JP6287442B2 - Catalyst removal method - Google Patents

Description

  The present invention relates to a method for removing a polymerization catalyst contained in a cement solution from a cement solution of a conjugated diene polymer.

  Conventionally, conjugated diene rubbers have been used as rubbers used for tires and the like that require a balance between impact resilience, wear resistance and low heat build-up. Such a conjugated diene rubber can be produced by a method in which a monomer containing a conjugated diene compound is polymerized in an inert solvent in the presence of a polymerization catalyst. On the other hand, in the conjugated diene rubber produced in this way, if the polymerization catalyst remains, problems occur in the post-polymerization process, or the physical properties of the rubber cross-linked product obtained from the conjugated diene rubber deteriorate. Therefore, a method for efficiently removing the polymerization catalyst from the conjugated diene rubber is required.

  On the other hand, for example, in Patent Document 1, as a method of removing the remaining polymerization catalyst from a polymer solution of a hydrogenated conjugated diene polymer, first, water is added to the polymer solution, By applying a shearing force to the combined solution and water and mixing them, the polymer catalyst is transferred to water, and then the mixed polymer solution and water are allowed to stand. And a method for removing the aqueous phase is disclosed.

Japanese Examined Patent Publication No. 7-64889

  However, in the catalyst removal method described in Patent Document 1, it takes time to separate the polymer solution phase and the aqueous phase, and therefore it is necessary or impossible to enlarge the tank for separation. Has a problem that the aqueous phase containing the polymerization catalyst remains in the polymer solution phase, and the removal efficiency of the polymerization catalyst is low.

  The present invention provides a conjugated diene polymer solution obtained by polymerizing a monomer containing at least a conjugated diene compound in an inert solvent using a polymerization catalyst, and remaining in the conjugated diene polymer solution. An object of the present invention is to provide a catalyst removal method capable of efficiently removing a polymerization catalyst.

  The present inventors added a treatment liquid containing a surfactant and water to the conjugated diene polymer solution, and after mixing these at a temperature below the cloud point of the surfactant, It was found that the above object could be achieved by separating the conjugated diene polymer solution phase and the aqueous phase by standing at a temperature equal to or higher than the cloud point of the surfactant, and the present invention was completed. .

  That is, according to the present invention, from the conjugated diene polymer solution obtained by polymerizing a monomer containing at least a conjugated diene compound using a polymerization catalyst in an inert solvent, the conjugated diene polymer is obtained. A method of removing the polymerization catalyst remaining in a solution, wherein a treatment liquid containing a surfactant and water is added to the conjugated diene polymer solution, and the temperature is lower than the cloud point of the surfactant. A mixing step of transferring the polymerization catalyst in the conjugated diene polymer solution to water in the treatment liquid by mixing the conjugated diene polymer solution and the treatment liquid, and the conjugated diene system A separation step of separating the conjugated diene polymer solution phase and the aqueous phase by allowing the mixed solution of the polymer solution and the treatment liquid to stand at a temperature equal to or higher than the cloud point of the surfactant. It is characterized by having Medium removal method is provided.

In the present invention, it is preferable to use a nonionic surfactant as the surfactant.
Moreover, in this invention, it is preferable to use the aqueous solution which made the density | concentration of the said surfactant 5-1000 ppm by weight as said process liquid.

  According to the present invention, from a conjugated diene polymer solution obtained by polymerizing a monomer containing a conjugated diene compound in an inert solvent using a polymerization catalyst, the monomer remains in the conjugated diene polymer solution. It is possible to efficiently remove the polymerization catalyst.

Conjugated Diene Polymer First, the conjugated diene polymer used in the present invention will be described.
The conjugated diene polymer used in the present invention is obtained by polymerizing a monomer containing at least a conjugated diene compound by a solution polymerization method using a polymerization catalyst in an inert solvent. The conjugated diene polymer used in the present invention may be a homopolymer obtained by polymerizing one kind of conjugated diene compound, or a copolymer obtained by polymerizing two or more kinds of conjugated diene compounds. Alternatively, it may be any copolymer obtained by copolymerizing a conjugated diene compound and another monomer copolymerizable with the conjugated diene compound.

