JP7255136B2 - Rubber composition and pneumatic tire using the same - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rubber composition, and more particularly to a rubber composition from which a cross-linked rubber having excellent rolling resistance and abrasion resistance can be obtained.

BACKGROUND ART In recent years, automobile tires are strongly required to have low fuel consumption from the viewpoint of environmental and resource problems, while from the viewpoint of safety, for example, improved wet grip performance is required. A crosslinked rubber composition in which silica is compounded as a filler in a rubber component (hereinafter, sometimes simply referred to as a crosslinked rubber) constitutes a tire compared to a crosslinked rubber composition in which carbon black is compounded. Rolling resistance is reduced when Therefore, by forming 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 into a conventional rubber component, the affinity between the rubber component and silica is insufficient, and these tend to separate, resulting in poor processability of the rubber composition before cross-linking. In addition, the rubber cross-linked product obtained by cross-linking these has a problem that the rolling resistance when constituting a tire is insufficient.

Therefore, in Patent Document 1, 1 to 30 parts by mass of a hydrocarbon resin and 80 parts by mass of silica are added to 100 parts by mass of a diene rubber for the purpose of improving workability, tire rolling resistance, and wet grip performance. parts to 200 parts by mass, wherein the hydrocarbon resin contains an aliphatic monomer unit and an aromatic monomer unit, and two or more of the aromatic monomer units The content in the aromatic monomer unit of the monomer unit having a structure in which the cyclic structure of is 50% by mass or more, the weight average molecular weight (Mw) is within the range of 700 to 6000, and A rubber composition has been proposed which is characterized by a softening point in the range of 80°C to 150°C.

However, Patent Document 1 does not discuss a rubber composition for obtaining a cross-linked rubber having excellent rolling resistance and abrasion resistance.

WO2018/101361

It is an object of the present invention to provide a rubber composition from which a cross-linked rubber having excellent rolling resistance and abrasion resistance can be obtained.

The inventors of the present invention conducted studies to achieve the above object, and found that a specific hydrocarbon resin was hydrogenated to a specific hydrogenation rate and a rubber composition containing a specific amount of silica. Then, it was found that a cross-linked rubber having excellent processability, excellent tensile strength, elongation and wet grip properties, and particularly excellent rolling resistance and abrasion resistance can be obtained, and the present invention was established. I came to complete it.

That is, according to the present invention, a rubber composition containing a diene rubber, a hydrocarbon resin hydride, and silica, wherein the content of the hydrocarbon resin hydride is is 1 to 30 parts by mass, the content of the silica is 80 to 200 parts by mass with respect to 100 parts by mass of the diene rubber, and the hydrocarbon resin hydride contains an aliphatic monomer unit and an aromatic It is obtained by hydrogenating a hydrocarbon resin containing a group monomer unit, the hydrogenation rate is in the range of 0.1 to 80%, and the weight average molecular weight (Mw) is 700 to 6,000 Within the range, a rubber composition is provided having a softening point within the range of 80-150°C.

In the rubber composition of the present invention, the hydrocarbon resin comprises 10 to 60% by mass of 1,3-pentadiene monomer units, 1 to 30% by mass of alicyclic monoolefin monomer units having 4 to 6 carbon atoms, 1 to 50% by mass of acyclic monoolefin monomer units having 4 to 8 carbon atoms, 0 to 10% by mass of alicyclic diolefin monomer units, and 0.1 to 50% by mass of said aromatic monomer units %, the hydrocarbon resin hydride has a number average molecular weight (Mn) in the range of 400 to 3,000 and a Z average molecular weight (Mz) in the range of 1,500 to 20,000, 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, and the ratio of the Z average molecular weight to the weight average molecular weight (Mz/Mw) is 1.0 to 4.0. is preferably within the range of
In the rubber composition of the present invention, the aromatic monomer preferably contains at least one selected from the group consisting of styrene compounds, indene compounds and C9 fractions.

Further, according to the present invention, there is provided a pneumatic tire using the above rubber composition for a tread.

ADVANTAGE OF THE INVENTION According to this invention, the rubber composition which can obtain the rubber crosslinked product excellent in rolling resistance and wear resistance can be provided.

Each component of the rubber composition of the present invention will be described below.

<Hydrocarbon resin hydride>
The hydrocarbon resin hydride used in the present invention is obtained by hydrogenating a hydrocarbon resin containing an aliphatic monomer unit and an aromatic monomer unit, and has a hydrogenation rate of 0.1 to 80%. , a weight average molecular weight (Mw) in the range of 700 to 6,000, and a softening point in the range of 80 to 150°C.

The hydrocarbon resin hydride used in the present invention is obtained by hydrogenating a hydrocarbon resin containing an aliphatic monomer unit and an aromatic monomer unit.
In the following, first, the hydrocarbon resin before hydrogenation (hereinafter sometimes simply referred to as hydrocarbon resin) will be described in detail, and then the hydrocarbon resin hydride obtained by hydrogenating this hydrocarbon resin will be described. ,explain.

<Hydrocarbon resin>
A hydrocarbon resin is a raw material resin before hydrogenation, and contains an aliphatic monomer unit and an aromatic monomer unit.

(Aliphatic monomer unit)
The aliphatic monomer for forming the aliphatic monomer unit may be any one containing no aromatic ring and containing at least an unsaturated hydrocarbon. Examples of such aliphatic monomers include , 1,3-pentadiene, alicyclic monoolefin monomers having 4 to 6 carbon atoms, acyclic monoolefin monomers having 4 to 8 carbon atoms, alicyclic diolefin monomers, etc. can.

The hydrocarbon resin contains, as aliphatic monomer units, a 1,3-pentadiene unit, an alicyclic monoolefin monomer unit having 4 to 6 carbon atoms and an acyclic monoolefin monomer having 4 to 8 carbon atoms. It preferably contains units, and in addition to these, may further contain alicyclic diolefin monomer units.

The content of the 1,3-pentadiene monomer unit in the hydrocarbon resin is preferably 10 to 60% by mass, more preferably 15 to 55% by mass, still more preferably 20 to 50% by mass, and particularly preferably is 25 to 48% by mass. By setting the content of the monomer unit derived from 1,3-pentadiene within the above range, the obtained crosslinked rubber can have higher rolling resistance and wear resistance. The cis/trans isomer ratio in 1,3-pentadiene may be any ratio and is not particularly limited.

A C4-6 alicyclic monoolefin is a C4-6 hydrocarbon compound having one ethylenically unsaturated bond and a non-aromatic ring structure in its molecular structure. Specific examples of alicyclic monoolefins having 4 to 6 carbon atoms include cyclobutene, cyclopentene, cyclohexene, methylcyclobutene and methylcyclopentene.

The content of the alicyclic monoolefin monomer unit having 4 to 6 carbon atoms in the hydrocarbon resin is preferably 1 to 30% by mass, more preferably 3 to 28% by mass, and still more preferably 5 to 30% by mass. 26% by weight, particularly preferably 7 to 25% by weight. By setting the content of the alicyclic monoolefin monomer unit having 4 to 6 carbon atoms within the above range, the rolling resistance and wear resistance of the obtained crosslinked rubber can be further enhanced.

As for the alicyclic monoolefin having 4 to 6 carbon atoms, the ratio of each compound corresponding to this may be any ratio and is not particularly limited, but it is preferable that at least cyclopentene is included, and 4 carbon atoms It is more preferable that the ratio of cyclopentene in the alicyclic monoolefin of 1 to 6 is 50% by mass or more.

