Ring-opening copolymer, rubber composition, rubber crosslinked product, and tire

Abstract

Provided is a ring-opening copolymer with which it is possible to form a crosslinked rubber having an excellent balance among mechanical strength, wet grip, and low heat generation. Provided is a ring-opening copolymer containing a structural unit derived from cyclooctene and a structural unit derived from a norbornene compound having a tricyclic or higher ring.

Description

Technical Field

[0001] The present invention relates to a ring-opening copolymer, a rubber composition, a rubber crosslinked product, and a tire. Background Art

[0002] It is known that cyclopentene and norbornene compounds are usually subjected to ring-opening metathesis polymerization in the presence of a so-called Ziegler-Natta catalyst composed of a Group 6 transition metal compound such as WCl6 and MoCl5 in the periodic table, and an organometallic activator such as triisobutylaluminum, diethylaluminum chloride, and tetrabutyltin, thereby forming an unsaturated linear ring-opening copolymer.

[0003] For example, Patent Document 1 discloses a ring-opening copolymer containing a structural unit derived from a norbornene compound represented by a specific general formula (1) and a structural unit derived from a monocyclic cyclic olefin. With respect to all the repeating structural units in the above ring-opening copolymer, the content ratio of the structural unit derived from the norbornene compound is 25 to 90% by weight, and the content ratio of the structural unit derived from the monocyclic cyclic olefin is 10 to 75% by weight. The weight-average molecular weight of the above ring-opening copolymer is 100,000 to 1,000,000, and the cis / trans ratio in the above ring-opening copolymer is 0 / 100 to 50 / 50. According to the technology of Patent Document 1, a rubber crosslinked product excellent in mechanical strength, elongation characteristics, and resilience can be formed.

[0004] Prior Art Documents

[0005] Patent Documents

[0006] Patent Document 1: International Publication No. 2019 / 208239. Summary of the Invention

[0007] Problems to be Solved by the Invention

[0008] When the ring-opening copolymer is used as a material for tire applications, it is required to be able to achieve the performance required for tires, such as low heat generation, in a balanced manner. On the other hand, in Patent Document 1, the performance such as low heat generation has not been studied.

[0009] The present invention has been completed in view of such actual circumstances, and an object thereof is to provide a ring-opening copolymer capable of forming a rubber crosslinked product excellent in mechanical strength, wet grip, and low heat generation in a balanced manner.

[0010] Solutions to the Problems

[0011] The inventors of the present invention conducted in-depth research to achieve the above object, and as a result, found that the above object can be achieved according to a ring-opening copolymer containing a structural unit derived from cyclooctene and a structural unit derived from a norbornene compound having three or more rings, thereby completing the present invention.

[0012] That is, according to the present invention, the following ring-opening copolymer, rubber composition, rubber crosslinked product, and tire can be provided.

[0013] [1] A ring-opening copolymer containing structural units derived from cyclooctene and structural units derived from a norbornene compound having three or more rings.

[0014] [2] The ring-opening copolymer according to [1], wherein the content ratio of the structural units derived from cyclooctene is 10 to 95% by weight, and the content ratio of the structural units derived from the norbornene compound having three or more rings is 5 to 90% by weight, based on all the repeating structural units in the ring-opening copolymer.

[0015] [3] The ring-opening copolymer according to [1] or [2], wherein the norbornene compound having three or more rings is a norbornene compound having 3 to 6 ring structures.

[0016] [4] The ring-opening copolymer according to any one of [1] to [3], wherein the norbornene compound having three or more rings is a compound represented by the following general formula (1) and / or a compound represented by the following general formula (2).

[0017] [Chemical formula 1]

[0018]

[0019] (In the above general formula (1), R 1 and R 2 each independently represent: a hydrogen atom; a halogen atom; a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent; or a substituent containing a silicon atom, an oxygen atom or a nitrogen atom, and R 1 and R 2 can bond to each other to form a ring. R 3 represents a divalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent.)

[0020] [Chemical formula 2]

[0021]

[0022] (In the above general formula (2), R 4 to R 7 each independently represent: a hydrogen atom; a halogen atom; a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent; or a substituent containing a silicon atom, an oxygen atom or a nitrogen atom, and R 4 and R 6 , or R 4 and R 5 can bond to each other to form a ring; and / or R 6 and R7 which can bond to each other to form a ring. n is 1 or 2.)

[0023] [5] The ring-opening copolymer according to any one of [1] to [4], wherein the weight-average molecular weight (Mw) of the ring-opening copolymer is 10,000 to 1,000,000, the cis / trans ratio is 90 / 10 to 5 / 95, and the glass transition temperature (Tg) is -100 to 20 °C.

[0024] [6] A rubber composition comprising the ring-opening copolymer according to any one of [1] to [5].

[0025] [7] The rubber composition according to [6], wherein the rubber composition further comprises a filler.

[0026] [8] The rubber composition according to [6] or [7], wherein the rubber composition further comprises a crosslinking agent.

[0027] [9] A rubber crosslinking product obtained by crosslinking the rubber composition according to any one of [6] to [8].

[0028]

[10] A tire comprising the rubber crosslinking product according to [9].

[0029] Advantages of the Invention

[0030] According to the present invention, a ring-opening copolymer can be provided, which can form a rubber crosslinking product having excellent balance in mechanical strength, wet grip performance, and low heat generation. Detailed Embodiments

[0031] <Ring-Opening Copolymer>

[0032] The ring-opening copolymer of the present invention is obtained by ring-opening copolymerization of cyclooctene and a norbornene compound having three or more rings, and is a ring-opening copolymer comprising a structural unit derived from cyclooctene and a structural unit derived from a norbornene compound having three or more rings.

[0033] As the norbornene compound having three or more rings used in the present invention, any compound may be used as long as it contains a norbornene ring and has a ring structure of three or more rings, and there is no particular limitation. Preferably, it has 3 to 6 ring structures, and more preferably 3 to 4 ring structures. In the present invention, the norbornene compound having three or more rings may be used alone or in combination of two or more.

[0034] As a norbornene compound having three or more rings, it refers to a compound containing a norbornene ring and a ring condensed with the norbornene ring, and examples thereof include a norbornene compound having a heterocyclic ring condensed with the norbornene ring and a norbornene compound having a fused ring of a norbornene ring and a hydrocarbon ring. Among these, from the aspect of being able to make the effects of the present invention more significant, a norbornene compound having a fused ring of a norbornene ring and a hydrocarbon ring is preferred.

[0035] As a norbornene compound having a heterocyclic ring condensed with the norbornene ring, examples thereof include, for example, norbornene-5,6-dicarboxylic anhydride, norbornene-5,6-dicarboximide, and the like.

[0036] As a norbornene compound having a fused ring of a norbornene ring and a hydrocarbon ring, examples thereof include a compound represented by the following general formula (1) (excluding the compound represented by the following general formula (2)) or a compound represented by the following general formula (2).

[0037] [Chemical formula 3]

[0038]

[0039] (In the above general formula (1), R 1 and R 2 each independently represent: a hydrogen atom; a halogen atom; a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent; or a substituent containing a silicon atom, an oxygen atom or a nitrogen atom, and R 1 and R 2 can bond to each other to form a ring. R 3 represents a divalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent.)

[0040] [Chemical formula 4]

[0041]

[0042] (In the above general formula (2), R 4 to R 7 each independently represent: a hydrogen atom; a halogen atom; a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent; or a substituent containing a silicon atom, an oxygen atom or a nitrogen atom, and R 4 and R 6 , or R 4 and R 5 can bond to each other to form a ring; and / or R 6 and R 7 can bond to each other to form a ring. n is 1 or 2.)

[0043] In the above general formula (1), R 1 and R 2Each independently represents: a hydrogen atom; a halogen atom; a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent; or a substituent containing a silicon atom, an oxygen atom or a nitrogen atom. R 1 and R 2 may be the same or different.

