KR100834962B1 - Process for producing coupled vinyl aromatic-conjugated diene random copolymers - Google Patents

Abstract

A method for preparing a coupled vinyl aromatic-conjugated diene random copolymer is provided to allow production of a binary copolymer under the same productivity as a conventional batch process, to increase the number of coupling branches of a copolymer, and to realize improved mechanical properties and eco-friendly characteristics. A method for preparing a coupled vinyl aromatic-conjugated diene random copolymer comprises the steps of: carrying out solution polymerization of a conjugated diene monomer and a vinyl aromatic monomer in a hydrocarbon solvent containing, as a randomizing agent, an alkali metal alkoxide represented by the following formula 1 and an organolithium compound to obtain a living polymer; and coupling the living polymer with a halide compound represented by the formula of YCl4 or (X)a(R1)bY-[CH2]c-Si(R2)(R3)-[O-Si(R2)(R3)]d-[CH2]c-Y(X)a(R1)b as a coupling agent. In the formulae, M is a Group 1 metal element in the Periodic Table; X is a halogen atom selected from F, Cl, Br and I; Y is Si or C; R1 is selected from a C1-C20 alkyl; R2 is H, a C1-C20 alkyl, halogen-substituted C1-C20 alkyl and halogen-substituted silane group; R3 is selected from the group consisting of a halogen atom selected from F, Cl, Br and I, H, C1-C20 alkyl, halogen-substituted C1-C20 alkyl and halogen-substituted silane group; a is a number of 1-3; a+b=3; c is a number of 1-1000; and d is a number of 1-50000.

Description

Process for producing coupled vinyl aromatic-conjugated diene random copolymers

The present invention relates to a method for preparing a coupled vinylaromatic-conjugated diene random copolymer, wherein a batch solution polymerization reaction produces a copolymer in which a vinylaromatic monomer and a conjugated diene monomer are randomly formed and form a polyvalent coupling bond. It is about a method.

Recently, vinylaromatic-conjugated diene copolymers which are usefully used as rubbers for silica tire treads are prepared by solution polymerization in an organic solvent using an organolithium catalyst. This is because it is possible to satisfy the characteristics required in the tire by freely adjusting the molecular structure and shape of the vinyl structure of the conjugated diene, the block rate of the vinyl aromatic monomer, imparting functional groups, etc., which cannot be controlled by the conventional emulsion polymerization method.

When rubber prepared by solution polymerization is used for tires, the rotational and wetting resistance are particularly superior to emulsion-polymerized styrene-butadiene rubber (SBR), and the low temperature flowability at room temperature is achieved by introducing various functional groups at the molecular ends. In addition to controlling the flow, it is possible to improve the dispersibility of the reinforcement by increasing the compatibility with the reinforcement used during tire processing, and ultimately, the tire wear characteristics, rolling resistance and It shows the effect of improving the wet traction characteristics and the like.

In the early stage of solution polymerization S-SBR development, it was developed as an alternative to E-SBR, but gradually introduced energy concept into tires. Various products have been developed to satisfy the various characteristics.

In general, when a conjugated diene monomer and a styrene monomer are simply copolymerized in a reactor without adding a randomizing agent, it is determined by the difference in polymerization rate between the two monomers (Journal of Polymer Science Part A Vol. 3., PP. 153-161 (1965). The conjugated diene completes the reaction first, and the reaction proceeds in the form of a copolymer in which a part of the styrene monomer forms a block at the end of the reaction. Rubber containing such a styrene block is a factor that increases the heat generation of the tire when used as a tire material, causing a safety problem, so rubber with a block rate of 5% or more is not generally used as a tire material. In other words, the copolymer of the tire material is a random copolymer is advantageous.

For this reason, various methods have been developed to control the random properties and microstructures when preparing S-SBR by solution polymerization method. The vinyl content is controlled by random copolymerization of styrene and butadiene using THF, a Lewis base. Technology first preceded (US 2975160).

In general, in order to increase the vinyl content of the copolymer using THF, an excessive amount of THF (3000 to 30000 ppm relative to the organic solvent) should be used, and if a small amount is used, the styrene block may not be generated because the random characteristic of the THF is inferior. have. In addition, THF has a problem of contaminating the organic solvent because it is azeotropic with the organic solvent in the organic solvent recovery process.

