Tire rubber composition for summer and vehicle tire using same

Abstract

The present invention relates to a rubber composition for a tire and a vehicle tire using same and, more specifically, to: a rubber composition for a tire, which is suitable for high-temperature and high-humidity summer weather, has excellent wear resistance and rolling resistance, and has improved grip force on a wet road surface; and a pneumatic tire for a vehicle using same.

Description

Summer tire rubber composition and vehicle tire using the same

[0001] The present invention relates to a rubber composition for a tire and a vehicle tire using the same, and more particularly, to a rubber composition for a tire that is suitable for high temperature and humid summer weather, has excellent wear resistance and rolling resistance, and has improved grip on wet roads, and to a pneumatic tire for a vehicle using the same.

[0002] In the tire industry, extensive research is being conducted to simultaneously improve mechanical properties and fuel efficiency. Conventional rubber compositions typically utilize elastomeric polymers such as natural rubber, polybutadiene, polyisoprene, and polystyrene butadiene rubber, and typically incorporate reinforcing fillers to enhance the rubber's mechanical properties.

[0003] Carbon black has been the most popular choice in the past due to its characteristics such as surface affinity with rubber, high specific surface area, and developed structure. However, recently, there has been a trend to use silica instead of carbon black for lower rolling resistance and superior wet grip performance.

[0004] In fact, using silica as a filler in tread compounds, along with a silane coupling agent, can reduce fuel consumption by approximately 3-4% and provide improved wet grip compared to tires with carbon black treads. However, conventional silica is manufactured from sand and extracted from specific minerals such as silica or silica sand. Therefore, there is concern that natural resources will be depleted in the future, requiring replacement with sustainable raw materials.

[0005] In addition, although conventional technologies have attempted various methods to simultaneously improve the mechanical properties, wear resistance, and rolling resistance of rubber compositions, it is a technical challenge to provide excellent tread wear resistance performance while also providing excellent wet grip performance and low rolling resistance.

[0006] In general, a tire's wear performance, wet grip, and rolling resistance are in a trade-off relationship, so improving wear resistance generally comes with a trade-off of reduced wet grip performance.

[0007] Therefore, the development of technologies capable of simultaneously improving wet grip performance and mechanical properties is necessary. While hydrocarbon polymer additives with higher glass transition temperatures than the rubber composition are sometimes added to improve wet grip performance, there are still limitations that make it difficult to technically overcome this trade-off.

[0008] As a prior art, Korean Patent Publication No. 2010-0058727 proposes mixing silica and general-purpose carbon black, but the rubber composition has limitations in satisfying consumer demands for fuel efficiency and wet road braking performance.

[0009] In addition, as a technology for simultaneously achieving the effects of improving wear resistance and driving performance, Korean Patent Publication No. 2009-0046427 provides a rubber composition including microcapsules containing a phase transition material.

[0010] Meanwhile, the tire industry is conducting research on various materials and design technologies to develop tires suited to specific weather conditions. Tires are broadly categorized into three types based on their seasonal use: all-season tires, summer tires, and winter tires. Each tire has different characteristics for its specific season, and its manufacturing process adapts to these characteristics. Furthermore, rubber compositions with properties tailored to each season are used during design.

[0011] Among these, summer tires are developed to provide performance suitable for dry and wet roads in temperatures above 7°C. Recently, demand has been increasing for summer tires with improved wear resistance and rolling resistance. Consequently, there is a need to develop tires that offer improved wear resistance and rolling resistance while also providing excellent grip on wet roads.

[0012] [Prior Art Literature]

[0013] [Patent Document]

[0014] (Patent Document 1) Republic of Korea Publication Patent No. 2010-0058727

[0015] (Patent Document 2) Republic of Korea Publication Patent No. 2009-0046427

[0016] The main purpose of the present invention is to solve the above-described problems, and the task is to manufacture a summer tire rubber composition that can improve fuel efficiency and wet grip performance by adding plant-derived silica, and to provide a summer tire using the same.

