Methods of manufacturing conjugated diene-based polymers, and polymers, rubbers, and tires made therefrom

Abstract

To provide a method for producing a conjugated diene-based polymer by which rubber having significantly superior rolling resistance, the product of tensile strength at break and elongation strength at break, tear strength, and rigidity can be obtained.SOLUTION: The present invention relates to a method for producing conjugated diene-based polymers. The conjugated diene-based polymers are obtained by polymerizing conjugated diene monomers or conjugated diene monomers and vinyl aromatic monomers using an initiator. Here, the initiator is obtained by reacting a divinylarene-like compound represented by a formula (1) with an organic alkali metal. In the formula, A and B are CnH2n+1 or an aromatic ring, n is 0 to 5, A and B may be the same or different, and Q is an aromatic ring; the molar ratio of the divinylarene-like compound to the effective active organic alkali metal is 1.3 to 5.0. The present invention further relates to rubber comprising the conjugated diene-based polymers, and a tire comprising the rubber.SELECTED DRAWING: None

Description

Technical Field

[0001] The present invention relates to a method for producing a conjugated diene polymer, the polymer, rubber containing the conjugated diene polymer, and a tire containing the rubber.

Background Art

[0002] Solution styrene-butadiene rubber (SSBR) is a conjugated diene polymer composed of butadiene monomer and styrene monomer. The batch process for producing SSBR was first proposed by Phillips Company (USA), and the continuous process for producing SSBR was proposed by Firestone Tire and Rubber Company, leading industrial production. Since SSBR is superior to emulsion styrene-butadiene rubber (ESBR) in mechanical properties and rolling resistance, it can be widely used in the automotive industry or other rubber products. In order to further improve the properties of rubber materials, the industry has been continuously working on improving the properties of conjugated diene polymers.

[0003] US8946339B2 and EP2338919B1 provide a modified conjugated diene polymer having a silyl group substituted with one or more alkoxy groups and one or more nitrogen atoms at the chain ends of the conjugated diene polymer. The modified conjugated diene polymer is obtained by reacting a living polymer end of a conjugated diene polymer with a compound having a silyl group substituted with two or more alkoxy groups and one or more nitrogen atoms. The conjugated diene polymer is obtained by polymerizing a conjugated diene compound or copolymerizing a conjugated diene compound and an aromatic vinyl compound using a polyfunctional anionic polymerization initiator. The polyfunctional anionic polymerization initiator is prepared from a polyvinyl aromatic compound and an organolithium compound at a molar ratio (meaning polyvinyl aromatic compound / organolithium compound) in the range of 0.05 to 1.0.

[0004] US6221975B1 provides a method for preparing a random copolymer functionalized at both ends. Such a method includes synthesizing a random copolymer derived from an aromatic vinyl monomer and a conjugated diene monomer at only one of the two anionic ends of a polyfunctional organic lithium initiator in the presence of a nonpolar hydrocarbon solvent; then adding a polar additive and an electrophilic material to the living polymer to obtain a random copolymer functionalized at both ends.

[0005] US6455651 provides a method for anionic polymerization of monomers, which includes contacting the monomers with a functional anionic polymerization initiator (an organosubstituted alkali metal compound). This improvement includes adding 0.1 to 1.0 equivalents of a metal alkyl compound per equivalent of the alkali metal compound, and the alkyl group of the metal alkyl compound is selected so as not to exchange with the organic substituent of the alkali metal compound. The organic substituent of the alkali metal compound is aliphatic, alicyclic, aromatic, or alkyl-substituted aromatic.

[0006] US6562923 provides a method for preparing a dilithiated initiator useful for anionic polymerization. Here, such a method includes reacting a dialkenylbenzene having two double bonds with secondary butyllithium in an aliphatic or alicyclic hydrocarbon solvent in the presence of a diamine. The ratio of the number of moles of the dialkenylbenzene to the number of moles of the secondary butyllithium is substantially equal to 0.5, and the resulting initiator is a double adduct obtained by adding a secondary butyllithium molecule to each of the two double bonds of the dialkenylbenzene.

[0007] The difunctional organolithium initiator having an anionic end disclosed in the above prior art document has a molar ratio of divinylarene to organic alkali metal in the range of 0.05 to 1.0, and the conjugated diene polymer obtained by polymerization is used in the production of rubber. The rubber has many drawbacks such as low rolling resistance that causes low grip, low tensile strength and tear strength that cause low deformation resistance, low rigidity, and low abrasion resistance. The mechanical properties required for the automotive industry and other rubber products are clearly insufficient, and this is an issue that the industry eagerly desires to improve.

Summary of the Invention

[0008] In view of the above, the present invention provides a method for producing a conjugated diene polymer. In this method, the initiator is obtained by the reaction of a divinylarene-like compound and an organic alkali metal. The inventors of the present invention have surprisingly found that the rubber produced by the method of the present invention in which the molar ratio of the divinylarene-like compound to the effective active organic alkali metal is 1.3 to 5.0 has significantly better rolling resistance, the product of the breaking tensile strength and the breaking elongation strength, tear strength, and rigidity than the rubber produced by a method that does not use a divinylarene-like compound or a method in which the amount of the divinylarene-like compound is insufficient.

[0009] In one aspect, the present invention is a method for producing a conjugated diene polymer, comprising: Step (a): Formula (1):

Chemical formula

[0010] In another aspect, the present invention provides a conjugated diene polymer obtained by the above production method.

[0011] In yet another aspect, the present invention provides a rubber containing the above conjugated diene polymer.

[0012] In yet another aspect, the present invention provides a tire containing the above rubber.

Embodiments for Carrying Out the Invention

[0013] To fully understand the present invention and its claims, preferred embodiments of the present invention are illustrated below. To avoid obscuring the content of the present invention, known components, related materials, and related processing techniques may be omitted in the following description. The following description is merely a preferred embodiment of the present invention and is not intended to limit the scope of the claims of the present invention. All other equivalent changes or modifications that do not depart from the spirit disclosed in the present invention should be included within the scope of this patent application.

