Modified conjugated diene copolymer

Abstract

The present invention relates to a modified conjugated diene copolymer that, when applied to a rubber composition, exhibits a good balance of wet skid resistance and rolling resistance, and provides a modified conjugated diene copolymer that contains first polymer units, second copolymer units, and a functional group derived from a modifier, and that satisfies the conditions (i) to (vi).

Description

[Technical Field]

[0001] This application claims the benefit of priority based on Korean Patent Application No. 10-2022-0137475, filed on October 24, 2022, and all contents disclosed in the documents of this Korean patent application are incorporated herein by reference.

[0002] The present invention relates to a modified conjugated diene copolymer that, when used in a rubber composition, exhibits a good balance of wet skid resistance and rolling resistance. [Background technology]

[0003] In recent years, with the demand for improved fuel economy in automobiles, there has been a demand for conjugated diene polymers as rubber materials for tires that have low rolling resistance, excellent abrasion resistance and tensile properties, as well as adjustment stability, as typified by wet skid resistance.

[0004] One method for reducing the running resistance of a tire is to reduce the hysteresis loss of vulcanized rubber, and the evaluation indexes for such vulcanized rubber include rebound resilience, tan δ, Goodrich heat generation, etc. at 50°C to 80°C. That is, a rubber material that has high rebound resilience or low tan δ and Goodrich heat generation at the above temperatures is preferred.

[0005] Known rubber materials with low hysteresis loss include natural rubber, polyisoprene rubber, and polybutadiene rubber. However, these materials suffer from poor wet skid resistance. Therefore, conjugated diene polymers or copolymers, such as styrene-butadiene rubber (SBR) or butadiene rubber (BR), have recently been produced by emulsion polymerization or solution polymerization and used as tire rubber. The greatest advantage of solution polymerization over emulsion polymerization is its ability to freely adjust the vinyl and styrene content, which determine the rubber's physical properties, and its ability to control molecular weight and physical properties through coupling and modification. Therefore, solution-polymerized SBR is widely used as a tire rubber material because the final SBR or BR can be easily modified, and chain end bonding or modification can reduce chain end movement and increase the bonding strength with fillers such as silica or carbon black.

[0006] The solution-polymerized SBR is produced using an anionic polymerization initiator, and a technique is used in which the chain ends of the formed polymer are bonded or modified with various modifiers to introduce functional groups to the ends. For example, U.S. Patent No. 4,397,994 proposes a technique in which active anions at the chain ends of a polymer obtained by polymerizing styrene-butadiene in a nonpolar solvent using a monofunctional initiator, an alkyllithium, are bonded with a bonding agent such as a tin compound.

[0007] Furthermore, when the solution-polymerized SBR is used as a rubber material, the physical properties required for a tire, such as rolling resistance, can be adjusted by increasing the vinyl content in the SBR, but a high vinyl content can lead to poor braking performance and abrasion resistance. Therefore, the styrene content in the SBR must be maintained at a certain level or higher, but in this case, the effects achieved by a high vinyl content are not achieved.

[0008] Therefore, attempts were made to improve the rolling resistance and wet skid resistance in a balanced manner by using a block copolymer SBR containing two block copolymer units with a gradient in the styrene and vinyl content as the solution-polymerized SBR, but the improvement was minimal. [Prior art documents] [Patent documents]

[0009] [Patent Document 1] JP 8-193147 [Patent Document 2] US4,397,994A Summary of the Invention [Problem to be solved by the invention]

[0010] The present invention has been made to solve the above-mentioned problems of the conventional art, and has an object to provide a modified conjugated diene-based copolymer that satisfies specific conditions and includes first polymer units and second copolymer units, each of which contains a repeating unit derived from a conjugated diene-based monomer, or a repeating unit derived from a conjugated diene-based monomer and a repeating unit derived from an aromatic vinyl-based monomer, and a functional group derived from a modifier. [Means for solving the problem]

[0011] According to one embodiment of the present invention for solving the above-mentioned problems, the present invention provides a modified conjugated diene-based copolymer comprising first polymer units, second copolymer units, and a functional group derived from a modifier, wherein the first polymer units comprise repeating units derived from a conjugated diene-based monomer, and the second copolymer units comprise repeating units derived from the conjugated diene-based monomer and repeating units derived from an aromatic vinyl-based monomer, and the modified conjugated diene-based copolymer satisfies the following conditions (i) to (vi): (i) In accordance with ISO22768:2006, the differential scanning calorimetry curve measured using a differential scanning calorimetry (DSC) meter while heating from -100°C to 100°C at a rate of 10°C / min under a nitrogen flow of 50 ml / min shows two peaks; (ii) the glass transition temperature of the first polymer unit is lower than the glass transition temperature of the second copolymer unit; (iii) the glass transition temperature of the first polymer unit is −100° C. to −40° C., (iv) the glass transition temperature of the second copolymer unit is higher than −40° C. and not higher than 10° C.; (v) the content of the second copolymer unit is 5% by weight to 40% by weight; (vi) The interaction parameter (X) defined by the following mathematical formula 1 at room temperature eff N) is 15 or more, [Mathematical formula 1] X eff N=[(x1-x2)(y2-y1)(X VS -X BS )+(y1-y2) 2 X VB ]×N In the above mathematical formula 1, N is the degree of polymerization of the modified conjugated diene copolymer, x1 is the volume ratio of styrene bonds in the first polymer, x2 is the volume ratio of styrene bonds in the second copolymer, y1 is the volume ratio of 1,2-vinyl bonds in butadiene in the first polymer, y2 is the volume ratio of 1,2-vinyl bonds in the butadiene in the second copolymer, X VS is 0.0565+5.62T -1 and X BS is 0.00843+10.2T -1 and X VB is 0.00269+1.87T -1 where T is room temperature and the unit is absolute temperature (K). [Effects of the Invention]

[0012] The modified conjugated diene copolymer according to the present invention contains first polymer units, second copolymer units, and functional groups derived from a modifier, and satisfies the specific conditions defined in (i) to (vi), and therefore has the effect of improving both wet skid resistance and rolling resistance when applied to a rubber composition. DETAILED DESCRIPTION OF THE INVENTION

[0013] The present invention will now be described in more detail so that the present invention may be more easily understood.

[0014] The terms and words used in the description of the present invention and the claims should not be interpreted in a limited way to their ordinary or dictionary meanings, but should be interpreted in a way that is consistent with the technical idea of ​​the present invention, based on the principle that the inventors can appropriately define the concepts of terms in order to best describe their invention.

[0015] definition As used herein, the term "copolymer" refers to a polymeric compound prepared by polymerizing two or more different types of monomers.

[0016] As used herein, the term "1,2-vinyl bond content" refers to the mass (or weight) percentage of butadiene contained in the 1,2-positions in the polymer chain of a copolymer, based on the portion derived from a conjugated diene monomer (such as butadiene) in the copolymer (the total amount of polymerized butadiene).

[0017] As used herein, the term "styrene bond content" refers to the mass (or weight) percentage of styrene contained in the copolymer chain of the copolymer, which is derived from an aromatic vinyl monomer (such as styrene) in the copolymer.

[0018] As used herein, the term "interaction parameter (X effThe "effective interaction parameter (or effective segmental interaction parameter), which is a measure of the interaction between the structural units of a copolymer, multiplied by the degree of polymerization of the copolymer, is calculated using mathematical formula 1, which is the well-known Flory-Huggins Interaction parameter calculation formula (see Marcromolecules 1991, 24, 4844-4851 and RSC Advances, 2016, 6, 50460-50470).

[0019] [Mathematical formula 1] X eff N=[(x1-x2)(y2-y1)(X VS -X BS )+(y1-y2) 2 X VB ]×N

[0020] In the above mathematical formula 1, N is the degree of polymerization of the modified conjugated diene copolymer, x1 is the volume ratio of styrene bonds in the first polymer, x2 is the volume ratio of styrene bonds in the second copolymer, y1 is the volume ratio of 1,2-vinyl bonds in butadiene in the first polymer, y2 is the volume ratio of 1,2-vinyl bonds in the butadiene in the second copolymer, X VS is 0.0565+5.62T -1 and X BS is 0.00843+10.2T -1 and X VB is 0.00269+1.87T -1 where T is room temperature and the unit is absolute temperature (K).

[0021] Here, T stands for unit, which is the absolute temperature unit (K).

[0022] The volume ratios of 1,2-vinyl bonds and styrene bonds in the copolymer were values ​​obtained by measurement and analysis using a Varian VNMR 500 MHz NMR. Specifically, 1,1,2,2-tetrachloroethane was used as the solvent during measurement, the solvent peak was calculated to be 5.97 ppm, and the volume ratios of styrene bonds and 1,2-vinyl bonds were calculated using the peaks of random styrene from 7.2 to 6.9 ppm, block styrene from 6.9 to 6.2 ppm, 1,4-vinyl bonds from 5.8 to 5.1 ppm, and 1,2-vinyl bonds from 5.1 to 4.5 ppm.

[0023] In this specification, the term "room temperature" means a temperature in its natural state without heating or cooling, and is a temperature of 25±5°C. In the mathematical formula 1 of the present invention, it can be applied as 293K to 303K using the absolute temperature unit (K).

[0024] As used herein, the term "substituted" means that hydrogen atoms of a functional group, atomic group, or compound are substituted with a specific substituent. When hydrogen atoms of a functional group, atomic group, or compound are substituted with a specific substituent, one or more substituents may be present depending on the number of hydrogen atoms present in the functional group, atomic group, or compound. When multiple substituents are present, the respective substituents may be the same or different.

[0025] As used herein, the term "alkyl group" means a monovalent aliphatic saturated hydrocarbon, and may be intended to include any of straight-chain alkyl groups such as methyl, ethyl, propyl, and butyl; branched alkyl groups such as isopropyl, sec-butyl, tert-butyl, and neo-pentyl; and cyclic saturated hydrocarbons or cyclic unsaturated hydrocarbons containing one or more unsaturated bonds.

[0026] As used herein, the term "alkylene group" may refer to a divalent aliphatic saturated hydrocarbon such as methylene, ethylene, propylene, and butylene.