[0017] In order to achieve the above purpose, one embodiment of the present invention provides a summer tire rubber composition, wherein the tire rubber composition comprises raw rubber containing unsaturated carbon bonds, a hydrocarbon polymer, and plant-derived silica, and the hydrocarbon polymer has a glass transition temperature of 40°C to 70°C and a softening point of 90°C to 120°C.

[0018] In a preferred embodiment of the present invention, it may be characterized by comprising 100 phr of the raw rubber; 1 to 80 phr of the hydrocarbon polymer; and 30 to 180 phr of the plant-derived silica.

[0019] In a preferred embodiment of the present invention, the hydrocarbon polymer may be characterized in that it is synthesized from any one monomer selected from dicyclopentadiene (DCPD), cyclopentadiene (CPD), a C5 hydrocarbon compound, a C9 hydrocarbon compound, alpha-methylstyrene (AMS), a terpene, and phenol.

[0020] In a preferred embodiment of the present invention, the hydrocarbon polymer may have a number average molecular weight of 350 g / mol to 600 g / mol, and a weight average molecular weight of 400 g / mol to 900 g / mol.

[0021] In a preferred embodiment of the present invention, the hydrocarbon polymer may be characterized as having an aromaticity of 5% to 60%.

[0022] In a preferred embodiment of the present invention, the plant-derived silica has a particle size of 150 m 2 / g or more BET surface area.

[0023] In a preferred embodiment of the present invention, the plant-derived silica may be characterized as being derived from any one of rice bran, rice husk, barley bran, wheat bran, and straw.

[0024] In a preferred embodiment of the present invention, the plant-derived silica is CTAB 140 m 2 / g or more, and may be characterized by a pH of 5 to 8.

[0025] In a preferred embodiment of the present invention, the plant-derived silica is represented by δ in the following formulas 1 and 2. 30 Si and δ 29 It can be characterized by all Si values ​​being greater than 0.00.

[0026] .....(Formula 1)

[0027] .....(Formula 2)

[0028] In equation 1 ( 30 Si / 28 Si) sample is the substance to be measured 28 About Si 30 is the ratio of Si, ( 30 Si / 28 Si)standard is a standard substance 28 About Si 30 is the ratio of Si, and in equation 2 ( 29 Si / 28 Si) sample is the substance to be measured 28 About Si 29 is the ratio of Si, ( 29 Si / 28 Si)standard is a standard substance 28 About Si 29 It is the ratio of Si.

[0029] In a preferred embodiment of the present invention, the raw rubber may be characterized by including at least one of natural rubber, polybutadiene rubber, polyisoprene rubber, and polystyrene-butadiene rubber having a glass transition temperature in the range of -150°C to -0°C.

[0030] Another embodiment of the present invention provides a vehicle tire comprising the above summer tire rubber composition.

[0031] According to the present invention, a rubber composition for a tire using a hydrocarbon polymer and plant-derived silica can improve fuel efficiency and wet grip performance of existing rubber compositions.

[0032] By applying the above tire rubber composition, a tire compound with improved wet grip performance and rolling resistance performance can be manufactured, and the effect of reducing carbon dioxide emissions at the stage of tire raw material acquisition and use can be obtained.

[0033] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains. In general, the nomenclature used herein is well known and commonly used in the art.

[0034] Throughout this specification, whenever a part is said to "include" a component, this does not mean that it excludes other components, but rather that it may include other components, unless otherwise specifically stated.

[0035] Adhesive resins used in the tire industry include petroleum resins, phenolic resins, and natural resins extracted and polymerized from natural products. Most of these resins are pelletized solids with a glass transition temperature (Tg) above room temperature, which is most commonly used for performance reasons and ease of metering during the manufacturing process.

[0036] However, the improvement in ground contact performance using adhesive resin inevitably causes a decrease in fuel efficiency because it is caused by the heat generation phenomenon and hysteresis due to the rigid molecular structure of the resin at the vibration frequency of the environment where friction occurs in the tire tread.

