A rubber composition, which exhibits an improved fatigue strength and stiffness performance compromise, is based on at least one elastomer matrix containing at least one polyisoprene and at least one copolymer containing ethylene units and diene units; a paraffin oil having a glass transition temperature of less than -75° C.; a reinforcing filler comprising carbon black; and a crosslinking system, in which the at least one polyisoprene and the at least one copolymer containing ethylene units and diene units represent more than 40% by weight of the elastomer matrix.

A rubber composition, which exhibits an improved fatigue strength and stiffness performance compromise, is based on at least one elastomer matrix containing at least one polyisoprene and at least one copolymer containing ethylene units and diene units; a paraffin oil having a glass transition temperature of less than -75° C.; a reinforcing filler comprising carbon black; and a crosslinking system, in which the at least one polyisoprene and the at least one copolymer containing ethylene units and diene units represent more than 40% by weight of the elastomer matrix.

The invention relates to a process which responds to this problem scenario. The invention therefore relates to a process for preparing a rubber composition based on at least one diene elastomer, a reinforcing filler, a crumb rubber and a crosslinking system, said process comprising at least the following steps: incorporating the reinforcing filler into the diene elastomer, all at once or in several stages, and mixing; when the temperature of the mixture reaches a temperature of greater than 100° C., adding the crumb rubber; continuing the mixing up to a maximum temperature of between 120° C. and 190° C.; cooling the mixture to a temperature of less than 100° C.; incorporating the crosslinking system and mixing up to a maximum temperature of less than 110° C.

The invention relates to a process which responds to this problem scenario. The invention therefore relates to a process for preparing a rubber composition based on at least one diene elastomer, a reinforcing filler, a crumb rubber and a crosslinking system, said process comprising at least the following steps: incorporating the reinforcing filler into the diene elastomer, all at once or in several stages, and mixing; when the temperature of the mixture reaches a temperature of greater than 100° C., adding the crumb rubber; continuing the mixing up to a maximum temperature of between 120° C. and 190° C.; cooling the mixture to a temperature of less than 100° C.; incorporating the crosslinking system and mixing up to a maximum temperature of less than 110° C.

The present disclosure provides a tire which makes it possible to reduce the increase in hardness and the decrease in wet grip performance from before to after heat aging. The present disclosure relates to a tire including a tread, the tread including an elastomer composition containing a styrene elastomer and urethane particles, the tread satisfying the following relationship (1): (M100a−M100f)/M100f×100≤38 wherein M100f represents the stress at 100% elongation (23° C.) before heat aging, and M100a represents the stress at 100% elongation (23° C.) after heat aging.

The present disclosure provides a tire which makes it possible to reduce the increase in hardness and the decrease in wet grip performance from before to after heat aging. The present disclosure relates to a tire including a tread, the tread including an elastomer composition containing a styrene elastomer and urethane particles, the tread satisfying the following relationship (1): (M100a−M100f)/M100f×100≤38 wherein M100f represents the stress at 100% elongation (23° C.) before heat aging, and M100a represents the stress at 100% elongation (23° C.) after heat aging.

An adhesive for a tennis ball of the present disclosure includes base rubber and a filler. The base rubber contains, as a main component thereof, liquid rubber having a number average molecular weight of not less than 10,000. The filler has an average nitrogen specific surface area of not less than 40 m.sup.2/g. A tennis ball of the present disclosure includes a hollow core made of a rubber material. The core includes two hemispherical half cores. The two half cores are adhered to each other by using the adhesive for a tennis ball.

An adhesive for a tennis ball of the present disclosure includes base rubber and a filler. The base rubber contains, as a main component thereof, liquid rubber having a number average molecular weight of not less than 10,000. The filler has an average nitrogen specific surface area of not less than 40 m.sup.2/g. A tennis ball of the present disclosure includes a hollow core made of a rubber material. The core includes two hemispherical half cores. The two half cores are adhered to each other by using the adhesive for a tennis ball.

It is an object to provide a tire having well-improved fuel efficiency, wet grip performance, abrasion resistance, and wet grip performance at a later stage of abrasion. Provided is a tire comprising a tread part of a rubber composition comprising a rubber component comprising an isoprene-based rubber and a styrene-butadiene rubber, wherein a vinyl content of the styrene-butadiene rubber is greater than 26 mol %, wherein a given ratio A of an ash content of the rubber composition is greater than 25 mol %, wherein the tread part comprises two or more circumferential main grooves extending in a tire circumferential direction, and land parts partitioned by the circumferential main grooves, wherein at least one land part of the land parts comprises at least one given flask-like circumferential groove extending in the tire circumferential direction.

It is an object to provide a tire having well-improved fuel efficiency, wet grip performance, abrasion resistance, and wet grip performance at a later stage of abrasion. Provided is a tire comprising a tread part of a rubber composition comprising a rubber component comprising an isoprene-based rubber and a styrene-butadiene rubber, wherein a vinyl content of the styrene-butadiene rubber is greater than 26 mol %, wherein a given ratio A of an ash content of the rubber composition is greater than 25 mol %, wherein the tread part comprises two or more circumferential main grooves extending in a tire circumferential direction, and land parts partitioned by the circumferential main grooves, wherein at least one land part of the land parts comprises at least one given flask-like circumferential groove extending in the tire circumferential direction.