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WO2025192482A1 - Polymère à base de diène conjugué, procédé de production d'un polymère à base de diène conjugué, et composition de caoutchouc - Google Patents

Polymère à base de diène conjugué, procédé de production d'un polymère à base de diène conjugué, et composition de caoutchouc

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Publication number
WO2025192482A1
WO2025192482A1 PCT/JP2025/008609 JP2025008609W WO2025192482A1 WO 2025192482 A1 WO2025192482 A1 WO 2025192482A1 JP 2025008609 W JP2025008609 W JP 2025008609W WO 2025192482 A1 WO2025192482 A1 WO 2025192482A1
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WO
WIPO (PCT)
Prior art keywords
conjugated diene
diene polymer
molecular weight
polymer
mass
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
PCT/JP2025/008609
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English (en)
Japanese (ja)
Inventor
優一 伊勢
新一 関川
亮介 宍戸
謙太 久村
大祐 早田
知宏 近藤
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Asahi Kasei Corp
Asahi Chemical Industry Co Ltd
Original Assignee
Asahi Kasei Corp
Asahi Chemical Industry Co Ltd
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Filing date
Publication date
Application filed by Asahi Kasei Corp, Asahi Chemical Industry Co Ltd filed Critical Asahi Kasei Corp
Publication of WO2025192482A1 publication Critical patent/WO2025192482A1/fr
Pending legal-status Critical Current
Anticipated expiration legal-status Critical

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Classifications

    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08C—TREATMENT OR CHEMICAL MODIFICATION OF RUBBERS
    • C08C19/00—Chemical modification of rubber
    • C—CHEMISTRY; METALLURGY
    • C08—ORGANIC MACROMOLECULAR COMPOUNDS; THEIR PREPARATION OR CHEMICAL WORKING-UP; COMPOSITIONS BASED THEREON
    • C08L—COMPOSITIONS OF MACROMOLECULAR COMPOUNDS
    • C08L9/00—Compositions of homopolymers or copolymers of conjugated diene hydrocarbons

Definitions

  • the present invention relates to a conjugated diene polymer, a method for producing a conjugated diene polymer, and a rubber composition.
  • Examples of rubber materials that meet the above-mentioned requirements include rubber materials containing a rubber-like polymer and a reinforcing filler such as carbon black or silica.
  • a rubber material containing silica can improve the balance between low hysteresis loss and wet skid resistance.
  • Patent Documents 1 to 3 propose compositions of silica and a modified conjugated diene polymer obtained by reacting an alkoxysilane containing an amino group with an active terminal of a conjugated diene polymer.
  • Patent Document 4 proposes a modified conjugated diene polymer obtained by subjecting an active terminal of a polymer to a coupling reaction with a polyfunctional silane compound.
  • conjugated diene polymers are being made with higher molecular weights in order to improve their abrasion resistance.
  • high-molecular-weight conjugated diene polymers have the problem that polymer particles tend to peel off from the surface of the bale of the conjugated diene polymer itself, contaminating the area around the molding machine and the area around the conveyor that transports the bale after molding, leaving room for improvement in terms of the working environment.
  • increasing the molecular weight of conjugated diene polymers is accompanied by an increase in the viscosity of the composition, which tends to result in poor dispersion of reinforcing fillers such as carbon black and silica during kneading, leaving room for improvement in terms of processability as well.
  • reinforcing fillers such as carbon black and silica during kneading
  • Patent Document 5 discloses a method of suppressing peeling of polymer particles from the surface of a veil by adding a process oil to a solution of a conjugated diene polymer to form an oil-extended conjugated diene polymer.
  • conjugated diene polymers are made to have a high molecular weight to improve wear resistance
  • process oil it is common to add process oil to produce oil-extended conjugated diene polymers in order to improve bale moldability and processability after kneading.
  • process oil there has been a desire to reduce the amount of process oil added to conjugated diene polymers as much as possible in order to increase the degree of freedom in compounding when preparing rubber compositions.
  • the present invention therefore aims to provide a conjugated diene polymer that, even when not oil-extended and without the addition of process oil, has excellent bale moldability and good processability when vulcanized, while also allowing good mixer torque when kneaded with filler, allowing the filler to be adequately dispersed, resulting in a rubber composition that, when vulcanized, has high hardness and good abrasion resistance.
  • a conjugated diene polymer whose molecular weight distribution curve obtained by gel permeation chromatography (GPC) measurement is unimodal with a shoulder on the high molecular weight side, has a predetermined weight average molecular weight (Mw), molecular weight distribution, and modification rate, and whose degree of branching in the high molecular weight region is equal to or greater than a predetermined value, has excellent processability when vulcanized, and when vulcanized, has high hardness and good abrasion resistance, leading to the completion of the present invention.
  • GPC gel permeation chromatography
  • a conjugated diene polymer that satisfies the following conditions (1) to (6): (1) The molecular weight distribution curve obtained by gel permeation chromatography (GPC) measurement is unimodal, and has a shoulder in the region from the peak top of the molecular weight distribution curve to the peak end point on the high molecular weight side. (2) The weight average molecular weight (Mw) measured by GPC is 200,000 to 1,000,000. (3) The molecular weight distribution is 1.7 to 3.0. (4) The modification rate is less than 40% by mass.
  • GPC gel permeation chromatography
  • [1-2B] The conjugated diene polymer according to any one of [1] to [1-2A], wherein the weight average molecular weight (Mw) is 400,000 to 800,000.
  • Mw weight average molecular weight
  • [1-3A] The conjugated diene polymer according to any one of [1] to [1-2B], wherein the molecular weight distribution is 1.75 to 2.8.
  • [1-3B] The conjugated diene polymer according to any one of [1] to [1-3A], wherein the molecular weight distribution is 1.8 to 2.8.
  • [1-3C] The conjugated diene polymer according to any one of [1] to [1-3B], wherein the molecular weight distribution is 1.85 to 2.5.
  • [1-5A] The conjugated diene polymer according to any one of [1] to [1-4C], wherein the degree of branching (Bn) is 4 to 84.
  • [1-5B] The conjugated diene polymer according to any one of [1] to [1-5A], wherein the degree of branching (Bn) is 4 to 80.
  • [1-5C] The conjugated diene polymer according to any one of [1] to [1-5B], wherein the degree of branching (Bn) is 5 to 60.
  • [1-5D] The conjugated diene polymer according to any one of [1] to [1-5C], wherein the degree of branching (Bn) is 5 to 40.
  • [1-5E] The conjugated diene polymer according to any one of [1] to [1-5D], wherein the degree of branching (Bn) is 6 to 20.
  • [1-6A] The conjugated diene polymer according to any one of [1] to [1-5E], wherein the contraction factor (g') at the peak top molecular weight (Mp) is 0.91 or more.
  • [1-6B] The conjugated diene polymer according to any one of [1] to [1-6A], wherein the contraction factor (g') at the peak top molecular weight (Mp) is 0.92 or more.
  • [1-6C] The conjugated diene polymer according to any one of [1] to [1-6B], wherein the contraction factor (g') at the peak top molecular weight (Mp) is 2.00 or less.
  • [1-6D] The conjugated diene polymer according to any one of [1] to [1-6C], wherein the contraction factor (g') at the peak top molecular weight (Mp) is 1.50 or less.
  • [1-6E] The conjugated diene polymer according to any one of [1] to [1-6D], wherein the contraction factor (g') at the peak top molecular weight (Mp) is 1.00 or less.
  • [2] The conjugated diene polymer according to any one of [1] to [1-6E], wherein the shrinkage factor (g') of the number average molecular weight (Mn) obtained by GPC-light scattering measurement with a viscosity detector is 0.90 or more.
  • [2-1A] The conjugated diene polymer according to any one of [1] and [2], wherein the shrinkage factor (g') in the number average molecular weight (Mn) is 0.91 or more.
  • [2-1B] The conjugated diene polymer according to any one of [1] to [2-1A], wherein the shrinkage factor (g') in the number average molecular weight (Mn) is 0.92 or more.
  • [2-1C] The conjugated diene polymer according to any one of [1] to [2-1B], wherein the shrinkage factor (g') at the number average molecular weight (Mn) is 2.00 or less.
  • [2-1D] The conjugated diene polymer according to any one of [1] to [2-1C], wherein the shrinkage factor (g') at the number average molecular weight (Mn) is 1.50 or less.
  • [2-1E] The conjugated diene polymer according to any one of [1] to [2-1D], wherein the shrinkage factor (g') at the number average molecular weight (Mn) is 1.00 or less.
  • [2-2A] The conjugated diene-based polymer according to any one of [1] to [2-1E], wherein a shrinkage factor (g') at a peak top molecular weight (Mp) of the absolute molecular weight curve and a shrinkage factor (g') at the number average molecular weight (Mn) are 0.90 or more.
  • [2-2B] The conjugated diene-based polymer according to any one of [1] to [2-2A], wherein a shrinkage factor (g') at a peak top molecular weight (Mp) of the absolute molecular weight curve and a shrinkage factor (g') at the number average molecular weight (Mn) are 0.91 or more.
  • [2-2C] The conjugated diene-based polymer according to any one of [1] to [2-2B], wherein a shrinkage factor (g') at the peak top molecular weight (Mp) of the absolute molecular weight curve and a shrinkage factor (g') at the number average molecular weight (Mn) are 0.92 or more.
  • [2-3A] The conjugated diene-based polymer according to any one of [1] to [2-2C], wherein a shrinkage factor (g') at the peak top molecular weight (Mp) of the absolute molecular weight curve and a shrinkage factor (g') at the number average molecular weight (Mn) are 0.90 or more and 2.00 or less.
  • [2-3B] The conjugated diene-based polymer according to any one of [1] to [2-3A], wherein a shrinkage factor (g') at the peak top molecular weight (Mp) of the absolute molecular weight curve and a shrinkage factor (g') at the number average molecular weight (Mn) are 0.91 or more and 1.50 or less.
  • [2-3C] The conjugated diene-based polymer according to any one of [1] to [2-3B], wherein a shrinkage factor (g') at the peak top molecular weight (Mp) of the absolute molecular weight curve and a shrinkage factor (g') at the number average molecular weight (Mn) are 0.92 or more and 1.00 or less.
  • [3] The conjugated diene-based polymer according to any one of [1] to [2-3C], wherein the modification rate is less than 10% by mass.
  • [3-1] The conjugated diene-based polymer according to [3], wherein the modification rate is 5% by mass or less.
  • [3-2] The conjugated diene-based polymer according to [3] or [3-1], wherein the modification rate is 0% by mass.
  • the conjugated diene polymer (A) and the conjugated diene polymer (B) are obtained by continuously polymerizing each of them using one or more reactors, a polymer solution containing the conjugated diene polymer (A) and a polymer solution containing the conjugated diene polymer (B) are mixed together; and then removing the solvent to obtain a conjugated diene-based polymer.
  • a molded body comprising: [8-1] The molded body according to [8], wherein the content of the organic acid is 0.01 to 2.0 parts by mass.
  • a conjugated diene polymer can be obtained that exhibits excellent bale formability, excellent processability when vulcanized, and high hardness and excellent abrasion resistance when vulcanized, even in the case of an unextended product that does not contain process oil.
  • the present embodiment an embodiment of the present invention (hereinafter referred to as "the present embodiment") will be described in detail. It should be noted that the following embodiments are examples for explaining the present invention, and the present invention is not limited to the following embodiments, but can be implemented in various modified forms within the scope of the gist thereof.
  • the conjugated diene polymer of the present embodiment is the molecular weight distribution curve obtained by gel permeation chromatography (GPC) measurement is unimodal and has a shoulder in the region from the peak top of the molecular weight distribution curve to the end point of the peak on the high molecular weight side;
  • the weight average molecular weight (Mw) measured by GPC is 200,000 to 1,000,000, The molecular weight distribution is 1.7 or more and 3.0 or less, the modification rate is less than 40% by mass based on the total amount of the conjugated diene polymer,
  • Mw1 molecular weight distribution
  • Mw2 degree of branching (Bn) at the absolute molecular weight of (Mw1+Mw2)/2 is 4 or more;
  • the conjugated diene polymer of this embodiment may be a homopolymer of a single conjugated diene compound, a polymer (i.e., copolymer) of different types of conjugated diene compounds, or a copolymer of a conjugated diene compound and a vinyl aromatic compound.
  • Conjugated diene compounds include, but are not limited to, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-heptadiene. Of these, 1,3-butadiene and isoprene are preferred from the perspective of effectively and reliably achieving the effects of this embodiment. These conjugated diene compounds may be used alone or in combination of two or more.
  • vinyl aromatic compounds include, but are not limited to, styrene, p-methylstyrene, m-methylstyrene, o-methylstyrene, ⁇ -methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and diphenylethylene. Of these, styrene is preferred from the perspective of effectively and reliably achieving the effects of this embodiment. These vinyl aromatic compounds may be used alone or in combination of two or more.
  • the conjugated diene polymer may be a random copolymer or a block copolymer.
  • random copolymers include, but are not limited to, random copolymers composed of two or more conjugated diene compounds such as butadiene-isoprene random copolymers, butadiene-styrene random copolymers, isoprene-styrene random copolymers, and random copolymers composed of conjugated dienes and vinyl-substituted aromatic compounds such as butadiene-isoprene-styrene random copolymers.
  • the composition distribution of each monomer in the copolymer chain is not particularly limited, and examples thereof include a completely random copolymer having a composition close to a statistically random composition and a tapered (gradient) random copolymer having a composition distributed in a tapered shape.
  • the bonding mode of the conjugated diene i.e., the composition of 1,4-bonds, 1,2-bonds, etc., may be uniform or may have a distribution.
  • the conjugated diene polymer of this embodiment is specified to have a unimodal molecular weight distribution curve obtained by gel permeation chromatography (GPC) analysis, with a shoulder in the region from the peak top to the peak end point on the high molecular weight side.
  • GPC gel permeation chromatography
  • the molecular weight distribution curve is unimodal and has a shoulder in the region from the peak top to the peak end point on the high molecular weight side
  • the molecular weight distribution curve has one peak top and three or more inflection points between the peak start point and the peak end point, and that there are two or more inflection points in the region from the peak top to the peak end point, i.e., the region from the peak top to the high molecular weight side.
  • the number of shoulders is n
  • the number of inflection points is calculated from the formula 2n+1.
  • the conjugated diene polymer of the present embodiment has one or more shoulders and three or more inflection points in the region on the high molecular weight side from the peak top.
  • the upper limit of the number of shoulders is not particularly limited, but may be, for example, 5, 4, 3, or 2.
  • the following reasons can be cited as factors that result in good bale moldability, excellent processability when made into a vulcanizate, and good abrasion resistance when made into a vulcanizate, but the reasons are not limited to those described below.
  • the viscosity of the composition increases, making kneading more difficult, or the processability tends to deteriorate, with the result that the sheet becomes rough when formed after kneading and the sheet is more likely to break.
  • the conjugated diene polymer of this embodiment is characterized by its single-peaked molecular weight distribution curve, with a shoulder in the region from the peak top to the end point of the peak on the high molecular weight side. While containing a high molecular weight component (referred to as “Component A”), the polymer is primarily composed of a component (referred to as “Component B”) with a lower molecular weight than that component, resulting in excellent bale moldability. Furthermore, Component A improves the torque of the mixer when kneading with the filler, adequately dispersing the filler, while Component B reduces the viscosity of the composition, resulting in excellent processability.
  • Component A improves the torque of the mixer when kneading with the filler, adequately dispersing the filler
  • Component B reduces the viscosity of the composition, resulting in excellent processability.
  • Such a conjugated diene polymer having a single-peaked molecular weight distribution curve and a shoulder in the region from the peak top to the end point of the peak on the high molecular weight side can be obtained by mixing polymers consisting of components with different molecular weights and branching degrees, with the aim of achieving an appropriate balance between molecular weight and viscosity. Specifically, it can be obtained by adjusting the molecular weights, branching degrees, and ratios of Component A and Component B, as described below. This results in good bale moldability, excellent processability when vulcanized, and high hardness and good abrasion resistance when vulcanized.
  • the conjugated diene polymer of this embodiment has a weight average molecular weight measured by GPC measurement of preferably 20 x 10 4 or more, more preferably 30 x 10 4 or more, and even more preferably 40 x 10 4 or more.
  • the weight average molecular weight measured by GPC measurement is 20 x 10 4 or more, the torque of the mixer is well applied when kneading with a filler, and the filler tends to be easily dispersed.
  • the weight average molecular weight is preferably 100 x 10 4 or less, more preferably 90 x 10 4 or less, and even more preferably 80 x 10 4 or less.
  • the weight average molecular weight is 100 x 10 4 or less, the viscosity of the rubber composition when kneading with a filler does not become too high, and processability tends to be excellent.
  • the weight average molecular weight may be set within a range that combines any of the above upper and lower limits.
  • the weight average molecular weight of the conjugated diene polymer can be measured by the method described in the examples below.
  • the conjugated diene polymer of this embodiment has a number average molecular weight measured by GPC measurement of preferably 6 x 10 4 or more, more preferably 9 x 10 4 or more, and even more preferably 12 x 10 4 or more.
  • the number average molecular weight may be 15 x 10 4 or more.
  • the number average molecular weight is preferably 60 x 10 4 or less, more preferably 50 x 10 4 or less, even more preferably 45 x 10 4 or less, still more preferably 40 x 10 4 or less, still more preferably 35 x 10 4 or less, and most preferably 30 x 10 4 or less.
  • the number average molecular weight may be set within a range that combines any of the above upper and lower limits.
  • the number average molecular weight of the conjugated diene polymer can be measured by the method described in the examples below.
  • the ratio (Mw/Mn) of the weight average molecular weight (Mw) measured by GPC to the number average molecular weight (Mn) measured by GPC is preferably 1.7 or more, more preferably 1.75 or more, even more preferably 1.8 or more, still more preferably 1.85 or more, and most preferably 1.9 or more, from the viewpoints of processability during vulcanization and abrasion resistance of the vulcanizate.
  • the upper limit of the molecular weight distribution is not particularly limited, but is preferably 3.0 or less, more preferably 2.8 or less, and even more preferably 2.5 or less.
  • the molecular weight distribution of the conjugated diene polymer can be controlled within the above numerical range by adjusting the molecular weights and branching degrees of components A and B and the ratio thereof, as will be described later.
