Toyo Boseki Kabushiki Kaisha

Toyobo Co., Ltd.

Seiji Watanuki

Tooru Kitagawa

Yoshihiko Teramoto

Hidehiko Sakurai

Isamu Yamamoto

Kazutake Okamoto

Mitsuru Suzuki

Takahito Nakao

Tohru Uenishi

Hideo Sato

Yasuhiro Shiota

Hiroki Murase

Yusuke Shimizu

Takashi Ohkame

Kohei Kiriyama

Mayumi Akashi

Miyuki Yao

[Problem] To provide a membrane for the forward osmosis method, which keeps a high porosity, reduces concentration polarization by appropriately controlling the pore distribution, achieves both high water permeability and a self-supporting property, and has high chemical durability such that are membrane is applicable to various draw solutions. [Solution] A separation membrane having a structure inclined from an outer surface side to an inner surface side, a ratio between a thickness of a dense layer having a dense polymer density and a thickness of a coarse layer having a coarse polymer density being in a range of 0.25&#x2264;(the thickness of the coarse layer)/[(the thickness of the dense layer)+(the thickness of the coarse layer)]&#x2264;0.6, when measuring polymer density distribution in a thickness direction of the separation membrane by Raman spectroscopy.

Separation membrane, separation membrane element and separation membrane module

The present invention provides a composite separation membrane having a separation layer formed of SPAE on the surface of a porous support membrane wherein the porous support membrane and a coat of SPAE are firmly adhered with each other so that separation property and water permeation property continue for a long period. The present invention is a composite separation membrane having a separation layer on the surface of a porous support membrane, characterized in that said porous support membrane contains 50% by mass or more of polyphenylene ether, and that said separation layer is formed of a sulfonated polyarylene ether copolymer constituted from a repeating structure of a specific hydrophobic segment and a specific hydrophilic segment. The composite separation membrane of the present invention is suitable as a liquid treating membrane such as a nanofiltration membrane and a reverse osmosis membrane.

Composite separation membrane

To provide fibers which retain the excellent heat resistance and flame retardancy inherent in polybenzazole fibers and pyridobisimidazole fibers, have improved post-processability and neither necessitate considerable change in production process conditions nor require a high-temperature and long-time heating treatment. With respect to the polybenzazole fiber and pyridobisimidazole fiber, in an electron diffraction diagram of a surface layer part (from the surface to 1 &#x3bc;m) of the fibers, the fibers containing a crystal present in a state satisfying that S2/S1 is in a prescribed range, wherein S1 is a diffraction peak area derived from a crystal (200) plane and S2 is a diffraction peak area derived from a plurality of other crystal planes along an equatorial direction profile.

Polybenzazole fiber and pyridobisimidazole fiber

A method of preparing a precursor for a composite having wet strength of 2 to 50 kgf/mmand a mean surface void diameter of 0.01 to 2 &#x3bc;m by molding a solution of a rigid polymer having a concentration of 1 to 1.3 times the optical anisotropy lower limit solution concentration C2, thereafter rendering the solution non-flowable by absorbing a coagulant under a condition causing no solvent extraction and thereafter extracting the solvent, and a method of preparing a molecular composite having a mean thickness of 2 to 200 &#x3bc;m by impregnating this precursor for a composite with a solution of a polymer or reactive molecules.

Method of preparing composite from rigid polymer solution and composite film

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.

Cellulose acetate hemodialysis membrane

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.

Growing community of inventors

Otsu, Japan

Seiji Watanuki