KR100449367B1 - End modified diene copolymer and its rubber composition for tire tread - Google Patents

Abstract

The present invention relates to a terminal-modified diene copolymer and a rubber composition for a tire tread comprising the same, wherein the homopolymer or at least one conjugated diene compound and vinyl substitution of a conjugated diene compound polymerized with an organolithium initiator in the presence of a nonpolar solvent. Terminal-modified diene-based copolymer obtained by coupling the activated terminal of the copolymer consisting of an aromatic compound to at least one compound selected from organosilicon compounds including polyalkylene groups represented by the following formula (1), and including it as raw material rubber In addition to the mechanical properties, the tires have improved rolling resistance values and wet slip resistance values.

(X) _a (R) _b (R ¹ ) _c Si-R ³ (R ⁴ ) _d (R ⁵ ) _e -Si (X) _f (R) _g (R ² ) _h

Wherein X is at least one selected from halogen atoms such as fluorine, chlorine, bromine or iodine; R ¹ and R ² are an alkyl group having 1 to 10 carbon atoms or hydrogen which is unsubstituted or substituted with fluorine or chlorine; R ³ is alkylene having 1 to 10 carbon atoms; R ⁴ and R ⁵ are the same as or different from each other and are hydrogen, Si (X) _a (R) _b (R ¹ ) _c or Si (X) _f (R) _g (R ² ) _h ; R is a polyalkylene group having the general formula C (R ⁶ ) (R ⁷ ) CH (R ⁸ ) C (R ⁶ ) (R ⁷ ) O- {C (R ⁶ ) (R ⁷ ) C (R ⁶ ) ( R ⁷ ) O} _i R ⁹ , wherein R ⁶ , R ⁷ and R ⁸ are the same as or different from each other, an alkyl group having 1 to 10 carbon atoms, unsubstituted or substituted with chlorine or fluorine, hydrogen, fluorine or chlorine, and R ⁹ is methyl, ethyl, C (= 0) (CH ₂ ) _h CH ₃ or SO ₂ CH ₃ ; a and f are numbers between 1 and 3; d and e are 0 or 1; b, c, g and h are numbers between 0 and 2, provided that a + b + c + f + g + h = 6; i is a number between 0 and 20.

Description

END modified diene copolymer and its rubber composition for tire tread}

The present invention relates to a terminally modified diene copolymer and a rubber composition for tire treads comprising the same, more particularly homopolymer or at least one conjugated diene of a conjugated diene-based compound polymerized with an organolithium initiator in the presence of a nonpolar solvent. Terminal-modified diene copolymer obtained by coupling an activated terminal of a copolymer composed of a compound with a vinyl substituted aromatic compound to at least one compound selected from organosilicon compounds including polyalkylene groups represented by the following formula (1) The present invention relates to a rubber tread composition comprising a rubber as a raw material.

Looking at the recent trends in the automotive industry, there are compelling economic considerations in terms of saving natural resources and saving energy. In addition, there is a constant need for durability, stability and fuel savings, and efforts are being made to meet that demand.

Thus, one of the goals for developing automotive tire technology today is to lower the rolling resistance value, which is directly related to fuel savings.

When the rubber of a tire in motion is regularly deformed in a relatively low frequency band, the energy is dispersed and the rolling resistance of the car tire is formed. This resistance can be reduced by reducing the energy loss that occurs during operation.

In other words, based on the temperature conversion formula Williams-Landel-Ferry equation, the frequency is converted into a function of temperature and then the dynamic loss factor (tan δ, an exponent of the loss content for energy loss) between 50 and 70 ° C is measured. This value is a measure of rolling resistance.

On the other hand, efforts are being made to increase wet skid resistance in order to improve the braking performance of tires on the surface of the rain which is directly related to stability. The car tires slide on the surface of the road at the same time the driver brakes. At this time, the tread portion of the tire directly in contact with the road surface of the road suffers a lot of energy loss due to the frictional resistance. Since the wet slip resistance is formed by the tire movement of a relatively high frequency band compared to the frequency band at which rolling resistance is formed, the dynamic loss factor value near 0 ° C is a measure of this performance.