  • the conjugated diene polymer of the present embodiment may have a modifying group.
  • modifying group refers to a functional group that has affinity or bonding reactivity with the filler, and includes functional groups containing a nitrogen atom.
  • modification rate refers to the content, expressed in mass %, of a modified conjugated diene polymer component having a specific functional group in the polymer molecule that has affinity or binding reactivity with a filler relative to the total amount of the conjugated diene polymer mixture, when a mixture of a modified conjugated diene polymer and an unmodified conjugated diene polymer is obtained by modifying a conjugated diene polymer with a coupling modifier. Therefore, when the specific functional group contains a nitrogen atom, the term “modification rate” refers to the mass ratio of the nitrogen-containing conjugated diene polymer relative to the total amount of the conjugated diene polymer mixture.
  • conjugated diene polymer encompasses unmodified conjugated diene polymers and modified conjugated diene polymers.
  • conjugated diene polymer means an unmodified conjugated diene polymer.
  • the modification rate is the mass ratio of the modified conjugated diene polymer having a nitrogen atom-containing functional group resulting from the nitrogen atom-containing modifying agent to the total amount of the conjugated diene polymer.
  • the modification rate of the conjugated diene polymer of this embodiment is preferably less than 40% by mass, more preferably 30% by mass or less, even more preferably 20% by mass or less, even more preferably 10% by mass or less, still more preferably 5% by mass or less, and most preferably 0% by mass, relative to the total amount of the conjugated diene polymer. If the modification rate is 40% by mass or more, the amount of functional groups highly reactive with silica, particularly functional groups containing nitrogen atoms, will increase. This will lead to a reaction with the silica particles during the kneading process, increasing the viscosity of the composition and making kneading difficult.
  • a modification rate of less than 40% by mass results in excellent processability when vulcanized, and can prevent a decrease in hardness due to excessive dispersion of silica, particularly when forming a vulcanized product containing an inorganic filler such as silica.
  • the modification rate can be measured by chromatography, which can separate functional group-containing modified components from unmodified components.
  • chromatography can separate functional group-containing modified components from unmodified components.
  • methods using chromatography include a method (column adsorption GPC method) in which a gel permeation chromatography column filled with a polar substance such as silica that adsorbs specific functional groups is used, and the unadsorbed components are quantified using an internal standard for comparison.
  • the modification rate can be obtained by calculating the amount adsorbed to the silica-based column from the difference between a chromatogram obtained by measuring a sample solution containing the sample and low-molecular-weight internal standard polystyrene on a polystyrene-based gel column and a chromatogram obtained by measuring the same sample solution on a silica-based column.
  • the modification rate can be measured by the method described in the Examples below.
  • the modification rate can be controlled within the above-mentioned numerical range by adjusting the ratio of Components A and B, the amount of coupling modifier added in the polymerization of Components A and B, and the method of reacting the conjugated diene compound with the modifier.
  • components A and B may be obtained by combining a method of polymerization using an organolithium compound having at least one nitrogen atom in the molecule as a polymerization initiator, as described below, a method of copolymerizing a monomer having at least one nitrogen atom in the molecule, and a method of using a modifier having a structural formula described below, and then adjusting the ratio between them.
  • the conjugated diene polymer of the present embodiment has a nitrogen content of preferably 100 ppm or less, more preferably 50 ppm or less, even more preferably 30 ppm or less, still more preferably 20 ppm or less, still more preferably 10 ppm or less, and most preferably 0 ppm.
  • the nitrogen content is 100 ppm or less, the viscosity of the composition does not increase excessively even when the reaction with silica particles proceeds during the kneading step, so kneading is easy, the sheet surface after kneading is good, and processability tends to be excellent.
  • the nitrogen content can be controlled within the above-mentioned range by appropriately adjusting the ratio of components A and B, the ratio of nitrogen contained in the modifier in the polymerization of components A and B, the amount of nitrogen-containing modifier added, and the amount of modifier bonded to the polymerization terminals.
  • the conjugated diene polymer of the present embodiment preferably has a silicon content of 1 ppm or more and 200 ppm or less.
  • the silicon content is 1 ppm or more, in a rubber composition in which the conjugated diene polymer of this embodiment is mixed with a reinforcing material, the interaction between the conjugated diene polymer and the reinforcing material is strengthened, and when vulcanized, the rubber composition tends to have excellent fracture strength and wear resistance.
  • the silicon content of the conjugated diene polymer of the present embodiment is more preferably 2 ppm or more, even more preferably 3 ppm or more, even more preferably 4 ppm or more, and most preferably 5 ppm or more.
  • the silicon content of the conjugated diene polymer of this embodiment is more preferably 150 ppm or less, even more preferably 100 ppm or less, even more preferably 50 ppm or less, and most preferably 30 ppm or less.
  • the silicon content can be controlled within the above range by adjusting the ratio of Components A and B, or by carrying out a coupling reaction using a silicon-containing coupling agent in the polymerization of Components A and B and adjusting the amount of the silicon-containing coupling agent added.
  • the microstructure of a conjugated diene polymer affects the glass transition temperature of the conjugated diene polymer, and therefore the amount of bound vinyl aromatic monomer units and the amount of vinyl bonds have preferred ranges from the viewpoint of controlling the glass transition temperature.
  • the amount of bound vinyl aromatic monomer units in the microstructure of a conjugated diene polymer is not particularly limited, but is preferably 0% by mass or more and 30% by mass or less, more preferably 1% by mass or more and 28% by mass or less, and even more preferably 5% by mass or more and 25% by mass or less, based on the total conjugated diene polymer.
  • the amount of bound vinyl aromatic monomer units is within the above range, the vulcanizate of the conjugated diene polymer tends to have even better fracture strength, abrasion resistance, and low hysteresis loss.
  • an increase in the amount of bound vinyl aromatic monomer units tends to increase the Tg of the conjugated diene polymer, while a decrease in the amount of bound vinyl aromatic monomer units tends to decrease the Tg.
  • the term "amount of bound vinyl aromatic monomer units" refers to the content of the portion derived from the aromatic vinyl compound used as a monomer.
  • the amount of bound conjugated diene monomer units is not particularly limited, but is preferably 70% by mass or more and 100% by mass or less, more preferably 72% by mass or more and 99% by mass or less, and even more preferably 75% by mass or more and 95% by mass or less, relative to the entire conjugated diene polymer.
  • the amount of bound conjugated diene monomer units is within the above range, the vulcanized product of the conjugated diene polymer tends to have even better breaking strength, abrasion resistance, and low hysteresis loss.
  • “amount of bound conjugated diene monomer units” refers to the content of the portion derived from the conjugated diene compound used as a monomer.
  • the amount of vinyl bonds in the bound conjugated diene monomer units is not particularly limited, but is preferably 10 mol% to 60 mol% of the total bound conjugated diene monomer units, more preferably 11 mol% to 40 mol%, even more preferably 12 mol% to 35 mol%, still more preferably 13 mol% to 30 mol%, even more preferably 14 mol% to 29 mol%, and particularly preferably 15 mol% to 28 mol%.
  • the conjugated diene polymer tends to have better fracture strength and abrasion resistance due to increased linearity of the conjugated diene moiety structure and stronger entanglement of polymer chains. Furthermore, when the vinyl bond amount is within the above range, the vulcanizate thereof tends to have even lower hysteresis loss.
  • the term "vinyl bond content in a linked conjugated diene monomer unit" refers to the proportion of a portion having a vinyl bond among portions derived from a conjugated diene compound used as a monomer (hereinafter referred to as "linked conjugated diene monomer units").
  • branched polymers tend to have smaller molecular size compared to linear polymers with the same absolute molecular weight.
  • “molecular size” refers to the volume that the molecule substantially occupies.
  • the shrinkage factor (g') represents the relative molecular size of the target polymer and is an indicator of the ratio of the molecular size of the target polymer to the molecular size of a linear polymer with the same absolute molecular weight. In other words, if the degree of branching of a polymer is high, its size will be relatively small, and therefore the shrinkage factor (g') will tend to be small.
  • the shrinkage factor (g') is defined as the ratio of the intrinsic viscosity [ ⁇ ] of the target polymer to the intrinsic viscosity [ ⁇ ] of a linear polymer having the same absolute molecular weight as the target polymer ([ ⁇ ]/[ ⁇ ]).
  • M is the absolute molecular weight. Therefore, the shrinkage factor (g') and degree of branching (Bn) can be determined by measuring the absolute molecular weight and intrinsic viscosity of the target polymer using a GPC-light scattering measurement method with a viscosity detector.
  • the calculated degree of branching (Bn) accurately represents the number of polymer chains that are directly or indirectly bonded to each other with respect to the longest polymer main chain.
  • absolute molecular weight refers to the molecular weight measured by light scattering.
  • branched polymers generally tend to have smaller molecular sizes compared to linear polymers with the same absolute molecular weight. Therefore, GPC measurement, which determines molecular weight by screening polymers based on molecular size and comparing them with standard polystyrene samples, tends to underestimate the molecular weight of polymers with branched structures.
  • light scattering measures molecular weight by directly observing the molecules. Therefore, light scattering can accurately measure molecular weight without being affected by the influence of polymer structure or interactions with column packing materials. Absolute molecular weight can be measured by the method described in the examples below.
  • intrinsic viscosity ideally means the viscosity [ ⁇ ] calculated by the following formula (I):
  • ⁇ 1 represents the viscosity when the target polymer is dissolved in a solvent at a concentration c
  • ⁇ 2 represents the viscosity of the solvent.
  • the intrinsic viscosity is a value measured by the method described in the Examples section below.
  • the above shrinkage factors represent the rate of reduction in molecular size and do not accurately represent the branched structure of the polymer.
  • the degree of branching (Bn) of the modified conjugated diene polymer is calculated using the value of the shrinkage factor (g') at each absolute molecular weight of the modified conjugated diene polymer.
  • the calculated "degree of branching (Bn)" accurately represents the number of polymers that are directly or indirectly bonded to each other in the longest main chain structure.
  • the calculated branching degree (Bn) is an index that expresses the branching structure of a modified conjugated diene polymer. For example, in the case of a typical four-branched star polymer (four polymer chains connected to the center), two polymer chain arms are connected to the longest highly branched main chain structure, and the branching degree (Bn) is evaluated as 2.
  • branching refers to a structure formed by one polymer being directly or indirectly bonded to another polymer.
  • degree of branching (Bn) refers to the number of polymers that are directly or indirectly bonded to the longest main chain structure. In other words, it takes into account not only the side chains bonded to the longest polymer chain, but also the number of branches in those side chains if those side chains are further branched. Therefore, if one polymer chain is bonded to the longest polymer chain as a side chain, and another polymer chain is further bonded to that side chain, the degree of branching is 2.
  • the branching degree (Bn) at the absolute molecular weight of (Mw1+Mw2)/2 is preferably 4 or more, more preferably 5 or more, and even more preferably 6 or more.
  • the polymer When the branching degree (Bn) at the absolute molecular weight of (Mw1+Mw2)/2 is 4 or more, the polymer has good bale moldability, excellent processability when vulcanized, and a torque of a mixer can be easily applied when kneading with a filler, which tends to facilitate dispersion of the filler in a short time.
  • peak end point refers to the point at which the absolute molecular weight is highest as measured by GPC-light scattering with a viscosity detector.
  • the conjugated diene polymer of this embodiment has a branching degree (Bn) of 4 or more at the absolute molecular weight of (Mw1 + Mw2)/2, the increase in viscosity when vulcanized due to an increase in absolute molecular weight is suppressed.
  • Bn branching degree
  • the torque of the mixer is easily applied when kneading with a filler such as silica, the polymer is thoroughly mixed with the silica during the kneading process, making it possible to disperse the silica.
  • the absolute molecular weight of the conjugated diene polymer can be measured by the method described in the examples below.
  • the upper limit of the degree of branching (Bn) is not particularly limited and may be equal to or higher than the detection limit, but is preferably 84 or less, more preferably 80 or less, even more preferably 60 or less, particularly preferably 40 or less, and even more preferably 20 or less.
  • the conjugated diene polymer of the present embodiment has a degree of branching (Bn) of 84 or less, and therefore tends to have excellent abrasion resistance when vulcanized.
  • the degree of branching of the conjugated diene polymer can be controlled by the number of functional groups of the branching agent, the amount of branching agent added, the timing of adding the branching agent, and the number of functional groups of the coupling agent or nitrogen-containing modifier, and the amount of coupling agent or nitrogen-containing modifier added. More specific details are described below in the method for producing a conjugated diene polymer.
  • the abrasion resistance and breaking strength of a polymer tend to improve as the absolute molecular weight of the polymer increases.
  • the absolute molecular weight of a polymer with a low degree of branching is increased, polymer particles tend to peel off easily from the surface of the bale, worsening bale formability.
  • the viscosity during vulcanization increases significantly, which tends to significantly worsen processability during vulcanization. Therefore, with polymers with a low degree of branching, silica cannot be sufficiently dispersed in the polymer during the kneading process. As a result, processability constraints limit the degree of freedom in molecular weight design.
  • the conjugated diene polymer of this embodiment preferably has a shrinkage factor (g') at the peak top molecular weight (Mp) obtained by GPC-light scattering measurement with a viscosity detector of 0.90 or more, more preferably 0.91 or more, and even more preferably 0.92 or more.
  • a shrinkage factor (g') at the peak top molecular weight (Mp) is 0.90 or more, the number of free ends is reduced, which suppresses energy loss and tends to result in excellent fuel-saving performance.
  • the upper limit of the shrinkage factor (g') at the peak top molecular weight (Mp) is not particularly limited, but may be, for example, 2.00, 1.50, or 1.00.
  • the above-mentioned lower and upper limits of the shrinkage factor (g') at the peak top molecular weight (Mp) may be appropriately combined to define a numerical range, such as 0.90 to 2.00, 0.91 to 1.50, or 0.92 to 1.00.
  • the conjugated diene polymer of this embodiment preferably has a shrinkage factor (g') of 0.90 or more, more preferably 0.91 or more, and even more preferably 0.92 or more, in terms of the number average molecular weight (Mn) obtained by GPC-light scattering measurement with a viscosity detector.
  • a shrinkage factor (g') of 0.90 or more in terms of the number average molecular weight (Mn) is 0.90 or more, the number of free ends is reduced, which tends to suppress energy loss and result in excellent fuel-saving performance.
  • the upper limit of the shrinkage factor (g') in the number average molecular weight (Mn) is not particularly limited, but may be, for example, 2.00, 1.50, or 1.00.
  • the above-mentioned lower and upper limits of the shrinkage factor (g') in the number average molecular weight (Mn) may be appropriately combined to define a numerical range, such as 0.90 to 2.00, 0.91 to 1.50, or 0.92 to 1.00.
  • the shrinkage factor (g') at the peak top molecular weight (Mp) and the shrinkage factor (g') at the number average molecular weight (Mn) are both preferably 0.90 or more, more preferably 0.91 or more, and even more preferably 0.92 or more.
  • the shrinkage factor (g') at the peak top molecular weight (Mp) and the shrinkage factor (g') at the number average molecular weight (Mn) may both be 0.90 to 2.00, 0.91 to 1.50, or 0.92 to 1.00.
  • the Mooney viscosity is an index showing the overall characteristics of a conjugated diene polymer, including information on the molecular weight, molecular weight distribution, degree of branching, and content of a softener of the conjugated diene polymer.
  • the method for measuring the Mooney viscosity is specified in ISO 289, and the measurement error due to differences between instruments is small, making it extremely effective in controlling the performance of the conjugated diene polymer.
  • the conjugated diene polymer of the present embodiment has a Mooney viscosity measured at 100°C (hereinafter also simply referred to as "Mooney viscosity" or "ML”) of preferably 20 or more, more preferably 30 or more, and even more preferably 40 or more, from the viewpoints of handling stability, breaking strength, and abrasion resistance when a rubber composition for crosslinking containing the conjugated diene polymer of the present embodiment is used in a tire.
  • Mooney viscosity measured at 100°C
  • the upper limit is preferably 170 or less, and from the viewpoints of moldability and productivity of molded articles of various shapes such as sheet-like or block-like shapes, and rubber compositions containing the conjugated diene-based polymer of this embodiment, and processability of rubber compositions blended with fillers and the like, it is more preferably 160 or less, even more preferably 150 or less, and particularly preferably 145 or less.
  • the Mooney viscosity of a conjugated diene polymer is measured by using a sample of the conjugated diene polymer formed into a plate shape by a pressure press, setting the sample in a measuring device, preheating the sample at 100°C for 1 minute, rotating the rotor at 2 rpm, and measuring the torque after 4 minutes, and the measured value is taken as the Mooney viscosity (ML (1+4) ).
  • the Mooney viscosity of the conjugated diene polymer of the present embodiment can be controlled within the above-mentioned range by adjusting the type, timing of use, and amount of the branching agent and coupling modifier, the molecular weight, molecular weight distribution, and degree of branching of the conjugated diene polymer, and adjusting the ratio of A to B, for each of Components A and B.
  • the conjugated diene polymer of this embodiment has a Mooney relaxation rate (hereinafter also simply referred to as "Mooney relaxation rate” or “MSR”) measured at 100°C of preferably 0.9 or less, more preferably 0.8 or less and even more preferably 0.75 or less from the viewpoint of processability of a rubber composition obtained by blending a filler or the like with the conjugated diene polymer.
  • MSR Mooney relaxation rate
  • the Mooney relaxation rate is preferably 0.25 or more, more preferably 0.28 or more and even more preferably 0.30 or more from the viewpoint of handling stability and breaking strength when the conjugated diene polymer of this embodiment is used as a tire material.
  • the Mooney relaxation coefficient is also affected by the molecular weight, molecular weight distribution, degree of branching, and softener content of the conjugated diene polymer, and is an index showing the overall characteristics of the conjugated diene polymer.
  • the MSR can be measured using a Mooney viscometer as follows.
  • the Mooney relaxation rate was measured by first preheating the sample at 100°C for 1 minute, rotating the rotor at 2 rpm, measuring the Mooney viscosity (ML (1+4) ) from the torque after 4 minutes, and then immediately stopping the rotor rotation.
  • the torque was recorded in Mooney units every 0.1 seconds from 1.6 seconds to 5 seconds after the rotor rotation was stopped, and the slope of the straight line obtained by plotting the torque versus time (seconds) logarithmically was determined, and the absolute value of this slope was taken as the Mooney relaxation rate (MSR).
