KR102424972B1 - Rubber composition and manufacturing method for the same - Google Patents

Abstract

The present invention relates to a rubber composition and a method for producing the same, to prepare a rubber composition comprising 38 wt% or more of silica as a rubber component and a reinforcing filler comprising a modified conjugated diene-based polymer in which a modifier is introduced at an active end of the polymer By doing so, it relates to a rubber composition excellent in physical properties such as rolling resistance, abrasion resistance and braking properties.

Description

RUBBER COMPOSITION AND MANUFACTURING METHOD FOR THE SAME

The present invention relates to a rubber composition having excellent physical properties such as heat generation, abrasion and braking properties, and a method for manufacturing the same.

Recently, as interest in environmental issues has increased, carbon dioxide emissions are being regulated worldwide. Accordingly, the demand for low fuel efficiency of automobiles is getting stronger. In order to meet these demands, it is necessary to reduce the rolling resistance of the tire performance. As a method of reducing the rolling resistance of a tire, a method of optimizing the tire structure has also been studied, but the most common method is to use a material having low heat generation properties as a rubber composition.

In order to obtain compounded rubber with low exothermicity, many technological developments have been made to improve the dispersibility of fillers used in rubber compositions. Among them, a method of modifying the terminal of a diene polymer obtained by anionic polymerization using alkyl lithium as an initiator with a functional group having strong interaction with a filler is not widely used. As representative of these methods, a method of introducing a Sn functional group, various amino groups, and alkoxysilanes by anionic polymerization is generally performed.

In addition, as interest in the safety of automobiles has recently increased, the demand level for performance on a wet road surface (hereinafter also referred to as 'wet braking performance') as well as low fuel consumption characteristics has increased. For this reason, performance requirements for a rubber composition for a tire are not limited to simply reducing rolling resistance, but are required to simultaneously satisfy braking performance and low fuel consumption performance.

In general, in order to improve wet braking performance, a compounding method of increasing the glass transition temperature of compounded rubber is used. However, as the glass transition temperature rises, the grip performance at low temperatures significantly deteriorates, so there is a limit.

As a method of obtaining a rubber composition that simultaneously provides a tire with good grip and wet performance even at low temperatures, a method of blending carbon black as a reinforcing filler has been used, and recently a method of using silica instead of carbon black has been used. have.

However, it has been found that when silica is used as a reinforcing filler, the breaking strength and abrasion resistance of the rubber composition are significantly reduced. As additional requirements for safety have recently increased, an attempt has been made to achieve better wet braking performance by incorporating a large amount of silica as a reinforcing filler beyond the conventionally used content range as a solution to this.

However, when a large amount of silica is blended, it is possible to obtain good wet braking properties, but the blend itself is very difficult, and properties such as fuel efficiency and abrasion resistance are deteriorated due to heat generation of the tire.

Japanese Patent Publication No. 6053763 suggests a method of using amino alkoxy silane as a modifier at the end of a polymer for mixing silica, but even here, when a large amount of silica is blended into a rubber raw material, sufficient effect cannot be obtained.

Japanese Patent No. 6053763 (2016.12.09)

In consideration of the above points, the present invention provides a polymer using an alkoxysilane compound having a methylene amino group and an alkoxysilane compound having a cyclic amine as a terminal modifier, and a large amount of silica in the total rubber composition of 30% by weight or more. To provide a rubber composition for a tire tread capable of not only reducing the rolling resistance of a tire by improving silica dispersibility and reinforcing properties with the rubber composition, but also satisfying wet braking performance and low fuel consumption performance at the same time, and a method for manufacturing the same The purpose.

In order to achieve the above object, the rubber composition of the present invention preferably includes a rubber component including a modified conjugated diene-based polymer in which a modifier is introduced at the active end of the polymer, and silica as a reinforcing filler.

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The modified conjugated diene-based polymer may be a compound represented by the following formula (4).

