KR102640782B1 - Random copolymer, method for producing crumb, and pneumatic tire - Google Patents

Abstract

[Project] Provide random copolymerization that can appropriately control the particle size and moisture content of crumb.
[Solution] A random copolymer that has an aromatic vinyl monomer unit, a conjugated diene monomer unit, and an ethylene structure, has a unimodal molecular weight distribution by GPC, and has a molecular weight distribution of 1.30 to 1.75.

Description

Random copolymer, method for producing crumb, and pneumatic tire {RANDOM COPOLYMER, METHOD FOR PRODUCING CRUMB, AND PNEUMATIC TIRE}

The present invention relates to random copolymers, methods for making crumbs, and pneumatic tires.

The spread of autonomous driving technology has been expected for a long time, and along with this, there is a demand for reducing the frequency of tire replacement, that is, improving tire durability. In particular, regarding brake performance, it is required to be able to maintain high performance for a longer period of time than before to ensure the safety of passengers.

In order to improve the durability of a tire, it is essential to improve the wear resistance of the tire, and a technology for improving the wear resistance by using a polymer containing an ethylene structure in the tire tread has been disclosed (for example, patent (see Document 1).

As a method of producing a polymer containing an ethylene structure, for example, a method of producing the polymer by adding hydrogen to a conjugated diene polymer having a structural unit of butadiene in the chain is included. For example, Patent Document 1 discloses a method of obtaining a copolymer having an ethylene structure by adding hydrogen to a styrene-butadiene copolymer.

Japanese Patent No. 6004081 Publication

However, the hydrogenated polymer described in Patent Document 1 has the problem of poor processability when used as a tire compound. In Patent Document 1, the processability of a tire compound is evaluated using the adhesion to the roll as an indicator, and generally, the evaluation of the adhesion of the polymer to the roll is also correlated with the evaluation of productivity when manufacturing the polymer. Specifically, hydrogenated polymers with low adhesion have low adhesion of the crumb obtained from the steam stripping process during production, and the crumb tends to be fine. Fine crumbs tend to cause a decrease in dehydration efficiency in the dehydration process following the steam stripping process, which has the problem of increasing the water content in the ultimately obtained hydrogenated polymer product.

Therefore, when using the hydrogenated polymer described in Patent Document 1 as a tire compound, poor processability and an increased moisture content of the hydrogenated polymer product are problems that must be solved.

In the technology disclosed in Patent Document 1, the poor processability when used as a tire compound is improved by blending two types of high molecular hydrogenated polymer and low molecular hydrogenated polymer. However, since high-molecular hydrogenated polymers and low-molecular hydrogenated polymers are manufactured separately, the problem that the moisture content of high-molecular hydrogenated polymers is too high has not been solved.

Therefore, in order to improve productivity when producing hydrogenated polymers, there is a demand for a technique for appropriately controlling the particle size of the crumb obtained in the steam stripping process and appropriately controlling the water content of the hydrogenated polymer.

Therefore, in the present invention, in light of the problems of the prior art described above, the purpose is to provide a random copolymer with excellent productivity by being able to appropriately control the size of the crumb particle size and moisture content.

As a result of intensive study to solve the problems of the above-mentioned prior art, the present inventors found that a random copolymer having a specific structure can solve the problems of the above-mentioned prior art, and came to complete the present invention.

That is, the present invention is as follows.

〔One〕

It has an aromatic vinyl monomer unit, a conjugated diene monomer unit, and an ethylene structure,

The molecular weight distribution by GPC is unimodal,

having a molecular weight distribution of 1.30 to 1.75,

Random copolymer.

〔2〕

The random copolymer according to [1] above, wherein the iodine number is 14 or more and 200 or less.

〔3〕

The random copolymer according to [1] or [2] above, which has a weight average molecular weight of 300,000 to 800,000.

〔4〕

The random copolymer according to any one of [1] to [3] above, wherein the glass transition temperature is -70°C or higher and -50°C or lower.

〔5〕

A method for producing crumb of the random copolymer according to any one of [1] to [4] above,

A process of polymerizing an aromatic vinyl compound and a conjugated diene compound in solution;

Process of obtaining crumb by desolvating from a solution containing a polymer

With

Obtaining crumbs with a median diameter (D50) of 6.0 mm or more and 12.0 mm or less,

How to make crumbs.

〔6〕

The random copolymer according to any one of [1] to [4] above,

Rubber components other than the above random copolymer,

Plasticizer ingredients,

filler ingredients

Including pneumatic tires.

According to the present invention, random copolymerization capable of appropriately controlling the particle size and moisture content of crumb can be provided.

Hereinafter, an embodiment for carrying out the present invention (hereinafter referred to as “this embodiment”) will be described in detail.

In addition, the following embodiments are examples for explaining the present invention, and the present invention is not limited to the following embodiments. The present invention can be implemented with appropriate modifications within the scope of its gist.

[Random copolymer]

The random copolymer of this embodiment is,

It has an aromatic vinyl monomer unit, a conjugated diene monomer unit, and an ethylene structure, has a unimodal molecular weight distribution by GPC (gel permeation chromatography), and has a molecular weight distribution of 1.30 to 1.75.

When the random copolymer of the present embodiment is made into a random copolymer with a weight average molecular weight desirable as a tire composition by specifying the above-described structure, especially the molecular weight distribution, within the above-mentioned range, the crumb particle size does not become too fine, and this results in an excellent crumb. Dehydration efficiency can be achieved.

By setting the molecular weight distribution to the above-mentioned specific range, it is possible to increase the presence ratio of low molecular weight components that are effective in enlarging the crumb particle size, so that the crumb can be appropriately enlarged and the crumb particle size can be prevented from becoming excessively fine.

(GPC curve shape of random copolymer)

The GPC curve of the random copolymer of this embodiment is unimodal.

The fact that the GPC curve is unimodal means that when the dissolution time is used as the change, the slope of the tangent line of the dissolution curve shows 0° only once.

When batch polymerization is performed and a coupling reaction is performed, unless the modification rate is 100%, the coupled product and the polymer before coupling show multiple peaks and do not become unimodal. On the other hand, polymers produced by continuous polymerization have one peak in the GPC curve. When a coupling reaction is performed, a shoulder may form on the small molecule side, but multiple peaks are not formed. Therefore, polymers produced by continuous polymerization may have unimodal GPC curves of random copolymers unless polymers of different molecular weight ranges are blended.

The molecular weight distribution of the random copolymer can be controlled by adjusting the ratio of the height (L) and diameter (D) inside the polymerization reactor.

(Composition of random copolymer)

The random copolymer of this embodiment has an aromatic vinyl monomer unit, a conjugated diene monomer unit, and an ethylene structure.

Here, the “ethylene structure” is a structure using ethylene monomer as a repeating unit, and has a structure where carbons are connected through single bonds.

In addition, the “ethylene structure” is not limited to the case where it is formed by polymerizing ethylene monomer, and also includes the case where the ethylene structure is formed by adding hydrogen to the conjugated diene moiety as described later.

It is preferable from the viewpoint of commercial production that the random copolymer of this embodiment is a hydrogenated copolymer in which an ethylene structure is formed by adding hydrogen to a copolymer having an aromatic portion, which is an aromatic vinyl monomer unit, and a conjugated diene portion, which is a conjugated diene monomer unit. A random copolymer obtained by copolymerizing an aromatic vinyl compound, a conjugated diene compound, and ethylene may be used.

In a hydrogenated copolymer, part or all of the conjugated diene portion is changed to an ethylene structure by adding hydrogen to the double bond portion of the conjugated diene portion, and the content of the ethylene structure can be increased by increasing the hydrogen addition rate.

In addition, when the random copolymer of the present embodiment is a hydrogenated copolymer, polymer chains are formed at both ends of the main chain of the conjugated diene compound (for example, 1,4 copolymers of a polymer using 1,3-butadiene as a monomer). -bond) to form an ethylene structure, and to other forms (e.g., 1,2-bond (vinyl bond) of a polymer using 1,3-butadiene as a monomer) hydrogen is added to the ethylene structure. It is not included in the ethylene structure.

Additionally, the ethylene structure can be calculated from the spectrum reduction rate of the unsaturated bond portion derived from the 1,4-bond of the conjugated diene compound in the spectrum obtained by measuring ¹ H-NMR.

Examples of the aromatic vinyl compound used to form the aromatic vinyl monomer unit include, but are not limited to, styrene, 4-methylstyrene, α-methylstyrene, 1-vinylnaphthalene, 3-vinyltoluene, ethylvinylbenzene, Divinylbenzene, 4-cyclohexylstyrene, 2,4,6-trimethylstyrene, etc. are mentioned. These may be used individually or in combination of two or more types. Among these, styrene is particularly preferable from the viewpoint of practical use such as availability of monomers.

Conjugated diene compounds used to form conjugated diene monomer units include, but are not limited to, the following, for example, 1,3-butadiene, isoprene, 1,3-pentadiene, 2,3-dimethylbutadiene, 2-phenyl- 1,3-butadiene, 1,3-hexadiene, etc. can be mentioned. These may be used individually or in combination of two or more types. Among these, 1,3-butadiene and isoprene are preferable, and 1,3-butadiene is more preferable from the viewpoint of practical use such as availability of monomers.

In the random copolymer of the present embodiment, when the content of chains of 8 or more consecutive aromatic vinyl monomer units is taken as the long chain ratio, it is preferable that the long chain ratio is 10% by mass or less with respect to the total aromatic vinyl monomer units. .

When the long chain ratio is 10% by mass or less, excellent low fuel efficiency tends to be obtained.

Here, the content of long chains of eight or more aromatic vinyl monomer units (long chain ratio) is determined from the ¹ H-NMR spectrum of the random copolymer measured using deuterated chloroform as a solvent, as shown in (a) to (c) below. ) is obtained by calculating the ratio of the integral value in the range (a) to the sum of the integral values in each chemical shift range.