  • the Mooney relaxation coefficient of the conjugated diene polymer of the present embodiment can be controlled within the above-mentioned range by adjusting the type, timing of use, and amount of the branching agent and coupling modifier, the molecular weight, molecular weight distribution, and degree of branching of the conjugated diene polymer, and adjusting the ratio of A to B, for each of components A and B.
  • the molded article of this embodiment is a molded article containing the conjugated diene-based polymer of this embodiment described above. From the viewpoint of handleability, it is preferably a sheet-like or block-like molded article.
  • the size and thickness of the sheet-like or block-like molded product are not particularly limited, but examples include a sheet-like molded product having a thickness of about 1 cm and a rectangular or cubic block-like molded product having a size of 1,000 cm 3 .
  • the molded product of this embodiment is preferably a block-shaped molded product, and the block shape is preferably a roughly rectangular parallelepiped, and more preferably a block-shaped (bale) molded product of 1,000 cm or more . Furthermore, a rectangular parallelepiped bale weighing 17.5 kg to 35 kg is even more preferable.
  • a preferred molding method is to prepare crumbs having a specific surface area of 0.7 m 2 /g to 3.2 m 2 /g and then compression mold the crumbs. From the viewpoint of moldability, it is preferable to further carry out a step of sieving the crumbs before molding. Since the crumbs adhere to each other when they are compression molded, the specific surface area of the molded body becomes smaller than the specific surface area of the crumbs.
  • the adhesion of the crumbs during compression molding can be adjusted by the molecular weight, composition, and structure of the conjugated diene polymer, the softener component composition, and the temperature and pressure during compression.
  • the molecular weight of the conjugated diene polymer when it is desired to increase the adhesion of the crumbs and decrease the specific surface area of the bale, it is preferable to decrease the molecular weight of the conjugated diene polymer, increase the amount of the softener component, and increase the temperature and pressure during compression.
  • the specific surface area of the molded body of this embodiment is preferably 0.005 to 0.05 m 2 /g, and more preferably 0.01 to 0.04 m 2 /g from the viewpoint of film packaging.
  • a specific surface area of 0.005 m 2 /g or more of the molded body suppresses bale expansion, and a specific surface area of 0.05 m 2 /g or less of the molded body is preferred because it reduces crumb peeling from the molded body.
  • the specific surface area of the molded body can be determined by the BET method. Generally, the specific surface area of a large-sized molded body may vary depending on the location, so it is preferable to collect the sample from near the center of the molded body.
  • the crumbs are preferably sieved according to particle size and then mixed in an appropriate ratio. If the specific surface area of the molded body formed using the crumbs after solvent removal exceeds the upper limit of the above range, it is preferable to increase the composition of large crumbs and decrease the composition of small crumbs among the sieved crumbs, and if it does not reach the lower limit, it is preferable to decrease the composition of large crumbs and increase the composition of small crumbs.
  • the molding compression pressure for the molded body is preferably 3 MPa to 30 MPa, and more preferably 10 MPa to 20 MPa.
  • a molding compression pressure of 30 MPa or less allows for a compact design of the equipment, resulting in good installation efficiency, while a molding compression pressure of 3 MPa or more results in good moldability.
  • Good moldability means that the surface of the molded body is smooth, there is no polymer peeling after the molding process, and expansion after molding tends to be suppressed.
  • the temperature of the conjugated diene polymer or the rubber composition containing the conjugated diene polymer during molding is preferably 30 to 120°C, more preferably 50 to 100°C from the viewpoint of reducing residual solvent and suppressing thermal degradation.
  • a molding temperature of 30° C. or higher provides good moldability, while a temperature of 120° C. or lower is preferred because gel formation due to thermal degradation of the rubber composition can be suppressed.
  • the higher the temperature and pressure during molding the smaller the specific surface area of the bale.
  • the pressure retention time during molding is preferably 3 to 30 seconds, more preferably 5 to 20 seconds. When the pressure retention time during compression is 30 seconds or less, production efficiency is good, and when it is 5 seconds or more, moldability is good.
  • the resin type of the film may be, for example, polyethylene, ethylene copolymer resin, polystyrene, high impact polystyrene, or PET. From the viewpoint of ease of handling during transportation of the molded article and preventing condensation from forming in the gap between the packaging sheet and the bale, it is preferable that the packaging sheet has good adhesion.
  • the molded article of the present embodiment is used, for example, for storage in a container for transportation. If the expansion rate of the molded article one day after molding is less than 5%, the molded article has good storage properties in the container, which is preferable.
  • a softener component which will be described later, may be added to a sheet- or block-shaped molded product using the conjugated diene polymer of this embodiment.
  • the amount of the softener component is preferably 2 parts by mass or less, more preferably 1.5 parts by mass or less, even more preferably 1 part by mass or less, even more preferably less than 1 part by mass, per 100 parts by mass of the conjugated diene polymer, and it is most preferable that no softener component is added.
  • the softener component used in the production of the rubber composition described below may be referred to as a "rubber softener,” but this is merely a literal distinction from the softener component used in the molded article of the conjugated diene polymer, and does not distinguish between the materials themselves.
  • the molded article of this embodiment may contain an organic acid in addition to the conjugated diene polymer of this embodiment described above.
  • the organic acid is not particularly limited as long as it is a compound having an acidic group and a hydrocarbon group.
  • the acidic group include a carboxy group, a sulfo group, a hydroxyl group, and a group derived from a phosphate ester.
  • the organic acid is preferably a compound that does not have a group derived from a phosphate ester and has a carboxy group.
  • organic carboxylic acids such as aliphatic carboxylic acids and aliphatic hydroxycarboxylic acid compounds can be suitably used.
  • Aliphatic carboxylic acids can be compounds having a hydrocarbon group having 2 to 30 carbon atoms and a carboxy group.
  • aliphatic carboxylic acids include saturated aliphatic carboxylic acids such as acetic acid, octanoic acid, decanoic acid, undecylic acid, lauric acid, tridecylic acid, myristic acid, pentadecylic acid, palmitic acid, heptadecanoic acid, stearic acid, nonadecylic acid, and arachidic acid; and unsaturated aliphatic carboxylic acids such as palmitoleic acid, oleic acid, ricinoleic acid, linoleic acid, linolenic acid, myristoleic acid, arachidonic acid, eicosapentaenoic acid, and docosahexaenoic acid.
  • Stearic acid is preferred due to its availability.
  • Aliphatic compounds having a hydroxyl group and a carboxyl group can be used as the aliphatic hydroxycarboxylic acid compound.
  • the aliphatic hydroxycarboxylic acid compound preferably has a linear hydrocarbon group, and the hydrocarbon group may have an unsaturated bond. If an unsaturated bond is present, the trans form is preferred.
  • the number of carbon atoms in the aliphatic hydroxycarboxylic acid compound is preferably 2 to 40, and more preferably 8 to 30.
  • aliphatic hydroxycarboxylic acid compounds include hydroxycaprylic acid, hydroxylauric acid, hydroxypalmitic acid, hydroxystearic acid, dihydroxystearic acid, and hydroxyelaidic acid. Because they can further suppress cold flow, the aliphatic hydroxycarboxylic acid compound is preferably 12-hydroxystearic acid or 2-hydroxycaprylic acid, and more preferably 12-hydroxystearic acid.
  • the process for obtaining a molded article containing the conjugated diene polymer of this embodiment includes a step of removing the solvent from a conjugated diene polymer solution to obtain conjugated diene polymer crumbs.
  • the method for removing the solvent from the conjugated diene polymer solution is not particularly limited, but examples include known desolvation methods such as steam stripping, and drying procedures such as heat treatment using a dehydrating extruder, a drying extruder, or a conveyor.
  • the content of the organic acid is preferably 0.01 parts by mass or more, more preferably 0.02 parts by mass or more, even more preferably 0.03 parts by mass or more, and particularly preferably 0.04 parts by mass or more, relative to 100 parts by mass of the conjugated diene-based polymer.
  • the content of the organic acid is high, the thermal stability of the crumbs tends to decrease, increasing the risk of fire during the drying step.
  • the content is preferably 2.0 parts by mass or less, more preferably 1.5 parts by mass or less, even more preferably 1.0 part by mass or less, and particularly preferably 0.5 parts by mass or less, relative to 100 parts by mass of the conjugated diene-based polymer.
  • the above upper and lower limits of the organic acid content may be appropriately combined to define any range.
  • the organic acid content may be 0.01 to 2.0 parts by mass, 0.02 to 1.5 parts by mass, 0.03 to 1.0 part by mass, or 0.04 to 0.5 parts by mass per 100 parts by mass of the conjugated diene polymer.
  • the conjugated diene polymer of the present embodiment can be obtained by continuously polymerizing the conjugated diene polymer (A) and the conjugated diene polymer (B) using one or more reactors, respectively, mixing the respective polymer solutions, and then removing the solvent.
  • the production method is not limited as long as the conjugated diene polymer has a unimodal molecular weight distribution curve obtained by gel permeation chromatography (GPC) measurement and has a shoulder in the region from the peak top of the molecular weight distribution curve to the end point of the peak on the high molecular weight side.
  • GPC gel permeation chromatography
  • the conjugated diene polymer (A) has a weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of 50 ⁇ 10 4 or more and 300 ⁇ 10 4 or less, and the conjugated diene polymer (B) has a Mw measured by GPC of 10 ⁇ 10 4 or more and 50 ⁇ 10 4 or less.
  • Mw weight average molecular weight measured by gel permeation chromatography
  • the weight average molecular weight (Mw) of the conjugated diene polymer (A) is 50 ⁇ 10 4 or more and 300 ⁇ 10 4 or less, preferably 60 ⁇ 10 4 or more and 200 ⁇ 10 4 or less, and more preferably 700 ⁇ 10 4 or more and 150 ⁇ 10 4 or less. From the viewpoint of abrasion resistance when vulcanized, it is 50 ⁇ 10 4 or more, and from the viewpoint of the balance between processability when vulcanized and abrasion resistance when vulcanized, it is 300 ⁇ 10 4 or less, and preferably 150 ⁇ 10 4 or less.
  • the weight average molecular weight (Mw) of the conjugated diene polymer (B) is 10 ⁇ 10 4 or more and 50 ⁇ 10 4 or less, preferably 15 ⁇ 10 4 or more and 40 ⁇ 10 4 or less, and more preferably 20 ⁇ 10 4 or more and 30 ⁇ 10 4 or less. From the viewpoint of abrasion resistance when vulcanized, it is 10 ⁇ 10 4 or more, and from the viewpoint of the balance between processability when vulcanized and abrasion resistance when vulcanized, it is 50 ⁇ 10 4 or less, preferably 30 ⁇ 10 4 or less.
  • the difference in weight average molecular weight (Mw) between the conjugated diene polymer (A) and the conjugated diene polymer (B), ⁇ Mw, is preferably 20 ⁇ 10 4 or more, more preferably 30 ⁇ 10 4 or more, even more preferably 40 ⁇ 10 4 or more, and still more preferably 50 ⁇ 10 4 or more.
  • the upper limit of ⁇ Mw is not particularly limited, and may be, for example, 200 ⁇ 10 4 , 150 ⁇ 10 4 , 100 ⁇ 10 4 , or 80 ⁇ 10 4 . When the content is within this range, there tends to be an excellent balance between processability when vulcanized and abrasion resistance when vulcanized.
  • Abrasion resistance tends to be better as the molecular weight increases, while processability tends to be better as the molecular weight decreases.
  • the conjugated diene polymer (A) will be a conjugated diene polymer that is more specialized in abrasion resistance
  • the conjugated diene polymer (B) will be a modified conjugated diene polymer that is more specialized in processability.
  • the weight average molecular weight (Mw) of the conjugated diene polymers (A) and (B) can be controlled by adjusting the polymerization temperature, the amount of monomer added, and the amount of polymerization initiator added in each polymerization step. Increasing the polymerization temperature in the polymerization step increases the polymerization reaction rate and tends to produce a polymer with a large weight-average molecular weight. However, if the polymerization temperature is too high, deactivation of the polymer terminals due to heat tends to occur, and the weight-average molecular weight of the conjugated diene polymer tends to be difficult to increase.
  • the weight-average molecular weight difference ( ⁇ Mw) between the conjugated diene polymers (A) and (B) can be controlled within the above-mentioned range by appropriately adjusting the conditions in the polymerization step of the conjugated diene polymer (A) and/or the modified conjugated diene polymer (B).
  • ⁇ Polymerization process> In the polymerization step of the conjugated diene polymers (A) and (B), at least a conjugated diene compound is polymerized using an organolithium compound as a polymerization initiator to obtain a conjugated diene polymer.
  • the polymerization step at least a conjugated diene compound is polymerized, and if necessary, the polymerization step may include copolymerization of the conjugated diene compound with an aromatic vinyl compound, a step of adding a branching agent to obtain a conjugated diene-based polymer having a branched structure (hereinafter, these steps may be collectively referred to as a polymerization branching step), and a step of adding a coupling modifier.
  • the conjugated diene compound is not particularly limited as long as it is a polymerizable monomer, but a conjugated diene compound containing 4 to 12 carbon atoms per molecule is preferred, and a conjugated diene compound containing 4 to 8 carbon atoms is more preferred.
  • Examples of such conjugated diene compounds include, but are not limited to, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 3-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-heptadiene.
  • 1,3-butadiene and isoprene are preferred from the viewpoint of ease of industrial availability. These may be used alone or in combination of two or more.
  • the aromatic vinyl compound is not particularly limited as long as it is a monomer copolymerizable with a conjugated diene compound, but a monovinyl aromatic compound is preferred.
  • monovinyl aromatic compounds include, but are not limited to, styrene, p-methylstyrene, ⁇ -methylstyrene, vinylethylbenzene, vinylxylene, vinylnaphthalene, and diphenylethylene.
  • styrene is preferred from the viewpoint of industrial availability. These compounds may be used alone or in combination of two or more.
  • the polymerization reaction of the conjugated diene compound and aromatic vinyl compound is preferably a propagation reaction due to a living anionic polymerization reaction, which allows for the production of a conjugated diene polymer with an active terminal.
  • a branching agent when a branching agent is added, the conjugated diene polymer reacts efficiently with the branching agent. Furthermore, even when a coupling step, as described below, is included, this tends to result in a highly efficient reaction.
  • Polymerization reaction modes include, but are not limited to, batch (hereinafter also referred to as “batch”) and continuous polymerization reaction modes.
  • Continuous reactors include, for example, tank-type or tubular reactors equipped with a stirrer.
  • the monomer, an inert solvent (described below), and a polymerization initiator (described below) are continuously fed into the reactor, a polymer solution containing a polymer is obtained in the reactor, and the polymer solution is continuously discharged.
  • a batch reactor for example, a tank-type reactor equipped with a stirrer is used.
  • the monomer, an inert solvent described below, and a polymerization initiator described below are fed, and if necessary, the monomer is added continuously or intermittently during polymerization, to obtain a polymer solution containing a polymer in the reactor, which is then discharged after polymerization is complete.
  • conjugated diene polymer (A) and conjugated diene polymer (B) from the viewpoint of obtaining conjugated diene polymers having active ends in a high proportion, it is preferable to carry out the polymerization reaction in a continuous polymerization reaction mode in which the polymer is continuously discharged and can be subjected to the next reaction in a short period of time.
  • the conjugated diene polymer obtained in the polymerization process may be a random copolymer or a block copolymer.
  • the random copolymer examples include, but are not limited to, a random copolymer composed of two or more conjugated diene compounds such as a butadiene-isoprene random copolymer, a butadiene-styrene random copolymer, an isoprene-styrene random copolymer, and a butadiene-isoprene-styrene random copolymer, each composed of a conjugated diene compound and an aromatic vinyl compound.
  • a random copolymer composed of two or more conjugated diene compounds such as a butadiene-isoprene random copolymer, a butadiene-styrene random copolymer, an isoprene-styrene random copolymer, and a butadiene-isoprene-styrene random copolymer, each composed of a conjugated diene compound and an aromatic vinyl compound.
  • the composition distribution of each monomer in the copolymer chain is not particularly limited, and examples thereof include a completely random copolymer having a composition close to a statistically random composition and a tapered (gradient) random copolymer having a composition distributed in a tapered shape.
  • the bonding mode of the conjugated diene i.e., the composition of 1,4-bonds, 1,2-bonds, etc., may be uniform or may have a distribution.
  • Block copolymers include, but are not limited to, type 2 block copolymers (diblock) consisting of two blocks, type 3 block copolymers (triblock) consisting of three blocks, and type 4 block copolymers (tetrablock) consisting of four blocks.
  • the polymer constituting one block may be a polymer consisting of one type of monomer, or a copolymer consisting of two or more types of monomers.
  • a polymer block consisting of 1,3-butadiene is represented by "B”
  • a copolymer of 1,3-butadiene and isoprene is represented by "B/I”
  • a copolymer of 1,3-butadiene and styrene is represented by "B/S”
  • a polymer block consisting of styrene is represented by "S”
  • these copolymers may be represented as B-B/I2 block copolymers, B-B/S2 block copolymers, S-B2 block copolymers, B-B/S-S3 block copolymers, S-B-S3 block copolymers, S-B-S-B4 block copolymers, etc.
  • each block does not necessarily need to be clearly distinguished.
  • a and B may be distributed uniformly or in a tapered pattern within the block.
  • the polymerization process for the conjugated diene polymer (A) and the conjugated diene polymer (B) may include a polymerization branching step.
  • the polymerization-branching step is a step of obtaining a conjugated diene polymer having a branched structure by polymerizing at least a conjugated diene compound, optionally together with a vinyl aromatic compound, using a polymerization initiator such as an organolithium compound described below, while adding a branching agent. Therefore, in the polymerization-branching step, the polymerization reaction of at least the conjugated diene compound and the aromatic vinyl compound is the main reaction before the branching agent is added, and the branching reaction starts after the branching agent is added.
  • conjugated diene compound and vinyl aromatic compound which are the monomers used in the polymerization step
  • at least one of the above-mentioned conjugated diene compounds and at least one of the above-mentioned vinyl aromatic compounds may be used.
  • derivatives of the above-mentioned conjugated diene compound or vinyl aromatic compound substituted to have at least one nitrogen atom in the molecule may also be used.
  • the polymerization initiator is not particularly limited, but for example, an organolithium compound such as an organomonolithium compound can be used.
