JP6338914B2 - Process for producing conjugated diene polymer - Google Patents

Description

  The present invention relates to a method for producing a conjugated diene polymer.

  In recent years, thermoplastic elastomers, which are soft materials having rubber elasticity, do not require a vulcanization process, and can be molded and recycled in the same manner as thermoplastic resins, are widely used in a wide range of fields.

  For example, a polymer of a conjugated diene monomer such as 1,3-butadiene or isoprene, or a vinyl aromatic monomer such as styrene copolymerizable with the conjugated diene monomer and the conjugated diene monomer. These copolymers are very important as impact-resistant transparent resins or modifiers for polyolefins and polystyrene resins.

  Moreover, the hydrogenated polymer obtained by adding hydrogen to the olefinic double bond portion contained in the conjugated diene polymer has a feature of excellent weather resistance. Taking advantage of this feature, hydrogenated polymers are used in automobile parts, home appliance parts, wire coverings, medical parts, sundries, footwear and the like.

  Generally, the conjugated diene polymer is produced by living anionic polymerization using an alkyl lithium as an initiator. Further, in the case of obtaining a hydrogenated polymer, a hydrogenation reaction (hereinafter also referred to as “hydrogenation reaction”) is performed on the olefinic double bond portion after polymerization by using a Group VIII or Group IV metal as a catalyst. I do.

  Various methods for hydrogenating a polymer having an olefinic double bond have been reported. For example, suitable compounds such as compounds of Group VIII of the periodic table, particularly nickel or cobalt compounds and alkylaluminum compounds can be used. A hydrogenation method using a catalyst combined with a reducing agent is known. In addition, a titanium compound which is a group IV metal of the periodic table, for example, a catalyst in which a suitable reducing agent such as a bis (cyclopentadienyl) titanium compound and an alkylaluminum compound is combined is used. A method for hydrogenating an unsaturated double bond of a coalescence is known.

  As described above, thermoplastic elastomers, particularly conjugated diene polymers such as those described above, and hydrogenated polymers thereof include metal residues (hereinafter referred to as “catalyst residues”) derived from initiators and hydrogenation catalysts. Will be included). The metal residue in the polymer solution must be removed efficiently in the manufacturing process because it leads to various quality degradations such as product roughness, surface roughness, coloring, and turbidity.

  Therefore, several proposals have been made as methods for removing metal residues remaining in the polymer solution. For example, Patent Document 1 discloses a method of removing a lithium residue in a polymer solution by vigorously mixing the polymer solution and water using a rotary disperser having a meshing structure.

  Moreover, in patent document 2, lithium polymer and aluminum residue in a polymer solution are mixed by vigorously mixing a polymer solution, an inorganic strong acid, and water containing an organic carboxylic acid using a rotating disperser having a meshing structure. A method of removing is disclosed.

  Furthermore, Patent Document 3 discloses a method of removing nickel residues and aluminum residues by treating a water-insoluble resin solution with an organic acid aqueous solution in a hydrogen atmosphere. In addition to the above, many prior literatures have been disclosed regarding the removal of metal residues such as lithium, nickel, and aluminum.

  On the other hand, there has been almost no report on a method for removing a titanium residue. For example, Patent Document 4 discloses a method of removing a titanium residue by steam stripping a solvent or slurry of a rubber-like polymer to which a phosphonate, a phosphate ester salt and water are added. Patent Document 5 discloses removal of a titanium residue using an inorganic acid, an alcohol, and water.

Japanese Patent Laid-Open No. 6-136034 JP 2002-356509 A JP-A-8-269126 Japanese Patent Application No. 8-340389 JP 2002-167406 A

  Metal residues that cause product quality degradation need to be removed from the polymer solution. However, as described above, in the prior art, there are almost no reports of removal methods showing high effects on a plurality of metal residues.

  For example, in the method described in Patent Document 4, since a large amount of steam is required in the steam stripping process, the running cost becomes high. Furthermore, since a phosphonate or phosphate ester salt is used, waste liquid treatment becomes a problem. In addition, the method described in Patent Document 5 has a problem of productivity, for example, it takes a long time to stir and separate the polymer solution and the alcohol in the process of removing the metal. Further, it is necessary to use a large amount of alcohol and water, and waste liquid treatment becomes a big problem in industrial production. Further, even if alcohol or water is reused, a large-scale purification facility is required.

  The present invention has been made in view of the above-described problems of the prior art, and efficiently removes a metal residue from a polymer solution containing a metal residue, has excellent color tone, and has a low turbidity. It is an object of the present invention to provide a method for producing a conjugated diene polymer that can be obtained.

  As a result of intensive studies to solve the above problems, the present inventors have added a surfactant and an inorganic acid to a polymer solution containing a metal residue, and further added a polar liquid to the polymer solution. The present inventors have found that metal residues can be separated and removed effectively and completed the present invention.