[0027] In the present invention, the term "cycloalkyl group" may mean a cyclic saturated hydrocarbon.

[0028] As used herein, the term "aryl group" refers to an aromatic hydrocarbon and can include both monocyclic aromatic hydrocarbons, in which one ring is formed, and polycyclic aromatic hydrocarbons, in which two or more rings are linked together.

[0029] As used herein, the term "aralkyl" is also known as aralkyl, and may refer to a combination of an alkyl group and an aryl group formed by substituting a hydrogen atom bonded to a carbon atom constituting an alkyl group with an aryl group.

[0030] As used herein, the term "single bond" may refer to a single covalent bond itself, without involving another atom or molecular group.

[0031] As used herein, the terms "derived unit," "derived repeating unit," and "derived functional group" can refer to a component or structure originating from a certain substance, or the substance itself.

[0032] As used herein, the terms "comprising," "having," and their derivatives are not intended to exclude the presence of any additional component, step, or procedure, whether specifically disclosed or not. To avoid any uncertainty, all compositions claimed by the use of the term "comprising" may include any additional additives, adjuvants, or compounds, whether polymeric or otherwise, unless stated to the contrary. In contrast, the term "consisting essentially of" excludes from the scope of any sequential description any other component, step, or procedure, except those that are not essential for operability. The term "consisting of" excludes any component, step, or procedure not specifically stated or listed.

[0033] Measurement method and conditions In this specification, the "content of 1,2-vinyl bonds" and "content of styrene bonds" refer to the vinyl and styrene contents measured and analyzed in the copolymer and the first and second copolymer units using a Varian VNMRS 500 MHz NMR. During NMR measurement, 1,1,2,2-tetrachloroethane was used as the solvent, and the solvent peak was calculated to be 6.0 ppm. The peaks for random styrene were 7.2 to 6.9 ppm, block styrene 6.9 to 6.2 ppm, 1,4-vinyl and 1,2-vinyl 5.8 to 5.1 ppm, and 1,2-vinyl 5.1 to 4.5 ppm. The contents of 1,2-vinyl bonds and styrene bonds in the whole polymer were calculated and measured, respectively.

[0034] In this specification, the terms "weight average molecular weight (Mw)," "molecular weight distribution (MWD)," and "unimodal characteristics" are determined by measuring molecular weights using gel permeation chromatograph (GPC) analysis and obtaining molecular weight distribution curves. The molecular weight distributions (PDI, MWD, and Mw / Mn) are calculated from the measured molecular weights. Specifically, the GPC is performed using a combination of two PLgel Olexis (Polymer Laboratories) columns and one PLgel mixed-C (Polymer Laboratories) column, and PS (polystyrene) is used as the GPC standard material when calculating molecular weights. The GPC measurement solvent is prepared by mixing 2 wt. % of an amine compound in tetrahydrofuran.

[0035] In this specification, the "glass transition temperature (Tg)" is determined in accordance with ISO22768:2006 by recording a differential scanning calorimetry curve (DSC curve) using a differential scanning calorimetry (DSCQ100, manufactured by TA Corporation) while raising the temperature from -100°C at a rate of 10°C / min under a nitrogen flow of 50 ml / min, and the peak top (inflection point) of the DSC differential curve is defined as the glass transition temperature.

[0036] In this specification, the "Si content" is measured using an inductively coupled plasma optical emission spectrometer (ICP-OES; Optima 7300DV) as an ICP analysis method. Using the inductively coupled plasma optical emission spectrometer, approximately 0.7 g of a sample was placed in a platinum crucible, and approximately 1 mL of concentrated sulfuric acid (98 wt %, electronic grade) was added and heated at 300°C for 3 hours. The sample was then ashed in an electric furnace (Thermo Scientific, Lindberg Blue M) according to the following program of steps 1 to 3, and then: 1) Step 1: initial temp 0℃, rate(temp / hr) 180℃ / hr, temp(holdtime) 180℃(1hr); 2) Step 2: initial temp 180℃, rate(temp / hr) 85℃ / hr, temp(hold time) 370℃(2hr); 3) Step 3: initial temp 370℃, rate(temp / hr) 47℃ / hr, temp(hold time) 510℃(3hr); To the residue, add 1 mL of concentrated nitric acid (48 wt%) and 20 μL of concentrated hydrofluoric acid (50 wt%), seal the platinum crucible and shake for more than 30 minutes. Then, add 1 mL of boric acid to the sample and store at 0°C for more than 2 hours. Then, dilute with 30 mL of ultrapure water, incinerate and measure.

[0037] As used herein, "nitrogen content" can be measured by NSX analysis. The NSX analysis is performed using an ultratrace nitrogen analyzer (NSX-2100H). Specifically, the ultratrace nitrogen analyzer (auto sampler, horizontal furnace, PMT & nitrogen detector) is turned on, and the carrier gas flow rates are set to Ar 250 ml / min, O 350 ml / min, and ozonizer 300 ml / min. The heater is set to 800°C, and the analyzer is then allowed to stabilize for approximately three hours. After the analyzer stabilized, a nitrogen standard (AccuStandard S-22750-01-5ml) is used to create calibration curves for the calibration ranges of 5 ppm, 10 ppm, 50 ppm, 100 ppm, and 500 ppm. The area corresponding to each concentration is obtained, and a straight line is then created using the ratio of the concentration to the area. Then, a ceramic boat containing 20 mg of sample is placed in the autosampler of the analyzer and measured to obtain the area. The nitrogen atom content is calculated using the obtained sample area and the calibration curve.

[0038] In this case, the sample used in the NSX analysis method is a modified conjugated diene polymer sample that has been placed in steam-heated hot water and stirred to remove the solvent, and is a sample from which residual monomers and modifiers have been removed. If oil has been added to the sample, the sample is the one from which the oil has been extracted (removed).

[0039] In the present invention, the "shrinkage factor" is calculated based on the solution viscosity and light scattering method by measuring a chromatogram using a gel chromatography-light scattering measurement device equipped with a light scattering detector, an RI detector, and a viscosity detector. Specifically, a GPC-light scattering measurement device (GPCmax VE-2001, Malvern) was used, which is connected in order to a light scattering detector, an RI detector, and a viscosity detector (TDA305, Malvern) to which three columns packed with polystyrene gel are connected. The absolute molecular weight was obtained from the light scattering detector and the RI detector, and the intrinsic viscosity [η] corresponding to the absolute molecular weight was obtained from the RI detector and the viscosity detector. The intrinsic viscosity [η] of the linear polymer corresponding to the absolute molecular weight was then calculated using the following mathematical formula 2. The average value of the ratio of the intrinsic viscosities ([η] / [η]) corresponding to each absolute molecular weight was expressed as the shrinkage factor. In this case, a mixed solution of tetrahydrofuran and triethylamine (THF in TEA: prepared by mixing 5 mmol of triethylamine with 1 L of tetrahydrofuran) was used as the eluent, and a combination of TSKgel G4000HXL (Tosoh Corporation), TSKgel G5000HXL (Tosoh Corporation), and TSKgel G6000HXL (Tosoh Corporation) was used as the column. The sample was prepared by dissolving 20 mg of polymer in 10 mL of THF, and 100 μL of the measurement solution was injected into the GPC measurement device and measured under conditions of an oven temperature of 40°C and a THF flow rate of 1.0 mL / min.

[0040] [Mathematical formula 2] [η]0=10 -3.883 M 0.771

[0041] In the above mathematical formula 2, M is the absolute molecular weight.

[0042] Modified conjugated diene copolymer The modified conjugated diene copolymer according to the present invention comprises first polymer units, second copolymer units, and a functional group derived from a modifier, the first polymer units comprising repeating units derived from a conjugated diene monomer, and the second copolymer units comprising repeating units derived from a conjugated diene monomer and repeating units derived from an aromatic vinyl monomer, and is characterized by satisfying the following conditions (i) to (vi): (i) In accordance with ISO22768:2006, the differential scanning calorimetry curve measured using a differential scanning calorimetry (DSC) meter while heating from -100°C to 100°C at a rate of 10°C / min under a nitrogen flow of 50 ml / min shows two peaks; (ii) the glass transition temperature of the first polymer unit is lower than the glass transition temperature of the second copolymer unit; (iii) the glass transition temperature of the first polymer unit is −100° C. to −40° C., (iv) the glass transition temperature of the second copolymer unit is higher than −40° C. and not higher than 10° C.; (v) the content of the second copolymer unit is 5% by weight to 40% by weight; (vi) The interaction parameter (X) defined by the following mathematical formula 1 at room temperature eff N) is 15 or more, [Mathematical formula 1] X eff N=[(x1-x2)(y2-y1)(X VS -X BS )+(y1-y2) 2 X VB ]×N In the above mathematical formula 1, N is the degree of polymerization of the modified conjugated diene copolymer, x1 is the volume ratio of styrene bonds in the first polymer, x2 is the volume ratio of styrene bonds in the second copolymer, y1 is the volume ratio of 1,2-vinyl bonds in butadiene in the first polymer, y2 is the volume ratio of 1,2-vinyl bonds in the butadiene in the second copolymer, X VS is 0.0565+5.62T-1 and X BS is 0.00843+10.2T -1 and X VB is 0.00269+1.87T -1 where T is room temperature and the unit is absolute temperature (K).

[0043] According to one embodiment of the present invention, the modified conjugated diene copolymer contains first polymer units, second copolymer units, and functional groups derived from a modifier, and satisfies conditions (i) to (vi), thereby exhibiting excellent mechanical properties such as tensile properties and viscoelasticity. As a result, when applied to a rubber composition, the modified conjugated diene copolymer exhibits excellent and balanced wet skid resistance and rolling resistance.

[0044] Specifically, the modified conjugated diene copolymer has an interaction parameter (X eff N) is 15 or more, specifically, the interaction parameter (X eff N) may be 18 or more. In this case, when applied to a rubber composition, wet skid resistance and rolling resistance can be well balanced and excellent, and steering performance can also be improved.

