KR102744314B1 - Modified conjugated diene polymer and rubber composition comprising the same - Google Patents

Abstract

The present invention relates to a modified conjugated diene polymer and a rubber composition comprising the same. The modified conjugated diene polymer thus obtained has a narrow molecular weight distribution curve having a unimodal shape in a gel permeation chromatography manner, and contains a functional group derived from a modified monomer and a functional group derived from a modifier represented by the chemical formula 1, thereby exhibiting excellent processability as well as excellent tensile properties and viscoelastic properties.

Description

Modified conjugated diene polymer and rubber composition comprising the same {MODIFIED CONJUGATED DIENE POLYMER AND RUBBER COMPOSITION COMPRISING THE SAME}

The present invention relates to a modified conjugated diene polymer having excellent processability as well as excellent tensile strength and viscoelastic properties, and a rubber composition comprising the same.

Recently, in response to the demand for fuel efficiency in automobiles, conjugated diene polymers that have low rolling resistance, excellent wear resistance and tensile properties, and also have steering stability represented by wet road resistance are required as rubber materials for tires.

In order to reduce the rolling resistance of tires, there is a method of reducing the hysteresis loss of vulcanized rubber, and as evaluation indices of such vulcanized rubber, rebound elasticity, tan δ, Goodrich heat generation, etc. at 50℃ to 80℃ are used. In other words, a rubber material having a large rebound elasticity or a small tan δ and Goodrich heat generation at the above temperature is desirable.

Natural rubber, polyisoprene rubber, or polybutadiene rubber are known as rubber materials with small hysteresis loss, but they have the problem of low wet road resistance. Therefore, conjugated diene polymers or copolymers such as styrene-butadiene rubber (hereinafter referred to as SBR) or butadiene rubber (hereinafter referred to as BR) have been manufactured by emulsion polymerization or solution polymerization and used as rubber for tires. Among these, the greatest advantage of solution polymerization over emulsion polymerization is that the vinyl structure content and styrene content, which determine the rubber properties, can be arbitrarily controlled, and the molecular weight and properties can be controlled by coupling or modification. Therefore, the structure of the finally manufactured SBR or BR is easy to change, and the movement of the chain ends can be reduced by bonding or modification of the chain ends, and the bonding strength with fillers such as silica or carbon black can be increased, so SBR manufactured by solution polymerization is widely used as a rubber material for tires.

When such solution-polymerized SBR is used as a rubber material for tires, the glass transition temperature of the rubber can be raised by increasing the vinyl content in the SBR, thereby controlling the tire's required physical properties such as driving resistance and braking power, and fuel consumption can be reduced by appropriately controlling the glass transition temperature. The solution-polymerized SBR is manufactured using an anionic polymerization initiator, and the chain terminals of the formed polymer are bonded or modified using various modifiers and used. For example, U.S. Patent No. 4,397,994 proposes a technology for bonding the active anion of the chain terminal of a polymer obtained by polymerizing styrene-butadiene in a nonpolar solvent using a monofunctional initiator, alkyllithium, using a bonding agent such as a tin compound.

Meanwhile, the polymerization of the SBR or BR can be carried out by batch or continuous polymerization. In the case of batch polymerization, the molecular weight distribution of the manufactured polymer is narrow, so there is an advantage in terms of improving physical properties, but there are problems such as low productivity and poor processability. In the case of continuous polymerization, the polymerization is carried out continuously, so there is an advantage in terms of excellent productivity and improving processability, but there is a problem such as poor physical properties due to a broad molecular weight distribution. Accordingly, there is a continuous demand for research to simultaneously improve productivity, processability, and physical properties when manufacturing SBR or BR.

US 4397994 A

The present invention has been made to solve the problems of the above-mentioned prior art, and aims to provide a modified conjugated diene polymer which is manufactured by continuous polymerization and has excellent processability, excellent physical properties such as tensile properties, and excellent viscoelastic properties, and a rubber composition comprising the same.

According to one embodiment of the present invention for solving the above problems, the present invention provides a modified conjugated diene polymer having a molecular weight distribution curve by gel permeation chromatography (GPC) having a unimodal shape, a molecular weight distribution (PDI; MWD) of 1.0 or more and less than 1.7, a functional group derived from a modified monomer represented by the following chemical formula 1, and a functional group derived from a piperazine-based modifier at at least one terminal:

[Chemical Formula 1]

In the above chemical formula 1,

F ₁ is an amine-containing functional group, and R ₁ is an alkenyl group having 2 to 10 carbon atoms.

In addition, the present invention provides a rubber composition comprising the modified conjugated diene polymer and a filler.

The modified conjugated diene polymer according to the present invention has a narrow molecular weight distribution of less than 1.7 and a unimodal molecular weight distribution curve as determined by gel permeation chromatography, and may have excellent processability as well as superior tensile and viscoelastic properties.

In addition, the modified conjugated diene polymer according to the present invention can further improve tensile properties and viscoelastic properties by including a functional group derived from a modified monomer and a functional group derived from a modifier at least at one terminal.

The following drawings attached to this specification illustrate specific embodiments of the present invention, and together with the contents of the invention described above, serve to further understand the technical idea of the present invention, and therefore, the present invention should not be interpreted as being limited to matters described in such drawings.
FIG. 1 shows a molecular weight distribution curve of a modified conjugated diene polymer of Example 1 according to one embodiment of the present invention, as determined by gel permeation chromatography (GPC).
Figure 2 shows a molecular weight distribution curve of a modified conjugated diene polymer of Comparative Example 1 according to one embodiment of the present invention, as determined by gel permeation chromatography (GPC).
Figure 3 shows a molecular weight distribution curve of a modified conjugated diene polymer of Comparative Example 2 according to one embodiment of the present invention, as determined by gel permeation chromatography (GPC).
Figure 4 shows a molecular weight distribution curve of a modified conjugated diene polymer of Comparative Example 3 according to one embodiment of the present invention, obtained by gel permeation chromatography (GPC).

Hereinafter, the present invention will be described in more detail to help understand the present invention.

The terms or words used in the description and claims of the present invention should not be interpreted as limited to their usual or dictionary meanings, but should be interpreted as meanings and concepts that conform to the technical idea of the present invention, based on the principle that the inventor can appropriately define the concept of the term in order to explain his or her own invention in the best manner.

In the present invention, the term 'substitution' may mean that a hydrogen of a functional group, an atomic group, or a compound is substituted with a specific substituent, and when a hydrogen of a functional group, an atomic group, or a compound is substituted with a specific substituent, one or two or more substituents may be present depending on the number of hydrogens present in the functional group, an atomic group, or a compound, and when multiple substituents are present, each of the substituents may be the same as or different from each other.

In the present invention, the term 'alkyl group' may mean a monovalent aliphatic saturated hydrocarbon, and may mean all of linear alkyl groups such as methyl, ethyl, propyl, and butyl; branched alkyl groups such as isopropyl, sec-butyl, tert-butyl, and neopentyl; and cyclic saturated hydrocarbons, or cyclic unsaturated hydrocarbons including one or more unsaturated bonds.

In the present invention, the term 'alkylene group' may mean a divalent aliphatic saturated hydrocarbon such as methylene, ethylene, propylene, and butylene.

In the present invention, the term 'cycloalkyl group' may mean a cyclic saturated hydrocarbon.

In the present invention, the term 'aryl group' may mean a cyclic aromatic hydrocarbon, and may also mean a monocyclic aromatic hydrocarbon in which one ring is formed, or a polycyclic aromatic hydrocarbon in which two or more rings are combined.

The term 'heterocyclic group' in the present invention refers to a cyclic saturated hydrocarbon, or a cyclic unsaturated hydrocarbon containing one or more unsaturated bonds, wherein carbon atoms in the hydrocarbon may be substituted with one or more heteroatoms, and wherein the heteroatoms may be selected from N, O, and S.

In the present invention, the term 'monovalent hydrocarbon group' refers to a monovalent substituent derived from a hydrocarbon group, and may refer to a monovalent atomic group in which carbon and hydrogen are bonded, such as an alkyl group, an alkenyl group, an alkynyl group, a cycloalkyl group, a cycloalkyl group including one or more unsaturated bonds, and an aryl group, and the monovalent atomic group may have a linear or branched structure depending on the structure of the bond.

In the present invention, the term 'divalent hydrocarbon group' refers to a divalent substituent derived from a hydrocarbon group, and may refer to a divalent atomic group in which carbon and hydrogen are bonded, such as an alkylene group, an alkenylene group, an alkynylene group, a cycloalkylene group, a cycloalkylene group including one or more unsaturated bonds, and an arylene group, and the divalent atomic group may have a linear or branched structure depending on the structure of the bond.

In the present invention, the term 'single bond' may mean a single covalent bond itself that does not include a separate atom or molecular group.

In the present invention, the terms 'derived unit' and 'derived functional group' may mean a component, structure, or the substance itself derived from a certain substance.

The present invention provides a modified conjugated diene polymer having excellent processability as well as excellent tensile and viscoelastic properties.

According to one embodiment of the present invention, a modified conjugated diene polymer has a unimodal molecular weight distribution curve as determined by gel permeation chromatography (GPC), a molecular weight distribution (PDI; MWD) of 1.0 or more and less than 1.7, and includes a functional group derived from a modified monomer represented by the following chemical formula 1, and includes a functional group derived from a piperazine-based modifier at at least one terminal.

[Chemical Formula 1]

In the above chemical formula 1,

F ₁ is an amine-containing functional group, and R ₁ is an alkenyl group having 2 to 10 carbon atoms.

According to one embodiment of the present invention, the modified conjugated diene polymer may include a repeating unit derived from a conjugated diene monomer, a functional group derived from a modified monomer, and a functional group derived from a modifier. The repeating unit derived from the conjugated diene monomer may refer to a repeating unit formed when the conjugated diene monomer is polymerized, and the functional group derived from the modified monomer and the functional group derived from the modifier may refer to a functional group derived from a modified monomer and a functional group derived from a modifier, respectively, present in a polymer chain.