For example, when the aromatic vinyl is styrene, the ratio of the integral value in the range (a) to the sum of the integral values in each range (a) to (c) is calculated, and the ratio of styrene is calculated by multiplying the value by 2.5. It can be calculated. By this, the state of the chain of aromatic vinyl monomer units can be ascertained.

(a) Aromatic vinyl compound chain 8 or more: 6.00≤S<6.68

(b) Aromatic vinyl compound chain 2 to 7: 6.68≤S<6.89

(c) Short chain aromatic vinyl compound: 6.89≤S≤8.00

Additionally, the random copolymer of this embodiment may be modified or unmodified, but it is preferable that it is a hydrogenated modified random copolymer from the viewpoints of brake performance and wear resistance.

The above-mentioned modification refers to the random copolymer being functionalized with a compound having a nitrogen element. The type of modification may be either chain end modification, which modifies the polymer chain terminal, or main chain modification, which copolymerizes a compound having a nitrogen element during polymerization.

(Iodine value of random copolymer)

From the viewpoint of crosslinkability, the random copolymer preferably has an iodine value of 14 or more, more preferably 30 or more, further preferably 70 or more, and even more preferably 100 or more.

Moreover, from the viewpoint of crosslinking density, it is preferably 200 or less, more preferably 180 or less, and even more preferably 160 or less.

Additionally, the iodine value can be measured by the method described in the Examples described later.

The iodine value of the random copolymer of this embodiment can be controlled within the above range by adjusting the mass ratio of the conjugated diene compound and aromatic vinyl monomer in the random copolymer, and the hydrogen conversion rate.

Specifically, when the mass ratio of the aromatic vinyl monomer in the random copolymer is 30% by mass, the iodine value can be controlled to 100 or more by setting the hydrogen conversion ratio to 69% or less.

Additionally, when the hydrogen conversion rate is set to 70%, the iodine value can be controlled to 100 or more by setting the ratio of aromatic vinyl monomer in the random copolymer to 29 mass% or less.

(Hydrogenation rate of random copolymer)

The hydrogenation rate (proportion hydrogenated to the conjugated diene portion) of the random copolymer of this embodiment is preferably 50 mol% or more, more preferably 60 mol% or more, and even more preferably 70 mol% from the viewpoint of crosslinkability. That's it. Moreover, from the viewpoint of crosslinkability, it is preferably 95 mol% or less, more preferably 90 mol% or less, and even more preferably 85 mol% or less.

Additionally, the hydrogen addition rate can be calculated from the spectrum reduction rate of the unsaturated bond portion of the spectrum obtained by measuring ¹ H-NMR.

(Content of aromatic vinyl monomer units in random copolymer)

Among 100% by mass of the random copolymer of the present embodiment, the content of aromatic vinyl monomer units is preferably 10% by mass or more, more preferably 20% by mass or more, from the viewpoint of wet grip performance when processed into tires. Preferably it is 30% by mass or more, and from the viewpoint of low fuel efficiency, it is preferably 60% by mass or less, and more preferably 50% by mass or less.

In addition, the content of the aromatic vinyl monomer unit can be measured by the method described in the Examples described later.

(Weight average molecular weight of random copolymer)

The weight average molecular weight (Mw) of the random copolymer of this embodiment is preferably 300,000 or more and 800,000 or less.

From the viewpoint of wear resistance when the random copolymer of this embodiment is used in a tire composition, it is preferably 300,000 or more, more preferably 400,000 or more, even more preferably 450,000 or more, and is preferable from the viewpoint of Mooney viscosity. Preferably it is 800,000 or less, more preferably 700,000 or less, even more preferably 600,000 or less, and even more preferably 550,000 or less.

The weight average molecular weight of the random copolymer can be controlled within the above numerical range by adjusting polymerization conditions such as the amount of monomer added, polymerization time, and polymerization temperature in the polymerization process.

(Molecular weight distribution of random copolymer)

The molecular weight distribution (Mw/Mn) of the random copolymer of this embodiment is 1.30 or more and 1.75 or less.

The molecular weight distribution of the random copolymer affects the size of crumbs generated when steam stripping the polymerization solution of the random copolymer.

If the molecular weight distribution is narrow, the crumb becomes fine because the proportion of low molecular weight components with strong adhesiveness is small, and sufficient shear pressure is not applied in the dehydration process using an extruder following the steam stripping process, thereby reducing dehydration efficiency. Additionally, if the molecular weight distribution is too wide, the proportion of low-molecular-weight components with strong adhesiveness increases, resulting in excessively large crumbs. If the crumb is too large, the drying efficiency in the hot box deteriorates, and as a result, the drying efficiency of the crumb deteriorates. In addition, if you focus only on low-molecular components with strong adhesiveness, the amount of low-molecular components increases even if the average molecular weight is small. In this case, the crumb increases, but the dehydration efficiency tends to decrease. Therefore, from the viewpoint of improving production efficiency, it is necessary to reduce the overall molecular weight. It is more appropriate to control the molecular weight distribution than to control the molecular weight distribution.

From the above-mentioned point, the molecular weight distribution of the random copolymer of the present embodiment is set to be 1.30 or more, preferably 1.40 or more, and more preferably 1.50 or more from the viewpoint of increasing the average particle size of crumbs generated during steam stripping. .

Additionally, from the viewpoint of preventing the average particle diameter of crumb from becoming too large, the molecular weight distribution of the random copolymer of this embodiment is set to 1.75 or less, preferably 1.70 or less, and more preferably 1.65 or less.

In the continuous polymerization process, means of controlling the molecular weight distribution of the random copolymer include a method of adjusting the aspect ratio (L/D) of the polymerization reactor and a method of adjusting the polymerization temperature.

In order to control the molecular weight distribution to 1.75 or less, the L/D of the polymerization reactor is preferably 4.0 or more, more preferably 6.0 or more, and even more preferably 7.0 or more.

Likewise, from the viewpoint of controlling the molecular weight distribution to 1.75 or less, the temperature of the polymerization reactor is preferably 80°C or lower, more preferably 75°C or lower, and even more preferably 72°C or lower.

On the other hand, from the viewpoint of controlling the molecular weight distribution to 1.3 or more, it is preferable that L/D is 1.0 or more in the continuous polymerization process, more preferably 2.0 or more, and even more preferably 3.0 or more.

Additionally, in order to control molecular weight distribution, it is desirable to select a monomer that polymerizes quantitatively and side reactions are unlikely to occur. 1,3-butadiene and isoprene are preferred as conjugated diene compounds from the viewpoint of making anionic polymerization progress quantitatively and controlling molecular weight distribution because side reactions are unlikely to occur.

Similarly, from the viewpoint of molecular weight distribution control, the aromatic vinyl compound is preferably styrene or 4-methylstyrene.

In addition, the weight average molecular weight (Mw) and number average molecular weight (Mn) are measured by the method described in the Examples described later.

(Glass transition temperature of random copolymer)

The glass transition temperature (Tg) of the random copolymer of this embodiment is preferably -70°C or higher, more preferably -50°C or higher, more preferably -40°C or higher, and -30°C or higher from the viewpoint of braking performance. It is more desirable than this. Additionally, from the viewpoint of the low-temperature characteristics of the tire, -10°C or lower is preferable, -15°C or lower is more preferable, -20°C or lower is still more preferable, and -50°C or lower is still more preferable.

The Tg of the random copolymer can be controlled by adjusting the composition ratio of the aromatic vinyl monomer unit and the conjugated diene monomer unit and the iodine value.

Specifically, the Tg of the random copolymer can be increased by increasing the composition ratio of the aromatic vinyl monomer unit, and the Tg of the random copolymer can be increased by increasing the amount of 1,2-bonds in the conjugated diene monomer unit. More specifically, when the content of the aromatic vinyl monomer unit in the random copolymer is 20% by mass, Tg can be set to -50°C or higher by setting the iodine value to about 38 to 94. On the other hand, when the iodine value is set to 110, Tg can be set to -50°C or more by setting the content of the aromatic vinyl monomer unit to 20% by mass or more.

In addition, the glass transition temperature (Tg) can be measured by the method described in the Examples described later.

[Method for producing random copolymer]

The random copolymer of this embodiment can be produced through a polymerization process, a modification process, and a hydrogenation process.

(polymerization process)

There are no particular restrictions on the polymerization method of the random copolymer, and all of the solution polymerization method, gas phase polymerization method, and bulk polymerization method can be used, but the solution polymerization method is particularly preferable from the viewpoint of commercial production.

In addition, the polymerization format is preferably continuous in this embodiment.

When the solution polymerization method is used, the monomer concentration in the solution is preferably 5% by mass or more, and more preferably 10% by mass or more. When the monomer concentration in the solution is 5% by mass or more, the amount of random copolymer obtained is sufficient, which is preferable from the viewpoint of cost. Additionally, the monomer concentration in the solution is preferably 50% by mass or less, and more preferably 30% by mass or less. If the monomer concentration in the solution is 50% by mass or less, the solution viscosity can be prevented from becoming too high, stirring can be easily performed, and the polymerization process tends to be easy to perform.

<Polymerization initiator>

When anionic polymerization is performed in the polymerization process, there is no particular limitation as a polymerization initiator, but an organolithium compound is preferably used.

The organic lithium compound preferably has an alkyl group having 2 to 20 carbon atoms, for example, ethyl lithium, n-propyl lithium, isopropyl lithium, n-butyl lithium, sec-butyl lithium, tert-butyl lithium, and tert-octyl lithium. , n-decyllithium, phenyllithium, 2-naphthyllithium, 2-butyl-phenyllithium, 4-phenyl-butyllithium, cyclohexyllithium, cyclopentyllithium, reaction products of diisopropenylbenzene and butyllithium, etc. I can hear it. Among these, n-butyllithium and sec-butyllithium are preferable from the viewpoint of ease of availability, safety, etc.