[0037] In addition, adhesive resins are generally raw materials used in adhesives and have a strong tendency to adhere to mills or rotors during the production process, which results in a decrease in productivity on site and a deterioration in mixing processability.

[0038] In addition, compounds used in the tread of summer tires or racing tires are commonly made with a high content of Process Oil in order to secure grip performance by lowering hardness. However, this high content of oil sometimes hinders the generation of shear force between the compound and the rotor in the mixer, causing difficulties in processing.

[0039] Accordingly, the purpose of the present invention is to provide a summer tire rubber composition that can improve grip performance on wet roads, wear resistance, and fuel efficiency, and workability in a production process, by using a hydrocarbon polymer having specific physical property values ​​instead of an adhesive resin that is typically used in the composition of a summer tire that requires a high level of grip performance, and by replacing mineral-derived silica, which is facing the difficulty of resource depletion, with plant-derived silica.

[0040] Specifically, the summer tire rubber composition according to the present invention comprises raw rubber containing unsaturated carbon bonds, a hydrocarbon polymer, and plant-derived silica, and by using a hydrocarbon polymer having a glass transition temperature of 40°C to 70°C and a softening point of 90°C to 120°C as a component included instead of an adhesive resin, a summer tire having improved fuel efficiency and wet grip performance can be manufactured compared to existing rubber compositions.

[0041] In a preferred embodiment of the present invention, the raw rubber may comprise 100 phr; 1 to 80 phr of the hydrocarbon polymer; and 30 to 180 phr of the plant-derived silica.

[0042] The plant-derived silica may contain 30 phr to 180 phr, preferably 50 phr to 150 phr, and more preferably 80 phr to 130 phr. When the plant-derived silica is used in an amount less than 30 phr, the reinforcing performance of the silica as a reinforcing filler may be disadvantageous, and wet grip performance may not be achieved. On the other hand, when the plant-derived silica exceeds 180 phr, the mixing processability of the rubber composition may be reduced.

[0043] In the present invention, the hydrocarbon polymer is a component included instead of an adhesive resin, and may have a glass transition temperature of 40°C to 70°C and a softening point of 90°C to 120°C.

[0044] If the glass transition temperature of the hydrocarbon polymer is less than 40°C, there is a possibility that sufficient wet grip performance improvement may not be achieved, and if it exceeds 70°C, there is a problem that low fuel efficiency performance may be reduced.

[0045] The above hydrocarbon polymer can be synthesized from any one monomer selected from hydrocarbons based on dicyclopentadiene (DCPD), cyclopentadiene (CPD), C5 hydrocarbon compounds, C9 hydrocarbon compounds, C5 and C9 aliphatic resins, Rosin, alpha-methylstyrene (AMS), terpenes, phenols, etc.

[0046] Specifically, the hydrocarbon polymer may be a petroleum resin obtained through copolymerization and hydrogenation of a C5 aliphatic olefin and a C9 aromatic olefin generated in a naphtha thermal cracking process, and more specifically, may be a petroleum resin obtained by removing double bonds in the molecular structure through a hydrogenation reaction of a polymerized petroleum resin using a mixture of dicyclopentadiene (DCPD) separated by dimerizing cyclopentadiene in a C5 fraction and a C9 fraction.

[0047] The hydrocarbon polymer of the present invention can improve grip and wear resistance on high-temperature, wet roads. Furthermore, the hydrocarbon polymer of the present invention can partially or completely replace the adhesive resin used as an adhesive, thereby improving fuel efficiency and preventing deterioration of processability caused by high adhesive resin content during the refining process.

[0048] In a preferred embodiment of the present invention, the number average molecular weight of the hydrocarbon polymer may be from 350 g / mol to 600 g / mol, and the weight average molecular weight may be from 400 g / mol to 900 g / mol.

[0049] When the number average molecular weight of the hydrocarbon polymer is less than 350 g / mol or the weight average molecular weight is less than 400 g / mol, there is a problem that the G' of the compound may be reduced, and when the number average molecular weight exceeds 600 g / mol or the weight average molecular weight exceeds 900 g / mol, there is a problem that causes a reduction in the mixing processability.