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[Formula 4]

In Chemical Formula 4, Polymer is a conjugated diene-based polymer chain. In Chemical Formula 4, R ₁ is a methyl group, and R ₂ is an isobutyl group.

Based on the total weight of the rubber composition, the silica is preferably included in 38 wt% to 45 wt%.

In the rubber component, the modified conjugated diene-based polymer preferably contains 50 wt% or more.

The rubber component may include one or more synthetic rubbers selected from among styrene-butadiene copolymers, polybutadiene rubbers, polyisoprene rubbers, butyl rubbers, and ethylene-propylene copolymers, natural rubbers, and mixtures thereof. .

The rubber composition may further include an additive, and as the additive, any one or more selected from carbon black, silane coupling agent, process oil, vulcanization accelerator, zinc oxide, stearic acid, antioxidant, and ozone-resistance inhibitor is used. It is preferable to do

The method for producing a rubber composition of the present invention for achieving another object comprises the steps of (a) polymerizing a conjugated diene-based monomer and a vinyl aromatic monomer in a hydrocarbon solvent using a polymerization initiator to form a polymer having an active end, (b) ) preparing a substituted conjugated diene-based polymer by introducing a modifier to the active end of the polymer using a terminal modifier, and (c) mixing a rubber component including the modified conjugated diene-based polymer and silica to obtain a rubber composition It is preferable to include the step of preparing.

In step (b), the terminal modifier may be one of the following Chemical Formula 1 or Chemical Formula 2.

[Formula 1]

In Formula 1, R ₁ is a methyl group, R ₂ is an isobutyl group, and OEt is an ethoxy group.

[Formula 2]

The modified conjugated diene-based polymer may be represented by Formula 4 above.

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In step (c), the silica may be included in an amount of 38 wt% to 50 wt% based on the total weight of the rubber composition.

Based on the total weight of the rubber component in step (c), the modified conjugated diene-based polymer preferably contains 50 wt% or more.

In addition to the modified conjugated diene-based polymer, the rubber component includes at least one synthetic rubber selected from among styrene-butadiene copolymer, polybutadiene rubber, polyisoprene rubber, butyl rubber, and ethylene-propylene copolymer, natural rubber, and mixtures thereof. included can be used.

The rubber composition may further include an additive, and as the additive, any one or more selected from carbon black, silane coupling agent, process oil, vulcanization accelerator, zinc oxide, stearic acid, antioxidant, and ozone-resistance inhibitor is used. to prepare a rubber composition.

According to the present invention, a rubber composition having excellent rolling resistance, abrasion resistance and braking properties can be obtained by using a large amount of silica and combining a modified conjugated diene-based polymer whose ends are modified with a specific modifier.

In addition, when a tire is manufactured using a rubber composition having such characteristics, it is possible to manufacture a tire having excellent rolling resistance, abrasion resistance and braking characteristics.

1 is a flowchart of a method for manufacturing a rubber composition according to an embodiment of the present invention.

The present invention relates to a rubber composition comprising a conjugated diene-based polymer modified with a polymer having a terminal modifier having very strong basicity so that excellent interaction can be expressed even when a large amount of silica is mixed, and a method for producing the same.

As shown in FIG. 1 , the method for preparing a rubber composition according to an embodiment of the present invention includes (a) forming a polymer having an active end (S100), (b) a modified conjugate in which the active end of the polymer is substituted The steps of preparing a diene-based polymer (S200), and (c) mixing a rubber component including the modified conjugated diene-based polymer and silica to prepare a rubber composition (S300) are performed.

Specifically, (a) step (S100) is an activity for preparing a modified conjugated diene-based polymer by polymerizing or copolymerizing a conjugated diene monomer and a vinyl aromatic monomer using an organolithium compound as a polymerization initiator in a hydrocarbon solvent. Forms a polymer with a terminus.