[0014] Method for Producing Conjugated Diene Polymer The present invention provides a method for producing a conjugated diene polymer by using anionic polymerization to obtain a conjugated diene polymer. So-called anionic polymerization means forming a living carbanion using an initiator, adding a monomer, then subjecting the monomer and the living carbanion to addition polymerization to form a polymer having a negative charge at the end of the molecular chain, and then adding a terminator to stop the reaction. The polymer is preferably obtained by a batch adiabatic process. The above production method includes the following. Step (a): Formula (1): [Chemical formula] [Wherein: A and B are C n H 2n+1 or an aromatic ring, n is 0 to 5, A and B may be the same or different, Q is an aromatic ring.] Reacting a divinylarene-like compound represented by the formula with an organic alkali metal to obtain an initiator, where the molar ratio of the divinylarene-like compound to the effective active organic alkali metal is 1.3 to 5.0, Step (b): Polymerizing a conjugated diene monomer or a conjugated diene monomer and a vinyl aromatic monomer using the initiator to obtain a conjugated diene polymer. The conjugated diene polymer may be a block copolymer or a random copolymer.

[0015] The substituents A, B, and / or Q of the divinylarene-like compound can be a substituted or unsubstituted aromatic ring containing a monocyclic, polycyclic, or fused ring, which is independently selected from the group consisting of, for example, substituted or unsubstituted benzene, naphthalene, naphthalene, anthracene, phenanthrene, fluorene, naphthacene, pyrene, biphenyl, terphenyl, quarterphenyl, phenylnel, terphenyl, perylene, indene, and any combination thereof, or a fused ring of the combination. The substituent is preferably benzene. The divinylarene-like compound can be independently selected from the group consisting of, for example, m-divinylbenzene, p-divinylbenzene, 1,2-diisopropenylbenzene, 1,3-diisopropenylbenzene, 1,4-diisopropenylbenzene, 1,3-divinylnaphthalene, 1,8-divinylnaphthalene, 1,4-divinylnaphthalene, 1,5-divinylnaphthalene, 2,3-divinylnaphthalene, 2,7-divinylnaphthalene, 2,6-vinylnaphthalene, 4,4'-divinylbiphenyl, 4,3'-divinylbiphenyl, 4,2'-divinylbiphenyl, 3,2'-divinylbiphenyl, 3,3'-divinylbiphenyl, 2,2'-divinylbiphenyl, 2,4-divinylbiphenyl, 1,2-divinyl-3,4-dimethylbenzene, 1,3-divinyl-4,5,8-tributylnaphthalene, 2,2'-divinyl-4-ethyl-4'-propylbiphenyl, and any combination thereof. The divinylarene-like compound is preferably 1,3-diisopropenylbenzene or p-divinylbenzene.

[0016] The number of moles of the active organic alkali metal means the number of moles of the organic alkali metal participating in the reaction, rather than the number of moles of the organic alkali metal added to the reactor. The number of moles can be obtained by gel permeation chromatography (GPC).

[0017] Examples of the organic alkali metal include mono-organic lithium compounds such as methyllithium, ethyllithium, n-propyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, isobutyllithium, n-pentyllithium, n-hexyllithium, benzyllithium, phenyllithium, tolyllithium and their isomers, naphthyllithium, stilbenyllithium; 1,4-dilithiobutane, 1,5-dilithiopentane, 1,2-dilithiodiphenylethane, 1,4-dilithio-1,1,4,4-tetraphenylbutane, 1,3- or 1,4-bis(1-lithio-3-methylpentyl)benzene, naphthalenedilithium, dilithiumhexylbenzene, 1,4-dilithio-2-ethylcyclohexane, 1,3,5-trilithiobenzene, 1,3,5-tris(lithiomethyl)benzene; organic sodium compounds such as naphthylsodium; organic potassium compounds such as naphthylpotassium, potassium ethoxide; and compounds having a nitrogen-lithium bond (metal amide compounds) such as lithium dimethylamide, lithium dihexylamide, lithium diisopropylamide, and lithium hexamethyleneimide. The metal amide compound is preferably a reaction product of a lithium compound such as an alkyllithium or an aromatic lithium and a secondary amine compound. Examples of the secondary amine compound include dimethylamine, diethylamine, dipropylamine, dibutylamine, dihexylamine, dibenzylamine, dodecamethyleneimine, N,N'-dimethyl-N'-trimethylsilyl-1,6-diaminohexane, piperidine, pyrrolidine, hexamethyleneimine, heptamethyleneimine, dicyclohexylamine, N-methylbenzylamine, di-(2-ethylhexyl)amine, diallylamine, morpholine, N-(trimethylsilyl)piperazine, N-(tert-butyldimethylsilyl)piperazine, 1,3-bistrimethylsilyl-1,3,5-triazinan.Examples of the organic alkaline earth metal compounds include di-n-butylmagnesium, di-n-hexylmagnesium, diethoxycalcium, calcium stearate, calcium distearate, di-tert-butoxystrontium, diethoxy barium, barium diisopropoxide, diethylmercaptopotassium, barium di-tert-butoxide, barium diphenoxide, barium distearate, and diketylbarium. These polymerization initiators may be used alone or in combination of two or more. The initiator is preferably a lithium compound. The lithium compound is preferably n-butyllithium and sec-butyllithium.

[0018] The conjugated diene monomer can be a conjugated diene having 4 to 12 carbon atoms. Specific examples of the conjugated diene monomer include: 1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 1,3-heptadiene, 2-methyl-1,3-butadiene (isoprene), 2-methyl-1,3-pentadiene, 2-hexyl-1,3-butadiene, 2-phenyl-1,3-butadiene, 2-phenyl-1,3-pentadiene, 2-p-tolyl-1,3-butadiene, 2-benzyl-1,3-butadiene, 3-methyl-1,3-pentadiene, 3-methyl-1,3-hexadiene, 3-butyl-1,3-octadiene, 3-phenyl-1,3-pentadiene, 4-methyl-1,3-pentadiene, 1,4-diphenyl-1,3-butadiene, 2,3-dimethyl-1,3-butadiene, 2,3-dimethyl-1,3-pentadiene, 2,3-dibenzyl-1,3-butadiene, 4,5-diethyl-1,3-octadiene, myrcene, and any combination thereof. The conjugated diene monomer is preferably 1,3-butadiene and isoprene.