[0050] Meanwhile, the hydrocarbon polymer has a chemical structure containing double bonds because it has not undergone a hydrogenation process. The presence or absence of double bonds in the hydrocarbon polymer can affect the sulfurized vulcanization structure formed after the vulcanization process, ultimately altering key tire performance, such as wear resistance and rolling resistance.

[0051] In a preferred embodiment of the present invention, the hydrocarbon polymer may have an aromaticity of 5% to 60%.

[0052] When the aromaticity of the hydrocarbon polymer is less than 5%, the fluidity of the molecular structure increases, which increases the plasticizing effect and may lower the G' of the compound. In addition, when the aromaticity exceeds 60%, the fluidity of the molecular structure decreases, which may increase the Tg and lower the fuel efficiency.

[0053] Here, the summer tire rubber composition of the present invention may include plant-derived silica as a reinforcing filler. In this case, it is preferable to use plant-derived silica alone or in combination with plant-derived glass silica and carbon black.

[0054] In a preferred embodiment of the present invention, the plant-derived silica is measured by ISO 18852 and has a particle size of 150 m 2 / g to 300 m 2 / g can have a BET surface area.

[0055] The BET surface area of ​​the above plant-derived silica is 150 m 2 / g or less, the reinforcing performance of silica, which is a reinforcing filler, may be disadvantageous, and wet grip performance may not be achieved. On the other hand, the BET surface area of ​​plant-derived silica is 300 m 2 If it exceeds / g, there is a problem that the mixing processability of the rubber composition may be reduced.

[0056] In a preferred embodiment of the present invention, the plant-derived silica may be derived from any one of rice bran, rice husk, barley bran, wheat bran, and straw.

[0057] In a preferred embodiment of the present invention, the plant-derived silica has a cetyl trimethyl ammonium bromide (CTAB) adsorption value of 140 m 2 / g or more, and the pH may be 5 to 8.

[0058] The CTAB adsorption value of the above plant-derived silica is 140 m 2 / g, the reinforcing performance of silica, which is a reinforcing filler, may be disadvantageous, while the CTAB adsorption value of plant-derived silica is 250 m 2 If it exceeds / g, there is a problem that the mixing processability of the rubber composition may be reduced.

[0059] If the pH of the plant-derived silica is less than 5, vulcanization of the rubber composition may be delayed, and if the pH of the plant-derived silica is more than 8, vulcanization of the rubber composition may be promoted, resulting in a problem in that the rubber composition does not have adequate reinforcing properties.

[0060] In addition, in a preferred embodiment of the present invention, the plant-derived silica is represented by δ in the following formulas 1 and 2. 30 Si and δ 29 It can be characterized by all Si values ​​being greater than 0.00.

[0061] .....(Formula 1)

[0062] .....(Formula 2)

[0063] In equation 1 ( 30 Si / 28 Si) sample is the substance to be measured 28 About Si 30 is the ratio of Si, ( 30 Si / 28 Si)standard is a standard substance 28 About Si 30 is the ratio of Si, and in equation 2 ( 29 Si / 28 Si) sample is the substance to be measured 28 About Si 29 is the ratio of Si, ( 29 Si / 28 Si)standard is a standard substance 28 About Si 29 It is the ratio of Si.

[0064] At this time, the standard material and the measurement target material 28 Si, 29 Si and 30 Si measurement can be performed without limitation in the art by any method capable of measuring silicon isotopes, for example, by using a standard material. 28 Si, 29 Si and 30 Si measurement can be done by dissolving standard materials such as NIST NBS 28 in hydrofluoric acid, pretreating them, and then measuring and quantitatively analyzing the Si isotope using ICP-MS, and the target material can be measured. 28 Si, 29 Si and 30 Si can be measured by preprocessing the tread rubber by extracting Si using hydrofluoric acid or by putting the tread rubber in a crucible, burning it, and extracting the remaining ash using hydrofluoric acid, and then quantitatively analyzing the Si isotope using ICP-MS.

