KR102056457B1 - A rubber composition for tire tread comprising low-cis polybutadiene - Google Patents

Abstract

One aspect of the present invention, the content of the cis-1,4 bond is 10 to 50% by weight and 30 to 80% by weight of polybutadiene having a glass transition temperature of -100 to 50 ° C; And 20 to 70% by weight of the copolymer consisting of an aromatic vinyl monomer and a conjugated diene monomer; provides a tire tread rubber composition comprising a.

Description

A tire tread rubber composition containing the curse polybutadiene {A RUBBER COMPOSITION FOR TIRE TREAD COMPRISING LOW-CIS POLYBUTADIENE}

The present invention relates to a tire tread rubber composition comprising low sheath polybutadiene.

Rubber is a polymer material widely used in tires, conveyor belts, building materials, automobile parts, home appliances, shoes, coatings, medical and hygiene related products.

Rubber can be divided into natural rubber and synthetic rubber, and more than half of synthetic rubber is used for tires. Synthetic rubbers include styrene-butadiene rubber (SBR), butadiene rubber (BR), ethylene-propylene rubber, nitrile rubber, polychloroprene, silicone rubber and acrylic rubber, of which SBR accounts for about 35% of the production of synthetic rubber. It is used mainly for tire treads. In addition, BR accounts for about 25% of the production of synthetic rubber, mainly used for tire sidewalls.

Recently, as interest in eco-friendly and energy-saving high-performance tires has increased, trade-offs between dynamic properties such as rolling resistance and wetting resistance, mechanical properties, and workability are present. Research has been conducted in various ways to develop a high-performance rubber that can solve the problem.

In general, it is known that the interaction between the inorganic filler and the synthetic rubber, that is, the tire having high compatibility shows excellent performance. Representative inorganic fillers include silica and carbon black. In particular, silica has been spotlighted as an environmentally friendly tire material.

In connection with this, research has been actively conducted to improve the compatibility with the inorganic filler by chemically modifying the synthetic rubber using a compound containing a functional group having high compatibility with the inorganic filler.

SBR is divided into emulsion polymerization SBR (ESBR) prepared by emulsion polymerization and solution polymerization SBR (SSBR) prepared by living anion polymerization, according to the production method. In particular, SSBR is easy to introduce functional groups or control the microstructure and molecular weight, has the advantage of narrow molecular weight distribution.

BR is also classified into high cis BR (HBR) produced by Ziegler-Natta catalyst polymerization and low cis BR (LBR) produced by living anionic polymerization. In addition, HBR includes Nd-BR, Co-BR, Ni-BR, and the like, and LBR includes Li-BR depending on the catalyst used in the preparation.

HBR is difficult to chemically modify, so when mixed with the conventional SBR is used to modify the end of the SBR instead of HBR. According to US Patent No. 5508333, by modifying the end of the SBR with an alkoxysilane compound containing an epoxy group to improve the dynamic properties and mechanical properties, but there is a problem that difficult to control the coupling rate. Further, according to US Patent Publication No. 2010-0152369, the terminal of the SBR can be modified with an alkoxysilane compound containing a primary amine substituted with a hydrolyzable protecting group to reduce the hysteresis of the tire produced therefrom. In this case, there is a limit in terms of economics according to the application of the protector, and there is a problem in that long-term storage stability is lowered due to low temperature flowability.

On the other hand, LBR has a limited cis content, which is limited to use as a tire material. However, due to its easy chemical modification, interest in recently modified Li-BR (F-LiBR) is increasing.

Conventional four-season tires meet the needs of consumers as long as they can be used in spring, summer, and autumn, but in recent years, the demand is expanding to levels that can be used in winter. Seasonal tires are distinguished by the glass transition temperature of the tire, and winter tires should have a very low glass transition temperature. In order to lower the glass transition temperature of a tire, a raw rubber having a low glass transition temperature should be used, and since the content of styrene and vinyl should be low, the higher the content of BR in the raw rubber mixed with SBR and BR, the better.

The present invention is to solve the above-mentioned problems of the prior art, an object of the present invention is to modify the polybutadiene in an economical and easy way to improve compatibility with inorganic fillers, thereby improving the dynamic properties of the tire tread produced therefrom To provide a tire tread rubber composition that can significantly improve the mechanical properties, and wear resistance.

One aspect of the present invention, the content of the cis-1,4 bond is 10 to 50% by weight and 30 to 80% by weight of polybutadiene having a glass transition temperature of -100 to 50 ° C; And 20 to 70% by weight of the copolymer consisting of an aromatic vinyl monomer and a conjugated diene monomer; provides a tire tread rubber composition comprising a.

