JP3959630B2 - Method for producing high cis polybutadiene - Google Patents

Description

【００８２】
表１から以下のようなことがわかる。
高シスポリブタジエンの重合溶液に、老化防止剤を添加した後に重合停止剤を添加して得られる比較例１の高シスポリブタジエンは、アルミニウム金属含有量が少ないものの、色調に劣る。
工程（Ｃ）で添加した水を系外へ排出せずに得られる比較例２の高シスポリブタジエンは、色調は良好であるが、アルミニウム金属含有量が多い。
酸性条件下でスチームストリッピングする比較例３の方法では、金属を腐食しやすいクラムが得られ、スチームストリッピング工程以降での設備の腐食を促進しやすい。
【００８３】
上記の比較例に比べ、本発明で規定する方法で得られる実施例１〜３の高シスポリブタジエンは、アルミニウム金属含有量が少なく、色調も良好であり、金属を腐食し難いクラムが得られている。
【発明の効果】
本発明によれば、スチームストリッピングの工程以降での製造設備の腐蝕を抑制しながら、アルミニウム金属含有量が低減され、色相に優れる高シスポリブタジエンの製造方法が提供される。[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing high cis polybutadiene, and relates to a method for producing high cis polybutadiene having a reduced aluminum metal content and excellent hue while suppressing corrosion of production equipment after the steam stripping step.
[0002]
[Prior art]
High cis polybutadiene is widely used as a rubber material for tires or impact-resistant polystyrene. This polymer is usually produced by solution polymerization of 1,3-butadiene using a polymerization catalyst consisting of an organoaluminum compound, a transition metal compound and water, separating the solvent by a steam stripping method, and drying. Yes.
[0003]
However, in such a conventional production method, a substance derived from the polymerization catalyst remains in the high cis polybutadiene and affects various polymer characteristics. For example, when high cis polybutadiene having a high aluminum metal content derived from an organoaluminum compound is used as a rubber material for impact-resistant polystyrene, it may cause foreign matters in the impact-resistant polystyrene. Of the organoaluminum compounds, organoaluminum halides are used because of their high polymerization activity. However, when high cispolybutadiene is produced using a polymerization catalyst containing organoaluminum halides, the equipment after the steam stripping process is particularly preferred. Have problems such as causing corrosion.
[0004]
In order to reduce the metal content of the rubber-like polymer, an improvement in a method for recovering the rubber-like polymer from a polymerization solution containing the rubber-like polymer has been proposed.
For example, Japanese Patent Publication No. 4-54684 discloses (1) a step of adding a specific ester compound as a polymerization terminator to a polymerization solution of a rubber-like polymer, (2) adding a specific amount of water to emulsify, Further disclosed is a method for recovering a rubbery polymer comprising a step of phase inversion by adding a specific amount of water, and (3) a step of allowing the phase change product to stand and steam stripping the separated rubbery polymer solution. Has been. However, according to such a method, although a rubber-like polymer having a low aluminum metal content can be obtained, the obtained rubber-like polymer has a poor hue, and its commercial value is remarkably reduced, or a steam stripping step. It may not be possible to suppress the corrosion of the equipment thereafter.
[0005]
Japanese Patent Laid-Open No. 10-168101 discloses that (1) a phosphon is added to a solution of a rubbery polymer for the purpose of efficiently removing a catalyst residue and obtaining a rubbery polymer having good transparency and heat and moisture resistance. A step of adding an acid, water and a phosphate ester, (2) a step of adding an antioxidant, (3) a step of adding water if desired, and (4) a step of steam stripping in a specific temperature range. A method for recovering a rubbery polymer is disclosed. According to such a method, although a rubbery polymer having a good hue can be obtained, the effect of reducing the aluminum metal content is insufficient, or the corrosion of equipment after the steam stripping step cannot be suppressed. To do.
[0006]
[Problems to be solved by the invention]
In view of the above circumstances, an object of the present invention is to provide a method for producing high cis polybutadiene having a reduced aluminum metal content and excellent hue while suppressing corrosion of production equipment after the steam stripping step. It is in.
[0007]
[Means for Solving the Problems]
In the production of high cis polybutadiene, the present inventors have made extensive studies on the polymer recovery method. As a result, after the polymerization of the high cis polybutadiene polymerization solution is stopped, an anti-aging agent is added, and then water is added. The above problem can be achieved by adopting a method of steam stripping a high cis polybutadiene solution obtained by discharging a specific amount of added water out of the system under alkaline conditions. The present invention has been completed based on this finding.
[0008]
Thus, according to the present invention, 1,3-butadiene is polymerized in an inert solvent by using a catalyst consisting essentially of a transition metal compound, an organoaluminum compound, and a compound having active hydrogen to produce high cis polybutadiene. Producing step (A);
Step (B) of adding an anti-aging agent to the resulting high cis polybutadiene solution after stopping the polymerization;
Step (C) of adding 10% by weight or more of the added water out of the system after adding water to the high cis polybutadiene solution obtained in the step (B);
A step (D) of separating the high cis polybutadiene by steam stripping the high cis polybutadiene solution obtained in the step (C) under an alkaline condition;
A process for producing high cis polybutadiene is provided.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the present invention will be described in detail.
