KR20190084641A - Diene copolymer and method for preparing the same - Google Patents

Abstract

The present invention relates to a conjugated diene copolymer having excellent mixing properties and improved processing ability, and to a preparation method thereof. The conjugated diene copolymer, represented by chemical formula 1: (SB)-B_1, comprises: a random copolymerization unit derived from an aromatic vinyl monomer and a conjugated diene monomer; and a conjugated diene monomer-derived block polymerization unit coupled to one end of the random copolymerization unit. The conjugated diene copolymer comprises the conjugated diene monomer-derived block polymerization unit at a specific ratio, thereby having excellent mixing properties such as tensile strength and viscoelasticity properties, and having improved processing ability.

Description

[0001] The present invention relates to a conjugated diene-based copolymer and a method for preparing the conjugated diene-based copolymer.

The present invention relates to a conjugated diene-based copolymer having improved formability and improved processability, and a process for producing the same.

In recent years, there has been a demand for a conjugated diene polymer having a low running resistance, excellent abrasion resistance and tensile properties as a rubber material for a tire, and also having adjustment stability represented by wet skid resistance.

In order to reduce the running resistance of the tire, there is a method of reducing the hysteresis loss of the vulcanized rubber. As the evaluation index of such vulcanized rubber, repulsive elasticity of 50 DEG C to 80 DEG C, Tan delta, Goodrich heat, and the like are used. That is, a rubber material having a large rebound resilience at that temperature or a small tan δ or Goodrich heat is preferable.

Natural rubbers, polyisoprene rubbers, polybutadiene rubbers, and the like are known as rubber materials having a small hysteresis loss, but these have a problem of low wet skid resistance. Recently, a conjugated diene (co) polymer such as styrene-butadiene rubber (hereinafter referred to as SBR) or a butadiene rubber having a controlled sheath content (hereinafter referred to as Low Cis-BR) was produced by emulsion polymerization or solution polymerization And is used as a rubber for a tire. Of these, the greatest advantage of solution polymerization over emulsion polymerization is that vinyl structure content and styrene content, which define rubber properties, can be arbitrarily controlled and molecular weight and physical properties, etc., can be controlled by coupling, It can be adjusted. Therefore, it is easy to change the structure of the finally prepared SBR or Low Cis-BR rubber, and it is possible to reduce the movement of the chain ends due to bonding or modification of the chain terminals and increase the bonding force with the filler such as silica or carbon black, SBR rubber is widely used as a rubber material for tires. When such a solution-polymerized SBR is used as a rubber material for a tire, by increasing the vinyl content in the SBR, the glass transition temperature of the rubber can be increased to control tire properties such as running resistance and braking force, have.

However, in the case of SBR, it is difficult to have good characteristics to workability with excellent running resistance, abrasion resistance, tensile property and adjustment stability, and in addition, in the case of high quality tires, not only the mechanical properties (wear resistance, tensile properties, Which is a very important characteristic.

Therefore, it is necessary to develop a rubber which can not only provide basic tire requisite properties, but also has excellent ease of compounding with a filler, that is, a rubber having a good balance between physical properties and processability.

US 4,397,994 A

SUMMARY OF THE INVENTION The present invention has been made to solve the problems of the prior art, and it is an object of the present invention to provide a conjugated diene copolymer having improved formability and improved processability.

Another object of the present invention is to provide a process for producing the conjugated diene-based copolymer.

In order to solve the above problems, the present invention provides a conjugated diene-based copolymer represented by the following formula (1), wherein the conjugated diene monomer-derived block polymerization unit is contained in an amount of more than 5 wt% and not more than 30 wt%

[Chemical Formula 1]

(SB) -B ₁

In Formula 1,

SB is an aromatic vinyl monomer and a conjugated diene monomer-derived random copolymer unit, and B ₁ is a conjugated diene monomer-derived block polymerization unit.

The present invention also relates to a process for producing a first polymer (step 1) by first polymerizing a first conjugated diene monomer and an aromatic vinyl monomer in the presence of an organometallic compound in a hydrocarbon solvent; And a step (2) of introducing a second conjugated diene monomer into the first polymerizate and a second polymerization, wherein the second conjugated diene monomer is charged at a time when the following formula (1) is satisfied: Based copolymer as described in the above item

[Equation 1]

(a: b) = (c: d)

In the above equation (1)

a: b is the weight ratio of the first conjugated diene monomer and the aromatic vinyl monomer in the first polymerization,

c: d is the weight ratio of the first conjugated diene monomer-derived unit to the aromatic vinyl monomer-derived unit in the first polymer.

The conjugated diene-based copolymer according to the present invention comprises an aromatic vinyl-based monomer and a conjugated diene-based monomer-derived random copolymerization unit and a conjugated diene-based monomer-derived block polymerization unit, wherein the conjugated diene- By including the unit at a specific ratio, the compounding properties such as tensile properties and viscoelastic properties can be improved and the workability can be improved.

Further, a method for producing a conjugated diene-based copolymer according to the present invention is a method for producing a conjugated diene-based copolymer, which comprises preparing a first polymerized material comprising an aromatic vinyl-based monomer and a conjugated diene-based monomer-derived random copolymerization unit, To prepare a conjugated diene-based copolymer having a structure in which a random copolymerization unit derived from an aromatic vinyl monomer and a conjugated diene monomer and a block polymerization unit derived from a conjugated diene monomer are bonded to one end of the random copolymerization unit can be easily produced have.