[0019] Specific examples of vinyl aromatic monomers suitable for use in the present invention include: styrene, methylstyrene and all its isomers, ethylstyrene and all its isomers, tert-butylstyrene and all its isomers, dimethylstyrene and all its isomers, methoxystyrene and all its isomers, cyclohexylstyrene and all its isomers, vinylbiphenyl, 1-vinyl-5-hexylnaphthalene, vinylnaphthalene, vinylanthracene, 2,4-diisopropylstyrene, 5-tert-butyl-2-methylstyrene, divinylbenzene, trivinylbenzene, divinylnaphthalene, tert-butoxystyrene, 4-propylstyrene, 4-dodecylstyrene, 2-ethyl-4-benzylstyrene, 4-(phenylbutyl)styrene, N-4-vinylphenyl-N,N-dimethylamine, (4-vinylphenyl)dimethylaminoethyl ether, N,N-dimethylaminomethylstyrene, N,N-dimethylaminoethylstyrene, N,N-diethylaminomethylstyrene, N,N-diethylaminoethylstyrene, vinylxylene, vinylpyridine, diphenylethylene, 2,4,6-trimethylstyrene, α-methyl-2,6-dimethylstyrene, α-methyl-2,4-dimethylstyrene, β-methyl-2,6-dimethylstyrene, β-methyl-2,4-dimethylstyrene, indene, diphenylethylene containing a tertiary amino group such as 1-(4-N,N-dimethylaminophenyl)-1-phenylethene, and any combination thereof. The vinyl aromatic monomers suitable for use in the present invention are preferably styrene or methylstyrene and all their isomers.

[0020] Regarding step (a), in one embodiment, a divinylarene-like compound and an organic alkali metal are mixed and reacted in a solvent. The solvent suitable for the polymerization reaction is an inert organic solvent. An inert organic solvent refers to a solvent that does not participate in the polymerization. Examples of such solvents include aliphatic hydrocarbons such as n-butane, isobutane, n-pentane, isopentane, 2,2,4-trimethylpentane, isohexane, n-hexane, isoheptane, n-heptane, isooctane, n-octane, and n-decane; cycloalkane compounds such as cyclohexane, methylcyclohexane, ethylcyclohexane, cyclopentane, cycloheptane, methylcyclopentane, and methylcycloheptane; or aromatic hydrocarbon compounds such as benzene, toluene, xylene, ethylbenzene, diethylbenzene, and propylbenzene. These inert organic solvents can be used alone or in combination of two or more. The inert organic solvent is preferably cyclohexane. In another embodiment, after reacting a part of the divinylarene-like compound with the organic alkali metal for a certain period of time, the remaining part of the divinylarene-like compound is added and the reaction is continued for another period of time. In another embodiment, the concentration of the divinylarene-like compound in the solvent is 0.001 to 20% by weight. In another embodiment, the reaction temperature is 0 to 60°C, preferably a high temperature of 55°C to 60°C. The temperature can be controlled by adiabatic reaction, isothermal control, or partial cooling.

[0021] Generally, when only an inert organic solvent is used as the solvent, the polymerization rate of the vinyl aromatic monomer is significantly different from that of the conjugated diene monomer. This difference can be resolved by adding a polar solvent in step (b). In one embodiment, a cyclic ether and / or a diether compound can be added, and the cyclic ether can be a monocyclic ether or a bicyclic ether. For example, the monocyclic ether can be independently selected from the group consisting of tetrahydrofuran, furan, tetrahydropyran, 2-methyl-tetrahydropyran, 3-methyl-tetrahydropyran, crown ethers (such as 12-crown-4 ether), 15-crown-5 ether, or 18-crown-6 ether, 1,4-dioxane, and any combination thereof. The bicyclic ether can be 2,2-bis(2-tetrahydrofuryl)propane. The diether is independently selected from the group consisting of diethyl ether, di-n-propyl ether, di-n-butyl ether, ethylene glycol dibutyl ether, ethylene glycol diethyl ether, ethylene glycol dimethyl ether, diethylene glycol dibutyl ether, diethylene glycol diethyl ether, diethylene glycol dimethyl ether, methyl n-propyl ether, diisopropyl ether, tertiary amyl ethyl ether, methyl tertiary butyl ether or ethyl tertiary butyl ether, and any combination thereof. The polar solvent is preferably tetrahydrofuran, diethyl ether, ethylene glycol dimethyl ether, and ethylene glycol diethyl ether. In another embodiment, before adding the organic alkali metal in step (a), a cyclic ether and / or a diether compound can be added and mixed with the divinylarene-like compound.

[0022] In one embodiment, the method for producing a conjugated diene polymer of the present invention further includes step (c): adding a silicon-containing modifier after step (b). The purpose of adding the silicon-containing modifier is to increase the interaction between the conjugated diene polymer and various additives through covalent bonds, hydrogen bonds, and other binding forces or van der Waals forces. The silicon-containing modifier has a monosilane structure and binds to the conjugated diene polymer through one or more of the four covalent bond positions of the silicon-containing modifier that react with the organic alkali metal itself. The molar ratio of the silicon-containing modifier to the effective active organic alkali metal is 1.3 to 5.0, preferably 1.4 to 3.5, more preferably 1.5 to 2.5.

[0023] The structure of the silicon-containing modifier is represented by formula (2): [Chemical formula] [Wherein: A1, A2, and A3 are alkane, alkoxy, or halogen, The carbon number of the alkane or alkoxy is C1 - C5, At least two of A1, A2, and A3 are alkoxy or halogen, X is a group containing at least one of a nitrogen atom, an oxygen atom, a sulfur atom, and a phosphorus atom, n is 1 - 10.] The silicon-containing modifier is preferably 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine or 3-(trimethoxysilyl)-N,N-dimethylpropane-1-amine.

[0024] Conjugated diene polymer

[0025] The present invention also provides a conjugated diene polymer obtained by using the method for producing a conjugated diene polymer of the present invention. According to various embodiments of the present invention, the Mooney viscosity of the conjugated diene polymer is in the range of 20 to 100, preferably 30 to 75, more preferably 30 to 65. The glass transition temperature range of the conjugated diene polymer is -15 to -70 °C, preferably -20 to -65 °C.

