Zeon Corporation

Takeshi Sugimura

Yasuo Tsunogae

Shigetaka Hayano

Takeshi Karato

Tatsuo Sasajima

Shingo Okuno

Hidenori Yamagishi

Hiroyuki Nitadori

Kazuya Ito

Naoaki Kuramoto

Satoshi Anezaki

Yasuhisa Tsukahara

[Problem] To provide a cyclopentene ring-opening copolymer used in a rubber composition for tires having excellent wet grip performance and low heat buildup; and a method for producing the cyclopentene ring-opening copolymer. To further provide a rubber composition obtained by using the cyclopentene ring-opening copolymer. [Solution] This cyclopentene ring-opening copolymer comprises cyclopentene and a cyclic olefin containing an aromatic ring; the content of the aromatic ring with respect to the total weight of the copolymer is 10 to 40 wt %; and the weight average molecular weight (Mw) is 200,000 to 1,000,000. The cyclopentene ring-opening copolymer alternatively comprises cyclopentene and a norbornene compound; the weight ratio of cyclopentene-derived structural units to all repeating structural units in the copolymer is 40 to 90 wt %, and the weight ratio of norbornene compound-derived structural units is 10 to 60 wt %; and the weight average molecular weight (Mw) is 200,000 to 1,000,000.

Cyclopentene ring-opening copolymer, method for producing same, and rubber composition

A method of production of modified conjugated diene rubber includes causing an aromatic compound having three or more carbon atoms directly bonded to an aromatic ring in one molecule to react with an alkali metal atom so as to obtain an alkali metal-reacted aromatic compound; polymerizing a monomer at least containing a conjugated diene compound by using the alkali metal-reacted aromatic compound so as to obtain a conjugated diene rubber having an active end; causing the active end of the conjugated diene rubber having an active end to react with an activity control agent so as to obtain a conjugated diene rubber reacted with an activity control agent; and causing the active end of the conjugated diene rubber reacted with an activity control agent to react with a modifier having an alkoxy group and a halogen atom-containing group so as to obtain a modified conjugated diene rubber.

Method of production of modified conjugated diene rubber

A method of production of a modified conjugated diene rubber including a first step of polymerizing a monomer containing at least a conjugated diene compound by using a polymerization initiator in an inert solvent so as to obtain a conjugated diene polymer having an active end, and a second step of causing a compound represented by a following formula (1) to react with the active end of the conjugated diene polymer having an active end:  wherein, in formula (1), each of Rto Rindependently is an alkyl group having 1 to 4 carbon atoms, Ris a hydrocarbon group containing an aromatic ring and having 6 to 10 carbon atoms, Ris an alkyl group having 1 to 6 carbon atoms, and 'n' is an integer of 0 to 10.

Provided is a rubber composition for a tire containing a rubber component including 15 to 55 wt % of an end modified group-containing cycloolefin ring-opening polymer having a glass transition temperature of &#x2212;120 to &#x2212;90&#xb0; C. and 45 to 85 wt % of an end modified group-containing solution polymerized conjugated diene polymer having a glass transition temperature of &#x2212;60 to &#x2212;10&#xb0; C. and having an aromatic vinyl monomer unit content ratio of more than 30 wt % and 50 wt % or less, a silica, and a silane coupling agent including a monosulfide group and/or a thiol group, wherein the content of the silica with respect to 100 parts by weight of the rubber component is 30 to 200 parts by weight, and the content of the silane coupling agent including a monosulfide group and/or a thiol group with respect to 100 parts by weight of the silica is 0.3 to 20 parts by weight.

Rubber composition for tire

A method of production of modified conjugated diene-based rubber comprising a steps of using, as a polymerization initiator, an alkali metalated aromatic compound which has three or more carbon atoms which are directly bonded to alkali metal atoms and aromatic rings in one molecule so as to polymerize a monomer which contains at least a conjugated diene compound and reacting a compound of the following general formula (I) with an active ends of the obtained polymer is provided.  (In the general formula (I), any one of Rand Rto Ris an atom or reactive group which can react with the active ends of said polymer or a hydrocarbon group which includes either of the same, the remaining among Rand Rto Rand Rto Rare respectively independently a hydrogen atom, alkyl group, or aryl group, and 'j', 'k', &#x201c;m&#x201d;, and &#x201c;n&#x201d; are integers of 0 to 100.)

Method of production of modified conjugated diene-based rubber

An alkali metal-reacted aromatic compound which has three or more carbon atoms which are directly bonded to alkali metal atoms and aromatic rings in one molecule is used as a polymerization initiator to polymerize a monomer mixture which is contains at least one conjugated diene compound to thereby produce a radial conjugated diene polymer. Further, active ends of the polymer having active ends which is obtained by this method is made to react with a modifier which can react with the active ends to thereby produce an end-modified radial conjugated diene polymer. According to the present invention, it is possible to provide a method of production of the radial conjugated diene polymer which gives a high degree of freedom of polymer design and easy control of the polymer structure.

Method of production of radial conjugated diene polymer

For a tire excellent in strength, low-heat buildup property, wet grip property, and driveability, and a rubber composition and a conjugated diene rubber for the tire, a conjugated diene rubber of the present invention includes 5 wt % or more of a structure that 3 or more conjugated diene polymer chains are bound via a denaturing agent, obtained by reaction of each chain and the agent, each chain being that at least one of terminals is an isoprene block having 70 wt % or more of an isoprene monomer unit, and the other is an active terminal, the agent having, per molecule, at least one of an epoxy group(s) and a hydrocarbyloxysilyl group(s), and being that a total number of the epoxy group(s) and hydrocarbyloxy groups in the hydrocarbyloxysilyl group(s) per molecule is 3 or more.

Conjugated diene rubber, rubber composition, crosslinked rubber, tire, and process for production of conjugated diene rubber

A conjugated diene rubber of the present invention is prepared from conjugated diene polymer chains, wherein the conjugated diene polymer chains each has an active end at one end and an isoprene block at least at the other end, the isoprene block contains 70 wt % or more isoprene monomer units, and the active ends of at least part of the conjugated diene polymer chains are modified with a compound having a &#x3e;C&#x2550;O group as a functional group. This provides (i) a tire that has an excellent strength, excellent low-heat buildup property, and excellent wet grip property and (ii) a rubber composition and a conjugated diene rubber that are suitably used to produce the tire.

Conjugated diene rubber, rubber composition, cross-linked rubber, and tire

A cyclopentene ring-opening polymer which has hydroxy groups at the polymer chain terminal ends is produced, then the hydroxy groups of the cyclopentene ring-opening polymer and isocyanate groups of a compound containing alkoxysilyl groups and isocyanate groups in its molecule are made to react to thereby produce a cyclopentene ring-opening polymer which contains structures at the polymer chain terminal ends where the polymer chains and groups including alkoxysilyl groups are bonded through urethane bond groups and which has a weight average molecular weight of 100,000 to 1,000,000.

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Tokyo, Japan

Takeshi Sugimura