KR102612230B1 - Method of manufacturing tire tread rubber and tire tread manufactured by using it - Google Patents

Abstract

The present invention discloses a method for manufacturing a rubber composition for a tire tread and a tire tread thereof.
According to the method for producing a rubber composition for a tire tread according to the present invention and the tire tread thereof, there are steps of producing a carbon nanotube coupling agent by reacting zinc oxide and a silane coupling agent, and dispersing the carbon nanotube coupling agent in a solvent. It is characterized in that it includes the step of adding carbon nanotubes and reacting with ultrasonic waves to obtain modified carbon nanotubes, and the step of mixing raw rubber, silica, and the modified carbon nanotubes to prepare a masterbatch, whereby vulcanization occurs. As a reaction accelerator, it is possible to reduce zinc oxide, a Substance of Very High Concern (SVHC), and maintain physical properties without deteriorating silane reaction and vulcanization reaction.

Description

Method of manufacturing a rubber composition for a tire tread and a tire tread thereof {Method of manufacturing tire tread rubber and tire tread manufactured by using it}

The present invention relates to a method for manufacturing a rubber composition for a tire tread and a tire tread thereof, and more specifically, to reduce zinc oxide, a substance of very high concern (SVHC), as a vulcanization reaction accelerator, and to reduce zinc oxide, a substance of very high concern (SVHC), and silane reaction and vulcanization. It relates to a method for manufacturing a rubber composition for a tire tread that maintains physical properties without reaction degradation and a tire tread thereof.

Recently, environmental issues related to life cycle assessment (LCA) have been highlighted for various products.

The number of tires produced annually in Korea is approximately 98 million, and the annual amount of end-of-life tires (ELT) is estimated to be approximately 40 million.

These waste tire recycling methods are largely divided into three types. There is a recycling method through processing using recycled tires, rubber powder (Tire Granulate), rope, etc., and a method using heat through a cement kiln or incineration. There is a circular use method that uses materials for export and civil engineering or landfill construction.

In relation to the above, heat utilization methods through cement kilns or dry distillation incineration (cogeneration) are mainly used in Korea. However, since tires contain synthetic rubber and zinc as raw materials, harmful synthetic substances are emitted during the combustion process. In addition, dioxins caused by chlorides, dioxins generated during incomplete combustion of benzene, furans, PCBs (polychlorinated biphenols), and PHAs (polyaronatic hydrocarbons) are emitted, which can cause air pollution.

In particular, Tire and Road Wear Particles (TRWP; Tire and Road Wear Particles), which are generated during the driving process due to friction between tire tread rubber and the road surface, are transported by various environmental factors including wind and rainwater, air and soil. , may cause environmental problems in rivers, seas, etc.

Conventional eco-friendly tires are known to not only improve the fuel efficiency of vehicles by reducing frictional resistance or rolling resistance with the road (minimizing energy loss) and thus use less energy (petrochemical resources), but also reduce carbon dioxide emissions. there is.

However, reduction and replacement of Substances of Very High Concern (SVHC) used as raw materials for tires, use of eco-friendly raw materials, reduction in the amount of wear particles generated by improving wear resistance, and reduction in the amount of scrap tires generated by increasing the tire replacement cycle. It can be said to be an eco-friendly tire in a broad sense.

Recently, environmental regulations are expanding worldwide. Management, including restrictions and bans on existing high-risk controlled substances, is being strengthened, and registration of new high-risk controlled substances for hazardous chemicals is expanding. In relation to this, zinc oxide, which has a negative impact on the aquatic ecosystem, is also being classified by country. Designation of high-risk controlled substances and regulatory measures are being discussed.

In relation to the above, the tire manufacturing industry is also conducting research on substitutes and weight reduction for zinc oxide, which is used as a cross-linking activator in tires, but there are limitations due to safety issues for consumers due to a decrease in the performance and durability required for tires.

Republic of Korea Patent No. 10-1382194 Republic of Korea registered patent 10-2180689

Therefore, the first technical problem that the present invention aims to solve is to reduce zinc oxide, a substance of very high concern (SVHC), as a vulcanization reaction accelerator, and to provide tire tread rubber that maintains physical properties without reducing silane reaction and vulcanization reaction. The purpose is to provide a method for manufacturing the composition.

