KR101442213B1 - Rubber composition for tire tread and tire manufactured by using the same - Google Patents

Abstract

The present invention relates to a rubber composition for a tire tread and to a tire produced therefrom, which comprises 50 to 70 parts by weight of a batch-type solution-polymerized styrene-butadiene rubber, 20 to 40 parts by weight of a continuous solution-polymerized styrene-butadiene rubber, 10 to 20 parts by weight of a raw rubber, and 70 to 90 parts by weight of a reinforcing filler containing silica.
The rubber composition for a tire tread can improve a low fuel consumption performance without deteriorating braking performance on a wet road surface.

Description

TECHNICAL FIELD [0001] The present invention relates to a rubber composition for a tire tread, and a tire manufactured using the same. BACKGROUND OF THE INVENTION [0002]

The present invention relates to a rubber composition for a tire tread and a tire produced using the same. More particularly, the present invention relates to a rubber composition for a tire tread capable of improving a low fuel consumption performance without deteriorating the braking performance and a tire produced using the same .

As the economic growth including the automobile industry has become more active, demand for automobiles has increased, and since the labeling system for tires has been introduced in Europe and Japan from this year, It is getting higher.

Commonly known tire performances include braking performance on dry roads and wet road surfaces, handling and riding performance, low fuel consumption performance, and wear resistance performance. Some of these performances have one performance When you choose performance, you will have a trade-off tendency where the other performance is disadvantageous.

In particular, the labeling system, which will be implemented from this year, will provide consumers with information on braking performance and low fuel consumption performance on wet roads on tires. These two performances are trade-off performance, Efforts have been continuing.

The tendency of the trade-off between braking performance on the wet road surface and low fuel consumption performance is shown as the rubber is deformed as the tire travels, and hysteresis heat loss occurs at this time. The higher the hysteresis heat loss, the better the braking performance on the wet road surface The smaller the rotational resistance, the better the fuel-efficiency performance.

In terms of composition, there is generally a method of increasing the reinforcing filler in order to improve the braking performance on the wet road surface. When the reinforcing filler is increased, hysteresis heat loss is generated by the filler-filler bond, But it is a principle that it can be improved by reducing the amount of reinforcing filler for the fuel-efficient performance which tends to trade-off.

Recently, a lot of research and development has been carried out to overcome this trade-off performance. Furthermore, efforts are being actively made to acquire a high label in the labeling system of Europe and Japan.

Korean Patent Publication No. 2003-0015932 Korea Patent No. 0762207

An object of the present invention is to provide a rubber composition for a tire tread capable of improving a low fuel consumption performance without lowering the braking performance.

Another object of the present invention is to provide a tire produced by using the rubber composition for a tire tread.

To achieve the above object, a rubber composition for a tire tread according to an embodiment of the present invention comprises 50 to 70 parts by weight of a batch-type solution-polymerized styrene-butadiene rubber, 20 to 40 parts by weight of a continuous solution-polymerized styrene- 100 parts by weight of a raw rubber comprising 10 to 20 parts by weight of a butadiene rubber, and 70 to 90 parts by weight of a reinforcing filler containing silica.

Wherein the styrene-butadiene rubber has a styrene content of 20 to 40 wt%, a vinyl content of 30 to 50 wt% in butadiene, a glass transition temperature (Tg) of -20 to 40 DEG C, a weight average molecular weight of 600,000 To 800,000 g / mol, a molecular weight distribution of 1.1 or less, and a terminal substituted with an aminoalkoxysilyl group.

Wherein the continuous solution-polymerized styrene-butadiene rubber has a styrene content of 30 to 50 wt%, a vinyl content of butadiene of 20 to 40 wt%, a glass transition temperature (Tg) of -30 to 50 DEG C, 1,200,000 to 1,700,000 g / mol, a molecular weight distribution of 1.5 or more, and the terminal thereof is substituted with an aminoalkoxysilyl group.

The SRAE oil may contain 20 to 40 parts by weight of SRAE oil per 100 parts by weight of the rubbery component of the continuous solution-polymerized styrene-butadiene rubber. The SRAE oil is a reextracted oil extracted from the TDAE oil. The PAE (Polycyclic Aromatic Hydarbon ) Component is not more than 3 wt%, the kinematic viscosity is not less than 210 (210 S SUS), the aromatic component in the oil is in the range of 15 to 25 wt%, the naphthenic component is in the range of 35 to 55 wt% 45% by weight.