The method for producing high cis polybutadiene according to the present invention comprises polymerizing 1,3-butadiene in an inert solvent by using a catalyst consisting essentially of a transition metal compound, an organoaluminum compound, and a compound having active hydrogen. Producing cis polybutadiene (A);
Step (B) of adding an anti-aging agent to the resulting high cis polybutadiene solution after stopping the polymerization;
Step (C) of adding 10% by weight or more of the added water out of the system after adding water to the high cis polybutadiene solution obtained in the step (B);
The step (D) of separating the high cis polybutadiene by steam stripping the high cis polybutadiene solution obtained in the step (C) under an alkaline condition.
[0010]
In step (A), 1,3-butadiene is polymerized in an inert solvent using a catalyst consisting essentially of a transition metal compound, an organoaluminum compound, and a compound having active hydrogen to produce high cis polybutadiene. Let
[0011]
The inert solvent is not particularly limited as long as it dissolves high cis polybutadiene and does not adversely affect the polymerization activity.
Specific examples thereof include aromatic hydrocarbons such as benzene, toluene and xylene; aliphatic hydrocarbons such as n-butane, n-pentane, n-hexane and n-heptane; fats such as cyclohexane, methylcyclohexane and cyclopentane. Cyclic hydrocarbons; olefinic hydrocarbons such as cis-2-butene and trans-2-butene; halogenated hydrocarbons such as methylene chloride and carbon tetrachloride; and the like.
[0012]
These inert solvents can be used alone or in combination of two or more. The amount of the inert solvent used is not particularly limited, but it is used so that the 1,3-butadiene concentration is preferably in the range of 5 to 50% by weight, more preferably 10 to 40% by weight.
[0013]
The transition metal compound is a compound containing an iron group or platinum group element of groups 8 to 10 of the periodic table.
As the transition metal compound, salts and complexes of these elements are preferably used. Of these elements, cobalt and nickel are preferable, and cobalt is particularly preferable.
[0014]
Specific examples of the transition metal compound include, for example, inorganic acid salts such as cobalt chloride, cobalt bromide, and cobalt nitrate; cobalt hexanoate, cobalt octenoate, cobalt stearate, cobalt naphthenate, cobalt acetate, cobalt oxalate, versatic acid Organic acid salts such as cobalt (cobalt salt of aliphatic monocarboxylic acid having 6 to 20 carbon atoms having a carboxyl group on tertiary carbon having three alkyl groups having 1 or more carbon atoms bonded), cobalt malonate; cobalt bisacetyl Organic base complexes such as acetonate, cobalt trisacetylacetonate, ethyl acetoacetate cobalt, cobalt halide triarylphosphine complex, trialkylphosphine complex, pyridine complex and picoline complex; And nickel compounds. These transition metal compounds may be used alone or in combination of two or more.
Among the transition metal compounds, cobalt hexanoate, cobalt octenoate, cobalt stearate, cobalt naphthenate, and nickel compounds corresponding to these are preferable, and cobalt octenoate is particularly preferable.
[0015]
The amount of these transition metal compounds used is preferably 0.0001 to 1 mmol, more preferably 0.0005 to 0.5 mmol, particularly preferably 0.001 per 1 mol of 1,3-butadiene used for the polymerization. It is in the range of ˜0.1 mmol.
[0016]
An organoaluminum compound is a compound in which at least one hydrocarbon group is bonded to an aluminum atom. The hydrocarbon group is not particularly limited, but is preferably an alkyl group, more preferably an alkyl group having 1 to 10 carbon atoms, and particularly preferably an alkyl group having 2 to 4 carbon atoms.
[0017]
Specific examples of the organoaluminum compound include organoaluminum halide compounds such as diethylaluminum monochloride, diethylaluminum monobromide, dibutylaluminum monochloride, dicyclohexylaluminum monochloride, diphenylaluminum monochloride, ethylaluminum sesquichloride and ethylaluminum dichloride. Alkylalkyl compounds such as trimethylaluminum, triethylaluminum, triisopropylaluminum, and triisobutylaluminum; organic aluminum hydride compounds such as diethylaluminum hydride and ethylaluminum sesquihydride. Among these, an organoaluminum halide compound and an alkylaluminum compound are preferable, diethylaluminum monochloride, ethylaluminum sesquichloride, ethylaluminum dichloride, and triisobutylaluminum are more preferable, and diethylaluminum monochloride is particularly preferable. These organoaluminum compounds can be used alone or in combination of two or more.
[0018]
The amount of the organoaluminum compound used is preferably 0.01 to 10 mmol, more preferably 0.1 to 5 mmol, particularly preferably 0.3 to 2 mmol, per mol of 1,3-butadiene used for polymerization. Range.
[0019]
Examples of the compound having active hydrogen include water; lower alcohols such as methanol and ethanol; carboxylic acids such as formic acid, acetic acid and benzoic acid; amine compounds such as ammonia and aniline; and the like. preferable.