That is, the present invention is as follows.
[1]
Preparing a conjugated diene polymer solution comprising at least one metal selected from the group consisting of lithium, titanium, and aluminum, and a conjugated diene polymer;
To the conjugated diene polymer solution, at least one inorganic acid (b) selected from the group consisting of surfactant (a), sulfuric acid, hydrochloric acid and nitric acid, and polar liquid (c) are added, mixed and mixed. Step 2 for obtaining a liquid;
Removing the surfactant (a), the inorganic acid (b), and the polar liquid (c) from the mixed solution, and
Wherein the surfactant (a) is seen containing a nonionic surfactant,
Step 2 is
Step 2-1 for mixing the conjugated diene polymer solution and the surfactant (a) to obtain a first mixed solution;
Step 2-2 for mixing the first mixed solution and the inorganic acid (b) to obtain a second mixed solution;
Step 2-3 of mixing the second liquid mixture and the polar liquid (c) to obtain the liquid mixture;
In order,
A method for producing a conjugated diene polymer.
[2]
The method for producing a conjugated diene polymer according to [1] above, wherein in the step 1, the conjugated diene polymer solution contains the lithium and / or the titanium.
[3]
After the step 2-2, the metal is in a soluble state in the polar liquid (c) in the second liquid mixture.
The method for producing a conjugated diene polymer according to [1] or [2] above.
[4]
In the step 1, the conjugated diene polymer solution contains the titanium,
After the step 2-2, in the second mixed liquid, the titanium is in a soluble state in the polar liquid (c).
The method for producing a conjugated diene polymer according to any one of [1] to [3] above.
[5]
The inorganic acid (b) contains sulfuric acid,
The method for producing a conjugated diene polymer according to any one of [1] to [4] .
[6]
The polar liquid (c) contains water;
The method for producing a conjugated diene polymer according to any one of [1] to [5] above.
[7]
In the step 2-3, mixing is performed under the following conditions using a rotary disperser having a meshing structure.
The method for producing a conjugated diene polymer according to any one of [1] to [6] above.
P / V value ≧ 3 × 10 ⁴
(P: Disperser power (kw), V: Volume of mixing section (m ³ ))
Peripheral speed (2πr · n) ≧ 5
(R: radius of rotor outermost teeth (m), n: number of rotations of rotor (s ⁻¹ )
[8]
In the step 3, by applying a relative acceleration of 100 G or more to the mixed solution using a centrifuge, the surfactant (a), the inorganic acid (b), and the polar liquid ( The method for producing a conjugated diene polymer according to any one of [1] to [7] , wherein c) is removed.
[9]
The method for producing a conjugated diene polymer according to [8] above, wherein the centrifuge is a disk-type centrifuge.
[10]
In the said process 2, the alcohol concentration in the said liquid mixture is 2000 ppm or less, The manufacturing method of the conjugated diene type polymer as described in any one of the preceding clauses [1]- [9] .

  According to the present invention, production of a conjugated diene polymer capable of efficiently removing a metal residue from a polymer solution containing the metal residue and obtaining a conjugated diene polymer having excellent color tone and low turbidity. A method can be provided.

  Hereinafter, a mode for carrying out the present invention (hereinafter referred to as “the present embodiment”) will be described in detail. The present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist.

[Method for producing conjugated diene polymer]
The production method of the conjugated diene polymer of this embodiment is as follows:
Preparing a conjugated diene polymer solution comprising at least one metal selected from the group consisting of lithium, titanium, and aluminum, and a conjugated diene polymer;
To the conjugated diene polymer solution, at least one inorganic acid (b) selected from the group consisting of surfactant (a), sulfuric acid, hydrochloric acid and nitric acid, and polar liquid (c) are added, mixed and mixed. Step 2 for obtaining a liquid;
And a step 3 of removing the surfactant (a), the inorganic acid (b), and the polar liquid (c) from the mixed solution.

[Step 1]
Step 1 is a step of preparing a conjugated diene polymer solution containing at least one metal selected from the group consisting of lithium, titanium, and aluminum and a conjugated diene polymer.

  “Metal” includes simple metals, metal compounds, and ions, and these are collectively referred to as metal residues. The metal contained in the conjugated diene polymer solution is preferably lithium and / or titanium, more preferably titanium, from the viewpoint of deashing efficiency and productivity.

(Conjugated diene polymer solution)
The conjugated diene polymer solution used in this embodiment is obtained by polymerizing at least a conjugated diene monomer. Such a conjugated diene polymer solution is not particularly limited, and can be obtained, for example, by polymerizing at least a conjugated diene monomer with a polymerization initiator in the solution. The conjugated diene polymer in the conjugated diene polymer solution may be hydrogenated.

  The conjugated diene polymer solution used in the present embodiment contains at least one metal selected from the group consisting of lithium, titanium, and aluminum. Here, at least one metal selected from the group consisting of lithium, titanium, and aluminum may be included as a residue of an initiator or a catalyst in the process of preparing a conjugated diene polymer solution, or may be a raw material or a conjugate. It may be contained as an impurity such as a solvent used in the process of preparing the diene polymer solution. The initiator and catalyst will be described later.

  The solvent used in the conjugated diene polymer solution is not particularly limited as long as it is inert to the polymerization initiator. For example, a chain hydrocarbon solvent, a cyclic hydrocarbon solvent, Or a mixture of these is used. The chain hydrocarbon solvent is not particularly limited. For example, n-butane, isobutane, 1-butene, isobutylene, trans-2-butene, cis-2-butene, 1-pentene, trans-2-pentene, cis Examples thereof include linear alkanes and alkenes having 4 to 6 hydrocarbons such as 2-pentene, n-pentene, isopentane, neo-pentane, and n-hexane. In addition, the cyclic hydrocarbon solvent is not particularly limited, and examples thereof include aromatic compounds such as benzene, toluene and xylene; and alicyclic hydrocarbon compounds such as cyclopentane and cyclohexane. These solvents may be used alone or in combination of two or more. Among these, n-hexane, cyclohexane, or a mixture thereof is preferably used.

  Although the density | concentration of the conjugated diene polymer in a conjugated diene polymer solution is not specifically limited, Preferably it is 5-60 mass%, More preferably, it is 10-50 mass%.

