Toyo Boseki Kabushiki Kaisha

Toyobo Co., Ltd.

The Dow Chemical Company

Tooru Kitagawa

Yasuo Ohta

Yoshihiko Teramoto

Yoshimitsu Sakaguchi

Godo Sakamoto

Michio Ishitobi

Hiroki Murase

Seiji Watanuki

Syoji Oda

Junsuke Morita

Hideki Sugihara

Masao Higashi

Yoshikazu Tanaka

Satoshi Maeda

Chieh-Chun Chau

Naoki Watanabe

Kazuyuki Yabuki

Takahiro Nakajima

Jang-hi Im

Shiro Hamamoto

Satoshi Takase

Kota Kitamura

Hisato Kobayashi

Takaharu Ichiryu

Hideaki Ishihara

Yasunori Fukushima

Mitsuhiro Sakuda

Satoru Nakagawa

Shigenori Nagahara

Fumikazu Yoshida

Yukihiro Nomura

Naohiko Takimoto

Masahiko Nakamori

Takahito Nakao

Yusuke Shimizu

Kohei Kiriyama

Kazuo Katayose

Katsuhiko Kageyama

Atsushi Kaji

Masaki Fuchikami

Miyako Noshiro

Haruhiko Kohyama

Toshiyuki Tsuchiya

Kenichi Funaki

Norifumi Shimada

Miyuki Yao

Mayumi Akashi

[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 porous polymer flat-sheet membrane for MBR wherein surface of the porous polymer membrane is kept hydrophilic for a long period and high water permeability and anti-fouling properties are kept. A porous polymer flat-sheet membrane for MBR comprising a hydrophobic porous polymer membrane forming a network structure and a sheet substrate supporting it, characterized in that at least surface of the porous polymer membrane is coated and fixed with an insolubilized hydroxypropyl cellulose, that a ratio of the hydroxypropyl cellulose to the porous polymer membrane is 0.4 to 1.0% by weight and that, when NMR spectrum of the hydroxypropyl cellulose coated on and fixed to the membrane is measured using a nuclear magnetic resonance apparatus (proton NMR), an intensity ratio (B/A) of a spectral peak (B) appearing at 4.12 ppm to a spectral peak (A) appearing at 3.75 ppm is 12 to 30%.

Porous polymer flat-sheet membrane

A non-woven fabric which is excellent in thermal resistance, mechanical strength, and thermal dimensional stability for applications exposed to high temperature circumstance and has an extremely large surface area and exhibit an excellent filter performance is obtained. The non-woven fabric is composed of polyimide fibers which are obtained by polycondensation of at least an aromatic tetracarboxylic acid and an aromatic diamine having a benzoxazole structure and have a fiber diameter in the range of 0.001 &#x3bc;m to 1 &#x3bc;m. The non-woven fabric is obtained by the steps of preparing a polyamic acid by polycondensation of an aromatic tetracarboxylic acid and an aromatic diamine having a benzoxazole structure, and electro-spinning the polyamic acid to form a polyimide precursor non-woven fabric; and imidizing a polyimide precursor fiber bundle.

Polyimide nonwoven fabric and process for production thereof

To provide a reverse osmosis membrane where both salt rejection rate and water permeability required for wastewater treatment are achieved in a high level in spite of using the materials having excellent resistance to chemicals (resistance to alkali and to chlorine). A reverse osmosis membrane for wastewater treatment comprising a sulfonated poly(arylene ether sulfone) polymer containing a constituting component represented by the following formula [I], characterized in that, in a proton nuclear magnetic resonance spectrum where water molecules in the membrane are measured using the reverse osmosis membrane in a water-containing state, the relation between the chemical shift A (ppm) of spectral peak top derived from bound water and the chemical shift B (ppm) of spectral peak top derived from bulk water satisfies (B&#x2212;0.36)&#x2266;A&#x3c;(B&#x2212;0.30): 

Reverse osmosis membrane for wastewater treatment

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

This invention provides a polyester and a polyester molded product, which, while maintaining color tone, transparency, and thermal stability, can realize a high polycondensation rate, are less likely to cause the production of polycondensation catalyst-derived undesired materials, and can simultaneously meet both quality and cost effectiveness requirements, which can exhibit the characteristic features, for example, in the fields of ultrafine fibers, high transparent films for optical use, or ultrahigh transparent molded products. These advantages can be realized by using, in the production of a polyester in the presence of an aluminum compound-containing polyester polycondensation catalyst, an aluminum compound having an absorbance of not more than 0.0132 as measured in the form of an aqueous aluminum compound solution, prepared by dissolving the aluminum compound in pure water to give a concentration of 2.7 g/liter in terms of the amount of aluminum element, under conditions of cell length 1 cm and wavelength 680 nm.