The compound having active hydrogen is a component used for stably improving the catalytic activity. The amount used is preferably in the range of 0.1 to 0.8 mole per mole of organoaluminum compound.
[0020]
The method for adding the transition metal compound, the organoaluminum compound and the compound having active hydrogen used as the catalyst component is not particularly limited, and even if it is simultaneously added to an inert solvent or an inert solvent solution of 1,3-butadiene, You may add sequentially. Especially, it is preferable to add each said component sequentially to an inert solvent solution.
When each component is added sequentially, the order of addition is not particularly limited, but it is particularly preferable to add the compound having active hydrogen, the organoaluminum compound, and the transition metal compound in this order. In adding each component, the organoaluminum compound and the transition metal compound are preferably added as a solution having a concentration of 1 to 20% by weight of an inert solvent used for polymerization.
[0021]
As a method of adding each component, a method of adding a compound having active hydrogen to an inert solvent solution of 1,3-butadiene, adding an organoaluminum compound, and then adding a transition metal compound is most preferable.
[0022]
The temperature at which the catalyst component is added is usually in the range of 0 to 100 ° C, preferably 10 to 60 ° C.
[0023]
In the present invention, as the transition metal compound, a mixture obtained by mixing with an organometallic compound of an element selected from Group 1 to 3 elements and Group 11 to 13 elements in an inert solvent and aging in advance is used. May be. As the inert solvent, the same solvent as that used for the polymerization of 1,3-butadiene can be used.
[0024]
The elements of Groups 1 to 3 and Groups 11 to 13 of the periodic table are not particularly limited, but among them, lithium, magnesium, aluminum, and boron are preferable.
Specific examples of organometallic compounds of these elements include, for example, organolithium compounds such as methyllithium, butyllithium, neopentyllithium, benzyllithium, trimethylsilylmethyllithium, and bistrimethylsilylmethyllithium in addition to the organoaluminum compounds described above; And organic magnesium compounds such as dibutylmagnesium and dihexylmagnesium; and organic zinc compounds such as dimethylzinc and diethylzinc. These organometallic compounds can be used alone or in combination of two or more. Of these organometallic compounds, organoaluminum compounds are preferred, trialkylaluminum compounds are more preferred, and triisobutylaluminum is particularly preferred.
[0025]
The mixing ratio of the organometallic compound and the transition metal compound when aging the transition metal compound is preferably 0.05 to 5 mol, more preferably 0. It is used in a range of 1 to 2 mol, particularly preferably 0.2 to 0.9 mol. When mixing both components, it is preferable to mix so that the density | concentration of the transition metal compound in an inert solvent may be 0.1 to 10 weight%, Preferably it is the range of 0.5 to 5 weight%. Aging is usually carried out at 0 to 80 ° C., preferably 10 to 40 ° C., usually for 0.1 to 24 hours, preferably 1 to 20 hours after mixing both components.
[0026]
When adding a compound having active hydrogen to an inert solvent or an inert solvent solution of 1,3-butadiene, it is preferable to add the compound through a porous filter medium because the gelation suppressing effect during polymerization is further improved. .
The material of the filter medium is not particularly limited, and examples thereof include stainless steel, steel, brass, nickel-based heat-resistant alloy, carbon, graphite, alundum, silica, ceramics, and the like. The filter medium is obtained by sintering these materials. is there.
The pore size of the filter medium is preferably 5 microns or less, more preferably 2 microns or less.
[0027]
In the present invention, a gelation inhibitor can be further used as desired.
The gelation inhibitor is not particularly limited as long as it is a compound that can suppress gelation during polymerization of 1,3-butadiene, and specific examples thereof include, for example, dilauryl-3,3-thiodipropionate, Diester compounds of thio-dipropionic acid such as stearyl-3,3-thiodipropionate; 4,4′-thiobis (3-methyl-6-tert-butylphenol), 2,5-di-tert-butyl Phenol compounds such as hydroquinone and 2,5-di-t-amylhydroquinone; phosphate triester compounds such as trimethyl phosphate, triethyl phosphate and triphenyl phosphate; trimethyl phosphite and triethyl phosphite , Tributyl phosphite, triphenyl phosphite, tris (nonylphenyl) phosphite Ester compounds; thiourea compounds such as thiourea, N, N-diethylthiourea, N, N-dibutylthiourea, N, N-diphenylthiourea; n-octyl mercaptan, n-dodecyl mercaptan, t-dodecyl mercaptan, 2- Thiols such as mercaptobenzothiazol; ortho ester compounds such as trimethyl orthoformate, triethyl orthoformate, trimethyl orthoacetate, triethyl orthoacetate, trimethyl orthobutyrate, triethyl orthobutyrate; dimethyl phenylphosphonate, phenylphosphonic acid And phenylphosphonic acid diester compounds such as diethyl.
[0028]
Among these, orthoester compounds and phenylphosphonic acid diester compounds are preferable, and trimethyl orthoformate and dimethyl phenylphosphonate are more preferable. These gelation inhibitors can be used alone or in combination of two or more.