In one embodiment, the vinyl content of the polybutadiene may be 5 to 20% by weight.

In one embodiment, at least one end of the polybutadiene may be modified with an aminoalkoxysilane compound.

In one embodiment, the aminoalkoxysilane compound may be represented by the following formula (1).

<Formula 1>

In Formula 1, R is one of a saturated or unsaturated hydrocarbon chain of C ₁ ~ C _20, R 'is either one of C ₁ ~ saturated or unsaturated hydrocarbon chains of C _20, nitrogen, sulfur, or containing a halogen atom _One of the saturated or unsaturated hydrocarbon chains of C ₁ to C ₂₀ , and x is one of the integers of 1-3.

In one embodiment, the aminoalkoxysilane compound may be represented by the following formula (2).

<Formula 2>

In Chemical Formula 2, R ¹ to R ⁸ are each one of C ₁ to C ₂₀ saturated or unsaturated hydrocarbon chains, X is carbon, silicon, or nitrogen, a is 1 or 2, b, c, and d Is one of integers of 0 to 3 each satisfying b + c + d = 3, and n is one of integers of 1 to 200.

In one embodiment, the aminoalkoxysilane compound may be represented by the following formula (3).

<Formula 3>

In Formula 3, R ⁹ and R ¹⁰ is either one of a saturated or unsaturated hydrocarbon chain of C ₁ ~ C _20, respectively, nitrogen, sulfur, or any of halogen, saturated or unsaturated hydrocarbon chain of C ₁ ~ C ₂₀ containing atoms And R ¹¹ to R ¹³ are each one of C ₁ to C ₂₀ saturated or unsaturated hydrocarbon chains, and e and f are each one of an integer of 0 to 2, respectively.

In one embodiment, the aromatic vinyl monomer is styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4 -Propyl styrene, 4-cyclohexyl styrene, 4- (p-methylphenyl) styrene, 5-tert-butyl-2-methylstyrene, tert-butoxystyrene, 2-tert-butylstyrene, 3-tert-butylstyrene, 4-tert-butylstyrene, N, N-dimethylaminoethylstyrene, 1-vinyl-5-hexylnaphthalene, 1-vinylnaphthalene, divinylnaphthalene, divinylbenzene, trivinylbenzene, vinylbenzyldimethylamine, (4- Vinylbenzyl) dimethylaminoethylether, vinylpyridine, vinylxylene, diphenylethylene, diphenylethylene containing tertiary amines, styrene comprising primary, secondary, or tertiary amines and combinations of two or more thereof It may be one selected from the group consisting of.

In one embodiment, the conjugated diene monomer is 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 2-phenyl-1 , 3-butadiene, 3-methyl-1,3-pentadiene, 2-chloro-1,3-butadiene, 3-butyl-1,3-octadiene, octadiene and combinations of two or more thereof It can be one.

In one embodiment, the copolymer may be a styrene-butadiene copolymer having a styrene content of 20 to 50% by weight and a glass transition temperature of -10 to -60 ° C.

In one embodiment, the vinyl content of the styrene-butadiene copolymer may be 40 to 70% by weight.

The tire tread rubber composition according to an aspect of the present invention may be improved by compatibility with an inorganic filler by including a low sheath polybutadiene modified by a certain compound and the cis content and glass transition temperature are adjusted to a certain range. It is possible to significantly improve the dynamic, mechanical and abrasion resistance of the tire treads produced therefrom.

It is to be understood that the effects of the present invention are not limited to the above effects, and include all effects deduced from the configuration of the invention described in the detailed description or claims of the present invention.

Hereinafter, with reference to the accompanying drawings will be described the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

Throughout the specification, when a part is "connected" to another part, it includes not only "directly connected" but also "indirectly connected" with another member in between. . In addition, when a part is said to "include" a certain component, this means that it may further include other components, without excluding the other components unless otherwise stated.

One aspect of the present invention, the content of the cis-1,4 bond is 10 to 50% by weight and 30 to 80% by weight of polybutadiene having a glass transition temperature of -100 to 50 ° C; And 20 to 70% by weight of the copolymer consisting of an aromatic vinyl monomer and a conjugated diene monomer; provides a tire tread rubber composition comprising a.