[0044] As a hydrocarbon group having 1 to 20 carbon atoms as one mode of R 1 and R 2 Examples include: alkyl groups having 1 to 20 carbon atoms such as methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl; alkenyl groups having 2 to 20 carbon atoms such as vinyl, allyl; alkynyl groups having 2 to 20 carbon atoms such as ethynyl, propargyl. The hydrocarbon group having 1 to 20 carbon atoms may be linear or branched, for example.

[0045] As a hydrocarbon group having 1 to 20 carbon atoms as one mode of R 1 and R 2 The hydrocarbon group having 1 to 20 carbon atoms may have a substituent or may not have a substituent. Examples of the substituent include: carbonyl-containing groups such as carboxyl, acid anhydride, hydrocarbon group carbonyl, alkoxycarbonyl, acyloxy; epoxy group; oxy group; cyano group; amino group; halogen group and other substituents other than hydrocarbon groups.

[0046] As a substituent containing a silicon atom, an oxygen atom or a nitrogen atom as one mode of R 1 and R 2 Examples include: alkoxysilyl; carbonyl-containing groups such as carboxyl, acid anhydride, hydrocarbon group carbonyl, alkoxycarbonyl, acyloxy; epoxy group; oxy group; cyano group; amino group.

[0047] In the above general formula (1), R 1 and R 2 can bond to each other to form a ring, and R 1 and R 2 may also not bond to each other.

[0048] As R 1 and R 2 each independently is preferably a hydrogen atom and a hydrocarbon having 1 to 20 carbon atoms, more preferably a hydrogen atom and a hydrocarbon having 1 to 10 carbon atoms, and still more preferably a hydrogen atom.

[0049] In the above general formula (1), R 3Represents a divalent hydrocarbon group having 1 to 20 carbon atoms that can have substituents. Examples of the divalent hydrocarbon group having 1 to 20 carbon atoms include an alkylene group having 1 to 20 carbon atoms, an alkenylene group having 2 to 20 carbon atoms, a cycloalkylene group having 3 to 20 carbon atoms, a cycloalkylalkylene group having 4 to 20 carbon atoms, an arylene group having 6 to 20 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, and the like. The alkylene group and the alkenylene group can be either linear or branched, and the cycloalkylene group, the cycloalkylalkylene group, the arylene group, and the aralkyl group can have substituents such as lower alkyl groups on the ring.

[0050] As R 3 's divalent hydrocarbon group having 1 to 20 carbon atoms can have substituents or can be unsubstituted. Examples of the substituents include carbonyl-containing groups such as carboxyl group, acid anhydride group, hydrocarbonyl group, alkoxycarbonyl group, acyloxy group; epoxy group; oxy group; cyano group; amino group; halogen group and other substituents other than hydrocarbon groups.

[0051] R 3 The number of carbon atoms of R

[0052] As long as it is 1 to 20, there is no particular limitation, preferably 2 to 15, more preferably 3 to 10. 3 Preferably, R

[0053] is an alkenylene group having 2 to 20 carbon atoms and an aralkyl group having 7 to 20 carbon atoms, and more preferably an alkenylene group having 2 to 10 carbon atoms. 2,6 dec-8-ene, tetracyclo[9.2.1.0 2,10 .0 3,8 tetradeca-3,5,7,12-tetraene (also known as 1,4-methano-1,4,4a,9a-tetrahydro-9H-fluorene), tetracyclo[10.2.1.0 2,11 .0 4,9 pentadeca-4,6,8,13-tetraene (also known as 1,4-methano-1,4,4a,9,9a,10-hexahydroanthracene) and other bicyclo[2.2.1]hept-2-ene compounds condensed from hydrocarbon rings.

[0054] In the above general formula (2), R 4 to R 7 each independently represent: a hydrogen atom; a halogen atom; a hydrocarbon group having 1 to 20 carbon atoms that can have substituents; or a substituent containing a silicon atom, an oxygen atom or a nitrogen atom. R 4 to R 7 can be the same or different.

[0055] As R 4 to R7 One type of hydrocarbyl group having 1 to 20 carbon atoms that can have substituents, examples of which include the same hydrocarbyl groups as those of R 1 and R 2 One type of hydrocarbyl group having 1 to 20 carbon atoms that can have substituents.

[0056] In the above general formula (2), R 4 and R 6 can bond to each other to form a ring, and R 4 and R 6 can also not bond to each other. In addition, at least one of R 4 and R 5 and at least one of R 6 and R 7 can bond to each other to form a ring, and R 4 and R 5 and R 6 and R 7 can also both not bond to each other.

[0057] As R 4 to R 7 , each is independently preferably a hydrogen atom and a hydrocarbyl having 1 to 20 carbon atoms, more preferably a hydrogen atom and a hydrocarbyl having 1 to 10 carbon atoms, and still more preferably a hydrogen atom.

[0058] In the above general formula (2), n is 1 or 2, preferably 1.

[0059] Specific examples of the compound represented by the above general formula (2) include: tetracyclo[6.2.1.1 3,6 .0 2,7 dodec-4-ene, 9-methyltetracyclo[6.2.1.1 3,6 .0 2,7 dodec-4-ene, 9-ethyltetracyclo[6.2.1.1 3,6 .0 2,7 dodec-4-ene, 9-cyclohexyltetracyclo[6.2.1.1 3,6 .0 2,7 dodec-4-ene, 9-cyclopentyltetracyclo[6.2.1.1 3,6 .0 2,7 dodec-4-ene, 9-methylene-tetracyclo[6.2.1.1 3,6 .0 2,7 dodec-4-ene, 9-ethylidene-tetracyclo[6.2.1.1 3,6 .0 2,7 dodec-4-ene, 9-vinyltetracyclo[6.2.1.1 3,6 .0 2,7 dodec-4-ene, 9-propenyltetracyclo[6.2.1.13,6 .0 2 ,7 Dodec-4-ene, 9-cyclohexenyltetracyclo[6.2.1.1 3,6 .0 2,7 Dodec-4-ene, 9-cyclopentenyltetracyclo[6.2.1.1 3,6 .0 2,7 Dodec-4-ene and 9-phenyltetracyclo[6.2.1.1 3,6 .0 2,7 Dodec-4-ene and other unsubstituted or hydrocarbon-substituted tetracyclo[6.2.1.1 3,6 .0 2,7 Dodec-4-ene;

[0060] Tetracyclo[6.2.1.1 3,6 .0 2,7 Methyl dodec-9-ene-4-carboxylate and 4-methyltetracyclo[6.2.1.1 3,6 .0 2,7 Methyl dodec-9-ene-4-carboxylate and other tetracyclo[6.2.1.1 with an alkoxycarbonyl group 3,6 .0 2,7 Dodec-4-ene;

[0061] Tetracyclo[6.2.1.1 3,6 .0 2,7 Dodec-9-ene-4-carboxylic acid, tetracyclo[6.2.1.1 3,6 .0 2,7 Dodec-9-ene-4,5-dicarboxylic acid and tetracyclo[6.2.1.1 3,6 .0 2,7 Dodec-9-ene-4,5-dicarboxylic anhydride and other tetracyclo[6.2.1.1 with a hydroxycarbonyl or anhydride group 3,6 .0 2,7 Dodec-4-ene;

[0062] Tetracyclo[6.2.1.1 3,6 .0 2,7 Dodec-9-ene-4-methanol and tetracyclo[6.2.1.1 3,6 .0 2,7 Dodec-4-ene-9-ol and other tetracyclo[6.2.1.1 with a hydroxy group 3,6 .0 2,7 Dodec-4-ene;

