Nok Corporation

Daiki Takekawa

Isao Watanabe

Ryota Shimura

Masahiro Yokoo

A rubber-metal laminate that includes a metal member; and a rubber layer provided on the metal member, wherein the rubber layer has a 100%-modulus value in accordance with JIS K6251 of 8.5 MPa or more and a thickness of 80 μm or more. A gasket that includes the rubber-metal laminate.

Rubber-metal laminate and gasket

A gasket includes an elastic part containing a rubber having a dynamic-to-static ratio, Kd/Kst, of 2.5 or lower, wherein the dynamic-to-static ratio, Kd/Kst, is a ratio between a dynamic spring constant, Kd, and a static spring constant, Kst. The dynamic spring constant, Kd, represents a constant as measured under conditions of 23±2° C., 100 Hz, and a strain amplitude of 0.1% according to JIS K6394:2007, and the static spring constant, Kst, represents a constant as measured under conditions of 23±2° C. and a strain amplitude of 0.1% according to JIS K6394:2007.

Gasket

A hydrogenated NBR composition comprising 30 to 200 parts by weight of titanium oxide and 1 to 8 parts by weight of magnesium oxide, based on 100 parts by weight of hydrogenated NBR. By forming a crosslinked rubber layer of the rubber composition on a metal plate, a gasket material with excellent blister resistance, whose roll kneadability is improved without reducing the rubber strength of hydrogenated NBR, is provided. Moreover, the rubber composition is effective as a rubber raw material for use in soft metal or a high hardness hydrogenated NBR material for which kneading processing is difficult.

Hydrogenated NBR composition

An NBR composition for rubber laminated metal having 1 to 3 parts by weight of sulfur and 1 to 15 parts by weight of a disulfide compound such as 4,4'-dithiodimorpholine or dithiodicaprolactam represented by the general formula RN&#x2014;S&#x2014;S&#x2014;NR (wherein RN is a cyclic linking group formed together with the N atom bonded to the S atom), based on 100 parts by weight of NBR. The rubber composition that can improve the protrusion properties of a rubber layer when used for, for example, a gasket or a brake shim material that is a laminated composite metal laminated with another metal plate.

NBR composition for rubber laminated metal

A gasket material, in which a crosslinked rubber layer compounding 30 to 200 parts by weight of titanium oxide based on 100 parts by weight of NBR or hydrogenated NBR is formed on a metal plate, improves blister resistance, and thus exhibits an excellent effect of preventing rubber peeling of the gasket in the engine and leading to an improvement of engine malfunction. Further, the use of NBR or hydrogenated NBR results in an advantage of low cost relative to that of fluororubber. Therefore, the gasket material of the present invention is effectively used as a cylinder head gasket.

Gasket material

A gasket material comprising a crosslinked fluororubber layer having a micro-hardness of 5 to 25 formed on a metal plate using a fluororubber composition comprising 30 to 70 parts by weight of carbon black having a CTAB specific surface area of 3 to 34 m/g, and 5 to 15 parts by weight of hydrated amorphous silicon dioxide having a BET specific surface area of 35 to 220 m/g, based on 100 parts by weight of fluororubber, wherein the total amount of carbon black and hydrated amorphous silicon dioxide is 80 parts by weight or less.

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Kanagawa, Japan

Daiki Takekawa