JP2011006543A - Modified conjugated diene-aromatic vinyl copolymer, method for producing the same, and copolymer composition thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a modified conjugated diene-aromatic vinyl copolymer having excellent balance between low hysteresis loss and wet skid resistance when made into a vulcanizate including an inorganic filler and also satisfying practically sufficient abrasion resistance and fracture strength, a method for producing the same, and a modified conjugated diene-aromatic vinyl copolymer composition thereof.SOLUTION: The modified conjugated diene-aromatic vinyl copolymer comprises a conjugated diene compound and an aromatic vinyl compound. The bonding amount of the conjugated diene is 50-85 mass% and the bonding amount of the aromatic vinyl is 15-50 mass% in the copolymer. The copolymer has a functional group including a silyl group substituted with one or more alkoxy groups and one or more nitrogen atoms at one end of the polymer chain and a polymer block whose bonding amount of the conjugated diene is higher than the average composition of the copolymer and whose weight-average molecular weight in terms of polystyrene obtained from gel permeation chromatography (GPC) is 2,000-50,000 at the other end of the polymer chain.

Description

The present invention relates to a modified conjugated diene-aromatic vinyl copolymer, a process for producing the same, and a composition containing the copolymer.
Specifically, the polymer chain has a silyl group substituted with one or more alkoxy groups at one end of the polymer chain and a functional group containing one or more nitrogen atoms, and is co-polymerized at the other end of the polymer chain. The present invention relates to a modified conjugated diene-aromatic vinyl copolymer having a polymer block having a larger amount of conjugated diene bonds than the average composition of the polymer, a method for producing the same, and a composition containing the copolymer.

In recent years, environmental considerations such as the suppression of carbon dioxide emissions have become social demands. Specifically, demands for reducing fuel consumption for automobiles are increasing. Under such circumstances, there has been a demand for the development of a material having low rolling resistance as a material for automobile tires, particularly tire treads in contact with the ground. On the other hand, from the viewpoint of safety, development of materials having excellent wet skid resistance and practically sufficient wear resistance and fracture characteristics is required.
Conventionally, carbon black, silica, and the like have been used as reinforcing fillers for tire treads. Use of silica has an advantage that low hysteresis loss and wet skid resistance can be improved. However, on the other hand, the hydrophilic surface of silica has a disadvantage that its affinity with conjugated diene rubber is low and its dispersibility is poor compared to carbon black. Therefore, in order to improve the dispersibility or to provide a bond between silica and rubber, it is necessary to contain a silane coupling agent or the like separately.
Furthermore, in recent years, the dispersibility of silica in rubber materials has been improved by introducing functional groups having affinity and reactivity with silica at the end of rubber molecules having high mobility. Attempts have been made to reduce hysteresis loss by sealing the part with a bond with silica particles. For example, Patent Document 1 discloses a modified diene rubber obtained by reacting a polymer terminus with a modifier having a glycidylamino group. Patent Document 2 discloses that a glycidoxyalkoxysilane is reacted with a polymer terminal. The resulting modified diene rubber is disclosed. Further, Patent Documents 3 and 4 propose a modified diene rubber obtained by reacting an alkoxysilane containing an amino group with a polymer terminal, and a composition of these with silica.

International Publication No. 01/23467 Pamphlet Japanese Patent Application Laid-Open No. 07-233217 JP 2001-158834 A JP 2003-171418 A

However, with the further increase in demand for fuel efficiency in recent years, development of a rubber composition having further reduced hysteresis loss has been required.
In view of the above circumstances, the present invention has an excellent balance between low hysteresis loss and wet skid resistance when a vulcanized product containing an inorganic filler, and satisfies practically sufficient wear resistance and fracture strength. An object of the present invention is to provide a modified conjugated diene-aromatic vinyl copolymer, a production method thereof, and a modified conjugated diene-aromatic vinyl copolymer composition.

  As a result of diligent research and studies to solve the above problems, the present inventors have adjusted the conjugated diene bond amount and the aromatic vinyl bond amount to a specific range, and one or more alkoxy groups on one end of the polymer chain. A polymer block having a silyl group substituted with a group and a functional group containing one or more nitrogen atoms, and having a higher amount of conjugated diene bonds than the average composition of the copolymer at the other end of the polymer chain A modified conjugated diene-aromatic vinyl copolymer having a polymer block having a weight average molecular weight adjusted to a specific range, an inorganic filler, particularly a silica-based inorganic filler, and a vulcanized product; In this case, it was found that the balance between low hysteresis loss and wet skid resistance was excellent, and that practically sufficient wear resistance and fracture strength were satisfied, and the present invention was completed.

That is, the present invention is as follows.
[1]
A copolymer comprising a conjugated diene compound and an aromatic vinyl compound,
The conjugated diene bond amount of the copolymer is 50 to 85% by mass, the aromatic vinyl bond amount is 15 to 50% by mass,
A functional group containing one or more nitrogen atoms and a silyl group substituted with one or more alkoxy groups at one end of the polymer chain;
A polymer block having a higher amount of conjugated diene bonds than the average composition of the copolymer at the other end of the polymer chain, and having a weight average molecular weight in terms of polystyrene determined by gel permeation chromatography of 2,000- Having 50,000 polymer blocks,
Modified conjugated diene-aromatic vinyl copolymer.
[2]
The modification according to [1] above, wherein the amount of conjugated diene bonds in the polymer block having a larger amount of conjugated diene bonds than the average composition of the copolymer is 95% by mass or more and the amount of aromatic vinyl bonds is 5% by mass or less. Conjugated diene-aromatic vinyl copolymer.
[3]
The modified conjugate according to [1] or [2] above, wherein the vinyl bond content in the conjugated diene bond unit in the polymer block having a higher conjugated diene bond content than the average composition of the copolymer is 5 to 25 mol%. Diene-aromatic vinyl copolymer.
[4]
The terminal functional part of the modified conjugated diene-aromatic vinyl copolymer has the following formula (1)

(In Formula (1), Polym is a copolymer chain, R ¹ and R ² are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group, and R ³ is 1 to 20 carbon atoms. R ⁴ and R ⁵ are hydrocarbon groups having 1 to 6 carbon atoms which may be the same or different, and form a ring structure of 5 or more members with two adjacent Ns, R ⁶ is a hydrocarbon group having 1 to 20 carbon atoms, or a 3 organic substituted silyl group, and m and n are 1 or 2 and m + n is an integer that is 3 or less.)
Or the following formula (2)

(In the formula (2), Polym, R ^{1 to} R ⁶ , m, and n have the same meanings as the formula (1), and R ⁷ is a hydrocarbon group having 1 to 20 carbon atoms, or a 3 organic substituted silyl group. is there.)
The modified conjugated diene-aromatic vinyl copolymer according to any one of the above [1] to [3], which is represented by:
[5]
A method for producing a modified conjugated diene-aromatic vinyl copolymer according to any one of [1] to [4] above,
A polymer block in which an alkali metal compound or an alkaline earth metal compound is used as a polymerization initiator, a conjugated diene compound is mainly polymerized as a first step, and the amount of conjugated diene bonds is larger than the average composition of the copolymer. After forming a polymer block having a weight average molecular weight of 2,000 to 50,000 in terms of polystyrene, a conjugated diene having an active end is obtained by randomly copolymerizing a conjugated diene compound and an aromatic vinyl compound as the second step. A polymerization step for obtaining an aromatic vinyl copolymer;
A modification step of reacting a compound having one or more nitrogen atoms with a silyl group substituted with two or more alkoxy groups at the active end of the conjugated diene-aromatic vinyl copolymer;
A process for producing a modified conjugated diene-aromatic vinyl copolymer.
[6]
The first block of the polymerization process is carried out in the state where only the conjugated diene compound is present as a monomer, and the polymer block has a conjugated diene bond amount larger than the average composition of the copolymer, and is a weight average in terms of polystyrene After forming a polymer block having a molecular weight of 2,000 to 50,000, the second stage copolymerization reaction is carried out by adding both an aromatic vinyl compound or an aromatic vinyl compound and a conjugated diene compound into the polymerization system. The manufacturing method of the modified conjugated diene-aromatic vinyl copolymer of the said [5] implementation to implement.
[7]
The method for producing a modified conjugated diene-aromatic vinyl copolymer according to the above [6], which comprises a step of adding a polar compound when carrying out the second-stage copolymerization reaction.
[8]
A polymer block in which the first step of the polymerization process is carried out in the presence of a conjugated diene compound and an aromatic vinyl compound as monomers, and the amount of conjugated diene bonds is larger than the average composition of the copolymer, and is converted to polystyrene The modified conjugated diene according to the above [5], wherein a second-stage copolymerization reaction is carried out by adding a polar compound after forming a polymer block having a weight average molecular weight of 2,000 to 50,000. A method for producing an aromatic vinyl copolymer.
[9]
The compound having a silyl group substituted with two or more alkoxy groups and one or more nitrogen atoms is represented by the following formula (3):

(In the formula ^{(3), R 1, R} 2 are each independently an alkyl group having 1 to 20 carbon atoms, or an aryl group, R ³ is an alkylene group having 1 to 20 carbon atoms, R ^4, R ⁵ is a hydrocarbon group having 1 to 6 carbon atoms which may be the same or different, and forms a ring structure of 5 or more members with two adjacent Ns, and R ⁶ has 1 to 20 carbon atoms (It is a hydrocarbon group or a 3 organic substituted silyl group, and p is an integer of 2 or 3.)
Or the following formula (4)

(In Formula (4), R < ¹ > -R < ⁶ >, p is synonymous with said Formula (3), and R < ⁷ > is a C1-C20 hydrocarbon group or a 3 organic substituted silyl group.)
The manufacturing method of the modified conjugated diene-aromatic vinyl copolymer in any one of said [5]-[8] represented by these.
[10]
Silica-based inorganic filler 0.5 to 300 parts by mass with respect to 100 parts by mass of the rubber component containing 20 parts by mass or more of the modified conjugated diene-aromatic vinyl copolymer according to any one of [1] to [4] above. A modified conjugated diene-aromatic vinyl copolymer composition comprising:

  According to the present invention, when a vulcanizate containing an inorganic filler is used, the modified conjugate has an excellent balance between low hysteresis loss and wet skid resistance, and also satisfies practically sufficient wear resistance and fracture strength. Diene-aromatic vinyl copolymers, methods for their production, and modified conjugated diene-aromatic vinyl copolymer compositions are provided.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. This invention is not limited to the form shown below.