In addition, the functional group derived from the modified monomer may be present within the polymer chain or may be present at at least one terminal of the polymer chain, and when the functional group derived from the modified monomer is present at one terminal of the polymer chain, the functional group derived from the modified monomer may be present at one terminal of the polymer chain and the functional group derived from the modifier may be present at the other terminal. That is, in this case, the modified conjugated diene polymer according to one embodiment of the present invention may be a double-terminal modified conjugated diene polymer in which both terminals are modified.

In addition, according to another embodiment of the present invention, the modified conjugated diene polymer may be a copolymer including a repeating unit derived from a conjugated diene monomer, a repeating unit derived from an aromatic vinyl monomer, a functional group derived from a modified monomer, and a functional group derived from a modifier. Here, the repeating unit derived from an aromatic vinyl monomer may mean a repeating unit formed when an aromatic vinyl monomer is polymerized.

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).

The above aromatic vinyl monomer may be at least one selected from the group consisting of, for example, styrene, α-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 1-vinylnaphthalene, 4-cyclohexylstyrene, 4-(p-methylphenyl)styrene, 1-vinyl-5-hexylnaphthalene, 3-(2-pyrrolidino ethyl)styrene, 4-(2-pyrrolidino ethyl)styrene, and 3-(2-pyrrolidino-1-methyl ethyl)-α-methylstyrene.

As another example, the modified conjugated diene polymer may be a copolymer further including a repeating unit derived from a diene monomer having 1 to 10 carbon atoms together with the repeating unit derived from the conjugated diene monomer. The repeating unit derived from the diene monomer may be a repeating unit 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 modified conjugated diene polymer is a copolymer further including a diene monomer, the modified conjugated diene polymer may include a repeating unit derived from the diene monomer in an amount of from more than 0 wt% to 1 wt%, from more than 0 wt% to 0.1 wt%, from more than 0 wt% to 0.01 wt%, or from more than 0 wt% to 0.001 wt%, and has an effect of preventing gel formation within this range.

According to one embodiment of the present invention, the copolymer may be a random copolymer, in which case there is an excellent effect of balance between each property. The random copolymer may mean that the repeating units forming the copolymer are arranged randomly.

According to one embodiment of the present invention, the modified conjugated diene polymer may have a number average molecular weight (Mn) of 1,000 g/mol to 2,000,000 g/mol, 10,000 g/mol to 1,000,000 g/mol, or 100,000 g/mol to 800,000 g/mol, a weight average molecular weight (Mw) of 1,000 g/mol to 3,000,000 g/mol, 10,000 g/mol to 2,000,000 g/mol, or 100,000 g/mol to 2,000,000 g/mol, and a peak average molecular weight (Mp) of 1,000 g/mol to 3,000,000 g/mol, 10,000 g/mol to 2,000,000 g/mol. g/mol, or 100,000 g/mol to 2,000,000 g/mol. Within this range, there is an excellent effect in cloud resistance and wet road resistance. As another example, the modified conjugated diene polymer may have a molecular weight distribution (PDI; MWD; Mw/Mn) of 1.0 or more to less than 1.7, or 1.1 or more to less than 1.7, and within this range, there is an effect in which the tensile properties and viscoelastic properties are excellent, and the balance between each physical property is excellent. At the same time, the modified conjugated diene polymer has a molecular weight distribution curve by gel permeation chromatography (GPC) that has a unimodal shape, which is a molecular weight distribution appearing in a polymer polymerized by continuous polymerization, and may mean that the modified conjugated diene polymer has uniform characteristics. That is, a modified conjugated diene polymer according to one embodiment of the present invention may be manufactured by continuous polymerization and have a molecular weight distribution curve of a unimodal shape, while having a molecular weight distribution of 1.0 or more and less than 1.7.

In general, when a conjugated diene polymer is manufactured by a batch polymerization method and a modification reaction is performed, the molecular weight distribution curve of the manufactured modified conjugated diene polymer has a multi-modal molecular weight distribution curve that is bimodal or more. Specifically, in the case of batch polymerization, the polymerization reaction is initiated after all raw materials are input, and since chain growth can occur simultaneously from the initiation points generated by a plurality of initiators, the growth of each chain can be generally uniform, and accordingly, the molecular weights of the manufactured polymer chains are constant, and the molecular weight distribution can be a unimodal form that is considerably narrow. However, when a modification agent is input to perform a modification reaction, two cases can occur: 'when modification does not occur' and 'when modification and coupling occur', and accordingly, two groups having a large difference in molecular weight can be formed between the polymer chains, which ultimately forms a multi-modal molecular weight distribution curve with two or more peaks. Meanwhile, in the case of a continuous polymerization method according to an embodiment of the present invention, unlike batch polymerization, the initiation of the reaction and the input of raw materials are performed continuously, the point in time at which the reaction is initiated is different, and accordingly, the initiation of polymerization varies, such as from the beginning of the reaction, in the middle of the reaction, or at the end of the reaction, so that when the polymerization reaction is completed, polymer chains having various molecular weights are manufactured. Accordingly, a specific peak does not appear dominantly in the curve representing the distribution of molecular weight, so that the molecular weight distribution curve appears broadly as a single peak, and even if a chain whose polymerization is initiated at the end of the reaction is coupled, the molecular weight of the chain whose polymerization is initiated at the beginning of the reaction can be similar to that of the chain whose polymerization is initiated at the end of the reaction, so that the diversity of the molecular weight distribution can be maintained the same, so that a unimodal distribution curve is still generally maintained.

However, even when manufacturing and modifying a polymer by a batch polymerization method, the modification conditions can be adjusted to have a unimodal form, but in this case, the entire polymer must be uncoupled or the entire polymer must be coupled, and in other cases, a unimodal molecular weight distribution curve cannot be exhibited.

In addition, even though the modified conjugated diene polymer is manufactured by a batch polymerization method as described above, if the molecular weight distribution curve of the modified conjugated diene polymer shows a unimodal distribution, when the entire polymer is coupled, only polymers having the same level of molecular weight exist, which may result in poor processability, and since the functional groups capable of interacting with fillers such as silica or carbon black decrease due to coupling, the compounding properties may be poor, and in the opposite case, when the entire polymer is not coupled, the functional groups at the terminals of the polymer, which should interact with fillers such as silica or carbon black during processing, may have a dominant interaction between the functional groups at the terminals of the polymer than with the filler, which may interfere with the interaction with the filler, and thus the processability may be significantly poor. Therefore, when the polymer is manufactured by a batch polymerization method and controlled to have a unimodal molecular weight distribution curve, there may be a problem that the processability and compounding properties of the manufactured modified conjugated diene polymer are poor, and in particular, the processability may be significantly poor.

Meanwhile, whether or not a modified conjugated diene polymer is coupled can be confirmed by the coupling number (C.N), where the coupling number is a numerical value that depends on the number of functional groups to which the polymer can be bonded in the modifier after modification of the polymer. In other words, it represents the ratio of a polymer in which there is no coupling between polymer chains and only terminal modification is achieved and a polymer in which a plurality of polymer chains are coupled to one modifier, and can have a range of 1≤C.N≤F, where F represents the number of functional groups in the modifier that can react with the terminals of the active polymer. In other words, a modified conjugated diene polymer having a coupling number of 1 means that none of the polymer chains are coupled, and a modified conjugated diene polymer having a coupling number of F means that all of the polymer chains are coupled.

Therefore, the modified conjugated diene polymer according to one embodiment of the present invention may have a molecular weight distribution curve of a unimodal form, while having a coupling number greater than 1 and less than the number of functional groups of the modifier used (1<C.N<F).

As another example, the modified conjugated diene polymer may have a Si content of 50 ppm or more, 100 ppm or more, 100 ppm to 10,000 ppm, or 100 ppm to 5,000 ppm based on weight, and within this range, the rubber composition including the modified conjugated diene polymer has excellent mechanical properties such as tensile properties and viscoelastic properties. The Si content may refer to the content of Si atoms present in the modified conjugated diene polymer. Meanwhile, the Si atoms may be derived from a functional group derived from a modifier.

As another example, the modified conjugated diene polymer may have an N content of 50 ppm or more, 100 ppm or more, 100 ppm to 10,000 ppm, or 100 ppm to 5,000 ppm based on the total weight, and within this range, the rubber composition including the modified conjugated diene polymer has excellent mechanical properties such as tensile properties and viscoelastic properties. The N content may refer to the content of N atoms present in the modified conjugated diene polymer, and in this case, the N atoms may be derived from a functional group derived from a modifier.

The above Si content may be measured, for example, by an ICP analysis method, and the ICP analysis method may be measured using an inductively coupled plasma optical emission spectrometer (ICP-OES; Optima 7300DV). When the inductively coupled plasma optical emission spectrometer is used, about 0.7 g of the sample is placed in a platinum crucible, about 1 mL of concentrated sulfuric acid (98 wt%, Electronic grade) is added, and the sample is heated at 300°C for 3 hours, and the sample is annealed in an electric furnace (Thermo Scientific, Lindberg Blue M) using the following program of steps 1 to 3,

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(holdtime) 370 ℃ (2hr)

3) step 3: initial temp 370℃, rate (temp/hr) 47 ℃/hr, temp(holdtime) 510 ℃ (3hr)

It can be measured by adding 1 mL of concentrated nitric acid (48 wt%) and 20 ㎕ of concentrated hydrofluoric acid (50 wt%) to the residue, sealing the platinum crucible, and shaking for more than 30 minutes, then adding 1 mL of boric acid to the sample, storing it at 0°C for more than 2 hours, diluting it in 30 mL of ultrapure water, and performing incineration.

At this time, the sample is placed in hot water heated by steam and stirred to remove the solvent, thereby obtaining a modified conjugated diene polymer from which residual monomers, residual denaturants, and oils are removed.

In addition, the N content may be measured, for example, through an NSX analysis method, and the NSX analysis method may be measured using a trace nitrogen quantitative analyzer (NSX-2100H).

