Bridgestone Corporation

Bridgestone Tire Company Limited

Toray Industries, Inc.

Kawasaki Steel Corporation

Other

Sumitomo Metal Industries, Inc.

Tasuku Saito

Yuichi Ishino

Takayuki Maruyama

Shigeki Endo

Tsutomu Matsunaga

Yasuo Kurachi

Chiaki Tanaka

Nagayoshi Naito

Yoshiki Fukuyama

Hiroaki Wada

Ryo Sakurai

Tutomu Noma

Shinichi Kakiuchi

Seisuke Tomita

Masashi Otsuki

Yoshitomo Takahashi

Motoki Hiratsuka

Yoko Furuta

Toshiyuki Osaki

Mitsuya Tanaka

Hitomi Hatano

Takashi Haraoka

Kazuo Naito

Takao Ogino

Hidefumi Kotsubo

Minoru Ishiharada

Kenji Fukuda

Tatsuo Umeno

Katsuhiro Nagayama

Youichiro Hara

Sakae Inoue

Haruyuki Kano

Nobuyuki Kataoka

Ryota Kajita

Ryou Sakurai

Kazuhiro Minagawa

Masayuki Ohtake

Tomoko Noguchi

Shoichi Kojima

Noriyoshi Fukuda

Kaori Takagi

Tasuo Kurachi

Koji Sakata

Takayuki Torii

Howard See

Osaki Toshiyuki

The present invention can provide particles for electro-rheological fluid for providing a high electro-rheological effect over a wide temperature range at low electric power consumption, and having high strength and excellent durability, not being susceptible to break-up due to the load of stress. Particles for an electro-rheological fluid of the present invention comprise spherical carbonaceous particles, obtained substantially from a solvent and a condensation product of a methylene type bond of aromatic sulfonic acid or a salt thereof.

Particles for electro-rheological fluid

An electro-rheological fluid made from an oil medium and fine particulates by mixing, is highly reliable and in which dielectric breakdown, such as generation of electrical discharge, is very low even when a high voltage is applied. A method of manufacturing the electro-rheological fluid and a method of storing the fluid are also provided. The electro-rheolological fluid includes fine particulates dispersed in an oil medium having an electric insulation property, and has a dielectric breakdown strength of 4 kV/mm or more. When the electro-rheological fluid is placed under a reduced pressure of 10 Pa, foaming does not occur. Alternatively, the electro-reheoleological fluid can contain 20% by volume or more of a gas contained in the oil medium that has a dielectric breakdown strength of 4 kV/mm or more.

Electro-rheological fluid having high dielectric breakdown stength and methods of making and storing the electro-rheological fluid

A sintered silicon carbide containing nitrogen is obtained by sintering a mixture of a powder of silicon carbide and a nonmetallic auxiliary sintering agent. The sintered silicon carbide has a density of 2.9 g/cm,or more and contains 150 ppm or more of nitrogen. The sintered silicon carbide preferably has a volume resistivity of 1 &OHgr;&middot;cm or less and contains &bgr;-silicon carbide in an amount of 70% or more of total silicon carbide components. Nitrogen can be introduced into the sintered silicon carbide by adding a nitrogen source, for example, an amine such as hexamethylenetetramine, ammonia, and triethylamine in the production of the powder of silicon carbide which is used as the material powder for producing the sintered silicon carbide or by adding the nitrogen source in combination with the nonmetallic auxiliary sintering agent in the production of the sintered silicon carbide. A high quality sintered silicon carbide having a high density, exhibiting both electric conductivity and high heat conductivity, which can be advantageously used in various fields such as semiconductor industry and electronic information processing instruments industry, is provided.

Method for producing sintered silicon carbide

A sintered silicon carbide containing nitrogen is obtained by sintering a mixture of a powder of silicon carbide and a nonmetallic auxiliary sintering agent. The sintered silicon carbide has a density of 2.9 g/cm.sup.3 or more and contains 150 ppm or more of nitrogen. The sintered silicon carbide preferably has a volume resistivity of 1 .OMEGA..multidot.cm or less and contains .beta.-silicon carbide in an amount of 70% or more of total silicon carbide components. Nitrogen can be introduced into the sintered silicon carbide by adding a nitrogen source, for example, an amine such as hexamethylenetetramine, ammonia, and triethylamine in the production of the powder of silicon carbide which is used as the material powder for producing the sintered silicon carbide or by adding the nitrogen source in combination with the nonmetallic auxiliary sintering agent in the production of the sintered silicon carbide. A high quality sintered silicon carbide having a high density, exhibiting both electric conductivity and high heat conductivity, which can be advantageously used in various fields such as semiconductor industry and electronic information processing instruments industry, is provided.

