KR101086732B1 - Method for preparing conjugated diene based polymer using mixed heptanes solvent - Google Patents

Abstract

The present invention relates to a method for preparing a conjugated diene-based polymer using a heptane mixed solvent system, and more specifically, using a heptane mixed solvent system consisting of paraffinic heptane and naphthic heptane as a solution polymerization solvent. The present invention relates to a method for producing a conjugated diene polymer prepared by homopolymerizing a conjugated diene monomer in the presence of a lithium polymerization initiator or copolymerizing a conjugated diene monomer and a vinyl aromatic monomer.

The conjugated diene-based copolymer prepared by the production method of the present invention can synthesize a random copolymer having a vinyl aromatic monomer block content of up to 3% by weight, and the homopolymers and copolymers prepared are commonly excellent at room temperature. It has storage stability and excellent mechanical properties and shows excellent commercial properties for inorganic filler components such as carbon black and silica. Therefore, the conjugated diene-based polymer prepared by the production method of the present invention can be usefully used as a tire tread material used in combination with the inorganic filler component.

Anionic polymerization, conjugated diene polymer, styrene-butadiene copolymer, heptane mixed solvent system, solution polymerization

Description

Method for preparing conjugated diene polymer using heptane mixed solvent system {Method for preparing conjugated diene based polymer using mixed heptanes solvent}

The present invention relates to a method for preparing a conjugated diene-based polymer using a heptane mixed solvent system, and more specifically, using a heptane mixed solvent system consisting of paraffinic heptane and naphthic heptane as a solution polymerization solvent. The present invention relates to a method for producing a conjugated diene polymer prepared by homopolymerizing a conjugated diene monomer in the presence of a lithium polymerization initiator or copolymerizing a conjugated diene monomer and a vinyl aromatic monomer.

Polymerization methods for producing conjugated diene polymers are roughly classified into emulsion polymerization and solution polymerization. The emulsion polymerization method polymerizes the monomers through free radical reaction in water in the presence of an initiator, and the solution polymerization method polymerizes the monomers through anionic polymerization in an organic solvent. Due to global regulations on carbon dioxide due to high oil prices and environmentally friendly policies, we prefer solution polymerization products with excellent wet resistance and rolling resistance properties instead of emulsion polymerization products. have.

In general, a single solvent such as toluene, cyclohexane, n -hexane and cycloheptane is mainly used as a solvent for anionic solution polymerization. These organic solvents have the advantages of high compatibility with the rubber to be prepared and excellent polymerization activity, resulting in a fast reaction rate and a narrow molecular weight distribution of the produced polymer. Toluene as a polymerization solvent tends to increase the polymerization reaction rate compared to other organic solvents, but it is difficult to control the molecular weight and increase the molecular weight distribution due to the chain transfer phenomenon by the toluene solvent during polymerization. In a batch reaction requiring a coupling reaction, sufficient coupling yield cannot be obtained, and thus it is extremely limited to be used as an anionic polymerization solvent. For this reason, cyclohexane or n -hexane is mainly used commercially in the anion polymerization method. In particular, in the case of batch polymerization, cyclohexane or n -hexane can be used to obtain fast reactivity and high coupling efficiency, and have high compatibility with solvents when preparing copolymers with vinylaromatic compounds. Manufacturing is possible. However, in terms of productivity, cyclohexane is disadvantageous in terms of productivity due to high solvent price, high compatibility with rubber, and high solution viscosity of polymer produced due to high specific heat. Since the amount of polymerization is inevitably limited. In addition, since the use of an excessive amount of the polymerization solvent requires a lot of steam and electricity costs for the recovery of the polymerization solvent, it is generally very disadvantageous in terms of productivity compared to the synthetic rubber produced by emulsion polymerization. In the case of n -hexane, there is a disadvantage that the initial investment cost for commercialization process construction is relatively high because the pressure of the reactor increases due to the reaction heat generated during the polymerization process due to the low boiling point of the solvent.

In addition, the conjugated diene-based polymer prepared by the solution polymerization method is too linearly polymerized compared to the emulsion polymerization product, so when stored at room temperature for a long time after production, the cold flow phenomenon easily occurs, and thus the storage stability is inferior. When used as a material, the compound pattern viscosity increases, which has a problem in that workability is degraded.

