WO2021079844A1

WO2021079844A1 - Rubber composition, and rubber crosslinked product and pneumatic tire using said rubber composition

Info

Publication number: WO2021079844A1
Application number: PCT/JP2020/039238
Authority: WO
Inventors: 淳野澤
Original assignee: 日本ゼオン株式会社
Priority date: 2019-10-25
Filing date: 2020-10-19
Publication date: 2021-04-29
Also published as: JPWO2021079844A1

Abstract

Provided is a rubber composition with which a rubber crosslinked product having good workability and an excellent balance between rolling resistance and wet grip performance can be obtained. Provided is a rubber composition containing a diene rubber and a hydrocarbon resin, wherein the hydrocarbon resin content is 1-200 parts by mass per 100 parts by mass of the diene rubber, the hydrocarbon resin contains monomer units derived from a tetracyclododecene compound in a proportion of 0.1-50% by weight, the weight-average molecular weight (Mw) is in the range of 500-4,000, and the softening point is in the range of 80-170°C.

Description

Rubber composition and rubber cross-linked products and pneumatic tires using it

The present invention relates to a rubber composition, and more particularly to a rubber composition capable of obtaining a rubber crosslinked product having good workability and an excellent balance between rolling resistance and wet grip performance.

In recent years, automobile tires are strongly required to have low fuel consumption due to environmental problems and resource problems, while improvement of wet grip is required from the viewpoint of safety, for example. A crosslinked product of a rubber composition containing silica as a filler in a rubber component has a smaller rolling resistance when a tire is formed than a crosslinked product of a rubber composition containing carbon black. Therefore, by constructing a tire using a crosslinked product of a rubber composition containing silica, a tire having excellent fuel efficiency can be obtained.

However, even if silica is blended with the conventional rubber component, the affinity between the rubber component and silica is insufficient, and the rubber composition before cross-linking is poorly processable due to the fact that these are easily separated. Further, the rubber crosslinked product obtained by cross-linking these has a problem that the rolling resistance when the tire is constructed becomes insufficient.

Further, in Patent Document 1, for the purpose of improving the rolling resistance and wet grip property of the tire, a specific amount of a softener having a specific structure is blended in the rubber component, and a specific amount of a hydrocarbon resin having a specific structure is blended. It is disclosed to do.

Japanese Unexamined Patent Publication No. 2010-241965

The softener and hydrocarbon resin having a specific structure described in Patent Document 1 certainly improve both wet grip properties and rolling resistance when a tire is manufactured from an elastomer crosslinked product obtained by adding them. It is possible, but there is a problem that it is still insufficient.

The present invention has been made in view of the above problems, and provides a rubber composition capable of obtaining a rubber crosslinked product having good workability and an excellent balance between rolling resistance and wet grip performance. The purpose is.

As a result of studies to achieve the above object, the present inventors have realized excellent processability as long as it is a rubber composition obtained by blending a specific hydrocarbon resin with a diene rubber. , It has been found that a rubber crosslinked product having an excellent balance between rolling resistance and wet grip performance can be obtained, and the present invention has been completed.

That is, according to the present invention, the rubber composition contains a diene-based rubber and a hydrocarbon resin, and the content of the hydrocarbon resin is 1 to 200 parts by mass with respect to 100 parts by mass of the diene-based rubber. The hydrocarbon resin contains a monomer unit derived from a tetracyclododecene compound in a proportion of 0.1 to 50% by weight, and has a weight average molecular weight (Mw) in the range of 500 to 4,000. , A rubber composition having a softening point in the range of 80 to 170 ° C. is provided.

In the rubber composition of the present invention, the hydrocarbon resin has a 1,3-pentadiene monomer unit of 1 to 60% by weight in addition to 0.1 to 50% by weight of the monomer unit derived from the tetracyclododecene compound. %, 1 to 30% by weight of an alicyclic monoolefin monomer unit having 4 to 6 carbon atoms, 0 to 50% by weight of an acyclic monoolefin monomer unit having 4 to 8 carbon atoms, and a single alicyclic diolefin. It contains 0 to 10% by weight of a molecular weight unit, 0 to 40% by weight of an aromatic monoolefin monomer unit, and 0 to 50% by weight of an aromatic monomer unit having a structure in which two or more cyclic structures are bonded. The hydrocarbon resin has a number average molecular weight (Mn) in the range of 250 to 2000, a Z average molecular weight (Mz) in the range of 1,000 to 10,000, and a weight average molecular weight with respect to the number average molecular weight. The ratio (Mw / Mn) of is in the range of 1.0 to 4.0, and the ratio of the Z average molecular weight to the weight average molecular weight (Mz / Mw) is in the range of 1.0 to 4.0. preferable.
In the rubber composition of the present invention, the hydrocarbon resin is a tetracyclo [4.4.0.1 ^2,5 . ^17,10 ] It is preferable to contain a dodeca-3-ene unit.
In the rubber composition of the present invention, tetracyclo [4.4.0.1 ^2,5 .] In the monomer unit derived from the tetracyclododecene compound. ^{17 and 10} ] The ratio of dodeca-3-ene units is preferably 50% by weight or more.
In the rubber composition of the present invention, the hydrocarbon resin is preferably a hydride.
The rubber composition of the present invention preferably further contains silica.
The rubber composition of the present invention preferably further contains a silane coupling agent.
The rubber composition of the present invention preferably further contains a cross-linking agent.

Further, according to the present invention, there is provided a rubber crosslinked product obtained by crosslinking the above rubber composition.
Further, according to the present invention, there is provided a pneumatic tire characterized in that the above rubber composition or the above rubber crosslinked product is used for a tread.

According to the present invention, it is possible to provide a rubber composition capable of obtaining a rubber crosslinked product having good workability and an excellent balance between rolling resistance and wet grip performance.

The rubber composition of the present invention contains a diene-based rubber and a hydrocarbon resin, and the content of the hydrocarbon resin is 1 to 200 parts by mass with respect to 100 parts by mass of the diene-based rubber, and the hydrocarbon resin. Contains a monomer unit derived from a tetracyclododecene compound in a proportion of 0.1 to 50% by mass, has a weight average molecular weight (Mw) in the range of 500 to 4,000, and has a softening point of 80 to 80 to 4,000. It is within the range of 170 ° C. Hereinafter, each component of the rubber composition of the present invention will be described.

<Hydrocarbon resin>
The hydrocarbon resin used in the present invention contains a monomer unit derived from a tetracyclododecene compound in a proportion of 0.1 to 50% by weight, and has a weight average molecular weight (Mw) in the range of 500 to 4,000. Yes, the softening point is in the range of 80 to 170 ° C. The hydrocarbon resin used in the present invention can be produced, for example, by addition polymerization of a monomer mixture containing a tetracyclododecene compound and a copolymerizable monomer thereof.

The hydrocarbon resin used in the present invention may contain a monomer unit derived from the tetracyclododecene compound at a ratio of 0.1 to 50% by weight, and the content ratio is not particularly limited, but is preferable. It is 5 to 45% by weight, more preferably 10 to 40% by weight, still more preferably 15 to 35% by weight. In the present invention, by using a hydrocarbon resin containing a monomer unit derived from a tetracyclododecene compound in the above content ratio and having a weight average molecular weight (Mw) and a softening point within the above predetermined ranges. It is possible to obtain a rubber crosslinked product having an excellent balance between rolling resistance and wet grip performance while having excellent workability as a rubber composition.