The polybutadiene may have a cis-1,4 bond content, that is, a cis content of 10 to 50% by weight and a glass transition temperature of -100 to 50 ° C, preferably, 5 to 20% by weight of vinyl. Can be. If the cis content, glass transition temperature, and vinyl content of the polybutadiene are outside the above ranges, the mechanical properties and grip characteristics of the tire tread, such as the tensile strength of the tire tread, and 300% modulus are reduced, and the rolling resistance may be increased, thereby reducing the fuel efficiency characteristics. have.

At least one terminal of the polybutadiene may be modified with an aminoalkoxysilane compound. The aminoalkoxysilane compound may be substituted at at least one end of the polybutadiene to improve compatibility of the polybutadiene with silica in the tire tread rubber composition.

The aminoalkoxysilane compound may be represented by one or more of the following Chemical Formulas 1-3.

<Formula 1>

<Formula 2>

<Formula 3>

In Formula 1, R is one of a saturated or unsaturated hydrocarbon chain of C ₁ ~ C _20, R 'is either one of C ₁ ~ saturated or unsaturated hydrocarbon chains of C _20, nitrogen, sulfur, or containing a halogen atom _One of the saturated or unsaturated hydrocarbon chains of C ₁ to C ₂₀ , and x is one of the integers of 1-3.

Non-limiting examples of the compound represented by Formula 1 include (N, N-diethyl-3-aminopropyl) trimethoxysilane, (N, N-dimethyl-3-aminopropyl) trimethoxysilane, 3 -Chloropropyltriethoxysilane, 3-chloropropylmethyldiethoxysilane, 3-aminopropyltriethoxysilane, N- (2-aminoethyl) -3-aminopropyltrimethoxysilane, 3-aminopropylmethyldie Methoxysilane, trimethoxysilylpropanethiol, 3-glycidyloxypropylmethyldiethoxysilane, 3-glycidyloxypropyltriethoxysilane, 3-glycidyloxypropylmethyldimethoxysilane, 3-gly Cydoxypropyl trimethoxysilane or vinyl triethoxysilane.

In Chemical Formula 2, R ¹ to R ⁸ are each one of C ₁ to C ₂₀ saturated or unsaturated hydrocarbon chains, X is carbon, silicon, or nitrogen, a is 1 or 2, b, c, and d Is one of integers of 0 to 3 each satisfying b + c + d = 3, and n is one of integers of 1 to 200.

In particular, when a is 1 in Formula 2, since X has a sp ³ hybrid structure, nitrogen atoms are introduced into each of two branches extending from one X to generate two or more tertiary amine groups. When the rubber composition is blended, polybutadiene and silica are adjacent to each other by hydrogen bonding between silica, which is an inorganic filler, and the amine group. The hydrogen bonds and covalent bonds may enhance the chemical bonds between the polybutadiene and silica to improve dynamic and mechanical properties such as grip and rolling resistance required for the tire tread.

The compound represented by Chemical Formula 2 may be prepared by the route of Scheme 1 or Scheme 2 according to the element X. In Scheme 1 and Scheme 2, R ¹ to R ⁸ are each one of C ₁ to C ₂₀ saturated or unsaturated hydrocarbon chains, X is carbon, silicon, or nitrogen, and L is any leaving group. A is 1 or 2, b, c, and d are each one of integers of 0 to 3 satisfying b + c + d = 3, and n is one of integers of 1 to 200.

Scheme 1

First, when the element X is nitrogen, an aminoalkoxysilane compound may be prepared by a nucleophilic substitution reaction represented by Scheme 1 in the presence of a base. At this time, the reaction temperature may be adjusted in the range of -30 ~ 150 ℃. As the base, hydrides, hydroxides, carbonates, or bicarbonates of alkali metals or alkaline earth metals may be used. Specifically, sodium hydride (NaH) or sodium hydroxide (NaOH) may be used. As the reaction solvent, a polar organic solvent such as dimethylformaldehyde may be used to increase the solubility of the reactants.

Scheme 2

In addition, when the element X is carbon or silicon and cannot act as a nucleophile, that is, when a nucleophilic substitution reaction cannot be performed, the hydrosilylation reaction represented by Scheme 2 under a platinum (Pt) catalyst is performed. An aminoalkoxysilane compound can be manufactured by this. At this time, the reaction temperature may be a reflux temperature, which may vary depending on the type of reaction solvent used, but may be controlled in a range of about 100 to 180 ° C. The kind of reaction solvent is not particularly limited, but it is preferable to use an aromatic solvent such as benzene and toluene.

