KR20220070823A - Copolymer, method of producing the same and rubber composition comprising the same - Google Patents

Abstract

The present invention relates to a copolymer comprising a repeating unit derived from a conjugated diene-based monomer and a repeating unit derived from an aromatic vinyl-based monomer, wherein the copolymer comprises: at least one functional group represented by chemical formula 1, a preparation method thereof, a rubber composition comprising the same. More specifically, the modified conjugated diene-based and aromatic vinyl-based copolymer of the present invention is represented by the chemical formula 1. A novel modified copolymer provided by the present invention can acquire an improved affinity for an inorganic filler such as silica by comprising the functional group represented by the chemical formula 1 of the present invention in a copolymer chain.

Description

Copolymer, method of producing the same, and rubber composition comprising the same

The present invention relates to a copolymer, a method for producing the same, and a rubber composition comprising the same, and more particularly, to a modified conjugated diene system modified with a novel structure having improved affinity with the inorganic filler of the present invention and excellent dispersibility, and It relates to an aromatic vinyl-based copolymer, a method for preparing the same, and a rubber composition having excellent processability including the same.

In response to the recent demand for low fuel consumption for automobiles, as a rubber material for tires, a conjugated diene-based polymer having low rolling resistance, excellent abrasion resistance, tensile properties, etc., and adjustment stability typified by wet skid resistance is required. Carbon black and silica are used as reinforcing fillers for tire treads. When silica is used as reinforcing fillers, low hysteresis and wet skid resistance are improved.

In particular, since it is desirable to have a low history in the manufacture of semi-finished products for tires, a number of methods for reducing the history are being studied. As an example, there is an attempt to obtain good interaction between the polymer and silica by modifying the structure of the diene polymer and/or copolymer by adding a functionalizing agent, coupling agent, or branching agent in the final step of anionic polymerization.

US Patent No. 5015692 proposes a method for improving the hysteresis of a rubber composition containing the elastomer by functionalizing the elastomer through a modifier such as a nitrogen compound or phosphoryl chloride. Nevertheless, silica compositions containing elastomers modified by this method still do not exhibit satisfactory processability and a satisfactory history for use as tire treads. In addition, inorganic fillers such as silica have a disadvantage of poor dispersibility due to low affinity with rubber, so that it is not necessary to use a separate silane coupling agent to improve dispersibility or impart a bond between silica and rubber. have.

Therefore, it is possible to obtain excellent dispersibility by preventing agglomeration between fillers as well as affinity to inorganic fillers, and furthermore, when included in a rubber composition, it is excellent in processability and in a copolymer that can reduce the hysteresis in the final product. There is a demand for

One aspect of the present invention is to provide a modified copolymer having improved compatibility with inorganic fillers and improved processability in rubber compositions.

Another aspect of the present invention is to provide a method for preparing the modified copolymer of the present invention.

Another aspect of the present invention is to provide a rubber composition comprising the modified copolymer of the present invention.

Another aspect of the present invention is to provide a tire manufactured from the rubber composition of the present invention with improved physical properties.

According to one aspect of the present invention, a repeating unit derived from a conjugated diene-based monomer; And a copolymer comprising a repeating unit derived from an aromatic vinylic monomer, wherein the copolymer is provided with a copolymer comprising at least one functional group represented by the following Chemical Formula 1:

[화학식 1]

[Formula 1]

(In Formula 1,

R ¹ , R ² and R ⁵ are each independently selected from the group consisting of hydrogen, a hydroxyl group, a hydroxy (C ₁ -C ₂₀ )alkyl group, and a straight-chain and branched (C ₁ -C ₂₀ )alkyl group,

R ³ and R ⁴ are each independently selected from the group consisting of N, S, O and Si;

R ⁶ and R ⁷ are each independently selected from the group consisting of hydrogen, a straight-chain and branched (C ₁ -C ₂₀ )alkyl group,

R ⁸ may be selected from the group consisting of straight-chain and branched (C ₁ -C ₂₀ )alkylene groups, or may form a single bond or a divalent linking group between N and Si; and

R ⁹ and R ¹⁰ are each independently selected from the group consisting of straight-chain and branched (C ₁ -C ₅ )alkyl groups).

According to another aspect of the present invention,

(a) preparing an active polymer by polymerizing an aromatic vinyl-based monomer and a conjugated diene-based monomer in a hydrocarbon solvent in the presence of an organic alkali metal compound; and

(b) there is provided a method for preparing a copolymer comprising the step of reacting the active polymer with a modifier of formula (3):

[화학식 3]

[Formula 3]

(In Formula 3,

R ¹ , R ² and R ⁵ are each independently selected from the group consisting of hydrogen, a hydroxyl group, a hydroxy (C ₁ -C ₂₀ )alkyl group, and a straight-chain and branched (C ₁ -C ₂₀ )alkyl group,

R ³ and R ⁴ are each independently selected from the group consisting of N, S, O and Si;

R ⁶ , R ⁷ , R ¹¹ and R ¹² are each independently selected from the group consisting of hydrogen, straight-chain and branched (C ₁ -C ₂₀ )alkyl groups,

R ⁸ may be selected from the group consisting of straight-chain and branched (C ₁ -C ₂₀ )alkylene groups, or may form a single bond or a divalent linking group between N and Si; and

R ⁹ and R ¹⁰ are each independently selected from the group consisting of straight-chain and branched (C ₁ -C ₅ )alkyl groups).

