KR101683334B1 - Method for preparing vinyl aromatic hydrocarbon-conjugated diene copolymer - Google Patents

Abstract

The present invention provides a process for producing a polymer comprising the steps of: a) conducting a polymerization reaction with a conjugated diene monomer or a conjugated diene monomer and a vinyl aromatic monomer in the presence of an anionic polymerization initiator in a nonpolar solvent to form an active polymer having an active terminal; And b) a step of reacting the active polymer with a modifier and then introducing an anion polymerization initiator having a lower activity value than that of the anion polymerization initiator in step a). will be.

Description

METHOD FOR PREPARING VINYL AROMATIC HYDROCARBON-CONJUGATED DIENE COPOLYMER BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vinyl aromatic hydrocarbon-

The present invention relates to a process for producing a vinyl aromatic hydrocarbon-conjugated diene copolymer, and more particularly, to a process for producing a vinyl aromatic hydrocarbon-conjugated diene copolymer improved in coupling reaction using a metal amide initiator, To a vinyl aromatic hydrocarbon-conjugated diene copolymer produced.

Generally, conjugated diene polymers such as styrene-butadiene rubber (SBR) or butadiene rubber (BR) are prepared by emulsion polymerization or solution polymerization.

The biggest advantage of the solution polymerization in the production of SBR or BR in comparison with the emulsion polymerization is that the vinyl structure content and the styrene content which regulate the rubber properties can be arbitrarily controlled and the molecular weight and physical properties Can be adjusted.

Therefore, solution-polymerized SBR or BR has been widely used as a rubber material for tire treads because it can easily change its structure and can reduce the movement of chain ends due to bonding or modification of chain ends and increase bonding force with carbon black.

When such a solution-polymerized SBR is used as a rubber material for a tire tread, it is possible to increase the glass content of the rubber by increasing the vinyl content in the copolymer, thereby controlling the running resistance, braking force and tire required properties, .

Anion solution polymerization during solution polymerization has a characteristic that macromolecules can be produced by reacting a silane or a conjugate having a polyfunctional group on the active terminal of the polymer.

The copolymer produced by anion solution polymerization can control its properties by controlling the number of bonds of polyfunctional groups. Conventionally, a method of adjusting the number of polyfunctional groups by controlling the molar ratio of the polyfunctional groups has been used. However, since the number of bonds of polyfunctional groups is controlled by the molar ratio of the conjugate, there is a problem that it is not easy to change the amount.

KR 2013-0059441 A KR 2007-0117626 A

An object of the present invention is to provide a process for producing a vinyl aromatic hydrocarbon-conjugated diene copolymer capable of increasing the efficiency of the coupling reaction between the active terminal of a polymer and a modifier in anion solution polymerization.

It is another object of the present invention to provide a vinyl aromatic hydrocarbon-conjugated diene copolymer produced by the process for producing the vinyl aromatic hydrocarbon-conjugated diene-based copolymer.

In order to achieve the above object, the present invention provides a process for producing a polymer, comprising the steps of: a) conducting a polymerization reaction with a conjugated diene monomer or conjugated diene monomer and a vinyl aromatic monomer in the presence of an anionic polymerization initiator in a nonpolar solvent to form an active polymer having an active terminal ; And b) a step of reacting the active polymer with a modifier and then introducing an anion polymerization initiator having a lower activity value than that of the anion polymerization initiator in step a). do.

Further, the present invention provides a vinyl aromatic hydrocarbon-conjugated diene copolymer produced by the above-mentioned production method.

According to the present invention, macromolecules can be efficiently produced by increasing the efficiency of the binding reaction between the active terminal of the polymer and the modifier in anion solution polymerization.

According to the present invention, a vinyl aromatic hydrocarbon-conjugated diene copolymer excellent in workability can be produced and used in a rubber composition for a tire.

Hereinafter, the present invention will be described in detail.