In particular, as a result of diligent studies by the present inventors, the weight average molecular weight (Mw) is increased by containing the monomer unit derived from the tetracyclododecene compound in the hydrocarbon resin at a ratio of 0.1 to 50% by weight. ) And the softening point can be suitably controlled within the above range, whereby the rubber crosslinked product obtained when it is made into a rubber crosslinked product has rolling resistance and rolling resistance while making the rubber composition excellent in processability. It was found that the balance of wet grip performance can be excellent. If the content of the monomer unit derived from the tetracyclododecene compound is too small or too large, it becomes difficult to obtain an excellent balance between rolling resistance and wet grip performance of the obtained rubber crosslinked product. ..

As a tetracyclododecene compound for forming a monomer unit derived from a tetracyclododecene compound, tetracyclo [4.4.0.1 ^2,5 . 1 ^{7, 10} ] A compound having a dodeca-3-ene structure as a basic skeleton may be used, and specific examples thereof include tetracyclo [4.4.0.1 ^2,5 . ^{17 and 10} ] Dodeca-3-ene (tetracyclododecene), 8-methyl-tetracyclo [4.4.0.1 ^2,5 . ^{17 and 10} ] Dodeca-3-ene, 8-ethyl-tetracyclo [4.4.0.1 ^2,5 . ^{17 and 10} ] Dodeca-3-ene, 8-ethylidene-tetracyclo [4.4.0.1 ^2,5 . ^{17 and 10} ] Dodeca-3-ene, 8-vinyl-tetracyclo [4.4.0.1 ^2,5 . ^{17 and 10} ] Dodeca-3-ene, 8-propenyl-tetracyclo [4.4.0.1 ^2,5 . ^{17 and 10} ] Dodeca-3-en and the like. Only one type of tetracyclododecene compound may be used, or two or more types may be used in combination, but at least tetracyclo [4.4.0.1 ^2,5 . ^17.10 ] Dodeca-3-ene is preferably contained, and tetracyclo [4.4.0.1 ^2,5 .] In the tetracyclododecene compound. ^{17 and 10} ] It is more preferable that the proportion of dodeca-3-ene is 50% by weight or more. That is, as a monomer unit derived from the tetracyclododecene compound contained in the hydrocarbon resin used in the present invention, tetracyclo [4.4.0.1 ^2,5 . ^17.10 ] It is preferable to contain a dodeca-3-ene unit, and tetracyclo [4.4.0.1 ^2,5 .] In the monomer unit derived from the tetracyclododecene compound. ^{17 and 10} ] It is more preferable that the ratio of the dodeca-3-ene unit is 50% by weight or more.

The hydrocarbon resin used in the present invention may contain a monomer unit derived from the tetracyclododecene compound in a proportion of 0.1 to 50% by weight, and the monomer unit derived from the tetracyclododecene compound may be used. The monomer unit other than the above is not particularly limited, and any one can be contained. However, from the viewpoint of the processability of the rubber composition, the rolling resistance of the obtained rubber crosslinked product, and the wet grip performance, 1 , 3-Pentadiene monomer unit 1 to 60% by weight, alicyclic monoolefin monomer unit having 4 to 6 carbon atoms 1 to 30% by weight, acyclic monoolefin monomer unit having 4 to 8 carbon atoms An aromatic having a structure in which 0 to 50% by weight, an alicyclic diolefin monomer unit 0 to 10% by weight, an aromatic monoolefin monomer unit 0 to 40% by weight, and two or more cyclic structures are bonded. It preferably contains 0 to 50% by weight of the monomer unit.

The content ratio of the 1,3-pentadiene (piperylene) monomer unit in the hydrocarbon resin used in the present invention is preferably 1 to 60% by weight, more preferably 10 to 55% by weight, still more preferably 20 to 50% by weight. Weight%. By setting the content ratio of the 1,3-pentadiene monomer unit in the above range, the workability as a rubber composition is excellent, and the obtained rubber crosslinked product is excellent in the balance between rolling resistance and wet grip performance. Can be considered. The cis / trans isomer ratio in 1,3-pentadiene may be any ratio and is not particularly limited.

The alicyclic monoolefin having 4 to 6 carbon atoms for forming an alicyclic monoolefin monomer unit having 4 to 6 carbon atoms has one ethylenically unsaturated bond in its molecular structure and is non-aromatic. A hydrocarbon compound having a sex ring structure and having 4 to 6 carbon atoms may be used, and is not particularly limited, and specific examples thereof include cyclohexene, cyclopentene, cyclohexene, methylcyclobutene, and methylcyclopentene. Only one type of hydrocarbon compound having 4 to 6 carbon atoms may be used, or two or more types may be used in combination, but at least cyclopentene is preferably contained, and the hydrocarbon compound has 4 to 6 carbon atoms. The proportion of cyclopentene in the alicyclic monoolefin is preferably 50% by weight or more. That is, the ratio of the cyclopentene unit to the alicyclic monoolefin monomer unit having 4 to 6 carbon atoms contained in the hydrocarbon resin used in the present invention is preferably 50% by weight or more.

The content ratio of the alicyclic monoolefin monomer unit having 4 to 6 carbon atoms in the hydrocarbon resin used in the present invention is preferably 1 to 30% by weight, more preferably 5 to 30% by weight, still more preferably. It is 10 to 30% by weight, and even more preferably 20 to 30% by weight. By setting the content ratio of the alicyclic monoolefin monomer unit having 4 to 6 carbon atoms in the above range, the obtained rubber crosslinked product can be made more excellent in rolling resistance and wet grip performance.

An acyclic monoolefin having 4 to 8 carbon atoms for forming an acyclic monoolefin monomer unit having 4 to 8 carbon atoms has one ethylenically unsaturated bond in its molecular structure. A chain hydrocarbon compound having no ring structure and having 4 to 8 carbon atoms may be used, and is not particularly limited. Specific examples thereof include 1-butene, 2-butene, and isobutylene (2-methylpropene). Butenes; 1-pentene, 2-pentene, 2-methyl-1-butene, 3-methyl-1-butene, 2-methyl-2-butene and other butenes; 1-hexene, 2-hexene, 2- Hexenes such as methyl-1-pentene; heptenes such as 1-heptene, 2-heptene, 2-methyl-1-hexene; 1-octene, 2-octene, 2-methyl-1-heptene, diisobutylene (2) , 4,4-trimethylpentene-1 and 2,4,4-trimethylpentene-1) and other octenes; and the like. Only one type of acyclic monoolefin having 4 to 8 carbon atoms may be used, or two or more types may be used in combination, but at least from 2-methyl-2-butene, isobutylene and diisobutylene. It is preferable that at least one selected from the above group is contained, and the total amount of 2-methyl-2-butene, isobutylene and diisobutylene in the acyclic monoolefin having 4 to 6 carbon atoms accounts for 50% by weight. The above is more preferable. That is, the total ratio of 2-methyl-2-butene unit, isobutylene unit and diisobutylene unit in the acyclic monoolefin monomer unit having 4 to 6 carbon atoms contained in the hydrocarbon resin used in the present invention is It is preferably 50% by weight or more.