[0065] In general, silicon (Si) has 24 known isotopes with atomic masses ranging from 22 to 45. Among these, 28 Si, 29 Si and 30 Si is a stable isotope, existing at 92.23%, 4.67%, and 3.1%, respectively, and there is a difference in the isotopic ratio between mineral-derived Si and plant-derived Si.

[0066] Accordingly, the summer tire rubber composition according to the present invention has δ in Equations 1 and 2. 30 Si and δ 29 By using plant-derived silica extracted from plants with Si values ​​of all 0.00 or higher, it is possible to replace mineral-derived silica, which is facing the difficulty of resource depletion, with plant-derived silica while improving fuel efficiency and wet grip performance.

[0067] Meanwhile, representative examples of 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, or N991.

[0068] A coupling agent may be additionally included to improve the dispersibility of plant-derived silica used as a reinforcing filler.

[0069] As the coupling agent, any one selected from the group consisting of sulfide-based silane compounds, mercapto-based silane compounds, vinyl-based silane compounds, amino-based silane compounds, glycidoxy-based silane compounds, nitro-based silane compounds, chloro-based silane compounds, methacrylic-based silane compounds, and combinations thereof may be used.

[0070] The above coupling agent may be included in an amount of 1 to 20 parts by weight based on 100 parts by weight of the raw rubber. If the content of the coupling agent is less than 1 part by weight, the dispersibility of the reinforcing filler may not be sufficiently improved, which may result in reduced processability of the rubber or reduced fuel efficiency. If the content exceeds 20 parts by weight, the interaction between the reinforcing filler and the rubber may be too strong, which may result in excellent fuel efficiency but significantly reduced braking performance.

[0071] In a preferred embodiment of the present invention, the raw rubber may include at least one of natural rubber, polybutadiene rubber, polyisoprene rubber, and polystyrene-butadiene rubber having a glass transition temperature in the range of -150°C to -0°C.

[0072] Meanwhile, the summer tire rubber composition of the present invention may optionally further include various additives such as additional vulcanizing agents, vulcanization accelerators, vulcanization accelerators, anti-aging agents, softeners, processing aids, or adhesives. Any additives commonly used in the field to which the present invention pertains may be used, and their contents are not particularly limited as they depend on the mixing ratio used in conventional tire rubber compositions.

[0073] As the above-mentioned curing agent, a sulfur-based curing agent can be preferably used. As the above-mentioned sulfur-based curing agent, an inorganic curing agent such as powdered sulfur (S), insoluble sulfur (S), precipitated sulfur (S), or colloidal sulfur can be used. Specifically, as the above-mentioned sulfur-based curing agent, elemental sulfur or a curing agent that produces sulfur, for example, amine disulfide, polymeric sulfur, etc. can be used.

[0074] It is preferable that the above vulcanizing agent be included in an amount of 0.5 to 4.0 parts by weight based on 100 parts by weight of the raw rubber, as this provides an appropriate vulcanizing effect and makes the raw rubber less sensitive to heat and more chemically stable.

[0075] The above vulcanization accelerator refers to an accelerator that accelerates the vulcanization speed or accelerates the retarding action in the initial vulcanization stage.

[0076] Meanwhile, the above-mentioned vulcanization accelerator is a compounding agent used in combination with the above-mentioned vulcanization accelerator to completely enhance its accelerating effect, and any one selected from the group consisting of inorganic vulcanization accelerators, organic vulcanization accelerators, and combinations thereof can be used.

[0077] As the above 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 may be used.

[0078] As the organic vulcanization accelerator, any one 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 may be used.

[0079] In particular, the zinc oxide and the stearic acid can be used together as the vulcanization accelerator, and in this case, the zinc oxide dissolves in the stearic acid to form an effective complex with the vulcanization accelerator, thereby creating advantageous sulfur during the vulcanization reaction, thereby facilitating the crosslinking reaction of the rubber.