The process for producing a vinyl aromatic hydrocarbon-conjugated diene-based copolymer of the present invention comprises the steps of: a) carrying out a polymerization reaction of a conjugated diene monomer or conjugated diene monomer and a vinyl aromatic monomer in the presence of an anionic polymerization initiator in a nonpolar solvent, Forming an active polymer; And b) a step of reacting the active polymer with a modifier and then adding an anion polymerization initiator having a lower activity value than that of the anion polymerization initiator in the step a).

Examples of the conjugated diene monomer include 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 2-methyl-1,3-hexadiene, piperylene, 3-butyl-1,3-octadiene, isoprene, Butadiene, and the like.

The amount of the conjugated diene monomer may be, for example, 50 to 95% by weight, more preferably 55 to 90% by weight, and most preferably 65 to 85% by weight based on 100% by weight of total monomers.

Examples of the vinyl aromatic monomer include styrene,? -Methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylene styrene, 1-vinylnaphthalene, 2-vinylnaphthalene, 1- 4-cyclohexylstyrene, 4- (p-methylphenyl) styrene, 1-vinyl-5-hexylnaphthalene, vinyltoluene, 3,5-diethylstyrene, 2- -Phenylstyrene, 4-p-trilstyrene, and 4,5-dimethyl-1-vinylnaphthalene.

The content of the vinyl aromatic monomer may be, for example, 5 to 50% by weight, 10 to 45% by weight or 15 to 35% by weight based on 100% by weight of total monomers.

The non-polar solvent may be, for example, a hydrocarbon solvent.

The hydrocarbon solvent may be at least one selected from the group consisting of n-pentane, n-hexane, n-heptane, isooctane, cyclohexane, toluene, benzene and xylene.

The amount of the non-polar solvent may be, for example, 50 to 800 parts by weight, 100 to 700 parts by weight, or 400 to 600 parts by weight based on 100 parts by weight of the total amount of the monomers.

The anion polymerization initiator in step a) is preferably an organic lithium compound.

The organolithium is preferably selected from the group consisting of methyllithium, ethyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, n-decyllithium, tert- octyllithium, phenyllithium, Eicosyllithium, 4-butylphenyllithium, 4-tolylithium, cyclohexyllithium, 3,5-di-n-heptylcyclohexyllithium and 4-cyclopentyllithium.

The amount of the anionic polymerization initiator may be 0.01 to 10 mmol, 0.05 to 5 mmol, 0.3 to 5 mmol, 0.1 to 2 mmol, or 0.15 to 0.8 mmol based on 100 g of the total monomer.

For example, the step a) may be a step of mixing the vinyl aromatic monomer, the conjugated diene monomer and the non-polar solvent, raising the temperature, and then adding an anionic polymerization initiator to proceed the polymerization reaction.

The polymerization in a) may be a living anionic polymerization in which an active terminal is obtained by a growth reaction with an anion.

Further, the polymerization in a) may be a temperature-raising polymerization. The temperature-raising polymerization refers to a polymerization method comprising a step of increasing the reaction temperature by optionally applying heat after the polymerization initiator is added. Preferably, the polymerization is an adiabatic heating reaction.

For example, the anion polymerization initiator may be introduced after the internal temperature of the reactor or the temperature of the mixture is raised to 40 to 80 캜, more preferably 50 to 70 캜, and most preferably 55 to 65 캜.

As a result of step (a), an active polymer having an active terminal is formed. The active polymer having an active terminal means a polymer in which the termination reaction does not occur but the activity of the growth end remains intact.

The modifier may be a compound having a polyfunctional group such as silane, epoxy or alkoxy group. The modifier may be a conjugate that is reactive with the active terminal of the active polymer.

The amount of the modifier may be, for example, 0.01 to 10 mmol, 0.05 to 5 mmol, 0.3 to 5 mmol, 0.1 to 2 mmol, or 0.15 to 0.8 mmol based on 100 g of the total polymer.

The modifier is introduced after the polymerization temperature reaches a peak as a result of the polymerization reaction in the step a). The polymerization temperature is, for example, from 0 to 100 ° C, preferably from 20 to 80 ° C. In this range, the reaction rate is high and the reaction temperature is economical, the temperature of the reactor is easily controlled, the solution viscosity is not rapidly increased, It is effective. Therefore, it is preferable that the peak of the polymerization temperature is determined within the above range.