The modified conjugated diene-aromatic vinyl copolymer of this embodiment is
A copolymer comprising a conjugated diene compound and an aromatic vinyl compound,
The conjugated diene bond amount of the copolymer is 50 to 85% by mass, the aromatic vinyl bond amount is 15 to 50% by mass,
A functional group containing one or more nitrogen atoms and a silyl group substituted with one or more alkoxy groups at one end of the polymer chain;
A polymer block having a higher amount of conjugated diene bonds than the average composition of the copolymer at the other end of the polymer chain, and having a weight average molecular weight in terms of polystyrene determined by gel permeation chromatography of 2,000- It has 50,000 polymer blocks.

  The amount of conjugated diene bonds in the modified conjugated diene-aromatic vinyl copolymer of the present embodiment is 50 to 85% by mass, and preferably 60 to 80% by mass. Moreover, the amount of aromatic vinyl bonds is 15-50 mass%, and it is preferable that it is 20-40 mass%. When the conjugated diene bond amount and the aromatic vinyl bond amount are in the above ranges, a vulcanizate having an excellent balance between low hysteresis loss and wet skid resistance and satisfying wear resistance and fracture strength can be obtained.

  Here, the amount of aromatic vinyl bonds can be measured by ultraviolet absorption of a phenyl group. Specifically, it can measure by the method according to the Example mentioned later.

  Moreover, it is preferable that the vinyl bond amount in a conjugated diene bond unit is 30-75 mol%, and it is more preferable that it is 35-65 mol%. When the vinyl bond amount is in the above range, a vulcanizate having an excellent balance between low hysteresis loss and wet skid resistance and satisfying wear resistance and fracture strength can be obtained.

  Here, when the modified conjugated diene-aromatic vinyl copolymer is a copolymer of butadiene and styrene, the vinyl bond amount is determined by the method of Hampton (RR Hampton, Analytical Chemistry, 21, 923 (1949). )), The vinyl bond amount (1,2-bond amount) in the butadiene bond unit can be determined.

  Low hysteresis loss and wet skid resistance when the microstructure (each bond amount in the copolymer) is in the above range and the glass transition temperature of the copolymer is in the range of −45 to −15 ° C. Due to this balance, a further excellent vulcanizate can be obtained.

  Regarding the glass transition temperature, in accordance with ISO 22768: 2006, a DSC curve is recorded while raising the temperature in a predetermined temperature range, and the peak top (Inflection point) of the DSC differential curve is defined as the glass transition temperature.

  The modified conjugated diene-aromatic vinyl copolymer of this embodiment has a silyl group substituted with one or more alkoxy groups at one terminal portion thereof and a functional group containing one or more nitrogen atoms. The silyl group substituted with one or more alkoxy groups and the functional group containing one or more nitrogen atoms may be bonded to either the polymerization initiation terminal or the polymerization termination terminal. It is preferable that it is bonded to the terminal.

  Further, from the viewpoint of affinity with inorganic fillers such as silica and carbon black, the structure is represented by the following formula (1).

(In Formula (1), Polym is a copolymer chain, R ¹ and R ² are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group, and R ³ is 1 to 20 carbon atoms. R ⁴ and R ⁵ are hydrocarbon groups having 1 to 6 carbon atoms which may be the same or different, and form a ring structure of 5 or more members with two adjacent Ns, R ⁶ is a hydrocarbon group having 1 to 20 carbon atoms, or a 3 organic substituted silyl group, and m and n are 1 or 2 and m + n is an integer that is 3 or less.)
Or the following formula (2)

(In the formula (2), Polym, R ^{1 to} R ⁶ , m, and n have the same meanings as the formula (1), and R ⁷ is a hydrocarbon group having 1 to 20 carbon atoms, or a 3 organic substituted silyl group. is there.)
It is preferable that it is a structure represented by these.

  In the modified conjugated diene-aromatic vinyl copolymer of the present embodiment, the amount of conjugated diene bonded to the end of the polymer chain opposite to the end to which the functional group is bonded is more than the average composition of the copolymer. It has a polymer block with many. The polymer block preferably has a conjugated diene bond content of 95% by mass or more and an aromatic vinyl bond content of 5% by mass or less, more preferably a conjugated diene bond content of 97% by mass or more and an aromatic vinyl bond. The amount is 3% by mass or less. By having a polymer block with a larger amount of conjugated diene bonds than the average composition of the copolymer at the end, a site to be preferentially vulcanized is formed at the end of the polymer chain. Sometimes hysteresis loss is low. Moreover, since the reaction between the silane coupling agent and the polymer double bond portion described later takes place preferentially, it is considered that the hysteresis loss is reduced. From the above viewpoint, the polymer block is particularly preferably a conjugated diene homopolymer block.

  The vinyl bond amount in the conjugated diene bond unit in the polymer block having a higher conjugated diene bond amount than the average composition of the copolymer is preferably 5 to 25 mol%, more preferably 7 to 20 mol%. preferable. The lower limit (5 mol%) of the vinyl bond amount in the conjugated diene bond unit is determined by the lower limit value of the vinyl bond generation amount in anionic polymerization, and the upper limit is preferably 25 mol% or less from the viewpoint of vulcanization characteristics.

  The weight average molecular weight of the polymer block having a conjugated diene bond amount higher than the average composition of the copolymer is 2,000 to 50,000 in terms of polystyrene calculated by gel permeation chromatography (GPC), and is 5,000. It is preferable that it is -20,000. The weight average molecular weight of the polymer block is 2,000 or more from the viewpoint of forming a vulcanization site with a sufficient probability, and 50 from the viewpoint of preventing the polymer block from clearly phase-separating in the copolymer. , 000 or less.

  The molecular weight of the entire copolymer is preferably in the range of 200,000 to 2,000,000, more preferably in the range of 300,000 to 1,000,000 in terms of polystyrene-equivalent weight average molecular weight. The weight average molecular weight of the entire copolymer is preferably 200,000 or more from the viewpoint of obtaining sufficient physical properties such as low hysteresis loss, wear resistance, and fracture resistance, and 2,000,000 from the viewpoint of workability. 000 or less is preferable.

  The method for producing the modified conjugated diene-aromatic vinyl copolymer of the present embodiment is not particularly limited, but polymerization of the conjugated diene compound and the aromatic vinyl compound with an alkali metal compound or an alkaline earth metal compound is started in an organic solvent. It can be produced by anionic polymerization as an agent.

  The modified conjugated diene-aromatic vinyl copolymer of this embodiment uses, for example, an alkali metal compound or an alkaline earth metal compound as a polymerization initiator, and mainly polymerizes a conjugated diene compound as a first step, After forming a polymer block having a conjugated diene bond amount higher than the average composition of the polymer and having a polystyrene-equivalent weight average molecular weight of 2,000 to 50,000, a conjugated diene compound and A polymerization process for obtaining a conjugated diene-aromatic vinyl copolymer having an active end by randomly copolymerizing an aromatic vinyl compound, and at least two active ends of the conjugated diene-aromatic vinyl copolymer. And a modification step of reacting a compound having one or more nitrogen atoms with a silyl group substituted with an alkoxy group.

  As the alkali metal compound, an organic lithium compound is particularly suitable. The organolithium compound includes a low molecular weight compound, a solubilized oligomeric organolithium compound, a compound composed of a carbon-lithium bond in a bonding mode between an organic group and lithium, a compound composed of a nitrogen-lithium bond, and a tin-lithium bond. Compounds and the like.

  Specific examples include n-butyl lithium, sec-butyl lithium, tert-butyl lithium, n-hexyl lithium, benzyl lithium, phenyl lithium, stilbene lithium, and the like. Examples of the compound comprising a nitrogen-lithium bond include lithium dimethylamide, lithium diethylamide, lithium dipropylamide, lithium di-n-hexylamide, lithium diisopropylamide, lithium hexamethyleneimide, lithium pyrrolidide, lithium piperidide, lithium Examples include heptamethylene imide and lithium morpholide.

  In addition to the above monoorganolithium compound, a polyfunctional organolithium compound can be used in combination for polymerization. Examples of polyfunctional organolithium compounds include 1,4-dilithiobutane, a reaction product of sec-butyllithium and diisopropenylbenzene, 1,3,5-trilithiobenzene, n-butyllithium, 1,3-butadiene, and divinylbenzene. And a reaction product of n-butyllithium and a polyacetylene compound. Furthermore, organic alkali metal compounds disclosed in US Pat. No. 5,708,092, British Patent 2,241,239, US Pat. No. 5,527,753, etc. are also used. be able to.

Particularly preferred as the organic lithium compound are n-butyllithium and sec-butyllithium from the viewpoints of industrial availability and ease of control of the polymerization reaction.
These organolithium compounds may be used as a mixture of not only one type but also two or more types.

  Examples of other organic alkali metal compounds include organic sodium compounds, organic potassium compounds, organic rubidium compounds, and organic cesium compounds. Specific examples thereof include sodium naphthalene and potassium naphthalene. In addition, lithium, sodium, potassium alkoxide, sulfonate, carbonate, amide and the like may be used. Moreover, you may use together with another organometallic compound.

  On the other hand, examples of the alkaline earth metal compound include organic magnesium compounds, organic calcium compounds, and organic strontium compounds. Specific examples include dibutyl magnesium, ethyl butyl magnesium, propyl butyl magnesium, and the like. Further, alkaline earth metal alkoxides, sulfonates, carbonates, amides and other compounds may be used. These organic alkaline earth metal compounds may be used in combination with alkali metal compounds or other organic metal compounds.

  In the present embodiment, the conjugated diene-aromatic vinyl copolymer is preferably obtained by polymerizing the above-described alkali metal compound and / or alkaline earth metal compound as a polymerization initiator and growing by an anionic polymerization reaction. In particular, a polymer having an active end obtained by a growth reaction by living anionic polymerization is preferable. Although it does not specifically limit as a polymerization mode, It can carry out by superposition | polymerization modes, such as a batch type, or the continuous type in a 2 or more connected reactor.

  The conjugated diene compound is not particularly limited, and examples thereof include 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1 , 3-heptadiene, 1,3-hexadiene and the like. These may be used alone or in combination of two or more. Among these, 1,3-butadiene and isoprene are particularly preferable from the viewpoint of industrial availability.

  If allenes or acetylenes are contained as impurities in the conjugated diene compound, the modification reaction described later may be inhibited. Therefore, the total of these concentrations is preferably 200 ppm or less, and 100 ppm or less. More preferably, it is more preferably 50 ppm or less.

  The aromatic vinyl compound is not particularly limited, and examples thereof include styrene, p-methylstyrene, α-methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and diphenylethylene. These may be used alone or in combination of two or more. Among these, styrene is particularly preferable from the viewpoint of industrial availability.

