JP2019081839A - Rubber crosslinked product - Google Patents

Abstract

To provide a rubber crosslinked product having excellent compression set resistance, obtained by using a cyclopentene ring-opened polymer.SOLUTION: A rubber crosslinked product is obtained by cross-linking a polymer composition containing 20-200 pts.wt. of carbon black with respect to 100 pts.wt. of a rubber component containing a cyclopentene ring-opened polymer having a branched structure. After the rubber crosslinked product in a 25% compression state is held at 100°C for 72 hours, the rubber crosslinked product shows a permanent compression set of 35% or less.SELECTED DRAWING: None

Description

  The present invention relates to a rubber crosslinked product obtained using a cyclopentene ring-opened polymer, and more particularly to a rubber crosslinked product excellent in compression set resistance obtained using a cyclopentene ring-opened polymer.

  Conventionally, butadiene rubber is widely used as a rubber material for forming various rubber components. Butadiene, which is a raw material of butadiene rubber, is produced as a by-product in the production of ethylene by cracking naphtha, but in recent years, the method of using natural gas such as ethane as a raw material has been expanded as a production method of ethylene. As a result, a decrease in butadiene production is expected. Therefore, various studies are underway on using a synthetic rubber which does not use butadiene as a raw material as a substitute material for butadiene rubber.

  One kind of synthetic rubber which has been studied as a substitute material for butadiene rubber is a cyclopentene ring-opened polymer which can be obtained by ring-opening polymerization of cyclopentene. For example, Patent Document 1 discloses a rubber composition for a tire containing a cyclopentene ring-opened polymer, a solution-polymerized styrene-butadiene rubber, and silica. According to the technique of Patent Document 1, although it is possible to give a rubber cross-linked product excellent in low heat buildup, compression set resistance is not necessarily sufficient, and therefore, for tire applications where low heat buildup is required. Although suitable, they were not necessarily suitable for applications requiring compression set resistance.

WO 2016/060267

  The present invention has been made in view of such circumstances, and it is an object of the present invention to provide a rubber crosslinked product having excellent compression set resistance, which is obtained using a cyclopentene ring-opened polymer.

  As a result of intensive studies to achieve the above object, the present inventors use a cyclopentene ring-opened polymer having a branched structure, and contain a cyclopentene ring-opened polymer having such a branched structure. It has been found that the above object can be achieved by a rubber cross-linked product obtained by cross-linking a polymer composition comprising a predetermined amount of carbon black blended with a rubber component to be treated, and the present invention has been completed.

  That is, according to the present invention, a rubber obtained by crosslinking a polymer composition containing 20 to 200 parts by weight of carbon black relative to 100 parts by weight of a rubber component containing a cyclopentene ring-opening polymer having a branched structure A cross-linked rubber is provided, which has a compression set of 35% or less after holding at 100 ° C. for 72 hours in a 25% -compressed state.

（上記式（I）中、水素原子は炭素数１〜６のアルキル基で置換されていてもよい。）

（上記式（II）中、水素原子は炭素数１〜６のアルキル基で置換されていてもよい。）

（上記式（III）中、水素原子は炭素数１〜６のアルキル基で置換されていてもよい。）

（上記式（IV）中、水素原子は炭素数１〜６のアルキル基で置換されていてもよい。） In the present invention, the cyclopentene ring-opening polymer having the branched structure starts from a branched structural unit represented by the following formula (I), the following formula (II), the following formula (III) or the following formula (IV) It is preferable to have a branched structure.

(In the above formula (I), a hydrogen atom may be substituted with an alkyl group having 1 to 6 carbon atoms.)

(In the above formula (II), a hydrogen atom may be substituted with an alkyl group having 1 to 6 carbon atoms.)

(In the above formula (III), a hydrogen atom may be substituted with an alkyl group having 1 to 6 carbon atoms.)

(In the above formula (IV), a hydrogen atom may be substituted with an alkyl group having 1 to 6 carbon atoms.)

  According to the present invention, it is possible to provide a rubber cross-linked product which is excellent in compression set resistance, and which can be suitably used for applications where compression set resistance is required.

  The crosslinked rubber product of the present invention is obtained by crosslinking a polymer composition containing 20 to 200 parts by weight of carbon black with respect to 100 parts by weight of a rubber component containing a cyclopentene ring-opened polymer having a branched structure, It is a rubber cross-linked product with a compression set of 35% or less after holding at 100 ° C. for 72 hours in a state of 25% compression.

  The rubber component used in the present invention contains a cyclopentene ring-opened polymer having a branched structure. The cyclopentene ring-opened polymer having a branched structure used in the present invention contains a repeating unit formed by ring-opening polymerization of cyclopentene as a repeating unit constituting the main chain, and a heavy chain having a branched structure in the main chain It is union.

  In the cyclopentene ring-opened polymer having a branched structure used in the present invention, the content ratio of repeating units formed by ring-opening polymerization of cyclopentene is preferably at least 86 mol%, more preferably 92 mol% with respect to all repeating units. The upper limit is preferably 99.99 mol% or less, more preferably 99.95 mol% or less, and still more preferably 99.90 mol% or less.

  Moreover, it is preferable that the cyclopentene ring-opened polymer which has a branched structure used by this invention has a branched structural unit for introduce | transducing a branched structure in a polymer chain. The branched structural unit may be a structural unit derived from a monomer capable of ring-opening copolymerization with cyclopentene and capable of forming a branched structure, and is not particularly limited, but a ring having one double bond A structural unit derived from a polycyclic diolefin compound having at least two structures, or a structural unit derived from a cyclic olefin compound having a ring structure having one double bond and a vinyl group is preferable.

  By introducing, as a branched structural unit, a structural unit derived from a polycyclic diolefin compound having at least two ring structures having one double bond (hereinafter, appropriately referred to as “polycyclic diolefin compound”) In the polymer chain, a 4-branched structure starting from such a structural unit can be introduced. In addition, a structural unit derived from a cyclic olefin compound having a cyclic structure having one double bond and a vinyl group as the branched structural unit (hereinafter referred to as “vinyl group-containing cyclic olefin compound” as appropriate) is introduced. By doing this, it is possible to introduce into the polymer chain a three-branched structure starting from such a structural unit. Among these, from the viewpoint that a four-branched structure can be introduced into the polymer chain, it is preferable to introduce a structural unit derived from a polycyclic diolefin compound using a polycyclic diolefin compound. That is, as the cyclopentene ring-opening polymer having a branched structure used in the present invention, one having a 4-branched structure is preferable, and by using a 4-branched structure, the obtained rubber cross-linked product has compression set resistance. It can be excellent.

上記式（１）中、Ｒ^１、Ｒ^２は、炭素数１〜６のアルキレン基であり、ｎは０〜２の整数であり、上記式（１）中、水素原子は炭素数１〜６のアルキル基で置換されていてもよい。また、上記式（１）で表される化合物は、シクロペンテンと開環共重合した際に、上記式（１ａ）で表される分岐構造単位を与えることとなるものであり、上記式（１ａ）中、Ｒ^１、Ｒ^２、ｎは上記式（１）と同じであり、上記式（１ａ）中、水素原子は炭素数１〜６のアルキル基で置換されていてもよい。

上記式（２）〜（５）中、水素原子は炭素数１〜６のアルキル基で置換されていてもよい。また、上記式（２）〜（５）で表される化合物は、シクロペンテンと開環共重合した際に、それぞれ、上記式（２ａ）〜（５ａ）で表される分岐構造単位を与えることとなるものであり、上記式（２ａ）〜（５ａ）中、水素原子は炭素数１〜６のアルキル基で置換されていてもよい。 The multicyclic diolefin compound for forming the structural unit derived from the multicyclic diolefin compound is not particularly limited, but a compound represented by the following formula (1) or the following formulas (2) to (5) The compound represented is mentioned.

In the formula ^(1), R 1, ^{R 2} is an alkylene group having 1 to 6 carbon atoms, n is an integer of 0 to 2, in the formula (1), a hydrogen atom is 1 to 6 carbon atoms It may be substituted by the alkyl group of Further, the compound represented by the above formula (1) is to give a branched structural unit represented by the above formula (1a) when ring-opening copolymerization with cyclopentene is carried out, and the above formula (1a) Among them, R ¹ , R ² and n are the same as in the above formula (1), and in the above formula (1a), a hydrogen atom may be substituted by an alkyl group having 1 to 6 carbon atoms.