In the prior art, a technique for preparing a styrene-butadiene random copolymer without increasing the vinyl content of a copolymer using a metal alkoxide compound (US3294768) and a metal alkoxide compound as a randomizing agent and an amine-based Lewis base TMEDA as a vinyl content regulator The technique of producing a random vinyl copolymer with high vinyl content was also preceded (US5620939), but when the prior art is applied to a batch reaction, the copolymer polymerization time is long (about 120 minutes), which is very uneconomical in terms of commercial production. .

The prior art (US4139690) of preparing a S-SBR binary copolymer using a metal organic compound containing a sulfonyl group (-SO ₃ ) was also preceded, but the dissolution characteristics of the alkoxide compound used in the organic solvent were poor. There is a limit to the application to commercial production in a batch reaction because of the risk of fire and the conversion of monomers during polymerization. In addition, when the amount of the alkoxide compound used in the above technology is above the limit, it becomes a factor that inhibits the polymerization reaction, and there is a difficulty in controlling the polymerization.

It is known that the ion exchange reaction between the anion of free lithium used as a polymerization catalyst and the metal present in the metal alkoxide is preceded first when the metal alkoxide compound is used as a randomizing agent in anionic polymerization (Macromo. Chem phys. 200, 2015- 2021 (1999). In the polymerization reaction, the polymerization of the monomer proceeds by the alkoxide metal ion formed after the ion exchange reaction. In general, the intermetallic ion exchange reaction tends to significantly slow down the exchange reaction rate at low temperature or room temperature. In order to increase the initiation reaction must proceed at a high temperature.

In the case of the metal alkoxide compound mentioned in the prior art, it does not dissolve well in organic solvents, which implies chemical handling problems and risks of fire. In particular, inexpensive alcohol is produced by reacting with water in a steam stripping process. Since it is azeotropic at the boiling point with the organic solvent, it is not separated from the organic solvent in the organic solvent refining process and includes a serious problem that alcohol is contained in the polymerized organic solvent, so its use is limited.

When preparing a copolymer in a batch reaction, a coupling coupling reaction is generally performed at the end of the polymerization. The purpose of the coupling reaction is to reduce the cold flow and to reduce the cold flow to increase the room temperature storage stability of the copolymer. This is to increase the pattern viscosity without significantly increasing the solution viscosity. At this time, as the coupling agent, tin tetrachloride, silicon tetrachloride compounds are generally used. In particular, recently, in order to increase affinity with silica, a technique using a polyvalent (hexavalent) polysiloxane coupling agent having superior hydrophilicity to existing coupling agents has been developed (US 6,846,873).

When attempting a coupling reaction using a polyvalent coupling agent for polymerization using a metal alkoxide compound used in the above-mentioned prior art as a randomizing agent, living by some metal alkoxide compound which is not dissolved in a solvent and does not react with a lithium catalyst The coupling reaction between the polymer and the coupling agent was disturbed and sufficient coupling efficiency could not be obtained.

Unlike the continuous polymerization, the batch reaction is carried out by adiabatic heating so that the initiation reaction should proceed at low temperature. This is because when the start temperature is high, the reactor temperature rises by 100 ° C. or more due to the heat of reaction, causing a safety problem. In this low initiation reaction, the ion exchange reaction between the lithium catalyst and the metal alkoxide metal proceeds very slowly, ultimately lowering the overall polymerization reaction rate, which is very disadvantageous in terms of economics, and due to the slow initiation reaction, the molecular weight distribution of the polymerized molecule is wide. This reduces the mechanical properties. In particular, as mentioned above, the coupling efficiency beyond the desired level cannot be obtained, which is disadvantageous for the production of high pattern viscosity rubber. For this reason, it is very limited to use a metal alkoxide compound introduced in the prior art as a randomizing agent in a batch polymerization reaction.

Accordingly, the inventors of the present invention have tried to solve the above problems, and as a result, cyclic oxoranyl alkane (cyclic) using an alkali metal alkoxide having excellent solubility in an organic solvent as a randomizing agent alone or an oligomer form as a vinyl content regulator Oxolanyl alkanes) is used as a catalyst and a series of processes for coupling a living polymer obtained by polymerizing a conjugated diene monomer and a vinylaromatic monomer in a hydrocarbon solvent in which an organolithium compound is present as a catalyst has been developed. The present invention has been completed.

According to the present invention, it is possible to solve the problems caused by using a conventional metal alkoxide compound in a batch polymerization, and even in a batch polymerization reaction, a specific alkali metal alkoxide used in the present invention may be used alone or in the form of an cyclic oxoranyl alkane of oligomer form (cyclic Oxolanyl alkanes) can be used in combination with a compound to produce a living polymer, control the vinyl content to a desired level, and the polymerization rate can be controlled similarly to the conventional batch polymerization.