The content ratio of the acyclic monoolefin monomer unit having 4 to 8 carbon atoms in the hydrocarbon resin used in the present invention is preferably 0 to 50% by weight, more preferably 0 to 40% by weight, still more preferably. It is 1 to 30% by weight, and even more preferably 5 to 30% by weight. By containing the acyclic monoolefin monomer unit having 4 to 8 carbon atoms in the above ratio, the obtained rubber crosslinked product can be made excellent in rolling resistance and wet grip performance.

The alicyclic diolefin for forming an alicyclic diolefin monomer unit is a hydrocarbon compound having two or more ethylenically unsaturated bonds and a non-aromatic ring structure in its molecular structure. However, the specific examples thereof include, but are not limited to, a multimer of cyclopentadiene such as cyclopentadiene and dicyclopentadiene, and a multimer of methylcyclopentadiene and methylcyclopentadiene. Only one type of alicyclic diolefin may be used, or two or more types may be used in combination, but it is preferable that at least dicyclopentadiene is contained, and dicyclo in the alicyclic diolefin. More preferably, the proportion of pentadiene is 50% by weight or more. That is, the ratio of the dicyclopentadiene unit to the alicyclic diolefin monomer unit contained in the hydrocarbon resin used in the present invention is preferably 50% by weight or more.

The content ratio of the alicyclic diolefin monomer unit in the hydrocarbon resin used in the present invention is preferably 0 to 10% by weight, more preferably 0 to 7.5% by weight, still more preferably 0 to 5% by weight. %. By containing the alicyclic diolefin monomer unit in the above ratio, the obtained rubber crosslinked product can be made excellent in rolling resistance and wet grip performance.

The aromatic monoolefin for forming an aromatic monoolefin monomer unit is a hydrocarbon compound having one ethylenically unsaturated bond in its molecular structure and having an aromatic ring structure. Often, but not particularly limited, specific examples thereof include styrene, α-methylstyrene, vinyltoluene and the like. Only one type of aromatic monoolefin may be used, or two or more types may be used in combination, but it is preferable that at least styrene is contained, and the proportion of styrene in the aromatic monoolefin is 50. More preferably, it is by weight% or more. That is, the proportion of the styrene unit in the aromatic monoolefin monomer unit contained in the hydrocarbon resin used in the present invention is preferably 50% by weight or more.

The content ratio of the aromatic monoolefin monomer unit in the hydrocarbon resin used in the present invention is preferably 0 to 40% by weight, more preferably 0 to 35% by weight, still more preferably 0 to 30% by weight. .. By containing the aromatic monoolefin monomer unit in the above ratio, the obtained rubber crosslinked product can be made excellent in rolling resistance and wet grip performance.

An aromatic monomer having a structure in which two or more cyclic structures are bonded for forming an aromatic monomer unit having a structure in which two or more cyclic structures are bonded includes an aromatic ring structure. It may be a hydrocarbon compound having two or more ring structures, and is not particularly limited, but specific examples thereof include a compound having a naphthalene skeleton such as naphthalene, a compound having a fluorene skeleton such as fluorene, and a biphenyl skeleton such as biphenyl. Examples thereof include compounds having an anthracene skeleton such as anthracene, compounds having a phenanthrene skeleton such as phenanthrene, compounds having an inden skeleton such as inden, and compounds having a benzothiophene skeleton such as benzothiophene. Only one type of aromatic monomer having a structure in which two or more cyclic structures are bonded may be used, or two or more types may be used in combination.

In the hydrocarbon resin used in the present invention, the content ratio of the aromatic monomer unit having a structure in which two or more cyclic structures are bonded is preferably 0 to 50% by weight, more preferably 0 to 40% by weight, and further. It is preferably 0 to 30% by weight. By containing the aromatic monomer unit having a structure in which two or more cyclic structures are bonded in the above ratio, the obtained rubber crosslinked product can be made excellent in rolling resistance and wet grip performance.

Further, the hydrocarbon resin used in the present invention may contain units of other monomers other than the above-mentioned monomer units. The other monomer may be a monomer copolymerizable with each monomer containing the above-mentioned tetracycloheptene compound, and is not particularly limited, but for example, 1,3-butadiene, 1,2. -Acyclic polyenes other than 1,3-pentadiene such as butadiene, isoprene, 1,3-hexadiene, and 1,4-pentadiene; alicyclic monoolefins having 7 or more carbon atoms such as cycloheptene; ethylene, propylene, nonene, etc. Acyclic monoolefins other than those having 4 to 8 carbon atoms; Only one type of these may be used, or two or more types may be used in combination. The content ratio of the unit of the other monomer in the hydrocarbon resin used in the present invention is preferably 0 to 30% by weight, more preferably 0 to 25% by weight, still more preferably 0 to 20% by weight.

The hydrocarbon resin used in the present invention can be produced, for example, by addition polymerization of a monomer mixture containing a tetracyclododecene compound and each of the above-mentioned monomers. The method of addition polymerization is not particularly limited, and a method known as an addition polymerization method for producing a hydrocarbon resin can be selected. Further, after the hydrocarbon resin is obtained by addition polymerization of the monomer mixture, a part or all of the unsaturated bonds remaining in the polymer molecular structure of the hydrocarbon resin are saturated by the hydrogenation reaction (hydrogenation). It may be a hydrogenated product.

The weight average molecular weight (Mw) of the hydrocarbon resin used in the present invention may be in the range of 500 to 4,000 and is not particularly limited, but is preferably in the range of 750 to 3,500, more preferably 1,000 to. It is in the range of 3,000. If the weight average molecular weight (Mw) of the hydrocarbon resin is too small, the obtained rubber crosslinked product will have an inferior balance between rolling resistance and wet grip performance. On the other hand, if the weight average molecular weight (Mw) of the hydrocarbon resin is too large, the processability of the rubber composition becomes inferior.

The number average molecular weight (Mn) of the hydrocarbon resin used in the present invention is preferably in the range of 250 to 2,000, more preferably in the range of 375 to 1,750, and further preferably in the range of 500 to 1,500. is there. When the number average molecular weight (Mn) of the hydrocarbon resin is within the above range, the obtained rubber crosslinked product can be made excellent in rolling resistance and wet grip performance.

The Z average molecular weight (Mz) of the hydrocarbon resin used in the present invention is preferably in the range of 1,000 to 10,000, more preferably in the range of 1,500 to 8,500, and even more preferably in the range of 2,000 to 2,000. It is in the range of 7,000. When the Z average molecular weight (Mz) of the hydrocarbon resin is within the above range, the obtained rubber crosslinked product can be made excellent in rolling resistance and wet grip performance.

The hydrocarbon resin used in the present invention has a weight average molecular weight ratio (Mw / Mn) to a number average molecular weight preferably in the range of 1.0 to 4.0, more preferably 1.2 to 3.5. The range, more preferably 1.4 to 3.0. When this ratio is within the above range, the obtained rubber crosslinked product can be made more excellent in rolling resistance and wet grip performance.

The hydrocarbon resin used in the present invention has a ratio of Z average molecular weight to weight average molecular weight (Mz / Mw) preferably in the range of 1.0 to 4.0, more preferably 1.2 to 3.5. The range, more preferably 1.4 to 3.0. When this ratio is within the above range, the obtained rubber crosslinked product can be made more excellent in rolling resistance and wet grip performance.