For example, in case of using the above trace nitrogen quantitative analyzer, the trace nitrogen quantitative analyzer (Auto sampler, Horizontal furnace, PMT & Nitrogen detector) was turned on and the carrier gas flow rates were set to 250 ml/min for Ar, 350 ml/min for _O2 , and 300 ml/min for ozonizer, and the heater was set to 800℃, and then the analyzer was stabilized for about 3 hours. After the analyzer was stabilized, a calibration curve was created with a Nitrogen standard (AccuStandard S-22750-01-5 ml) for a calibration curve range of 5 ppm, 10 ppm, 50 ppm, 100 ppm, and 500 ppm, and the Area corresponding to each concentration was obtained, and a straight line was created using the ratio of the Area to the concentration. Thereafter, a ceramic boat containing 20 mg of the sample was placed on the Auto sampler of the analyzer and measured to obtain the area. The N content was calculated using the area of the obtained sample and the above calibration curve.

At this time, the sample used in the above NSX analysis method may be a modified conjugated diene polymer sample that has been stirred in hot water heated with steam to remove the solvent, and may be a sample from which residual monomer and residual denaturant have been removed. In addition, if oil is added to the above sample, it may be a sample after the oil has been extracted (removed).

As another example, the modified conjugated diene polymer may have a Mooney relaxation rate measured at 100°C of 0.7 or more, 0.7 or more and 3.0 or less, 0.7 or more and 2.5 or less, or 0.7 or more and 2.0 or less.

Here, the Mooney relaxation rate indicates the change in stress that appears in response to the same amount of strain, and may be measured using a Mooney viscometer. Specifically, the Mooney relaxation rate was obtained by using a Large Rotor of Monsanto MV2000E, leaving the polymer at room temperature (23±5℃) for more than 30 minutes under the conditions of 100℃ and a rotor speed of 2±0.02 rpm, then sampling 27±3 g and filling it into the die cavity, operating the platen to apply torque, measuring Mooney viscosity, and then measuring the slope value of the Mooney viscosity change that appears when the torque is released.

Meanwhile, the Mooney relaxation ratio can be used as an indicator of the branching structure of the polymer. For example, when comparing polymers with the same Mooney viscosity, the more branches there are, the smaller the Mooney relaxation ratio becomes, so it can be used as an indicator of the degree of branching.

In addition, the modified conjugated diene polymer may have a Mooney viscosity of 30 or more, 40 to 150, or 40 to 140 at 100°C, and has excellent processability and productivity within this range.

As another example, the modified conjugated diene polymer may have a shrinkage factor (g') of 0.8 or more, specifically 0.8 or more and 3.0 or less, and more specifically 0.8 or more and 1.3 or less, as determined by gel permeation chromatography-light scattering measurement with a viscosity detector.

Here, the shrinkage factor (g') obtained by the gel permeation chromatography-photodispersion method measurement is a ratio of the intrinsic viscosity of a branched polymer to the intrinsic viscosity of a linear polymer having the same absolute molecular weight, and can be used as an indicator of the branch structure of the branched polymer, that is, an indicator of the proportion occupied by the branch, and for example, as the shrinkage factor decreases, the number of branches of the polymer tends to increase, and therefore, when comparing polymers having the same absolute molecular weight, the shrinkage factor decreases as the number of branches increases, and therefore, it can be used as an indicator of the degree of branching.

In addition, the shrinkage factor was calculated based on the solution viscosity and light scattering method by measuring the chromatogram using a gel chromatography-light scattering measuring device equipped with a viscosity detector, and specifically, a GPC-light scattering measuring device equipped with a light scattering detector and a viscosity detector connected to two columns using polystyrene gel as a filler was used to obtain the absolute molecular weight and the intrinsic viscosity corresponding to each absolute molecular weight, and then the intrinsic viscosity of the linear polymer corresponding to the absolute molecular weight was calculated, and the shrinkage factor was obtained as the ratio of the intrinsic viscosity corresponding to each absolute molecular weight. For example, the shrinkage factor was obtained by injecting a sample into a GPC-light scattering measuring device (Viscotek TDAmax, Malvern Co.) equipped with a light scattering detector and a viscosity detector, obtaining the absolute molecular weight from the light scattering detector, and obtaining the intrinsic viscosity [η] for the absolute molecular weight from the light scattering detector and the viscosity detector, and then calculating the intrinsic viscosity [η] ₀ of the linear polymer for the absolute molecular weight using the following mathematical equation 2, and expressing the average value of the ratio of the intrinsic viscosities corresponding to each absolute molecular weight ([η]/[η] ₀ ) as the shrinkage factor. At this time, the eluent used was a mixed solution of tetrahydrofuran and N,N,N',N'-tetramethylethylenediamine (adjusted by mixing 20 mL of N,N,N',N'-tetramethylethylenediamine in 1 L of tetrahydrofuran), the column used PL Olexix (Agilent Corporation), and the measurement was performed under the conditions of an oven temperature of 40°C and a THF flow rate of 1.0 mL/min, and the sample was prepared by dissolving 15 mg of the polymer in 10 mL of THF.

[Mathematical formula 2]

[η] ₀ =10 ^-3.883 M ^0.771

In the above mathematical expression 2, M is the absolute molecular weight.

In addition, the modified conjugated diene polymer may have a vinyl content of 5 wt% or more, 10 wt% or more, or from 10 wt% to 60 wt%. Here, the vinyl content may mean the content of a 1,2-added, but not a 1,4-added, conjugated diene monomer with respect to 100 wt% of the conjugated diene copolymer composed of a monomer having a vinyl group and an aromatic vinyl monomer.

Meanwhile, the modified monomer represented by the chemical formula 1 according to one embodiment of the present invention may be capable of introducing a functional group into the polymer chain while forming a polymer chain by polymerizing with another monomer.

Specifically, in the chemical formula 1, F ₁ may be a 5-membered heterocyclic group having 2 to 4 carbon atoms and including at least one heteroatom selected from the group consisting of N, O, and S.

More specifically, the modified monomer represented by the chemical formula 1 may be a compound represented by the following chemical formula 2.

[Chemical formula 2]

In the above chemical formula 2, R ₂ is an alkenyl group having 2 to 10 carbon atoms.

More specifically, the modified monomer represented by the chemical formula 1 may be a compound represented by the following chemical formula 3, namely 1-vinylimidazole (1-vinyl-1H-imidazole).

[Chemical Formula 3]

In addition, the modifier according to the present invention may be a modifier for modifying at least one terminal of a conjugated diene polymer, and a specific example thereof may be a silica affinity modifier. The silica affinity modifier may refer to a modifier containing a silica affinity functional group in a compound used as a modifier, and the silica affinity functional group may refer to a functional group having excellent affinity with a filler, particularly a silica-based filler, such that interaction between the silica-based filler and the functional group derived from the modifier is possible.

Specifically, according to one embodiment of the present invention, the piperazine-based modifier may be selected from compounds represented by the following chemical formulae 4 to 6.

[Chemical Formula 4]

In the above chemical formula 4,

R _a1 and R _a2 are each independently an alkylene group having 1 to 20 carbon atoms or -R _a7 [OR _a8 ] _n3 -, wherein R _a7 and R _a8 are each independently an alkylene group having 1 to 20 carbon atoms, n ₃ is an integer from 1 to 30,

R _a3 to R _a6 are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms,

n ₁ and n ₂ are integers independently selected from 0 to 3, and n ₁ +n ₂ is an integer greater than or equal to 1,

[Chemical Formula 5]

In the above chemical formula 5,

R _b1 is an alkyl group having 1 to 10 carbon atoms, -R _b19 SiR _b9 R _b10 R _b11 or -R _b12 A, wherein R _b9 to R _b11 are each independently an alkyl group having 1 to 10 carbon atoms, R _b12 is an alkylene group having 1 to 10 carbon atoms, R _b19 is a single bond or an alkylene group having 1 to 10 carbon atoms, and A is a substituent represented by the following chemical formula 5a,

R _b2 to R _b4 are independently an alkylene group having 1 to 10 carbon atoms,

R _b5 to R _b8 are independently an alkyl group having 1 to 10 carbon atoms,

m ₁ and m ₂ are independently integers from 1 to 3,

[Chemical formula 5a]

In the above chemical formula 5a, R _b13 and R _b14 are each independently an alkylene group having 1 to 10 carbon atoms, R _b15 to R _b18 are each independently an alkyl group having 1 to 10 carbon atoms, m ₃ and m ₄ are each independently an integer of 1 to 3,

[Chemical formula 6]

In the above chemical formula 6,

A ₁ and A ₂ are independently an alkylene group having 1 to 6 carbon atoms, which is unsubstituted or substituted with an alkyl group having 1 to 4 carbon atoms,

R _c1 to R _c4 are independently a halogen group or an alkoxy group having 1 to 6 carbon atoms,

R _c5 to R _c8 are independently an alkyl group having 1 to 3 carbon atoms,

o ₁ is an integer from 1 to 5, and o ₂ and o ₃ are, independently of each other, integers from 0 to 4.

Specifically, in the chemical formula 4, R _a1 and R _a2 are each independently an alkylene group having 1 to 10 carbon atoms or -R _a7 [OR _a8 ] _n3 -, wherein R _a7 and R _a8 are each independently an alkylene group having 1 to 10 carbon atoms, n ₃ is an integer from 1 to 30, R _a3 to R _a6 can each independently be an alkyl group having 1 to 10 carbon atoms, n ₁ and n ₂ are each independently an integer selected from 0 to 3, and n ₁ + n ₂ can be an integer greater than or equal to 1.

More specifically, the compound represented by the chemical formula 4 is 1,4-bis(3-(3-(triethoxysilyl)propoxy)propyl)piperazine, 1,4-bis(3-(triethoxysilyl)propyl)piperazine, 1,4-bis(3-(triethoxysilyl)propyl)piperazine, 1,4-bis(3-(trimethoxysilyl)propyl)piperazine, 1,4-bis(3-(dimethoxymethylsilyl)propyl)piperazine, It may be at least one selected from the group consisting of 1-(3-(ethoxydimethylsilyl)propyl)-4-(3-(triethoxysilyl)propyl)piperazine, 1-(3-(ethoxydimethyl)propyl)-4-(3-(triethoxysilyl)methyl)piperazine, and 1-(3-(ethoxydimethyl)methyl)-4-(3-(triethoxysilyl)propyl)piperazine.