(Conjugated diene polymer)
The conjugated diene polymer is not particularly limited as long as it is obtained by polymerization, and specifically, a conjugated diene homopolymer or a conjugated diene monomer having a weight average molecular weight of 500 to 1,000,000. And random, tapered or block copolymers of vinyl aromatic monomers. Moreover, the polymer which hydrogenated with respect to the unsaturated double bond of these conjugated diene units can also be used. In this embodiment, the metal residue used for the polymerization and the metal residue used for the hydrogenation reaction can be efficiently removed.

  A weight average molecular weight can be calculated | required by polystyrene conversion using a gel permeation chromatography (GPC).

  The conjugated diene monomer that can be used is not particularly limited, and specifically, 1,3-butadiene, isoprene, piperylene, phenylbutadiene, 3,4-dimethyl-1,3-hexadiene, 4,5-diethyl. Conjugated diene compounds containing 4 to 12 carbon atoms such as -1,3-octadiene can be used, and among these, it is preferable to use 1,3-butadiene and isoprene.

  The vinyl aromatic monomer copolymerizable with the conjugated diene monomer is not particularly limited. Specifically, styrene, α-methylstyrene, styrene substituted with an alkoxy group, 2-vinylpyridine, Vinyl allyl compounds such as 4-vinylpyridine, vinylnaphthalene and vinylnaphthalene substituted with an alkyl group can be used, and among these, styrene and α-methylstyrene are preferably used.

  At this time, when a copolymer is produced by mixing a conjugated diene monomer and a vinyl aromatic monomer, the mass ratio of the conjugated diene monomer to the vinyl aromatic monomer (conjugated diene monomer) The monomer: vinyl aromatic monomer) is not particularly limited, but is preferably 5:95 to 95: 5. When the amount of the conjugated diene monomer used is 5% by mass or more, the impact resistance is good and it tends to be usable for various applications. Moreover, it exists in the tendency for product workability to become favorable because the usage-amount of a conjugated diene monomer is 95 mass ratio or less. Therefore, it is preferable to maintain the said range.

  Such a conjugated diene polymer can be obtained, for example, by performing anionic polymerization using an organolithium compound as an initiator in the present embodiment. Although it does not restrict | limit especially as an organic lithium compound, Specifically, n-butyl lithium, s-butyl lithium, etc. are mentioned. The amount of the initiator used can be set to an amount generally used in this field, and can be freely adjusted according to the molecular weight of the target polymer. Here, when an organic lithium compound is used as an initiator, lithium may be contained in the conjugated diene polymer solution as a metal residue.

  As a polymerization method of the conjugated diene polymer, anionic polymerization is preferable, and living anionic polymerization is more preferable.

(Hydrogenation reaction)
Thereafter, a hydrogenated conjugated diene polymer can be produced by performing a hydrogenation reaction on the obtained polymer solution.

  The hydrogenation (hydrogenation) catalyst used in the hydrogenation is not particularly limited, and conventionally known catalysts, for example, (1) metals such as Ni, Pt, Pd, and Ru are mixed with carbon, silica, alumina, diatomaceous earth. A supported heterogeneous hydrogenation catalyst supported on soil or the like, (2) a so-called organic acid salt such as Ni, Co, Fe, Cr or a transition metal salt such as acetylacetone salt and a reducing agent such as organoaluminum Ziegler type hydrogenation catalysts, (3) homogeneous hydrogenation catalysts such as so-called organometallic complexes, such as organometallic compounds such as Ti, Ru, Rh, Zr, and the like.

  Specifically, JP-B-42-8704, JP-B-43-6636, JP-B-63-4841, JP-B-1-37970, JP-B-1-53851, JP-B-2-9041 Can be applied.

  Preferable examples of the hydrogenation catalyst include a mixture of a titanium compound and a reducing organometallic compound.

  The titanium compound used in the hydrogenation reaction is not particularly limited as long as it is generally used in this field. For example, compounds described in JP-A-8-109219 can be used, and (substitution) Examples thereof include compounds having at least one ligand having a cyclopentadienyl skeleton, an indenyl skeleton, or a fluorenyl skeleton.

  Although it does not specifically limit as what has a cyclopentadienyl skeleton, Specifically, it is a cyclopentadienyl titanium compound, for example, a cyclopentadienyl titanium halide, a cyclopentadienyl (alkoxy) titanium dihalide, Bis (cyclopentadienyl) titanium dihalide, bis (cyclopentadienyl) titanium dialkylated product, bis (cyclopentadienyl) titanium diallylized compound and bis (cyclopentadienyl) dialkoxy compound, alone or Can be used as a mixture.

  The amount of the titanium compound used is preferably 0.01 to 20 mmol, more preferably 0.05 to 5 mmol, per 100 g of the conjugated diene polymer. When the amount of the titanium compound used as the catalyst is 0.01 mmol or more, the hydrogenation reaction proceeds efficiently and the productivity tends to be excellent. Moreover, since it is 20 mmol or less, it becomes a sufficient catalyst compounding quantity and it is economical, and it tends to be suppressed from using an excessive amount of chemical substances for removing the catalyst after the reaction. Therefore, it is preferable to maintain the said range.

  The reducing organometallic compound that can be used together with the titanium compound is not particularly limited as long as it is a reducing agent generally used in this field, and specifically, organoaluminum compounds such as alkylaluminum compounds, alkyls. Examples thereof include organic magnesium compounds such as magnesium compounds, organic alkali metal compounds such as organic lithium compounds, metal hydrides, organic boron compounds, and organic zinc compounds. These compounds can be used alone or in combination.

