KR102736089B1 - Modified conjugated diene polymer, preparing method thereof, and rubber conposition comprising the same - Google Patents

Abstract

The present invention relates to a modified conjugated diene polymer having excellent affinity for a filler including a functional group derived from a compound represented by the chemical formula 1, a method for producing the same, a rubber composition including the same, and the compound. The present invention provides a modified conjugated diene polymer including a repeating unit derived from a conjugated diene monomer and a functional group derived from a compound represented by the chemical formula 1 at at least one terminal of the polymer.

Description

Modified conjugated diene polymer, preparation method thereof, and rubber composition comprising the same {MODIFIED CONJUGATED DIENE POLYMER, PREPARING METHOD THEREOF, AND RUBBER CONPOSITION COMPRISING THE SAME}

The present invention relates to a modified conjugated diene polymer having excellent affinity for a filler and including a functional group derived from a compound represented by chemical formula 1, a method for producing the same, a rubber composition comprising the same, and the compound.

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 a technology is being used to introduce a functional group to the chain terminal of the formed polymer by bonding it using various denaturing agents or modifying it. For example, U.S. Patent No. 4,397,994 proposes a technology to bond an active anion at the chain terminal of a polymer obtained by polymerizing styrene-butadiene in a nonpolar solvent using a monofunctional initiator, alkyl lithium, using a bonding agent such as a tin compound.

Meanwhile, as a modifier for introducing a functional group to the chain terminal of a polymer, a technology for applying an aminoalkoxysilane modifier containing both an alkoxysilane group and an amine group in the molecule to maximize the dispersibility and reactivity of the filler is widely known. However, there is a problem that when the number of amine groups in the modifier increases, the solubility in the hydrocarbon solvent used in polymer production decreases, making it difficult for the modification reaction to easily occur.

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 having excellent affinity with a filler and thus excellent processability, tensile properties, and viscoelastic properties by including a functional group derived from a compound represented by the above-mentioned chemical formula 1.

In addition, the present invention aims to provide a method for producing the modified conjugated diene polymer using a compound represented by chemical formula 1.

In addition, the present invention aims to provide a rubber composition comprising the modified conjugated diene polymer.

In addition, the present invention aims to provide a compound represented by chemical formula 1, which is useful for polymer modification and has excellent affinity with a filler, thereby improving the compounding properties of a conjugated diene polymer.

According to one embodiment of the present invention for solving the above problem, the present invention provides a modified conjugated diene polymer comprising a repeating unit derived from a conjugated diene monomer and a functional group derived from a compound represented by the following chemical formula 1 at at least one terminal of the polymer:

[Chemical Formula 1]

In the above chemical formula 1,

X is S or O,

R ₁ to R ₄ are independently an alkylene group having 1 to 20 carbon atoms, which is unsubstituted or substituted with a substituent, wherein the substituent is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms,

R ₇ and R ₁₆ are each independently an alkoxy group having 1 to 20 carbon atoms.

In addition, the present invention provides a method for producing the above-described modified conjugated diene polymer, comprising the steps of (S1) producing an active polymer by polymerizing a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer in the presence of a polymerization initiator in a carbon solvent; and (S2) reacting the active polymer with a compound represented by the chemical formula 1.

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

Auror, the present invention provides a compound represented by the following chemical formula 1:

[Chemical Formula 1]

In the above chemical formula 1,

X is S or O,

R ₁ to R ₄ are independently an alkylene group having 1 to 20 carbon atoms, which is unsubstituted or substituted with a substituent, wherein the substituent is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms,

R ₇ and R ₁₆ are each independently an alkoxy group having 1 to 20 carbon atoms.

The modified conjugated diene polymer according to the present invention may have excellent compatibility with a filler included in a rubber composition by including a functional group derived from a compound represented by the chemical formula 1, such as an amine group, an alkoxysilane group, an oxygen atom, or a sulfur atom, at at least one terminal of the polymer.

The method for producing a modified conjugated diene polymer according to the present invention can easily produce a modified conjugated diene polymer having excellent affinity with a filler by including a step of carrying out a modification reaction with a compound represented by chemical formula 1.

In addition, the compound represented by chemical formula 1 according to the present invention has high anionic reactivity and can easily react with the active site of the polymer, has low steric hindrance and thus has an excellent coupling effect between polymer chains, and can easily modify the polymer.

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.