  The conjugated diene compound used for polymerization is not particularly limited, and for example, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 2-methyl-3-ethyl- Examples include 1,3-butadiene, 2-methyl-1,3-pentadiene, 1,3-hexadiene, and 1,3-cyclohexadiene. Among these, 1,3-butadiene, isoprene and 1,3-pentadiene are preferable, and 1,3-butadiene and isoprene are particularly preferable. In addition, these conjugated diene compounds may be used individually by 1 type, and may be used in combination of 2 or more type.

  Although it does not specifically limit as another monomer which can be copolymerized, An aromatic vinyl compound can be mentioned suitably. The aromatic vinyl compound is not particularly limited, and for example, styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2-ethylstyrene, 3-ethylstyrene, 4-ethylstyrene. 2,4-diisopropylstyrene, 2,4-dimethylstyrene, 4-t-butylstyrene, 5-t-butyl-2-methylstyrene, vinylnaphthalene, dimethylaminomethylstyrene, dimethylaminoethylstyrene, etc. Can do. Among these, styrene, α-methylstyrene, and 4-methylstyrene are preferable, and styrene is particularly preferable. Note that. These aromatic vinyl compounds may be used individually by 1 type, and may be used in combination of 2 or more type.

  The content ratio of the conjugated diene monomer unit in the conjugated diene polymer used in the present invention is preferably 50 to 100% by weight, more preferably 55 to 100% by weight, and the aromatic vinyl compound is contained. The proportion is preferably 0 to 50% by weight, more preferably 0 to 45% by weight.

  Examples of monomers other than aromatic vinyl compounds include α, β-unsaturated nitriles such as acrylonitrile and methacrylonitrile; unsaturated carboxylic acids such as acrylic acid, methacrylic acid, and maleic anhydride, or acid anhydrides. Unsaturated carboxylic acid esters such as methyl methacrylate, ethyl acrylate and butyl acrylate; 1,5-hexadiene, 1,6-heptadiene, 1,7-octadiene, dicyclopentadiene, 5-ethylidene-2-norbornene, etc. Non-conjugated dienes; and the like. These monomers are preferably 10% by weight or less, more preferably 5% by weight or less as monomer units in the conjugated diene polymer.

  The inert solvent used for the polymerization is not particularly limited as long as it is one usually used in the solution polymerization method and does not inhibit the polymerization reaction. Specific examples of the inert solvent include chain aliphatic hydrocarbons such as butane, pentane, hexane, heptane, 1-butene, 2-butene, 1-pentene and 2-pentene; fats such as cyclopentane, cyclohexane and cyclohexene Cyclic hydrocarbons; aromatic hydrocarbons such as benzene, toluene, xylene; and the like. These inert solvents may be used individually by 1 type, and may be used in combination of 2 or more type. The amount of the inert solvent used is such that the monomer concentration is, for example, 1 to 50% by weight, preferably 10 to 40% by weight.

  The polymerization catalyst is not particularly limited as long as it can give a conjugated diene polymer by polymerizing each of the above-mentioned monomers. For example, a main catalyst composed of a transition metal compound, and organic aluminum A co-catalyst composed of a compound can be used.

  Examples of the transition metal compound used as the main catalyst include compounds such as cobalt, nickel, vanadium, titanium, lanthanum, cerium, praseodymium, neodymium, samarium, and gadolinium. Especially, as a transition metal compound, a cobalt compound or a nickel compound is preferable, and a cobalt compound is more preferable. A transition metal compound may be used individually by 1 type, and may be used in combination of 2 or more types.

  Cobalt compounds include cobalt halide salts such as cobalt chloride and cobalt bromide; organic acid cobalt salts such as cobalt octenoate, cobalt naphthenate, cobalt acetate and cobalt malonate; cobalt bisacetylacetonate and cobalt trisacetylacetonate Cobalt complexes such as cobalt acetoacetate, cobalt trihalylphosphine complex of cobalt halide, trialkylphosphine complex of cobalt halide, pyridine complex of cobalt salt, picoline complex of cobalt salt, ethyl alcohol complex of cobalt salt, etc. Can be mentioned. Especially, as a cobalt compound, octenoic acid cobalt is preferable.

  Examples of nickel compounds include nickel naphthenate, nickel formate, nickel octylate, nickel stearate, nickel citrate, nickel benzoate, nickel toluate, etc .; organic complexes such as nickel acetylacetonate; alkylbenzene sulfonic acid Examples thereof include nickel and nickel oxyborate. Of these, nickel naphthenate is preferable as the nickel compound.