In addition, in the chemical formula 5, R _b1 is an alkyl group having 1 to 6 carbon atoms, -R ₁₉ SiR _b9 R _b10 R _b11 or -R _b12 A, wherein R _b9 to R _b11 are each independently an alkyl group having 1 to 6 carbon atoms, R _b12 is an alkylene group having 1 to 6 carbon atoms, R _b19 is a single bond or an alkylene group having 1 to 6 carbon atoms, A is a substituent represented by chemical formula 5a, R _b2 to R _b4 are each independently an alkylene group having 1 to 6 carbon atoms, R _b5 to R _b8 are each independently an alkyl group having 1 to 6 carbon atoms, m ₁ and m ₂ are each independently an integer of 1 to 3, and in chemical formula 5a, R _b13 and R _b14 are each independently an alkylene group having 1 to 6 carbon atoms, and R _b15 to R _b18 is independently an alkyl group having 1 to 6 carbon atoms, and m ₃ and m ₄ can be independently an integer of 1 to 3.

More specifically, the compound represented by the chemical formula 5 may be at least one selected from compounds represented by the following chemical formulas 5-1 to 5-3.

[Chemical Formula 5-1]

[Chemical Formula 5-2]

[Chemical Formula 5-3]

In the chemical formulas 5-1 to 5-3 above, R _b2 to R _b8 , R _b12 to R _b19 and m ₁ to m ₄ are as defined in the chemical formula 5 above.

In addition, in the chemical formula 6, A ₁ and A ₂ are each independently an alkylene group having 1 to 6 carbon atoms which is unsubstituted or substituted with an alkyl group having 1 to 4 carbon atoms, R _c1 to R _c4 are each independently a halogen group or an alkoxy group having 1 to 4 carbon atoms, R _c5 to R _c8 are each independently an alkyl group having 1 to 3 carbon atoms, o ₁ is an integer of 1 or 2, and o ₂ and o ₃ are each independently an integer of 0 to 4.

More specifically, the compound represented by the chemical formula 6 may be a compound represented by the following chemical formula 6-1.

[Chemical Formula 6-1]

As described above, the modified conjugated diene polymer according to one embodiment of the present invention may have a specific structure, and a unique molecular weight distribution and shape. The structure of the polymer may be expressed by properties such as a shrinkage factor, a Mooney relaxation rate, and a coupling number, and the molecular weight distribution and its shape may be expressed by a molecular weight distribution value, a shape of a molecular weight distribution curve, and a coupling number, and both-end modification by a modifier and a modified monomer may affect the structure and the molecular weight distribution and its shape. The parameters expressing the structure of the polymer and the features related to the molecular weight distribution can be satisfied by the manufacturing method described below.

In addition, it is preferable to manufacture through this manufacturing method to satisfy the above-mentioned characteristics, but if all of the above-mentioned characteristics are satisfied, the effect intended for implementation in the present invention can be achieved.

In addition, the present invention provides a method for producing the modified conjugated diene polymer. The modified conjugated diene polymer according to one embodiment of the present invention can have a unimodal molecular weight distribution curve by gel permeation chromatography and a narrow molecular weight distribution of 1.0 or more and less than 1.7 by producing the modified conjugated diene polymer by the production method described below. Accordingly, the modified conjugated diene polymer can have excellent processability and excellent tensile properties and viscoelastic properties in a balanced manner.

According to one embodiment of the present invention, a method for producing a modified conjugated diene polymer comprises a step (S1) of polymerizing a modified monomer represented by the following chemical formula 1 and a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer in the presence of a polymerization initiator in a hydrocarbon solvent to produce an active polymer having a functional group derived from the modified monomer introduced; and a step (S2) of reacting or coupling the active polymer produced in step (S1) with a piperazine-based modifier, wherein step (S1) is performed continuously in two or more polymerization reactors, and a polymerization conversion rate in a first reactor among the polymerization reactors may be 50% or less.

[Chemical Formula 1]

In the above chemical formula 1, F ₁ and R ₁ are as defined above, and the piperazine-based modifier is as described above.

The hydrocarbon solvent is not particularly limited, but may be at least one selected from the group consisting of n-pentane, n-hexane, n-heptane, isooctane, cyclohexane, toluene, benzene, and xylene.

The polymerization initiator is not particularly limited, but may be at least one selected from the group consisting of methyllithium, ethyllithium, propyllithium, isopropyllithium, n-butyllithium, s-butyllithium, t-butyllithium, hexyllithium, n-decyllithium, t-octyllithium, phenyllithium, 1-naphthyllithium, n-eicosyllithium, 4-butylphenyllithium, 4-tolyllithium, cyclohexyllithium, 3,5-di-n-heptylcyclohexyllithium, 4-cyclopentyllithium, naphthylsodium, naphthylpotassium, lithium alkoxide, sodium alkoxide, potassium alkoxide, lithium sulfonate, sodium sulfonate, potassium sulfonate, lithium amide, sodium amide, potassium amide, and lithium isopropylamide.

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 monomer. Here, the total 100 g of the monomer may represent the total amount of the modified monomer and the conjugated diene monomer, or the total amount of the modified monomer, the conjugated diene monomer, and the aromatic vinyl monomer.

In addition, according to one embodiment of the present invention, the modified monomer can be used in an amount of 0.001 g to 10 g, preferably 0.01 g to 10 g, and more preferably 0.1 g to 10 g, per 100 g of the conjugated diene monomer.

The polymerization of the step (S1) may be, for example, anionic polymerization, and as a specific example, may be a living anionic polymerization having an anion active site at the polymerization terminal by a growth polymerization reaction by anion. In addition, the polymerization of the step (S1) may be temperature-elevated polymerization, isothermal polymerization, or isothermal polymerization (adiabatic polymerization), and the isothermal polymerization may mean a polymerization method including a step of polymerizing by the heat of reaction itself without arbitrarily applying heat after introducing a polymerization initiator, the temperature-elevated polymerization may mean a polymerization method of increasing the temperature by arbitrarily applying heat after introducing the polymerization initiator, and the isothermal polymerization may mean a polymerization method of maintaining the temperature of the polymerization product constant by applying heat to increase the heat or removing heat after introducing the polymerization initiator.

In addition, according to one embodiment of the present invention, the polymerization in step (S1) may be carried out by further including a diene compound having 1 to 10 carbon atoms in addition to the conjugated diene monomer, and in this case, there is an effect of preventing a gel from being formed on the wall of the reactor during long-term operation. An example of the diene compound may be 1,2-butadiene.

The polymerization in the above step (S1) can 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, and within this range, the molecular weight distribution of the polymer is narrowly controlled, thereby having an excellent effect of improving physical properties.

The active polymer manufactured by the above step (S1) may mean a polymer in which a polymer anion and an organic metal cation are combined.

According to one embodiment of the present invention, the method for producing the modified conjugated diene polymer can be carried out by a continuous polymerization method in a plurality of reactors including two or more polymerization reactors and a modification reactor. As a specific example, the step (S1) can be carried out continuously in two or more polymerization reactors including the first reactor, and the number of the polymerization reactors can be flexibly determined according to the reaction conditions and environment. The continuous polymerization method can mean a reaction process of continuously supplying a reactant to a reactor and continuously discharging the generated reaction product. In the case of the continuous polymerization method, there is an effect of excellent productivity and processability, and excellent uniformity of the polymer produced.

In addition, according to one embodiment of the present invention, when continuously producing an active polymer in the polymerization reactor, the polymerization conversion rate in the first reactor can be 50% or less, 10% to 50%, or 20% to 50%, and within this range, after the polymerization reactor is initiated, side reactions occurring while the polymer is formed can be suppressed, thereby inducing a polymer having a linear structure during polymerization, and accordingly, it is possible to narrowly control the molecular weight distribution of the polymer, so that there is an excellent effect of improving physical properties.

At this time, the polymerization conversion rate can be controlled according to the reaction temperature, reactor residence time, etc.

The above polymerization conversion rate can be determined, for example, by measuring the solid concentration of a polymer solution phase containing a polymer during polymerization of the polymer, and as a specific example, in order to secure the polymer solution, a cylindrical container is mounted at the outlet of each polymerization reactor, a certain amount of the polymer solution is filled into the cylindrical container, the cylindrical container is separated from the reactor, the weight (A) of the cylinder filled with the polymer solution is measured, the polymer solution filled in the cylindrical container is transferred to an aluminum container, for example, an aluminum dish, the weight (B) of the cylindrical container from which the polymer solution has been removed is measured, the aluminum container containing the polymer solution is dried in an oven at 140°C for 30 minutes, the weight (C) of the dried polymer is measured, and the result may be calculated according to the following mathematical formula 1.

[Mathematical formula 1]

Meanwhile, the polymer polymerized in the first reactor can be sequentially transferred to a polymerization reactor before the denaturation reactor so that polymerization can proceed until the final polymerization conversion rate becomes 95% or higher, and after polymerization in the first reactor, the polymerization conversion rate of each reactor from the second reactor or the second reactor to the polymerization reactor before the denaturation reactor can be appropriately controlled for each reactor to control the molecular weight distribution.

Meanwhile, in the step (S1), when producing the active polymer, the residence time of the polymer in the first reactor can be 1 minute to 40 minutes, 1 minute to 30 minutes, or 5 minutes to 30 minutes, and within this range, the polymerization conversion rate can be easily controlled, and thus, the molecular weight distribution of the polymer can be narrowly controlled, and accordingly, there is an excellent effect of improving the physical properties.

In the present invention, the term 'polymer' may mean an intermediate in the form of a polymer that is polymerized within each reactor during the execution of step (S1) prior to obtaining an active polymer or a modified conjugated diene polymer by completing step (S1) or step (S2), and may mean a polymer having a polymerization conversion rate of less than 95% that is polymerized within the reactor.