In the present invention, the weight average molecular weight (Mw), Z average molecular weight (Mz), and number average molecular weight (Mn) of the hydrocarbon resin are determined as polystyrene-equivalent values measured by high performance liquid chromatography. The weight average molecular weight (Mw), Z average molecular weight (Mz), number average molecular weight (Mn), and their ratios (Mw / Mn, Mz / Mw) of the hydrocarbon resin are simply derived from the tetracyclododecene compound. Control by adjusting the composition of each monomer after setting the molecular weight unit to a ratio of 0.1 to 50% by weight, or by adjusting the production conditions in the method for producing a hydrocarbon resin described later. Can be done.

The softening point of the hydrocarbon resin used in the present invention may be in the range of 80 ° C. to 170 ° C., and is not particularly limited, but is preferably 85 to 160 ° C., more preferably 90 to 150 ° C. If the softening point of the hydrocarbon resin is too low or too high, the obtained rubber crosslinked product will have an inferior balance between rolling resistance and wet grip performance. As for the softening point of the hydrocarbon resin, the composition of each monomer may be adjusted after setting the ratio of the monomer unit derived from the tetracyclododecene compound to 0.1 to 50% by weight, or the hydrocarbon described later may be used. In the method for producing a hydrogen resin, it can be controlled by adjusting the production conditions.

Further, the hydrocarbon resin used in the present invention may be a hydride in which some or all of the unsaturated bonds remaining in the polymer molecular structure of the hydrocarbon resin are saturated by a hydrogenation reaction (hydrogenation). Good.

As a method for producing a hydrocarbon resin used in the present invention, a monomer mixture containing a tetracyclododecene compound and each of the above-mentioned monomers is addition-polymerized to obtain a weight average molecular weight (Mw) and a softening point. As long as a hydrocarbon resin as in the above range can be obtained, the present invention is not particularly limited, but for example, it can be produced by addition polymerization using a Friedel-Crafts type cationic polymerization catalyst, and in particular, Lewis. A method by addition polymerization using the acid catalyst (A) is preferable.

The Lewis acid catalyst (A) is not limited, but is preferably a metal halide, and is a halide of an element belonging to Group III of the Periodic Table or a complex thereof from the viewpoint of having good reaction activity. preferable. Specific examples of such a Lewis acid catalyst include aluminum trichloride (AlCl ₃ ), aluminum bromide (AlBr ₃ ), gallium trichloride (GaCl ₃ ), and boron trifluorinated diethyl ether complex (BF ₃ , Et _2). O) and the like can be mentioned. _{Among them, AlCl 3} or BF ₃ · Et ₂ O is preferably used from the viewpoint of versatility and the like. Only one type of Lewis acid catalyst (A) may be used, or two or more types may be used in combination.

The amount of the Lewis acid catalyst (A) used is not particularly limited, but is preferably 0.05 to 10 parts by weight, more preferably 0.1 to 5 parts by weight, based on 100 parts by weight of the monomer mixture used for the polymerization. Is.

Further, the Lewis acid catalyst (A) is adjacent to a halogenated hydrocarbon (B1) in which a halogen atom is bonded to a tertiary carbon atom and a carbon-carbon unsaturated bond in that the polymerization activity can be further enhanced. It may be used in combination with at least one halogenated hydrocarbon (B) selected from halogenated hydrocarbons (B2) in which a halogen atom is bonded to a carbon atom.

Specific examples of the halogenated hydrocarbon (B1) in which a halogen atom is bonded to a tertiary carbon atom include t-butyl chloride, t-butyl bromide, 2-chloro-2-methylbutane, and triphenylmethyl chloride. Among these, t-butyl chloride is particularly preferably used because it has an excellent balance between activity and ease of handling. Specific examples of halogenated hydrocarbons (B2) in which a halogen atom is bonded to a carbon atom adjacent to a carbon-carbon unsaturated bond include benzyl chloride, benzyl bromide, (1-chloroethyl) benzene, allyl chloride, and 3-chloro-. Examples thereof include 1-propyne, 3-chloro-1-butene, 3-chloro-1-butyne, and silica skin chloride. Among these, benzyl chloride is preferably used because it has an excellent balance between activity and ease of handling. Only one type of halogenated hydrocarbon (B) may be used, or two or more types may be used in combination.

The amount of the halogenated hydrocarbon (B) used is not particularly limited, but is preferably in the range of 0.05 to 50, more preferably in the range of 0.1 to 10, in terms of the molar ratio to the Lewis acid catalyst (A). ..

In carrying out the polymerization reaction, the order in which each component of the monomer mixture and the polymerization catalyst is added to the polymerization reactor is not particularly limited and may be added in any order, but from the viewpoint of satisfactorily controlling the polymerization reaction. To a part of the monomer component constituting the monomer mixture and a part of the monomer component constituting the monomer mixture by adding the Lewis acid catalyst (A) to the polymerization reactor in advance. After contacting the Lewis acid catalyst (A) in advance, it is preferable to add the rest of the monomer components constituting the monomer mixture to the polymerization reactor to start the polymerization reaction. In this case, at least an alicyclic monoolefin having 4 to 6 carbon atoms is used as a part of the monomer components constituting the monomer mixture, and is added to the Lewis acid catalyst (A) and the polymerization reactor in advance. Then, after the alicyclic monoolefin having 4 to 6 carbon atoms and the Lewis acid catalyst (A) are brought into contact with each other in advance, the remainder of the monomer component constituting the monomer mixture is added to the polymerization reactor. , It is more preferable to start the polymerization reaction.

When a halogenated hydrocarbon (B) is used in addition to the Lewis acid catalyst (A), the monomer mixture and the Lewis acid catalyst (A) are added to the polymerization reactor to carry out the polymerization reaction. After the start, it is preferable to add the halogenated hydrocarbon (B) to the polymerization reactor. Alternatively, the monomer mixture, the Lewis acid catalyst (A), a part of the halogenated hydrocarbon (B) and a part of the halogenated hydrocarbon (B) are added to the polymerization reactor to initiate the polymerization reaction, and then the remainder of the halogenated hydrocarbon (B). Is also preferably added to the polymerization reactor.

From the viewpoint of better controlling the polymerization reaction, it is preferable to add a solvent to the polymerization reaction system to carry out the polymerization reaction. The type of solvent is not particularly limited as long as it does not inhibit the polymerization reaction, but saturated aliphatic hydrocarbons or aromatic hydrocarbons are preferable. Examples of saturated aliphatic hydrocarbons used as a solvent include n-pentane, n-hexane, 2-methylpentane, 3-methylpentane, n-heptane, 2-methylhexane, 3-methylhexane, and 3-ethylpentane. , 2,2-Dimethylpentane, 2,3-dimethylpentane, 2,4-dimethylpentane, 3,3-dimethylpentane, 2,2,3-trimethylbutane, 2,2,4-trimethylpentane, etc. 5 to 10 chain saturated aliphatic hydrocarbons; examples include cyclic saturated aliphatic hydrocarbons having 5 to 10 carbon atoms such as cyclopentane, cyclohexane, cycloheptane, and cyclooctane. Examples of the aromatic hydrocarbon used as the solvent include aromatic hydrocarbons having 6 to 10 carbon atoms such as benzene, toluene and xylene. One type of solvent may be used alone, or two or more types may be used as a mixed solvent. The amount of the solvent used is not particularly limited, but is preferably 10 to 1000 parts by weight, more preferably 50 to 500 parts by weight, based on 100 parts by weight of the monomer mixture used in the polymerization reaction. In addition, for example, a mixture of an addition-polymerizable component and a non-addition-polymerizable component, such as a mixture of cyclopentane and cyclopentene derived from the C5 distillate, is added to the polymerization reaction system, and the amount of the addition-polymerizable component is a single amount. It is also possible to use it as a component of the body mixture and use the non-additionally polymerizable component as a solvent.