According to another aspect of the present invention, there is provided a rubber composition comprising the copolymer of the present invention and an inorganic filler.

According to another aspect of the present invention, there is provided a molded article prepared from the rubber composition of the present invention.

The novel modified copolymer provided by the present invention can obtain improved affinity for inorganic fillers such as silica by including the functional group represented by Formula 1 in the present invention in the copolymer chain. Furthermore, the effect of inhibiting aggregation between fillers in the rubber composition can be obtained by such a modified structure, and processability can be improved, and thus the physical properties of the final molded article can be improved. In particular, the structure of the copolymer modified by the present invention as described above may further contribute to the improvement of fuel efficiency.

Hereinafter, preferred embodiments of the present invention will be described with reference to the accompanying drawings. However, the embodiment of the present invention may be modified in various other forms, and the scope of the present invention is not limited to the embodiments described below.

In this specification, the term "includes" of any component means that other components may be further included, rather than excluding other components, unless otherwise stated.

As used herein, the term "hydrocarbon group" refers to a monovalent organic radical formed by removing a hydrogen atom from a hydrocarbon with a hydrocarbon group consisting only of carbon and hydrogen regardless of structure, such as an alkyl group, an aryl group, an alkylaryl group, an arylalkyl group, etc. not limited

In addition, the term “alkyl group” as used herein refers to a monovalent straight-chain, branched-chain or cyclic saturated hydrocarbon group composed of only carbon and hydrogen atoms, and includes a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, and an isobutyl group. group, t-butyl group, pentyl group, hexyl group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, and the like.

On the other hand, when forming a divalent linking group in the present invention, in this case, the linking group is an unsubstituted -(CH ₂ ) ₁ -hydrocarbon group or an alkyl having 1 to 10 carbon atoms which may include at least one unsaturated bond in the linking group. It could be a rengi. In this case, l may be an integer of 1 to 10.

The copolymer of the present invention (hereinafter, may be used interchangeably with the 'modified copolymer' and 'modified conjugated diene-based and aromatic vinyl-based copolymer of the present invention') can induce improved affinity with inorganic fillers, , it is also possible to secure excellent dispersibility by preventing re-agglomeration during polymerization. In addition, the semi-finished product for tires in an uncured state including the same can improve mechanical and dynamic properties of the final product while maintaining good processability.

More specifically, the modified copolymer of the present invention is a repeating unit derived from a conjugated diene-based monomer; and a repeating unit derived from an aromatic vinyl-based monomer, wherein the copolymer includes at least one functional group represented by Formula 1 below.

[화학식 1]

[Formula 1]

In Formula 1,

R ¹ , R ² and R ⁵ are each independently selected from the group consisting of hydrogen, a hydroxyl group, a hydroxy (C ₁ -C ₂₀ )alkyl group, and a straight-chain and branched (C ₁ -C ₂₀ )alkyl group,

R ³ and R ⁴ are each independently selected from the group consisting of N, S, O and Si;

R ⁶ and R ⁷ are each independently selected from the group consisting of hydrogen, a straight-chain and branched (C ₁ -C ₂₀ )alkyl group,

R ⁸ may be selected from the group consisting of straight-chain and branched (C ₁ -C ₂₀ )alkylene groups, or may form a single bond or a divalent linking group between N and Si; and

R ⁹ and R ¹⁰ are each independently selected from the group consisting of straight-chain and branched (C ₁ -C ₅ )alkyl groups.

The silica surface, which is an exemplary inorganic filler, contains a number of hydroxyl groups, and thus exhibits a weak bonding force with a copolymer made of only non-polar hydrocarbons. Copolymers can improve the dispersibility of inorganic fillers such as silica and improve their compatibility with inorganic fillers due to the structural properties of the copolymer.

Preferably, the functional group of Formula 1 is represented by Formula 2 below:

[화학식 2]

[Formula 2]

In this case, R ¹ , R ² and R ⁵ are hydrogen; R ³ and R ⁴ are O; R ⁶ , R ⁷ , R ⁹ and R ¹⁰ are each independently selected from the group consisting of straight-chain and branched (C ₁ -C ₅ )alkyl groups; R ⁸ is a single bond between N and Si or a hydrocarbon group of -(CH ₂ ) _l -, wherein l is an integer of 1 to 10; And at least one of M ¹ and M ² is a conjugated diene-based and aromatic vinyl-based copolymer, and when one of M ¹ and M ² is a conjugated diene-based and aromatic vinyl-based copolymer, the remainder is hydrogen, for example, M ¹ and M ² are each independently a conjugated diene-based copolymer and an aromatic vinyl-based copolymer.

That is, the modified copolymer of the present invention includes a case in which both M ¹ and M ² are conjugated diene-based and aromatic vinyl-based copolymers, as well as when one moiety of M ¹ and M ² is hydrogen.

The modified copolymer of the present invention preferably includes at least one functional group of Formula 1 in the middle of the chain of the copolymer, so that the rubber composition including it is prevented from aggregation between the inorganic fillers in the rubber composition, so that the dispersibility of the inorganic filler is improved. Accordingly, the fuel efficiency characteristics of a tire formed using the rubber composition including the same may be improved.