[0045] On the other hand, the modified conjugated diene copolymer according to one embodiment of the present invention contains first polymer units, second copolymer units, and functional groups derived from a modifier, and satisfies the above-mentioned conditions (i) to (v), and the interaction parameter is in the above-mentioned range or more, so that the object of the present invention can be achieved. Therefore, although the upper limit is not particularly limited, the lower limit of 15 or more should be satisfied in order to achieve the object.

[0046] Here, the interaction parameter (X eff N) is a parameter that measures the interaction determined by the microstructure (1,2-vinyl bonds and styrene bonds) in the copolymer, and can be adjusted by the ratio of the first polymer unit and the second copolymer unit contained in the copolymer and the respective microstructures of the first polymer unit and the second copolymer unit.

[0047] Furthermore, the modified conjugated diene-based copolymer according to one embodiment of the present invention has two peaks in the differential curve measured by a differential scanning calorimeter. Here, the peaks in the differential curve measured by the differential scanning calorimeter represent glass transition temperatures, i.e., the copolymer has two glass transition temperatures, and the peaks in the differential curve of the differential scanning calorimeter representing these glass transition temperatures are distinct. As another example, the modified conjugated diene-based copolymer includes a first polymer unit and a second copolymer unit, and the first polymer unit and the second copolymer unit have different glass transition temperatures, so that the modified conjugated diene-based copolymer has two glass transition temperatures.

[0048] Meanwhile, the first polymer unit may be a first polymer block containing repeating units derived from a conjugated diene monomer, and the second copolymer unit may be a second copolymer block containing repeating units derived from a conjugated diene monomer and repeating units derived from an aromatic vinyl monomer. Here, the second copolymer unit may be a random copolymer, and the random copolymer means a copolymer in which the repeating units constituting the copolymer are arranged in a random manner.

[0049] In one embodiment of the present invention, the first polymer unit may further include a repeating unit derived from an aromatic vinyl monomer, if necessary. In this case, the first copolymer unit may be a copolymer block including a repeating unit derived from a conjugated diene monomer and a repeating unit derived from an aromatic vinyl monomer, and the copolymer block may be a random copolymer.

[0050] The repeating unit derived from the conjugated diene monomer may mean a repeating unit formed by the conjugated diene monomer during polymerization, and the repeating unit derived from the aromatic vinyl monomer may mean a repeating unit formed by the aromatic vinyl monomer during polymerization.

[0051] According to one embodiment of the present invention, the conjugated diene monomer may be at least one selected from the group consisting of 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, piperylene, 3-butyl-1,3-octadiene, isoprene, 2-phenyl-1,3-butadiene, and 2-halo-1,3-butadiene (halo means a halogen atom).

[0052] The aromatic vinyl monomer may be, for example, one or more selected from the group consisting of styrene, α-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 1-vinylnaphthalene, 4-cyclohexylstyrene, 4-(p-methylphenyl)styrene, and 1-vinyl-5-hexylnaphthalene.

[0053] As another example, the first polymer unit and the second copolymer unit may each be a copolymer further comprising, in addition to repeating units derived from a conjugated diene monomer, repeating units derived from a diene monomer having 1 to 10 carbon atoms. The repeating units derived from the diene monomer are repeating units derived from a diene monomer different from the conjugated diene monomer, and the diene monomer different from the conjugated diene monomer may be, for example, 1,2-butadiene. When the first and second copolymer units are each a copolymer further comprising a diene monomer, the repeating units derived from the diene monomer may be greater than 0% by weight to 1% by weight, greater than 0% by weight to 0.1% by weight, greater than 0% by weight to 0.01% by weight, or greater than 0% by weight to 0.001% by weight. Within these ranges, gel formation is effectively prevented.

[0054] The glass transition temperature of the first polymer unit may be -100°C to -40°C, specifically -95°C to -50°C, and the glass transition temperature of the second copolymer unit may be greater than -40°C and 10°C or less, specifically -30°C to 0°C.

[0055] In addition, the glass transition temperature of the first polymer unit may be lower than that of the second copolymer unit, specifically, the glass transition temperature of the second copolymer unit may be 40° C. to 120° C. or 50° C. to 100° C. higher than that of the first polymer unit. In this case, the modified conjugated diene-based copolymer including the first polymer unit and the second copolymer unit may have excellent and balanced wet skid resistance and rolling resistance.

[0056] In addition, the glass transition temperature can be flexibly adjusted depending on the presence or absence of repeating units derived from aromatic vinyl monomers in the first polymer unit and the second copolymer unit, the content of repeating units derived from aromatic vinyl monomers, and the microstructure (content of 1,2-vinyl bonds and content of styrene bonds) in each unit depending on the polymerization method and polymerization conditions.

[0057] For example, the first polymer units may contain 0% to 30% by weight, specifically 0% to 15% by weight, of repeating units derived from an aromatic vinyl monomer. Here, the first polymer units containing 0% by weight of repeating units derived from an aromatic vinyl monomer means that they contain no repeating units derived from an aromatic vinyl monomer. Furthermore, the content of 1,2-vinyl bonds may be 10 to 40 parts by weight per 100 parts by weight of the first polymer units. The second copolymer units may contain more than 0% to 45% by weight of repeating units derived from an aromatic vinyl monomer, and the content of 1,2-vinyl bonds may be 20 to 80 parts by weight per 100 parts by weight of the second copolymer units. Here, the first polymer units and the second copolymer units may have the content of repeating units derived from an aromatic vinyl monomer and the content of 1,2-vinyl bonds adjusted within the aforementioned ranges, respectively, so as to satisfy the above conditions (ii) to (iv). In this case, the abrasion resistance and wet skid resistance are excellent, and the rolling resistance can be improved.

[0058] Meanwhile, the modified conjugated diene copolymer according to one embodiment of the present invention may have a Si and N content of 50 ppm or more, or 50 ppm to 500 ppm, based on the total weight of the copolymer. When the Si and N content are within this range, the rubber composition containing the modified conjugated diene copolymer has excellent mechanical properties such as tensile properties and viscoelastic properties. Meanwhile, the Si and N may be derived from a modifier, which will be described later.

[0059] The modifying agent may be a modifying agent for modifying the terminal of the polymer, and a specific example may be a silica affinity modifying agent. The silica affinity modifying agent refers to a modifying agent containing a silica affinity functional group in the compound used as the modifying agent, and the silica affinity functional group may refer to a functional group that has excellent affinity with a filler, particularly a silica-based filler, and can interact with the silica-based filler and the functional group derived from the modifying agent.

[0060] The modifier may be, for example, an alkoxysilane compound, specifically an alkoxysilane compound containing one or more heteroatoms such as nitrogen, oxygen, or sulfur. When the alkoxysilane compound is used as the modifier, a substitution reaction between an anionic active site at one end of the activated polymer and the alkoxy group of the alkoxysilane compound can modify one end of the activated polymer to a form in which the activated polymer is bonded to a silyl group. This improves the affinity of the modified conjugated diene copolymer containing the first copolymer unit with inorganic fillers, etc., due to the functional group derived from the modifier present at one end of the first copolymer unit, thereby further improving the viscoelasticity of the rubber composition containing the modified conjugated diene copolymer. Furthermore, when the alkoxysilane compound contains a nitrogen atom, in addition to the effect derived from the silyl group, additional physical property improvements derived from the nitrogen atom are expected.

[0061] According to one embodiment of the present invention, the denaturing agent may include a compound represented by the following Chemical Formula 1:

[0062] [ka]

[0063] In the above chemical formula 1, R 5 , R 6 , and R 9 may each independently be an alkylene group having 1 to 10 carbon atoms, and R 7 , R 8 , R 10 , and R 11 may each independently be an alkyl group having 1 to 10 carbon atoms, and R 12 may be a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, b and c may each independently be 0, 1, 2, or 3, and b+c≧1; A may be [ka] wherein R 13 , R 14 , R 15 , and R 16 may each independently be a hydrogen atom or an alkyl group having 1 to 10 carbon atoms.

[0064] As a specific example, the compound represented by Chemical Formula 1 may be one selected from the group consisting of N-(3-(1H-imidazol-1-yl)propyl)-3-(triethoxysilyl)-N-(3-(triethoxysilyl)propyl)propan-1-amine) and 3-(4,5-dihydro-1H-imidazol-1-yl)-N,N-bis(3-(triethoxysilyl)propyl)propan-1-amine.

[0065] As yet another example, the denaturant may include a compound represented by the following Chemical Formula 2:

[0066] [ka]

[0067] In the above chemical formula 2, A 1 and A 2 may each independently be a divalent hydrocarbon group having 1 to 20 carbon atoms, which may or may not contain an oxygen atom; R 17 ~R 20 may each independently be a monovalent hydrocarbon group having 1 to 20 carbon atoms, and L 1 ~L 4 are each independently a mono-, di-, or tri-substituted alkylsilyl group substituted with an alkyl group having 1 to 10 carbon atoms, or a monovalent hydrocarbon group having 1 to 20 carbon atoms; or L 1 and L 2 And, L 3 and L 4 may be linked to each other to form a ring having 1 to 5 carbon atoms, and L 1 and L 2 And, L 3 and L 4 When are linked to each other to form a ring, the ring formed may contain 1 to 3 heteroatoms of one or more kinds selected from the group consisting of N, O, and S.

[0068] As a specific example, in the above-mentioned Chemical Formula 2, A 1 and A 2 may each independently be an alkylene group of 1 to 10 carbon atoms, and R 17 ~R 20 may each independently be an alkyl group having 1 to 10 carbon atoms, and L 1 ~L 4 are each independently a trialkylsilyl group substituted with an alkyl group having 1 to 5 carbon atoms, an alkyl group having 1 to 10 carbon atoms, or L 1 and L 2 And, L 3 and L 4may be linked to each other to form a ring having 1 to 3 carbon atoms, and L 1 and L 2 And, L 3 and L 4 When are linked to each other to form a ring, the ring formed may contain 1 to 3 heteroatoms of one or more kinds selected from the group consisting of N, O, and S.