  In the polymerization reaction of the conjugated diene compound-aromatic vinyl copolymer, for the purpose of randomly copolymerizing the aromatic vinyl compound with the conjugated diene compound, and as a vinylating agent for controlling the microstructure of the conjugated diene part, Furthermore, it is possible to add a small amount of a polar compound for the purpose of improving the polymerization rate.

  Examples of polar compounds include ethers such as tetrahydrofuran, diethyl ether, dioxane, ethylene glycol dimethyl ether, ethylene glycol dibutyl ether, diethylene glycol dimethyl ether, diethylene glycol dibutyl ether, dimethoxybenzene, and 2,2-bis (2-oxolanyl) propane; tetramethylethylenediamine , Tertiary amine compounds such as dipiperidinoethane, trimethylamine, triethylamine, pyridine, quinuclidine; alkali metal alkoxide compounds such as potassium tert-amylate, potassium tert-butylate, sodium tert-butylate, sodium amylate; A phosphine compound such as triphenylphosphine can be used. These polar compounds can be used alone or in combination of two or more.

  The amount of the polar compound used is selected according to the purpose and the degree of effect. Usually, 0.01-100 mol is preferable with respect to 1 mol of polymerization initiators. Such a polar compound (vinylating agent) can be used in an appropriate amount as a microstructure modifier for the polymer conjugated diene moiety depending on the desired amount of vinyl bonds. Many polar compounds have an effective randomizing effect in the copolymerization of conjugated diene compounds and aromatic vinyl compounds at the same time, and can be used as an adjustment of the distribution of aromatic vinyl compounds and as an adjuster of the amount of styrene block. . As a method for randomizing the conjugated diene compound and the aromatic vinyl compound, a part of 1,3-butadiene is intermittently produced during the copolymerization as described in JP-A-59-140221. You may use the method of adding.

  The polymerization temperature is not particularly limited as long as the living anion polymerization proceeds, but is preferably 0 ° C. or higher from the viewpoint of productivity, and a sufficient amount of the modifier to react with the active terminal after the polymerization is sufficiently secured. It is preferable that it is 120 degrees C or less from a viewpoint to do.

  In addition, from the viewpoint of preventing cold flow of the conjugated diene-aromatic vinyl copolymer, a polyfunctional aromatic vinyl compound such as divinylbenzene for controlling branching can also be used.

  As the solvent used for the polymerization, for example, hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons are used. Specifically, aliphatic hydrocarbons such as butane, pentane, hexane and heptane; alicyclic hydrocarbons such as cyclopentane, cyclohexane, methylcyclopentane and methylcyclohexane; aromatic hydrocarbons such as benzene, toluene and xylene; There may be mentioned hydrocarbons composed of mixtures thereof. In the conjugated diene compound, the aromatic vinyl compound, and the hydrocarbon solvent, each of the impurities or allenes or acetylenes is treated with an organometallic compound before being subjected to the polymerization reaction either individually or in a mixed solution. This is preferable because a polymer having a high concentration of active terminals tends to be obtained, and a high modification rate tends to be achieved.

  In the polymerization step of the modified conjugated diene-aromatic vinyl copolymer of the present embodiment, an alkali metal compound or an alkaline earth metal compound is used as a polymerization initiator, and a conjugated diene compound is mainly polymerized as a first step, After forming a polymer block having a conjugated diene bond amount larger than the average composition of the copolymer and having a weight average molecular weight of 2,000 to 50,000 in terms of polystyrene, a conjugated diene compound and an aromatic are used as the second step. A conjugated diene-aromatic vinyl copolymer can be obtained by randomly copolymerizing a vinyl compound. Here, “mainly” means that the ratio of the conjugated diene compound in all monomers to be polymerized is preferably 95% by mass or more, more preferably 97% by mass or more.

  As a first method for forming a polymer block having a larger amount of conjugated diene bonds than the average composition of the copolymer at the polymer end of the first step, the first step is performed in the state where only the conjugated diene compound is present. And a method of carrying out the polymerization reaction. Thereafter, an aromatic vinyl compound, or an aromatic vinyl compound and a conjugated diene compound are added to the polymerization system to advance the second stage copolymerization reaction. At this time, the conjugated diene compound present in the polymerization system at the time of the first stage polymerization reaction may be a part or all of the conjugated diene compound used in the entire polymerization process. When the whole amount of the conjugated diene compound is charged at the beginning of the polymerization, an aromatic vinyl compound is added after the polymerization reaction proceeds to form a conjugated diene polymer block having a polystyrene-equivalent weight average molecular weight of 2,000 to 50,000. Then, by copolymerizing with the conjugated diene compound remaining in the polymerization system, a copolymer in which a polymer block having a larger amount of conjugated diene bonds than the average composition of the copolymer is formed at the polymerization start end. Obtainable. When the conjugated diene compound added to the polymerization system at the beginning of the polymerization is a part of the conjugated diene compound used for the polymerization, a part of the conjugated diene compound existing in the system at the beginning of the polymerization, or substantially the entire amount. By adding the remaining conjugated diene compound and aromatic vinyl compound at the time of polymerization, a copolymer having a polymer block having a conjugated diene bond amount higher than the average composition of the copolymer at the polymerization start end is obtained. be able to. Among the above, first, a part of the conjugated diene compound is introduced into the polymerization system to start the polymerization, and after the polymerization is substantially completed, the remaining conjugated diene compound and aromatic vinyl compound are added to the system. A method of obtaining a copolymer by continuing the polymerization is particularly preferred from the viewpoint of easy control of the copolymer structure.

  In these methods, a polar compound can be added to the polymerization system in order to randomize the copolymer, control the microstructure, or accelerate the reaction. In this case, the method in which the polar compound is not added at the initial stage of the polymerization or only a small amount is added, and the necessary amount of the polar compound is added at the subsequent stage of polymerization is the vinyl bond in the conjugated diene bond unit in the block at the polymerization start end. A low amount of copolymer can be obtained, which is preferable.

  As a second method for forming a polymer block having a larger amount of conjugated diene bonds than the average composition of the copolymer at the end of the first stage, the total amount of each of the conjugated diene compound and the aromatic vinyl compound is Examples thereof include a method of mainly polymerizing a conjugated diene compound using an alkali metal compound or an alkaline earth metal compound as a polymerization initiator in the presence. After the polymerization proceeds to form a conjugated diene polymer block having a polystyrene-equivalent weight average molecular weight of 2,000 to 50,000, a polar compound is added to the second stage conjugated diene compound and the aromatic vinyl compound. Is copolymerized. In anionic polymerization in a non-polar solvent, the conjugated diene compound is selectively polymerized, so a polymer block with more conjugated diene bonds than the average copolymer composition is formed at the stage where no polar compound is added. By adding the polar compound, a polymer block in which the conjugated diene compound and the aromatic vinyl compound are copolymerized with good randomness is formed.

  When the polymerization process is carried out by these methods, a monomer, a polar substance, and a solvent are added in the second stage of the polymerization process, and since a trace amount of a polymerization reaction inhibiting substance is included in the polymerization process, the polymer A part of the polymerization active terminal is inactivated and the polymerization is terminated, whereby a small amount of a low molecular weight component is produced and remains in the finally obtained copolymer. When the molecular weight distribution of the modified conjugated diene-aromatic vinyl copolymer is measured by GPC having an RI detector and a UV detector observing the ultraviolet absorption of the phenyl group of the aromatic vinyl compound, the UV detected by the RI detector is UV. Since there is a low molecular weight component that is not detected by the detector or has a low detection intensity, the modified conjugated diene-aromatic vinyl copolymer of the present embodiment has a polymer having a larger amount of conjugated diene bonds than the average composition of the copolymer. You can confirm that the block exists.

  The copolymer block portion of the conjugated diene-aromatic vinyl copolymer of the present embodiment preferably has few or no blocks in which 30 or more aromatic vinyl units are chained. Specifically, when the copolymer is a butadiene-styrene copolymer, the method described in Kolthoff (method described in IM KOLTHOFF, et al., J. Polym. Sci. 1, 429 (1946)). In a known method for decomposing a polymer and analyzing the amount of polystyrene insoluble in methanol, a block in which 30 or more aromatic vinyl units are chained is preferably 5% by mass or less, more preferably based on the amount of polymer. 3% by mass or less.

  After obtaining a conjugated diene-aromatic vinyl copolymer having an active terminal by the method as described above, a compound having a silyl group substituted with two or more alkoxy groups and one or more nitrogen atoms (modifier) The modified conjugated diene-aromatic vinyl copolymer of the present embodiment can be obtained through a modification step in which the compound is reacted. As the modifier, the following formula (3)

(In the formula ^{(3), R 1, R} 2 are each independently an alkyl group having 1 to 20 carbon atoms, or an aryl group, R ³ is an alkylene group having 1 to 20 carbon atoms, R ^4, R ⁵ is a hydrocarbon group having 1 to 6 carbon atoms which may be the same or different, and forms a ring structure of 5 or more members with two adjacent Ns, and R ⁶ has 1 to 20 carbon atoms It is a hydrocarbon group or a 3 organic substituted silyl group, and p is an integer of 2 or 3.) or the following formula (4)

(In Formula (4), R < ¹ > -R < ⁶ >, p is synonymous with said Formula (3), and R < ⁷ > is a C1-C20 hydrocarbon group or a 3 organic substituted silyl group.)
And hydrocarbyloxysilane having a cyclic amino group containing two or more nitrogen atoms represented by the above, hydrocarbyloxysilane containing a functional group such as other cyclic amine, acyclic amine, imine, isocyanate, and cyclic azasilane It is done.

Specific examples of the hydrocarbyloxysilane having a cyclic amino group represented by the above formula (3) are shown below.
For example, 1- [3- (triethoxysilyl) propyl] -4-methylpiperazine, 1- [3- (diethoxyethylsilyl) propyl] -4-methylpiperazine, 1- [3- (trimethoxysilyl) propyl ] -3-methylimidazolidine, 1- [3- (diethoxyethylsilyl) propyl] -3-ethylimidazolidine, 1- [3- (triethoxysilyl) propyl] -3-methylhexahydropyrimidine, 1- [3- (dimethoxymethylsilyl) propyl] -3-methylhexahydropyrimidine, 3- [3- (tributoxysilyl) propyl] -1-methyl-1,2,3,4-tetrahydropyrimidine, 3- [3 -(Dimethoxymethylsilyl) propyl] -1-ethyl-1,2,3,4-tetrahydropyrimidine, 1- (2-ethoxyethyl) ) -3- [3- (trimethoxysilyl) propyl] imidazolidine, (2- {3- [3- (trimethoxysilyl) propyl] tetrahydropyrimidin-1-yl} ethyl) dimethylamine, 1- [3- (Triethoxysilyl) propyl] -4- (trimethylsilyl) piperazine, 1- [3- (dimethoxymethylsilyl) propyl] -4- (trimethylsilyl) piperazine, 1- [3- (tributoxysilyl) propyl] -4- (Trimethylsilyl) piperazine, 1- [3- (diethoxyethylsilyl) propyl] -3- (triethylsilyl) imidazolidine, 1- [3- (triethoxysilyl) propyl] -3- (trimethylsilyl) imidazolidine, 1 -[3- (Dimethoxymethylsilyl) propyl] -3- (trimethylsilyl) hexa Mud pyrimidine, 1- [3- (triethoxysilyl) propyl] -3- (trimethylsilyl) hexahydropyrimidine, 1- [4- (triethoxysilyl) butyl] -4- (trimethylsilyl) piperazine.

