Provided is a rubber composition having excellent low heat generating properties. The rubber composition of the present disclosure contains a rubber component, a filler containing silica, and a silane coupling agent, where the rubber component contains a conjugated diene-based polymer modified with a modifier containing a compound represented by the formula (1), and the silane coupling agent is a compound represented by the formula (2).

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The present invention relates to a modified conjugated diene-based polymer, a method for preparing the same and a rubber composition including the same, and relates to a modified conjugated diene-based polymer which is prepared by continuous polymerization and has excellent processability, a mooney large relaxation area of 300 MU-s to 1000 MU-s, and narrow molecular weight distribution, and if compounded into a rubber composition, shows improved tensile properties and viscoelasticity properties, particularly, a tan δ value at a high temperature (60° C.) among viscoelasticity properties, and excellent low hysteresis properties and fuel consumption properties, and a rubber composition including the same.

Provided is a rubber composition that realizes excellent low heat generating properties while maintaining good steering stability when applied to a tire. The rubber composition of the present disclosure contains a rubber component containing a copolymer having a conjugated diene unit and an aromatic vinyl unit, and a filler, where the copolymer is a modified copolymer having a content of the aromatic vinyl unit of less than 10 mass % and modified with a modifier containing a compound represented by the formula (1).

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The present disclosure provides a tire having excellent enduring performance. The present disclosure relates to a tire including a tread containing a rubber composition, the rubber composition satisfying the following relationships 1) to 3) when measured within 180 days after vulcanization: 1) Hso/Hsa×100≥95 wherein Hso: hardness at room temperature, Hsa: hardness at room temperature after heat treatment at 80° C. for 168 hours; 2) As/Ts×100≤70 wherein Ts: sulfur content before acetone extraction, As: sulfur content after acetone extraction; and 3) Swell≤330 wherein Swell: toluene swelling index.

A method for producing a modified conjugated diene-based polymer includes polymerizing a monomer including a conjugated diene compound in the presence of an alkali metal compound or an alkali earth metal compound to obtain a polymer having an active terminal; (a modification) reacting the polymer having an active terminal with a compound [M] having a plurality of hydrocarbyloxysilyl groups to obtain a modified polymer; and a mixing the modified polymer with at least one compound [C] selected from a compound [N] having one hydrocarbyloxysilyl group and an alcohol having 6 to 20 carbon atoms.

Provided is a pneumatic tire having excellent abrasion resistance and excellent handling stability on an extremely cold road while having a reduced weight. The present disclosure relates to a pneumatic tire, including a tread having a hardness at −20° C. of 90 or less, a hardness at 30° C. of 60 or more, and a maximum thickness of 8.5 mm or less, and a carcass including one carcass ply.

A modifying agent, a modified conjugated diene polymer prepared using the same, a method for preparing a modified conjugated diene polymer, and a rubber composition including a modified conjugated diene polymer are disclosed herein. In some embodiments, a modifying agent comprises a compound represented by formula 1. The modifying agent is capable of improving processability of a rubber composition including the polymer prepared using the modifying agent. Fuel consumption properties of a car using tires including the rubber composition may be improved.

The present invention provides a compounding agent which, when used in a rubber composition containing a reinforcing filler, exhibits excellent dispersibility, workability, toughness, low heat build-up, and wear resistance; and a rubber composition containing the compounding agent. A modified butadiene polymer of the present invention has a functional group containing a nitrogen atom and silicon atom at a terminal, a weight average molecular weight of the modified butadiene polymer being from 1000 to 15000, and a molecular weight distribution of the modified butadiene polymer being 2.0 or less.

The present invention provides a run-flat tire excellent in run-flat durability. In the run-flat tire, a vulcanized rubber of a rubber composition containing a rubber component and a vulcanization accelerator that contains tetrabenzylthiuramdisulfide is used for at least one member selected from the group consisting of a side-reinforcing rubber layer and a bead filler. In the vulcanized rubber of the run-flat tire, a proportion of monosulfide bonds and disulfide bonds in all sulfide bonds is 65% or more.

An end-group functionalized polymer having one or more end groups according to the general formula (I)

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wherein
R1 represents a saturated or unsaturated, linear or branched, preferably aliphatic, hydrocarbon group having from 1 to 20 carbon atoms which, in addition to C and H, may contain one or more heteroatoms, preferably independently of one another selected from O, N, S or Si;
R2, R3 are identical or different and represent saturated or unsaturated hydrocarbon groups having from 1 to 20 carbon atoms and wherein the hydrocarbon group may contain, in addition to C and H atoms, one or more heteroatoms, preferably selected from the group consisting of O, N, S and Si;
A represents a residue selected from the group consisting of O-R4-OH, R5-OH and R6-NH-R7, preferably O-R4-OH wherein R4, R5 and R6 represent a saturated or unsaturated linear or branched hydrocarbon group which, in addition to C and H atoms, may contain one or more heteroatoms, independently selected from O, N, S or Si and which contains from 1 to 20 carbon atoms and wherein
R7 represents H or a linear or branched or cyclic aliphatic or aromatic hydrocarbon group having from 1 to 20 carbon atoms and which, in addition to C and H atoms, may contain one or more heteroatoms, preferably selected from O, N, S or Si;
and wherein the polymer is a homopolymer of a conjugated diene or a copolymer of at least one or more conjugated diene and one or more vinylaromatic monomer and, optionally one or more other comonomers. Also provided are a process for making the polymers and articles made with the polymers.