Hereinafter, the present invention will be described in detail in order to facilitate understanding of the present invention.

The terms and words used in the present specification and claims should not be construed in an ordinary or dictionary sense and the inventor can properly define the concept of the term to describe its invention in the best possible way It should be construed as meaning and concept consistent with the technical idea of the present invention.

The present invention provides a conjugated diene-based copolymer which is excellent in compounding properties such as tensile strength and viscoelastic characteristics and has improved processability.

The conjugated diene-based copolymer according to one embodiment of the present invention is represented by the following formula (1), and contains the block copolymerized units derived from the conjugated dienic monomer in an amount of more than 5 wt% and not more than 30 wt%.

[Chemical Formula 1]

(SB) -B ₁

In Formula 1,

SB is an aromatic vinyl monomer and a conjugated diene monomer-derived random copolymer unit, and B ₁ is a conjugated diene monomer-derived block polymerization unit.

In response to the demand for low fuel consumption for automobiles, a rubber material having low running resistance, excellent abrasion resistance and tensile characteristics as well as braking characteristics typified by wet skid resistance is required as a rubber material for a tire. Recently, It is possible to change easily and to reduce the movement of chain ends due to bonding or modification of chain ends and to increase bonding force with a filler such as silica or carbon black so that SBR rubber (hereinafter referred to as SSBR) It is widely used as a material. Such an SSBR is a random copolymer prepared by polymerizing an aromatic vinyl monomer and a conjugated diene monomer in the presence of an organometallic compound, but generally has an aromatic vinyl monomer block polymerization unit In this case, there is a problem that the elastic properties after crosslinking are deteriorated. Thus, a method of adding a randomizing agent (for example, a polar additive) to the end of the polymer chain to inhibit the formation of an aromatic vinyl monomer block polymerization unit has been used. However, if the amount of the aromatic vinyl monomer block It is difficult to inhibit the formation of polymerized units, and when the amount of the randomizing agent is increased, the vinyl content in the prepared copolymer is increased and the reaction rate is excessively increased, resulting in a problem that the branch is excessively increased in the polymerized polymer chain. In order to reduce such a problem, it is required to lower the reaction temperature or to add a conjugated diene monomer having a concentration of 5% or less (usually 2%) at the end of the polymerization step. It is not easy to suppress.

Accordingly, the present invention provides a resin composition comprising an aromatic vinyl monomer, a conjugated diene monomer-derived random copolymerization unit and a conjugated diene monomer-derived block polymerization unit, wherein the conjugated diene monomer-derived block unit is bonded to one end of the random copolymerization unit , Which has excellent processability and is improved in processability while having excellent compounding properties.

Specifically, the conjugated diene-based copolymer according to one embodiment of the present invention has a structure represented by the following formula (1), wherein the conjugated diene-based monomer-derived block polymerization units are contained in an amount of more than 5 wt%, 30 wt% % Or more and 30 wt% or less. That is, the conjugated diene-based copolymer contains an aromatic vinyl-based monomer and a conjugated diene-based monomer-derived random copolymerization unit and a conjugated diene-based monomer-derived block polymerization unit, wherein the conjugated diene- Wherein the conjugated diene monomer-derived block polymerization unit is contained in an amount of more than 5 wt%, not more than 30 wt%, or not more than 10 wt%, based on 100 wt% of the entire conjugated diene-based copolymer. To 30% by weight of the random copolymerization unit. Meanwhile, the conjugated diene-based copolymer according to one embodiment of the present invention may be one having the above structure by being produced by the following production method.

Herein, the aromatic vinyl monomer and the conjugated diene monomer-derived random copolymerization unit represented by SB in the above formula (1) represents a repeating unit formed by polymerization of an aromatic vinyl monomer and a conjugated diene monomer, and the aromatic vinyl monomer unit And a conjugated diene monomer-derived unit. Specifically, it may contain 20 to 45% by weight of an aromatic vinyl-based monomer unit and 55 to 80% by weight of a conjugated diene-based monomer-derived unit.

The random copolymerization unit derived from the aromatic vinyl monomer and the conjugated diene monomer may have a weight average molecular weight of 100,000 g / mol to 1,300,000 g / mol, specifically 200,000 g / mol to 1,000,000 g / mol or 300,000 g / mol to 800,000 g / mol.

The conjugated diene monomer-derived block polymerization unit represented by B ₁ in the above formula (1) represents a repeating unit formed by polymerization of a conjugated diene monomer, and may have a weight average molecular weight of 10,000 g / mol to 500,000 g / mol , Specifically from 20,000 g / mol to 400,000 g / mol or from 20,000 g / mol to 300,000 g / mol.

Meanwhile, in the present invention, the conjugated diene monomer may be, for example, 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, piperylene, 3- 1,3-butadiene, and 2-halo-1,3-butadiene (wherein halo means a halogen atom), and specifically may be 1,3-butadiene.

Examples of the aromatic vinyl monomer include styrene,? -Methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 1-vinylnaphthalene, 4-cyclohexylstyrene, 4- (p- Styrene, and 1-vinyl-5-hexyl naphthalene, and may be specifically styrene.

Also, the conjugated diene-based copolymer according to an embodiment of the present invention may have a Mooney viscosity difference (DELTA MV) of less than 12 as shown in the following formula (2). Specifically, the Mooney viscosity difference may be 1 or more and less than 12.