[0063] Tetracyclo[6.2.1.1 3,6 .0 2,7 Dodec-9-ene-4-carbaldehyde and other tetracyclo[6.2.1.1 with a hydrocarbylcarbonyl group 3,6 .02 ,7 Dodec-4-enes;

[0064] 9-Tricyclo[6.2.1.1 3,6 .0 2,7 dodec-4-enyl acetate, 9-tricyclo[6.2.1.1 3,6 .0 2,7 dodec-4-enyl acrylate, and 9-tricyclo[6.2.1.1 3,6 .0 2,7 dodec-4-enyl methacrylate, etc., tricyclo[6.2.1.1 3,6 .0 2,7 dodec-4-enes;

[0065] Tricyclo[6.2.1.1 3,6 .0 2,7 dodec-9-en-4-carbonitrile, tricyclo[6.2.1.1 3,6 .0 2,7 dodec-9-en-4-carboxamide, and tricyclo[6.2.1.1 3,6 .0 2,7 dodec-9-en-4,5-dicarboximide, etc., tricyclo[6.2.1.1 3,6 .0 2,7 dodec-4-enes;

[0066] 9-Chlorotricyclo[6.2.1.1 3,6 .0 2,7 dodec-4-ene, etc., tricyclo[6.2.1.1 3,6 .0 2,7 dodec-4-enes;

[0067] 4-Trimethoxysilyltricyclo[6.2.1.1 3,6 .0 2,7 dodec-4-ene, 4-triethoxysilyltricyclo[6.2.1.1 3,6 .0 2,7 dodec-4-ene, etc., tricyclo[6.2.1.1 3,6 .0 2,7 dodec-4-enes.

[0068] The norbornene compounds having three or more rings can be used alone or in combination of two or more. As the norbornene compounds having three or more rings, from the aspect of being able to further significantly enhance the effects of the present invention, the compounds represented by the above general formula (1) and tricyclo[6.2.1.13,6 .0 2,7 Dodec-4-enes, more preferably dicyclopentadiene, 1,4-methano-1,4,4a,9a-tetrahydro-9H-fluorene, and tetracyclo[6.2.1.1 3,6 .0 2 ,7 dodec-4-ene. Further, from the viewpoint of being able to form a rubber crosslink having excellent abrasion resistance and further excellent mechanical strength and low heat generation, dicyclopentadiene and tetracyclo[6.2.1.1 3 ,6 .0 2,7 dodec-4-enes which are unsubstituted or have a hydrocarbon substituent are preferred; from the viewpoint of being able to form a rubber crosslink having further excellent wet grip performance, the compound represented by the above general formula (1) is preferred.

[0069] In the ring-opening copolymer of the present invention, the content ratio of the structural unit derived from cyclooctene relative to all repeating structural units is preferably 10 to 95% by weight. Further, the content ratio of the structural unit derived from cyclooctene relative to all repeating structural units, from the viewpoint of being able to form a rubber crosslink having excellent abrasion resistance and further excellent low heat generation, is preferably 15% by weight or more, more preferably 40% by weight or more, and still more preferably 55% by weight or more; from the viewpoint of being able to form a rubber crosslink having abrasion resistance and mechanical strength with further excellent balance, it is preferably 10 to 95% by weight, more preferably 25 to 90% by weight; from the viewpoint of being able to form a rubber crosslink having wet grip performance, low heat generation, and abrasion resistance with further excellent balance, it is preferably 40 to 85% by weight, more preferably 55 to 85% by weight.

[0070] In the ring-opening copolymer of the present invention, the content ratio of the structural unit derived from a norbornene compound having three or more rings relative to all repeating structural units is preferably 5 to 90% by weight. Further, the content ratio of the structural unit derived from a norbornene compound having three or more rings relative to all repeating structural units, from the viewpoint of being able to form a rubber crosslink having excellent abrasion resistance and further excellent low heat generation, is preferably 85% by weight or less, more preferably 60% by weight or less, and still more preferably 45% by weight or less; from the viewpoint of being able to form a rubber crosslink having abrasion resistance and mechanical strength with further excellent balance, it is preferably 5 to 90% by weight, more preferably 10 to 75% by weight; from the viewpoint of being able to form a rubber crosslink having wet grip performance, low heat generation, and abrasion resistance with further excellent balance, it is preferably 15 to 60% by weight, more preferably 15 to 45% by weight.

[0071] In addition, in addition to cyclooctene and norbornene compounds having three or more rings, the ring-opening copolymer of the present invention may also be a ring-opening copolymer formed by copolymerizing other monomers capable of copolymerizing with them. As such other monomers, monocyclic olefins, monocyclic dienes, monocyclic trienes, etc. other than cyclooctene can be cited. As monocyclic olefins other than cyclooctene, cyclopropene, cyclobutene, cyclopentene, methylcyclopentene, cyclohexene, methylcyclohexene, cycloheptene, etc. can be exemplified. As monocyclic dienes, 1,5-cyclooctadiene can be exemplified. As monocyclic trienes, 1,5,9-cyclododecatriene can be exemplified. In the ring-opening copolymer of the present invention, the content ratio of the structural unit derived from other monomers with respect to all repeating structural units is preferably 30% by weight or less, more preferably 15% by weight or less, and particularly preferably substantially 0% by weight.

[0072] In addition, in the ring-opening copolymer of the present invention, the content ratio of the structural unit derived from cyclopentene with respect to all repeating structural units is preferably 5% by weight or less, more preferably 1% by weight or less, and particularly preferably substantially 0%.

[0073] The weight-average molecular weight (Mw) of the ring-opening copolymer of the present invention, as the value of the weight-average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography, is preferably 10,000 to 1,000,000, more preferably 50,000 to 8,000,000, and further preferably 80,000 to 600,000. By making the weight-average molecular weight (Mw) within the above range, rubber properties can be made sufficient and manufacturing and operation can be good. In addition, the ratio (Mw / Mn) of the weight-average molecular weight (Mw) to the number-average molecular weight (Mn) of the ring-opening copolymer of the present invention measured by gel permeation chromatography in terms of polystyrene is preferably 1.0 to 5.0, more preferably 1.5 to 2.5.

[0074] From the aspect of being able to make the effects of the present invention more remarkable, the cis / trans ratio of the ring-opening copolymer of the present invention is preferably 90 / 10 to 5 / 95, more preferably 70 / 30 to 10 / 90, and further preferably 50 / 50 to 15 / 85. The above cis / trans ratio is the content ratio (cis / trans ratio) of the cis structure and the trans structure of the double bond present in the repeating unit constituting the ring-opening copolymer of the present invention.

[0075] From the aspect of being able to make the effects of the present invention more remarkable, the glass transition temperature (Tg) of the ring-opening copolymer of the present invention is preferably -100 to 20 °C, more preferably -90 to -0 °C, and further preferably -80 to -20 °C. In addition, the glass transition temperature of the ring-opening copolymer can be controlled by, for example, adjusting the type and amount of the norbornene compound having three or more rings used.

[0076] In addition, the ring-opening copolymer of the present invention may have a modifying group at the polymer chain end. The modifying group introduced at the polymer chain end is not particularly limited, and a modifying group containing an atom selected from the atoms of Group 15 of the periodic table, the atoms of Group 16 of the periodic table, and silicon atoms is preferred.

[0077] From the viewpoint of being able to improve the affinity with fillers such as silica and thereby making the breaking strength and abrasion resistance better when forming a rubber crosslinked product, as the modifying group for forming the terminal modifying group, a modifying group containing an atom selected from nitrogen atoms, oxygen atoms, phosphorus atoms, sulfur atoms, and silicon atoms is more preferred, and among these, a modifying group containing an atom selected from nitrogen atoms, oxygen atoms, and silicon atoms is further preferred.