The inventors of the present invention confirmed that when the active terminal of the active polymer is conjugated with the modifier, the efficiency of the conjugation reaction can be increased by adding an anionic initiator having lower activity than the anion polymerization initiator used in the polymerization.

It is preferable that the activity value of the anion polymerization initiator of the step b) is lower than the activity value of the anion polymerization initiator of the step a). Preferable examples thereof include metal amide compounds such as lithium amide.

The amount of the anion polymerization initiator added in step b) is preferably 0.05 to 2 times, more preferably 0.1 to 1 times the amount of the anion polymerization initiator in step a).

The anionic polymerization initiator in step b) is added within 1 to 10 minutes, more preferably within 1 to 5 minutes after the addition of the modifier.

The method for producing the vinyl aromatic hydrocarbon-conjugated diene copolymer according to the present invention is characterized in that the efficiency of the coupling reaction is increased to 40% or more by further adding an anionic polymerization initiator within 1 to 10 minutes after the addition of the modifier in the step b) Can be increased.

The step b) is carried out at 0 to 90 ° C for 1 minute to 5 hours.

The vinyl aromatic hydrocarbon-conjugated diene-based copolymer of the present invention can be produced, for example, by further adding a polar additive to the polymerization reaction in step a).

The polar additive may be, for example, a base, and another example may be an ether, an amine, or a mixture thereof.

As another example, the polar additive may be selected from the group consisting of trimethylamine, triethylamine, N, N ', N'-tetramethylethylendiamine (TMEDA), diethyl ether, Di-n-propyl ether, diisopropyl ether, di-n-butyl ether, tetrahydrofuran, dioxane, ethylene glycol dimethyl ether ethylene glycol dimethyl ether, ethylene glycol diethyl ether, triethylene glycol dimethyl ether, N-methyl morpholine, N-ethylmorpholine ), N-methallyl morpholin, and ditetrahydrofurylpropane (DTHFP).

The polar additive may be, for example, 0.06 to 60 mmol, 0.3 to 30 mmol, 0.6 to 12 mmol, or 0.9 to 5 mmol based on 100 parts by weight of total monomers.

As another example, the polar additive may be 0.1 to 40 mol or 0.1 to 10 mol based on 1 mol of the anionic polymerization initiator.

When a conjugated diene monomer and a vinyl aromatic monomer are copolymerized, a block copolymer is likely to be produced due to the difference in the reaction rate thereof. However, when the polar additive is added, the reaction rate of a vinyl aromatic compound having a slow reaction rate is increased, For example, a random copolymer of the copolymer.

The molar ratio of the anionic polymerization initiator to the polar additive may be, for example, 1: 1 to 1:20, 1: 2 to 1:10, or 1: 4 to 1: 8.

The production method of the present invention may include a step of adding a polymerization reaction bed to terminate the reaction.

The polymerization reaction may be, for example, water or alcohol.

The polymerization reaction may be, for example, a reaction pressure of 1 to 10 kgf / cm ² .

The vinyl aromatic hydrocarbon-conjugated diene-based copolymer of the present invention can be produced, for example, by a batch polymerization method or a continuous polymerization method including one or two or more reactors.

The vinyl aromatic hydrocarbon-conjugated diene-based copolymer of the present invention can be produced, for example, by a batch polymerization method or a continuous polymerization method including one or two or more reactors.

The present invention provides a vinyl aromatic hydrocarbon-conjugated diene copolymer produced by the above-described process for producing a vinyl aromatic hydrocarbon-conjugated diene-based copolymer.

The vinyl aromatic hydrocarbon-conjugated diene-based copolymer of the present invention is characterized in that it is produced by the above production method.

The vinyl aromatic hydrocarbon-conjugated diene copolymer of the present invention is characterized in that the vinyl aromatic monomer is contained in an amount of 5 to 50% by weight and the vinyl content is 35 to 55% by weight.