&Quot; (2) "

MV = CMV - PMV

In the formula (2), CMV (compound mooney viscosity) is a Mooney viscosity of a combination including a conjugated diene-based copolymer, a filler and a crosslinking agent, and PMV (polymer mooney viscosity) is a Mooney viscosity of a conjugated diene-based copolymer.

At this time, the conjugated diene-based copolymer may have a Mooney viscosity of 30 or more, specifically 40 to 150, more specifically 40 to 130.

Further, the Mooney viscosity difference indicates the compounding property of the conjugated diene-based copolymer, that is, the ease of blending with the filler, and the smaller the Mooney viscosity difference is, the better the workability of the conjugated diene-based copolymer is.

Here, the combination may be a mixture comprising a conjugated diene-based copolymer, a filler and a cross-linking agent, specifically, a second combination described in Experimental Example 2 to be described later, 1) production of a cross-linked rubber. The Mooney viscosity was measured using a Large Rotor of Monsanto MV2000E at a temperature of 100 ° C. and a rotor speed of 2 ± 0.02 rpm for 30 minutes or more at room temperature (23 ± 5 ° C.) ± 3 g was taken and filled in the die cavity, and the platen was operated to measure torque while applying torque.

In addition, the conjugated diene-based copolymer according to an embodiment of the present invention has a number average molecular weight (Mn) of 100,000 g / mol to 1,000,000 g / mol, specifically 200,000 g / mol to 800,000 g / mol, May have a weight average molecular weight (Mw) of 100,000 g / mol to 1,800,000 g / mol, specifically 200,000 g / mol to 1,300,000 g / mol, more specifically 300,000 g / mol, / mol to 1,000,000 g / mol, and a molecular weight distribution (Mw / Mn) of 1.0 to 3.0, 1.1 to 2.5, or 1.1 to 2.0.

In the present invention, the weight average molecular weight (Mw) and the number average molecular weight (Mn) are respectively molecular weights as polystyrene standards analyzed by gel permeation chromatography (GPC), molecular weight distribution (Mw / Mn) is also called polydispersity, (Mw / Mn) of the weight average molecular weight (Mw) to the number average molecular weight (Mn).

The conjugated diene-based copolymer may have a vinyl content of 10% or more, specifically 15% or more, more specifically 20% to 50%, based on the total copolymer weight. Within this range, the glass transition temperature Therefore, when the tire is applied to a tire, it is possible to satisfy not only physical properties required for a tire such as a running resistance and a braking force, but also an effect of reducing fuel consumption. Here, the vinyl content may refer to the content of the 1,2-added conjugated diene monomer, not 1,4-added to 100% by weight of the conjugated diene-based copolymer.

The present invention also provides a process for producing the conjugated diene-based copolymer.

According to an embodiment of the present invention, there is provided a method for preparing a polymer, comprising: (1) preparing a first polymerized product by first polymerizing a first conjugated diene monomer and an aromatic vinyl monomer in the presence of an organometallic compound in a hydrocarbon solvent; And a step (2) of adding a second conjugated diene-based monomer to the first polymerizate and performing a second polymerization, and the second conjugated diene-based monomer is charged at a time when the following formula (1) is satisfied do.

[Equation 1]

(a: b) = (c: d)

In the above equation (1)

a: b is the weight ratio of the first conjugated diene monomer and the aromatic vinyl monomer in the first polymerization,

c: d is the weight ratio of the first conjugated diene monomer-derived unit to the aromatic vinyl monomer-derived unit in the first polymer.

The step 1 is a step for preparing a first polymerized product comprising a random copolymerization unit derived from an aromatic vinyl monomer and a conjugated diene monomer, which comprises reacting a first conjugated diene monomer and an aromatic vinyl monomer in the presence of an organometallic compound in a hydrocarbon solvent Followed by first polymerization.

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

The first conjugated diene monomer may be the same as the conjugated diene monomer defined above and may be the same as the second conjugated diene monomer described below. In the present invention, the first conjugated diene monomer and the second conjugated diene monomer are the same materials but may be classified into 'first' and 'second' in order to clarify the difference in the charging time in the manufacturing method .

The amount of the first conjugated diene-based monomer, the second conjugated diene-based monomer, and the aromatic vinyl-based monomer may be suitably adjusted so as to prepare the conjugated diene-based copolymer as defined above. .

The organometallic compound 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, or 0.1 mmol to 1 mmol based on 100 g of the total monomer, and examples of the organometallic compound include methyllithium, Butyl lithium, t-butyl lithium, hexyl lithium, n-decyl lithium, t-octyl lithium, phenyl lithium, 1-naphthyl lithium, n-eicosyl lithium, 4 4-cyclopentyl lithium, naphthyl potassium, lithium alkoxide, sodium alkoxide, potassium alkoxide, lithium sulphonate, sodium silicate, potassium silicate, Sodium sulphonate, potassium sulphonate, lithium amide, sodium amide, callauamide and lithium isopropyl amide. Specifically, it may be n-butyllithium.

The first polymerization of step 1 may be performed by further adding a polar additive, and the polar additive may be added in an amount of 0.01 g to 2.0 g based on 100 g of the total of the monomers. Specifically, the polar additive may be added in an amount of 0.05 g to 1.0 g, more specifically 0.03 g to 0.5 g, based on 100 g of the total of the monomers.