In the present invention, the term 'alkoxy group' may mean all functional groups, atomic groups, or compounds in which hydrogen at the end of an alkyl group is replaced with an oxygen atom, such as methoxy, ethoxy, propoxy, and butoxy.

In the present invention, the terms 'derived unit', 'derived repeating 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 which comprises a functional group derived from a compound represented by chemical formula 1 and which has excellent affinity with a filler and, as a result, can provide a rubber composition having excellent processability, tensile properties, and viscoelastic properties.

A modified conjugated diene polymer according to one embodiment of the present invention comprises a repeating unit derived from a conjugated diene monomer, and is characterized in that it comprises a functional group derived from a compound represented by the following chemical formula 1 at at least one terminal of the polymer.

[Chemical Formula 1]

In the above chemical formula 1,

X is S or O,

R ₁ to R ₄ are independently an alkylene group having 1 to 20 carbon atoms, which is unsubstituted or substituted with a substituent, wherein the substituent is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms,

R ₇ and R ₁₆ are each independently an alkoxy group having 1 to 20 carbon atoms.

The modified conjugated diene polymer according to one embodiment of the present invention may be manufactured by a method similar to that in the manufacturing method described below, which includes a step of reacting with a compound represented by Chemical Formula 1, and a functional group derived from the compound represented by Chemical Formula 1 may be bonded to at least one terminal of the polymer.

Specifically, the modified conjugated diene polymer has at least one functional group derived from the compound, such as an amine group, an alkoxysilane group, oxygen or a sulfur atom, bonded to at least one terminal of the polymer, so that it can have excellent affinity with a filler such as a silica-based filler, and the processability of a rubber composition including the modified conjugated diene polymer can be excellent, and as a result, there is an effect of improving the tensile properties and viscoelastic properties of a molded article manufactured using the rubber composition, such as a tire.

Specifically, in the chemical formula 1, X is S or O, R ₁ to R ₄ are each independently an unsubstituted alkylene group having 1 to 10 carbon atoms, R ₇ to R ₁₆ can each independently be an alkoxy group having 1 to 10 carbon atoms, and more specifically, the compound represented by the chemical formula 1 can be at least one selected from the group consisting of compounds represented by the chemical formulas 1-1 to 1-4.

[Chemical Formula 1-1]

[Chemical Formula 1-2]

[Chemical Formula 1-3]

[Chemical Formula 1-4]

In the above chemical formulas 1-1 to 1-4, Me is a methyl group and Et is an ethyl group.

In addition, according to one embodiment of the present invention, the modified conjugated diene polymer includes a repeating unit derived from a conjugated diene monomer and a functional group derived from a compound represented by Chemical Formula 1, wherein the repeating unit derived from the conjugated diene monomer may mean a repeating unit formed when the conjugated diene monomer is polymerized, and the functional group derived from the compound may mean a functional group derived from a compound.

In addition, according to another embodiment of the present invention, the polymer may include a repeating unit derived from an aromatic vinyl monomer, and in this case, 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, and a functional group derived from a compound represented by Chemical Formula 1.

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.

In addition, when the polymer chain includes a repeating unit derived from an aromatic vinyl monomer, the modified conjugated diene polymer may include 50 to 95 wt%, 55 to 90 wt%, or 60 to 90 wt% of the conjugated diene monomer-derived repeating unit, and 5 to 50 wt%, 10 to 45 wt%, or 10 to 40 wt% of the aromatic vinyl monomer-derived repeating unit, and within this range, the rolling resistance, wet road resistance, and wear resistance are excellent.

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 polymer chain forming the skeleton of the modified conjugated diene polymer may be a random copolymer chain, in which case there is an excellent effect of balance between each physical 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 3.0 or less, or 1.1 or more to 2.5 or less, or 1.1 or more to 2.0 or less, and within this range, there is an effect in which the tensile properties and viscoelastic properties are excellent, and the balance between each property is excellent.

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.

Here, the Mooney viscosity may be measured using a Mooney viscometer. Specifically, it was measured using a Large Rotor of Monsanto MV2000E, under the conditions of 100℃ and a Rotor Speed of 2±0.02 rpm, after leaving the polymer at room temperature (23±5℃) for more than 30 minutes, 27±3 g was collected and filled into the die cavity, and the platen was operated to apply torque.

In addition, the modified conjugated diene polymer may have a 1,2-vinyl bond content of 5 wt% or more, 10 wt% or more, or 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.