As such, in order to satisfy the two important properties of the above-mentioned tires, styrene-butadiene rubber by emulsion polymerization method, butadiene rubber with high cis content, butadiene rubber with low cis content, and styrene polymerized using organic lithium as catalysts Butadiene rubber, natural rubber, and isoprene rubber with high cis content have been used alone or in combination as raw materials. However, these rubbers proved inadequate to satisfy both of the above properties.

In particular, to obtain low rolling resistance values, it is necessary to increase the content of low-ciss butadiene rubber or natural rubber which shows low wet resistance, reduce the amount of filler such as carbon black, or increase the amount of crosslinking agent such as sulfur. do.

However, these methods are effective in lowering the wet slip resistance value of the tire, but have the disadvantage of degrading the mechanical properties.

On the other hand, in order to obtain a high wet slip resistance value, styrene-butadiene rubber having a high styrene content (for example, having a styrene content of about 30% by weight) or butadiene rubber having a high vinyl content (for example, having a vinyl content of 60% by weight Increase the amount of filler, such as carbon black or oil. However, this method also has the drawback of increasing the rolling resistance value.

In order to improve these properties, Japanese Patent Application Laid-Open No. 57-87407 and Japanese Patent Application Laid-open 58-162605 use organic lithium as an initiator, and the active end of the styrene-butadiene copolymer having high vinyl content is determined by tin tetrachloride (SnCl). ₍₄ ) proposed a method of improving the running resistance along with the workability when the rubber for the tire tread was blended by coupling to.

However, tires improved by this method also did not have sufficient wet slip resistance.

In addition, US Patent No. 3,281,383 and Japanese Patent Laid-Open No. 54-15994 suggest a method of reacting a halogenated silicon compound such as silicon tetrachloride with the living end of the polymer. However, the polymer produced by this method has excellent mechanical strength and abrasion resistance, but is poor in workability, and the wet slip resistance is also lowered.

In addition, U.S. Patent No. 3,078,254 used a multi-halogen substituted hydrocarbon such as 1,3,5-tri (bromomethyl) benzene as a coupling agent, but in this case, the coupling efficiency is low and the molecular weight is not uniform. This has the problem of falling.

In addition, Korean Patent Publication No. 90-6274 discloses a balance between wet slip resistance, tensile strength, repulsive elasticity, and exothermicity by terminating a polymer by reacting conjugated diene or styrene with carbodiimide at the active end of the copolymer. There was an improvement.

In addition, as a similar technique, Korean Patent Publication No. 90-8331 has an example in which the performance of a tire is improved by modifying the active terminal of the polymer with a polyfunctional compound containing a diglycidyl amino group.

However, the above examples are inadequate to be used in tires that can satisfy all of the driving characteristics, wet slip resistance, and abrasion resistance, etc. of the industry that require all-weather tires in recent years. It is a required situation.

Accordingly, the present inventors have been researching to solve the problems of the rubber for the tire tread, and a homopolymer of a conjugated diene-based compound polymerized with an organolithium initiator in the presence of a nonpolar solvent, or one or more conjugated diene compounds and vinyl substituted aromatic compounds. The modified terminal is modified by coupling the activated terminal of the copolymer to at least one compound selected from organosilicon compounds including polyalkylene groups, thereby simultaneously improving not only the mechanical properties of the tire but also the rolling resistance and the wet slip resistance. It was found that the present invention can be completed.

Accordingly, it is an object of the present invention to provide a terminally modified diene-based copolymer capable of simultaneously improving the rolling resistance value and the wet sliding resistance value as well as the improvement of mechanical properties directly related to the tire physical properties.

In addition, another object of the present invention to provide a rubber tread composition for a tire tread comprising the terminal-modified diene copolymer prepared above.

The terminal-modified diene copolymer of the present invention for achieving the above object is a homopolymer of a conjugated diene-based compound polymerized with an organolithium initiator in the presence of a nonpolar solvent or an air composed of at least one conjugated diene compound and a vinyl substituted aromatic compound. It is characterized in that it is obtained by coupling the activated end of the copolymer to at least one compound selected from organosilicon compounds including polyalkylene groups represented by the following formula (1).