In the above formulas (2) to (5), a hydrogen atom may be substituted by an alkyl group having 1 to 6 carbon atoms. The compounds represented by the above formulas (2) to (5) give branch structural units represented by the above formulas (2a) to (5a) when ring-opening copolymerization with cyclopentene, respectively. In the above formulas (2a) to (5a), the hydrogen atom may be substituted by an alkyl group having 1 to 6 carbon atoms.

上記式（６）〜（９）中、水素原子は炭素数１〜６のアルキル基で置換されていてもよい。また、上記式（６）〜（９）で表される化合物は、シクロペンテンと開環共重合した際に、それぞれ、上記式（６ａ）〜（９ａ）で表される分岐構造単位を与えることとなるものであり、上記式（６ａ）〜（９ａ）中、水素原子は炭素数１〜６のアルキル基で置換されていてもよい。 Moreover, as a specific example of a compound represented by said Formula (1), the compound represented by following formula (6)-(9) is mentioned, for example.

In the above formulas (6) to (9), a hydrogen atom may be substituted by an alkyl group having 1 to 6 carbon atoms. The compounds represented by the above formulas (6) to (9) give branch structural units represented by the above formulas (6a) to (9a), respectively, when ring-opening copolymerization with cyclopentene is carried out. In the above formulas (6a) to (9a), the hydrogen atom may be substituted by an alkyl group having 1 to 6 carbon atoms.

  Among the above-described compounds, it is preferable to use a compound represented by the above formula (3), the above formula (6) or the above formula (7) from the viewpoint that a branched structure can be more appropriately formed. That is, as a cyclopentene ring-opening polymer having a branched structure used in the present invention, one having a branched structural unit represented by the above formula (3a), the above formula (6a) or the above formula (7a) as a branched structural unit Is preferred.

上記式（１０）中、水素原子は炭素数１〜６のアルキル基で置換されていてもよい。また、上記式（１０）で表される化合物は、シクロペンテンと開環共重合した際に、上記式（１０ａ）で表される分岐構造単位を与えることとなるものであり、上記式（１０ａ）中、水素原子は炭素数１〜６のアルキル基で置換されていてもよい。 Also, the vinyl group-containing cyclic olefin compound for forming a structural unit derived from a vinyl group-containing cyclic olefin compound is not particularly limited, but it is a monocyclic having a vinyl group such as 4-vinylcyclopentene or 5-vinylcyclooctene. Olefins; norbornenes having a vinyl group such as 5-vinyl-2-norbornene, 5-propenyl-2-norbornene, 5-styryl-2-norbornene, and the like. In these compounds, a hydrogen atom may be substituted by an alkyl group having 1 to 6 carbon atoms. Among these, 5-vinyl-2-norbornene represented by the following formula (10) (in which a hydrogen atom is substituted with an alkyl group having 1 to 6 carbon atoms) is also possible from the viewpoint that a branched structure can be more appropriately formed. Is preferred.

In said formula (10), the hydrogen atom may be substituted by the C1-C6 alkyl group. Further, the compound represented by the above formula (10) gives a branched structural unit represented by the above formula (10a) when ring-opening copolymerization with cyclopentene is carried out, and the above formula (10a) Among them, a hydrogen atom may be substituted by an alkyl group having 1 to 6 carbon atoms.

  Moreover, as a compound for forming a branched structural unit, as a compound capable of introducing a three-branched structure other than the above-mentioned compounds, 1,2,4-trivinylcyclohexane, 1,3,5-trivinylcyclohexane, and the like. A compound having three vinyl groups such as vinylcyclohexane can also be used. Alternatively, a branched structure having four or more branches may be introduced by using a compound having four or more vinyl groups such as divinylbenzene oligomer, 1,2-polybutadiene oligomer, and the like.

  The content of the branched structural unit in the cyclopentene ring-opened polymer having a branched structure used in the present invention is preferably 0.01 mol% or more, more preferably 0.05 mol% or more, based on all repeating units. More preferably, it is 0.1 mol% or more, and the upper limit thereof is preferably 4 mol% or less, more preferably 3 mol% or less, still more preferably 2.6 mol% or less. By setting the content ratio of the branched structural unit in the above range, while the gelation of the obtained cyclopentene ring-opened polymer having a branched structure is appropriately prevented, the compression set resistance in the rubber crosslinked product is further enhanced. It can be done.

  Further, the cyclopentene ring-opened polymer having a branched structure used in the present invention is a single monomer capable of copolymerizing with cyclopentene and a monomer capable of forming a branched structure as long as the properties as a cyclopentene ring-opened polymer are maintained. It may contain a repeating unit derived from the body. The content ratio of repeating units derived from other copolymerizable monomers is preferably 10 mol% or less, more preferably 5 mol% or less, more preferably 10 mol% or less, based on all repeating units. It is 1 mol% or less.

Other monomers copolymerizable with cyclopentene include monocyclic olefins other than cyclopentene, monocyclic dienes, monocyclic trienes, polycyclic cyclic olefins, polycyclic cyclic olefins, polycyclic cyclic dienes, and polycyclic cyclic trienes. . Examples of monocyclic olefins other than cyclopentene include cyclooctene. Examples of monocyclic dienes include 1,5-cyclooctadiene. Examples of monocyclic trienes include 1,5,9-cyclododecatriene. Moreover, as a polycyclic cyclic olefin, a polycyclic cyclic diene, and a polycyclic cyclic triene, 2-norbornene, dicyclopentadiene, 1,4-methano-1,4,4a, 9a-tetrahydro-9H-fluorene , Tetracyclo [6.2.1.1 ^{3, 6} . Examples of norbornene compounds such as 0 ^2,7 ] dodec-4-ene and the like. The cyclopentene and the other monomers copolymerizable with the above cyclopentene may be substituted or unsubstituted. Moreover, the other monomer copolymerizable with the said cyclopentene may be used individually by 1 type, or may be used combining 2 or more types.

  The molecular weight of the cyclopentene ring-opened polymer having a branched structure is not particularly limited, but it is 100,000 to 1,000,000 as a value of weight average molecular weight (Mw) in terms of polystyrene measured by gel permeation chromatography. Is preferable, 150,000 to 900,000 is preferable, and 200,000 to 800,000 is more preferable. When the cyclopentene ring-opened polymer having a branched structure has such a molecular weight, the mechanical properties of the rubber cross-linked product can be made more excellent.

  The ratio (Mw / Mn) of polystyrene-equivalent number average molecular weight (Mn) to weight average molecular weight (Mw), as measured by gel permeation chromatography, of the cyclopentene ring-opened polymer having a branched structure is not particularly limited. Is usually 4.0 or less, preferably 3.5 or less, more preferably 3.0 or less. By having such Mw / Mn, the mechanical properties of the cross-linked rubber can be made more excellent.

  The cis / trans ratio of the double bonds present in the repeating unit constituting the cyclopentene ring-opened polymer having a branched structure is not particularly limited, but is usually set in the range of 10/90 to 90/10. From the viewpoint of making the rubber crosslinked product more excellent in low temperature properties, the range of 90/10 to 51/49 is preferable, and the range of 90/10 to 55/45 is more preferable. Alternatively, from the viewpoint of making the rubber cross-linked product more excellent in fracture strength properties, it is preferably in the range of 10/90 to 49/51, and more preferably in the range of 10/90 to 45/55. .

  The method for adjusting the cis / trans ratio of the cyclopentene ring-opened polymer having a branched structure is not particularly limited. For example, a monomer mixture containing cyclopentene and a monomer capable of forming a branched structure is polymerized. A method of controlling the polymerization conditions in obtaining a cyclopentene ring-opened polymer having a branched structure may, for example, be mentioned. For example, the higher the polymerization temperature when polymerizing a monomer mixture containing cyclopentene and a monomer capable of forming a branched structure, the higher the trans ratio, and the monomer concentration in the polymerization solution. The lower the ratio, the higher the transformer ratio.

