Abstract: The present invention provides a rubber composition excellent in grip performance, durability of grip performance, and abrasion resistance. Also provided is a pneumatic tire formed from the rubber composition. The present invention relates to a rubber composition exhibiting a temperature dependence curve of tan 5 with a half-width defined by Equation (1) of 45 or less as measured at a strain of 0.1% and a frequency of 10 Hz, the rubber composition having a temperature dependence of hardness defined by Equation (2) of 4.3 or less, the temperature dependence curve having a peak temperature of 10° C. or lower, half-width=(temperature at half-peak height on high temperature side)?(temperature at half-peak height on low temperature side), ??Equation (1): temperature dependence of hardness=(hardness index at 0° C.)/(hardness index at 100° C.).

Abstract: A pneumatic tire produced by processing a rubber composition including a hydrogenated branched conjugated diene copolymer produced by copolymerizing a branched conjugated diene compound and a vinyl compound to form a branched conjugated diene copolymer and hydrogenating the branched conjugated diene copolymer. The branched conjugated diene compound is represented by formula (1), where R1 is an aliphatic hydrocarbon having 6 to 11 carbon atoms, the vinyl compound is represented by formula (3), where R4 is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 3 carbon atoms, an alicyclic hydrocarbon group having 3 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms, copolymerization ratio of the branched conjugated diene compound is 1 to 99% by weight, copolymerization ratio of the vinyl compound is 99 to 1% by weight, the branched conjugated diene compound is myrcene and/or farnesene, and the vinyl compound is styrene.

Abstract: A pneumatic tire produced by processing a rubber composition including a hydrogenated branched conjugated diene copolymer produced by copolymerizing a branched conjugated diene compound and a vinyl compound to form a branched conjugated diene copolymer and hydrogenating the branched conjugated diene copolymer. The branched conjugated diene compound is represented by formula (1), where R1 is an aliphatic hydrocarbon having 6 to 11 carbon atoms, the vinyl compound is represented by formula (3), where R4 is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 3 carbon atoms, an alicyclic hydrocarbon group having 3 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms, copolymerization ratio of the branched conjugated diene compound is 1 to 99% by weight, copolymerization ratio of the vinyl compound is 99 to 1% by weight, the branched conjugated diene compound is myrcene and/or farnesene, and the vinyl compound is styrene.

Abstract: Provided is a studless winter tire which provides good performance on ice and snow and good abrasion resistance, and suffers little change in hardness and little discoloration on the tire surface. The present invention relates to a studless winter tire including a tread formed from a rubber composition containing a predetermined amount of a farnesene resin obtained by polymerizing farnesene. The present invention relates to a studless winter tire including a tread formed from a rubber composition containing a predetermined amount of at least one myrcene resin selected from the group consisting of myrcene polymers with a Mw of 1,000-500,000, myrcene-butadiene copolymers with a Mw of 1,000-500,000, and myrcene-styrene copolymers with a Mw of 1,000-150,000; and a predetermined amount of a silica with an N2SA of 40-400 m2/g, the rubber component containing a predetermined amount of a high-cis polybutadiene with a cis content of 95% by mass or more.

Abstract: Provided is a studless winter tire which provides good performance on ice and snow and good abrasion resistance, and suffers little change in hardness and little discoloration on the tire surface. The present invention relates to a studless winter tire including a tread formed from a rubber composition containing a predetermined amount of a farnesene resin obtained by polymerizing farnesene. The present invention relates to a studless winter tire including a tread formed from a rubber composition containing a predetermined amount of at least one myrcene resin selected from the group consisting of myrcene polymers with a Mw of 1,000-500,000, myrcene-butadiene copolymers with a Mw of 1,000-500,000, and myrcene-styrene copolymers with a Mw of 1,000-150,000; and a predetermined amount of a silica with an N2SA of 40-400 m2/g, the rubber component containing a predetermined amount of a high-cis polybutadiene with a cis content of 95% by mass or more.

Abstract: The present invention provides a pneumatic tire including a tread formed from a rubber composition that can simultaneously highly improve initial grip performance and stable grip performance during the middle and late periods of running, and further can reduce the occurrence of blowing even during high-temperature running. The present invention relates to a pneumatic tire including a tread, the tread being formed from a rubber composition containing a diene rubber, the rubber composition further containing a hydrogenated terpene aromatic resin obtained by hydrogenation of the double bonds of a terpene aromatic resin, the hydrogenated terpene aromatic resin having a degree of hydrogenation of double bonds of 5-100%, a hydroxyl value of 20 mg KOH/g or less, and a softening point of 116-180° C., the hydrogenated terpene aromatic resin being present in an amount of 1-50 parts by mass per 100 parts by mass of the diene rubber.