  Of these, 1- [3- (triethoxysilyl) propyl] -4-methylpiperazine, 1- [3- (tri Methoxysilyl) propyl] -3-methylimidazolidine, 1- [3- (triethoxysilyl) propyl] -3-methylhexahydropyrimidine, 1- [3- (triethoxysilyl) propyl] -4- (trimethylsilyl) Piperazine, 1- [3- (triethoxysilyl) propyl] -3- (trimethylsilyl) imidazolidine, 1- [3- (triethoxysilyl) propyl] -3- (trimethylsilyl) hexahydropyrimidine are preferred, and 1- [ 3- (Triethoxysilyl) propyl] -4-methylpiperazine, 1- [3- (triethoxysilyl) propyl] 4- (trimethylsilyl) piperazine is more preferable.

Specific examples of the hydrocarbyloxysilane having a cyclic amino group represented by the above formula (4) are shown below.
For example, 2- [3- (trimethoxysilyl) propyl] -1,3-dimethylimidazolidine, 2- (diethoxyethylsilyl) -1,3-diethylimidazolidine, 2- (triethoxysilyl) -1, 4-diethylpiperazine, 2- (dimethoxymethylsilyl) -1,4-dimethylpiperazine, 5- (triethoxysilyl) -1,3-dipropylhexahydropyrimidine, 5- (diethoxyethylsilyl) -1,3 -Diethylhexahydropyrimidine, {2- [3- (2-dimethylaminoethyl) -2- (ethyldimethoxysilyl) -imidazolidin-1-yl] -ethyl} -dimethylamine, 5- (trimethoxysilyl)- 1,3-bis- (2-methoxyethyl) -hexahydropyrimidine, 5- (ethyldimethoxysilyl) -1,3-bi -(2-trimethylsilylethyl) -hexahydropyrimidine) -1,3-dimethylimidazolidine, 2- (3-diethoxyethylsilyl-propyl) -1,3-diethylimidazolidine, 2- (3-triethoxy Silyl-propyl) -1,4-diethylpiperazine, 2- (3-dimethoxymethylsilyl-propyl) -1,4-dimethylpiperazine, 5- (3-triethoxysilyl-propyl) -1,3-dipropylhexa Hydropyrimidine, 5- (3-diethoxyethylsilyl-propyl) -1,3-diethylhexahydropyrimidine, {2- [3- (2-dimethylaminoethyl) -2- (3-ethyldimethoxysilyl-propyl) -Imidazolidin-1-yl] -ethyl} -dimethylamine, 5- (3-trimethoxysilyl-propi ) -1,3-bis- (2-methoxyethyl) -hexahydropyrimidine, 5- (3-ethyldimethoxysilyl-propyl) -1,3-bis- (2-trimethylsilylethyl) -hexahydropyrimidine, 2- [3- (Trimethoxysilyl) propyl] -1,3-bis (trimethylsilyl) imidazolidine, 2- (diethoxyethylsilyl) -1,3-bis (triethylsilyl) imidazolidine, 2- (triethoxysilyl) -1,4-bis (trimethylsilyl) piperazine, 2- (dimethoxymethylsilyl) -1,4-bis (trimethylsilyl) piperazine, 5- (triethoxysilyl) -1,3-bis (tripropylsilyl) hexahydropyrimidine Etc.

  Among these, 2- [3- (trimethoxysilyl) propyl] -1,3-dimethylimidazolidine, 2- [3 from the viewpoints of reactivity and interaction between the functional group and an inorganic filler such as silica. -(Trimethoxysilyl) propyl] -1,3- (bistrimethylsilyl) imidazolidine is preferred.

Specific examples of hydrocarbyloxysilane having a cyclic amino group other than the compounds represented by the formulas (3) and (4) are shown below.
For example, [3- (1-hexamethyleneimino) propyl] triethoxysilane, [3- (1-hexamethyleneimino) propyl] trimethoxysilane, [2- (1-hexamethyleneimino) ethyl] triethoxysilane, [2- (1-Hexamethyleneimino) ethyl] trimethoxysilane, [3- (1-pyrrolidinyl) propyl] triethoxysilane, [3- (1-pyrrolidinyl) propyl] trimethoxysilane, [3- (1- Heptamethyleneimino) propyl] triethoxysilane, [3- (1-dodecamethyleneimino) propyl] triethoxysilane, [3- (1-hexamethyleneimino) propyl] diethoxymethylsilane, [3- (1-hexa Methyleneimino) propyl] diethoxyethylsilane and the like.

Specific examples of hydrocarbyloxysilane having an acyclic amino group are shown below.
For example, [3- (dimethylamino) propyl] triethoxysilane, [3- (dimethylamino) propyl] trimethoxysilane, [3- (diethylamino) propyl] triethoxysilane, [3- (diethylamino) propyl] trimethoxy Silane, [2- (dimethylamino) ethyl] triethoxysilane, [2- (dimethylamino) ethyl] trimethoxysilane, [3- (dimethylamino) propyl] diethoxymethylsilane, [3-dibutylaminopropyl] tri Ethoxysilane, N, N-bis (trimethylsilyl) aminopropylmethyldimethoxysilane, N, N-bis (trimethylsilyl) aminopropyltrimethoxysilane, N, N-bis (trimethylsilyl) aminopropyltriethoxysilane, N, N-bis (Trimethylsil ) Aminopropylmethyldiethoxysilane, N, N-bis (trimethylsilyl) aminoethyltrimethoxysilane, N, N-bis (trimethylsilyl) aminoethyltriethoxysilane, N, N-bis (trimethylsilyl) aminoethylmethyldimethoxysilane and N, N-bis (trimethylsilyl) aminoethylmethyldiethoxysilane and the like can be mentioned.

Specific examples of hydrocarbyloxysilanes containing imino groups are shown below.
For example, N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine, N- (1-methylethylidene) -3- (triethoxysilyl) -1-propanamine, N -Ethylidene-3- (triethoxysilyl) -1-propanamine, N- (1-methylpropylidene) -3- (triethoxysilyl) -1-propanamine, N- (4-N, N-dimethylamino) Benzylidene) -3- (triethoxysilyl) -1-propanamine, N- (cyclohexylidene) -3- (triethoxysilyl) -1-propanamine, 1- [3- (triethoxysilyl) propyl]- 4,5-dihydroimidazole, 1- [3- (trimethoxysilyl) propyl] -4,5-dihydroimidazole, N- (3-triethoxysilylpro ) -4,5-dihydroimidazole, N- (3-isopropoxysilylpropyl) -4,5-dihydroimidazole, N- (3-methyldiethoxysilylpropyl) -4,5-dihydroimidazole and the like. .

Specific examples of the hydrocarbyloxysilane having an isocyanate group are shown below.
For example, 3-isocyanatopropyltrimethoxysilane, 3-isocyanatopropyltriethoxysilane, 3-isocyanatopropylmethyldiethoxysilane, 3-isocyanatopropyltriisopropoxysilane, tris (3-trimethoxysilylpropyl) isocyanate Examples include nurate.

Specific examples of the cyclic azasilane compound are shown below.
For example, Nn-butyl-aza-2,2-dimethoxysilacyclopentane, N-ethyl-aza-2,2-diethoxy-4-methylsilacyclopentane, N-allyl-aza-2,2-dimethoxysila Examples include cyclopentane and 1-trimethylsilyl-2,2-dimethoxy-1-aza-2-silacyclopentane.

Among the modifiers described above, the compound represented by the above formula (3) or formula (4) is preferable, and the compound represented by the above formula (3) is particularly preferable. When the compound represented by the above formula (3) is used as a modifier, a copolymer having excellent reactivity and interaction with inorganic fillers such as silica can be obtained, and low hysteresis loss tends to be achieved. It is in.
These modifiers may be used alone or in combination of two or more.

  The reaction temperature, reaction time, and the like when the above modifier is reacted with the polymerization active terminal are not particularly limited, but it is preferable to react at 0 ° C. or higher and 120 ° C. or lower for 30 seconds or longer.

  The modifier described above is such that the total number of moles of alkoxy groups bonded to silyl groups in the compound is 1 to 5 times the number of moles of alkali metal compound and / or alkaline earth metal compound added as a polymerization initiator. It is preferable to add in the range, more preferably in the range of 1.5 to 3 times, and still more preferably in the range of 1.5 to 2.5 times. The above numerical range is preferably at least 1 time from the viewpoint of obtaining a predetermined modification rate and leaving one or more alkoxy groups at the terminal end of the modified conjugated diene-aromatic vinyl copolymer molecular chain, From the viewpoint of cost, it is preferably 5 times or less.

  In order for the excellent effect of the present invention to be particularly exerted, the polymer having a functional group component is preferably 5% by mass or more, more preferably 20% by mass or more, and further preferably 50% by mass or more. Thus, it is preferable to produce a conjugated diene-aromatic vinyl copolymer. As a method for quantifying a polymer having a functional group component, it can be measured by chromatography capable of separating a functional group-containing modified component and a non-modified component. As a method using this chromatography, a method in which a GPC column using a polar substance such as silica adsorbing a functional group component as a packing material is used and the internal standard of the non-adsorbed component is used for comparison is suitable. .

  After copolymerization of the conjugated diene compound and the aromatic vinyl compound, before or after reacting the active terminal, a silyl group substituted with two or more alkoxy groups, and a modifier having one or more nitrogen atoms. It is also possible to react the active terminal of the polymer with a polyfunctional modifier. Thus, a co-polymer having a silyl group substituted with two or more alkoxy groups and a modifying group reacted with a modifying agent having one or more nitrogen atoms, and coupled with a multifunctional modifying agent. It can be set as the composition containing coalescence. By reacting the polyfunctional modifier with the active terminal of the copolymer, the cold flow property and processability tend to be improved.

