Denki Kagaku Kogyo Kabushiki Kaisha

Denka Company Limited

Fuji Electric Co., Ltd.

Toyoda Gosei Co., Ltd.

Nagaoka University of Technology

Yasushi Abe

Uichiro Yamagishi

Naoki Kobayashi

Toshiaki Miyauchi

Takashi Sunada

Shogo Hagiwara

Hiroyuki Ishiguro

Motoyoshi Kubouchi

Masao Koga

Takashi Kawasaki

Masayoshi Ichikawa

Kiyoshi Takahashi

Tomoaki Okita

Yoshinobu Isono

Kazuomi Aoki

Takeo Kondo

Yuichiro Kushida

Mitsuyuki Nakada

Motohiro Ose

Makoto Hashii

Yasuhiro Kanba

Hideki Toya

Isao Yamagishi

Satoru Ikari

Naoki Kabayashi

Hiroaki Shimizu

Ryochi Suzuki

A rubber composition from which a vulcanized rubber simultaneously improved in three characteristics of oil resistance, cold resistance and ozone resistance can be obtained, and a molded article using the vulcanized rubber are provided. The rubber composition contains 50 to 99 parts by mass of a chloroprene rubber containing 0.01 to 20% by mass of an unsaturated nitrile monomer unit and 1 to 50 parts by mass of a non-conjugated diene rubber.

Rubber composition, vulcanized rubber, and molded article of said vulcanized rubber

A rubber-based composition modifier includes 100 parts by mass of a mixed rubber component containing a chloroprene rubber and at least one copolymer selected from ethylene/&#x3b1;-olefin copolymers and ethylene/&#x3b1;-olefin/unconjugated polyene copolymers, 10 to 60 parts by mass of magnesium oxide, 3 to 30 parts by mass of a softener, and 30 to 120 parts by mass of acetylene black, wherein the mixed rubber component has a Mooney viscosity, as determined by the method specified in JIS K6300, of 60 to 180 at 100&#xb0; C.; the magnesium oxide has a BET specific surface area, as determined by the one point method specified in JIS Z8830, of 20 to 150 m/g; the softener contains a fatty acid ester-based plasticizer and an unsaturated fatty acid having a carbon number of 10 to 24 and containing an ester bond, a hydroxyl group, or both of them in part of the structure.

Rubber-based composition modifier, and vulcanizate and molded product of rubber composition containing the rubber-based composition modifier

In a three-level chopper apparatus, a protection switch circuit is controllable to change a current pathway through which an overvoltage is applied to a second capacitor or a first capacitor to a current pathway through which no overvoltage is applied to the second capacitor or the first capacitor.

Three-level chopper apparatus

A three-level chopper apparatus includes a protection switch circuit that changes a current pathway through which an overvoltage is applied to a second capacitor or a first capacitor to a current pathway through which no overvoltage is applied to the second capacitor or the first capacitor when a first switch or a second switch has a failure.

The invention provides compositions of chloroprene rubbers having improved vibration-damping properties under low temperature conditions without deterioration of mechanical properties, permanent compression set and tension fatigue in the final product. The chloroprene rubbers of the invention contain a xanthogen-modified chloroprene rubber and/or a mercaptan-modified chloroprene rubber in an amount of 100 parts by mass, a carbon black having an average particle diameter of 70 mn to 600 mn and a DBP oil absorption (as determined by Absorption A method of JIS-K6221) of 15 ml/100 g in an amount of 15 to 150 parts by mass, and a plasticizer represented by the chemical formula RCOO&#x2014;(CH)&#x2014;COORwherein Rand Reach represent an alkyl group having 1 to 7 carbons.

Chloroprene rubber composition and vulcanized rubber thereof, and rubber molded product, vibration-damping rubber member, engine mount, and hose using vulcanized rubber

Provided are a rubber composition that gives a vulcanizate superior in heat resistance and a vulcanizate and a molded article thereof. A rubber composition, comprising a rubber component consisting of a chloroprene rubber: 50 to 90 mass % and an elastomer: 10 to 50 mass % in a total amount of 100 parts by mass, a zinc powder having an arithmetic mean particle diameter, as determined by the method specified by JIS Z8901, of 3 to 10 &#x3bc;m in an amount of 3 to 20 parts by mass, and a magnesium oxide having a BET specific surface area, as determined by the one-point method specified by JIS Z8830, of 20 to 150 m/g in an amount of 4 to 16 parts by mass. A vulcanizate and a molded article obtained by molding and vulcanization of the rubber composition.

Rubber composition, and vulcanizate and molded article thereof

To provide a chloroprene rubber composition providing good permanent compression set and excellent mechanical strength, a vulcanizate of the composition, and a molded article of the composition. A chloroprene rubber composition including a chloroprene rubber and a natural rubber in a total amount of 100 parts by mass, a copolymer of styrene and butadiene in an amount of 0.1 to 10 parts by mass, ethylene thiourea in an amount of 0.1 to 3.0 parts by mass, and dipentamethylenethiuram tetrasulfide in an amount of 0.1 to 3.0 parts by mass is vulcanized after or during molding of the composition to yield a vulcanized molding.