When performing coordination polymerization in the polymerization process, it is preferable to use, for example, a polymerization catalyst composition described in Japanese Patent Application Laid-Open No. 2020-45500 as a polymerization initiator.

<Polymerization method>

There are no particular restrictions on the method for producing a random copolymer by anionic polymerization or coordination polymerization using a polymerization initiator, and conventionally known methods can be used.

Specifically, in an organic solvent inert to the reaction, for example, a hydrocarbon-based solvent such as an aliphatic, alicyclic, or aromatic hydrocarbon compound, for example, butyllithium is used as a polymerization initiator, and if necessary, a randomizer described later is present. The desired random copolymer can be obtained by polymerizing styrene, 1,3-butadiene, ethylene, etc. under

<Hydrocarbon-based solvent>

The hydrocarbon-based solvent preferably has 3 to 8 carbon atoms, but is not limited to the following, and examples include propane, n-butane, isobutane, n-pentane, isopentane, n-hexane, cyclohexane, propene, 1 -butene, isobutene, trans-2-butene, cis-2-butene, 1-pentene, 2-pentene, 1-hexene, 2-hexene, benzene, toluene, xylene, ethylbenzene, etc.

These may be used individually, or two or more types may be mixed and used.

<Randomizer in anionic polymerization>

The randomizer refers to controlling the microstructure of the conjugated diene portion in the copolymer, such as increasing 1,2-bonds in butadiene and 3,4-bonds in isoprene, or monomer units in the copolymer. It is a compound that has functions such as control of composition distribution, for example, randomization of styrene units and butadiene units in a styrene-butadiene copolymer.

There are no particular restrictions on this randomizer, and any of the known compounds commonly used as conventional randomizers can be used. Although not limited to the following, examples include dimethoxybenzene, tetrahydrofuran, dimethoxyethane, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, 2,2-di(2-tetrahydrofuryl)propane, trimethylene glycol Ethers such as ethylamine, pyridine, N-methylmorpholine, N,N,N',N'-tetramethylethylenediamine, and 1,2-dipiperidinoethane, and tertiary amines. Additionally, potassium salts such as potassium-t-amylate and potassium-t-butoxide, and sodium salts such as sodium-t-amylate can also be used.

One type of these randomizers may be used individually, or two or more types may be used in combination.

Additionally, the amount of randomizer used is preferably 0.01 mole equivalent or more, and more preferably 0.05 mole equivalent or more per mole of the organic lithium compound that is the polymerization initiator. By setting the amount of randomizer used to 0.01 molar equivalent or more, an additive effect is obtained and randomization tends to become easier. Additionally, the amount of randomizer used is preferably 1,000 mol equivalents or less per mole of the organic lithium compound, and more preferably 500 mol equivalents or less. When the amount of the randomizer used is 1000 molar equivalents or less, the monomer reaction rate can be prevented from changing significantly, and randomization tends to become easier.

<Reaction temperature>

The reaction temperature during polymerization is not particularly limited as long as the reaction proceeds appropriately, but is preferably -10°C to 100°C, and more preferably 25°C to 70°C.

(denaturation process)

A functional group that interacts with silica can be introduced into the polymerization terminal of the random copolymer by reacting the active end of the random copolymer obtained through the polymerization step with a compound having a functional group that interacts with silica. As a result, a random copolymer whose polymerization-terminated terminal is modified is obtained.

The random copolymer used in the modification reaction (hereinafter also referred to as terminal modification reaction) may have an unmodified or modified polymerization initiation terminal as long as it has an active terminal.

In addition, the compound used in the modification step is not particularly limited as long as it has a functional group that interacts with silica and can react with the polymerization active terminal, but for example, a terminal modifier containing a tin atom or nitrogen atom may be used. It is preferable, and it is more preferable to use a terminal modifying agent containing a nitrogen atom.

The denaturation process also includes a coupling process that involves an increase in molecular weight. Specifically, a random copolymer with a branched structure can be obtained by reacting the active terminal with a coupling agent having a plurality of reaction sites.

As a coupling agent containing nitrogen is called a denaturant, a coupling effect is obtained through a denaturation process by selecting a compound having a coupling function as a denaturant.

In denaturation reactions involving an increase in molecular weight, the denaturation rate (coupling rate) affects the molecular weight distribution. Therefore, from the viewpoint of controlling the molecular weight distribution to 1.75 or less, the denaturation rate is preferably 60% or more, more preferably 70% or more, and even more preferably 75% or more.

When a denaturant having multiple functional groups is used, a multi-branched polymer is produced by coupling, and regardless of the number of functional groups, when the denaturation rate is high, the molecular weight distribution tends to shift while maintaining sharpness.

Since the structure of the modifier has little influence on the molecular weight distribution, it can be selected depending on the function expected from the random copolymer to be produced.

Additionally, the denaturation rate can be measured by the method described in the Examples described later.

As terminal modifiers containing nitrogen atoms, from the viewpoint of polymerization productivity and high denaturation rate, isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, nitrogen-containing carbonyl compounds, nitrogen-containing vinyl compounds, and nitrogen-containing epoxy. Compounds, nitrogen group-containing alkoxysilane compounds, etc. can be cited as preferable examples.

As terminal modifiers containing these nitrogen atoms, nitrogen group-containing alkoxysilane compounds are more preferable from the viewpoint of polymerization productivity, high denaturation rate, and tensile strength when used as tires.

Examples of the nitrogen group-containing alkoxysilane compound include, but are not limited to, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2- Diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-(4-trimethoxysilylbutyl)-1-aza-2- Silacyclohexane, 2,2-dimethoxy-1-(5-trimethoxysilyl pentyl)-1-aza-2-silacycloheptane, 2,2-dimethoxy-1-(3-dimethoxymethylsilylpropyl) )-1-aza-2-silacyclopentane, 2,2-diethoxy-1-(3-diethoxyethylsilylpropyl)-1-aza-2-silacyclopentane, 2-methoxy, 2-methyl- 1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2-ethoxy,2-ethyl-1-(3-triethoxysilylpropyl)-1-aza-2-sila Cyclopentane, 2-methoxy, 2-methyl-1-(3-dimethoxymethylsilylpropyl)-1-aza-2-silacyclopentane, and 2-ethoxy,2-ethyl-1-(3-die Toxyethylsilylpropyl)-1-aza-2-silacyclopentane, tris(3-trimethoxysilylpropyl)amine, tris(3-methyldimethoxysilylpropyl)amine, tris(3-triethoxysilylpropyl) Amine, tris(3-methyldiethoxysilylpropyl)amine, tris(trimethoxysilylmethyl)amine, tris(2-trimethoxysilylethyl)amine, and tris(4-trimethoxysilylbutyl)amine, tetra kiss[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine , tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, and N ¹ -(3-(bis(3-(trimethoxysilyl)propyl)amino)propyl)-N ¹ -methyl-N ³ -(3-(methyl(3-(trimethoxysilyl)propyl)amino)propyl)-N ³ -(3-(trimethoxysilyl)propyl)-1,3-propanediamine. You can.

The terminal modification reaction can be performed, for example, as a solution reaction. This solution reaction may be performed using a solution containing unreacted monomers after completion of the polymerization reaction in the polymerization step, or may be performed after isolating the copolymer contained in the solution and dissolving it in a suitable solvent such as cyclohexane. It's okay too. Additionally, since the polymerization type is continuous, it is preferable that the terminal modification reaction is also continuous.

At this time, the method of adding the terminal modifier is not particularly limited, and examples include a method of adding it all at once, a method of dividing it into parts, and a method of adding it continuously.

The amount of the compound used in the terminal modification reaction may be appropriately set depending on the type of compound used in the reaction, but is preferably 0.1 molar equivalent or more, more preferably 0.3 molar equivalent, relative to the metal atom involved in the polymerization reaction contained in the polymerization initiator. It is more than molar equivalent. By setting the amount to 0.1 molar equivalent or more, the modification reaction can sufficiently proceed, and the dispersibility of silica can be appropriately improved.

The temperature of the terminal modification reaction is usually the same as the temperature of the polymerization reaction, and is preferably -20 to 150°C, more preferably 0 to 120°C, and even more preferably 20 to 100°C. When the temperature of the modification reaction is low, the viscosity of the modified copolymer tends to increase.

On the other hand, when the temperature of the denaturation reaction is high, the polymerization active terminal becomes easily deactivated. The reaction time for the denaturation reaction is preferably 1 minute to 5 hours, more preferably 2 minutes to 1 hour.

(Reaction stop process)

Anionic polymerization can be stopped by addition of a known reaction terminator. Such reaction terminators are not limited to the following, but examples include alcohols such as methanol, ethanol, and isopropanol, polar solvents having active protons such as acetic acid, and mixtures thereof, or these polar solvents and hexane, cyclohexane, etc. Examples include mixed solutions of non-polar solvents.

The addition amount of the reaction terminator is usually sufficient in an equimolar amount or a double molar amount relative to the anionic polymerization initiator.

(Hydrogen addition process)

When the random copolymer of this embodiment is used as a hydrogenated copolymer, there is no particular limitation on the hydrogenation method and reaction conditions, and hydrogenation may be performed using a known method and under known conditions.

It is usually carried out at 20 to 150°C, under hydrogen pressurization of 0.1 to 10 MPa, and in the presence of a hydrogenation catalyst.

Additionally, the hydrogenation rate can be controlled by adjusting the amount of hydrogenation catalyst, hydrogen pressure during the hydrogenation reaction, reaction time, etc.