  Although it does not specifically limit as a hydrogenation reaction using the said titanium-type catalyst, Specifically, international patent application 00/08069, US Patent 4,501,857, 4,673,714, 4,980,421, 5,753,778, 5,910,566, 6,020,439 and the like.

  The hydrogenation reaction can be carried out in an inert solvent. Here, the inert solvent means a solvent that does not react with any reactant in the polymerization reaction or the hydrogenation reaction. Such an inert solvent is not particularly limited, and specific examples thereof include aliphatic hydrocarbons such as n-pentane, n-hexane, n-heptane, and n-octane; cyclopentane, cyclohexane, and cycloheptane. Examples thereof include alicyclic hydrocarbons such as; and ethers such as diethyl ether and tetrahydrofuran, which can be selected from these alone or in combination.

  Although the density | concentration of a conjugated diene polymer is not restrict | limited in particular, Preferably it is 5-50 mass% with respect to the total amount of a conjugated diene polymer solution, More preferably, it is 10-30 mass%. When the polymer concentration is within the above range, it can be adjusted to a polymer solution viscosity that is easy to handle and the productivity is improved, which is preferable.

On the other hand, in the hydrogenation reaction, after the polymer solution is maintained at a constant temperature in an inert gas atmosphere such as hydrogen, helium, argon, or nitrogen, a hydrogenation catalyst is added in a stirred or unstirred state, and hydrogen gas is added. It is preferable to carry out by injecting at a constant pressure. Furthermore, the temperature of the hydrogenation reaction is preferably 30 to 150 ° C., and the pressure is preferably ^{2 to} 30 kg / cm ² .

When the temperature is 30 ° C. or higher, the reactivity is high and a sufficient reaction yield tends to be obtained. Moreover, it exists in the tendency for the side reaction by the heat aging of a polymer to be suppressed because it is 150 degrees C or less. Furthermore, when the pressure is 2 kg / cm ² or more, the reaction rate tends to be high and the reaction time tends to be short. Furthermore, when it is 30 kg / cm ² or less, the cost of investing in the reactor is suppressed, which is preferable from the viewpoint of economy. Therefore, it is preferable to maintain the range.

  By the hydrogenation catalyst as described above, a conjugated diene polymer having a weight average molecular weight of 500 to 1,000,000, or a random, tapered or block copolymer of a conjugated diene monomer and a vinyl aromatic monomer. Hydrogenation is possible selectively with respect to the unsaturated double bond of the conjugated diene unit.

  The metal-containing catalyst used in the hydrogenation reaction step becomes a metal residue that can be contained in the conjugated diene polymer solution.

[Step 2]
In the method for purifying a polymer solution of the present embodiment, step 2 includes at least a conjugated diene polymer solution obtained in step 1 selected from the group consisting of a surfactant (a), sulfuric acid, hydrochloric acid, and nitric acid. In this step, a kind of inorganic acid (b) and polar liquid (c) are added and mixed to obtain a mixed solution.

  Step 2 is a step of obtaining a first mixed liquid by mixing the conjugated diene polymer solution and the surfactant (a) in order to more efficiently transfer the metal residue in the polymer solution to the polar liquid. 2-1 is mixed with the first mixed solution and the inorganic acid (b) to obtain the second mixed solution, 2-2, the second mixed solution and the polar liquid (c) are mixed, It is preferable to have Step 2-3 for obtaining a mixed solution in order. By adopting such an order, the deashing efficiency is improved and the turbidity tends to be improved.

(Step 2-1)
Step 2-1 is a step of mixing the conjugated diene polymer solution and the surfactant (a) to obtain a first mixed solution. By adding the surfactant (a), the mixing of the polymer solution with the inorganic acid and polar liquid described later is promoted, and the removal of the metal residue in the polymer solution becomes easy.

  Although it does not restrict | limit especially as surfactant (a), A cationic surfactant, anionic surfactant, an amphoteric surfactant, a nonionic surfactant is mentioned, These surfactants are used by 1 type. Or may be used in plural. Among these, from the viewpoint of improving the deashing efficiency and turbidity, it is more preferable that at least a nonionic surfactant is included because it is hardly affected by the electrolyte and can be used in combination with other surfactants.

  Although it does not restrict | limit especially as a nonionic surfactant, Specifically, polyvinyl alcohol, polyoxypropylene polyoxyethylene alkyl ether, polyoxyethylene lauryl ether, polyoxyethylene alkyl ether, polyoxyethylene polyoxypropylene ether Derivatives, polyethylene glycol, methoxy polyethylene glycol, polyoxyethylene phenyl ether, sorbitan fatty acid ester, polyoxyethylene fatty acid ester, polyoxyethylene alkylamine, polyoxyethylene sorbitan fatty acid ester, polyoxyethylene glycerol borate fatty acid ester, polyoxyethylene alkyl Ester, fatty acid alkanolamide, polyoxyethylene fatty acid alkanolamide, cellulose Conductor, and the like. Of these, polyoxypropylene polyoxyethylene alkyl ether and polyoxyethylene alkylamine are particularly preferably used.

  Further, surfactants other than nonionic surfactants include anionic surfactants such as sodium laurate, sodium dodecylbenzenesulfonate, sodium dialkylsulfosuccinate, sodium alkyldiphenyl ether disulfonate, sodium polyoxyethylene lauryl ether sulfate, etc. ; Cationic surfactants such as stearylamine acetate and alkylamine salts; amphoteric surfactants such as laurylcarboxylhydroxylethyl and laurylbetaine.

