Asahi Kasei Chemicals Corporation

Fujifilm Corporation

Dowa Electronics Materials Co., Ltd.

Asahi Kasei Medical Co., Ltd.

Asahi Kasei Kabushiki Kaisha

Satoshi Shiki

Hiroyuki Suzuki

Toshio Tada

Noboru Kubota

Hirohisa Omoto

Shuji Kaneda

Chihiro Kato

Yuukou Seki

Hiroyoshi Ohya

Makiko Hattori

Provided is an Al-containing hexagonal ferrite magnetic powder which produces an excellent durability-improving effect on a magnetic recording medium, wherein uniform pulverization of the magnetic powder can be easily achieved by dispersion treatment in preparation of a magnetic coating material even in cases where the magnetic powder has a small primary particle size or has a composition which is likely to produce hard secondary particles. The magnetic powder for a magnetic recording medium is an Al-containing hexagonal ferrite magnetic powder having an Al/Fe molar ratio of 0.030 to 0.200, and has a particle size distribution in which the volume ratio of particles having a particle size of 30 μm or more as measured by a laser diffraction particle size distribution analyzer with a dispersion pressure of 100 kPa is 5.0% or less, and an activation volume Vact of 1800 nmor less.

Magnetic powder for magnetic recording medium

A hollow fiber membrane module comprising a bundle of hollow fiber membranes, a housing, an adhesive fixation layer, an inlet and outlet, at least one bias regulating member, and at least one straightening cylinder, in which the bias regulating member is contained in the adhesive fixation layer, the adhesive fixation layer comprises an outer end surface and an inner end surface inside the straightening cylinder, at least some of spaces between the hollow fiber membranes are at least three times as large as an outer diameter of the hollow fiber membrane on the outer end surface of the adhesive fixation layer, and the spaces between the hollow fiber membranes and a space from the hollow fiber membranes to the straightening cylinder are all less than three times as large as the outer diameter of the hollow fiber membrane on the inner end surface of the adhesive fixation layer.

Hollow fiber membrane module and filtering method

A porous membrane with the membrane wall constructed of a hydrophobic polymer and a hydrophilic polymer, wherein when the membrane wall is divided into 3 sections in the film thickness direction to form region 'a' containing one wall surface A of the membrane wall, region 'c' containing the other wall surface C and region &#x201c;b&#x201d; between region &#x201c;a&#x201d; and region &#x201c;c&#x201d;, the hydrophilic polymer content ratio Cin region &#x201c;a&#x201d; is greater than the hydrophilic polymer content ratio Cin region &#x201c;c&#x201d;, and the mean pore size of the wall surface C is larger than the mean pore size of the wall surface A.

Porous membrane, process for producing porous membrane, process for producing clarified liquid, and porous-membrane module

The present invention provides a PVDF porous film and method for producing it, which has high water permeability and high chemical resistance to washing chemicals and the like that has been difficult to realize with conventional polymer porous films, and which can be used over a prolonged period of time, and a method of producing the same and the like. Namely, the present invention provides a porous film in which the degree of crystallization of the PVDF resin is 50% or more but not more than 90%, and the product of the degree of crystallization of the PVDF resin and the specific surface area of the film is 300 (%&#xb7;m/g) or more but not more than 2000 (%&#xb7;m/g).

Highly durable porous PVDF film, method of producing the same and washing method and filtration method using the same

Use of a porous hollow fiber membrane for producing a clarified biomedical culture medium by a method including a filtration step of distributing a biomedical culture medium over the porous hollow fiber membrane, a tube wall of the hollow fiber membrane being constituted of a blend of a hydrophobic polymer and polyvinylpyrrolidone. A content of the polyvinylpyrrolidone is not lower than 0.2% by mass and not higher than 3% by mass relative to a total mass of the porous hollow fiber membrane, and, when the tube wall is divided in a membrane-thickness direction equally into three regions, a content of the polyvinylpyrrolidone in an outer circumferential region including an outer face is higher than a content of the polyvinylpyrrolidone in an inner circumferential region including an inner face, and an average pore size in the inner face is larger than an average pore size in the outer face.

Use of porous hollow-fiber membrane for producing clarified biomedical culture medium

Growing community of inventors

Tokyo, Japan

Satoshi Shiki