As a hydrogenation catalyst, a compound containing any of metals from groups 4 to 11 of the periodic table can usually be used. Although not limited to the following, for example, a compound containing Ti, V, Co, Ni, Zr, Ru, Rh, Pd, Hf, Re, or Pt atoms can be used as a hydrogenation catalyst. More specifically, metallocene compounds such as Ti, Zr, Hf, Co, Ni, Pd, Pt, Ru, Rh, and Re; Supported heterogeneous catalysts in which metals such as Pd, Ni, Pt, Rh, and Ru are supported on a carrier such as carbon, silica, alumina, and diatomaceous earth; a homogeneous Ziegler-type catalyst combining an organic salt or acetylacetone salt of a metal element such as Ni or Co and a reducing agent such as organic aluminum; Organometallic compounds or complexes such as Ru and Rh; Examples include fullerene and carbon nanotubes in which hydrogen is stored.

Among these, a metallocene compound containing any of Ti, Zr, Hf, Co, and Ni is preferable from the viewpoint of being able to undergo a hydrogenation reaction in a homogeneous system in an inert organic solvent. Additionally, a metallocene compound containing any of Ti, Zr, and Hf is preferable.

Hydrogenation catalysts may be used individually, or may be used in combination of two or more types.

A preferable manufacturing method for obtaining the random copolymer of this embodiment is to carry out solution polymerization, use the obtained polymer solution as is, perform modification treatment as needed, and then subject it to a hydrogenation step as needed.

The random copolymer of this embodiment is obtained by removing the solvent from the polymer solution obtained above and isolating the polymer. Examples of methods for isolating the random copolymer include known solvent removal methods such as steam stripping, and methods of isolating by drying operations such as heat treatment using a dehydration extruder, dry extruder, and conveyor.

(Crum production method)

The random copolymer of this embodiment can be isolated as crumb by removing the solvent from the polymerization solution.

Specifically, crumb is obtained by removing the solvent in a steam stripping process.

The particle size of the obtained crumb affects the drying ability in the dehydration extrusion process, dry extrusion process, and conveyor process following the solvent removal process. If the average particle size of the crumb is too large, the dehydration efficiency on the drying conveyor decreases and the moisture content in the product bale increases. On the other hand, if the crumb average particle size is too fine, sufficient shear pressure is not applied in the dehydration extruder or dry extruder, resulting in lower dehydration efficiency and higher moisture content in the product bale.

From the viewpoint of preventing the crumb particle size from becoming too large, the steam stripping temperature is preferably 70°C or higher, more preferably 80°C or higher, and even more preferably 90°C or higher. Also, from the viewpoint of steam usage, the temperature of steam stripping is preferably 110°C or lower, more preferably 100°C or lower, and even more preferably 95°C or lower.

<Crum's entrance>

It is desirable to determine the average particle size of crumb based on the particle size distribution of crumb. In particular, the median diameter (D50), which is the median of the crumb particle size, is an important value in the drying process.

There is a distribution in the particle size of crumb, and the presence ratio of crumb with large particle size and crumb with fine particle size greatly affects the dehydration efficiency of the entire crumb. Therefore, the median value of D50 is an indicator of the drying efficiency of the entire crumb.

Crumb's D50 can be controlled by adjusting the molecular weight distribution of the random copolymer to 1.30 to 1.75 as described above.

From the viewpoint of dehydration efficiency in the crumb dehydration extruder, the median diameter (D50) of the crumb of the random copolymer of the present embodiment is preferably 6.0 mm or more, more preferably 8.0 mm or more, and still more preferably 8.5 mm or more. , more preferably 9.0 mm or more.

From the viewpoint of dehydration efficiency on the crumb drying conveyor, the D50 of the crumb of the random copolymer of this embodiment is preferably 12.0 mm or less, more preferably 11 mm or less, and still more preferably 10 mm or less.

Crumb's D50 can be measured by the method described in the Examples described later.

[Rubber composition]

A rubber composition is obtained by combining the random copolymer of this embodiment with other rubber components other than the random copolymer, plasticizer components, filler components, and other additives as necessary.

<Other rubber components>

The rubber composition may contain a known polymer blend as a rubber component other than the random copolymer of the present embodiment. In addition to the above polymer blends, those widely used in general tire rubber compositions can be used, such as natural rubber (NR), isoprene rubber (IR), styrene-butadiene rubber (SBR), butadiene rubber (BR), etc. there is.

These may be used individually, or two or more types may be used together.

In the above-mentioned rubber composition, the content of the filler component (A) and the content of the plasticizer component (B) are not particularly limited, and the content of the filler component is preferably 20 to 50% by mass, based on 100% by mass of the entire rubber composition. The content is preferably 10 to 40 mass%.

<Filler ingredients>

The filler component is blended into the rubber composition for the purpose of reinforcing the rubber, and includes, but is not limited to, silica, calcium carbonate, mica, aluminum hydroxide, magnesium oxide, magnesium hydroxide, clay, talc, alumina, titanium oxide, Examples include white fillers (inorganic fillers) such as mica and carbon black. These may be used individually, or two or more types may be used together. In particular, silica and carbon black are preferable, and their combined use is more preferable.

The silica is not particularly limited, and examples include dry-processed silica (anhydrous silica) and wet-processed silica (hydrated silica), but wet-processed silica is preferred because it contains many silanol groups.

The nitrogen adsorption specific surface area (N ₂ SA) of silica is preferably 60 m2/g or more, more preferably 120 m2/g or more from the viewpoint of wear resistance, and preferably 300 m2/g or less from the viewpoint of low fuel efficiency. Preferably it is 200 m2/g or less.

In addition, the nitrogen adsorption specific surface area of silica is a value measured by the BET method in accordance with ASTM D3037-81.

From the viewpoint of low fuel efficiency, the silica content is preferably 30 parts by mass or more, more preferably 50 parts by mass or more, with respect to 100 parts by mass of the rubber component including the random copolymer of the present embodiment and other rubber components. From the viewpoint of Mooney viscosity, it is preferably 120 parts by mass or less, more preferably 100 parts by mass or less.

Carbon blacks include, for example, furnace blacks such as SAF, ISAF, HAF, MAF, FEF, SRF, GPF, APF, FF, CF, SCF and ECF; Acetylene black (acetylene carbon black); thermal blacks such as FT and MT (thermal carbon black); Channel Black (Channel Carbon Black) such as EPC, MPC and CC; Graphite, etc. may be mentioned. These can be used one type or in combination of two or more types.

The nitrogen adsorption specific surface area (N ₂ SA) of carbon black is usually 5 to 200 m2/g, and is preferably 50 m2/g or more, more preferably 80 m2/g or more from the viewpoint of wear resistance, and also from the viewpoint of low fuel efficiency. It is preferably 150 m2/g or less, more preferably 120 m2/g or less.

In addition, the absorption amount of dibutyl phthalate (DBP) of carbon black is usually 5 to 300 mL/100 g, with the lower limit being 80 mL/100 g and the upper limit being preferably 180 mL/100 g.

The nitrogen adsorption specific surface area can be measured according to ASTM D4820-93, and the corresponding DBP absorption amount can be measured according to ASTM D2414-93.

From the viewpoint of wear resistance, the carbon black content is preferably 1 part by mass or more, more preferably 3 parts by mass or more, with respect to 100 parts by mass of the rubber component including the random copolymer of the present embodiment and other rubber components, Also, from the viewpoint of low fuel efficiency, the amount is preferably 30 parts by mass or less, more preferably 15 parts by mass or less, relative to 100 parts by mass of the rubber component.

Silica is preferably used in combination with a silane coupling agent. As a silane coupling agent, a conventionally known one can be used. Although not limited to the following, examples include bis(3-triethoxysilylpropyl)tetrasulfide, bis(2-triethoxysilylethyl)tetrasulfide, and bis(3-trimethoxysilylpropyl)tetrasulfide. Feed, bis(2-trimethoxysilylethyl)tetrasulfide, bis(3-triethoxysilylpropyl)trisulfide, bis(3-trimethoxysilylpropyl)trisulfide, bis(3-triethyl) Toxysilylpropyl)disulfide, bis(3-trimethoxysilylpropyl)disulfide, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyltetrasulfide, 3-trimethoxysilylpropylbenzothia Sulfides such as zolyl tetrasulfide, 3-triethoxysilylpropylbenzothiazoletetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, and 3-trimethoxysilylpropyl methacrylate monosulfide. Mercapto series such as 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, and 2-mercaptoethyltriethoxysilane, vinyl triethoxy Silane, vinyl such as vinyltrimethoxysilane, 3-aminopropyltriethoxysilane, 3-aminopropyltrimethoxysilane, 3-(2-aminoethyl)aminopropyltriethoxysilane, 3-(2- Amino ethyl)aminopropyltrimethoxysilane, γ-glycidoxypropyltriethoxysilane, γ-glycidoxypropyltrimethoxysilane, γ-glycidoxypropylmethyldiethoxysilane, γ-glycidoxypropyltrimethoxysilane Glycidoxy series such as sidoxypropylmethyldimethoxysilane, nitro series such as 3-nitropropyltrimethoxysilane and 3-nitropropyltriethoxysilane, 3-chloropropyltrimethoxysilane, and 3-chloropropyltriethoxysilane. and chloro-based ones such as oxysilane, 2-chloroethyltrimethoxysilane, and 2-chloroethyltriethoxysilane.

In addition, the above-mentioned silane coupling agents may be used individually or in combination of two or more types. In particular, from the viewpoint of coupling effect, processability, and cost, sulfide-based silane coupling agents are preferable, and bis(3-triethoxysilylpropyl)tetrasulfide and bis(3-triethoxysilylpropyl) are preferred. ) Disulfide is more preferred.

From the viewpoint of low fuel efficiency and wear resistance, the content of the silane coupling agent is preferably 3 parts by mass or more, more preferably 5 parts by mass or more, per 100 parts by mass of silica, and from the viewpoint of Mooney viscosity, the content is 100 parts by mass of silica. It is preferably 15 parts by mass or less, more preferably 10 parts by mass or less.

<Plasticizer ingredients>

Plasticizer components include, but are not limited to, oils, resins, anti-aging agents, waxes, stearic acids, vulcanization accelerators, etc., for example. These may be used individually, or two or more types may be used together.