In addition, when the living polymer is subjected to the coupling reaction by the method described in the present invention, a coupling number of about 0.5 to 1.5 higher than that of the conventional batch polymerization can be obtained. This is because the coupling agent used in the present invention is determined to solve the problem that it is difficult to bind all living polymers to the number of the number of bonds contained in the coupling agent by the molecular steric hindrance in the conventional case, Because of this, it is possible to produce a polymer of high physical properties at a low solution viscosity compared to the prior art, it is possible to economically produce a polymer with a higher pattern viscosity than a rubber that can be produced by the conventional batch polymerization method.

By carrying out the batch polymerization reaction using the alkali metal alkoxide, which is a solution form used in the present invention, as a randomizing agent, the solubility is higher in the organic solvent than the metal alkoxide introduced in the prior art, and the polymerization reaction is easily carried out with the organic lithium compound which is a polymerization catalyst. Participation, the coupling reaction of the living polymer thus obtained does not inhibit the coupling reaction to obtain a desired level of coupling efficiency, and since the boiling strip is generated in the steam stripping process, the organic solvent purification process It can be completely separated from organic solvents in order to solve the organic solvent contamination problem.

It is therefore an object of the present invention to provide an improved method for preparing a coupled vinylaromatic-conjugated diene random copolymer.

The present invention provides a process for preparing a living polymer by solution polymerization of a conjugated diene-based monomer and a vinylaromatic monomer in a hydrocarbon solvent in which an alkali metal alkoxide represented by the following Chemical Formula 1 and an organolithium compound are present as a randomizing agent, and the living polymer Next, a method for producing a coupled vinylaromatic-conjugated diene random copolymer comprising the step of coupling using a halide compound represented by Formula 2 or 3 as a coupling agent is characterized.

YCl ₄

(X) _a (R ₁ ) _b Y- [CH ₂ ] _c -Si (R ₂ ) (R ₃ )-[O-Si (R ₂ ) (R ₃ )] _d- [CH ₂ ] _c -Y ( X) _a (R ₁ ) _b

In Chemical Formulas 1 to 3, M is a metal element of Group 1 on the periodic table; X is a halogen atom selected from fluorine, chlorine, bromine and iodine; Y is Si or C; R ₁ is an alkyl group having 1 to 20 carbon atoms; R ₂ is selected from a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms substituted with halogen, and a silane group substituted with halogen; R ₃ is selected from a halogen atom selected from fluorine, chlorine, bromine, and iodine, a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms substituted with halogen, and a silane group substituted with halogen; a is 1-3, a + b = 3, c is 1-1000, d is 1-50000.

Hereinafter, the present invention will be described in detail.

The present invention uses a liquid alkali metal alkoxide having excellent solubility in an organic solvent as a randomizing agent alone, or a cyclic oxolanyl alkanes compound in an oligomer form as a vinyl content regulator, and these are used as catalysts. By coupling a living polymer obtained by polymerizing a conjugated diene monomer and a vinyl aromatic monomer in a hydrocarbon solvent in which a lithium compound is present with a polyvalent coupling agent, the vinyl content can be adjusted to a desired level, and Similarly, as the reaction rate is controlled, the coupling branch number and the coupling efficiency are controlled sufficiently high, and the reaction conversion ratio of the monomer is sufficiently high, so that the coupling shows the effect of commercial production of the random copolymer even in the batch polymerization. Vinylaromatic-conjugated diene random copolymer It relates to a manufacturing method of.

Hereinafter, a method for preparing the coupled vinylaromatic-conjugated diene random copolymer of the present invention will be described in detail for each process.

First, a process of preparing a living polymer by solution polymerization of a conjugated diene monomer and a vinyl aromatic monomer.

The conjugated diene monomer may be used one or a mixture thereof selected from 1,3-butadiene and isoprene, preferably 1,3-butadiene or isoprene.

The vinylaromatic monomer may be one selected from styrene and α-methyl styrene, or a mixture thereof, and preferably styrene or α-methyl styrene.

The monomer mixture used in the preparation of the vinylaromatic-conjugated diene random copolymer of the present invention comprises 50 to 95% by weight of the conjugated diene monomer and 5 to 50% by weight of the vinylaromatic monomer, preferably the conjugated diene monomer 10 It is preferable to use 45 to 45 weight% and 55 to 90 weight% of vinylaromatic monomers.