Acyclic monoolefins having 4 to 8 carbon atoms are chain hydrocarbon compounds having 4 to 8 carbon atoms which have one ethylenically unsaturated bond in their molecular structure and do not have a ring structure. Specific examples of acyclic monoolefins having 4 to 8 carbon atoms include butenes such as 1-butene, 2-butene and isobutylene (2-methylpropene); 1-pentene, 2-pentene, 2-methyl-1 -pentenes such as butene, 3-methyl-1-butene and 2-methyl-2-butene; hexenes such as 1-hexene, 2-hexene and 2-methyl-1-pentene; 1-heptene and 2-heptene , 2-methyl-1-hexene and other heptenes; 1-octene, 2-octene, 2-methyl-1-heptene, diisobutylene (2,4,4-trimethyl-1-pentene and 2,4,4- octenes such as trimethyl-1-pentene);

The content of the acyclic monoolefin monomer unit having 4 to 8 carbon atoms in the hydrocarbon resin is preferably 1 to 50% by mass, more preferably 5 to 45% by mass, and still more preferably 10 to 50% by mass. 42% by weight, particularly preferably 15 to 40% by weight. By setting the content of the acyclic monoolefin monomer unit having 4 to 8 carbon atoms within the above range, the rolling resistance and wear resistance of the resulting crosslinked rubber can be further enhanced.

As for the acyclic monoolefin having 4 to 8 carbon atoms, the ratio of each corresponding compound (including isomers) may be any ratio and is not particularly limited, but at least 2-methyl-2-butene , isobutylene, and diisobutylene, and 2-methyl-2-butene, isobutylene, and diisobutylene in the acyclic monoolefin having 4 to 8 carbon atoms. More preferably, the proportion of the total amount is 50% by mass or more.

Moreover, the hydrocarbon resin used in the present invention may contain an alicyclic diolefin as a raw material. An alicyclic diolefin is a hydrocarbon compound having two or more ethylenically unsaturated bonds and a non-aromatic ring structure in its molecular structure. Specific examples of the alicyclic diolefin include cyclopentadiene polymers such as cyclopentadiene and dicyclopentadiene, methylcyclopentadiene and methylcyclopentadiene polymers.

The content of the alicyclic diolefin monomer units in the hydrocarbon resin is preferably 0 to 10% by mass, more preferably 0 to 7% by mass, still more preferably 0 to 5% by mass, and particularly preferably is 0 to 3% by mass. When the content is within the above range, the rolling resistance and wear resistance of the obtained crosslinked rubber can be further enhanced.

Further, the hydrocarbon resin used in the present invention includes, as aliphatic monomer units, the above-mentioned 1,3-pentadiene-derived monomer units, alicyclic monoolefin monomer units having 4 to 6 carbon atoms, carbon In addition to the acyclic monoolefin monomer units of numbers 4 to 8 and the alicyclic diolefin monomer units, other aliphatic monomer units are contained within the range in which the effects of the present invention can be obtained. good too.

Other aliphatic monomers used to form such other aliphatic monomer units are compounds other than the above-described aliphatic monomers, and are adduct copolymers with 1,3-pentadiene and the like. There is no particular limitation as long as it is a compound having addition polymerizability that can be polymerized. Examples of the other aliphatic monomers include 4 carbon atoms other than 1,3-pentadiene such as 1,3-butadiene, 1,2-butadiene, isoprene, 1,3-hexadiene, and 1,4-pentadiene. alicyclic monoolefins having 7 or more carbon atoms such as cycloheptene; acyclic monoolefins having 3 or less carbon atoms or 9 or more carbon atoms such as ethylene, propylene, nonene;

The content of the other monomer units in the hydrocarbon resin is not particularly limited as long as it is within the range in which the effects of the present invention can be obtained, but is preferably 0 to 30% by mass, more preferably 0 to 25% by mass, more preferably 0 to 20% by mass.

The content of the aliphatic monomer unit in the hydrocarbon resin is preferably 50 to 99.9% by mass, more preferably 55 to 95% by mass, still more preferably 57 to 92% by mass, particularly preferably 60 to 90% by mass. By setting the content of the aliphatic monomer unit within the above range, the rolling resistance and abrasion resistance of the obtained crosslinked rubber can be further enhanced.

(aromatic monomer unit)
The aromatic monomer for forming the aromatic monomer unit may be any one having an aromatic ring and capable of being copolymerized with an aliphatic monomer, such as styrene, α-methyl Styrene compounds such as styrene and vinyltoluene; indene, methylindene, ethylindene, propylindene, butylindene, t-butylindene, sec-butylindene, n-pentylindene, 2-methyl-butylindene, 3-methyl-butyl Indene compounds such as indene, n-hexylindene, 2-methyl-pentylindene, 3-methyl-pentylindene, 4-methyl-pentylindene; 1-vinylnaphthalene, 2-vinylnaphthalene, allylnaphthalene, butenylnaphthalene naphthalene compounds; fluorene compounds such as 2,7-divinylfluorene, 2-vinylfluorene, allylfluorene and butenylfluorene; biphenyl compounds such as 4-vinylbiphenyl and 4-vinyl-p-terphenyl; 9-vinylanthracene, 2 -anthracene compounds such as vinylanthracene, 9,10-divinylanthracene, allylanthracene, butenylanthracene; phenanthrene compounds such as 9-vinylphenanthrene and 3-vinylphenanthrene; benzos such as 5-vinylbenzothiophene and 2-vinylbenzothiophene thiophene compounds; etc. Among these, styrene compounds and indene compounds are preferred, and styrene and indene are more preferred. These aromatic monomers may be used singly or in combination of two or more. Also, a mixture containing these aromatic monomers may be added to the polymerization reaction system during the production of the hydrocarbon resin. At this time, the aromatic monomer contained in the mixture is used as a component of the monomer units constituting the hydrocarbon resin. The addition-polymerizable components other than the aromatic monomer contained in the mixture may also be used as constituent components of the monomer units of the hydrocarbon resin, and the non-addition-polymerizable component may be used as a solvent during polymerization. . As a mixture containing such an aromatic monomer, for example, a C9 fraction containing a styrene compound, an indene compound, etc. as the aromatic monomer can be preferably used.

Further, when the hydrocarbon resin contains, as the aromatic monomer unit, a monomer unit having a structure in which two or more cyclic structures are bonded, the rolling resistance and wear resistance of the crosslinked rubber obtained are further enhanced. be able to.

As a monomer constituting a monomer unit having a structure in which two or more cyclic structures are bonded, usually one or more aliphatic carbon-carbon unsaturated bonds in the molecular structure and two or more cyclic structures is preferably used. Here, the structure in which two or more cyclic structures are bonded may include one or more aromatic rings among the two or more cyclic structures. It may contain rings and non-aromatic ring structures. The content of monomer units having a structure in which two or more cyclic structures are bonded in the hydrocarbon resin is preferably 0.1 to 50% by mass, more preferably 5 to 45% by mass, still more preferably 8 to 43% by mass, particularly preferably 10 to 40% by mass. By setting the content of the monomer unit having a structure in which two or more cyclic structures are bonded within the above range, the rolling resistance and wear resistance of the obtained crosslinked rubber can be further enhanced.

As the aliphatic carbon-carbon unsaturated bond, any one having radical polymerizability can be used, and a vinyl group can be preferably used. When the monomer having a structure in which two or more cyclic structures are bonded is indene, the aliphatic carbon-carbon unsaturated bond is included as part of the five-membered ring of indene.

As the monomer having a structure in which two or more cyclic structures are bonded, naphthalene compounds, fluorene compounds, biphenyl compounds, anthracene compounds, phenanthrene compounds, indene compounds and benzothiophene compounds are preferred, indene compounds are more preferred, and indene is preferred. More preferred.