  Moreover, the addition amount of the surfactant is not particularly limited, but 0.001% by mass to 10% by mass is preferably added relative to the mass of the polymer in the polymer solution, and 0.001% by mass to 5%. It is more preferable to add by mass%, and it is more preferable to add 0.01 mass% to 1 mass% by mass. The blending amount is preferably 0.001% by mass or more from the viewpoint of easy removal of metal residues. Moreover, when the addition amount is 10% by mass or less, it is preferable from the viewpoint of preventing causes such as contamination of foreign substances in the product.

(Process 2-2)
Step 2-2 is a step of mixing the first mixed solution and the inorganic acid (b) to obtain a second mixed solution. By adding the inorganic acid (b), the metal residue in the polymer solution is easily dissolved in the polar liquid (c), and the removal of the metal residue in the polymer solution is facilitated.

  The inorganic acid (b) is at least one selected from the group consisting of sulfuric acid, hydrochloric acid, and nitric acid, and may be one type or plural types. Among these, it is preferable that sulfuric acid is contained as the inorganic acid (b) from the viewpoints of burden on the wastewater treatment facility, corrosivity, ease of removal of metal residues, and colorability.

  The amount of the inorganic acid (b) added is not particularly limited, but is preferably 1 to 100 times, more preferably 2 to 50 times the weight of the metal residue in the polymer solution. It is preferable from the viewpoint of ease of metal residue removal that the addition amount is 1 or more times. Moreover, it is preferable from a viewpoint of wastewater treatment because the addition amount is 100 times or less.

  From the viewpoint that the metal residue in the polymer solution is easily dissolved by the polar liquid (c), the metal (metal residue) is soluble in the polar liquid (c) in the second mixed liquid after Step 2-2. It is preferable that it is in a state. In particular, in Step 1, when the conjugated diene polymer solution contains titanium, after Step 2-2, titanium becomes soluble in the polar liquid (c) in the second mixed solution. Preferably it is. The “soluble state” is not particularly limited, and examples thereof include a state in which a metal forms a salt with an inorganic acid.

(Step 2-3)
Step 2-3 is a step of mixing the second liquid mixture and the polar liquid (c) to obtain a liquid mixture. The metal residue in the polymer solution can be transferred to the polar liquid by adding the polar liquid (c).

  Although it does not restrict | limit especially as a polar liquid (c), Specifically, water, methanol, ethanol, propanol, and isopropanol are mentioned, It uses preferably. Among these, water is preferable from the viewpoint of burden on the waste liquid treatment facility and ease of handling.

  The amount of the polar liquid (c) added is not particularly limited, but is preferably 0.5 to 10 times by volume, more preferably 0.2 to 5.0 times by volume with respect to the total amount of the polymer solution. is there. The addition amount of the polar liquid (c) is preferably 0.5 or more by volume ratio from the viewpoint of easy removal of the metal residue. Moreover, it is preferable from the surface of productivity because it is 10 times or less by volume ratio.

  In step 2-3, when alcohol is used as the polar liquid (c), the alcohol concentration in the mixed solution in step 2 is preferably 2000 ppm or less, more preferably 1000 ppm or less from the viewpoint of the burden on the waste liquid treatment facility. .

(Addition method)
The order of addition of the surfactant (a), the inorganic acid (b), and the polar liquid (c) is not particularly limited, but from the viewpoint of metal residue removal efficiency, the surfactant is added to the polymer solution. Afterwards, it is preferable to add the inorganic acid and finally add the polar liquid. Addition may be performed while mixing, or may be performed after addition.

(Mixing method)
The mixing method of the conjugated diene polymer solution, the surfactant (a), the inorganic acid (b), and the polar liquid (c) in this embodiment is not particularly limited, but a method of mixing in a container equipped with a stirring blade is possible. Can be mentioned. The shape of the stirring blade is not particularly limited, and any blade such as a screw blade, a propeller blade, an anchor blade, a paddle blade, a pitched paddle blade, a turbine blade, and a large lattice blade can be used.

  In order to sufficiently bring the metal residue in the conjugated diene polymer solution into contact with the surfactant, the inorganic acid, and the polar liquid, a mixing method capable of giving a large shearing force, collision force, and frictional force is preferable. Specific devices for applying the shearing force include a stirrer, a homogenizer including an emulsifier, a pump, and the like. Specific devices for applying a collision force or a friction force include a ball mill or a rod mill or a high-pressure grinding roll.

Among them, using a rotary disperser having a meshing structure as disclosed in JP-A-6-136034, P / V value ≧ 3 × 10 ⁴ (kw / m ³ ), peripheral speed (2πr · n) ≧ 5 (m / s) It is preferable to perform mixing under the conditions of Thereby, strong shear can be given. Here, P (kw) is the power of the disperser, and can be easily obtained by measuring the power consumption during mixing. V (m ³ ) is the volume of the mixing part, and is the spatial volume of the part that gives a shearing force to the solution. Further, r (m) is the radius of the rotor outermost tooth, and n (s ⁻¹ ) is the rotation speed of the rotor.

The P / V value is preferably 3 × 10 ⁴ (kw / m ³ ) or more, more preferably 5 × 10 ⁴ (kw / m ³ ) or more, and even more preferably 1 × 10 ⁵ (kw). / M ³ ) or more. The upper limit of the P / V value is not particularly limited, but is preferably 1 × 10 ⁹ (kw / m ³ ) or less. When the P / V value is 3 × 10 ⁴ (kw / m ³ ) or more, the catalyst residue is sufficiently transferred to the polar liquid, and the removal efficiency of the catalyst residue in the downstream process tends to be improved.