In addition, the present invention provides a method for producing the modified conjugated diene polymer.

The method for producing the modified conjugated diene polymer according to one embodiment of the present invention is characterized by including a step (S1) of producing an active polymer by polymerizing 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; and a step (S2) of reacting the active polymer with a compound represented by the following chemical formula 1.

[Chemical Formula 1]

In the above chemical formula 1, X and R ₁ to R ₁₆ are as defined 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 conjugated diene monomer or the conjugated diene monomer and the aromatic vinyl 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.

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, cyclopentyl 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.

The above step (S2) is a step for producing a modified conjugated diene polymer by reacting an active polymer with a compound represented by Chemical Formula 1, wherein the reaction may be a modification or coupling reaction, and at this time, the modifier may be used in an amount of 0.01 mmol to 10 mmol based on 100 g of the total monomer. As another example, the modifier may be used in a molar ratio of 1:0.1 to 10, 1:0.1 to 5, or 1:0.1 to 1:3 based on 1 mol of the polymerization initiator of the above step (S1).

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 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.

As another example, the present invention provides a compound having a novel structure that is useful for modifying polymers, particularly conjugated diene polymers, and has excellent affinity for fillers, thereby imparting excellent compounding properties to the polymer.

The compound according to one embodiment of the present invention is characterized by being represented by the following chemical formula 1.

[Chemical Formula 1]

In the above chemical formula 1,

X is S or O,

R ₁ to R ₄ are independently an alkylene group having 1 to 20 carbon atoms, which is unsubstituted or substituted with a substituent, wherein the substituent is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms,

R ₇ and R ₁₆ are each independently an alkoxy group having 1 to 20 carbon atoms.

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.

Manufacturing example 1

A compound represented by chemical formula 1-1 was prepared through the method shown in the following reaction scheme 1.

[Reaction Formula 1]

In the above reaction scheme 1, Me is a methyl group.

Manufacturing example 2

A compound represented by chemical formula 1-2 was prepared through the method shown in the following reaction scheme 2.

[Reaction Formula 2]

In the above reaction scheme 2, Me is a methyl group.

Example 1

In a 20 L autoclave reactor, 3 kg of n-hexane, 270 g of styrene, 710 g of 1,3-butadiene, 0.05 g of n-butyllithium, and 1.29 g of 2,2-di(2-tetrahydrofuryl)propane as a polar additive were charged and the internal temperature of the reactor was adjusted to 60℃ and an adiabatic temperature-raising reaction was performed. After approximately 30 minutes, 20 g of 1,3-butadiene was charged to cap the polymer terminals with butadiene, and after approximately 10 minutes, the compound represented by the chemical formula 1-1 prepared in Manufacturing Example 1 as a modifier was charged and reacted for 15 minutes ([DTP]:[act. Li] = 1.5:1 molar ratio, [modifier]:[act. Li] = 0.5:1 molar ratio). Thereafter, the reaction was stopped using ethanol, and 33 g of a solution containing 30 wt% of Wingstay K, an antioxidant, in hexane was added. The resulting polymer was placed in hot water heated with steam and stirred to remove the solvent, and then roll-dried to remove the remaining solvent and water, thereby producing a modified styrene-butadiene copolymer.

Example 2

In Example 1, a modified styrene-butadiene copolymer was manufactured in the same manner as in Example 1, except that the compound represented by the chemical formula 1-2 manufactured in Manufacturing Example 2 was used as a modifier.

Example 3

In Example 2, a modified styrene-butadiene copolymer was manufactured in the same manner as in Example 2, except that the modifier was used in a molar ratio of [modifier]:[act. Li] = 0.25:1.

Comparative Example 1

A 20 L autoclave reactor was charged with 3 kg of n-hexane, 270 g of styrene, 710 g of 1,3-butadiene, 0.05 g of n-butyllithium, and 1.29 g of 2,2-di(2-tetrahydrofuryl)propane as a polar additive. The internal temperature of the reactor was adjusted to 60℃ and an adiabatic temperature-raising reaction was performed. After about 30 minutes, 20 g of 1,3-butadiene was added to cap the polymer terminals with butadiene, and tetrachlorosilane as a coupling agent was added and reacted for 15 minutes ([coupling agent]:[act. Li] = 0.25:1 molar ratio). After about 10 minutes, the reaction was stopped using ethanol, and 33 g of a solution containing 30 wt% of Wingstay K, an antioxidant, dissolved in hexane was added. The resulting polymer was placed in hot water heated with steam and stirred to remove the solvent, then roll-dried to remove the remaining solvent and water, thereby producing a styrene-butadiene copolymer.