Abstract: An object of the present invention is to provide a rubber composition for tire that is excellent in abrasion resistance, initial grip performance and stability of grip performance while maintaining processability. The rubber composition for tire comprises a diene rubber component, a hydrocarbon resin containing a component unit derived from a monomer component having a heteroatom or a hydrogenated product thereof (resin A) and a hydrocarbon resin that does not contain a component unit derived from a monomer component having a heteroatom or a hydrogenated product thereof (resin B), wherein a content ratio (mass ratio) of the resin B to the resin A is 0.1 to 50.

Abstract: Provided are: a rubber composition for treads having high grip performance, abrasion resistance, and tensile properties and capable of reducing the occurrence of blowing even during high-temperature running although it is a high softener content composition incorporating at least a certain amount of a softener with a rubber component including diene rubber; and a pneumatic tire including a tread formed from the rubber composition for treads. Included is a rubber composition for treads containing: a diene rubber including styrene-butadiene rubber; at least one softener selected from the group consisting of low temperature plasticizers, process oils, and resins having a softening point of 160° C. or lower; zinc dithiophosphate; and sulfur, wherein, per 100 parts by mass of the diene rubber, there are 40 parts by mass or more of the softener, 0.2-15 parts by mass of the zinc dithiophosphate, and less than 2.5 parts by mass of zinc oxide.

Abstract: An object of the present invention is to provide a rubber composition for tire that is excellent in abrasion resistance, initial grip performance and stability of grip performance while maintaining processability. The rubber composition for tire comprises a diene rubber component, a hydrocarbon resin containing a component unit derived from a monomer component having a heteroatom or a hydrogenated product thereof (resin A) and a hydrocarbon resin that does not contain a component unit derived from a monomer component having a heteroatom or a hydrogenated product thereof (resin B), wherein a content ratio (mass ratio) of the resin B to the resin A is 0.1 to 50.

Abstract: Provided are a polymer composite capable of imparting good processability to a rubber composition and, further, achieving balanced improvements in initial grip performance, grip performance stability, and abrasion resistance; and a method for producing the polymer composite. Also provided are a rubber composition and a pneumatic tire that are formed from the polymer composite. The present invention relates to a polymer composite obtained by mixing a resinous organic compound having a weight average molecular weight of 250 or more and a polymer having a weight average molecular weight of 3,000 or more, the polymer being synthesized by polymerizing a conjugated diene monomer that is a conjugated diene-containing monomer.

Abstract: There is provided a branched conjugated diene copolymer prepared by copolymerizing 1 to 99% by weight of a branched conjugated diene compound (1): wherein R1 is an aliphatic hydrocarbon having 6 to 11 carbon atoms, and 99 to 1% by weight of a conjugated diene compound (2): wherein R2 and R3 are the same or different and each is a hydrogen atom, or the like. The branched conjugated diene copolymer is useful as a rubber component of a rubber composition for a tire enhancing both of abrasion resistance and grip performance to a high level and exhibiting excellent processability.

Abstract: There is provided a branched conjugated diene copolymer prepared by copolymerizing 1 to 99% by weight of a branched conjugated diene compound (1): wherein R1 is an aliphatic hydrocarbon having 6 to 11 carbon atoms, less than 99% by weight of a conjugated diene compound (2): wherein R2 and R3 are the same or different and each is a hydrogen atom, or the like, and less than 99% by weight of a vinyl compound (3): wherein R4 is an aromatic hydrocarbon group having 6 to 10 carbon atoms, or the like. The branched conjugated diene copolymer is useful as a rubber component of a rubber composition for a tire enhancing both of abrasion resistance and grip performance to a high level and exhibiting excellent processability.

Abstract: The present invention provides a novel partially hydrogenated phenolic resin being prepared by selectively hydrogenating double bonds other than those on aromatic rings of a phenolic resin and having a hydrogenation ratio of the double bonds of from 30 to 100% and a hydroxyl value of from 30 to 500 mgKOH/g, a rubber composition comprising the resin and exhibiting excellent grip performance and abrasion resistance, and a pneumatic tire produced using the rubber composition.

Abstract: There is provided a process for preparing a branched conjugated diene polymer by copolymerizing 1 to 100% by weight of a branched conjugated diene compound (1) monomer: wherein R1 is an aliphatic hydrocarbon having 6 to 11 carbon atoms, with 99 to 0% by weight of a conjugated diene compound (2) monomer: wherein R2 and R3 are the same or different and each is a hydrogen atom, or the like, and/or 99 to 0% by weight of a vinyl compound (3) monomer: wherein R4 is an aliphatic hydrocarbon group having 6 to 10 carbon atoms, or the like, wherein the process comprises a step of polymerizing by adding a monomer solution successively into a catalyst solution. The branched conjugated diene polymer is useful as a rubber component for a tire for improving processability.