  • Organomonolithium compounds include, for example, compounds having a carbon-lithium bond, a nitrogen-lithium bond, and a tin-lithium bond in terms of the bonding mode between the organic group and the lithium.
  • the organic monolithium compound is preferably an organic lithium compound having at least one nitrogen atom in the molecule, and more preferably an alkyllithium compound having a substituted amino group or a dialkylaminolithium.
  • a substituted amino group is an amino group that does not have an active hydrogen, or an amino group in which the active hydrogen is protected.
  • alkyllithium compound having an amino group without active hydrogen examples include, but are not limited to, piperidinolithium, 3-dimethylaminopropyllithium, 3-diethylaminopropyllithium, 4-(methylpropylamino)butyllithium, and 4-hexamethyleneiminobutyllithium.
  • alkyllithium compounds having an amino group with an active hydrogen protected include, but are not limited to, 3-bistrimethylsilylaminopropyllithium and 4-trimethylsilylmethylaminobutyllithium.
  • Dialkylaminolithiums include, but are not limited to, lithium dimethylamide, lithium diethylamide, lithium dipropylamide, lithium dibutylamide, lithium di-n-hexylamide, lithium diheptylamide, lithium diisopropylamide, lithium dioctylamide, lithium di-2-ethylhexylamide, lithium didecylamide, lithium ethylpropylamide, lithium ethylbutylamide, lithium ethylbenzylamide, lithium methylphenethylamide, lithium hexamethyleneimide, lithium pyrrolidide, lithium piperidide, lithium heptamethyleneimide, lithium morpholide, 1-lithioazacyclooctane, 6-lithio-1,3,3-trimethyl-6-azabicyclo[3.2.1]octane, and 1-lithio-1,2,3,6-tetrahydropyridine.
  • organomonolithium compounds having a substituted amino group can also be used as solubilized oligomeric organomonolithium compounds by reacting them with a small amount of a polymerizable monomer, such as 1,3-butadiene, isoprene, or styrene.
  • a polymerizable monomer such as 1,3-butadiene, isoprene, or styrene.
  • the polymerization initiator has a nitrogen atom constituting an amino group
  • a chain transfer reaction is likely to occur during the anionic polymerization, and the amount of the coupling modifier reacting with the active terminal after the polymerization is completed tends to be small.
  • the weight-average molecular weight tends to be small.
  • an alkyllithium compound may be used as the organomonolithium compound.
  • an organomonolithium compound is used, a conjugated diene polymer having an alkyl group at the polymerization initiation terminal can be obtained.
  • alkyllithium compounds include, but are not limited to, n-butyllithium, sec-butyllithium, tert-butyllithium, n-hexyllithium, benzyllithium, phenyllithium, and stilbenelithium.
  • alkyllithium compound n-butyllithium and sec-butyllithium are preferred from the viewpoints of industrial availability and ease of control of the polymerization reaction.
  • These organomonolithium compounds may be used alone or in combination of two or more, and may also be used in combination with other organometallic compounds.
  • organometallic compounds include, but are not limited to, alkaline earth metal compounds, alkali metal compounds other than lithium, and other organometallic compounds.
  • alkaline earth metal compounds include, but are not limited to, organomagnesium compounds, organocalcium compounds, and organostrontium compounds, as well as alkaline earth metal alkoxides, sulfonates, carbonates, and amides.
  • organomagnesium compound include, but are not limited to, dibutylmagnesium and ethylbutylmagnesium.
  • organometallic compounds include, but are not limited to, organoaluminum compounds.
  • the amount of polymerization initiator added is preferably determined based on the molecular weight of the desired conjugated diene polymer.
  • the number average molecular weight and/or weight average molecular weight can be controlled by the ratio of the amount of monomer added to the amount of polymerization initiator added. Specifically, decreasing the proportion of the amount of polymerization initiator added tends to increase the molecular weight, while increasing the proportion of the amount of polymerization initiator added tends to decrease the molecular weight.
  • an inert solvent examples include, but are not limited to, hydrocarbon solvents such as saturated hydrocarbons and aromatic hydrocarbons.
  • hydrocarbon solvents include, but are not limited to, 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; and hydrocarbons consisting of mixtures thereof.
  • the polymerization reaction in the polymerization step may be carried out using, for example, the following method, as described in JP-A-59-140211. That is, a method may be used in which the polymerization reaction is first initiated using the entire amount of the vinyl aromatic compound and a portion of the conjugated diene compound, and then the remaining conjugated diene compound is added intermittently during the polymerization reaction.
  • the polymerization temperature in the polymerization reaction in the polymerization step is not particularly limited, but is preferably a temperature at which living anionic polymerization proceeds. Furthermore, from the viewpoint of improving productivity, it is more preferably 0°C or higher, and even more preferably 0°C or higher and 120°C or lower. Having a polymerization temperature in the polymerization reaction within the above range tends to sufficiently enhance reactivity with the coupling modifier in the coupling step described below. From the same viewpoint, the polymerization temperature in the polymerization reaction is even more preferably 50°C or higher and 100°C or lower.
  • a polar compound may be added in the polymerization process. Adding a polar compound tends to produce a conjugated diene polymer in which a vinyl aromatic compound and a conjugated diene compound are copolymerized in a more random fashion. As such, polar compounds have an effective randomizing effect in the copolymerization of a conjugated diene compound and a vinyl aromatic compound, and can therefore be used as an agent for adjusting the distribution of the vinyl aromatic compound and the amount of styrene blocks. Polar compounds can also promote the polymerization reaction and can be used as a vinylating agent for controlling the microstructure of the conjugated diene polymer.
  • polar compounds are used as vinylating agents, randomizing agents, and polymerization accelerators
  • reducing the amount of polar compound to adjust the vinylation rate or randomization rate tends to reduce the polymerization-accelerating effect. Therefore, in a method of adjusting the branching degree of a polymer by reacting a coupling modifier with polymerization end terminals, reducing the amount of polar compound added increases the polymerization time and the proportion of deactivated polymerization end terminals. As a result, such a method tends to make it difficult to increase the modification rate.
  • the production method of this embodiment can increase the branching degree of the polymer using a branching agent, as described below, and therefore allows the branching degree to be controlled independently of the vinylation rate and randomization rate, which is advantageous in terms of structural design of conjugated diene polymers.
  • Polar compounds include, but are not limited to, 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; tertiary amine compounds such as tetramethylethylenediamine, dipiperidinoethane, trimethylamine, triethylamine, pyridine, and quinuclidine; alkali metal alkoxide compounds such as potassium tert-amylate, potassium tert-butylate, sodium tert-butylate, and sodium amylate; and phosphine compounds such as triphenylphosphine. These polar compounds may be used alone or in combination of two or more.
  • ethers such as tetrahydrofuran, diethyl ether
  • the amount of polar compound added is not particularly limited, but can be adjusted depending on the amount of polymerization active terminals, i.e., the amount of polymerization initiator added.
  • the amount of polar compound added is preferably 0.010 mol or more and 1.0 mol or less, and more preferably 0.10 mol or more and 0.70 mol or less, per mol of polymerization initiator. Within the above range, the amount of polar compound added may be 0.60 mol or less or 0.50 mol or less per mol of polymerization initiator. Alternatively, it may be 0.15 mol or more or 0.20 mol or more per mol of polymerization initiator.
  • the amount of polar compound added When the amount of polar compound added is equal to or less than the above upper limit, a conjugated diene polymer with a low Tg tends to be obtained. Furthermore, when the amount of polar compound added is equal to or greater than the above lower limit, deactivation of the polymerization active terminals is suppressed, and the coupling rate in the coupling step described below tends to be improved.
  • the amount of polar compound added may be within a range that combines any of the above upper and lower limits.
  • the methods for producing conjugated diene polymer (A) and conjugated diene polymer (B) may include a step of removing impurities before the polymerization step.
  • impurities when the above-mentioned monomers, polymerization initiator, and/or inert solvent contain allenes and acetylenes as impurities, it is preferable to include a step of removing impurities before the polymerization step. Including a step of removing impurities tends to produce a conjugated diene polymer with a high concentration of active ends, and tends to produce a modified conjugated diene polymer with a high modification rate in the coupling step described below.
  • Examples of such impurity removal steps include, but are not limited to, a step of treating with an organometallic compound.
  • organometallic compounds include, but are not limited to, organolithium compounds, and examples of organolithium compounds include, but are not limited to, n-butyllithium.
  • a branching reaction is initiated in the conjugated diene polymer by adding a branching agent, which will be described later. After the branching agent is added, the polymerization reaction in which the conjugated diene polymer grows and the branching reaction in which the conjugated diene polymer branches occur in competition with each other in the reaction system.
  • the type and amount of branching agent added as well as the timing of adding the branching agent, it is possible to control the weight average molecular weight, number average molecular weight, their ratio (Mw/Mn), and absolute molecular weight of the conjugated diene polymer obtained in the polymerization branching step, as well as the branching degree, number of branching points, and number of branches at the branching points of the conjugated diene polymer.
  • the total amount of active ends of the conjugated diene polymer in the reaction system can be reduced compared to the amount of polymerization initiator added, and even if a small amount of polar compound is added, the initial polymerization reaction can be promoted and the activity of the active polymerization ends can be maintained.
  • the coupling rate and/or modification rate of the polymerization end ends can be easily improved.
  • the amount of polar compound added can be adjusted to control the microstructure, such as the amount of bound vinyl aromatic monomer units and the amount of vinyl bonds.
  • the amount of polar compound typically used to maintain the amount of bound vinyl aromatic monomer units and the amount of vinyl bonds within the above-mentioned ranges is insufficient from the perspective of maintaining the active terminals of the conjugated diene polymer in the reaction system, and it is not easy to sufficiently maintain the activity of the active polymerization terminals, unless a branching agent is added.
  • the active terminals of the polymer can be sufficiently maintained, and a high coupling rate and modification rate can be achieved.
  • the timing of adding the branching agent in the branching step is not particularly limited, and can be appropriately selected depending on the application of the conjugated diene polymer to be produced. From the viewpoint of improving the absolute molecular weight of the resulting conjugated diene polymer and improving the modification rate in the coupling step, the timing for adding the branching agent is preferably when the raw material conversion rate after addition of the polymerization initiator is 20% or higher, more preferably 40% or higher, even more preferably 50% or higher, even more preferably 65% or higher, and even more preferably 75% or higher. In other words, the timing for adding the branching agent is preferably when the polymerization reaction is sufficiently stable. By setting the timing for adding the branching agent within the above range, a conjugated diene polymer with a higher modification rate in the coupling step can be obtained even if a small amount of polar compound is added or no polar compound is added.
  • the branching agent is not particularly limited, but for example, a compound represented by the following formula (10) or formula (11) can be used.
  • R 1 represents a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, or an aryl group having 6 to 20 carbon atoms, and may have a branched structure in part.
  • R 2 and R 3 each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, which may partially have a branched structure. When a plurality of R 2 to R 3 are present, they are independent of each other.
  • X 1 independently represents a halogen atom.
  • m represents an integer of 0 to 2
  • n represents an integer of 0 to 3
  • l represents an integer of 0 to 3.
  • R 4 to R 7 each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms, and may partially have a branched structure. When there are a plurality of R 4 to R 7 , they are independent of each other.
  • X 2 and X 3 each independently represent a halogen atom.
  • m represents an integer of 0 to 2
  • n represents an integer of 0 to 3
  • l represents an integer of 0 to 3.
  • (m+n+l) represents 3.
  • a represents an integer of 0 to 3
  • b represents an integer of 0 to 2
  • c represents an integer of 0 to 3.
  • (a+b+c) represents 3.
  • Branching agents represented by formula (10) include, but are not limited to, trimethoxy(4-vinylphenyl)silane, triethoxy(4-vinylphenyl)silane, tripropoxy(4-vinylphenyl)silane, tributoxy(4-vinylphenyl)silane, triisopropoxy(4-vinylphenyl)silane, trimethoxy(3-vinylphenyl)silane, triethoxy(3-vinylphenyl)silane, tripropoxy(3-vinylphenyl)silane, tributoxy(3-vinylphenyl)silane, triisopropoxy(3-vinylphenyl)silane, trimethoxy(2-vinylphenyl)silane )silane, triethoxy(2-vinylphenyl)silane, tripropoxy(2-vinylphenyl)silane, tribut
  • branching agents represented by the formula (10) include trimethoxy(4-isopropenylphenyl)silane, triethoxy(4-isopropenylphenyl)silane, tripropoxy(4-isopropenylphenyl)silane, tributoxy(4-isopropenylphenyl)silane, triisopropoxy(4-isopropenylphenyl)silane, trimethoxy(3-isopropenylphenyl)silane, triethoxy(3-isopropenylphenyl)silane, Tripropoxy(3-isopropenylphenyl)silane, tributoxy(3-isopropenylphenyl)silane, triisopropoxy(3-isopropenylphenyl)silane, trimethoxy(2-isopropenylphenyl)silane, triethoxy(2-isopropenylpheny
  • Branching agents represented by the formula (11) include, but are not limited to, 1,1-bis(4-trimethoxysilylphenyl)ethylene, 1,1-bis(4-triethoxysilylphenyl)ethylene, 1,1-bis(4-tripropoxysilylphenyl)ethylene, 1,1-bis(4-tripentoxysilylphenyl)ethylene, 1,1-bis(4-triisopropoxysilylphenyl)ethylene, 1,1-bis(3-trimethoxysilylphenyl)ethylene, 1,1-bis(3-triethoxysilylphenyl)ethylene, 1,1-bis(3-trippropoxysilylphenyl)ethylene, 1,1-bis(3-tripentoxysilylphenyl)ethylene, 1,1-bis(3-triisopropoxysilylphenyl)ethylene, 1,1-bis(2 -trimethoxysilylphenyl)ethylene, 1,1-bis(2-triethoxysilylphenyl)ethylene
  • 1,1-bis(4-trimethoxysilylphenyl)ethylene, 1,1-bis(4-triethoxysilylphenyl)ethylene, 1,1-bis(4-tripropoxysilylphenyl)ethylene, 1,1-bis(4-tripentoxysilylphenyl)ethylene, and 1,1-bis(4-triisopropoxysilylphenyl)ethylene are preferred, with 1,1-bis(4-trimethoxysilylphenyl)ethylene being more preferred.
  • the amount of such a branching agent to be added is not particularly limited and can be appropriately selected depending on the intended use of the conjugated diene polymer, but is preferably 0.020 mol or more and 0.50 mol or less, and more preferably 0.025 mol or more and 0.40 mol or less, relative to 1 mol of the polymerization initiator.
  • the amount of the branching agent added may be 0.030 mol or more or 0.035 mol or more per mol of the polymerization initiator, or 0.30 mol or less or 0.25 mol or less per mol of the polymerization initiator, within the above range.
  • the amount of branching agent added may be within a range that is any combination of the above upper and lower limits.
  • the amount of branching agent added affects the degree of branching of the entire conjugated diene-based polymer, and as the amount added increases, the overall degree of branching and the degree of branching at the extreme values increase.
  • the reaction temperature may or may not be changed after the branching agent is added.
  • the monomers that are raw materials for the conjugated diene polymer may be further added, and then the branching agent may be further added, and the addition of the branching agent and monomers may be repeated.
  • the monomer to be added is not particularly limited, but from the viewpoint of improving the modification rate in the coupling step, it is preferable to add the same monomer as that added initially as the monomer in the polymerization branching step.
  • the amount of the added monomer may be 1.0% or more, 5.0% or more, 10% or more, 15% or more, or 20% or more of the total amount of monomers used for the conjugated diene polymer, and may be 50% or less, 40% or less, or 35% or less.
  • the amount of the added monomer is within the above range, the molecular weight between the branching point formed by adding the branching agent and the branching point formed by adding the coupling modifier becomes longer, and therefore the polymer tends to have a highly linear molecular structure.
  • the entanglement of molecular chains of the conjugated diene polymer increases when the polymer is vulcanized, and the vulcanized polymer tends to have excellent abrasion resistance, handling stability, and breaking strength.
  • the conjugated diene polymer having a branched structure obtained by the polymerization-branching step described above may be reacted with a coupling modifier to form a modified conjugated diene polymer.
  • the conjugated diene polymer having a branched structure obtained by the polymerization-branching step can be modified with a nitrogen-containing functional group having affinity or binding reactivity with a filler.
  • multiple conjugated diene polymers can be coupled together.
  • the coupling modifier is not particularly limited as long as it has a nitrogen atom-containing functional group that has affinity or bonding reactivity with the filler and is a reactive compound having two or more functional groups that can react with the active terminal of the conjugated diene polymer.
  • Such coupling modifiers include, for example, coupling modifiers containing a nitrogen atom and further having a group containing a nitrogen atom and a silicon atom.
  • Coupling modifiers having a nitrogen atom-containing group include, but are not limited to, isocyanate compounds, isothiocyanate compounds, isocyanuric acid derivatives, nitrogen atom-containing carbonyl compounds, nitrogen atom-containing vinyl compounds, nitrogen atom-containing epoxy compounds, imine compounds, and nitrogen atom-containing alkoxysilane compounds.
  • amine compounds without active hydrogen include tertiary amine compounds.
  • Isocyanate compounds include, but are not limited to, 2,4-tolylene diisocyanate, 2,6-tolylene diisocyanate, diphenylmethane diisocyanate, polymeric diphenylmethane diisocyanate (C-MDI), phenyl isocyanate, isophorone diisocyanate, hexamethylene diisocyanate, butyl isocyanate, and 1,3,5-benzene triisocyanate.
  • isothiocyanate compounds include, but are not limited to, 2,4-tolylene diisothiocyanate, 2,6-tolylene diisothiocyanate, diphenylmethane diisothiocyanate, phenyl isothiocyanate, isophorone diisothiocyanate, hexamethylene diisothiocyanate, butyl isothiocyanate, and 1,3,5-benzenetriisothiocyanate.
  • Isocyanuric acid derivatives include, but are not limited to, 1,3,5-tris(3-trimethoxysilylpropyl)isocyanurate, 1,3,5-tris(3-triethoxysilylpropyl)isocyanurate, 1,3,5-tri(oxiran-2-yl)-1,3,5-triazinane-2,4,6-trione, 1,3,5-tris(isocyanatomethyl)-1,3,5-triazinane-2,4,6-trione, and 1,3,5-trivinyl-1,3,5-triazinane-2,4,6-trione.