According to the present invention, since the polymerization is carried out to be complete, the proportion of monomers supplied is almost equal to the monomer bonding ratio in the resultant coupled vinylaromatic-conjugated diene copolymer. That is, the living polymer prepared by solution polymerization of the conjugated diene monomer and the vinyl aromatic monomer has a molar ratio of 50:50 to 95: 5 relative to the conjugated diene monomer.

 In the present invention, there is one feature of using a liquid specific alkali metal alkoxide as a randomizing agent for preparing the living polymer.

The alkali metal alkoxide has a structure as shown in the following formula (1), and has the characteristic of being present in the liquid phase in the organic solvent, which is a polymerization medium, by introducing this into the present invention to obtain a sufficient coupling efficiency with the random characteristics that could not be obtained by the conventional method It becomes possible.

[Formula 1]

In Formula 1, M is a group 1 metal on the periodic table, specifically lithium, sodium, potassium, cesium, rubidium, and the like, and more preferably potassium or sodium.

Such randomizing agents used in the present invention are specifically potassium-3,7-dimethyl-3-octanoside, sodium-3,7-dimethyl-3-octanoside, lithium-3,7-dimethyl- 3-octanoxide, cesium-3,7-dimethyl-3-octanoxide, rubidium-3,7-dimethyl-3-octanoside and the like can be selected and used, preferably potassium-3,7-dimethyl Preference is given to using -3-octanoxide and sodium-3,7-dimethyl-3-octanoside.

The randomizing agent may be used in an amount of 0.001 to 1.0 molar ratio, preferably 0.002 to 0.5 molar ratio per 1 mole of living polymer, and when the amount is less than the above range, the sufficient amount of the copolymer cannot be obtained. If exceeded, it is not preferable because it tends to inhibit the coupling reaction.

The present invention may further use a vinyl content regulator represented by the following formula (4) when the living polymer is prepared.

In Formula 4, R ′ and R ″ are the same or different and are an alkyl group having 1 to 20 carbon atoms.

The vinyl content regulator is a cyclic oxolanyl alkanes compound having a boiling point of 200 ° C. or higher, and thus, the organic content recovered in the steam stripping process is different from the conventional case by using such a vinyl content regulator. Solvent environmental pollution can be solved.

The vinyl content modifier is specifically, bis 2-oxolanyl methane, 2,2-bis (2-oxolanyl) propane (2,2-bis (2-oxolanyl) propane) , 1,1-bis (2-oxolanyl) ethane, 1,1-bis (2-oxolanyl) ethane, 2,2-bis (2-oxolanyl) butane (2,2-bis (2- oxolanyl) butane), 2,2-bis (5-methyl-2-oxolanyl) propane (2,2-bis (5-methyl-2-oxolanyl) propane), and 2,3-bis (3,4 , 5-trimethyl-2-oxoranyl) propane (2,2-bis (3,4,5-trimethyl-2-oxolanyl) propane), and 2,2-bis (2-tetrahydrofuranyl) propane ( 2,2-bis (2-tetrahydrofuranyl) propane) etc. may be used one or a mixture of two or more selected, preferably 2,2-bis (2-oxolaranyl) propane (2,2-bis (2-oxolanyl) propane) or 2,2-bis (2-tetrahydrofuranyl) propane (2,2-bis (2-tetrahydrofuranyl) propane) is preferably used.

The vinyl content regulator may be used in a molar ratio of 0.01 to 8.0 moles, preferably 0.02 to 5 moles per 1 mole of the living polymer, and if the amount is less than the above range, a sufficient vinyl content cannot be obtained. It is undesirable because it contains a part of me and tends to impair product quality (decrease in pattern viscosity and increase in volatile content).

In the solution polymerization of the present invention, the mixture of the conjugated diene monomer and the vinyl aromatic monomer is preferably 5 to 40% by weight in the hydrocarbon solvent, which is an organic solvent used in the polymerization medium, preferably 10 to 30% by weight, more preferably. It is carried out including 20 to 25% by weight.

The hydrocarbon solvent may be one or a mixture of two or more selected from aromatic hydrocarbons having 4 to 10 carbon atoms, paraffinic hydrocarbons, cycloparaffinic hydrocarbons, and the like. Specifically, n-pentane, iso-pentane, n-hexane, One or a mixture of two or more selected from n-heptane, iso-heptane, n-octane, iso-octane, cyclohexane, methylcyclopentane, benzene, toluene, xylene, ethylbenzene and the like may be used. Cyclohexane or n-heptane can be used. The hydrocarbon solvent will be liquid under polymerization conditions.