The amount of the gelation inhibitor used is preferably in the range of 0.002 to 0.06 mmol per mole of 1,3-butadiene used for the polymerization.
[0029]
In the present invention, a molecular weight regulator generally used in a method for producing a high cis polybutadiene can be used as necessary.
Specific examples of molecular weight regulators include, for example, α-olefin compounds such as 1-butene and 1-pentene; terminal acetylene compounds such as 1-butyne; internal acetylene compounds such as 2-hexyne and 3-hexyne; propadiene, 1 Allene compounds such as 1,2-butadiene and 1,2-pentadiene; linear or cyclic non-conjugated dienes such as 1,4-pentadiene, 1,5-pentadiene, 1,5-cyclooctadiene, norbornadiene, dicyclopentadiene Compounds; and the like can be used. Among these, allene compounds and cyclic non-conjugated diene compounds are preferable, and propadiene, 1,2-butadiene, 1,2-pentadiene, and 1,5-cyclooctadiene are more preferable. These molecular weight regulators can be used alone or in combination of two or more.
[0030]
The polymerization mode may be a batch type or a continuous type, but a continuous type can be preferably employed because it is superior in productivity of high cis polybutadiene.
The polymerization temperature is usually in the range of 0 to 100 ° C, preferably 10 to 60 ° C. The polymerization pressure is usually in the range of 0 to 0.5 MPa (gauge pressure).
[0031]
In the step (B), after the polymerization is stopped, an anti-aging agent is added to the obtained high cis polybutadiene solution. If an anti-aging agent is added before the polymerization is stopped, the hue of the resulting high cis polybutadiene becomes extremely poor.
[0032]
The polymerization is preferably stopped by adding a polymerization terminator to the polymerization solution.
Examples of the polymerization terminator include monovalent lower alcohols such as methanol, ethanol and propanol; polyhydric alcohols such as ethylene glycol, propylene glycol, glycerin and polyethylene glycol; and water. Above all,
Monovalent lower alcohols are preferred, and methanol can be used more preferably.
The usage-amount of a polymerization terminator is 1-50 mol normally with respect to 1 mol of organoaluminum used for the catalyst, Preferably it is 2-30 mol.
[0033]
For the purpose of improving the mixing efficiency of the polymerization solution and the polymerization terminator, diluting with an inert solvent used for the polymerization and adding a polymerization terminator, or adding a surfactant when adding a polymerization terminator May be.
[0034]
The polymerization conversion rate when the polymerization terminator is added is preferably in the range of 20 to 90% by weight, and more preferably in the range of 50 to 80% by weight.
[0035]
After the polymerization terminator is added, it is preferable to sufficiently stir using a static mixer or a rotary stirrer so that the polymerization reaction is completely stopped.
[0036]
Examples of the antiaging agent include 2,4-bis (n-octylthiomethyl) -6-methylphenol, 2,4-bis (n-dodecylthiomethyl) -6-methylphenol, 2,4-bis ( Phenylthiomethyl) -3-methyl-6-tert-butylphenol, n-octadecyl-3- (3 ′, 5′di-tert-butyl-4′-hydroxyphenyl) propionate, tetrakis- [methylene-3- (3 ', 5'-di-tert-butyl-4'-hydroxyphenyl) propionate] -methane, 1,3,5-trimethyl-2,4,6-tris (3,5-di-tert-butyl-4- Phenol series such as hydroxybenzyl) benzene, 2,6-di-tert-butyl-4-methylphenol, 2,6-di-tert-butyl-4-ethylphenol Compound: pentaerythritol-tetrakis- (β-lauryl-thio-propionate), dilauryl-3,3′-thiodipropionate, dimyristyl-3,3′-thiodipropionate, distearyl-3,3 ′ -Sulfur-containing compounds such as thiodipropionate; phosphorus such as tris (nonylphenyl) phosphite, cyclic neopentanetetraylbis (octadecyl phosphite), tris (2,4-di-tert-butylphenyl) phosphite Containing compounds; 2- (2′-hydroxy-5′-methylphenyl) benzotriazole, 2- (2′-hydroxy-5′-tert-octylphenyl) benzotriazole, 2- (2′-hydroxy-3 ′, 5'-di-tert-butylphenyl) benzotriazole, 2- (2'-hydroxy Benzo such as 3 ′, 5′-di-tert-butylphenyl) -5-chlorobenzotriazole, 2- (2′-hydroxy-3′-tert-butyl-5′-methylphenyl) -5-chlorobenzotriazole Triazole compounds; bis (2,2,6,6-tetramethyl-4-piperidyl) sebacate, dimethyl-1- (2-hydroxyethyl) -4-hydroxy-2,2,6,6-tetramethyl succinate Piperidine polycondensate, poly [(6- (1,1,3,3-tetramethylbutyl) imino-1,3,5-triazine-2,4-diyl) [2,2,6,6-tetramethyl Hindered amine compounds such as [-4-piperidyl] imino] hexamethylene [[2,2,6,6-tetramethyl-4-piperidyl] imino]].