The neodymium-butadiene rubber may have a glass transition temperature (Tg) of -100 to -110 ° C and a molecular weight distribution of 1.5 to 2.5.

The silica may have a nitrogen adsorption amount of 160 to 180 m 2 / g, a CTAB value of 150 to 170 m 2 / g and a DBP oil absorption of 180 to 200 cc / 100 g.

A tire according to another embodiment of the present invention is manufactured using the rubber composition for a tire tread.

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

The rubber composition for a tire tread according to an embodiment of the present invention improves the performance of the low fuel consumption without deteriorating the braking performance on the wet road surface by utilizing the characteristics of various new rubber materials besides the reinforcing filler side.

That is, the rubber composition for a tire tread according to an embodiment of the present invention comprises 50 to 70 parts by weight of a batch-type solution-polymerized styrene-butadiene rubber, 20 to 40 parts by weight of a continuous solution-polymerized styrene-butadiene rubber and 10 to 30 parts by weight of neodymium- 100 parts by weight of a raw rubber containing 20 parts by weight of a reinforcing filler and 70 to 90 parts by weight of a reinforcing filler containing silica.

The rubber composition for a tire tread is prepared by using batch-type solution-polymerized styrene-butadiene rubber, continuous solution-polymerized styrene-butadiene rubber and neodymium butadiene rubber as raw material rubbers and silica as a reinforcing filler, Fuel ratio performance can be improved without occurrence of trade-off of the braking performance of the engine.

The batch-polymerized styrene-butadiene rubber is a rubber polymerized by a batch method and has a styrene content of 20 to 40% by weight, a vinyl content of 30 to 50% by weight in butadiene, and 50 to 70% By weight.

The glass transition temperature (Tg) of the batch solution-polymerized styrene-butadiene rubber is from -20 to -40 占 폚, the weight average molecular weight is from 600,000 to 800,000 g / mol, and the molecular weight distribution is 1.1 or less.

In addition, it is preferable that the batch-type solution-polymerized styrene-butadiene rubber is substituted with an aminoalkoxysilyl group at the terminal thereof and does not contain an oil.

Batch solution-polymerized styrene-butadiene rubber having the above characteristics has a relatively low styrene content. Generally, since the structure of styrene is larger than the structure of vinyl, when the content of styrene is low, the hysteresis heat loss due to friction is low, Do.

In addition, the batch-type solution-polymerized styrene-butadiene rubber can be more advantageous in processability and low fuel consumption performance due to its excellent dispersibility because its terminal is substituted with an aminoalkoxyl group having a non-covalent electron pair to improve bonding with a reinforcing filler.

In addition, since the batch-type solution-polymerized styrene-butadiene rubber does not contain an oil, hysteresis is somewhat higher than that of an oil-containing rubber, and the braking performance is also improved.

If the content of the batch-type solution-polymerized styrene-butadiene rubber is less than 50 parts by weight, improvement in the fuel-combustion performance may be poor, and if it exceeds 70 parts by weight, braking performance may be unfavorable.

The continuous solution-polymerized styrene-butadiene rubber is a rubber polymerized by a continuous method and has a styrene content of 30 wt% and a vinyl content of 20 to 40 wt% in butadiene.

The continuous solution-polymerized styrene-butadiene rubber has a glass transition temperature (Tg) of -30 to -50 ° C, a weight average molecular weight of 1,200,000 to 1,700,000 g / mol, and a molecular weight distribution of 1.5 or more.

The continuous solution-polymerized styrene-butadiene rubber may also be substituted with aminoalkoxysilyl groups at the terminals, and the oil may contain 20 to 40 parts by weight of SRAE oil. The SRAE oil content refers to 100 parts by weight of the rubbery component of the continuous solution polymerized styrene-butadiene rubber, and the rubbery component refers to all other components except the oil in the continuous solution-polymerized styrene-butadiene rubber .

The SRAE oil is an oil extracted from the extracted residue of TDAE oil. The total content of PAH (Polycyclic Aromatic Hydocarbon) is 3% by weight or less and can be distinguished from TDAE oil with a kinematic viscosity of 210 or more (210 S SUS). In addition, the SRAE oil may have an aromatic component of 15 to 25 wt%, a naphthene component of 35 to 55 wt%, and a paraffin component of 25 to 45 wt% with respect to the entire SRAE oil.

