KR102159324B1 - Rubber composition for tire sidewall and Tire comprising same - Google Patents

Abstract

Provided are a rubber composition for a tire sidewall and a tire made of the composition, wherein the rubber composition includes natural rubber and butadiene rubber, wherein the butadiene rubber includes a cis double bond, a trans double bond and a vinyl group, and there are more trans double bonds than cis double bonds. Tires made with the rubber composition for sidewalls according to an embodiment of the present invention show superior fuel efficiency than tires made with a general sidewall rubber composition.

Description

Rubber composition for tire sidewall and tire comprising the same

It relates to a rubber composition for a tire sidewall and a tire including the same.

With the growing interest in environmental issues around the world, the demand for environmentally friendly products from everyday life products to industrial products is increasing.

One aspect of this trend is to improve the fuel economy of automobiles. In order to improve the fuel efficiency of automobiles, in addition to the development demand for the automobile itself, the demand for fuel efficiency improvement of tires essential for automobiles continues as well.

In general, tires are largely composed of a tread, a sidewall, and a bead, and in particular, in order to improve the low fuel consumption performance, the tire is generally designed and applied to have the low hysteresis characteristics of the tread compound.

One aspect is to provide a rubber composition for side walls that improves fuel efficiency by lowering the hysteresis of the sidewall compound of a tire.

Another aspect is to provide a tire made of the rubber composition.

According to one aspect,

Including natural rubber and butadiene rubber,

The butadiene rubber contains a cis double bond, a trans double bond and a vinyl group,

The trans double bond is present more than the cis double bond

A rubber composition for a tire sidewall is provided.

According to the other side,

A tire made of the rubber composition is provided.

Tires made with the rubber composition for sidewalls according to an embodiment of the present invention show superior fuel economy than tires made with a general sidewall rubber composition.

1 is a view schematically showing the structure of a tire according to an embodiment.
2 is a diagram schematically showing a general structure of a butadiene rubber.

Hereinafter, a rubber composition for a tire sidewall and a tire including the same will be described in more detail in an exemplary embodiment.

Since the inventive idea disclosed in the present specification can apply various transformations and have various implementations, specific implementations are described in detail in the detailed description, and when necessary, specific implementations are illustrated in the drawings. Effects and features of the creative ideas of the present specification, and a method of achieving them will become apparent with reference to implementation examples described below in detail together with the drawings. However, the creative idea of the present specification is not limited to the embodiments disclosed below, but may be implemented in various forms.

In the following embodiments, terms such as first and second are not used in a limiting meaning, but are used for the purpose of distinguishing one component from another component.

In the following embodiments, a singular expression includes a plural expression unless the context clearly indicates otherwise.

In the following embodiments, terms such as include or have means that the features or elements described in the specification are present, and do not preclude the possibility of adding one or more other features or elements in advance.

When one embodiment can be implemented differently, a specific process order may be performed differently from the described order. For example, two processes described in succession may be performed substantially simultaneously, or may be performed in an order opposite to the described order.

Hereinafter, if necessary, embodiments of the present invention will be described in detail with reference to the accompanying drawings, and when describing with reference to the drawings, identical or corresponding components are given the same reference numerals, and redundant descriptions thereof will be omitted. To

In the drawings, components may be exaggerated or reduced in size for convenience of description. For example, the size and thickness of each component shown in the drawings are arbitrarily shown for convenience of description, and thus the creative ideas disclosed in the present specification are not necessarily limited to those shown.

Referring to FIG. 1, the tire 10 includes a tread part 100, a sidewall part 200, and a bead part 300.

The tread portion 100 is a portion in contact with the ground in cross section, and serves to protect the tire from impact and trauma from the road surface. A plurality of blocks partitioned by grooves may be formed on the surface of the tread portion as described above to improve the drainage characteristics of the tire.

The sidewall 200 and the bead part 300 are sequentially positioned on both sides along the width direction of the tire with the tread part as the center.

The sidewall 200 is a part that extends from both ends of the tread to form the side of the tire, withstands continuously repeated contraction and expansion during driving, and protects the carcass layer 400 located on the inner surface. Do it.

The rubber composition for a tire sidewall according to an embodiment of the present invention includes natural rubber and butadiene rubber, and the butadiene rubber includes a cis double bond, a trans double bond, and a vinyl group, and the trans double bond is more than the cis double bond. There are many.