The polymer formed in (a) step (S100) is a homopolymer formed by polymerization with only a conjugated diene-based monomer, or a copolymer formed by copolymerization with a conjugated diene-based monomer and a vinyl aromatic monomer, or a conjugated diene-based monomer and a vinyl It may be a random copolymer in which the aromatic monomer is anionically polymerized.

Monomers of the conjugated diene polymer include 1,3-butadiene, 2,3-dimethyl-1,3-butadiene, piperylene, 3-butyl-1,3-octadiene, isoprene and 2-phenyl-1,3- Any one or more selected from butadiene may be used, and 1,3-butadiene is preferable in consideration of excellent anionic polymerizability such as ease of supply and demand and activity of the polymer terminal during polymerization.

The vinyl aromatic hydrocarbon monomer used for copolymerization with the conjugated diene monomer is styrene, α-methylstyrene, 3-methylstyrene, 4-methylstyrene, 4-propylstyrene, 1-vinylnaphthalene, 4-cyclohexylstyrene, 4-( It may be any one selected from p-methylphenyl)styrene, and 1-vinyl-5-hexylnaphthalene, and it is recommended to use styrene in consideration of its excellent anionic polymerizability such as ease of supply and demand and activity of the polymer terminal during polymerization. desirable.

The hydrocarbon solvent used in the polymerization reaction in step (a) (S100) is a solvent in which the organolithium initiator is not destroyed, for example, n-pentane, n-hexane, Any one selected from n-heptane, isooctane, cyclohexane, toluene, benzene, and xylene may be used.

In the (a) step (S100), based on 100 wt% of the total hydrocarbon solvent, 5 wt% to 50 wt% of the monomer may be used, and preferably 10 wt% to 30 wt% may be used.

In the polymerization method of step (a) (S100), the polymerization reaction may be performed at a set temperature by adding an initiator, wherein the polymerization temperature is about -80 to 150 °C, preferably -20 to 100 °C at any temperature. can be polymerized in Although the polymerization reaction may be carried out under a pressure naturally created due to the heat of reaction, it is generally preferred to operate at a pressure sufficient to keep the monomer in the liquid phase. The reaction pressure will depend on the particular material being polymerized, the solvent used and the polymerization temperature, but higher pressures may be used if desired, and this pressure is obtained by filling and pressurizing the reactor with a gas that is inert to the polymerization reaction.

The initiator used for polymerization in step (a) (S100) is a hydrocarbon compound containing lithium metal, which is an organolithium compound, and a hydrocarbon lithium compound having 2 to 20 carbon atoms may be preferably used. For example, butyllithium may be used.

The amount of the initiator may be used in the range of 0.2 mmol to 20 mmol per 100 g of the monomer used, but is not necessarily limited thereto.

When performing anionic polymerization of the conjugated diene monomer in step (a) (S100), a randomizing agent may be used. Here, the "randomizing agent" is a substance having the purpose of controlling the microstructure of the conjugated diene-based polymer, and is a compound having a function of controlling the composition distribution of monomer units of the vinyl aromatic hydrocarbon copolymer. For example, the randomizing agent controls the random distribution of styrene and butadiene monomer units in the butadiene-styrene copolymer.

The randomizing agent is not limited to a particular kind, and includes all commonly used randomizing agents. For example, dimethoxybenzene, tetrahydrofuran, dimethoxyethane, diethylene glycol dibutyl ether, diethylene glycol dimethyl ether, bisterahydrofuryl propane, triethylamine, pyridine, N-methylmorpholine, N,N, N',N'-tetramethyl ethylene diamine, 1,2-dipyrrole. Also included are ethers and tertiary amines such as 2-dipiperidinoethane. As well as potassium salts such as potassium-t-amylate and potassium-t-butoxide and sodium salts such as sodium-t-amylate can be used.

The randomizing agent is preferably used in an amount of 0.01 to 1000 molar equivalents per 1 molar equivalent of the organolithium compound, which is an initiator of the polymerization reaction.