Examples of the oil include aromatic mineral oil (viscosity specific constant (V.G.C. value) 0.900 to 1.049), naphthenic mineral oil (V.G.C. value 0.850 to 0.899), and paraffinic mineral oil (V.G.C. value 0.790 to 0.849). The polycyclic aromatic content of the extender oil is preferably less than 3% by mass, more preferably less than 1% by mass. The polycyclic aromatic content is measured according to the British Petroleum Institute 346/92 method. Moreover, the aromatic compound content (CA) of the extender oil is preferably 20% by mass or more. These extender oils may be used in combination of two or more types.

From the viewpoint of the Mooney viscosity of the rubber composition, the oil content is preferably 5 parts by mass or more, more preferably 10 parts by mass, with respect to 100 parts by mass of the rubber component including the random copolymer of the present embodiment and other rubber components. From the viewpoint of low fuel efficiency, it is preferably 50 parts by mass or less, more preferably 40 parts by mass or less, with respect to 100 parts by mass of the rubber component including the random copolymer of the present embodiment and other rubber components.

The resin is not limited to the following, but examples include C5-based petroleum resin, C9-based petroleum resin, coumarone indene resin, indene resin, phenol-based resin, copolymers of α-methylstyrene and/or styrene, etc. .

These may be used individually, or two or more types may be used together. In particular, copolymers of coumarone indene resin, phenolic resin (particularly terpene phenol resin), α-methylstyrene and/or styrene are preferred, and copolymers of α-methylstyrene and styrene are more preferred.

From the viewpoint of the wet grip performance of the rubber composition, the resin content is preferably 1 part by mass or more, more preferably 3 parts by mass or more, per 100 parts by mass of the rubber component, and from the viewpoint of low fuel efficiency, the random of the present embodiment It is preferably 20 parts by mass or less, more preferably 10 parts by mass or less, with respect to 100 parts by mass of the rubber component including the copolymer and other rubber components.

<Additives>

In addition to the above, additives such as anti-aging agents, waxes, stearic acid, and vulcanization accelerators may be added to the rubber composition.

Anti-aging agents include, but are not limited to, naphthylamine-based anti-aging agents such as phenyl-α-naphthylamine; Diphenylamine-based anti-aging agents such as octylated diphenylamine and 4,4'-bis(α,α'-dimethylbenzyl)diphenylamine; N-phenyl-N'-isopropyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N,N'-di-2-naphthyl- p-phenylenediamine-based anti-aging agents such as p-phenylenediamine; Quinoline-based anti-aging agents such as polymers of 2,2,4-trimethyl-1,2-dihydroquinoline; monophenol-based anti-aging agents such as 2,6-di-t-butyl-4-methylphenol and styrenated phenol; Bis, tris, and polyphenol-based anti-aging agents such as tetrakis-[methylene-3-(3',5'-di-t-butyl-4'-hydroxyphenyl)propionate]methane, etc. can be mentioned. These may be used individually or in combination of two or more types. In particular, p-phenylenediamine-based anti-aging agents are preferred, and N-phenyl-N'-isopropyl-p-phenylenediamine is more preferred. The content of the anti-aging agent is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4 parts by mass, with respect to 100 parts by mass of the rubber component including the random copolymer of the present embodiment and other rubber components.

The wax is not limited to the following, but examples include petroleum waxes such as paraffin wax and microcrystalline wax; Natural waxes such as plant wax and animal wax; and synthetic waxes such as polymers such as ethylene and propylene.

These may be used individually, or two or more types may be used together. In particular, petroleum wax is preferable, and paraffin wax is more preferable. The wax content is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4 parts by mass, with respect to 100 parts by mass of the rubber component including the random copolymer of the present embodiment and other rubber components.

As stearic acid, conventionally known ones can be used. For example, products from Nichiyu Co., Ltd., NOF Co., Ltd., Gao Co., Ltd., Wako Pure Chemical Industries, Ltd., and Chiba Shibosan Co., Ltd. can be used. These may be used individually, or two or more types may be used together. The content of stearic acid is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4 parts by mass, with respect to 100 parts by mass of the rubber component including the random copolymer of the present embodiment and other rubber components.

The vulcanization accelerator is not limited to the following, but examples include thiazole-based vulcanization accelerators such as 2-mercaptobenzothiazole, dibenzothiazyl disulfide, and N-cyclohexyl-2-benzothiazylsulfenamide; Thiuram-based vulcanization accelerators such as tetramethylthiuram monosulfide and tetramethylthiuram disulfide; N-cyclohexyl-2-benzothiazolesulfenamide, N-t-butyl-2-benzothiazolesulfenamide, N-oxyethylene-2-benzothiazolesulfenamide, N-oxyethylene-2-benzothiazolesulfenamide , N,N'-diisopropyl-2-benzothiazolesulfenamide, and other sulfenamide-based vulcanization accelerators; and guanidine-based vulcanization accelerators such as diphenylguanidine, diorthotolylguanidine, and orthotolylbiguanidine. These may be used individually, or two or more types may be used together. In particular, sulfenamide-based vulcanization accelerators are preferable, and N-cyclohexyl-2-benzothiazolesulfenamide is more preferable because the effects of the present invention are more suitably obtained. Additionally, it is also preferable to further use a guanidine-based vulcanization accelerator. The content of the vulcanization accelerator is preferably 0.1 to 5 parts by mass, more preferably 0.2 to 4 parts by mass, with respect to 100 parts by mass of the rubber component including the random copolymer of the present embodiment and other rubber components.

<Vulcanizing agent, vulcanization activator, organic peroxide, processing aid, anti-aging agent>

In addition to the above components, the rubber composition contains a vulcanizing agent such as sulfur; Vulcanization activators such as zinc oxide; organic peroxides; Processing aids such as lubricants; Compounding agents conventionally used in the rubber industry, such as anti-aging agents, can be used.

The vulcanizing agent is not particularly limited, but sulfur can be suitably used. The sulfur content is preferably 0.5 to 5 parts by mass, more preferably 1 to 3 parts by mass, with respect to 100 parts by mass of the rubber component including the random copolymer of the present embodiment and other rubber components. Thereby, the effect of this invention is obtained more suitably.

(Method for producing rubber composition)

The rubber composition is prepared by a general method. That is, it can be manufactured by kneading each of the above components using a Banbury mixer, kneader, open roll, etc., and then vulcanizing them.

(Use of rubber composition)

The rubber composition containing the random copolymer of the present embodiment can be used in each member of a tire (tread, sidewall, carcass, belt, bead, clinch, chafer, etc.), and is particularly suitably used as a tread. In the case of a two-layer tread, it consists of a surface layer (cap tread) and an inner layer (base tread).

A tread with a multi-layer structure can be manufactured by a method of joining sheet-like sheets into a predetermined shape, or by charging two or more extruders to form two or more layers at the head exit of the extruders.

<Pneumatic tires>

The rubber composition containing the random copolymer of this embodiment is suitable as a raw material for pneumatic tires. Pneumatic tires can be manufactured by known methods using the above rubber composition. That is, rubber components, plasticizer components, filler components, and other various additives are mixed as needed, extruded according to the shape of each tire member such as the tread at the non-vulcanization stage, and molded on a tire molding machine together with other tire members. By doing this, an unvulcanized tire can be formed, and a pneumatic tire can be obtained by heating and pressurizing this unvulcanized tire in a vulcanizer.

The pneumatic tire of this embodiment is suitably used as a passenger car tire, a truck/bus tire, a two-wheeled vehicle tire, a racing tire, etc., and is particularly suitably used as a passenger car tire.

[Example]

Hereinafter, the present embodiment will be described in more detail with reference to specific examples and comparative examples, but the present embodiment is not limited at all by the following examples and comparative examples.

Various physical properties in the examples and comparative examples were measured by the method shown below.

(Weight average molecular weight (Mw), molecular weight distribution of random copolymer)

The chromatogram was measured using a GPC measuring device connecting three columns using polystyrene gel as a filler, and the weight average molecular weight (Mw) and molecular weight distribution (Mw/) of the random copolymer were measured based on a calibration curve using standard polystyrene. Mn) was obtained.

THF (tetrahydrofuran) containing 5 mmol/L of triethylamine was used as the eluent.

The columns used were guard column: brand name "TSKguardcolumn SuperH-H" manufactured by Tosoh Corporation, and column: brand name "TSKgel SuperH5000", "TSKgel SuperH6000", and "TSKgel SuperH7000" manufactured by Tosoh Corporation.

An RI detector (trade name “HLC8020” manufactured by Tosoh Corporation) was used under the conditions of an oven temperature of 40°C and a THF flow rate of 0.6 mL/min.

10 mg of the sample for measurement was dissolved in 20 mL of THF to prepare a measurement solution, and 20 μL of the measurement solution was injected into the GPC measurement device and measured.

(Confirmation of unimodal nature of molecular weight distribution of random copolymer)

The fact that the GPC curve is unimodal means that when a random copolymer is analyzed by GPC, the slope of the tangent line of the elution curve when the elution time is used as the change amount shows 0° only once.

A differential elution curve obtained by differentiating the elution curve of the random copolymer obtained in the production example described later was drawn to confirm the unimodal nature.

(denaturation rate of random copolymer)

A random copolymer was used as a sample for measurement, and the chromatogram was measured by applying the adsorption characteristics of the modified basic polymer component to a GPC column using silica gel as a filler.

The adsorption amount on the silica-based column is measured from the difference between the chromatogram of the measurement sample and the measurement sample solution containing low molecular weight internal standard polystyrene measured with a polystyrene-based column and the chromatogram measured with a silica-based column, The denaturation rate was determined.

Specifically, it is as shown below.

Preparation of sample solution for measurement:

10 mg of the sample for measurement and 5 mg of standard polystyrene were dissolved in 20 mL of THF (tetrahydrofuran) to prepare a sample solution for measurement.