[0069] More specifically, the compound represented by Chemical Formula 2 may be 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-dimethylpropan-1-amine), 3,3'-(1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(N,N-dimethylpropan-1-amine), or 3,3'-(1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(N,N-dimethylpropan-1-amine). isiloxane-1,3-diyl)bis(N,N-dimethylpropan-1-amine)), 3,3'-(1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(N,N-dimethylpropan-1-amine)), 3,3'-(1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(N,N-dimethylpropan-1-amine)), 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-diethylpropan-1-amine) 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-diethylpropan-1-amine)), 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-dipropylpropan-1-amine)), 3,3'-(1,1,3,3-tetraethoxydisiloxane-1,3-di 3,3'-(1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(N,N-diethylpropan-1-amine), 3,3'-(1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(N,N-diethylpropan-1-amine), 3,3'-(1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(N,N-diethylpropan-1-amine),3,3'-(1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(N,N-dipropylpropan-1-amine), 3,3'-(1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(N,N-dipropylpropan-1-amine) pylpropan-1-amine), 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-diethylmethan-1-amine), 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-diethylmethan-1-amine), 3,3'-(1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(N,N-diethylmethan-1-amine) e-1,3-diyl)bis(N,N-diethylmethan-1-amine)), 3,3'-(1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(N,N-diethylmethan-1-amine)), 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-dimethylmethan-1-amine) 3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-dimethylmethan-1-amine), 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-dipropylmethan-1-amine), 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-dipropylmethan-1-amine)N-dimethylmethan-1-amine) (3,3'-(1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(N,N-dimethylmethan-1-amine)), 3,3'-(1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(N,N-dipropylmethan-1-amine) (3,3'-(1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(N,N-dipropylmethan-1-amine) 3,3'-(1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(N,N-dimethylmethan-1-amine), 3,3'-(1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(N,N-dipropylmethan-1-amine) N,N'-((1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(propan-3,1-diyl))bis(1,1,1-trimethyl-N-(trimethylsilyl)silanamine)), N,N'-((1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(propan-3,1-diyl))bis(1,1,1-trimethyl-N-(trimethylsilyl)silanamine)), N,N'-((1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(propan-3,1-diyl))bis(1,1,1-trimethyl-N-(trimethylsilyl)silanamine)), N,N'-((1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(propan-3,1-diyl))bis(1,1,1-trimethyl-N-(trimethylsilyl)silanamine) (N,N'-((1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(propan-3,1-diyl))bis(1,1,1-trimethyl-N-(trimethylsilyl)silanamine)), N,N'-((1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(propan-3,1-diyl))bis(1,1,1-trimethyl-N-phenylsilanamine) (N,N'-((1,1,3,3-tetra methoxydisiloxane-1,3-diyl)bis(propan-3,1-diyl))bis(1,1,1-trimethyl-N-phenylsilanamine)), N,N'-((1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(propan-3,1-diyl))bis(1,1,1-trimethyl-N-phenylsilanamine) (N,N'-((1,1,3,3-tetraethoxydisiloxane-1,3-diyl)bis(propan-3,1-diyl))bis(1,1,1-trimethyl-N-phenylsilanamine) N,N'-((1,1,3,3-tetrapropoxydisiloxane-1,3-diyl)bis(propan-3,1-diyl))bis(1,1,1-trimethyl-N-phenylsilanamine)), 1,3-bis(3-(1H-imidazol-1-yl)propan-3,1-diyl)bis(1,1,1-trimethyl-N-phenylsilanamine) 1,3-bis(3-(1H-imidazol-1-yl)propyl)-1,1,3,3-tetramethoxydisiloxane, 1,3-bis(3-(1H-imidazol-1-yl)propyl)-1,1,3,3-tetraethoxydisiloxane, and 1,3-bis(3-(1H-imidazol-1-yl)propyl)-1,It may be one selected from the group consisting of 1,3,3-tetrapropoxydisiloxane (1,3-bis(3-(1H-imidazol-1-yl)propyl)-1,1,3,3-tetrapropoxydisiloxane).

[0070] As yet another example, the denaturant may include a compound represented by the following Chemical Formula 3:

[0071] [ka]

[0072] In the above chemical formula 3, R 30 may be a monovalent hydrocarbon group having 1 to 30 carbon atoms, and R 31 ~R 33 may each independently be an alkylene group having 1 to 10 carbon atoms, and R 34 ~R 37 may each independently be an alkyl group having 1 to 10 carbon atoms, g and h may each independently be 0 or an integer selected from 1 to 3, and g+h may be an integer of 1 or greater.

[0073] As yet another example, the denaturant may include a compound represented by the following Chemical Formula 4:

[0074] [ka]

[0075] In the above chemical formula 4, A 3 and A 4 may each independently be an alkylene group of 1 to 10 carbon atoms, and R 38 ~R 41 may each independently be an alkyl group having 1 to 10 carbon atoms or an alkoxy group having 1 to 10 carbon atoms, and i may be an integer selected from 1 to 30.

[0076] As yet another example, the modifier may be 3,4-bis(2-ethoxyethoxy)-N-(4-(trimethylsilyl)butyl)aniline, N,N-diethyl-3-(7-methyl-3,6,8,11-tetraoxa-7-silatridecan-7-yl)propan-1-amine, 2,4-bis(2-methoxyethoxy)-N-(4-(triethoxy ... 2,4-bis(2-methoxyethoxy)-N-(4-(trimethylsilyl)butyl)aniline, 2,4-bis(2-methoxyethoxy)-N-(4-(trimethylsilyl)butyl)aniline, 2,4-bis(2-methoxyethoxy)-N-(4-(trimethylsilyl)butyl)aniline, 2,4-bis(2-methoxyethoxy)-N-(4-(trimethylsilyl)butyl)aniline, 2,4-bis(2-methoxyethoxy)-N-(4-(trimethylsilyl)butyl)aniline, 2,4-bis(2-methoxyethoxy)-N- The compound may comprise one or more selected from the group consisting of 2,4-bis(2-methoxyethoxy)-6-((trimethylsilyl)methyl)-1,3,5-triazine, and 3,14-dimethoxy-3,8,8,13-tetramethyl-2,14-dioxa-7,9-dithia-3,8,13-trisilapentadecane.

[0077] As yet another example, the denaturant may include a compound represented by the following Chemical Formula 5:

[0078] [ka]

[0079] In the above chemical formula 5, R 43 , R 45 , and R 46 may each independently be an alkyl group having 1 to 10 carbon atoms, and R 44 may be an alkylene group having 1 to 10 carbon atoms, and k may be an integer selected from 1 to 4.

[0080] As a more specific example, the compound represented by Chemical Formula 5 is 8,8-dibutyl-3,13-dimethoxy-3,13-dimethyl-2,14-dioxa-7,9-dithia-3,13-disila-8-stannapentadecane ane), 8,8-dimethyl-3,13-dimethoxy-3,13-dimethyl-2,14-dioxa-7,9-dithia-3,13-disila-8-stannapentadecane, 8,8-dibutyl-3,3,13, It may be one selected from the group consisting of 13-tetramethoxy-2,14-dioxa-7,9-dithia-3,13-disila-8-stannapentadecane (8,8-dibutyl-3,3,13,13-tetramethoxy-2,14-dioxa-7,9-dithia-3,13-disila-8-stannapentadecane) and 8-butyl-3,3,13,13-tetramethoxy-8-((3-(trimethoxysilyl)propyl)thio)-2,14-dioxa-7,9-dithia-3,13-disila-8-stannapentadecane.

[0081] In addition, the modified conjugated diene copolymer according to one embodiment of the present invention may have a content of the second copolymer unit of 5% by weight to 40% by weight, specifically 15% by weight to 30% by weight, whereby the glass transition temperature and microstructure of the modified conjugated diene copolymer are appropriately controlled, and the copolymer may have a well-balanced and excellent wet skid resistance and rolling resistance without deterioration of abrasion resistance.

[0082] As another example, the modified conjugated diene copolymer may have a styrene bond content of more than 0% to 25% by weight and a 1,2-vinyl bond content of 10% to 50% by weight, specifically, a styrene bond content of more than 0% to 20% by weight and a 1,2-vinyl bond content of 10% to 30% by weight.

[0083] The styrene bond content and 1,2-vinyl bond content of the modified conjugated diene copolymer can be controlled by the difference in styrene bond content and the difference in 1,2-vinyl bond content between the first and second copolymer units in the modified conjugated diene copolymer. As another example, the content of the second copolymer unit can be controlled by the ratio of the first and second copolymer units in the modified conjugated diene copolymer, or the difference in styrene bond content and the difference in 1,2-vinyl bond content between the first and second copolymer units. The content of the second copolymer unit, the styrene bond content and the 1,2-vinyl bond content of the first and second copolymer units depend on the monomer ratio, polymerization method and conditions, and can be affected by, for example, the initial polymerization conversion rate, the amount and time of addition of the polar additive, and the amount and time of addition of the monomer.

[0084] The modified conjugated diene copolymer may have a weight average molecular weight (Mw) measured by gel permeation chromatography (GPC) of 300,000 g / mol to 2,000,000 g / mol, 400,000 g / mol to 1,500,000 g / mol, or 500,000 g / mol to 1,200,000 g / mol. Within these ranges, rolling resistance and wet skid resistance can be more balanced and excellent.

[0085] In addition, the modified conjugated diene copolymer may have a unimodal molecular weight distribution curve measured by gel permeation chromatography (GPC), and the molecular weight distribution may be 1.0 or more and less than 1.7. Here, the unimodal curve shape and molecular weight distribution can both be satisfied by continuous polymerization, which will be described later.

[0086] Furthermore, the modified conjugated diene copolymer according to one embodiment of the present invention must have a Mooney viscosity measured under ASTM D1646 conditions of 40 to 120, preferably 45 to 100. There are various scales for evaluating processability, but when the Mooney viscosity satisfies the above range, excellent processability can be exhibited.

[0087] As yet another example, the modified conjugated diene-based polymer may have a shrinkage factor (g') of 0.7 or more, specifically 0.75 or more and 1.0 or less, more specifically 0.8 or more and 1.0 or less, as determined by gel permeation chromatography-light scattering method using a viscosity detector.

