Abstract: The present invention provides a hollow fiber membrane where the membrane strength and pressure resistance to pressurization from the dialysate side is ensured, the retaining rate of water permeability after the repeated pressure load from outside is high, the resistance to the pressure from outside is excellent and the assembling property into module (low leakage rate at the adhered part) is satisfactory at the same time. The present invention also provides a method for manufacturing the same, and a blood purification module.

Abstract: The present invention provides a hollow fiber membrane where the membrane strength and pressure resistance to pressurization from the dialysate side is ensured, the retaining rate of water permeability after the repeated pressure load from outside is high, the resistance to the pressure from outside is excellent and the assembling property into module (low leakage rate at the adhered part) is satisfactory at the same time. The present invention also provides a method for manufacturing the same, and a blood purification module. An annealing spinning method was found where a spinning dope is discharged from a nozzle into a coagulation bath, an appropriate elongation is applied so as to enhance the membrane strength, an elongation is continued during a water-washing step so as not to relax the elongation, and no elongation is applied during drying whereby the strain is relaxed.

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.