Nippon Shokubai Co., Ltd.

Nippon Shokubai Kagaku Kogyo Co., Ltd.

Kawasaki Jukogyo Kabushiki Kaisha

Hitachi Metals, Ltd.

Nippon Shokubai

Nippon Shokubai Kagaku, Co., Ltd.

Hiroya Kobayashi

Hiroshi Itoh

Tadao Shimomura

Kazuhiro Okamura

Tsuneo Tsubakimoto

Koji Fukuhara

Yoshinobu Yamamoto

Yoshinori Sano

Tsuyoshi Hirata

Hiroshi Ito

Hideyuki Tahara

Takashi Namba

Teruki Matsushita

Masashi Yukitake

Futoshi Kuniyoshi

Kenji Minami

Toshio Tamura

Takakiyo Goto

Kenji Rakutani

Hayami Ito

Toshiaki Kuriyama

Shoichi Takao

Shuhei Tatsumi

Yoshiyuki Takahashi

Ryoichi Oshiumi

Yoshihiro Kajibata

Shuzo Fukuchi

Masahiro Shiroshima

Tetsuzo Hayashi

Akio Nakaishi

An R-T-B based sintered magnet includes both a light rare-earth element R(which is at least one of Nd and Pr) and a heavy rare-earth element R(which is at least one of Dy and Tb) and NdFeB type crystals as a main phase. The magnet has a first region, which includes either the heavy rare-earth element Rin a relatively low concentration or no heavy rare-earth elements Rat all, and a second region, which includes the heavy rare-earth element Rin a relatively high concentration. The first and second regions are combined together by going through a sintering process.

R-T-B sintered magnet and method for producing the same

The present invention provides: a production process for a polyalkylene oxide with fast polymerization reaction rate and good production efficiency; a catalyst for polymerization and a dispersion thereof which are effective for the above production process for a polymer such as polyalkylene oxide; and an organometallic fine particle and a production process therefor, which particle is, for example, useful as the above catalyst for polymerization. In a means therefor, a material such as an aliphatic polyol is reacted upon an organometallic compound in a micelle as the reaction field, thus preparing a hyperfine particle, which is used as a catalyst for polymerization of ionic-polymerizable monomers mainly including a cyclic ether.

Production process for organometallic fine particle and catalyst for

A film-formable high molecular polyetherpolyester comprising structural unit (1) of formula (1) and functional group (2) of formula (2) and having a number-average molecular weight of 40,000 to 10,000,000, wherein the molar ratio of functional group (2) to R in the polyetherpolyester is in the range of 1.0 to 3.0. This polyetherpolyester can be produced by carrying out a chain extension reaction of a low molecular polyalkylene oxide of 1,000 to 30,000 in number-average molecular weight with a polyvalent acid anhydride at 0.003 MPa or higher in a molar ratio of (acid anhydride group)/(hydroxyl group)=0.8 to 1.0. ##STR1##

High molecular polyetherpolyester and its production process and use

A polyester resin composition comprises: an aliphatic polyester having a number-average molecular weight (Mn) in a range of 10,000 to 100,000; and a crystalline nucleating agent, wherein the aliphatic polyester and the crystalline nucleating agent are mixed in such that a half value width of an exothermic peak based on an annealing crystallization of the aliphatic polyester measured by differential scanning calorimetry in an atmosphere of nitrogen at a cooling rate of 3K/minute is not more than 15K. This polyester resin composition has a biodegradability and a high crystallization rate. The polyester resin composition also has excellent mechanical properties and eliminates a precise temperature control during a molding process which saves labor force resulting in desirable moldability and productivity. For the described beneficial properties, the polyester resin composition can be readily processed into a fiber, a molded article, sheet, film and the like. Accordingly, a film made of the polyester resin composition can be effectively used for disposable packing materials, miscellaneous goods for daily use, and the like.

Polyester resin composition

A process for producing a high-molecular-weight polydioxolane, which includes the steps of: polymerizing 1,3-dioxolane using a polymerization catalyst comprising a heteropolyacid and a ketone; and neutralizing the resulting polymerization reaction product using an organic amine and/or ammonia. A hydrophilic film, which includes a resin including a polydioxolane and having a particular molecular weight and has a particular crystallinity and a particular spherulite's size. A film crumbly in cold water is produced by forming a film under particular forming conditions from a resin including a polydioxolane and having a particular molecular weight, or by subjecting an already formed film to particular thermal hysteresis.

Production process for making high molecular weight polydioxolane

A method for producing an aliphatic polyester having a biodegradability and a higher melting point than conventional aliphatic polyester by suppressing a volatile component generated by side reaction or decomposition reaction with industrially good efficiency and economically in a relatively short period of time, the method enabling a polymerization at vacuum which permits a use of general vacuum pump. The aliphatic polyester can be obtained, for example, by a ring-opening copolymerization of a cyclic acid anhydride with a cyclic ether in a presence of a zirconium compound. The aliphatic polyester also can be obtained by performing a polymerization of raw materials of the aliphatic polyester so as to have a degree of viscosity in the range of 10-10,000 poise when 0.1-30 hours elapsed after the reaction started at reaction temperature of the reaction system under conditions of reaction temperature in the range of 180.degree. C. to 280.degree. C. and reaction pressure in the range of 0.3 mmHg to 3.0 mmHg.