[0088] Here, the shrinkage factor (g') determined by the gel permeation chromatography-light scattering method is the ratio of the intrinsic viscosity of a branched polymer to that of a linear polymer having the same absolute molecular weight, and can be used as an index of the branched structure of a branched polymer, i.e., an index of the proportion of branches. For example, as the shrinkage factor decreases, the number of branches in the polymer tends to increase. Therefore, when comparing polymers with the same absolute molecular weight, the shrinkage factor decreases as the number of branches increases, and therefore, can be used as an index of the degree of branching.

[0089] The modified conjugated diene copolymer according to one embodiment of the present invention may contain the first polymer unit, the second copolymer unit, and a functional group derived from a modifier, and may have the styrene bond content, 1,2-vinyl bond content, weight average molecular weight, Mooney viscosity, and shrinkage factor adjusted within the respective ranges described above while satisfying conditions (i) to (vi). In this case, when applied to a rubber composition, the copolymer may achieve a more balanced and excellent wet skid resistance and rolling resistance without the risk of deterioration in abrasion resistance.

[0090] Method for producing modified conjugated diene copolymer The present invention provides a method for producing the modified conjugated diene copolymer.

[0091] The method for producing the modified conjugated diene copolymer includes step (S1) of polymerizing a conjugated diene monomer, or a conjugated diene monomer and an aromatic vinyl monomer, in a hydrocarbon solvent in the presence of a polymerization initiator and a polar additive to produce an activated polymer, and step (S2) of reacting the activated polymer produced in step (S1) with a modifier. The polymerization reaction (S1) and the modification reaction (S2) are carried out continuously, and step (S1) is carried out in two or more polymerization reactors. The polymerization conversion rate in the first polymerization reactor is 70% to 85%, and when the polymerization conversion rate after the start of polymerization is 70% or more but less than 95%, the aromatic vinyl monomer and the polar additive can be further added to carry out the polymerization reaction.

[0092] In the following, the characteristics of the produced modified conjugated diene copolymer and the modifier used in the reaction are the same as those described above, so the description thereof will be omitted.

[0093] The hydrocarbon solvent is not particularly limited, and may be, for example, one or more selected from the group consisting of n-pentane, n-hexane, n-heptane, isooctane, cyclohexane, toluene, benzene, and xylene.

[0094] According to one embodiment of the present invention, the polymerization initiator may be used in an amount of 0.01 mmol to 10 mmol, 0.05 mmol to 5 mmol, 0.1 mmol to 2 mmol, 0.1 mmol to 1 mmol, or 0.15 to 0.8 mmol based on 100 g of the total monomers.

[0033] The polymerization initiator may be, for example, one or more selected from the group consisting of methyl lithium, ethyl lithium, propyl lithium, isopropyl lithium, n-butyl lithium, s-butyl lithium, t-butyl lithium, hexyl lithium, n-decyl lithium, t-octyl lithium, phenyl lithium, 1-naphthyl lithium, n-eicosyl lithium, 4-butylphenyl lithium, 4-tolyl lithium, cyclohexyl lithium, 3,5-di-n-heptylcyclohexyl lithium, 4-cyclopentyl lithium, naphthyl sodium, naphthyl potassium, lithium alkoxide, sodium alkoxide, potassium alkoxide, lithium sulfonate, sodium sulfonate, potassium sulfonate, lithium amide, sodium amide, potassium amide, and lithium isopropyl amide.

[0095] The polymerization in step (S1) may be, for example, anionic polymerization, specifically, living anionic polymerization with anionic active sites at the polymerization termini due to an anionic propagation polymerization reaction. The polymerization in step (S1) may be temperature-rising polymerization, isothermal polymerization, or constant-temperature polymerization (adiabatic polymerization). The constant-temperature polymerization refers to a polymerization method that involves adding a polymerization initiator and then polymerizing using its own reaction heat without adding any heat. The temperature-rising polymerization refers to a polymerization method that adds heat after adding the polymerization initiator and then increases the temperature. The isothermal polymerization refers to a polymerization method that maintains a constant temperature of the polymer by adding heat or removing heat after adding the polymerization initiator.

[0096] According to one embodiment of the present invention, the polymerization in step (S1) may further include a diene compound having 1 to 10 carbon atoms in addition to the conjugated diene monomer, which has the effect of preventing gel formation on the reactor wall during long-term operation. The diene compound may be, for example, 1,2-butadiene.

[0097] According to one embodiment of the present invention, the polymerization in step (S1) is carried out in two or more polymerization reactors, and the polymerization conversion in the first polymerization reactor may be 70% to 85%, specifically 70% to 80%. That is, the polymerization in step (S1) may be carried out until the polymerization conversion in the first polymerization reactor reaches 70% or more, 70% to 85%, or 70% to 80%. When the polymerization conversion is within this range, side reactions occurring during polymer formation after the polymerization reaction is initiated can be suppressed, and a polymer with a linear structure can be obtained during polymerization. This allows the polymer to have the aforementioned unimodal molecular weight distribution curve and the molecular weight distribution to fall within the aforementioned range. The polymerization conversion can be controlled by adjusting the reaction temperature, reactor residence time, etc.

[0098] The polymerization in the first polymerization reactor may be carried out within a temperature range of, for example, 80° C. or less, −20° C. to 80° C., 0° C. to 80° C., 0° C. to 70° C., or 10° C. to 70° C. Within this range, the molecular weight distribution of the polymer can be narrowed, and excellent effects can be achieved in improving physical properties.

[0099] Furthermore, the polymerization in step (S1) can be carried out by further adding an aromatic vinyl monomer and a polar additive when the polymerization conversion rate is 70% or more but less than 95% after the initiation of polymerization. In this case, the ratio of the contents of the first polymer unit and the second copolymer unit in the modified conjugated diene copolymer produced and the microstructures (contents of styrene bonds and 1,2-vinyl bonds) in the first polymer unit and the second copolymer unit can be controlled, and the interaction parameter can be controlled as described above. As a result, the modified conjugated diene copolymer is advantageous in satisfying all of the conditions defined in (i) to (iv) above.

[0100] More specifically, the polymerization in step (S1) is carried out in two or more polymerization reactors. In the first polymerization reactor, a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer are polymerized in a hydrocarbon solvent in the presence of a polymerization initiator and a polar additive until a polymerization conversion of 70% or more or 70% to 85% is reached to produce an activated polymer having the above polymerization conversion. Polymerization continues in the second polymerization reactor and subsequent polymerization reactors. After the start of polymerization in the first polymerization reactor, additional aromatic vinyl monomer and polar additive can be added when the polymerization conversion is 70% or more but less than 95%. In this case, the additional aromatic vinyl monomer and polar additive can be added simultaneously or sequentially. They can be added at a single point within the above-mentioned polymerization conversion range, in portions at multiple points within the above-mentioned range, or continuously within the above-mentioned range.

[0101] In this case, the aromatic vinyl monomer and polar additive to be added may be used in appropriate amounts within a range that satisfies the above-mentioned difference in interaction parameters.

[0102] In yet another example, the additional aromatic vinyl monomer may be used in an amount of 5 g to 25 g, or 5 g to 20 g, based on 100 g of the monomers used in initiation, and the additional polar additive may be used in an amount of 0.001 g to 10 g, or 0.01 g to 1 g, more preferably 0.02 g to 0.5 g, based on 100 g of the monomers used in initiation. When the additional aromatic vinyl monomer and polar additive are controlled in the above amounts, the polymer microstructure can be more easily adjusted to satisfy the above-mentioned interaction parameter difference.

[0103] The total amount of polar additive used in the polymerization in step (S1) may be 0.001 g to 50 g, or 0.002 g to 1.0 g, based on 100 g of total monomers. As another example, the total amount of polar additive used may be greater than 0 g to 1 g, 0.01 g to 1 g, or 0.1 g to 0.9 g, based on 100 g of total polymerization initiators. Here, the total amount of polar additive used refers to the content including additional polar additives.

[0104] As another example, polymerization in a reactor to which an aromatic vinyl monomer and a polar additive are added when the polymerization conversion rate is 70% or more but less than 95% may be carried out at a temperature range of, for example, 80°C or less, -20°C to 80°C, 0°C to 80°C, 0°C to 70°C, or 10°C to 70°C. Within this range, the molecular weight distribution of the polymer can be narrowed, and excellent effects can be achieved in improving physical properties.

[0105] Meanwhile, to more easily satisfy the conditions (i) to (iii) of the present invention, the polymerization temperature in the first reactor and the subsequent reactor into which the aromatic vinyl monomer and polar additive are added may also have an effect. In this case, it is preferable to control the polymerization temperature in the reactor into which the aromatic vinyl monomer and polar additive are added to be equal to or lower than the polymerization temperature of the first reactor, and it is preferable that the polymerization temperature in the reactor into which the aromatic vinyl monomer and polar additive are added be 60°C or lower.

[0106] The polar additive may be, for example, one or more selected from the group consisting of tetrahydrofuran, ditetrahydrofurylpropane, diethyl ether, cyclopentyl ether, dipropyl ether, ethylene methyl ether, ethylene dimethyl ether, diethylene glycol, dimethyl ether, tert-butoxyethoxyethane, bis(3-dimethylaminoethyl)ether, (dimethylaminoethyl)ethyl ether, trimethylamine, triethylamine, tripropylamine, and tetramethylethylenediamine, and specifically may be triethylamine or tetramethylethylenediamine.

[0107] Meanwhile, the polymerization conversion rate can be determined, for example, by measuring the solid concentration in the copolymer solution containing the copolymer during polymerization. Specifically, to secure the copolymer solution, a cylindrical container is attached to the outlet of each polymerization reactor, a certain amount of the copolymer solution is filled into the cylindrical container, the cylindrical container is removed from the reactor, and the weight (A) of the cylinder filled with the copolymer solution is measured. The copolymer solution filled in the cylindrical container is then transferred to an aluminum container, for example, an aluminum dish, and the weight (B) of the cylindrical container from which the copolymer solution has been removed is measured. The aluminum container containing the copolymer solution is dried in an oven at 140°C for 30 minutes, and the weight (C) of the dried copolymer is measured, and the conversion rate can be calculated using the following mathematical formula 3:

[0108]

number

[0109] In Equation 3, the total solid content is the total solid content in the copolymer solution separated from each reactor, and is the weight percentage of solids relative to 100% copolymer solution. For example, if the total solid content is 20 wt%, it can be calculated by substituting 20 / 100, i.e., 0.2, when applying this to Equation 3.