The polymerization temperature at the time of carrying out the polymerization reaction is not particularly limited, but is preferably 85 ° C. or lower, more preferably −20 to 85 ° C., and even more preferably 0 to 65 ° C. If the polymerization temperature is too low, the polymerization activity may decrease and the productivity may be deteriorated, and if the polymerization temperature is too high, the hue of the obtained hydrocarbon resin may be inferior. The pressure at which the polymerization reaction is carried out may be under atmospheric pressure or under pressure. The polymerization reaction time can be appropriately selected, but is usually selected in the range of 10 minutes to 12 hours, preferably 30 minutes to 6 hours.

The polymerization reaction can be stopped by adding a polymerization terminator such as methanol, an aqueous solution of sodium hydroxide, or an aqueous solution of ammonia to the polymerization reaction system when the desired polymerization conversion rate is obtained. The solvent-insoluble catalyst residue produced when the polymerization catalyst is inactivated by adding a polymerization inhibitor may be removed by filtration or the like. After the polymerization reaction is stopped, the unreacted monomer and solvent are removed, and the low molecular weight oligomer component is further removed by steam distillation or the like and cooled to obtain a solid hydrocarbon resin.

Further, with respect to the hydrocarbon resin used in the present invention thus obtained, if necessary, a part or all of the unsaturated bonds remaining in the polymer molecular structure of the hydrocarbon resin is hydrogenated (hydrogenation). May be saturated with hydrogenated product.

The hydrogenation reaction method for carrying out a hydrogenation reaction on a hydrocarbon resin is not particularly limited, but a known method can be used without limitation. For example, a method of contacting with hydrogen in the presence of a nickel catalyst, etc. Can be mentioned. The nickel catalyst is not particularly limited, but from the viewpoint of high reactivity, a catalyst containing a compound supporting nickel as a metal as a main component in a supported inorganic compound as a carrier is preferable. Specific examples of the supported inorganic compound as a carrier include silica, alumina, boria, silica-alumina, diatomaceous earth, clay, clay, magnesia, magnesia-silica (silica-magnesium oxide), titania, and zirconia.

<Diene rubber>
The rubber composition of the present invention contains a diene-based rubber in addition to the above-mentioned hydrocarbon resin. The diene rubber is not particularly limited as long as it can be blended with a hydrocarbon resin. Examples of such diene rubber include diene rubber described in JP-A-2015-189873, and specific examples thereof include natural rubber (NB), isoprene rubber (IR), and butadiene rubber (). BR), styrene-butadiene copolymer rubber (SBR), ethylene-propylene-dienter polymer (EPDM) and the like can be mentioned, and among them, styrene-butadiene copolymer rubber, butadiene rubber and the like are preferable. .. By using the above-mentioned diene-based rubber, it is possible to make the rubber crosslinked product excellent in the balance between rolling resistance and wet grip performance while making the rubber composition excellent in processability. The diene rubber may be used alone or in combination of two or more.

Further, the diene rubber in the present invention is not particularly limited in its molecular weight and microstructure, and may be terminal-modified with an amine, amide, silyl, alkoxysilyl, carboxyl, hydroxyl group or the like, or may be epoxidized. .. Further, the diene-based rubber in the present invention may be hydrogenated, but is preferably non-hydrogenated.

In the rubber composition of the present invention, the blending ratio of the diene-based rubber and the above-mentioned hydrocarbon resin may be 1 to 200 parts by mass of the hydrocarbon resin with respect to 100 parts by mass of the diene-based rubber. It is preferably blended in an amount of 70 parts by mass, more preferably 3 to 35 parts by mass. If the blending amount of the hydrocarbon resin is too small, the processability as a rubber composition will be inferior, while if it is too large, the obtained rubber crosslinked product will have an inferior balance between rolling resistance and wet grip performance. turn into.

The rubber composition of the present invention may consist only of a diene-based rubber and the above-mentioned hydrocarbon resin, but may further contain other components. Other components that can be contained in the rubber composition of the present invention include, for example, fillers, silane coupling agents, cross-linking agents, cross-linking accelerators, cross-linking activators, antioxidants, antioxidants, activators, process oils. , Plasticizers, lubricants, tackifiers, etc., and other compounding agents can be blended in required amounts.

As the filler that can be blended in the rubber composition of the present invention, those generally used in the rubber composition can be used, for example, carbon black, clay, diatomaceous earth, silica, talc, barium sulfate, calcium carbonate, etc. Inorganic hollow fillers such as magnesium carbonate, metal oxides, mica, aluminum hydroxide, various metal powders, wood powders, glass powders, ceramic powders, glass balloons, silica balloons; polystyrene, vinylidene fluoride, vinylidene fluoride copolymers And the like, organic hollow fillers and the like can be mentioned.

Examples of silica include dry white carbon, wet white carbon, colloidal silica, and precipitated silica. Among these, a wet method white carbon containing hydrous silicic acid as a main component is preferable. Further, a carbon-silica dual phase filler in which silica is supported on the surface of carbon black may be used. These silicas can be used alone or in combination of two or more. The nitrogen adsorption specific surface area of the silica used (measured by the BET method according to ASTM D3037-81) is preferably 100 to 400 m ² / g, more preferably 150 to 350 m ² / g. The pH of silica is preferably pH 5-10.

The blending amount of silica in the rubber composition of the present invention is preferably 10 to 200 parts by mass, more preferably 20 to 150 parts by mass, and further preferably 30 parts by mass with respect to 100 parts by mass of the rubber component in the rubber composition. ~ 75 parts by mass. By setting the blending amount of silica in the above range, the obtained rubber crosslinked product can be made more excellent in rolling resistance and wet grip performance.

When silica is used as the filler, it is preferable to use a silane coupling agent in combination. Examples of the silane coupling agent include vinyl triethoxysilane, β- (3,4-epoxycyclohexyl) ethyltrimethoxysilane, N- (β-aminoethyl) -γ-aminopropyltrimethoxysilane, and 3-octatio-. 1-propyl-triethoxysilane, bis (3- (triethoxysilyl) propyl) disulfide, bis (3- (triethoxysilyl) propyl) tetrasulfide, γ-trimethoxysilylpropyl dimethylthiocarbamyltetrasulfide, and γ -Trimethoxysilylpropylbenzothiaziltetrasulfide and the like can be mentioned. These silane coupling agents can be used alone or in combination of two or more. The blending amount of the silane coupling agent is preferably 0.1 to 30 parts by mass, and more preferably 1 to 15 parts by mass with respect to 100 parts by mass of silica.

Examples of carbon black include furnace black, acetylene black, thermal black, channel black, and graphite. These carbon blacks can be used alone or in combination of two or more. The blending amount of carbon black is usually 120 parts by mass or less with respect to 100 parts by mass of the rubber component in the rubber composition.

Further, the filler may be used alone or in combination of two or more. For example, silica and carbon black can be mixed and used as the filler.

The content of the filler other than silica and carbon black may be as long as the effect of the present invention can be obtained, and can be, for example, 120 parts by mass or less with respect to 100 parts by mass of the rubber component.