[0080] When the zinc oxide and stearic acid are used together, they may be used in amounts of 1 to 5 parts by weight and 0.5 to 3 parts by weight, respectively, per 100 parts by weight of the raw rubber in order to function as appropriate vulcanization accelerators. When the contents of the zinc oxide and stearic acid are below the above range, the vulcanization speed may be slowed, which may lower productivity, and when they exceed the above range, a scorch phenomenon may occur, which may lower physical properties.

[0081] Meanwhile, the above-mentioned anti-aging agent is an additive used to stop the chain reaction that causes tires to automatically oxidize due to oxygen. The above-mentioned anti-aging agent may be any one appropriately selected from the group consisting of amine-based, phenol-based, quinoline-based, imidazole-based, carbamic acid metal salts, waxes, and combinations thereof.

[0082] Considering the conditions that the above-mentioned anti-aging agent must have high solubility in rubber, low volatility, be inert to rubber, and not inhibit vulcanization in addition to the anti-aging effect, the above-mentioned anti-aging agent may be included in an amount of 1 to 10 parts by weight per 100 parts by weight of the raw rubber.

[0083] Meanwhile, the softener is added to a rubber composition to impart plasticity to the rubber, facilitating processing, or to reduce the hardness of vulcanized rubber, and refers to oils or other materials used during rubber compounding or rubber manufacturing. The softener may be any one selected from the group consisting of petroleum oils, vegetable oils, and combinations thereof, but is not limited thereto.

[0084] In another preferred embodiment of the present invention, the present invention provides a vehicle tire comprising the summer tire rubber composition.

[0085] Hereinafter, the present invention will be described in more detail with reference to preferred embodiments. However, these embodiments are intended to illustrate the present invention more specifically, and it will be apparent to those skilled in the art that the scope of the present invention is not limited thereby.

[0086] Rubber compositions of examples and comparative examples were prepared using a hydrocarbon polymer (Oppera™PR 383 from ExxonMobil) having the properties shown in Table 1 below and the compositions shown in Table 2 below. The rubber compositions were prepared according to a conventional tire manufacturing method.

[0087] [Table 1] Properties of ExxonMobil's Oppera™PR 383

[0088]

[0089] [Table 2] Comparative and exemplary rubber compositions (unit: phr*)

[0090]

[0091] *phr: Parts per hundred rubber, weight of mixed material per 100 parts of raw rubber

[0092] Mooney viscosity, hardness, 300% modulus, and viscoelasticity were measured for rubber specimens of examples and comparative examples manufactured with the above composition, and the results are shown in Table 3.

[0093] [Table 3] Rubber properties of examples and comparative examples

[0094]

[0095] - Mooney viscosity (ML1+4) is the viscosity of uncured rubber measured with a Mooney viscometer. Generally, the rubber is placed at 100℃, preheated for 1 minute, the rotor is operated, and the value is measured after 4 minutes. The Mooney viscosity value measures the torque of uncured rubber when the rotor rotates, and if this value is low within the appropriate range, it is judged to have good flowability and excellent processability.

[0096] - Hardness indicates the resistance of vulcanized rubber to local plastic deformation, and a higher value indicates better hardness.

[0097] - 300% modulus indicates the tensile strength when the vulcanized rubber specimen is elongated by 300%, and a higher number means better strength.

[0098] - Elongation measures the elongation at which a specimen breaks during a tensile test of vulcanized rubber.

[0099] - 60 ℃ tan δ is measured through a viscoelasticity test of vulcanized rubber. The tan δ value of the specimen was measured from 0.5% to 5.0% strain at 60 ℃ and 10 Hz frequency. Among them, the smaller the 60 ℃ tan δ value at 5.0% strain, the less heat generation during driving and the better the rolling resistance.

[0100] As shown in Table 3 above, when Examples 1 to 4, in which a hydrocarbon polymer additive and plant-extracted silica were applied together according to the composition of Table 2, were compared with the case of using general silica (Comparative Example 1), the proportion of plasticizer in the compound increased, and the hardness and 300% modulus tended to decrease.

