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 232 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 232 C. and a strain amplitude of 0.1% according to JIS K6394:2007.

A material for gaskets is disclosed, wherein a metal surface coating layer, a primer layer and a rubber layer are formed, or a metal surface coating layer and a rubber layer are formed on at least a part of one side or both sides of a substrate formed of a metal plate sequentially from the metal plate side, and the metal surface coating layer comprises (A) one or more carbonates selected from the group consisting of Mg carbonate, Co carbonate, Zr carbonate, Mn carbonate, Ni carbonate, and Cu carbonate and (B) one or more selected from the group consisting of silica, alumina, zirconia, and titania.

The invention relates to a piston-cylinder unit (100) comprising a cylinder (110) filled with a fluid (150), a piston (120) slidably guided in the cylinder (110), a piston rod (130) attached to the piston (120), a seal (140), and a lubricant in contact with the seal (140) and with the cylinder (110), the piston (120) and/or the piston rod (130). The lubricant is a polyalphaolefin oil or a polyalkylene glycol oil. The seal (140) is made of chlorine-free acrylonitrile butadiene rubber. The invention also relates to a method for producing the piston-cylinder unit (100).

A rubber-metal laminated gasket material comprising a metal plate and fluororubber or nitrile rubber laminated on the metal plate, wherein an amorphous carbon film having a nanoindentation hardness on a silicon wafer of 10 GPa or more and a film thickness of 200 nm or more is formed on a rubber layer outer surface of the rubber-metal laminated gasket material by a plasma CVD method that supplies a high-frequency power from a high-frequency power source using unsaturated hydrocarbon gas. The rubber-metal laminated gasket material reduces the wear and abrasion of the gasket material due to friction with the seal mating surface under high temperature use.

A cross-linkable nitrile rubber composition has a carboxyl group-containing nitrile rubber (A) with an iodine value of 120 or less, polyamine cross-linking agent (B), and at least one compound (C) selected from an aliphatic alcohol (c1) having 1 to 9 carbon atoms, hydroxyl group-containing aromatic compound (c2), and nitrogen-containing heterocyclic compound (c3).