Abstract: A pneumatic tire comprising a tread composed of a rubber composition containing 30 to 120 parts by mass of silica having a BET specific surface area of 180 to 280 m2/g based on 100 parts by mass of a rubber component, wherein, under a normal state with no load where the pneumatic tire is mounted with a normal rim and filled with a normal internal pressure, a grounding surface shape in which a normal load is applied and the tread is pressed against a plane surface satisfies the following equation (1): 0.95?SL0/SL80?1.6 (wherein, SL0 is a ground contact length in a circumferential direction of the tire on a tire equator, and SL80 is a ground contact length in a circumferential direction of the tire on a position away from the tire equator by a distance in a tire axial direction of 80% of a tread grounding half width.

Abstract: There is provided a pneumatic tire having improved wet grip performance and fuel efficiency in a good balance. The pneumatic tire is provided with a tread composed of a rubber composition comprising not less than 0.5 part by mass of silica and not less than 5 parts by mass of a resin based on 100 parts by mass of a rubber component comprising 40 to 100% by mass of a styrene-butadiene rubber and 0 to 60% by mass of a butadiene rubber, wherein an adhesive force of the rubber composition measured by the specified adhesion test method is not less than 300 when an adhesive force of a reference rubber composition wherein the whole amount of resin has been replaced by oil is assumed to be 100, and a ratio of a loss tangent tan ?0° C. at 0° C. of the rubber composition to a loss tangent tan ?70° C. at 70° C. of the rubber composition (tan ?0° C./tan ?70° C. is from 3.0 to 10.

Abstract: A pneumatic tire comprising a tread composed of a rubber composition, the rubber composition containing 30 to 120 parts by mass of silica having a BET specific surface area of 180 to 280 m2/g based on 100 parts by mass of a rubber component, wherein, under a normal state with no load where the pneumatic tire is mounted with a normal rim and filled with a normal internal pressure, a grounding surface shape in which a normal load is applied and the tread is pressed against a plane surface satisfies the following equation (1): 0.95?SL0/SL80?1.6 (wherein, SL0 is a ground contact length in a circumferential direction of the tire on a tire equator, and SL80 is a ground contact length in a circumferential direction of the tire on a position away from the tire equator by a distance in a tire axial direction of 80% of a tread grounding half width.

Abstract: Provided are a polymer ready for introduction into a kneading machine which is milled with good milling efficiency in a kneading machine and which provides a kneaded mixture with excellent filler dispersion, and a rubber composition and a pneumatic tire containing the polymer. The present invention relates to a polymer ready for introduction into a kneading machine, excluding natural rubber, the polymer having a temperature within the range of ?20° C. to 80° C. and satisfying the following formula (I): (Tip clearance d of kneading machine)3?(Volume V of polymer ready for introduction into kneading machine)?2.0×104 cm3??(I).

Abstract: According to the process for preparing a vulcanized rubber composition of the invention comprising (a) a step of preparing a master batch comprising a modified conjugated diene polymer and silica, (b) a step of preparing a master batch comprising an isoprene rubber and silica, (c) a step of kneading the master batch obtained in (a) and the master batch obtained in (b), and (d) a step of vulcanizing a kneaded product obtained in (c), wherein the obtained vulcanized rubber composition comprises a phase A comprising a modified conjugated diene polymer and a phase B comprising an isoprene rubber, which are incompatible with each other, an abundance ratio ? of silica in the phase A satisfies 0.5???0.9 (Relation 1), and a proportion ? of the modified conjugated diene polymer satisfies 0.4???0.

Abstract: Provided are a polymer ready for introduction into a kneading machine which is milled with good milling efficiency in a kneading machine and which provides a kneaded mixture with excellent filler dispersion, and a rubber composition and a pneumatic tire containing the polymer. The present invention relates to a polymer ready for introduction into a kneading machine, excluding natural rubber, the polymer having a temperature within the range of ?20° C. to 80° C. and satisfying the following formula (I): (Tip clearance d of kneading machine)3?(Volume V of polymer ready for introduction into kneading machine)?2.0×104 cm3??(I).