  The peripheral speed (2πr · n) is preferably 5 (m / s) or more, more preferably 10 (m / s) or more, and further preferably 20 (m / s) or more. The upper limit of the peripheral speed (2πr · n) is not particularly limited, but is preferably 1000 (m / s) or less. When the peripheral speed is 5 (m / s) or more, the catalyst residue is sufficiently transferred to the polar liquid, and the removal efficiency of the catalyst residue in the downstream process tends to be improved.

Furthermore, when the P / V value is 3 × 10 ⁴ (kw / m ³ ) or more and the peripheral speed is 5 (m / s) or more, the catalyst residue is sufficiently transferred to the polar liquid, and in the downstream process. The removal efficiency of the catalyst residue tends to be further improved.

In particular, from the viewpoint of mixing efficiency, in Step 2-3, using a rotary disperser having a meshing structure, P / V value ≧ 3 × 10 ⁴ (kw / m ³ ), peripheral speed (2πr · n) ≧ 5 It is preferable to perform the mixing under the condition (m / s).

[Step 3]
In the present embodiment, Step 3 is a step of removing the surfactant (a), the inorganic acid (b), and the polar liquid (c) from the mixed solution. Due to the effects of the surfactant (a) and inorganic acid (b) added in Step 2, the metal residue contained in the polymer solution is dissolved in the polar liquid and is easily removed. Therefore, the metal residue is removed from the polymer solution by removing the surfactant (a), the inorganic acid (b), and the polar liquid (c).

  The method for removing the surfactant (a), the inorganic acid (b), and the polar liquid (c) is not particularly limited as long as it is a method generally used in this field. For example, stationary separation, centrifugation It can be easily removed by a physical method such as separation.

  In particular, it is possible to efficiently remove metal residues by mixing a conjugated diene polymer solution, a surfactant, an inorganic acid, and a polar liquid, and then applying centrifugal acceleration to the mixed polymer solution. is there. If possible, the polar liquid may be removed by stationary separation before applying the centrifugal acceleration. The method for imparting centrifugal acceleration is not particularly limited, and may be a batch type or a continuous type. Of these, the continuous type is preferred for industrial removal of catalyst residues. Although it does not specifically limit as a continuous apparatus, There exist centrifuges, such as a decanter type and a disk type. Among these, from the viewpoint of the removal efficiency of the metal residue, surfactant (a), inorganic acid (b), and polar liquid (c), a relative acceleration of 100 G or more is obtained with respect to the mixed solution using a centrifuge. It is preferable to remove the surfactant (a), the inorganic acid (b), and the polar liquid (c) from the mixed solution.

  From the viewpoint of productivity and ease of installation due to small size, the centrifuge is preferably a disk-type centrifuge, and examples of the disk-type centrifuge include those manufactured by Alfa Laval and Westphalia Apparatus. By applying a relative acceleration of 100 G or more using such an apparatus, the catalyst residue removal efficiency tends to be improved.

The relative centrifugal acceleration (RCF) can be obtained from the following general formula.
RCF = 1118 × r × N ² × 10 ⁻⁸ (G)
r: turning radius (cm)
N: Number of revolutions per minute (rpm)

  In this embodiment, the higher the relative centrifugal acceleration, the higher the catalyst residue removal efficiency. Therefore, the relative centrifugal acceleration is preferably 500 G or more, more preferably 3000 G or more, and further preferably 4000 G or more. The upper limit of the relative centrifugal acceleration is not particularly limited, but is preferably 50000G or less.

(Polymer solution after step 3)
The polymer solution obtained through the steps 1 to 3 as described above has less metal residue than the polymer solution in the step 1. Therefore, it can be a polymer solution having excellent transparency and good hue.

  Hereinafter, the present invention will be described in detail with reference to specific examples and comparative examples, but the present invention is not limited to the following examples. In the following examples and comparative examples, the properties and physical properties of the polymers were measured by the following methods.

[(1): Preparation of block copolymer]
[Polymerization Example 1]
Polystyrene-polybutadiene-polystyrene block copolymer (styrene content: 20.0 mass%) by a conventionally known sequential living anionic polymerization method using n-butyllithium as an initiator in a mixed solvent of cyclohexane and n-hexane. Butadiene content: 80.0% by mass, weight average molecular weight: 90,000). The concentration of the polystyrene-polybutadiene-polystyrene block copolymer in the resulting conjugated diene polymer solution was 22% by mass.

[Production Example 1]
The conjugated diene polymer solution obtained in Polymerization Example 1 was hydrogenated at a temperature of 85 ° C. using di-p-trisbis (1-cyclopentadiphenyl) titanium and n-butyllithium as a hydrogenation catalyst. A polymer solution 1 was obtained. The concentration of the polymer in the conjugated diene polymer solution 1 was 22% by mass. The solvent of the conjugated diene polymer solution 1 was removed by heating and analyzed by NMR (manufactured by JEOL Ltd., apparatus name: JNM-ECS400), and as a result, hydrogenation of 95% or more of double bonds in the polybutadiene block was confirmed. did. The amount of metal contained in the obtained polymer was confirmed by elemental analysis using inductively coupled plasma (ICP, Inductively coupled plasma, manufactured by Shimadzu Corporation, apparatus name: ICPS-7510). The measurement results are shown in Table 1.