As described above, due to the regulation of carbon dioxide according to high oil prices and environmentally friendly policies, the development of a new solution polymerization method that can replace the emulsion polymerization method is urgently needed as a method for preparing a conjugated diene polymer. The method for producing conjugated diene-based polymers by solution polymerization, which has been developed so far, has been inferior to conventional emulsion polymerization methods in terms of productivity.

Accordingly, the present inventors have been continually studying a method for preparing a conjugated diene-based polymer by a solution polymerization method, and it has been recognized that selection of a polymerization solvent is very important. According to the study results of the present inventors, when a conjugated diene polymer is prepared by solution polymerization using a mixed solvent system consisting of paraffinic heptane and naphthenic heptane as a polymerization solvent, existing organic solvents such as cyclohexane, n − Compared to the solution polymerization method using hexane and n -heptane as single solvents, the present invention was completed by confirming that not only the physical properties of the product can be significantly improved but also the productivity can be increased.

The present invention improves the storage stability of the polymer at room temperature, and provides a method for preparing a conjugated diene polymer having a high compatibility with inorganic fillers such as carbon black or silica through solution polymerization by deformation of the microstructure. There is a purpose.

In addition, the present invention has another object to provide a use of the conjugated diene-based polymer prepared by the above-mentioned solution polymerization method as a tire material.

The present invention provides a method for preparing a conjugated diene polymer by solution polymerization of a conjugated diene monomer or a mixture of conjugated diene and vinyl aromatic monomers, wherein the heptane mixed solvent consisting of paraffinic heptane and naphthic heptane as the solution polymerization solvent. It is characterized by a method for producing a conjugated diene polymer by solution polymerization under the conditions using the system.

The present invention is a solution polymerization solvent as a conjugated diene by solution polymerization under conditions using a heptane mixed solvent system consisting of 80% to 95% by weight of paraffinic heptane and 5% to 20% by weight of naphthenic heptane. The method of manufacturing a system polymer is characterized by the above-mentioned.

The present invention provides a conjugated diene-based copolymer obtained by solution polymerization of a mixture of conjugated diene-based and vinyl aromatic monomers, wherein the vinyl aromatic monomer is used in the range of less than 50% by weight based on the total monomer weight to prepare a copolymer. The copolymer is characterized by a method for producing a conjugated diene random copolymer having less than 3% by weight of vinylaromatic blocks formed at the end thereof.

In addition, the present invention is characterized by a tire manufacturing material comprising an conjugated diene-based polymer obtained by the above-described manufacturing method and an inorganic filler selected from silica and carbon black.

The method for producing a conjugated diene polymer using the heptane mixed solvent system according to the present invention is expected to have the following effects.

1) The heptane mixed solvent system proposed by the present invention has a higher specific heat compared to hexane solvents, so that the maximum temperature of the polymerization reaction can be lowered, thereby minimizing side reactions, thereby increasing the total amount of the polymer in the solution. It is getting the effect of improving.

2) The heptane mixed solvent system proposed by the present invention can reduce the viscosity of the prepared polymer compared to the conventional polymer solvent by reducing compatibility with the polymer, thereby significantly reducing the amount of the polymer solvent. Even recovery costs are being reduced.

3) The conjugated diene polymer prepared using the heptane mixed solvent system proposed by the present invention has an effect of improving the storage stability because cold flow does not easily occur at room temperature.

4) The conjugated diene-based polymer prepared by using the heptane mixed solvent system proposed by the present invention has excellent compatibility with inorganic fillers such as carbon black or silica to improve compound processability and uniform filler content. It is getting the effect of improving acidity.

5) Compound materials including conjugated diene-based polymers prepared using the heptane mixed solvent system proposed by the present invention have various physical properties such as Shore hardness, tensile strength, 300% modulus, elongation, dynamic properties, and wear. Excellent effect.

In the present invention, in preparing a conjugated diene polymer by solution polymerization, the main technical feature is to use a heptane mixed solvent system composed of paraffinic heptane and naphthic heptane as a polymerization solvent.

The heptane mixed solvent system according to the present invention is composed of paraffinic heptane and naphthic heptane. Paraffinic heptane refers to a straight or crushed hydrocarbon having 7 carbon atoms, for example n- heptane, 2-methylhexane, 3-methylhexane, 3-ethylpentane, 2,3-dimethylpentane, and 3,3 -Dimethylpentane. In addition, naphthonic heptane refers to a cyclic C7 hydrocarbon and includes cycloheptane, methylcyclohexane, ethylcyclopentane, 1,2-dimethylcyclopentane, and 1,3-dimethylcyclopentane.