  The glass transition temperature of the cyclopentene ring-opened polymer having a branched structure is not particularly limited, but is preferably −90 ° C. or less, more preferably −95 ° C., from the viewpoint of exhibiting excellent properties at low temperatures. Below, it is still more preferably below -98 ° C. The glass transition temperature of the cyclopentene ring-opened polymer having a branched structure can be adjusted, for example, by adjusting the cis / trans ratio or the like of double bonds present in the repeating unit.

  The cyclopentene ring-opening polymer having a branched structure may have a molecular structure consisting of only carbon atoms and hydrogen atoms, but may contain atoms other than carbon atoms and hydrogen atoms in the molecular structure. More specifically, a modifying group containing an atom selected from the group consisting of atoms of group 15 of the periodic table, atoms of group 16 of the periodic table, and silicon atoms may be contained.

  As such a modifying group, a modifying group containing an atom selected from the group consisting of a nitrogen atom, an oxygen atom, a phosphorus atom, a sulfur atom and a silicon atom is preferable, and among these, a nitrogen atom and an oxygen atom And modifying groups containing an atom selected from the group consisting of silicon atoms are more preferred, and modifying groups containing silicon atoms are even more preferred.

  Examples of the nitrogen atom-containing modifying group include an amino group, a pyridyl group, an imino group, an amido group, a nitro group, a urethane bonding group, or a hydrocarbon group containing these groups. Examples of the modifying group containing an oxygen atom include a hydroxyl group, a carboxylic acid group, an ether group, an ester group, a carbonyl group, an aldehyde group, an epoxy group, or a hydrocarbon group containing these groups. Examples of the modifying group containing a silicon atom include an alkylsilyl group, an oxysilyl group, or a hydrocarbon group containing these groups. As the modifying group containing a phosphorus atom, a phosphoric acid group, a phosphino group, or a hydrocarbon group containing these groups is exemplified. Examples of the modifying group containing a sulfur atom include a sulfonyl group, a thiol group, a thioether group, or a hydrocarbon group containing these groups. Further, the modifying group may be a modifying group containing a plurality of the groups described above. Among these, as a specific example of a particularly preferable modifying group, carbonized including an amino group, pyridyl group, imino group, amido group, hydroxyl group, carboxylic acid group, aldehyde group, epoxy group, oxysilyl group, or these groups A hydrogen group is mentioned, and an oxysilyl group is particularly preferred. In addition, an oxysilyl group means group which has a silicon-oxygen bond.

  Specific examples of the oxysilyl group include an alkoxysilyl group, an aryloxysilyl group, an acyloxy group, an alkylsiloxysilyl group, an arylsiloxysilyl group, and a hydroxysilyl group. Among these, an alkoxysilyl group is preferable from the viewpoint that its introduction effect is high.

  The alkoxysilyl group is a group formed by bonding one or more alkoxy groups to a silicon atom, and specific examples thereof include trimethoxysilyl group, (dimethoxy) (methyl) silyl group, (methoxy) (dimethyl) silyl Group, triethoxysilyl group, (diethoxy) (methyl) silyl group, (ethoxy) (dimethyl) silyl group, (dimethoxy) (ethoxy) silyl group, (methoxy) (diethoxy) silyl group, tripropoxysilyl group, tributoxy A silyl group etc. are mentioned.

  The aryloxysilyl group is a group formed by bonding one or more aryloxy groups to a silicon atom, and specific examples thereof include triphenoxysilyl group, (diphenoxy) (methyl) silyl group, (phenoxy) (dimethyl) Examples include silyl group, (diphenoxy) (ethoxy) silyl group, and (phenoxy) (diethoxy) silyl group. Among these, the (diphenoxy) (ethoxy) silyl group and the (phenoxy) (diethoxy) silyl group are also classified as alkoxysilyl groups because they have alkoxy groups in addition to aryloxy groups.

  The acyloxysilyl group is a group formed by combining one or more acyloxy groups with a silicon atom, and specific examples thereof include a triacyloxysilyl group, (diacyloxy) (methyl) silyl group, (acyloxy) (dimethyl) A silyl group etc. are mentioned.

  The alkylsiloxysilyl group is a group formed by combining one or more alkylsiloxy groups with a silicon atom, and specific examples thereof include a tris (trimethylsiloxy) silyl group, a trimethylsiloxy (dimethyl) silyl group, a triethylsiloxy ( Diethyl) silyl group, tris (dimethylsiloxy) silyl group and the like can be mentioned.

  The arylsiloxysilyl group is a group formed by combining one or more arylsiloxy groups with a silicon atom, and specific examples thereof include tris (triphenylsiloxy) silyl group, triphenylsiloxy (dimethyl) silyl group, tris (Diphenylsiloxy) silyl group etc. are mentioned.

  The hydroxysilyl group is a group formed by bonding one or more hydroxy groups to a silicon atom, and specific examples thereof include a trihydroxysilyl group, (dihydroxy) (methyl) silyl group, (hydroxy) (dimethyl) silyl group , (Dihydroxy) (ethoxy) silyl group, (hydroxy) (diethoxy) silyl group and the like. Among these, the (dihydroxy) (ethoxy) silyl group and the (hydroxy) (diethoxy) silyl group have an alkoxy group in addition to the hydroxy group, and therefore they are also classified as an alkoxy silyl group.

  When the cyclopentene ring-opened polymer having a branched structure has such a modifying group, the introduction position of the modifying group is not particularly limited, but from the viewpoint of further enhancing the introduction effect, the terminal of the polymer chain It is preferable to have a modifying group. When the polymer chain has a modifying group at the end, a terminal-modified cyclopentene ring-opened polymer having a branched structure having a modifying group at the end of the polymer chain and a modifying group introduced at the polymer chain end A non-modified, unmodified cyclopentene ring-opened polymer having a branched structure may be mixed.

When the cyclopentene ring-opening polymer having a branched structure has a modifying group at the end of the polymer chain, the introduction ratio of the modifying group at the polymer chain end of the cyclopentene ring-opening polymer having a branched structure is not particularly limited. It is preferable that the value of the percentage of cyclopentene ring-opened polymer chain end number / cyclopentene ring-opened polymer chain number having branched structure having a branched structure into which a modifying group is introduced is 60% or more, more preferably It is 80% or more, more preferably 90% or more. The method for measuring the introduction ratio of the modifying group to the polymer chain terminal is not particularly limited. For example, the peak area ratio corresponding to the modifying group determined by ¹ H-NMR spectrum measurement and gel permeation chromatography And the number average molecular weight obtained from

  The synthesis method of the cyclopentene ring-opened polymer having a branched structure is not particularly limited as long as the target polymer can be obtained, and may be synthesized according to a conventional method, for example, synthesized according to the method described below Can.

That is, the cyclopentene ring-opened polymer having a branched structure can be produced, for example, in the presence of a polymerization catalyst containing a Group 6 transition metal compound (A) of the periodic table and an organoaluminum compound (B) represented by the following formula (11) It can be obtained by ring-opening polymerization of a monomer mixture containing cyclopentene and a monomer capable of forming a branched structure.
(R ³ ) _3-x Al (OR ⁴ ) _x (11)
(In the formula (11), ^{R 3} and ^{R 4} represents a hydrocarbon group having 1 to 20 carbon atoms, x is a 0 <x <3.)

  The amount of each monomer used in the monomer mixture containing the cyclopentene and the monomer capable of forming a branched structure, which is used for the polymerization, may be an amount according to the above-mentioned content ratio.

  The periodic table group 6 transition metal compound (A) is a compound having a periodic table (long period periodic table, the same applies hereinafter) group 6 transition metal atom, specifically a chromium atom, a molybdenum atom, or a tungsten atom. Compounds having a molybdenum atom or a compound having a tungsten atom are preferable, and in particular, a compound having a tungsten atom is more preferable from the viewpoint of high solubility in cyclopentene or a monomer capable of forming a branched structure. . The periodic table group 6 transition metal compound (A) may be a compound having a periodic table group 6 transition metal atom, and is not particularly limited, but halides and alcoholates of the periodic table group 6 transition metal atom And arylates and oxides, and among these, halides are preferred from the viewpoint of high polymerization activity.