2 is a diagram schematically showing a general structure of a butadiene rubber.

Butadiene rubber is a polymer in which a monomer, 1,3-butadiene, is polymerized by a catalyst. Catalysts used in the polymerization of butadiene rubber include nickel, neodynium, cobalt, titanium, butyl lithium, and the like, and can be classified into solution polymerization and emulsion polymerization depending on the reaction system.

The polymerized butadiene rubber has double bonds in the chain, and there are cases where the form of the double bond is cis or trans.

)가 시스 이중 결합이고, 두번째 괄호에 있는 단위(

)가 트랜스 이중 결합 부분이다. 마지막 괄호 부분은 비닐기가 펜던트로 달려있는 것(

)을 나타낸다.2, the unit in the first parenthesis ([ ]) (

) Is a cis double bond, and the unit in the second parenthesis (

) Is the trans double bond moiety. The last part in parentheses is a vinyl group attached to the pendant (

).

On the other hand, when nickel, neodynium, cobalt, or titanium is used as a catalyst in the solution polymerization system, the content of cis double bonds increases, and when the emulsion polymerization system is used, the content of trans double bonds increases.

When butyl lithium is used as a catalyst, a butyl rubber having a trans double bond content greater than the cis double bond content can be obtained.

When the catalyst is Ti, it is polymerized at 5 to 35°C through a Ziegler-Natta catalyst in a solvent benzene or toluene.

When the catalyst is Co, it is polymerized in a solvent benzene or toluene with diethylaluminum-chloride or Et ₃ Al ₂ Cl ₃ with CoCl ₂ or Co-(octenate) ₂ at 5 to 35°C. .

When the catalyst is Ni, it is polymerized at 50 to 60°C in an aliphatic or cycloaliphatic solvent with Ni (naphtanate) ₂ /BF ₃ derivative.

When the catalyst is Nd, the carboxylate of Nd in a cycloaliphatic solvent; Lewis acid Et ₃ Al ₂ Cl ₃ ; Al-alkyl compounds such as Et ₃ Al, i-Bu ₃ Al, and i-Bu ₂ AlH are polymerized at 0 to 60°C. As the temperature increases, the cis content increases and the molecular weight decreases.

When the catalyst is Li, anionic polymerization is performed using n-Bu-Li or s-Bu-Li as an initiator, and a narrow molecular weight distribution is shown. The cis-trans-vinyl content is highly dependent on the polarity of the solvent, and the reaction temperature is about 50 to 80°C.

According to one embodiment of the present invention, the butadiene rubber of the rubber composition for the tire sidewall may contain 15% to 55% of the cis double bond.

According to one embodiment of the present invention, the butadiene rubber of the rubber composition for the tire sidewall may contain 35% to 75% of the trans double bond.

According to one embodiment of the present invention, the butadiene rubber of the rubber composition for the tire sidewall may contain 5% to 15% of the vinyl group.

According to an embodiment of the present invention, the butadiene rubber of the rubber composition for the tire sidewall contains 25% to 45% of the cis double bond, 45% to 65% of the trans double bond, and 6% to 14% of vinyl groups. I can. In FIG. 2, values of l, m, and n are values corresponding to the% values.

When the content ratio of the cis double bond, trans double bond, and vinyl group of the butadiene rubber is within the above range, the RR (rolling resistance) value of the rubber composition for tire sidewall shows excellent results.

The natural rubber may be a general natural rubber or a modified natural rubber.

The general natural rubber may be used as long as it is known as natural rubber, and the country of origin is not limited. The natural rubber mainly contains cis-1,4-polyisoprene, but may also contain trans-1,4-polyisoprene depending on the required properties. Therefore, in addition to natural rubber containing cis-1,4-polyisoprene as a main body, the natural rubber includes trans-1,4-isoprene as a main body, such as Valata, a kind of rubber of the Sapota family from South America. It may also contain rubber.

The modified natural rubber means that the general natural rubber is modified or purified. For example, examples of the modified natural rubber include epoxidized natural rubber (ENR), deproteinized natural rubber (DPNR), and hydrogenated natural rubber.

According to one embodiment of the present invention, the rubber composition may include other synthetic rubbers in addition to butadiene rubber as raw rubber.

