Asahi Kasei Kabushiki Kaisha

Asahi Kasei Chemicals Corporation

Bridgestone Corporation

Shinichi Sekikawa

Miki Kyo

Junichi Yoshida

Takaaki Matsuda

Kenta Hisamura

Yoshifumi Araki

Hiromi Nakafutami

Shogo Sumitani

Takashi Sato

Jun Yonezawa

Ryoko Fukuoka

Shuri Tobo

Syogo Sumitani

Takaaki Ushio

A conjugated diene-based polymer of the present invention has a branch number (Bn) measured by viscosity detector-equipped GPC-light scattering measurement of 8 or more, has a change (ΔT) of an oxidation onset temperature caused through application of a thermal load of 11.9° C. or less, and contains an aromatic vinyl compound monomer unit.

Conjugated diene-based polymer, branching agent, production method for conjugated diene-based polymer, oil extended conjugated diene-based polymer, rubber composition, and tire

The present invention provides a conjugated diene-based polymer composition excellent in rolling resistance, grip performance on a wet road surface, and abrasion resistance when formed into a tire. Also provided is a conjugated diene-based polymer composition containing: 10 to 90 parts by mass of a conjugated diene-based polymer (A) having a glass transition temperature of −20° C. or more; and 10 to 90 parts by mass of a conjugated diene-based polymer (B) having a glass transition temperature of −25° C. or less, wherein the conjugated diene-based polymer (A) has an absolute molecular weight, measured by viscosity detector-equipped GPC-light scattering measurement, of 40×10or more and 5000×10or less, and a branch number (Bn), measured by the viscosity detector-equipped GPC-light scattering measurement, of 8 or more.

Conjugated diene-based polymer composition and tire

A production method for a branched conjugated diene-based polymer, comprising:

Production method for branched conjugated diene-based polymer, production method for rubber composition, production method for tire, branched conjugated diene-based polymer, and branched conjugated diene-based polymer composition

A modified conjugated diene-based polymer, including a coupling polymer,

Modified conjugated diene-based polymer, rubber composition, and tire

A modified conjugated diene-based polymer containing:

Modified conjugated diene-based polymer and rubber composition thereof, and tire

The present invention provides a modified conjugated diene-based polymer having a weight-average molecular weight of 20&#xd7;10or more and 300&#xd7;10or less, in which the modified conjugated diene-based polymer having a molecular weight of 200&#xd7;10or more and 500&#xd7;10or less is comprised in an amount of 0.25% by mass or more and 30% by mass or less based on a total amount of the modified conjugated diene-based polymer, and a shrinking factor (g') is less than 0.64.

Modified conjugated diene-based polymer and production method therefor, rubber composition and tire

In a modified conjugated diene-based polymer, a ratio of a coupling polymer, obtained by gel permeation chromatography (GPC), is 70% by mass or more based on a total amount of the modified conjugated diene-based polymer, and a modification ratio obtained by adsorption GPC is 70% by mass or more based on a total amount of the modified conjugated diene-based polymer, and when Mooney viscosity ML(100&#xb0; C.) measured at 100&#xb0; C. is represented by ML and a weight average molecular weight obtained by GPC is represented by Mw, ML&#x2264;1.8 (Mw&#xd7;10)&#x2212;31.5, and Mooney viscosity ML(100&#xb0; C.) measured at 100&#xb0; C. is 30 to 150.

A method for producing a modified conjugated diene-based polymer having a good balance between the hysteresis loss properties and the wet skid resistance, practically sufficient abrasion resistance and breaking strength, and high processability when formed into a vulcanized product is provided. A method for producing a modified conjugated diene-based polymer, comprising: a polymerization step of polymerizing a conjugated diene compound, copolymerizing conjugated diene compounds, or copolymerizing a conjugated diene compound with an aromatic vinyl compound using an alkali metal compound or an alkaline earth metal compound as a polymerization initiator to obtain a conjugated diene-based polymer having an active end, and a modifying step of reacting a compound represented by following formula (1) with the active end of the conjugated diene-based copolymer. 

Method for producing modified conjugated diene-based polymer, modified conjugated diene-based polymer, and modified conjugated diene-based polymer composition

There is provided a modified conjugated diene-based polymer having a silyl group substituted with one or more alkoxy groups, and one or more nitrogen atoms on the chain ends of a conjugated diene-based polymer, the modified conjugated diene-based polymer being obtained by polymerizing a conjugated diene compound, or copolymerizing a conjugated diene compound with an aromatic vinyl compound, by using a polyfunctional anionic polymerization initiator prepared from a polyvinyl aromatic compound and an organolithium compound in a range of a molar ratio (the polyvinyl aromatic compound/the organolithium compound) of from 0.05 to 1.0, so as to obtain the conjugated diene-based polymer, and by reacting a living polymer end of the conjugated diene polymer with the compound having a silyl group substituted with two or more alkoxy groups, and one or more nitrogen atoms.

Modified conjugated diene-based polymer, method for producing the same, modified conjugated diene-based polymer composition, and tire

There are provided a modified conjugated diene-based polymer having a good balance between the hysteresis loss properties and the wet skid resistance, practically sufficient abrasion resistance and fracture strength, and high processability when formed into a vulcanized product, and a modified conjugated diene-based polymer composition. A method for producing a modified conjugated diene-based polymer, comprising: a polymerization step of polymerizing a conjugated diene compound or copolymerizing a conjugated diene compound with an aromatic vinyl compound using an alkali metal compound or an alkaline earth metal compound as a polymerization initiator to obtain a conjugated diene-based polymer having a reactive end, and a modifying step of reacting a compound having a specific structure with the reactive end of the conjugated diene-based polymer.

A hydrogenated block copolymer which comprises at least two polymer blocks A each mainly comprising an aromatic vinyl hydrocarbon compound monomer unit and at least two hydrogenated polymer blocks B each mainly comprising a butadiene monomer unit, at least 90% of the olefinically unsaturated double bonds in said polymer block mainly comprising a butadiene monomer unit before hydrogenation having been hydrogenated, wherein at least one of the block at the terminal of the hydrogenated block copolymer is the polymer block B, wherein the proportion of the terminal polymer blocks B in the hydrogenated block copolymer is at least 0.1 wt % but less than 9.1 wt %, wherein the proportion of the aromatic vinyl hydrocarbon compound in the hydrogenated block copolymer exceeds 10 wt % but less than 25 wt %, wherein the 1,2-bond content of the polymer blocks mainly comprising a butadiene monomer unit before hydrogenation is, on average, at least 62 mole % but less than 99 mol %, and wherein the difference &Dgr;Tc (Tc1&minus;Tc2) between the crystallization initiating temperature (Tc1) of the isotactic homopolypropylene and the crystallization initiating temperature (Tc2) of a mixture thereof with the hydrogenated block copolymer is at least 1.5&deg; C.

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Tokyo, Japan

Shinichi Sekikawa