The present invention relates to the use of N,N′,N″-substituted hexahydro-1,3,5-triazine in the anionic polymerization of conjugated diene monomer and vinylaromatic monomer. Use of this polar additive produces copolymers having both high vinylaromatic and low vinyl contents, while the blockiness of the vinylaromatic unit can be tailored.

A styrenic block copolymer having one or more polymer blocks A and one or more polymer blocks B is disclosed, where “A” is a poly(vinylaromatic) block having a molecular weight of greater than 5 kg/mol. The “B” block has a molecular weight of more than 15 kg/mol, and comprises polymerized 1,3-diene units and vinylaromatic units, wherein the polymerized vinylaromatic units represent 5-40 wt. % of the overall weight of the block “B”. The polymerized 1,3-diene units comprise more than 80 wt. % of polymerized isoprene units in which 45-80 mol % are 1,4-isoprene addition units. The blocks “A” and “B” represent from >5 to <40 wt. %, and >33 to <95 wt. %, respectively, relative to the overall weight of the block copolymer. The polymers have physical properties that make them valuable, e.g., as vibration damping materials.

A tire comprises a directional tread of width (W), having a total volume VT, comprising voids (221, 211, 212) defining a voids volume VE. There is defined a volumetric voids ratio TEV=VE/VT, part of the voids (211) delimits blocks (21A, 21B) which are organized into patterns (26) of blocks of pitch P succeeding one another in the circumferential direction (X). Part of the voids forms sipes (211, 212) in one of the patterns. The sipes density SD corresponds to the ratio of a sum of the projected lengths (lpyi) of the sipes in an axial direction to the product of the pitch P of the pattern times the width (W), all multiplied by 1000. SD in any pattern of pitch P is comprised between 10 mm.sup.−1 and 70 mm.sup.−1. TEV is at least equal to 0.29 and at most equal to 0.35.

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 rubber composition for tires according to an embodiment includes a diene rubber, a filler, and a fatty acid ester of a polyoxyalkylene glyceryl ether, and 50 mass % or more of the filler is carbon black. A tire according to an embodiment includes the rubber composition for tires.

A tread additive composition to be combined with a base composition for tire treads to achieve low rolling resistance includes an elastomeric component, a first additive component, and a second additive component. The elastomeric component includes a first silane-grafted polyolefine elastomer. The first additive component including a polymer carrier, a reinforcing filler, silane-terminated liquid polybutadienes, and one or more process activators. The second additive component including a butadiene rubber, a hydrocarbon resin, sulfur; and one or more accelerators. Advantageously, the tread additive composition can decrease rolling resistance and improve fuel economy when combined with a base tread composition as compared to treads formed from the base tread composition without the tread additive composition.

Rubber components of a tire comprising a diene elastomer and at least 1 phr of reduced graphene oxide nanoparticles having a specific surface area of at least 700 m.sup.2/g, an oxygen content of no more than 6 at %, and a ratio of non-aromaticity to aromaticity I.sub.D/I.sub.G of at least 0.7 as determined by Raman spectroscopy. Methods of preparing such rubber compositions in an internal mixer for achieving good distribution and dispersion are also included.

To provide a method for producing a multicomponent copolymer with which a multicomponent copolymer having excellent rupture strength can be obtained, and a multicomponent copolymer, a rubber composition and a tire having excellent rupture strength. The method is a method for producing a multicomponent copolymer having a conjugated diene unit, a non-conjugated olefin unit and an aromatic vinyl unit, comprising adding a conjugated diene compound in divided portions into a reactor containing a catalyst and at least one selected from the group consisting of a non-conjugated olefin compound and an aromatic vinyl compound. The multicomponent copolymer is obtained with the production method. The rubber composition comprises the multicomponent copolymer as a rubber component. The tire uses the rubber composition.

A rubber composition for a tire, which does not require the addition of a compound when synthesizing rubber component and the modification of a rubber component, and a studless tire using the rubber composition are provided. The rubber composition for a tire contains fine particles of rotaxane having a straight chain molecule, a cyclic molecule clathrating the straight chain molecule and blocking groups arranged at both terminals of the straight chain molecule such that the cyclic molecule does not desorb from the straight chain molecule, covered with silica; a rubber component including natural rubber and butadiene rubber; and carbon black, wherein the total content of the fine particles and the carbon black is 30 to 60 parts by mass per 100 parts by mass of the rubber component.

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.