Abstract: There is provided a hydrogenated branched conjugated diene copolymer prepared by copolymerizing 1 to 99% by weight of a branched conjugated diene compound (1): wherein R1 is an aliphatic hydrocarbon having 6 to 11 carbon atoms, 99 to 0% by weight of a conjugated diene compound (2): wherein R2 and R3 are the same or different and each is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 3 carbon atoms or a halogen atom, and/or 99 to 0% by weight of a vinyl compound (3): wherein R4 is a hydrogen atom, an aliphatic hydrocarbon group having 1 to 3 carbon atoms, an alicyclic hydrocarbon group having 3 to 8 carbon atoms, or an aromatic hydrocarbon group having 6 to 10 carbon atoms, and then hydrogenating the resulting copolymer.

Abstract: The present invention relates to a branched conjugated diene copolymer which is useful for preparing a rubber composition, having high uniformity of a temperature dependence curve of a viscoelasticity tan ?, for a tire, a rubber composition comprising the copolymer, and a pneumatic tire produced using the rubber composition for a tire. The branched conjugated diene copolymer is composed of monomer components comprising a branched conjugated diene compound represented by a general formula (1): wherein R1 represents an aliphatic hydrocarbon group having 6 to 11 carbon atoms, and an aromatic vinyl compound represented by a general formula (2): wherein R2 represents an aromatic hydrocarbon group having 6 to 10 carbon atoms, and R5 represents a hydrogen atom or the like, and a copolymerization ratio (m) of the aromatic vinyl compound (2) is 45% by mass or more.

Abstract: There is provided a branched conjugated diene copolymer prepared by copolymerizing 1 to 99% by weight of a branched conjugated diene compound (1): wherein R1 is an aliphatic hydrocarbon having 6 to 11 carbon atoms, and 99 to 1% by weight of a conjugated diene compound (2): wherein R2 and R3 are the same or different and each is a hydrogen atom, or the like. The branched conjugated diene copolymer is useful as a rubber component of a rubber composition for a tire enhancing both of abrasion resistance and grip performance to a high level and exhibiting excellent processability.

Abstract: The present invention relates to a branched conjugated diene copolymer which is useful for preparing a rubber composition, having high uniformity of a temperature dependence curve of a viscoelasticity tan ?, for a tire, a rubber composition comprising the copolymer, and a pneumatic tire produced using the rubber composition for a tire. The branched conjugated diene copolymer is composed of monomer components comprising a branched conjugated diene compound represented by a general formula (1): wherein R1 represents an aliphatic hydrocarbon group having 6 to 11 carbon atoms, and an aromatic vinyl compound represented by a general formula (2): wherein R2 represents an aromatic hydrocarbon group having 6 to 10 carbon atoms, and R5 represents a hydrogen atom or the like, and a copolymerization ratio (m) of the aromatic vinyl compound (2) is 45% by mass or more.

Abstract: There is provided a branched conjugated diene copolymer prepared by copolymerizing 1 to 99% by weight of a branched conjugated diene compound (1): wherein R1 is an aliphatic hydrocarbon having 6 to 11 carbon atoms, less than 99% by weight of a conjugated diene compound (2): wherein R2 and R3 are the same or different and each is a hydrogen atom, or the like, and less than 99% by weight of a vinyl compound (3): wherein R4 is an aromatic hydrocarbon group having 6 to 10 carbon atoms, or the like. The branched conjugated diene copolymer is useful as a rubber component of a rubber composition for a tire enhancing both of abrasion resistance and grip performance to a high level and exhibiting excellent processability.

Abstract: Provided is a studless winter tire which provides good performance on ice and snow and good abrasion resistance, and suffers little change in hardness and little discoloration on the tire surface. The present invention relates to a studless winter tire including a tread formed from a rubber composition containing a predetermined amount of a farnesene resin obtained by polymerizing farnesene. The present invention relates to a studless winter tire including a tread formed from a rubber composition containing a predetermined amount of at least one myrcene resin selected from the group consisting of myrcene polymers with a Mw of 1,000-500,000, myrcene-butadiene copolymers with a Mw of 1,000-500,000, and myrcene-styrene copolymers with a Mw of 1,000-150,000; and a predetermined amount of a silica with an N2SA of 40-400 m2/g, the rubber component containing a predetermined amount of a high-cis polybutadiene with a cis content of 95% by mass or more.