The synthetic rubber may include at least one selected from styrene butadiene rubber (SBR), isoprene-containing styrene butadiene rubber, nitrile-containing styrene butadiene rubber, neoprene rubber, chlorobutyl rubber, and bromobutyl rubber.

According to one embodiment of the present invention, the rubber composition may include 40 to 80 parts by weight of the natural rubber and 10 to 60 parts by weight of the butadiene rubber as raw rubber. The butadiene rubber may be a rubber made of butyl lithium as a catalyst.

According to one embodiment of the present invention, the rubber composition may further include a high cis-butadiene rubber containing 90% to 98% of a cis double bond. In this case, the natural rubber is 40 to 80 parts by weight, the butadiene rubber is 20 to 30 parts by weight, and the gocis-butadiene rubber may be included in 10 to 20 parts by weight.

When the content of natural rubber and butadiene rubber is within the above range, processability and physical properties of vulcanized rubber are optimal.

According to one embodiment of the present invention, the sidewall rubber composition may include a filler, and may include, for example, carbon black.

The carbon black may have a nitrogen surface area per gram (N ₂ SA) of 30 to 300 m ² /g, and an oil absorption of DBP (n-dibutyl phthalate) may be 60 to 180 cc/100 g, but the present invention This is not limited to this.

When the nitrogen adsorption specific surface area of the carbon black exceeds 300 m ² /g, the processability of the rubber composition for tires may be disadvantageous, and when it is less than 30 m ² /g, the reinforcing performance by carbon black as a filler may be disadvantageous. In addition, when the DBP oil absorption amount of the carbon black exceeds 180cc/100g, the processability of the rubber composition may be deteriorated, and when it is less than 60cc/100g, the reinforcing performance by carbon black as a filler may be disadvantageous.

Representative examples of the carbon black include N110, N121, N134, N220, N231, N234, N242, N293, N299, S315, N326, N330, N332, N339, N343, N347, N351, N358, N375, N539, N550, N582 , N630, N642, N650, N683, N754, N762, N765, N774, N787, N907, N908, N990, N991, and the like.

According to an embodiment of the present invention, the carbon black may be N660.

According to one embodiment of the present invention, the carbon black content may be 40 to 55 parts by weight based on 100 parts by weight of the rubber composition. If the content of the carbon black is less than 40 parts by weight, the strength may not be satisfactory, and if it exceeds 55 parts by weight, the processability of the rubber composition may be disadvantageous.

The sidewall composition may optionally further include various additives such as an additional vulcanization agent, a vulcanization accelerator, a vulcanization accelerator, an anti-aging agent, an antioxidant, or a softener. The various additives may be used as long as they are commonly used in the field to which the present invention pertains, and their content is not particularly limited as a bar depending on the blending ratio used in a typical tire belt rubber composition.

As the curing agent, a sulfur-based curing agent may be preferably used. The sulfur-based vulcanizing agents include inorganic vulcanizing agents such as powdered sulfur (S), insoluble sulfur (S), precipitated sulfur (S), and colloidal sulfur, and tetramethylthiuram disulfide (TMTD), tetraethyl Organic vulcanizing agents, such as tetraethyltriuram disulfide (TETD) and dithiodimorpholine, may be used. As the sulfur vulcanizing agent, specifically elemental sulfur or a vulcanizing agent that produces sulfur, for example, amine disulfide, polymer sulfur, or the like may be used.

It is preferable that the vulcanizing agent be included in an amount of 0.5 to 10.0 parts by weight based on 100 parts by weight of the raw rubber, as an appropriate vulcanizing effect, and it is preferable that the raw rubber is less sensitive to heat and chemically stable.

The vulcanization accelerator refers to an accelerator that accelerates the vulcanization rate or accelerates the delaying action in the initial vulcanization step.

The vulcanization accelerators include sulfenamide-based, thiazole-based, thiuram-based, thiourea-based, guanidine-based, dithiocarbamic acid-based, aldehyde-amine-based, aldehyde-ammonia-based, imidazoline-based, xanthate-based, and these Any one selected from the group consisting of combinations can be used.