The aromatic monomer unit content in the hydrocarbon resin is preferably 0.1 to 50% by mass, more preferably 5 to 45% by mass, still more preferably 8 to 43% by mass, particularly preferably 10% by mass. ~40% by mass. By setting the content of the aromatic monomer unit within the above range, the rolling resistance and abrasion resistance of the obtained crosslinked rubber can be further enhanced.

The hydrocarbon resin in the present invention contains 10 to 60% by mass of 1,3-pentadiene monomer units, 1 to 30% by mass of alicyclic monoolefin monomer units having 4 to 6 carbon atoms, and 4 to 8 carbon atoms. It contains 1 to 50% by mass of acyclic monoolefin monomer units, 0 to 10% by mass of alicyclic diolefin monomer units, and 0.1 to 50% by mass of the aromatic monomer units. preferable. By containing such a hydrocarbon resin, the rolling resistance and wear resistance of the obtained crosslinked rubber can be further enhanced.
The content ratio of the monomer unit is the same in the hydrogenated hydrocarbon resin, and the preferred range of the content ratio is also the same as in the hydrocarbon resin.

(Method for producing hydrocarbon resin before hydrogenation)
The method for producing the hydrocarbon resin is not particularly limited as long as the polymerizable component (monomer mixture A) having the above-described aliphatic monomer and aromatic monomer is preferably subjected to addition polymerization. For example, a hydrocarbon resin can be obtained by addition polymerization using a Friedel-Crafts-type cationic polymerization catalyst.

Methods preferably used for producing the hydrocarbon resin include, for example, the following aluminum halide (A), a halogenated hydrocarbon having a halogen atom bonded to a tertiary carbon atom (B1) and a carbon- 1,3-pentadiene 10 is combined with a halogenated hydrocarbon (B) selected from the group consisting of halogenated hydrocarbons (B2) in which a halogen atom is bonded to a carbon atom adjacent to a carbon unsaturated bond to form a polymerization catalyst. to 60% by mass, 10 to 30% by mass of alicyclic monoolefins having 4 to 6 carbon atoms, 1 to 50% by mass of acyclic monoolefins having 4 to 8 carbon atoms, 0 to 10% by mass of alicyclic diolefins, and a method comprising a polymerization step of polymerizing a monomer mixture A containing 0.1 to 50% by mass of an aromatic monomer.

Specific examples of the aluminum halide (A) include aluminum chloride (AlCl ₃ ) and aluminum bromide (AlBr ₃ ). Among them, aluminum chloride is preferably used from the viewpoint of versatility.

The amount of aluminum halide (A) used is not particularly limited, but is preferably 0.05 to 10 parts by mass, more preferably 0.1 to 5 parts by mass, based on 100 parts by mass of the polymerizable component (monomer mixture A). part by mass.

Further, in the polymerization, by using the halogenated hydrocarbon (B) together with the halogenated aluminum (A), the activity of the polymerization catalyst becomes extremely good.

Specific examples of the halogenated hydrocarbon (B1) having a halogen atom bonded to a tertiary carbon atom as the halogenated hydrocarbon (B) include t-butyl chloride, t-butyl bromide, and 2-chloro-2-methylbutane. , triphenylmethyl chloride, and the like. Among these, t-butyl chloride is particularly preferably used because of its excellent balance between activity and ease of handling.

As the halogenated hydrocarbon (B), the unsaturated bond in the halogenated hydrocarbon (B2) in which a halogen atom is bonded to the carbon atom adjacent to the carbon-carbon unsaturated bond includes a carbon-carbon double bond and a carbon- Carbon triple bonds are included, including carbon-carbon conjugated double bonds in aromatic rings and the like. Specific examples of such compounds include benzyl chloride, benzyl bromide, (1-chloroethyl)benzene, allyl chloride, 3-chloro-1-propyne, 3-chloro-1-butene, 3-chloro-1-butyne, and siliceous chloride. Among these, benzyl chloride is preferably used because of its excellent balance between activity and ease of handling.

The halogenated hydrocarbon (B) may be used alone or in combination of two or more.

The amount of the halogenated hydrocarbon (B) to be used is preferably 0.05-50, more preferably 0.1-10 in molar ratio to the aluminum halide (A).

In carrying out the polymerization reaction, the order of adding the respective components of the monomer mixture and the polymerization catalyst to the polymerization reactor is not particularly limited, and may be added in any order. From the viewpoint of further increasing the rolling resistance and abrasion resistance of the resulting crosslinked rubber, the monomer mixture and a part of the components of the polymerization catalyst are added to the polymerization reactor to initiate the polymerization reaction, and then the polymerization catalyst is added. is preferably added to the polymerization reactor.

Specifically, in the production of the hydrocarbon resin, first, it is preferable to previously mix the aluminum halide (A) and the alicyclic monoolefin. By contacting the aluminum halide (A) and the alicyclic monoolefin in advance, the formation of gel can be prevented, and the rolling resistance and abrasion resistance of the obtained crosslinked rubber can be further enhanced.

The amount of the alicyclic monoolefin mixed with the aluminum halide (A) is preferably at least 5 times the amount of the aluminum halide (A) (mass ratio). If the amount of the alicyclic monoolefin is too small, the effect of preventing gel formation may be reduced. The mass ratio of the alicyclic monoolefin to the aluminum halide (A) is preferably 5:1 to 120:1, more preferably 5:1 to 120:1, in terms of the mass ratio of "alicyclic monoolefin: aluminum halide (A)". 10:1 to 100:1, more preferably 15:1 to 80:1. If the alicyclic monoolefin is used in a larger amount than this ratio, the catalytic activity may be lowered and the polymerization may not proceed sufficiently.

When the aluminum halide (A) and the alicyclic monoolefin are mixed in advance, the order in which they are added is not particularly limited, and the aluminum halide (A) may be added to the alicyclic monoolefin, Conversely, an alicyclic monoolefin may be introduced into the aluminum halide (A). Suitable diluents may also be used as mixing is generally exothermic. As a diluent, a solvent to be described later can be used.

After preparing the mixture M of the aluminum halide (A) and the alicyclic monoolefin as described above, the mixture a containing at least 1,3-pentadiene and the acyclic monoolefin and the mixture M are mixed. preferably. The mixture a may contain alicyclic diolefins and/or aromatic monomers.

The method for preparing the mixture a is not particularly limited, and the target mixture a may be obtained by mixing pure compounds respectively, or, for example, the target monomers derived from naphtha cracked product fractions etc. A mixture may be used to obtain the desired mixture a. For example, in order to add 1,3-pentadiene or the like to the mixture a, the C5 fraction after extraction of isoprene and cyclopentadiene (including their multimers) can be preferably used.

It is preferable to further mix the halogenated hydrocarbon (B) with the mixture a and the mixture M. The order in which these three are introduced is not particularly limited.

From the viewpoint of better control of the polymerization reaction, it is preferable to add a solvent to the polymerization reaction system and 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 suitable. Examples of saturated aliphatic hydrocarbons used as solvents 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. chain saturated aliphatic hydrocarbons of 5 to 10; cyclic saturated aliphatic hydrocarbons of 5 to 10 carbon atoms such as cyclopentane, cyclohexane, cycloheptane and cyclooctane; Examples of aromatic hydrocarbons used as solvents include aromatic hydrocarbons having 6 to 10 carbon atoms such as benzene, toluene and xylene. One solvent may be used alone, or two or more solvents may be used as a mixed solvent.

The amount of solvent used is not particularly limited, but is preferably 10 to 1,000 parts by mass, more preferably 50 to 500 parts by mass, per 100 parts by mass of the polymerizable component (monomer mixture A). 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 a C5 fraction, is added to the polymerization reaction system, and the addition polymerizable component is a monomer. It can also be used as a component of the polymer mixture and the non-addition polymerizable component can be used as a solvent.