  As the organoaluminum compound used as a cocatalyst, either one or both of a non-halogenated organoaluminum compound and a halogenated organoaluminum compound can be used, but it is preferable that at least a halogenated organoaluminum compound is included. Non-halogenated organoaluminum compounds include trialkylaluminum; organoaluminum hydrides such as dialkylaluminum hydride and alkylaluminum sesquihydride. Examples of the halogenated organic aluminum include dialkylaluminum chloride, dialkylaluminum bromide, alkylaluminum dichloride, alkylaluminum dibromide, alkylaluminum sesquichloride, and alkylaluminum sesquibromide.

  Specific examples of organoaluminum compounds include trimethylaluminum, triethylaluminum, triisobutylaluminum, trihexylaluminum, trioctylaluminum, tridecylaluminum, dimethylaluminum chloride, diethylaluminum chloride, ethylaluminum sesquichloride, ethylaluminum dichloride, diethylaluminum. Examples include hydride, diisobutylaluminum hydride, and ethylaluminum sesquihydride. As the non-halogenated organoaluminum compound, trialkylaluminum is preferable, and triethylaluminum is more preferable. As the halogenated organoaluminum compound, organoaluminum chloride is preferred, and diethylaluminum chloride is more preferred.

  Alternatively, as the polymerization catalyst, in addition to the transition metal compound (main catalyst) and the organoaluminum compound (promoter) described above, an organic alkali metal compound, an organic alkaline earth metal compound, or the like can be used. Examples of the organic alkali metal compound include organic monolithium compounds such as n-butyllithium, sec-butyllithium, t-butyllithium, hexyllithium, phenyllithium and stilbenelithium; dilithiomethane, 1,4-dilithiobutane, 1,4 -Organic polyvalent lithium compounds such as dilithio-2-ethylcyclohexane, 1,3,5-trilithiobenzene, 1,3,5-tris (lithiomethyl) benzene; organic sodium compounds such as sodium naphthalene; organic such as potassium naphthalene Potassium compounds; and the like. Examples of the organic alkaline earth metal compound include di-n-butylmagnesium, di-n-hexylmagnesium, and diethylbarium. Among these organic alkali metal compounds and organic alkaline earth metal compounds, organic monolithium compounds and organic polylithium compounds are preferred, organic monolithium compounds are more preferred, and n-butyllithium is particularly preferred. The organic alkali metal compound is used as an organic alkali metal amide compound by previously reacting with a secondary amine such as dibutylamine, dihexylamine, dibenzylamine, pyrrolidine, hexamethyleneimine, and heptamethyleneimine. Also good. One of these organic alkali metal compounds and organic alkaline earth metal compounds may be used alone, or two or more thereof may be used in combination.

  The amount of the polymerization catalyst used may be determined according to the molecular weight of the target polymer, but is usually 1 to 200 mmol, preferably 1.5 to 100 mmol, more preferably 2 to 1000 g per monomer. It is in the range of 40 mmol.

  The temperature for carrying out the polymerization is usually in the range of −80 to + 150 ° C., preferably 0 to 100 ° C., more preferably 10 to 90 ° C. As the polymerization mode, any mode such as batch mode or continuous mode can be adopted.

  The production method of the conjugated diene polymer used in the present invention is not particularly limited, but the monomer containing the conjugated diene compound is polymerized in the above-mentioned inert solvent by a known solution polymerization method, Examples thereof include a method obtained in the form of a cement solution in which a conjugated diene polymer is dissolved.

  As described above, a conjugated diene polymer can be obtained by polymerizing a monomer containing a conjugated diene compound.

  Further, the weight average molecular weight (Mw) detected by gel permeation chromatography (hereinafter also referred to as GPC) of the conjugated diene polymer is preferably 10,000 to 1,000,000 as a value in terms of polystyrene. Preferably it is 50,000-850,000, More preferably, it is 100,000-700,000.

  Furthermore, the molecular weight distribution represented by the ratio (Mw / Mn) of the weight average molecular weight (Mw) and the number average molecular weight (Mn) of the conjugated diene polymer is preferably 1.0 to 5.0, more preferably 1 0.0 to 4.0, particularly preferably 1.0 to 3.0.