The vinyl aromatic monomer may preferably be 10 to 45% by weight, more preferably 15 to 35% by weight.

The vinyl content may preferably be 40 to 55% by weight, more preferably 40 to 50% by weight.

In the present invention, the vinyl content refers to the content of the conjugated diene-based monomer forming the vinyl group based on 100 wt% of the total of the monomers.

The vinyl aromatic hydrocarbon-conjugated diene copolymer may have a weight average molecular weight (Mw) of 50,000 to 600,000 g / mol, more preferably 80,000 to 500,000 g / mol, and most preferably 100,000 to 400,000 g / mol. have.

The vinyl aromatic hydrocarbon-conjugated diene-based copolymer may have a number average molecular weight (Mn) of 50,000 to 600,000 g / mol, more preferably 80,000 to 500,000 g / mol, and most preferably 100,000 to 400,000 g / mol. have.

For example, the vinyl aromatic hydrocarbon-conjugated diene copolymer may have a molecular weight distribution (PDI) of 1.05 to 2.0, more preferably 1.1 to 1.9, and most preferably 1.2 to 1.8.

The vinyl aromatic hydrocarbon-conjugated diene-based copolymer may be, for example, a random copolymer.

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope and spirit of the invention as disclosed in the accompanying claims. Changes and modifications may fall within the scope of the appended claims.

[Example]

Example  One

120 g of styrene, 312 g of 1,3-butadiene, 2200 g of n-hexane and 0.4 g of ditetrahydrofuryl propane were placed in a 6 L polymerization reactor, and the temperature inside the reactor was adjusted to 40 캜 with stirring while stirring. When the temperature reached 40 캜, an n-butyllithium initiator was added to the reactor to proceed the adiabatic reaction. 5 minutes after the polymerization temperature reached the peak, 8 g of butadiene was added, and 5 minutes later, the modifier was added. After 5 minutes, the lithium amide initiator (0.22 g, 0.3 times the polymerization initiator) After stopping the reaction using methanol, the reaction was terminated by adding wingstay K (15 ml) as an antioxidant to obtain a polymer.

The polymer was put into hot water heated with steam and stirred to remove the solvent. The solvent was then removed by roll drying to remove residual solvent and water to prepare a styrene-butadiene copolymer.

Example  2

Except that the styrene-butadiene copolymer (SBR) was prepared in the same manner as in Example 1 except that the lithium amide initiator was added two minutes after the addition of the modifier.

Example  3

SBR was prepared in the same manner as in Example 2, except that the amount of the lithium amide initiator was added at one time as compared with the polymerization initiator.

Example  4

SBR was prepared in the same manner as in Example 3 except that the amount of the lithium amide initiator was 0.1 times the amount of the polymerization initiator.

Comparative Example  One

SBR was prepared in the same manner as in Example 1 except that the lithium amide initiator was not charged after the addition of the modifier.

Comparative Example  2

SBR was prepared in the same manner as in Example 1 except that the lithium amide initiator was added 5 minutes prior to the addition of the modifier.

Comparative Example  3

SBR was prepared in the same manner as in Example 4 except that the lithium amide initiator was added two minutes prior to the addition of the modifier.

The characteristics of the styrene-butadiene copolymers prepared in Examples 1 to 4 and Comparative Examples 1 and 2 were analyzed and the results are shown in Table 1 below. The weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (PDI) were measured by GPC analysis under the condition of 40 占 폚. In this case, two columns of PLgel Olexis column manufactured by Polymer Laboratories were combined with one column of PLgel mixed-C column, and all of the new columns were of mixed bed type. Also, PS (Polystyrene) was used as a GPC reference material in molecular weight calculation.

