A sealing body for dynamic applications has a Shore A hardness of between 60-100, comprising an elastomer material and carbon nanotubes distributed in the elastomer material in an amount of between 0.1-20 phr, with respect to the total amount of elastomer 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.sup.2/g, and 5 to 15 parts by weight of hydrated amorphous silicon dioxide having a BET specific surface area of 35 to 220 m.sup.2/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.

The invention provides a composition capable of providing a molded article that has excellent heat resistance and a small weight change against oxygen plasma exposure and fluorine plasma exposure during a semiconductor manufacturing step. The composition contains a fluorine-containing polymer and a hyperbranched polymer of a cage silsesquioxane with a specific structure.

Provided area perfluoroelastomer composition containing a perfluoroelastomer and a compound having a perylene skeleton, in which the compound having a perylene skeleton is a compound other than perylene and 3,4,9,10-perylenetetracarboxylic acid diimide; and a sealing material containing a crosslinked product of the perfluoroelastomer composition.

The invention provides a novel polymer, a composition, and a molded article. The polymer contains a constitutional unit represented by the following formula (1):

##STR00001##

wherein X.sup.11 and X.sup.12 are the same as or different from each other, and are each a hydrogen atom, an alkyl group optionally containing a fluorine atom, or a phenyl group; Y.sup.11 is an oxygen atom or a sulfur atom; Rf.sup.11 is a hydrogen atom or an alkyl group optionally containing a fluorine atom; and a is an integer of 1 to 4.

A fluororubber composition is provided including at least two peroxide-crosslinkable fluorine-containing elastomers each containing a structural unit of perfluoroalkoxy vinyl ether.

Provided are a perfluoroelastomer composition containing a perfluoroelastomer, a peroxide crosslinking agent, a co-crosslinking agent that is a diolefin compound, and an organic pigment; and a sealing material containing a crosslinked product of the perfluoroelastomer composition.

An object of the present invention is to provide a macromolecular material that exhibits excellent elongation. The first macromolecular material of the present invention contains the first polymer containing the first structural unit and the second polymer containing the second structural unit. The first structural unit has a guest group in its side chain, and the second structural unit has a host group in its side chain. At least one of the first and the second polymers contains at least one fluorine group. The second macromolecular material of the present invention contains the first structural unit having a guest group in its side chain, the second structural unit having a host group in its side chain, and the third structural unit other than the first and second structural units. At least one of the first, the second, and the third structural units contains at least one fluorine group.

The invention provides a composition capable of providing a molded article that has excellent heat resistance and a small weight change against oxygen plasma exposure and fluorine plasma exposure during a semiconductor manufacturing step. The composition contains a fluorine-containing polymer and a hyperbranched polymer of a cage silsesquioxane with a specific structure.

Provided is a fluoroelastomer crosslinkable composition containing: a polyol-crosslinkable fluoroelastomer (a); and a cross-linking agent (b), wherein the cross-linking agent (b) is at least one selected from the group consisting of a compound represented by the general formula (b1) set forth in the description, a compound represented by the general formula (b2) set forth in the description, and a salt of each of the compounds with an alkali metal, an alkaline earth metal, or an onium compound.