Catalyst Removal Method The catalyst removal method of the present invention contains a surfactant and water for the conjugated diene polymer solution obtained by polymerizing a conjugated diene compound in the presence of a polymerization catalyst as described above. A polymerization catalyst remaining in the conjugated diene polymer solution by adding the treatment liquid and mixing the conjugated diene polymer solution and the treatment liquid at a temperature below the cloud point of the surfactant in the treatment liquid. By mixing the conjugated diene polymer solution and the treatment liquid at a temperature equal to or higher than the cloud point of the surfactant. And a separation step of separating the aqueous polymer solution phase and the aqueous phase.

First, the mixing process for transferring the polymerization catalyst in the conjugated diene polymer solution to the water in the treatment liquid will be described.
In the present invention, a treatment liquid containing a surfactant and water is added to the conjugated diene polymer solution, and the conjugated diene polymer solution and the treatment are performed at a temperature below the cloud point of the surfactant in the treatment liquid. By mixing with the liquid, the polymerization catalyst in the conjugated diene polymer solution is transferred to the water in the treatment liquid. In the present invention, the temperature at the time of mixing the conjugated diene polymer solution and the treatment liquid is set to a temperature lower than the cloud point of the surfactant contained in the treatment liquid, and the mixture is less than the cloud point. As a result, the surfactant can form micelles, whereby the conjugated diene polymer solution mixes well with the treatment liquid (particularly, water constituting the treatment liquid), and the conjugated diene polymer solution The polymerization catalyst contained in can be transferred to water in the treatment liquid.

  The surfactant used in the present invention may be selected according to the type of conjugated diene polymer, and anionic surfactants, cationic surfactants, and nonionic surfactants are used.

Examples of the anionic surfactant include fatty acid salts (RCOOM), higher alcohol sulfate esters (ROSO ₃ M), liquid fatty oil sulfate esters [R (OSO ₃ M) COOR], aliphatic amines and aliphatic amides. Sulfates (RCONHR′CH ₂ CH ₃ OSO ₃ M), aliphatic alcohol phosphates [ROP (OM) ₂ ], dibasic fatty acid sulfonates [ROCOCH ₂ —CH (SO ₃ M) COCOR ′ ], fatty acid amide sulfonic acid salts _{(RCONR'CH 2 CH 2 SO 3 M} ), and the like alkylaryl sulfonate _{(R-Ph-SO 3 M} ). These may be used in the form of free acid. M in the above formula represents an alkali metal such as sodium or potassium; ammonium or the like.

  In addition, as the anionic surfactant, a polymer type anionic surfactant can be used, for example, polycarboxylic acid and salts thereof; sulfonic acid group-containing polymer and salts thereof; carboxymethylcellulose, sodium alginate, And other anionic polymers such as rosin soap. Examples of polycarboxylic acids and salts thereof include polymers of (meth) acrylic acid and salts thereof; polymers of unsaturated dibasic acids such as maleic anhydride, maleic acid, fumaric acid and itaconic acid, or other monomers Or a salt thereof. Examples of the sulfonic acid group-containing polymer include lignin sulfonic acid, naphthalene (or alkylnaphthalene) sulfonic acid formalin condensate, benzene (or alkylbenzene) sulfonate, benzene (or alkylbenzene) sulfonic acid formalin condensate, Examples include a formalin condensate of aromatic sulfonic acid such as a formalin condensate of a sulfonated sort oil, and a polymer of vinyl sulfonic acid. Alternatively, as the anionic surfactant, polyoxyethylene fatty alcohol ether sulfate or a salt thereof, alkylphenol polyethylene oxide phosphate or a salt thereof, a copolymer of diisobutylene and maleic anhydride or a salt thereof, styrene and maleic anhydride Or a copolymer thereof. These anionic surfactants can be used alone or in combination of two or more, and among them, higher alcohol sulfates, polycarboxylic acids and salts thereof are preferable.

Examples of the cationic surfactant include aliphatic amine salts [N (R ¹ R ² R ³ ) · X]; fatty acid amine salt or amidopyridinium salt; lauryltrimethylammonium chloride, stearyltrimethylammonium chloride, cetyltrimethylammonium Quaternary ammonium salts such as chloride and distearyldimethylammonium chloride; alkylpyridinium salts; alkylamine benzyl salts; polyoxyethylene alkylamine salts; imidazoline derivatives and the like are used, and among these, quaternary ammonium salts are preferable. Cationic polymers such as polyvinyl pyridine polysoap, acrylic ester cationic activator, polyacrylamide cationic activator can also be used. These cationic surfactants can be used alone or in combination of two or more.