[0037]
The amount of the anti-aging agent used is preferably 0.05 to 3 parts by weight, more preferably 0.1 to 2 parts by weight with respect to 100 parts by weight of the high cis polybutadiene produced by polymerization.
[0038]
For the purpose of improving the mixing efficiency of the anti-aging agent and the high cis polybutadiene solution, the anti-aging agent can be added as a solution of an inert solvent used for the polymerization.
After adding the anti-aging agent, it is preferable to sufficiently stir using a static mixer or a rotary stirrer so that the mixed state of the anti-aging agent and the high cis polybutadiene solution becomes uniform.
[0039]
In the step (C), after adding water to the high cis polybutadiene solution obtained in the step (B), 10% by weight or more of the added water is discharged out of the system.
[0040]
The amount of water added is preferably 10 to 200 parts by weight, more preferably 20 to 100 parts by weight with respect to 100 parts by weight of the high cis polybutadiene solution. If the amount of water added is small, the aluminum metal content of the resulting high cis polybutadiene tends to increase, and conversely if it is large, it tends to be difficult to discharge 10% by weight or more of the added water out of the system. .
[0041]
After adding water, it is preferable to sufficiently stir using a static mixer or a rotary stirrer so that the dispersion state of water and the high cis polybutadiene solution is uniform.
[0042]
When adding water, it is preferable to use a surfactant in combination in that a high cis polybutadiene having a reduced aluminum metal content can be obtained.
[0043]
Examples of the surfactant include block condensation polymers of two or more alkylene oxides such as oxyethyleneoxypropylene block polymer; polyoxyethylene lauryl ether, polyoxyethylene cetyl ether, polyoxyethylene stearyl ether, polyoxyethylene oleyl Polyoxyalkylene ether compounds such as ether, polyoxyethylene octylphenyl ether, polyoxyethylene nonylphenyl ether; polyoxyethylene glycol monolaurate, polyoxyethylene glycol monopalmitate, polyethylene glycol monostearate, polyethylene glycol distearate Rate, polyoxyalkylene glycol fatty acid ester compounds such as polyethylene glycol monooleate;
[0044]
Glyceryl monostearate, glyceryl monooleate, sorbitan monolaurate, sorbitan monopalmitate, sorbitan monostearate, sorbitan distearate, sorbitan tristearate, sorbitan monooleate, sorbitan dioleate, mannitan monolaurate , Mannitan monostearate, mannitan distearate, mannitan monooleate, hexitan monolaurate, hexitan monopalmitate, hexitan monostearate, hexitan distearate, hexitan tristearate, hexitan Polyhydric alcohol fatty acid ester compounds such as monooleate and hexitandiolate;
[0045]
Polyoxyethylene sorbitan monolaurate, polyoxyethylene sorbitan monostearate, polyoxyethylene sorbitan distearate, polyoxyethylene sorbitan monooleate, polyoxyethylene mannitan monopalmitate, polyoxyethylene mannitan monostearate, A nonionic surfactant such as polyoxyalkylene polyhydric alcohol fatty acid ester compounds such as polyoxyethylene mannitan monooleate, polyoxyethylene hexitan monolaurate, polyoxyethylene hexitan monostearate; and
[0046]
Fatty acid salts having 5 to 50 carbon atoms such as sodium laurate, sodium myristate, sodium palmitate, sodium stearate, potassium stearate, sodium oleate, potassium oleate; higher grades having 5 to 50 carbon atoms such as sodium lauryl sulfate Anionic surfactants such as alcohol sulfates; liquid fatty oil sulfates such as sodium dodecylsulfoacetate; aromatic sulfonates such as sodium naphthalenesulfonate and sodium dodecylbenzenesulfonate; . Among these, nonionic surfactants are preferable, and polyoxyalkylene polyhydric alcohol fatty acid ester compounds can be used more preferably.
[0047]
The amount of the surfactant used is preferably 10 to 500 ppm, more preferably 20 to 200 ppm, based on the total amount of water to be added. When the amount used is large, the high cis-butadiene solution and the added water are emulsified, and it tends to be difficult to discharge a specific amount of water out of the system.
[0048]
After adding water to the high cis polybutadiene solution, a predetermined amount of the added water is discharged out of the system.
Here, discharging a predetermined amount of the added water out of the system means separating and removing a predetermined amount of water from the mixture of the high cis polybutadiene solution and the added water.
[0049]
After adding water to the high cis polybutadiene solution, the specific amount of the added water is discharged out of the system because the specific gravity of water is usually larger than the specific gravity of the high cis polybutadiene solution. It is possible to employ a method of adding water to the storage container, transferring it to a storage container, and discharging it out of the system with a pump from the water phase part separated at the lower part of the storage container while stirring under appropriate stirring conditions.
It should be noted that some amount of high cis polybutadiene solution may be dispersed in the water discharged out of the system without being separated.
[0050]
The amount of water discharged out of the system is 10% by weight or more of the added water, preferably 20 to 95% by weight, more preferably 30 to 90% by weight.
