Nok Corporation

Freudenberg-nok General Partnership

Kenichi Fujimoto

Yoshifumi Kojima

Atsushi Koga

Kazuhisa Senda

Toshihiro Higashira

Hiroyuki Sano

Takeshi Sato

Nobuyuki Oka

Masayuki Kishimoto

Kenji Mikuni

Atsushi Nagashima

Shunji Ueda

Nobuyuki Shintaku

Kazuhiko Fujimoto

Yukihisa Tateishi

Hiromitsu Yamoto

Tamotsu Oi

Yasuaki Inuzuka

Disclosed is a fluororubber composition comprising (A) 100 parts by weight of a peroxide-crosslinkable fluororubber, (B) 1 to 15 parts by weight of ZnO, (C) at least one of a basic metal hydroxide and a metal oxide other than ZnO at a weight ratio of 0.5 or more with respect to the weight of ZnO, and (D) 0.5 to 10 parts by weight of an organic peroxide. When used for contact with biodiesel fuel, the peroxide-crosslinkable fluororubber composition effectively prevents material degradation shown in BDF while maintaining excellent compression set characteristics due to the addition of ZnO, as in conventional peroxide-crosslinkable fluororubbers, and therefore can be suitably used as, for example, a vulcanization molding material for sealing materials.

Fluororubber composition

A high-performance gasket () capable of coping with a reduction in size and developing a sealing property without producing a squeeze-out at the time of attachment and using a material having a hardness range of 30 to 80 degrees (JIS durometer type A), wherein the requirement of W/W&#x3c;0.9 is satisfied where the bonding width of a base part () is (W) and the width thereof at a position half a height from the bonding part of the base part () to the tip end of a main bead part () is (W), the requirement of 1.15&#x3c;H/W&#x3c;1.80 is satisfied where the height from the bonding part of the base part () to the tip end of the main bead part () is (H), the requirement of L/W&#x3e;=3 is satisfied where the length of the non-bonded portion of the base part () around the cross-section thereof excluding the bonded portion is (L), and the compressibility of the gasket when compressed is 13.5% or higher.

Gasket

A fluoroelastomer composition, which comprises 100 parts by weight of vinylidene fluoride-perfluoro(methyl vinyl ether)-tetrafluoroethylene terpolymer or vinylidene fluoride-hexafluoropropene copolymer, and 10-50 parts by weight of liquid fluoroelastomer having a viscosity of 500 to 3,000 cps at 100&#xb0; C., can be made cross-linkable or vulcanizable fluoroelastomer composition upon further addition of 0.5 to 5 parts by weight of an organic peroxide and 0.5 to 10 parts by weight of a polyfunctional unsaturated compound or further addition of 0.5 to 10 parts by weight of a polyol-based vulcanizing agent thereto. The fluoroelastomer composition can give a cross-linked or vulcanized product having a hardness (Durometer A) of not more than 50 and distinguished processability and compression set resistance characteristics.

Fluoroelastomer composition

A fluororubber composition includes a polyol-crosslinkable fluororubber, a crosslinking accelerator, a polyol crosslinking agent and calcium hydroxide, with the crosslinking accelerator having a specific weight ratio relative to the polyol crosslinking agent, and is heat treated under specific conditions to give a low-friction fluororubber crosslinked product that is well balanced and excellent in properties such as low frictional properties, low tackiness and low resilience properties and that is favorably employed as rubber vibration insulators and impact-absorbing stoppers represented by HDD stoppers.

Method for producing low friction fluorine rubber crosslinked body

A fluoroelastomer composition, which comprises 100 parts by weight of vinylidene fluoride-perfluoro(methyl vinyl ether)-tetrafluoroethylene terpolymer or vinylidene fluoride-hexafluoropropene copolymer, and 10&#x2013;50 parts by weight of liquid fluoroelastomer having a viscosity of 500 to 3,000 cps at 100&#xb0; C., can be made cross-linkable or vulcanizable fluoroelastomer composition upon further addition of 0.5 to 5 parts by weight of an organic peroxide and 0.5 to 10 parts by weight of a polyfunctional unsaturated compound or further addition of 0.5 to 10 parts by weight of a polyol-based vulcanizing agent thereto. The fluoroelastomer composition can give a cross-linked or vulcanized product having a hardness (Durometer A) of not more than 50 and distinguished processability and compression set resistance characteristics.

A hard disc drive cover-integrated gasket, which comprises a metallic cover and a packing material integrated with the metallic cover, the packing material being a molding material from a mixture comprising 100 parts by weight of EPDM or a blend of EPDM and polystyrene type thermoplastic elastomer, 10&#x2013;100 parts by weight of polypropylene type resin, 20&#x2013;130 parts by weight of a plasticizer and 0.1&#x2013;10 parts by weight of a cross-linking agent is easy to fabricate and has distinguished characteristics as low outgassing characteristics, low hardness, good sealability at elevated temperatures, etc.

Hard disc drive cover-integrated gasket

A protruding part formed on one split end part of a boot is temporarily fixed to a recessed part formed on the other split end part in the state where step-shaped hook portions formed on one-end thereof are engagingly locked to each other, and connected by welding, fusion or adhesion. The protruding part is hooked only in one thickness directional side. An overlapping protruding part formed on the non-hook side (inner side) of the recessed part is connected extending over the inside surface of the protruding part and the inside surface of the split end part continued thereto.

Split boots and method of connecting the boots, depositing agent, and heating body

An NBR composition comprising: an NBR; (A) a carbocyclic phosphite compound represented by the following general formula,

Nitrile butadiene rubber composition

A method for preparing a rubber seal product of a type which contacts a metal surface for sealing thereof, comprising the steps of: preparing a rubber composition comprising acrylonitrile butadiene rubber (NBR), (A) a carbocyclic phosphite compound represented by the general formula ##STR1## where R is an alkyl group having 8 to 24 carbon atoms, or a phenyl group having a mono-, di- or tri-substituted alkyl group having 1 to 10 carbon atoms, and (B) an acid phosphate compound represented by the general formula ##STR2## where R' is a hydrogen atom, or an alkyl group having 1 to 13 carbon atoms, and R' is an alkyl group having 1 to 13 carbon atoms, the phosphate compound having an acid number of about 150 to 800 KOH mg/g; wherein a total of about 5 to 20 parts by weight of compound (A) and compound (B) are present in the composition based on 100 parts by weight of NBR, vulcanizing the rubber composition to obtain a vulcanized rubber composition; and compressing the vulcanized rubber composition toward a metal surface.

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Fujisawa, Japan

Kenichi Fujimoto