  Nonionic surfactants include, for example, sorbitan fatty acid esters, polyethylene oxide glycerin fatty acid esters, polyethylene oxide higher alcohol ethers, polyethylene oxide alkylphenol ethers, block polymers of polyethylene oxide and polypropylene oxide, polyoxyethylene polyoxypropylene glycol, and the like. Can be mentioned. These nonionic surfactants are used alone or in combination of two or more.

  In the present invention, among these anionic surfactants, cationic surfactants, and nonionic surfactants, by changing the temperature according to the cloud point, the conjugated diene polymer solution phase and the aqueous phase Nonionic surfactants are particularly preferred from the viewpoint that the compatibility of the conjugated diene polymer can be easily controlled and the polymerization catalyst remaining in the conjugated diene polymer solution can be removed more appropriately. That is, by using a nonionic surfactant as a surfactant, the temperature at the time of mixing is included in the treatment liquid when the conjugated diene polymer solution and the treatment liquid are mixed in the mixing step described above. By setting the temperature below the cloud point of the nonionic surfactant, the function of compatibilizing the conjugated diene polymer solution phase of the nonionic surfactant and the aqueous phase acts, and good mixing is possible. It becomes. In addition, after such a mixing step, in a separation step to be described later, when a mixed liquid obtained by mixing the conjugated diene polymer solution and the treatment liquid is separated into a conjugated diene polymer solution phase and an aqueous phase. In addition, by heating the mixed liquid to a temperature higher than the cloud point of the nonionic surfactant, the function of compatibilizing the conjugated diene polymer solution phase and the aqueous phase of the nonionic surfactant is reduced. Thus, the conjugated diene polymer solution phase and the aqueous phase can be satisfactorily separated, and the polymerization catalyst remaining in the conjugated diene polymer solution can be more appropriately removed.

  Further, as the surfactant used in the present invention, those having a cloud point of preferably 10 to 80 ° C., more preferably 15 to 70 ° C., and further preferably 20 to 60 ° C. are used. When the cloud point exceeds the above range, particularly 80 ° C., the vapor pressure of the solvent becomes higher than necessary in the separation step described later, or after the separation step, the solvent volatilizes and the conjugated diene polymer solution There is a possibility that problems such as an increase in viscosity and difficulty in transfer occur.

  In the present invention, the concentration of the surfactant in the treatment liquid added to the conjugated diene polymer solution is preferably 5 to 1000 ppm by weight, more preferably 10 to 500 ppm by weight, and still more preferably 20 to 200 wt. ppm. By setting the concentration of the surfactant in the treatment liquid within the above range, the mixture of the conjugated diene polymer solution and the treatment liquid is allowed to stand at a temperature equal to or higher than the cloud point of the surfactant. When the polymer solution phase and the aqueous phase are separated, the separation can be performed satisfactorily, whereby the polymerization catalyst can be more appropriately removed from the conjugated diene polymer solution.

  The amount of the treatment liquid added to the conjugated diene polymer solution is a weight ratio (treatment liquid amount / conjugated diene polymer solution amount) to the amount of the conjugated diene polymer solution, preferably 0.1 to 0.1%. 2, more preferably 0.2 to 1. When the aqueous phase is separated and removed from the mixed liquid of the conjugated diene polymer solution and the treatment liquid by setting the weight ratio of (the amount of the treatment liquid / the amount of the conjugated diene polymer solution) within the above range. In addition, the amount of the treatment liquid to be removed can be made smaller, which makes it possible to efficiently remove the polymerization catalyst while reducing the labor of drainage.

A method of mixing the conjugated diene polymer solution and the treatment liquid is not particularly limited, and examples thereof include a method of introducing the conjugated diene polymer solution and the treatment liquid into a known mixing apparatus and mixing them. As the mixing apparatus, for example, a high-speed rotary continuous mixer, a multiblade continuous mixing tank, a normal stirring tank type mixer, a static mixer (line mixer), or the like can be used.
The mixing speed at the time of mixing may be appropriately determined according to the mixer to be used, but the mixing speed (stirring speed) in the case of using a stirring tank type mixer is preferably 1 to 100 rpm, more preferably 5 to 50 rpm. It is.

