Asahi Kasei Kabushiki Kaisha

Asahi Kasei Chemicals Corporation

Yuki Miki

Daisuke Okamura

Masatoshi Hashino

Hirokazu Fujimura

Provided is a porous hollow fiber membrane made of a thermoplastic resin, wherein a membrane thickness is 0.050 mm or larger and 0.25 mm or smaller, and when a strength coefficient is defined as K=(compressive strength)/((membrane thickness)/(inside diameter/2)), K=1.7 or more.

Porous hollow fiber membrane and method for producing porous hollow fiber membrane

The porous hollow fiber membrane of the present invention contains a thermoplastic resin, and includes a surface having a surface porosity of 32 to 60% and a fine pore diameter of 300 nm or less, and has a compressive strength of 0.7 MPa or more. The porous hollow fiber membrane of the present invention may include at least two layers, and in this case, the surface of one layer has a thickness of backbone of 0.3 to 20 &#x3bc;m and a fine pore diameter of 0.3 to 10 &#x3bc;m, and the surface of the other layer has a surface porosity of 32 to 60% and a fine pore diameter of 0.05 to 0.3 &#x3bc;m.

Porous hollow fiber membrane, method for producing same, and water purification method

Provided is a porous membrane which has a high water permeability performance, a high blocking performance, and a durability performance against loads of long-term and high operation pressures, which are suitable for filtering applications. The porous membrane includes one surface to be on a side of a filtrate; and the other surface to be on a side of a liquid to be filtered, wherein a surface pore diameter index of the one surface is 2.5 or more, the surface pore diameter index being determined by dividing a pore diameter in a top surface by a pore diameter in a second top surface.

Porous membrane

Provided is a porous membrane having a high blocking performance suited for filtration application as well as being excellent in water permeability performance, which is capable of providing stable filtering operation over a long period of time. The porous membrane has a cross-sectional pore size index of 40 or more in a region where a membrane thickness position ranges from 0.1 to 0.2 within the membrane thickness which is normalized by defining one surface position as 0 and the other surface position as 1 and divided into ten regions in the membrane thickness direction, the cross-sectional pore size index being calculated by: Cross-Sectional Pore Size Index=(Cross-Sectional Pore Size in the Range)/(Pore Size of the One Surface).

A porous membrane has a thickness of 150 &#x3bc;m or greater. The pore diameters of a first surface are smaller than the pore diameters of a second surface. The average value of the pore diameters of the first surface is 60 nm or less, and the coefficient of variation of the pore diameters is 10% or greater and 50% or less.

Porous membrane and process for producing porous membrane

The present invention relates to a multiporous hollow-fiber membrane containing a thermoplastic resin, in which an aspect ratio of outer surface pores is 10 or more, an aspect ratio of inner surface pores is 1 to 5, and a thickness of a polymer backbone forming the outer surface pores is 1 &#x3bc;m to 20 &#x3bc;m.

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Tokyo, Japan

Yuki Miki