Examples of the sulfenamide-based vulcanization accelerator include N-cyclohexyl-2-benzothiazylsulfenamide (CBS), N-tert-butyl-2-benzothiazylsulfenamide (TBBS), and N,N-dicyclohexyl Any one selected from the group consisting of -2-benzothiazylsulfenamide, N-oxydiethylene-2-benzothiazylsulfenamide, N,N-diisopropyl-2-benzothiazolesulfenamide, and combinations thereof Sulfenamide-based compounds of can be used.

Examples of the thiazole-based vulcanization accelerator include 2-mercaptobenzothiazole (MBT), dibenzothiazyl disulfide (MBTS), sodium salt of 2-mercaptobenzothiazole, zinc salt of 2-mercaptobenzothiazole , Copper salt of 2-mercaptobenzothiazole, cyclohexylamine salt of 2-mercaptobenzothiazole, 2-(2,4-dinitrophenyl)mercaptobenzothiazole, 2-(2,6-di Ethyl 4-morpholinothio) benzothiazole and any one thiazole-based compound selected from the group consisting of combinations thereof may be used.

Examples of the thiuram-based vulcanization accelerator include tetramethylthiuram disulfide (TMTD), tetraethylthiuram disulfide, tetramethylthiuram monosulfide, dipentamethylenethiuram disulfide, dipentamethylenethiurammonosulfide, dipentamethylene Thiuram tetrasulfide, dipentamethylene thiuram hexasulfide, tetrabutyl thiuram disulfide, pentamethylene thiuram tetrasulfide, and any one thiuram-based compound selected from the group consisting of a combination thereof may be used.

As the thiourea-based curing accelerator, for example, any one thiourea-based selected from the group consisting of thiacarbamide, diethylthiourea, dibutylthiourea, trimethylthiourea, diorthotolylthiourea, and combinations thereof Compounds can be used.

As the guanidine-based vulcanization accelerator, for example, any one guanidine-based compound selected from the group consisting of diphenylguanidine, diorthotolylguanidine, triphenylguanidine, orthotolylbiguanide, diphenylguanidine phthalate, and combinations thereof can be used. I can.

Examples of the dithiocarbamic acid-based vulcanization accelerator include zinc ethylphenyldithiocarbamate, zinc butylphenyldithiocarbamate, sodium dimethyldithiocarbamate, zinc dimethyldithiocarbamate, zinc diethyldithiocarbamate, Zinc dibutyldithiocarbamate, zinc diamyldithiocarbamate, zinc dipropyldithiocarbamate, complex salt of zinc pentamethylenedithiocarbamate and piperidine, zinc hexadecylisopropyldithiocarbamate, octadecyl Zinc isopropyldithiocarbamate, zinc dibenzyldithiocarbamate, sodium diethyldithiocarbamate, piperidine pentamethylenedithiocarbamate, selenium dimethyldithiocarbamate, tellurium diethyldithiocarbamate, dia Any one dithiocarbamic acid-based compound selected from the group consisting of cadmium mildithiocarbamate and combinations thereof may be used.

The aldehyde-amine-based or aldehyde-ammonia-based vulcanization accelerator is, for example, an aldehyde selected from the group consisting of acetaldehyde-aniline reactant, butylaldehyde-aniline condensate, hexamethylenetetramine, acetaldehyde-ammonia reactant, and combinations thereof. -Amine-based or aldehyde-ammonia-based compounds can be used.

As the imidazoline-based vulcanization accelerator, an imidazoline-based compound such as 2-mercaptoimidazoline may be used. As the xanthate-based vulcanization accelerator, for example, xanthate-based zinc dibutyl xanthogenate Compounds can be used.

The vulcanization accelerator may be included in an amount of 0.5 to 4.0 parts by weight based on 100 parts by weight of the raw rubber in order to maximize productivity and rubber properties through acceleration of a vulcanization rate.

The vulcanization accelerator aid is a blending agent used in combination with the vulcanization accelerator to complete its accelerating effect, and any one selected from the group consisting of inorganic vulcanization accelerators, organic vulcanization accelerators, and combinations thereof may be used. .

As the inorganic vulcanization accelerator, any one selected from the group consisting of zinc oxide (ZnO), zinc carbonate, magnesium oxide (MgO), lead oxide, potassium hydroxide, and combinations thereof can be used. have. The organic vulcanization accelerator is selected from the group consisting of stearic acid, zinc stearate, palmitic acid, linoleic acid, oleic acid, lauric acid, dibutyl ammonium oleate, derivatives thereof, and combinations thereof. You can use either.