In the solution polymerization reaction of the conjugated diene monomer and the vinyl aromatic monomer, a mixture of the conjugated diene monomer and the vinyl aromatic monomer, a randomizing agent alone, or a vinyl content regulator may be added to the polymerization medium. When the reaction is completed, finally, the organolithium compound is added.

Typical polymerization initiation temperature is to be maintained in the range of 5 to 50 ℃, preferably 10 to 40 ℃. The pressure applied needs only to be sufficient for the conjugated diene monomer used to maintain the liquid phase. The polymerization proceeds until all of the monomers are converted into copolymers, in other words, the main reaction is carried out until a high conversion is achieved.

An organolithium compound is used as the catalyst used for the polymerization. The organolithium compound may be represented by the general formula R-Li (where R represents a hydrocarbyl radical having 1 to 20 carbon atoms, preferably 1 to 10 carbon atoms). Specifically, the organolithium compound is methyllithium, ethyllithium, isopropyllithium, n-butyllithium, secondary-butyllithium, n-octyllithium, tert-octyllithium, n-decyllithium, phenyllithium, 1- One or a mixture of two or more selected from naphthyllithium, 4-butylphenyllithium, p-tolyllithium, 4-phenyllithium, cyclohexylithium, 4-butylcyclohexylithium, and 4-cyclobutyllithium can be used. have.

The amount of the organolithium compound used for the polymerization is determined according to the target molecular weight of the copolymer to be synthesized, and the polymer molecular weight is inversely proportional to the amount of the catalyst. Molecular weight control is very important because the molecular weight of the polymer greatly affects the physical properties of the rubber, that is, the pattern viscosity. The organolithium compound may be used in the range of 0.01 to 8 molar ratio with respect to 1 mole of the living polymer, and preferably in the range of 0.05 to 5 molar ratio.

Next, the living polymer is a process of coupling using a halide compound represented by Formula 2 or 3 as a coupling agent.

That is, the terminal of the polymer is coupled using the halide compound at the completion of the reaction of the living polymer. The coupling agent used at this time uses a metal halide compound represented by the following formula (2) or (3).

[Formula 2]

YCl ₄

[Formula 3]

(X) _a (R ₁ ) _b Y- [CH ₂ ] _c -Si (R ₂ ) (R ₃ )-[O-Si (R ₂ ) (R ₃ )] _d- [CH ₂ ] _c -Y ( X) _a (R ₁ ) _b

In Formulas 2 to 3, X, Y, R ₁ , R ₂ , R ₃ , a, b, c, and d are as defined above.

That is, to use a halide compound or polyvalent polysiloxane compounds of 4 group elements on the periodic table as the coupling agent, preferably tin tetrachloride, silicon tetrachloride and polyvalent property (6 ⁺⁾ polysiloxane compound.

According to the present invention as described above, the vinyl content in the polymer can be adjusted to a desired level, and the polymerization reaction rate can be controlled similarly to the conventional batch polymerization.

In addition, according to the present invention, by carrying out a batch polymerization reaction using an alkali metal alkoxide in the form of a solution as a randomizing agent, its solubility in organic solvents is high so that it easily participates in the polymerization reaction with an organolithium compound which is a polymerization catalyst. The coupling reaction of the living polymer does not inhibit the coupling reaction, so that a desired level of coupling efficiency can be obtained, and alcohols having a high boiling point are generated in the steam stripping process, so that the organic solvent can be perfectly purified with the organic solvent. Separation can solve organic solvent contamination problem.

Hereinafter, the present invention will be described in detail with reference to Examples, but the present invention is not limited by the following Examples.

The following examples and comparative examples are a method for producing a random copolymer according to the present invention, the vinyl content of the prepared random copolymer, the block rate of the vinyl aromatic monomer, the microstructure of the conjugated diene, the molecular weight distribution of the copolymer, the bonded vinyl aromatic monomer The dispersion degree of is explained. In addition, the polymerization in the following examples and comparisons was carried out in a batch polymerization reaction using a 10 L autoclave reactor.

Example 1

In this example, vinylaromatic-conjugated diene copolymers are prepared using the techniques of the present invention in a batch reaction.