Abstract: Provided by the present invention are a rubber composition for studless winter tires capable of improving performance on snow and ice while maintaining good abrasion resistance, and a studless winter tire including the rubber composition. The present invention relates to a rubber composition for studless winter tires containing a rubber component and bionanofibers, the bionanofibers having an average fiber diameter of 0.1 ?m or less, the rubber component having a combined amount of natural rubber and polybutadiene rubber of 30% to 100% by mass based on 100% by mass of the rubber component, the rubber composition containing the bionanofibers in an amount of 1 to 10 parts by mass relative to 100 parts by mass of the rubber component.

Abstract: There is provided a pneumatic tire having improved wet grip performance and fuel efficiency in a good balance. The pneumatic tire is provided with a tread composed of a rubber composition comprising not less than 0.5 part by mass of silica and 5 to 50 parts by mass of a resin having a melt viscosity (150° C.) of 12000 to 15000 mPa·s based on 100 parts by mass of a rubber component. The rubber component comprises 40 to 100% by mass of a styrene-butadiene rubber and 0 to 60% by mass of a butadiene rubber. The resin is selected from the group consisting of a terpene phenol resin, a phenol resin and an alkylphenol resin.

Abstract: A purpose of the present invention is to provide a tire assuring that clogging of snow and sticking of snow are inhibited, particularly a tire assuring that clogging of snow and sticking of snow can be inhibited and having good performance on ice and snow and abrasion resistance without depending on the tread pattern form while maintaining wet grip performance and abrasion resistance. The tire is composed of a rubber composition which comprises a rubber component comprising a modified butadiene rubber and silica and has a pure water contact angle of from 125° to 140°.

Abstract: A studless winter tire that has enhanced performance on ice and snow both initially and after degradation while maintaining good abrasion resistance is provided. The studless winter tire includes: a cap tread formed from a rubber composition A; and a base tread formed from a rubber composition B. The studless winter tire satisfies the following formulas (1) and (2): (1) a×c/100<b×d/100; and (2) a?8, where a represents the softener content (% by mass) based on 100% by mass of the rubber composition A; b represents the softener content (% by mass) based on 100% by mass of the rubber composition B; c represents the percentage by mass (% by mass) of the cap tread based on the entire tread; and d represents the percentage by mass (% by mass) of the base tread based on the entire tread.

Abstract: Provided are a polymer ready for introduction into a kneading machine which is milled with good milling efficiency in a kneading machine and which provides a kneaded mixture with excellent filler dispersion, and a rubber composition and a pneumatic tire containing the polymer. The present invention relates to a polymer ready for introduction into a kneading machine, excluding natural rubber, the polymer having a temperature within the range of ?20° C. to 80° C. and satisfying the following formula (I): (Tip clearance d of kneading machine)3?(Volume V of polymer ready for introduction into kneading machine)?2.0×104 cm3 ?? (I).

Abstract: Provided are rubber compositions for tires capable of providing tire components and pneumatic tires that have the same level of fuel efficiency and wet grip performance (particularly, wet grip performance) as those of tire components and pneumatic tires containing conventional synthetic rubber, while satisfying the requirements for a sound material-cycle society. The present invention relates to rubber compositions for tires containing a biomass-derived rubber polymerized from an aromatic vinyl compound and a diene, the biomass-derived rubber having a pMC (percent modern carbon) measured in accordance with ASTM D 6866-10 of 1% or higher.

Abstract: According to the process for preparing a vulcanized rubber composition of the invention comprising (a) a step of preparing a master batch comprising a butadiene rubber and silica, (b) a step of preparing a master batch comprising an isoprene rubber and silica, (c) a step of kneading the master batch obtained in (a) and the master batch obtained in (b), and (d) a step of vulcanizing a kneaded product obtained in (c), wherein the obtained vulcanized rubber composition comprises a BR phase and a IR phase, which are incompatible with each other, a predetermined abundance ratio ? of silica in the BR phase satisfies 0.3???0.7 (Relation 1), and a proportion ? of the butadiene rubber satisfies 0.4???0.8 (Relation 2) it is possible to improve performance on ice and abrasion resistance and to provide a vulcanized rubber composition having excellent performance on ice and abrasion resistance, and a studless tire with a tread made using the same.

Abstract: According to the process for preparing a vulcanized rubber composition of the invention comprising (a) a step of preparing a master batch comprising a butadiene rubber and silica, (b) a step of preparing a master batch comprising an isoprene rubber and silica, (c) a step of kneading the master batch obtained in (a) and the master batch obtained in (b), and (d) a step of vulcanizing a kneaded product obtained in (c), wherein the obtained vulcanized rubber composition has a BR phase and a IR phase which are incompatible with each other and comprises a predetermined amount of a terpene resin, a predetermined abundance ratio ? of silica in the BR phase satisfies 0.3???0.7 (Relation 1), and a proportion ? of the butadiene rubber satisfies 0.4???0.