[0101] On the other hand, the higher the 0 ℃ tan δ value used as an indicator of wet grip performance, the more advantageous the wet grip performance is. Since Examples 1 to 4 have a 0 ℃ tan δ that is 10% higher than that of Comparative Example 1, advantageous wet grip performance can be expected.

[0102] In addition, the lower the 60 ℃ tan δ value, which is used as a measurement standard for cloud resistance in low-fuel-consumption performance, the more advantageous the low-fuel-consumption performance is. Since Examples 1 to 4 have 60 ℃ tan δ that is 10% or more lower than that of Comparative Example 1, advantageous low-fuel-consumption performance can be expected. Finally, in terms of lap wear performance, the LAT-100 evaluation results show that Examples 1 to 4 show the same level of wear resistance as that of Comparative Example 1, so similar mileage can be expected.

[0103] While the technical concepts of the present invention described above have been specifically described in preferred embodiments, it should be noted that the embodiments are intended for illustrative purposes only and are not intended to be limiting. Furthermore, those skilled in the art will appreciate that various embodiments are possible within the scope of the technical concepts of the present invention. Therefore, the true scope of technical protection of the present invention should be determined by the technical concepts of the appended claims.

Claims

1. In a rubber composition for tires, The above tire rubber composition comprises raw rubber containing unsaturated carbon bonds, hydrocarbon polymer and plant-derived silica, A summer tire rubber composition characterized in that the glass transition temperature of the hydrocarbon polymer is 40°C to 70°C and the softening point is 90°C to 120°C.

2. In paragraph 1, 100 phr of the above raw rubber; 1 phr to 80 phr of the hydrocarbon polymer; and A summer tire rubber composition comprising 30 to 180 phr of the plant-derived silica.

3. In paragraph 1, A summer tire rubber composition characterized in that the hydrocarbon polymer is synthesized from any one monomer selected from dicyclopentadiene (DCPD), cyclopentadiene (CPD), a C5 hydrocarbon compound, a C9 hydrocarbon compound, alpha-methylstyrene (AMS), terpene, and phenol.

4. In paragraph 1, A summer tire rubber composition, characterized in that the hydrocarbon polymer has a number average molecular weight of 350 g / mol to 600 g / mol and a weight average molecular weight of 400 g / mol to 900 g / mol.

5. In paragraph 1, A summer tire rubber composition characterized in that the hydrocarbon polymer has an aromaticity of 5% to 60%.

6. In paragraph 1, The above plant-derived silica is 150 m 2 A summer tire rubber composition characterized by having a BET surface area of / g or more.

7. In paragraph 6, A summer tire rubber composition characterized in that the plant-derived silica is derived from any one of rice bran, rice husk, barley bran, wheat bran, and straw.

8. In paragraph 6, The above plant-derived silica is CTAB 140 m 2 A summer tire rubber composition characterized by having a pH of 5 to 8 and a weight average molecular weight of 100,000 to 150,000.

9. In paragraph 1, The above plant-derived silica is δ in the following formulas 1 and 2 30 Si and δ 29 A summer tire rubber composition characterized in that all Si values are 0.00 or greater: .....(Formula 1) .....(Formula 2) In equation 1 ( 30 Si / 28 Si) sample is the substance to be measured 28 About Si 30 is the ratio of Si, ( 30 Si / 28 Si)standard is a standard substance 28 About Si 30 is the ratio of Si, and in equation 2 ( 29 Si / 28 Si) sample is the substance to be measured 28 About Si 29 is the ratio of Si, ( 29 Si / 28 Si)standard is a standard substance 28 About Si 29 It is the ratio of Si.

10. In paragraph 1, A summer tire rubber composition characterized in that the raw rubber comprises at least one of natural rubber, polybutadiene rubber, polyisoprene rubber, and polystyrene-butadiene rubber having a glass transition temperature in the range of -150°C to -0°C.

11. A vehicle tire comprising a summer tire rubber composition according to any one of claims 1 to 10.

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