The polymerization temperature for the polymerization reaction is not particularly limited, but is preferably -20°C to 100°C, more preferably 10°C to 70°C. If the polymerization temperature is too low, the polymerization activity may decrease, resulting in poor productivity. If the polymerization temperature is too high, the obtained crosslinked rubber may have poor rolling resistance and wear resistance. The pressure during the polymerization reaction may be atmospheric pressure or increased pressure. The polymerization reaction time can be selected as appropriate, but is usually 10 minutes to 12 hours, preferably 30 minutes to 6 hours.

The polymerization reaction can be terminated by adding a polymerization terminator such as methanol, an aqueous sodium hydroxide solution, an aqueous ammonia solution, or the like to the polymerization reaction system when a desired polymerization conversion rate is obtained.

The method for producing a hydrocarbon resin may include at least the polymerization step, but may include other steps as necessary.

As another step, for example, after the polymerization step, a polymerization terminator is added in the polymerization step to remove the catalyst residue insoluble in the solvent, which is generated when the polymerization catalyst is deactivated, by filtration or the like. After stopping the polymerization reaction in the polymerization step, the unreacted monomers and solvent are removed, and the low-molecular-weight oligomer component is removed by steam distillation or the like, followed by cooling to obtain a solid hydrocarbon resin. a recovery step for obtaining

In addition, as another step, after the catalyst residue removal step and before the recovery step, the catalyst residue-removed mixture after removing the solvent-insoluble catalyst residue is brought into contact with the adsorbent to obtain an adsorbent-treated mixture. A processing step may be provided. By providing the contact treatment step, the rolling resistance and wear resistance of the obtained crosslinked rubber can be further enhanced.

The above-mentioned other steps may be performed after the hydrogenation step in the method for producing a hydrogenated hydrocarbon resin, which will be described later.

The adsorbent used in the contact treatment step is not particularly limited, and may be a chemical adsorbent or a physical adsorbent.

Examples of the chemical adsorbent include zinc-based adsorbents such as basic zinc carbonate, zinc oxide, zinc sulfate, zinc laurate, zinc stearate, and zinc myristate; Manganese-based adsorbents such as manganese dioxide; Cobalt-based adsorbents such as cobalt chloride; Copper-based adsorbents such as copper chloride and copper oxide;

Examples of the physical adsorbent include zeolite-based adsorbents, which are collectively referred to as hydrous aluminosilicate minerals such as sodium aluminum silicate, silicon dioxide, magnesium oxide, silica gel, silica-alumina, aluminum silicate, activated alumina, and acid clay. , activated clay, dawsonite compounds, hydrotalcite compounds, and the like.

Adsorbents may be used singly or in combination of two or more. Further, when two or more adsorbents are used in combination, two or more chemical adsorbents may be used in combination, two or more physical adsorbents may be used in combination, or one or more chemical adsorbents may be used in combination. The agent may be used in combination with one or more physical adsorbents, for example, the physical adsorbent may carry a chemical adsorbent. Among these adsorbents, it is preferable to use a chemical adsorbent, more preferably a zinc-based adsorbent, and a basic Particular preference is given to using zinc carbonate.

In the contact treatment step, the method of contacting the catalyst residue-removed mixture with the adsorbent is not particularly limited. For example, a batch treatment method in which the mixture for removing the catalyst residue and the adsorbent are allowed to coexist in an appropriately selected container, and are stirred as necessary to bring them into contact with each other, or a packed tower is filled with the adsorbent in advance, and this a continuous treatment method in which the catalyst residue-removed mixture is brought into contact with the

When the catalyst residue-removed mixture and the adsorbent are brought into contact with each other by a batch treatment method, the amount of the adsorbent used is not particularly limited, but is usually 0.00 per 100 parts by mass of the hydrocarbon resin contained in the catalyst residue-removed mixture. 01 to 5.0 parts by mass, preferably 0.03 to 3.0 parts by mass, more preferably 0.05 to 2.0 parts by mass.

The temperature at which the catalyst residue-removing mixture and the adsorbent are brought into contact is not particularly limited, but is usually 10 to 70°C. Also, the treatment time is not particularly limited, but is usually 0.1 to 2 hours.

When the catalyst residue-removed mixture and the adsorbent are brought into contact with each other in a batch process, the adsorbent can be removed from the catalyst residue-removed mixture by filtration or the like, if necessary. Further, when there is no problem in using the hydrocarbon resin and the hydrogenated hydrocarbon resin even if the adsorbent remains, the catalyst residue-removed mixture may be subjected to the next step without removing the adsorbent.

<Hydrocarbon resin hydride>
The hydrocarbon resin hydride used in the present invention can be obtained by hydrogenating the hydrocarbon resin described above.

The hydrocarbon resin hydride used in the present invention may have a hydrogenation rate in the range of 0.1 to 80%, preferably in the range of 10 to 60%, more preferably 20 to 50%. Within range. By setting the hydrogenation rate within the above range, the rolling resistance and wear resistance of the obtained crosslinked rubber can be further enhanced. The degree of hydrogenation means the ratio of hydrogenated ones among all the non-aromatic carbon-carbon double bonds of the hydrocarbon resin before hydrogenation.

In addition, as the carbon-carbon double bond in the hydrocarbon resin, in addition to non-aromatic carbon-carbon double bonds (mainly carbon-carbon double bonds in the main chain), aromatic carbon-carbon double bonds Although heavy bonds (carbon-carbon double bonds within the aromatic ring) are present, the aromatic carbon-carbon double bonds are preferably as unhydrogenated as possible and all aromatic carbon-carbon double bonds Among them, the hydrogenated ratio is preferably 10% or less, more preferably 7% or less, and still more preferably 0%.

The degree of hydrogenation can be determined from the difference in non-aromatic carbon-carbon double bonds possessed by the hydrocarbon resin before hydrogenation and the hydrogenated hydrocarbon resin after hydrogenation. Here, the non-aromatic carbon-carbon double bond possessed by each resin can be determined by ¹ H-NMR spectroscopy. ¹ H-NMR spectrum measurement can be performed using deuterated chloroform as a solvent and using JMN-AL series AL400 (manufactured by JEOL) as an NMR spectrometer.

Further, the weight average molecular weight (Mw) of the hydrogenated hydrocarbon resin after hydrogenation may be in the range of 700 to 6,000, preferably in the range of 900 to 4,500, more preferably 1,000. ~4,000. By setting the weight average molecular weight (Mw) within the above range, the processability of the obtained rubber composition and the balance of tensile strength, elongation, wet grip properties, rolling resistance and abrasion resistance of the obtained crosslinked rubber product can be further enhanced.

The number average molecular weight (Mn) of the hydrogenated hydrocarbon resin after hydrogenation is preferably in the range of 400 to 3,000, more preferably in the range of 450 to 2,500, still more preferably in the range of 500 to 2,000. is within. By setting the number average molecular weight (Mn) within the above range, the processability of the obtained rubber composition and the balance of tensile strength, elongation, wet grip properties, rolling resistance, and abrasion resistance of the crosslinked rubber obtained. can be further enhanced.

The Z-average molecular weight (Mz) of the hydrogenated hydrocarbon resin after hydrogenation is preferably in the range of 1,500 to 20,000, more preferably in the range of 1,800 to 10,000, still more preferably 2, It is in the range of 000 to 8,000. By setting the Z-average molecular weight (Mz) within the above range, the processability of the obtained rubber composition and the balance of tensile strength, elongation, wet grip properties, rolling resistance and abrasion resistance of the crosslinked rubber obtained are achieved. can be further enhanced.