Sintered silicon carbide and method for producing the same

The present invention relates to an anisotropically electricity-conductive film obtainable by dispersing in an adhesive agent electrically conductive particles, the adhesive agent being a curable adhesive agent comprising as a major component at least one polymer selected from the group consisting of an ethylene-vinyl acetate copolymer; a copolymer of ethylene, vinyl acetate and an acrylate and/or methacrylate monomer; a copolymer of ethylene, vinyl acetate and maleic acid and/or maleic anhydride; a copolymer of ethylene, an acrylate and/or methacrylate monomer and maleic acid and/or maleic anhydride; and an ionomer resin wherein molecules of an ethylene-methacrylic acid copolymer are linked with each other through a metal ion.

Anisotropically electricity conductive film comprising thermosetting

An electrorheological fluid is constituted by using a dispersed phase of a carbonaceous powder having an oxygen content above 10% by weight but not more than 20% by weight and having an average particle diameter of 0.01-100 .mu.m, obtained by: heat-polymerizing a condensed polycyclic aromatic compound containing a main component of naphthalene by using HF/BF.sub.3 as a catalyst to obtain a 100% meso-phase pitch having a softening point within a range of 150.degree.-400.degree. C.; heat-treating and making the pitch infusible in an oxidizing atmosphere at a temperature not more than a fusing temperature of the pitch and not less than 50.degree. C. but not more than 400.degree. C. to allow the pitch to have an oxygen content of 12-25% by weight; and then heat-treating and carbonizing the pitch in an inert gas atmosphere at a temperature not less than 300.degree. C. but not more than 700.degree. C. It is thus possible to obtain an electrorheological fluid having low current consumption, a high electrorheological effect and excellent long-term durability, even when the carbonaceous powder having high oxidation resistance and a high oxygen content is used.

Carbonaceous powder to be dispersed in electrorheological fluid and

A process for producing a powder material for an electro-rheological fluid is provided. The powder material is advantageously used for an electro-rheological fluid having a property, such as viscosity, which changes by application of an electric field. A powder material for an electro-rheological fluid having a uniform distribution of particle diameters and a uniform distribution of electric conductivity can be produced by embrittling a carbonaceous powder material, pulverizing and classifying the embrittled carbonaceous powder material to obtain a carbonaceous powder material having a uniform distribution of particle diameters, and carbonizing the powder material under an atmosphere of an inert gas.

Process for producing a powder material for an electro-rheological fluid

In an optical waveguide comprising a transparent cladding (1) filled with a transparent liquid core (2) having a higher refractive index than the cladding, a liquid consisting of an oligomer having a phosphazene skeleton, typically phosphazene oil is used as the core (2). The waveguide is well resistant to heat and weathering, ensures stable performance in a wide temperature range over a long period of time, and provides good light transmission in a wide wavelength range covering the UV, visible and IR spectra.

Optical waveguide

The present invention relates to an electrorheological semisolid capable of changing the rheological characteristics by an application of voltage. The semisolid is composed of 20-70 weight. Parts of carbonaceous particulates having an average particle size of 0.1-500 .mu.m and a carbon/hydrogen atomic ratio (C/H ratio) of 1.2-5 which are dispersed in 80-30 weight % of a dispersion medium comprising a partially crosslinked electric insulating polymer having a penetration of 40-475 at 25.degree. C., or into 80-30 weight % of a dispersion medium selected from an electric insulating oil having a viscosity of 5000 to 10.sup.9 centistokes at 25.degree. C. and an electric insulating polymer having a viscosity of 5000 to 10.sup.9 centistokes at 25.degree. C.