[0078] Examples of the modifying group containing a nitrogen atom include amino, pyridyl, imino, amide, nitro, urethane bond group, or a hydrocarbon group containing any of these groups. Examples of the modifying group containing an oxygen atom include hydroxyl, carboxyl, ether, ester, carbonyl, aldehyde, epoxy, or a hydrocarbon group containing any of these groups. Examples of the modifying group containing a silicon atom include alkylsilyl, oxysilyl, or a hydrocarbon group containing any of these groups. Examples of the modifying group containing a phosphorus atom include phosphoric acid group, phosphino, or a hydrocarbon group containing any of these groups. Examples of the modifying group containing a sulfur atom include sulfonyl, mercapto, thioether, or a hydrocarbon group containing any of these groups. In addition, as the modifying group, it may also be a modifying group containing a plurality of the above groups. In addition, oxysilyl refers to a group having a silicon-oxygen bond.

[0079] Specific examples of oxysilyl include alkoxysilyl, aryloxysilyl, acyloxy, alkylsiloxysilyl, or arylsiloxysilyl, etc. In addition, hydroxysilyl obtained by hydrolyzing alkoxysilyl, aryloxysilyl, or acyloxy can be cited.

[0080] Alkoxysilyl is a group in which one or more alkoxy groups are bonded to a silicon atom. Specific examples thereof include: trimethoxysilyl, (dimethoxy)(methyl)silyl, (methoxy)(dimethyl)silyl, (methoxy)(dichloro)silyl, triethoxysilyl, (diethoxy)(methyl)silyl, (ethoxy)(dimethyl)silyl, (dimethoxy)(ethoxy)silyl, (methoxy)(diethoxy)silyl, tripropoxysilyl, tris(trimethylsiloxy)silyl, etc.

[0081] The introduction ratio of the modifying group at the polymer chain end of the ring-opening copolymer of the present invention is not particularly limited, and as the percentage value of the number of ring-opening copolymer chain ends having the modifying group / the total number of ring-opening copolymer chain ends, it can be 10% or more.

[0082] The Mooney viscosity (ML1+4, 100 °C) of the ring-opening copolymer of the present invention is preferably 20 to 150, more preferably 30 to 130, and further preferably 40 to 110. By making the Mooney viscosity within the above range, the kneading at normal temperature and high temperature can be facilitated, and thus the processability can be improved.

[0083] <Method for producing ring-opening copolymer>

[0084] The method for producing the ring-opening copolymer of the present invention is not particularly limited, and examples thereof include a method of copolymerizing cyclooctene and a norbornene compound having three or more rings in the presence of a ring-opening polymerization catalyst.

[0085] The ring-opening polymerization catalyst only needs to be able to copolymerize cyclooctene and a norbornene compound having three or more rings by ring-opening. Particularly preferred are ruthenium carbene complexes and so-called Ziegler-Natta catalysts. The ring-opening polymerization catalyst can be used alone or in combination of two or more.

[0086] Specific examples of the ruthenium carbene complex include: bis(tricyclohexylphosphine)benzylidene dichlororuthenium, bis(triphenylphosphine)-3,3-diphenylallylidene dichlororuthenium, bis(tricyclohexylphosphine)tert-butylvinylidene dichlororuthenium, dichloro-(3-phenyl-1H-inden-1-ylidene)bis(tricyclohexylphosphine)ruthenium, bis(1,3-diisopropylimidazolin-2-ylidene)benzylidene dichlororuthenium, bis(1,3-dicyclohexylimidazolin-2-ylidene)benzylidene dichlororuthenium, (1,3-dimesitylimidazolin-2-ylidene)(tricyclohexylphosphine)benzylidene dichlororuthenium, (1,3-dimesitylimidazolidin-2-ylidene)(tricyclohexylphosphine)benzylidene dichlororuthenium (the above-mentioned compound is also called dichloro[1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene](benzylidene)(tricyclohexylphosphine)ruthenium(II)), bis(tricyclohexylphosphine)ethoxymethylene dichlororuthenium, (1,3-dimesitylimidazolidin-2-ylidene)(tricyclohexylphosphine)ethoxymethylene dichlororuthenium.

[0087] Ziegler-Natta catalysts are mixed catalysts of Group 6 transition metal compounds of the periodic table and organoaluminum compounds. Specific examples of Group 6 transition metal compounds of the periodic table include: molybdenum compounds such as molybdenum pentachloride, molybdenum oxytetrachloride, (phenylimide) molybdenum tetrachloride, ammonium tri-dodecyl molybdate, ammonium methyltrioctyl molybdate, ammonium tridecyl molybdate, ammonium trioctyl molybdate, ammonium tetraphenyl molybdate, etc.; tungsten compounds such as tungsten hexachloride, tungsten oxytetrachloride, (phenylimide) tungsten tetrachloride, mono-catechol tungsten tetrachloride, bis(3,5-di-tert-butyl) catechol tungsten dichloride, bis(2-chloroethyl ether complex) tungsten tetrachloride, tungsten tetraphenol oxide, etc.

[0088] Specific examples of the organoaluminum compounds contained in the Ziegler-Natta catalyst include: diethylaluminum ethoxide, diethylaluminum isopropoxide, diisobutylaluminum butoxide, diisobutylaluminum hexyloxide, diethylaluminum (2-trichloroethoxy), diethylaluminum (2-tribromoethoxy), diethylaluminum (1,3-dichloro-2-propoxy), diethylaluminum (1,1,1,3,3,3-hexafluoro-2-propoxy), diethylaluminum (1,1,1-trichloro-2-methyl-2-propoxy), diethylaluminum (2,6-diisopropylphenoxy), diethylaluminum bis(2-trichloroethoxy), diethylaluminum bis(2-tribromoethoxy), diethylaluminum bis(1,3-dichloro-2-propoxy), diethylaluminum bis(1,1,1,3,3,3-hexafluoro-2-propoxy), diethylaluminum bis(1,1,1-trichloro-2-methyl-2-propoxy), bis(2,6-diisopropylphenoxy)ethylaluminum, ethyl(chloro)aluminum ethoxide, ethyl(chloro)aluminum isopropoxide, ethyl(chloro)aluminum butoxide, ethyl(chloro)aluminum (2-trichloroethoxy), ethyl(chloro)aluminum (2-tribromoethoxy), ethyl(bromo)aluminum (1,3-dichloro-2-propoxy), ethyl(chloro)aluminum (1,1,1,3,3,3-hexafluoro-2-propoxy), ethyl(chloro)aluminum (1,1,1-trichloro-2-methyl-2-propoxy), ethyl(chloro)aluminum (2,6-diisopropylphenoxy), etc.

[0089] The usage amount of the ring-opening polymerization catalyst is generally in the range of 1:500 to 1:2,000,000, preferably 1:700 to 1:1,500,000, and more preferably 1:1,000 to 1:1,000,000 in terms of the molar ratio of (ring-opening polymerization catalyst: monomers used in copolymerization).

[0090] The polymerization reaction can be carried out without solvent or in solution. In the case of carrying out copolymerization in solution, the solvent used is not particularly limited as long as it is inactive in the polymerization reaction and can dissolve the cyclooctadiene, norbornene compound, polymerization catalyst, etc. used in the copolymerization. Hydrocarbon solvents or halogenated solvents are preferably used. As hydrocarbon solvents, for example, aromatic hydrocarbons such as benzene, toluene, xylene, and ethylbenzene; aliphatic hydrocarbons such as hexane, n-heptane, and n-octane; alicyclic hydrocarbons such as cyclohexane, cyclopentane, and methylcyclohexane, etc. can be cited. In addition, as halogenated solvents, for example, halogenated alkanes such as dichloromethane and chloroform; aromatic halogenated compounds such as chlorobenzene and dichlorobenzene, etc. can be cited. These solvents can be used alone or in combination of two or more.