In addition, the second technical problem that the present invention aims to solve is to reduce zinc oxide, a substance of very high concern (SVHC), as a vulcanization reaction accelerator, and to provide a tire tread that maintains physical properties without reducing silane reaction and vulcanization reaction. The aim is to provide a tire thread using a method for manufacturing a rubber composition.

In order to solve the above-described technical problem, the present invention includes the steps of reacting zinc oxide and a silane coupling agent to produce a carbon nanotube coupling agent, adding carbon nanotubes to the solvent in which the carbon nanotube coupling agent is dispersed, and A method for producing a rubber composition for a tire tread is provided, comprising the steps of reacting to obtain modified carbon nanotubes and mixing raw rubber, silica, and the modified carbon nanotubes to produce a masterbatch.

According to another embodiment of the present invention, a process of manufacturing a final masterbatch may be further included after manufacturing the masterbatch.

Meanwhile, in order to solve the second technical problem described above, the present invention provides a tire thread rubber manufactured by the above-described manufacturing method.

According to the method for producing a rubber composition for a tire tread according to the present invention and the tire tread thereof, zinc oxide, a substance of very high concern (SVHC), is reduced as a vulcanization reaction accelerator, and without reducing the silane reaction and vulcanization reaction, Physical properties can be maintained.

Hereinafter, the present invention will be described in more detail.

Hereinafter, the present invention will be described in detail using examples to aid understanding of the present invention. However, the following examples are merely illustrative of the content of the present invention and the scope of the present invention is not limited to the following examples.

Examples of the present invention are provided to more completely explain the present invention to those skilled in the art.

In addition, although the present invention describes specific parts in detail, it will be clear to those skilled in the art that these specific descriptions are merely preferred embodiments and do not limit the scope of the present invention thereby. , the actual scope of the present invention will be defined by the appended claims and their equivalents.

The method for producing a rubber composition for a tire tread according to the present invention includes the steps of reacting zinc oxide and a silane coupling agent to produce a carbon nanotube coupling agent, adding carbon nanotubes to the solvent in which the carbon nanotube coupling agent is dispersed, and ultrasonic waves. It is characterized in that it includes the step of obtaining modified carbon nanotubes by reacting with and the step of mixing raw rubber, silica, and the modified carbon nanotubes to prepare a masterbatch.

First, the step of producing a carbon nanotube coupling agent by reacting zinc oxide with a silane coupling agent denatures the carbon nanotubes to maintain physical properties while reducing zinc oxide, which is a Substance of Very High Concern (SVHC) as an accelerator. A rubber composition for tire treads can be manufactured.

As can be seen in Scheme 1 below, a carbon nanotube coupling agent can be produced by reacting a hydroxyl group on the surface of zinc oxide with an alkoxy group of a silane coupling agent, and can be powdered after drying.

<Scheme 1>

Next, carbon nanotubes are added to the solvent in which the carbon nanotube coupling agent is dispersed and reacted with ultrasonic waves to obtain modified carbon nanotubes. This is a process of reacting the carbon nanotube coupling agent with the carbon nanotubes.

In other words, it is a process of denaturation through a reaction between the hydroxyl group of zinc oxide of the carbon nanotube coupling agent or the hydroxyl group of the silane coupling agent and some carbons of the carbon nanotube.

Since the reaction proceeds by ultrasonic energy in the solvent, the intensity or strength of the ultrasonic waves is important, and it is necessary to react for 2 to 10 hours with 20 MHz to 40 MHz ultrasonic waves.

If it is less than 20 MHz, the reaction may be insufficient due to lack of dispersibility, and on the other hand, if it exceeds 40 MHz, the temperature of the solvent may rise rapidly, making a uniform reaction impossible. Additionally, if the reaction time is less than 2 hours, the reaction may be insufficient, and conversely, if it exceeds 10 hours, the next process may be difficult due to the reverse reaction (solidification or cake).