Abstract: There is provided a pneumatic tire having improved wet grip performance and fuel efficiency in a good balance. The pneumatic tire is provided with a tread composed of a rubber composition comprising not less than 0.5 part by mass of silica and not less than 5 parts by mass of a resin based on 100 parts by mass of a rubber component comprising 40 to 100% by mass of a styrene-butadiene rubber and 0 to 60% by mass of a butadiene rubber, wherein an adhesive force of the rubber composition measured by the specified adhesion test method is not less than 300 when an adhesive force of a reference rubber composition wherein the whole amount of resin has been replaced by oil is assumed to be 100, and a ratio of a loss tangent tan ?0° C. at 0° C. of the rubber composition to a loss tangent tan ?70° C. at 70° C. of the rubber composition (tan ?0° C./tan ?70° C. is from 3.0 to 10.

Abstract: According to the process for preparing a vulcanized rubber composition of the invention comprising (a) a step of preparing a master batch comprising a modified conjugated diene polymer and silica, (b) a step of preparing a master batch comprising an isoprene rubber and silica, (c) a step of kneading the master batch obtained in (a) and the master batch obtained in (b), and (d) a step of vulcanizing a kneaded product obtained in (c), wherein the obtained vulcanized rubber composition comprises a phase A comprising a modified conjugated diene polymer and a phase B comprising an isoprene rubber, which are incompatible with each other, an abundance ratio ? of silica in the phase A satisfies 0.5???0.9 (Relation 1), and a proportion ? of the modified conjugated diene polymer satisfies 0.4???0.

Abstract: Provided are: a rubber composition for studless winter tires, achieving balanced improvement in performance on ice and snow, wet grip performance, and abrasion resistance; and a studless winter tire including a tread formed from the same. The rubber composition for studless winter tires includes: a rubber component including NR and BR; an aromatic oil; silica; and carbon black, wherein the combined amount of NR and BR is 30 mass % or more per 100 mass % of the rubber component; the amount of aromatic oil is 12-85 parts by mass per 100 parts by mass of the rubber component; the silica content is 45 mass % or more per 100 mass % in total of silica and carbon black; the silica includes at least one silica (1) with an N2SA of 100 m2/g or less and at least one silica (2) with an N2SA of 180 m2/g or more; the combined amount of silicas (1) and (2) is 30-150 parts by mass per 100 parts by mass of the rubber component; and the amounts of silicas (1) and (2) satisfy: [Amount of silica (1)]×0.

Abstract: The present invention provides rubber compositions for tires capable of providing tire components and pneumatic tires having low-temperature properties and abrasion resistance that are equivalent to those of tire components and pneumatic tires formed from conventional synthetic rubber, respectively, while meeting the demand for a sound material-cycle society. The present invention relates to rubber compositions for tires containing a biomass-derived rubber obtained by polymerizing a biomass-derived monomer component, the biomass-derived rubber having a pMC (percent modern carbon) value of 1% or greater as determined in conformity with ASTM D6866-10, and having a Tg (glass transition temperature) value of ?120° C. to ?80° C.

Abstract: A purpose of the present invention is to provide a tire assuring that clogging of snow and sticking of snow are inhibited, particularly a tire assuring that clogging of snow and sticking of snow can be inhibited and having good performance on ice and snow and abrasion resistance without depending on the tread pattern form while maintaining wet grip performance and abrasion resistance. The tire is composed of a rubber composition which comprises a rubber component comprising a modified butadiene rubber and silica and has a pure water contact angle of from 125° to 140°.

Abstract: Provided by the present invention are a rubber composition for studless winter tires capable of improving performance on snow and ice while maintaining good abrasion resistance, and a studless winter tire including the rubber composition. The present invention relates to a rubber composition for studless winter tires containing a rubber component and bionanofibers, the bionanofibers having an average fiber diameter of 0.1 ?m or less, the rubber component having a combined amount of natural rubber and polybutadiene rubber of 30% to 100% by mass based on 100% by mass of the rubber component, the rubber composition containing the bionanofibers in an amount of 1 to 10 parts by mass relative to 100 parts by mass of the rubber component.