The cross-linking agent is not particularly limited, and examples thereof include sulfur, sulfur halide, organic peroxides, quinonedioximes, organic polyvalent amine compounds, and alkylphenol resins having a methylol group. Of these, sulfur is preferably used. The amount of the cross-linking agent blended is preferably 0.1 to 15 parts by mass, more preferably 0.5 to 5 parts by mass, and particularly preferably 1 to 4 parts by mass with respect to 100 parts by mass of the rubber component in the rubber composition. Is.

When sulfur or a sulfur-containing compound is used as the cross-linking agent, it is preferable to use a cross-linking accelerator and a cross-linking activator together. Examples of the cross-linking accelerator include a sulfenamide-based cross-linking accelerator; a guanidine-based cross-linking accelerator; a thiourea-based cross-linking accelerator; a thiazole-based cross-linking accelerator; a thiuram-based cross-linking accelerator; Crosslink accelerators; and the like. Among these, those containing a sulfenamide-based cross-linking accelerator are preferable. These cross-linking accelerators may be used alone or in combination of two or more. The amount of the cross-linking accelerator to be blended is preferably 0.1 to 15 parts by mass, more preferably 0.5 to 5 parts by mass, and particularly preferably 1 to 4 parts by mass with respect to 100 parts by mass of the rubber component in the rubber composition. It is a department.

Examples of the cross-linking activator include higher fatty acids such as stearic acid; zinc oxide; and the like. These cross-linking activators may be used alone or in combination of two or more. The blending amount of the cross-linking activator is preferably 0.05 to 20 parts by mass, particularly preferably 0.5 to 15 parts by mass with respect to 100 parts by mass of the rubber component in the rubber composition.

Further, if desired, an antiaging agent such as an amine-based stabilizer, a phenol-based stabilizer, a phosphorus-based stabilizer, or a sulfur-based stabilizer may be added to the rubber composition of the present invention. The amount of the anti-aging agent added may be appropriately determined according to the type and the like.

Further, an antioxidant may be added to the rubber composition of the present invention, if necessary. The antioxidant is not particularly limited, but for example, pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate], octadecyl-3- (3,5-di-t). Hindered phenolic compounds such as -butyl-4-hydroxyphenyl) propionate, 2,6-di-t-butyl-p-cresol, di-t-butyl-4-methylphenol; dilaurylthiopropionate and the like. Thiodicarboxylate esters; phosphites such as tris (nonylphenyl) phosphite; and the like. The antioxidant may be used alone or in combination of two or more. The content of the antioxidant is not particularly limited, but is preferably 10 parts by mass or less, and more preferably 0.05 to 5 parts by mass with respect to 100 parts by mass of the rubber component in the rubber composition.

Further, the rubber composition of the present invention may contain a resin in addition to the diene-based rubber and the above-mentioned hydrocarbon resin. By blending the resin, it is possible to impart adhesiveness to the rubber composition and enhance the dispersibility of the filler in the rubber composition. As a result, further improvement in rolling resistance and wet grip performance of the obtained rubber crosslinked product can be expected. Further, the processability of the rubber composition can be improved as an effect similar to that of the plasticizer. Examples of the resin include C9-based petroleum resin, dicyclopentadiene-based resin, terpene-based resin, terpene phenol resin, aromatic-modified terpene resin, alkylphenol-acetylene resin, rosin-based resin, rosin ester resin, inden-based resin, and inden. Examples thereof include C9-based resin, α-methylstyrene / inden copolymer resin, kumaron-inden resin, farnesene-based resin, and polylymonen resin contained. These resins may be modified or hydrogenated. These resins may be used alone or in combination of two or more. The blending amount of the resin is preferably 25 parts by mass or less with respect to 100 parts by mass of the rubber component in the rubber composition.

In the method for producing a rubber composition of the present invention, each component may be kneaded according to a conventional method. For example, a component excluding heat-unstable components such as a cross-linking agent and a cross-linking accelerator, a diene-based rubber, and a hydrocarbon may be used. After kneading the resin, a heat-unstable component such as a cross-linking agent or a cross-linking accelerator can be kneaded into the kneaded product to obtain a desired rubber composition. The kneading temperature at the time of kneading the components excluding the heat-unstable component, the diene rubber, and the hydrocarbon resin is preferably 80 to 200 ° C., more preferably 120 to 180 ° C., and the kneading time is It is preferably 30 seconds to 30 minutes. Further, the kneading of the kneaded product and the heat-unstable component is preferably performed after cooling to 100 ° C. or lower, more preferably 80 ° C. or lower.

By using the rubber composition of the present invention, it is possible to obtain an excellent rubber crosslinked product with a balance between rolling resistance and wet grip performance. Taking advantage of these characteristics, the rubber composition of the present invention is preferably used as a material for each part of a tire such as a tread (cap tread, base tread), carcass, sidewall, and bead part of the tire. However, in various tires such as all-season tires, high-performance tires, and studless tires, it can be suitably used for each part of the tire such as a tread, a carcass, a sidewall, and a bead part. It can be used particularly preferably, and it is particularly preferable to use it for a cap tread.

<Rubber cross-linked product>
The rubber crosslinked product of the present invention is obtained by cross-linking the above-mentioned rubber composition of the present invention.
The rubber crosslinked product of the present invention is formed by using the rubber composition of the present invention, for example, by a molding machine corresponding to a desired shape, for example, an extruder, an injection molding machine, a compressor, a roll, or the like, and is heated. It can be produced by carrying out a cross-linking reaction and fixing the shape as a rubber cross-linked product. In this case, cross-linking may be performed after molding in advance, or cross-linking may be performed at the same time as 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, particularly preferably 3 minutes to 6 hours. ..

Further, depending on the shape, size, etc. of the rubber crosslinked product, even if the surface is crosslinked, it may not be sufficiently crosslinked to the inside, so further heating may be performed for secondary crosslinking.

As the heating method, a general method used for cross-linking the rubber composition such as press heating, steam heating, oven heating, hot air heating and the like may be appropriately selected.

Since the rubber crosslinked product of the present invention thus obtained is obtained by using the rubber composition of the present invention described above, it is more excellent in the balance between rolling resistance and wet grip performance.

The rubber crosslinked product of the present invention is used as a material for each part of a tire such as a tread (cap tread, base tread), carcass, sidewall, bead part, etc. by utilizing its excellent rolling resistance and wet grip performance. In particular, in various tires such as all-season tires, high-performance tires, and studless tires, the tires can be suitably used for each part of the tire such as a tread, a carcass, a sidewall, and a bead portion. For example, a tire. It can be particularly preferably used for treads, and particularly preferably for cap treads.

Next, the pneumatic tire of the present invention will be described. The pneumatic tire of the present invention is characterized in that the above-mentioned rubber composition is used for a tread.

The tread is a tread using the above-mentioned rubber composition, that is, one formed by using the above-mentioned rubber composition, and is usually a rubber cross-linking of the present invention formed by cross-linking the above-mentioned rubber composition of the present invention. It includes things.

The pneumatic tire may have a tread formed by using the rubber composition, and other parts may also be formed by using the rubber composition.

The tread formed by using the above rubber composition may be a part of the tread or the whole tread, but preferably contains at least a cap tread.

Further, as the method for producing a pneumatic tire of the present invention, any method can be used as long as it can produce a pneumatic tire having a tread formed by using the above composition, and a known method for producing a pneumatic tire can be used. it can.