According to one embodiment of the present invention, the molecular weight distribution (PDI, polydispersed index; MWD, molecular weight distribution; Mw/Mn) of the active polymer manufactured in the step (S1) may be less than 1.5, 1.0 or more to less than 1.5, or 1.1 or more to less than 1.5, and within this range, the molecular weight distribution of the modified conjugated diene polymer manufactured through a modification reaction or coupling with a modifier is narrow, so that there is an excellent effect of improving physical properties.

Meanwhile, the polymerization of the step (S1) may be carried out including a polar additive, and the polar additive may be added in a proportion of 0.001 g to 50 g, 0.001 g to 10 g, or 0.005 g to 0.1 g based on 100 g of the total monomer. In another example, the polar additive may be added in a proportion of 0.001 g to 10 g, 0.005 g to 5 g, or 0.005 g to 4 g based on 1 mmol of the total polymerization initiator.

The polar additive may be, for example, at least one selected from the group consisting of tetrahydrofuran, 2,2-di(2-tetrahydrofuryl)propane, diethyl ether, cycloamyl ether, dipropyl ether, ethylene methyl ether, ethylene dimethyl ether, diethyl glycol, dimethyl ether, tert-butoxyethoxyethane, bis(3-dimethylaminoethyl) ether, (dimethylaminoethyl) ethyl ether, trimethylamine, triethylamine, tripropylamine, N,N,N',N'-tetramethylethylenediamine, sodium mentholate, and 2-ethyl tetrahydrofurfuryl ether, and preferably 2,2-di(2-tetrahydrofuryl)propane, triethylamine, tetramethylethylenediamine, sodium mentholate, or 2-ethyl tetrahydrofurfuryl. It may be ether (2-ethyl tetrahydrofurfuryl ether), and when the polar additive is included, it has the effect of inducing easy formation of a random copolymer by compensating for the difference in reaction speed between a conjugated diene monomer and an aromatic vinyl monomer when copolymerizing them.

According to one embodiment of the present invention, the reaction or coupling of step (S2) can be performed in a modification reactor, and at this time, the modification agent can be used in an amount of 0.01 mmol to 10 mmol based on 100 g of the total monomer. In another example, the modification agent can 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 mol of the polymerization initiator of step (S1).

In addition, according to one embodiment of the present invention, the denaturant may be introduced into a denaturation reactor, and the step (S2) may be performed in the denaturation reactor. As another example, the denaturant may be introduced into a transport section for transporting the active polymer produced in the step (S1) to a denaturation reactor for performing the step (S2), and a reaction or coupling may proceed by mixing the active polymer and the denaturant within the transport section.

The method for producing the modified conjugated diene polymer according to one embodiment of the present invention is a method capable of satisfying the characteristics of the modified conjugated diene polymer described above, and the effect to be achieved in the present invention as described above can be achieved when the above characteristics are satisfied, but at least in the manufacturing method, the polymerization conversion rate when transferring from the first reactor to the second reactor in a continuous process must be satisfied, and other polymerization conditions are controlled in various ways, thereby realizing the physical properties of the modified conjugated diene polymer according to the present invention.

In addition, the present invention provides a rubber composition comprising the above-mentioned modified conjugated diene polymer.

The above rubber composition may contain the modified conjugated diene polymer in an amount of 10 wt% or more, 10 wt% to 100 wt%, or 20 wt% to 90 wt%, and within this range, the composition has excellent mechanical properties such as tensile strength and wear resistance, and excellent balance between each property.

In addition, the rubber composition may further include other rubber components as needed in addition to the modified conjugated diene polymer, and at this time, the rubber component may be included in an amount of 90 wt% or less based on the total weight of the rubber composition. As a specific example, the other rubber component may be included in an amount of 1 to 900 wt% based on 100 wt% of the modified conjugated diene polymer.

The above rubber component may be, for example, natural rubber or synthetic rubber, and specific examples thereof include natural rubber (NR) including cis-1,4-polyisoprene; modified natural rubber such as epoxidized natural rubber (ENR), deproteinized natural rubber (DPNR), and hydrogenated natural rubber, which are modified or refined from the above general natural rubber; It can be a synthetic rubber such as styrene-butadiene copolymer (SBR), polybutadiene (BR), polyisoprene (IR), butyl rubber (IIR), ethylene-propylene copolymer, polyisobutylene-co-isoprene, 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, halogenated butyl rubber, and any one of these or a mixture of two or more thereof can be used.

The above rubber composition may contain, for example, 0.1 to 200 parts by weight, or 10 to 120 parts by weight, of a filler based on 100 parts by weight of the modified conjugated diene polymer of the present invention. The filler may be, for example, a silica-based filler, and specific examples thereof may include wet silica (hydrated silicic acid), dry silica (anhydrous silicic acid), calcium silicate, aluminum silicate, or colloidal silica, and preferably wet silica, which has the most excellent effect of improving fracture characteristics and achieving wet grip properties. In addition, the rubber composition may further contain a carbon black-based filler, if necessary.

As another example, when silica is used as the filler, a silane coupling agent may be used together to improve reinforcing properties and low heat generation, and 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, 2-Triethoxysilylethyl-N,N-dimethylthiocarbamoyltetrasulfide, 3-Trimethoxysilylpropylbenzothiazolyltetrasulfide, 3-Triethoxysilylpropylbenzolyltetrasulfide, 3-Triethoxysilylpropylmethacrylate monosulfide, 3-Trimethoxysilylpropylmethacrylate monosulfide, bis(3-diethoxymethylsilylpropyl)tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl-N,N-dimethylthiocarbamoyltetrasulfide, or dimethoxymethylsilylpropylbenzothiazolyltetrasulfide, and the like, and any one or a mixture of two or more of these may be used. Preferably, considering the effect of improving reinforcing properties, it may be bis(3-triethoxysilylpropyl)polysulfide or 3-trimethoxysilylpropylbenzothiazyl tetrasulfide.

In addition, since the rubber composition according to one embodiment of the present invention uses a modified conjugated diene polymer having a functional group having high affinity for silica introduced into an active site as a rubber component, the amount of the silane coupling agent can be reduced compared to the usual case, and accordingly, the silane coupling agent can be used in an amount of 1 to 20 parts by weight, or 5 to 15 parts by weight, based on 100 parts by weight of silica, and within this range, the effect as a coupling agent is sufficiently exhibited while also having the effect of preventing gelation of the rubber component.

The rubber composition according to one embodiment of the present invention may be sulfur crosslinkable and may further include a vulcanizing agent. The vulcanizing agent may be specifically sulfur powder and may be included in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the rubber component, and within this range, the vulcanized rubber composition has the effect of securing the necessary elastic modulus and strength while exhibiting excellent fuel efficiency.

The rubber composition according to one embodiment of the present invention may further include, in addition to the above-described components, various additives commonly used in the rubber industry, specifically, a vulcanization accelerator, a process oil, an antioxidant, a plasticizer, an anti-aging agent, a scorch inhibitor, zinc white, stearic acid, a thermosetting resin, or a thermoplastic resin.

The above-mentioned vulcanization accelerator may be, for example, a thiazole-based compound such as M(2-mercaptobenzothiazole), DM(dibenzothiazyl disulfide), CZ(N-cyclohexyl-2-benzothiazyl sulfenamide), or a guanidine-based compound such as DPG (diphenyl guanidine), and may be included in an amount of 0.1 to 5 parts by weight per 100 parts by weight of the rubber component.

The above process oil acts as a softener in the rubber composition, and may be, for example, a paraffinic, naphthenic, or aromatic compound. When considering tensile strength and wear resistance, an aromatic process oil may be used, and when considering hysteresis loss and low-temperature characteristics, a naphthenic or paraffinic process oil may be used. The above process oil may be included in an amount of, for example, 100 parts by weight or less with respect to 100 parts by weight of the rubber component, and within this range, there is an effect of preventing a decrease in the tensile strength and low heat generation (low fuel consumption) of the vulcanized rubber.

The antioxidant may be, for example, 2,6-di-t-butylparacresol, dibutylhydroxytoluenyl, 2,6-bis((dodecylthio)methyl)-4-nonylphenol or 2-methyl-4,6-bis((octylthio)methyl)phenol, and may be used in an amount of 0.1 to 6 parts by weight per 100 parts by weight of the rubber component.

The above-mentioned anti-aging agent may be, for example, 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.

The rubber composition according to one embodiment of the present invention can be obtained by mixing using a mixer such as a Banbury mixer, a roll mixer, or an internal mixer according to the above compounding prescription, and a rubber composition having low heat generation and excellent wear resistance can be obtained by a vulcanization process after molding processing.

Accordingly, the rubber composition can be useful in the manufacture of various components of a tire, such as a tire tread, undertread, sidewall, carcass coating rubber, belt coating rubber, bead filler, squeegee, or bead coating rubber, or various industrial rubber products, such as an anti-vibration rubber, belt conveyor, and hose.

In addition, the present invention provides a tire manufactured using the rubber composition.

The above tire may include a tire or tire tread.

Hereinafter, the present invention will be described in detail by way of examples in order to specifically explain the present invention. However, the examples according to the present invention may be modified in various different forms, 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 in order to more completely explain the present invention to a person having average knowledge in the art.

Example 1

In the first reactor of the continuous reactor having three reactors connected in series, a styrene solution containing 60 wt% of styrene dissolved in n-hexane was fed at 1.85 kg/h, a 1,3-butadiene solution containing 60 wt% of 1,3-butadiene dissolved in n-hexane was fed at 11.9 kg/h, a modified monomer solution containing 15 wt% of 1-vinyl imidazole dissolved in n-hexane was fed at 30 g/h, a n-hexane 48.0 kg/h, a 1,2-butadiene solution containing 2.0 wt% of 1,2-butadiene dissolved in n-hexane was fed at 40 g/h, a solution containing 10 wt% of 2,2-(di-2(tetrahydrofuryl)propane as a polar additive was fed at 61.0 g/h, and a solution containing n-butyllithium dissolved in n-hexane was fed at A 6.6 wt% n-butyllithium solution was injected at a rate of 106.1 g/h. At this time, the temperature of the first reactor was maintained at 50°C, and when the polymerization conversion rate reached 40%, the polymer was transferred from the first reactor to the second reactor through a transfer pipe.