The heptane mixed solvent system according to the present invention comprises a composition ratio of 80% by weight or more of paraffinic heptane and 20% by weight or less of naphthenic heptane. The heptane mixed solvent system preferably comprises a composition ratio of 80% to 95% by weight of paraffinic heptane and 5% to 20% by weight of naphthenic heptane, and more preferably 80% to 90% by weight of paraffinic heptane. And a composition ratio of 10% to 20% by weight of naphthonic heptane. In constructing the heptane mixed solvent system of the present invention, if the content of paraffinic heptane is less than 80% by weight, the solution viscosity of the solution polymer may not be sufficiently lowered and productivity may be lowered, and compound physical properties may also be lowered. If the content of paratinic heptane is 95% by weight or more, the compound viscosity due to the lowering of the degree of branching of the resulting polymer is increased, making processing difficult and consequently deteriorating physical properties.

In the heptane mixed solvent system according to the present invention, the specific heat is higher than that of the hexane solvent, so the maximum temperature of the polymerization reaction can be lowered, thereby minimizing side reactions, thereby increasing the total amount of the polymer in the solution, thereby improving productivity. . In addition, while the conjugated diene-based polymer prepared by conventional solution polymerization has a linear chain structure, the conjugated diene-based polymer prepared by the method of the present invention has a microstructure in which branch chains are formed in the main chain. Evidence that branched chains of the prepared conjugated diene-based polymers can be easily confirmed by measuring intrinsic viscosity, and the intrinsic viscosity increases as branched chains are produced. 2, the conjugated diene-based polymer prepared by using the heptane mixed solvent system proposed by the present invention has a low intrinsic viscosity compared to the conjugated diene-based polymer prepared by using hexane alone solvent. As a result, it can be seen that the conjugated diene-based polymer prepared in the present invention has produced a branched chain.

The method for producing a conjugated diene polymer by solution polymerization using a heptane mixed solvent system having the characteristics described above will be described in more detail as follows.

Method for producing a conjugated diene polymer of the present invention comprises a two-step process as follows. That is, a conjugated diene monomer alone or a mixture of conjugated diene monomer and vinyl aromatic monomer is used in a solution in the presence of a Lewis base and an organolithium polymerization initiator using a heptane mixed solvent system consisting of paraffinic heptane and naphthic heptane as a polymerization solvent. A first step of combining to obtain a living polymer; And a second step in which the living polymer prepared above is subjected to a coupling reaction in the presence of a coupling agent to obtain a desired conjugated diene-based polymer.

In the production method according to the present invention, a conjugated diene monomer alone or a mixture of conjugated diene and vinyl aromatic monomers is used as the monomer component.

The conjugated diene monomer is a compound having a polyene structure in which a single bond and a double bond are alternately arranged. For example, 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 2-methyl-1 , 3-pentadiene, 2,3-dimethyl-1,3-pentadiene, 2-methyl-3-ethyl-1,3-pentadiene, 2-phenyl-1,3-butadiene and the like. The vinylaromatic monomer is an aromatic compound containing a vinyl group, and may include, for example, styrene, alpha methyl styrene, vinylpyridine, 1-vinylnaphthalene, 2-vinylnaphthalene, and the like. In addition, the vinylaromatic monomer may be a derivative in which an alkyl, cycloalkyl, aryl, aralkyl and arylalkyl group having 12 or less carbon atoms in the aromatic ring is substituted. Examples include 3-methyl styrene, 3,5-diethyl styrene, 4-cyclohexyl styrene, 2,4,6-trimethyl styrene, 4-phenyl styrene, 2-ethyl-4-benzyl styrene, 4,5- Dimethyl-1-vinylnaphthalene, 3,6-di- p -tolyl-1-vinylnaphthalene, 7-decyl-2-vinylnaphthalene, and the like.