[0091] When carrying out ring-opening copolymerization of cyclooctene and a norbornene compound having three or more rings, an olefin compound or a diene compound can be added to the polymerization reaction system as a molecular weight regulator as needed to adjust the molecular weight of the obtained ring-opening copolymer.

[0092] As the olefin compound, there is no particular limitation as long as it is an organic compound having an olefinic unsaturated bond. For example, α-olefins such as 1-butene, 1-pentene, 1-hexene, and 1-octene; styrenes such as styrene and vinyltoluene; halogenated vinyl compounds such as allyl chloride; vinyl ethers such as ethyl vinyl ether and isobutyl vinyl ether; amine-containing vinyl compounds such as allylamine, N,N-dimethylallylamine, and N,N-diethylallylamine; disubstituted olefins such as 2-butene and 3-hexene, etc. can be cited.

[0093] As the diene compound, non-conjugated dienes such as 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,6-heptadiene, 2-methyl-1,4-pentadiene, and 2,5-dimethyl-1,5-hexadiene can be cited.

[0094] The usage amounts of the olefin compound and the diene compound as the molecular weight regulator can be appropriately selected according to the molecular weight of the produced ring-opening copolymer. Usually, the molar ratio is 1 / 100 to 1 / 100000 relative to the monomers used in the copolymerization, preferably 1 / 200 to 1 / 50000, and more preferably in the range of 1 / 500 to 1 / 10000.

[0095] In addition, when the ring-opening copolymer in the present invention has a modified group at the polymer chain end, as the molecular weight regulator, an olefinic unsaturated hydrocarbon compound containing a modified group is preferably used instead of the above-mentioned olefin compound and diene compound. By using such an olefinic unsaturated hydrocarbon compound containing a modified group, a modified group can be preferably introduced at the polymer chain end of the ring-opening copolymer obtained by copolymerization.

[0096] As an ethylenically unsaturated hydrocarbon compound containing a modifying group, any compound having a modifying group and an ethylenic carbon-carbon double bond with metathesis reactivity can be used, and there is no particular limitation. For example, when it is desired to introduce an oxymethylsilyl group at the end of the polymer chain of the ring-opening copolymer, it is sufficient to make an ethylenically unsaturated hydrocarbon containing an oxymethylsilyl group present in the polymerization reaction system.

[0097] Examples of such ethylenically unsaturated hydrocarbons containing an oxymethylsilyl group, as examples of introducing a modifying group only at one end (a single end) of the polymer chain of the ring-opening copolymer, include: alkoxysilane compounds such as vinyl(trimethoxy)silane, vinyl(triethoxy)silane, allyl(trimethoxy)silane, allyl(methoxy)(dimethyl)silane, allyl(triethoxy)silane, allyl(ethoxy)(dimethyl)silane, styryl(trimethoxy)silane, styryl(triethoxy)silane, styrylethyl(triethoxy)silane, allyl(triethoxysilylmethyl)ether, allyl(triethoxysilylmethyl)(ethyl)amine; aryloxysilane compounds such as vinyl(triphenoxy)silane, allyl(triphenoxy)silane, allyl(phenoxy)(dimethyl)silane; acyloxysilane compounds such as vinyl(triacetoxy)silane, allyl(triacetoxy)silane, allyl(diacetoxy)methylsilane, allyl(acetoxy)(dimethyl)silane; alkylsiloxysilane compounds such as allyltris(trimethylsiloxy)silane; arylsiloxysilane compounds such as allyltris(triphenylsiloxy)silane; polysiloxane compounds such as 1-allylheptamethyltrisiloxane, 1-allylnonamethyltetrasiloxane, 1-allylnonamethylcyclopentasiloxane, 1-allylundecamethylcyclohexasiloxane, etc.

[0098] In addition, as examples of introducing modifying groups at both ends (two ends) of the polymer chain of the ring-opening copolymer, include: alkoxysilane compounds such as bis(trimethoxysilyl)ethylene, bis(triethoxysilyl)ethylene, 2-butene-1,4-bis(trimethoxysilane), 2-butene-1,4-bis(triethoxysilane), 1,4-bis(trimethoxysilylmethoxy)-2-butene; aryloxysilane compounds such as 2-butene-1,4-bis(triphenoxysilane); acyloxysilane compounds such as 2-butene-1,4-bis(triacetoxysilane); alkylsiloxysilane compounds such as 2-butene-1,4-bis[tris(trimethylsiloxy)silane]; arylsiloxysilane compounds such as 2-butene-1,4-bis[tris(triphenylsiloxy)silane]; polysiloxane compounds such as 2-butene-1,4-bis(heptamethyltrisiloxane), 2-butene-1,4-bis(undecamethylcyclohexasiloxane), etc.

[0099] An unsaturated hydrocarbon compound containing a modified group such as an oxoxysilyl group-containing unsaturated hydrocarbon compound not only functions to introduce a modified group at the polymer chain end of the ring-opening copolymer but also functions as a molecular weight regulator. The amount of the unsaturated hydrocarbon compound containing a modified group used can be appropriately selected according to the molecular weight of the ring-opening copolymer to be produced, and is generally in the range of 1 / 100 to 1 / 100000 in terms of molar ratio relative to the monomers used in the copolymerization, preferably 1 / 200 to 1 / 50000, and more preferably 1 / 500 to 1 / 10000.

[0100] The polymerization reaction temperature is not particularly limited, preferably -100 °C or higher, more preferably -50 °C or higher, further preferably 0 °C or higher, and particularly preferably 20 °C or higher. In addition, the upper limit of the polymerization reaction temperature is not particularly limited, preferably less than 100 °C, more preferably less than 90 °C, further preferably less than 80 °C, and particularly preferably less than 70 °C. The polymerization reaction time is also not particularly limited, preferably 1 minute to 72 hours, and more preferably 10 minutes to 20 hours.

[0101] In the ring-opening copolymer obtained by the polymerization reaction, antioxidants such as phenolic stabilizers, phosphorus-based stabilizers, and sulfur-based stabilizers can also be added as needed. The addition amount of the antioxidant can be appropriately determined according to its type and the like. Further, a processing oil can also be blended as needed. In the case where the ring-opening copolymer is obtained in the form of a polymerization solution, in order to recover the ring-opening copolymer from the polymerization solution, a known recovery method can be used. For example, the following methods can be used: a method of separating the solvent by stripping or the like, filtering and separating the solid, and then drying it to obtain a solid ring-opening copolymer; a method of directly devolatilizing the solvent by a twin-screw heating dryer or the like to obtain a solid ring-opening copolymer; a method of reprecipitating with a poor solvent, separating the solvent, filtering and separating the solid, and then drying it to obtain a solid ring-opening copolymer, etc.

[0102] <Rubber composition>

[0103] The rubber composition of the present invention contains the above-mentioned ring-opening copolymer of the present invention. In addition to the above-mentioned ring-opening copolymer of the present invention, the rubber composition of the present invention can also contain compounding agents such as fillers, crosslinking agents, crosslinking accelerators, crosslinking activators, antioxidants, activators, processing oils, plasticizers, and lubricants in required amounts.

[0104] Examples of the filler include carbon black, silica, calcium carbonate, talc, clay, and the like.

[0105] Examples of the carbon black include furnace black, acetylene black, thermal black, channel black, graphite, etc. Among these, furnace black is preferred, and specific examples thereof include SAF, ISAF, ISAF-HS, ISAF-LS, IISAF-HS, HAF, HAF-HS, HAF-LS, FEF, etc. These carbon blacks can be used alone or in combination of two or more.

[0106] The nitrogen adsorption specific surface area (N2SA) of the carbon black is preferably 5 to 200 m 2 / g, more preferably 70 to 120 m 2 / g, and the dibutyl phthalate (DBP) adsorption amount is preferably 5 to 300 ml / 100 g, more preferably 80 to 160 ml / 100 g.