  • Nitrogen atom-containing carbonyl compounds include, but are not limited to, 1,3-dimethyl-2-imidazolidinone, 1-methyl-3-ethyl-2-imidazolidinone, 1-methyl-3-(2-methoxyethyl)-2-imidazolidinone, N-methyl-2-pyrrolidone, N-methyl-2-piperidone, N-methyl-2-quinolone, 4,4'-bis(diethylamino)benzophenone, 4,4'-bis(dimethylamino)benzophenone, methyl-2-pyrrolidone, Examples include diethyl ketone, methyl-4-pyridyl ketone, propyl-2-pyridyl ketone, di-4-pyridyl ketone, 2-benzoylpyridine, N,N,N',N'-tetramethylurea, N,N-dimethyl-N',N'-diphenylurea, N,N-methyl diethylcarba
  • nitrogen-containing vinyl compounds include, but are not limited to, N,N-dimethylacrylamide, N,N-dimethylmethacrylamide, N-methylmaleimide, N-methylphthalimide, N,N-bistrimethylsilylacrylamide, morpholinoacrylamide, 3-(2-dimethylaminoethyl)styrene, (dimethylamino)dimethyl-4-vinylphenylsilane, 4,4'-vinylidenebis(N,N-dimethylaniline), 4,4'-vinylidenebis(N,N-diethylaniline), 1,1-bis(4-morpholinophenyl)ethylene, and 1-phenyl-1-(4-N,N-dimethylaminophenyl)ethylene.
  • nitrogen-containing epoxy compounds include, but are not limited to, hydrocarbon compounds containing an epoxy group bonded to an amino group.
  • the hydrocarbon compound containing an epoxy group bonded to an amino group may further contain an epoxy group bonded to an ether group.
  • nitrogen-containing epoxy compounds include, but are not limited to, compounds represented by the following formula (12):
  • R is a divalent or higher organic group containing at least one polar group selected from a divalent or higher hydrocarbon group, or an oxygen-containing polar group such as an ether, epoxy, or ketone, a sulfur-containing polar group such as a thioether or thioketone, or a nitrogen-containing polar group such as a tertiary amino group or imino group.
  • the divalent or higher hydrocarbon group may be saturated or unsaturated, linear, branched, or cyclic, and includes alkylene groups, alkenylene groups, phenylene groups, etc. Preferably, it is a hydrocarbon group having 1 to 20 carbon atoms. Examples include methylene, ethylene, butylene, cyclohexylene, 1,3-bis(methylene)-cyclohexane, 1,3-bis(ethylene)-cyclohexane, o-, m-, and p-phenylene, m-, and p-xylene, and bis(phenylene)-methane.
  • R 24 and R 27 are hydrocarbon groups having 1 to 10 carbon atoms, and R 24 and R 27 may be the same or different.
  • R 25 and R 28 are hydrogen or a hydrocarbon group having 1 to 10 carbon atoms, and R 25 and R 28 may be the same or different.
  • R 26 is a hydrocarbon group having 1 to 10 carbon atoms or a structure of the following formula (13).
  • R 24 , R 25 and R 26 may be bonded to each other to form a cyclic structure.
  • R 26 when R 26 is a hydrocarbon group, it may be a cyclic structure bonded to R. In the case of the cyclic structure, the N bonded to R 26 and R may be directly bonded to each other.
  • f is an integer of 1 or more
  • g is 0 or an integer of 1 or more.
  • R 29 and R 30 are defined in the same manner as R 24 and R 25 in the formula (12), and R 29 and R 30 may be the same or different.
  • the above-mentioned nitrogen-containing epoxy compound is preferably a nitrogen-containing epoxy compound having one or more diglycidylamino groups and one or more glycidoxy groups in the molecule.
  • nitrogen atom-containing epoxy compounds include, but are not limited to, N,N-diglycidyl-4-glycidoxyaniline, 1-N,N-diglycidylaminomethyl-4-glycidoxycyclohexane, 4-(4-glycidoxyphenyl)-(N,N-diglycidyl)aniline, 4-(4-glycidoxyphenoxy)-(N,N-diglycidyl)aniline, 4-(4-glycidoxybenzyl)-(N,N-diglycidyl)aniline, 4-(N,N'-diglycidyl-2-piperazinyl)-glycidoxybenzene, 1,3-bis(N,N-diglycidylaminomethyl)cyclohexane, and N,N,N',N'-tetraglycidyl-m-xylylenediamine.
  • Imine compounds that are coupling modifiers having a group containing a nitrogen atom include, but are not limited to, N-butylpropan-2-imine, N-butyl-4-methylpentan-2-imine, N,N'-(propane 1,3-diyl)bis(4-methylpentan-2-imine), N,N'-(hexane 1,6-diyl)bis(4-methylpentan-2-imine), tris[2-(propan-2-ylideneamino) )ethyl]amine, tris[2-(propan-2-ylideneamino)propyl]amine, N,N'-(1,4-phenylene)bis(4-methylpentan-2-imine), 1,1'-(1,4-phenylene)bis(N-propylethane-1-imine), N,N'-(propane-1,3-diyl)bis(1-phenylmethanimine), and N,N'-
  • Nitrogen-containing alkoxysilane compounds which are coupling modifiers having a group containing a nitrogen atom, include, but are not limited to, 3-dimethylaminopropyltrimethoxysilane, 3-dimethylaminopropylmethyldimethoxysilane, 3-diethylaminopropyltriethoxysilane, 3-morpholinopropyltrimethoxysilane, 3-piperidinopropyltriethoxysilane, 3-hexamethyleneiminopropylmethyldiethoxysilane, 3-(4-methyl-1-piperazino)propyltriethoxysilane, 3-(4-methyl-1-piperazino)propyltrimethoxysilane, 1-[3-(triethoxysilyl)propyl]-3-methylhexahydropyrimidine, 3-(4-trimethylsilyl-1-piperazino)propyltriethoxysilane, 3-(3-triethyls
  • Preferred nitrogen atom-containing alkoxysilane compounds include, but are not limited to, tris(3-trimethoxysilylpropyl)amine, tris(3-triethoxysilylpropyl)amine, tris(3-tripropoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine ("N,N,N',N'-tetrakis(3-tri) bis(3-trimethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsily
  • protected amine compounds in which active hydrogen is replaced with a protecting group include compounds having an unsaturated bond and a protected amine in the molecule.
  • examples of such compounds include, but are not limited to, 4,4'-vinylidenebis[N,N-bis(trimethylsilyl)aniline], 4,4'-vinylidenebis[N,N-bis(triethylsilyl)aniline], 4,4'-vinylidenebis[N,N-bis(t-butyldimethylsilyl)aniline], 4,4'-vinylidenebis[N-methyl-N-(trimethylsilyl)aniline], 4,4'-vinylidenebis[N-ethyl-N-(trimethylsilyl)aniline], 4,4'-vinylidenebis[N-methyl-N-(triethylsilyl)aniline], Examples include 4,4'-vinylidenebis[N-ethyl
  • examples of protected amine compounds in which active hydrogen is substituted with a protecting group include compounds having alkoxysilanes and protected amines in the molecule.
  • examples of such compounds include, but are not limited to, N,N-bis(trimethylsilyl)aminopropyltrimethoxysilane, N,N-bis(trimethylsilyl)aminopropylmethyldimethoxysilane, N,N-bis(trimethylsilyl)aminopropyltriethoxysilane, N,N-bis(trimethylsilyl)aminopropylmethyldiethoxysilane, N,N-bis(trimethylsilyl)aminoethyltrimethoxysilane, N,N-bis(trimethylsilyl)aminoethylmethyldiethoxysilane, N,N-bis(triethylsilyl)aminopropyltrimethoxysilane
  • two or more types of nitrogen-containing alkoxysilane compounds represented by any one of the following formulas (14) to (18) may be used in combination as coupling modifiers.
  • a coupling modifier having two or less alkoxysilyl groups and a coupling modifier having more than two alkoxysilyl groups can be used in combination.
  • R 8 to R 10 are hydrocarbon groups having 1 to 20 carbon atoms, which may contain an unsaturated bond, and may be the same or different.
  • R 11 and R 12 are aliphatic hydrocarbon groups having 1 to 6 carbon atoms, which may contain an unsaturated bond, and may be the same or different.
  • R 13 is a hydrocarbon group having 1 to 20 carbon atoms which contains Si, O, or N and may be substituted with an organic group having no active hydrogen, and which may contain an unsaturated bond.
  • d is an integer of 1 to 3.
  • R 14 to R 16 are hydrocarbon groups having 1 to 20 carbon atoms, which may contain unsaturated bonds, and may be the same or different.
  • R 17 and R 18 are hydrocarbon groups containing Si, O, or N and having 1 to 20 carbon atoms, which may be substituted with an organic group having no active hydrogen, and which may have an unsaturated bond.
  • e is an integer of 1 to 3.
  • R 31 to R 34 each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms
  • R 35 represents an alkylene group having 1 to 10 carbon atoms
  • R 36 represents an alkylene group having 1 to 20 carbon atoms.
  • h represents an integer of 1 to 3
  • i represents an integer of 1 or 2
  • (h+i) represents an integer of 4 or greater.
  • R 37 to R 42 each independently represent an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms
  • R 43 to R 45 each independently represent an alkylene group having 1 to 20 carbon atoms.
  • m, n, and l each independently represent an integer of 1 to 3, and (m+n+l) represents an integer of 4 or greater.
  • R 46 to R 48 each independently represent a single bond or an alkylene group having 1 to 20 carbon atoms
  • R 49 to R 52 each independently represent an alkyl group having 1 to 20 carbon atoms
  • R 53 and R 56 each independently represent an alkylene group having 1 to 20 carbon atoms
  • R 54 represents an alkylene group or an alkoxy group having 1 to 20 carbon atoms
  • R 55 represents an alkyl group or a trialkylsilyl group having 1 to 20 carbon atoms.
  • o represents an integer of 1 to 3
  • p represents 1 or 2;
  • A represents a hydrocarbon group having 1 to 20 carbon atoms or an organic group having at least one atom selected from the group consisting of oxygen atoms, nitrogen atoms, silicon atoms, sulfur atoms, and phosphorus atoms and having no active hydrogen atoms.
  • Coupling modifiers represented by formula (14) include, but are not limited to, 1-methyl-4-(3-(trimethoxysilyl)propyl)piperazine, 1-methyl-4-(3-(triethoxysilyl)propyl)piperazine, 1-ethyl-4-(3-(trimethoxysilyl)propyl)piperazine, 1-ethyl-4-(3-(triethoxysilyl)propyl)piperazine, 1-propyl-4-(3-(trimethoxysilyl)propyl)piperazine, 1-propyl-4-(3-(triethoxysilyl)propyl)piperazine, 1-butyl-4-(3-(trimethoxysilyl)propyl)piperazine, 1-butyl-4-(3-(triethoxysilyl)propyl)piperazine, 1-trimethylsilyl 1-4-(3-(trimethoxysilyl)propyl)piperazine, 1-
  • d in formula (14) is 3 are preferred.
  • 1-methyl-4-(3-(trimethoxysilyl)propyl)piperazine and 1-methyl-4-(3-(triethoxysilyl)propyl)piperazine are preferred.
  • reaction temperature, reaction time, etc. are not particularly limited, but it is preferable to react at a temperature of 0°C or higher and 120°C or lower for 30 seconds or longer.
  • the amount of coupling modifier represented by formula (14) added is preferably in a range such that the total number of moles of alkoxy groups (OR 8 ) bonded to silyl groups in the compound represented by formula (14) is 0.2 to 2.5 times the number of moles of polymerization initiator added, more preferably 0.5 to 2.0 times, and even more preferably 1.0 to 2.0 times. From the viewpoint of achieving a more preferable range for the modification rate and molecular weight of the resulting conjugated diene polymer, the amount is preferably 0.2 times or more. Furthermore, from the viewpoint of preventing a decrease in processability due to an excessive increase in branching degree, the amount is preferably 2.5 times or less.
  • the amounts of the polymerization initiator and the coupling modifier represented by formula (14) added can be adjusted so that the number of moles of the polymerization initiator is preferably 1.5 times or more, and more preferably 1.7 times or more, the number of moles of the coupling modifier represented by formula (14).
  • Coupling modifiers represented by formula (15) include, but are not limited to, N-(1,3-dimethylbutylidene)-3-(triethoxysilyl)-1-propanamine, N-(1,3-dimethylbutylidene)-3-(trimethoxysilyl)-1-propanamine, N-(1,3-dimethylbutylidene)-3-methyl(dimethoxysilyl)-1-propanamine, N-(1,3-dimethylbutylidene)-3-methyl(dimethoxysilyl)-1-propanamine, N-(1-methylethylidene)-3-methyl(diethoxysilyl)-1-propanamine, N-(1-methylethylidene)-3-(triethoxysilyl)-1-propanamine, N-(1-methylethylidene)-3-(trimethoxysilyl)-1-propanamine, N-(1-methylethylidene)-3-methyl
  • reaction temperature, reaction time, etc. are not particularly limited, but it is preferable to react at a temperature of 0°C or higher and 120°C or lower for 30 seconds or longer.
  • the amount of coupling modifier represented by formula (15) added is preferably in a range such that the total number of moles of alkoxy groups (OR 14 ) bonded to silyl groups in the compound represented by formula (15) is 0.2 to 2.5 times the number of moles of polymerization initiator added, more preferably 0.5 to 2.0 times, and even more preferably 1.0 to 2.0 times. From the viewpoint of achieving a more preferable range for the modification rate and molecular weight of the resulting conjugated diene polymer, the amount is preferably 0.2 times or more. Furthermore, from the viewpoint of preventing a decrease in processability due to an excessive increase in branching degree, the amount is preferably 2.5 times or less.
  • the amounts of the polymerization initiator and the coupling modifier represented by formula (15) added can be adjusted so that the number of moles of the polymerization initiator is preferably 1.5 times or more, and more preferably 1.7 times or more, the number of moles of the coupling modifier represented by formula (15).
  • Coupling modifiers having a nitrogen atom-containing group represented by formula (16) include, but are not limited to, 2,2-dimethoxy-1-(3-trimethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-diethoxy-1-(3-triethoxysilylpropyl)-1-aza-2-silacyclopentane, 2,2-dimethoxy-1-(4-trimethoxysilylbutyl)-1-aza-2-silacyclohexane, 2,2-dimethoxy-1-(5-trimethoxysilylpentyl)-1-aza-2-silacycloheptane, 2,2-dimethoxy-1-(3-dimethoxymethylsilylpropyl)-1-aza-2-silacyclohexane, Examples include aza-2-silacyclopentane, 2,2-diethoxy-1-(3-diethoxyethylsilylpropyl)-1-aza-2
  • the reaction temperature and reaction time are not particularly limited, but the reaction is preferably carried out at a temperature of 0°C or higher and 120°C or lower, and for 30 seconds or longer.
  • the amount of coupling modifier represented by formula (16) added is preferably in a range such that the total number of moles of alkoxy groups bonded to silyl groups in the compound represented by formula (16) is 0.2 to 2.5 times the number of moles of polymerization initiator added, more preferably 0.5 to 2.0 times, and even more preferably 1.0 to 2.0 times. From the viewpoint of achieving even more preferred ranges for the modification rate, molecular weight, and branched structure of the resulting conjugated diene polymer, an amount of 0.2 times or more is preferred. Furthermore, from the viewpoint of preventing a decrease in processability due to an excessive increase in branching degree, an amount of 2.5 times or less is preferred.
  • the amounts of the polymerization initiator and the coupling modifier represented by formula (16) added may be adjusted so that the number of moles of the polymerization initiator is preferably 3.0 times or more, and more preferably 4.0 times or more, the number of moles of the coupling modifier represented by formula (16).
  • modifying agents having a nitrogen atom-containing group represented by formula (17) include, but are not limited to, tris(3-trimethoxysilylpropyl)amine, tris(3-methyldimethoxysilylpropyl)amine, tris(3-triethoxysilylpropyl)amine, tris(3-methyldiethoxysilylpropyl)amine, tris(trimethoxysilylmethyl)amine, tris(2-trimethoxysilylethyl)amine, and tris(4-trimethoxysilylbutyl)amine.
  • n, m, and l all represent 3 in formula (17).
  • Preferred examples include tris(3-trimethoxysilylpropyl)amine and tris(3-triethoxysilylpropyl)amine.
  • reaction temperature, reaction time, etc. are not particularly limited, but it is preferable to react at a temperature of 0°C or higher and 120°C or lower for 30 seconds or longer.
  • the total number of moles of alkoxy groups bonded to silyl groups in the coupling modifier represented by formula (17) is preferably in the range of 0.2 to 2.0 times the number of moles of lithium constituting the polymerization initiator described above, more preferably in the range of 0.5 to 2.0 times, and even more preferably in the range of 0.6 to 1.6 times. From the viewpoint of obtaining a sufficient modification rate, molecular weight, and branched structure in the conjugated diene polymer, a value of 0.2 times or more is preferred. A value of 2.0 times or less is preferred because it is preferable to couple polymer ends together to obtain a branched polymer component for improved processability, and from the viewpoint of the cost of the coupling modifier.
  • the number of moles of the polymerization initiator is preferably 4.0 times or more, and more preferably 5.0 times or more, relative to the number of moles of the modifying agent.
  • A is preferably represented by any of the following general formulas (i) to (iv):
  • B 1 represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and t represents an integer of 1 to 10. When a plurality of B 1s are present, they are each independent.
  • B2 represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms
  • B3 represents an alkyl group having 1 to 20 carbon atoms
  • t represents an integer of 1 to 10.
  • B 4 represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and t represents an integer of 1 to 10. When a plurality of B 4s are present, they are each independent.
  • B5 represents a single bond or a hydrocarbon group having 1 to 20 carbon atoms, and t represents an integer of 1 to 10. When a plurality of B5s are present, they are independent of each other.