When the amount of water discharged out of the system is small, the aluminum metal content of the obtained high cis polybutadiene increases. Setting the amount of water discharged out of the system to an amount exceeding 95% by weight of the added water tends to be difficult, particularly when continuously polymerized.
[0051]
The pH of water discharged out of the system is preferably acidic, more preferably pH 2 to 6, particularly preferably pH 3 to 5. If this pH is low, the corrosion of the equipment in this process tends to be accelerated, and if it is too high, the aluminum metal content of the resulting high cis polybutadiene tends to increase. This pH can be adjusted by appropriately adjusting the amount of water to be added and the stirring conditions after the addition.
[0052]
In the step (D), the high cis polybutadiene solution obtained in the step (C) is subjected to steam stripping under an alkaline condition to separate the high cis polybutadiene. In the step (C), when the amount of water discharged out of the system is not the total amount of added water, the high cis polybutadiene solution obtained in the step (C) contains the remaining water.
[0053]
Steam stripping is usually performed in the presence of water. The amount of water used at this time is preferably 500 to 2000 parts by weight, more preferably 700 to 1500 parts by weight with respect to 100 parts by weight of the high cis polybutadiene produced by the polymerization.
[0054]
Steam stripping is essential to be performed under alkaline conditions, and the pH at this time is preferably in the range of pH 7.5 to 12, and more preferably in the range of pH 9.5 to 11. When this pH is low, the corrosion of the equipment after the steam stripping process is promoted. On the other hand, if the pH is too high, an alkali component remains in the resulting high cis polybutadiene, which may have an adverse effect depending on the application.
[0055]
It is preferable to add a base in order to maintain the alkaline conditions during the steam stripping.
Examples of the base include organic bases such as triethylamine and ethylenediamine, alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide; alkali metal carbonates such as sodium carbonate, potassium carbonate, and sodium bicarbonate. An inorganic base such as ammonia; Of these, alkali metal hydroxides can be preferably used.
The amount of the base used is preferably 0.1 to 3 mol, more preferably 0.3 to 2 mol, per 1 mol of the organoaluminum compound used as the polymerization catalyst component.
[0056]
As a method for adding a base, it may be added to the high cis polybutadiene solution obtained in the step (C), or may be added directly to a vessel for steam stripping. At this time, the base may be added as a solution dissolved in water or an organic solvent.
[0057]
The amount of steam used in the steam stripping is preferably 100 to 300 parts by weight, more preferably 150 to 250 parts by weight with respect to 100 parts by weight of the high cis polybutadiene produced by the polymerization.
The temperature of the steam is usually 110 to 270 ° C, preferably 130 to 250 ° C.
[0058]
As conditions for steam stripping, it is preferable to maintain a temperature in the system of 100 to 130 ° C. and a pressure (gauge pressure) in the system of 20 to 400 kPa.
[0059]
Steam stripping is preferably performed while stirring the system, and a crumbing agent may be used in combination.
[0060]
By performing steam stripping as described above, unreacted 1,3-butadiene and the inert solvent used in the polymerization are removed from the high cis polybutadiene solution and dispersed in water in a crumb-like state. Cis polybutadiene is separated.
[0061]
The crumb-like high cis polybutadiene obtained as described above is dehydrated so as to have a water content of 3 to 30% by weight, and further dried so as to have a water content of 1% by weight or less.
[0062]
For the dehydration, for example, a compressed water squeezer such as a roll, a Banbury dehydrator, a screw extruder squeeze dehydrator or the like can be used. Before the crumb-like high cis polybutadiene is introduced into the compressed water squeezer, the water content may be drained to 35 to 60% by weight using a rotary screen, vibrating screen, centrifugal dehydrator or the like.
[0063]
Drying can usually be performed using a screw extruder type, a kneader type dryer, an expander dryer, a hot air dryer or the like.
[0064]
The dried high cis polybutadiene is produced in the form of, for example, a veil, crumb, granule, powder, strand, or pellet.
[0065]
Depending on the purpose, the high cis polybutadiene may be, for example, a stabilizer such as a light stabilizer or an ultraviolet absorber; silica, talc, carbon, calcium carbonate, magnesium carbonate, glass fiber, carbon fiber, metal fiber, glass bead, mica. , Potassium titanate whisker, aramid fiber, wood powder, cork powder, cellulose powder, rubber powder and other fillers; plasticizers, oils, softeners such as low molecular weight polymers, etc. May be.
[0066]
The high cis butadiene in the present invention preferably has a cis bond content of 90% by weight or more, more preferably 95% by weight or more, and a number average molecular weight of preferably 5,000 to 2,000,000, more preferably 10, 000-1,000,000.
[0067]
The high cis polybutadiene obtained by the method of the present invention is used as a resin impact resistance improver, or contains a reinforcing agent such as carbon black or silica, a vulcanizing agent, a vulcanization accelerator, an anti-aging agent and the like. Can be used for rubber products such as tires, hoses, belts, and other various industrial products. Further, if necessary, it can be used by blending with other synthetic rubber and / or natural rubber.