[0026] According to various embodiments of the present invention, the conjugated diene polymer is measured by gel permeation chromatography (GPC), has m peaks (m is 1 or more), and a first peak (Mi) with the lowest weight average molecular weight, and 5×10 4 ~150×10 4 g / mol, preferably 10×10 4 ~150×10 4 g / mol, more preferably 15×10 4 ~150×10 4 g / mol.

[0027] According to various embodiments of the present invention, the weight average molecular weight of the conjugated diene polymer is 15×10 4 ~200×10 4 g / mol, preferably 20×10 4 to 180×10 4 g / mol, more preferably 25×10 4 ~180×10 4 g / mol.

[0028] Applications of conjugated diene polymers

[0029] The present invention also provides a rubber obtained by mixing the conjugated diene polymer of the present invention with other components. Specific examples of the other components include emulsion polystyrene-butadiene copolymer, polybutadiene rubber, butadiene-isoprene copolymer, and butyl rubber. In one embodiment, the other components further include natural rubber, ethylene-propylene copolymer, and ethylene-octene copolymer. The above compositions may be used by mixing two or more of them. When the total amount of all components is 100 parts by weight, the content of the conjugated diene polymer in the rubber composition is preferably at least 10 parts by weight, more preferably at least 20 parts by weight.

[0030] Furthermore, the rubber of the present invention may contain additives. Specific examples of the additives include vulcanizing agents such as sulfur; vulcanization accelerators such as thiazole-based vulcanization accelerators, thiuram-based vulcanization accelerators, or sulfenamide-based vulcanization accelerators; vulcanization activators such as stearic acid or zinc oxide; organic peroxides; reinforcing agents such as white smoke or carbon black; fillers such as calcium carbonate or talc; silane coupling agents; extender oils; processing aids; antioxidants; and lubricants. In one embodiment, the additives further include at least one or a combination of silicon dioxide, extender oil, antioxidant, stearic acid, wax, vulcanization accelerator, processing accelerator, and carbon black.

[0031] The rubber of the present invention can be obtained by mixing the conjugated diene polymer of the present invention with other components and / or additives, and all components can be kneaded using a known mixer such as a roller, a Banbury mixer, or an internal mixer. Regarding the kneading conditions, when mixing additives other than a vulcanizing agent or a vulcanization accelerator, the kneading temperature is usually 50°C to 200°C, preferably 80°C to 150°C, and the kneading time is usually 30 seconds to 30 minutes, preferably 1 minute to 30 minutes. When mixing a vulcanizing agent or a vulcanization accelerator, the kneading temperature is usually 100°C or lower, preferably 25°C to 90°C. The vulcanizing agent or the vulcanization accelerator can be incorporated into the composition by vulcanization such as press vulcanization, and the vulcanization temperature is usually 120°C to 200°C, preferably 140°C to 180°C.

[0032] The rubber of the present invention can be used for tires, shoe soles, floor materials, and vibration damping materials, and is particularly suitable for use in tires to improve the low rolling resistance of tire treads, enhance the wet skid resistance, and improve the handling stability and reliability.

[0033] The production method of the conjugated diene polymer of the present invention and the obtained conjugated diene polymer, particularly the production method of the styrene-butadiene copolymer and the obtained styrene-butadiene copolymer, will be described in detail by the following examples.

[0034] Example 1

[0035] Example 1-1

[0036] Pre-start reaction: 1 g of 1,3-diisopropenylbenzene was added to 20 g of a cyclohexane solution of 1 g of tetrahydrofuran and 0.25 g of ethylene glycol diethyl ether at room temperature (27°C), and then 15 g of n-butyllithium (5 wt% cyclohexane solution) was added to the mixture and reacted for 30 minutes to obtain an initiator. The initiator was stored in a cooling environment at 4°C.

[0037] Coincidence: The initiator obtained from the pre-start reaction and 0.2 g of 1,3-diisopropenylbenzene were mixed in 5525 g of cyclohexane, 10 g of tetrahydrofuran and 2.5 g of ethylene glycol diethyl ether were added, and the mixture was reacted for 15 minutes. Subsequently, 665 g of 1,3-butadiene and 200 g of styrene were added and polymerized. 15 minutes after the polymerization temperature reached 60 °C, 35 g of 1,3-butadiene was added and reacted for 5 minutes. Then, 1.4 g of 4-{3-[dimethoxy(methyl)silyl]propyl}morphine was added and reacted for 30 minutes, and finally 0.5 g of methanol was added to stop the reaction.

[0038] Examples 1-2 and 1-3 had the same reaction steps as Example 1-1, differing only in the addition amounts of 1,3-diisopropenylbenzene and 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine. More specifically, in Example 1-2, the addition amounts of 1,3-diisopropenylbenzene in the pre-start step and the polymerization step were 1 g and 0.7 g, respectively. The addition amount of 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine was 1.5 g. In Example 1-3, the addition amounts of 1,3-diisopropenylbenzene in the pre-start step and the polymerization step were 1 g and 0.4 g, respectively. The addition amount of 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine was 1.1 g.

[0039] The advantage of Example 1 is that the initiator can be prepared in advance, stored in a cooling environment, and used for subsequent polymerization. Therefore, during polymerization, the reaction time of 1,3-diisopropenylbenzene mixed in the cyclohexane solution is shortened, and the yield increases.

[0040] Example 2

[0041] The difference between Example 2 and Example 1 is that in Example 2, polymerization was carried out immediately after the preparation of the initiator, while in Example 1, the initiator was stored in a cooling environment for later use.

[0042] Example 2-1

[0043] At room temperature (27 °C), 0.8 g of 1,3 - diisopropenylbenzene was mixed with 5525 g of a cyclohexane solution containing 10 g of tetrahydrofuran and 2.5 g of ethylene glycol diethyl ether. Then, 20 g of n - butyllithium (5 wt% cyclohexane solution) was added to the mixture and reacted for 60 minutes. Thereafter, 665 g of 1,3 - butadiene and 200 g of styrene were added and polymerized. 15 minutes after the polymerization temperature reached 60 °C, 35 g of 1,3 - butadiene was added and reacted for 5 minutes. Then, 1.6 g of 4 - {3 - [dimethoxy(methyl)silyl]propyl} morpholine was added and reacted for 30 minutes, and finally 0.5 g of methanol was added to stop the reaction.