GPC measurement conditions using a polystyrene-based column:

Using the product name "HLC-8320GPC" manufactured by Tosoh Corporation, THF was used as an eluent, 10 μL of the sample solution for measurement was injected into the device, and under the conditions of a column oven temperature of 40°C and a THF flow rate of 0.35 mL/min, the RI detector was used. A chromatogram was obtained using . Three columns were connected under the trade name "TSKgel SuperMultiporeHZ-H" manufactured by Tosoh Corporation, and a guard column under the trade name "TSKguardcolumn SuperMP(HZ)-H" manufactured by Tosoh Corporation was used as a guard column at the front end.

GPC measurement conditions using a silica-based column:

Using the product name "HLC-8320GPC" manufactured by Tosoh Corporation, THF was used as an eluent, 50 μL of the sample solution for measurement was injected into the device, and under the conditions of a column oven temperature of 40°C and a THF flow rate of 0.5 mL/min, the RI detector was used. A chromatogram was obtained using . Columns were used by connecting the product names "Zorbax PSM-1000S", "PSM-300S", and "PSM-60S", and the product name "DIOL 4.6 x 12.5 mm 5 micron" was used as a guard column at the front end.

How to calculate denaturation rate:

The total peak area of the chromatogram using a polystyrene-based column is set to 100, the peak area of the sample is set to P1, the peak area of the standard polystyrene is set to P2, the total peak area of the chromatogram using a silica-based column is set to 100, and the peak area of the sample is set to P1. The peak area of P3 and the peak area of standard polystyrene were P4, and the denaturation rate (% by mass) was determined from the following formula.

Denaturation rate (mass%) = [1-(P2×P3)/(P1×P4)]×100

(In the above equation, P1+P2=P3+P4=100.)

(Amount of bonded styrene in random copolymer)

100 mg of the sample was diluted with chloroform to 100 mL in a measuring cylinder and dissolved to serve as a measurement sample. The amount of bound styrene (mass %) relative to 100 mass % of the random copolymer as a sample was measured based on the absorption amount of the ultraviolet ray absorption wavelength (around 254 nm) by the phenyl group of styrene (Measurement device: Spectrophotometer manufactured by Shimadzu Seisakusho Co., Ltd. UV-2450”).

(Amount of 1,2-vinyl bond in butadiene portion of random copolymer)

50 mg of random copolymer as a sample was dissolved in 10 mL of carbon disulfide to serve as a measurement sample. The infrared spectrum was measured in the range of 600 to 1000 cm ^-1 using a solution cell, and the absorbance at a predetermined wave number was calculated according to Hampton's method (method described in RR Hampton, Analytical Chemistry 21,923 (1949)). , the microstructure of the butadiene portion, that is, the amount of 1,2-vinyl bonds (mol%), was determined (measuring device: Fourier transform infrared spectrophotometer “FT-IR230” manufactured by Nippon Bunko Co., Ltd.).

(Hydrogenation rate and ethylene structural amount of random copolymer)

By adding a large amount of methanol to the solution of the random copolymer after the hydrogenation reaction, the conjugated diene polymer before hydrogenation and the hydrogenated conjugated diene polymer were precipitated and recovered.

Next, the hydrogenated conjugated diene polymer was extracted with acetone, and the hydrogenated conjugated diene polymer was vacuum dried. Using this as a sample for ¹ H-NMR measurement, the hydrogenation rate and ethylene structural content were measured.

Conditions are described below.

(Measuring conditions)

Measuring instrument: JNM-LA400 (manufactured by JEOL)

Solvent: Deuterated chloroform

Measurement sample: Extract before and after hydrogenation of polymer

Sample concentration: 50 mg/mL

Observation frequency: 400MHz

Chemical Shift Reference: Tetramethylsilane (TMS)

Pulse Delay: 2.904 seconds

Number of scans: 64

Pulse Width: 45°

Measurement temperature: 26℃

(Iodine value of random copolymer)

The iodine value of the random copolymer was calculated according to the method described in “JIS K 0070:1992”.

(Glass transition temperature of random copolymer: Tg)

Using a random copolymer as a sample, in accordance with ISO 22768:2006, using a differential scanning calorimeter "DSC3200S" manufactured by Mac Science, the temperature was raised from -100°C to 20°C/min under a flow of 50 mL/min of helium. The DSC curve was recorded, and the peak top (Inflection point) of the DSC differential curve was taken as the glass transition temperature.

(Size of crumb of random copolymer)

<Crum production method>

The solvent was removed from the polymerization solution of the random copolymer obtained by the method described in the production example described later by a steam stripping method, and crumb was obtained.

The operation of obtaining the crumb is called crumbing.

The conditions for crumbling are described below.

Water temperature: 90℃

Quantity: 8kg

Stirring tank: Stirring tank with 30L stirring blades

Stirring blades: 2 turbine blades

Stirring vane rotation speed: 500rpm

Amount of polymer used for crumbling: 200g

Addition rate of polymer solution to crumbling bath: 30 g/min.

<Evaluation of Crumb’s Median Diameter (D50)>

The crumbs obtained by crumbling were pounded using a metal mesh sieve (JIS Z 8801-1:2000, manufactured by Okutani Kinzoku Seisakusho Co., Ltd.) and separated into crumbs corresponding to each eye size.

The eye size of the metal mesh used is described below.

22.4mm, 19mm, 16mm, 13.2mm, 9.5mm, 8mm, 6.7mm, 4mm, 3.35mm, 1.7mm

D50 was calculated by measuring the mass of crumbs caught in a sieve of each eye size.

[Preparation of hydrogenation catalyst]

In the examples and comparative examples described later, the hydrogenation catalyst used in producing the random copolymer was prepared by the following method.

Into a nitrogen-purged reaction vessel, 1 liter of dried and purified cyclohexane was added, 100 mmol of bis(η5-cyclopentadienyl)titanium dichloride was added, and while sufficiently stirred, n-hexane containing 200 mmol of trimethyl aluminum was added. The solution was added and reacted at room temperature for about 3 days to obtain a hydrogenation catalyst.

[Preparation Example 1 (Preparation of Random Copolymer 1)]

The internal volume is 10L, the ratio (L/D) of the internal height (L) and diameter (D) is 4.0, it has an inlet at the bottom and an outlet at the top, and has a stirrer, which is a formative reactor with a stirrer, and a jacket for temperature control. Two molded pressure vessels were connected as polymerization reactors.

1,3-butadiene, from which water was previously removed, was mixed at a rate of 22.0 g/min, styrene at 3.9 g/min, and n-hexane at 175.0 g/min. In a static mixer provided in the middle of the pipe supplying this mixed solution to the inlet of the reactor, n-butyllithium for inactivating residual impurities was added and mixed at 6.0 mg/min, and then continuously supplied to the bottom of the reactor.

In addition, 2,2-di(2-tetrahydrofuryl)propane as a polar substance was vigorously mixed with a stirrer at a rate of 0.34 mg/min and n-butyllithium as a polymerization initiator at a rate of 23.8 mg/min. The first reactor was supplied to the bottom of the reactor, and the temperature inside the reactor was maintained at 67°C.

The polymer solution was continuously withdrawn from the top of the first reactor and continuously supplied to the bottom of the second reactor to continue the reaction at 70°C, and was further supplied to the static mixer from the top of the second reactor. In a static mixer, 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azacylolidine is added as a denaturant at a rate of 24.2 mg/min to denature the growing ends. did.

Next, the polymerization solution was placed in a pressure vessel having an internal volume of 20 L, a stirrer having an internal height (L) and diameter (D) ratio (L/D) of 4.0, and a pressure vessel having a stirrer and a jacket for temperature control. 10L was transferred, the internal temperature was set to 80°C, and hydrogen was introduced into the system.

Next, 60 ppm of a hydrogenation catalyst was added based on titanium relative to the amount of input monomer, and the hydrogenation reaction was performed at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C. After reaching the predetermined integrated hydrogen flow rate, the reaction liquid was returned to room temperature and pressure and extracted from the reaction vessel to obtain a polymer solution.

The crumb of random copolymer 1 was obtained by crumbling the obtained polymer solution under the crumbling conditions described above. The crumb was separated by particle size using a metal mesh sieve, and D50 was calculated by measuring the mass fraction for each particle size. After calculating the D50 of the crumb, an analysis sample of Random Copolymer 1 was obtained by drying the crumb in a vacuum dryer heated to 90°C for 2 hours.

The polymerization recipe, physical properties, and characteristics of random copolymer 1 are shown in Table 1.

[Preparation Example 2 (Preparation of Random Copolymer 2)]

The internal volume is 10 L, the ratio (L/D) of the internal height (L) and diameter (D) is 7.0, it has an inlet at the bottom and an outlet at the top, and has a stirrer that is a form reactor with a stirrer and a jacket for temperature control. Two molded pressure vessels were connected as polymerization reactors.

1,3-butadiene, from which water was previously removed, was mixed at a rate of 22.0 g/min, styrene at 3.9 g/min, and n-hexane at 175.0 g/min. In a static mixer provided in the middle of the pipe supplying this mixed solution to the inlet of the reactor, n-butyllithium for inactivating residual impurities was added and mixed at 6.0 mg/min, and then continuously supplied to the bottom of the reactor.

In addition, 2,2-di(2-tetrahydrofuryl)propane as a polar substance was vigorously mixed with a stirrer at a rate of 0.24 mg/min and n-butyllithium as a polymerization initiator at a rate of 19.6 mg/min. The first reactor was supplied to the bottom of the reactor, and the temperature inside the reactor was maintained at 67°C.

The polymer solution was continuously withdrawn from the top of the first reactor and continuously supplied to the bottom of the second reactor to continue the reaction at 70°C, and was further supplied to the static mixer from the top of the second reactor. In a static mixer, 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azacylolidine was added as a denaturant at a rate of 19.9 mg/min to denature the growing ends. did.