In step (a) (S100), it is preferable to remove substances that are toxic to catalyst activity, including water, oxygen, and carbon dioxide, from all substances involved in the polymerization process, such as initiator components, solvents, and monomers.

The polymer or copolymer obtained through (a) step (S100) has a glass transition point (Tg) measured by differential scanning calorimetry (DSC) of -90°C to -30°C. Under normal anionic polymerization conditions, it is difficult to obtain a polymer having a glass transition temperature of -90°C or lower, and a polymer having a temperature of -30°C or higher becomes hard in the room temperature region and is difficult to use as a rubber composition.

and the Mooney viscosity (ML1 + 4, 100° C.) of the polymer is 10 to 150, preferably 15 to 70. If the Mooney viscosity is less than 10, the rubber performance cannot be sufficiently obtained in terms of breaking performance, and if it exceeds 150, the processability is poor and mixing with the added compounding agent is difficult.

(b) step (S200) prepares a modified conjugated diene-based polymer by adding a terminal modifier to the polymer formed in step (a) (S100) to substitute a functional group at the active end of the polymer.

The terminal modifier is a compound having excellent basicity and almost no steric hindrance, and is a compound having various acidic functional groups and a functional group capable of exhibiting excellent hydrophobic bonding strength, and an alkoxysilane compound having a methylene amino group represented by Formula 1 or a cyclic represented by Formula 2 Alkoxy silane compounds with amines can be used.

The terminal modifier is, for example, a methylene amino group, an ethylidene amino group, a methyl propylidene amino group, a 1,3-dimethyl butylidene amino group, a 1-methylethylidene amino group, and 4-N, An alkoxyl silane compound including at least one functional group selected from N-dimethyl amino benzylidene amino group may be used.

In Formula 1, R ₁ is a methyl group, R ₂ is an isobutyl group, and OEt is an ethoxy group.

Specific examples of the compound containing a methylene amino group as the terminal modifier include (1,3-dimethyl butylidene)-3-(triethoxy silyl)-1-propanamine and N-(1-methylethylidene)-3 - (triethoxy silyl) is mentioned. Propanamine, N-ethylidene-3-(triethoxy silyl)-1-propanamine, N-(1-methyl propylidene)-3-(triethoxy)silyl)-1-propanamine, N-( 4-N,N-dimethyl amino benzylidene)-3-(triethoxy silyl)-1-propanamine, and N-(1-methyl propylidene)-3-(triethoxysilyl)-1-propanamine , N-(1,3-dimethyl butylidene)-3-(triethoxy silyl)-1-propanamine and the like.

In addition, as the terminal modifier, dihydroimidazolidyl propyl triethoxy silane represented by the following Chemical Formula 2 may be used as a modifier. This denaturant can provide the same effect as imine because the dihydroimidazolidyl group exhibits high basicity.

When a terminal modifier such as dihydroimidazolidyl propyl triethoxy silane represented by Formula 2 reacts with the active terminal of the polymer, a mixture of addition reaction products with imine as represented by Formula 4 is produced.

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(b) The amount of the terminal modifier used in step (S200) is generally 0.25 to 3.0 moles, preferably 0.5 to 1.5 moles, based on 1 mole of an organo alkali metal used as an initiator for polymerization of the conjugated diene monomer. Less than 0.25 moles is undesirable because alkoxy groups are consumed due to the coupling reaction. On the other hand, when it exceeds 3 moles, the modifier is excessively present in the polymerization reaction system, and impurities contained in the modifier inactivate the anionic polymerization terminal, which is not preferable because the terminal modification rate is substantially reduced.

The reaction temperature between the terminal modifier and the lithium anion at the end of the polymer in step (b) may be the polymerization temperature of the diene polymer performed in step (a) (S100). Specifically, 30°C to 100°C is preferable. When it is lower than 30°C, the viscosity of the polymer tends to become too high, and when it exceeds 100°C, the terminal anion is easily deactivated, which is not preferable.