The copolymer of the present invention may be, for example, a conjugated diene-based and aromatic vinyl-based copolymer, and in more detail, the conjugated diene-based and aromatic vinyl-based copolymer may be represented by the following formula (4).

[화학식 4]

[Formula 4]

In Formula 4, x is preferably an integer of 500 to 5000, y is preferably an integer of 20 to 100, and the arrangement of the conjugated diene-based monomer and the aromatic vinyl-based monomer is limited to the arrangement of Formula 4 No, they may be randomly arranged random copolymers.

In the present specification, the 'monomer-derived repeating unit' may indicate a component, structure, or material itself derived from a monomer, and refers to a repeating unit formed in the polymer by participating in the polymerization reaction of the inputted monomer during polymerization of the polymer. can be one

Accordingly, in the present invention, the repeating unit derived from the conjugated diene-based monomer is 1,3-butadiene, isoprene, 1,3-pentadiene (piperylene), 2,3-dimethyl-1,3-butadiene, 1,3- Hexadiene, 2-methyl-1,3-pentadiene, 3,4-dimethyl-1,3-hexadiene, 4,5-diethyl-1,3-octadiene, 3-butyl-1,3-octa It may include at least one selected from the group consisting of diene, 2-phenyl-1,3-butadiene, piperylene and isoprene. Specifically, the conjugated diene-based monomer may be 1,3-butadiene.

The repeating unit derived from the conjugated diene-based monomer is included in an amount of 60% to 99% by weight, or 60% to 90% by weight, specifically 63% to 85% by weight based on the weight of the conjugated diene-based and aromatic vinyl-based copolymer. can

The repeating unit derived from the aromatic vinyl-based monomer is styrene, alphamethyl styrene, 3-methyl styrene, 4-methyl styrene, 4-propyl styrene, 1-vinyl naphthalene, 4-cyclohexyl styrene, 4-(paramethylphenyl) styrene and 1 -Vinyl-5-hexylnaphthalene may include one or more selected from the group consisting of. Specifically, the aromatic vinyl-based monomer may be styrene.

The repeating unit derived from the aromatic vinyl-based monomer may be included in an amount of 10 wt% to 40 wt%, specifically 15 wt% to 40 wt%, based on the weight of the conjugated diene-based and aromatic vinyl-based copolymer.

The monomer mixture may further include a comonomer copolymerizable with a conjugated diene-based monomer and/or an aromatic vinyl-based monomer. Such a comonomer may include, but is not limited to, an acid anhydride-based monomer, an acrylonitrile-based monomer, and the like.

The modified copolymer obtained by the present invention may have a Mooney viscosity of 40 or more, specifically 40 to 90, more specifically 50 to 80. Since the Mooney viscosity is proportional to the weight average molecular weight, there may be an effect of improving mechanical properties within the above range.

On the other hand, the modified copolymer has a weight average molecular weight (Mw) of 1,000 g/mol to 2,000,000 g/mol, specifically 10,000 g/mol to 1,900,000 g/mol, more specifically 100,000 g/mol to 1,800,000 g/mol can be

In addition, the modified copolymer may have a molecular weight distribution (Mw/Mn, MwD) of from 1.0 to 10, or from 1.0 to 7, specifically from 1.1 to 5, and more specifically from 1.1 to 4.

Further, the modified copolymer may have a vinyl content of 60 wt% or more, specifically 63 wt% or more, and more specifically 63 wt% to 99 wt%. The vinyl content is 1,2, not 1,4-addition to the aromatic vinyl-based monomer, based on 100% by weight of the copolymer consisting of a monomer having a vinyl group and an aromatic vinyl-based monomer during copolymerization of the conjugated diene-based monomer and the aromatic vinyl-based monomer - It means the content of the added conjugated diene-based monomer.

In the viscoelastic characteristics of the modified copolymer, when measured at 10 Hz through dynamic mechanical analysis (DMA) after silica mixing, the Tan δ value at 60° C. may be 0.15 or less, and rolling resistance within this range Alternatively, the rotation resistance (RR) is greatly improved.

The copolymer of the modified copolymer of the present invention in a state before modification may be obtained by polymerizing a conjugated diene-based monomer or copolymerizing a vinyl aromatic monomer and a conjugated diene monomer.

According to another aspect of the present invention, there is provided a method for producing the modified copolymer of the present invention.

The polymerization step of the conjugated diene-based polymer is a step of preparing an alkali metal-bonded active polymer by polymerizing an aromatic vinyl-based monomer and a conjugated diene-based monomer in the presence of an organometallic compound in a hydrocarbon solvent. It may include a step representing

In more detail, the method for preparing the modified conjugated diene-based and aromatic vinyl-based copolymer of the present invention may include the following steps:

(a) preparing an active polymer by polymerizing an aromatic vinyl-based monomer and a conjugated diene-based monomer in a hydrocarbon solvent in the presence of an organic alkali metal compound; and

(b) a method for preparing a copolymer comprising the step of reacting the active polymer with a modifier of formula (3):

[화학식 3]

[Formula 3]

In Formula 3,

R ¹ , R ² and R ⁵ are each independently selected from the group consisting of hydrogen, a hydroxyl group, a hydroxy (C ₁ -C ₂₀ )alkyl group, and a straight-chain and branched (C ₁ -C ₂₀ )alkyl group,

R ³ and R ⁴ are each independently selected from the group consisting of N, S, O and Si;

R ⁶ , R ⁷ , R ¹¹ and R ¹² are each independently selected from the group consisting of hydrogen, straight-chain and branched (C ₁ -C ₂₀ )alkyl groups,

R ⁸ may be selected from the group consisting of straight-chain and branched (C ₁ -C ₂₀ )alkylene groups, or may form a single bond or a divalent linking group between N and Si; and

R ⁹ and R ¹⁰ are each independently selected from the group consisting of straight-chain and branched (C ₁ -C ₅ )alkyl groups.