Chloroprene rubber composition, and vulcanizate and molding thereof

A single phase three-level power converter can include a first half bridge and a second half bridge. A half bridge operation is implemented in either the first half bridge or second half bridge when outputting a single phase alternating current voltage having an amplitude a half or less than that of a direct current input voltage, and also, by alternately switching between the bridges carrying out the half bridge operation. In certain configurations, the power converter can convert a direct current input voltage into alternating current phase voltages having three levels of potential, which are positive, negative, and intermediate voltages, by controlling on-off conditions of a plurality of switch elements, and a controller that, by supplying gate signals to the switch elements configuring the first half bridge and second half bridge, controls the related on-off conditions.

Power conversion device

Provided are a blended rubber and a blended rubber composition that give a vulcanizate superior in abrasion resistance and ozone resistance, and a vulcanizate prepared by vulcanizing the blended rubber composition. A blended rubber, comprising 30 to 93 mass % of a chloroprene rubber, 5 to 50 mass % of a soft polyvinyl chloride, and 2 to 20 mass % of an acrylonitrile-butadiene rubber. The polyvinyl chloride resin used preferably has a polymerization degree of 300 to 3000 and the acrylonitrile-butadiene rubber preferably has an acrylonitrile content of 18 to 50 mass %.

Blended rubber, blended rubber composition and vulcanizate

An object of the invention is to provide a sulfur-modified chloroprene rubber composition improved in heat resistance. A sulfur-modified chloroprene rubber composition, comprising a sulfur-modified chloroprene rubber containing sulfur chemically bound thereto and sulfur not chemically bound to the sulfur-modified chloroprene rubber, wherein: the ratio of the amount of sulfur chemically bound to the sulfur-modified chloroprene rubber to the total amount of sulfur in the sulfur-modified chloroprene rubber composition (amount of chemically bound sulfur [mass %]/total amount of sulfur [mass %]) is 0.1 to 0.45; and the sulfur-modified chloroprene rubber has, at the molecular terminal, at least one structure represented by the following General Formula (1) or (2): &#x2014;S&#x2014;C(&#x2550;S)&#x2014;O&#x2014;R. . . (1) (in General Formula (1), Rrepresents an alkyl group having 1 to 4 carbon atoms) or &#x2014;S&#x2014;R. . . (2) (in General Formula (2), Rrepresents an alkyl group having 8 to 20 carbon atoms).

Sulfur-modified chloroprene rubber composition and molded body

Provided are a sulfur-modified chloroprene rubber with reduced exothermicity, a molding thereof, and a production method therefor. A sulfur-modified chloroprene rubber modified at the polymer terminals with at least one compound selected from tetramethylthiuram disulfide, tetraalkylthiuram disulfides with alkyl groups having a carbon number of 2 to 7 and dialkyldithiocarbamic acid salts with alkyl groups having a carbon number of 1 to 7, wherein there are peak tops at 3.55 to 3.61 ppm and at 3.41 to 3.47 ppm inH-NMR spectrum, as determined in deuterochloroform solvent, wherein the ratio (A/B) of the peak area (A) at 3.55 to 3.61 ppm to the peak area (B) at 4.2 to 6.5 ppm is 0.05/100 to 0.50/100, and the extract with ethanol/toluene azeotropic mixture, as specified by JIS K 6229, is 3.0 to 9.0 mass %.

Sulfur-modified chloroprene rubber, molding thereof, and production method therefore

Provided is a laminate having elastomer layers tightly bonded to each other. The laminate according to the present inventionhas an acrylic elastomer layerand a fluorine elastomer layerthat are bonded to each other. The acrylic elastomer layeris made of an acrylic elastomer composition having an epoxy group-containing acrylic elastomer and an onium salt added and the fluorine elastomer layeris made of a fluorine elastomer composition having a fluorine elastomer and a polyol crosslinking agent added. In the laminate, the elastomer layers are bonded tightly to each other even without any surface treatment.

Laminated body and vulcanizate therefor

Provided are a vulcanizate of a chloroprene rubber composition containing carbon black that generates a smaller amount of heat when used and a method for producing the same by a simpler and more convenient method. First, an unvulcanized rubber composition at least containing a chloroprene polymer and carbon black is vulcanization-molded, to give a semivulcanized molded article having a cure characteristic value, as determined by the method specified in JIS K6300-2: 2001, in the range of tto t. Then, the semivulcanized molded article obtained by semivulcanized film-forming step is additionally vulcanized in the state as it is deformed entirely and the deformation is removed, to give vulcanizate in a desired shape.

Vulcanizate and process for producing same

This invention provides a means to produce improved sulfur-modified chloroprene rubber for use in making products with improved heat resistance. The products of the invention require sulfurization of the chloroprene followed by plasticization. A preferred plasticizer is tetraethylthiuram.

Sulfur-modified chloroprene rubber, molded article, and method for producing sulfur-modified chloroprene rubber

To provide an acrylic rubber composition and its vulcanized product, having excellent workability and an excellent balance of the vulcanization properties, the reduction of scorching, the rubber mechanical properties, the compression set and the heat resistance. An acrylic rubber composition comprising a carboxy group-containing acrylic rubber, a novolac phenol resin salt of a diazabicycloalkene compound and a polyamine compound. Particularly, the diazabicycloalkene compound is preferably 2,3,4,6,7,8,9,10-octahydropyrimido(1,2-a)azepine or 2,3,4,6,7,8-hexahydropyrrolo(1,2-a)pyrimidine, and the polyamine compound is preferably an aromatic polyamine or an aliphatic polyamine.

Growing community of inventors

Itoigawa, Japan

Yasushi Abe