Formula 1

(X) _a (R) _b (R ¹ ) _c Si-R ³ (R ⁴ ) _d (R ⁵ ) _e -Si (X) _f (R) _g (R ² ) _h

Wherein X is at least one selected from halogen atoms such as fluorine, chlorine, bromine or iodine; R ¹ and R ² are an alkyl group having 1 to 10 carbon atoms or hydrogen which is unsubstituted or substituted with fluorine or chlorine; R ³ is alkylene having 1 to 10 carbon atoms; R ⁴ and R ⁵ are the same as or different from each other and are hydrogen, Si (X) _a (R) _b (R ¹ ) _c or Si (X) _f (R) _g (R ² ) _h ; R is a polyalkylene group having the general formula C (R ⁶ ) (R ⁷ ) CH (R ⁸ ) C (R ⁶ ) (R ⁷ ) O— {C (R ⁶ ) (R ⁷ ) C (R ⁶ ) ( R ⁷ ) O} _i R ⁹ , wherein R ⁶ , R ⁷ and R ⁸ are the same as or different from each other, an alkyl group having 1 to 10 carbon atoms, unsubstituted or substituted with chlorine or fluorine, hydrogen, fluorine or chlorine, and R ⁹ is methyl, ethyl, C (= 0) (CH ₂ ) _h CH ₃ or SO ₂ CH ₃ ; a and f are numbers between 1 and 3; d and e are 0 or 1; b, c, g and h are numbers between 0 and 2, provided that a + b + c + f + g + h = 6; i is a number between 0 and 20.

In addition, 100 parts by weight of the raw material rubber containing at least 10% by weight of the terminally modified conjugated diene-based copolymer obtained; 10 to 100 parts by weight of an inorganic filler; The rubber composition for tire treads which contains 0.1-5 weight part of sulfur and other additives has the characteristics.

The present invention will be described in more detail as follows.

The present invention relates to a polyalkylene represented by the following formula (1), wherein the activated terminal of a homopolymer of a conjugated diene-based compound polymerized with an organic lithium initiator in the presence of a nonpolar solvent or a copolymer of at least one conjugated diene compound and a vinyl substituted aromatic compound The present invention relates to a terminal-modified diene copolymer obtained by coupling with at least one compound selected from organosilicon compounds including a group, and a rubber composition for tire tread composed of raw rubber, reinforcing agent, sulfur, and other additives including the same.

The conjugated diene-based copolymer used in the present invention is a polymerization start with an organic lithium initiator, wherein the conjugated diene-based compound uses isoprene or 1,3-butadiene.

In addition, examples of the organolithium initiator which can be used as a polymerization initiator of the conjugated diene copolymer are hydrocarbon-based compounds bonded with at least one lithium atom, and specific examples thereof include ethyl lithium, propyl lithium, n-butyl lithium and sec-butyl. Lithium, tert-butyl lithium, phenyl lithium, propenyl lithium, hexyl lithium, 1,4-dirithio-n-butane, 1,3-di (2-lithio-2-hexyl) benzene, and the like. Is n-butyl lithium, sec-butyl lithium, and the like.

Such an organic lithium initiator may be used in one kind or in a mixture of two or more kinds. The amount of the organolithium catalyst used may vary depending on the target molecular weight of the produced polymer, but is usually 0.1 to 5 millimoles per 100 g of monomer, preferably 0.3 to 4 mmol.

The polymerization solvent used in the present invention is a hydrocarbon solvent such as n-butane, iso-pentane, n-hexane, n-heptane, iso-octane, cyclohexane, methylcyclopentane, benzene, toluene, and the like. -Hexane, n-heptane, cyclohexane and the like. Usually, the usage-amount of a polymerization solvent is used in the quantity of 1-20 weight part per 1 weight part of monomers.

The conjugated diene polymer of the present invention may be a polymer of not only a conjugated diene compound but also a copolymer of at least one conjugated diene compound and a vinyl substituted aromatic compound.