[0107] The silica is not particularly limited, and examples thereof include dry-process silica, wet-process silica, colloidal silica, precipitated silica, etc. In addition, a carbon-silica biphasic filler in which silica is supported on the surface of carbon black can also be used. Among these, wet-process silica mainly composed of hydrous silicic acid is preferred. These silicas can be used alone or in combination of two or more.

[0108] The nitrogen adsorption specific surface area of the silica (measured by the BET method according to ASTM D3037-81) is preferably 50 to 400 m 2 / g, more preferably 100 to 220 m 2 / g. In addition, the pH of the silica is preferably less than pH 7, more preferably pH 5 to 6.9. When in this range, the affinity between the ring-opening copolymer and the silica is particularly good.

[0109] When adding silica to the rubber composition of the present invention, in order to further improve the affinity between the ring-opening copolymer and the silica, it is preferred to further compound a silane coupling agent. Examples of the silane coupling agent include vinyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, bis(3-(triethoxysilyl)propyl)tetrasulfide, bis(3-(triethoxysilyl)propyl)disulfide, etc., and tetrasulfides such as γ-trimethoxysilylpropyl dimethylthiocarbamyl tetrasulfide and γ-trimethoxysilylpropyl benzothiazolyl tetrasulfide described in Japanese Patent Laid-Open No. 6-248116. Tetrasulfides are particularly preferred. These silane coupling agents can be used alone or in combination of two or more. The compounding amount of the silane coupling agent is preferably 0.1 to 30 parts by weight, more preferably 1 to 15 parts by weight, based on 100 parts by weight of the silica.

[0110] From the aspect of further significantly enhancing the effects of the present invention, the content of the filler in the rubber composition of the present invention is preferably 1 to 150 parts by weight, more preferably 10 to 120 parts by weight, still more preferably 15 to 100 parts by weight, and particularly preferably 20 to 80 parts by weight relative to 100 parts by weight of the rubber component in the rubber composition.

[0111] As the crosslinking agent, sulfur such as powdered sulfur, precipitated sulfur, colloidal sulfur, insoluble sulfur, highly dispersed sulfur, etc.; sulfur halides such as sulfur monochloride, sulfur dichloride, etc.; organic peroxides such as dicumyl peroxide, di-tert-butyl peroxide, etc.; quinone dioximes such as p-quinone dioxime, p,p'-dibenzoylquinone dioxime, etc.; organic polyamine compounds such as triethylenetetramine, hexamethylenediamine carbamate, 4,4'-methylenebis(o-chloroaniline), etc.; alkylphenol resins having hydroxymethyl groups, etc. Among these, sulfur is preferred, and powdered sulfur is more preferred. These crosslinking agents can be used alone or in combination of two or more. The compounding amount of the crosslinking agent is preferably 0.1 to 15 parts by weight, more preferably 0.5 to 5 parts by weight relative to 100 parts by weight of the rubber component in the rubber composition.

[0112] As the crosslinking accelerator, for example, sulfenamide-based crosslinking accelerators such as N-cyclohexyl-2-benzothiazole sulfenamide, N-(tert-butyl)-2-benzothiazole sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, N-oxyethylene-2-benzothiazole sulfenamide, N,N'-diisopropyl-2-benzothiazole sulfenamide, etc.; guanidine-based crosslinking accelerators such as 1,3-diphenylguanidine, 1,3-di-o-tolylguanidine, 1-o-tolylbiguanide, etc.; thiourea-based crosslinking accelerators such as diethylthiourea, etc.; thiazole-based crosslinking accelerators such as 2-mercaptobenzothiazole, dibenzothiazole disulfide, zinc salt of 2-mercaptobenzothiazole, etc.; thiuram-based crosslinking accelerators such as tetramethylthiuram monosulfide, tetramethylthiuram disulfide, etc.; dithiocarbamate-based crosslinking accelerators such as sodium dimethyldithiocarbamate, zinc diethyldithiocarbamate, etc.; xanthate-based crosslinking accelerators such as sodium isopropylxanthate, zinc isopropylxanthate, zinc butylxanthate, etc. are exemplified. Particularly preferably, it contains sulfenamide-based crosslinking accelerators, and particularly preferably contains N-(tert-butyl)-2-benzothiazole sulfenamide. These crosslinking accelerators can be used alone or in combination of two or more. The compounding amount of the crosslinking accelerator is preferably 0.1 to 15 parts by weight, more preferably 0.5 to 5 parts by weight relative to 100 parts by weight of the rubber component in the rubber composition.

[0113] As the crosslinking activator, higher fatty acids such as stearic acid, zinc oxide, etc. can be used. The compounding amount of the crosslinking activator can be appropriately selected. However, the compounding amount of the higher fatty acid is preferably 0.05 to 15 parts by weight, more preferably 0.5 to 5 parts by weight, relative to 100 parts by weight of the rubber component in the rubber composition. The compounding amount of zinc oxide is preferably 0.05 to 10 parts by weight, more preferably 0.5 to 3 parts by weight, relative to 100 parts by weight of the rubber component in the rubber composition.

[0114] As the processing oil, mineral oil, synthetic oil can be used. As the mineral oil, aromatic oil, naphthenic oil, paraffin oil, etc. can usually be used.

[0115] Examples of other compounding agents include: activators such as diethylene glycol, polyethylene glycol, silicone oil; tackifiers such as petroleum resin, coumarone resin; wax, etc.

[0116] In addition, the rubber composition of the present invention may contain a rubber other than the above-mentioned ring-opening copolymer of the present invention as the rubber component. Examples of the rubber other than the ring-opening copolymer of the present invention include natural rubber (NR), polyisoprene rubber (IR), emulsion polymerization SBR (styrene-butadiene copolymer rubber), solution polymerization random SBR (bonded styrene 5 to 50% by weight, 1,2-bond content of the butadiene part 10 to 80%), high trans SBR (trans bond content of the butadiene part 70 to 95%), low cis BR (polybutadiene rubber), high cis BR, high trans BR (trans bond content of the butadiene part 70 to 95%), ethylene-propylene-diene rubber (EPDM), styrene-isoprene copolymer rubber, butadiene-isoprene copolymer rubber, emulsion polymerization styrene-acrylonitrile-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, high vinyl SBR-low vinyl SBR block copolymer rubber, polyisoprene-SBR block copolymer rubber, polystyrene-polybutadiene-polystyrene block copolymer, acrylic rubber, epichlorohydrin rubber, fluororubber, silicone rubber, ethylene-propylene rubber, polyurethane rubber, etc. It is particularly preferred to use NR, BR, IR, EPDM, SBR, and particularly preferably solution polymerization random SBR. These rubbers can be used alone or in combination of two or more.

[0117] From the aspect of being able to make the action effect of the present invention more remarkable, the content ratio of the ring-opening copolymer in the rubber composition of the present invention is preferably 50% by weight or more, more preferably 60% by weight or more, and particularly preferably 70% by weight or more, relative to the total amount of the rubber components.

[0118] The rubber composition of the present invention can be obtained by kneading each component according to a conventional method. For example, after kneading compounding agents other than the crosslinking agent and crosslinking accelerator with a rubber component such as a ring-opening copolymer, the crosslinking agent and crosslinking accelerator can be mixed in the kneaded product to obtain the rubber composition. The kneading temperature of the compounding agents other than the crosslinking agent and crosslinking accelerator and the rubber component such as the ring-opening copolymer is preferably 20 to 200 °C, more preferably 30 to 180 °C, and the kneading time is preferably 30 seconds to 30 minutes. The mixing of the crosslinking agent and crosslinking accelerator is usually carried out after cooling to 100 °C or lower, preferably after cooling to 80 °C or lower.

[0119] <Rubber crosslinked product>

[0120] The rubber crosslinked product of the present invention is obtained by crosslinking the above-mentioned rubber composition of the present invention.