In addition, in preparing a conjugated diene copolymer by solution polymerization of a conjugated diene-based and vinyl aromatic monomer mixture, the content of the vinylaromatic monomer included in the total monomer mixture is 50% by weight or less, preferably 1 to 50% by weight. Maintain weight range. When the content of the vinylaromatic monomer exceeds 50% by weight, wear resistance and low exothermic properties of the polymer cannot be expected. In addition, in the case of the conjugated diene-vinylaromatic copolymer, a problem may occur in that the exotherm increases during the dynamic deformation of the copolymer as the content of the vinylaromatic block increases, so that it is necessary to prepare a random copolymer to improve dynamic properties. have. When the conjugated diene-vinylaromatic copolymer is prepared by the preparation method according to the present invention, the random copolymer having the content of the vinylaromatic block in the copolymer is controlled up to 3% by weight due to the stability of the polymerization reaction due to the solvent effect. It is possible to prepare a perfect random copolymer having a vinyl aromatic block content of 0% by weight.

The polymerization initiator used in the solution polymerization of the present invention has been generally used in the anion solution polymerization technology, and any one can be applied as long as it is recognized as having an anionic polymerization action. As a general polymerization initiator, one or two or more selected from alkali metal or organoalkali metal compounds or derivatives thereof may be used. As a specific polymerization initiator, one or two or more organolithium compounds may be used, and more preferably, one or two monoorganolithium compounds may be used. The monoorganolithium compound may be represented by the general formula RLi, wherein R represents an aliphatic, cycloaliphatic or aromatic hydrocarbon group. Examples of such initiators include n- butyllithium, sec -butyllithium, tert -butyllithium, n- decyllithium, eicosillithium, cyclohexyllithium, phenyllithium, 1-naphthyllithium and p- tolyllithium Can be.

In the solution polymerization of the present invention, a Lewis base can be used, and the Lewis base can control the microstructure of the polymer. The Lewis base can be selected from ethers and amines. Such Lewis bases are specifically tetrahydrofuran, N, N, N ', N' -tetramethylethylenediamine (TMEDA), di ( n- propyl) ether, di (isopropyl) ether, di ( n- butyl) Ether, ethyl butyl ether, triethylene glycol, 1,2-dimethoxybenzene, trimethylamine, triethylamine, and the like, preferably tetrahydrofuran, N, N, N ', N'- as a Lewis base. Tetramethylethylenediamine (TMEDA) is used.

The living polymer formed by anionic solution polymerization according to the present invention performs a coupling reaction with a polyvalent coupling agent to prepare a desired polymer.

In this case, one or two or more selected from the metal chloride represented by the following Chemical Formula 1 or the polysiloxane represented by the following Chemical Formula 2 may be used as the coupling agent.

M (R) _m Cl _n

In Formula 1, M represents a metal atom of tin (Sn) or silicon (Si); R represents an alkyl group having 1 to 20 carbon atoms; n + m = 4 and n represents the integer of 1-4.

In Formula 2, X represents a halogen atom; Y represents tin (Si) or carbon (C) atom; R ¹ And R ² is the same as or different from each other, and represents a halogen atom, an alkyl group having 1 to 20 carbon atoms, a haloalkyl group having 1 to 20 carbon atoms, or a silane group substituted with halogen; a + b = 3 and a represents an integer of 1 to 3; c represents an integer from 1 to 1,000; d represents an integer of 1 to 50,000.

Metal chloride represented by the formula (1) used as a coupling agent in the present invention is specifically tin tetrachloride (SnCl ₄ ), C _1-6 alkyl trichloride (SnCl ₃ R), di (C _1-6 alkyl) dichloride Tin chloride tetrachloride (SiCl ₄ ), such as tin (SnCl ₂ R ₂ ), tri (C _1-6 alkyl) tin monochloride (SnClR ₃ ), C _1-6 alkyltrichloride (SiCl ₃ R), di (C It can be selected from silicon chlorides such as _1-6 alkyl) dichloride (SiCl ₂ R ₂ ), tri (C _1-6 alkyl) silicon chloride (SiClR ₃ ). In addition, the polysiloxane represented by Chemical Formula 2 uses a number average molecular weight in the range of 500 to 1500, and specifically, α, ω-bis (2-trichlorosilylethyl) polydimethylsiloxane, α, ω-bis (2- Dichloromethylsilylethyl) polydimethylsiloxane, α, ω-bis (2-chlorodimethylsilylethyl) polydimethylsiloxane can be selected and used. The above-mentioned coupling agent is preferably used in a molar ratio of 0.01 to 0.5 molar ratio based on 1 mole of living polymer in view of reducing heat loss due to elastic hysteresis.