At this time, the vinyl-substituted aromatic compound is selected from styrene and α-methyl styrene.

In the copolymer of the conjugated diene compound and the vinyl substituted aromatic compound, the content of the vinyl substituted aromatic compound is in the range of 10 to 50%. If the vinyl-substituted aromatic compound is less than 10%, the glass transition temperature is lowered, so that the wet friction, which is one of the rubber properties, is lowered, and if the vinyl substituted aromatic compound is more than 50%, it loses the rubber properties and has the properties of plastics.

Also in the conjugated diene-based copolymer, the vinyl content of the conjugated diene portion contains an amount between 20 and 90 mol%.

If the vinyl content is less than 20 mol%, the glass transition temperature is lowered and the physical properties are lowered. If the vinyl content is more than 90 mol%, the low temperature property of the rubber becomes a problem because the glass transition temperature is high.

As a result of measuring the molecular weight of the obtained conjugated diene copolymer by gel permeation chromatography (GPC), the number average molecular weight (Mn) before coupling has a value of 10,000-300,000.

On the other hand, the terminal-modified conjugate by coupling the active terminal of the homopolymer of the conjugated diene compound or the copolymer with the vinyl-substituted aromatic compound polymerized using the organolithium initiator as described above to the organosilicon compound represented by the following formula (1) A diene copolymer is prepared.

Formula 1

(X) _a (R) _b (R ¹ ) _c Si-R ³ (R ⁴ ) _d (R ⁵ ) _e -Si (X) _f (R) _g (R ² ) _h

Wherein X is at least one selected from halogen atoms such as fluorine, chlorine, bromine or iodine; R ¹ and R ² are an alkyl group having 1 to 10 carbon atoms or hydrogen which is unsubstituted or substituted with fluorine or chlorine; R ³ is alkylene having 1 to 10 carbon atoms; R ⁴ and R ⁵ are the same as or different from each other and are hydrogen, Si (X) _a (R) _b (R ¹ ) _c or Si (X) _f (R) _g (R ² ) _h ; R is a polyalkylene group having the general formula C (R ⁶ ) (R ⁷ ) CH (R ⁸ ) C (R ⁶ ) (R ⁷ ) O— {C (R ⁶ ) (R ⁷ ) C (R ⁶ ) ( R ⁷ ) O} _i R ⁹ , wherein R ⁶ , R ⁷ and R ⁸ are the same as or different from each other, an alkyl group having 1 to 10 carbon atoms, unsubstituted or substituted with chlorine or fluorine, hydrogen, fluorine or chlorine, and R ⁹ is methyl, ethyl, C (= 0) (CH ₂ ) _h CH ₃ or SO ₂ CH ₃ ; a and f are numbers between 1 and 3; d and e are 0 or 1; b, c, g and h are numbers between 0 and 2, provided that a + b + c + f + g + h = 6; i is a number between 0 and 20.

In addition, the compound represented by Chemical Formula 1 uses 0.1 mol to 0.3 mol with respect to 1 mol of the organolithium initiator, and if the amount thereof is less than 0.1 mol, the amount of the terminally modified copolymer is not sufficient so that the effect of terminal modification is not sufficient. In addition, when it exceeds 0.3 mol, the amount of the terminally modified copolymer is too large to cause a problem in workability.

Thus, the pattern viscosity (ML _{1 + 4} , 100 degreeC) of the terminal modified | denatured conjugated diene copolymer obtained after coupling generally has a value of 30 or more normally.

In addition, the number average molecular weight of the conjugated diene copolymer modified | denatured using the organosilicon compound containing the atom group group represented by General formula (1) shows the value of 20,000-1,500,000.

On the other hand, the present invention also relates to the application to the rubber composition for tire tread containing the raw rubber, inorganic filler, sulfur and other additives comprising the terminally modified diene copolymer obtained above, when used as such raw rubber It can be used alone or mixed with other rubbers which have been used previously.

The terminally modified diene-based copolymer in the raw material rubber is mixed with the terminally-modified diene-based copolymer so as to be 10 to 90% by weight or more, preferably 20% by weight or more, and when the content is less than 10% by weight, the rolling resistance is improved. It is not expected to improve the wet slip resistance and the like, and when it exceeds 90% by weight, the economical efficiency is lowered due to the expensive modified diene polymer.