Polymerization batch GPC Mp1
(x 10 ³ ) Mp2
(x 10 ³ ) Mn
(x 10 ³ ) Mw
(x 10 ³ ) Coupling Efficiency (%) PDI Example 1 258 547 337 442 52.5 1.31 Example 2 246 514 317 403 49.8 1.27 Example 3 248 511 322 410 51.1 1.27 Example 4 253 544 334 431 50.8 1.29 Comparative Example 1 308 651 358 467 39.2 1.30 Comparative Example 2 267 575 318 406 38.4 1.28

As shown in Table 1, the styrene-butadiene copolymers of Examples 1 to 4, in which the lithium amide initiator was added and added after the addition of the modifier, were styrene-butadiene copolymer of Comparative Example 1 in which no lithium amide initiator was added, It was confirmed that the lithium amide initiator exhibited a higher bonding ratio as compared with the styrene-butadiene copolymer of Comparative Example 2, which was previously charged before the modifier was added.

Claims (15)

a) conducting a polymerization reaction with a conjugated diene-based monomer or a conjugated diene-based monomer and a vinyl aromatic monomer using an anionic polymerization initiator in a nonpolar solvent to form an active polymer having an active terminal; And
b) reacting said active polymer with a modifier and then introducing an amide initiator. < RTI ID = 0.0 > 11. < / RTI > [4] The method according to claim 1, wherein the content of the conjugated diene monomer is 50 to 95% by weight based on 100% by weight of the total monomers. The vinyl aromatic hydrocarbon-conjugated diene copolymer according to claim 1, wherein the content of the vinyl aromatic monomer is 5 to 50 wt% based on 100 wt% of the total monomers. The method for producing a vinyl aromatic hydrocarbon-conjugated diene copolymer according to claim 1, wherein the amount of the non-polar solvent is 50 to 800 parts by weight based on 100 parts by weight of the total amount of the monomers. The anion polymerization initiator of claim 1, wherein the anion polymerization initiator in step a) is an organolithium compound selected from the group consisting of methyllithium, ethyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, tert- Octyl lithium, phenyl lithium, 1-naphthyl lithium, n-eicosyl lithium, 4-butylphenyl lithium, 4-tolyl lithium, cyclohexyl lithium, 3,5- Pentyl lithium, and mixtures thereof. 2. The vinyl aromatic hydrocarbon-conjugated diene-based copolymer according to claim 1, wherein the vinyl aromatic hydrocarbon-conjugated diene copolymer is at least one selected from the group consisting of ethylene, propylene, [Claim 2] The method according to claim 1, wherein the content of the anionic polymerization initiator in step a) is 0.01 to 10 mmol based on 100 g of the total monomers. [2] The method of claim 1, wherein the step a) comprises mixing the vinyl aromatic monomer, the conjugated diene monomer and the nonpolar solvent, raising the internal temperature of the reactor or the temperature of the mixture to 40 to 80 ° C, Wherein the vinyl aromatic hydrocarbon-conjugated diene-based copolymer is a copolymer of vinyl aromatic hydrocarbon and conjugated diene copolymer. The method for producing a vinyl aromatic hydrocarbon-conjugated diene-based copolymer according to claim 1, wherein the modifier is a compound having silane, epoxy or alkoxy group. The method for producing a vinyl aromatic hydrocarbon-conjugated diene-based copolymer according to claim 1, wherein the content of the modifier is 0.01 to 10 mmol based on 100 g of the polymer. The method for producing a vinyl aromatic hydrocarbon-conjugated diene-based copolymer according to claim 1, wherein the activity of the amide initiator in step b) is lower than the activity of the anion polymerization initiator in step a). The method for producing a vinyl aromatic hydrocarbon-conjugated diene-based copolymer according to claim 1, wherein the amount of the amide initiator in step b) is 0.05 to 2 times the amount of the anion polymerization initiator in step a). [Claim 2] The method according to claim 1, wherein the amide initiator in step b) is introduced within 1 to 10 minutes after the addition of the modifier. [Claim 3] The method according to claim 1, wherein the coupling efficiency of the step b) is 40% or more. [Claim 6] The method according to claim 1, wherein the method further comprises adding a polar additive to the polymerization reaction in step a) to polymerize the vinyl aromatic hydrocarbon-conjugated diene copolymer. delete