Non-limiting examples of the compound represented by Formula 2 include N ¹ , N ¹ -diethyl-N ² , N ² -bis (3- (trimethoxysilyl) propyl) ethane-1,2-diamine, or 6- (2- (dimethylamino) ethyl) -N ¹ , N ¹ , N ¹⁰ , N ¹⁰ -tetramethyl-3- (3- (trimethoxysilyl) propyl) decane-1,10-diamine have.

In Formula 3, R ⁹ and R ¹⁰ is either one of a saturated or unsaturated hydrocarbon chain of C ₁ ~ C _20, respectively, nitrogen, sulfur, or any of halogen, saturated or unsaturated hydrocarbon chain of C ₁ ~ C ₂₀ containing atoms And R ¹¹ to R ¹³ are each one of C ₁ to C ₂₀ saturated or unsaturated hydrocarbon chains, and e and f are each one of an integer of 0 to 2, respectively.

When the rubber composition is blended using the polybutadiene modified with the compound represented by Formula 3, the polybutadiene and the silica are adjacent to each other by hydrogen bonding between the inorganic filler silica and the amine group. Covalent bonds may be formed between the alkoxysilane group and the silica. In addition, the allyl group or the epoxy group may improve the dynamic and mechanical properties such as grip and rotational resistance required for the tire tread by strengthening the crosslinking between the polybutadiene and silica.

Non-limiting examples of the compound represented by the formula (3) include N, N-diallylaminopropyltrimethoxysilane or N, N-diglycidopropyl trimethoxysilane.

The copolymer may consist of an aromatic vinyl monomer and a conjugated diene monomer.

The aromatic vinyl monomers are styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4-propylstyrene, 4- Cyclohexyl styrene, 4- (p-methylphenyl) styrene, 5-tert-butyl-2-methylstyrene, tert-butoxystyrene, 2-tert-butylstyrene, 3-tert-butylstyrene, 4-tert-butylstyrene , N, N-dimethylaminoethylstyrene, 1-vinyl-5-hexylnaphthalene, 1-vinylnaphthalene, divinylnaphthalene, divinylbenzene, trivinylbenzene, vinylbenzyldimethylamine, (4-vinylbenzyl) dimethylaminoethyl One selected from the group consisting of ether, vinylpyridine, vinylxylene, diphenylethylene, diphenylethylene comprising tertiary amine, styrene comprising primary, secondary or tertiary amine and combinations of two or more thereof It may be, and preferably, may be styrene, but is not limited thereto.

On the other hand, the polybutadiene, (a) polymerizing butadiene in the presence of a solvent, a Lewis base and an organometallic compound to form a living polymer; And (b) injecting the aminoalkoxysilane compound represented by one or more of Chemical Formulas 1 to 3 to the living polymer to modify the terminal of the living polymer, by the method comprising the aminoalkoxysilane compound, Can be modified. The method may be continuous or batch, and preferably, but not limited thereto.

Step (a) is a step of forming a living polymer according to a conventional solution polymerization method. Specifically, it is performed in the presence of a solvent, a Lewis base and an organometallic compound, and butadiene may be used as the monomer.

The solvent usable in step (a) may be one selected from the group consisting of aliphatic hydrocarbons, cyclic aliphatic hydrocarbons, aromatic hydrocarbons, and combinations of two or more thereof, preferably n-pentane, n- Hexane, n-heptane, isooctane, cyclohexane, toluene, benzene, xylene and may be one selected from the group consisting of two or more of these, more preferably, may be cyclohexane, but is not limited thereto.

The Lewis base is a material used to control the microstructure of the polymer, tetrahydrofuran, di-n-propyl ether, diisopropyl ether, diethyl ether, diethylene glycol dimethyl ether, di-n-butyl ether, Ethylbutyl ether, triethylene glycol, 1,2-dimethoxybenzene, ditetrahydrofurylpropane, ditetrahydrofurfurylpropane, ethyltetrahydrofurfurylether, trimethylamine, triethylamine, N, N, N, N It may be one selected from the group consisting of tetramethylethylenediamine and a combination of two or more thereof, preferably, ethyl tetrahydrofurfuryl ether, tetrahydrofuran, ditetrahydrofurfuryl propane, ditetrahydrofurylpropane, or N, N, N, N-tetramethylethylenediamine, but is not limited thereto. The dosage of the Lewis base can be adjusted according to the number of moles of total anions and the vinyl content in the polybutadiene targeted at the onset temperature conditions.