  • examples of coupling modifiers having a nitrogen atom-containing group include, but are not limited to, tris(3-trimethoxysilylpropyl)amine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)amine, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, tris(3-ethoxysilylpropyl)amine, bis(3-triethoxysilylpropyl)-[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]amine, bis[3-(2,2 -diethoxy-1
  • tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine tris(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-[3-(1 -methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)propyl]-1,3-propanediamine, bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)-[3-(1-methoxy-2-trimethylsilylpropy
  • examples of coupling modifiers having a nitrogen atom-containing group include, but are not limited to, tris(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, bis(2-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-methyl-1,3-propanediamine, bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)-methyl-1,3-propanediamine, tris(3-triethoxysilylpropyl)-methyl-1,3-propanediamine, bis(2-triethoxysilylpropyl)-[3-(2, Examples include bis[3-(2,2-diethoxy-1-aza-2-silacyclopentane)propyl]-methyl-1,3-propanediamine, bis(2-triethoxy
  • examples of coupling modifiers having a group containing a nitrogen atom include, but are not limited to, tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, tris[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-(3-trimethoxysilylpropyl)silane, tris[3-(2,2-dimethoxy-1-aza-2- silane, bis(3-trimethoxysilylpropyl)-bis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]silane, (3-trimethoxysilyl)-[3-(1-methoxy-2-trimethylsilyl-1-sila-2-azacyclopentane)bis[3-(2,2-dimethoxy-1-aza-2-
  • examples of modifiers having a nitrogen atom-containing group include, but are not limited to, 3-tris[2-(2,2-dimethoxy-1-aza-2-silacyclopentane)ethoxy]silyl-1-(2,2-dimethoxy-1-aza-2-silacyclopentane)propane and 3-tris[2-(2,2-dimethoxy-1-aza-2-silacyclopentane)ethoxy]silyl-1-trimethoxysilylpropane.
  • A is preferably represented by formula (i) or formula (ii), and s is 0.
  • Coupling modifiers having such a nitrogen atom-containing group tend to be easily available and tend to provide superior abrasion resistance and low hysteresis loss when the conjugated diene polymer is vulcanized.
  • Examples of coupling modifiers having such a nitrogen atom-containing group include, but are not limited to, bis(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]amine, tris(3-trimethoxysilylpropyl)amine, tris(3-triethoxysilylpropyl)amine, tris(3-trimethoxysilylpropyl)-[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tetrakis[3-(2,2-di Examples include bis[3-(2,2-dimethoxy-1-aza-2-silacyclopen
  • A is more preferably represented by formula (i) or formula (ii), s represents 0, and in formula (i) or formula (ii), t represents an integer from 2 to 10.
  • Examples of coupling modifiers having such a nitrogen atom-containing group include, but are not limited to, tetrakis[3-(2,2-dimethoxy-1-aza-2-silacyclopentane)propyl]-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine, tetrakis(3-trimethoxysilylpropyl)-1,3-bisaminomethylcyclohexane, and N 1 -(3-(bis(3-(trimethoxysilyl)propyl)amino)propyl)-N 1 -methyl-N 3 -(3-(methyl(3-(trimethoxysilyl)propyl)amino)propyl)-N 3 -(3-(trimethoxysilyl)propyl)-1,3-propanediamine.
  • the amount of the compound represented by formula (18) added as a coupling modifier having a nitrogen atom-containing group can be adjusted so that the number of moles of polymerization initiator and the number of moles of coupling modifier react in the desired stoichiometric ratio, which tends to achieve the desired star-shaped highly branched structure.
  • the number of moles of the polymerization initiator is preferably 5.0 times or more, and more preferably 6.0 times or more, the number of moles of the coupling modifier.
  • the number of functional groups of the coupling modifier ((o-1) x q + p x r + s) is preferably an integer from 5 to 10, and more preferably an integer from 6 to 10.
  • the method for producing the conjugated diene polymer (A) and the conjugated diene polymer (B) may include a condensation reaction step in which a condensation promoter is added to cause a condensation reaction after the step of adding the coupling modifier and/or before the step of adding the coupling modifier.
  • the method for producing the conjugated diene polymer (A) and the conjugated diene polymer (B) may further include a modification step using a modifier other than the coupling modifier described above.
  • two types of coupling modifiers may be added, or three or more types of coupling modifiers may be added, in the step of adding the coupling modifier.
  • two types of coupling modifiers it is preferable to use a combination of coupling modifiers having different numbers of functional groups.
  • three or more types of coupling modifiers it is preferable to use a combination of coupling modifiers having different numbers of functional groups.
  • the method for producing a conjugated diene polymer of this embodiment may include a hydrogenation step in which the conjugated diene portion is hydrogenated.
  • the method for hydrogenating the conjugated diene portion is not particularly limited, and known methods can be used.
  • a preferred hydrogenation step is a method in which gaseous hydrogen is blown into a polymer solution in the presence of a catalyst to hydrogenate the conjugated diene moiety.
  • the catalyst to be used is not particularly limited, but examples thereof include heterogeneous catalysts such as catalysts in which a noble metal is supported on a porous inorganic material; and homogeneous catalysts such as catalysts in which a salt of nickel, cobalt, or the like is solubilized and reacted with organoaluminum, and catalysts using metallocenes such as titanocene.
  • titanocene catalysts are preferred from the viewpoint of allowing selection of milder hydrogenation conditions.
  • a method for hydrogenating aromatic groups a method using a supported noble metal catalyst can be mentioned.
  • a hydrogenation process that does not use gaseous hydrogen is a method in which a polymer solution is contacted with a hydrogenation catalyst.
  • hydrogenation catalysts include, but are not limited to, (1) supported heterogeneous hydrogenation catalysts in which a metal such as Ni, Pt, Pd, or Ru is supported on carbon, silica, alumina, or diatomaceous earth; (2) so-called Ziegler-type hydrogenation catalysts that use a transition metal salt such as an organic acid salt or acetylacetonate salt of Ni, Co, Fe, or Cr, etc., and a reducing agent such as organoaluminum; and (3) so-called organometallic complexes, such as organometallic compounds of Ti, Ru, Rh, or Zr, etc.
  • hydrogenation catalysts include, but are not limited to, known hydrogenation catalysts described in, for example, JP-B Nos. 42-8704, 43-6636, 63-4841, 1988-37970, 1990-53851, 2000-9041, and JP-A No. 8-109219.
  • a preferred hydrogenation catalyst is a reaction mixture of a titanocene compound and a reducing organometallic compound.
  • a stabilizer such as a deactivator and/or a neutralizer may be added to the polymer solution as needed.
  • Quenching agents include, but are not limited to, water and alcohols such as methanol, ethanol, and isopropanol.
  • Neutralizing agents include, but are not limited to, carboxylic acids such as stearic acid, oleic acid, and versatic acid (a mixture of highly branched carboxylic acids having 9 to 11 carbon atoms, with 10 carbon atoms being the main component), aqueous solutions of inorganic acids, and carbon dioxide gas.
  • carboxylic acids such as stearic acid, oleic acid, and versatic acid (a mixture of highly branched carboxylic acids having 9 to 11 carbon atoms, with 10 carbon atoms being the main component), aqueous solutions of inorganic acids, and carbon dioxide gas.
  • a rubber stabilizer from the viewpoint of preventing gel formation after polymerization and improving stability during processing.
  • Known rubber stabilizers can be used, and examples thereof include, but are not limited to, antioxidants such as 2,6-di-tert-butyl-4-hydroxytoluene (BHT), n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenol)propionate, and 2-methyl-4,6-bis[(octylthio)methyl]phenol.
  • antioxidants such as 2,6-di-tert-butyl-4-hydroxytoluene (BHT), n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenol)propionate, and 2-methyl-4,6-bis[(octylthio)methyl]phenol.
  • a polymerization step and, if necessary, a modification step are carried out to obtain polymerization solutions of the conjugated diene polymer (A) and the conjugated diene polymer (B), and then these are mixed together and the solvent is removed to obtain a conjugated diene polymer.
  • the mixing step it is preferable to provide storage tanks downstream of the reaction tank for the conjugated diene polymer (A) and the reaction tank for the conjugated diene polymer (B) for storing the polymerization solution distilled from each reaction tank.
  • the volume of the storage tank is larger than that of the reaction tank.
  • Mixing means include, but are not limited to, the use of a tank equipped with a rotary agitator, or a pipe equipped with a rotary agitator or static mixer. From the standpoint of mixing capacity, it is preferable to use a tank equipped with a rotary agitator, and from the standpoint of production efficiency, it is preferable to use a pipe equipped with a rotary agitator or static mixer.
  • the temperature during the mixing step is not particularly limited, but is preferably between 0°C and 120°C, and more preferably between 50°C and 100°C. This is because a higher temperature reduces the viscosity of the polymerization solution, making it easier to mix.
  • the solution distilled from the top of the polymerization reactor is temporarily stored and then mixed. If the storage time is short and the temperature of the solution is maintained even after distillation from the polymerization reactor, there is no need to heat the mixing step. However, if the storage time is long or the ambient temperature is low, or if conditions are such that the solution temperature is likely to drop, the storage tank, mixing tank, piping, etc. may be kept warm or heated.
  • the mixing mass ratio of the conjugated diene polymer (A) to the conjugated diene polymer (B) in the mixing step ((A)/(B)) is preferably 10/90 to 40/60, more preferably 15/85 to 35/65, and even more preferably 20/80 to 30/70.
  • the amount is within this range, the bale moldability is good, the processability when vulcanized is excellent, and the abrasion resistance when vulcanized tends to be excellent.
  • the above ratio is the mass ratio of the conjugated diene polymers, and when the concentrations of the polymer solution of the conjugated diene polymer (A) and the polymer solution of the conjugated diene polymer (B) are the same, this may be used as the mass ratio of the solutions as is. However, there are cases where these solution concentrations are different. This is because, when producing a polymer with a low molecular weight, increasing the amount of polymerization initiator added tends to increase the heat of reaction, and therefore the concentration of the solution may be reduced to maintain the polymerization temperature. In this case, it is preferable to adjust the mixing ratio so as to obtain a preferred mass ratio of the polymers, taking into account the solution concentration.
  • the solvent removal step can use known methods such as drying and devolatilization. Examples of such methods include separating the solvent by steam stripping or the like, filtering the polymer, and then dehydrating and drying it to obtain the polymer; concentrating the polymer in a flashing tank and then devolatilizing it using a vent extruder or the like; and directly devolatilizing it using a drum dryer or the like.
  • the rubber composition of the present embodiment contains a rubber component containing the conjugated diene polymer of the present embodiment described above.
  • the conjugated diene polymer of the present embodiment is compounded in a tire, the oil contained in the bale molded article will inevitably be contained in the tire. However, if the amount of oil extension is reduced, the oil contained in the tire will also be reduced, which has the advantage of increasing the degree of freedom in the composition in tire design.
  • the conjugated diene polymer and its sheet- or block-shaped molded product (also referred to as a bale) of this embodiment may contain a softener component, which will be described later.
  • the molded product (bale) preferably contains 2 parts by mass or less of the rubber softener per 100 parts by mass of the conjugated diene polymer, more preferably 1.5 parts by mass or less, even more preferably 1 part by mass or less, even more preferably less than 1 part by mass, and most preferably no softener is added, but the amount of the rubber softener may be more than 2 parts by mass.
  • Rubber softeners are not particularly limited, but examples include extender oils, liquid rubbers, and resins.
  • the conjugated diene polymer and its sheet-like or block-like molded product are provided without adding a rubber softener, from the viewpoint of improving the degree of freedom in compounding design when producing a rubber composition using the molded product.
  • a rubber softener is added to a sheet- or block-shaped molded body of a conjugated diene polymer
  • the rubber composition produced by compounding the molded body also contains the rubber material softener, which puts a strain on the total amount of rubber softeners in the entire rubber composition and limits the degree of freedom in the type and amount of rubber softener that needs to be compounded when producing the rubber composition.
  • extender oil added to the conjugated diene polymer of this embodiment and its sheet- or block-shaped molded product, it becomes possible to compound more resins such as extender oil when producing a rubber composition using these. This is preferable from the perspective of further improving the breaking strength of the rubber composition and its vulcanizate.
  • the rubber composition using the conjugated diene polymer of this embodiment and its sheet- or block-shaped molded article may further contain a rubber stabilizer from the standpoint of suppressing gel formation and improving stability during processing.
  • Rubber stabilizers are not limited to the following and any known stabilizers can be used, but examples include antioxidants such as 2,6-di-tert-butyl-4-hydroxytoluene (hereinafter also referred to as "BHT"), n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenol) propionate, and 2-methyl-4,6-bis[(octylthio)methyl]phenol.
  • antioxidants such as 2,6-di-tert-butyl-4-hydroxytoluene (hereinafter also referred to as "BHT"), n-octadecyl-3-(4'-hydroxy-3',5'-di-tert-butylphenol) propionate, and 2-methyl-4,6-bis[(octylthio)methyl]phenol.
  • the rubber composition of this embodiment contains 100 parts by mass of a rubber component containing the conjugated diene-based polymer of this embodiment, and 20 parts by mass or more and 150 parts by mass or less of a filler.
  • the rubber component preferably contains 10 parts by mass or more of the conjugated diene polymer of the present embodiment relative to 100 parts by mass of the total amount of the rubber component.
  • Fillers include, but are not limited to, silica-based inorganic fillers, carbon black, metal oxides, and metal hydroxides. Among these, silica-based inorganic fillers are preferred. In particular, when the rubber composition of this embodiment is used for vulcanized rubber applications such as tires, automobile parts such as anti-vibration rubber, and shoes, it is particularly preferred that the rubber composition contain a silica-based inorganic filler. Such fillers may be used alone or in combination of two or more types.
  • the silica-based inorganic filler is not particularly limited and known fillers can be used, but solid particles containing SiO2 or Si3Al as a structural unit are preferred, and solid particles containing SiO2 or Si3Al as a main component of the structural unit are more preferred.
  • the main component refers to a component contained in the silica-based inorganic filler in an amount of more than 50 mass%, preferably 70 mass% or more, and more preferably 80 mass% or more.
  • silica-based inorganic fillers include, but are not limited to, inorganic fibrous materials such as silica, clay, talc, mica, diatomaceous earth, wollastonite, montmorillonite, zeolite, and glass fiber.
  • Silica-based inorganic fillers with hydrophobic surfaces and mixtures of silica-based inorganic fillers with non-silica-based inorganic fillers may also be used.
  • silica or glass fiber is preferred, with silica being more preferred, from the viewpoint of further improving the strength and abrasion resistance of the rubber composition.
  • Examples of silica include, but are not limited to, dry silica, wet silica, and synthetic silicate silica. Of these silicas, wet silica is preferred, from the viewpoint of further improving the breaking strength of the rubber composition.
  • the nitrogen adsorption specific surface area of the silica-based inorganic filler determined by the BET adsorption method is preferably 100 m 2 /g or more and 300 m 2 /g or less, and more preferably 170 m 2 /g or more and 250 m 2 /g or less.
  • a silica-based inorganic filler having a relatively small specific surface area e.g., a specific surface area of less than 200 m 2 /g
  • a silica-based inorganic filler having a relatively large specific surface area e.g., 200 m 2 /g or more.
  • the conjugated diene polymer further improves the dispersibility of the silica.
  • the obtained rubber composition tends to have even better abrasion resistance, fracture strength, and low hysteresis loss.
  • carbon black examples include, but are not limited to, carbon blacks of various classes such as SRF, FEF, HAF, ISAF, and SAF. Among these, carbon blacks having a nitrogen adsorption specific surface area of 50 m 2 /g or more as determined by the BET adsorption method and a dibutyl phthalate (DBP) oil absorption of 80 mL/100 g or less are preferred.
  • SRF sulfur adsorption specific surface area
  • DBP dibutyl phthalate
  • the metal oxide is not particularly limited as long as it is a solid particle whose main component is a structural unit of the chemical formula M x O y (M represents a metal atom, and x and y each independently represent an integer of 1 to 6), and examples thereof include alumina, titanium oxide, magnesium oxide, and zinc oxide.
  • Metal hydroxides include, but are not limited to, aluminum hydroxide, magnesium hydroxide, and zirconium hydroxide.
  • the content of the silica-based inorganic filler in the rubber composition of this embodiment is 20 to 150 parts by mass, preferably 30 to 130 parts by mass, and more preferably 40 to 110 parts by mass, per 100 parts by mass of the rubber component.
  • the silica-based inorganic filler is within the above range, the rubber composition tends to have even better processability during vulcanization, and the vulcanizate tends to have even better low hysteresis loss, fracture properties, and abrasion resistance.
  • the rubber composition of this embodiment preferably contains 0.5 parts by mass or more and 100 parts by mass or less of carbon black per 100 parts by mass of the rubber component containing the conjugated diene polymer.
  • the rubber composition preferably contains 3.0 parts by mass or more and 100 parts by mass or less of carbon black, and even more preferably 5.0 parts by mass or more and 50 parts by mass or less, per 100 parts by mass of the rubber component containing the conjugated diene polymer.
  • the rubber composition of the present embodiment may further contain a silane coupling agent.
  • a silane coupling agent is preferably, but not limited to, a compound having a sulfur bond moiety and an alkoxysilyl group or a silanol group moiety in one molecule, such as, but not limited to, bis-[3-(triethoxysilyl)-propyl]-tetrasulfide, bis-[3-(triethoxysilyl)-propyl]-disulfide, and bis-[2-(triethoxysilyl)-ethyl]-tetrasulfide.
  • the content of the silane coupling agent is preferably 0.1 parts by mass or more and 30 parts by mass or less, more preferably 0.5 parts by mass or more and 20 parts by mass or less, and even more preferably 1.0 parts by mass or more and 15 parts by mass or less, per 100 parts by mass of the filler.
  • the content of the silane coupling agent is within the above range, the interaction between the rubber component and the filler tends to be further improved.
  • the rubber composition of this embodiment may contain, as a rubber component, a rubbery polymer other than the conjugated diene polymer of this embodiment (hereinafter simply referred to as a "rubbery polymer").
  • a rubbery polymer other than the conjugated diene polymer of this embodiment (hereinafter simply referred to as a "rubbery polymer").
  • the conjugated diene polymer of this embodiment and the rubbery polymer are collectively referred to as the "rubber component.”
  • Rubber-like polymers include, but are not limited to, conjugated diene polymers and hydrogenated products thereof, random copolymers of conjugated diene compounds and vinyl aromatic compounds and hydrogenated products thereof, block copolymers of conjugated diene compounds and vinyl aromatic compounds and hydrogenated products thereof, non-diene polymers, natural rubber, etc.