108 g (18% by weight) of styrene, 480 g (80% by weight) of 1, 3-butadiene and 3000 g of heptane were fed into a 10L reactor completely substituted with nitrogen and then sodium-3,7-dimethyl, a randomizing agent. 0.06 g of -3-octanoside (20 ppm in heptane) was fed to the reactor. When the supply is complete, the temperature inside the reactor is adjusted to 40 ° C. while the stirrer is turned on. When the temperature reaches the set temperature, 0.26 g of n-butyllithium is added to the reactor to proceed the polymerization reaction by adiabatic heating reaction. The degree was determined by observing the change in reaction temperature. A small amount of reactant was taken during the reaction to analyze monomer ratio and reaction conversion.

After the reaction temperature reached the maximum temperature (about 95 ° C.), 12 g (2 wt%) of 1,3-butadiene was fed to replace the polymer end with butadiene. When the addition of butadiene is completed, 0.45 g of α, ω-bis (2-trichlorosilylethyl) polydimethylsiloxane as a coupling agent is supplied to the reactor, and the mixture is left for a certain time to proceed with the coupling reaction. 1 g of BHT (2,6-di-tert -butyl-4-methylphenol) was added to the reactor as a terminator to terminate the reaction.

The polymer was poured into hot water heated with steam, stirred to remove the solvent, and then roll dried to remove the residual amount of solvent and water. The alcohol content in the recovered organic solvent was analyzed by GC analysis on the organic solvent recovered during the steam stripping. For the polymer, the microstructure of the molecule was analyzed using NMR, the molecular weight, the degree of coupling, the molecular weight distribution using the GPC, and the pattern viscosity using the pattern viscometer.

Example 2

In Example 2, a copolymerization reaction was carried out in a batch reactor in the same manner as in Example 1 using a randomizing agent and a vinyl content adjusting agent.

 108 g (18% by weight) of styrene, 480 g (80% by weight) of 1,3-butadiene and 3000 g of heptane were fed into a 10 L reactor, followed by 0.06 g of randomizing agent sodium-3,7-dimethyl-3-octanoside (in heptane). 20 ppm) and 0.15 g of 2,2-bis (2-oxoranyl) propane (hereinafter DTHFP) (50 ppm in heptane) were fed to the reactor. When the supply was completed, the reactor inside temperature was adjusted to 40 ° C. while turning the stirrer, and when the reactor temperature reached the set temperature, 0.26 g of n-butyllithium was added to the reactor to proceed with a polymerization reaction by adiabatic heating. The degree of polymerization was determined by observing the reaction temperature change, and a small amount of reactants were taken from the reaction to analyze the monomer ratio and the reaction conversion.

When the reaction temperature reached the maximum temperature, 12g (2% by weight) of 1,3-butadiene was supplied to replace the reaction terminal with butadiene. When the additional butadiene supply was completed, 0.45 g of the α, ω-bis (2-trichlorosilylethyl) polydimethylsiloxane as a coupling agent was supplied to the reactor, and the coupling reaction was performed by standing for a certain time. After completion of the coupling reaction, 1 g of BHT was added to the reactor as a reaction terminator to terminate the reaction.

Example  3

In Example 3, the same procedure as in Example 1 was conducted, but the coupling agent was replaced with 0.102 g of silicon tetrachloride to proceed with the reaction.

Comparative example  One

In Comparative Example 1, but proceeding in the same manner as in Example 1 using a conventional sodium pentoxide (STA) as a randomizing agent.

Comparative example  2

In the same manner as in Example 2, a randomizing agent used STA (sodium pentoxide).

Comparative example  3

In the same manner as in Example 3 and using a randomizing agent STA (sodium pentoxide).

Comparative example  4

In Comparative Example 3, the procedure was the same as in Example 2, but 12 g of THF (4000 ppm in heptane) was used as a vinyl content regulator.

Comparative example  5

In Comparative Example 5 was carried out in the same manner as in Example 2, but 0.15 g of tetramethyl ethylene diamine (TMEDA) (50 ppm in haptan) was used as a vinyl content regulator.

Comparative example  6

In Comparative Example 6, the procedure was the same as in Example 3, but 0.15 g of tetramethyl ethylene diamine (TMEDA) (50 ppm in haptan) was used as a vinyl content regulator.

Example  4

In Example 4, a copolymer having a styrene content of 30% by weight in a batch reaction was prepared.