  The polyfunctional modifier is preferably an epoxy group, a carbonyl group, a carboxylic acid ester group, a carboxylic acid amide group, an acid anhydride group, a phosphoric acid ester group, a phosphite group, an epithio group, or a thiocarbonyl group. 1 selected from thiocarboxylic acid ester group, dithiocarboxylic acid ester group, thiocarboxylic acid amide group, imino group, ethyleneimino group, halogen group, alkoxysilyl group, isocyanate group, thioisocyanate group, conjugated diene group, arylvinyl group A compound having more than one kind of functional group is used.

  In the calculation of the number of moles of functional groups, one per epoxy group, carbonyl group, epithio group, thiocarbonyl group, imino group, ethyleneimino group, halogen group, conjugated diene group, arylvinyl group, alkoxysilyl group. The alkoxy group is monofunctional, the carboxylic acid ester group, the carboxylic acid amide group, the acid anhydride group, the thiocarboxylic acid ester group, the dithiocarboxylic acid ester group, the thiocarboxylic acid amide group, the isocyanate group, and the thioisocyanate group are difunctional. The acid ester group and phosphite group are calculated as trifunctional. The polyfunctional modifier that can be preferably used in the present embodiment is one in which the sum of the functional numbers of the above functional groups in one molecule is 2 or more. More preferred is a polyfunctional modifier having a sum of functional numbers of 3 or more.

  Specific examples of the polyfunctional modifier include polyglycidyl ethers of polyhydric alcohols such as ethylene glycol diglycidyl ether and glycerin triglycidyl ether; aromatics having two or more phenyl groups such as diglycidylated bisphenol A Polyglycidyl ethers of group compounds; 1,4-diglycidylbenzene, 1,3,5-triglycidylbenzene, polyepoxy compounds such as polyepoxidized liquid polybutadiene; 4,4′-diglycidyl-diphenylmethylamine, 4,4 Epoxy group-containing tertiary amines such as' -diglycidyl-dibenzylmethylamine; diglycidyl aniline, diglycidyl orthotoluidine, tetraglycidyl metaxylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenyle Glycidylamino compounds such as diamine, diglycidylaminomethylcyclohexane, tetraglycidyl-1,3-bisaminomethylcyclohexane; 3-glycidoxypropyltrimethoxysilane, 3-glycidoxypropyltriethoxysilane, 3-glycidoxy Examples thereof include compounds having an epoxy group and other functional groups such as propyltributoxysilane, epoxy-modified silicone, epoxidized soybean oil, and epoxidized linseed oil.

  In addition, for example, alkoxysilane compounds such as tetramethoxysilane, tetraethoxysilane, tetrabutoxysilane, alkyltriphenoxysilane; N- (1,3-dimethylbutylidene) -3- (triethoxysilyl) -1-propanamine N- (1,3-dimethylbutylidene) -3- (tributoxysilyl) -1-propanamine, N- (1-methylpropylidene) -3- (triethoxysilyl) -1-propanamine, N Examples include compounds having an imino group and an alkoxysilyl group, such as -ethylidene-3- (triethoxysilyl) -1-propanamine, N- (3-triethoxysilylpropyl) -4,5-dihydroimidazole.

  Moreover, for example, isocyanate compounds such as 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, diphenylethane diisocyanate, and 1,3,5-benzene triisocyanate can be mentioned.

  In addition, for example, halogenation of silicon tetrachloride, silicon tetrabromide, silicon tetraiodide, monomethyltrichlorosilicon, monoethyltrichlorosilicon, monobutyltrichlorosilicon, monohexyltrichlorosilicon, monomethyltribromosilicon, bistrichlorosilylethane, etc. Silane compounds; examples thereof include alkoxyhalogenated silane compounds such as monochlorotrimethoxysilane, monobromotrimethoxysilane, dichlorodimethoxysilane, dibromodimethoxysilane, trichloromethoxysilane, and tribromomethoxysilane.

  Further, for example, tin halide compounds such as tin tetrachloride, tin tetrabromide, monomethyltrichlorotin, monoethyltrichlorotin, monobutyltrichlorotin, monophenyltrichlorotin, bistrichlorostannylethane; trichlorophosphine, tribromo Examples include polyhalogenated phosphorus compounds such as phosphine; phosphite compounds such as trisnonylphenyl phosphite, trimethyl phosphite, and triethyl phosphite; and phosphate ester compounds such as trimethyl phosphate and triethyl phosphite.

  Also, for example, carboxylic acid ester compounds such as dimethyl adipate, diethyl adipate, dimethyl terephthalate, diethyl terephthalate, dimethyl phthalate, dimethyl isophthalate; acids such as pyromellitic anhydride and styrene-maleic anhydride copolymer Anhydride group-containing compounds; Amido group-containing compounds such as adipic acid bisdimethylamide and polymethacrylic acid dimethylamide; Carbonyl group-containing compounds such as 4,4′-diacetylbenzophenone and 3-acetylpropoxytrimethoxysilane; Divinylbenzene, Di Aryl vinyl group-containing compounds such as isopropenylbenzene and divinylbenzene oligomers; Halogenated hydrocarbon group-containing compounds such as trichloropropane, tribromopropane, tetrachlorobutane and 3-chloropropoxytrimethoxysilane And the like. These may be used alone or in combination of two or more.

  Further preferable polyfunctional modifiers include those having a functional group having a high affinity with silica, and a 4-6 functional polyepoxy compound having a large effect of improving the molecular weight by coupling, or a total of 4-6. Examples thereof include compounds having both a functional epoxy group and an alkoxysilyl group. Particularly preferred are glycidyl compounds containing an amino group in the molecule, and further compounds having two or three diglycidylamino groups in one molecule. Examples of such compounds include tetraglycidyl metaxylenediamine, tetraglycidylaminodiphenylmethane, tetraglycidyl-p-phenylenediamine, diglycidylaminomethylcyclohexane, tetraglycidyl-1,3-bisaminomethylcyclohexane, and the like. These polyfunctional modifiers may be used alone or in combination of two or more.

  When a polyfunctional modifier is used in the production of the conjugated diene-aromatic vinyl copolymer of the present embodiment, the active terminal of the conjugated diene-aromatic vinyl copolymer is substituted with two or more alkoxy groups. The order in which the compound having one or more nitrogen atoms and the multifunctional modifier are reacted is not particularly limited, and a coupling reaction is performed with the multifunctional modifier, and then the remaining active ends and two are reacted. A silyl group substituted with the above alkoxy group may be reacted with a compound having one or more nitrogen atoms, and a compound having a silyl group substituted with two or more alkoxy groups and one or more nitrogen atoms may be reacted. After the reaction, the remaining active terminal and the polyfunctional modifier may be reacted, or these may be reacted simultaneously. In particular, performing a coupling reaction with a polyfunctional modifier and then reacting the remaining active end with a silyl group substituted with two or more alkoxy groups and a compound having one or more nitrogen atoms This is preferable from the viewpoint of producing a polymer having components at a high rate.

  In the polyfunctional modifier, the total number of moles of the functional group is preferably 0.05 to 0.5 times, more preferably the number of moles of the alkali metal compound and / or alkaline earth metal compound added as the polymerization initiator. Add so that it is in the range of 0.1 to 0.3 times. The above numerical range is preferably 0.05 times or more from the viewpoint of exhibiting sufficient cold flow resistance and workability, and includes a silyl group substituted with two or more alkoxy groups and one or more nitrogen atoms. From the viewpoint of securing an added amount of the compound having the above and obtaining a vulcanizate having good low hysteresis loss, it is preferably 0.5 times or less.

  In the method for producing the modified conjugated diene-aromatic vinyl polymer of the present embodiment, a deactivation agent, a neutralizing agent, etc. may be added to the copolymer solution as necessary after the modification reaction. Good. Examples of the quenching agent include alcohols such as water, methanol, ethanol, and isopropanol. Examples of the neutralizing agent include carboxylic acids such as stearic acid, oleic acid, and versatic acid, aqueous solutions of inorganic acids, and carbon dioxide gas. It is done.

  In addition, since the modified conjugated diene-aromatic vinyl polymer of this embodiment itself has a high viscosity, in order to prevent gel formation in the finishing step after polymerization, or to improve stability during processing, 2,6-di-tert-butyl-4-hydroxytoluene (BHT), n-octadecyl-3- (4′-hydroxy-3 ′, 5′-di-tert-butylphenol) propionate, 2-methyl-4, It is preferable to add a known rubber stabilizer such as 6-bis [(octylthio) methyl] phenol.

  Moreover, in order to improve the workability of the modified conjugated diene-aromatic vinyl copolymer of the present embodiment, an extending oil can be added to the copolymer as necessary. In this case, it is preferable to obtain the oil-extended copolymer solution by adding the extending oil to the polymer solution and mixing to remove the solvent. As the extender oil, aroma oil, naphthene oil, paraffin oil, and an aroma substitute oil containing 3% by mass or less of a polycyclic aromatic component by the IP346 method are suitably used. Among these, it is preferable to use an aroma substitute oil having a polycyclic aromatic component of 3% by mass or less from the viewpoint of environmental safety, prevention of oil bleed, and wet grip characteristics. Examples of the aroma substitute oil include RAE and the like in addition to TDAE and MES shown in Kautschuk Gummi Kunststoff 52 (12) 799 (1999). The amount of the extender oil used is arbitrary, but is usually 10 to 60 parts by weight, preferably 20 to 37.5 parts by weight with respect to 100 parts by weight of the polymer.

  As a method for obtaining the modified conjugated diene-aromatic vinyl copolymer of the present embodiment from the polymer solution, a conventionally known method can be applied. For example, after separating the solvent by steam stripping or the like, the polymer is separated by filtration, further dehydrated and dried to obtain the polymer, concentrated in a flushing tank, and further devolatilized by a vent extruder or the like. A method, a method of directly devolatilizing with a drum dryer or the like can be applied.

  The modified conjugated diene-aromatic vinyl copolymer of this embodiment is suitably used as a vulcanizate. The vulcanized product may be, for example, a modified conjugated diene-aromatic vinyl copolymer of the present embodiment, an inorganic filler such as a silica-based inorganic filler or carbon black, if necessary, other than the copolymer of the present embodiment. After mixing with rubber, silane coupling agent, rubber softener, vulcanizing agent, vulcanization accelerator / auxiliary, etc. to make a modified conjugated diene-aromatic vinyl copolymer composition, vulcanize by heating. Can be obtained.

  In the conjugated diene-aromatic vinyl copolymer composition, a rubbery polymer other than the conjugated diene-aromatic vinyl copolymer described above can be used in combination with the conjugated diene-aromatic vinyl copolymer of the present embodiment. .