The organometallic compound serving as a polymerization initiator in step (a) is one selected from the group consisting of an organolithium compound, an organosodium compound, an organopotassium compound, an organorubidium compound, an organocesium compound, and a combination of two or more thereof It may be, preferably, may be an organolithium compound, more preferably, an alkyllithium compound having an alkyl group having 1 to 20 carbon atoms. The alkyllithium compound which can be used may be one selected from the group consisting of methyllithium, ethyllithium, isopropyllithium, n-butyllithium, sec-butyllithium, tert-butyllithium, and combinations of two or more thereof, preferably , n-butyllithium or sec-butyllithium, but is not limited thereto. The amount of the organometallic compound may vary depending on the target molecular weight of the polybutadiene, but in general, 0.01 to 10 mmol, preferably 0.1 to 3.0 mmol based on 100 g of the monomer.

In step (a), the onset temperature of the polymerization reaction during solution polymerization may be about 10 to 100 ° C, preferably about 20 to 90 ° C. If the starting temperature is less than 10 ℃ as the reaction proceeds as the viscosity of the solution rises rapidly and the reaction rate decreases economically disadvantageous, if it exceeds 100 ℃ it is difficult to control the reaction. In addition, the reaction pressure may be 0.5 ~ 10kgf / cm ² . In general, the polymerization reaction can take place for a sufficient time until all of the monomers are converted into the polymer, ie until the desired conversion is achieved.

Step (b) is a step of denaturing the terminal of the living polymer by reacting the living polymer formed in the step (a) and the aminoalkoxysilane compound.

The aminoalkoxysilane compound may be used in the range of 0.5 to 5.0 moles per mole of the organometallic compound. When the relative amount of the organometallic compound is less than 0.5 mole, the modifying effect of the living polymer may be insignificant, and when it is more than 5.0 mole, the production cost may be increased.

In addition, the reaction temperature in the step (b) may be 30 ~ 200 ℃, preferably, 50 ~ 110 ℃. If the reaction temperature is less than 30 ℃ the reaction proceeds as the viscosity of the solution rises to reduce the reaction rate, if it exceeds 200 ℃ the living polymer is a coupling reaction by itself, the modification effect of the aminoalkoxysilane compound is weak. Can be.

The conjugated diene monomer is 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 2-phenyl-1,3-butadiene, 3 May be selected from the group consisting of -methyl-1,3-pentadiene, 2-chloro-1,3-butadiene, 3-butyl-1,3-octadiene, octadiene, and combinations of two or more thereof, preferably Preferably, it may be 1,3-butadiene, but is not limited thereto.

When the aromatic vinyl monomer and the conjugated diene monomer are styrene and 1,3-butadiene, respectively, the copolymer may be a styrene-butadiene copolymer, preferably a styrene-butadiene rubber.

The styrene-butadiene copolymer has a styrene content of 20 to 50% by weight, a glass transition temperature of -10 to -60 ° C, and a vinyl content of 40 to 70% by weight. When the styrene content, the glass transition temperature, and the vinyl content of the styrene-butadiene copolymer are outside the above ranges, the grip characteristics of the tire tread may be lowered, and the rolling resistance may be increased, thereby lowering the fuel efficiency characteristics.

The tire tread rubber composition may further include an inorganic filler, and the inorganic filler may be, for example, silica, carbon black, or a combination thereof.

Hereinafter, embodiments of the present invention will be described in detail. Materials used in Examples and Comparative Examples of the present invention are as follows.

SSBR1: 28 wt% styrene, 56 wt% vinyl, Tg -26 ° C

SSBR2: 15% by weight of styrene, 30% by weight of vinyl, Tg -62 ° C

-BR1: neodymium butadiene rubber, sheath 97% by weight, vinyl 1% by weight, Tg -105 ℃

-BR2: ((N, N-diethyl-3-aminopropyl) trimethoxysilane-modified low sheath butadiene rubber) 38% by weight sheath, 12% by weight vinyl, Tg -92 ° C

Silica: Degussa 7000GR

-X50S: 50% by weight of Evonik Si69

Oil: TDEA Oil

-DPG: 1,3-diphenylguanidine

-CZ: N-cyclohexylbenzothiazylsulfenamide

Example 1

80 parts by weight of silica, 2 parts by weight of stearic acid, 3 parts by weight of zinc oxide, 45 parts by weight of oil based on 100 parts by weight of the raw material rubber including 20 parts by weight of solution-polymerized styrene-butadiene rubber (SSBR1) and 80 parts by weight of butadiene rubber (BR2). 2 parts by weight of sulfur, vulcanizing agent, and DPG and CZ, vulcanizing accelerator, were mixed in a closed Banbury mixer each 1.5 parts by weight to prepare a masterbatch, and then a mixed rubber was produced in an open twin screw mill for 20 minutes at 165 ° C. Lively vulcanized to prepare rubber specimens.