Next, a 1,3-butadiene solution containing 60 wt% of 1,3-butadiene dissolved in n-hexane was injected into the second reactor at a rate of 2.96 kg/h. At this time, the temperature of the second reactor was maintained at 65°C, and when the polymerization conversion rate was 95% or higher, the polymer was transferred from the second reactor to the third reactor through a transfer pipe.

The polymer was transferred from the second reactor to the third reactor, and a solution containing 20 wt% of 1,4-bis(3-(triethoxysilyl)propyl)piperazine as a denaturant was introduced into the third reactor at a rate of 64.0 g/h. The temperature of the third reactor was maintained at 65°C.

After this, a solution of IR1520 (BASF) dissolved at 30 wt% as an antioxidant was injected at a rate of 167 g/h into the polymerization solution discharged from the third reactor and stirred. The resulting polymer was placed in hot water heated by steam and stirred to remove the solvent, thereby producing a modified conjugated diene polymer.

Example 2

In Example 1, when the polymerization conversion reached 38%, the polymer was transferred from the first reactor to the second reactor through the transfer pipe, and a solution containing 20 wt% of 1-(3-(ethoxydimethylsilyl)propyl-4-(3-(triethoxysilyl)propyl)piperazine instead of 1,4-bis(3-(triethoxysilyl)propyl)piperazine as a modifier was continuously supplied to the third reactor at a rate of 116.0 g/h, except that the same procedure as in Example 1 was carried out to produce a modified conjugated diene polymer.

Example 3

In Example 1, when the polymerization conversion reached 41%, the polymer was transferred from the first reactor to the second reactor through the transfer pipe, and a solution containing 20 wt% of 1-(3-(ethoxydimethylsilyl)propyl-4-(3-(triethoxysilyl)methyl)piperazine instead of 1,4-bis(3-(triethoxysilyl)propyl)piperazine as a modifier was continuously supplied to the third reactor at a rate of 103.5 g/h, except that the same procedure as in Example 1 was carried out to produce a modified conjugated diene polymer.

Example 4

In Example 1, instead of 1,4-bis(3-(triethoxysilyl)propyl)piperazine as a modifier, a solution containing 20 wt% of 1,1,1-trimethoxy-N-((triethoxysilyl)methyl)-N-((4-((trimethylsilyl)methyl)piperazine-1-yl)methyl)silanamine was continuously supplied to the third reactor at a rate of 103.5 g/h, except that the same procedure as in Example 1 was carried out to produce a modified conjugated diene polymer.

Example 5

In Example 1, a solution containing 20 wt% of 1,1,3,3-tetramethoxy-1,3-bis(2-(4-methylpiperazine-1-yl)ethyl)disiloxane instead of 1,4-bis(3-(triethoxysilyl)propyl)piperazine as a modifier was continuously supplied to the third reactor at a rate of 103.5 g/h, except that the same procedure as in Example 1 was carried out to produce a modified conjugated diene polymer.

Comparative Example 1

A 20 L autoclave reactor was charged with 110 g of styrene, 870 g of 1,3-butadiene, 0.54 g of 1-vinyl imidazole, 5,000 g of n-hexane, and 1.13 g of 2,2-di(2-tetrahydrofuryl)propane as a polar additive, and the internal temperature of the reactor was increased to 50°C. When the internal temperature of the reactor reached 50°C, 5.5 mmol of n-butyllithium was added to perform an adiabatic temperature-raising reaction. After 20 minutes, 20 g of 1,3-butadiene was added to cap the polymer chain ends with butadiene. After 5 minutes, 5.5 mmol of 3-(dimethoxy(methyl)silyl)-N,N-diethylpropan-1-amine was added as a denaturant and reacted for 15 minutes. Thereafter, the polymerization reaction was stopped using ethanol, and 45 ml of a solution containing 0.3 wt% IR1520 (BASF) as an antioxidant in n-hexane was added. The resulting polymer was placed in hot water heated with steam and stirred to remove the solvent, thereby producing a modified conjugated diene polymer.

Comparative Example 2

In Comparative Example 1, a modified conjugated diene polymer was prepared in the same manner as in Comparative Example 1, except that 16.5 mmol of 3-(dimethoxy(methyl)silyl)-N,N-diethylpropan-1-amine was added.

Comparative Example 3

In Comparative Example 1, a modified conjugated diene polymer was prepared in the same manner as in Comparative Example 1, except that 2.5 mmol of 3-(dimethoxy(methyl)silyl)-N,N-diethylpropan-1-amine was added.

Comparative Example 4

In the first reactor of the continuous reactor in which two reactors are connected in series, a styrene solution containing 60 wt% styrene dissolved in n-hexane was injected at a rate of 1.85 kg/h, a 1,3-butadiene solution containing 60 wt% 1,3-butadiene dissolved in n-hexane was injected at a rate of 11.9 kg/h, a 48.0 kg/h n-hexane solution containing 2.0 wt% 1,2-butadiene dissolved in n-hexane was injected at a rate of 40.0 g/h, a 10 wt% 2,2-(di-2(tetrahydrofuryl)propane as a polar additive was dissolved in n-hexane was injected at a rate of 61.0 g/h, and a n-butyllithium solution containing 6.6 wt% n-butyllithium dissolved in n-hexane was injected at a rate of 106.1 g/h. At this time, The temperature of the first reactor was maintained at 55°C, and when the polymerization conversion rate reached 48%, the polymer was transferred from the first reactor to the second reactor through the transfer pipe.

Next, a 1,3-butadiene solution containing 60 wt% of 1,3-butadiene dissolved in n-hexane was injected into the second reactor at a rate of 2.96 kg/h. At this time, the temperature of the second reactor was maintained at 65°C, and the reaction was terminated when the polymerization conversion rate was 95% or higher.

After this, a solution of IR1520 (BASF) dissolved at 30 wt% as an antioxidant was injected into the polymerization solution discharged from the second reactor at a rate of 167 g/h and stirred. The resulting polymer was placed in hot water heated by steam and stirred to remove the solvent, thereby producing an unmodified conjugated diene polymer.

Comparative Example 5

In the first reactor of the continuous reactor with three reactors connected in series, a styrene solution containing 60 wt% styrene dissolved in n-hexane was injected at a rate of 1.85 kg/h, a 1,3-butadiene solution containing 60 wt% 1,3-butadiene dissolved in n-hexane was injected at a rate of 11.9 kg/h, a 48.0 kg/h n-hexane solution containing 2.0 wt% 1,2-butadiene dissolved in n-hexane was injected at a rate of 40 g/h, a 10 wt% 2,2-(di-2(tetrahydrofuryl)propane as a polar additive was dissolved in n-hexane was injected at a rate of 61.0 g/h, and a n-butyllithium solution containing 6.6 wt% n-butyllithium dissolved in n-hexane was injected at a rate of 106.1 g/h. At this time, The temperature of the first reactor was maintained at 50°C, and when the polymerization conversion rate reached 39%, the polymer was transferred from the first reactor to the second reactor through the transfer pipe.

Next, a 1,3-butadiene solution containing 60 wt% of 1,3-butadiene dissolved in n-hexane was injected into the second reactor at a rate of 2.96 kg/h. At this time, the temperature of the second reactor was maintained at 65°C, and when the polymerization conversion rate was 95% or higher, the polymer was transferred from the second reactor to the third reactor through a transfer pipe.

The polymer was transferred from the second reactor to the third reactor, and a solution containing 20 wt% of 1,4-bis(3-(triethoxysilyl)propyl)piperazine as a denaturant was introduced into the third reactor at a rate of 64.0 g/h. The temperature of the third reactor was maintained at 65°C.

After this, a solution of IR1520 (BASF) dissolved at 30 wt% as an antioxidant was injected at a rate of 167 g/h into the polymerization solution discharged from the third reactor and stirred. The resulting polymer was placed in hot water heated by steam and stirred to remove the solvent, thereby producing a modified conjugated diene polymer.

Comparative Example 6

In Example 1, when the polymerization conversion reached 47%, the polymer was transferred from the first reactor to the second reactor through the transfer pipe, and instead of 1,4-bis(3-(triethoxysilyl)propyl)piperazine as a modifier, a solution of 2 wt% dichlorodimethylsilane dissolved in n-hexane was introduced into the third reactor at a rate of 40 g/h, except that the same procedure as in Example 1 was repeated to produce a modified conjugated diene polymer.

Comparative Example 7

In Example 1, the reaction temperature was maintained at 75°C in the first reactor, 80°C in the second reactor, and 80°C in the third reactor, and when the polymerization conversion rate in the first reactor reached 55%, the polymer was transferred from the first reactor to the second reactor through a transfer pipe for polymerization, except that the same procedure as in Example 1 was performed to produce a modified conjugated diene polymer.

Experimental Example 1

For each modified or unmodified conjugated diene polymer manufactured in the above examples and comparative examples, the styrene unit content and vinyl content, and the weight average molecular weight (Mw, X10 ³ g/mol), number average molecular weight (Mn, X10 ³ g/mol), molecular weight distribution (PDI, MWD), coupling number, Mooney viscosity (MV), Mooney relaxation rate, shrinkage factor, Si content, and N content in the polymer were measured, respectively. The results are shown in Table 1 below.

1) Styrene units and vinyl content (weight %)

The styrene unit (SM) and vinyl content in each of the above polymers were measured and analyzed using a Varian VNMRS 500 MHz NMR.

In the NMR measurement, 1,1,2,2-tetrachloroethane was used as the solvent, and the solvent peak was calculated as 5.97 ppm. 7.2–6.9 ppm was the peak of random styrene, 6.9–6.2 ppm was the peak of block styrene, 5.8–5.1 ppm was the peak of 1,4-vinyl, and 5.1–4.5 ppm was the peak of 1,2-vinyl, and thus the styrene unit and vinyl content were calculated.