  The mixing temperature when mixing the conjugated diene polymer solution and the treatment liquid in the mixing step may be a temperature lower than the cloud point of the surfactant contained in the treatment liquid, preferably the cloud point. The temperature is 10 ° C. or lower, more preferably 20 ° C. or lower than the cloud point. The lower limit of the mixing temperature is preferably 0 ° C. By setting the mixing temperature in the above range, the conjugated diene polymer solution phase of the surfactant and the aqueous phase can be appropriately mixed, and the mixing of the conjugated diene polymer solution and the treatment liquid can be further improved. It can be done well.

  The mixing time for mixing the conjugated diene polymer solution and the treatment liquid depends on the type of conjugated diene polymer contained in the conjugated diene polymer solution and the type of surfactant in the treatment liquid. In addition, the time during which the conjugated diene polymer solution and the treatment liquid can be sufficiently mixed may be set depending on the mixing method. -180 minutes, more preferably 5-120 minutes.

Next, a separation process for separating the conjugated diene polymer solution phase and the aqueous phase from the mixed liquid obtained by mixing the conjugated diene polymer solution and the treatment liquid will be described.
In the present invention, the mixed liquid obtained by mixing the conjugated diene polymer solution and the treatment liquid is heated and allowed to stand in a state where the temperature is equal to or higher than the cloud point of the surfactant contained in the treatment liquid. Thus, the conjugated diene polymer solution phase and the aqueous phase are separated.

  In the present invention, at a temperature higher than the cloud point of the surfactant, specifically, the surfactant does not form a micelle by breaking a hydrogen bond with a water molecule at a temperature higher than the cloud point of the surfactant. Paying attention to the characteristic that the function of compatibilizing the coalescence solution phase and the aqueous phase is reduced, using this characteristic, a mixed liquid obtained by mixing the conjugated diene polymer solution and the treatment liquid is added to the treatment liquid. By leaving it in a state of being heated to a temperature equal to or higher than the cloud point of the surfactant, the compatibility between the conjugated diene polymer solution phase and the aqueous phase is lowered, and thereby the conjugated diene polymer solution phase Appropriate separation from the aqueous phase. As a result, the aqueous phase in which the polymerization catalyst is transferred and the conjugated diene polymer solution phase can be appropriately separated, and as a result, the polymerization catalyst is efficiently removed from the conjugated diene polymer solution. can do.

  In the separation step, the temperature at which the liquid mixture of the conjugated diene polymer solution and the treatment liquid is allowed to stand may be a temperature equal to or higher than the cloud point of the surfactant contained in the treatment liquid. The temperature is 10 ° C. higher than the cloud point, more preferably 20 ° C. higher than the cloud point. By setting the temperature at the time of standing within the above range, the compatibility between the conjugated diene polymer solution phase and the aqueous phase can be reduced, and the conjugated diene polymer solution phase and the aqueous phase can be further reduced. It will be possible to separate properly. In addition, the upper limit of the temperature at the time of standing is preferably 90 ° C. When the temperature at the time of standing is too high, the solvent is easily vaporized, and there is a possibility that the conjugated diene polymer in a state where the polymerization catalyst is not removed is precipitated.

  In addition, the standing time when the liquid mixture of the conjugated diene polymer solution and the treatment liquid is allowed to stand at a temperature equal to or higher than the cloud point of the surfactant is the conjugated diene polymer weight contained in the conjugated diene polymer solution. The time for sufficiently separating the conjugated diene polymer solution phase and the aqueous phase may be set according to the type of coalescence and the type of surfactant in the treatment liquid, but preferably 0.5. -30 minutes, more preferably 1-15 minutes.

  According to the present invention, first, a treatment liquid containing a surfactant and water is added to the conjugated diene polymer solution of the conjugated diene polymer by the mixing step described above, and the surfactant is less than the cloud point of the surfactant. By mixing the conjugated diene polymer solution and the treatment liquid at a temperature, the polymerization catalyst in the conjugated diene polymer solution can be favorably transferred to the water in the treatment liquid. By leaving the mixed solution of the conjugated diene polymer solution and the treatment liquid at a temperature equal to or higher than the cloud point of the surfactant in the treatment liquid by the separation step, the conjugated diene polymer solution phase and the aqueous phase Can be separated satisfactorily. Therefore, according to the present invention, it is possible to efficiently remove the polymerization catalyst from the conjugated diene polymer solution.