[0110] Meanwhile, the polymer polymerized in the first reactor may be transferred in sequence to the polymerization reactor preceding the modification reactor, and polymerization may be continued until the final polymerization conversion rate reaches 95% or more. After polymerization in the first reactor, the polymerization conversion rate of each reactor from the second reactor to the polymerization reactor preceding the modification reactor may be appropriately adjusted for each reactor in order to adjust the molecular weight distribution.

[0111] In addition, the activated copolymer prepared in step (S1) may refer to a polymer in which a copolymer anion and an organometallic cation of a polymerization initiator are bonded.

[0112] In the present invention, the term "polymer" refers to an intermediate in the form of a polymer undergoing polymerization in each reactor during step (S1) before step (S1) or step (S2) is completed to obtain an activated polymer or modified conjugated diene-based copolymer, and may refer to a polymer undergoing polymerization in a reactor with a polymerization conversion rate of less than 95%.

[0113] According to one embodiment of the present invention, in the reaction of step (S2), the modifier may be used in an amount of 0.01 mmol to 10 mmol based on 100 g of the total monomers. As yet another example, the modifier may be used in a molar ratio of 1:0.1 to 10, 1:0.1 to 5, or 1:0.1 to 1:3 based on 1 mole of the polymerization initiator of step (S1).

[0114] According to one embodiment of the present invention, the modifying agent may be introduced into a modification reactor, and step (S2) may be performed in the modification reactor. Alternatively, the modifying agent may be introduced into a transfer section for transferring the activated polymer produced in step (S1) to a modification reactor for performing step (S2). The activated polymer and the modifying agent may be mixed in the transfer section to react with each other. The reaction may be a modification reaction in which the modifying agent is simply bonded to the activated polymer, or a coupling reaction in which the activated polymer is linked to the modifying agent.

[0115] Meanwhile, in the method for preparing the modified conjugated diene copolymer, a step of adding a conjugated diene monomer to the activated polymer prepared in step (S1) and reacting the added monomer with the activated polymer may be further carried out before the modification reaction in step (S2), which is more advantageous in the subsequent modification reaction. In this case, the conjugated diene monomer may be added in an amount of 1 mol to 100 mol per 1 mol of the activated polymer.

[0116] According to the present invention, there is provided a rubber composition containing the modified conjugated diene copolymer.

[0117] The rubber composition may contain the modified conjugated diene copolymer in an amount of 10% by weight or more, 10% to 100% by weight, or 20% to 90% by weight. When the amount is within this range, the rubber composition has excellent mechanical properties such as tensile strength and abrasion resistance, and an excellent balance between the various physical properties.

[0118] In addition, the rubber composition may further contain other rubber components, if necessary, in addition to the modified conjugated diene copolymer. In this case, the rubber components may be contained in an amount of 90% by weight or less based on the total weight of the rubber composition. As a specific example, the other rubber components may be contained in an amount of 1 part by weight to 900 parts by weight based on 100 parts by weight of the modified conjugated diene copolymer.

[0119] The rubber component may be, for example, natural rubber or synthetic rubber, and specific examples thereof include natural rubber (NR) containing cis-1,4-polyisoprene; modified natural rubbers obtained by modifying or refining the general natural rubbers, such as epoxidized natural rubber (ENR), deproteinized natural rubber (DPNR), and hydrogenated natural rubber; styrene-butadiene copolymer (SBR), polybutadiene (BR), polyisoprene (IR), butyl rubber (IIR), ethylene-propylene copolymer, polyisobutylene-co-isoprene, The rubber may be a synthetic rubber such as neoprene, poly(ethylene-co-propylene), poly(styrene-co-butadiene), poly(styrene-co-isoprene), poly(styrene-co-isoprene-co-butadiene), poly(isoprene-co-butadiene), poly(ethylene-co-propylene-co-diene), polysulfide rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, or halogenated butyl rubber, and any one or a mixture of two or more of these may be used.

[0120] The rubber composition may contain, for example, 0.1 to 200 parts by weight, or 10 to 120 parts by weight, of a filler relative to 100 parts by weight of the modified conjugated diene copolymer of the present invention. The filler may be, for example, a silica-based filler, and specific examples thereof include wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate, and colloidal silica. Wet silica is preferred, as it provides the best balance between improved fracture properties and wet grip. The rubber composition may further contain a carbon-based filler, if necessary.

[0121] As yet another example, when silica is used as the filler, a silane coupling agent may be used together to improve reinforcing properties and low heat buildup. Specific examples of the silane coupling agent include bis(3-triethoxysilylpropyl)tetrasulfide, bis(3-triethoxysilylpropyl)trisulfide, bis(3-triethoxysilylpropyl)disulfide, bis(2-triethoxysilylethyl)tetrasulfide, bis(3-trimethoxysilylpropyl)tetrasulfide, bis(2-trimethoxysilylethyl)tetrasulfide, 3-mercaptopropyltrimethoxysilane, 3-mercaptopropyltriethoxysilane, 2-mercaptoethyltrimethoxysilane, 2-mercaptoethyltriethoxysilane, 3-trimethoxysilylpropyl-N,N-dimethylthiocarbamoyltetrasulfide, 3-triethoxysilylpropyl-N,N-dimethylthiocarbamoyltetrasulfide, and the like. The polysilyl group may be, for example, 2-triethoxysilylethyl-N,N-dimethylthiocarbamoyl tetrasulfide, 3-trimethoxysilylpropyl benzothiazolyl tetrasulfide, 3-triethoxysilylpropyl benzolyl tetrasulfide, 3-triethoxysilylpropyl methacrylate monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis(3-diethoxymethylsilylpropyl)tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N,N-dimethylthiocarbamoyl tetrasulfide, or dimethoxymethylsilylpropyl benzothiazolyl tetrasulfide, and any one or a mixture of two or more of these may be used. In consideration of the effect of improving reinforcement, bis(3-triethoxysilylpropyl)polysulfide or 3-trimethoxysilylpropylbenzothiazyl tetrasulfide may be preferably used.

[0122] Furthermore, the rubber composition according to one embodiment of the present invention uses a modified conjugated diene copolymer as the rubber component, in which a functional group with high affinity for silica has been introduced into the active site, so the amount of silane coupling agent can be reduced compared to conventional cases. Therefore, the silane coupling agent may be used in an amount of 1 to 20 parts by weight, or 5 to 15 parts by weight, per 100 parts by weight of silica. Within this range, the silane coupling agent can be used to its full potential while preventing gelation of the rubber component.

[0123] The rubber composition according to one embodiment of the present invention may be sulfur crosslinkable and may further contain a vulcanizing agent. Specifically, the vulcanizing agent may be sulfur powder, and may be contained in an amount of 0.1 to 10 parts by weight per 100 parts by weight of the rubber component. When the amount is within this range, the vulcanized rubber composition can ensure the required elastic modulus and strength, and also has the effect of achieving excellent fuel economy.

[0124] In addition to the above components, the rubber composition according to an embodiment of the present invention may further include various additives commonly used in the rubber industry, specifically, a vulcanization accelerator, process oil, plasticizer, antioxidant, scorch inhibitor, zinc white, zinc oxide, stearic acid, a thermosetting resin, or a thermoplastic resin.

[0125] As the vulcanization accelerator, for example, thiazole compounds such as M (2-mercaptobenzothiazole), DM (dibenzothiazyl disulfide), and CZ (N-cyclohexyl-2-benzothiazyl sulfenamide), or guanidine compounds such as DPG (diphenyl guanidine) can be used, and they may be contained in an amount of 0.1 to 5 parts by weight per 100 parts by weight of the rubber component.

[0126] The process oil acts as a softener in the rubber composition and may be, for example, paraffinic, naphthenic, aromatic, or vegetable oil (e.g., soybean oil). Aromatic process oils are used in consideration of tensile strength and abrasion resistance, while naphthenic or paraffinic process oils are used in consideration of hysteresis loss and low-temperature properties. The process oil may be contained in an amount of, for example, 100 parts by weight or less per 100 parts by weight of the rubber component. Within this range, it is effective in preventing a decrease in the tensile strength and low heat buildup (fuel economy) of the vulcanized rubber.

[0127] Examples of the antioxidant include N-isopropyl-N'-phenyl-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, 6-ethoxy-2,2,4-trimethyl-1,2-dihydroquinoline, or a high-temperature condensate of diphenylamine and acetone, and may be used in an amount of 0.1 to 6 parts by weight per 100 parts by weight of the rubber component.

[0128] The rubber composition according to one embodiment of the present invention is obtained by kneading the rubber composition according to the compounding recipe using a kneading machine such as a Banbury mixer, a roll, or an internal mixer. After molding and processing, a vulcanization step is carried out to obtain a rubber composition having low heat buildup and excellent abrasion resistance.

[0129] As a result, the rubber composition is useful in the production of tire components such as tire treads, undertreads, sidewalls, carcass coating rubbers, belt coating rubbers, bead fillers, chafers, and bead coating rubbers, as well as various industrial rubber products such as dustproof rubbers, belt conveyors, and hoses.

[0130] The present invention also provides a tire manufactured using the rubber composition.

[0131] The tire may include a tire or a tire tread.

[0132] Example The present invention will be described in detail below with reference to examples. However, the examples of the present invention can be modified in various ways, and the scope of the present invention should not be construed as being limited to the examples described below. The examples of the present invention are provided to more completely explain the present invention to those skilled in the art.

[0133] Example 1 Of the three continuous stirred tank reactors (CSTRs), n-hexane was continuously fed into the first reactor at a flow rate of 8.6 kg / hr, a first monomer solution of 60 wt% styrene in n-hexane at 0.29 kg / hr and a first monomer solution of 60 wt% 1,3-butadiene in n-hexane at 2.7 kg / hr, an initiator solution of 2 wt% n-butyllithium in n-hexane at 40 g / hr, a first polar additive solution of 0.2 wt% ditetrahydrofurylpropane in n-hexane at 10 g / hr, and a first polar additive solution of 15 wt% 1,2-butadiene in n-hexane at 1 g / hr. The internal temperature of the reactor was maintained at 60°C, and when the polymerization conversion reached 75%, the polymer was transferred from the first reactor to the second reactor via a transfer pipe.

