The present invention is directed to a rubber composition comprising: 70 phr to 100 phr of at least one styrene butadiene rubber, 0 phr to 30 phr of at least one further diene-based rubber, from 40 phr to 200 phr of at least one filler, at least 5 phr of aluminum hydroxide, and at least 10 phr of at least one hydrocarbon resin selected from one or more of DCPD resins, CPD resins, and C5 resins. Furthermore, the present invention is directed to a tire comprising such a rubber composition.

A method of producing a polymer composition is provided, including: kneading (A) a conjugated diene-based polymer that is a polymer of a conjugated diene compound or a copolymer of a conjugated diene compound and an aromatic vinyl compound, and is a reaction product between an active polymerization end and a compound represented by any one of the general formulae (1) to (3), and (B) a basic compound having an acid dissociation constant of 8.0 or more; and kneading a kneaded product from (A) and a crosslinking agent.

It could be helpful to provide a rubber composition that can achieve both reinforcement property and low loss property at a high level. In order to solve the aforementioned problems, the disclosure is a rubber composition comprising a rubber component, carbon black, and silica, wherein the silica has a CTAB adsorption specific surface area of 250 m.sup.2/g or more; the silica has a diameter in the form of aggregates (D.sub.CPS) and a primary particle diameter (D.sub.I), as measured by disk centrifugal particle size analysis, that satisfy: 700≥D.sub.CPS.sup.3/D.sub.I.sup.3≥300 (1); the rubber component contains at least one selected from natural rubber and polyisoprene rubber, and at least one selected from modified butadiene rubber and modified styrene butadiene rubber; and the carbon black is contained by a mass ratio of 70% or more with respect to the total mass content of the carbon black and the silica.

Provided is a pneumatic tire having both improved run-flat durability and excellent wet grip properties; the pneumatic tire including a rubber composition used in a tread part, and a rubber support layer having a gauge thickness in a specified range; the rubber composition including specified compounded amounts of natural rubber, a terminal-modified styrene-butadiene rubber, silica, and a thermoplastic resin, wherein the rubber composition is largely strain-dependent for the storage elastic modulus.

A modified conjugated diene-based polymer and a rubber composition including the same are disclosed herein. In some embodiments, the modified conjugated diene-based polymer includes a functional group derived from a modification monomer represented by Formula 1 and a functional group derived from a modifier, and the polymer has a unimodal molecular weight distribution, and a polydispersity index of 1.0 to less than 1.7. The polymer has excellent processability, tensile properties and viscoelasticity properties.

A modified conjugated diene-based polymer and a rubber composition including the same are disclosed herein. In some embodiments, the modified conjugated diene-based polymer includes a functional group derived from a modification monomer represented by Formula 1 and a functional group derived from a modifier, and the polymer has a unimodal molecular weight distribution, and a polydispersity index of 1.0 to less than 1.7. The polymer has excellent processability, tensile properties and viscoelasticity properties.

The present invention relates to a modified conjugated diene-based polymer and a rubber composition including the same, and provides a modified conjugated diene-based polymer satisfying the following: a) a molecular weight distribution curve by gel permeation chromatography (GPC) has a unimodal shape; b) molecular weight distribution (PDI: MWD) is 1.00 or more and less than 1.70; c) cold flow is 1.00 or less; and d) the Si content is 100 ppm or more based on a total weight of the modified conjugated diene-based polymer.

The present disclosure relates to a modified conjugated diene-based polymer and a rubber composition including the same, and provides a modified conjugated diene-based polymer including: a derived unit from a modification initiator; a repeating unit derived from a conjugated diene-based monomer; and a derived unit from a modifier, and satisfying the conditions of i) a weight average molecular weight: 1,000,000 g/mol or more, ii) a glass transition temperature: −40° C. or less, iii) the N content: 70 ppm or more based on a total weight of the polymer, iv) the Si content: 70 ppm or more based on a total weight of the polymer, and v) a coupling number: greater than 2.5 and less than 5.0.

The present disclosure relates to a modified conjugated diene-based polymer and a rubber composition including the same, and provides a modified conjugated diene-based polymer including a first polymer chain and a second polymer chain, including a repeating unit derived from a conjugated diene-based monomer and a derived unit from a nitrogen-containing modification initiator, in each, wherein the first polymer chain includes a derived unit from an aminoalkoxysilane-based modifier in at least one terminal, the second polymer chain includes a derived unit from an aminoepoxy-based modifier in at least one terminal, and the aminoalkoxysilane-based modifier includes 6 or more alkoxy groups in a molecule.

To provide a narrow and large-diameter tire capable of improving noise performance at high speeds without compromising handling performance at low temperatures.

The tire has a tread portion formed of an elastomer composition. A relationship between a tire outer diameter (Dt) and a tire cross-sectional width (Wt) satisfy a following expression (1). The tread portion includes at least one circumferential groove extending in a tire circumferential direction. A rubber thickness at a groove bottom of the circumferential groove is 0.05 to 0.25 times a maximum thickness of the tread portion. The elastomer composition has a phase difference δ of 5.0×10.sup.−2π [rad] or less between a maximum value of strain and a maximum value of stress when repeatedly deformed at a temperature of 30 degrees Celsius and a frequency of 10 Hz in a dynamic viscoelasticity test;

1963.4≤(Dt.sup.2×π/4)/Wt≤2827.4  (1).