Comparative Example 2

In Example 1, a modified styrene-butadiene copolymer was manufactured in the same manner as in Example 1, except that a compound represented by the following chemical formula i was used instead of the compound represented by the chemical formula 1-1.

[chemical formula i]

Comparative Example 3

In Example 3, a modified styrene-butadiene copolymer was manufactured in the same manner as in Example 3, except that a compound represented by the following chemical formula i was used instead of the compound represented by the chemical formula 1-2.

[chemical formula i]

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 in the polymer, as well as the weight average molecular weight (Mw, X10 ³ g/mol), number average molecular weight (Mn, X10 ³ g/mol), molecular weight distribution (PDI, MWD), and Mooney viscosity (MV) were measured. 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)

The weight average molecular weight (Mw) and number average molecular weight (Mn) were measured through GPC (Gel permeation chromatography) analysis, 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 using a combination of 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.

3) Mooney point

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.

division Example Comparative example 1 2 3 1 2 3 NMR
(weight%) SM 27 27 27 27 27 27 Vinyl 43 42 43 42 43 43 GPC Mw(X10 ³ g/mol) 66 63 89 56 65 86 Mn(X10 ³ g/mol) 40 42 52 37 40 51 PDI 1.61 1.55 1.72 1.61 1.64 1.68 Mooney Point (MV) 75 78 85 75 75 83

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 of the modified or unmodified conjugated diene polymers of the examples, comparative examples, and reference 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.

division raw material Content (weight parts) Stage 1 Mixing rubber 100 Silica 70 Coupling agent (X50S) 11.2 Fair trade 37.5 Zinc oxide 3 Stearic acid 2 Antioxidant 2 Anti-aging agent 2 Wax 1 2nd stage mixing sulfur 1.5 Rubber accelerator 1.75 Vulcanization accelerator 2

Specifically, the above rubber specimen is mixed through first-stage mixing and second-stage mixing. 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 curing process was performed at 160°C for 20 minutes to produce a rubber specimen.

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 for viscoelastic behavior for dynamic deformation at a frequency of 10 Hz and each measurement temperature (-60℃ to 60℃) using a dynamic mechanical analyzer (GABO Corporation) in Film Tension mode, and the tan δ value was confirmed. In the measurement results, 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, the result values in Table 3 are expressed as an index based on the result values of Comparative Example 1, so a higher value indicates 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.

division Example Comparative example 1 2 3 1 2 3 Tensile properties
(kgf/cm ² ) tensile strength 184 191 187 174 190 192 300% modulus 131 134 131 96 127 124 Viscoelastic properties tan δ(at 0℃) 114 115 112 100 112 110 tan δ(at 60℃) 127 129 126 100 125 120 Processability characteristics 59 55 56 75 62 62 Processability Characteristics Index 127 136 134 100 121 121

In the above Table 3, the tan δ at 60°C and the index of the processability characteristics of Examples 1 to 3 and Comparative Examples 2 and 3 were calculated using the following mathematical formula 1 based on the measured value of Comparative Example 1 as the reference value, and the tan δ at 0°C was calculated using the following mathematical formula 2.

[Mathematical Formula 1]

Index(%)=(reference value/measurement value)X100

[Mathematical formula 2]

Index(%)=(measurement value/reference value)X100

As shown in Table 3 above, Examples 1 to 3 showed significantly improved tensile properties, viscoelastic properties, and processability properties compared to Comparative Example 1, which is an unmodified styrene-butadiene copolymer. Through this, it can be seen that the modified conjugated diene polymer according to the present invention can have excellent affinity with a filler by including a functional group derived from the compound represented by Chemical Formula 1, and as a result, it can have the effect of greatly improving the processability properties, tensile properties, and viscoelastic properties.

In addition, Examples 1 to 3 showed improved tensile properties and viscoelastic properties compared to Comparative Examples 2 and 3, while also greatly improving processability properties. In this case, Comparative Examples 2 and 3 were manufactured under the same conditions as Examples 2 and 3, respectively, except that they were manufactured using a compound containing an amine group and an alkoxysilyl group but not a sulfur atom or an oxygen atom in the molecule as a modifier. Through this, it can be seen that the modified conjugated diene polymer according to the present invention can have excellent filler affinity and dispersibility by applying a compound containing an oxygen atom or a sulfur atom and an amine group and an alkoxysilyl group in the molecule as a modifier, and as a result, it can have the effect of further improving processability properties while having excellent tensile properties and viscoelastic properties.