Preferably, in the copolymer, in Formula 3, R ¹ , R ² and R ⁵ are hydrogen; R ³ and R ⁴ are O; R ⁶ , R ⁷ , R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are each independently selected from the group consisting of straight-chain and branched (C ₁ -C ₅ )alkyl groups; and R ⁸ is a single bond between N and Si or a hydrocarbon group of -(CH ₂ ) _l -, wherein l is an integer of 1 to 10.

Specific details regarding the conjugated diene-based monomer and the aromatic vinyl-based monomer may be the same as those described above with respect to the modified copolymer in the present specification, and the amount of each monomer used is a unit derived from a conjugated diene-based monomer and an aromatic vinyl-based monomer in the copolymer. The derived unit may be appropriately adjusted and used within the range controlled within the aforementioned range.

The hydrocarbon solvent is not particularly limited, but may be, for example, at least one selected from the group consisting of n-pentane, n-hexane, n-heptane, isooctane, cyclohexane, toluene, benzene and xylene. The hydrocarbon solvent may be used as it is, but it is preferable to use it after removing moisture, oxygen, or catalyst toxic substances by passing through molecular sieves and/or activated alumina.

The polymerization of step (a) may include anionic polymerization of the conjugated diene-based monomer and the aromatic vinyl-based monomer. In this case, the modified conjugated diene-based and aromatic vinyl-based copolymers are polymerized by generating an active site by a growth reaction with an anion initiated by an anionic polymerization initiator detailed below. However, the polymerization step of the present invention is not limited thereto.

In this case, the anionic polymerization initiator may include at least one selected from the group consisting of organic alkali metal compounds such as an organic lithium compound, an organic sodium compound, an organic potassium compound, an organic rubidium compound, and an organic cesium compound. It preferably contains an organolithium compound useful for polymerization of 1,3-diene monomer as an anionic polymerization initiator.

Specifically, the organolithium compound includes a compound composed of a lithium cation and an anion of an aliphatic hydrocarbon group, an alicyclic hydrocarbon group or an aromatic hydrocarbon group. The aliphatic group is a linear or branched alkyl group having 1 to 10 carbon atoms, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, t-butyl, sec-butyl, n-amine, sec-amyl, n -hexyl, sec-hexyl, n-heptyl, n-octyl, n-nonyl, etc., and the alicyclic hydrocarbon group is an alicyclic hydrocarbon group having 5 to 10 carbon atoms, for example, a cyclohexyl group, a methylcyclohexyl group, an ethylcyclohexyl group , cycloheptyl group, cyclopentylmethyl group, methylcyclopentylethyl group, etc., and the aromatic hydrocarbon group is an aryl group having 6 to 10 carbon atoms, for example, a phenyl group, tolyl group, phenylethyl group, benzyl group, naphthyl group or phenylcyclohexyl group.

Preferably, the anionic polymerization initiator is methyllithium, ethyllithium, propyllithium, n-butyllithium, s-butyllithium, t-butyllithium, hexyllithium, n-decyllithium, t-octyllithium, phenyllithium, 1- Naphthyllithium, n-eicosyllithium, 4-butylphenyllithium, 4-tolylylithium, cyclohexyllithium, 3,5-di-n-heptylcyclohexyllithium, 4-cyclopentyllithium, naphthyl sodium, naphthyl Potassium and the like may be included.

On the other hand, the anionic polymerization initiator is 0.0001 parts by weight to 0.65 parts by weight, for example, 0.00012 parts by weight to 0.64 parts by weight, 0.0002 parts by weight to 0.32 parts by weight, 0.0003 parts by weight to 0.16 parts by weight based on 100 parts by weight of the total of the monomer mixture. may be included. In the above range, it may be possible to prepare a copolymer having a high molecular weight.

The polymerization may be anionic polymerization, specifically, living anionic polymerization in which an active site is obtained by a growth reaction by an anion. In addition, the polymerization may be an elevated temperature polymerization, isothermal polymerization, or adiabatic polymerization (constant temperature polymerization).

Here, the adiabatic polymerization refers to a polymerization method comprising the step of polymerization with heat of reaction by itself without optionally applying heat after the organometallic compound is added, and the temperature-rising polymerization is a temperature by optionally adding heat after adding the organometallic compound. It represents a polymerization method to increase the temperature, and the isothermal polymerization refers to a polymerization method in which the temperature of the polymer is maintained constant by increasing heat by applying heat after the organometallic compound is added, or by taking heat away.

The polymerization may be carried out in a temperature range of -20 °C to 200 °C, specifically, in a temperature range of 0 °C to 150 °C, and more specifically in a temperature range of 10 °C to 120 °C.