[0134] The temperature of the second reactor was maintained at 55°C, and a second monomer solution (60 wt% styrene dissolved in n-hexane) was continuously added at 200 g / hr, and a second polar additive solution (2 wt% ditetrahydrofurylpropane dissolved in n-hexane) was continuously added at 100 g / hr to carry out the reaction. When the polymerization conversion rate reached 95% or higher, a 1,3-butadiene solution (60 wt% 1,3-butadiene dissolved in n-hexane) was added at a rate of 50 g / hr to continue the reaction, and the polymer was then transferred from the second reactor to the third reactor via a transfer pipe.

[0135] The resulting polymer from the second reactor was then continuously fed to the third reactor, where a 5 wt% solution of 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-diethylpropan-1-amine) as a modifier was continuously added (n-butyllithium:modifier = 1:1 molar ratio). The polymerization solution discharged from the third reactor was then injected with a 30 wt% solution of IR1520 (BASF) as an antioxidant at a rate of 30 g / h and stirred. The resulting polymer was placed in steam-heated water, stirred to remove the solvent, and roll-dried to remove the remaining solvent and water, producing a modified conjugated diene copolymer.

[0136] Example 2 A modified conjugated diene copolymer was prepared in the same manner as in Example 1, except that the first monomer solution was a solution of 60 wt% 1,3-butadiene dissolved in n-hexane at 2.9 kg / hr, and the second monomer solution was a solution of 60 wt% styrene dissolved in n-hexane at 370 g / h.

[0137] Example 3 A modified conjugated diene copolymer was prepared in the same manner as in Example 2, except that the modification reaction was carried out by continuously supplying a solution of 5 wt% 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(1-(N-methylpiperazinyl)propane) dissolved in n-hexane instead of 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-diethylpropan-1-amine) as the modifier (n-butyllithium:modifier=1:1 molar ratio).

[0138] Comparative Example 1 Of the three continuous stirred tank reactors (CSTRs), n-hexane was continuously fed into the first reactor at a flow rate of 8.6 kg / hr, a first monomer solution of 60 wt% styrene in n-hexane at 0.6 kg / hr and a first monomer solution of 60 wt% 1,3-butadiene in n-hexane at 2.7 kg / hr, an initiator solution of 2 wt% n-butyllithium in n-hexane at 40 g / hr, a first polar additive solution of 2 wt% ditetrahydrofurylpropane in n-hexane at 200 g / hr, and a first polar additive solution of 15 wt% 1,2-butadiene in n-hexane at 1 g / hr. The internal temperature of the reactor was maintained at 60°C, and when the polymerization conversion reached 70%, the polymer was transferred from the first reactor to the second reactor via a transfer pipe.

[0139] Then, the temperature of the second reactor was maintained at 55°C, and when the polymerization conversion rate reached 95% or more, a 1,3-butadiene solution in which 1,3-butadiene was dissolved in n-hexane at a concentration of 60% by weight was injected at a rate of 50 g / h to continue the reaction, and then the polymer was transferred from the second reactor to the third reactor via a transfer pipe.

[0140] The polymer obtained in the second reactor was then continuously fed to a third reactor, and a modification reaction was carried out by continuously feeding a solution of 5 wt% 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(N,N-diethylpropan-1-amine) dissolved in n-hexane as a modifier (n-butyllithium:modifier = 1:1 molar ratio).

[0141] Then, a 30 wt% solution of IR1520 (BASF) as an antioxidant was added to the polymerization solution discharged from the second reactor at a rate of 30 g / h and stirred. The resulting polymer was placed in steam-heated hot water and stirred to remove the solvent, followed by roll drying to remove the remaining solvent and water, producing a modified conjugated diene copolymer.

[0142] Comparative Example 2 Of the three continuous stirred tank reactors (CSTRs), n-hexane was continuously fed into the first reactor at a flow rate of 8.6 kg / hr, a first monomer solution of 60 wt% styrene dissolved in n-hexane at 0.29 kg / hr and a first monomer solution of 60 wt% 1,3-butadiene dissolved in n-hexane at 2.8 kg / hr, an initiator solution of 2 wt% n-butyllithium dissolved in n-hexane at 40 g / hr, a first polar additive solution of 0.2 wt% ditetrahydrofurylpropane dissolved in n-hexane at 10 g / hr, and a first polar additive solution of 15 wt% 1,2-butadiene dissolved in n-hexane at 1 g / hr. The internal temperature of the reactor was maintained at 60°C, and when the polymerization conversion reached 71%, the polymer was transferred from the first reactor to the second reactor via a transfer pipe.

[0143] The temperature of the second reactor was maintained at 55°C, and a second monomer solution (60 wt% styrene dissolved in n-hexane) was continuously added at 70 g / hr, and a second polar additive solution (2 wt% ditetrahydrofurylpropane dissolved in n-hexane) was continuously added at 150 g / hr to carry out the polymerization reaction. When the polymerization conversion rate reached 95% or higher, a 1,3-butadiene solution (60 wt% 1,3-butadiene dissolved in n-hexane) was added at a rate of 50 g / hr to continue the reaction, and the polymer was then transferred from the second reactor to the third reactor via a transfer pipe.

[0144] The polymer obtained in the second reactor was then continuously fed to a third reactor, and a modification reaction was carried out by continuously feeding a solution of 5 wt% 3,3'-(1,1,3,3-tetramethoxydisiloxane-1,3-diyl)bis(1-(N-methylpiperazinyl)propane) dissolved in n-hexane as a modifier (n-butyllithium:modifier = 1:1 molar ratio).

[0145] Then, a 30 wt% solution of IR1520 (BASF) as an antioxidant was added to the polymerization solution discharged from the third reactor at a rate of 30 g / hr and stirred. The resulting polymer was placed in steam-heated hot water and stirred to remove the solvent, followed by roll drying to remove the remaining solvent and water, producing a modified conjugated diene copolymer.

[0146] Comparative Example 3 In Comparative Example 2, a modified conjugated diene copolymer was produced in the same manner as in Comparative Example 2, except that the second polar additive solution was injected at a rate of 250 g / hr.

[0147] Experimental Example Experimental Example 1 For each of the copolymers prepared in the examples and comparative examples, the difference in the content of styrene bonds and 1,2-vinyl bonds between the first copolymer unit and the second copolymer unit, as well as the glass transition temperature and weight average molecular weight (Mw, × 10 3 g / mol), molecular weight distribution (PDI, MWD), and molecular weight distribution curve were measured and are shown in Table 1 below.

[0148] 1) Glass transition temperature (Tg) In accordance with ISO22768:2006, a differential scanning calorimetry (DSCQ100, TA Corporation) was used to record a differential scanning calorimeter curve (DSC curve) while raising the temperature from -100°C at a rate of 10°C / min under a nitrogen flow of 50 ml / min. The peak top (inflection point) of the DSC differential curve was taken as the glass transition temperature, and the number of peaks was confirmed.

[0149] 2) Weight average molecular weight (Mw), molecular weight distribution (MWD), and molecular weight distribution curve The weight average molecular weight (Mw) and number average molecular weight (Mn) were measured using a GPC (gel permeation chromatograph) (PL GPC220, Agilent Technologies) under the following conditions, and a molecular weight distribution curve was obtained. The molecular weight distributions (PDI, MWD, Mw / Mn) were calculated from the measured molecular weights. -Column: Two PLgel Olexis (Polymer Laboratories) columns and one PLgel mixed-C (Polymer Laboratories) column were used in combination. -Solvent: Tetrahydrofuran mixed with 2% by weight of an amine compound -Flow rate: 1ml / min -Sample concentration: 1-2 mg / ml (diluted in THF) -Injection volume: 100μl -Column temperature: 40℃ -Detector: Refractive index -Standard: Polystyrene (corrected by a cubic function)

[0150] 3) Interaction parameter (X eff N) After analyzing the microstructure of each modified conjugated diene copolymer, the interaction parameter was calculated using the following mathematical formula 1.

[0151] [Mathematical formula 1] X eff N=[(x1-x2)(y2-y1)(X VS -X BS )+(y1-y 2 ) 2 X VB ]×N

[0152] In the above mathematical formula 1, N is the degree of polymerization of the modified conjugated diene copolymer, x1 is the volume ratio of styrene bonds in the first polymer, x2 is the volume ratio of styrene bonds in the second copolymer, y1 is the volume ratio of 1,2-vinyl bonds in butadiene in the first polymer, y2 is the volume ratio of 1,2-vinyl bonds in the butadiene in the second copolymer, X VS is 0.0565+5.62T -1 and X BS is 0.00843+10.2T -1 and X VB is 0.00269+1.87T -1 where T is room temperature and the unit is absolute temperature (K).

[0153] The volume ratios of 1,2-vinyl bonds and styrene bonds in each copolymer were measured and analyzed using a Varian VNMR 500 MHz NMR. Specifically, 1,1,2,2-tetrachloroethane was used as the solvent during measurement. The solvent peak was calculated to be 5.97 ppm. The volume ratios of styrene bonds and 1,2-vinyl bonds were calculated using the peaks of random styrene from 7.2 to 6.9 ppm, block styrene from 6.9 to 6.2 ppm, 1,4-vinyl bonds from 5.8 to 5.1 ppm, and 1,2-vinyl bonds from 5.1 to 4.5 ppm. Samples were prepared by dissolving 10 mg of polymer in 1 mL of 1,1,2,2-tetrachloroethane.

[0154] The degree of polymerization of each copolymer was calculated from the number of bonded molecules in the number average molecular weight (Mn) measured by the GPC analysis, based on the ratio of repeating units derived from styrene and 1,3-butadiene in the copolymer.

[0155] 4) Content of second copolymer unit The content of the second copolymer unit in the copolymers of Examples 1 to 3 and Comparative Examples 2 to 4 was calculated by the following mathematical formula 4.