On the other hand, the inorganic filler used in the present invention is one or more selected from granulated precipitated silica, alumina, aluminosilicate and carbon black, and preferably silica and carbon black.

The inorganic filler of the present invention is contained in 10 to 100 parts by weight based on 100 parts by weight of the diene rubber. If the content is less than 10 parts by weight, there is no reinforcing effect on the rubber, so that the mechanical properties of the rubber composition are not improved. If the content is more than 100 parts by weight, the miscibility with the rubber is lowered, so that the uniform compounding property is hard to appear. .

In addition, when silica is used in the reinforcing agent, the bis-3-triethoxysilyl-propyl-tetrasulfide is further included as a coupling agent in an amount of 0.1 to 10 parts by weight based on 100 parts by weight of the silica. If the content is less than 0.1 parts by weight, the effect of the coupling agent is insignificant, which does not help to improve the physical properties. If the content is more than 10 parts by weight, the expensive coupling agent is uneconomical because it affects the unit price of the final product. .

In addition, sulfur is contained in 0.1 to 5 parts by weight with respect to 100 parts by weight of the diene rubber, if the content is less than 0.1 parts by weight can not be expected crosslinking effect can not improve the mechanical properties, if it exceeds 5 parts by weight The elasticity of the crosslinked product is lost, and properties as a rubber cannot be expected.

In addition, of course, other rubber compounding agents used in combination with the conventional tire tread rubber composition may be added.

The characteristics of the rubber composition for tire treads based on the rubber thus obtained were improved by reducing the rolling resistance value without loss of the wet sliding resistance, and other values such as the tensile strength value while appropriately matching the rolling resistance and the wet sliding resistance value. Mechanical properties are also improved.

Hereinafter, the present invention will be described in detail with reference to the following Examples, but the present invention is not limited thereto.

Preparation Example 1 Preparation of SBR 1 and SBR 2

The 10 L stainless steel polymerization reactor was washed with cyclohexane solvent and dried to reflux with nitrogen, followed by 670 g of 1,3-butadiene, 225 g of styrene monomer, 5400 g of cyclohexane solvent, and tetrahydrofuran (THF) 27 g And 3.8 mmol of n-butyllithium (0.5 molar cyclohexane solution) were injected into the reaction vessel.

The polymerization was started at 35 ° C. and the contents were then stirred for 1 hour. Since the polymerization reaction in the adiabatic polymerization reactor was exothermic, when the reaction temperature reached a peak value, 5 g of 1,3-butadiene was further added and the reaction was further proceeded for 20 minutes. Then, 0.38 mmol of the organosilicon compound coupling agent represented by the following Formula 2 was injected and further stirred for about 30 minutes, and then the reaction was stopped by injecting an excessive amount of BHT solution dissolved in cyclohexane into the polymer solution.

Acetone was added to the reacted polymer to precipitate the polymer, and the resulting solid was dried under reduced pressure at 60 ° C. for 24 hours to obtain a terminally modified styrene-butadiene copolymer SBR 1 having a functional group introduced at the polymer end.

Meanwhile, SBR 2 was prepared in the same manner using 178 g of THF.

The number value molecular weight, the number of coupling (CN) and the coupling efficiency (CE) of the obtained rubber were measured using a pattern viscometer and gel permeation chromatography (GPC), and the results are shown in Table 1 below. .

In addition, the bound styrene content and the vinyl content of butadiene in the terminally modified styrene-butadiene copolymer were measured using a ¹ H-NMR instrument, and the results are shown in Table 1 below.

Preparation Example 2 Preparation of SBR 3 and SBR 4

As in Synthesis Example 1, a 10 L stainless steel polymerization reactor was washed and dried to reflux with dry nitrogen, followed by 706 g of 1,3-butadiene, 189 g of styrene, 5400 g of cyclohexane solvent, tetrahydrofuran (THF) 27 g, and n Inject 4.8 mmol of butyllithium (0.5 mol cyclohexane solution) into the reaction vessel.