Process for producing polyester, polyester produced using said process, and polyester molded product

To provide a novel high strength polyethylene multifilament which consists of a plurality of filaments having high strengths and uniform internal structures, and showing a narrow variation in the strengths of the monofilaments, and which has been difficult to be provided by the conventional gel spinning method. A high strength polyethylene multifilament consisting of a plurality of filaments which are characterized in that the crystal size of monoclinic crystal is 9 nm or less; the stress Raman shift factor is &#x2212;5.0 cm/(cN/dTex) or more; the average strength is 20 CN/dTex or higher; the knot strength retention of each monofilament is 40% or higher; CV indicating a variation in the strengths of the monofilaments is 25% or lower; the elongation at break is from 2.5% inclusive to 6.0% inclusive; the fineness of each filament is 10 dTex or less; and the melting point of the filaments is 145&#xb0; C. or higher.

High strength polyethylene fiber

A composite ion exchange membrane having a high swelling resistance and being superior in mechanical strength and ion conductivity can be provided by means of an composite ion exchange membrane including an ion exchange resin composition and a support membrane having a continuous pore penetrating the support membrane, wherein the support membrane is one which accepts the ion exchange resin composition within the pore, and wherein the ion exchange resin composition is one which contains an ion exchange resin containing, as a main component, an aromatic polyether and/or its derivative, the aromatic polyether being obtained by mixing a compound having a specific structure, an aromatic dihalogenated compound and a bisphenol compound with a carbonate and/or a bicarbonate of an alkali metal and polymerizing the mixture in an organic solvent.

Composite ion-exchange membrane

A high strength polyethylene filament, wherein said filament has a fineness of 1.5 dtex or less as a monofilament, a tensile strength of 15 cN/dtex or more and a tensile elastic modulus of 300 cN/dtex or more, and, the rate of dispersion-defective fibers cut from the filament is 2% or less, is disclosed, and a high strength polyethylene filament, wherein said filament has a tensile strength of 15 cN/dtex or more and a tensile elastic modulus of 300 cN/dtex or more, and, a long period structure of 100 &#x212b; or less is observed in an X-ray small angle scattering pattern is disclosed.

A polybenzazole fiber having a compression strength is not less than 0.5 GPa, which contains a carbon nanotube having an outer of not more than 20 nm and a length of 0.5 &#x3bc;m-10 &#x3bc;m inside the fiber in a proportion of 1-15% by weight. Such polybenzazole fiber has conventionally unavailable high strength and high elastic modulus at the same time, as well as a specific fine fiber structure, and is useful as various industrial materials.

Polybenzazole fiber

Polybenzazole fibers wherein the mean square roughness of the fiber surface is 20 nm or less, or polybenzazole fibers wherein the X-ray meridian diffraction half-height width factor is 0.3&deg;/GPa or less, and their utilization such as shock-resistant members and heat-resistant felt, etc.

Polybenzazole fibers and their utilization

A polybenzazole fiber obtained through heat treatment, which has a high tensile modulus of not less than 300 GPa and a tensile strength of not less than 5.0 GPa, said fiber being characterized by an X-ray analysis by a fine structure thereof of at least one of the following (1) and (2):

Polybenzazole fiber having high tensile modulus and process of

A polybenzazole fiber characterized by having an elastic modulus of not less than 1350 g/d and requiring not longer than 10 minutes to reduce its water content from 2.0% to 1.5%, when determined using a thermogravimetric analyzer at 110.degree. C. after moisture absorption of not less than 2.0% of a fiber, and a method for manufacturing such a polybenzazole fiber, comprising extruding a spinning dope comprising polybenzazole and a polyphosphoric acid from a spinneret to give a dope filament, and cooling the dope filament to not more than 50.degree. C., followed by coagulation and washing. According to the method of the present invention, a polybenzazole fiber showing less decrease in strength by rapid heating can be provided.

Polybenzazole fiber and method for production thereof

The present invention provides processes for producing polybenzazole fibers where a spinning dope containing a polybenzazole polymer in an acid solvent is extruded through a spinning nozzle, followed by coagulation in a coagulating medium and washing with a fluid capable of dissolving the acid solvent; thereafter, in one process, the fiber obtained by the coagulation under specific conditions and the subsequent washing is dried in a heating zone with at least 80% part based on the total length thereof being set at a temperature of 240.degree. C. or higher, and in the other process, the fiber obtained by the coagulation under the conventional conditions and the subsequent washing is neutralized with a basic solution, followed by washing with a fluid capable of dissolving the basic solution, and then dried at a specific temperature set depending upon the residual moisture content in the fiber. The present invention further provides a polybenzazole intermediate predried fiber having a residual moisture content of about 25% and exhibiting a single peak for liquid freezing in the fiber over a temperature range of from 20.degree. to -70.degree. C. when measured by differential scanning calorimetry (DSC).

Processes for producing polybenzazole fibers

Growing community of inventors

Otsu, Japan

Tooru Kitagawa