Next, there is a step of producing a masterbatch by mixing raw rubber, silica, and the modified carbon nanotubes. Here, it is important to uniformly disperse the modified carbon nanotubes, silica, and raw rubber.

Therefore, an additional process of manufacturing the final masterbatch may be necessary, which will be described later.

For uniform dispersion, 100 parts by weight of raw rubber can be added to the mixer, and additional pre-mixing can be performed. 30 to 40 parts by weight of silica and a silane coupling agent ( For example, 5 to 8 parts by weight of 3-Octanoylthio-1-Propyltriethoxysilane), 30 to 40 parts by weight of silica, 5 to 10 parts by weight of modified carbon nanotubes, processing oil, and additives are added and mixed, and sweep ( After performing the sweep operation, mix further.

Here, it may be necessary to maintain the mixing (mixing) speed and temperature at 50 to 70 Rpm and below 150°C (Dump temperature, 150°C) based on the Banbury Mixer.

Before the sweep operation, a very small amount of zinc oxide (0.5 parts by weight or less) can be added for mixing. Generally, zinc oxide is used as a vulcanization activator during the tire rubber manufacturing process and is used during the vulcanization process. By lowering the reaction energy between sulfur and the accelerator, it is possible to control the length of the sulfur bond in the polymer chain. In other words, if zinc oxide is not used, the crosslink length becomes very long (polysulfide) due to a rapid bonding reaction caused by sulfur at high temperature. It is advantageous for braking performance, but very disadvantageous for wear and fuel efficiency, so it is necessary to use a minimum amount of zinc oxide to ensure the uniform performance required for tires (long or short crosslink length (Mono- / di) type) (requires a cross-linked chain)

In the production of the final masterbatch mentioned above, 2 to 5 parts by weight of sulfur, a vulcanizing agent, and 1.5 to 3 parts by weight of an accelerator are added to 100 parts by weight of the masterbatch and kneaded for 3 minutes. The kneading speed and temperature are 30 to 40 Rpm based on a Banbari mixer. Kneading is done by maintaining the temperature below 100℃. If the mixing speed is high or the time is long, the temperature of the mixture may rise above 100℃, and a vulcanization reaction occurs, making the rubber sheet too hard or viscous to extrude. And problems may occur during the molding process.

The accelerator includes dithiocarbamate accelerators Zinc dimethyldithiocarbamate (ZMDC) (Formula 1), Zinc diethyldithiocarbamate (ZEDC) (Formula 2), Zinc dibuthyldithiocarbamate (ZBDC) (Formula 3), and Zinc dibenzyldithiocarbameaate (ZBzDC) (Formula 2). Chemical formula 4) can be used.

<Formula 1>

<Formula 2>

<Formula 3>

<Formula 4>

Manufacturing example: Manufacture of modified carbon nanotubes

After drying zinc oxide (ZnO) at 110°C for 24 hours, 0.5 to 1 g of dried zinc oxide was added to 100 to 200 ml of ethanol (purity of 99.5% or higher) and ultrasonicated (ultrasonification, 30 MHz) for 30 minutes. It was done for 30 minutes. Afterwards, 0.08 to 0.15 ml of silica coupling agent (3-Octanoylthio-1-propyltriethoxysilane; NXT) was added, sonicated for 30 minutes, and the mixture was filtered (using ethanol and water, twice each) and incubated at 60°C for 24 to 48 minutes. A carbon nanotube coupling agent was prepared by drying for a period of time. Next, 1 g of carbon nanotube coupling agent was added to 100 ml of anhydrous ethanol and dispersed for 2 hours, then 10 g of carbon nanotubes were added and sonicated for 4 hours. Afterwards, the solvent was removed and the obtained solid was incubated at 80°C for 2 hours. Modified carbon nanotubes were prepared by vacuum drying.

Examples and Comparative Examples

A rubber composition having a glass transition temperature of -20 to -15°C according to the present invention (unit of weight part) was prepared according to the composition shown in Table 1 below.