[Production Example 2]
The conjugated diene polymer solution obtained in Polymerization Example 1 was hydrogenated at a temperature of 95 ° C. using bis (cyclopentadienyl) titanium dichloride and triethylaluminum as a hydrogenation catalyst, and a conjugated diene polymer solution 2 was obtained. Obtained. The concentration of the polymer in the conjugated diene polymer solution 2 was 22% by mass. As a result of removing the solvent of the conjugated diene polymer solution 2 by heating and analyzing by NMR (manufactured by JEOL Ltd., apparatus name: JNM-ECS400), hydrogenation of 95% or more of double bonds in the polybutadiene block was confirmed. did. The amount of metal contained in the obtained polymer was confirmed by elemental analysis using inductively coupled plasma (ICP, Inductively coupled plasma, manufactured by Shimadzu Corporation, apparatus name: ICPS-7510). The measurement results are shown in Table 1.

[(2): Method for specifying structure of copolymer and method for evaluating quality]
[(2-1): Measurement of styrene content of block copolymer]
Using the chloroform solution of the block copolymer obtained in the above production example, the styrene content was measured by an ultraviolet spectrophotometer (UV-2450, manufactured by Shimadzu Corporation).

[(2-2): Measurement of molecular weight of block copolymer]
The weight average molecular weight (polystyrene conversion) of the block copolymer was measured by GPC (HLC-8220 manufactured by Tosoh Corporation) using the tetrahydrofuran (THF) solution of the block copolymer obtained in the above production example.

[(2-3): Measurement of hydrogenation rate]
The hydrogenation rate of the double bond in the block copolymer obtained in the above production example was measured by NMR (manufactured by JEOL Ltd., apparatus name: JNM-ECS400).

[(2-4): Measurement of metal residue amount]
The amount of metal residue contained in the block copolymer obtained in the above production example, and the amount of metal residue contained in the polymer obtained in Examples and Comparative Examples described below were determined by inductively coupled plasma ((ICP, It was measured by elemental analysis using Inductive Coupled Plasma (manufactured by Shimadzu Corporation, apparatus name: ICPS-7510).

[(2-4): Measurement of color tone]
The block copolymers obtained in Examples and Comparative Examples described later were roll-kneaded at 180 ° C., and then formed into a 2 mm sheet by hot pressing at 200 ° C. The b * value was measured from a colorimeter (NDJ-400-2 manufactured by Nippon Denshoku Co., Ltd.) using this test piece. The b ^* value has a value of −60 to 60, −60 indicates blue, and 60 indicates yellow. Based on the obtained value, the color tone was evaluated according to the following criteria. Evaluation shall be (circle), (triangle | delta), and x from a favorable order.
b ^* ≦ 2: ○
2 <b ^* ≦ 5: Δ
5 <b ^* : x

[(2-5): Measurement of turbidity]
The haze of the polymer (Nippon Denshoku Co., Ltd. 1001DP) was measured from a turbidimeter using the 2 mm sheet. The haze is a value representing turbidity, and the turbidity (H) = D / T ×, based on the total transmittance T irradiated through the lamp and transmitted through the sample and the transmittance D of light diffused and scattered in the sample. 100 is required. Based on the obtained value, haze (H) was evaluated according to the following criteria. Evaluation shall be (circle), (triangle | delta), and x from a favorable order.
H ≦ 6.0: ○
6.0 <H ≦ 12: Δ
12 <H: ×

[Example 1]
Pegnol L4 (manufactured by Toho Chemical Industry Co., Ltd.) corresponding to 0.5% by mass with respect to the mass of the polymer in the conjugated diene polymer solution 1 obtained in Production Example 1; 3.5 times as much sulfuric acid as the mass of the metal residue in the conjugated diene polymer solution and 2.0 times as much water as that of the conjugated diene polymer solution are added in order to have a meshing structure. 6 × 10 ⁻⁴ minutes (3.6 × 10 ⁻² seconds) at 60 ° C. and power P: 1 kW using a rotary disperser (Cabitron 1010 manufactured by Nikko Kogyo Co., Ltd., volume V: 4 × 10 ⁻⁶ m ³ ) Mixing was performed to obtain a mixed solution. Centrifugal acceleration was applied to the obtained mixed solution for 1 second with a centrifuge (a disk type centrifuge manufactured by Alfa Laval, relative centrifugal acceleration 100G). The centrifuged mixture was sent to a tank heated to 60 ° C. and allowed to stand to separate into a conjugated diene polymer solution phase and an aqueous phase. The separation state was good.

  The aqueous phase was removed from the mixture to obtain a conjugated diene polymer solution. Irganox 1076 (manufactured by Ciba Specialty Chemicals) corresponding to 1% by mass of the polymer in the conjugated diene polymer solution was added and mixed, followed by vacuum drying to obtain a solid polymer. The above various measurements were performed on the resulting conjugated diene polymer solution and solid polymer. Table 3 shows the measurement results.

[Examples 2-5, Comparative Examples 2-3]
A conjugated diene polymer solution was obtained in the same manner as in Example 1 except that the conjugated diene polymer solution, the surfactant, the type of acid, and the amount added were changed. Table 2 shows the types of conjugated diene polymer solution, surfactant, and inorganic acid used at this time. Further, Irganox 1076 (manufactured by Ciba Specialty Chemicals) corresponding to 1% by mass of the polymer in the obtained conjugated diene polymer solution was added and mixed, followed by vacuum drying to obtain a solid polymer. The above various measurements were performed on the resulting conjugated diene polymer solution and solid polymer. Table 3 shows the measurement results.

