A rubber composition has an improved rolling resistance and is based on at least a diene elastomer comprising mainly at least one isoprene elastomer; a reinforcing filler comprising from 5 to 60 phr of carbon black having a BET specific surface area of less than 70 m.sup.2/g, termed coarse carbon black, and from 10 to 30 phr of carbon black having a BET specific surface area of greater than or equal to 70 m.sup.2/g, termed fine carbon black; a salt of an alkali, alkaline-earth or lanthanide metal; and a crosslinking system.

The invention relates to a sulfur-crosslinkable rubber mixture, in particular for rubber-coating reinforcements in elastomer products, especially in vehicle tires, or inner components of vehicle tires, as well as to a vehicle tire. The rubber mixture contains at least the following components: at least one diene rubber; at least one adhesive system; 10 to 200 phr of at least one silicic acid; and 2 to 20 phf of at least one silane of the general empirical formula I) [(R1)3Si-X]mSn(R2)2-m, where the residues R1 can be identical or different within a molecule and are alkoxy groups comprising 1 to 10 carbon atoms, cyclic d1 alkoxy groups comprising 2 to 10 carbon atoms, cycloalkoxy groups comprising 4 to 10 carbon atoms, phenoxy groups or aryl groups comprising 6 to 20 carbon atoms, alkyl groups comprising 1 to 10 carbon atoms, alkenyl groups comprising 2 to 20 carbon atoms, aralkyl groups comprising 7 to 20 carbon atoms, or halides, and where X is a polar organic group containing urea, m represents the value 1 or 2, n is an integer between 1 and 8, and R2 is a hydrogen atom or an acyl group comprising 1 to 20 carbon atoms.

A rubber composition exhibiting an improved processability/stiffness compromise is based on at least a diene elastomer, a reinforcing filler, a crosslinking system, between 1 and 30 parts by weight per hundred parts by weight of elastomer, phr, of an epoxy resin and between 1 and 15 phr of a specific amine-comprising hardener comprising in particular at least two primary amine functional groups located on at least one six-membered aromatic ring and at least two Ri radicals, which are identical or different, selected from the group consisting of linear or branched C.sub.1-C.sub.6 alkyl radicals, halogens, and ethers, tertiary amines, thioethers, ketones, esters and amides, substituted by linear or branched C.sub.1-C.sub.6 alkyl radicals, the said ring not comprising a hydrogen atom located in the ortho position with respect to the primary amine functional groups.

A pneumatic tire includes: a bead core; a bead filler; a carcass ply; a side wall rubber that is arranged on the tire-outer-surface-side of the carcass ply and constitutes a tire outer surface; a chafer layer that is turned from the tire-inner-surface-side to the tire-outer-surface-side around the bead core and the bead filler and rolled up on an outer surface of the carcass ply; a pair of support rubbers that are located between the side wall rubber and the carcass ply and arranged so as to hold a rolled-up end of the chafer layer from both sides in a tire width direction; in which modulus values of the pair of support rubbers are higher than a modulus value of the side wall rubber, and hardness of the hardened support rubber is enhanced while scorch resistance of an unvulcanized rubber composition is maintained.

A pneumatic tire includes: a bead core; a bead filler; a carcass ply; a side wall rubber that is arranged on the tire-outer-surface-side of the carcass ply and constitutes a tire outer surface; a chafer layer that is turned from the tire-inner-surface-side to the tire-outer-surface-side around the bead core and the bead filler and rolled up on an outer surface of the carcass ply; a pair of a tape rubber and a rear pad rubber that are located between the side wall rubber and the carcass ply and arranged so as to hold a rolled-up end of the chafer layer from both sides in a tire width direction; and a tread rubber, in which modulus values of the pair of the tape rubber and the rear pad rubber are higher than a modulus value of the side wall rubber, and the tread rubber contains silica.

A modified conjugated diene-based polymer containing: having a weight average molecular weight of 2010.sup.4 or more and 30010.sup.4 or less, having a star-branched structure with a conjugated diene-based polymer chain bonded to a modifier residue, wherein the modifier residue has at least 4 silicon atoms, and alkoxy groups and/or hydroxyl groups and the conjugated diene-based polymer chain is bonded to the silicon atom, wherein the number of alkoxy groups and/or hydroxyl groups in the modifier residue is larger than the number of the silicon atoms on average.

Provided is a pneumatic tire including: a tread portion that extends in a tire circumferential direction and forms an annular shape; a pair of sidewall portions disposed on both sides of the tread portion; and a pair of bead portions disposed on an inner side in a tire radial direction of the sidewall portions, wherein an anti-insect layer having extermination characteristics or repellent characteristics with respect to insect pests is provided on an innermost surface of the pneumatic tire, or a repellent layer having repellent or extermination characteristics with respect to insect pests or small animals is provided on an outer surface of the pneumatic tire.

A method of production of a modified conjugated diene rubber including a first step of polymerizing a monomer containing at least a conjugated diene compound by using a polymerization initiator in an inert solvent so as to obtain a conjugated diene polymer having an active end, and a second step of causing a compound represented by a following formula (1) to react with the active end of the conjugated diene polymer having an active end: ##STR00001## wherein, in formula (1), each of R.sup.1 to R.sup.3 independently is an alkyl group having 1 to 4 carbon atoms, R.sup.4 is a hydrocarbon group containing an aromatic ring and having 6 to 10 carbon atoms, R.sup.5 is an alkyl group having 1 to 6 carbon atoms, and n is an integer of 0 to 10.

A vulcanizable elastomeric composition for tire component is described. The vulcanizable elastomeric composition includes modified silicate fibers as fillers. Moreover, the tire component contains elastomeric materials which are obtainable by vulcanization of the vulcanizable elastomeric composition. A tire for vehicles which includes one or more of the tire components is also described. The vulcanized elastomeric materials are characterized by having good static and dynamic mechanical properties, and particularly low hysteresis. Advantageously, the tire which contains one or more of the tire components has a reduced rolling resistance.

This invention is based upon the discovery that benzoxazine resins can be incorporated into certain rubber compositions to increase the stiffness thereof without increasing hysteresis or reducing tear strength. Such benzoxazine resin reinforced rubber formulations can accordingly be used beneficially in components of rubber products where high stiffness is desirable. Since these benzoxazine resin reinforced rubbers do not increase levels of hysteresis, they can be used in tires components, such as apexes, chaffers, and high stiffness tread blocks without compromising fuel efficiency. This invention more specifically reveals a radial tire having an apex, a chaffer, or a hard tread block segment which is comprised of a rubbery polymer and a benzoxazine resin.