The polymerization was started at 37 ° C. and the contents were then stirred for 1 hour. Since the polymerization reaction in the adiabatic polymerization reactor was exothermic, when the reaction temperature reached a peak value, 5 g of 1,3-butadiene was further added and the reaction was further proceeded for 20 minutes. Then, 0.48 mmol of the organosilicon compound coupling agent represented by the following formula (3) was injected and further stirred for about 30 minutes, and then the reaction was stopped by injecting an excessive amount of BHT solution dissolved in cyclohexane into the polymer solution.

Acetone was added to the reacted polymer to precipitate the polymer, and the resulting solid was dried under reduced pressure at 60 ° C. for 24 hours to obtain styrene-butadiene copolymer 3 having a functional group introduced at the polymer end.

Meanwhile, SBR 4 was prepared in the same manner using 216 g of THF.

The rubber pattern, number average molecular weight, coupling number (CN) and coupling efficiency (CE) of the obtained rubber, as well as the bound styrene content and the vinyl content of butadiene in the terminally modified styrene-butadiene copolymer, were obtained in the same manner as in Synthesis Example 1. It was measured, and the results are shown in Table 1 below.

Comparative Production Example 1 Preparation of SBR 5 and SBR 6

The reaction was conducted under the same conditions and reactants as in Synthesis Example 1, except that tin tetrachloride (SnCl ₄ ) was added as a coupling agent in an amount of 0.5 molar equivalents to the polymerization initiator, and a styrene-butadiene air having a functional group introduced to the polymer terminal. Unions 5 (hereinafter referred to as SBR 5) and 6 (hereinafter referred to as SBR 6) were obtained.

The rubber pattern, number average molecular weight, coupling number (CN) and coupling efficiency (CE) of the obtained rubber, as well as the bound styrene content and the vinyl content of butadiene in the terminally modified styrene-butadiene copolymer, were obtained in the same manner as in Synthesis Example 1. It was measured, and the results are shown in Table 1 below.

Comparative Production Example 2 Preparation of SBR 7 and SBR 8

The reaction was carried out under the same conditions and reactants as in Synthesis Example 1, except that silicon tetrachloride (SiCl ₄ ) was added as a coupling agent in an amount of 0.5 molar equivalent to the polymerization initiator, and styrene-butadiene introduced with a functional group at the polymer terminal. Copolymers 7 (hereinafter referred to as SBR 7) and 8 (hereinafter referred to as SBR 8) were obtained.

The rubber pattern, number average molecular weight, coupling number (CN) and coupling efficiency (CE) of the obtained rubber, as well as the bound styrene content and the vinyl content of butadiene in the terminally modified styrene-butadiene copolymer, were obtained in the same manner as in Synthesis Example 1. It was measured, and the results are shown in Table 1 below.

Comparative Production Example 3 Preparation of SBR 9 and SBR 10

After the polymerization was carried out in the same manner as in Synthesis Example 2, 1 mmol of SnCl ₄ was added to 4.8 mmol of the catalyst instead of the polysiloxane compound of Synthesis Example 2. Then, compounds 9 (hereinafter referred to as SBR 9) and 10 (hereinafter referred to as SBR 10) obtained by stopping the reaction by injecting a solution of BHT (cyclohexane solvent) were compared.

The rubber pattern, number average molecular weight, coupling number (CN) and coupling efficiency (CE) of the obtained rubber, as well as the bound styrene content and the vinyl content of butadiene in the terminally modified styrene-butadiene copolymer, were obtained in the same manner as in Synthesis Example 1. It was measured, and the results are shown in Table 1 below.

Comparative Production Example 4 Preparation of SBR 11 and SBR 12

After the polymerization was carried out in the same manner as in Synthesis Example 2, 1 mmol of SnCl ₄ was added to 4.8 mmol of the catalyst instead of the polysiloxane compound of Synthesis Example 2. Then, compounds 11 (hereinafter referred to as SBR 11) and 12 (hereinafter referred to as SBR 12) obtained by injecting a BHT (cyclohexane solvent) solution to stop the reaction were compared.