  As a specific example of such periodic table group 6 transition metal compound (A), molybdenum compounds such as molybdenum pentachloride, molybdenum oxo tetrachloride, molybdenum (phenyl imide) tetrachloride; tungsten hexachloride, tungsten oxo tetrachloride, Tungsten compounds such as tungsten (phenyl imide) tetrachloride, monocatecholate tungsten tetrachloride, bis (3,5-ditertiary butyl) catecholate tungsten dichloride, bis (2-chloroetherate) tetrachloride, tungsten oxo tetraphenolate and the like And the like.

  The amount of the periodic table group 6 transition metal compound (A) used is usually 1: 100 to 1: 200, in terms of the molar ratio of "the group 6 transition metal atom in the polymerization catalyst: the monomer mixture used for the polymerization". Preferably in the range of 1: 200 to 1: 150,000, more preferably in the range of 1: 500 to 1: 100,000. If the amount of the periodic table group 6 transition metal compound (A) used is too small, the polymerization reaction may not proceed sufficiently. On the other hand, if the amount is too large, removal of the catalyst residue from the cyclopentene ring-opened polymer having a branched structure may be difficult, and various properties of the resulting crosslinked rubber may be degraded.

The organoaluminum compound (B) is a compound represented by the above formula (11). Specific examples of the hydrocarbon group having 1 to 20 carbon atoms represented by ^{R 3} and ^{R 4} in formula (11), a methyl group, an ethyl group, an isopropyl group, n- propyl group, an isobutyl group, n- butyl group An alkyl group such as t-butyl group, n-hexyl group or cyclohexyl group; an aryl group such as phenyl group, 4-methylphenyl group, 2,6-dimethylphenyl group, 2,6-diisopropylphenyl group or naphthyl group; Etc. In the compound represented by the formula (11), the groups represented by R ³ and R ⁴ may be the same or different, but in the cyclopentene ring-opened polymer having a branched structure obtained Among R ³ and R ⁴ , at least R ⁴ of R ³ and R ⁴ is preferably an alkyl group formed by continuously bonding 4 or more carbon atoms from the viewpoint that the cis ratio can be controlled in the above-mentioned preferred range. And n-butyl, 2-methyl-pentyl, n-hexyl, cyclohexyl, n-octyl or n-decyl are more preferred.

Moreover, in the said Formula (11), x is 0 <x <3. That is, in the formula (11), the composition ratio of R ³ and OR ⁴ can take any value in each range of 0 <3-x <3 and 0 <x <3, respectively. From the viewpoint that the polymerization activity can be increased and the cis ratio of the cyclopentene ring-opened polymer having a branched structure obtained can be controlled to the above-mentioned preferred range, x is 0.5 <x <1.5. Is preferred.

The organoaluminum compound (B) represented by the above formula (11) can be synthesized, for example, by the reaction of trialkylaluminum with an alcohol as shown in the following formula (12).
(R ³ ) ₃ Al + _x R ⁴ OH → (R ³ ) _3-x Al (OR ⁴ ) _x + (R ³ ) _x H (12)

  Incidentally, x in the above formula (11) can be arbitrarily controlled by defining the reaction ratio of the corresponding trialkylaluminum and alcohol as shown in the above formula (12).

  The amount of the organoaluminum compound (B) used varies depending on the type of the organoaluminum compound (B) to be used, but relative to the Group 6 transition metal atom of the periodic table Group 6 transition metal compound (A) Preferably, it is a ratio of 0.1 to 100 times mol, more preferably 0.2 to 50 times mol, still more preferably 0.5 to 20 times mol. If the amount of the organoaluminum compound (B) used is too small, the polymerization activity may be insufficient. If it is too large, side reactions tend to occur easily during ring-opening polymerization.

  The ring-opening polymerization reaction may be carried out without a solvent or in solution. As a solvent used when conducting ring-opening polymerization reaction in solution, cyclopentene which is inactive in the polymerization reaction and is used for ring-opening polymerization, a monomer capable of forming a branched structure, and the above-mentioned polymerization catalyst can be dissolved No particular limitation is imposed on the solvent, and examples thereof include hydrocarbon solvents and halogen solvents. Specific examples of hydrocarbon solvents include, for example, aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene; aliphatic hydrocarbons such as n-hexane, n-heptane and n-octane; cyclohexane, cyclopentane, methyl Alicyclic hydrocarbons such as cyclohexane; and the like. Further, specific examples of the halogen-based solvent include alkyl halogens such as dichloromethane and chloroform; and aromatic halogens such as chlorobenzene and dichlorobenzene.

  In addition, a modifying group-containing olefinically unsaturated compound which is a compound having the above-described modifying group and having one metathesis reactive olefinic carbon-carbon double bond in a polymerization reaction system of ring-opening polymerization reaction When a hydrocarbon (C) is present, a modifying group can be introduced at the polymer chain end of the cyclopentene ring-opened polymer having a branched structure. For example, in the case of introducing an oxysilyl group at the polymer chain end of a cyclopentene ring-opened polymer having a branched structure, an oxysilyl group-containing olefinically unsaturated hydrocarbon may be present in the polymerization reaction system.

  As an example of such an oxysilyl group-containing olefinic unsaturated hydrocarbon, vinyl (trimethoxy) silane, vinyl (a vinyl (trimethoxy) silane, and the like) can be introduced into the polymer chain of a cyclopentene ring-opened polymer having a branched structure. Triethoxy) silane, allyl (trimethoxy) silane, allyl (methoxy) (dimethyl) silane, allyl (triethoxy) silane, allyl (ethoxy) (dimethyl) silane, styryl (trimethoxy) silane, styryl (triethoxy) silane, 2-styrylethyl Alkoxysilane compounds such as (triethoxy) silane, allyl (triethoxysilylmethyl) ether, allyl (triethoxysilylmethyl) (ethyl) amine; vinyl (triphenoxy) silane, allyl (triphenoxy) silane, allyl (pheno) Aryloxysilane compounds such as (dimethyl) silane; vinyl (triacetoxy) silane, allyl (triacetoxy) silane, allyl (diacetoxy) methylsilane, acyloxysilane compounds such as allyl (acetoxy) (dimethyl) silane; allyltris ( Alkylsiloxysilane compounds such as trimethylsiloxy) silanes; arylsiloxysilane compounds such as allyltris (triphenylsiloxy) silanes; 1-allylheptamethyltrisiloxane, 1-allynylnonamethyltetrasiloxane, 1-allynylnonamethylcyclopentasiloxane, Polysiloxane compounds such as 1-allylundecamethylcyclohexasiloxane; and the like. In addition, 1,4-bis (trimethoxysilyl) -2-butene and 1,4-bis (triethoxy) are introduced as those in which two oxysilyl groups are introduced into the polymer chain of a cyclopentene ring-opened polymer having a branched structure. Alkoxysilane compounds such as silyl) -2-butene and 1,4-bis (trimethoxysilylmethoxy) -2-butene; aryloxysilane compounds such as 1,4-bis (triphenoxysilyl) -2-butene; 1 Acyloxysilane compounds such as 2,4-bis (triacetoxysilyl) -2-butene; alkylsiloxysilane compounds such as 1,4-bis [tris (trimethylsiloxy) silyl] -2-butene; Arylsiloxysilane compounds such as tris (triphenylsiloxy) silyl] -2-butene; 1,4-bis (heptamethyltri) Proxy) -2-butene, 1,4-bis (polysiloxane compounds such undecapeptide methylcyclohexanol siloxy) -2-butene; and the like.

  The use amount of the modified group-containing olefinically unsaturated hydrocarbon (C) such as the oxysilyl group-containing olefinically unsaturated hydrocarbon may be appropriately selected according to the molecular weight of the cyclopentene ring-opened polymer having a branched structure to be produced. And the monomer mixture containing cyclopentene used for the polymerization and the monomer capable of forming a branched structure, the molar ratio is usually 1/100 to 1 / 100,000, preferably 1/200 to 1/50, More preferably, it is in the range of 1/500 to 1 / 10,000. The modified group-containing olefinically unsaturated hydrocarbon (C) acts as a molecular weight modifier in addition to the action of introducing a modifying group to the polymer chain terminal of the cyclopentene ring-opened polymer having a branched structure.