The polar additive may be at least one selected from the group consisting of tetrahydrofuran, ditetrahydrofuryl propane, diethyl ether, cycloalcohol ether, dipropyl ether, ethylene dimethyl ether, ethylene dimethyl ether, diethylene glycol, dimethyl ether, tertiary butoxyethoxyethane bis 3-dimethylaminoethyl) ether, (dimethylaminoethyl) ethyl ether, trimethylamine, triethylamine, tripropylamine and tetramethylethylenediamine.

The production method according to an embodiment of the present invention can easily form a random copolymer by complementing the difference in the reaction rates when the first conjugated diene monomer and the aromatic vinyl monomer are copolymerized by using the polar additive .

The polymerization of Step 1 may be anionic polymerization, and may be a living anionic polymerization having an anionic active site at the polymerization end by a growth polymerization reaction with an anion. The polymerization in step 1 may be temperature-raising polymerization, isothermal polymerization or constant temperature polymerization (adiabatic polymerization), and the above-mentioned constant temperature polymerization may be carried out in the presence of an organometallic compound, And the temperature-raising polymerization may mean a polymerization method in which the temperature is increased by arbitrarily applying heat after the introduction of the organometallic compound. In the isothermal polymerization, after the organometallic compound is added, heat is applied May refer to a polymerization method in which heat is increased or heat is taken to maintain the temperature of the polymerizer at a constant level.

The first polymerization may be performed in a temperature range of -20 DEG C to 150 DEG C, specifically, in a temperature range of 0 DEG C to 120 DEG C, more specifically, 50 DEG C to 100 DEG C.

The above step 2 is a step in which the aromatic vinyl monomer and the conjugated diene monomer-derived random copolymerization unit and the conjugated diene monomer-derived block polymerization unit are contained, wherein the conjugated diene monomer-derived block polymerization unit is bonded to one end of the random copolymer unit Can be carried out by adding a second conjugated diene monomer to the first polymer and then polymerizing the second conjugated diene monomer.

At this time, the second conjugated diene monomer may be added in an amount such that the weight ratio of the first conjugated diene monomer to the first conjugated diene monomer is 7: 1 to 5: 3 (first conjugated diene monomer: second conjugated diene monomer) .

On the other hand, the second conjugated diene-based monomer may be added at the time when the formula (1) is satisfied.

In the above formula (1), a: b represents the weight ratio of the first conjugated diene monomer and the aromatic vinyl monomer in the first polymerization, that is, the amount (a) of the first conjugated diene monomer used in the first polymerization, C: d represents the weight ratio of the first conjugated diene monomer-derived unit and the aromatic vinyl monomer-derived unit in the first polymer, that is, the weight ratio of the aromatic vinyl monomer in the first polymer to the conjugated monomer (b) (D) of the aromatic vinyl monomer-derived units (c) and the conjugated diene monomer-derived units constituting the diene-based monomer-derived random copolymer unit.

Here, the above formula (1) represents the polymerization conversion ratio of the first conjugated diene monomer and the aromatic vinyl monomer used in the first polymerization. When the formula (1) is satisfied, the first conjugated diene monomer and the aromatic vinyl monomer Indicating that the monomer participates in polymerization and is converted into an aromatic vinyl-based monomer and a conjugated diene-based monomer-derived random copolymerization unit. Specifically, usually, the aromatic vinyl monomer has a slow reaction rate with respect to the conjugated diene monomer, so that the conjugated diene monomer is consumed faster than the aromatic vinyl monomer and is converted into a polymerization chain. Therefore, when the ratio of the unit derived from the conjugated diene monomer and the unit derived from the aromatic vinyl monomer is equal to the ratio of the conjugated diene monomer and the aromatic vinyl monomer used in the initial polymerization reaction after the polymerization reaction, the aromatic vinyl monomer is polymerized And may be exhausted. That is, the point of time when the above formula (1) is satisfied may be the point of time when the conversion ratio of the aromatic vinyl monomer is 100%, and may be the point of 97% to 100% including the error range (-3% .

At this time, the polymer c was taken out from the reactor during the polymerization and confirmed by NMR analysis.

On the other hand, the second polymerization may be carried out while maintaining the same conditions as the first polymerization.

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

The rubber composition may contain 0.1 to 100% by weight, specifically 20 to 90% by weight, of the modified conjugated diene polymer.

In addition, the rubber composition may further include other rubber components, if necessary, in addition to the modified conjugated diene polymer, wherein the rubber component may be contained in an amount of 90 wt% or less based on the total weight of the rubber composition. Specifically, it may be contained in an amount of 1 part by weight to 90 parts by weight based on 100 parts by weight of the modified conjugated diene-based copolymer.

The rubber component may be natural rubber or synthetic rubber, for example natural rubber (NR) comprising cis-1,4-polyisoprene; Modified natural rubbers such as epoxidized natural rubber (ENR), deproteinized natural rubber (DPNR), and hydrogenated natural rubber, which are modified or refined with the general natural rubber; Butadiene copolymers (SBR), polybutadiene (BR), polyisoprenes (IR), butyl rubbers (IIR), ethylene-propylene copolymers, polyisobutylene-co-isoprene, neoprene, poly Butadiene), poly (styrene-co-butadiene), poly (styrene-co-butadiene) Synthetic rubber such as polysulfide rubber, acrylic rubber, urethane rubber, silicone rubber, epichlorohydrin rubber, butyl rubber, halogenated butyl rubber and the like may be used, and any one or a mixture of two or more thereof may be used have.