  Examples of such rubber-like polymers include conjugated diene polymers or hydrogenated products thereof, random copolymers of conjugated diene compounds and vinyl aromatic compounds or hydrogenated products thereof, conjugated diene compounds and vinyl aromatics. And a block copolymer with a group compound or a hydrogenated product thereof, a non-diene polymer, and natural rubber. Specifically, butadiene rubber or hydrogenated product thereof, isoprene rubber or hydrogenated product thereof, styrene-butadiene rubber or hydrogenated product thereof, styrene-butadiene block copolymer or hydrogenated product thereof, styrene-isoprene block copolymerized Examples thereof include styrene-based elastomers such as coalescence or hydrogenated products thereof, acrylonitrile-butadiene rubber, or hydrogenated products thereof.

  Non-diene polymers include ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, ethylene-butene rubber, ethylene-hexene rubber, ethylene-octene rubber, and other olefinic elastomers, butyl rubber, brominated butyl rubber. Acrylic rubber, fluorine rubber, silicone rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, α, β-unsaturated nitrile-acrylate ester-conjugated diene copolymer rubber, urethane rubber, polysulfide rubber and the like.

  The various rubber-like polymers described above may be modified rubbers provided with functional groups. The weight average molecular weight is preferably 2,000 to 2,000,000, more preferably 5,000 to 15,000,000, from the viewpoint of the balance between performance and processing characteristics. Also, so-called liquid rubber having a low molecular weight can be used. These rubbery polymers may be used alone or in combination of two or more.

  When the above-described rubber-like polymer is used in combination with the modified conjugated diene-aromatic vinyl copolymer of the present embodiment, these ratios are expressed as a modified conjugated diene-aromatic vinyl copolymer / rubber-like polymer. 20/80 to 100/0 is preferable, 30/70 to 90/10 is more preferable, and 50/50 to 80/20 is further preferable. When the ratio of the modified conjugated diene-aromatic vinyl copolymer / rubbery polymer is within the above range, the vulcanizate has an excellent balance between low hysteresis loss and wet skid resistance, and also satisfies wear resistance and fracture strength. Tend to be able to get.

Examples of the silica-based inorganic filler that can be suitably used in the modified conjugated diene-aromatic vinyl copolymer composition include solid particles containing SiO ₂ or Si ₃ Al as a main component. Examples thereof include inorganic fibrous substances such as silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, glass fiber, and the like. Further, a silica-based inorganic filler having a hydrophobic surface or a mixture of a silica-based inorganic filler and a non-silica inorganic filler can also be used. Among these, silica and glass fiber are preferable from the viewpoint of reinforcing properties, and silica is more preferable.

  As silica, dry silica, wet silica, synthetic silicate silica, and the like can be used. Among them, wet silica is preferable because the effect of improving the fracture characteristics and the effect of achieving both wet skid resistance tend to be remarkable.

In the modified conjugated diene-aromatic vinyl copolymer composition, from the viewpoint of obtaining practically good wear resistance and fracture characteristics, the nitrogen adsorption specific surface area required by the BET adsorption method of silica-based inorganic filler is 100 to 300 m. it is preferably ² / g, and more preferably 170~250m ² / g. If necessary, a silica-based inorganic filler having a relatively small specific surface area, for example, a specific surface area of 200 m ² / g or less, and a silica-based inorganic filler having a relatively large specific surface area, for example, 200 m ² / g or more, By using in combination, it is possible to highly balance good wear resistance and fracture characteristics with low hysteresis loss.

  As described above, the compounding amount of the silica-based inorganic filler in the modified conjugated diene-aromatic vinyl copolymer composition is 100 parts by mass of the rubber component containing the conjugated diene-aromatic vinyl copolymer of the present embodiment. It is preferable that it is 0.5-300 mass parts, 5-200 mass parts is more preferable, and 20-100 mass parts is further more preferable. The compounding amount of the silica-based inorganic filler is preferably 0.5 parts by mass or more from the viewpoint of manifesting the effect of adding the inorganic filler. On the other hand, the inorganic filler is sufficiently dispersed to process the composition. And from the viewpoint of making the mechanical strength practically sufficient, it is preferably 300 parts by mass or less.

Carbon black may be added to the modified conjugated diene-aromatic vinyl copolymer composition.
As the carbon black, carbon black of each class such as SRF, FEF, HAF, ISAF, and SAF can be used, and carbon black having a nitrogen adsorption specific surface area of 50 m ² / g or more and a DBP oil absorption of 80 mL / 100 g is preferable.

  The blending amount of the carbon black is preferably 0.5 to 100 parts by mass, more preferably 3 to 100 parts by mass with respect to 100 parts by mass of the rubber component containing the modified conjugated diene-aromatic vinyl copolymer of the present embodiment. 5-50 mass parts is more preferable. The blending amount of the carbon black is preferably 0.5 parts by mass or more from the viewpoint of expressing performances required for tires such as dry grip performance and conductivity, and 100 parts by mass from the viewpoint of dispersibility. The following is preferable.

  In addition to the silica-based inorganic filler and carbon black, a metal oxide or a metal hydroxide may be added to the modified conjugated diene-aromatic vinyl copolymer composition.

The metal oxide refers to solid particles having the chemical formula M _x O _y (M is a metal atom, x and y are each an integer of 1 to 6) as a main component of a structural unit, such as alumina, titanium oxide, Magnesium oxide, zinc oxide, or the like can be used. A mixture of a metal oxide and an inorganic filler other than the metal oxide can also be used.

  Examples of the metal hydroxide include aluminum hydroxide, magnesium hydroxide, zirconium hydroxide and the like.

The modified conjugated diene-aromatic vinyl copolymer composition may contain a silane coupling agent.
The silane coupling agent has a function to close the interaction between the rubber component and the silica-based inorganic filler, and has an affinity or binding group for each of the rubber component and the silica-based inorganic filler. In general, a compound having a sulfur bond portion, an alkoxysilyl group, and a silanol group portion in one molecule is used. Specifically, bis- [3- (triethoxysilyl) -propyl] -tetrasulfide, bis- [3- (triethoxysilyl) -propyl] -disulfide, bis- [2- (triethoxysilyl) -ethyl ] -Tetrasulfide etc. are mentioned.

  0.1-30 mass parts is preferable with respect to 100 mass parts of silica type inorganic fillers mentioned above, as for the compounding quantity of a silane coupling agent, 0.5-20 mass parts is more preferable, and 1-15 mass parts is. Further preferred. The said effect by a silane coupling agent can be effectively acquired as the compounding quantity of a silane coupling agent is the said range.

  In order to improve processability, the modified conjugated diene-aromatic vinyl copolymer composition may contain a rubber softener. As the rubber softener, mineral oil or a liquid or low molecular weight synthetic softener is suitable.

  The mineral oil rubber softener called process oil or extender oil used for softening, increasing volume and improving processability of rubber is a mixture of aromatic ring, naphthene ring and paraffin chain. A paraffin chain having 50% or more carbon atoms in the total carbon is called paraffinic, a naphthene ring having 30 to 45% carbon is naphthenic, and an aromatic carbon having more than 30% aromatic is aromatic. It is called a system. As the rubber softener used together with the modified conjugated diene-aromatic vinyl copolymer of the present embodiment, those having an appropriate aromatic content are preferred because they tend to be familiar with the copolymer.

  The blending amount of the rubber softening agent is preferably 0 to 100 parts by mass, more preferably 10 to 90 parts by mass with respect to 100 parts by mass of the rubber component containing the conjugated diene-aromatic vinyl copolymer of the present embodiment. 30 to 90 parts by mass are more preferable. If the blending amount of the rubber softener exceeds 100 parts by mass with respect to 100 parts by mass of the rubber component, bleeding out tends to occur, and the composition surface may become sticky.

  Additives such as the modified conjugated diene-aromatic vinyl copolymer of this embodiment and other rubbery polymers, silica-based inorganic fillers, carbon black and other fillers, silane coupling agents, rubber softeners, etc. The method for mixing is not particularly limited. For example, a melt kneading method using a general blender such as an open roll, a Banbury mixer, a kneader, a single screw extruder, a twin screw extruder, a multi-screw extruder, etc. The method of removing by heating, etc. are mentioned. Of these, a melt kneading method using a roll, a Banbury mixer, a kneader, or an extruder is preferred from the viewpoint of productivity and good kneading properties.

  In addition, any of a method of kneading the modified conjugated diene-aromatic vinyl copolymer and various compounding agents at a time and a method of mixing in multiple times can be applied.

  The modified conjugated diene-aromatic vinyl copolymer composition may be a vulcanized composition that has been vulcanized with a vulcanizing agent.

  As the vulcanizing agent, for example, radical generators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur and sulfur compounds can be used. Sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, polymeric polysulfur compounds, and the like.

  The amount of the vulcanizing agent is usually 0.01 to 20 parts by mass with respect to 100 parts by mass of the rubber component containing the modified conjugated diene-aromatic vinyl copolymer of the present embodiment, and 0.1 to 15 Part by mass is preferred.

  A conventionally known method can be applied as the vulcanization method, and the vulcanization temperature is usually 120 to 200 ° C, preferably 140 to 180 ° C.

  In vulcanization, a vulcanization accelerator may be used as necessary. As the vulcanization accelerator, conventionally known materials can be used. For example, sulfenamide, guanidine, thiuram, aldehyde-amine, aldehyde-ammonia, thiazole, thiourea, dithiocarbamate And the like. Further, as the vulcanization aid, zinc white, stearic acid or the like can be used.

  The amount of the vulcanization accelerator used is usually 0.01 to 20 parts by mass with respect to 100 parts by mass of the rubber component containing the conjugated diene-aromatic vinyl copolymer of the present embodiment, and 0.1 to 15 Part by mass is preferred.

  The modified conjugated diene-aromatic vinyl copolymer composition includes other softening agents and fillers other than those described above, as well as heat resistance stabilizers, antistatic agents, and weather resistance stability, within the range not impairing the object of the present invention. Various additives such as an agent, an anti-aging agent, a coloring agent, and a lubricant may be used.

  As other softeners, known softeners can be used.

  Specific examples of other fillers include calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate.

  Known materials can be applied as the heat resistance stabilizer, antistatic agent, weather resistance stabilizer, anti-aging agent, colorant, and lubricant.

Hereinafter, the present embodiment will be described more specifically with reference to examples and comparative examples. However, the present embodiment is not limited to the following examples as long as the gist of the present embodiment is not exceeded.
In addition, the analysis of the sample in a manufacture example was performed by the method shown below.
(1) Amount of bound styrene A sample was used as a chloroform solution, and the amount of bound styrene (mass%) was measured by absorption at UV254 nm by the phenyl group of styrene (manufactured by Shimadzu Corporation: UV-2450).