In the present invention, the weight-average molecular weight (Mw), number-average molecular weight (Mn), and Z-average molecular weight (Mz) of the hydrogenated hydrocarbon resin are obtained as polystyrene-equivalent values measured by high-performance liquid chromatography. do.

In addition, the ratio (Mw/Mn) of the weight average molecular weight to the number average molecular weight of the hydrogenated hydrocarbon resin is preferably in the range of 1.0 to 4.0, more preferably in the range of 1.2 to 3.5. within, more preferably within the range of 1.4 to 3.0. When the above ratio is within the above range, the obtained crosslinked rubber can have higher rolling resistance and wear resistance.

The ratio of the Z-average molecular weight to the weight-average molecular weight of the hydrogenated hydrocarbon resin (Mz/Mw) is preferably within the range of 1.0 to 4.0, more preferably within the range of 1.2 to 3.5 , more preferably in the range of 1.4 to 3.0. When the above ratio is within the above range, the obtained crosslinked rubber can have higher rolling resistance and wear resistance.

The softening point of the hydrogenated hydrocarbon resin may be in the range of 80 to 150°C, preferably in the range of 85 to 145°C, and more preferably in the range of 90 to 140°C. By setting the softening point within the above range, the rolling resistance and abrasion resistance of the obtained crosslinked rubber can be further enhanced.

The softening point in the present invention can be measured according to JIS K 2207 for hydrogenated hydrocarbon resins.

As a method for producing a hydrogenated hydrocarbon resin, for example, a method including a hydrogenation step of hydrogenating a hydrocarbon resin can be used.

In the hydrogenation step, hydrogenation of the hydrocarbon resin can be carried out by contacting the hydrocarbon resin with hydrogen in the presence of a hydrogenation catalyst.

As the hydrogenation catalyst to be used, JP-B-58-43412, JP-A-60-26024, JP-A-64-24826, JP-A-1-138257, JP-A-7-41550, etc. Those described can be used, both homogeneous and heterogeneous catalysts.

Examples of homogeneous catalysts include combinations of cobalt acetate/triethylaluminum, nickel acetylacetonate/triisobutylaluminum, titanocene dichloride/n-butyllithium, zirconocene dichloride/sec-butyllithium, tetrabutoxytitanate/dimethylmagnesium, and the like. catalyst system consisting of a combination of a transition metal compound and an alkali metal compound; noble metal complex catalysts such as dichlorobis(triphenylphosphine)palladium, chlorohydridocarbonyltris(triphenylphosphine)ruthenium, chlorotris(triphenylphosphine)rhodium; .

Examples of heterogeneous catalysts include those in which hydrogenation catalyst metals such as Ni and Pd are supported on a carrier. Examples of carriers include silica, alumina, silica-alumina, diatomaceous earth, and the like. Among them, a Ni catalyst supported on silica is preferable.

The hydrogenation reaction may be carried out directly on the hydrocarbon resin, or the hydrocarbon resin may be dissolved in an organic solvent and carried out in the organic solvent. From the viewpoint of ease of operation, it is preferable to carry out directly on the hydrocarbon resin. The organic solvent used for dissolving the hydrocarbon resin is not particularly limited as long as it is inert to the catalyst, but hydrocarbon solvents are usually used because they are excellent in the solubility of the hydrogenated product to be produced. Used.

Examples of hydrocarbon solvents include aromatic hydrocarbons such as benzene and toluene; aliphatic hydrocarbons such as n-pentane and hexane; alicyclic hydrocarbons such as cyclohexane and decalin; Among these, cyclic aromatic hydrocarbons and alicyclic hydrocarbons are preferred. These organic solvents can be used singly or in combination of two or more. As the organic solvent, the solvent used for the polymerization of the hydrocarbon resin may be used.

The method of contacting the hydrocarbon resin with hydrogen in the presence of a hydrogenation catalyst is not particularly limited. For example, a batch processing method in which a hydrocarbon resin and a hydrogenation catalyst are coexisted in an appropriately selected container, stirred as necessary, and brought into contact with hydrogen, or a hydrogenation catalyst is filled in a packed tower in advance. A continuous treatment method can be mentioned in which the hydrocarbon resin is brought into contact with hydrogen while flowing through it.

A hydrogenation reaction can be performed according to a conventional method. By appropriately adjusting reaction conditions such as the type of hydrogenation catalyst and reaction temperature, the hydrogenation ratio of the hydrocarbon resin can be adjusted.

When a homogeneous catalyst is used as the hydrogenation catalyst, the hydrogenation rate of the hydrocarbon resin can be increased. As the homogeneous catalyst, a ruthenium homogeneous catalyst is suitable. The reaction temperature is preferably 100-200°C, more preferably 130-195°C. Further, when a heterogeneous catalyst is used as the hydrogenation catalyst, the hydrogenation rate of the hydrocarbon resin can be suppressed. As the heterogeneous catalyst, a nickel heterogeneous catalyst is suitable. The reaction temperature is preferably 150-300°C, more preferably 180-260°C.

The hydrogen pressure in the hydrogenation reaction is usually 0.01 to 10 MPa, preferably 0.05 to 6 MPa, more preferably 0.1 to 5 MPa in terms of absolute pressure.

In addition, the lower limit of the amount of hydrogen used is preferably 1 time or more, more preferably 1.2 times or more, and further 1.8 times or more of the amount of hydrogen theoretically required to obtain a resin with a desired hydrogenation rate. Preferably, the upper limit of the amount of hydrogen to be used is preferably 20 times or less, more preferably 10 times or less, and even more preferably 5 times or less, of the amount of hydrogen theoretically required to obtain a resin having a desired hydrogenation rate. Four times or less is particularly preferable. By setting the amount of hydrogen to be used within the above range, the rolling resistance and wear resistance of the obtained crosslinked rubber can be further enhanced.

After completion of the hydrogenation reaction, the hydrogenation catalyst is removed from the reaction solution by centrifugation, filtration, or the like, if necessary. The centrifugation method and the filtration method are not particularly limited as long as the conditions are such that the used catalyst can be removed. Removal by filtration is preferred because it is simple and efficient. When filtering, pressure filtration or suction filtration may be used, and from the viewpoint of efficiency, it is preferable to use a filter aid such as diatomaceous earth or perlite. Moreover, if necessary, a catalyst deactivator such as water or alcohol can be used, or an adsorbent such as activated clay or alumina can be added.

<Diene rubber>
The rubber composition of the present invention contains a diene rubber in addition to the hydrogenated hydrocarbon resin described above. The diene rubber is not particularly limited as long as it can be blended with the hydrogenated hydrocarbon resin. Examples of such diene-based rubbers include diene-based rubbers described in JP-A-2015-189873. Specifically, natural rubber (NB), isoprene rubber (IR), butadiene rubber ( BR), styrene-butadiene copolymer rubber (SBR), ethylene-propylene-diene terpolymer (EPDM), etc. Among them, styrene-butadiene copolymer rubber, natural rubber, etc. are preferable. . By using the diene rubber described above, the rolling resistance and wear resistance of the obtained crosslinked rubber can be further enhanced. The diene rubber may be used singly or in combination of two or more.

In addition, the diene rubber in the present invention is not particularly limited in its molecular weight or microstructure, and may be terminally modified with an amine, amide, silyl, alkoxysilyl, carboxyl, hydroxyl group, or the like, or may be epoxidized. . Further, the diene 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 rubber and the hydrogenated hydrocarbon resin is 1 to 30 parts by mass of the hydrogenated hydrocarbon resin per 100 parts by mass of the diene rubber. It is preferable to mix 5 to 20 parts by mass. By setting the mixing ratio of the diene rubber to the hydrogenated hydrocarbon resin within the above range, the rolling resistance and wear resistance of the obtained crosslinked rubber can be further enhanced.