In addition, the rubber composition may contain 0.1 to 200 parts by weight of a filler based on 100 parts by weight of the modified conjugated diene-based polymer. Specifically, the rubber composition may include 0.1 to 150 parts by weight of a filler. The filler may be a silica filler, a carbon black filler, or a combination thereof.

The carbon black filler is not particularly limited, but may have a nitrogen adsorption specific surface area (measured according to N ₂ SA, JIS K 6217-2: 2001) of 20 m 2 / g to 250 m 2 / g. The carbon black may have a dibutyl phthalate oil absorption (DBP) of 80 cc / 100 g to 200 cc / 100 g. If the nitrogen adsorption specific surface area of the carbon black exceeds 250 m ² / g, the workability of the rubber composition may deteriorate. If it is less than 20 m ² / g, the reinforcing performance by carbon black may be insufficient. If the DBP oil absorption of the carbon black exceeds 200 cc / 100 g, the workability of the rubber composition may decrease. If the DBP oil absorption is less than 80 cc / 100 g, the reinforcing performance by carbon black may be insufficient.

The silica is not particularly limited, but may be, for example, wet silica (hydrated silicic acid), dry silica (silicic anhydride), calcium silicate, aluminum silicate or colloidal silica. Specifically, the silica may be a wet silica having the most remarkable effect of improving the destructive property and the wet grip. Also, the silica has a nitrogen surface area per gram (N ₂ SA) of 120 m 2 / g to 180 m 2 / g and a cetyl trimethyl ammonium bromide (CTAB) adsorption specific surface area of 100 m 2 / / g. < / RTI > If the nitrogen adsorption specific surface area of the silica is less than 120 m < 2 > / g, the reinforcing performance by silica may be lowered. If it exceeds 180 m < 2 > / g, If the CTAB adsorption specific surface area of the silica is less than 100 m < 2 > / g, the reinforcing performance by the silica as a filler may be deteriorated. If it exceeds 200 m < 2 > / g, the workability of the rubber composition may deteriorate.

On the other hand, when silica is used as the filler, a silane coupling agent may be used together to improve the reinforcing property and the low heat build-up.

Specific examples of the silane coupling agent include bis (3-triethoxysilylpropyl) tetrasulfide, bis (3-triethoxysilylpropyl) trisulfide, 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 Triethoxysilylpropyl-N, N-dimethylthiocarbamoyltetrasulfide, 2-triethoxysilylethyl-N, N-dimethylthiocarbamoyltetrasulfide, 3-trimethoxysilyl Propylbenzothiazolyltetrasulfide, 3-triethoxysilylpropylbenzyltetrasulfide, 3-triethoxysilylpropylmethacrylate Monosulfide, monosulfide, 3-trimethoxysilylpropyl methacrylate monosulfide, bis (3-diethoxymethylsilylpropyl) tetrasulfide, 3-mercaptopropyldimethoxymethylsilane, dimethoxymethylsilylpropyl- N-dimethylthiocarbamoyltetrasulfide, or dimethoxymethylsilylpropylbenzothiazolyltetrasulfide. Any one or a mixture of two or more of them may be used. More specifically, in consideration of the reinforcing effect, the silane coupling agent may be bis (3-triethoxysilylpropyl) polysulfide or 3-trimethoxysilylpropyl benzothiazine tetrasulfide.

The silane coupling agent may be used in an amount of 1 part by weight to 20 parts by weight based on 100 parts by weight of the filler. When used in the above-mentioned range, gelation of the rubber component can be prevented while sufficiently exhibiting the effect as a coupling agent. More specifically, the silane coupling agent may be used in an amount of 5 parts by weight to 15 parts by weight based on 100 parts by weight of silica.

In addition, the rubber composition according to an embodiment of the present invention may be sulfur-crosslinkable and may further include a vulcanizing agent.

The vulcanizing agent may be specifically a 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. When contained in the above content range, the required elastic modulus and strength of the vulcanized rubber composition can be ensured, and at the same time, the low fuel consumption ratio can be obtained.

In addition, the rubber composition according to one embodiment of the present invention may contain various additives commonly used in the rubber industry, such as a vulcanization accelerator, a process oil, a plasticizer, an antioxidant, a scorch inhibitor, a zinc oxide, , Stearic acid, a thermosetting resin, or a thermoplastic resin.

The vulcanization accelerator is not particularly limited and specifically includes M (2-mercaptobenzothiazole), DM (dibenzothiazyl disulfide), CZ (N-cyclohexyl-2-benzothiazyl sulfenamide) Based compound, or a guanidine-based compound such as DPG (diphenylguanidine) can be used. The vulcanization accelerator may be included in an amount of 0.1 to 5 parts by weight based on 100 parts by weight of the rubber component.

The process oil may be a paraffinic, naphthenic or aromatic compound. More specifically, considering the tensile strength and abrasion resistance, the aromatic process oil may be a hysteresis process, Naphthenic or paraffinic process oils can be used when considering loss and low temperature characteristics. The process oil may be contained in an amount of 100 parts by weight or less based on 100 parts by weight of the rubber component. When the content is included in the above amount, the tensile strength and low heat build-up (low fuel consumption) of the vulcanized rubber can be prevented from lowering.

