Bridgestone Corporation

Jsr Corporation

Other

Junko Kurazumi

Yoichi Ozawa

Toshihiro Tadaki

Takuo Sone

Koji Masaki

Ryouji Tanaka

Kouichirou Tani

Takahiro Nakamura

Eiju Suzuki

Steven Luo

Kevin Michael McCauley

Mark W Smale

Timothy Leonard Tartamella

Kouji Masaki

Tetsuya Ohmura

A process for simply and inexpensively producing a conjugated diene polymer with a narrow molecular weight distribution and a high cis-bond content at a low cost is provided. The process comprises a polymerization step, wherein a conjugated diene polymer having a cis-1,4-bond content of 98.5 mass % or more and a ratio (Mw/Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn) measured by gel permeation chromatography of 2.5 or less is obtained by carrying out a polymerization reaction in conjugated diene compounds using a catalyst composition containing a rare earth element-containing compound or a reaction product of the rare earth element-containing compound with a Lewis base, an aluminoxane and/or organoaluminum compound, and an iodine-containing compound.

Process for producing conjugated diene polymer, conjugated diene polymer, and rubber composition

A rubber composition for tire sidewall which comprises a rubber component, which comprises polybutadiene rubber having a content of the cis-1,4-bond of 92% or greater and a content of the vinyl bond of 1.5% or smaller and natural rubber and/or at least one other diene-based synthetic rubber, and 10 to 70 parts by mass of carbon black having a specific surface area by nitrogen adsorption of 20 to 100 m/g per 100 parts by mass of the rubber component and does not comprise a softener having an aniline point of 50&#xb0; C. or lower and a tire using the rubber composition for sidewall. Excellent resistance to cut growth is obtained while sufficient workability is surely exhibited.

Rubber composition for tire sidewall and tire

This invention relates to a method for producing functionalized cis-1,4-polydienes having a combination of a high cis-1,4-linkage content and a high functionality, the resulting polymers and the vulcanized products containing the polymers. The functionalized cis-1,4-polydienes of the present invention are produced by a method comprising the steps of: (1) preparing a reactive polymer by polymerizing conjugated diene monomer with a lanthanide-based catalyst in the presence of less than 20% by weight of organic solvent based on the total weight of monomer, organic solvent, and resulting polymer, where the lanthanide-based catalyst is the combination of or reaction product of (a) a lanthanide compound, (b) an aluminoxane, (c) an organoaluminum compound other than an aluminoxane, and (d) a halogen-containing compound; and (2) contacting the reactive polymer with a functionalizing agent.

Method for producing functionalized cis-1,4-polydienes having high cis-1,4-linkage content and high functionality

The present invention provides a modified conjugated diene polymer that is prepared by polymerization of a conjugated diene compound using a catalyst containing a lanthanoid rare earth element compound in an organic solvent and then modifying the resulting polymer having an active organic metal site with a modifier, wherein the modification efficiency is not less than 15% and the cis-1,4 bond content in the conjugated diene moiety measured by Fourier transform infrared spectroscopy satisfies the relationship (I):cis-1,4 bond content&#x2267;98.00(%)&#x2003;&#x2003;(I),or the modification efficiency is not less than 75% and the cis-1,4 bond content in the conjugated diene moiety measured by Fourier transform infrared spectroscopy satisfies the relationship (II):94.00(%)&#x2266;cis-1,4 bond content&#x3c;98.00(%)&#x2003;&#x2003;(II).The invention further provides a rubber composition containing the modified conjugated diene polymer and giving a tire exhibiting low heat build-up, satisfactory failure characteristics, and high abrasion resistance, and a tire composed of the rubber composition and exhibiting these characteristics.

Modified conjugated diene copolymer, rubber compositions and tires

A process for producing a modified conjugated diene polymer includes subjecting an active terminal of a conjugated diene polymer having a vinyl content of less than 10% and a cis-1,4 bond content of 75% or more to a modification reaction with an alkoxysilane compound, and subjecting the alkoxysilane compound (residue) to a condensation reaction in an aqueous solution at a pH of 9 to 14 and a temperature of 85 to 180&#xb0; C. in the presence of a condensation accelerator including a compound containing titanium. The modified conjugated diene polymer exhibits low heat build-up and increased reinforcing properties when used for a rubber composition, and exhibits excellent wear resistance, mechanical characteristics, and processability.

Process for producing modified conjugated diene polymer, modified conjugated diene polymer obtained by the process, and rubber composition containing the same

This invention is concerned with a butadiene-based polymer having a high cis-1,4 bond content, a low vinyl bond content and a molecular weight distribution of a specified range, and more particularly a butadiene-based polymer having a 1,3-butadiene monomer unit, characterized in that a cis-1,4 bond content and a vinyl bond content in the 1,3-butadiene monomer unit as measured by a Fourier transform infrared spectroscopy (FT-IR) is not less than 98.0% and not more than 0.3%, respectively, and a ratio (Mw/Mn) of weight average molecular weight (Mw) to number average molecular weight (Mn) is 1.6-3.5.

Butadiene-based polymer and method of producing the same as well as rubber composition and tire using the same

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Kodaira, Japan

Junko Kurazumi