In the polymerization of the copolymer in the state before modification, it may be polymerized by adding a polar additive. As such, the step polymerization may be performed by further adding a polar additive as needed, and the polar additive is 0.005 g to 10 g, specifically 0.007 g to 7 g, more specifically, based on 100 g of the total monomer. may be added in an amount of 0.009 g to 4 g.

The polar additive may be a salt, ether, amine, or mixtures thereof, and specifically, tetrahydrofuran, ditetrahydrofurylpropane, diethyl ether, cycloamal ether, dipropyl ether, ethylene dimethyl ether, ethylene dimethyl ether, di Ethylene glycol, dimethyl ether, tertiary butoxyethoxyethane bis (3-dimethylaminoethyl) ether, (dimethylaminoethyl) ethyl ether, ethyl tetrafurfuryl ether, trimethylamine, triethylamine, tripropylamine and tetramethyl It may be at least one selected from the group consisting of ethylenediamine. More specifically, it may be ditetrahydrofurylpropane, ethyltetrafurfurylether, or tetramethylethylenediamine.

When the conjugated diene-based monomer and the aromatic vinyl-based monomer are copolymerized by using the polar additive, a random copolymer can be easily formed by compensating for a difference in their reaction rate.

The step (b) is a step of reacting the active polymer with the modifier represented by Formula 3 to prepare the modified copolymer.

The modifier represented by Chemical Formula 3 may be the same as described above, and may be one or a mixture of two or more used in the reaction.

The modifier represented by Formula 3 may be used in an amount of 0.1 mol or more to less than 2 mol relative to 1 mol of the organometallic compound. The modifier represented by Formula 3 may be used, for example, in an amount of 0.1 mol to 1.5 mol or less, preferably 0.2 mol to 0.5 mol per 1 mol of the organometallic compound. If the modifier is used in an amount that falls within the above ratio range, a coupling reaction with optimal performance may be performed, thereby obtaining the modified copolymer of the present invention.

The reaction of step (b) is a modification reaction for introducing a functional group into the copolymer, and may be performed at 0° C. to 90° C. for 1 minute to 5 hours.

In addition, the method for preparing the modified conjugated diene-based and aromatic vinyl-based copolymer may be performed by a batch method (batch type) or a continuous polymerization method including one or more reactive groups. The manufacturing method according to an embodiment of the present invention may further include one or more steps of recovering and drying the solvent and unreacted monomers as needed after the above step.

For example, the polymerization solvent, cyclohexane, can be used after passing through a tube filled with molecular sieve 5A and activated alumina and bubbling with high-purity nitrogen to sufficiently remove moisture, oxygen and other catalyst poisons. The monomer, styrene, can be used after passing through a tube filled with activated alumina to sufficiently remove polymerization inhibitor, moisture, oxygen, and the like.

All polymerizations can be carried out by adding an initiator after injecting a required amount of a solvent and each monomer to be polymerized in a high-pressure reactor (autoclave) completely blocked from external air.

In the viscoelastic characteristics of the conjugated diene-based and aromatic vinyl-based copolymers of the present invention, when measured at 10 Hz through DMA after silica mixing, the tan value at 60° C. is reduced, and rolling resistance or rotational resistance is improved This can lead to improved fuel economy performance.

According to another aspect of the present invention, there is provided a rubber composition comprising the modified conjugated diene-based and aromatic vinyl-based copolymer of the present invention and an inorganic filler. Through this, the molded article made of the rubber composition may have excellent fuel economy characteristics.

The rubber composition of the present invention may further include a filler in addition to the modified conjugated diene-based and aromatic vinyl-based copolymers. The modified conjugated diene-based and aromatic vinyl-based copolymers of the present invention have excellent affinity with fillers, so that the molded article obtained from the rubber composition of the present invention has excellent abrasion resistance, low rolling resistance, and high wet skid resistance, resulting in adjustment stability. can be excellent

The rubber composition of the present invention has a high tanδ measured at 0° C., and can have an effect of improving braking performance by improving wet resistance and roughing resistance, and improving fuel efficiency by improving rolling resistance and rolling resistance because tanδ measured at 60° C. is low It may work.

The filler may be included in an amount of 10 parts by weight to 200 parts by weight, preferably 50 parts by weight to 200 parts by weight, based on 100 parts by weight of the modified copolymer. Within the above range, the wear resistance may be excellent and there may be an effect of improving durability.

The filler may further include an organic filler commonly used in rubber compositions as well as inorganic fillers. For example, the organic filler may include one or more of carbon black and starch, and the inorganic filler may include one or more selected from the group consisting of silica, aluminum hydroxide, magnesium hydroxide, aluminum silicate and hydrated aluminum silicate. can Preferably, the filler may include silica, carbon black, or a combination thereof.

The rubber composition may further include a conjugated diene-based copolymer. The conjugated diene-based copolymer may include a homo-type copolymer of the above-described conjugated diene-based monomer. The conjugated diene-based copolymer is included in an amount of 10 parts by weight to 60 parts by weight, specifically 10 parts by weight to 50 parts by weight, more specifically 10 parts by weight to 30 parts by weight based on 100 parts by weight of the conjugated diene-based and aromatic vinyl-based copolymers. can Within the above range, there may be an effect of improving the physical properties of the rubber composition.