Specific examples of the antioxidant include N-isopropyl-N'-phenyl-p-phenylenediamine, N- (1,3-dimethylbutyl) -N'- 2, 4-trimethyl-1,2-dihydroquinoline, or high-temperature condensates of diphenylamine and acetone. The antioxidant may be used in an amount of 0.1 part by weight to 6 parts by weight based on 100 parts by weight of the rubber component.

The rubber composition according to one embodiment of the present invention can be obtained by kneading by using a kneader such as Banbury mixer, roll, internal mixer or the like by the above compounding formula. Further, the rubber composition can be obtained by a vulcanization step after molding, This excellent rubber composition can be obtained.

Accordingly, the rubber composition can be applied to various members such as tire tread, under-tread, sidewall, carcass-coated rubber, belt-coated rubber, bead filler, pancake or bead-coated rubber, vibration proof rubber, belt conveyor, And can be useful for the production of various industrial rubber products.

The molded article produced using the rubber composition may be one comprising a tire or tire tread.

Hereinafter, the present invention will be described in more detail with reference to Examples and Experimental Examples. However, the following examples and experimental examples are provided for illustrating the present invention, and the scope of the present invention is not limited thereto. In the following Examples and Comparative Examples, only one example is shown through batch type polymerization. However, this is for exemplifying the present invention, and the scope of the present invention is not limited to the batch type polymerization.

Example 1

160 g of styrene, 560 g of 1,3-butadiene and 4,533 g of n-hexane and 6.53 mmol of 2,2-di (2-tetrahydrofuryl) propane as a polar additive were introduced into a 20 L autoclave reactor, Lt; / RTI > When the internal temperature of the reactor reached 75 캜, 3.75 mmol of n-butyllithium was charged into the reactor, and the first adiabatic reaction was carried out for 30 minutes. 80 g of 1,3-butadiene was added thereto, and the second adiabatic heating reaction was carried out for 30 minutes while maintaining the temperature at 75 ° C. At this time, in the second adiabatic heating reaction, 1,3-butadiene was collected from the reactor after the first adiabatic heating reaction and subjected to NMR analysis. Then, the weight ratio of styrene and 1,3-butadiene used in the first adiabatic heating reaction And the weight ratio of the styrene-derived unit and the 1,3-butadiene-derived unit analyzed by NMR was the same (when the polymerization conversion ratio of styrene was 100%). Thereafter, the polymerization reaction was stopped using ethanol, and 1.0 part by weight of BHT (butylated hydroxytoluene) as an antioxidant was added. The resulting polymer was stripped of the solvent by steam stripping, and then the solvent and water were removed by removing the solvent and water by roll drying to prepare a conjugated diene-based copolymer.

Example 2

In the same manner as in Example 1 except that 400 g of 1,3-butadiene was used in the first adiabatic heating reaction and 240 g of 1,3-butadiene was used in the second adiabatic heating reaction, To prepare a conjugated diene-based copolymer (polymerization conversion rate of styrene: 99.8%).

Comparative Example 1

160 g of styrene, 640 g of 1,3-butadiene and 4,533 g of n-hexane and 6.53 mmol of 2,2-di (2-tetrahydrofuryl) propane as a polar additive were introduced into a 20 L autoclave reactor, Lt; / RTI > When the internal temperature of the reactor reached 75 캜, 3.75 mmol of n-butyllithium was charged into the reactor, and the first adiabatic reaction was carried out for 30 minutes. Thereafter, the polymerization reaction was stopped using ethanol, and 1.0 part by weight of BHT (butylated hydroxytoluene) as an antioxidant was added. The resulting polymer was stripped of the solvent by steam stripping, and then the solvent and water were removed by removing the solvent and water by roll drying to prepare a conjugated diene-based copolymer.

Comparative Example 2

In Example 1, the weight ratio of styrene and 1,3-butadiene used in the first adiabatic heating reaction of 1,3-butadiene in the second adiabatic raising reaction was measured by using a styrene-derived unit and a 1,3-butadiene-derived unit (Polymerization conversion of styrene: 96%) was prepared in the same manner as in Example 1, except that the weight ratio of styrene was changed to the same.

Comparative Example 3

The procedure of Example 1 was repeated except that 240 g of 1,3-butadiene was used in the first adiabatic heating reaction and 400 g of 1,3-butadiene was used in the second adiabatic heating reaction. To prepare a conjugated diene-based copolymer.

Comparative Example 4

The procedure of Example 1 was repeated except that 600 g of 1,3-butadiene was used in the first adiabatic heating reaction and 40 g of 1,3-butadiene was used in the second adiabatic heating reaction. To prepare a conjugated diene-based copolymer.

Experimental Example 1

Microstructure analysis, macrostructure analysis and molecular weight characteristics of each of the conjugated diene-based copolymers prepared in the above Examples and Comparative Examples were measured. The results are shown in Table 1 below.

1) Microstructure analysis

Microstructure analysis Varian VNMRS 500 Mhz NMR was used and 1,1,2,2-tetrachloroethane D2 (Cambridge Isotope) was used as a solvent.

2) Macro structure analysis

Macro structure analysis was performed by analyzing the Mooney viscosity and decay time.

The Mooney viscosity was measured using a MV-2000E (Monsanto) at a rotor speed of 2 ± 0.02 rpm and ML (1 + 4 at 100 ° C) using a large rotor. At this time, the sample was left at room temperature (23 ± 3 ° C) for more than 30 minutes, and then 27 ± 3 g was sampled and filled into the die cavity, and the platen was operated.