180 g (30% by weight) of styrene, 408g (68% by weight) of 1,3-butadiene and 3000g of heptane were fed into a 10L reactor, followed by 0.108g of sodium-3,7-dimethyl-3-octanoside, a randomizing agent (in heptane). 30 ppm) was fed to the reactor. When the supply was completed, the temperature inside the reactor was adjusted to 30 ° C. while turning the stirrer, and when the reactor temperature reached the set temperature, 0.26 g of n-butyllithium was added to the reactor to proceed with a polymerization reaction by adiabatic heating. The degree of polymerization was determined by observing the reaction temperature change, and a small amount of reactants were taken from the reaction to analyze the monomer ratio and the reaction conversion.

When the reaction temperature reached the maximum temperature, 12 g (2% wt.%) Of 1,3-butadiene was supplied to replace the reaction terminal with butadiene. When the additional butadiene feed was completed, 0.45 g of a coupling agent, α, ω-bis (2-trichlorosilylethyl) polydimethylsiloxane, was fed to the reactor and allowed to stand for a predetermined time to proceed with the coupling reaction. After the coupling reaction, the reaction was terminated by adding 1 g of BHT as a reaction terminator into the reactor.

Example  5

In Example 5, polymerization was carried out under the same conditions as in Example 4, but the reaction was carried out by mixing and adding 0.18 g (50 ppm in heptane) of 2,2-bis (2-oxoranyl) propane (DTHFP) as a vinyl content regulator. .

Example  6

In this example, the same procedure as in Example 4 was carried out, but the coupling agent was replaced with 0.102 g of silicon tetrachloride to proceed with the reaction.

Comparative example  7

In Comparative Example 7, the same procedure as in Example 4 was performed, but the randomizing agent was changed to STA (sodium pentoxide).

Comparative example  8

In Comparative Example 8, the same procedure as in Example 6 was carried out, but the randomizing agent was used as sodium pentoxide (STA).

Comparative example  9

In Comparative Example 9, the same procedure as in Example 6 was carried out, but THF (4000 ppm in heptane) was used as a vinyl content regulator.

Comparative example  10

In Comparative Example 10, the same procedure as in Example 5 was carried out, but a randomizing agent was used as sodium pentoxide (STA) and a vinyl content regulator was used as TMEDA (50 ppm in heptane).

Comparative example  11

In Comparative Example 11, the same procedure as in Example 6 was conducted, except that the randomizing agent was STA (sodium pentoxide), the vinyl content regulator was TMEDA (50 ppm in heptane), and the coupling agent was α, ω-bis (2-trichlorosilylethyl) poly. 0.45 g of dimethylsiloxane was used.

Comparative example  12

In Comparative Example 11 was carried out in the same manner as in Example 6, using a randomizing agent (STA) (sodium pentoxide), the vinyl content regulator TMEDA (50ppm in heptane).

The conditions of Examples 1 to 6 and Comparative Examples 1 to 12 are summarized in Table 1 below.

Experimental Example

The polymers prepared in Examples 1 to 6 and Comparative Examples 1 to 12 were analyzed for random and block ratios of conjugated diene compounds and aromatic vinyl compounds and vinyl structure contents of conjugated dienes using NMR (nuclear magnetic resonance), Molecular weight, molecular weight distribution (MWD), coupling rate (C / E), and coupling index (C / N) were analyzed using GPC (Gel permeation chromatography), and the pattern viscosity was measured using a pattern viscosity measuring instrument. The results of the analysis of the polymers according to Examples 1 to 6 and Comparative Examples 1 to 12 carried out by the above method are summarized in Table 2 below. In addition, the results of gas chromatogram (GC) analysis of the recovered organic solvent after steam stripping are shown in Table 3 below.

As shown in Table 2, according to the present invention, a coupling number of about 0.5 to 1.5 higher than the coupling number obtained in a conventional batch polymerization reaction can be obtained, which is characteristic of the present invention. In the conventional case, it is determined that the living polymer is difficult to bind to the number of the branches of the coupling agent due to molecular steric hindrance.

In addition, according to the present invention, it is possible to produce a polymer of high physical properties at a low solution viscosity, it is possible to economically produce a polymer with a higher pattern viscosity than a rubber that can be produced by the conventional batch polymerization method.

According to Table 3, in the case of the present invention it can be seen that the alcohol and vinyl content regulator is not detected in the organic solvent recovered by steam stripping.