(2) Microstructure of butadiene moiety (1,2-vinyl bond content)
The sample was a carbon disulfide solution, the infrared spectrum was measured in the range of 600 to 1000 cm ⁻¹ using a solution cell, and the microstructure of the butadiene portion was determined from the absorbance at a predetermined wave number according to the calculation formula of the Hampton method ( JASCO Corporation FT-IR230).

(3) Mooney viscosity According to JIS K 6300, preheating was performed at 100 ° C. for 1 minute, and the viscosity after 4 minutes was measured.

(4) Weight average molecular weight and molecular weight distribution Using GPC with three columns connected with polystyrene gel as a filler, the chromatogram was measured, and the weight average molecular weight and molecular weight were determined by a calibration curve using standard polystyrene. The number average molecular weight was determined, and the molecular weight distribution index (Mw / Mn) was calculated from the ratio of the weight average molecular weight to the number average molecular weight.
Tetrahydrofuran (THF) was used as the eluent.
As the column, guard column: Tosoh TSKguardcolumn HHR-H, column: Tosoh TSKgel G6000HHR, TSKgel G5000HHR, TSKgel G4000HHR were used.
The weight average molecular weight was measured using an RI detector of HLC8020 manufactured by Tosoh under conditions of an oven temperature of 40 ° C. and a THF flow rate of 1.0 mL / min. Further, in order to confirm the presence of a polymer block having a larger amount of conjugated diene bonds than the average composition of the copolymer, a comparison was made with a chromatogram obtained with a UV detector (wavelength: 254 nm).
A sample was measured by dissolving 10 mg in 20 mL of THF and injecting 200 μL.

(5) Modification rate Applying the property that the modified component is adsorbed on a GPC column with silica gel as a filler, using a sample solution containing a sample and standard polystyrene having a weight average molecular weight of 5000 (polystyrene does not adsorb on the column) GPC of the polystyrene gel column and silica column (guard column: DIOL 4.6 × 12.5 mm 5 micron, column: Zorbax PSM-1000S, PSM-300S, PSM-60S, oven temperature 40 ° C., THF flow rate 0 .5 mL / min) GPC (Tosoh CCP8020 series build-up GPC system: AS-8020, SD-8022, CCPS, CO-8020, RI-8021) Both chromatograms were measured using an RI detector. The amount of adsorption on the silica column is measured from the difference between them. The modification rate was determined.
As a sample, 10 mg was dissolved in 20 mL of THF together with 5 mg of standard polystyrene, and 200 μL was injected for measurement.
As a specific procedure, the peak area of the chromatogram using the polystyrene column is set to 100, the peak area of the standard polystyrene is P2, the peak area of the standard polystyrene is P2, and the peak area of the chromatogram using the silica column is P1. As a whole, the sample peak area was P3, the peak area of standard polystyrene was P4, and the modification rate (%) was calculated by the formula [1- (P2 × P3) / (P1 × P4)] × 100. .

(6) Glass transition temperature (Tg)
In accordance with ISO 22768: 2006, a DSC curve was recorded while increasing the temperature from −100 ° C. to 20 ° C./min under a flow of helium at 50 mL / min using a DSC3200S manufactured by Mac Science, and the peak top of the DSC differential curve (Inflection point) Was the glass transition temperature.

[Example 1]
An autoclave having an internal volume of 10 liters and equipped with a stirrer and a jacket and capable of temperature control was used as a reactor. The reactor was placed in a reactor having 53 g of butadiene and 2474 g of cyclohexane from which impurities had been removed in advance, and the internal temperature was maintained at 60 ° C. Here, 9.3 mmol of n-butyllithium was added as a polymerization initiator to initiate polymerization, and the reaction was continued for 15 minutes. Then, when the temperature inside the reactor was adjusted to 42 ° C. by adjusting the temperature of the jacket, a small amount of polymer solution was sufficiently introduced from the reactor into a mixed solution of about 1 mL of methanol and about 30 mL of cyclohexane so that contact with air did not occur. After careful extraction, the solvent was removed to obtain a sampling polymer.
Thereafter, 1.03 g of 2,2-bis (2-oxolanyl) propane as a polar substance is added to the reactor, and then 724 g of butadiene, 273 g of styrene, and 2326 g of cyclohexane are respectively supplied to the reactor at a constant rate over 20 minutes. did.
After the start of the polymerization reaction, the temperature inside the reactor started to rise due to the exotherm caused by the polymerization, and the final temperature in the reactor reached 76 ° C.
After the completion of the polymerization reaction, 0.35 mmol of tetraglycidyl-1,3-bisaminomethylcyclohexane was added to the reactor, and the modification reaction was carried out by stirring at 74 ° C. for 2 minutes. Thereafter, 6.23 mmol of 1- [3- (triethoxysilyl) propyl] -4-methylpiperazine was further added, and a denaturing reaction was performed at 72 ° C. for 5 minutes.
After adding 2.1 g of an antioxidant (BHT) to this polymer solution, the solvent is removed by steam stripping, and a drying treatment is performed by a dryer, so that a styrene-butadiene copolymer having a modifying component (sample) A) was obtained.
As a result of analyzing (Sample A), the amount of bound styrene was 26% by mass, and the amount of bound butadiene was 74% by mass.
The Mooney viscosity of the polymer was 57.
The amount of 1,2-vinyl bond in the butadiene bond unit calculated from the measurement result using an infrared spectrophotometer according to the Hampton method was 55 mol%, and was determined from GPC using a silica-based column. The modification rate was 80%.
The weight average molecular weight in terms of polystyrene determined by GPC using a polystyrene column was 324,000, and Mw / Mn was 1.36. The chromatograms detected by both the RI and UV detectors are converted, and the horizontal axis is the logarithm of the molecular weight in terms of polystyrene, and the detection intensity is normalized so that the elution areas of the chromatograms at both detectors are equal. When comparing the graphs obtained from the low molecular weight side with the RI detector, the graph starts to rise when the molecular weight is about 9000 or more, whereas with the UV detector, the graph starts to rise when the molecular weight is about 20,000, and about 60,000. From the above, it was observed that both graphs matched within 5%, confirming the formation of a polybutadiene block.
The 1,2-vinyl bond content of the sampling polymer during polymerization of the polybutadiene block was 9 mol%, and the weight average molecular weight in terms of polystyrene was 9000.

[Example 2]
Example 1 except that the modifier was changed from 1- [3- (triethoxysilyl) propyl] -4-methylpiperazine to 1- [3- (triethoxysilyl) propyl] -4- (trimethylsilyl) piperazine. (Sample B) was obtained by the same method.
The analysis results of (Sample B) are shown in Table 1.

[Example 3]
An autoclave having an internal volume of 10 liters and equipped with a stirrer and a jacket and capable of temperature control was used as a reactor, and 770 g of butadiene, 273 g of styrene and 2350 g of cyclohexane from which impurities had been previously removed were placed in the reactor, and the internal temperature was 60 ° C. Held on. Here, 9.3 mmol of n-butyllithium was added as a polymerization initiator to start polymerization, and the reaction was continued for 15 minutes. Then, when the temperature inside the reactor was adjusted to 42 ° C. by adjusting the temperature of the jacket, a small amount of polymer solution was sufficiently introduced from the reactor into a mixed solution of about 1 mL of methanol and about 30 mL of cyclohexane so that contact with air did not occur. After careful extraction, the solvent was removed to obtain a sampling polymer.
Thereafter, 0.98 g of 2,2-bis (2-oxolanyl) propane as a polar substance was added to the reactor, and the temperature inside the reactor started to rise due to the heat generated by the polymerization. Reached 75 ° C.
After the completion of the polymerization reaction, 0.35 mmol of tetraglycidyl-1,3-bisaminomethylcyclohexane was added to the reactor, and the mixture was stirred at 73 ° C. for 2 minutes to carry out a modification reaction. Thereafter, 6.23 mmol of 2- [3- (trimethoxysilyl) propyl] -1,3-dimethylimidazolidine was further added, and a denaturing reaction was carried out at 71 ° C. for 5 minutes.
After adding 2.1 g of an antioxidant (BHT) to this polymer solution, the solvent is removed by steam stripping, and a drying treatment is performed by a dryer, so that a styrene-butadiene copolymer having a modifying component (sample) C) was obtained.
As a result of analyzing (Sample C), the amount of bound styrene was 26% by mass and the amount of bound butadiene was 74% by mass.
The Mooney viscosity of the polymer was 56.
The 1,2-bond amount of the microstructure of the butadiene portion determined by calculation according to the Hampton method from the measurement results using an infrared spectrophotometer is 55 mol%, and is also determined from GPC using a silica-based adsorption column. The modification rate was 79%.
Further, the amount of bound styrene in the midway sampling polymer after the first block polymerization was 2% by mass, the amount of 1,2-vinyl bond was 9% by mole, and the weight average molecular weight in terms of polystyrene was 11,000.

[Comparative Example 1]
An autoclave having an internal volume of 10 liters and equipped with a stirrer and a jacket and capable of temperature control was used as a reactor, 2350 g of cyclohexane from which impurities had been previously removed, and 2,2-bis (2-oxolanyl) propane as a polar substance in an amount of 0. 94 g and 9.3 mmol of n-butyllithium as a polymerization initiator were put into the reactor, and the internal temperature was kept at 42 ° C. Here, 777 g of butadiene from which impurities had been previously removed, 273 g of styrene, and 2450 g of cyclohexane were each fed to the reactor at a constant rate over 20 minutes.
After the start of the polymerization reaction, the temperature inside the reactor started to rise due to the exotherm caused by the polymerization, and the final temperature in the reactor reached 76 ° C.
After the completion of the polymerization reaction, 0.35 mmol of tetraglycidyl-1,3-bisaminomethylcyclohexane was added to the reactor, and the modification reaction was carried out by stirring at 74 ° C. for 2 minutes. Thereafter, 6.23 mmol of 1- [3- (triethoxysilyl) propyl] -4-methylpiperazine was further added, and a denaturing reaction was performed at 72 ° C. for 5 minutes.
After adding 2.1 g of an antioxidant (BHT) to this polymer solution, the solvent is removed by steam stripping, and a drying treatment is performed by a dryer, so that a styrene-butadiene copolymer having a modifying component (sample) D) was obtained.
As a result of analyzing (Sample D), the amount of bound styrene was 26 mass%, and the amount of bound butadiene was 74 mass%.
The Mooney viscosity of the polymer was 56.
The 1,2-bond amount of the microstructure of the butadiene portion determined by calculation according to the Hampton method from the measurement results using an infrared spectrophotometer is 55 mol%, and is also determined from GPC using a silica-based adsorption column. The denaturation rate was 81%.
The chromatograms detected by both the RI and UV detectors are converted, and the horizontal axis is the logarithm of the molecular weight in terms of polystyrene, and the detection intensity is standardized so that the elution areas of the chromatograms at both detectors are equal. As a result, the graph started to rise from a molecular weight of about 10,000 for both detectors, and it was confirmed that the polybutadiene block as seen in Example 1 was not formed.