In particular, the zinc oxide and the stearic acid may be used together as the vulcanization accelerator, and in this case, the zinc oxide is dissolved in the stearic acid to form an effective complex with the vulcanization accelerator, thereby reducing advantageous sulfur during the vulcanization reaction. It facilitates crosslinking reaction of rubber by making it.

When the zinc oxide and the stearic acid are used together, it may be used in an amount of 1 to 10 parts by weight and 0.5 to 3 parts by weight based on 100 parts by weight of the raw rubber, respectively, to serve as an appropriate vulcanization accelerator. When the content of the zinc oxide and the stearic acid is less than the above range, the vulcanization rate may be slow and productivity may be lowered. When the content of the zinc oxide and the stearic acid is less than the above range, a scorch phenomenon may occur and physical properties may decrease.

The softening agent is added to the rubber composition to facilitate processing by imparting plasticity to the rubber or to reduce the hardness of the vulcanized rubber, and refers to oils and other materials used during rubber compounding or rubber production. The softener means process oil or oils included in other rubber compositions. As the softener, any one selected from the group consisting of petroleum oils, vegetable oils, and combinations thereof may be used, but the present invention is not limited thereto.

As the petroleum oil, any one selected from the group consisting of paraffinic oil, naphthenic oil, aromatic oil, and combinations thereof may be used.

Representative examples of the paraffinic oil include P-1, P-2, P-3, P-4, P-5, and P-6 of Michang Oil Co., Ltd., and representative examples of the naphthenic oil are Michang Oil N-1, N-2, and N-3 of Co., Ltd. may be mentioned, and representative examples of the aromatic oil include A-2 and A-3 of Michang Oil Co., Ltd.

However, it is known that cancer-causing potential is high when the content of polycyclic aromatic hydrocarbons (hereinafter referred to as PAHs) contained in the aromatic oil is 3% by weight or more, along with the recent increase in environmental awareness, TDAE ( Treated distillate aromatic extract) oil, MES (mild extraction solvate) oil, RAE (residual aromatic extract) oil, or heavy naphthenic oil may be preferably used.

In particular, the oil used as the softener has a total content of PAHs of 3% by weight or less with respect to the entire oil, a kinematic viscosity of 95 or more (210°F SUS), an aromatic component in the softener of 15 to 25% by weight, and a naphthenic component TDAE oil having 27 to 37% by weight and 38 to 58% by weight of the paraffinic component can be preferably used.

The TDAE oil is advantageous in terms of environmental factors such as cancer-causing potential of PAHs while improving low-temperature characteristics and fuel economy performance of tires including the TDAE oil.

The plant oils include castor oil, cottonseed oil, linseed oil, canola oil, soybean oil, palm oil, palm oil, peanut oil, pine oil, pine tar, tall oil, corn oil, rice bran oil, safflower oil, sesame oil, olive oil, sunflower oil, palm kernel oil, camellia oil , Jojoba oil, macadamia nut oil, saflower oil, tung oil, and any one selected from the group consisting of a combination thereof may be used.

The softener is preferably used in an amount of 0 to 10 parts by weight based on 100 parts by weight of the raw rubber in that it improves the processability of the raw rubber.

The anti-aging agent is an additive used to stop a chain reaction in which the tire is automatically oxidized by oxygen. As the anti-aging agent, any one selected from the group consisting of amine-based, phenol-based, quinoline-based, imidazole-based, carbamic acid metal salts, waxes, and combinations thereof may be appropriately selected and used.

Examples of the amine-based antiaging agent include N-phenyl-N'-(1,3-dimethyl)-p-phenylenediamine, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine, N-phenyl-N'-isopropyl-p-phenylenediamine, N,N'-diphenyl-p-phenylenediamine, N,N'-diaryl-p-phenylenediamine, N-phenyl-N' -Any one selected from the group consisting of cyclohexyl p-phenylenediamine, N-phenyl-N'-octyl-p-phenylenediamine, and combinations thereof may be used. The phenolic antioxidants include phenolic 2,2'-methylene-bis(4-methyl-6-tert-butylphenol), 2,2'-isobutylidene-bis(4,6-dimethylphenol), 2 ,6-di-t-butyl-p-cresol, and any one selected from the group consisting of combinations thereof may be used. As the quinoline-based antioxidant, 2,2,4-trimethyl-1,2-dihydroquinoline and derivatives thereof may be used, and specifically 6-ethoxy-2,2,4-trimethyl-1,2-di Consisting of hydroquinoline, 6-anilino-2,2,4-trimethyl-1,2-dihydroquinoline, 6-dodecyl-2,2,4-trimethyl-1,2-dihydroquinoline and combinations thereof Any one selected from the group can be used. Preferably, waxy hydrocarbon may be used as the wax.