The rubber composition may further include an oil. The oils include vegetable oils such as paraffinic oil, aromatic oil, castor oil, mild extracted solvate (MES) oil, treated distillate aromatic extracted (TDAE) oil, low PCA oil including SRAE, heavy naphthenic oil, and black oil. It may include one or more types. The oil may be included in an amount of 1 part by weight to 100 parts by weight, specifically 10 parts by weight to 100 parts by weight, and more specifically 20 parts by weight to 80 parts by weight based on 100 parts by weight of the modified copolymer. Within the above range, the physical properties of the rubber composition may be well expressed and the rubber composition may be moderately softened to provide excellent processability.

The rubber composition may further include one or more additives commonly known to those skilled in the art in addition to fillers and oils, such as accelerators, waxes, fatty acids, processing aids, antioxidants, antioxidants, crosslinking agents, softeners, accelerators, and zinc oxide.

The additive may be included in an amount of 1 part by weight to 50 parts by weight, specifically 1 part by weight to 30 parts by weight, more specifically 1 part by weight to 10 parts by weight, based on 100 parts by weight of the modified conjugated diene-based and aromatic vinyl-based copolymer, respectively. . In the above range, it can serve as an additive without affecting the effectiveness of the rubber composition.

The rubber composition may be a vulcanized rubber composition further comprising sulfur. Sulfur is included in the rubber composition to form a network of rubber through a crosslinking reaction, thereby filling additives and improving durability. Sulfur may be included in an amount of 0.1 parts by weight to 50 parts by weight, specifically 0.1 parts by weight to 30 parts by weight, and more specifically 0.1 parts by weight to 10 parts by weight based on 100 parts by weight of the modified conjugated diene-based and aromatic vinyl-based copolymer. In the above range, the effect can be achieved without affecting the effect of the rubber composition.

Hereinafter, the molded article of this invention is demonstrated. According to another aspect of the present invention, there is provided a molded article prepared from the rubber composition of the present invention. The molded article may be a tire, tire tread, under-tread, sidewall, carcass coated rubber, belt coated rubber, bead filler, cheaper, or each member of the tire such as bead coated rubber, vibration proof rubber, belt conveyor, hose, etc. It may be various industrial rubber products. The molded article formed using the rubber composition may be a tire including a tire tread, and the molded article of the present invention exhibits excellent fuel efficiency characteristics.

The modified polymer of the present invention can impart improved processability in the uncured state of the rubber composition, and can significantly reduce the hysteresis in the crosslinked state and improve mechanical properties. Accordingly, the rubber composition of the present invention can be used in particular for the production of tires. In particular, the tire may be a tire tread.

Hereinafter, the present invention will be described in more detail through specific examples. The following examples are only examples to help the understanding of the present invention, and the scope of the present invention is not limited thereto.

Example

1. Preparation of modified copolymer

(1) Synthesis of denaturant

1) Synthesis of 4-methylcatechol acetonide

4-Methyl catechol (30.0 g, 241.5 mmol), 2,2-Dimethoxypropane (87.36 g, 102.9 mL, 840 mmol), para-toluenesulfonic acid mono Hydrate (p-Toluenesulfonic acid monohydrate) (0.4 g, 2.0 mmol) and benzene (Benzene) (262.2 g, 300 mL) were placed in a 1 L, two-necked round bottom flask to prepare a uniform solution. After installing the succilet extraction device, the reaction was conducted at a temperature of 120° C. for 8 hours. After removing all of the solvent, the remaining material was purified through distillation under reduced pressure at 65° C. and a pressure of 1x10 ^-3 mbar to synthesize 4-methylcatechol acetonide in a pale yellow liquid state. (yield = 89%)

2) Synthesis of 4-Bromomethylcatechol acetonide

4-Methyl catechol acetonide (20.0 g, 121.8 mmol), N-Bromosuccinimide (21.6 g, 121.2 mmol), 2,2'-azobisiso Butyronitrile (2,2'-Azobisiso butyronitrile) (0.8 g, 4.88 mmol) and cyclohexane (262.2 g, 300 mL) were placed in a 1 L, two-necked round-bottom flask. After mounting a reflux cooler, the reaction was carried out at a temperature of 100° C. for 6 hours. Thereafter, the precipitated succinimide was filtered to remove, and all solvents of the remaining liquid material were removed to synthesize 4-Bromomethyl catechol acetonide in a yellow liquid state. (yield = 98%)

¹ H NMR (400 MHz, CDCl ₃ ): δ (ppm) = 6.84 (dd, 1H, Ar-C5H, 7.8 Hz, 1.8 Hz), 6.81 (d, 1H, ArC3H, 1.8 Hz), 6.68 (d, 1H) , ArCH, 7.8 Hz), 4.48 (s, 2H, CH ₂ Br), 1.70 (s, 6H, C(CH ₃ ) ₂ ).