The rubber pattern, number average molecular weight, coupling number (CN) and coupling efficiency (CE) of the obtained rubber, as well as the bound styrene content and the vinyl content of butadiene in the terminally modified styrene-butadiene copolymer, were obtained in the same manner as in Synthesis Example 1. It was measured, and the results are shown in Table 1 below.

Pattern value ML _{1 + 4} (100 ℃) Number average molecular weight Coupling Number (CN) Coupling Efficiency (CE) Styrene Content (wt%) Vinyl content of butadiene (mol%) Before Coupling After coupling Preparation Example 1 SBR 1 128 240,000 960,000 4 40 25 40 SBR 2 120 230,000 920,000 4 40 25 60 Preparation Example 2 SBR 3 130 190,000 900,000 4.7 50 21 40 SBR 4 125 185,000 880,000 4.8 50 21 60 Comparative Production Example 1 SBR 5 128 240000 800000 3.3 50 25 40 SBR 6 121 230,000 800,000 3.4 50 25 60 Comparative Production Example 2 SBR 7 128 240,000 800,000 3.3 50 25 40 SBR 8 121 235,000 810,000 3.4 50 25 60 Comparative Production Example 3 SBR 9 128 210,000 735,000 3.5 50 21 40 SBR 10 124 215,000 753,000 3.5 50 21 60 Comparative Production Example 4 SBR 11 128 210,000 730,000 3.5 50 21 40 SBR 12 125 210,000 740,000 3.5 50 21 60

Examples 1-2 and Comparative Examples 1-4

The terminal-modified styrene-butadiene copolymer SBR 1,2,3,4 obtained in each of the above preparations with the composition of Table 2 and the terminally modified styrene-butadiene copolymer SBR 4,5,6, obtained in the comparative preparations A rubber composition was prepared by applying the same to 7,8,9,10,11,12.

The manufacturing method was made of the respective rubber composition after mixing the rubber before mixing using a mixer of 250ml Brabender type. Sulfur and vulcanization accelerators were used in an amount sufficient to achieve optimum conditions for the rubber composition. Each rubber composition was vulcanized at 145 ° C. for 10-30 minutes, thereby producing a final test sample.

The physical properties after vulcanization of the samples prepared through the vulcanization process were measured. The properties of strength were measured according to JIS K-6301. The characteristics of rolling resistance and wet slip resistance were measured by dynamic mechanical analyzer (DMA), and the rolling resistance was measured at 60 ° C and wet slip resistance at 0 ° C, respectively.

Furtherance Parts by weight SBR polymer 100 Paraffin oil 37.5 Silica 60 Coupling agent 4.8 Zinc oxide 3 Stearic acid 2 Antioxidant One sulfur 1.5 Vulcanization accelerator 3.3

Rubber composition Tensile Strength (kg / cm ² ) Elongation (%) Wet Slip Resistance (tan δat 0 ^o C) Rolling resistance (tan δat 60 ^o C) Example 1 SBR 1 221 610 0.440 0.075 SBR 2 224 600 0.450 0.079 Example 2 SBR 3 211 620 0.380 0.101 SBR 4 200 630 0.391 0.109 Comparative Example 1 SBR 5 180 627 0.292 0.091 SBR 6 179 620 0.315 0.097 Comparative Example 2 SBR 7 201 621 0.350 0.085 SBR 8 198 617 0.362 0.084 Comparative Example 3 SBR 9 180 610 0.310 0.122 SBR 10 175 615 0.312 0.127 Comparative Example 4 SBR 11 190 617 0.353 0.119 SBR 12 186 621 0.361 0.111

It can be seen from the results of Table 3 that the rubber composition of the present invention has improved tensile strength, frictional resistance, wet sliding resistance and rolling resistance values than the comparative example. In particular, the improvement in the wet slip resistance and rolling resistance portions is noticeable.