Process for producing aliphatic polyester

This invention provides a process for producing with industrially good efficiency a polyester having a high melting point and biodegradability. In this process, ring-opening copolymerization of a cyclic acid anhydride containing succinic anhydride as a main component with a cyclic ether containing ethylene oxide as a main component is carried out in the presence of a catalyst by introducing successively the cyclic ether into a reaction vessel containing the cyclic acid anhydride in a melting state or solution state. The rate per hour of introducing the cyclic ether is within the range of 3 to 90 parts by weight per 100 parts by weight of the cyclic acid anhydride, and the reaction vessel has an inside pressure within the range of atmospheric pressure to 50 kgf/cm.sup.2 as a gauge pressure.

Process for producing polyester by ring-opening copolymerization

A waterproofing agent for an optical or electric cable, formed of a cross-linked macromolecular compound containing a sulfonic acid group or a salt thereof in an amount of not less than 0.5 mg. equivalent/g and a dissociating group in an amount of not less than 1.0 mg. equivalent/g, and a method for waterproofing said cable by packing said waterproofing agent in the sheath of said cables.

Method for waterproofing with a cross-linked macromolecular

A cable grade water proofing agent made of a cross-linked polymer produced by polymerizing a monomer mixture comprising at least one (meth)acrylic compound selected from the group consisting of (meth)acrylic acids and (meth)acrylic salts and a (meth)acrylamide in a molar ratio of said (meth)acrylic compound to said (meth)acrylamide in the range of from 1:9 to 5:5, said cross-linked polymer exhibiting a speed of absorption of not more than 8 minutes as expressed by the time required for the absorption of artificial seawater to reach 90% of the maximum, a capacity for absorption of said artificial seawater of not less than 8 times the own weight, and a gel viscosity in the range of from 0.6.times.10.sup.5 to 2.5.times.10.sup.5 dynes.multidot.s/cm.sup.3, and a composite waterproofing material carried on a substrate such as yarns and tape.

Waterproofing agent for cable

Waterproofing tape comprising ethylenic sulfonate polymers

A cement dispersant having as a main component thereof at least one polymer selected from the group consisting of polymers obtained from (A) 0.1 to 100 mol % of a sulfonic acid type monomer represented by the formula I: ##STR1## wherein R stands for hydrogen atom or methyl group, X stands for hydrogen atom, a monovalent metallic atom, a divalent metallic atom, ammonium group, or an organic amine group, A and B independently stand for an alkylene group of 2 to 4 carbon atoms, m stands for 0 or an integer of the value of 1 to 100, and the alkylene oxide group of 2 to 4 carbon atoms in the portion, (AO).sub.m may be bound in any desired sequence, and (B) 99.9 to 0 mol % of olther monomer copolymerizable with said sulfonic acid type monomer, and polymers obtained by neutralizing said polymers with an alkaline substance, a cement composition containing the dispersant and a method for dispersing a cement.

Cement with sulfoalkyacrylate polymers

Dispersant for aqueous slurry of carbonaceous solid and aqueous

A cement dispersant having as a main component thereof at least one polymer selected from the group consisting of polymers obtained from (A) 0.1 to 100 mol % of a sulfonic acid type monomer represented by the formula I: ##STR1## wherein R stands for hydrogen atom or methyl group, X stands for hydrogen atom, a monovalent metallic atom, a divalent metallic atom, ammonium group, or an organic amine group, A and B independently stand for an alkylene group of 2 to 4 carbon atoms, m stands for 0 or an integer of the value of 1 to 100, and the alkylene oxide group of 2 to 4 carbon atoms in the portion, (AO).sub.m may be bound in any desired sequence, and (B) 99.9 to 0 mol % of other monomer copolymerizable with said sulfonic acid type monomer, and polymers obtained by neutralizing said polymers with an alkaline substance, a cement composition containing the dispersant and a method for dispersing a cement.

Cement dispersant

A composite semipermeable membrane comprising a porous support and a crosslinked thin film formed on said porous support, said crosslinked thin film being formed by reacting compound (A) which is at least one compound selected from the group consisting of polyalkylenimines and polyalkylenimine derivatives, compound (B) which is at least one compound selected from a group of compounds typified by piperazine, 2,5-dimethylpiperazine, 4-aminomethylpiperidine and 1,4,8,11-tetraazacyclotetradecane, and compound (C) as a crosslinking agent which is a compound having in one molecule two or more functional groups capable of reacting with amino groups; and a process for preparing said composite semipermeable membrane.

Crosslinked composite semipermeable membrane

Growing community of inventors

Minoo, Japan

Hiroya Kobayashi