  • Rubber-like polymers include, but are not limited to, styrene-based elastomers such as butadiene rubber and its hydrogenated products, isoprene rubber and its hydrogenated products, styrene-butadiene rubber and its hydrogenated products, styrene-butadiene block copolymers and their hydrogenated products, and styrene-isoprene block copolymers and their hydrogenated products, as well as acrylonitrile-butadiene rubber and its hydrogenated products.
  • styrene-based elastomers such as butadiene rubber and its hydrogenated products, isoprene rubber and its hydrogenated products, styrene-butadiene rubber and its hydrogenated products, styrene-butadiene block copolymers and their hydrogenated products, and styrene-isoprene block copolymers and their hydrogenated products, as well as acrylonitrile-butadiene rubber and
  • Non-diene polymers include, but are not limited to, olefin elastomers such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, ethylene-butene rubber, ethylene-hexene rubber, and ethylene-octene rubber, butyl rubber, brominated butyl rubber, acrylic rubber, fluororubber, silicone rubber, chlorinated polyethylene rubber, epichlorohydrin rubber, ⁇ , ⁇ -unsaturated nitrile-acrylate-conjugated diene copolymer rubber, urethane rubber, and polysulfide rubber.
  • olefin elastomers such as ethylene-propylene rubber, ethylene-propylene-diene rubber, ethylene-butene-diene rubber, ethylene-butene rubber, ethylene-hexene rubber, and ethylene-octene rubber
  • butyl rubber brominated butyl rubber
  • acrylic rubber
  • Natural rubber includes, but is not limited to, smoked sheets such as RSS3-5, SMR, and epoxidized natural rubber.
  • the rubbery polymer may be a modified rubber to which polar functional groups such as hydroxyl groups or amino groups have been added.
  • the rubbery polymer is preferably one or more selected from the group consisting of butadiene rubber, isoprene rubber, styrene-butadiene rubber, natural rubber, and butyl rubber.
  • the weight average molecular weight of the rubber polymer is preferably 2,000 or more and 2,000,000 or less, and more preferably 5,000 or more and 1,500,000 or less.
  • low molecular weight rubber polymers so-called liquid rubbers, can also be used as the rubber polymer. These rubber polymers may be used alone or in combination of two or more types.
  • the content ratio (mass ratio) of the conjugated diene polymer to the rubbery polymer is preferably 10/90 or more and 100/0 or less, more preferably 20/80 or more and 90/10 or less, and even more preferably 30/70 or more and 80/20 or less.
  • the rubber component preferably contains 10 parts by mass or more and 100 parts by mass or less of the conjugated diene polymer of the present embodiment, more preferably 20 parts by mass or more and 90 parts by mass or less, and even more preferably 30 parts by mass or more and 80 parts by mass or less, per 100 parts by mass of the total amount of the rubber component.
  • the proportion of the conjugated diene polymer contained in the rubber component is within the above range, the processability when vulcanized tends to be even better, and the wear resistance of the vulcanized product tends to be even better.
  • the rubber composition of the present embodiment contains a softener component (for example, a rubber softener) in addition to the rubber component, from the viewpoint of further improving its processability.
  • the softener component is not particularly limited, but examples thereof include liquid rubber, resin, and extender oil.
  • the liquid rubber is not particularly limited, but examples thereof include liquid polybutadiene and liquid styrene-butadiene rubber.
  • resins include, but are not limited to, aromatic petroleum resins, coumarone-indene resins, terpene resins, rosin derivatives (including tung oil resins), tall oil, tall oil derivatives, rosin ester resins, natural and synthetic terpene resins, aliphatic hydrocarbon resins, aromatic hydrocarbon resins, mixed aliphatic-aromatic hydrocarbon resins, coumarin-indene resins, phenolic resins, p-tert-butylphenol-acetylene resins, phenol-formaldehyde resins, xylene-formaldehyde resins, monoolefin oligomers, diolefin oligomers, hydrogenated aromatic hydrocarbon resins, cyclic aliphatic hydrocarbon resins, hydrogenated hydrocarbon resins, hydrocarbon resins, hydrogenated tung oil resins, hydrogenated oil resins, and esters of hydrogenated oil resins with monofunctional or polyfunctional alcohols. These resins may be used alone or
  • the breaking strength of the vulcanizate of the conjugated diene polymer composition tends to be further improved.
  • a softener component may be added in addition to the rubber component, but mineral oil or a liquid or low-molecular-weight synthetic softener is preferred.
  • extender oils examples include aromatic oils, naphthenic oils, and paraffin oils.
  • aromatic substitute oils with a polycyclic aromatic (PCA) content of 3% by mass or less according to the IP346 method are preferred.
  • Aroma substitute oils are not particularly limited, but examples include TDAE (Treated Distillate Aromatic Extracts), MES (Mild Extraction Solvate), and RAE (Residual Aromatic Extracts), as shown in Kautschuk Kunststoffe 52(12)799(1999).
  • Mineral oil-based rubber softeners are used to soften rubber, increase its volume, and improve its processability. They are mixtures of aromatic rings, naphthenic rings, and paraffin chains. Among these, softeners in which 50% or more of the total carbon atoms belong to paraffin chains are called paraffinic; softeners in which 30% to 45% of the total carbon atoms belong to naphthenic rings are called naphthenic; and softeners in which more than 30% of the total carbon atoms belong to aromatic carbons are called aromatic.
  • the rubber composition of this embodiment preferably contains a rubber softener with an appropriate aromatic content. The inclusion of such a rubber softener further improves compatibility with conjugated diene polymers.
  • the content of the softener component in the rubber composition of this embodiment is expressed as the total amount of the softener component added in advance to the conjugated diene polymer of this embodiment and the rubbery polymer described above, and the softener component added when the rubber composition is prepared.
  • the content of the softener component is preferably 0 parts by mass or more and 100 parts by mass or less, more preferably 10 parts by mass or more and 90 parts by mass or less, and even more preferably 30 parts by mass or more and 90 parts by mass or less, per 100 parts by mass of the rubber component.
  • the content of the rubber softener be 100 parts by mass or less per 100 parts by mass of the rubber component, bleed-out can be suppressed, and stickiness on the surface of the rubber composition can be further suppressed.
  • the method for producing the rubber composition of this embodiment there are no particular limitations on the method for mixing the conjugated diene polymer of this embodiment, a rubbery polymer other than the conjugated diene polymer of this embodiment, a filler, and, if necessary, a silane coupling agent and a rubber softener.
  • a general mixer such as an open roll, a Banbury mixer, a kneader, a single-screw extruder, a twin-screw extruder, or a multi-screw extruder, and methods in which the components are dissolved and mixed and then the solvent is removed by heating.
  • melt-kneading methods using a roll, a Banbury mixer, a kneader, or an extruder are preferred from the standpoints of productivity and good kneading ability.
  • the rubber component, the filler, the silane coupling agent, and the additives may be kneaded all at once, or they may be mixed in multiple batches.
  • the rubber composition of this embodiment may be vulcanized with a vulcanizing agent to form a vulcanizate.
  • vulcanizing agents include, but are not limited to, radical generators such as organic peroxides and azo compounds, oxime compounds, nitroso compounds, polyamine compounds, sulfur, and sulfur compounds.
  • sulfur compounds include sulfur monochloride, sulfur dichloride, disulfide compounds, and polymeric polysulfur compounds.
  • the content of the vulcanizing agent is preferably 0.01 parts by mass or more and 20 parts by mass or less, and more preferably 0.1 parts by mass or more and 15 parts by mass or less, per 100 parts by mass of the rubber component. Any conventionally known method can be used as the vulcanization method.
  • the vulcanization temperature is preferably 120°C or more and 200°C or less, and more preferably 140°C or more and 180°C or less.
  • a vulcanization accelerator and/or a vulcanization aid may be used as necessary.
  • the vulcanization accelerator a conventionally known material can be used, and examples thereof include, but are not limited to, sulfenamide-based, guanidine-based, thiuram-based, aldehyde-amine-based, aldehyde-ammonia-based, thiazole-based, thiourea-based, and dithiocarbamate-based vulcanization accelerators.
  • examples of the vulcanization aid include, but are not limited to, zinc oxide and stearic acid.
  • the content of each of the vulcanization accelerator and the vulcanization aid per 100 parts by mass of the rubber component is preferably 0.01 parts by mass or more and 20 parts by mass or less, and more preferably 0.1 parts by mass or more and 15 parts by mass or less.
  • the rubber composition of this embodiment may contain various additives other than those mentioned above, such as softeners and fillers, heat stabilizers, antistatic agents, weather stabilizers, antioxidants, colorants, and lubricants, as long as they do not impair the effects of this embodiment.
  • softeners can be used.
  • Specific fillers include, but are not limited to, calcium carbonate, magnesium carbonate, aluminum sulfate, and barium sulfate.
  • Known materials can be used for the heat stabilizers, antistatic agents, weather stabilizers, antioxidants, colorants, and lubricants.
  • the rubber composition of the present embodiment is suitably used as a rubber composition for tires.
  • the tire of the present embodiment include, but are not limited to, agricultural machine tires, construction vehicle tires, industrial vehicle tires, truck and bus tires, light truck tires, passenger car tires, etc.
  • Passenger car tires include various types of tires such as fuel-efficient tires, all-season tires, high-performance tires, and studless tires, and the rubber composition of the present embodiment can be suitably used in each part of the tire such as the tread, carcass, sidewall, and bead portion.
  • the rubber composition of this embodiment has industrial applicability, including vibration-damping rubber, vibration-isolating rubber, conveyor belts, shoe soles such as outsoles, automotive weather strips, packings and gaskets, sealants, waterproof sheets, engine mounts, air springs, rubber gloves, medical and sanitary products, hoses for industrial and various uses, battery cases, adhesives, electrical wire coatings, window frame rubber, rubber stoppers, rubber rollers, and materials for various industrial products.
  • industrial applicability including vibration-damping rubber, vibration-isolating rubber, conveyor belts, shoe soles such as outsoles, automotive weather strips, packings and gaskets, sealants, waterproof sheets, engine mounts, air springs, rubber gloves, medical and sanitary products, hoses for industrial and various uses, battery cases, adhesives, electrical wire coatings, window frame rubber, rubber stoppers, rubber rollers, and materials for various industrial products.
  • the residence time of the 1,3-butadiene phase in the decanter was 30 minutes.
  • the aqueous phase separated in the decanter was introduced into a 1,3-butadiene removal tank, mixed with steam and heated to 89° C.
  • the total pressure was set to 0.01 MPaG, and 1,3-butadiene was separated from the aqueous phase.
  • Polymerization inhibitor removal step Furthermore, a 10% aqueous caustic soda solution was mixed with the 1,3-butadiene that had been subjected to the oxygen removal step using an oxygen scavenger at a circulation flow rate of 1 m 3 /hr using a packed tower equipped with Paul rings, and liquid-liquid extraction was carried out. The mixture was then transferred to another decanter, where it was separated into a 1,3-butadiene phase and an aqueous phase. The residence time of the 1,3-butadiene phase in the other decanter was 60 minutes. In the polymerization inhibitor removal step, the operation was carried out under the conditions of a liquid temperature of 30° C. and a decanter pressure of 1.0 MPaG.
  • Styrene to be used in the polymerization of the conjugated diene polymer was purified by the following process.
  • ⁇ -alumina formed into a cylindrical shape of 3 mm ⁇ 3 mm was impregnated with a 0.6% aqueous palladium chloride solution and dried for one day at 100°C.
  • the dried product was then reduced in a hydrogen stream at 400°C for 16 hours to obtain a hydrogenation catalyst with a composition of Pd (0.3%)/ ⁇ -Al 2 O 3.
  • 2000 g of the obtained hydrogenation catalyst was packed into a tubular reactor and circulated for 8 hours while maintaining the catalyst temperature at 80°C to obtain purified styrene.
  • Normal hexane used in the polymerization of the conjugated diene polymer was purified by the following process.
  • a tubular reactor was filled with 2000 g of molecular sieve 13-X (Union Showa) and circulated at room temperature for 24 hours to obtain purified normal hexane.
  • the eluent used was 0.4 wt % triethylamine-THF (tetrahydrofuran).
  • the columns used were three "TSKgel SuperMultiporeHZ-H” columns manufactured by Tosoh Corporation connected together, and a "TSKguardcolumn SuperMP(HZ)-H” column manufactured by Tosoh Corporation connected in front of them as a guard column.
  • 10 mg of the sample to be measured was dissolved in 10 mL of THF to prepare a measurement solution, and 10 ⁇ L of the measurement solution was injected into a GPC measurement device and measured under conditions of an oven temperature of 40° C. and a THF flow rate of 0.35 mL/min.
  • sample solution for measurement 10 mg of the measurement sample and 5 mg of standard polystyrene were dissolved in 10 mL of THF (tetrahydrofuran) to prepare a measurement sample solution.
  • GPC measurement conditions using a polystyrene column Using a Tosoh Corporation "HLC-8320GPC" column, 10 ⁇ L of the sample solution was injected into the column using 0.4 wt % triethylamine-THF as the eluent, and a chromatogram was obtained using an RI detector under the following conditions: column oven temperature 40°C, THF flow rate 0.35 mL/min.
  • the eluent used was THF containing 5 mmol/L triethylamine.
  • the columns used were "TSKgel G4000HXL,”"TSKgelG5000HXL,” and “TSKgel G6000HXL,” both manufactured by Tosoh Corporation.
  • the degree of branching (Bn) at the absolute molecular weight of (Mw1+Mw2)/2 was calculated according to the above-mentioned method for measuring the degree of branching (Bn).
  • the oxidation onset temperature of a conjugated diene polymer sample was measured using a thermogravimetric differential thermal analyzer (STA 7200R V, Hitachi).
  • the oxidation onset temperature was defined as the temperature at which an endothermic peak was observed when the sample was heated from 30°C to 500°C at a rate of 10°C/min in an air atmosphere.
  • the eluent used was THF containing 5 mmol/L triethylamine.
  • the columns used were "TSKgel G4000HXL,”"TSKgelG5000HXL,” and “TSKgel G6000HXL,” both manufactured by Tosoh Corporation.
  • the polymerization reactor was prepared by connecting two tank-type pressure vessels each having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with an agitator, which was a tank-type reactor equipped with an agitator, and a jacket for temperature control.
  • tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "A" in the table) as a modifier was continuously added at a rate of 0.0230 mmol/min to the polymer solution flowing out from the outlet of the reactor, and the polymer solution to which the modifier had been added was mixed by passing through a static mixer, thereby causing a modification reaction.
  • an antioxidant BHT was dissolved in hexane so that the amount would be 0.2 g per 100 g of polymer, and stearic acid was dissolved in hexane so that the amount would be 0.03 g per 100 g of polymer, and then these were continuously added to the polymer solution to terminate the polymerization reaction.
  • the solvent was removed from the conjugated diene polymer solution by steam stripping to obtain a conjugated diene polymer A1.
  • Various measurements were carried out, and the results are shown in Table 1.
  • the resulting polymer solution was then transferred to a tank-type pressure vessel having an internal volume of 100 L.
  • the polymerization reactor was prepared by connecting two tank-type pressure vessels each having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with an agitator, which was a tank-type reactor equipped with an agitator, and a jacket for temperature control.
  • 1,3-butadiene from which water had been removed in advance, was mixed at a rate of 21.2 g/min, styrene at 7.1 g/min, and n-hexane at 190 g/min.
  • the modifying agent 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasilolidine (abbreviated as "B” in the Table), was continuously added at a rate of 0.0336 mmol/min to the polymer solution that had flowed out from the outlet of the reactor, and the polymer solution to which the modifying agent had been added was mixed by passing through a static mixer, thereby causing a modification reaction.
  • B 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasilolidine
  • an antioxidant BHT was dissolved in hexane so that the amount would be 0.2 g per 100 g of polymer, and stearic acid was dissolved in hexane so that the amount would be 0.03 g per 100 g of polymer, and then these were continuously added to the polymer solution to terminate the polymerization reaction.
  • the solvent was removed from the conjugated diene polymer solution by steam stripping to obtain a conjugated diene polymer A2.
  • Various measurements were carried out, and the results are shown in Table 1.
  • the resulting polymer solution was then transferred to a tank-type pressure vessel having an internal volume of 100 L.
  • the polymerization reactor was prepared by connecting two tank-type pressure vessels each having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with an agitator, which was a tank-type reactor equipped with an agitator, and a jacket for temperature control.
  • 1,3-butadiene from which water had been removed in advance, was mixed at a rate of 23.1 g/min, styrene at 7.7 g/min, and n-hexane at 206 g/min.
  • trimethoxy(4-vinylphenyl)silane as a branching agent was supplied from the bottom of the first reactor at a rate of 0.0084 mmol/min, and further trimethoxy(4-vinylphenyl)silane as a branching agent was supplied from the bottom of the second reactor at a rate of 0.0169 mmol/min, thereby carrying out a polymerization branching step.
  • the polymerization reactor was prepared by connecting two tank-type pressure vessels each having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with an agitator, which was a tank-type reactor equipped with an agitator, and a jacket for temperature control.
  • 1,3-butadiene from which water had been removed in advance, was mixed at a rate of 21.2 g/min, styrene at 7.1 g/min, and n-hexane at 208 g/min.
  • tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "A" in the table) as a modifier was continuously added at a rate of 0.0287 mmol/min to the polymer solution flowing out from the outlet of the reactor, and the polymer solution to which the modifier had been added was mixed by passing through a static mixer, thereby causing a modification reaction.
  • an antioxidant BHT was dissolved in hexane so that the amount would be 0.2 g per 100 g of polymer, and stearic acid was dissolved in hexane so that the amount would be 0.03 g per 100 g of polymer, and then these were continuously added to the polymer solution to terminate the polymerization reaction.
  • the solvent was removed from the conjugated diene polymer solution by steam stripping to obtain a conjugated diene polymer A4.
  • Various measurements were carried out, and the results are shown in Table 1.
  • the resulting polymer solution was then transferred to a tank-type pressure vessel having an internal volume of 100 L.
  • the polymerization reactor was prepared by connecting two tank-type pressure vessels each having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with an agitator, which was a tank-type reactor equipped with an agitator, and a jacket for temperature control.
  • the modifying agent 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasilolidine (abbreviated as "B” in the Table), was continuously added at a rate of 0.0088 mmol/min to the polymer solution that had flowed out from the outlet of the reactor, and the polymer solution to which the modifying agent had been added was mixed by passing through a static mixer, thereby causing a modification reaction.