3) Synthesis of N-methyl-3-(triethoxysilyl)propyl-aminomethylcatechol acetonide (N-Methyl-3-(triethoxysilyl)propyl-aminomethylcatechol acetonide)

4-Bromomethyl catechol acetonide (4.88 g, 20.07 mmol), 3-Methyl Amino Propyl Trimethoxy-silane (3.88 g, 20.07 mmol) , Triethylamine (2.03 g, 20.07 mmol) and tetrahydrofuran (Tetrahydrofuran) (200 mL) were placed in a 500 mL, 1-necked round bottom flask and reacted at room temperature for 12 hours. The reaction solution was washed with a solvent in which water and methylene chloride were mixed in a ratio of 3:1, and then residual water was removed with magnesium sulfate. The solvent of the remaining liquid substance is removed through distillation, and the pale yellow liquid N-methyl-3-(triethoxysilyl)propyl-aminomethylcatechol acetonide, that is, N-(2,2-dimethylbenzo[d] [1,3]dioxol-5-yl)methyl)-N-methyl-3-(trimethoxysilyl)propan-1-amine (N-(2,2-dimethylbenzo[d][1,3]dioxol) -5-yl)methyl)-N-methyl-3-(trimethoxysilyl)propan-1-amine) was synthesized. (yield = 47%)

(2) Preparation of modified styrene-butadiene copolymer

Example 1: Modified styrene-butadiene copolymer using N-methyl-3-(triethoxysilyl)propyl-aminomethylcatechol acetonide

After replacing the inside of the autoclave reactor (internal capacity: 3 L, stainless steel) with nitrogen, 1,560 g of cyclohexane, 45.3 g of styrene, 178 g of 1,3-butadiene and 1.8 g of polar additive ethyl tetrafurfuryl ether were added. The reactor temperature was preheated to 50 °C, and 1.63 mmol of n-butyllithium was injected into the reactor, followed by an adiabatic temperature rise polymerization. After reacting for 30 minutes, 0.7 mmol of N-methyl-3-(triethoxysilyl)propyl-aminomethylcatechol acetonide (0.1 parts by weight based on 100 parts by weight of the total amount of styrene and 1,3-butadiene as a monomer mixture) was added. was added and reacted for 60 minutes. After that, ethanol was added to stop the reaction, the temperature was lowered to room temperature, and then 5 ml of a solution in which an antioxidant BHT (butylated hydroxytoluene) was dissolved in hexane by 0.3 wt% was added. Then, it was dried for 15 hours or more while heating to 80° C. in a vacuum oven to obtain a modified styrene-butadiene copolymer.

Comparative Example 1: Alkoxy silane-modified styrene-butadiene copolymer

Styrene-butadiene in the same manner as in Example 1 except that tetraethoxysilane (TEOS) was used instead of N-methyl-3-(triethoxysilyl)propyl-aminomethylcatechol acetonide in Example 1 A copolymer was obtained.

2. Confirmation of the physical properties of the copolymer

The physical properties of the copolymers prepared in Example 1 and Comparative Example 1 were confirmed as follows, and are shown in Table 1 below.

1) The content of vinyl and styrene contained in the copolymer is determined by taking a small amount of each copolymer obtained in Examples and Comparative Examples, re-dissolving them in a CDCl3 solvent for NMR, and then taking them in small portions to obtain 500MHz 1H NMR (device name: Avance ^DRX400 , manufacturer). : Bruker).

2) Weight average molecular weight (Mw, unit: g/mol) and molecular weight distribution (Mw/Mn, MwD) for each copolymer obtained in Examples and Comparative Examples, GPC (Gel Permeation Chromatography, Device Name: PL-GPC220, Manufacturer) : Agilent) analysis method.

3) The glass transition temperature was measured by a differential scanning calorimetry (Differential Scanning Calorimetry, device name: Q200, TA Instruments) analysis method.

4) Mooney viscosity was measured and analyzed using a Mooney viscometer (MV2000, Alpha Technology) after preheating at 100 °C for 1 minute and then measuring for 4 minutes.

5) Tan δ: Each copolymer obtained in Examples and Comparative Examples was put into an internal-type mixer with the composition shown in Table 2 below to prepare a formulation. The prepared formulation was compressed to obtain a specimen capable of measuring the tan δ of the formulation. For each of these specimens, tan δ at 60° C. was measured under conditions of 10 Hz and 0.2% strain using DMA (Dynamic Mechanical Analyzer, TA Instrument) as a temperature sweep test.

Example 1 Comparative Example 1 Styrene content (wt%) 21.1 21.0 Vinyl content (wt%) 65.0 62.0 Weight average molecular weight (Mw) 555,079 537,512 Molecular Weight Distribution (MwD) 1.13 1.07 )Tg (℃ -25.2 -25.7

Mooney Viscosity (ML1+4, 100

73.2 68.8

* Vinyl content (wt%): Vinyl weight / (butyene weight + vinyl weight) * 100

3. Preparation of tire tread composition and confirmation of physical properties

(1) Preparation of tire tread composition

A tire tread rubber composition was prepared by mixing and kneading the polymers obtained in each of the Examples and Comparative Examples in the composition shown in Table 2 below.

In more detail, the styrene-butadiene copolymer (SSBR) prepared in Example 1 and Comparative Example 1, respectively, prepared in Example 1 and Comparative Example 1, was added to a Banbari mixer, and silica, carbon black, anti-aging agent, softener, cross-linking aid, cross-linking agent as a compounding material A tire tread rubber composition was obtained by adding and blending in the same content as in Table 2 below, which are referred to as Experimental Example 1 and Comparative Experimental Example 1, respectively, and SSBR items in Table 2 below were prepared in Example 1 and Comparative Example 1 It means that the corresponding copolymer among the styrene-butadiene copolymers (SSBR) is added.

substance name content (phr; parts by weight) SSBR 80.0 Butadiene rubber 20.0 Silica (7000GR) 80.0 TDAE oil 37.5 ZnO 3.0 stearic acid 1.0 X50S coupling agent 12.8 Antioxidant 6PPD 2.0 Anti-aging agent RD (POLYMERIZED 2.2.4-TRIONETHYL-1.2-DIHYDROQUINOLINE) 1.0 Anti-aging agent WAX 2.0 Accelerator CZ (CBS) 1.7 Accelerator D (DPG) 2.0 Sulfur 1.9

(2) Checking the physical properties of the tire tread - loss factor

A tire tread sample was prepared using each tire tread composition obtained in 3.(1) above, and a tan delta value, which is a loss coefficient, was measured using each of them at a temperature of 60° C., and is shown in Table 3.