  Alternatively, when the above-described modifying group is not introduced into the cyclopentene ring-opening polymer having a branched structure, 1- as a molecular weight modifier in order to adjust the molecular weight of the obtained cyclopentene ring-opening polymer having a branched structure. Olefin compounds such as butene, 1-pentene, 1-hexene, 1-octene and the like, 1,4-pentadiene, 1,4-hexadiene, 1,5-hexadiene, 1,6-heptadiene, 2-methyl-1,4- Diolefin compounds such as pentadiene and 2,5-dimethyl-1,5-hexadiene may be added to the polymerization reaction system. The amount of use of the molecular weight modifier may be appropriately selected from the same range as that of the above-mentioned olefin-unsaturated hydrocarbon-containing hydrocarbon (C).

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

  Alternatively, a ruthenium carbene complex is used as a polymerization catalyst instead of the method using a polymerization catalyst containing the periodic table group 6 transition metal compound (A) and the organoaluminum compound (B) represented by the formula (11) Thus, a cyclopentene ring-opened polymer having a branched structure can also be produced by ring-opening polymerization of a monomer mixture containing cyclopentene and a monomer capable of forming a branched structure in the presence of a ruthenium carbene complex. .

  The ruthenium carbene complex is not particularly limited as long as it is a catalyst for ring opening polymerization of cyclopentene. Specific examples of the ruthenium carbene complex preferably used include bis (tricyclohexylphosphine) benzylideneruthenium dichloride, bis (triphenylphosphine) -3,3-diphenylpropenylideneruthenium dichloride, (3-phenyl-1H-indene-1 -Ylidene) bis (tricyclohexylphosphine) ruthenium dichloride, bis (tricyclohexylphosphine) t-butylvinylidene ruthenium dichloride, bis (1,3-diisopropylimidazolin-2-ylidene) benzylidene ruthenium dichloride, bis (1,3-dicyclohexylimidazoline) -2-ylidene) benzylidene ruthenium dichloride, (1,3-dimesitylimidazolin-2-ylidene) (tricyclohexylphosphine) benzyl Ruthenium dichloride, (1,3-dimesitylimidazolidin-2-ylidene) (tricyclohexylphosphine) benzylideneruthenium dichloride, bis (tricyclohexylphosphine) ethoxymethylideneruthenium dichloride, (1,3-dimesitylimidazolidine -2-ylidene) (tricyclohexylphosphine) ethoxymethylidene ruthenium dichloride and the like can be mentioned.

  The amount of the ruthenium carbene complex used is usually 1: 2,000 to 1: 2,000,000, preferably 1: 5,000 to (molar metal ruthenium in the catalyst: monomer used for polymerization) molar ratio The range is 1: 1,500,000, more preferably 1: 10,000 to 1: 1,000,000. If the amount of the ruthenium carbene complex used is too small, the polymerization reaction may not proceed sufficiently. On the other hand, if the amount is too large, removal of the catalyst residue from the obtained cyclopentene ring-opened polymer having a branched structure is difficult, and various properties may be reduced when it is made into a rubber cross-linked product.

  When using a ruthenium carbene complex as a polymerization catalyst, the ring-opening polymerization reaction may be performed without a solvent or may be performed in a solution. As a solvent used when performing ring-opening polymerization reaction in solution, a polymerization catalyst containing the periodic table group 6 transition metal compound (A) described above and the organic aluminum compound (B) represented by the formula (11) is used The same ones as in the case can be used.

  The polymerization reaction temperature and the polymerization reaction time are also the same as in the case of using the polymerization catalyst containing the group 6 transition metal compound (A) of the periodic table described above and the organoaluminum compound (B) represented by the formula (11).

  Then, a method using a polymerization catalyst containing the above-mentioned periodic table group 6 transition metal compound (A) and the organoaluminum compound (B) represented by the formula (11), or a method using a ruthenium carbene complex as the polymerization catalyst If desired, an antioxidant such as a phenol-based stabilizer, a phosphorus-based stabilizer, or a sulfur-based stabilizer may be added to the cyclopentene ring-opening polymer having a branched structure obtained by The addition amount of the antiaging agent may be appropriately determined according to the type and the like. Furthermore, if desired, an extender oil may be blended. When a cyclopentene ring-opened polymer having a branched structure is obtained as a polymer solution, in order to recover the polymer from the polymer solution, a known recovery method may be adopted. For example, a solvent is removed by steam stripping or the like. After separation, the solid may be separated by filtration and then dried to obtain a solid rubber.

  The rubber component used in the present invention may contain other rubber in addition to the cyclopentene ring-opened polymer having a branched structure. Examples of the rubber other than the cyclopentene ring-opening polymer having a branched structure include natural rubber (NR), polyisoprene rubber (IR), solution-polymerized SBR (solution-polymerized styrene butadiene rubber), emulsion-polymerized SBR (emulsion-polymerized styrene butadiene rubber) ), Low cis BR (polybutadiene rubber), high cis BR, high trans BR (trans bond content of butadiene portion 70 to 95%), styrene-isoprene copolymer rubber, butadiene-isoprene copolymer rubber, ethylene propylene diene rubber ( EPDM), emulsion-polymerized styrene-acrylonitrile-butadiene copolymer rubber, acrylonitrile-butadiene copolymer rubber, polyisoprene-SBR block copolymer rubber, polystyrene-polybutadiene-polystyrene block copolymer, acrylic rubber, epichlorohydrin Arm, fluorine rubber, silicone rubber, ethylene - propylene rubber, and urethane rubber. Among them, NR, BR, IR, solution-polymerized SBR, emulsion-polymerized SBR, and EPDM are preferably used. These rubbers can be used alone or in combination of two or more.

  In the rubber component used in the present invention, the content of the cyclopentene ring-opened polymer having a branched structure is preferably 10% by weight or more based on all the rubber components from the viewpoint of making the effect of the present invention more remarkable. More preferably, it is 50 weight% or more, More preferably, it is 70 weight% or more. On the other hand, the content of rubber other than the cyclopentene ring-opened polymer having a branched structure is preferably 90% by weight or less, more preferably 50% by weight or less, more preferably 30% by weight, based on all rubber components. % Or less.

  The polymer composition used in the present invention is obtained by blending carbon black with the rubber component containing the cyclopentene ring-opened polymer having the branched structure described above.

  As carbon black, furnace black, acetylene black, thermal black, channel black, graphite and the like can be mentioned. Among these, it is preferable to use furnace black, and specific examples thereof include SAF, ISAF, ISAF-HS, ISAF-LS, IISAF-HS, HAF, HAF-HS, HAF-LS, MAF, FEF, etc. It can be mentioned. These can be used alone or in combination of two or more.

The carbon black has a nitrogen adsorption specific surface area (N ₂ SA) of preferably 5 to 200 m ² / g, more preferably 20 to 150 m ² / g, and the dibutyl phthalate (DBP) adsorption amount is preferably 5 to 200 ml / 100 g, more preferably 50 to 160 ml / 100 g. The nitrogen adsorption specific surface area can be measured by the BET method in accordance with ASTM D-4820.

  The content of carbon black in the polymer composition used in the present invention is 20 to 200 parts by weight, preferably 25 to 50 parts by weight, with respect to 100 parts by weight of the rubber component containing a cyclopentene ring-opened polymer having a branched structure. It is 150 parts by weight, more preferably 35 to 100 parts by weight. According to the present invention, as the cyclopentene ring-opening polymer, one having a branched structure is used, and by setting the content of carbon black in the above range, the compression set resistance when made into a rubber cross-linked product is obtained. The resulting rubber cross-linked product can be made excellent in compression set resistance for use. When the content of carbon black is too low, the obtained rubber cross-linked product is inferior in mechanical properties. On the other hand, when the content of carbon black is too large, the processability as a polymer composition becomes inferior.

  The rubber cross-linked product of the present invention is obtained by cross-linking a polymer composition obtained by blending carbon black with a rubber component containing a cyclopentene ring-opened polymer having such a branched structure. The compression set has a specific range when compressed under the following conditions. That is, the crosslinked rubber product of the present invention has a compression set of 35% or less, preferably 30% or less, and more preferably 28 after being maintained at 100 ° C. for 72 hours in a 25% compressed state. % Or less. Although the lower limit of the compression set rate is not particularly limited, it is usually 10% or more. The compression set can be measured in accordance with JIS K6262: 2013 after holding at 100 ° C. for 72 hours in a state where the crosslinked rubber product is compressed by 25%.