  • B 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasilolidine
  • an antioxidant BHT was dissolved in hexane so that the amount would be 0.2 g per 100 g of polymer, and stearic acid was dissolved in hexane so that the amount would be 0.03 g per 100 g of polymer, and then these were continuously added to the polymer solution to terminate the polymerization reaction.
  • the solvent was removed from the conjugated diene polymer solution by steam stripping to obtain a conjugated diene polymer A5.
  • Various measurements were carried out, and the results are shown in Table 1.
  • the resulting polymer solution was then transferred to a tank-type pressure vessel having an internal volume of 100 L.
  • the polymerization reactor was prepared by connecting two tank-type pressure vessels each having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with an agitator, which was a tank-type reactor equipped with an agitator, and a jacket for temperature control.
  • 1,3-butadiene from which water had been removed in advance, was mixed at a rate of 23.1 g/min, styrene at 7.7 g/min, and n-hexane at 206 g/min.
  • trimethoxy(4-vinylphenyl)silane was fed as a branching agent from the bottom of the second reactor at a rate of 0.0108 mmol/min to carry out a polymerization branching step.
  • an antioxidant (BHT) and stearic acid were dissolved in hexane so that the amounts were 0.2 g per 100 g of the polymer and 0.03 g per 100 g of the polymer, respectively, and then these were continuously added to terminate the polymerization reaction.
  • the solvent was removed from the conjugated diene polymer solution by steam stripping to obtain a conjugated diene polymer A6.
  • Various measurements were carried out, and the results are shown in Table 1.
  • the resulting polymer solution was then transferred to a tank-type pressure vessel having an internal volume of 100 L.
  • the polymerization reactor was prepared by connecting two tank-type pressure vessels each having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with an agitator, which was a tank-type reactor equipped with an agitator, and a jacket for temperature control.
  • the modifying agent 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasilolidine (abbreviated as "B" in the Table), was continuously added at a rate of 0.0460 mmol/min to the polymer solution that had flowed out from the outlet of the reactor, and the polymer solution to which the modifying agent had been added was mixed by passing through a static mixer, thereby causing a modification reaction.
  • B 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasilolidine
  • an antioxidant BHT was dissolved in hexane so that the amount would be 0.2 g per 100 g of polymer, and stearic acid was dissolved in hexane so that the amount would be 0.03 g per 100 g of polymer, and then these were continuously added to the polymer solution to terminate the polymerization reaction.
  • the solvent was removed from the conjugated diene polymer solution by steam stripping to obtain a conjugated diene polymer A7.
  • Various measurements were carried out, and the results are shown in Table 1.
  • the resulting polymer solution was then transferred to a tank-type pressure vessel having an internal volume of 100 L.
  • the polymerization reactor was prepared by connecting two tank-type pressure vessels each having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with an agitator, which was a tank-type reactor equipped with an agitator, and a jacket for temperature control.
  • tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine (abbreviated as "A" in the table) as a modifier was continuously added at a rate of 0.0042 mmol/min to the polymer solution flowing out from the outlet of the reactor, and the polymer solution to which the modifier had been added was mixed by passing through a static mixer, thereby causing a modification reaction.
  • an antioxidant BHT was dissolved in hexane so that the amount would be 0.2 g per 100 g of polymer, and stearic acid was dissolved in hexane so that the amount would be 0.03 g per 100 g of polymer, and then these were continuously added to the polymer solution to terminate the polymerization reaction.
  • the solvent was removed from the conjugated diene polymer solution by steam stripping to obtain a conjugated diene polymer A8.
  • Various measurements were carried out, and the results are shown in Table 1.
  • the resulting polymer solution was then transferred to a tank-type pressure vessel having an internal volume of 100 L.
  • the polymerization reactor was prepared by connecting two tank-type pressure vessels each having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with an agitator, which was a tank-type reactor equipped with an agitator, and a jacket for temperature control.
  • 1,3-butadiene from which water had been removed in advance, was mixed at a rate of 23.1 g/min, styrene at 7.7 g/min, and n-hexane at 206 g/min.
  • trimethoxy(4-vinylphenyl)silane as a branching agent was supplied from the bottom of the first reactor at a rate of 0.0270 mmol/min, and further trimethoxy(4-vinylphenyl)silane as a branching agent was supplied from the bottom of the second reactor at a rate of 0.0271 mmol/min, thereby carrying out a polymerization branching step.
  • the polymerization reactor was prepared by connecting two tank-type pressure vessels each having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with an agitator, which was a tank-type reactor equipped with an agitator, and a jacket for temperature control.
  • 1,3-butadiene from which water had been removed in advance, was mixed at a rate of 21.2 g/min, styrene at 7.1 g/min, and n-hexane at 208 g/min.
  • the polymerization reactor was prepared by connecting two tank-type pressure vessels each having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with an agitator, which was a tank-type reactor equipped with an agitator, and a jacket for temperature control.
  • 1,3-butadiene from which water had been removed in advance, was mixed at a rate of 21.2 g/min, styrene at 7.1 g/min, and n-hexane at 208 g/min.
  • the modifying agent 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasilolidine (abbreviated as "B” in the Table), was continuously added at a rate of 0.0088 mmol/min to the polymer solution that had flowed out from the outlet of the reactor, and the polymer solution to which the modifying agent had been added was mixed by passing through a static mixer, thereby causing a modification reaction.
  • B 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasilolidine
  • an antioxidant (BHT) was dissolved in hexane so that the amount of the antioxidant was 0.2 g per 100 g of polymer, and stearic acid was dissolved in hexane so that the amount of the antioxidant was 2.10 g per 100 g of polymer, and then these were continuously added to the modified polymer solution to terminate the polymerization reaction.
  • the solvent was removed from the conjugated diene polymer solution by steam stripping to obtain a conjugated diene polymer A11.
  • Various measurements were carried out, and the results are shown in Table 1.
  • the resulting polymer solution was then transferred to a tank-type pressure vessel having an internal volume of 100 L.
  • the polymerization reactor was prepared by connecting two tank-type pressure vessels each having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with an agitator, which was a tank-type reactor equipped with an agitator, and a jacket for temperature control.
  • 1,3-butadiene from which water had been removed in advance, was mixed at a rate of 16.2 g/min, styrene at 10.0 g/min, and n-hexane at 196 g/min.
  • trimethoxy(4-vinylphenyl)silane was fed as a branching agent from the bottom of the second reactor at a rate of 0.0166 mmol/min to carry out a polymerization branching step.
  • an antioxidant (BHT) and stearic acid were dissolved in hexane so that the amounts were 0.2 g per 100 g of the polymer and 0.03 g per 100 g of the polymer, respectively, and then these were continuously added to terminate the polymerization reaction.
  • the solvent was removed from the conjugated diene polymer solution by steam stripping to obtain a conjugated diene polymer A12.
  • Various measurements were carried out, and the results are shown in Table 1.
  • the resulting polymer solution was then transferred to a tank-type pressure vessel having an internal volume of 100 L.
  • the polymerization reactor was prepared by connecting two tank-type pressure vessels each having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with an agitator, which was a tank-type reactor equipped with an agitator, and a jacket for temperature control.
  • 1,3-butadiene from which water had been removed in advance, was mixed at a rate of 16.2 g/min, styrene at 10.0 g/min, and n-hexane at 196 g/min.
  • trimethoxy(4-vinylphenyl)silane was fed as a branching agent from the bottom of the second reactor at a rate of 0.0166 mmol/min to carry out a polymerization branching step.
  • an antioxidant (BHT) and stearic acid were dissolved in hexane so that the amounts were 0.2 g per 100 g of the polymer and 0.03 g per 100 g of the polymer, respectively, and then these were continuously added to terminate the polymerization reaction.
  • the solvent was removed from the conjugated diene polymer solution by steam stripping to obtain a conjugated diene polymer A13.
  • Various measurements were carried out, and the results are shown in Table 1.
  • the resulting polymer solution was then transferred to a tank-type pressure vessel having an internal volume of 100 L.
  • the polymerization reactor was prepared by connecting two tank-type pressure vessels each having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with an agitator, which was a tank-type reactor equipped with an agitator, and a jacket for temperature control.
  • 1,3-butadiene from which water had been removed in advance, was mixed at a rate of 25.0 g/min, styrene at 8.3 g/min, and n-hexane at 205 g/min.
  • the polymerization reactor was prepared by connecting two tank-type pressure vessels each having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with an agitator, which was a tank-type reactor equipped with an agitator, and a jacket for temperature control.
  • 1,3-butadiene from which water had been removed in advance, was mixed at a rate of 25.0 g/min, styrene at 8.3 g/min, and n-hexane at 205 g/min.
  • the polymerization reactor was prepared by connecting two tank-type pressure vessels each having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with an agitator, which was a tank-type reactor equipped with an agitator, and a jacket for temperature control.
  • 1,3-butadiene from which water had been removed in advance, was mixed at a rate of 25.0 g/min, styrene at 8.3 g/min, and n-hexane at 205 g/min.
  • the polymerization reactor was prepared by connecting two tank-type pressure vessels each having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with an agitator, which was a tank-type reactor equipped with an agitator, and a jacket for temperature control.
  • 1,3-butadiene from which water had been removed in advance, was mixed at a rate of 25.0 g/min, styrene at 8.3 g/min, and n-hexane at 205 g/min.
  • the modifying agent 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasilolidine (abbreviated as "B" in the Table), was continuously added at a rate of 0.0520 mmol/min to the polymer solution that had flowed out from the outlet of the reactor, and the polymer solution to which the modifying agent had been added was mixed by passing through a static mixer, thereby causing a modification reaction.
  • B 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasilolidine
  • an antioxidant BHT was dissolved in hexane so that the amount would be 0.2 g per 100 g of polymer, and stearic acid was dissolved in hexane so that the amount would be 0.03 g per 100 g of polymer, and then these were continuously added to the polymer solution to terminate the polymerization reaction.
  • the solvent was removed from the conjugated diene polymer solution by steam stripping to obtain a conjugated diene polymer B4.
  • Various measurements were carried out, and the results are shown in Table 1.
  • the resulting polymer solution was then transferred to a tank-type pressure vessel having an internal volume of 100 L.
  • the polymerization reactor was prepared by connecting two tank-type pressure vessels each having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with an agitator, which was a tank-type reactor equipped with an agitator, and a jacket for temperature control.
  • the polymerization reactor was prepared by connecting two tank-type pressure vessels each having an internal volume of 10 L, an internal height (L) to diameter (D) ratio (L/D) of 4.0, an inlet at the bottom and an outlet at the top, and equipped with an agitator, which was a tank-type reactor equipped with an agitator, and a jacket for temperature control.
  • 1,3-butadiene from which water had been removed in advance, was mixed at a rate of 16.2 g/min, styrene at 10.0 g/min, and n-hexane at 196 g/min.
  • A Tetrakis(3-trimethoxysilylpropyl)-1,3-propanediamine
  • B 2,2-dimethoxy-1-(3-(trimethoxysilyl)propyl)-1,2-azasilolidine
  • Branching agent Trimethoxy(4-vinylphenyl)silane
  • Example 1 Conjugated Diene Polymer C1
  • Conjugated diene polymers C2 to C20 were obtained by varying the combination of conjugated diene polymer A and conjugated diene polymer B used and the content of conjugated diene polymer A in conjugated diene polymer C as shown in Table 2, using the same production method as for conjugated diene polymer C1.
  • conjugated diene polymer C21 was obtained as Comparative Example 9 using ESBR1500 manufactured by ENEOS Materials Corporation. Various measurements were carried out and the results are shown in Table 2.
  • the raw rubber conjugated diene polymers C1-C21
  • silica-based inorganic filler silane coupling agent
  • process oil was kneaded for 4 minutes in the first stage of mixing at a filling rate of 65% and a rotor rotation speed of 30-50 rpm.
  • the kneader temperature was controlled during this process, and the discharge temperature (compound) was kept at 155-160°C, yielding a conjugated diene polymer composition.
  • the compound obtained above was cooled to room temperature, and then carbon black, zinc oxide, stearic acid, wax, and antioxidant were added and mixed in the kneader for 3 minutes.
  • the discharge temperature (compound) was also adjusted to 155-160°C using the mixer's temperature control. Then, immediately after the compound was discharged from the kneader, it was passed through a 10-inch ⁇ open roll six times to produce a sheet-shaped unvulcanized rubber composition, which was then cooled and its processability evaluated.
  • the unvulcanized composition was heated in an oven at 70°C for 30 minutes, and then in the third stage of mixing, sulfur and a vulcanization accelerator were added and mixed using a 10-inch diameter open roll set at 70°C to obtain a composition. The remainder of the composition was then vulcanized and molded in a vulcanization press at 160°C for 20 minutes to obtain a vulcanized product. After vulcanization, the physical properties of the rubber composition were measured. The results of the physical property measurements are shown in Table 3 below.
  • the Mooney viscosity index of the compound is 115 or more.
  • the Mooney viscosity index of the compound is 105 or more and less than 115.
  • the Mooney viscosity index of the compound is 95 or more and less than 105.
  • the Mooney viscosity index of the compound is 85 or more and less than 95.
  • the Mooney viscosity index of the compound is less than 85.
  • the hardness of the vulcanized rubber composition was measured at 25° C. using a Type A hardness tester in accordance with JIS K6253 (Shore A measurement). Using the hardness value of Comparative Example 10 as the standard, the steering stability was evaluated according to the following [Evaluation Criteria for Steering Stability]. The larger the value, the harder the tire and the better the handling stability. [Evaluation criteria for steering stability] 5: The hardness value is 3.1 or more higher than the hardness value of Comparative Example 10. 4: The hardness value is 2.1 to 3.0 greater than the hardness value of Comparative Example 10. 3: The hardness value is ⁇ 2.0 relative to the hardness value of Comparative Example 10. 2: The hardness value is 2.1 to 3.0 smaller than the hardness value of Comparative Example 10. 1: The hardness value is smaller than the hardness value of Comparative Example 10 by 3.1.
  • the amount of wear of the vulcanized rubber composition was measured using an Acron abrasion tester (manufactured by Yasuda Seiki Seisakusho Co., Ltd.) under a load of 44.4 N and 1000 revolutions in accordance with JIS K6264-2.
  • the result of Comparative Example 10 was set as 100 and the abrasion resistance was evaluated according to the following [Evaluation Criteria for Abrasion Resistance]. A larger index indicates better abrasion resistance.
  • the conjugated diene polymer of the present invention has good bale moldability, excellent processability when vulcanized, and high hardness when vulcanized, as well as good abrasion resistance and fuel economy, demonstrating an excellent balance of performance.
  • the conjugated diene polymer and rubber composition of the present invention have industrial applicability in applications such as tires, resin modification, automotive interior and exterior parts, vibration-proof rubber, belts, footwear, foams, and various industrial products.

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  • Chemical & Material Sciences (AREA)
  • Health & Medical Sciences (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Medicinal Chemistry (AREA)
  • Polymers & Plastics (AREA)
  • Organic Chemistry (AREA)
  • General Chemical & Material Sciences (AREA)
  • Compositions Of Macromolecular Compounds (AREA)
  • Addition Polymer Or Copolymer, Post-Treatments, Or Chemical Modifications (AREA)

Abstract

L'invention concerne un polymère à base de diène conjugué satisfaisant les exigences (1) à (5) suivantes.　(1) Donner, lors d'un examen par chromatographie par perméation de gel (CPG), une courbe de distribution de poids moléculaire qui est unimodale et a un épaulement dans une région dans la courbe de distribution de poids moléculaire qui s'étend du sommet de pic au point d'extrémité de pic côté poids moléculaire supérieur.　(2) Avoir un poids moléculaire moyen en poids (Mw) déterminé par CPG compris entre 200 000 et 1 000 000.　(3) Avoir une distribution de poids moléculaire comprise entre 1,7 et 3,0.　(4) Avoir un degré de modification inférieur à 40 % en masse.　(5) Lorsque le poids moléculaire absolu au niveau d'un premier point d'inflexion dans une région dans une courbe de poids moléculaire absolu qui se trouve sur le côté de poids moléculaire supérieur du sommet de pic, la courbe de poids moléculaire absolu étant obtenue par un procédé d'analyse par diffusion de lumière/CPG équipé d'un viscosimètre, est exprimé par Mw1 et le poids moléculaire absolu au niveau d'un point d'extrémité de pic dans la région est exprimé par Mw2, alors le degré de ramification (Bn) au poids moléculaire absolu de (Mw1+Mw2)/2 est supérieur ou égal à 4.　(6) Avoir un facteur de retrait (g') au poids moléculaire de sommet de pic (Mp) obtenu par le procédé d'analyse par diffusion de lumière/CPG équipé d'un viscosimètre de 0,90 ou plus.
PCT/JP2025/008609 2024-03-12 2025-03-07 Polymère à base de diène conjugué, procédé de production d'un polymère à base de diène conjugué, et composition de caoutchouc Pending WO2025192482A1 (fr)

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Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018164053A1 (fr) * 2017-03-07 2018-09-13 旭化成株式会社 Polymère de diène conjugué modifié, composition de polymère et composition de caoutchouc
JP2020037676A (ja) * 2018-08-30 2020-03-12 旭化成株式会社 変性共役ジエン系重合体組成物
WO2021044921A1 (fr) * 2019-09-05 2021-03-11 旭化成株式会社 Polymère de diène conjugué, procédé de production de polymère de diène conjugué, composition de polymère de diène conjugué et composition de caoutchouc
JP2021172722A (ja) * 2020-04-23 2021-11-01 旭化成株式会社 液状共役ジエン系ゴム、ブレンドポリマー、伸展共役ジエン系ゴム、及びブレンドポリマーの製造方法

Patent Citations (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
WO2018164053A1 (fr) * 2017-03-07 2018-09-13 旭化成株式会社 Polymère de diène conjugué modifié, composition de polymère et composition de caoutchouc
JP2020037676A (ja) * 2018-08-30 2020-03-12 旭化成株式会社 変性共役ジエン系重合体組成物
WO2021044921A1 (fr) * 2019-09-05 2021-03-11 旭化成株式会社 Polymère de diène conjugué, procédé de production de polymère de diène conjugué, composition de polymère de diène conjugué et composition de caoutchouc
JP2021172722A (ja) * 2020-04-23 2021-11-01 旭化成株式会社 液状共役ジエン系ゴム、ブレンドポリマー、伸展共役ジエン系ゴム、及びブレンドポリマーの製造方法

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