That is, put 100 parts by weight of raw rubber into the mixer and perform pre-mixing for 1 minute. And for 100 parts by weight of manuscript rubber, 30 to 40 parts by weight of silica, 5 to 8 parts by weight of silane (3-Octanoylthio-1-Propyltriethoxysilane; NXT (Formula 5)), and 0 to 0.5 parts by weight of zinc oxide were added and mixed. ) for 2 minutes, add 30 to 40 parts by weight of silica, 5 to 10 parts by weight of modified carbon nanotubes, processing oil, and additives for 1 minute, perform a sweep operation, and knead for another 3 minutes. Here, the kneading speed and temperature were maintained at 50 to 70 Rpm and below 150°C (dump temperature, 150°C) based on the Banbury Mixer, and after producing the masterbatch, 100 parts by weight of the masterbatch and 2 to 2% of sulfur, a vulcanizing agent, were added. Add 5 parts by weight and 1.5 to 3 parts by weight of accelerator and knead for 3 minutes. Here, the kneading speed and temperature are maintained at 30 to 40 Rpm and 100 ℃ or less based on the Banbari mixer. At this time, the kneading speed is high or the time is long. There are cases where the temperature of the ground mixture rises above 100℃, and a vulcanization reaction occurs, which can cause problems during extrusion and molding processes due to the rubber sheet being too hard or lacking in viscosity.

The physical properties of the rubber composition were confirmed by using modified carbon nanotubes and mixing them into an eco-friendly rubber composition for tire treads that minimized the use of zinc oxide.

However, the carbon nanotubes and zinc oxide modified during the manufacturing process were added at the same time in order not to reduce the silane reaction efficiency.

In addition, as in the mixing ratio disclosed in Table 1, the materials and manufacturing process used were the same as in Comparative Example 2, but in order to confirm the difference in crosslinking density due to the modified carbon nanotube and the physical properties of the rubber composition, the modified carbon nanotube Rubber compositions were prepared by varying the amount used. However, in order to maintain the same mixing conditions as much as possible, the amount of carbon nanotubes used was adjusted according to the amount of modified carbon nanotubes used (modified carbon nanotubes: carbon nanotubes = 2.5:1).

division Material name Comparative Example 1 Comparative example 2 Example 1 Example 2 Example 3 Example 4 MB (Master Batch) SBR-1 ¹⁾ 60 60 60 60 60 60 SBR-2 ²⁾ 25 25 25 25 25 25 BR ³⁾ 15 15 15 15 15 15 Silica ⁴⁾ 65 65 65 65 65 65 Silica coupling agent ⁵⁾ 6 6 6 6 6 6 ZnO 3 0.5 0.5 0.5 0.5 0.5 Additive-1 ⁶⁾ 7 7 7 7 7 7 CNT ⁷⁾ 5 5 4 3 2 One Modified CNT ⁸⁾ - - 2.5 5 7.5 10 Stearic Acid 1.8 0.3 0.3 0.3 0.3 0.3 Process Oil ⁹⁾ 5 5 5 5 5 5 Additive-2 ¹⁰⁾ 4 4 4 4 4 4 FM
(Final Batch) MB 196.8 192.8 194.3 195.8 197.3 198.8 Sulfur 1.6 1.6 1.6 1.6 1.6 1.6 Accelerator-1 ¹¹⁾ 2.2 2.2 2.2 2.2 2.2 2.2

1) SBR-1: Solution-polymerized styrene-butadiene-modified rubber with a hydrophilic group introduced, with styrene content of 25% by weight and vinyl content in butadiene of 15%, glass transition temperature of approximately -60°C.

2) SBR-2: Solution-polymerized styrene-butadiene-modified rubber with a hydrophilic group introduced, with a styrene content of 42% by weight and a vinyl content in butadiene of 18%, glass transition temperature of approximately -25°C.

3) BR: Silica-friendly butadiene synthetic rubber polymerized with Nd as a catalyst, contains at least 93% of 1.4-Cis, has excellent wear performance, and glass transition temperature is approximately -105°C.

4) Silica: Zeosil®200MP from SOLVAY / Nitrogen adsorption surface area BET (m2/g) 215.