[0121] The rubber crosslinked product of the present invention can be manufactured in the following manner: using the rubber composition of the present invention, molding is carried out through a molding machine corresponding to a desired shape, such as an extruder, injection molding machine, compressor, roll, etc., and the crosslinking reaction is carried out by heating to form a rubber crosslinked product and fix the shape. In this case, crosslinking can be carried out after pre-molding, or crosslinking can be carried out simultaneously with molding. The molding temperature is usually 10 to 200 °C, preferably 25 to 120 °C. The crosslinking temperature is usually 100 to 200 °C, preferably 130 to 190 °C, and the crosslinking time is usually 1 minute to 24 hours, preferably 2 minutes to 12 hours, and particularly preferably 3 minutes to 6 hours.

[0122] In addition, depending on the shape, size, etc. of the rubber crosslinked product, sometimes even though the surface has been crosslinked, the inside has not been sufficiently crosslinked, so it can be further heated to carry out secondary crosslinking.

[0123] As the heating method, any of the usual methods used in the crosslinking of rubber, such as press heating, steam heating, oven heating, hot air heating, etc., can be appropriately selected.

[0124] The rubber crosslinked product of the present invention thus obtained is a rubber crosslinked product obtained by using the above-mentioned ring-opening copolymer of the present invention, and thus has excellent balance in mechanical strength, wet grip, and low heat generation. The rubber crosslinked product of the present invention can exhibit such characteristics and be used for, for example: materials for various parts of tires such as the crown, tread base, carcass, sidewall, and bead of tires; materials for hoses, belts, gaskets, anti-vibration rubbers, and other various industrial products; impact resistance improvers for resins; resin film buffers; soles; rubber shoes; golf balls; toys, etc. In particular, the rubber crosslinked product of the present invention can be preferably used for various parts of tires such as the tread, carcass, sidewall, and bead in all-season tires, high-performance tires, and studless tires.

[0125] Examples

[0126] Hereinafter, based on detailed examples, the present invention will be further described, but the present invention is not limited to these examples. In addition, hereinafter, unless otherwise specified, "parts" are based on weight. Furthermore, various tests and evaluations are carried out according to the following methods.

[0127] <Molecular weight>

[0128] The number-average molecular weight (Mn), weight-average molecular weight (Mw), and molecular weight distribution (Mw / Mn) of the polymer were measured in terms of polystyrene conversion values by gel permeation chromatography (GPC) using tetrahydrofuran as a solvent. An HLC-8320GPC (manufactured by Tosoh Corporation) was used as the measuring device. The measurement was carried out using four TSKgel SuperMultipore HZ-H (manufactured by Tosoh Corporation) columns connected in series under the conditions of a flow rate of 0.35 ml / minute, a sample injection volume of 10 μl, and a column temperature of 40°C.

[0129] <Monomer composition ratio>

[0130] The monomer composition ratio of the polymer was determined by 1 1H-NMR spectroscopy. That is, 1H-NMR measurement was carried out using deuterated chloroform as a solvent, and it was determined based on the integration ratio of the signals at 5.0 to 5.5 ppm from the double bond and the integration ratio of the signals at 2.3 to 3.0 ppm from the norbornene compound. 1 1

[0131] <Cis / trans ratio of main-chain double bonds>

[0132] The cis / trans ratio of the main-chain double bonds of the polymer was determined by 13 13C-NMR spectroscopy.

[0133] <Glass transition temperature (Tg)>

[0134] The glass transition temperature (Tg) of the polymer was measured using a differential scanning calorimeter (DSC) at a heating rate of 10°C / minute.

[0135] <Mechanical strength>

[0136] A sheet-like rubber crosslinked product is produced by compression crosslinking a rubber composition at 160 °C for 20 minutes. The rubber crosslinked product is punched into a dumbbell shape No. 6 specified in JIS K6251:2010 in a direction parallel to the grain direction, thereby obtaining a dumbbell-shaped test piece. Then, for the obtained dumbbell-shaped test piece, a tensile strength test is carried out at 23 °C and 500 mm / min according to JIS K6251:2010 using a tensile testing machine (product name "TENSOMETER10K", manufactured by Alpha Technology Co., Ltd.), and the tensile strength is measured. Then, based on the obtained measurement results, an index is calculated with the measured value of the sample in Comparative Example 1 set to 100. The higher the mechanical strength, the larger the index. When the index is 101 or more, it can be determined that the mechanical strength is excellent.

[0137] <Wet grip performance>

[0138] A test piece is produced by compression crosslinking a rubber composition at 160 °C for 20 minutes. For the obtained test piece, tanδ at 0 °C is measured using ARES manufactured by Rheometrics Co., Ltd. under the conditions of dynamic strain of 0.5% and 10 Hz. Then, based on the obtained measurement results, an index is calculated with the measured value of the sample in Comparative Example 1 set to 100. The higher the wet grip performance, the larger the index. When the index is 90 or more, it can be determined that the wet grip performance is sufficient.

[0139] <Low heat generation property>

[0140] A test piece is produced by compression crosslinking a rubber composition at 160 °C for 20 minutes. For the obtained test piece, tanδ at 60 °C is measured using ARES manufactured by Rheometrics Co., Ltd. under the conditions of dynamic strain of 2.0% and 10 Hz. Then, based on the obtained measurement results, an index is calculated with the measured value of the sample in Comparative Example 1 set to 100. The more excellent the low heat generation property, the larger the index. When the index is 101 or more, it can be determined that the low heat generation property is excellent.

[0141] <Abrasion resistance>

[0142] Using a metal mold, a rubber composition was compression-molded at 160 °C for 20 minutes while being pressurized to obtain a rubber crosslinked product for high resilience materials in a cylindrical shape with a diameter of 16 mm and a thickness of 6 mm. Then, for the obtained cylindrical rubber crosslinked product for high resilience materials, a DIN abrasion tester (trade name “AB-6110”, manufactured by Ueshima Seisakusho Co., Ltd.) was used as the testing machine, and according to JIS K6264-2:2005, the relative abrasion volume was measured under the conditions of test method A, an applied force of 10 N, a friction distance of 40 m, 23 °C, and a reference test piece D1. Then, based on the obtained measurement results, an index was calculated with the measured value of the sample of Comparative Example 1 set as 100. The more excellent the abrasion resistance, the larger the index, and when the index is 90 or more, it can be determined that the abrasion resistance is sufficient.

[0143] <<Example 1>>

[0144] In a nitrogen atmosphere, 120 parts of cyclooctene (COE), 80 parts of dicyclopentadiene (DCPD) as a norbornene compound with three or more rings, 1194 parts of cyclohexane, and 0.20 parts of 1-hexene were added to a glass reaction vessel equipped with a stirrer. Next, 0.028 parts of dichloro[1,3-bis(2,4,6-trimethylphenyl)-2-imidazolidinylidene](benzylidene)(tricyclohexylphosphine)ruthenium(II) dissolved in 10 parts of toluene was added, and a polymerization reaction was carried out at room temperature for 4 hours. After the polymerization reaction, an excess of vinyl ethyl ether was added to terminate the polymerization.

[0145] The polymerization solution was poured into a large excess of methanol containing 2,6-di-tert-butyl-p-cresol (BHT) to recover the precipitated polymer. After washing with methanol, it was vacuum-dried at 50 °C for 3 days to obtain 200 parts of a COE / DCPD ring-opening copolymer. The weight-average molecular weight (Mw) of the obtained COE / DCPD ring-opening copolymer was 248,000, the content ratio of the structural unit derived from cyclooctene was 60% by weight, the content ratio of the structural unit derived from the norbornene compound with three or more rings (DCPD) was 40% by weight, the trans bond ratio was 64% (cis / trans ratio was 36% / 64%), and the glass transition temperature (Tg) was -45 °C.