  In the present invention, the method for setting the compression set rate S to the above range is not particularly limited, but the content ratio of the branched structural unit contained in the cyclopentene ring-opened polymer having a branched structure in the polymer composition is adjusted It can adjust by the method etc. and the method etc. which adjust content of carbon black with respect to the rubber component containing the cyclopentene ring-opened polymer which has a branched structure in the range mentioned above.

  Further, the polymer composition used in the present invention includes, in addition to the above components, a crosslinking agent, a crosslinking accelerator, a crosslinking activator, an antiaging agent, an activator, a processing oil, a plasticizer, a wax, a carbon according to a conventional method. Necessary amounts of additives such as fillers other than black can be blended respectively.

  Examples of the crosslinking agent include sulfur, sulfur halides, organic peroxides, quinone dioximes, organic polyhydric amine compounds, zinc acrylates and alkylphenol resins having a methylol group. Among these, sulfur and organic peroxides are preferably used. The compounding amount of the crosslinking agent is preferably 0.5 to 5 parts by weight, more preferably 0.7 to 4 parts by weight, still more preferably 1 to 3 parts by weight with respect to 100 parts by weight of the rubber component in the polymer composition. It is a department.

  As a crosslinking accelerator, for example, N-cyclohexyl-2-benzothiazolylsulfenamide, N-t-butyl-2-benzothiazolylsulfenamide, N-oxyethylene-2-benzothiazolylsulfenamide, Sulfenamide-based crosslinking accelerators such as N-oxyethylene-2-benzothiazolylsulfenamide, N, N'-diisopropyl-2-benzothiazolylsulfenamide; 1,3-diphenylguanidine, 1,3- Guanidine-based crosslinking accelerators such as diorto-tolyl guanidine and 1-ortho-tolylbiguanidine; thiourea-based crosslinking accelerators; thiazole-based crosslinking accelerators; thiuram-based crosslinking accelerators; dithiocarbamic acid-based crosslinking accelerators; And the like. Among these, those containing a sulfenamide crosslinking accelerator are particularly preferable. These crosslinking accelerators may 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 with respect to 100 parts by weight of the rubber component in the polymer composition.

  Examples of the crosslinking activator include higher fatty acids such as stearic acid and zinc oxide. The blending amount of the crosslinking activator is not particularly limited, but the blending amount in the case of using a higher fatty acid as the crosslinking activator is preferably 0.05 to 100 parts by weight of the rubber component in the polymer composition. The amount is 15 parts by weight, more preferably 0.5 to 5 parts by weight, and the blending amount in the case of using zinc oxide as the crosslinking activator is preferably 0 with respect to 100 parts by weight of the rubber component in the polymer composition. It is from 0.5 to 15 parts by weight, more preferably from 0.5 to 5 parts by weight.

  Mineral oil and synthetic oil may be used as the process oil. As mineral oil, aromatic oil, naphthenic oil, paraffin oil and the like are usually used.

  As fillers other than carbon black, for example, metal powders such as aluminum powder; inorganic powders such as hard clay, talc, calcium carbonate, titanium oxide, calcium sulfate, calcium carbonate and aluminum hydroxide; organic substances such as starch and polystyrene powder Powders such as powders; glass fibers (milled fibers), carbon fibers, aramid fibers, short fibers such as potassium titanate whiskers; silica, mica, and the like. These fillers may be used alone or in combination of two or more.

  The method for obtaining the polymer composition used in the present invention is not particularly limited, and each component may be kneaded according to a conventional method, for example, a crosslinker and a crosslinker except for a compounding agent such as carbon black After kneading and a rubber component such as a cycloolefin ring-opened polymer having a branched structure, a crosslinker and a crosslinking accelerator can be mixed with the kneaded product to obtain a target composition. The kneading temperature of the compounding agent excluding the crosslinking agent and the crosslinking accelerator and the rubber component is preferably 70 to 200 ° C., more preferably 100 to 180 ° C. The kneading time is preferably 30 seconds to 30 minutes. The mixing of the kneaded product with the crosslinking agent and the crosslinking accelerator is usually performed after cooling to 100 ° C. or less, preferably 80 ° C. or less.

  The rubber cross-linked product according to the present invention can be obtained by cross-linking the above-mentioned polymer composition. The crosslinking method is not particularly limited, and may be selected according to the shape, size, etc. of the rubber crosslinked product. In the mold, the polymer composition may be filled and heated at the same time as the molding by crosslinking, or the previously molded polymer composition may be heated and crosslinked. The crosslinking temperature is preferably 120 to 200 ° C., more preferably 140 to 180 ° C., and the crosslinking time is usually about 1 to 120 minutes.

  Further, depending on the shape, size, etc. of the rubber cross-linked product, even if the surface is cross-linked, the cross-linking may not be sufficiently cross-linked to the inside.

  As a heating method, a general method used for crosslinking of rubber such as press heating, steam heating, oven heating, hot air heating may be appropriately selected.

  And, since the rubber cross-linked product according to the present invention obtained in this manner is excellent in compression set resistance, it can be suitably used for applications where compression set resistance is required. Specifically, O-rings, packings, diaphragms, oil seals, shaft seals, bearing seals, well head seals, shock absorber seals, seals for pneumatic equipment, cooling devices for air conditioners and compressors for refrigerator air conditioners Seals used for sealing fluorocarbons or fluorohydrocarbons or carbon dioxide, seals for sealing supercritical carbon dioxide or subcritical carbon dioxide used as cleaning media for precision cleaning, rolling devices (rolling bearings (hub bearings, hub units for automobiles) , Seal for automobile water pump, linear guide device and ball screw etc), valve and valve seat, BOP (Blow Out Preventar), various seal materials such as bladder; mounted on the connecting part of intake manifold and cylinder head Intekuma Ni-hold gaskets, cylinder head gaskets attached to the connection between the cylinder block and the cylinder head, rocker cover gaskets attached to the connection between the rocker cover and the cylinder head, the connection between the oil pan and the cylinder block or transmission case Various gaskets such as gaskets for fuel cell separators installed between a pair of housings sandwiching a unit cell provided with an oil pan gasket, a positive electrode, an electrolyte plate and a negative electrode It can be suitably used for applications.

  Hereinafter, the present invention will be described based on further detailed examples, but the present invention is not limited to these examples. In the following, "parts" are by weight unless otherwise specified. In addition, various tests and evaluations were performed according to the following methods.

[Cyclopentene ring-opened (co) polymer, molecular weight of butadiene rubber]
The weight average molecular weight (Mw) and molecular weight distribution (Mw / Mn) of cyclopentene ring-opened (co) polymer, butadiene rubber are obtained by gel permeation chromatography (GPC) to obtain a chart based on the molecular weight in terms of polystyrene, Determined based on the chart. The specific measurement conditions for gel permeation chromatography are as follows.
Measuring instrument: HLC-8320 EcoSCE (made by Tosoh Corporation)
Column: Two GMH-HR-H (made by Tosoh Corporation) were connected in series.
Detector: Differential refractometer RI-8020 (made by Tosoh Corporation)
Eluent: tetrahydrofuran Column temperature: 40 ° C

[Proportion of structural unit derived from monomer capable of forming branched structure in cyclopentene ring-opened copolymer]
^{It was} determined by measuring the monomer composition ratio in the cyclopentene ring-opened copolymer by ¹ H-NMR spectrum measurement.

[Cis / trans ratio of cyclopentene ring-opened (co) polymer, vinyl / cis / trans ratio of butadiene rubber]
^It was determined from ¹³ C-NMR spectrum measurement.

[Introduction rate of oxysilyl group of cyclopentene ring-opened (co) polymer]
^The ratio of the peak integral value derived from the oxysilyl group to the peak integral value derived from the carbon-carbon double bond in the terminal-modified cyclopentene ring-opened (co) polymer main chain is determined by ¹ H-NMR spectrum measurement. Based on the ratio of the peak integral value and the measured value of the number average molecular weight (Mn) by GPC, the introduction rate of the oxysilyl group [(Cyclopentene ring-opened (co) polymer chain terminal number / terminal-modified cyclopentene opening with introduced oxysilyl group Percentage of ring (co) polymer chain number) was calculated.