[0156] On the other hand, the second copolymer unit represents a polymer chain unit formed after the additional monomer is added.

[0157] [Mathematical formula 4] Second copolymer unit content (wt%) = [(M1YC1)-(M o γC o ) / (M1ΥC1)]×100

[0158] In Equation 4, M1 is the total weight of the monomers contained in the first and second monomer solutions, C1 is the final polymerization conversion before adding the modifier, M0 is the weight of the monomers contained in the first monomer solution, and C0 is the polymerization conversion just before adding the second monomer solution, where each monomer solution represents the monomer solution used in preparing the copolymers of the Examples and Comparative Examples.

[0159] 5) Contraction Factor The shrinkage factor was determined using a GPC-light scattering analyzer (GPCmax VE-2001, Malvern) in which a light scattering detector, an RI detector, and a viscometer (TDA305, Malvern) connected in sequence to three columns packed with polystyrene gel were connected. The absolute molecular weight was obtained from the light scattering detector and the RI detector, and the intrinsic viscosity [η] corresponding to the absolute molecular weight was obtained from the RI detector and the viscometer. The intrinsic viscosity [η]0 of the linear polymer corresponding to the absolute molecular weight was then calculated using the following mathematical formula 2. The average value of the ratio of the intrinsic viscosities ([η] / [η]0) corresponding to each absolute molecular weight was expressed as the shrinkage factor. In this case, a mixed solution of tetrahydrofuran and triethylamine (THF in TEA: prepared by mixing 5 mmol of triethylamine with 1 L of tetrahydrofuran) was used as the eluent, and a combination of TSKgel G4000HXL (Tosoh Corporation), TSKgel G5000HXL (Tosoh Corporation), and TSKgel G6000HXL (Tosoh Corporation) was used as the column. The sample was prepared by dissolving 20 mg of polymer in 10 mL of THF, and 100 μL of the measurement solution was injected into the GPC measurement device and measured under conditions of an oven temperature of 40°C and a THF flow rate of 1.0 mL / min.

[0160] [Mathematical formula 2] [η]0=10 -3.883 M 0.771

[0161] In the above mathematical formula 2, M is the absolute molecular weight.

[0162] [Table 1]

[0163] In Table 1, two glass transition temperature peaks, Tg1 and Tg2, were detected in Examples 1 to 3 and Comparative Examples 2 and 3, but one glass transition temperature peak was detected in Comparative Example 1. Tg1 represents the glass transition temperature of the first polymer unit, and Tg2 represents the glass transition temperature of the second copolymer unit. As shown in Table 1, the modified conjugated diene-based copolymers of Examples 1 to 3 satisfied all of the conditions (i) to (vi) presented in this specification.

[0164] In contrast to this, the modified conjugated diene polymers of Comparative Examples 1 to 3 either did not satisfy the interaction parameter requirements or did not simultaneously satisfy both the interaction parameter requirements and the number of peaks in the differential curve.

[0165] Experimental Example 2 In order to compare and analyze the physical properties of the rubber compositions containing each modified conjugated diene copolymer prepared in the examples and comparative examples and the molded articles prepared therefrom, the tensile properties, viscoelastic properties, and processability properties were measured, and the results are shown in Table 3 below.

[0166] 1) Preparation of rubber test specimens Each modified conjugated diene copolymer of the examples and comparative examples was used as raw rubber and compounded under the compounding conditions shown in Table 2. The raw materials in Table 2 are in parts by weight based on 100 parts by weight of the raw rubber.

[0167] [Table 2]

[0168] Specifically, the rubber test pieces are kneaded through a first-stage kneading and a second-stage kneading. In the first stage kneading, raw rubber, silica (filler), an organic silane coupling agent (X50S, Evonik), process oil (TDAE oil), zinc oxide (ZnO), stearic acid, an antioxidant (TMQ(RD) (2,2,4-trimethyl-1,2-dihydroquinoline polymer), an antioxidant (6PPD (dimethylbutyl)-N-phenyl-phenylenediamine), and a wax (microcrystalline cellulose)) are mixed using a Banbury mixer equipped with a temperature control device. Wax) was mixed into the mixer. The initial temperature of the mixer was controlled at 70°C, and after mixing was completed, the primary compound was obtained at a discharge temperature of 145°C. In the second mixing stage, the primary compound was cooled to room temperature, and then the primary compound, sulfur, rubber accelerator (DPG (diphenyl guanidine)), and vulcanization accelerator (CZ (N-cyclohexyl-2-benzothiazyl sulfenamide)) were added to the mixer and mixed at a temperature of 100°C to obtain a secondary compound. This was followed by a curing process at 160°C for 20 minutes, after which rubber test specimens were prepared.

[0169] 2) Tensile properties The tensile properties were measured by preparing test specimens according to the tensile testing method of ASTM 412, measuring the tensile strength at break and the tensile stress at 300% elongation (300% modulus) of the test specimens. Specifically, the tensile properties were measured at room temperature at a speed of 50 cm / min using a Universal Test Machine 4204 (Instron).

[0170] 3) Viscoelastic properties The viscoelastic properties were measured using a dynamic mechanical analyzer (GABO) in film tension mode at a frequency of 10 Hz and at various measurement temperatures (-95°C to 70°C) to determine the tan δ value. A higher tan δ value at a low temperature of 0°C indicates better wet skid resistance, while a lower tan δ value at a high temperature of 60°C indicates less hysteresis loss and better rolling resistance (fuel economy). The results in Table 3 below are indexed based on the measurement results of Comparative Example 1, and therefore the higher the value, the better the performance.

[0171] Also, the E' (dynamic modulus of elasticity) value at room temperature (25°C) was checked, and the higher the value, the better the steering performance.

[0172] [Table 3]

[0173] In Table 3, the tensile properties, tan δ at 0°C, and E' at 25°C of Examples 1 to 3 and Comparative Examples 2 and 3 were calculated using the measured value of Comparative Example 1 as the reference value according to the following mathematical formula 5, and the tan δ at 60°C of Examples 1 to 3 and Comparative Examples 2 and 3 was calculated using the measured value of Comparative Example 1 as the reference value according to the following mathematical formula 6.

[0174] [Mathematical formula 5] Index (%) = (measured value / reference value) x 100

[0175] [Mathematical formula 6] Index (%) = (reference value / measured value) x 100

[0176] As shown in Table 3, Examples 1 to 3 according to one embodiment of the present invention were excellent in balance in all of tensile properties, wet skid resistance, and rolling resistance compared to Comparative Examples 1 to 3.

[0177] In this case, Examples 1 to 3 satisfy all of the conditions (i) to (vi) presented in the present invention, while Comparative Examples 1 to 3 do not satisfy one or more of the above conditions.

[0178] The above results indicate that the modified conjugated diene-based copolymer of the present invention, which contains first polymer units, second copolymer units, and functional groups derived from a modifier, and satisfies the specific conditions defined in (i) to (vi), has the effect of improving tensile properties, wet skid resistance, and rolling resistance in a balanced manner.

Claims

1. comprising first polymer units, second copolymer units, and functional groups derived from a modifier; the first polymer unit contains a repeating unit derived from a conjugated diene monomer, and the second copolymer unit contains a repeating unit derived from a conjugated diene monomer and a repeating unit derived from an aromatic vinyl monomer, A modified conjugated diene copolymer that satisfies the following conditions (i) to (vi): (i) the differential scanning calorimetry curve measured in accordance with ISO 22768:2006 using a differential scanning calorimetry (DSC) while raising the temperature from −100° C. to 100° C. at a rate of 10° C. / min under a nitrogen flow of 50 ml / min shows two peaks; (ii) the glass transition temperature of the first polymer unit is lower than the glass transition temperature of the second copolymer unit; (iii) the glass transition temperature of the first polymer unit is −100° C. to −40° C.; (iv) the glass transition temperature of the second copolymer unit is greater than -40°C by 10°C; (v) the content of the second copolymer unit is 5% by weight to 40% by weight; (vi) The interaction parameter (X) defined by the following mathematical formula 1 at room temperature ｅｆｆ N) is 15 or more; [Mathematical formula 1] X ｅｆｆ N=[(x １ -x ２ )(y ２ -y １ )(X ＶＳ -X ＢＳ )+(y １ -y ２ ) ２ X ＶＢ ]×N In the above mathematical formula 1, N is the degree of polymerization of the modified conjugated diene copolymer, x １ is the volume ratio of styrene bonds in the first polymer, x ２ is the volume ratio of styrene bonds in the second copolymer, y １ is the volume ratio of 1,2-vinyl bonds in butadiene in the first polymer, y ２ is the volume ratio of 1,2-vinyl bonds in the butadiene in the second copolymer, X ＶＳ is 0.0565 + 5.62T －１ and X ＢＳ is 0.00843 + 10.2T －１ and X ＶＢ is 0.00269 + 1.87T －１ where T is room temperature and the unit is absolute temperature (K).

2. The interaction parameter (X ｅｆｆ 2. The modified conjugated diene copolymer according to claim 1, wherein N) is 18 or more.

3. The modified conjugated diene copolymer according to claim 1 , wherein the first polymer unit further comprises a repeating unit derived from an aromatic vinyl monomer.

4. The modified conjugated diene copolymer according to claim 1, wherein the glass transition temperature of the second copolymer unit is 40°C to 120°C higher than the glass transition temperature of the first polymer unit.

5. 2. The modified conjugated diene copolymer according to claim 1, which has a single-peak molecular weight distribution curve determined by gel permeation chromatography and a molecular weight distribution of 1.0 or more and less than 1.

7.

6. 2. The modified conjugated diene copolymer according to claim 1, which has a shrinkage factor (g') of 0.7 or more as determined by gel permeation chromatography-light scattering method equipped with a viscosity detector.

7. The modified conjugated diene copolymer according to claim 1 , wherein the functional group derived from the modifier is bonded to one end of the second copolymer unit.

8. The modified conjugated diene copolymer according to claim 1, wherein the Si and N contents are each 50 ppm or more based on the total weight of the copolymer.

9. The modified conjugated diene copolymer according to claim 1 , wherein the modifier is an alkoxysilane compound.

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