[0146] Plasticate 100 parts of the obtained COE / DCPD ring-opening copolymer using a Banbury mixer with a volume of 250 ml. Add 50 parts of carbon black (trade name "SEAST9H", manufactured by Tokai Carbon Co., Ltd.), 3 parts of zinc oxide (zinc white No. 1), 2.0 parts of stearic acid (trade name "SA-300", manufactured by Adeka Corporation), and 2.0 parts of N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (trade name "NOCRAC6C", manufactured by Ouchi Shinko Chemical Industry Co., Ltd., antioxidant). Mix at an initial temperature of 80°C for 4 minutes, and then discharge the rubber composition from the Banbury mixer. The temperature of the rubber composition at the end of mixing is 160°C. Next, mix the obtained rubber composition with 1.75 parts of sulfur and 1 part of N-cyclohexylbenzothiazole-2-sulfenamide (trade name "NOCCELER CZ-G (CZ)", manufactured by Ouchi Shinko Chemical Industry Co., Ltd., crosslinking accelerator) using an open roll at 50°C, and then take out the sheet-like rubber composition. Evaluate the mechanical strength, wet grip, low heat generation, and abrasion resistance of the obtained rubber composition according to the above method. The results are shown in Table 1. In addition, these evaluations are expressed as indices based on the test piece of Comparative Example 1 as the reference sample (index 100).

[0147] 《Example 2》

[0148] In Example 2, tetracyclo[6.2.1.1 3,6 .0 2,7 dodec-4-ene (TCD) is used as the norbornene compound having three or more rings. Change the compounds used for polymerization as described in Table 1, and otherwise carry out the same procedures as in Example 1 to obtain a COE / TCD ring-opening copolymer. The physical properties of the obtained COE / TCD ring-opening copolymer are as described in Table 1. Then, use the obtained COE / TCD ring-opening copolymer, and otherwise carry out the same procedures as in Example 1 to obtain a rubber crosslink, and carry out the evaluation in the same manner as in Example 1. The results are shown in Table 1.

[0149] 《Example 3》

[0150] In Example 3, 1,4-methano-1,4,4a,9a-tetrahydro-9H-fluorene (MTHF) is used as the norbornene compound having three or more rings. Change the compounds used for polymerization as described in Table 1, and otherwise carry out the same procedures as in Example 1 to obtain a COE / MTHF ring-opening copolymer. The physical properties of the obtained COE / MTHF ring-opening copolymer are as described in Table 1. Then, use the obtained COE / MTHF ring-opening copolymer, and otherwise carry out the same procedures as in Example 1 to obtain a rubber crosslink, and carry out the evaluation in the same manner as in Example 1. The results are shown in Table 1.

[0151] Examples 4 to 6

[0152] The compounds used for polymerization were changed as described in Table 1, and otherwise, the procedure was the same as in Example 1 to obtain a COE / DCPD ring-opening copolymer. The physical properties of the obtained COE / DCPD ring-opening copolymer are as described in Table 1. Then, using the obtained COE / DCPD ring-opening copolymer, and otherwise, the procedure was the same as in Example 1 to obtain a rubber crosslinked product, which was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0153] Comparative Example 1

[0154] In Comparative Example 1, cyclopentene (CPE) was used instead of cyclooctene (COE). The compounds used for polymerization were changed as described in Table 1, and otherwise, the procedure was the same as in Example 1 to obtain a CPE / DCPD ring-opening copolymer. The physical properties of the obtained CPE / DCPD ring-opening copolymer are as described in Table 1. Then, using the obtained CPE / DCPD ring-opening copolymer, and otherwise, the procedure was the same as in Example 1 to obtain a rubber crosslinked product, which was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0155] Comparative Example 2

[0156] In Comparative Example 2, 2-norbornene (NB) was used instead of a norbornene compound having three or more rings. The compounds used for polymerization were changed as described in Table 1, and otherwise, the procedure was the same as in Example 1 to obtain a COE / NB ring-opening copolymer. The physical properties of the obtained COE / NB ring-opening copolymer are as described in Table 1. Then, using the obtained COE / NB ring-opening copolymer, and otherwise, the procedure was the same as in Example 1 to obtain a rubber crosslinked product, which was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0157] Comparative Example 3

[0158] In Comparative Example 3, only cyclooctene (COE) was used as a monomer. The compounds used for polymerization were changed as described in Table 1, and otherwise, the procedure was the same as in Example 1 to obtain a COE ring-opening polymer. The physical properties of the obtained COE ring-opening polymer are as described in Table 1. Then, using the obtained COE ring-opening polymer, and otherwise, the procedure was the same as in Example 1 to obtain a rubber crosslinked product, which was evaluated in the same manner as in Example 1. The results are shown in Table 1.

[0159] [Table 1]

[0160]

[0161] As shown in Table 1, ring-opening copolymers containing structural units derived from cyclooctene and structural units derived from norbornene compounds with three or more rings can form rubber crosslinks with excellent balance in mechanical strength, wet grip, and low heat generation (Examples 1 to 6).

[0162] On the other hand, a ring-opening copolymer containing structural units derived from cyclopentane instead of structural units derived from cyclooctene forms a rubber crosslink with poor low heat generation (Comparative Example 1).

[0163] In addition, a ring-opening copolymer containing structural units derived from 2-norbornene instead of structural units derived from norbornene compounds with three or more rings forms a rubber crosslink with poor mechanical strength (Comparative Example 2).

[0164] Furthermore, a ring-opening copolymer not containing structural units derived from norbornene compounds with three or more rings forms a rubber crosslink with poor mechanical strength and wet grip (Comparative Example 3).

Claims

1. An open-ring copolymer comprising structural units derived from cyclooctene and structural units derived from a norbornene compound having three or more rings.

2. The open-ring copolymer according to claim 1, wherein the content ratio of the structural units derived from cyclooctene is 10 to 95% by weight, and the content ratio of the structural units derived from the norbornene compound having three or more rings is 5 to 90% by weight, based on all the repeating structural units in the open-ring copolymer.

3. The open-loop copolymer according to claim 1 or 2, wherein, The norbornene compound having three or more rings is a norbornene compound having 3 to 6 ring structures.

4. The open-loop copolymer according to claim 1 or 2, wherein, The norbornene compound having three or more rings is a compound represented by the following general formula (1) and / or a compound represented by the following general formula (2), In the general formula (1), R 1 and R 2 each independently represent: a hydrogen atom; a halogen atom; a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent; or a substituent containing a silicon atom, an oxygen atom or a nitrogen atom, R 1 and R 2 may bond to each other to form a ring, R 3 represents a divalent hydrocarbon group having 1 to 20 carbon atoms which may have a substituent, In the general formula (2), R 4 ~R 7 each independently represents: a hydrogen atom; a halogen atom; a hydrocarbon group having 1 to 20 carbon atoms which may have a substituent; or a substituent containing a silicon atom, an oxygen atom or a nitrogen atom, R 4 and R 6 , or R 4 and R 5 can bond to each other to form a ring; and / or R 6 and R 7 can bond to each other to form a ring, and n is 1 or 2.

5. The ring-opening copolymer according to any one of claims 1 to 4, wherein the weight-average molecular weight (Mw) of the open-ring copolymer is 10,000 to 1,000,000, the cis / trans ratio is 90 / 10 to 5 / 95, and the glass transition temperature (Tg) is -100 to 20°C.

6. A rubber composition comprising the open-ring copolymer according to any one of claims 1 to 5.

7. The rubber composition according to claim 6, wherein, The rubber composition further comprises a filler.

8. The rubber composition according to claim 6 or 7, wherein, The rubber composition further comprises a crosslinking agent.

9. A rubber crosslinked product obtained by crosslinking the rubber composition according to any one of claims 6 to 8.

10. A tire comprising the rubber crosslinked product according to claim 9.

Images