[Examples 4 to 6, Comparative Example 2]
Using the samples shown in Table 1 (samples A to D) as raw rubber, rubber compositions containing the respective raw rubbers were obtained according to the formulation shown below.
Modified Conjugated Diene-Aromatic Vinyl Copolymer (Samples A to D) 70.0 parts by mass of natural rubber (Mooney viscosity adjusted to 60 by mastication) 30.0 parts by mass of silica (Ultrasil VN3 manufactured by Degussa) 75 0.0 part by mass carbon black (N339 manufactured by Tokai Carbon Co., Ltd.) 5.0 parts by mass silane coupling agent (Si69 manufactured by Degussa) 7.5 parts by mass S-RAE oil (JOMO process NC140 manufactured by Japan Energy) 37.5 parts by mass Parts zinc white 2.5 parts by weight stearic acid 2.0 parts by weight anti-aging agent (N-isopropyl-N'-phenyl-p-phenylenediamine) 2.0 parts by weight sulfur 1.7 parts by weight vulcanization accelerator (N -Cyclohexyl-2-benzothiazylsulfinamide) 1.7 parts by mass vulcanization accelerator (diphenylguanidine) 1.5 parts by mass total 236. 4 parts by mass

The rubber composition was kneaded by the following method.
Using a closed kneading machine (with an internal volume of 0.3 liters) equipped with a temperature control device, as the first stage kneading, under the conditions of a filling rate of 65% and a rotor rotational speed of 50/57 rpm, the raw rubber (samples A to D) , Natural rubber), filler (silica, carbon black), organic silane coupling agent, process oil, zinc white, and stearic acid.
At this time, the temperature of the closed mixer was controlled, and the rubber composition was obtained at a discharge temperature (compound) of 155 to 160 ° C.
Next, as the second stage kneading, the blend obtained above was cooled to room temperature, an anti-aging agent was added, and kneaded again to improve silica dispersion. Also in this case, the discharge temperature (formulation) was adjusted to 155 to 160 ° C. by controlling the temperature of the mixer.
After cooling, as a third stage of kneading, sulfur and a vulcanization accelerator were added and kneaded with an open roll set at 70 ° C.
Then, it shape | molded and vulcanized with the vulcanization press for 20 minutes at 160 degreeC.
After vulcanization, the physical properties of the rubber composition were measured. The physical property measurement results are shown in Table 2 below.

The physical properties of the rubber composition were measured by the following methods.
(1) Bound rubber amount Formulation after completion of the second stage kneading step: About 0.2 gram was cut into a square of about 1 mm, put into a Harris basket (100 mesh wire mesh), and the mass was measured.
Then, after being immersed in toluene for 24 hours, a drying treatment was performed and the mass was measured.
The amount of rubber bound to the filler (modified conjugated diene polymer + natural rubber) was calculated from the amount of the undissolved component, and the ratio of the rubber bound to the filler to the amount of rubber in the first blend was determined.

(2) Compound Mooney Viscosity Using a Mooney viscometer, according to JIS K6300-1, after preheating at 130 ° C. for 1 minute, the rotor was rotated at 2 revolutions per minute, and the viscosity after 4 minutes was measured.

(3) Tensile strength Measured by the tensile test method of JIS K6251 and indexed with Comparative Example 2 as 100.

(4) Viscoelastic parameters Viscoelastic parameters were measured in a torsion mode using a viscoelasticity tester (ARES) manufactured by Rheometrics Scientific. Each measured value was indexed with Comparative Example 2 as 100.
Tan δ measured at 0 ° C. with a frequency of 10 Hz and a strain of 1% was used as an index of wet grip performance. A larger value indicates better wet grip performance.
Further, tan δ measured at 50 ° C. with a frequency of 10 Hz and a strain of 3% was used as an index of fuel saving characteristics. The smaller the value, the better the fuel saving performance.

(5) Abrasion resistance Using an Akron abrasion tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.), according to JIS-K6264-2, the amount of wear at a load of 44.1 N and 1000 rotations was measured, and the comparative example 2 was indexed as 100. . The larger the index, the better the wear resistance.

  As shown in Table 2 above, the modified conjugated diene-aromatic vinyl copolymer compositions of Examples 4 to 6 have a low Payne effect and excellent silica dispersibility in the silica blend composition, and low tan δ at high temperatures. There was little hysteresis loss, low rolling resistance of the tire was realized, and low temperature tan δ was high and wet skid resistance was excellent. Furthermore, the wear resistance and tensile strength were good.

  When used as a tire tread material, the rubber composition containing the modified conjugated diene-aromatic vinyl copolymer of the present invention has an excellent balance between low hysteresis loss and wet skid resistance, and has practically sufficient resistance. It is possible to obtain a tire tread that also satisfies wear characteristics and fracture characteristics. Moreover, it can be used suitably also for uses, such as footwear and industrial goods.

Claims (10)

A copolymer comprising a conjugated diene compound and an aromatic vinyl compound,
The conjugated diene bond amount of the copolymer is 50 to 85% by mass, the aromatic vinyl bond amount is 15 to 50% by mass,
A functional group containing one or more nitrogen atoms and a silyl group substituted with one or more alkoxy groups at one end of the polymer chain;
A polymer block having a higher amount of conjugated diene bonds than the average composition of the copolymer at the other end of the polymer chain, and having a weight average molecular weight in terms of polystyrene determined by gel permeation chromatography of 2,000- Having 50,000 polymer blocks,
Modified conjugated diene-aromatic vinyl copolymer.   The modified conjugate according to claim 1, wherein the amount of conjugated diene in the polymer block having a larger amount of conjugated diene bonds than the average composition of the copolymer is 95% by mass or more and the amount of aromatic vinyl bonds is 5% by mass or less. Diene-aromatic vinyl copolymer.   The modified conjugated diene-fragrance according to claim 1 or 2, wherein the vinyl bond content in the conjugated diene bond unit in the polymer block having a higher conjugated diene bond content than the average composition of the copolymer is 5 to 25 mol%. Group vinyl copolymer. The terminal functional part of the modified conjugated diene-aromatic vinyl copolymer has the following formula (1)

(In Formula (1), Polym is a copolymer chain, R ¹ and R ² are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group, and R ³ is 1 to 20 carbon atoms. R ⁴ and R ⁵ are hydrocarbon groups having 1 to 6 carbon atoms which may be the same or different, and form a ring structure of 5 or more members with two adjacent Ns, R ⁶ is a hydrocarbon group having 1 to 20 carbon atoms, or a 3 organic substituted silyl group, and m and n are 1 or 2 and m + n is an integer that is 3 or less.)
Or the following formula (2)

(In the formula (2), Polym, R ^{1 to} R ⁶ , m, and n have the same meanings as the formula (1), and R ⁷ is a hydrocarbon group having 1 to 20 carbon atoms, or a 3 organic substituted silyl group. is there.)
The modified conjugated diene-aromatic vinyl copolymer of any one of Claims 1-3 represented by these. A method for producing a modified conjugated diene-aromatic vinyl copolymer according to any one of claims 1 to 4,
A polymer block in which an alkali metal compound or an alkaline earth metal compound is used as a polymerization initiator, a conjugated diene compound is mainly polymerized as a first step, and the amount of conjugated diene bonds is larger than the average composition of the copolymer. After forming a polymer block having a weight average molecular weight of 2,000 to 50,000 in terms of polystyrene, a conjugated diene having an active end is obtained by randomly copolymerizing a conjugated diene compound and an aromatic vinyl compound as the second step. A polymerization step for obtaining an aromatic vinyl copolymer;
A modification step of reacting a compound having one or more nitrogen atoms with a silyl group substituted with two or more alkoxy groups at the active end of the conjugated diene-aromatic vinyl copolymer;
A process for producing a modified conjugated diene-aromatic vinyl copolymer.   The first block of the polymerization process is carried out in the state where only the conjugated diene compound is present as a monomer, and the polymer block has a conjugated diene bond amount larger than the average composition of the copolymer, and is a weight average in terms of polystyrene After forming a polymer block having a molecular weight of 2,000 to 50,000, the second stage copolymerization reaction is carried out by adding both an aromatic vinyl compound or an aromatic vinyl compound and a conjugated diene compound into the polymerization system. The manufacturing method of the modified conjugated diene-aromatic vinyl copolymer of Claim 5 implemented.   The method for producing a modified conjugated diene-aromatic vinyl copolymer according to claim 6, comprising a step of adding a polar compound when carrying out the second-stage copolymerization reaction.   A polymer block in which the first step of the polymerization process is carried out in the presence of a conjugated diene compound and an aromatic vinyl compound as monomers, and the amount of conjugated diene bonds is larger than the average composition of the copolymer, and is converted to polystyrene The modified conjugated diene-fragrance according to claim 5, wherein a second block copolymerization reaction is carried out by adding a polar compound after forming a polymer block having a weight average molecular weight of 2,000 to 50,000. For producing an aromatic vinyl copolymer. The compound having a silyl group substituted with two or more alkoxy groups and one or more nitrogen atoms is represented by the following formula (3):

(In the formula ^{(3), R 1, R} 2 are each independently an alkyl group having 1 to 20 carbon atoms, or an aryl group, R ³ is an alkylene group having 1 to 20 carbon atoms, R ^4, R ⁵ is a hydrocarbon group having 1 to 6 carbon atoms which may be the same or different, and forms a ring structure of 5 or more members with two adjacent Ns, and R ⁶ has 1 to 20 carbon atoms (It is a hydrocarbon group or a 3 organic substituted silyl group, and p is an integer of 2 or 3.)
Or the following formula (4)

(In Formula (4), R < ¹ > -R < ⁶ >, p is synonymous with said Formula (3), and R < ⁷ > is a C1-C20 hydrocarbon group or a 3 organic substituted silyl group.)
The manufacturing method of the modified conjugated diene-aromatic vinyl copolymer of any one of Claims 5-8 represented by these.   The silica-based inorganic filler is added in an amount of 0.5 to 300 parts by mass with respect to 100 parts by mass of the rubber component containing 20 parts by mass or more of the modified conjugated diene-aromatic vinyl copolymer according to any one of claims 1 to 4. A modified conjugated diene-aromatic vinyl copolymer composition obtained by blending.