Hereinafter, the present invention will be described based on more detailed examples, but the present invention is not limited to these examples. Regarding the following, "parts" and "%" are based on mass unless otherwise specified.
The test methods performed in this example and the comparative example are as follows.

[Softening point (° C)]
The softening point of the sample hydrocarbon resin was measured according to JIS K 2207.

[Number average molecular weight, weight average molecular weight, Z average molecular weight, and molecular weight distribution]
Gel permeation chromatography analysis is performed on the hydrocarbon resin as a sample to obtain the number average molecular weight (Mn), weight average molecular weight (Mw), and Z average molecular weight (Mz) of standard polystyrene conversion values, and the molecular weight distribution. Is shown by the ratio of Mw / Mn and the ratio of Mz / Mw. For gel permeation chromatography analysis, "HLC-8320GPC" manufactured by Tosoh Co., Ltd. was used as a measuring device, and three columns "TSKgel SuperMultipore HZ" manufactured by Tosoh Co., Ltd. were linked, and tetrahydrofuran was used as a solvent. , 40 ° C., at a flow rate of 1.0 ml / min.

[Moony Viscosity (ML1 + 4)]
The rubber composition as a sample was measured under the following conditions according to JIS K 630-1: 2001. This characteristic is shown by an index with the reference sample (Comparative Example 1 described later) as 100. It can be judged that the smaller the value of Mooney viscosity, the better the workability.
-Test temperature: 100 ° C
・ Rotor type: L type ・ Test machine used: Shimadzu Mooney Biscometer SMV-300J manufactured by Shimadzu Corporation

[Tensile strength (MPa) and elongation (%)]
With respect to the test piece of the rubber crosslinked product as a sample, the tensile strength (tensile stress (MPa)) and the elongation (elongation (%)) were measured under the following conditions according to JIS K 6251: 2010. These characteristics are shown by an index with the reference sample (Comparative Example 1 described later) as 100. It can be judged that the larger the value, the better the tensile strength and elongation.
-Test piece preparation method: After sheet preparation by press cross-linking, punching processing-Test piece shape: Dumbbell-shaped No. 3 type-Test piece collection direction: Parallel to the row-Number of test pieces: 3
・ Measurement temperature: 23 ° C
-Test speed: 500 mm / min
-Testing machine used: TENSOMETER 10k manufactured by ALPHA TECHNOLOGIES
・ Testing machine capacity: Load cell type 1kN

[Loss tangent tan δ]
For the test piece of the rubber crosslinked product as a sample, the loss tangent tan δ at 0 ° C. and 60 ° C. was measured under the conditions of dynamic strain 0.5% and 10 Hz under the following measurement conditions according to JIS K 7244-4. .. This characteristic is shown by an index with the reference sample (Comparative Example 1 described later) as 100. It can be judged that the higher the loss tangent tan δ at 0 ° C, the better the wet grip performance, and the lower the loss tangent tan δ at 60 ° C, the better the rolling resistance (the lower the loss tangent tan δ at 60 ° C, the better the rolling resistance. It can be judged that it is low).
Measurement item: Dynamic storage modulus E'
: Dynamic loss elastic modulus E "
: Loss tangent tan δ
-Sample preparation method: Punching from the sheet-Test piece shape: Length 50 mm x Width 2 mm x Thickness 2 mm
・ Number of test pieces: 1
・ Distance between clamps: 20 mm

[Manufacturing Example 1]
42.7 parts of cyclopentane, 14.8 parts of cyclopentene and 0.5 part of toluene were charged into the polymerization reactor, the temperature was raised to 55 ° C., and then 1.2 parts of aluminum chloride was added. Subsequently, tetracyclododecene (tetracyclo ^[4.4.0.1 2,5 ^{.1 7,10]} dodeca-3-ene) 24.6 parts of 1,3-pentadiene 41.1 parts of cyclopentene 15.2 A mixture consisting of 2.2 parts of isobutylene, 1.2 parts of diisobutylene, 0.4 parts of dicyclopentadiene, 0.5 parts of C4-C6 unsaturated hydrocarbon, and 10.3 parts of C4-C6 saturated hydrocarbon. Was continuously added to the polymerization reactor while maintaining the temperature of 75 ° C. for 60 minutes to carry out the polymerization. Then, an aqueous sodium hydroxide solution was added to the polymerization reactor to stop the polymerization reaction. The polymerization conversion rate at this time was 85%, and the composition of the obtained polymer was almost the same as the proportion of the components constituting the monomer mixture. The types and amounts of the components in the polymerization reactor during the polymerization reaction are the components constituting the monomer mixture (additionally polymerizable component), the components corresponding to the solvent (non-additionally polymerizable components), and the polymerization catalyst. They are classified and shown in Table 1. After removing the precipitate produced by the polymerization termination by filtration, the obtained polymer solution was placed in a distillation pot and heated in a nitrogen atmosphere to remove the polymerization solvent and the unreacted monomer. Then, at 240 ° C. or higher, the low molecular weight oligomer component was distilled off while blowing saturated water vapor. 1. Pentaerythritol tetrakis [3- (3,5-di-t-butyl-4-hydroxyphenyl) propionate] (BASF's "Irganox 1010") as an antioxidant for 100 parts of the molten resin. After adding 25 parts and mixing, the molten resin was taken out from the distillation pot and allowed to cool to room temperature to obtain the hydrocarbon resin of Production Example 1. The softening point, number average molecular weight (Mn), weight average molecular weight (Mw), Z average molecular weight (Mz), and molecular weight distribution (Mw / Mn and Mz / Mw) of the obtained hydrocarbon resin of Production Example 1 were measured. .. The results of these measurements are summarized in Table 1.

[Manufacturing Examples 2 to 8]
Hydrocarbon resins of Production Examples 2 to 8 were obtained in the same manner as in Production Example 1 except that the types and amounts of the components added to the polymerization reactor and the polymerization temperature were changed as shown in Table 1. .. The obtained hydrocarbon resins of Production Examples 2 to 8 were measured in the same manner as in Production Example 1. The results of these measurements are summarized in Table 1. In Production Examples 2 to 8, the composition of the obtained polymer was almost the same as the proportion of the components constituting the monomer mixture.

[Example 1]
Oil-expanded emulsified polymerized styrene-butadiene rubber (SBR) (trade name "Nipol 1739", manufactured by Nippon Zeon Co., Ltd., amount of bonded styrene: 40%, vinyl bond content of butadiene unit portion: 13.5 Mol%, weight average molecular weight: 690,000, molecular weight distribution (Mw / Mn): 3.98, glass transition temperature (Tg): -35 ° C., containing 37.5 parts of styrene oil with respect to 100 parts of rubber component. ) 96.3 parts (rubber component content: 70 parts, spreading oil content: 26.3 parts) and solution-polymerized butadiene rubber (BR) (trade name "Nipol BR1220", manufactured by Nippon Zeon, butadiene unit Vinyl bond content of the moiety: 2 mol%, weight average molecular weight: 490,000, molecular weight distribution (Mw / Mn): 2.52, Mooney viscosity (ML1 + 4,100 ° C.): 44, glass transition temperature (Tg):- (110 ° C.) 30 parts and kneading for 30 seconds, then silica (manufactured by Rhodia, trade name "Zeosil1165MP") 46.6 parts, carbon black (manufactured by Cabot Japan, trade name "N339") 5 parts, silane Coupling agent: 6 parts of bis [3- (triethoxysilyl) propyl] tetrasulfide (manufactured by Tegussa, trade name "Si69") and 10 parts of the hydrocarbon resin obtained in Production Example 1 are added for 90 seconds. After kneading, 23.4 parts of silica (manufactured by Rhodia, trade name "Zeosil1165MP"), 3 parts of zinc oxide, 2 parts of stearic acid, and anti-aging agent: N-phenyl-N'-(1,3-dimethylbutyl) -P-Phenylenediamine (manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd., trade name "Nocrack 6C") 2 parts is added, kneaded for another 90 seconds, and then process oil (manufactured by Shin Nihon Oil Co., Ltd., trade name "Aromax T" -DAE ") 5 copies were put in. Then, after kneading (primary kneading) at 145 to 155 ° C. for 60 seconds or more with 90 ° C. as a starting temperature, the kneaded product was discharged from the mixer.