And the timing and method of adding the terminal modifier to the polymer in step (b) are not particularly limited, but in general, it is preferable that the modification reaction is performed after the polymerization reaction of the polymer is completed.

The chain end modifier formed in step (b) may be analyzed by high performance liquid chromatography (HPLC).

(b) When the nucleophilic substitution reaction is performed at the active end of the polymer in step (S200), an interaction occurs between the acidic functional group on the surface of the silica filler and the methylene amino group introduced by the modification reaction. Due to this, an excellent silica filler dispersing effect and a reinforcing effect are obtained. In this case, the filler dispersion effect and the reinforcing effect may occur simultaneously.

On the other hand, when an addition reaction occurs at the active end of the polymer, secondary amines are formed. Also in this case, since the secondary amine exhibits high hydrogen bonding with the silanol (Si-OH) group on the silica surface, excellent silica dispersibility effect can be obtained.

(b) In the modified conjugated diene-based polymer prepared through step (S200), the alkoxysilane group introduced to the end of the polymer by the terminal modifier is added as a filler through a hydrogen bonding force with a methylene amino group. Condensation reaction with a silanol group on the surface of the silica As this progresses, the dispersibility of silica can be further improved.

Then (c) step (S300) is a step of preparing a rubber composition by mixing the rubber component including the modified conjugated diene-based polymer prepared in (b) step (S200) and silica.

As the rubber component, a rubber component generally used in the tire industry may be used together with the modified conjugated diene-based polymer.

The rubber component is, for example, a styrene-butadiene copolymer (SBR), polybutadiene rubber (BR), polyisoprene rubber (IR), butyl rubber (IIR), and any one or more synthetic rubbers selected from ethylene-propylene copolymers, natural rubber, and mixtures thereof. Some of these rubber components may have a branched structure by using a modifier such as tin tetrachloride.

Based on the total weight of the rubber component, the modified conjugated diene-based polymer preferably contains 50% by weight or more. If the content of the modified conjugated diene-based polymer is less than 50% by weight, the content is small and the dispersibility of silica is poor.

Silica is used as a reinforcing filler in the rubber composition. The type of silica used in the present invention is not particularly limited, and examples thereof include wet silica (hydrated silicic acid) and dry silica (silicic anhydride), calcium silicate, aluminum silicate, etc., among others, the effect of improving fracture properties and Wet silica is most preferable because of its excellent wet braking properties and the effect of achieving low rolling resistance.

When silica is used alone in the rubber composition of the present invention, the silica content is preferably 38 wt% to 45 wt% based on the total rubber composition. If the silica content is 38 wt % or less, wet braking performance is not sufficient, and conversely, if it is 45 wt % or more, kneading of the composition becomes difficult due to a large amount of silica, making it difficult to obtain compounded rubber.

It is also possible to combine an appropriate amount of carbon black as a filler in addition to the above silica. The carbon black used herein is not particularly limited, and for example, FEF, SRF, HAF, ISAF, SAF, etc. may be used. Preferably, carbon black having an iodine adsorption amount (IA) of 60 mg/g or more and a dibutyl phthalate oil absorption amount (DBP) of 80 ml/100 g or more is preferable. By using carbon black, the effect of improving various physical properties of the rubber composition is increased, but HAF, ISAF and SAF having excellent abrasion resistance are particularly preferable.

When silica is used as a filler, a silane coupling agent may be used in compounding to further improve reinforcing properties, and bis(3-triethoxysilyl) may be preferably used. In view of the reinforcing effect, propyl tetrasulfide, 3-trimethoxysilyl propylbenzothiazole tetrasulfide and the like can be used.

Although the blending amount of the silane coupling agent varies depending on the type of the silane coupling agent, the blending amount of silica, etc., it is 1 wt% to 20 wt%, preferably 5 wt% to 15 wt%, from the viewpoint of reinforcing properties with respect to the blending amount of the silica.