 In addition, the solution polymerization of the present invention is carried out at a temperature range of 10 ℃ to 130 ℃, the conjugated diene polymer prepared by the polymerization method as described above, relative to the conjugated diene system prepared using a conventional polymerization solvent It has a high branched chain structure. In addition, the conjugated diene-based polymer prepared by the polymerization method of the present invention has a pattern viscosity of 20 to 200, weight average molecular weight (Mw) of 100,000 to 1,000,000 range, molecular weight distribution (MWD) of 1.0 to 4.0, The coupling rate is in the range of 10 to 90.

The present invention as described above will be described in more detail based on the following Examples and Experimental Examples.

In the following examples will be described a rubber manufacturing method and blending properties using the mixed organic solvent according to the present invention, the examples described herein are intended to limit the scope of the present invention only for the purpose of illustrating the present invention. It is not provided.

[ Example ]

Examples 1 and 2 and Comparative Examples 1 to 5

After supplying 3400 g of the polymerization solvent shown in Table 1 to the 10 L stainless reactor, 0.80 g of N, N, N ', N' -tetramethylethylenediamine (TMEDA), 119 g of styrene and 436 g of butadiene were added together. Was put into. When the addition was completed, the reactor internal temperature was adjusted to 35 ° C. while turning the stirrer. When the reactor temperature reached the set temperature, 4.0 mmol of n- butyllithium was added to the reactor to perform an adiabatic heating reaction. When the reaction temperature reached the maximum temperature, 12 g of 1,3-butadiene was further added to replace the reaction terminal with butadiene. When the additional butadiene supply was completed, the α, ω-bis (2-trichlorosilylethyl) polydimethylsiloxane having a number average molecular weight (Mn) of 1,345 was diluted as a coupling agent, 1.08 g was fed to the reactor, and the coupling reaction was performed for 30 minutes. Proceeded. Then, 2.4 g of butylhydroxytoluene (BHT) was added as an antioxidant into the reactor.

[ Experimental Example ]

Experimental Example 1. Physical and chemical properties of conjugated diene polymer

The conjugated diene-based polymers prepared by the methods of Examples 1 and 2 and Comparative Examples 1 to 5 are shown in Table 2 by measuring the physicochemical properties in the following manner.

1) Microstructure

The microstructure of the polymer was confirmed by nuclear magnetic resonance analysis (400 MHz NMR), and the formation of branch chains bound to the main chain was compared by comparing the intrinsic viscosity values of each polymer measured using a Viscotek Model 302 instrument. The degree of branch chain formation was compared.

2) viscosity

The solution viscosity for the pre-polymer formulation was measured at 63 ° C. and 6 rpm using a Brookfield viscometer (Spindle type S64r). After the completion of the polymerization, the pattern viscosity of the polymer and the reaction mixture after removing the solvent was measured using a pattern viscosity meter.

3) molecular weight, coupling rate

The weight average molecular weight (Mw), molecular weight distribution (MWD), coupling number, and coupling ratio of the prepared polymer were measured using GPC.

4) Cold Flowability

In order to confirm the storage stability at room temperature, it was measured by using a cold flow meter at 50 ℃ using a convection vacuum oven (convection vacuum oven). The measurement method is as follows. A cold flow meter (COLD FLOW TESTER) was placed in an oven (50 ± 1 ° C.) for about 30 minutes to achieve temperature equilibrium, and about 1.5 g of rubber sample was added. The cold flow meter was tightened and loosened by turning it back about 1/8 of a turn (about 45 °). Some rubber was pressed out of the meter and the released rubber was cut with a razor. Immediately after this, the meter and stand were placed in the oven and the cold flow was measured.

According to the results of Table 2, the conjugated diene polymer (Examples 1 and 2) prepared using the heptane mixed solvent system according to the present invention had the highest polymerization reaction compared with the case of the solvent used in Comparative Examples 1 to 5. Since the temperature is low and the solution viscosity is remarkably low compared to Comparative Examples 1, 2 and 5, the polymerization can be carried out using a small amount of solvent when applied to a commercial process. That is, in Comparative Examples 1, 2, and 5, the reaction rate is fast and the reaction maximum temperature is high, so that the reaction proceeds rapidly, but many styrene blocks are formed at the end portion of the polymer. The reaction rate is also gentle, resulting in a random copolymer with a low content of styrene blocks. Therefore, the present invention can produce a larger amount of product because the reaction maximum temperature is relatively low compared to the conventional method, it is possible to obtain the effect of increasing productivity and solvent recovery cost at the same time.