In addition to the anti-aging action, the anti-aging agent must have a high solubility in rubber, low volatility and inert to rubber, and not inhibit vulcanization, etc., 1 to 10 parts by weight of the raw rubber. It may be included in parts by weight.

A typical amount of the antioxidant may be included, for example, in about 1 to about 5 parts by weight. Representative antioxidants are, for example, diphenyl-p-phenylenediamine and others, but are not limited thereto.

Meanwhile, the bead portion 300 is provided at both ends of the sidewall 200 to surround the end of the cord paper, and the bead portion 300 includes a bead core 500 including a ring-shaped steel wire.

A carcass layer 400 is positioned between the pair of left and right bead portions 300, and is bonded to the tire rubber sheet inside the tire to form the skeleton of the tire, and the carcass layer 400 is the bead core 500 ) It is rolling up from the inside of the tire to the outside.

An inner liner 700 is located on one side of the inner side of the carcass layer 400 and serves to prevent air inside the tire from escaping to the outside.

The belt layer 600 may be positioned on the outer surface of the carcass layer 400 positioned on the tread portion 100 as a reinforcing layer that increases the elasticity of the tread and has maneuverability and stability.

A cap ply 800 including a hybrid cord may be disposed between the belt layer 600 and the tread portion 100. The cap ply 800 may suppress the flow of the belt layer 600 during driving to maintain the performance of the tire.

The sidewall composition may be prepared through a conventional two-step continuous manufacturing process. That is, during the first step of thermomechanical treatment or kneading at a maximum temperature ranging from 140 to 170°C, preferably at a high temperature of 150 to 160°C and the finishing step in which the crosslinking system is mixed, typically less than 110°C, for example It may be prepared in a suitable mixer using the second step of mechanical treatment at a low temperature of 80 to 100°C, but is not limited thereto.

Tire according to another embodiment of the present invention includes the step of using the rubber composition for the side wall when forming a green tire. The method of forming a green tire using the sidewall rubber composition may be applied to any method used in conventional tire manufacturing, and a detailed description thereof will be omitted herein.

1 illustrates a tire for a passenger car, but is not limited thereto, and may be a tire for a passenger car, a tire for a race, an airplane tire, a tire for agricultural machinery, an off-the-road tire, a truck tire, a bus tire, etc. have. In addition, the tire may be a radial tire or a bias tire, preferably a radial tire.

The present invention will be described in more detail through the following examples and comparative examples. However, the examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

Comparative example 1, 2 and Example 1 to 3

The composition shown in Table 1 was added to the Banbari mixer to mix the rubber compositions of Examples and Comparative Examples.

division Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Natural rubber 60 60 60 60 60 Butadiene rubber A ¹⁾ 40 - - 10 20 B ²⁾ - - 40 30 20 C ³⁾ - 40 - - - Carbon black ^{4 )} 38 38 38 38 38 Stearic acid 1.5 1.5 1.5 1.5 1.5 Zinc oxide 3 3 3 3 3 Wax ^{5 )} 2 2 2 2 2 sulfur 2 2 2 2 2 Accelerator ^{6 )} 0.75 0.75 0.75 0.75 0.75

1) more than 96% cis content

2) cis content 35%, trans content 55%, vinyl content 10%

3) 72% trans content,

4) Carbon Black: N660

5) PARAFFINE WAX

6) N-TERTIARYBUTYL-2-BENZOTHIAZOLE-SULFENAMIDE

Evaluation example

<Basic property evaluation>

The specimens prepared in Comparative Examples 1 and 2 and Examples 1 to 3 were prepared in a vulcanizer at 165° C. for 10 minutes, and basic physical properties were evaluated for the vulcanized specimens as follows, and the results are shown in Table 2 below. Shown in.