[Glass transition temperature (Tg)]
The glass transition temperature (Tg) was measured at a temperature rise of 10 ° C./min using a differential scanning calorimeter (DSC, X-DSC 7000 manufactured by Hitachi High-Tech Science Co., Ltd.).

[Compression permanent distortion rate]
The polymer composition to be a sample was press-molded at 150 ° C. for 30 minutes using a mold, under pressure, to obtain a cylindrical rubber crosslinked product having a diameter of 29 mm and a thickness of 12.5 mm. Then, using the obtained columnar rubber cross-linked product, in a state where the distance between the two planes sandwiching the columnar rubber cross-linked product is compressed by 25% in the disc thickness direction, the gear aging tester (product name “ The compression set was measured according to JIS K6262: 2013 under the conditions of holding at 100 ° C. for 72 hours using “AG-1110”, manufactured by Ueshima Seisakusho Co., Ltd.).

[Reference Example 1]
Preparation of diisobutylaluminum monomethoxide / toluene solution (2.5% by weight) In a glass container containing a stirrer under a nitrogen atmosphere, 61 parts of toluene and 25.4% by weight of triisobutylaluminum / n-hexane solution ( 7.8 parts of Tosoh Fine Chem Co., Ltd. were added. The vessel was then cooled to -45 ° C and 0.32 parts of methanol (equimolar to triisobutylaluminum) was slowly added dropwise with vigorous stirring. Then, it was allowed to reach room temperature with stirring to prepare a diisobutylaluminum monomethoxide / toluene solution (2.5% by weight).

Reference Example 2
Preparation of diisobutylaluminum mono (n-hexoxide) / toluene solution (2.5% by weight) In a glass container with a stirrer under a nitrogen atmosphere, 88 parts of toluene and 25.4% by weight of triisobutylaluminum / n -7.8 parts of hexane solution (made by Tosoh Fine Chem Co., Ltd.) was added. The vessel was then cooled to -45 ° C and 1.02 parts (equimolar to triisobutylaluminum) of n-hexanol was slowly added dropwise with vigorous stirring. Then, it was allowed to reach room temperature with stirring to prepare a diisobutylaluminum mono (n-hexoxide) / toluene solution (2.5% by weight).

Synthesis Example 1
In a nitrogen atmosphere, 3000 parts of cyclopentene, 16.2 parts of norbornadiene (NBD), 9.32 parts of 1,2-bis (triethoxysilyl) ethylene, and 2.5 prepared in Reference Example 1 in a pressure-resistant glass reaction vessel equipped with a stirrer 5 parts by weight of diisobutylaluminum monomethoxide / toluene solution were added and heated to 50.degree. Here, 14.5 parts of a 1.0 wt% WCl ₆ / toluene solution was added, and a polymerization reaction was performed at 50 ° C. for 4 hours. After polymerization reaction for 4 hours, excess ethyl alcohol is added to the pressure resistant glass reaction vessel to terminate the polymerization, and then the solution in the pressure resistant glass reaction vessel is reacted with 2,6-di-t-butyl-p-cresol (BHT). Pour into a large excess of ethyl alcohol including Then, the precipitated polymer is recovered, washed with ethyl alcohol, and vacuum-dried at 40 ° C. for 3 days to introduce a triethoxysilyl group at the polymer chain end, terminal-modified cyclopentene / norbornadiene ring-opening coweight Obtained 466 parts of union. This terminally modified cyclopentene / norbornadiene ring-opening copolymer is derived from the allylic proton in the norbornadiene structural unit in which only the olefin moiety of one ring is ring-opened by ¹ H-NMR spectrum measurement and various two-dimensional NMR spectrum measurements. A peak was observed around 3.50 to 3.62 ppm. In addition, a peak derived from the allylic proton in the norbornadiene structural unit in which the olefin moieties of the two rings are all ring-opened to form a branched structure was observed at around 3.19 to 3.30 ppm. From these observation results, it was confirmed that the polymer is a branched polymer having a branched structure derived from norbornadiene in the cyclopentene ring-opened polymer main chain. In addition, the structural unit (a 4-branch structural unit) containing 54% of structural units (four branched structural units) in which all the olefin moieties of the two rings are open in the structure derived from all norbornadiene is a structural unit in which only one olefin site is opened. It was also confirmed that the content ratio of (non-branched structural unit) was 46%. And each measurement was performed according to the said method about the terminal-modified cyclopentene / norbornadiene ring-opening copolymer obtained. The results are shown in Table 1.

Synthesis Example 2
A terminal-modified cyclopentene / norbornadiene ring-opened copolymer in which a polymerization reaction was carried out in the same manner as in Synthesis Example 1 except that the amount of norbornadiene used was changed to 30.4 parts, and a triethoxysilyl group was introduced at the polymer chain terminal. I got 550 parts. And about each obtained terminal-modified cyclopentene / norbornadiene ring-opening copolymer, it carried out similarly to the synthesis example 1, and performed each measurement. The results are shown in Table 1.

Synthesis Example 3
In a nitrogen atmosphere, 3000 parts of cyclopentene, 16.2 parts of norbornadiene (NBD), 2.8 parts of 1-hexene, and 2.5% by weight of diisobutylaluminum monomethoxide prepared in Reference Example 1 in a pressure resistant glass reactor equipped with a stirrer 1 part of toluene solution was added and heated to 50.degree. To this was added 2.9 parts of a 1.0 wt% WCl ₆ / toluene solution, and a polymerization reaction was carried out at 50 ° C. for 4 hours. After polymerization reaction for 4 hours, excess ethyl alcohol is added to the pressure resistant glass reaction vessel to terminate the polymerization, and then the solution in the pressure resistant glass reaction vessel is reacted with 2,6-di-t-butyl-p-cresol (BHT). Pour into a large excess of ethyl alcohol including Then, the precipitated polymer was recovered, washed with ethyl alcohol and vacuum dried at 40 ° C. for 3 days to obtain 723 parts of a non-modified cyclopentene / norbornadiene ring-opened copolymer. Each measurement was performed on the obtained unmodified cyclopentene / norbornadiene ring-opened copolymer in the same manner as in Synthesis Example 1. The results are shown in Table 1.

The cyclopentene / norbornadiene ring-opened copolymers obtained in Synthesis Examples 2 and 3 were also measured by ¹ H-NMR spectrum measurement and various two-dimensional NMR spectrum measurement in the same manner as in Synthesis Example 1. The cyclopentene ring-opened polymer was confirmed to be a branched polymer having a branched structure derived from norbornadiene in the main chain. Also in the cyclopentene / norbornadiene ring-opened copolymers obtained in Synthesis Examples 2 and 3, the proportion of structural units (4-branch structural units) in which all the olefin moieties of the two rings are ring-opened in all norbornadiene-derived structures In the range of 50 to 60%, the proportion of structural units (non-branched structural units) in which only the olefin moiety of one ring was opened was in the range of 40 to 50%.

Synthesis Example 4
A polymerization reaction is carried out in the same manner as in Synthesis Example 1 except that 2.94 parts of 5-vinyl-2-norbornene is used in place of norbornadiene, and a triethoxysilyl group is introduced at the polymer chain terminal. 792 parts of 5-vinyl-2-norbornene ring-opening copolymer were obtained. Each measurement was performed on the obtained terminal-modified cyclopentene / 5-vinyl-2-norbornene ring-opened copolymer in the same manner as in Synthesis Example 1. The results are shown in Table 1.

The terminally modified cyclopentene / norbornadiene ring-opened copolymer obtained in Synthesis Example 4 was subjected to ¹ H-NMR spectrum measurement to find that 5-vinyl-2-norbornene derived from the cyclopentene ring-opened polymer main chain It confirmed that it was a branched polymer which has a branched structure.