[0068]
【Example】
Hereinafter, the present invention will be described in more detail with reference to examples. Parts and percentages in the examples are by weight unless otherwise specified. The physical properties were measured by the following methods.
[0069]
(1) Corrosion evaluation
Extract 2 kg of water-containing crumb which is extracted from the steam stripping container and squeezed by hand so that the water content is 20%. When this one is dried with a hot air dryer, a metal piece made of SS410 of 8 cm × 4 cm × 0.32 cm is placed on the wire mesh in contact with the side surface of the hydrous crumb and dried with hot air at 80 ° C.
After drying for 1 hour, only the dried rubber is taken out, and when the second hydrous crumb is dried, the same surface of the metal piece is placed on the metal mesh in contact with the side of the hydrous crumb, as described above. Dry with hot air at 80 ° C.
After the above drying operation was repeated 10 times, the surface of the metal piece in contact with the hydrated crumb was observed, and the degree of corrosion was evaluated as m.
○ ・ ・ There is no change on the surface of the test piece and no corrosion is observed.
× ·· The surface is reddish brown and corroded.
[0070]
(2) Number average molecular weight of high cis polybutadiene
High cis polybutadiene was measured by gel permeation chromatography (GPC), and the number average molecular weight in terms of standard polystyrene was determined.
GPC uses HLC-8020 (manufactured by Tosoh Corp.) and GMH-HR-H and G7000 (both manufactured by Tosoh Corp.) connected as a column, and detection uses a differential refractometer RI-8020 (manufactured by Tosoh Corp.). And measured.
(3) High cis polybutadiene cis bond content
The cis bond content of the high cis polybutadiene is ¹ Measured by H-NMR analysis.
(4) Aluminum metal content in high cis polybutadiene
The aluminum ion concentration in the aqueous solution obtained by ashing the high cis polybutadiene at 600 ° C. and dissolving it with hydrochloric acid was measured using an ICP emission analyzer (manufactured by PerkinElmer Japan Co., Ltd .: OPTIMA3300XL). Converted to metal content.
[0071]
(5) Color tone of high cis polybutadiene
The obtained high cis polybutadiene was heat-treated at 60 ° C. for 1 week in a gear oven, and then press molded using a molding die of 80 mm × 40 mm × 2 mm to prepare a test piece. The YI (yellow index) value in the transmission of the test piece was measured using a measuring device (SM color computer, model SM-4, manufactured by Suga Test Instruments Co., Ltd.), and the value of Comparative Example 1 was set to 100. Expressed as an index.
The smaller the index, the lighter the yellowish color, indicating a better color tone.
[0072]
Example 1
Two stainless steel polymerization reactors equipped with a stirrer, a cooling jacket and a reflux condenser were connected in series, and continuous polymerization was performed as follows.
A 1,3-butadiene solution containing 11% toluene, 40% cis-2-butene, 9% trans-2-butene, 6% other inert hydrocarbons such as n-butane and 34% 1,3-butadiene. A stainless steel sintered filter having a flow rate of 70 kg / h and flowing 1,2-butadiene as a molecular weight adjusting agent at 800 mmol / h, trimethyl orthoformate as a gelation inhibitor at 5 mmol / h, and a pore size of 2 microns. -2.5 g of water was added per hour through and dispersed. To this mixture was further added 350 mmol / h of diethylaluminum monochloride (as a toluene solution) and introduced into the polymerization reactor. From another pipe, 28 g / hour of cobalt octenoate 3% toluene solution was added to the polymerization reactor, and continuous polymerization was carried out for 120 hours at 20 ° C. and a residence time of 2 hours. (Process (A))
[0073]
A high cis polybutadiene solution was continuously extracted from the second polymerization reactor using a transfer pump. When extracting, from the suction side of the transfer pump, 360 g of methanol as a polymerization terminator is added in the state of 10% toluene solution per hour, and further stirred and mixed with a static mixer (number of elements: 6) connected to the discharge side of the pump. The polymerization reaction was stopped. The polymerization conversion rate at this time was 65%.
To the solution after stopping the polymerization reaction, 140 g of a 15% toluene solution of 2,4-bis (n-octylthiomethyl) -6-methylphenol as an anti-aging agent was added every hour and stirred and mixed with a dynamic mixer. (Process (B))
[0074]
Next, 50 parts of water containing 80 ppm of polyoxyethylene sorbitan monolaurate (manufactured by Kao Corporation, Rheodor TWL120) was continuously added to 100 parts of the above solution, and the mixture was equipped with a stirrer. Introduce into the middle of the storage container.
In this storage container, water separates and collects in the lower part of the storage container, and is discharged from the bottom of the storage container to the outside so that the water level is constant. The proportion of water discharged out of the system at this time was a proportion corresponding to 50% with respect to 50 parts of the water added above.
