Shin-etsu Chemical Co., Ltd.

Other

Zeon Corporation

Kazuhiro Oishi

Yoshiaki Koike

Osamu Hayashida

Atsuhito Kashima

Masakatsu Hotta

Toshio Yamazaki

Seiki Chiba

Mikio Waki

Takao Uno

Tatsuei Hara

Provided are a high dielectric insulating silicone rubber composition and an electric field relaxation layer. This high dielectric and insulating silicone rubber comprises: (A) 100 parts by mass of an organopolysiloxane represented by formula (1),RSiO&#x2003;&#x2003;(1),(in the formula, Rrepresents the same or different, substituted or unsubstituted monovalent hydrocarbon groups, and n is a positive number of 1.95 to 2.04); (B) 60 to 150 parts by mass of thermal black having an average primary particle size of 150 to 500 nm; (C) 5 to 100 parts by mass of reinforcing fumed silica having a specific surface area measured by a BET adsorption method of 50 m/g or more; and (D) 0.1 to 10 parts by mass of a curing agent. The composition is characterized in that a cured product thereof satisfies a dielectric constant of 10 or more, a volume resistivity of 1.0&#xd7;10to 1.0&#xd7;10&#x3a9;&#xb7;cm, a loss tangent of 0.1 or less, and a dielectric breakdown strength (BDV) of 7 kV/mm or more.

High dielectric insulating silicone rubber composition and electric field relaxation layer

Provided are a self-welding high dielectric silicone rubber composition and a self-welding high dielectric tape. The self-welding high dielectric silicone rubber composition comprises: (A) 100 parts by mass of an organopolysiloxane represented by an average composition formula (1) and having, in a molecule, at least two alkenyl groups bonded to silicon atoms, RSiO(1), (in the formula, Rrepresents the same or different, unsubstituted or substituted monovalent hydrocarbon group and n is a positive number of 1.95 to 2.04); (B) 10 to 100 parts by mass of hydrophobic fumed silica having a specific surface area obtained by the BET adsorption method of 50 m/g or larger; (C) 100 to 300 parts by mass of a conductive complex oxide; (D) 0.1 to 50 parts by mass of a boric acid or a boric acid compound; (E) 1 to 10 parts by mass of a diorganopolysiloxane capped at both molecular terminals with alkoxy groups; and (F) 0.01 to 10 parts by mass of a curing agent comprising an acyl organic peroxide. The self-welding high dielectric silicone rubber composition can be hot-air vulcanized under normal pressure by extrusion molding or roll forming with calender rolls.

Self-welding high dielectric silicone rubber composition and self-welding high dielectric tape

A method is provided for manufacturing a dielectric elastomer transducer including a dielectric elastomer layer and electrode layers sandwiching the elastomer layer. The elastomer layer when stretched exhibits a stress-strain curve having: a low strain and high elasticity region; a low elasticity region; and a high strain region. The method includes: a pre-stretching process to reduce hysteresis in elastic behavior of the elastomer layer by stretching the elastomer layer one or more times under a load as heavy as a first load before the electrodes are provided, each stretching causing the elastomer layer to undergo a tension falling in the low elasticity region; and a dielectric elastomer layer fixing process including applying a second load smaller than the first load to the elastomer layer so as to fix the elastomer layer to a support member under a second tension smaller than the first tension.

Method for manufacturing dielectric elastomer transducer

The present invention provides a millable silicone rubber composition characterized by comprising: (A) two raw alkenylated organopolysiloxane rubbers (A-1) and (A-2), i.e., a raw organopolysiloxane rubber including a molecular chain which is represented by a specific empirical formula and in which each of both terminals has been blocked with a trialkenylsiloxy group and a raw organopolysiloxane rubber including a molecular chain which is represented by a specific empirical formula and in which each of both terminals has been blocked with a monoalkenyldialkylsiloxy group; (B) an organohydrogenpolysiloxane having at least two silicon-atom-bonded hydrogen atoms in the molecule; (C) carbon black having an average primary-particle diameter of 100-350 nm; (D) reinforcing fumed silica having a specific surface area, as determined by the BET adsorption method, of 50 m/g or greater; and (E) a platinum-group metal catalyst. This millable silicone rubber composition has an excellent electric-field relaxation ability, a high elongation at break, a reduced tension set, and high dielectric or insulating properties.

