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.

A composition for seeded polymerization includes: a seed copolymer which has a compound having dithioate, a mercaptan compound, a first aromatic vinyl monomer, and a first conjugated diene monomer, and has an average particle diameter of 10-30 nm; a second aromatic vinyl monomer; and a second conjugated diene monomer.

A rubber compound for a tire tread includes more than a 30% maximum difference in styrene content between a pair of functionalized diene elastomers. At least one of the diene elastomers contains a functional group that can interact with a precipitated silica that is also in the composition.

Acoustic medium of ultrasonic grip system consists of piezoelectric generator (1), wheel knuckle (9), ball bearing (10), wheel hub (11), wheel rim (15) and tyre of motor-car (20). The piezoelectric generator (1) creates ultrasound vibrations which are transferred through the acoustic medium to the surface of tyre (17). The ultrasound vibration on the surface of tyre (17) results in the separation of the surface of tyre (17) from the liquid (18) that may be found on tarmac (19) during the rain, which results in the fact that despite the unfavourable weather conditions the motor-car has an optimum rolling surface of tarmac. Also, the vibrations on the surface of tyre (17) in interaction with micro texture of tarmac increases the contact surface of tyre with tarmac, which results in the increase of coefficient of friction, higher grip of tyre and reduction of braking distance of motor-car. The ultrasonic grip system is activated at sudden braking, resp. activation of ABS system. Also, the system is activated on the occasion of activating the ESP and ASR system.

The invention relates to a copolymer of ethylene and of a 1,3-diene of formula CH.sub.2═CR—CH═CH.sub.2, which copolymer bears a silanol or alkoxysilane function, the symbol R representing a hydrocarbon chain having from 3 to 20 carbon atoms. Such a copolymer improves the compromise between the content of ethylene in the polymer, its crystallinity and the stiffness of a rubber composition containing it.

The invention relates to a copolymer of ethylene and of a 1,3-diene of formula CH.sub.2═CR—CH═CH.sub.2, which copolymer bears a silanol or alkoxysilane function, the symbol R representing a hydrocarbon chain having from 3 to 20 carbon atoms. Such a copolymer improves the compromise between the content of ethylene in the polymer, its crystallinity and the stiffness of a rubber composition containing it.

A motorcycle tyre (1) is described comprising an equatorial plane (X-X) and a tread band (8) comprising a radially inner portion (13) and a radially outer portion (11) respectively comprising a first and a second vulcanized elastomeric material obtained by vulcanizing respective elastomeric materials comprising 100 phr of at least one elastomeric diene polymer, from 30 to 130 phr of at least one reinforcing filler comprising an amount greater than 75% or, respectively, equal to or greater than 80% of a white filler. In the tyre (1) the ratio R1 between the dynamic elastic modulus (E′) and the tandelta measured at a frequency of 10 Hz and at 70° C. of the first vulcanized elastomeric material is comprised between 27 and 35, whereas the ratio R2 between the dynamic elastic modulus (E′) and the tandelta measured at a frequency of 10 Hz and at 70° C. of the second vulcanized elastomeric material is comprised between 15 and 30, the ratio R1/R2 being greater than or equal to 1.1.

The invention relates to an assembly for a tyre comprising a first fabric, a second fabric and a load-bearing structure comprising filamentary load-bearing elements made of heat-shrinkable textile material connecting the first fabric to the second fabric, the load-bearing filamentary elements exhibit a thermal contraction CT, measured after 2 min at 185° C., greater than or equal to 5%.

The invention relates to a sulfur-crosslinkable rubber mixture and to a pneumatic vehicle tire comprising at least one rubber component made of the sulfur-vulcanized rubber mixture.

The rubber mixture contains 10-60 phr (parts by weight, based on 100 parts by weight of the total rubbers in the mixture) of at least one functionalized polybutadiene A,
wherein the functionalized polybutadiene A is functionalized at one chain end with an organosilyl group containing amino groups and/or ammonium groups,
and wherein the functionalized polybutadiene A is functionalized at the other chain end with an amino group, up to 90 phr of at least one further diene rubber and 30-350 phr of at least one filler.

The invention relates to a sulfur-crosslinkable rubber mixture and to a pneumatic vehicle tire comprising at least one rubber component made of the sulfur-vulcanized rubber mixture.

The rubber mixture contains 10-60 phr (parts by weight, based on 100 parts by weight of the total rubbers in the mixture) of at least one functionalized polybutadiene A,
wherein the functionalized polybutadiene A is functionalized at one chain end with an organosilyl group containing amino groups and/or ammonium groups,
and wherein the functionalized polybutadiene A is functionalized at the other chain end with an amino group, up to 90 phr of at least one further diene rubber and 30-350 phr of at least one filler.