Next, the polymerization solution was placed in a pressure vessel having an internal volume of 20 L, a stirrer having an internal height (L) and diameter (D) ratio (L/D) of 4.0, and a pressure vessel having a stirrer and a jacket for temperature control. 10L was transferred, the internal temperature was set to 80°C, and hydrogen was introduced into the system.

Next, 60 ppm of a hydrogenation catalyst was added based on titanium relative to the amount of input monomer, and the hydrogenation reaction was performed at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C. After reaching the predetermined integrated hydrogen flow rate, the reaction liquid was returned to room temperature and pressure and extracted from the reaction vessel to obtain a polymer solution.

The crumb of random copolymer 1 was obtained by crumbling the obtained polymer solution under the crumbling conditions described above. The crumb was separated by particle size using a metal mesh sieve, and D50 was calculated by measuring the weight fraction for each particle size. After calculating the D50 of the crumb, an analysis sample of Random Copolymer 2 was obtained by drying the crumb in a vacuum dryer heated to 90°C for 2 hours.

The polymerization prescription, physical properties, and characteristics of random copolymer 2 are shown in Table 1.

[Preparation Example 3 (Production of Random Copolymer 3)]

The addition rate of n-butyllithium, a polymerization initiator, was set to 33.5 mg/min, the addition rate of 2,2-di(2-tetrahydrofuryl)propane, a polar substance, was set to 0.75 mg/min, and the modifier, 2,2 Random copolymer 1 of [Preparation Example 1] above except that the addition rate of -dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azacylolidine was changed to 34.0 mg/min. Polymerization was performed in the same manner as above.

The polymerization prescription, physical properties, and characteristics of the obtained random copolymer 3 are shown in Table 1.

[Preparation Example 4 (Production of Random Copolymer 4)]

The addition rate of n-butyllithium, a polymerization initiator, was set to 27.5 mg/min, the addition rate of 2,2-di(2-tetrahydrofuryl)propane, a polar substance, was set to 0.51 mg/min, and the modifier, 2,2 Random copolymer 2 of [Preparation Example 2] above except that the addition rate of -dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azacylolidine was changed to 28.0 mg/min. Polymerization was performed in the same manner as above.

The polymerization prescription, physical properties, and characteristics of the obtained random copolymer 4 are shown in Table 1.

[Preparation Example 5 (Production of Random Copolymer 5)]

Polymerization conditions other than changing the amount of hydrogen added were the same as in [Preparation Example 1] above, and random copolymer 5 was obtained.

The polymerization prescription, physical properties, and characteristics of the obtained random copolymer 5 are shown in Table 1.

[Preparation Example 6 (Production of Random Copolymer 6)]

Polymerization conditions other than changing the amount of hydrogen added were the same as in [Preparation Example 2] above, and random copolymer 6 was obtained.

The polymerization prescription, physical properties, and characteristics of the obtained random copolymer 6 are shown in Table 2.

[Preparation Example 7 (Production of Random Copolymer 7)]

The addition rate of styrene was set to 1.3 g/min, the addition rate of butadiene was set to 25 g/min, the addition rate of n-butyllithium as a polymerization initiator was set to 20.1 mg/min, and the polar substance 2,2-di( The addition rate of 2-tetrahydrofuryl)propane is 0.26 mg/min, and the addition rate of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azacylolidine, a denaturant. Polymerization was performed in the same manner as random copolymer 1 in [Preparation Example 1] above, except that the rate was changed to 20.4 mg/min.

The polymerization prescription, physical properties, and characteristics of the obtained random copolymer 7 are shown in Table 2.

[Production Example 8 (Production of Random Copolymer 8)]

Polymerization conditions other than the amount of hydrogen addition were the same as in [Preparation Example 1] above, and random copolymer 8 was obtained.

The polymerization prescription, physical properties, and characteristics of the obtained random copolymer 8 are shown in Table 2.

[Production Example 9 (Production of Random Copolymer 9)]

Polymerization conditions other than the amount of hydrogen addition were the same as in [Preparation Example 2] above, and random copolymer 9 was obtained.

The polymerization prescription, physical properties, and characteristics of the obtained random copolymer 9 are shown in Table 2.

[Production Example 10 (Production of Random Copolymer 10)]

The addition rate of n-butyllithium, a polymerization initiator, is 39.8 mg/min, the addition rate of 2,2-di(2-tetrahydrofuryl)propane, a polar substance, is 0.91 mg/min, and 2,2-dimethoxy, a denaturant. -1-(3-(trimethoxysilyl)propyl)-1,2-azacylolidine was the same as random copolymer 1 of [Preparation Example 1] except that the addition rate was changed to 40.3 mg/min. It was polymerized using this method.

The polymerization prescription, physical properties, and characteristics of the obtained random copolymer 10 are shown in Table 2.

[Preparation Example 11 (Production of Random Copolymer 11)]

The addition rate of n-butyllithium, a polymerization initiator, was 15.1 mg/min, the addition rate of 2,2-di(2-tetrahydrofuryl)propane, a polar substance, was 0.14 mg/min, and 2,2-dimethyl, a denaturant. Same as random copolymer 1 of [Preparation Example 1] above except that the addition rate of toxy-1-(3-(trimethoxysilyl)propyl)-1,2-azacylolidine was changed to 15.3 mg/min. It was polymerized using the method.

The polymerization prescription, physical properties, and characteristics of the obtained random copolymer 11 are shown in Table 3.

[Preparation Example 12 (Production of Random Copolymer 12)]

Polymerization conditions other than the amount of hydrogen addition were the same as in [Preparation Example 1] above, and random copolymer 12 was obtained.

The polymerization prescription, physical properties, and characteristics of the obtained random copolymer 12 are shown in Table 3.

[Preparation Example 13 (Production of Random Copolymer 13)]

Polymerization conditions other than the amount of hydrogen addition were the same as in [Preparation Example 1] above, and random copolymer 13 was obtained.

The polymerization prescription, physical properties, and characteristics of the obtained random copolymer 13 are shown in Table 3.

[Preparation Example 14 (Production of Random Copolymer 14)]

The addition rate of n-butyllithium, a polymerization initiator, was set to 13.2 mg/min, the addition rate of 2,2-di(2-tetrahydrofuryl)propane, a polar substance, was set to 0.11 mg/min, and the modifier, 2,2 Random copolymer 1 of [Preparation Example 1] above except that the addition rate of -dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azacylolidine was changed to 13.4 mg/min. Polymerization was performed in the same manner as above.

The polymerization prescription, physical properties, and characteristics of the obtained random copolymer 14 are shown in Table 3.

[Production Example 15 (Production of Random Copolymer 15)]

The addition rate of n-butyllithium, a polymerization initiator, was changed to 10.2 mg/min, the addition rate of 2,2-di(2-tetrahydrofuryl)propane, a polar substance, was changed to 0.07 mg/min, and no denaturant was added. Except for this, polymerization was carried out in the same manner as random copolymer 1 of [Preparation Example 1] above.

The polymerization prescription, physical properties, and characteristics of the obtained random copolymer 15 are shown in Table 3.

[Production Example 16 (Production of Random Copolymer 16)]

The internal volume is 10L, the ratio (L/D) of the internal height (L) and diameter (D) is 4.0, it has an inlet at the bottom and an outlet at the top, and has a stirrer, which is a formative reactor with a stirrer, and a jacket for temperature control. Two molded pressure vessels were connected as polymerization reactors.

1,3-butadiene, from which water was previously removed, was mixed at a rate of 22.0 g/min, styrene at 3.9 g/min, and n-hexane at 175.0 g/min. In a static mixer provided in the middle of the pipe supplying this mixed solution to the inlet of the reactor, n-butyllithium for inactivating residual impurities was added and mixed at 6.0 mg/min, and then continuously supplied to the bottom of the reactor. In addition, 2,2-di(2-tetrahydrofuryl)propane as a polar substance was vigorously mixed with a stirrer at a rate of 0.34 mg/min and n-butyllithium as a polymerization initiator at a rate of 23.8 mg/min. The first reactor was supplied to the bottom of the reactor, and the temperature inside the reactor was maintained at 67°C.

The polymer solution was continuously withdrawn from the top of the first reactor and continuously supplied to the bottom of the second reactor to continue the reaction at 70°C, and was further supplied to the static mixer from the top of the second reactor. In a static mixer, 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azacylolidine is added as a denaturant at a rate of 24.2 mg/min to denature the growing ends. did.

The obtained polymerization solution was crumbled under the crumbling conditions described above to obtain crumbs of random copolymer 16. The crumb was separated by particle size using a metal mesh sieve, and D50 was calculated by measuring the weight fraction for each particle size. After calculating the D50 of the crumb, an analysis sample of random copolymer 16 was obtained by drying the crumb in a vacuum dryer heated to 90°C for 2 hours.

The polymerization prescription, physical properties, and characteristics of random copolymer 16 are shown in Table 4.

[Production Example 17 (Production of Random Copolymer 17)]

The internal volume is 10 L, the ratio (L/D) of the internal height (L) and diameter (D) is 3.0, it has an inlet at the bottom and an outlet at the top, and has a stirrer that is a form reactor with a stirrer and a jacket for temperature control. Two molded pressure vessels were connected as polymerization reactors.

1,3-butadiene, from which water was previously removed, was mixed at a rate of 22.0 g/min, styrene at 3.9 g/min, and n-hexane at 175.0 g/min. In a static mixer provided in the middle of the pipe supplying this mixed solution to the inlet of the reactor, n-butyllithium for inactivating residual impurities was added and mixed at 6.0 mg/min, and then continuously supplied to the bottom of the reactor. In addition, 2,2-di(2-tetrahydrofuryl)propane as a polar substance was vigorously mixed with a stirrer at a rate of 0.24 mg/min and n-butyllithium as a polymerization initiator at a rate of 25.2 mg/min. The first reactor was supplied to the bottom of the reactor, and the temperature inside the reactor was maintained at 67°C.