HD(hardness)

According to ASTM D2240-97, a single specimen was measured five times on a smooth surface with a thickness of 6 mm or more and a diameter of 10 mm or more using a Shore A type hardness tester, and the average value was determined.

Tensile properties

The measurement of the tensile strength of the crosslinked specimen was conducted according to ASTM D412 using a tensile tester (INSTRON). The specimen for measurement was manufactured in a sheet form using a hydraulic press and a dumbbell type using a specimen cutter. Test conditions were measured at room temperature at a tensile speed of 500 mm/min. Tensile strength (T/S) is a value representing the stress value until the test piece is broken in a tensile tester, and the force received per unit area was measured.

M-300 is a value representing the stress value at 300% elongation in a tensile tester, and the force received per unit area was measured.

Elongation

It is a value showing the strain value (strain rate) until the test piece breaks in the tensile tester.

Viscoelasticity (Dynamic Properties)

The viscoelasticity was measured for tanδ values from -80°C to 70°C under 10Hz frequency at 0.2% strain using a Gabo viscometer measuring device. At this time, the temperature having the highest tanδ value is defined as the glass transition temperature, and the smaller the tanδ value at 60°C, the less heat generated during driving and the greater the rotational resistance.

Comparative example One Comparative example 2 Example One Example 2 Example 3 HD[hardness] 56 62 56 56 56 M-300(kgf/cm ² ) 73 95 74 74 73 Tensile strength (kgf/cm ² ) 188 120 210 200 190 Elongation(%) 570 350 600 590 580 Tanδ @ 60℃ (index) 0.097(100) 0.120(81) 0.083(117) 0.087(112) 0.092(105)

Referring to Table 2, it can be seen that tan δ values at 60° C. of Examples 1 to 3 in the vulcanized rubber properties are lower than those of Comparative Examples 1 and 2. Therefore, it can be seen that the viscoelasticity of the vulcanized rubber of the rubber composition for a tire sidewall according to an embodiment of the present invention is superior to that of the comparative example.

<Tire evaluation>

Tires (standard: 205/60R16) were prepared with the rubber compositions prepared in Comparative Examples 1 and 2 and Examples 1 to 3 to evaluate RR (Rolling Resistance) and durability (DOT 139 End), and the results are shown in Table 3 below. Shown in.

Rolling Resistance (RR)

Rolling resistance, which is a tire factor of vehicle fuel economy, is energy consumed per unit mileage, and the unit is N (N-m/m). The test is to measure the rolling resistance under normal inflation conditions, that is, the tire inflates and creates inflation pressure.

DOT 139 End

DOT 139 End evaluation is an evaluation method in which 180kpa air pressure is put in, the load is increased to 85% to 120% depending on the driving time, and after 34 hours, the air pressure is lowered to 140kpa to run and the tire breakage time is measured. The higher the time, the higher the durability of the tire.

Comparative example One Comparative example 2 Example One Example 2 Example 3 RR (index) 100 96 102 102 101 DOT 139 End (time) 123 60 162 143 131

As can be seen from Table 3, it can be seen that the tires of Examples 1 to 3 have better fuel economy and superior durability than those of Comparative Examples 1 and 2.

10: tire
100: tread
200: side wall part
300: bead part
400: carcass layer
500: bead core
600: belt layer
700: inner liner

Claims (10)

Including natural rubber, butadiene rubber and carbon black,
The butadiene rubber contains a cis double bond, a trans double bond and a vinyl group,
The cis double bond content of the butadiene rubber is 25% to 45%, the trans double bond content is 45% to 65%, the vinyl group content is 6% to 14%,
The butadiene rubber is a rubber made of butyl lithium as a catalyst,
The carbon black is N660,
Rubber composition for tire sidewall. delete delete delete delete The method of claim 1,
The natural rubber is 40 to 80 parts by weight, the butadiene rubber is 10 to 60 parts by weight of a rubber composition for a tire sidewall. The method of claim 1,
The rubber composition for a tire sidewall further comprises a gocis-butadiene rubber containing 90% to 98% of the cis double bond. The method of claim 7,
The natural rubber is 40 to 80 parts by weight, the butadiene rubber is 20 to 30 parts by weight, and the gocis-butadiene rubber is 10 to 20 parts by weight of a rubber composition for a tire sidewall. delete A tire made of the rubber composition for a tire sidewall of claim 1.

Images