In a pneumatic tire in which a reinforcing layer including a cord is embedded, a coating rubber covering the cord included in the reinforcing layer uses a rubber composition in which 30 parts by mass to 60 parts by mass of carbon black having a nitrogen adsorption specific surface area N.sub.2SA of 100 m.sup.2/g or more and 0 parts by mass or more and 10 parts by mass or less of aroma oil is optionally blended, per 100 parts by mass of a rubber component containing 70 mass % to 100 mass % of a natural rubber and in which a strength at break TB (unit: MPa) at 100° C. and a stress M100 (unit: MPa) at 100% elongation at 100° C. satisfy a relationship TB.sup.2/M100≥50.0.

In a pneumatic tire in which a reinforcing layer including a cord is embedded, a coating rubber covering the cord included in the reinforcing layer uses a rubber composition in which 30 parts by mass to 60 parts by mass of carbon black having a nitrogen adsorption specific surface area N.sub.2SA of 100 m.sup.2/g or more and 0 parts by mass or more and 10 parts by mass or less of aroma oil is optionally blended, per 100 parts by mass of a rubber component containing 70 mass % to 100 mass % of a natural rubber and in which a strength at break TB (unit: MPa) at 100° C. and a stress M100 (unit: MPa) at 100% elongation at 100° C. satisfy a relationship TB.sup.2/M100≥50.0.

The invention relates to footwear with a rubber sole and to such rubber sole where the sole is provided with a rubber composition which contains dual precipitated silica moieties. The dual precipitated silica moieties are provided in a sense of being comprised of hydrophilic precipitated silica and hydrophobic precipitated silica.

The invention relates to footwear with a rubber sole and to such rubber sole where the sole is provided with a rubber composition which contains dual precipitated silica moieties. The dual precipitated silica moieties are provided in a sense of being comprised of hydrophilic precipitated silica and hydrophobic precipitated silica.

A rubber composition includes: 100 parts by mass of a nitrile rubber (A); 10 to 300 parts by mass of a white filler (B); 0.3 to 10 parts by mass of a paraffin wax (C); and 0.5 to 5 parts by mass of a dithiocarbamic acid salt-based antioxidant (D). The nitrile rubber (A) has a content of an acrylonitrile unit of 19 to 30 mass %, and the paraffin wax (C) has a melting point of 45 to 100° C.

A rubber composition includes: 100 parts by mass of a nitrile rubber (A); 10 to 300 parts by mass of a white filler (B); 0.3 to 10 parts by mass of a paraffin wax (C); and 0.5 to 5 parts by mass of a dithiocarbamic acid salt-based antioxidant (D). The nitrile rubber (A) has a content of an acrylonitrile unit of 19 to 30 mass %, and the paraffin wax (C) has a melting point of 45 to 100° C.

Provided are copolymers which provide improved overall performance in terms of fuel economy and wet grip performance, as well as rubber compositions and tires containing the copolymers. Included is a copolymer obtained by copolymerizing an aromatic vinyl compound, a conjugated diene compound, and a compound represented by the formula (1) below or by copolymerizing a conjugated diene compound and a compound represented by the formula (1) below, the copolymer having a weight average molecular weight of 1.0×10.sup.3 to 2.5×10.sup.6, ##STR00001##
wherein R.sup.1 and R.sup.2 may be the same or different and each represents a functional group containing at least two selected from the group consisting of carbon, hydrogen, and silicon, and R.sup.1 and R.sup.2 may be joined together to form a ring structure.

Provided are copolymers which provide improved overall performance in terms of fuel economy and wet grip performance, as well as rubber compositions and tires containing the copolymers. Included is a copolymer obtained by copolymerizing an aromatic vinyl compound, a conjugated diene compound, and a compound represented by the formula (1) below or by copolymerizing a conjugated diene compound and a compound represented by the formula (1) below, the copolymer having a weight average molecular weight of 1.0×10.sup.3 to 2.5×10.sup.6, ##STR00001##
wherein R.sup.1 and R.sup.2 may be the same or different and each represents a functional group containing at least two selected from the group consisting of carbon, hydrogen, and silicon, and R.sup.1 and R.sup.2 may be joined together to form a ring structure.

The present invention provides the rubber composition for a golf ball comprising (a) a base rubber, (b) a co-crosslinking agent which is an α,β-unsaturated carboxylic acid or a metal salt thereof or both, (c) a crosslinking initiator, and (d) an alcohol, wherein the amount of component (d) is from 0.1 to 10 parts by weight per 100 parts by weight of the base rubber (a) and the compounding ratio between component (b) and component (c) is set to at least 60 of E value that is represented by “E=the molar amount of component (b)/the molar amount of the active oxygen of component (c), and a golf ball using the rubber composition, in order to achieve the object that good durability of the golf ball to impact is maintained.

The present invention provides a rubber composition obtained by kneading a rubber component, a vulcanization accelerator, silica, and a compound represented by the following formula (I): ##STR00001##
wherein the groups are as defined in the DESCRIPTION.