Sulfur can be used as a vulcanizing agent in the rubber composition. The amount of these vulcanizing agents is preferably 0.1 to 10.0 parts by weight, more preferably 1.0 to 5.0 parts by weight as the sulfur content based on 100 parts by weight of the rubber component. If the amount of sulfur is less than 0.1 parts by weight based on 100 parts by weight of the rubber component, breaking strength, abrasion resistance and heat-resistant blowout performance deteriorate, and conversely, if it exceeds 10.0 parts by weight, rubber elasticity is lost.

Examples of process oils that can be used in the rubber composition include paraffinic, naphthenic and aromatic oils. Aromatic type process oils are used in applications where tensile strength and abrasion resistance are important, while naphthenic or paraffin types are used in applications where hysteresis loss and low temperature properties are important. The amount of the process oil used is preferably 0 to 100 parts by weight based on 100 parts by weight of the rubber component, and when the process oil content exceeds 100 parts by weight, the tensile strength and heat-resistant blowout performance of the rubber tends to deteriorate.

The vulcanization accelerator that can be used in the rubber composition is not particularly limited, but preferably diphenyl guanidine (DPG), 2-mercaptobenzothiazole (M), dibenzothiazyl disulfide (DM), N-cyclohexyl -2 (CZ) and other thiol-based vulcanization accelerators can be used. The amount of the vulcanization accelerator is preferably 1 part by weight to 5.0 parts by weight, more preferably 0.2 parts by weight to 3.0 parts by weight, based on 100 parts by weight of the rubber component.

In the rubber composition, in addition to the components presented above, additives such as antioxidants, zinc oxide, stearic acid, ethylene bisstearamide, antioxidants, and ozone-resistance inhibitors commonly used in the rubber industry may be additionally used. have.

(c) In step (S300), the rubber composition as described above is sufficiently mixed using a kneader such as a roll or an internal mixer to obtain it.

Due to the strong basicity of the terminal modifier of the modified conjugated diene-based polymer as in the rubber composition, a very fast hydrogen bonding effect with silica appears from the beginning of the mixing process, so that the polymer quickly covers the silica surface. Due to this effect, the modified conjugated diene-based polymer included in the rubber component exhibits excellent interaction even when preparing a silica rubber compound with a very high weight ratio, making it possible to ideally mix silica evenly dispersed. In the rubber composition according to the present invention, very excellent physical properties of heat generation, abrasion and wet braking properties can be realized.

After molding the rubber composition prepared through step (c) (S300), vulcanization may be performed to obtain tire tread, under tread, carcass, and sidewall.

The rubber composition is particularly preferably used as a rubber composition for tires such as sidewalls and beads, but may also be used for vibration damping rubber, belts, hoses and other industrial products.

Hereinafter, the present invention will be described in more detail through Preparation Examples, Comparative Examples, and Examples. The present invention is not limited to these descriptions unless the gist of the present invention is exceeded.

In this specification, parts and % mean parts by weight and % by weight unless otherwise specified, and unless otherwise specified, raw materials used for polymerization were dried and purified raw materials.

<Production Example 1>

Preparation Example 1 relates to the preparation of a polymer, cyclohexane (cyclohexane) 300 g, 1,3-butadiene (1,3-butadiene) monomer 32.5 g, styrene (styrene) monomer 17.5 g and ditetrahydrofuryl propane (2, 0.5 mmol of 2-Di(2-tetrahydrofuryl)propane) was placed in 800 ml of dry nitrogen substituted pressure-resistant glass vessel. After 0.55 mmol of n-butyl lithium (BuLi) was added, polymerization was performed at 50° C. for 1 hour. After the polymerization is completed, 0.5 ml of a 5% solution of 2,6-di-t-butyl paracresol (BHT) in isopropanol is added to stop the reaction without further terminal modification reaction, and the polymer whose reaction has been stopped is prepared in a conventional manner. and dried to obtain a polymer. At this time, the prepared polymer was named 'SBR-A'.