Example 2

80 parts by weight of silica, 2 parts by weight of stearic acid, 3 parts by weight of zinc oxide, 45 parts by weight of oil based on 100 parts by weight of the raw material rubber including 30 parts by weight of solution-polymerized styrene-butadiene rubber (SSBR1) and 70 parts by weight of butadiene rubber (BR2). 2 parts by weight of sulfur, vulcanizing agent, and DPG and CZ, vulcanizing accelerator, were mixed in a closed Banbury mixer each 1.5 parts by weight to prepare a masterbatch, and then a mixed rubber was produced in an open twin screw mill for 20 minutes at 165 ° C. Lively vulcanized to prepare rubber specimens.

Example 3

80 parts by weight of silica, 2 parts by weight of stearic acid, 3 parts by weight of zinc oxide, 45 parts by weight of oil based on 100 parts by weight of the raw material rubber including 50 parts by weight of solution-polymerized styrene-butadiene rubber (SSBR1) and 50 parts by weight of butadiene rubber (BR2). 2 parts by weight of sulfur, vulcanizing agent, and DPG and CZ, vulcanizing accelerator, were mixed in a closed Banbury mixer each 1.5 parts by weight to prepare a masterbatch, and then a mixed rubber was produced in an open twin screw mill for 20 minutes at 165 ° C. Lively vulcanized to prepare rubber specimens.

Example 4

80 parts by weight of silica, 2 parts by weight of stearic acid, 3 parts by weight of zinc oxide, 45 parts by weight of oil based on 100 parts by weight of the raw material rubber including 70 parts by weight of solution-polymerized styrene-butadiene rubber (SSBR1) and 30 parts by weight of butadiene rubber (BR2). 2 parts by weight of sulfur, vulcanizing agent, and DPG and CZ, vulcanizing accelerator, were mixed in a closed Banbury mixer each 1.5 parts by weight to prepare a masterbatch, and then a mixed rubber was produced in an open twin screw mill for 20 minutes at 165 ° C. Heavily vulcanized to prepare rubber specimens.

Comparative Example 1

80 parts by weight of silica, 2 parts by weight of stearic acid, 3 parts by weight of zinc oxide, 45 parts by weight of oil based on 100 parts by weight of the raw material rubber including 30 parts by weight of solution-polymerized styrene-butadiene rubber (SSBR1) and 70 parts by weight of butadiene rubber (BR1). 2 parts by weight of sulfur, a vulcanizing agent, and DPG and CZ, vulcanization accelerators, were mixed in a closed Banbury mixer each 1.5 parts by weight to prepare a masterbatch, and then a mixed rubber was prepared in an open twin screw mill for 20 minutes at 165 ° C. Lively vulcanized to prepare rubber specimens.

Comparative Example 2

80 parts by weight of silica, 2 parts by weight of stearic acid, 3 parts by weight of zinc oxide, 45 parts by weight of oil based on 100 parts by weight of the raw material rubber including 70 parts by weight of solution-polymerized styrene-butadiene rubber (SSBR1) and 30 parts by weight of butadiene rubber (BR1). 2 parts by weight of sulfur, vulcanizing agent, and DPG and CZ, vulcanizing accelerator, were mixed in a closed Banbury mixer each 1.5 parts by weight to prepare a masterbatch, and then a mixed rubber was produced in an open twin screw mill for 20 minutes at 165 ° C. Lively vulcanized to prepare rubber specimens.

Comparative Example 3

80 parts by weight of silica, 2 parts by weight of stearic acid, 3 parts by weight of zinc oxide, 45 parts by weight of oil based on 100 parts by weight of the raw material rubber including 70 parts by weight of solution-polymerized styrene-butadiene rubber (SSBR2) and 30 parts by weight of butadiene rubber (BR1). 2 parts by weight of sulfur, vulcanizing agent, and DPG and CZ, vulcanizing accelerator, were mixed in a closed Banbury mixer each 1.5 parts by weight to prepare a masterbatch, and then a mixed rubber was produced in an open twin screw mill for 20 minutes at 165 ° C. Lively vulcanized to prepare rubber specimens.

