To provide a catalyst composition having high polymerization activity. To provide a polymer manufacturing method. To provide a polymer manufactured by the polymer manufacturing method. To provide a rubber composition including the polymer. To provide a tire using the rubber composition. A catalyst composition including a compound represented by Structural Formula I below, wherein the compound has an OH group at at least one position of the bipyridyl ring; M is a transition metal, a lanthanoid, scandium, or yttrium; R.sup.1 and R.sup.2 are a hydrocarbon group having one or more carbon atoms or a halogen atom; and R.sup.1 and R.sup.2 may be the same or different from each other. A polymer manufacturing method including a step of polymerizing one or more selected from the group consisting of a conjugated diene compound and a compound having an ethylenically unsaturated double bond in the presence of the catalyst composition. A polymer manufactured by the manufacturing method. A rubber composition including the polymer. A tire using the rubber composition. ##STR00001##

A run flat tire having improved run flat durability is provided. The run flat tire has a side wall part reinforced by a side reinforcing rubber part, and the side reinforcing rubber part is formed by a rubber composition which comprises 100 parts by mass of a diene rubber containing natural rubber and polybutadiene rubber, and from 0.1 to 4.0 parts by mass of a mercaptobenzimidazole compound.

A run flat tire having a side reinforcing rubber part is disclosed. The side reinforcing rubber part is formed by a rubber composition having a ratio (M50H/M50N) of tensile stress (M50H) in 50% elongation at a measurement temperature of 100° C. to tensile stress (M50N) in 50% elongation at a measurement temperature of 23° C. of from 1.0 to 1.3. A cushion rubber layer interposed between the side reinforcing rubber part and a bead filler is provided, and tensile stress in 50% elongation at a measurement temperature of 23° C. of a rubber composition forming the cushion rubber layer is larger than tensile stress in 50% elongation at a measurement temperature of 23° C. of the rubber composition forming the side reinforcing rubber part, and is smaller than tensile stress in 50% elongation at a measurement temperature of 23° C. of a rubber composition forming the bead filler.

To provide a rubber compound for tires, a pneumatic tire and an airless tire capable of improving the steering stability of the tire while exerting excellent low fuel consumption performance. A rubber compound for tires characterized in that, of vulcanized rubber's physical properties, a complex elastic modulus E*.sub.70 (unit: MPa) and a loss tangent tanδ.sub.70 under initial strain of 10%, dynamic strain of 2% and temperature of 70 degrees C., satisfy 90<E.sub.70<250, and E*.sub.70/tan δ.sub.70>800. A pneumatic tire provided with a rubber member made of the above-mentioned rubber compound. An airless tire provided with a rubber member made of the above-mentioned rubber compound. An airless tire provided in a tread ring with a shear rubber layer made of the above-mentioned rubber compound.

The present invention is directed to a functionalized elastomer comprising the reaction product of a living elastomeric polymer and a polymerization terminator of formula I, wherein the functionalized elastomer comprises repeat units of a diene monomer and optionally a vinyl aromatic monomer, and the functionalized elastomer comprises at least 92 percent by weight of cis 1,4 microstructure content based on the weight of the polydiene content of the functionalized elastomer ##STR00001##
wherein R.sup.1 is C1 to C4 linear alkyl, or C1 to C4 branched alkanediyl; X.sup.1, X.sup.2, X.sup.3 are independently O, S, or a group of formula (II) or (III) ##STR00002## ##STR00003##
where R.sup.2 is C1 to C18 linear or branched alkyl; Z is R.sup.3, —OR.sup.4, or —R.sup.5—X.sup.4; R.sup.3, R.sup.4 are independently C1 to C18 linear or branched alkyl; R.sup.5 is C1 to C18 alkanediyl or dialkyl ether diyl; X.sup.4 is halogen or a group of structure IV, V, VI, VII or VIII ##STR00004## ##STR00005## ##STR00006## ##STR00007## ##STR00008##
wherein R.sup.6, R.sup.7, R.sup.8, R.sup.9, and R.sup.10 are independently H or C1 to C8 alkyl; R.sup.11 is C2 to C8 alkanediyl; R.sup.12 and R.sup.13 are independently H, aryl or C1 to C8 alkyl;
Q is N or a group of structure IX ##STR00009##
wherein R.sup.14 is C1 to C8 alk.

Provided is novel polybutadiene having high isotacticity. The polybutadiene has a triad isotacticity (mm) of 72% or more.

The present invention is directed to a rubber composition comprising 80 phr to 100 phr of at least one solution polymerized styrene-butadiene rubber, 0 phr to 20 phr of at least one polybutadiene, 55 phr to 200 phr of a filler, at least 15 phr of oil, wherein the filler to oil ratio by weight is between 3.5:1 and 8.0:1, and wherein the weight average molecular weight (Mw) of the at least one solution polymerized styrene-butadiene rubber is within a range of 400,000 to 1,000,000 g/mol. Moreover, the present invention is directed to a tire comprising such a rubber composition.

The invention is directed to a vulcanizable rubber composition comprising, based on parts by weight per 100 parts by weight elastomer (phr):100 phr of at least one diene-based elastomer; from 1-80 phr of carbon black; from 0 to 100 phr of silica; from 1 to 10 phr of a surface-functionalized carbon allotrope; from 1 to 20 parts by weight of a sulfur-containing organosilane per 100 parts by weight of the silica; and from 0.1 to 10 phr of a tetrazine compound of formula 1

##STR00001##

where X.sup.1 and X.sup.2 each represent a heterocyclic group. The invention also includes a pneumatic tire comprising the vulcanizable rubber composition.

A method of preparing a sidewall support, the method comprising the steps of (i) providing a vulcanizable composition including an elastomer, a filler, a curative, and a eutectic composition; (ii) fabricating the vulcanizable composition into a green sidewall support; and (iii) subjecting the green sidewall support to curing conditions.

Microbeads are described, comprising silica fibres with needle-shaped morphology of nanometric size, characterised by reduced dustiness and good dispersibility in elastomeric materials, a process for the preparation thereof and the use thereof in the production of vehicle tyres.