From the beginning to the end of polymerization in Preparation Example 1, the polymerization system was uniform and transparent without precipitation. At this time, the polymerization conversion was almost 100%.

<Production Example 2>

After 0.55 mmol of diethyl aminopropyl triethoxy silane was added as a terminal modifier to the polymer prepared in Preparation Example 1, a denaturation reaction was performed for 30 minutes. Thereafter, 0.5 ml of a 5% solution of 2,6-di-t-Butyl-p-cresol (BHT) in isopropanol was added to the polymerization system to stop the reaction, The polymer whose reaction was stopped was dried according to a conventional method to obtain a modified conjugated diene-based polymer, which was named 'SBR-B'.

<Production Example 3>

Preparation Example 3 is the same method as in Preparation Example 2, except that N-(1,3-dimethyl butylidene)-3-(triethoxy silyl)-1-propanamine (DMBTESPA) was used as a terminal modifier to prepare a modified conjugated diene-based polymer, which was named 'SBR-C'.

<Production Example 4>

In Preparation Example 4, a modified conjugated diene-based polymer was prepared in the same manner as in Preparation Example 2, except that dihydroimidazolidyl propyl triethoxy silane was used as a terminal modifier, which was named 'SBR-D'. did.

Using the polymers and modified conjugated diene-based polymers prepared in Preparation Examples 1 to 4, according to the composition of Compound 1 and Compound 2 shown in Table 1 below, the rubber compositions of Examples and Comparative Examples shown in Table 2 were prepared. prepared. Here, the unit of the content of the component described in Table 1 is expressed as phr (part per hundred rubber by weight) by weight based on 100 parts by weight of the rubber component.

division Compound 1
(phr) Compound 2
(phr) SBR 100 100 silica 55 110 process oil 10 40 6-PPD One One WAX One One stearic acid One One Zinc Oxide (ZnO) 2 2 DPG 1.5 1.5 DM 1.5 1.5 NS 1.5 1.5 S 1.5 1.5

In Table 1, silica is Nipsil AQ (Toso Silica Co., Ltd., Japan), and the coupling agent is Si69 (bis (3-triethoxy silyl propyl) tetrasulfide (bis [3- ( triethoxysilyl)propyl]tetrasulfide) was used.

And in Table 1, DM is mercapto benzothiazyl disulfide, NS is N-t-butyl-2-benzothiazyl sulfenamide, DPG is diphenyl guanidine, and S is sulfur.

In order to evaluate the physical properties of the rubber compositions of Comparative Examples and Examples prepared according to the composition of Table 1, the physical properties of the following items were evaluated, and the results are shown in Table 2.

Specifically, the rubber composition was evaluated for rolling resistance (RR), braking characteristics (wet grip), low heat generation, fracture characteristics, and abrasion resistance (ear resistance) as physical properties of the rubber composition through a rubber specimen prepared by vulcanization.

The low exothermic index uses a tan δ value measured at a temperature of 50° C., a strain of 5% and a frequency of 15 Hz using a viscoelasticity measuring device of Rheometrics Inc. The higher the hypothermic index, the smaller the Tan δ.

Wet grip was measured using a Stanley London type portable skid tester. Results are displayed as an index with the control set to 100. The larger the index, the better the performance.

For fracture properties, tensile strength at break (Tb), elongation at break (Eb) and tensile stress at 300% elongation (M300) were measured according to JIS K6301-1995, a JIS standard.

Abrasion resistance was measured using a Lambourn wear tester at room temperature at a slip ratio of 60%, and the wear resistance of the control group was set to 100 to indicate the wear resistance index. Here, the higher the abrasion resistance index, the better.