The polymer solution was continuously withdrawn from the top of the first reactor and continuously supplied to the bottom of the second reactor to continue the reaction at 70°C, and was further supplied to the static mixer from the top of the second reactor. In a static mixer, 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azacylolidine is added as a denaturant at a rate of 25.6 mg/min to denature the growing ends. did.

Next, the polymerization solution was placed in a pressure vessel having an internal volume of 20 L, a stirrer having an internal height (L) and diameter (D) ratio (L/D) of 4.0, and a pressure vessel having a stirrer and a jacket for temperature control. 10L was transferred, the internal temperature was set to 80°C, and hydrogen was introduced into the system.

Next, 60 ppm of a hydrogenation catalyst was added based on titanium relative to the amount of input monomer, and the hydrogenation reaction was performed at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C. After reaching the predetermined integrated hydrogen flow rate, the reaction liquid was returned to normal temperature and normal pressure and extracted from the reaction vessel to obtain a polymer solution.

The obtained polymer solution was crumbled under the crumbling conditions described above to obtain crumbs of random copolymer 17. The crumb was separated by particle size using a metal mesh sieve, and D50 was calculated by measuring the weight fraction for each particle size. After calculating the crumb D50, the crumb was dried in a vacuum dryer heated to 90°C for 2 hours to obtain an analysis sample of random copolymer 17.

The polymerization recipe, physical properties, and characteristics of random copolymer 17 are shown in Table 4.

[Production Example 18 (Production of Random Copolymer 18)]

In an autoclave reactor with an internal volume of 40 L and a ratio (L/D) of internal height (L) and diameter (D) of 4.0, 25800 g of normal hexane and the polar substance 2,2-di(2-tetrahydrofuryl) were added. 3.1g of propane, 645g of styrene, and 2814g of 1,3-butadiene were added. After adjusting the temperature of the reactor contents to 40°C, polymerization was initiated by adding a cyclohexane solution containing 2.9 g of n-butyllithium and carried out under adiabatic conditions.

When the polymerization conversion rate reached 99%, 840 g of additional butadiene was added and polymerization was performed for an additional 5 minutes to obtain a reaction liquid containing the polymer. Then, 2.9 g of 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azacylolidine was added as a denaturant, and reacted at the active site of the polymer for 30 minutes.

Next, the reaction solution was brought to 80°C and hydrogen was introduced into the system.

Next, 60 ppm of a hydrogenation catalyst was added based on titanium relative to the amount of input monomer, and the hydrogenation reaction was performed at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C. After reaching the predetermined integrated hydrogen flow rate, the reaction liquid was returned to normal temperature and normal pressure and extracted from the reaction vessel to obtain a polymer solution.

The obtained polymerization solution was crumbled under the crumbling conditions described above to obtain crumbs of random copolymer 18. The crumb was separated by particle size using a metal mesh sieve, and D50 was calculated by measuring the weight fraction for each particle size. After calculating the D50 of the crumb, an analysis sample of random copolymer 18 was obtained by drying the crumb in a vacuum dryer heated to 90°C for 2 hours.

The polymerization recipe, physical properties, and characteristics of random copolymer 18 are shown in Table 5.

[Production Example 19 (Production of Random Copolymer 19)]

Polymerization conditions other than the amount of hydrogen addition were the same as in [Production Example 17] above, and random copolymer 19 was obtained.

The polymerization prescription, physical properties, and characteristics of the obtained random copolymer 19 are shown in Table 4.

[Production Example 20 (Production of Random Copolymer 20)]

Polymerization conditions other than the amount of hydrogen addition were the same as in [Production Example 18] above to obtain random copolymer 20.

The polymerization prescription, physical properties, and characteristics of the obtained random copolymer 20 are shown in Table 5.

[Production Example 21 (Production of Random Copolymer 21)]

The denaturant was changed to N,N-bis(triethoxysilylpropyl)aminopropyl-1-imidazole, and other conditions were the same as [Preparation Example 17] above to obtain random copolymer 21.

The polymerization prescription, physical properties, and characteristics of the obtained random copolymer 21 are shown in Table 4.

[Production Example 22 (Production of Random Copolymer 22)]

The internal volume is 10 L, the ratio (L/D) of the internal height (L) and diameter (D) is 7.0, it has an inlet at the bottom and an outlet at the top, and has a stirrer that is a form reactor with a stirrer and a jacket for temperature control. Two molded pressure vessels were connected as polymerization reactors.

1,3-butadiene, from which water was previously removed, was mixed at a rate of 21.0 g/min, styrene at 5.2 g/min, and n-hexane at 175.0 g/min.

In a static mixer provided in the middle of the pipe supplying this mixed solution to the inlet of the reactor, n-butyllithium for inactivating residual impurities was added and mixed at 6.0 mg/min, and then continuously supplied to the bottom of the reactor.

In addition, 2,2-di(2-tetrahydrofuryl)propane as a polar substance was vigorously mixed with a stirrer at a rate of 1.20 mg/min and n-butyllithium as a polymerization initiator at a rate of 23.8 mg/min. The first reactor was supplied to the bottom of the reactor, and the temperature inside the reactor was maintained at 67°C.

The polymer solution was continuously withdrawn from the top of the first reactor and continuously supplied to the bottom of the second reactor to continue the reaction at 70°C, and was further supplied to the static mixer from the top of the second reactor. In a static mixer, 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azacylolidine is added as a denaturant at a rate of 24.2 mg/min to denature the growing ends. did.

Next, the polymer solution was placed in a pressure vessel having an internal volume of 20 L, a stirrer having an internal height (L) and diameter (D) ratio (L/D) of 4.0, which is a reactor having a stirrer, and a jacket for temperature control. 10L was transferred, the internal temperature was set to 80°C, and hydrogen was introduced into the system.

Next, 60 ppm of hydrogenation catalyst was added based on titanium with respect to the amount of input monomer, and hydrogenation reaction was carried out at a hydrogen pressure of 0.8 MPa and an average temperature of 85°C. After reaching the predetermined integrated hydrogen flow rate, the reaction liquid was returned to normal temperature and normal pressure and extracted from the reaction vessel to obtain a polymer solution.

The obtained polymer solution was crumbled under the crumbling conditions described above to obtain crumbs of random copolymer 22.

The crumb was separated by particle size using a metal mesh sieve, and D50 was calculated by measuring the weight fraction for each particle size. After calculating the D50 of the crumb, an analysis sample of random copolymer 22 was obtained by drying the crumb in a vacuum dryer heated to 90°C for 2 hours.

The polymerization prescription, physical properties, and characteristics of the obtained random copolymer 22 are shown in Table 3.

Using random copolymers 1 to 15 and 22 of Preparation Examples 1 to 15 and 22 described above, veils for evaluating product water content (VM) of [Examples 1 to 15 and 16] were manufactured.

Similarly, using the random copolymers 16 to 21 of Preparation Examples 16 to 21 described above, veils for evaluating product moisture content (VM) of [Comparative Examples 1 to 6] were manufactured.

The manufacturing method of the veil for VM evaluation is shown below.

<Manufacture of veil for VM evaluation>

300 g of each hydrated crumb obtained in Preparation Examples 1 to 22 was used to manufacture a veil for VM evaluation.

The random copolymer crumb was dehydrated by passing it 10 times through a 6-inch roll heated to 80°C with a clearance set at 2 mm. The dehydrated crumb was then dried by passing it 15 times through 6 inch rolls heated to 110°C.

In a rectangular container with dimensions of 42 mm on the long side, 21 mm on the short side, and 40 mm in depth, 35 g of crumb prepared by the above method is heated to 60 ° C, then filled, and compressed by applying a pressure of 3.5 MPa for 10 seconds in a cylinder. Got a veil for VM evaluation.

<Evaluation>

Next, as an evaluation of Examples 1 to 16 and Comparative Examples 1 to 6, the dehydration efficiency was evaluated in terms of product moisture content (VM).

The evaluation method of VM is described below.

10 g of veil for VM evaluation was placed in a halogen heater heated to 110°C and heated for 20 minutes.

From the change in mass after heating, the moisture content (VM) in the sample was calculated.

The calculation formula for VM is as follows.

VM (weight%) = (sample mass before heating - sample mass after heating) / sample mass before heating × 100

From the viewpoint of preventing water vaporization and pressure increase in the kneader when processing a rubber composition using a random copolymer into a tire product, it was judged that VM of 0.75% by weight or less was good for practical use.

VMs in Examples 1 to 16 and Comparative Examples 1 to 6 are shown in Tables 6 to 9.

From Tables 6 to 9, it became clear that the VM of the veil using the random copolymer of the examples was improved.

The random copolymer of this embodiment has the potential for industrial use in fields such as tire members, automobile interior and exterior products, anti-vibration rubber, belts, shoes, foam, and various industrial products.

Claims (6)

It has an aromatic vinyl monomer unit, a conjugated diene monomer unit, and an ethylene structure,
The molecular weight distribution by GPC is unimodal,
having a molecular weight distribution of 1.30 to 1.75,
Random copolymer. The method of claim 1, wherein the iodine number is 14 or more and 200 or less,
Random copolymer. The method of claim 1 or 2, wherein the weight average molecular weight is 300,000 to 800,000.
Random copolymer. The method of claim 1 or 2, wherein the glass transition temperature is -70°C or more and -50°C or less,
Random copolymer. A method for producing crumbs of the random copolymer according to claim 1 or 2,
A process of polymerizing an aromatic vinyl compound and a conjugated diene compound in solution;
Process of obtaining crumb by desolvating from a solution containing a polymer
With
The median diameter (D50) of the crumb is 6.0 mm or more and 12.0 mm or less,
How to make crumbs. The random copolymer according to claim 1 or 2,
Rubber components other than the above random copolymer,
Plasticizer ingredients,
filler ingredients
Including pneumatic tires.