Electrorheological semisolid

A method for producing a carbonaceous powder which can be used as dielectric fine particles to be dispersed in an insulating oil to produce an electrorheological fluid is provided. The method comprises the steps of subjecting a starting organic material selected from the group consisting of coal, coal tar, coal tar pitch, liquefied coal, coke, petroleum, petroleum tar, petroleum pitch, and resins to a heat treatment at a maximum temperature of 300.degree. to 800.degree. C. to produce carbonaceous material; pulverizing and classifying the material to produce carbonaceous particles having a mean particle size of 0.5 to 40 .mu.m and a maximum particle size of up to 50 .mu.m; and subjecting the particles to an additional treatment at an elevated temperature and/or a reduced pressure, said additional treatment being carried out at a temperature lower than said maximum temperature of the heat treatment. The resulting carbonaceous powder may optionally be subjected to a further pulverization treatment.

Method for producing carbonaceous powder for electrorheological fluid

A process for the preparation of a beta-silicon carbide powder of high purity which is suitable for use in the manufacture of semiconductor equipment and which has a content of 1 ppm or less of each atom harmful to the manufacture of semiconductor devices. The process comprises preparing a carbon- and silicon-containing starting mixture comprising (a) at least one siliceous material selected from liquid silicon compounds and solid siliceous substances derived from a hydrolyzable silicon compound, and (b) at least one carbonaceous material selected from polymerizable or cross-linkable organic compounds prepared in the presence of a catalyst which is substantially free from atoms harmful to the manufacture of semiconductor devices. The starting mixture comprises at least one liquid substance used as component (a) or (b). The starting mixture is then solidified by heating and/or by use of a catalyst or a curing agent. The resulting solid body is optionally heat treated in a non-oxidizing atmosphere at a temperature in the range of from 500.degree. C. to 1300.degree. C. for a period sufficient to remove volatiles. The cured and optionally heat-treated body is calcined in a non-oxidizing atmosphere under conditions sufficient to give beta-silicon carbide powder.

Process for preparing silicon carbide powder for use in semiconductor

An electro-responsive elastomeric material comprising (A) an electrically insulating polymer having a specific modulus of elasticity and (B) a fine powder dispersed in the polymer which electrically polarizes under an electric field independent of water changes its viscoelasticity upon voltage application. The powder has a mean particle size of 0.5 to 500 .mu.m and is (1) a fine carbonaceous powder having a C/H atomic ratio of from 1.2 to 5, (2) composite particles having minute particulates of an insulating material dispersed in a matrix phase of a carbonaceous or carbide material, (3) composite particles having minute particulates of a carbonaceous or carbide material dispersed in a matrix phase of an insulating material, or (4) a fine composite powder of a stratum clay mineral having a two-dimensional stratum structure with a carbonaceous or carbide material incorporated between the strata.

Electro-responsive elastomeric material

A positive electrode and a negative electrode are disposed in face-to-face relation to allow a distance between the electrodes to change, and an electrorheological fluid is filled between the electrodes. When an external force is applied to the electrorheological fluid via the electrodes, a normal stress occurs in the electrorheological fluid. This normal stress is greater than a shearing stress occurring in the electrorheological fluid, and an area in which displacement is proportional to the stress is large. Hence, the electrorheological fluid is applicable to various apparatuses such as a vibration controller and a fixing apparatus.

Electrorheological fluid-applied apparatus, electrorheological

The present invention relates to an electrorheological fluid which is capable of increasing viscosity under an application of electric potential difference. An electrorheological fluid according to the present invention comprises dielectric particulates dispersed in a highly electrically insulating oily medium, in which the particulates are carbonaceous particulates having an atomic ratio of carbon atoms to hydrogen atoms (C/H) of 1.70-3.50 and an average particle size of from 0.01 to 100 .mu.m, and the oily medium is an electrical insulating oil having a dielectric constant of not less than 3 and a volume resistivity of not less than 10.sup.9 .OMEGA..multidot.cm.

Electrorheological fluids comprising dielectric particulates dispersed

A powder having improved oxidation resistance and controlled electrical properties is obtained by dispersing minute particulates in a matrix phase to form composite particles. The minute particulates may be distributed uniformly or non-uniformly such that the particulates are dense near the surface and sparse near the center of each particle or inversely. The matrix phase has a moderate conductivity of 10.sup.-10 to 10.sup.2 Scm.sup.-1, and the dispersed particulates have a low conductivity of up to 1/10 of that of the matrix phase, typically up to 10.sup.-2 Scm.sup.-1. Alternatively, the matrix phase has a lower conductivity and the dispersed particulates have a moderate conductivity. The powder is dispersed in an insulating oily medium to form an electrorheological fluid.

Powder and electrorheological fluid

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Tokorozawa, Japan

Tasuku Saito