The decay time was measured as the decrease in the torque value with time after leaving the sample in the die cavity for 2 minutes under the condition that the rotor was stopped after the completion of the measurement of the Mooney viscosity and the torque value corresponding to the Mooney viscosity was 80% (Ie 20% torque value) was recorded as damping time. At this time, the larger the decay time, the better the elasticity of the conjugated diene-based copolymer. On the other hand, the increase of the decay time is caused by the increase of the molecular chain in the copolymer. When the decay time is increased to an appropriate value, the workability improves and positively affects the dispersion of the filler. However, The free end of the molecular chain of the molecule remains, which adversely affects the driving resistance. Therefore, it may be desirable to reflect this characteristic so that the decay time does not exceed two minutes.

3) Molecular weight characteristics

The weight average molecular weight (Mw), number average molecular weight (Mn) and molecular weight distribution (Mw / Mn) of the respective copolymers were measured and compared.

 Specifically, each of the copolymers was dissolved in tetrahydrofuran (THF) for 30 minutes at 40 ° C, and then loaded on gel permeation chromatography (GPC). At this time, two columns of PLgel Olexis column and one column of PLgel mixed-C column of Polymer Laboratories were used in combination. In addition, all of the new columns were of mixed bed type, and polystyrene was used as a gel permeation chromatography (GPC) standard material.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Microstructure analysis (NMR) Styrene
(SM, wt%) 20.1 19.9 20.0 20.4 20.3 20.1 Vinyl (wt%) 47.3 50.0 45.0 48.1 52.0 48.2 Macro structure analysis Mooney viscosity (PMV)
(ML (1 + 4) @ 100 C) 49.8 43.9 40.8 47.3 48.8 47.6 Decay time (min) 1.00 1.70 0.83 0.91 2.62 0.87 Molecular weight property Number average molecular weight (Mn, X10 ⁵ g / mol) 3.60 3.35 3.44 3.52 3.16 3.57 Weight average molecular weight (Mw, X10 ⁵ g / mol) 4.86 4.46 4.27 4.54 4.64 4.57 Molecular weight distribution (Mw / Mn) 1.35 1.33 1.24 1.29 1.47 1.28

Experimental Example 2

In order to comparatively analyze the physical properties of the rubber composition comprising the respective copolymers of the above Examples and Comparative Examples and the molded article produced therefrom, the Mooney viscosity, the viscoelastic characteristic and the tensile strength were measured. The results are shown in Table 3 below.

1) Preparation of crosslinked rubber

Each of the crosslinked rubbers was manufactured through a first stage kneading and a second stage kneading process, and the materials used in the first stage kneading and the second stage kneading process are shown in Table 2 below. At this time, the amount of the substance excluding the copolymer is shown based on 100 parts by weight of the copolymer.

In the first stage kneading, the above-mentioned copolymer, filler, process oil, antioxidant, zinc oxide (ZnO), stearic acid, and stearic acid are mixed by using an inter-meshing type Banbury mixer, Wax and an antioxidant were blended and kneaded in a first stage. At this time, the first stage kneading was performed by increasing the number of rotors, raising the internal temperature to 150, and maintaining the temperature for 260 seconds to obtain the first combination. In the second-stage kneading, the first combination was cooled to room temperature, and a rubber promoter, sulfur powder and vulcanization accelerator were added to the kneader, and the mixture was mildly mixed at 50 rpm for 40 seconds and 50 rpm. Of the second combination. Then, each crosslinked rubber was prepared by heating at 160 DEG C press for each time the respective second blend was multiplied by 1.3 times t'90 hours.

division Material name Weight portion First stage kneading Rubber Each copolymer 100 Filler Silica (7000 GR, Degussa) 70 Process oil TDAE 37.5 Silane coupling agent Z50S (Degussa)
(50 wt% carbon black + 50 wt% bis (3-triethoxysilylpropyltetrasulfane)) 11.2 Stearic acid Stearic acid 2.0 Zinc oxide Zinc oxide 3.0 Antioxidant RD (Flexsys)
(Polymerized 2,2,4-trimethyl-1,2-dihydroquinoline) 2.0 Antioxidant 6PPD (Flexsys)
(N-1,3-dimethylbutyl-N'-phenyl-p-phenylenediamine) 2.0 Wax Wax 1.0 Second stage kneading Rubber accelerator DPG (Flexsys)
(Diphenylguanidine) 1.75 Sulfur powder sulfur 1.5 Vulcanization accelerator CZ (Flexsys)
(Nt-butyl-2-benzothiazyl sulfonamide) 2.0

2) Mooney viscosity

The Mooney viscosity was measured using each second blend prepared during the preparation of the crosslinked rubber specimen. Specifically, ML (1 + 4) was measured at 100 ° C using a MV-2000E (Monsanto) with a rotor speed of 2 ± 0.02 rpm and a large rotor. At this time, the sample was left at room temperature (23 ± 3 ° C) for more than 30 minutes, and then 27 ± 3 g was sampled and filled into the die cavity, and the platen was operated.

3) Tensile properties

Each of the test pieces was prepared in accordance with the tensile test method of ASTM 412, and the tensile strength at the time of cutting the test piece, the tensile stress at 300% elongation (300% modulus) and elongation (%) were measured. Specifically, the tensile properties were measured at a rate of 50 cm / min at room temperature using a Universal Test Machine 4204 (Instron) tensile tester to obtain tensile strength and tensile stress values at 300% elongation.