Experimental Example 1 Comparative Experimental Example 1 tan δ 60℃ 0.137 0.142 Mooney viscosity 53.4 60.3

Referring to Table 3, it was confirmed that the sample of Experimental Example 1 had a lower tan delta value, which is a loss coefficient at a temperature of 60°C, compared to the sample of Comparative Experimental Example 1, and that the loss coefficient was reduced as such. This means that silica and rubber are not easily separated due to dynamic deformation. As a result, the tire emits low energy during rotation, which reduces heat loss, thereby lowering rolling resistance and consequently improving fuel efficiency. can do.

Although the embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and variations are possible within the scope without departing from the technical spirit of the present invention described in the claims. It will be apparent to those of ordinary skill in the art.

Claims (8)

a repeating unit derived from a conjugated diene-based monomer; and
It is a copolymer comprising a repeating unit derived from an aromatic vinylic monomer,
The copolymer is a copolymer comprising at least one functional group represented by the following formula (1):

[Formula 1]
(In Formula 1,
R ¹ , R ² and R ⁵ are each independently selected from the group consisting of hydrogen, a hydroxy group, a hydroxy (C ₁ -C ₂₀ )alkyl group, and a straight-chain and branched (C ₁ -C ₂₀ )alkyl group,
R ³ and R ⁴ are each independently selected from the group consisting of N, S, O and Si;
R ⁶ and R ⁷ are each independently selected from the group consisting of hydrogen, a straight-chain and branched (C ₁ -C ₂₀ )alkyl group,
R ⁸ may be selected from the group consisting of straight-chain and branched (C ₁ -C ₂₀ )alkylene groups, or may form a single bond or a divalent linking group between N and Si; and
R ⁹ and R ¹⁰ are each independently selected from the group consisting of straight-chain and branched (C ₁ -C ₅ )alkyl groups).
The copolymer according to claim 1, wherein the functional group of Formula 1 is represented by Formula 2:

[Formula 2]
R ¹ , R ² and R ⁵ are hydrogen;
R ³ and R ⁴ are O;
R ⁶ , R ⁷ , R ⁹ and R ¹⁰ are each independently selected from the group consisting of a straight-chain (C ₁ -C ₅ )alkyl group;
R ⁸ is a single bond between N and Si or a hydrocarbon group of -(CH ₂ ) _l -, wherein l is an integer of 1 to 10; and
M ¹ and M ² are each independently a conjugated diene-based copolymer and an aromatic vinyl-based copolymer.
(a) preparing an active polymer by polymerizing an aromatic vinyl-based monomer and a conjugated diene-based monomer in a hydrocarbon solvent in the presence of an organic alkali metal compound; and
(b) a method for preparing a copolymer comprising the step of reacting the active polymer with a modifier of formula (3):

[Formula 3]
(In Formula 3,
R ¹ , R ² and R ⁵ are each independently selected from the group consisting of hydrogen, a hydroxyl group, a hydroxy (C ₁ -C ₂₀ )alkyl group, and a straight-chain and branched (C ₁ -C ₂₀ )alkyl group,
R ³ and R ⁴ are each independently selected from the group consisting of N, S, O and Si;
R ⁶ , R ⁷ , R ¹¹ and R ¹² are each independently selected from the group consisting of hydrogen, straight-chain and branched (C ₁ -C ₂₀ )alkyl groups,
R ⁸ may be selected from the group consisting of straight-chain and branched (C ₁ -C ₂₀ )alkylene groups, or may form a single bond or a divalent linking group between N and Si; and
R ⁹ and R ¹⁰ are each independently selected from the group consisting of straight-chain and branched (C ₁ -C ₅ )alkyl groups).
The method according to claim 3, wherein Chemical Formula 3 is
R ¹ , R ² and R ⁵ are hydrogen;
R ³ and R ⁴ are O;
R ⁶ , R ⁷ , R ⁹ , R ¹⁰ , R ¹¹ and R ¹² are each independently selected from the group consisting of straight-chain and branched (C ₁ -C ₅ )alkyl groups; and
R ⁸ is a single bond between N and Si or -(CH ₂ ) _l - a hydrocarbon group, wherein l is an integer of 1 to 10, a method for producing a copolymer.
A rubber composition comprising the copolymer of claim 1 or 2 and an inorganic filler.
The rubber composition according to claim 5, wherein the inorganic filler is at least one selected from the group consisting of silica, aluminum hydroxide, magnesium hydroxide, aluminum silicate and hydrated aluminum silicate.
A molded article prepared from the rubber composition of claim 5 .
8. The molded article according to claim 7, wherein the molded article is a tire comprising a tire tread.