Example 6
After adding 2.0 times volume water of the conjugated diene polymer solution 1 to the conjugated diene polymer solution 1 obtained in Production Example 1, the mass of the polymer in the conjugated diene polymer solution is increased. Pegnol L4 (manufactured by Toho Chemical Co., Ltd.) corresponding to 0.5% by mass and 3.5 times as much sulfuric acid as the mass of the metal residue in the conjugated diene polymer solution 1 were simultaneously added, It is 6 × 10 ⁻⁴ minutes (3.6 ×) at 60 ° C. and power P: 1 kW by a rotary disperser having a meshing structure (Cabitron 1010 manufactured by Nikko Corporation, mixing unit volume V: 4 × 10 ⁻⁶ m ³ ). ^10-2 seconds) to obtain a mixed solution. Centrifugal acceleration was applied to the obtained mixed solution for 1 second with a centrifuge (a disk type centrifuge manufactured by Alfa Laval, relative centrifugal acceleration 100G). The centrifuged mixture was sent to a tank heated to 60 ° C. and allowed to stand to separate into a conjugated diene polymer solution phase and an aqueous phase. The separation state was good.

  The aqueous phase was removed from the mixture to obtain a conjugated diene polymer solution. Irganox 1076 (manufactured by Ciba Specialty Chemicals) corresponding to 1% by mass of the polymer in the conjugated diene polymer solution was added and mixed, followed by vacuum drying to obtain a solid polymer. The above various measurements were performed on the resulting conjugated diene polymer solution and solid polymer. Table 3 shows the measurement results.

[Comparative Example 1]
A rotary disperser having a meshing structure (Cabitron 1010 manufactured by Nikko Kogyo Co., Ltd.) is added to the conjugated diene polymer solution 1 obtained in Production Example 1 in an amount 2.0 times that of the conjugated diene polymer solution 1. The mixture was mixed at 60 ° C. and power P: 1 kW for 6 × 10 ⁻⁴ minutes (3.6 × 10 ⁻² seconds) according to the mixing unit volume V: 4 × 10 ⁻⁶ m ³ ). The mixed solution was sent to a tank heated to 60 ° C. and allowed to stand to separate into a conjugated diene polymer solution phase and an aqueous phase. The separation state was good.

  The aqueous phase was removed from the mixture to obtain a conjugated diene polymer solution. Irganox 1076 (manufactured by Ciba Specialty Chemicals) corresponding to 1% by mass of the polymer in the conjugated diene polymer solution was added and mixed, followed by vacuum drying to obtain a solid polymer. The above various measurements were performed on the resulting conjugated diene polymer solution and solid polymer. Table 3 shows the measurement results.

*-: Not used * "Sorbon T-80" (manufactured by Toho Chemical Co., Ltd.)
* "Softamin LD" (manufactured by Toho Chemical Industry Co., Ltd.)

  The method for polymerizing a conjugated diene polymer of the present invention has industrial applicability as a method for removing a metal residue remaining in a conjugated diene polymer solution.

Claims (10)

Preparing a conjugated diene polymer solution comprising at least one metal selected from the group consisting of lithium, titanium, and aluminum, and a conjugated diene polymer;
To the conjugated diene polymer solution, at least one inorganic acid (b) selected from the group consisting of surfactant (a), sulfuric acid, hydrochloric acid and nitric acid, and polar liquid (c) are added, mixed and mixed. Step 2 for obtaining a liquid;
Removing the surfactant (a), the inorganic acid (b), and the polar liquid (c) from the mixed solution, and
Wherein the surfactant (a) is seen containing a nonionic surfactant,
Step 2 is
Step 2-1 for mixing the conjugated diene polymer solution and the surfactant (a) to obtain a first mixed solution;
Step 2-2 for mixing the first mixed solution and the inorganic acid (b) to obtain a second mixed solution;
Step 2-3 of mixing the second liquid mixture and the polar liquid (c) to obtain the liquid mixture;
In order,
A method for producing a conjugated diene polymer. In the step 1, the conjugated diene polymer solution containing the lithium and / or the titanium, method for producing a conjugated diene polymer according to claim 1. After the step 2-2, the metal is in a soluble state in the polar liquid (c) in the second liquid mixture.
The manufacturing method of the conjugated diene polymer of Claim 1 or 2 . In the step 1, the conjugated diene polymer solution contains the titanium,
After the step 2-2, in the second mixed liquid, the titanium is in a soluble state in the polar liquid (c).
The manufacturing method of the conjugated diene polymer as described in any one of Claims 1-3 . The inorganic acid (b) contains sulfuric acid,
The manufacturing method of the conjugated diene polymer as described in any one of Claims 1-4 . The polar liquid (c) contains water;
The manufacturing method of the conjugated diene polymer as described in any one of Claims 1-5 . In the step 2-3, mixing is performed under the following conditions using a rotary disperser having a meshing structure.
The manufacturing method of the conjugated diene polymer as described in any one of Claims 1-6 .
P / V value ≧ 3 × 10 ⁴
(P: Disperser power (kw), V: Volume of mixing section (m ³ ))
Peripheral speed (2πr · n) ≧ 5
(R: radius of rotor outermost teeth (m), n: number of rotations of rotor (s ⁻¹ ) In the step 3, by applying a relative acceleration of 100 G or more to the mixed solution using a centrifuge, the surfactant (a), the inorganic acid (b), and the polar liquid ( The method for producing a conjugated diene polymer according to any one of claims 1 to 7 , wherein c) is removed. The method for producing a conjugated diene polymer according to claim 8 , wherein the centrifuge is a disk-type centrifuge. Wherein in the step 2, the alcohol concentration in the mixture is 2000ppm or less, it claims 1-9 or method for producing a conjugated diene polymer according to one of.