrane is 10 ppm or less; in that the ratio of the hydrophilic polymer in the outer surface of the hollow fiber membrane is 25 to 50 mass %; in that the burst pressure of the hollow fiber membrane is 0.5 MPa or higher; and in that the coefficient of water permeability of the blood purifier is 150 ml/m2/hr./mmHg or higher.

Abstract: The present invention provides a plasma separation filter capable of easily, speedily and safely separating plasma from a small quantity of blood without damaging blood cell components in the blood. The plasma retains the same protein concentration as in the blood. The present invention also provides a method using such a filter and an apparatus comprising such a filter. The filter of the present invention comprises a micro fiber medium formed of micro fibers with an average hydraulic radius of 0.5 &mgr;m to 3.0 &mgr;m. Such a micro fiber medium is placed in a container having an inlet and an outlet so that a ratio (L/D) of a blood flow passage length (L) to a blood flow passage diameter (D) is 0.15 to 6. The present invention provides such a filter, a plasma separation method using the filter, and a plasma separation apparatus comprising the filter. The present invention can significantly contribute to promote the automation and enhance speediness and safety in clinical tests.

Abstract: A blood purification membrane having a membrane thickness of 10 to 35 .mu.m, an inner diameter of 100 to 300 .mu.m, a porosity of 50 to 85%, a water permeability (ultrafiltration rate) at 37.degree. C. of not less than 20 ml/m.sup.2 .multidot.Hr.multidot.mmHg and a sieving coefficient of albumin of not more than 0.01, a substantially homogeneous interior structure, and a smooth surface structure. A process for producing the membrane and a module are also provided.

Abstract: A cellulose acetate membrane composed of a mixture comprising a cellulose triacetate and a cellulose diacetate and having an improved heat stability, which does not substantially show a melting peak of cellulose diacetate but substantially shows a melting peak of cellulose triacetate, in a differential thermal analysis. By mixing a cellulose triacetate and a cellulose diacetate at an appropriate ratio, crystallization or orientational crystallization of each component due to a high pressure stream sterilization can be avoided and a cellulose acetate membrane with improved water permeability and sieving coefficient of myoglobin after a high pressure steam sterilization can be obtained.

Abstract: A cellulose acetate membrane composed of a mixture comprising a cellulose triacetate and a cellulose diacetate and having an improved heat stability, which does not substantially show a melting peak of cellulose diacetate but substantially shows a melting peak of cellulose triacetate, in a differential thermal analysis. By mixing a cellulose triacetate and a cellulose diacetate at an appropriate ratio, crystallization or orientational crystallization of each component due to a high pressure steam sterilization can be avoided and a cellulose acetate membrane with improved water permeability and sieving coefficient of myoglobin after a high pressure steam sterilization can be obtained.