Also, the amount of the hydrogenated hydrocarbon resin is preferably within the range of 1 to 30% by mass, more preferably within the range of 3 to 25% by mass, of the amount of silica to be described later.

<Silica>
The rubber composition of the present invention contains silica in addition to the above hydrogenated hydrocarbon resin and diene rubber. Examples of silica include dry white carbon, wet white carbon, colloidal silica, and precipitated silica. Among these, wet process white carbon containing hydrous silicic acid as a main component is preferable. A carbon-silica dual phase filler in which silica is supported on the surface of carbon black may also 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 100-400 m ² /g, more preferably 150-350 m ² /g. Further, the pH of silica is preferably pH 5-10.

The amount of silica compounded in the rubber composition of the present invention may be 80 to 200 parts by mass, preferably 85 to 150 parts by mass, and more preferably 90 to 120 parts by mass with respect to 100 parts by mass of the diene rubber. be. By setting the amount of silica to be blended within the above range, the rolling resistance and abrasion resistance of the obtained crosslinked rubber can be further enhanced.

Moreover, the rubber composition of the present invention preferably contains a silane coupling agent together with silica. Silane coupling agents include, for example, vinyltriethoxysilane, β-(3,4-epoxycyclohexyl)ethyltrimethoxysilane, N-(β-aminoethyl)-γ-aminopropyltrimethoxysilane, 3-octatio- 1-propyl-triethoxysilane, bis(3-(triethoxysilyl)propyl)disulfide, bis(3-(triethoxysilyl)propyl)tetrasulfide, γ-trimethoxysilylpropyldimethylthiocarbamyltetrasulfide, and γ -trimethoxysilylpropylbenzothiazyltetrasulfide and the like. These silane coupling agents can be used alone or in combination of two or more. The amount of the silane coupling agent compounded is preferably 0.1 to 30 parts by mass, more preferably 1 to 15 parts by mass with respect to 100 parts by mass of silica.

The rubber composition of the present invention may consist of only the diene rubber, the hydrogenated hydrocarbon resin, and silica, but may further contain other components. Other components that can be contained in the rubber composition of the present invention include, for example, fillers other than silica, cross-linking agents, cross-linking accelerators, cross-linking activators, antioxidants, antioxidants, activators, process oils, plasticizers, agents, lubricants, tackifiers, etc., and these other compounding agents can be added in necessary amounts.

As fillers other than silica that can be blended in the rubber composition of the present invention, those commonly used in rubber compositions can be used, for example, carbon black, clay, diatomaceous earth, talc, barium sulfate, carbonate Inorganic hollow fillers such as calcium, magnesium carbonate, metal oxides, mica, aluminum hydroxide, various metal powders, wood powders, glass powders, ceramic powders, glass balloons, silica balloons; polystyrene, polyvinylidene fluoride, polyvinylidene fluoride Examples include organic hollow fillers such as polymers.

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.

Moreover, a filler may be used individually by 1 type, or may be used in combination of 2 or more type.

The content of the filler other than silica may be within the range in which the effects of the present invention can be obtained, for example, it can be 120 parts by mass or less per 100 parts by mass of the rubber component.

Examples of cross-linking agents include, but are not limited to, sulfur, halogenated sulfur, organic peroxides, quinone dioximes, organic polyvalent amine compounds, and alkylphenol resins having methylol groups. Among these, sulfur is preferably used. The amount of the cross-linking agent 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 using sulfur or a sulfur-containing compound as a cross-linking agent, it is preferable to use a cross-linking accelerator and a cross-linking activator together. Examples of cross-linking accelerators include sulfenamide-based cross-linking accelerators; guanidine-based cross-linking accelerators; thiourea-based cross-linking accelerators; thiazole-based cross-linking accelerators; thiuram-based cross-linking accelerators; cross-linking accelerator; and the like. Among these, those containing a sulfenamide cross-linking accelerator are preferred. These cross-linking accelerators may be used alone or in combination of two or more. The amount of the cross-linking accelerator compounded 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. Department.

Cross-linking activators include, for example, 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 amount of the cross-linking activator is preferably 0.05 to 20 parts by mass, particularly preferably 0.5 to 15 parts by mass, per 100 parts by mass of the rubber component in the rubber composition.

In addition, anti-aging agents such as phenol-based stabilizers, phosphorus-based stabilizers and sulfur-based stabilizers may be added to the rubber composition of the present invention, if desired. The amount of the anti-aging agent to be added may be appropriately determined depending on the type of anti-aging agent.

Moreover, you may add antioxidant to the rubber composition of this invention as needed. Examples of antioxidants include, but are not limited to, pentaerythritol tetrakis[3-(3,5-di-t-butyl-4-hydroxyphenyl)propionate], octadecyl-3-(3,5-di-t -butyl-4-hydroxyphenyl)propionate, 2,6-di-t-butyl-p-cresol, hindered phenolic compounds such as di-t-butyl-4-methylphenol; thiodicarboxylate esters; phosphites such as tris(nonylphenyl)phosphite; and the like. Antioxidants may be used singly or in combination of two or more. Although the content of the antioxidant is not particularly limited, it is preferably 10 parts by mass or less, more preferably 0.05 to 5 parts by mass, based on 100 parts by mass of the rubber component in the rubber composition.

Further, the rubber composition of the present invention may contain a resin other than the diene rubber and the hydrocarbon resin hydrogen compound described above. By blending the resin, the rubber composition can be imparted with tackiness and the dispersibility of the filler in the rubber composition can be enhanced. As a result, an improvement in rolling resistance and wear resistance of the resulting crosslinked rubber can be expected. In addition, as an effect similar to that of the plasticizer, it is also possible to improve the processability of the rubber composition. Examples of resins include C5 petroleum resins, C5/C9 petroleum resins, C9 petroleum resins, dicyclopentadiene resins, terpene resins, terpene phenol resins, aromatic modified terpene resins, alkylphenol-acetylene resins, and rosin resins. resins, rosin ester resins, indene-based resins, C9-based resins containing indene, α-methylstyrene/indene copolymer resins, coumarone-indene resins, farnesene-based resins, polylimonene resins, and the like. These resins may be modified or hydrogenated. These resins may be used alone or in combination of two or more. The amount of the resin compounded 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 the rubber composition of the present invention, each component may be kneaded according to a conventional method. After kneading with resin hydride, heat-unstable components such as a cross-linking agent and a cross-linking accelerator can be kneaded into the kneaded product to obtain the target rubber composition. The kneading temperature for kneading the components excluding the thermally unstable components, the diene rubber, and the hydrogenated hydrocarbon resin is preferably 80 to 200°C, more preferably 120 to 180°C. The time is preferably 30 seconds to 30 minutes. The kneaded product and the heat-labile component are kneaded after cooling to preferably 100° C. or lower, more preferably 80° C. or lower.

By using the rubber composition of the present invention, a cross-linked rubber having excellent rolling resistance and wear resistance can be obtained. Taking advantage of such properties, the rubber composition of the present invention is preferably used as a material for various tire parts such as the tread (cap tread, base tread), carcass, sidewall, and bead portion 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 tire part such as the tread, carcass, sidewall, and bead portion. It can be used particularly preferably, and it is particularly preferable to use it for a cap tread.