2) Weight average molecular weight (Mw, X10 ³ g/mol), number average molecular weight (Mn, X10 ³ g/mol), molecular weight distribution (PDI, MWD) and coupling number (CN)

Through GPC (Gel permeation chromatography) analysis, the weight average molecular weight (Mw) and number average molecular weight (Mn) were measured, and a molecular weight distribution curve was obtained. In addition, the molecular weight distribution (PDI, MWD, Mw/Mn) was obtained by calculating from each measured molecular weight. Specifically, the GPC was performed by combining two PLgel Olexis (Polymer Laboratories) columns and one PLgel mixed-C (Polymer Laboratories) column, and PS (polystyrene) was used as the GPC standard material when calculating the molecular weight. The GPC measurement solvent was prepared by mixing 2 wt% of an amine compound into tetrahydrofuran. The molecular weight distribution curves obtained at this time are shown in Figs. 1 to 4.

In addition, the coupling number was calculated by obtaining the peak molecular weight (Mp ₁ ) of the polymer by collecting some polymers before adding the modifier or coupling agent in each example and comparative example, and then obtaining the peak molecular weight (Mp ₂ ) of each modified conjugated diene polymer, using the following mathematical formula 3.

[Mathematical Formula 3]

Coupling number (CN) = Mp ₂ / Mp ₁

3) Muni viscosity and Muni relaxation rate

The above Mooney viscosity (MV, (ML1+4, @100℃) MU) was measured using MV-2000 (ALPHA Technologies) at 100℃, Rotor Speed 2±0.02 rpm, Large Rotor. The sample used was left at room temperature (23±3℃) for more than 30 minutes, and 27±3 g was collected and filled into the die cavity, and the Platen was operated for 4 minutes to measure.

After measuring the Mooney viscosity, the slope value of the Mooney viscosity change that appears when the torque is released was measured, and the absolute value, the Mooney relaxation rate, was obtained.

4) Si content

The above Si content was measured using an inductively coupled plasma optical emission spectrometer (ICP-OES; Optima 7300DV) as an ICP analysis method. Specifically, about 0.7 g of the sample was placed in a platinum crucible, about 1 mL of concentrated sulfuric acid (98 wt%, electronic grade) was added, heated at 300°C for 3 hours, and the sample was annealed in an electric furnace (Thermo Scientific, Lindberg Blue M) using the following program of steps 1 to 3,

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(holdtime) 370℃ (2hr)

3) step 3: initial temp 370℃, rate (temp/hr) 47 ℃/hr, temp(holdtime) 510℃ (3hr)

1 mL of concentrated nitric acid (48 wt%) and 20 ㎕ of concentrated hydrofluoric acid (50 wt%) were added to the residue, the platinum crucible was sealed and shaken for more than 30 minutes, 1 mL of boric acid was added to the sample and stored at 0°C for more than 2 hours, then the sample was diluted in 30 mL of ultrapure water, incinerated, and measured.

5) N content

N content was measured using a trace nitrogen quantitative analyzer (NSX-2100H) by the NSX analysis method. Specifically, the trace nitrogen quantitative analyzer (Auto sampler, Horizontal furnace, PMT & Nitrogen detector) was turned on and the carrier gas flow rates were set to 250 ml/min for Ar, 350 ml/min for O ₂ , and 300 ml/min for ozonizer, and the heater was set to 800℃. The analyzer was then allowed to stabilize for about 3 hours. After the analyzer stabilized, a calibration curve was created using a nitrogen standard (AccuStandard S-22750-01-5 ml) with calibration curve ranges of 5 ppm, 10 ppm, 50 ppm, 100 ppm, and 500 ppm, and the Area corresponding to each concentration was obtained, and a straight line was created using the ratio of the Area to the concentration. After that, a ceramic boat containing 20 mg of the sample was placed on the Auto sampler of the analyzer and measured to obtain the area. The N content was calculated using the area of the obtained sample and the calibration curve.

6) Contraction factor (g')

The shrinkage factor was calculated by injecting a sample into a GPC-light scattering measuring device (Viscotek TDAmax, Malvern) equipped with a light scattering detector and a viscosity detector, obtaining the absolute molecular weight from the light scattering detector, and obtaining the intrinsic viscosity [η] for the absolute molecular weight from the light scattering detector and the viscosity detector. Then, the intrinsic viscosity [η] ₀ of the linear polymer for the absolute molecular weight was calculated using the following mathematical equation 2, and the average value of the ratio of the intrinsic viscosities corresponding to each absolute molecular weight ([η] / [η] ₀ ) was expressed as the shrinkage factor. At this time, the eluent used was a mixed solution of tetrahydrofuran and N,N,N',N'-tetramethylethylenediamine (adjusted by mixing 20 mL of N,N,N',N'-tetramethylethylenediamine in 1 L of tetrahydrofuran), the column used PL Olexix (Agilent Corporation), and the measurement was performed under the conditions of an oven temperature of 40°C and a THF flow rate of 1.0 mL/min, and the sample was prepared by dissolving 15 mg of the polymer in 10 mL of THF.

[Mathematical formula 2]

[η] ₀ =10 ^-3.883 M ^0.771

In the above mathematical expression 2, M is the absolute molecular weight.

In Table 1 above, the specific materials of the initiator, modifier, and coupling agent are as follows.

* Modified monomer M1: 1-vinyl imidazole

* Modifier F1: 1,4-bis(3-(triethoxysilyl)propyl)piperazine)

* Modifier F2: 1-(3-(ethoxydimethylsilyl)propyl-4-(3-(triethoxysilyl)propyl)piperazine

* Modifier F3: 1-(3-(ethoxydimethylsilyl)propyl)-4-((triethoxysilyl)methyl)piperazine

* Modifier F4: 1,1,1-trimethoxy-N-((triethoxysilyl)methyl)-N-((4-((trimethylsilyl)methyl)piperazine-1-yl)methyl)silanamine

* Modifier F5: 1,1,3,3-tetramethoxy-1,3-bis(2-(4-methylpiperazine-1-yl)ethyl)disiloxane

* Modifier F6: 3-(dimethoxy(methyl)silyl)-N,N-diethylpropane-1-amine

* Coupling agent C1: Dichlorodimethylsilane

As shown in Table 1 above, it can be confirmed that the modified conjugated diene polymers of Examples 1 to 5 according to one embodiment of the present invention have a unimodal molecular weight distribution curve by gel permeation chromatography (see FIG. 1), a PDI (molecular weight distribution) of 1.0 or more and less than 1.7, a Mooney relaxation rate of 0.7 or more, and a shrinkage factor of 0.8 or more. On the other hand, it can be confirmed that the unmodified or modified conjugated diene polymers of Comparative Examples 1 to 7 have a bimodal molecular weight distribution curve by gel permeation chromatography (see FIG. 2), or exhibit a Mooney relaxation rate of less than 0.7 or a shrinkage factor of less than 0.8, and in particular, Comparative Example 7, which is manufactured by continuous polymerization but has a polymerization conversion rate in the first reactor outside the range of the present invention, exhibits a PDI value exceeding 1.7 and a Mooney relaxation rate and a shrinkage factor of less than 0.7 and 0.8, respectively, which are significantly reduced compared to the examples.

In addition, in the case of Comparative Example 1 in which a polymer was manufactured by the batch polymerization method of the present invention, the molecular weight distribution curve by gel permeation chromatography showed a bimodal shape (see FIG. 2). On the other hand, as in Comparative Examples 2 and 3, although the batch polymerization method was applied, the molecular weight distribution curve can be adjusted to have a unimodal shape (see FIGS. 3 and 4). However, in this case, the coupling number of the polymer is 1.0 or 2.0, respectively, and only the case in which the entire polymer is not coupled by the modifier (Comparative Example 2) and the case in which the majority of the polymer is coupled by the modifier (Comparative Example 3) can exist. Therefore, there is a difference in structure and properties from the unimodal polymer according to the continuous polymerization method of the present invention. Accordingly, it can be confirmed through Table 3 described below that the processability, tensile properties, and viscoelastic properties are significantly reduced compared to the examples.

Meanwhile, the modified conjugated diene polymers of Comparative Examples 5 and 6 were manufactured at the same level as the examples according to the present invention, except for the application of the modified monomer during polymerization and the type of the modifier, and the polymer properties such as molecular weight distribution, coupling number, Mooney relaxation rate, and shrinkage factor showed similar levels to the examples. However, since they did not include the functional group derived from the modified monomer or modifier presented in the present invention, the compatibility with the filler was poor, and this can be confirmed through the fact that the tensile properties and viscoelastic properties of Comparative Examples 5 and 6 were significantly reduced compared to the examples in Table 3 described below.

Experimental example 2

In order to compare and analyze the properties of the rubber compositions containing each modified or unmodified conjugated diene copolymer manufactured in the above examples and comparative examples and the molded articles manufactured therefrom, the tensile properties and viscoelastic properties were measured respectively and the results are shown in Table 3 below.

1) Manufacturing of rubber specimens

Each modified or unmodified conjugated diene polymer of the examples and comparative examples was mixed as raw rubber under the mixing conditions shown in Table 2 below. The contents of the raw materials in Table 2 are each part by weight based on 100 parts by weight of the raw rubber.

Specifically, the above rubber specimen is kneaded through first-stage kneading and second-stage kneading. In the first-stage mixing, a semi-automatic mixer equipped with a temperature control device was used to mix raw rubber, silica (filler), an organosilane coupling agent (X50S, Evonik), a process oil (TDAE oil), a zincating agent (ZnO), stearic acid, an antioxidant (TMQ (RD) (2,2,4-trimethyl-1,2-dihydroquinoline polymer), an anti-aging agent (6PPD ((dimethylbutyl)-N-phenyl-phenylenediamine)), and wax (Microcrystaline Wax). At this time, the initial temperature of the mixer was controlled to 70°C, and after mixing was completed, the first mixture was obtained at a discharge temperature of 145°C to 155°C. In the second-stage mixing, the first mixture was cooled to room temperature, and then the first mixture, sulfur, a rubber accelerator (DPD (diphenylguanine)), and A vulcanization accelerator (CZ (N-cytohexyl-2-benzothiazylsulfenamide)) was added and mixed at a temperature of 100°C or lower to obtain a secondary compound. Afterwards, a rubber specimen was manufactured through a curing process at 160°C for 20 minutes.