The continuous solution-polymerized styrene-butadiene rubber may be advantageous in workability and low fuel consumption performance due to its excellent dispersibility with a reinforcing filler by substituting an aminoalkoxysilyl group having a non-covalent electron pair. The styrene-butadiene rubber polymerized by the above- Otherwise, the braking performance can be excellent due to the high hysteresis heat loss due to a large amount of low-molecular substances polymerized by the continuous method. This can be seen as an optimized raw material that balances trade-off performance with low fuel consumption and braking performance.

The continuous solution-polymerized styrene-butadiene rubber may be included in an amount of 20 to 40 parts by weight based on 100 parts by weight of the raw rubber. The content of the continuous solution-polymerized styrene-butadiene rubber is the content of only the rubbery component except the oil. If the content of the continuous solution-polymerized styrene-butadiene rubber is less than 20 parts by weight, the braking performance and the fuel consumption performance improvement effect is insignificant. If the content is more than 40 parts by weight, the processability may be disadvantageous.

The neodymium butadiene rubber (Nd-BR) has a narrow molecular weight distribution and a linear molecular structure as compared with cobalt butadiene rubber (Co-BR) or nickel butadiene rubber, and has a low hysteresis heat loss. In this respect, the neodymium-butadiene rubber preferably has a glass transition temperature (Tg) of -100 to -110 DEG C and a molecular weight distribution of 1.5 to 2.5.

If the content of the neodymium-butadiene rubber is less than 10 parts by weight, abrasion resistance and low fuel consumption performance are disadvantageous. If the amount is more than 20 parts by weight, workability may be deteriorated.

The rubber composition for a tire tread does not use carbon black as a reinforcing filler but uses highly disperse silica alone.

In order to produce a rubber composition for a tire tread suitable for the purpose of the present invention, silica having a nitrogen adsorption amount of 160 to 180 m 2 / g, a CTAB value of 150 to 170 m 2 / g and a DBP oil absorption of 180 to 200 cc / It is preferable to use 70 to 90 parts by weight based on 100 parts by weight of the rubber. When the amount of the silica is less than 70 parts by weight, the braking performance may be poor. When the amount of the silica is more than 90 parts by weight, abrasion resistance and low fuel consumption performance may be disadvantageous.

A silane coupling agent may also be used to improve the dispersibility of the silica. The silane coupling agent includes bis (trialkoxysilylpropyl) polysulfide (TESPD) and bis-3-triethoxysilylpropyltetrasulfide (TESPT) in an alkoxy polysulfide silane compound. TESPD is a mixture of TESPT and carbon black 50 %. The silane coupling agent may be used in an amount of 10 to 20 parts by weight based on 100 parts by weight of the raw material rubber.

In addition, the rubber composition for a tire tread may further include a softening agent for imparting plasticity to rubber and for facilitating processing. As the softener, a total content of polycyclic aromatic hydrocarbons (PAHs) is 3 wt% or less, a kinematic viscosity is 95 (210 S SUS) or higher, an aromatic component in the softener is 15 5 to 10 parts by weight of a softener having a naphthene component of 27 to 37% by weight and a paraffin component of 38 to 58% by weight may be used.

The rubber composition for a tire tread may further comprise a vulcanizing agent, a vulcanization accelerator or an antioxidant. In addition to the above-mentioned composition, various additives such as zinc oxide, stearic acid, and processing aid used in a conventional tire tread composition may be required Of course, it can be used selectively.

The vulcanizing agent may be a sulfur vulcanizing agent. Examples of the sulfur vulcanizing agent include an elemental sulfur or a vulcanizing agent for producing sulfur, for example, amine disulfide or polymer sulfur. The vulcanizing agent may be used in an amount of 1.5 to 2.5 parts by weight based on 100 parts by weight of the raw rubber.

The vulcanization accelerator may be selected from the group consisting of an amine, a disulfide, a guanidine, a thio element, a thiazole, a thiuram, a sulfene amide, Any one selected may be used in an amount of 0.8 to 2.0 parts by weight based on 100 parts by weight of the raw rubber.