[0044] Examples 2 - 2 to 2 - 7 had the same reaction steps as Example 2 - 1, differing only in the addition amounts of 1,3 - diisopropenylbenzene and 4 - {3 - [dimethoxy(methyl)silyl]propyl} morpholine. More specifically, in Example 2 - 2, the addition amounts of 1,3 - diisopropenylbenzene and 4 - {3 - [dimethoxy(methyl)silyl]propyl} morpholine were 1.2 g and 1.5 g, respectively. In Example 2 - 3, the addition amounts were 1.35 g and 1.7 g, respectively. In Example 2 - 4, the addition amounts were 1.8 g and 1.6 g, respectively. In Example 2 - 5, the addition amounts were 1.9 g and 1.5 g, respectively. In Example 2 - 6, the addition amounts were 1.8 g and 3.5 g, respectively. In Example 2 - 7, the addition amounts were 1 g and 2.4 g, respectively.

[0045] Example 3

[0046] Example 3-1

[0047] At room temperature (27 °C), 1 g of 1,3 - diisopropenylbenzene was mixed with 5525 g of a cyclohexane solution containing 10 g of tetrahydrofuran and 0.2 g of ethylene glycol diethyl ether. After heating to 55 °C, 20 g of n - butyllithium (5 wt% cyclohexane solution) was added to the mixture and reacted for 30 minutes. Subsequently, 780 g of 1,3 - butadiene and 90 g of styrene were added and polymerized. 15 minutes after the polymerization temperature reached 60 °C, 30 g of 1,3 - butadiene was added and reacted for 5 minutes. Then, 1.1 g of 4 - {3 - [dimethoxy(methyl)silyl]propyl}morphine was added and reacted for 30 minutes, and finally 0.5 g of methanol was added to terminate the reaction.

[0048] Examples 3 - 2 and 3 - 3 had the same reaction steps as Example 3 - 1, differing only in the addition amounts of 1,3 - diisopropenylbenzene and 4 - {3 - [dimethoxy(methyl)silyl]propyl}morphine. More specifically, in Example 3 - 2, the addition amounts of 1,3 - diisopropenylbenzene and 4 - {3 - [dimethoxy(methyl)silyl]propyl}morphine were 1 g and 1.7 g, respectively. In Example 3 - 3, the addition amounts of 1,3 - diisopropenylbenzene and 4 - {3 - [dimethoxy(methyl)silyl]propyl}morphine were 1.2 g and 1.3 g, respectively.

[0049] The advantage of Example 3 is that by raising the temperature to 55 °C, the reaction time of n - butyllithium during the preparation of the initiator was shortened, and by reducing the amount of ethylene glycol diethyl ether used, a conjugated diene - based polymer with a lower glass transition temperature was obtained.

[0050] Comparative Example 1

[0051] The differences between Comparative Example 1 and Example 2 are as follows: Regarding the preparation of the initiator, in Comparative Example 1, a smaller amount of 1,3 - diisopropenylbenzene was added than in Example 2; regarding the polymerization, in Comparative Example 1, 4 - {3 - [dimethoxy(methyl)silyl]propyl}morpholine was not added, while in Example 2, 4 - {3 - [dimethoxy(methyl)silyl]propyl}morpholine was used. More specifically, at room temperature (27 °C), 0.4 g of 1,3 - diisopropenylbenzene was mixed into 5525 g of a cyclohexane solution containing 10 g of tetrahydrofuran and 2.5 g of ethylene glycol diethyl ether, and then 20 g of n - butyllithium (5 wt% cyclohexane solution) was added to the mixture and reacted for 60 minutes. Subsequently, 665 g of 1,3 - butadiene and 200 g of styrene were added and polymerized. 15 minutes after the polymerization temperature reached 60 °C, 35 g of 1,3 - butadiene was added and reacted for 5 minutes, and finally 0.5 g of methanol was added to stop the reaction.

[0052] Comparative Example 2

[0053] The differences between Comparative Example 2 and Example 2 are as follows: Regarding the preparation of the initiator, in Comparative Example 2, 1,3 - diisopropenylbenzene was not added, while in Example 2, 1,3 - diisopropenylbenzene was used. More specifically, at room temperature (27 °C), 665 g of 1,3 - butadiene and 200 g of styrene were mixed into 5525 g of a cyclohexane solution containing 10 g of tetrahydrofuran and 2.5 g of ethylene glycol diethyl ether, and then 20 g of n - butyllithium (5 wt% cyclohexane solution) was added to the mixture and polymerized. 15 minutes after the polymerization temperature reached 60 °C, 35 g of 1,3 - butadiene was added and reacted for 5 minutes. Subsequently, 1.6 g of 4 - {3 - [dimethoxy(methyl)silyl]propyl}morphine was added and reacted for 30 minutes, and finally 0.5 g of methanol was added to stop the reaction.

[0054] Comparative Example 3

[0055] The difference between Comparative Example 3 and Example 2 is that, regarding the polymerization, in Comparative Example 3, a smaller amount of 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine was added than in Example 2. More specifically, at room temperature (27 °C), 1.5 g of 1,3-diisopropenylbenzene was mixed into 5525 g of a cyclohexane solution of 10 g of tetrahydrofuran and 2.5 g of ethylene glycol diethyl ether, and then 20 g of n-butyllithium (5 wt% cyclohexane solution) was added to the mixture and reacted for 60 minutes. Next, 665 g of 1,3-butadiene and 200 g of styrene were added and polymerized. 15 minutes after the polymerization temperature reached 60 °C, 35 g of 1,3-butadiene was added and reacted for 5 minutes. Then, 0.4 g of 4-{3-[dimethoxy(methyl)silyl]propyl}morphine was added and reacted for 30 minutes, and finally 0.5 g of methanol was added to stop the reaction.