2) Tensile properties

Tensile properties were measured by manufacturing each test piece according to the tensile test method of ASTM 412, and measuring the tensile strength at break and the tensile stress at 300% elongation (300% modulus) of the test piece. Specifically, the tensile properties were measured at room temperature at a speed of 50 cm/min using a Universal Test Machin 4204 (Instron) tensile tester.

3) Viscoelastic properties

Viscoelastic properties were measured using a dynamic mechanical analyzer (GABO Corporation) in Film Tension mode at a frequency of 10 Hz and at each measurement temperature (-60℃ to 60℃) to determine the tan δ value for dynamic deformation. In the measured values, the higher the low-temperature 0℃ tan δ value, the better the wet road resistance, and the lower the high-temperature 60℃ tan δ value, the less hysteresis loss and the better the low-pass resistance (fuel efficiency). However, Table 3 below shows the viscoelastic properties by specifying a reference value and then exponentiating it (%), so that a higher value means better.

4) Processability characteristics

The Mooney viscosity (MV, (ML1+4, @100℃) MU) of the secondary compound obtained during the manufacture of the above 1) rubber specimen was measured to compare and analyze the processability characteristics of each polymer. A lower Mooney viscosity measurement value indicates better processability characteristics.

Specifically, using MV-2000 (ALPHA Technologies), a Large Rotor with a Rotor Speed of 2±0.02 rpm at 100℃, each secondary compound was left at room temperature (23±3℃) for more than 30 minutes, and then 27±3 g was collected and filled into the die cavity, and the Platen was operated for measurement for 4 minutes.

In Table 3 above, the viscoelasticity characteristic results of Examples 1 to 5, Comparative Examples 1 to 3, and Comparative Examples 5 to 7 were expressed as an exponent (%) based on the measured value of Comparative Example 4.

As shown in Table 3 above, Examples 1 to 5 according to one embodiment of the present invention showed improved tensile properties, viscoelastic properties, and processability properties compared to Comparative Examples 1 to 7.

Meanwhile, it is known that it is very difficult to have a characteristic in which the tan δ value at 0°C is improved while the tan δ value at 60°C is improved at the same time in terms of viscoelastic properties. Therefore, it can be seen that Examples 1 to 4, which show an excellent level of tan δ at 0°C that is equivalent to or higher than that of the comparative examples while showing a remarkable improvement in tan δ at 60°C, have very excellent viscoelastic properties.

In addition, as shown in Table 3 above, in the case of Comparative Examples 2 and 3, which were manufactured through batch polymerization but had a unimodal molecular weight distribution curve, not only was the poor processability inherent in batch polymerization not improved, but also the compounding properties, such as tensile properties and viscoelastic properties, which are realized through conventional batch polymerization were significantly worse than those of the examples. Here, the poor processability inherent in batch polymerization can be confirmed through the results of Comparative Example 1, which was manufactured through conventional batch polymerization and had a bimodal molecular weight distribution curve.

Claims (15)

The molecular weight distribution curve by gel permeation chromatography (GPC) has a unimodal shape.
The molecular weight distribution (PDI; MWD) is 1.0 or more and less than 1.7,
A functional group derived from a modified monomer represented by the following chemical formula 1, and comprising a functional group derived from a piperazine-based modifier at at least one terminal,
The coupling number (CN) is 1<CN<F, where F is the number of functional groups of the modifier,
The modified monomer represented by the above chemical formula 1 is a compound represented by the following chemical formula 2,
The above piperazine-based modifier is a modified conjugated diene polymer selected from compounds represented by the following chemical formulas 4 to 6:
[Chemical Formula 1]

In the above chemical formula 1,
F ₁ is an amine-containing functional group, R ₁ is an alkenyl group having 2 to 10 carbon atoms,
[Chemical formula 2]

In the above chemical formula 2,
R ₂ is an alkenyl group having 2 to 10 carbon atoms,
[Chemical Formula 4]

In the above chemical formula 4,
R _a1 and R _a2 are each independently an alkylene group having 1 to 20 carbon atoms or -R _a7 [OR _a8 ] _n3 -, wherein R _a7 and R _a8 are each independently an alkylene group having 1 to 20 carbon atoms, n ₃ is an integer from 1 to 30,
R _a3 to R _a6 are each independently an alkyl group having 1 to 20 carbon atoms or an aryl group having 6 to 20 carbon atoms,
n ₁ and n ₂ are integers independently selected from 0 to 3, and n ₁ +n ₂ is an integer greater than or equal to 1,
[Chemical Formula 5]

In the above chemical formula 5,
R _b1 is an alkyl group having 1 to 10 carbon atoms, -R _b19 SiR _b9 R _b10 R _b11 or -R _b12 A, wherein R _b9 to R _b11 are each independently an alkyl group having 1 to 10 carbon atoms, R _b12 is an alkylene group having 1 to 10 carbon atoms, R _b19 is a single bond or an alkylene group having 1 to 10 carbon atoms, and A is a substituent represented by the following chemical formula 5a,
R _b2 to R _b4 are independently an alkylene group having 1 to 10 carbon atoms,
R _b5 to R _b8 are independently an alkyl group having 1 to 10 carbon atoms,
m ₁ and m ₂ are independently integers from 1 to 3,
[Chemical formula 5a]

In the above chemical formula 5a, R _b13 and R _b14 are each independently an alkylene group having 1 to 10 carbon atoms, R _b15 to R _b18 are each independently an alkyl group having 1 to 10 carbon atoms, m ₃ and m ₄ are each independently an integer of 1 to 3,
[Chemical formula 6]

In the above chemical formula 6,
A ₁ and A ₂ are independently an alkylene group having 1 to 6 carbon atoms, which is unsubstituted or substituted with an alkyl group having 1 to 4 carbon atoms,
R _c1 to R _c4 are independently a halogen group or an alkoxy group having 1 to 6 carbon atoms,
R _c5 to R _c8 are independently an alkyl group having 1 to 3 carbon atoms,
o ₁ is an integer from 1 to 5, and o ₂ and o ₃ are, independently of each other, integers from 0 to 4.
delete In claim 1,
A modified conjugated diene polymer, wherein the modified monomer represented by the above chemical formula 1 is a compound represented by the following chemical formula 3.
[Chemical Formula 3]

delete In claim 1,
A modified conjugated diene polymer, wherein in the chemical formula 4, R _a1 and R _a2 are each independently an alkylene group having 1 to 10 carbon atoms or -R _a7 [OR _a8 ] _n3 -, wherein R _a7 and R _a8 are each independently an alkylene group having 1 to 10 carbon atoms, n ₃ is an integer of 1 to 30, R _a3 to R _a6 can each independently be an alkyl group having 1 to 10 carbon atoms, n ₁ and n ₂ are each independently an integer selected from 0 to 3, and n ₁ + n ₂ is an integer of 1 or more.
In claim 1,
In the chemical formula 5, R _b1 is an alkyl group having 1 to 6 carbon atoms, -R _b19 SiR _b9 R _b10 R _b11 or -R _b12 A, wherein R _b9 to R _b11 are each independently an alkyl group having 1 to 6 carbon atoms, R _b12 is an alkylene group having 1 to 6 carbon atoms, R _b19 is a single bond or an alkylene group having 1 to 6 carbon atoms, A is a substituent represented by chemical formula 5a, R _b2 to R _b4 are each independently an alkylene group having 1 to 6 carbon atoms, R _b5 to R _b8 are each independently an alkyl group having 1 to 6 carbon atoms, m ₁ and m ₂ are each independently an integer of 1 to 3, and in chemical formula 3a, R _b13 and R _b14 are each independently an alkylene group having 1 to 6 carbon atoms, and R _b15 to R _b18 A modified conjugated diene polymer, wherein each independently represents an alkyl group having 1 to 6 carbon atoms, and m ₃ and m ₄ are each independently an integer of 1 to 3.
In claim 1,
A modified conjugated diene polymer, wherein in the chemical formula 6, A ₁ and A ₂ are each independently an alkylene group having 1 to 6 carbon atoms which is unsubstituted or substituted with an alkyl group having 1 to 4 carbon atoms, R _c1 to R _c4 are each independently a halogen group or an alkoxy group having 1 to 4 carbon atoms, R _c5 to R _c8 are each independently an alkyl group having 1 to 3 carbon atoms, o ₁ is an integer of 1 or 2, and o ₂ and o ₃ are each independently integers of 0 to 4.
In claim 1,
The above modified conjugated diene polymer has a number average molecular weight (Mn) of 1,000 g/mol to 2,000,000 g/mol, a weight average molecular weight (Mw) of 1,000 g/mol to 3,000,000 g/mol, and a peak average molecular weight (Mp) of 1,000 g/mol to 3,000,000 g/mol.
In claim 1,
The above modified conjugated diene polymer is a modified conjugated diene polymer having a Si content and a N content of 50 ppm or more based on weight, respectively.
In claim 1,
The above modified conjugated diene polymer is a modified conjugated diene polymer having a Mooney relaxation rate of 0.7 or more and 3.0 or less as measured at 100°C.
In claim 1,
The above modified conjugated diene polymer is a modified conjugated diene polymer having a shrinkage factor of 0.8 to 3.0 as determined by gel permeation chromatography-light scattering method measurement equipped with a viscosity detector.
delete A rubber composition comprising a modified conjugated diene polymer and a filler as described in claim 1.
In claim 13,
The rubber composition comprises 0.1 to 200 parts by weight of a filler based on 100 parts by weight of the modified conjugated diene polymer.
In claim 13,
A rubber composition wherein the above filler is a silica-based filler or a carbon black-based filler.