Comparative Example 4

80 parts by weight of silica, 2 parts by weight of stearic acid, 3 parts by weight of zinc oxide, 45 parts by weight of oil based on 100 parts by weight of the raw material rubber including 70 parts by weight of solution-polymerized styrene-butadiene rubber (SSBR2) and 30 parts by weight of butadiene rubber (BR2). 2 parts by weight of sulfur, vulcanizing agent, and DPG and CZ, vulcanizing accelerator, were mixed in a closed Banbury mixer each 1.5 parts by weight to prepare a masterbatch, and then a mixed rubber was produced in an open twin screw mill for 20 minutes at 165 ° C. Lively vulcanized to prepare rubber specimens.

The compositions of the materials used in the examples and comparative examples are shown in Table 1 below.

division Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 SSBR1 20 30 50 70 30 70 - - SSBR2 - - - - - - 70 70 BR1 - - - - 70 30 30 - BR2 80 70 50 30 - - - 30 Stearic acid 2 2 2 2 2 2 2 2 Zinc oxide 3 3 3 3 3 3 3 3 Silica 80 80 80 80 80 80 80 80 X50S 12.8 12.8 12.8 12.8 12.8 12.8 12.8 12.8 oil 45 45 45 45 45 45 45 45 Sulfur (S) 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 DPG 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 CZ 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5

(Unit: parts by weight) Experimental example

The rubber specimens of Examples and Comparative Examples were measured and evaluated for hardness, tensile strength, 300% modulus, elongation, dynamic properties, and abrasion according to ASTM-related regulations, and the results are shown in Tables 2 and 3 below.

The grip characteristics, in particular, the ice grip and the wet grip were judged to be superior to the higher Tanδ value at -20 ° C and 0 ° C, respectively, and the rolling resistance was lower at 60 ° C. It was judged that the better. In addition, abrasion loss is the percentage of rubber lost after testing at Slip 30%, 40N, 80m / s using a Lambbourn abrasion tester. The lower the value, the better. .

division Example 1 Example 2 Example 3 Example 4 Hardness (SHORE-A) 58 58 58 58 Tensile Strength (kgf / cm ² ) 200 184 192 177 300% modulus (kgf / cm ² ) 66 66 75 86 Elongation (%) 560 550 540 480 Glass transition temperature (℃) -58 -48 -32 -23 Tanδ @ -20 ℃ (Ice grip) 0.2405 0.3058 0.5055 0.8213 Tanδ @ 0 ℃ (wet grip) 0.1515 0.1675 0.2262 0.3137 Tanδ @ 60 ℃ (Rotational Resistance) 0.0896 0.0918 0.0944 0.1024 Wear loss (%) 0.1665 0.1715 01938 0.1962

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Hardness (SHORE-A) 59 59 58 59 Tensile Strength (kgf / cm ² ) 180 174 189 182 300% modulus (kgf / cm ² ) 61 78 60 76 Elongation (%) 580 530 560 500 Glass transition temperature (℃) -58 -32 -49 -38 Tanδ @ -20 ℃ (Ice grip) 0.2215 0.4845 0.2568 0.4781 Tanδ @ 0 ℃ (wet grip) 0.1511 0.2054 0.1882 0.2075 Tanδ @ 60 ℃ (Rotational Resistance) 0.1292 0.1124 0.1250 0.1117 Wear loss (%) 0.1602 0.1925 0.1801 0.1914

In Table 2 and Table 3, when the glass transition temperature of the Examples and Comparative Examples are the same or similar, specifically, the rubber of Example 1 and Comparative Examples 1, 2 and Comparative Examples 3, 3 and 2 Comparing the physical properties of the specimens, the rubber specimens of Examples 1, 2 and 3 have all improved grip characteristics, fuel economy characteristics and abrasion resistance compared to Comparative Examples 1, 3 and 2.

In addition, the rubber specimen of the embodiment includes up to 80% by weight of functionalized low sheath butadiene rubber in the raw material rubber, low glass transition temperature, high compatibility with silica, high fuel efficiency characteristics, grip while maintaining mechanical properties and wear resistance The properties are significantly improved.

As described above, the tire tread rubber composition according to the present invention is suitable for low rolling resistance (LRR) tires because of the low tan δ value and high stiffness at high temperatures, and the high tan δ value at low temperatures to increase moisture and Since it is advantageous to environmental conditions such as ice friction, it is suitable for four-season tires having excellent fuel efficiency, particularly for winter snow tire treads.

