A rubber composition for a tire according to an embodiment of the present technology includes: 100 parts by mass of a diene rubber and from 1 to 30 parts by mass of a thermally expandable microcapsule composite body, and the thermally expandable microcapsule composite body contains one or more thermally expandable microcapsules and an acrylonitrile butadiene copolymer and/or a crosslinked body thereof covering the one or more thermally expandable microcapsules.

A rubber composition contains: at least one rubber component selected from the group consisting of an ethylene propylene diene rubber, a chloroprene rubber, a nitrile rubber, and an acrylic rubber; 1.5 to 30 parts by mass of a fluorene-modified cellulose nanofiber per 100 parts by mass of the rubber component; and 30 to 120 parts by mass of a carbon-based filler per 100 parts by mass of the rubber component. A method of producing a rubber composition comprises: kneading a dispersion of a fluorene-modified cellulose nanofiber in a process oil and a rubber component to prepare a kneaded material; and mixing a vulcanizing agent into the kneaded material.

A rubber composition contains: at least one rubber component selected from the group consisting of an ethylene propylene diene rubber, a chloroprene rubber, a nitrile rubber, and an acrylic rubber; 1.5 to 30 parts by mass of a fluorene-modified cellulose nanofiber per 100 parts by mass of the rubber component; and 30 to 120 parts by mass of a carbon-based filler per 100 parts by mass of the rubber component. A method of producing a rubber composition comprises: kneading a dispersion of a fluorene-modified cellulose nanofiber in a process oil and a rubber component to prepare a kneaded material; and mixing a vulcanizing agent into the kneaded material.

A sealing member includes a sliding portion made of a vulcanized rubber composition. The rubber composition includes a carboxyl-containing acrylic rubber, a silica, and a glass fiber. A content of the silica is 25 to 100 parts by weight per 100 parts by weight of the carboxyl-containing acrylic rubber.

A sealing member includes a sliding portion made of a vulcanized rubber composition. The rubber composition includes a carboxyl-containing acrylic rubber, a silica, and a glass fiber. A content of the silica is 25 to 100 parts by weight per 100 parts by weight of the carboxyl-containing acrylic rubber.

A sealing member includes a sliding portion made of a vulcanized rubber composition. The rubber composition includes a carboxyl-containing acrylic rubber, a silica, and a glass fiber. A content of the silica is 25 to 100 parts by weight per 100 parts by weight of the carboxyl-containing acrylic rubber.

Provide is a rubber composition for a tire that improves mechanical properties beyond conventional levels. The rubber composition for a tire according to an embodiment of the present invention contains from 1 to 50 parts by mass of oxidized cellulose nanofibers blended in 100 parts by mass of diene rubber containing 5% by mass or greater of modified diene rubber having 0.1% by mol or greater of a polar group.

Provide is a rubber composition for a tire that improves mechanical properties beyond conventional levels. The rubber composition for a tire according to an embodiment of the present invention contains from 1 to 50 parts by mass of oxidized cellulose nanofibers blended in 100 parts by mass of diene rubber containing 5% by mass or greater of modified diene rubber having 0.1% by mol or greater of a polar group.

A disclosed crosslinkable rubber composition includes a carboxyl group-containing nitrile rubber (A) containing a halogen or a halogen compound, and having an iodine value of 120 or less; a polyamine-based crosslinking agent (B); and a metal-based acid acceptor (C).

A disclosed crosslinkable rubber composition includes a carboxyl group-containing nitrile rubber (A) containing a halogen or a halogen compound, and having an iodine value of 120 or less; a polyamine-based crosslinking agent (B); and a metal-based acid acceptor (C).