5) Silica coupling agent: Evonik's silane coupling agent / 3-Octanoylthio-1-propyltriethoxysilane; NXT.

6) Additive-1: An additive commonly used in tire rubber compositions that is a mixture of a silane reaction accelerator and a silica dispersant.

7) CNT: Carbon Nano tube of Kumho Petrochemical / 100 Grade CNT / Length 20 ~ 30μm / Bulk density 0.025 g/ml.

8) Modified CNT: Modified CNT manufactured by the manufacturing method described in the present invention using the above CNT as a raw material.

9) Process Oil: Treated distillate aromatic extract oil with more than 35% Aromatic ring carbon from Far East Oil; TDAE.

10) Additiv2: An additive commonly used in tire rubber compositions that is a mixture of light or heat anti-aging agent and wax.

11) Accelerator1: Comparative Examples 1 and 5 were N-Cyclohexyl-2-benzothiazolylsulfenamide; CZ; CBS was used, and Examples 1 to 4 used materials corresponding to Chemical Formulas 1 to 4, respectively.

Experimental Example 1: Measurement of physical properties of the manufactured rubber composition

Crosslinking Density and Sulfur Length were measured for each rubber specimen prepared in the above Examples and Comparative Examples, and viscoelasticity (Tensile), Dynamic Viscoelasticity (DMA), Abrasion (Din Abrasion, Field Performance) The physical properties of the System (FPS) and RTMs (Rotational Traction Measuring System) were measured according to ASTM related regulations, and the results are shown in Table 2 below.

Item value (relative index) Comparative Example 1 Comparative example 2 Example 1 Example 2 Example 3 Example 4 Chemical Analysis Crosslinking Density (mol/cm ³ ) ^{1) 0.369 0.293 0.351 0.365 0.371 0.395} mono- (mol/cm ³ ) ^{1) 0.567 0.492 0.574 0.586 0.611 0.651} di- (mol/cm ³ ) ^{1) 0.155 0.092 0.156 0.164 0.175 0.192} poly- (mol/cm ³ ) ^{1) 0.348 0.279 0.33 0.343 0.348 0.369} Processability Mooney viscosity 100℃ ¹¹⁾ 77.37 (100) 71.46 (92) 75.91 (98) 77.29 (100) 77.37 (100) 78.31 (101) T05 ¹²⁾ 22.54 (100) 16.35 (73) 21.76 (97) 22.45 (100) 22.83 (101) 23.84 (106) T35 ¹²⁾ 35.42 (100) 21.45 (61) 34.24 (97) 35.28 (100) 35.74 (101) 37.2 (105) t50 ¹³⁾ 1.69 (100) 1.45 (86) 1.62 (96) 1.7 (101) 1.74 (103) 1.85 (109) t90 ¹³⁾ 3.35 (100) 2.80 (84) 3.16 (94) 3.27 (98) 3.38 (101) 3.45 (103) Tensile HD's ²⁾ 57 (100) 55 (96) 56 (98) 57 (100) 57 (100) 58 (102) M100% ³⁾ 25.7 (100) 29.4 (114) 27.1 (105) 26.2 (102) 25.4 (99) 23.6 (92) M300% ³⁾ 103.1 (100) 122.4 (119) 111.8 (108) 108.3 (105) 102.8 (100) 102.4 (99) TS ⁴⁾ 223.6 (100) 210.5 (94) 213.8 (96) 217.6 (97) 222.7 (100) 223.8 (100) EB ⁴⁾ 489.4 (100) 449.3 (92) 463.6 (95) 483.1 (99) 487.5 (100) 488.3 (100) DMA Tg ⁵⁾ -15 (100) -15 (100) -15 (100) -15 (100) -15 (100) -15 (100) Tan δ 0℃ ⁶⁾ 0.777 (100) 0.786 (101) 0.77 (99) 0.777 (100) 0.784 (101) 0.811 (96) E" 0℃ ⁶⁾ 14.67 (100) 18.76 (128) 16.33 (111) 16.81 (115) 17.66 (120) 18.07 (123) Tan δ 22℃ ⁷⁾ 0.265 (100) 0.268 (101) 0.266 (101) 0.26 (98) 0.261 (99) 0.265 (100) E" 22℃ ⁷⁾ 1.81 (100) 2.11 (117) 2.02 (112) 2.15 (119) 2.16 (119) 2.4 (133) Tan δ 60℃ ⁸⁾ 0.072 (100) 0.077 (93) 0.072 (100) 0.069 (96) 0.069 (96) 0.079 (109) Abrasion DIN ⁹⁾ 0.099 (100) 0.131 (68) 0.102 (103) 0.103 (104) 0.102 (103) 0.105 (106) FPS ⁹⁾ 1.024 (100) 1.125 (90) 1.075 (105) 1.077 (105) 1.075 (105) 1.081 (106) RTMs Dry μ ¹⁰⁾ 1.379 (100) 1.476 (107) 1.426 (103) 1.458 (106) 1.472 (107) 1.502 (109) Wet μ ¹⁰⁾ 1.237 (100) 1.331 (108) 1.274 (103) 1.312 (106) 1.327 (107) 1.364 (110)