In addition, the conjugated diene-based polymer (Examples 1 and 2) prepared by the method of the present invention is a strain of the microstructure in which branch chains are formed, and thus, cold flow at room temperature does not easily occur, thereby improving storage stability. I am getting the effect to let. On the contrary, in the case of Comparative Examples 1 to 5, the linearity of the polymer was increased and the cold flow property was increased. As a result, the storage stability was relatively lower than that of the conjugated diene polymer of the present invention. have.

Experimental Example 2. Confirmation of compatibility with inorganic filler components

In the present experimental example, the experiment was conducted in the following manner to confirm the degree of compatibility with the inorganic filler for the conjugated diene-based polymer prepared by the method of Example 1 and Comparative Examples 1 to 5.

1) Experimental Method:

100 g of the conjugated diene-based polymer prepared in Examples 1 and Comparative Examples 1 to 5, respectively, was blended into the inorganic filler shown below to measure blending processability and physical and dynamic properties after blending.

① Composition of silica inorganic filler

2 g of stearic acid, 3 g of ZnO, 50 g of silica (Zeosil # 175), 10 g of aromatic oil, 4 g of bis (triethoxysilylpropyl) tetrasulfane (Si-69), N- cyclohexylbenzothiazole-2 -Sulfenamide (CZ) 2 g, 1,3-diphenyl guanidine (DPG) 2 g, sulfur 1.6 g

② Composition of carbon black inorganic filler

50 g of carbon black (normal 330), 1 g of stearic acid, 3 g of ZnO, 1 g of N- (1,1-dimethylethyl) -2-benzothiazolesulfonamide, 1.75 g of sulfur

③ Composition of silica-carbon black mixed inorganic filler

20 g of silica (# 175), 30 g of carbon black (normal 330), 2 g of stearic acid, 3 g of ZnO, 18 g of aromatic oil, 1.6 g of bis (triethoxysilylpropyl) tetrasulfane (Si-69), N -cyclohexyl-2-benzothiazole sulfene amide (CZ) 2 g, 1,3- diphenyl guanidine (DPG) 2 g, 1.5 g of sulfur

2) Property measurement method

Hardness was measured using a Shore-A hardness tester. Tensile strength, 300% modulus and elongation of the compounded rubber were measured using a universal testing machine (UTM) according to ASTM 3189 Method B method. Tanδ value, which is a dynamic property value of the vulcanized rubber, was analyzed under a strain condition of 10 Hz and 0.1% using a DMTA 5 instrument of Rheometric. The measured physical properties and dynamic property results are shown in Tables 3 to 5, respectively.

In addition, the dispersion degree of the conjugated diene-based polymer and silica filler of Example 1 and Comparative Example 2 was analyzed using AFM (Atomic Force Microscope), and the results are attached as FIG. Comparing the AFM photograph of Figure 1, the conjugated diene polymer of Example 1 prepared using a heptane mixed solvent system according to the present invention, the conjugated diene polymer of Comparative Example 2 prepared using a cyclohexane solvent In comparison, it can be confirmed that the dispersibility of the silica filler is better.

When comparing Example 1 and Comparative Examples 1 to 5 of the present invention, since the compound pattern viscosity, which is a workable railway, is the lowest in Example 1, it can be seen that the workability is excellent, and in the case of dynamic characteristics, 10 shows a slip resistance. The highest tan delta value indicates the excellent stable physical properties, the lowest 60 탄 tan delta value representing the rolling resistance is excellent in low fuel consumption performance, the wear resistance also showed that the best in Example 1.

Experimental Example 3. Intrinsic Viscosity Measurement

 Each of the conjugated diene-based polymers obtained according to Example 1 and Comparative Example 2 was compared with the intrinsic viscosity values measured using the Viscotek model 302 device to compare the degree of generation of the branch chains, and the results are shown in FIG. 2.

According to the results of FIG. 2, the conjugated diene-based polymer of Example 1 prepared according to the present invention had an intrinsic viscosity value of 2.3, and the conjugated diene-based polymer prepared in Comparative Example 2 had an intrinsic viscosity value of 2.5. As a result, it was found that the conjugated diene polymer prepared using the heptane mixed solvent according to the present invention contained a higher content of branched chains than the conjugated diene polymer prepared using a cyclohexane solvent.