As described above, in the batch polymerization, the use of a metal alkoxide compound as a randomizing agent enables the production and commercial application of binary copolymers with the same reaction characteristics and the same productivity as the conventional batch polymerization, and facilitates the coupling efficiency of the coupling agent. It is possible to control, and it is possible to produce a copolymer having a higher coupling number than the coupling copolymer produced by the conventional batch polymerization technique.

In addition, the functional group ratio can be controlled in the same manner as the conventional batch polymerization technique when introducing functional groups.

With the technology of the present invention, it is possible to solve a problem of reducing coupling efficiency generated when applying a metal alkoxide compound to a batch polymerization, a problem of contamination of a purified organic solvent, a problem of lowering mechanical properties due to an increase in molecular weight distribution, a problem of delaying a reaction time, and the like.

Claims (13)

A process of preparing a living polymer by solution polymerization of an alkoxide of an alkali metal represented by the following Chemical Formula 1 as a randomizing agent and a hydrocarbon solvent in which an organolithium compound is present and a conjugated diene monomer and a vinylaromatic monomer; A method of preparing a coupled vinylaromatic-conjugated diene random copolymer comprising the step of coupling the living polymer using a halide compound represented by Formula 2 or 3 as a coupling agent; [Formula 1]

[Formula 2] YCl ₄ [Formula 3] (X) _a (R ₁ ) _b Y- [CH ₂ ] _c -Si (R ₂ ) (R ₃ )-[O-Si (R ₂ ) (R ₃ )] _d- [CH ₂ ] _c -Y ( X) _a (R ₁ ) _b In Chemical Formulas 1 to 3, M is a metal element of Group 1 on the periodic table; X is a halogen atom selected from fluorine, chlorine, bromine and iodine; Y is Si or C; R ₁ is an alkyl group having 1 to 20 carbon atoms; R ₂ is selected from a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms substituted with halogen, and a silane group substituted with halogen; R ₃ is selected from a halogen atom selected from fluorine, chlorine, bromine, and iodine, a hydrogen atom, an alkyl group having 1 to 20 carbon atoms, an alkyl group having 1 to 20 carbon atoms substituted with halogen, and a silane group substituted with halogen; a is 1-3, a + b = 3, c is 1-1000, d is 1-50000. The method of claim 1, wherein the manufacturing method of the copolymer, characterized in that for adding the vinyl content regulator represented by the following formula (4) when the living polymer is prepared; [Formula 4]

In Formula 4, R ′ and R ″ are the same or different and are an alkyl group having 1 to 20 carbon atoms. The method of claim 1, wherein the randomizing agent is used in an amount of 0.001 to 1.0 mole ratio with respect to 1 mole of living polymer. The method of claim 1, wherein the randomizing agent is potassium-3,7-dimethyl-3-octanoside, sodium-3,7-dimethyl-3-octanoside, lithium-3,7-dimethyl-3-octanoxoxide. A method for producing a copolymer, characterized in that one or a mixture of two or more selected from the side, cesium-3,7-dimethyl-3-octanoside, and rubidium-3,7-dimethyl-3-octanoside. 3. The method of claim 2, wherein the vinyl content modifier is 2,2-bis (2-tetrahydrofuranyl) propane. The method of claim 1, wherein the conjugated diene monomer is 1,3-butadiene and isoprene. The method according to claim 1, wherein the vinylaromatic monomer is styrene and alpha methyl styrene. The method according to claim 1, wherein the living polymer has a molar ratio of 50:50 to 95: 5 of the vinylaromatic monomer to the conjugated diene monomer. The method according to claim 1, wherein the organolithium compound is contained in an amount of 0.01 to 8 moles per 1 mole of the living polymer. The method according to claim 1, wherein the hydrocarbon solvent is one or a mixture of two or more selected from aromatic hydrocarbons having 4 to 10 carbon atoms, paraffinic hydrocarbons, and cycloparaffinic hydrocarbons. The method of claim 1, wherein the hydrocarbon solvent is n-pentane, iso-pentane, n-hexane, n-heptane, iso-heptane, n-octane, iso-octane, cyclohexane, methylcyclopentane, benzene, toluene, xylene , And one or two or more mixtures selected from ethylbenzene. The method of claim 1, wherein the living polymer in the hydrocarbon solvent is included in the range of 5 to 40% by weight. The method of claim 1, wherein the coupled vinylaromatic-conjugated diene random copolymer has a Mooney viscosity (ML1 + 4, 100 ℃) of 20 to 200, the vinyl group content of the conjugated diene region of 10 to 90% by weight. Method for producing a copolymer characterized in that.