The tire rubber composition includes 100 parts by mass of a solid rubber (A) having a glass transition temperature (Tg) of not more than 10 C., 0.1 to 50 parts by mass of a modified liquid diene rubber (B) having a functional group derived from a silane compound with a specific structure, and 20 to 200 parts by mass of a filler (C), the modified liquid diene rubber (B) satisfying the following (i) to (iv): (i) the weight average molecular weight (Mw) is 15,000 to 120,000, (ii) the vinyl content is not more than 70 mol %, (iii) the average number of the functional groups per molecule of the modified liquid diene rubber (B) is 1 to 30, and (iv) the glass transition temperature (Tg) is not more than 0 C.

The invention provides a heavy-duty tire rubber composition capable of giving heavy-duty tires which exhibit low heat generation properties and have good abrasion resistance, and also provides a tire tread, a bead filler, a tire belt and a heavy-duty tire which each partially include the composition. The heavy-duty tire rubber composition includes 100 parts by mass of a solid rubber (A), 0.1 to 50 parts by mass of a modified liquid diene rubber (B) having a functional group derived from a silane compound with a specific structure, and 20 to 200 parts by mass of a filler (C), the modified liquid diene rubber (B) satisfying the following (i) and (ii): (i) the weight average molecular weight (Mw) is not less than 1,000 and not more than 120,000, and (ii) the vinyl content is less than 30 mol %.

The present invention relates to a tire (100) for vehicle wheels comprising a tire component comprising a crosslinked elastomeric material obtained by crosslinking a crosslinkable elastomeric composition, wherein said elastomeric composition comprises a polymer blend comprising (a) 50 to 95 percent by weight of a first elastomeric polymer and (b) 5 to 50 percent by weight of a second elastomeric polymer based on the total weight of the polymer blend. The second elastomeric polymer (b) is obtainable by (i) anionic polymerization of at least one conjugated diene monomer and one or more a-olefin monomer(s) in the presence of a polymerization initiator in an organic solvent, and (ii) coupling the polymer chains obtained in (i) by a coupling agent. The second elastomeric polymer (b) has a weight-average molecular weight (Mw) in the range of 5,000-40,000 g/mol and a coupling rate of at least 50 percent by weight.

The present invention provides a tire which has at least one member selected from the group consisting of a side reinforcing rubber layer and a bead filler made of a vulcanized rubber composition comprising a natural rubber as a rubber component and having a difference between a dynamic tensile storage modulus E at 180 C. (A) and a dynamic tensile storage modulus E at 25 C. (B) {E(A)E(B)} of 2.0 MPa or more, the dynamic tensile storage moduli being measured under conditions of an initial tensile strain of 5%, a dynamic tensile strain of 1%, and a frequency of 52 Hz, and provides the tire excellent in achieving both the riding comfort in normal running and the durability in Run-flat running.

A modified liquid diene rubber (A) has a functional group (a) derived from an acid anhydride, and satisfies all the requirements (I) to (III) below: (I) The functional group equivalent weight of the functional groups (a) is in the range of 400 to 3,500 g/eq. (II) The polystyrene-equivalent number average molecular weight (Mn) measured by gel permeation chromatography (GPC) is in the range of 5,000 to 20,000. (III) The melt viscosity at 38 C. is not less than 3 Pa.Math.s and X (K) is not less than 6100 K wherein X is the slope of a linear line passing through two points in a graph in which the two points are values of melt viscosity (Pa.Math.s) at 38 C. and 60 C. measured with a Brookfield viscometer which are plotted as Ln[/(Pa.Math.s)] on ordinate versus 1/T (K.sup.1) on abscissa (with the proviso that T is temperature (K)).

A heavy-duty tire includes a tread part formed such that the tread part includes a crown profile including tire equator, and a pair of shoulder profiles extending from outer sides of the crown profile to tread edges. In a tire cross section including tire rotation axis in 5% internal pressure state in which the tire is mounted to a normal rim, filled with air at internal pressure of 5% of normal internal pressure and loaded with no load, each of the crown and shoulder profiles has an arc shape convex toward tire radial direction outer side such that ratio Rc/Rs of curvature radius Re of the crown profile to curvature radius Rs of each shoulder profile is 7.0 or more, and a tire axial direction distance from the equator to a connecting point between the crown profile and each shoulder profile is 0.70 or more times a tread half width.

The present invention relates to a rubber composition which makes it possible to achieve both of a riding comfort during normal running and durability during run flat running in a run flat tire. The rubber composition is a rubber composition containing a rubber component, a filler, a vulcanizing agent, and a vulcanization accelerator, wherein the rubber component contains 50% by mass or more of a modified conjugated diene-based rubber; the filler contains a carbon black; and the vulcanization accelerator contains a thiuram-based vulcanization accelerator, the carbon black being contained in an amount of 40 to 60 parts by mass, and the thiuram-based vulcanization accelerator being contained in an amount of 2.6 to 5.5 parts by mass based on 100 parts by mass of the rubber component.

A bead member for a tire, including: a bead wire; a first bead filler that is in contact with the bead wire directly or via another layer and is arranged in a region including at least a region at an outer side of the bead wire in a tire radial direction; and a second bead filler that is in contact with the first bead filler directly or via another layer and is arranged in a region including at least a region at an outer side of the first bead filler in the tire radial direction, the first bead filler including a resin A, the second bead filler including a resin B, and the resin B having a melting point higher than that of the resin A.

Metallated aminosilane compounds for use as functional initiators in anionic polymerizations and processes for producing an aminosilane-functionalized polymer using the metallated aminosilane compounds to initiate anionic polymerization of at least one type of anionically polymerizable monomer. Preferred use of the metallated aminosilane compounds results in rubber compositions for use in tires comprising an aminosilane functionalized polymer.

The present invention has as its object the provision of a polymer composition from which a rubber elastic body having high strength is obtained and in which excellent processability is achieved, and a tire having excellent strength. The polymer composition according to the present invention includes: a polymer (A) having a 1,2-polybutadiene chain (provided that a polymer falling within the definition for the below-described polymer (B) is excluded); and a polymer (B) having a structural unit derived from a conjugated diene compound and a structural unit derived from an aromatic vinyl compound, in which the structural unit derived from a conjugated diene compound contains a structural unit derived from butadiene, and the following mathematical formula (i) is satisfied when the composition ratios of a structural unit represented by the following chemical formula (1), a structural unit represented by the following chemical formula (2), a structural unit represented by the following chemical formula (3) and a structural unit represented by the following chemical formula (4) are p mol %, q mol %, r mol % and s mol %, respectively.

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0.70[(p+0.5r)/(p+q+0.5r+s)]0.99Mathematical Formula (i)