The temperature in the storage container was 25 ° C., the average residence time was 30 minutes, and the pH of the water discharged out of the system was 4.3. (Process (C))
[0075]
A high cis polybutadiene solution containing water was continuously withdrawn from the upper part of the storage container and introduced into a steam stripping container. A ratio of 1000 parts of water, 180 parts of steam (temperature 240 ° C., pressure 1020 kPa), and 0.8 parts of 10% aqueous sodium hydroxide solution to 100 parts of high cis-polybutadiene produced by polymerization in a steam stripping vessel Introduced in. The container internal temperature was 105 ° C., the container internal pressure was 320 kPa, and the average residence time was 30 minutes. (Process (D))
In this step, unreacted 1,3-butadiene and the organic solvent were removed, and high cis polybutadiene dispersed in crumb in water was obtained.
The water in the steam stripping vessel was collected and measured for pH, and it was pH 10.2. (Process (D))
[0076]
A dispersion in which high cis polybutadiene was dispersed in crumb form in water was continuously extracted from the steam stripping vessel. This dispersion was squeezed by hand to obtain a crumb having a water content of 20%. This crumb was used to evaluate corrosivity. The results are shown in Table 1. The obtained crumb was dried with hot air at 80 ° C. for 1 hour to obtain a high cis polybutadiene having a water content of 0.1%. The number average molecular weight, cis bond content, aluminum metal content, and color tone of the high cis polybutadiene were measured, and the results are shown in Table 1.
[0077]
(Example 2)
Instead of adding 140 g / h of a 15% toluene solution of 2,4-bis (n-octylthiomethyl) -6-methylphenol as an anti-aging agent, n-octadecyl-3- (3 ′-(3′-5 300 g / hour of a toluene solution containing 5% of '-di-tert-butyl-4-hydroxyphenyl) propionate and 10% of trisnonylphenyl phosphite, and the amount of water added in step (C), step (C) The same procedure as in Example 1 was conducted except that the ratio of water discharged in step 1 and the amount of sodium hydroxide added in step (D) were changed to the values shown in Table 1. The results are shown in Table 1.
[0078]
Example 3
Add in step (A), change 1,2-butadiene to 800 mmol / h, water to 2.3 g / h, diethylaluminum monochloride to 340 mmol / h (as toluene solution) and add in step (C) The same procedure as in Example 1 was conducted except that the amount of water to be discharged, the ratio of water discharged in step (C) and the amount of sodium hydroxide added in step (D) were changed to the values shown in Table 1. The results are shown in Table 1.
[0079]
(Comparative Example 1)
The same procedure as in Example 1 was performed except that the addition positions of the polymerization terminator and the anti-aging agent added in the step (B) were reversed and the following was performed. The results are shown in Table 1.
(Process (B))
A high cis polybutadiene solution was continuously withdrawn from the second polymerization reactor using a transfer pump. When extracting, 140 g of 15% toluene solution of 2,4-bis (n-octylthiomethyl) -6-methylphenol is added as an anti-aging agent from the suction side of the transfer pump and connected to the discharge side of the pump. And mixing with a static mixer (6 elements).
To this solution, 360 g of methanol as a polymerization terminator in a state of 10% toluene solution was added per hour and stirred and mixed with a dynamic mixer to terminate the polymerization reaction. The polymerization conversion rate at this time was 65%.
[0080]
(Comparative Example 2)
The same procedure as in Example 1 was performed except that the mixture of the high cis polybutadiene solution and water was introduced from the bottom of the storage container into the steam stripping container without discharging the water added in the step (C). The results are shown in Table 1.
(Comparative Example 3)
It carried out like Example 1 except not adding sodium hydroxide at a process (D). The results are shown in Table 1.
[0081]
[Table 1]

[0082]
Table 1 shows the following.
Although the high cis polybutadiene of Comparative Example 1 obtained by adding a polymerization terminator after adding an anti-aging agent to the high cis polybutadiene polymerization solution has a low aluminum metal content, the color tone is inferior.
The high cis polybutadiene of Comparative Example 2 obtained without discharging the water added in the step (C) out of the system has a good color tone but a high aluminum metal content.
In the method of Comparative Example 3 in which steam stripping is performed under acidic conditions, a crumb that easily corrodes the metal is obtained, and the corrosion of the equipment after the steam stripping step is easily promoted.
[0083]
Compared to the above comparative example, the high cis polybutadiene of Examples 1 to 3 obtained by the method defined in the present invention has a low aluminum metal content, good color tone, and crumbs that are difficult to corrode metals. Yes.
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the aluminum metal content is reduced and the manufacturing method of the high cis polybutadiene excellent in a hue is provided, suppressing the corrosion of the manufacturing equipment after the process of a steam stripping.

Claims (1)

A step (A) of polymerizing 1,3-butadiene by using a catalyst consisting essentially of a transition metal compound, an organoaluminum compound and a compound having active hydrogen in an inert solvent to produce high cis polybutadiene;
Step (B) of adding an anti-aging agent to the resulting high cis polybutadiene solution after stopping the polymerization;
Step (C) of adding 10% by weight or more of the added water out of the system after adding water to the high cis polybutadiene solution obtained in the step (B);
A step (D) of separating the high cis polybutadiene by steam stripping the high cis polybutadiene solution obtained in the step (C) under an alkaline condition;
A process for producing high cis polybutadiene.