Referring to Table 2 above, based on Comparative Example 1, as zinc oxide is reduced, the cross-link density decreases, the cross-link length becomes longer and the mechanical properties (modulus) increase, the T.S/E.B value decreases, durability decreases, and viscoelasticity decreases. From the results of the tester and RTMs, it can be seen that braking performance improves, but fuel efficiency and wear performance decrease.

In addition, based on Comparative Example 1, it can be seen that the braking performance was improved while maintaining the fuel efficiency and wear performance of Examples 1 to 3 in which zinc oxide was reduced (3 → 0.5 phr) and modified carbon nanotubes were added. It can be seen that as the additive content increases, the degree of improvement in braking performance increases.

In addition, as in Example 4, when the modified carbon nanotube content was added at 10 phr or more, braking performance was significantly improved, but fuel efficiency and wear performance were confirmed to be somewhat reduced.

- Crosslinking density is a test method that measures the degree of crosslinking reaction of the vulcanized rubber composition after the vulcanization process. It can be measured by the degree to which crosslinking is broken by chemicals. Depending on the crosslink length, mono- (S1), di- ( It can be divided into S2) and poly- (SX), and density represents the total crosslinked molecular weight and is expressed as a molar value per unit volume.2) HD's refers to the hardness of the rubber composition, and its shape changes under external force. Indicates the degree of change.

- M100% and M300% (Modulus; M) represent the force used (measured) when a rubber specimen is stretched 100% or 300% due to a certain force during the tensile test process. The larger the value, the better the elastic modulus.

- T.S (Tensile strength) and E.B (Elongation broken) refers to the maximum rate at which a rubber specimen is elongated due to a certain force during the tensile test process (the moment the rubber specimen breaks), and the force measured at that time is called T.S. .

- Tg refers to the temperature at which polymer branches become active and begin to move due to temperature.

- Tan δ 0℃ and E”0℃ are measured by a DMA (Dynamic Mechanical Analysis) tester and are the results of measurements at 11Hz. It is used as an index of wet road braking performance, and the higher the number, the better the wet road braking performance.

In addition, Tan δ means the value obtained by dividing E' (Storage Energy) by E' (Loss Energy).

- Tan δ 22℃ and E”22℃ are measured by a DMA (Dynamic Mechanical Analysis) tester and are the results measured at 11Hz. It is used as an index of dry road braking performance, and the higher the number, the better the dry road braking performance.

- Tanδ@ 60℃ is measured by a DMA (Dynamic Mechanical Analysis) tester and is the result of measurement at 11Hz. It is used as an index of rolling resistance performance, and the lower the number, the better the rolling resistance performance.

- DIN and FPS abrasion tests are evaluated to predict tire wear. They measure the weight difference (loss weight (g)) of the rubber specimen before and after the test. In the case of the DIN test, it is an abrasion test that is greatly affected by load. This is the law, and FPS is a wear test evaluation method that can be performed in a laboratory that is most similar to actual vehicle evaluation. Based on Comparative Example 1, the higher (lower) the value (relative index) is, the worse the wear characteristics are.