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Example 1 Example 2 modified SBR SBR-A SBR-B SBR-C SBR-D SBR-A SBR-B SBR-C SBR-D Compound One One One One 2 2 2 2 silica
(weight%) 31.4 31.4 31.4 31.4 42.1 42.1 42.1 42.1 cloud resistance 100 105 118 120 90 94 118 120 brakeability 100 100 102 99 115 115 118 118 wear resistance 100 110 115 120 90 98 110 110

As shown in Table 2, when the modified conjugated diene-based polymer was used, it was confirmed that the physical properties were improved even in Comparative Examples 2, 3, 4, and 6 in which a relatively small amount of silica was blended. .

However, as shown in Examples 1 and 2, when the silica content was 38% by weight and 42.1% by weight was included, it was confirmed that the improvement effect of these properties was superior to those of Comparative Examples 1 to 6, It can be seen that by the combination of Examples 1 and 2, a rubber composition having excellent physical properties such as rolling resistance, braking property, and abrasion resistance can be obtained.

Claims (15)

a rubber component comprising a modified conjugated diene-based polymer represented by the following Chemical Formula 4 in which a modifier is introduced at the active end of the polymer as a terminal modifier represented by the following Chemical Formulas 1 and 2; and
Silica as a reinforcing filler; including,
Based on the total weight of the rubber component, the modified conjugated diene-based polymer comprises 50% by weight or more,
Based on the total weight of the rubber composition, the silica is a rubber composition, characterized in that it comprises 38% to 45% by weight.
[Formula 1]

(In Formula 1, R ₁ is a methyl group, R ₂ is an isobutyl group)
[Formula 2]

[Formula 4]

(In Formula 4, Polymer is a conjugated diene-based polymer chain, in Formula 4, R ₁ is a methyl group, and R ₂ is an isobutyl group) delete delete delete delete According to claim 1,
The rubber component is a styrene-butadiene copolymer, polybutadiene rubber, polyisoprene rubber, butyl rubber, and at least one synthetic rubber selected from among ethylene-propylene copolymer, natural rubber, and a mixture thereof. Rubber composition. According to claim 1,
The rubber composition, characterized in that it comprises at least one selected from carbon black, silane coupling agent, process oil, vulcanization accelerator, zinc oxide, stearic acid, antioxidant, and ozone degradation inhibitor as an additive. (a) polymerizing a conjugated diene-based monomer and a vinyl aromatic monomer using a hydrocarbon lithium compound having 2 to 20 carbon atoms as a polymerization initiator in a hydrocarbon solvent to form a polymer having an active terminal;
(b) preparing a modified conjugated diene-based polymer represented by the following Chemical Formula 4 by introducing a modifying group at the active end of the polymer with a terminal modifier represented by the following Chemical Formula 1 or Chemical Formula 2;
(c) preparing a rubber composition by mixing a rubber component including the modified conjugated diene-based polymer and silica;
Based on the total weight of the rubber component in step (c), the modified conjugated diene-based polymer comprises 50% by weight or more,
Based on the total weight of the rubber composition, the rubber composition manufacturing method, characterized in that for preparing the rubber composition to include 38 wt% to 45 wt% of the silica.
[Formula 1]

(In Formula 1, R ₁ is a methyl group, R ₂ is an isobutyl group)
[Formula 2]

[Formula 4]

(In Formula 4, Polymer is a conjugated diene-based polymer chain, in Formula 4, R ₁ is a methyl group, and R ₂ is an isobutyl group) delete delete delete delete delete 9. The method of claim 8,
The rubber component is a styrene-butadiene copolymer, polybutadiene rubber, polyisoprene rubber, butyl rubber, and at least one synthetic rubber selected from among ethylene-propylene copolymer, natural rubber, and a mixture thereof. Rubber A method for preparing a composition. 9. The method of claim 8,
The rubber composition comprises at least one selected from carbon black, silane coupling agent, process oil, vulcanization accelerator, zinc oxide, stearic acid, antioxidant, and ozone degradation inhibitor as an additive.

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