The obtained kneaded product was cooled to room temperature, kneaded again in a Banbury type mixer for 2 minutes (secondary kneading) at a starting temperature of 90 ° C., and then the kneaded product was discharged from the mixer. The temperature of the kneaded product at the end of kneading was 145 ° C.

Next, in two rolls at 50 ° C., 1.7 parts of sulfur and a cross-linking accelerator: N-cyclohexyl-2-benzothiazolyl sulphenamide (CBS trade name "Noxeller CZ-G") were added to the obtained kneaded product. , 1.8 parts manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd., and 1.7 parts of diphenylguanidine (DPG trade name "Noxeller D", manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.) are added and kneaded (crosslinker kneading). After that, the sheet-shaped rubber composition was taken out.

The kneading conditions for the primary kneading, the secondary kneading, and the cross-linking agent kneading were as shown below.

(Kneading conditions for primary and secondary kneading)
・ Testing machine: Labplast Mill Banbury Mixer B-600 manufactured by Toyo Seiki Seisakusho Co., Ltd.
-Filling rate: 70-75 vol%
・ Rotor rotation speed: 50 rpm
・ Test start set temperature: 90 ° C

(Kneading conditions for cross-linking agent kneading)
・ Testing machine: Electric heating type high temperature roll machine manufactured by Ikeda Kikai Kogyo Co., Ltd. ・ Roll size: 6φ × 16
・ Front roll rotation speed: 24 rpm
・ Front-rear roll rotation ratio: 1: 1.22
・ Roll temperature: 50 ± 5 ℃
・ Number of turns: 2 times on each side ・ Rounding width: Roll spacing approx. 0.8 mm
・ Number of rounding: 5 times

[Examples 2 to 5 and Comparative Examples 1 to 3]
As shown in Table 2 below, a rubber composition was obtained in the same manner as in Example 1 except that the hydrocarbon resins obtained in Production Examples 2 to 8 were used instead of the hydrocarbon resins obtained in Production Example 1. ..

[Evaluation]
The rubber compositions obtained in Examples 1 to 5 and Comparative Examples 1 to 3 were press-crosslinked at a press pressure of about 8 MPa and a press temperature of 160 ° C. for 40 minutes, and then aged overnight in a thermostatic chamber at 23 ° C., and then 150 mm. A test piece of a crosslinked rubber product of × 150 mm × thickness 2 mm was prepared.

With respect to the rubber compositions and rubber crosslinked products obtained in Examples 1 to 5 and Comparative Examples 1 to 3, the Mooney viscosity of the rubber composition, the tensile strength (MPa), the elongation (%), and the loss tangent of the rubber crosslinked products. tan δ was measured. The results are shown in Table 2 below.

As shown in Tables 1 and 2, a rubber composition containing a diene-based rubber and a hydrocarbon resin, wherein the content of the hydrocarbon resin is 1 to 200 parts by mass with respect to 100 parts by mass of the diene-based rubber. The hydrocarbon resin contains a monomer unit derived from a tetracyclododecene compound in a proportion of 0.1 to 50% by weight, and has a weight average molecular weight (Mw) in the range of 500 to 4,000. The rubber composition having a softening point in the range of 80 to 170 ° C. has excellent workability, and the obtained rubber crosslinked product has an excellent balance between rolling resistance and wet grip performance, and further. It was also excellent in tensile strength and elongation (Examples 1 to 5).

On the other hand, when a rubber composition containing no monomer unit derived from the tetracyclododecene compound and containing a hydrocarbon resin having an excessively large weight average molecular weight (Mw) is used, the obtained rubber crosslinked product is obtained. Was inferior in rolling resistance and wet grip performance (Comparative Examples 1 and 2).
Further, when a rubber composition containing a hydrocarbon resin having a softening point too low and which does not contain a monomer unit derived from a tetracyclododecene compound is used, the obtained rubber crosslinked product has rolling resistance. And the balance of wet grip performance was inferior (Comparative Example 3).

Claims

A rubber composition containing a diene-based rubber and a hydrocarbon resin.
The content of the hydrocarbon resin is 1 to 200 parts by mass with respect to 100 parts by mass of the diene rubber.
The hydrocarbon resin is
It contains a monomer unit derived from a tetracyclododecene compound in a proportion of 0.1 to 50% by weight.
The weight average molecular weight (Mw) is in the range of 500 to 4,000.
A rubber composition having a softening point in the range of 80 to 170 ° C.
In addition to 0.1 to 50% by weight of the monomer unit derived from the tetracyclododecene compound, the hydrocarbon resin is added.
1,3-Pentadiene monomer unit 1-60% by weight,
Alicyclic monoolefin monomer unit with 4 to 6 carbon atoms 1 to 30% by weight,
Acyclic monoolefin monomer unit with 4 to 8 carbon atoms 0 to 50% by weight,
Alicyclic diolefin monomer unit 0-10% by weight,
Aromatic monoolefin monomer unit 0-40% by weight, and
Contains 0 to 50% by weight of an aromatic monomer unit having a structure in which two or more cyclic structures are bonded.
The hydrocarbon resin is
The number average molecular weight (Mn) is in the range of 250 to 2000,
The Z average molecular weight (Mz) is in the range of 1,000 to 10,000.
The ratio of the weight average molecular weight to the number average molecular weight (Mw / Mn) is in the range of 1.0 to 4.0.
The rubber composition according to claim 1, wherein the ratio of the Z average molecular weight to the weight average molecular weight (Mz / Mw) is in the range of 1.0 to 4.0.
The hydrocarbon resin, as a monomer unit derived from the tetracyclododecene compound, is tetracyclo [4.4.0.1 2,5 . 1 7, 10 ] The rubber composition according to claim 1 or 2, which contains a dodeca-3-ene unit.
In the monomer unit derived from the tetracyclododecene compound, tetracyclo [4.4.0.1 2,5 . 17.10 ] The rubber composition according to claim 3, wherein the ratio of the dodeca-3-ene unit is 50% by weight or more.
The rubber composition according to any one of claims 1 to 4, wherein the hydrocarbon resin is a hydride.
The rubber composition according to any one of claims 1 to 5, further containing silica.
The rubber composition according to any one of claims 1 to 6, further containing a silane coupling agent.
The rubber composition according to any one of claims 1 to 7, further containing a cross-linking agent.
A rubber crosslinked product obtained by cross-linking the rubber composition according to any one of claims 1 to 8.
A pneumatic tire using the rubber composition according to any one of claims 1 to 8 or the rubber crosslinked product according to claim 9 for a tread.