As described in detail above, a copolymer obtained by end-modifying an active end of a copolymer of a conjugated diene compound and a vinyl substituted aromatic compound polymerized in a hydrocarbon solvent using an organic polymerization catalyst with an organosilicon compound coupling agent and the same Rubber treads for tire treads have dramatically improved mechanical properties such as tensile strength, especially high wet slip resistance, which indicates the braking performance of tires on rain surfaces directly related to stability, and rolling resistance directly related to fuel savings. It is an economical and simple process that can have excellent effects such as low value and exhibit excellent physical properties by addition of an organosilicon compound, and thus is a method that can be particularly useful industrially.

Claims (9)

The activated terminal of a homopolymer of a conjugated diene-based compound polymerized with an organic lithium initiator in the presence of a nonpolar solvent or a copolymer of at least one conjugated diene compound and a vinyl substituted aromatic compound includes a polyalkylene group represented by the following formula (1) A terminally modified diene copolymer obtained by coupling with at least one compound selected from organosilicon compounds. Formula 1 (X) _a (R) _b (R ¹ ) _c Si-R ³ (R ⁴ ) _d (R ⁵ ) _e -Si (X) _f (R) _g (R ² ) _h Wherein X is at least one selected from halogen atoms such as fluorine, chlorine, bromine or iodine; R ¹ and R ² are an alkyl group having 1 to 10 carbon atoms or hydrogen which is unsubstituted or substituted with fluorine or chlorine; R ³ is alkylene having 1 to 10 carbon atoms; R ⁴ and R ⁵ are the same as or different from each other and are hydrogen, Si (X) _a (R) _b (R ¹ ) _c or Si (X) _f (R) _g (R ² ) _h ; R is a polyalkylene group having the general formula C (R ⁶ ) (R ⁷ ) CH (R ⁸ ) C (R ⁶ ) (R ⁷ ) O— {C (R ⁶ ) (R ⁷ ) C (R ⁶ ) ( R ⁷ ) O} _i R ⁹ , wherein R ⁶ , R ⁷ and R ⁸ are the same as or different from each other, an alkyl group having 1 to 10 carbon atoms, unsubstituted or substituted with chlorine or fluorine, hydrogen, fluorine or chlorine, and R ⁹ is methyl, ethyl, C (= 0) (CH ₂ ) _h CH ₃ or SO ₂ CH ₃ ; a and f are numbers between 1 and 3; d and e are 0 or 1; b, c, g and h are numbers between 0 and 2, provided that a + b + c + f + g + h = 6; i is a number between 0 and 20. The terminal-modified diene-based copolymer according to claim 1, wherein the compound represented by Chemical Formula 1 uses 0.1 to 0.3 moles with respect to 1 mole of the organolithium initiator. The method of claim 1, wherein the organic lithium initiator is at least one selected from the group consisting of ethyl lithium, propyl lithium, n-butyl lithium, sec-butyl lithium, tert- butyl lithium, phenyl lithium and propenyl lithium. Terminally modified diene copolymer. The terminal-modified diene copolymer according to claim 1, wherein the content of the vinyl-substituted aromatic compound of the copolymer comprising at least one conjugated diene compound and a vinyl substituted aromatic compound is 10 to 50%. The number average molecular weight of the homopolymer or copolymer of the conjugated diene-based compound according to claim 1, wherein the number average molecular weight (Mn) before coupling is 10,000 to 300,000, and the number-average molecular weight of the conjugated diene-based copolymer after the end-modification is coupled. Silver-modified diene copolymer characterized in that the range of 20,000 to 1,500,000. The terminally modified diene-based copolymer according to claim 1, wherein the conjugated diene-based compound is selected from isoprene and 1,3-butadiene, and the vinyl-substituted aromatic compound is selected from styrene and α-methyl styrene. The terminally modified diene copolymer according to claim 1, wherein the terminally modified diene copolymer has 20 to 90 mol% of vinyl bonds in the butadiene moiety. A rubber composition for tire treads, comprising 100 parts by weight of raw material rubber, 10 to 100 parts by weight of inorganic filler, 0.1 to 5 parts by weight of sulfur, and other additives, including at least 10% by weight or more of the terminally modified diene copolymer. The rubber composition for tire treads according to claim 8, wherein the inorganic filler is silica or carbon black.