The antioxidant may be selected from the group consisting of N- (1,3-dimethylbutyl) -N-phenyl-p-phenylenediamine (6PPD), N-phenyl-n-isopropyl-p-phenylenediamine (3PPD) 4-trimethyl-1,2-dihydroquinone (RD), and combinations thereof may be used in an amount of 1 to 5 parts by weight based on 100 parts by weight of the raw rubber.

The rubber composition for a tire tread can be produced through a conventional two-step continuous manufacturing process. That is, during the finishing step in which the first stage of thermomechanical treatment or kneading and the crosslinking system are mixed at a maximum temperature of 110 to 190 占 폚, preferably at a high temperature of 130 to 180 占 폚, typically less than 110 占 폚, And a second step of mechanical treatment at a low temperature of 40 to 100 DEG C in a suitable mixer, but the present invention is not limited thereto.

The rubber composition for a tire tread is not limited to a tread (a tread cap and a tread base) but may be included in various rubber components constituting the tire. Said rubber components include sidewalls, sidewall inserts, apex, chafer, wire coat or inner liner.

A tire according to another embodiment of the present invention is manufactured using the rubber composition for the tire tread. The method of manufacturing a tire using the rubber composition for a tire tread may be any method conventionally used for manufacturing a tire, and a detailed description thereof will be omitted herein.

The tires may be automobile tires, racing tires, airplane tires, agricultural tires, off-the-road tires, truck tires or bus tires. Further, the tire may be a radial tire or a bias tire, and preferably a radial tire.

The rubber composition for a tire tread of the present invention can improve the performance of a low fuel consumption without deteriorating braking performance on a wet road surface.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily carry out the present invention. The present invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein.

[ Manufacturing example : Preparation of rubber composition]

Rubber compositions for tire treads according to the following Examples and Comparative Examples were prepared using the compositions shown in Table 1 below. The production of the rubber composition was in accordance with the usual production method of the rubber composition.

Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Comparative Example 3 S-SBR (1) 90 80 70 60 50 40 S-SBR (2) 0 10
(3.8) 20
(7.5) 30
(11.3) 40
(15.0) 50
(18.8) BR 10 10 10 10 10 10 Silica 80 80 80 80 80 80 Coupling agent 15 15 15 15 15 15 Processing oil 5 5 5 5 5 5 Antioxidant 6 6 6 6 6 6 Vulcanizing agent 1.5 1.5 1.5 1.5 1.5 1.5 accelerant 2.1 2.1 2.1 2.1 2.1 2.1

week)

(Unit: parts by weight)

1) S-SBR (1) having a styrene content of 25% by weight, a vinyl content of butadiene of 45% by weight, a glass transition temperature (Tg) of -30 占 폚, a weight average molecular weight of 600,000 to 800,000 g / A solution-polymerized styrene-butadiene rubber (SBR) prepared by a batch process in which the molecular weight distribution is 1.1 or less and the terminals are substituted with aminoalkoxysilyl groups,

2) S-SBR (2): a styrene content of 35% by weight, a vinyl content in butadiene of 25% by weight, a glass transition temperature (Tg) of -35 占 폚, Solution-polymerized styrene-butadiene rubber (SBR), SRAE oil extended (content in parentheses is the content of oil) prepared by the continuous process in which the molecular weight distribution is not less than 1.5 and the terminal is substituted with aminoalkoxysilyl group,

3) BR: Butadiene rubber prepared by Neodium catalyst

4) Silica: a precipitated silica having a nitrogen adsorption value of 175 m < 2 > / g and a CTAB value of 160 m &

5) Processed oil: the total content of PAHs component is 3% by weight or less, the kinematic viscosity is 95 (210 S SUS), the aromatic component in the softener is 25% by weight, the naphthene component is 32.5% by weight and the paraffin component is 47.5% by weight oil

[ Experimental Example : Measurement of physical properties of the prepared rubber composition]

The rubber specimens prepared in Examples and Comparative Examples were measured for Mooney viscosity, hardness, 300% modulus and viscoelasticity according to the ASTM regulations. The results are shown in Table 2 below.

Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Comparative Example 3 Mooney viscosity 63 62 64 69 72 80 Hardness (ShoreA) 66 67 67 67 67 68 300% modulus 180 178 183 189 185 182 Fracture energy 253 235 230 216 215 210 0 deg. 0.285 0.386 0.428 0.454 0.476 0.488 60 deg. 0.069 0.072 0.075 0.080 0.084 0.090

1) Mooney viscosity (ML1 + 4 (125 DEG C)) was measured according to ASTM standard D1646.

