A pneumatic tire includes: a rubber member A containing a rubber component containing 70 mass % to 100 mass % of a hydrogenated copolymer, sulfur, and a triazine-thiol compound; and a rubber member B containing sulfur and a rubber component containing a diene rubber. The hydrogenated copolymer is obtained by hydrogenating an aromatic vinyl-conjugated diene copolymer, has a weight average molecular weight of 300,000 or more as measured by gel permeation chromatography, and has a hydrogenation rate of a conjugated diene moiety of 80 mol % or more, the rubber member A and the rubber member B are in contact with each other at an interface, and a content of the triazine-thiol compound is 0.1 parts by mass to 5 parts by mass with respect to 100 parts by mass of the rubber component in the rubber member A.

Disclosed herein are a terminal-functionalized polymer, rubber compositions containing the polymer, and related processes for preparing the polymer. The functionalizing compound used to prepare the terminal-functionalized polymer has a specified formula which includes a silicon atom and a moiety containing at least two carbon-carbon double bonds in a conjugated configuration.

Disclosed herein are a terminal-functionalized polymer, rubber compositions containing the polymer, and related processes for preparing the polymer. The functionalizing compound used to prepare the terminal-functionalized polymer has a specified formula which includes a silicon atom and a moiety containing at least two carbon-carbon double bonds in a conjugated configuration.

Embodiments of the present disclosure are directed to functionalized copolymers produced by copolymerization of at least one conjugated diolefin monomer and at least one vinyl monomer, the functionalized copolymer comprising at least one functional group having silica reactive moieties, wherein the functionalized copolymer has a degree of hydrogenation of 75% to 98 mol % as measured using proton nuclear magnetic resonance spectroscopy (.sup.1H NMR).

The invention relates to an elastomeric polymer composition and its preparation. The polymer composition includes, in combination, a single terminally modified conjugated diene (co)polymer and a dual terminally modified conjugated diene (co)polymer. The polymer composition is useful in the preparation of a vulcanized and, thus, crosslinked elastomeric composition having relatively low hysteresis loss, good grip and low heat build-up properties.

There is disclosed a modified conjugated diene polymer including a structural unit derived from a compound represented by formula (1), and a structural unit derived from a conjugated diene.

##STR00001##

When n is 0, at least two of R.sup.11, R.sup.12, R.sup.13, R.sup.16, R.sup.17 and R.sup.18 are substituted amino groups, and at least one is a hydroxy group or hydrocarbyloxy group.

A method for preparing a functionalized polymer, the method comprising the steps of: (i) polymerizing monomer to form a reactive polymer, and (ii) reacting the reactive polymer with an imine compound containing a heterocyclic group and a hydrocarbyloxy-substituted or silyloxy-substituted aryl group.

A method for preparing a functionalized polymer, the method comprising the steps of: (i) polymerizing monomer to form a reactive polymer, and (ii) reacting the reactive polymer with an imine compound containing a heterocyclic group and a hydrocarbyloxy-substituted or silyloxy-substituted aryl group.

The present invention provides a rubber composition that can enhance the fuel economy, wet-grip performance, abrasion resistance, and kneading processability in a balanced manner, and a pneumatic tire using this rubber composition. The present invention relates to a rubber composition that contains a rubber component and silica, wherein the rubber component contains, based on 100% by mass of the rubber component, 10 to 70% by mass of a high-cis polybutadiene having a cis content of 95% by mass or more and satisfying the following requirements (A) to (C): (A) a Mooney viscosity (ML) of 40 to 49; (B) a molecular weight distribution (weight-average molecular weight (Mw)/number-average molecular weight (Mn)) of 3.0 to 3.9; and (C) an index (n-value in Expression (1) below) of velocity dependence of Mooney viscosity of 2.3 to 3.0, and 30 to 90% by mass of a conjugated diene polymer containing a constituent unit based on a conjugated diene and a constituent unit represented by formula (I) below, and an amount of the silica is 5 to 150 parts by mass per 100 parts by mass of the rubber component,
log(ML)=log(K)+n.sup.−1×log(RS)  (Expression 1)
wherein RS indicates the number of revolutions per minute of a rotor, K indicates an arbitrary number, and ML indicates a Mooney viscosity, ##STR00001##

The present invention provides a rubber composition that can enhance the fuel economy, wet-grip performance, abrasion resistance, and kneading processability in a balanced manner, and a pneumatic tire using this rubber composition. The present invention relates to a rubber composition that contains a rubber component and silica, wherein the rubber component contains, based on 100% by mass of the rubber component, 10 to 70% by mass of a high-cis polybutadiene having a cis content of 95% by mass or more and satisfying the following requirements (A) to (C): (A) a Mooney viscosity (ML) of 40 to 49; (B) a molecular weight distribution (weight-average molecular weight (Mw)/number-average molecular weight (Mn)) of 3.0 to 3.9; and (C) an index (n-value in Expression (1) below) of velocity dependence of Mooney viscosity of 2.3 to 3.0, and 30 to 90% by mass of a conjugated diene polymer containing a constituent unit based on a conjugated diene and a constituent unit represented by formula (I) below, and an amount of the silica is 5 to 150 parts by mass per 100 parts by mass of the rubber component,
log(ML)=log(K)+n.sup.−1×log(RS)  (Expression 1)
wherein RS indicates the number of revolutions per minute of a rotor, K indicates an arbitrary number, and ML indicates a Mooney viscosity, ##STR00001##