Millable silicone rubber composition and electric-field relaxation layer

The present invention provides a silicone composition comprising components (A) to (F); (A) 100 parts by mass of a raw rubber-like, at 25 degrees C., organopolysiloxane having at least two alkenyl groups each bonded to a silicon atom; (B) 5 to 100 parts by mass of silica powder having a specific surface area of 50 m/g or more; (C) platinum or a platinum compound in an amount of 1 to 1,000 ppm by mass as a platinum atom, relative to the mass of component (A); (D) 0.01 to 5 parts by mass of a compound selected from an organic silicon compound having a nitrogen-containing organic group and an unsaturated hydrocarbon group, and benzotriazole and a derivative thereof; (E) an addition reaction curing agent other than said component (C), or an organic peroxide in an effective amount to cure the composition, and (F) 0.01 to 5 parts by mass of an aromatic hydrocarbon group-containing organopolysiloxane represented by the general formula (1) wherein a proportion of the number of the monovalent aromatic hydrocarbon group to the total number of the substituents R, Rand Ris 41% or more and less than 46%.

Silicone composition, a cured silicone rubber product and a power cable

Disclosed herein are a silicone rubber composition and a power cable. The silicone rubber composition has excellent insulation properties and a high permittivity and which can further become a silicone dielectric material having a low specific gravity and a high strength. The power cable in which a terminal connection part or an intermediate connection part is composed of a cured molded product of the just-mentioned composition. The silicone rubber composition includes (A) 100 parts by weight of an organopolysiloxane containing at least two Si-bonded alkenyl groups in one molecule thereof, (B) 5 to 50 parts by weight of a reinforcing silica having a specific surface area measured by a BET method of 50 m/g to 400 m/g, (C) 0.3 to 3 parts by weight of carbon nanotubes having an average diameter of 0.5 nm to 50 nm, and (D) a curing agent in an amount necessary for curing of the composition. A cured molded product of the composition has a volume resistivity of at least 10&#x3a9;&#xb7;cm and a relative permittivity of at least 5.

Silicone rubber composition and power cable

A fluorosilicone rubber composition is provided comprising (A) a fluorosilicone gum having an aliphatic unsaturated monovalent hydrocarbon group content of 0.03-1 mol % based on the total of monovalent hydrocarbon groups and a residual alkali metal content of up to 20 ppm, (B) reinforcing silica having a specific surface area of 50-100 m/g, and (C) an organic peroxide catalyst. The composition is molded into silicone rubber parts which are improved in compression set even after immersion in &#x3b5;-caprolactam.

Fluorosilicone rubber composition

A fluorosilicone rubber composition comprising (A) an alkenyl-rich fluorosilicone gum, (B) an alkenyl-poor fluorosilicone gum, (C) reinforcing silica, and (D) a curing catalyst cures into a product which experiences little change of physical strength even after immersion in alcohol-containing fuel oil.

A triorganosiloxy end-capped organopolysiloxane, i.e., organopolysiloxane having a backbone consisting essentially of repeating (3,3,3-trifluoropropyl)methylsiloxane units and end-capped with triorganosiloxy groups is prepared by copolymerizing tris(3,3,3-trifluoropropyl)trimethylcyclo-trisiloxane with a silanol end-capped organopolysiloxane in the presence of an alkyllithium or lithium silanolate catalyst to form a silanol end-capped copolymer, and adding a trialkylsilyl triflate or strong acid in excess relative to the catalyst and a hexaorganodisilazane for effecting end-capping and neutralization.

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Annaka, Japan

Kazuhiro Oishi