<Rubber cross-linked product>
The rubber cross-linked product of the present invention is obtained by cross-linking the rubber composition of the present invention described above.
The rubber cross-linked product of the present invention can be obtained by molding the rubber composition of the present invention into a desired shape using a molding machine such as an extruder, an injection molding machine, a compressor, a roll, etc., and then heating. It can be produced by performing a cross-linking reaction with and fixing the shape as a rubber cross-linked product. In this case, the cross-linking may be performed after pre-molding, or the cross-linking may be performed at the same time as the molding. The molding temperature is usually 10-200°C, preferably 25-120°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 cross-linked rubber product, even if the surface is cross-linked, the inside may not be sufficiently cross-linked, so secondary cross-linking may be performed by further heating.

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

The cross-linked rubber product of the present invention thus obtained is obtained using the above-described rubber composition of the present invention, and therefore has excellent rolling resistance and abrasion resistance.

Taking advantage of its excellent rolling resistance and wear resistance, the cross-linked rubber of the present invention is used, for example, as a material for tire parts such as tread (cap tread, base tread), carcass, sidewall, bead portion, etc. In particular, in various tires such as all-season tires, high-performance tires, and studless tires, it can be suitably used for each tire portion such as the tread, carcass, sidewall, and bead portion. It can be particularly preferably used for the tread of the above, and it is particularly preferable to use it for the cap tread.

Next, the pneumatic tire of the present invention will be explained. A pneumatic tire according to the present invention is characterized by using the rubber composition described above in a tread.

The tread uses the above-mentioned rubber composition, that is, is formed using the above-mentioned rubber composition, and usually the rubber composition of the present invention is crosslinked. It includes things.

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

The tread formed using the rubber composition may be a part of the tread or the entire tread, but preferably includes at least a cap tread.

Moreover, as the method for manufacturing the pneumatic tire of the present invention, any method can be used as long as it can manufacture a pneumatic tire having a tread formed using the above composition, and a known method for manufacturing a pneumatic tire can be used. can.

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

[Hydrogenation rate (%)]
By performing ¹ H-NMR spectrum measurement on the hydrocarbon resin before hydrogenation and the hydrocarbon resin hydride after hydrogenation, the amount of non-aromatic carbon-carbon double bonds was determined, and Hydrogenation rate (%) was determined based on the difference in the amount of non-aromatic carbon-carbon double bonds. Note that ^{the 1} H-NMR spectrum was measured using deuterated chloroform as a solvent and JMN-AL series AL400 (manufactured by JEOL) as an NMR spectrometer.

[Number Average Molecular Weight, Weight Average Molecular Weight, Z Average Molecular Weight, and Molecular Weight Distribution]
Hydrocarbon resin hydride as a sample is analyzed by gel permeation chromatography to obtain the number average molecular weight (Mn), weight average molecular weight (Mw), and Z average molecular weight (Mz) in terms of standard polystyrene. The distribution is shown as the ratio of Mw/Mn and the ratio of Mz/Mw. In addition, gel permeation chromatography analysis uses "HLC-8320GPC" manufactured by Tosoh Corporation as a measuring device, and the column is made by connecting three "TSKgel SuperMultiporeHZ" manufactured by Tosoh Corporation, and tetrahydrofuran is used as a solvent. , 40° C. and a flow rate of 1.0 mL/min.

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

[Mooney viscosity (ML1+4)]
A sample rubber composition was measured under the following conditions according to JIS K 6300-1:2001. This characteristic is indicated by an index with 100 as a reference sample (Comparative Example 1 described later).
・Test temperature: 100°C
・Type of rotor: L type ・Testing machine used: Shimadzu Mooney Viscometer SMV-300J manufactured by Shimadzu Corporation

[Tensile strength (MPa) and elongation (%)]
A test piece of a rubber crosslinked product as a sample was measured for tensile strength (tensile stress (MPa)) and elongation (elongation (%)) according to JIS K 6251:2010 under the following conditions. These characteristics are indicated by an index with 100 as a reference sample (Comparative Example 1 described later).
・Method of preparing test piece: After making a sheet by press cross-linking, punching ・Shape of test piece: Dumbbell-shaped No. 3 shape ・Direction of collecting test piece: parallel to the grain ・Number of test pieces: 3
・Measurement temperature: 23°C
・Test speed: 500mm/min
・ Test machine used: TENSOMETER 10k manufactured by ALPHA TECHNOLOGIES
・Tester capacity: load cell type 1kN

[Loss tangent tan δ]
A test piece of a cross-linked rubber product as a sample was measured for loss tangent tan δ at 0° C. and 60° C. under the following measurement conditions under dynamic strain of 0.5% and 10 Hz in accordance with JIS K 7244-4. . This characteristic is indicated by an index with 100 as a reference sample (Comparative Example 1 described later). 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.
Measurement item: dynamic storage modulus E'
: dynamic loss modulus E”
: Loss tangent tan δ
・Sample preparation method: punching from a sheet ・Specimen shape: length 50 mm x width 2 mm x thickness 2 mm
・Number of test pieces: 1
・Distance between clamps: 20mm

[Abrasion resistance]
A test piece of a sheet-like cross-linked rubber product as a sample was measured using an FPS abrasion tester manufactured by Ueshima Seisakusho Co., Ltd. under a load of 1 kgf and a slip ratio of 15%. This characteristic was calculated as an index with the measured value of the sample of Comparative Example 1 being 100. It can be evaluated that the higher the index, the better the wear resistance.

[Production Example 1]
A polymerization reactor was charged with a mixture of 56.1 parts of cyclopentane and 15.5 parts of cyclopentene, heated to 70° C., and then 0.75 part of aluminum chloride was added (mixture M ₁ ). Subsequently, 46.7 parts of 1,3-pentadiene, 18.4 parts of isobutylene, 0.1 part of diisobutylene, 0.1 part of dicyclopentadiene, 0.2 parts of C4-C6 unsaturated hydrocarbons, C4-C6 saturated hydrocarbons A mixture a ₁ consisting of 7.2 parts of hydrogen and 19.0 parts of styrene was continuously added to the polymerization reactor containing the mixture M ₁ obtained above while maintaining the temperature at 70° C. for 60 minutes. Polymerization was carried out while adding. After that, the polymerization reaction was terminated by adding an aqueous sodium hydroxide solution to the polymerization reactor. Table 1 summarizes the types and amounts of the components in the polymerization reactor during the polymerization reaction. A polymer solution containing the hydrocarbon resin before hydrogenation, unreacted monomers, and the like was obtained by removing the precipitate formed by the polymerization termination by filtration. Then, the polymer solution was placed in a distillation pot and heated under a nitrogen atmosphere to remove the polymerization solvent and unreacted monomers to obtain a hydrocarbon resin before hydrogenation.

Then, the hydrocarbon resin before hydrogenation obtained above was supplied to a shell and tube heat exchange type hydrogenation reactor to hydrogenate the hydrocarbon resin. In the hydrogenation reaction, a nickel silica catalyst (manufactured by Nikki Shokubai Kasei Co., Ltd., N108F) is used as a hydrogenation catalyst. The amount of hydrogen was 1.7 times the amount required to obtain a hydrogenated hydrocarbon resin.

The resulting polymer solution containing the hydrocarbon resin hydride was charged into a still and heated under a nitrogen atmosphere to remove the polymerization solvent and unreacted monomers. Subsequently, while blowing saturated steam at 200° C. or higher, low-molecular-weight oligomer components were distilled off to obtain a hydrocarbon resin hydride of Production Example 1. Hydrogenation rate, number-average molecular weight, weight-average molecular weight, Z-average molecular weight, molecular weight distribution, and softening point of the obtained hydrocarbon resin hydride of Production Example 1 were measured. These measurement results are summarized in Table 1 below.