  Hereinafter, the present invention will be described based on more specific examples, but the present invention is not limited to these examples. In the following, “part” and “%” are based on weight unless otherwise specified.

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. While flowing through the pipe at a flow rate of 70,000 parts per hour, 1,2-butadiene as a molecular weight regulator is 800 millimole parts per hour (however, the relationship between the “parts (parts by weight)” and the “mole parts” is And a ratio of 800 mmol of 1,2-butadiene with respect to 70 kg of the 1,3-butadiene solution), and sintering of stainless steel with 5 mmole of trimethyl orthoformate as a gelation inhibitor per hour and a pore diameter of 2 μm. Through the filter, 2.5 parts of water was added per hour and dispersed. To this mixture was further added 350 mmol parts of diethylaluminum monochloride (as a toluene solution) per hour, which was introduced into the polymerization reactor. From another pipe, 28 parts of cobalt octenoate 3% toluene solution was added to the polymerization reactor per hour, and continuous polymerization was carried out for 120 hours at 20 ° C. and a residence time of 2 hours. A solution of high cis polybutadiene rubber was continuously withdrawn from the second polymerization reactor using a transfer pump. When extracting, from the suction side of the transfer pump, methanol as a polymerization terminator is added 360 parts per hour in the form of a 10% toluene solution, and further stirred and mixed with a static mixer (6 elements) connected to the discharge side of the pump. Then, the polymerization reaction was stopped. The polymerization conversion rate at this time was 65%.

The solution of high cis polybutadiene rubber obtained above was introduced into a steam stripping vessel. Into a steam stripping vessel, 100 parts of a high cis polybutadiene rubber solution produced by polymerization is introduced in terms of solid content, and 1000 parts of water, 180 parts of steam (temperature 240 ° C., pressure 1020 kPa), Sodium oxide 10% aqueous solution was introduced at a ratio of 0.8 part. The container internal temperature was 105 ° C., the container internal pressure was 320 kPa, and the average residence time was 30 minutes. In this step, unreacted 1,3-butadiene and organic solvent were removed, and a high cis polybutadiene rubber dispersed in crumb form in water was obtained. From the steam stripping vessel, a dispersion in which the high cis polybutadiene rubber was dispersed in crumb form in water was continuously extracted. This dispersion was squeezed to obtain a crumb having a water content of 20%. The obtained crumb was dried with hot air at 80 ° C. for 1 hour to obtain a high cis polybutadiene rubber having a water content of 0.1%.
100 parts of this high cis polybutadiene rubber was dissolved in 590 parts of cyclohexane to obtain a cyclohexane solution of high cis polybutadiene rubber.

  Then, a part of the cyclohexane solution of the obtained high cis polybutadiene rubber was incinerated, and the aluminum ion concentration in an aqueous solution obtained by dissolving this with hydrochloric acid was measured by ICP-AES method, and the concentration of contained aluminum (Al Concentration) and amount (Al amount) were measured. The results are shown in Table 1.

  Next, in a 100 ml ampoule bottle purged with nitrogen, 50.51 g of the cyclohexane solution of the above high cis polybutadiene rubber and a surfactant having a cloud point of 58 ° C. (“Pluronic® L-64” (polyoxyethylene poly Oxypropylene glycol, nonionic surfactant (manufactured by ADEKA)) was charged with a treatment liquid (surfactant concentration 72 wt ppm) dissolved in 13.80 g of water, and this ampule bottle was heated to 30 ° C. The cyclohexane solution of the high cis polybutadiene rubber and the treatment liquid were mixed by rotating for 120 minutes at a stirring speed of 16 rpm in the constant temperature water bath.

