Sumitomo Rubber Industries Limited

Shin-etsu Chemical Co., Ltd.

Ryota Kitago

Hiroyuki Kishimoto

Ryo Mashita

Soh Ishino

Rie Yasuda

Ryuichi Tokimune

Yuuki Kawana

Takayuki Hattori

Munenao Hirokami

Takao Wada

Yuka Yokoyama

Tetsuro Yamada

Takayuki Nagase

Daisuke Sato

Shogo Hirao

Masanobu Nakamura

Tsuyoshi Tsuchida

Yuhei Yamashiro

Masaki Oshimo

Kazuya Torita

Yasumasa Bito

Ayuko Yamana

The purpose is to provide rubber compositions and pneumatic tires which have reduced changes in tan δ peak temperature over time. The present invention relates to rubber compositions containing at least one copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound, the rubber compositions having a heat aging resistance index defined by equation (1) of 0.45 or less.

Rubber composition and pneumatic tire

The purpose is to provide rubber compositions and pneumatic tires which have reduced changes in hardness over time. The present invention relates to a rubber composition containing a copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound, the rubber composition having a heat aging resistance index defined by equation (1) of 10 or less.

The purpose is to provide rubber compositions and pneumatic tires which have reduced changes in complex modulus E* over time. The present invention relates to rubber compositions containing at least one copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound, the rubber compositions having a heat aging resistance index defined by equation (1) of 27 or less.

The purpose is to provide rubber compositions and pneumatic tires which have reduced changes in tan δ over time. The present invention relates to rubber compositions containing at least one copolymer obtained by copolymerizing an aromatic vinyl compound and a conjugated diene compound, the rubber compositions having a heat aging resistance index defined by equation (1) of 2.0 or less.

Provided are a method for manufacturing a rubber composition for a tire and a method for manufacturing a tire including this manufacturing method for the rubber composition in the present invention, which are characterized by including the steps of: starting to knead a rubber component, a sulfur donor, and a sulfur atom-containing vulcanization accelerator together before kneading the rubber component with a filler; and then adding a filler to an obtained kneaded product and performing kneading at a kneading temperature of 120&#xb0; C. or higher. According to the manufacturing methods of the present invention, a rubber composition for a tire and a tire which have good fracture property can be manufactured.

Method for manufacturing rubber composition for tire and method for manufacturing tire

A pneumatic tire includes bead cores, a carcass ply, an inner liner and the tread, and the crosslinked rubber composition, of the present invention, wherein the tread and the crosslinked rubber composition have a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5 or less at elongation by an applied stress of 3.0 MPa and a ratio of 40% by mass or more of a component having a weight-average molecular weight of not less than 1,000,000 in a molecular weight distribution measured by gel permeation chromatography are excellent in abrasion resistance.

Pneumatic tire and crosslinked rubber composition

The pneumatic tire of the present invention characterized by comprising: bead cores, a carcass ply, an inner liner and a tread having a volume of the low density region of 35% or more, at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5% or less at elongation by an applied stress of 3.0 MPa and a glass transition temperature of &#x2212;20&#xb0; C. or lower, and the crosslinked rubber composition of the present invention having a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5 or less at elongation by an applied stress of 3.0 MPa and a glass transition temperature of &#x2212;20&#xb0; C. or lower are excellent in abrasion resistance.

A pneumatic tire includes bead cores, a carcass ply, an inner liner, and a tread having a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5% or less at elongation by an applied stress of 3.0 MPa and a hardness of 65 or more and the crosslinked rubber composition of the present invention having a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5 or less at elongation by an applied stress of 3.0 MPa and a hardness of 65 or more are excellent in abrasion resistance.

The pneumatic tire characterized by comprising the tread and the crosslinked rubber composition, of the present invention, wherein the tread and the crosslinked rubber composition comprise two or more kinds of rubber components and a filler and have a volume of the low density region of 35% or more, a volume of the void portion of 7.5 or less and a filler distribution D represented by the following formula (I) of 2.0 or less are excellent in abrasion resistance.=()/()&#x2003;&#x2003;(I) In the formula (I),

The pneumatic tire of the present invention characterized by comprising: bead cores, a carcass ply, an inner liner disposed at an inner side than the carcass ply in a direction of a tire diameter, and a tread disposed at an outer side than the carcass ply in a direction of a tire diameter and having a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5% or less at elongation by an applied stress of 3.0 MPa and a filler dispersibility index &#x394;G* shown by the following equation (I) of 3 or less and the crosslinked rubber composition having a volume of the low density region of 35% or more at elongation by an applied stress of 1.5 MPa, a volume of the void portion of 7.5 or less at elongation by an applied stress of 3.0 MPa and a filler dispersibility index &#x394;G* shown by the following equation (I) of 3 or less are excellent in abrasion resistance.&#x394;*=(*(4%)&#x2212;*(256%))/*(256%)&#x2003;&#x2003;(I)In the equation (I), G* (n %) indicates a shear modulus when an n % strain is applied.

The present invention provides rubber compositions that can achieve both abrasion resistance and low heat build-up properties, and pneumatic tires including such rubber compositions. The present invention relates to a rubber composition containing one or more carbon blacks, at least one of which is produced from a feedstock oil that has a BMCI value of not greater than 150 and an aliphatic hydrocarbon content of not less than 30% by mass.

Provided are a rubber composition for tires which achieves both abrasion resistance and processability while maintaining fuel economy, and a pneumatic tire including the rubber composition. A rubber composition for tires, containing an organosilicon compound represented by the average compositional formula (I) below having a ratio of the number of sulfur atoms to the number of silicon atoms of 1.0 to 1.5, wherein x represents the average number of sulfur atoms; m represents an integer of 6 to 12; and Rto Rare the same or different and each represent a C1-C6 alkyl or alkoxy group, at least one of Rto Rand at least one of Rto Rare the alkoxy groups, and two or more of the alkyl or alkoxy groups for Rto Rmay be joined to form a ring.

Rubber composition for tires and pneumatic tire

The present invention aims to provide pneumatic tires that can achieve both abrasion resistance and low heat build-up properties. The present invention relates to a pneumatic tire including a tread formed from a rubber composition, the rubber composition containing: a rubber component including an isoprene-based rubber and a high-cis polybutadiene rubber having a cis content of 90% by mass or more; one or more types of carbon black; and sulfur, at least one of the one or more types of carbon black being produced from a feedstock oil that has a BMCI value of 150 or less and an aliphatic hydrocarbon content of 30% by mass or more, the BMCI value being calculated from the average boiling point T (&#xb0; C.) and the specific gravity D (60/60&#xb0; F.) relative to water at 60&#xb0; F. according to the equation below,=48,640/(+273)+473.7&#x2212;456.8.

A method for manufacturing a rubber composition includes kneading a rubber component, an inorganic filler and a thioester-based silane coupling agent, and adding a vulcanizing agent and one or more compounds selected from the group of an imide compound and an N-oxyl compound to a mixture of the rubber component, the inorganic filler, and the thioester-based silane coupling agent such that the vulcanizing agent and the imide compound and/or the N-oxyl compound are kneaded with the mixture including the rubber component, the inorganic filler, and the thioester-based silane coupling agent.

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Kobe, Japan

Ryota Kitago