[0056] Comparative Example 4

[0057] The difference between Comparative Example 4 and Example 2 is that, regarding the preparation of the initiator, in Comparative Example 4, a smaller amount of 1,3-diisopropenylbenzene was added than in Example 2. More specifically, at room temperature (27 °C), 0.4 g of 1,3-diisopropenylbenzene was mixed into 5525 g of a cyclohexane solution of 10 g of tetrahydrofuran and 2.5 g of ethylene glycol diethyl ether, and then 20 g of n-butyllithium (5 wt% cyclohexane solution) was added and reacted for 60 minutes. Then, 665 g of 1,3-butadiene and 200 g of styrene were added and polymerized. 15 minutes after the polymerization temperature reached 60 °C, 35 g of 1,3-butadiene was added and reacted for 5 minutes. Then, 1.6 g of 4-{3-[dimethoxy(methyl)silyl]propyl}morphine was added and reacted for 30 minutes, and finally 0.5 g of methanol was added to stop the reaction.

[0058] Comparative Example 5

[0059] The difference between Comparative Example 5 and Example 3 is that, regarding the preparation of the initiator, in Comparative Example 5, a smaller amount of 1,3 - diisopropenylbenzene was added than in Example 3. More specifically, at room temperature (27 °C), 0.4 g of 1,3 - diisopropenylbenzene was mixed into 5525 g of a cyclohexane solution containing 10 g of tetrahydrofuran and 0.2 g of ethylene glycol diethyl ether. After heating to 55 °C, 20 g of n - butyllithium (5 wt% cyclohexane solution) was added and reacted for 30 minutes. Then, 780 g of 1,3 - butadiene and 90 g of styrene were added and polymerized. 15 minutes after the polymerization temperature reached 60 °C, 30 g of 1,3 - butadiene was added and reacted for 5 minutes. Then, 1.6 g of 4 - {3 - [dimethoxy(methyl)silyl]propyl} morphine was added and reacted for 30 minutes, and finally 0.5 g of methanol was added to stop the reaction.

[0060] For testing mechanical properties, a method for producing rubber test pieces from the conjugated diene - based polymers obtained from the above - mentioned Examples and Comparative Examples of the present invention will be described below.

[0061] 70 parts by weight of the conjugated diene - based polymer obtained in each Example and Comparative Example, 30 parts by weight of polybutadiene rubber (trade name: TAIPOL BR0150, TSRC), 70 parts by weight of silicon dioxide, 37.5 parts by weight of extender oil (TDAE, IRPC), 11.2 parts by weight of silane (trade name: Si69, EVONIK), 2 parts by weight of stearic acid, 3 parts by weight of zinc oxide, 1 part by weight of antioxidant (trade name: Antigen), 1.5 parts by weight of sulfur, and 3.3 parts by weight of vulcanization accelerator (including 1.8 parts by weight of N - cyclohexyl - 2 - benzothiazole sulfenamide (CBS) and 1.5 parts by weight of 1,3 - diphenylguanidine (DPG)) were kneaded to form rubber. This rubber was formed into a sheet film using a two - roll machine, and the sheet film was vulcanized (heated at 160 °C for 45 minutes) to obtain a vulcanized sheet film.

[0062] Tables 1 - 3 show the compositions and physical properties of the conjugated diene - based polymers of each Example and Comparative Example, and the mechanical properties of the rubber test pieces prepared therefrom.

[0063] Analysis Method of Conjugated Diene Polymer

[0064] Molar ratio of divinylarene-like compound to effective active organic alkali metal: The molar ratio is the ratio (Q / M) of the number of moles (Q) of the divinylarene-like compound to the number of moles (M) of the organic alkali metal involved in the reaction. Q is the weight of the divinylarene-like compound / the molecular weight of the divinylarene-like compound, and M is the total weight of the monomers added to the reaction / the lowest weight average molecular weight (Mi) represented by the first peak. The first peak (Mi) is obtained by analyzing the conjugated diene polymer or modified conjugated diene polymer by gel permeation chromatography (GPC).

[0065] Molar ratio of silicon-containing modifier to effective active organic alkali metal: The molar ratio is the ratio (Si / M) of the number of moles (Si) of the silicon-containing modifier to the number of moles (M) of the organic alkali metal involved in the reaction. Si is the weight of the silicon-containing modifier / the molecular weight of the silicon-containing modifier, and M is the total weight of the monomers added to the reaction / the lowest weight average molecular weight (Mi) represented by the first peak. The first peak (Mi) is obtained by analyzing the modified conjugated diene polymer by gel permeation chromatography (GPC).

[0066] Coupling ratio (CR%): The modified conjugated diene polymer has the characteristics of m peaks measured by gel permeation chromatography (GPC). Here, the coupling ratio = [(total integrated area of m peaks - integrated area of the first peak) / total integrated area of m peaks] × 100%. Tetrahydrofuran was used as the mobile phase for the analysis.

[0067] Weight average molecular weight (Mw) and molecular weight distribution (MWD): Mw and MWD were measured by gel permeation chromatography (GPC) (Waters 1525 Binary HPLC Pump and Waters 2414 Refractive Index Detector), and tetrahydrofuran was used as the eluent at a flow rate of 1 ml / min.

[0068] Mooney viscosity (ML 1+4 at 100 °C): ALPHA Mooney MV 2000 and standard test method ASTM D-1646 were used.

[0069] Glass transition temperature (Tg, °C): The glass transition temperature was determined using a differential scanning calorimeter (DSC) (TA Instrument Q200) at a scanning rate of 20 °C / min, a scanning range of -90 °C to 100 °C, and nitrogen as the purge gas.

[0070] Analysis method of rubber test specimens

[0071] Loss tangent (tanδ): This index is used for measuring the rolling resistance (RR) of tread rubber stock made from conjugated diene polymers. A strain sweep was performed using an ARES-G2 model (TA Instruments) (sample temperature 60 °C, strain scanning range 0.1% to 10%, and strain value 5.0%) to measure the changes in the storage modulus (G’) and loss modulus (G”) of the test specimens. The index was calculated by the formula “tanδ = G” / G’.

[0072] Tensile strength at break (Tb, Mpa): Tb was measured using an INSTRON 33R4464 model based on ASTM D 412 standard.