The foregoing description of the present invention is intended for illustration, and it will be understood by those skilled in the art that the present invention may be easily modified in other specific forms without changing the technical spirit or essential features of the present invention. will be. Therefore, it should be understood that the embodiments described above are exemplary in all respects and not restrictive. For example, each component described as a single type may be implemented in a distributed manner, and similarly, components described as distributed may be implemented in a combined form.

The scope of the invention is indicated by the following claims, and it should be construed that all changes or modifications derived from the meaning and scope of the claims and their equivalents are included in the scope of the invention.

Claims (10)

30 to 80% by weight of polybutadiene having a cis-1,4 bond content of 10 to 50% by weight and a glass transition temperature of -100 to 50 ° C; And
A tire tread rubber composition comprising a vinyl content of 40 to 70% by weight and a copolymer of 20 to 70% by weight of an aromatic vinyl monomer and a conjugated diene monomer. The method of claim 1,
The vinyl tread rubber composition of the polybutadiene is 5 to 20% by weight. The method of claim 1,
At least one end of the polybutadiene is a tire tread rubber composition modified with an aminoalkoxysilane compound. The method of claim 3,
The aminoalkoxysilane compound is a tire tread rubber composition represented by the following formula (1):
<Formula 1>

In Chemical Formula 1,
R is _one of the saturated or unsaturated hydrocarbon chains of C ₁ to C ₂₀ ,
R 'is C ₁ ~ C ₂₀ or one of the saturated or unsaturated hydrocarbon chain, nitrogen, sulfur, or any of halogen, saturated or unsaturated hydrocarbon chain of C ₁ ~ C ₂₀ containing the atom,
x is one of the integers of 1-3. The method of claim 3,
The aminoalkoxysilane compound is a tire tread rubber composition represented by the following formula (2):
<Formula 2>

In Chemical Formula 2,
R ¹ to R ⁸ are each one of C ₁ to C ₂₀ saturated or unsaturated hydrocarbon chains,
X is carbon, silicon, or nitrogen,
a is 1 or 2,
b, c, and d are each one of integers of 0 to 3 satisfying b + c + d = 3,
n is one of the integers of 1-200. The method of claim 3,
The aminoalkoxysilane compound is a tire tread rubber composition represented by the following formula (3):
<Formula 3>

In Chemical Formula 3,
R ⁹ and R ¹⁰ are each C ₁ ~ C ₂₀ or one of the saturated or unsaturated hydrocarbon chain, nitrogen, sulfur, or any of halogen, saturated or unsaturated hydrocarbon chain of C ₁ ~ C ₂₀ containing the atom,
R ¹¹ to R ¹³ are each one of C ₁ to C ₂₀ saturated or unsaturated hydrocarbon chains,
e and f are each an integer of 0-2. The method of claim 1,
The aromatic vinyl monomers are styrene, α-methylstyrene, 2-methylstyrene, 3-methylstyrene, 4-methylstyrene, 2,4-dimethylstyrene, 2,4-diisopropylstyrene, 4-propylstyrene, 4- Cyclohexyl styrene, 4- (p-methylphenyl) styrene, 5-tert-butyl-2-methylstyrene, tert-butoxystyrene, 2-tert-butylstyrene, 3-tert-butylstyrene, 4-tert-butylstyrene , N, N-dimethylaminoethylstyrene, 1-vinyl-5-hexylnaphthalene, 1-vinylnaphthalene, divinylnaphthalene, divinylbenzene, trivinylbenzene, vinylbenzyldimethylamine, (4-vinylbenzyl) dimethylaminoethyl One selected from the group consisting of ether, vinylpyridine, vinylxylene, diphenylethylene, diphenylethylene containing tertiary amine, styrene comprising primary, secondary or tertiary amine and combinations of two or more thereof Tire tread rubber composition. The method of claim 1,
The conjugated diene monomer is 1,3-butadiene, isoprene, 2,3-dimethyl-1,3-butadiene, 1,3-pentadiene, 1,3-hexadiene, 2-phenyl-1,3-butadiene, 3 Tire tread rubber composition, which is one selected from the group consisting of -methyl-1,3-pentadiene, 2-chloro-1,3-butadiene, 3-butyl-1,3-octadiene, octadiene and combinations of two or more thereof . The method of claim 1,
The copolymer is a tire tread rubber composition is a styrene-butadiene copolymer having a styrene content of 20 to 50% by weight and a glass transition temperature of -10 to -60 ℃. delete