[Production Examples 2 to 7]
A hydrogenated hydrocarbon resin was 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 hydrogenation conditions were changed as shown in Table 1 below. For the obtained hydrogenated hydrocarbon resins of Production Examples 2 to 7, similarly to the hydrogenated hydrocarbon resin of Production Example 1, the hydrogenation rate, number average molecular weight, weight average molecular weight, Z average molecular weight, molecular weight distribution, and Softening points were measured. These measurement results are summarized in Table 1 below.

[Example 1]
Emulsion-polymerized styrene-butadiene rubber (E-SBR) (trade name “Nipol 1739”, manufactured by Nippon Zeon Co., Ltd., bound styrene content: 40%, vinyl bond content of butadiene unit portion: 13) was oil-extended in a Banbury mixer. .5 mol%, weight average molecular weight: 690,000, molecular weight distribution (Mw/Mn): 3.98, glass transition temperature (Tg): -35°C, 37.5 parts of extender oil per 100 parts of rubber component containing) 96.3 parts (rubber component content: 70 parts, extender oil content: 26.3 parts) and solution polymerized styrene-butadiene rubber (S-SBR) (trade name “Nipol NS 616”, Japan Zeon Co., Ltd., Mooney viscosity (ML1+4, 100° C.): 62) 15 parts and natural rubber (NR) (SIR20) 15 parts were masticated for 30 seconds, followed by silica (Rhodia Co., trade name "Zeosil 1165MP"). ) 60 parts, carbon black (manufactured by Cabot Japan, trade name “N234”) 20 parts, silane coupling agent: bis [3-(triethoxysilyl) propyl] tetrasulfide (manufactured by Tegussa, trade name “Si69”) 9 parts and 10 parts of the hydrocarbon resin hydride obtained in Production Example 1 were added, and after kneading for 90 seconds, 40 parts of silica (manufactured by Rhodia, trade name "Zeosil 1165MP"), 3 parts of zinc oxide, and 2 parts of stearic acid. part, and anti-aging agent: N-phenyl-N'-(1,3-dimethylbutyl)-p-phenylenediamine (manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd., trade name "Nocrac 6C") 2 parts, and further After kneading for 90 seconds, 15 parts of process oil (manufactured by Nippon Oil Co., Ltd., trade name "Aromax T-DAE") was added. After that, the mixture was kneaded at 145 to 155° C. for 60 seconds or more (primary kneading) with a starting temperature of 90° C., and then the kneaded product was discharged from the mixer.

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

Then, with two rolls at 50 ° C., 1.7 parts of sulfur, a cross-linking accelerator: N-cyclohexyl-2-benzothiazolylsulfenamide (CBS trade name "Noccellar CZ-G") , manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.) and 1.7 parts of diphenylguanidine (DPG trade name "Noccellar D" manufactured by Ouchi Shinko Kagaku Kogyo Co., Ltd.) were added and kneaded (cross-linking agent kneading). After that, the sheet-like rubber composition was taken out.

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

(Kneading conditions for primary kneading and secondary kneading)
・Testing machine: Laboplastomill Banbury type mixer B-600 manufactured by Toyo Seiki Seisakusho Co., Ltd.
・Filling rate: 70 to 75 vol%
・Rotor speed: 50 rpm
・Set test start temperature: 90°C

(Kneading conditions for kneading the cross-linking agent)
・Testing machine: Electric heating type high temperature roll machine manufactured by Ikeda Machinery Co., Ltd. ・Roll size: 6φ x 16
・ Front roll rotation speed: 24 rpm
・Front and rear roll rotation ratio: 1:1.22
・Roll temperature: 50±5℃
・Number of turns: 2 times each for left and right ・Rounding width: 0.8 mm between rolls
・Rounding number of times: 5 times

[Examples 2 to 4 and Comparative Examples 1 to 3]
As shown in Table 2 below, the rubber composition was prepared in the same manner as in Example 1 except that the hydrocarbon resin hydrides obtained in Production Examples 2 to 7 were used instead of the hydrocarbon resin hydrides obtained in Production Example 1. got stuff

〔evaluation〕
The rubber compositions obtained in Examples 1 to 4 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 further aged in a constant temperature room at 23° C. overnight. A cross-linked rubber test piece of 150 mm×2 mm thickness was prepared.

For the rubber compositions and crosslinked rubbers obtained in Examples 1 to 4 and Comparative Examples 1 to 3, Mooney viscosity of the rubber composition, tensile strength (MPa) of the crosslinked rubber, elongation (%), loss tangent tan δ , and abrasion resistance were measured. The results are shown in Table 2 below.

As shown in Tables 1 and 2, a hydrocarbon resin hydride obtained by hydrogenating a hydrocarbon resin containing an aliphatic monomer unit and an aromatic monomer unit and having a hydrogenation rate of 0.1 ~80%, a weight average molecular weight (Mw) of 700 to 6,000, and a softening point of 80 to 150°C, a hydrocarbon resin hydride, a diene rubber, and a rubber composition containing silica, The processability was excellent, and the cross-linked rubber obtained was excellent in tensile strength, elongation and wet grip properties, and particularly excellent in rolling resistance and wear resistance (Examples 1 to 4).

On the other hand, the cross-linked rubber made of a rubber composition containing a non-hydrogenated hydrocarbon resin instead of the hydrogenated hydrocarbon resin was inferior in rolling resistance and abrasion resistance (Comparative Examples 1 and 2). ).
Moreover, the cross-linked rubber made of a rubber composition containing a hydrogenated hydrocarbon resin with a hydrogenation rate exceeding 80% was inferior in rolling resistance (Comparative Example 3). As for wear resistance, the cross-linked rubber (Comparative Example 3) composed of a rubber composition containing a hydrogenated hydrocarbon resin with a hydrogenation rate of more than 80% was obtained by hydrogenating a hydrocarbon resin having the same monomer composition. It was inferior to the rubber cross-linked product (Example 4) made of a hydrocarbon resin hydride formed by the above.

Claims (3)

A rubber composition containing a diene rubber, a hydrocarbon resin hydride, and silica,
The content of the hydrocarbon resin hydride is 1 to 30 parts by mass with respect to 100 parts by mass of the diene rubber,
The silica content is 80 to 200 parts by mass with respect to 100 parts by mass of the diene rubber,
The hydrocarbon resin hydride is
It is obtained by hydrogenating a hydrocarbon resin containing an aliphatic monomer unit and an aromatic monomer unit,
The hydrogenation rate is in the range of 0.1 to 80%,
The weight average molecular weight (Mw) is within the range of 700 to 6,000,
The number average molecular weight (Mn) is within the range of 400 to 3,000,
Z-average molecular weight (Mz) is in the range of 1,500 to 20,000,
The ratio of weight average molecular weight to number average molecular weight (Mw/Mn) is in the range of 1.0 to 4.0,
The ratio of the Z-average molecular weight to the weight-average molecular weight (Mz/Mw) is within the range of 1.0 to 4.0,
The softening point is within the range of 80 to 150 ° C.,
The hydrocarbon resin is
10 to 60% by mass of 1,3-pentadiene monomer units,
1 to 30% by mass of alicyclic monoolefin monomer units having 4 to 6 carbon atoms,
1 to 50% by mass of an acyclic monoolefin monomer unit having 4 to 8 carbon atoms,
0 to 10% by mass of alicyclic diolefin monomer units, and
Containing 0.1 to 50% by mass of the aromatic monomer unit,
rubber composition. The rubber composition according to claim 1, wherein the aromatic monomer contains at least one selected from the group consisting of styrene compounds, indene compounds and C9 fractions. A pneumatic tire using the rubber composition according to claim 1 or 2 for a tread.