[0073] Elongation at break (Eb, %): Eb was measured using an INSTRON 33R4464 model based on ASTM D 412 standard.

[0074] Tear strength (N / mm): Tear strength was measured using an INSTRON 33R4464 model based on ASTM D 412 standard.

[0075] Rigidity (Mpa): The storage modulus (G’) of the test specimens was measured using a strain sweep with an ARES-G2 model (TA Instruments) (sample temperature 60 °C, strain scan range 0.1% to 10%, and strain value 5.0%).

[0076] Wear test (DIN): Using the GT-7012-DN model, the index was measured based on the ASTM D5963 standard.

[0077] Note that the values of the mechanical properties of each of the following rubber test pieces are not actual values. The values are reference values (reference value 100) showing a comparison between any of the examples and comparative examples of the present invention.

[0078]

Table 1

[0079] Table 1 shows various properties of the conjugated diene polymers of Examples 1-1 to 1-3 and the rubber test pieces produced therefrom. In Examples 1-1 to 1-3, both 1,3-diisopropenylbenzene and 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine were added, and both the Q / M value and the Si / M value were within the scope of the present invention (i.e., 1.3 to 5.0). In Comparative Example 1, 1,3-diisopropenylbenzene was added and 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine was not added, and neither the Q / M value nor the Si / M value of Comparative Example 1 was within the scope of the present invention. In Comparative Example 2, 1,3-diisopropenylbenzene was not added and 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine was added. The Si / M value of Comparative Example 2 was within the scope of the present invention, but the Q / M value was not within the scope. In Comparative Example 3, both 1,3-diisopropenylbenzene and 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine were added. The Q / M value of Comparative Example 3 was within the scope of the present invention, but the Si / M value was not within the scope. In Comparative Example 4, both 1,3-diisopropenylbenzene and 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine were added. The Si / M value of Comparative Example 4 was within the scope of the present invention, but the Q / M value was not within the scope of the present invention. Compared with Comparative Examples 1 to 4, Examples 1-1 to 1-3 all show that the rubber produced from the polymer of the present invention has excellent mechanical properties such as rolling resistance, the product of the tensile strength at break and the elongation at break, tear strength, and rigidity, without being affected by the glass transition temperature of the polymer.

[0080] Based on Comparative Example 2, Comparative Example 4, and Examples 1-2, when only 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine was added such that the Si / M value was within the scope of the present invention (Comparative Example 2), the rubber produced therefrom had poor rolling resistance and rigidity. When 1,3-diisopropenylbenzene was further added (Comparative Example 4), the rolling resistance and rigidity of the rubber produced therefrom were gradually improved. When 1,3-diisopropenylbenzene was further added such that the Q / M value was within the scope of the present invention (Examples 1-2), the resulting rubber had significantly excellent mechanical properties such as rolling resistance, the product of the tensile strength at break and the elongation at break, tear strength, and rigidity.

[0081] Based on Comparative Example 1, Comparative Example 3, and Examples 1-3, when only 1,3-diisopropenylbenzene was added (Comparative Example 1), the rubbers produced therefrom had poor rolling resistance and rigidity. When 1,3-diisopropenylbenzene was further added to such an extent that the Q / M value was within the scope of the present invention (Comparative Example 3), the rolling resistance and rigidity of the rubber produced therefrom were improved. When 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine was further added such that the Si / M value was within the scope of the present invention (Examples 1-3), the resulting rubber had significantly excellent mechanical properties such as rolling resistance, the product of the tensile strength at break and the elongation at break, tear strength, and rigidity.

[0082]

Table 2-1

[0083]

Table 2-2

[0084] Table 2 shows various properties of the conjugated diene polymers of Examples 2-1 to 2-7 and the rubber test pieces produced therefrom. In Examples 2-1 to 2-7, both 1,3-diisopropenylbenzene and 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine were added, and both the Q / M value and the Si / M value were within the scope of the present invention (i.e., 1.3 to 5.0). In Comparative Example 1, 1,3-diisopropenylbenzene was added, and 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine was not added, and neither the Q / M value nor the Si / M value of Comparative Example 1 was within the scope of the present invention. In Comparative Example 2, 1,3-diisopropenylbenzene was not added, and 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine was added. The Si / M value of Comparative Example 2 was within the scope of the present invention, but the Q / M value was not within the scope. In Comparative Example 3, both 1,3-diisopropenylbenzene and 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine were added. The Q / M value of Comparative Example 3 was within the scope of the present invention, but the Si / M value was not within the scope. In Comparative Example 4, both 1,3-diisopropenylbenzene and 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine were added. The Si / M value of Comparative Example 4 was within the scope of the present invention, but the Q / M value was not within the scope of the present invention. Compared with Comparative Examples 1 to 4, Examples 2-1 to 2-7 all show that the rubber produced from the polymer of the present invention has excellent mechanical properties such as rolling resistance, the product of the tensile strength at break and the elongation at break, tear strength, and rigidity without being affected by the glass transition temperature of the polymer.

[0085] Based on Comparative Example 2, Comparative Example 4, and Examples 2-1 to 2-5, when only 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine was added such that the Si / M value was within the scope of the present invention (Comparative Example 2), the rubber produced therefrom had poor rolling resistance and rigidity. When 1,3-diisopropenylbenzene was further added (Comparative Example 4), the rolling resistance and rigidity of the rubber produced therefrom were gradually improved. When 1,3-diisopropenylbenzene was further added such that the Q / M value was within the scope of the present invention (Examples 2-1 to 2-5), the resulting rubber had significantly excellent mechanical properties such as rolling resistance, the product of the tensile strength at break and the elongation at break, tear strength, and rigidity.

[0086] In Example 1-1, the initiator was stored in a cooling environment and used for subsequent polymerization. On the other hand, in Example 2-2, the initiator was newly prepared immediately before polymerization. The compositions and physical properties of the conjugated diene polymers obtained in Example 1-1 and Example 2-2 were substantially the same, and the rubbers produced therefrom had significantly better mechanical properties than the rubbers produced from the polymers obtained in Comparative Examples 1 to 4. Compared with Example 2-2, the polymerization reaction time of Example 1-1 was shorter and the yield was higher.