4) Viscoelastic properties

The rolling resistance (60 캜 Tan δ) and the wet grip (0 Tan Tan δ) of each of the crosslinked rubbers prepared above were measured.

Specifically, the temperature was measured in a temperature sweep mode using an Explexor 500N (Gabo, Germany) at a frequency of 10 Hz, a static strain of 3.5%, and a dynamic strain of 3% . Each result is expressed as an index (percentage,%) with the value of Comparative Example 1 being 100.

division Example 1 Example 2 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Mooney viscosity
(Processability) The second combination (CMV) 60.7 51.0 55.9 59.6 50.4 62.4 Mooney viscosity 10.9 7.1 15.1 12.3 1.6 14.8 Index (%) 127.8 153.0 100 118.5 189.4 102.0 Tensile Properties 300% modulus (kgf / cm ² ) 111 109 106 150 103 108 The tensile strength
(kgf / cm ² ) 162 160 162 169 153 157 Elongation (%) 387 390 391 375 412 398 Viscoelastic properties Tan δ at 0
(Index,%) 110 125 100 105 138 103 Tan δ at 60
(Index,%) 103 95 100 97 85 99 Mooney Viscosity: Second Composition Mooney Viscosity (CMV) - Copolymer Mooney Viscosity (PMV) (see Table 1)

 As shown in Table 3, it was confirmed that Examples 1 and 2 according to one embodiment of the present invention have excellent balance of tensile properties, viscoelastic characteristics, and processability in comparison with Comparative Examples 1 to 4.

On the other hand, in Comparative Example 3, the workability was improved and the Tan δ value at 0 ° C was greatly increased compared with the Examples and other Comparative Examples. However, the tan δ value at 60 ° C was abruptly decreased to decrease the workability, tensile and viscoelastic properties . This is because the processability can be improved by increasing the proportion of the conjugated diene monomer-derived polymerization block located at least at one end of the aromatic vinyl monomer and the conjugated diene monomer-derived random copolymer block, The molecular chain in the polymer chain can be excessively increased, and the resistance to running can be rapidly lowered (see Table 1 and the decay time).

Claims (11)

A conjugated diene-based copolymer represented by the following formula (1) and containing a polymerization block derived from a conjugated diene-based monomer in an amount of more than 5 wt% and not more than 30 wt%
[Chemical Formula 1]
(SB) -B ₁
In Formula 1,
SB is a random copolymerization block derived from an aromatic vinyl monomer and a conjugated diene monomer, and B ₁ is a polymerization block derived from a conjugated diene monomer.
The method according to claim 1,
Wherein the conjugated diene-based copolymer contains 10 to 30% by weight of a polymerization block derived from a conjugated diene-based monomer.
The method according to claim 1,
Wherein the aromatic vinyl monomer and the conjugated diene monomer-derived random copolymer block contain 20 to 45% by weight of an aromatic vinyl monomer-derived unit and 55 to 80% by weight of a conjugated diene monomer-derived unit Copolymer.
The method according to claim 1,
Wherein the conjugated diene monomer-derived block polymerization unit and the conjugated diene monomer-derived block polymerization unit in the aromatic vinyl monomer and the conjugated diene monomer-derived random copolymer block have a weight ratio of 7: 1 to 5: 3.
The method according to claim 1,
Wherein the aromatic vinyl-based monomer and the conjugated diene-based monomer-derived random copolymer block have a weight average molecular weight of 100,000 g / mol to 1,300,000 g / mol.
The method according to claim 1,
Wherein the conjugated diene-based monomer-derived polymerization block has a weight average molecular weight of 10,000 g / mol to 500,000 g / mol.
The method according to claim 1,
Wherein the conjugated diene-based copolymer is a conjugated diene-based copolymer having a Mooney viscosity difference (? MV) represented by the following formula (2)
&Quot; (2) "
MV = CMV - PMV
In the above formula (2), CMV is the Mooney viscosity of the combination including the conjugated diene-based copolymer, the filler and the crosslinking agent, and PMV is the Mooney viscosity of the conjugated diene-based copolymer.
1) first polymerizing a first conjugated diene-based monomer and an aromatic vinyl-based monomer in the presence of an organometallic compound in a hydrocarbon solvent to prepare a first polymerized product; And
2) introducing a second conjugated diene-based monomer into the first polymerizer and performing a second polymerization,
Wherein the second conjugated diene-based monomer is charged at a time when the following formula (1) is satisfied: < EMI ID = 1.0 >
[Equation 1]
(a: b) = (c: d)
In the above equation (1)
a: b is the weight ratio of the first conjugated diene monomer and the aromatic vinyl monomer in the first polymerization,
c: d is the weight ratio of the first conjugated diene monomer-derived unit to the aromatic vinyl monomer-derived unit in the first polymer.
The method of claim 8,
Wherein the second conjugated diene monomer is added in an amount such that the weight ratio of the first conjugated diene monomer to the first conjugated diene monomer is from 7: 1 to 5: 3 (first conjugated diene monomer: second conjugated diene monomer) ≪ / RTI >
The method of claim 8,
Wherein the first polymerization of step 1) is carried out in the presence of a polar additive.
The method of claim 8,
Wherein the polar additive is added in an amount of 0.01 g to 2.0 g based on 100 g of the total of the monomers.