 As described above, when the conjugated diene-based polymer is prepared using the heptane mixed solvent system proposed by the present invention, the solution viscosity of the prepared polymer is significantly lowered, which can drastically reduce the amount of the solvent used for the polymerization. In addition, the amount of polymerization per hour can be increased, and ultimately, the productivity can be expected to be increased by up to 40% or more compared to the method using the conventional organic solvent.

In addition, when using the conjugated diene-based polymer prepared by the manufacturing method of the present invention as a tire material, the dispersibility and compatibility for inorganic fillers such as silica or carbon black is significantly increased compared to the conventional tire material, silica tire The wear resistance required for the motors also increases performance and high mechanical properties, ultimately increasing tire durability. In particular, wetting resistance is improved compared to conventional tires, which reduces the stopping distance, which is advantageous in terms of safety.

1 is an atomic force microscope (AFM) photograph of a compound comprising a conjugated diene-based polymer and a silica inorganic filler,

a) is a styrene-butadiene copolymer (Example 1) prepared using a heptane mixed solvent system (m-HPT) having a content ratio of paraffinic heptane and naphthonic heptane (90/10, wt%). AFM picture of the formulation included,

b) is an AFM photograph of a blend containing styrene-butadiene copolymer (Comparative Example 2) prepared using cyclohexane (CHX) monosolvent.

2 is a styrene-butadiene copolymer (Example 1) prepared using a heptane mixed solvent system having a content ratio of paraffinic heptane and naphthonic heptane (90/10, wt%), and a cyclohexane sole solvent; It is a graph comparing the intrinsic viscosity measurement of the styrene-butadiene copolymer (Comparative Example 2) prepared using.

The top of the graph is the intrinsic viscosity value of the styrene-butadiene copolymer prepared using a solvent of cyclohexane.

Claims (9)

In the method for producing a conjugated diene polymer by solution polymerization of a conjugated diene monomer or a mixture of conjugated diene and vinyl aromatic monomers, The solution polymerization solvent is a conjugated solution solution by using a heptane mixed solvent system consisting of paraffinic heptanes having 7 straight-chain or crushed carbon atoms and naphthonic heptanes having 7 cyclic carbon atoms. Method for producing a diene polymer. The method of claim 1, The solution polymerization solvent is a conjugated diene system by solution polymerization, characterized in that heptanes mixed solvent system consisting of 80% to 95% by weight of paraffinic heptane and 5% to 20% by weight of naphthenic heptane. Method of Making Polymers. The method of claim 2, The paraffinic heptane is a single or a mixture of two or more selected from the group consisting of n- heptane, 2-methylhexane, 3-methylhexane, 3-ethylpentane, 2,3-dimethylpentane, and 3,3-dimethylpentane, The naphthenic heptane is conjugated by solution polymerization, characterized in that it is a single or mixture of two or more selected from cycloheptane, methylcyclohexane, ethylcyclopentane, 1,2-dimethylcyclopentane, and 1,3-dimethylcyclopentane. Method for producing a diene polymer.  The method of claim 1, The conjugated diene-based monomer is a method for producing a conjugated diene-based polymer by solution polymerization, characterized in that selected from the group consisting of 1,3-butadiene, isoprene, and mixtures thereof.  The method of claim 1, The vinyl aromatic monomer is a method for producing a conjugated diene polymer by solution polymerization, characterized in that selected from the group consisting of styrene, alpha methyl styrene and mixtures thereof. The method of claim 1, The vinylaromatic monomer is a method for producing a conjugated diene-based polymer by solution polymerization, characterized in that used in the range of 1% by weight to 50% by weight based on the total monomer weight. The method of claim 1, A method for producing a conjugated diene polymer, characterized in that for producing a random copolymer having a vinyl aromatic block content of up to 3% by weight in the polymer. The method of claim 1, The prepared polymer has a pattern viscosity of 20 to 200, a weight average molecular weight (Mw) of 100,000 to 1,000,000, a molecular weight distribution (MWD) of 1.0 to 4.0, the coupling ratio of 10 to 90 to prepare a conjugated diene polymer by solution polymerization Way.  A tire material comprising a conjugated diene-based polymer prepared by the method of any one of claims 1 to 8 in a tire manufacturing material containing an inorganic filler selected from silica and carbon black.

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