Synthesis Example 5
Under nitrogen atmosphere, 87 parts of a 1.0 wt% WCl ₆ / toluene solution and 2.5 wt% of diisobutylaluminum mono (n-hexoxide) / toluene prepared in Reference Example 2 in a glass container containing a stirrer A catalyst solution was obtained by adding 43 parts of the solution and stirring for 15 minutes. Then, under a nitrogen atmosphere, 300 parts of cyclopentene and 1.24 parts of 1,4-bis (triethoxysilyl) -2-butene were added to a pressure resistant glass reaction vessel equipped with a stirrer, and the catalyst solution 130 prepared above was added thereto. Part was added and polymerization reaction was performed at 25 ° C. for 4 hours. After 4 hours of polymerization reaction, excess ethyl alcohol was added to a pressure resistant glass reaction vessel to stop the polymerization, and then Irganox 1520 L (manufactured by Ciba Specialty Chemicals) was used as an anti-aging agent. 0.2 part was added with respect to 100 parts of union. Next, the polymer is recovered by coagulation with a large amount of ethanol, and the polymer is recovered by vacuum drying at 40 ° C. for 3 days, whereby 78 parts of a terminal-modified cyclopentene ring-opened polymer in which a triethoxysilyl group is introduced at the polymer chain terminal I got Each measurement was performed on the obtained terminal-modified cyclopentene ring-opened polymer in the same manner as in Synthesis Example 1. The results are shown in Table 1.

Synthesis Example 6
After charging 5670 g of cyclohexane and 700 g of 1,3-butadiene under a nitrogen atmosphere in a stirrer-equipped autoclave, it is necessary to neutralize the impurities contained in n-butyllithium and contained in cyclohexane and 1,3-butadiene. An amount was added, and 8.33 mmol was added to use n-butyllithium for the polymerization reaction, and the polymerization was initiated at 50 ° C. Twenty minutes after initiation of the polymerization, 300 g of 1,3-butadiene was continuously added over 30 minutes. The maximum temperature during the polymerization reaction was 80.degree.
After completion of the continuous addition, the polymerization reaction is continued for another 15 minutes, and after confirming that the polymerization conversion ratio is in the range of 95% to 100%, 1,6-bis (trichlorosilyl) hexane 0 .333 mmol (corresponding to 0.04 moles of n-butyllithium used for polymerization) was added in the form of a 40 wt% cyclohexane solution, and allowed to react for 30 minutes. Furthermore, thereafter, 2.92 mmol of polyorganosiloxane represented by the following formula (13) (corresponding to 0.35 moles of n-butyllithium used for polymerization) is added in the form of a 20 wt% xylene solution; The reaction was allowed to proceed for a minute, and then 8.33 mmol of tetramethoxysilane (corresponding to 1 mole of n-butyllithium used for polymerization) was added in the form of a 25 wt% cyclohexane solution, and allowed to react for 30 minutes. Thereafter, as a polymerization terminator, methanol was added in an amount corresponding to 2 moles of n-butyllithium used to obtain a solution containing terminal-modified polybutadiene. Then, 0.2 parts of Irganox 1520 L (manufactured by Ciba Specialty Chemicals Inc.) as an anti-aging agent is added to 100 parts of the rubber component and the solvent is removed by steam stripping at 60 ° C. By drying under vacuum for 24 hours, a terminal-modified butadiene rubber was obtained. The weight average molecular weight (Mw) of the terminally modified butadiene rubber obtained was 553,000, and the vinyl / cis / trans ratio was vinyl / cis / trans = 10/45/45.

Example 1
In a Banbury mixer, 100 parts of the terminally modified cyclopentene / norbornadiene ring-opened polymer obtained in Synthesis Example 1 are masticated for 30 seconds, and then 2 parts of stearic acid, 3 parts of zinc oxide, carbon black (trade name: IRB 60 parts of NO. 8 ", CONTINENTAL CARBON company, nitrogen adsorption specific surface area (BET method): 76.3 m ² / g, and process oil (JX Nippon Mining & Energy Co., Ltd., trade name" Aromax T-DAE " After 15 parts were added and the mixture was kneaded at 110 ° C. for 180 seconds, the compounding agent remaining on the upper part of the ram was cleaned, and the mixture was further kneaded for 150 seconds, and the mixture was discharged from the mixer. Next, the kneaded material is cooled to room temperature, and then the obtained kneaded material, sulfur, 1.5 parts, and N- (tert-butyl) -2-benzo as a crosslinking accelerator with an open roll at 23 ° C. A sheet-like polymer composition was obtained after kneading with 0.9 parts of thiazolylsulfenamide (manufactured by Ouchi Emerging Chemical Industry Co., Ltd., trade name "Noxceler NS-P").

  Then, using the obtained polymer composition, a rubber cross-linked product was obtained according to the above-mentioned method, and a compression set test was conducted. The results are shown in Table 1.

Example 2
Example 1 was repeated except that 100 parts of the terminally modified cyclopentene / norbornadiene ring-opened polymer obtained in Synthesis Example 2 were used instead of 100 parts of the terminal-modified cyclopentene / norbornadiene ring-opened polymer obtained in Synthesis Example 1 Similarly, a polymer composition was obtained and evaluated in the same manner. The results are shown in Table 1.

[Example 3]
Example 1 and Example 1 except that 100 parts of the unmodified cyclopentene / norbornadiene ring-opened polymer obtained in Synthesis Example 3 were used instead of 100 parts of the terminally modified cyclopentene / norbornadiene ring-opened polymer obtained in Synthesis Example 1 Similarly, a polymer composition was obtained and evaluated in the same manner. The results are shown in Table 1.

Example 4
Instead of 100 parts of the terminally modified cyclopentene / norbornadiene ring-opening polymer obtained in Synthesis Example 1, 100 parts of the terminal-modified cyclopentene / 5-vinyl-2-norbornene ring-opening copolymer obtained in Synthesis Example 4 was used A polymer composition was obtained and evaluated in the same manner as in Example 1 except for the above. The results are shown in Table 1.

Comparative Example 1
The procedure of Example 1 is repeated except that 100 parts of the terminally modified cyclopentene ring-opened polymer obtained in Synthesis Example 5 is used in place of 100 parts of the terminal-modified cyclopentene / norbornadiene ring-opened polymer obtained in Synthesis Example 1. The polymer composition was obtained and evaluated in the same manner. The results are shown in Table 1.

Comparative Example 2
In the same manner as in Example 1, except that 100 parts of the terminally modified butadiene rubber obtained in Synthesis Example 6 was used instead of 100 parts of the terminally modified cyclopentene / norbornadiene ring-opened polymer obtained in Synthesis Example 1 The combined composition was obtained and evaluated in the same manner. The results are shown in Table 1.

  As shown in Table 1, according to the results of Examples 1 to 4, a rubber crosslinked product according to the present invention, which is obtained by crosslinking a cyclopentene ring-opened polymer having a branched structure and a polymer composition containing a predetermined amount of carbon black. Is lower in compression set rate as compared with the case of using a cyclopentene ring-opened polymer having no branched structure or a butadiene rubber instead of the cyclopentene ring-opened polymer having a branched structure (Comparative Examples 1 and 2) It is excellent in compression set resistance, and from this result, it can be said that the rubber cross-linked product of the present invention can be suitably used in applications where compression set resistance is required.

Claims (5)

A rubber crosslinked product obtained by crosslinking a polymer composition containing 20 to 200 parts by weight of carbon black with respect to 100 parts by weight of a rubber component containing a cyclopentene ring-opening polymer having a branched structure,
A rubber cross-linked product having a compression set of 35% or less after holding at 100 ° C. for 72 hours in a state of 25% compression. The rubber cross-linked product according to claim 1, wherein the cyclopentene ring-opened polymer having a branched structure has a branched structure starting from a branched structural unit represented by the following formula (I).

(In the above formula (I), a hydrogen atom may be substituted with an alkyl group having 1 to 6 carbon atoms.) The rubber cross-linked product according to claim 1, wherein the cyclopentene ring-opening polymer having a branched structure has a branched structure starting from a branched structural unit represented by the following formula (II).

(In the above formula (II), a hydrogen atom may be substituted with an alkyl group having 1 to 6 carbon atoms.) The rubber cross-linked product according to claim 1, wherein the cyclopentene ring-opened polymer having a branched structure has a branched structure starting from a branched structural unit represented by the following formula (III).

(In the above formula (III), a hydrogen atom may be substituted with an alkyl group having 1 to 6 carbon atoms.) The rubber cross-linked product according to claim 1, wherein the cyclopentene ring-opening polymer having a branched structure has a branched structure starting from a branched structural unit represented by the following formula (IV).

(In the above formula (IV), a hydrogen atom may be substituted with an alkyl group having 1 to 6 carbon atoms.)