[0087]

Table 3

[0088] Table 3 shows various properties of the conjugated diene polymers of Examples 3-1 to 3-3 and the rubber test pieces made therefrom. In Examples 3-1 to 3-3, both 1,3-diisopropenylbenzene and 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine were added, and both the Q / M value and the Si / M value were within the scope of the present invention (i.e., 1.3 to 5.0). In Comparative Example 5, both 1,3-diisopropenylbenzene and 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine were added. The Si / M value of Comparative Example 5 was within the scope of the present invention, but the Q / M value was not within the scope. Compared with Comparative Example 5, in all of Examples 3-1 to 3-3, even when 1,3-diisopropenylbenzene was added until the Q / M value reached the bottom of the range (i.e., 1.3), without affecting the glass transition temperature of the polymer, the rubber produced from the polymers obtained in Examples 3-1 to 3-3 exhibited excellent mechanical properties such as rolling resistance and abrasion.

[0089] The Q / M values and Si / M values of the polymers obtained in Example 2-1 and Example 3-2 were very close and both were within the scope of the present invention. In Example 2-1, more styrene was used (the weight ratio of butadiene to styrene was 78 / 22), and as a result, the glass transition temperature of the polymer was higher (-24 °C), and the rubber produced therefrom was suitable for use in summer. In contrast, in Example 3-2, more 1,3-butadiene was used (the weight ratio of butadiene to styrene was 90 / 10), and as a result, the polymer glass transition temperature was lower (-61 °C), and the rubber made therefrom was suitable for use in winter. The rubber produced from the polymer obtained in Example 2-1 had significantly better various mechanical properties than the rubbers produced from the polymers obtained in Comparative Examples 1 to 4. In addition, the rubber produced from the polymer obtained in Example 3-2 had significantly better various mechanical properties than the rubber produced from the polymer obtained in Comparative Example 5. Compared with Comparative Example 2-1, in Example 3-2, by raising the temperature, the reaction time of n-butyllithium in the preparation of the initiator was shortened and the yield was improved.

[0090] The present invention has been disclosed together with preferred embodiments, but these are not intended to limit the present invention, and those skilled in the art can make changes and modifications without departing from the spirit and scope of the present invention. Therefore, the scope of the present invention is preferentially defined by the claims of the patent application.

Claims

1. A method for producing a conjugated diene polymer, comprising the steps of: Step (a): Formula (1): 【Chemistry 1】 [In the formula: A and B are C ｎ H ２ｎ＋１ or an aromatic ring, n is 0 to 5; A and B may be the same or different; Q is an aromatic ring. with an organic alkali metal to obtain an initiator, wherein the molar ratio of the divinylarene-like compound to the available active organic alkali metal is 1.3 to 5.0; Step (b): polymerizing a conjugated diene monomer, or a conjugated diene monomer and a vinyl aromatic monomer, using an initiator to obtain a conjugated diene polymer; A method for producing a conjugated diene polymer, comprising:

2. 2. The method for producing a conjugated diene polymer according to claim 1, wherein the divinylarene-like compound is 1,3-diisopropenylbenzene or p-divinylbenzene.

3. 2. The method for producing a conjugated diene-based polymer according to claim 1, wherein step (a) further comprises reacting a portion of the divinylarene-like compound with an organoalkali metal for a first period of time and adding a remaining portion of the divinylarene-like compound and reacting for a second period of time.

4. The method for producing a conjugated diene-based polymer according to claim 1, wherein the step (a) further comprises adjusting the concentration of the divinylarene-like compound in the solvent to 0.001 to 20% by weight.

5. The method for producing a conjugated diene-based polymer according to claim 1, wherein the step (a) further comprises increasing the temperature to 55°C to 60°C and carrying out the reaction.

6. The method for producing a conjugated diene-based polymer according to claim 1, further comprising adding a cyclic ether and / or diether compound in the step (b).

7. The method for producing a conjugated diene polymer according to claim 6, wherein the cyclic ether compound is tetrahydrofuran, and the diether compound is ethylene glycol diethyl ether.

8. 2. The method for producing a conjugated diene-based polymer according to claim 1, wherein the step (a) further comprises adding a cyclic ether and / or diether compound and mixing it with the divinylarene-like compound before adding the organic alkali metal.

9. Step (c): After step (b), further comprising adding a silicon-containing modifier; The silicon-containing modifier has the formula (2): 【Chemistry 2】 [In the formula: A １ , A ２ and A ３ is an alkane, an alkoxy or a halogen; The number of carbon atoms in the alkane or alkoxy is C1 to C5; A １ , A ２ and A ３ at least two of are alkoxy or halogen; X is a group containing at least one of a nitrogen atom, an oxygen atom, a sulfur atom, and a phosphorus atom; n is 1 to 10. The method for producing the conjugated diene polymer according to claim 1 ,

10. The method for producing a conjugated diene polymer according to claim 9, wherein the silicon-containing modifier is 4-{3-[dimethoxy(methyl)silyl]propyl}morpholine or 3-(trimethoxysilyl)-N,N-dimethylpropan-1-amine.

11. 10. The method for producing a conjugated diene-based polymer according to claim 9, wherein step (c) further comprises a molar ratio of silicon-containing modifier to available active organoalkali metal of 1.3 to 5.

0.

12. 10. The method for producing a conjugated diene-based polymer according to claim 9, wherein step (c) further comprises a molar ratio of silicon-containing modifier to available active organoalkali metal of 1.4 to 3.

5.

13. 10. The method for producing a conjugated diene-based polymer according to claim 9, wherein step (c) further comprises a molar ratio of silicon-containing modifier to available active organoalkali metal of 1.5 to 2.

5.

14. A conjugated diene polymer obtained by the production method according to any one of claims 1 to 13.

15. A rubber comprising the conjugated diene polymer according to claim 14.

16. 16. The rubber of claim 15, further comprising an item independently selected from the group consisting of silicon dioxide, extending oils, antioxidants, stearic acid, waxes, vulcanization accelerators, processing accelerators, carbon black, and any combination thereof.

17. A tire comprising the rubber according to claim 15 or 16.

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