  Thereafter, the cyclohexane solution of the high cis polybutadiene rubber and the treatment liquid were heated and left at 70 ° C. for 2 minutes to separate the cyclohexane solution phase and the aqueous phase of the high cis polybutadiene rubber. . Here, the amount of the separated treatment liquid was 9 g, and the ratio (separation ratio) to moisture in the treatment liquid before mixing with the cyclohexane solution of the high cis polybutadiene rubber was 65.2%. And the water phase isolate | separated from the liquid mixture was taken out, the weight of the isolate | separated water phase, the density | concentration (Al density | concentration) of aluminum contained in the isolate | separated water phase, and aluminum content (Al amount) were measured. Note that the Al concentration and the Al amount in the separated aqueous phase were measured by the ICP-AES method. Further, based on the amount of Al in the separated aqueous phase and the amount of Al in the cyclohexane solution of the high cis polybutadiene rubber before separation, the amount of Al in the separated aqueous phase / high cis before separation The calculated value of the amount of Al in the cyclohexane solution of the polybutadiene rubber was determined as the ratio of the amount of Al that could be removed from the cyclohexane solution of the high cis polybutadiene rubber (Al removal rate). The results are shown in Table 1.

Examples 2 and 3
Evaluation was made in the same manner as in Example 1 except that the total amount of the high cis polybutadiene rubber cyclohexane solution used, and the amount of water and the amount of the surfactant mixed in the cyclohexane solution of the high cis polybutadiene rubber were changed as shown in Table 1. Went. The results are shown in Table 1.

Comparative Example 1
The total amount of the cyclohexane solution of the high cis polybutadiene rubber to be used is changed as shown in Table 1, and the temperature when the liquid mixture of the cyclohexane solution of the high cis polybutadiene rubber and the treatment liquid is allowed to stand is determined by the cloud point of the surfactant. Evaluation was performed in the same manner as in Example 1 except that the temperature was changed to 25 ° C., which is the following temperature. The results are shown in Table 1.

Comparative Example 2
Evaluation was performed in the same manner as in Example 1 except that the total amount of the cyclohexane solution of the high cis polybutadiene rubber to be used was changed as shown in Table 1 and water to which a surfactant was not added was used as the treatment liquid. . The results are shown in Table 1.

  As shown in Table 1, a treatment liquid containing a surfactant and water was added to a cyclohexane solution of a high cis polybutadiene rubber, and these were mixed at a temperature below the cloud point of the surfactant. When allowed to stand at a temperature above the cloud point of the activator, the aqueous phase can be properly separated from the mixture of the cyclohexane solution of high cis polybutadiene rubber and the treatment liquid, and the polymerization promoter The removal rate (Al removal rate) of Al derived from the organoaluminum compound used as the high was high, and the removal efficiency of the polymerization catalyst remaining in the cyclohexane solution of the high cis polybutadiene rubber was high (Examples 1 to 3). .

  On the other hand, when the liquid mixture obtained by mixing the cyclohexane solution of high cis polybutadiene rubber and the treatment liquid is allowed to stand at a temperature lower than the cloud point of the surfactant, the Al concentration of the separated aqueous phase And the amount of the separated aqueous phase was small, the Al removal rate was low, and the removal efficiency of the polymerization catalyst remaining in the cyclohexane solution of the high cis polybutadiene rubber was low (Comparative Example 1). In addition, when water to which a surfactant is not added is used as the treatment liquid, similarly, the Al removal rate is low, and the removal efficiency of the polymerization catalyst remaining in the cyclohexane solution of the high cis polybutadiene rubber is low. (Comparative Example 2).

Claims (3)

The polymerization catalyst remaining in the conjugated diene polymer solution from a conjugated diene polymer solution obtained by polymerizing a monomer containing at least a conjugated diene compound using an polymerization catalyst in an inert solvent. A method of removing
A treatment liquid containing a surfactant and water is added to the conjugated diene polymer solution, and the conjugated diene polymer solution and the treatment liquid are mixed at a temperature below the cloud point of the surfactant. A mixing step of transferring the polymerization catalyst in the conjugated diene polymer solution to water in the treatment liquid;
Separation that separates the conjugated diene polymer solution phase from the aqueous phase by allowing the mixed solution of the conjugated diene polymer solution and the treatment liquid to stand at a temperature equal to or higher than the cloud point of the surfactant. And a step of removing the catalyst.   The catalyst removal method according to claim 1, wherein a nonionic surfactant is used as the surfactant.   The catalyst removal method according to claim 1 or 2, wherein an aqueous solution having a concentration of the surfactant of 5 to 1000 ppm by weight is used as the treatment liquid.