Claims (14)

Contains a repeating unit derived from a conjugated diene monomer,
A modified conjugated diene polymer comprising a functional group derived from a compound represented by the following chemical formula 1 at at least one terminal of the polymer:
[Chemical Formula 1]

In the above chemical formula 1,
X is S or O,
R ₁ to R ₄ are independently an alkylene group having 1 to 20 carbon atoms, which is unsubstituted or substituted with a substituent, wherein the substituent is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms,
R ₇ to R ₁₆ are each independently an alkoxy group having 1 to 20 carbon atoms.
In the first paragraph,
In the above chemical formula 1, X is S or O,
R ₁ to R ₄ are independently an unsubstituted alkylene group having 1 to 10 carbon atoms,
A modified conjugated diene polymer, wherein R ₇ to R ₁₆ are each independently an alkoxy group having 1 to 10 carbon atoms.
In the first paragraph,
A modified conjugated diene polymer, wherein the compound represented by the chemical formula 1 is at least one selected from the group consisting of compounds represented by the following chemical formulas 1-1 to 1-4:
[Chemical Formula 1-1]

[Chemical Formula 1-2]

[Chemical Formula 1-3]

[Chemical Formula 1-4]

In the above chemical formulas 1-1 to 1-4, Me is a methyl group and Et is an ethyl group.
In the first paragraph,
A modified conjugated diene polymer further comprising a repeating unit derived from an aromatic vinyl monomer.
In the first paragraph,
A modified conjugated diene polymer having a number average molecular weight (Mn) of 1,000 to 2,000,000 g/mol, a weight average molecular weight (Mw) of 1,000 to 3,000,000 g/mol, and a peak average molecular weight (Mp) of 1,000 to 3,000,000 g/mol.
In the first paragraph,
A modified conjugated diene polymer having a molecular weight distribution of 1 to 5.
A step (S1) of producing an active polymer by polymerizing a conjugated diene monomer or a conjugated diene monomer and an aromatic vinyl monomer in the presence of a polymerization initiator in a carbon solvent; and
A method for producing a modified conjugated diene polymer of claim 1, comprising the step (S2) of reacting the active polymer with a compound represented by the following chemical formula 1:
[Chemical Formula 1]

In the above chemical formula 1,
X is S or O,
R ₁ to R ₄ are independently an alkylene group having 1 to 20 carbon atoms, which is unsubstituted or substituted with a substituent, wherein the substituent is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms,
R ₇ to R ₁₆ are each independently an alkoxy group having 1 to 20 carbon atoms.
In Article 7,
A method for producing a modified conjugated diene polymer, wherein the compound represented by the chemical formula 1 is used in an amount of 0.1 to 10 mol per 1 mol of a polymerization initiator.
In Article 7,
A method for producing a modified conjugated diene polymer, wherein the polymerization in the above step (S1) is performed by further adding a polar additive.
In Article 9,
A method for producing a modified conjugated diene polymer, wherein the polar additive is added in an amount of 0.001 g to 10 g based on 1 mmol of a polymerization initiator.
A rubber composition comprising a modified conjugated diene polymer and a filler as described in claim 1.
In Article 11,
A rubber composition comprising 0.1 to 200 parts by weight of a filler based on 100 parts by weight of the above-mentioned modified conjugated diene polymer.
A compound represented by the following chemical formula 1:
[Chemical Formula 1]

In the above chemical formula 1,
X is S or O,
R ₁ to R ₄ are independently an alkylene group having 1 to 20 carbon atoms, which is unsubstituted or substituted with a substituent, wherein the substituent is an alkyl group having 1 to 10 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms,
R ₇ to R ₁₆ are each independently an alkoxy group having 1 to 20 carbon atoms.
In Article 13,
The compound represented by the above chemical formula 1 is a compound selected from compounds represented by the following chemical formulas 1-1 to 1-4:
[Chemical Formula 1-1]

[Chemical Formula 1-2]

[Chemical Formula 1-3]

[Chemical Formula 1-4]

In the above chemical formulas 1-1 to 1-4, Me is a methyl group and Et is an ethyl group.