2) The hardness was measured by DIN 53505.

3) 300% modulus and breaking energy were measured by ISO 37 standard.

4) The viscoelasticity was measured at GHz, G ", and tan δ from -60 ℃ to 60 ℃ under a frequency of 10 Hz at 0.5% strain using an RDS meter.

In Table 2, the Mooney viscosity is a value indicating the viscosity of the unvulcanized rubber, and the lower the numerical value is, the better the workability of the unvulcanized rubber is. The hardness indicates the steering stability. The higher the value, the better the steering stability. The breaking energy represents the energy required when the rubber breaks. The higher the value, the higher the required energy and the better the abrasion performance. 0 ° C tan δ indicates the braking performance on a dry road surface or a wet road surface. The higher the value, the better the braking performance. Further, tan? Of 60 占 폚 indicates the rotational resistance characteristic, and the lower the value, the better the performance.

Treads were prepared from the rubber specimens prepared in the above Examples and Comparative Examples, and 245 / 40ZR19 standard tires including the above-mentioned tread rubber as a semi-finished product were manufactured. The tire was subjected to braking distance and rotation resistance on the wet road surface The fuel-efficiency performance was measured and is shown in Table 3 as a relative ratio.

Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Comparative Example 3 Wet road braking performance 85 95 103 105 108 110 Low fuel consumption performance 123 119 115 108 103 96

Referring to Table 3, it can be seen that in Examples 1 to 3, the fuel-efficiency performance was excellent without lowering the braking performance on the wet road surface, which is a trade-off performance.

As described above, when the rubber polymerized by continuous method with the rubber polymerized by the batch method of the styrene-butadiene rubber substituted with the aminoalkoxysilyl group at the end is used in a binary manner, the braking performance on the wet road surface is lowered Fuel ratio performance without any significant improvement in fuel efficiency. However, when the aminoalkoxysilyl group is substituted at the terminal and the styrene-butadiene rubber polymerized by the continuous method is increased to more than the proper weight portion, the low fuel consumption performance is disadvantageously deteriorated and the processability is also significantly deteriorated.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments, Of the right.

Claims (7)

100 parts by weight of a raw rubber comprising 50 to 70 parts by weight of a batch-type solution-polymerized styrene-butadiene rubber, 20 to 40 parts by weight of a continuous solution-polymerized styrene-butadiene rubber and 10 to 20 parts by weight of neodymium-
70 to 90 parts by weight of a reinforcing filler comprising silica,
Wherein the styrene-butadiene rubber has a styrene content of 20 to 40 wt%, a vinyl content of 30 to 50 wt% in butadiene, a glass transition temperature (Tg) of -20 to 40 DEG C, a weight average molecular weight of 600,000 To 800,000 g / mol, a molecular weight distribution of 1.1 or less, a terminal substituted with an aminoalkoxysilyl group,
Wherein the continuous solution-polymerized styrene-butadiene rubber has a styrene content of 30 to 50 wt%, a vinyl content of butadiene of 20 to 40 wt%, a glass transition temperature (Tg) of -30 to 50 DEG C, 1,200,000 to 1,700,000 g / mol, a molecular weight distribution of 1.5 or more, the terminal is substituted with an aminoalkoxysilyl group,
Wherein the SRAE oil is contained in an amount of 20 to 40 parts by weight based on 100 parts by weight of the rubbery component of the continuous solution polymerized styrene-butadiene rubber,
The SRAE oil is an oil obtained by re-extracting the extraction residue of TDAE oil. The total content of PAH (Polycyclic Aromatic Hydocarbon) is 3 wt% or less, the kinematic viscosity is 210 or more (210 S SUS) Wherein the naphthenic component is 35 to 55% by weight and the paraffinic component is 25 to 45% by weight. delete delete delete The method according to claim 1,
Wherein the neodymium-butadiene rubber has a glass transition temperature (Tg) of -100 to -110 캜 and a molecular weight distribution of 1.5 to 2.5. The method according to claim 1,
Wherein the silica has a nitrogen adsorption amount of 160 to 180 m 2 / g, a CTAB value of 150 to 170 m 2 / g, and a DBP oil absorption of 180 to 200 cc / 100 g. A tire produced by using the rubber composition for a tire tread according to claim 1.