- The coefficient of friction (μ) is the result measured by an RTMs (Rotational Traction Measuring system) tester. Depending on the road surface condition, it is used as an index for dry road braking performance or as an index for wet road braking performance. A higher value means better braking performance.

- As a result of evaluation in scorch time measurement mode on a mooney viscosity tester, Mv 125℃ is the viscosity value of the rubber composition at 125℃, and T05 and T35 are the initial viscosity of the rubber composition. Or it represents the time it takes to increase by 35. The lower the T05 and T35 values, the faster the vulcanization speed of the rubber composition, and the lower the difference between T35 and T05, the worse the process stability.

- MonTech's MDR (moving die rheometer)-3000 is used to measure the time required according to the level of vulcanization. t50 and t90 represent the time required for the crosslinking reaction rate of the rubber composition to reach 50% and 90%.

Experimental Example 2: Tire performance evaluation using the manufactured rubber composition

A 205/55 R16 tire was manufactured using a rubber composition for an eco-friendly tire tread with reduced zinc oxide using the modified carbon nanotubes of the present invention, and the performance of the finished tire was evaluated using an actual vehicle.

In addition, the comparative examples and examples have the same structure and pattern, only the tread rubber is changed, and the handling performance, braking performance, fuel efficiency, and wear performance of each manufactured tire are measured, and the results are shown in Table 3 below. shown in

Item value (relative index) Comparative Example 1 Example 1 Example 3 Example 4 Dry Braking (m) 36.6 (100) 35.9 (102) 34.8 (105) 32.9 (110) Wet Braking (m) 28.6 (100) 27.7 (103) 26.9 (106) 25.5 (111) RR (Rolling Resistance) 5.82 (100) 5.87 (99) 5.9 (99) 6.14 (95) Wear Index ¹⁾ 8,138 (100) 8,125 (100) 8,088 (99) 7,531 (93)

- Wear Index: Distance that can be driven per 1 mm of rubber composition for tire tread (km)

Compared to Comparative Example 1, it was confirmed that Example 2 of the rubber composition for tire tread of the present invention in which zinc oxide was reduced and modified carbon nanotubes were applied showed improved braking performance without deterioration in fuel efficiency and wear performance.

In addition, Example 3 of the rubber composition for tire tread to which an excessive amount of modified carbon nanotubes were applied was found to have significantly improved braking performance, but decreased fuel efficiency and wear performance compared to Comparative Example 1.

By using the rubber composition prepared according to the present invention in the tire tread area, it is possible to manufacture an eco-friendly tire with excellent braking performance without deteriorating the wear performance and fuel efficiency of the tire.

In addition, the modified carbon nanotubes used as raw materials for the rubber composition can significantly improve braking performance while maintaining the physical properties of the rubber composition, despite reducing zinc oxide, which can cause environmental problems.

In addition, the modified carbon nanotubes used as raw materials for the rubber composition can be used to manufacture tires without problems with vulcanization and processing stability due to the use of a super accelerator, which is a zinc oxide weight loss substitute.

Claims (3)

Preparing a carbon nanotube coupling agent by reacting zinc oxide with a silane coupling agent;
Adding carbon nanotubes to the solvent in which the carbon nanotube coupling agent is dispersed and reacting with ultrasonic waves to obtain modified carbon nanotubes; and
A method for producing a rubber composition for a tire tread, comprising the step of mixing raw rubber, silica, and the modified carbon nanotubes to produce a masterbatch.
According to claim 1,
It further includes a process of manufacturing a final masterbatch after manufacturing the masterbatch, wherein the final masterbatch manufacturing involves adding 2 to 5 parts by weight of sulfur, which is a vulcanizing agent, and 1.5 to 3 parts by weight of an accelerator and kneading them, based on 100 parts by weight of the masterbatch. Method for manufacturing a rubber composition for a tire tread, characterized by:
A tire thread manufactured by the manufacturing method according to claim 1 or 2.