KR20140058171A - 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 which comprises 100 wt% of raw material rubber and 5-10 wt% of liquefied butadiene gel in which a terminal end is modified to siloxane; and a tire manufactured by using the same. The rubber composition for a tire thread improves an economical function and a braking function on dried roads and wet roads.

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]

TECHNICAL FIELD The present invention relates to a rubber composition for a tire tread and a tire produced using the same, and relates to a rubber composition for a tire tread applicable to passenger cars and SUVs, and a tire manufactured using the same.

In the area where snowfall is large due to global warming, snow has melted down to form ice sheets, but snow is now melted to form wet road surfaces such as slush or rain.

In addition, the economy is shifting to an economic system that prioritizes depletion of fossil fuels and eco-friendliness, so that fuel-efficiency performance is particularly demanded.

In order to solve such a problem, a method of improving the braking performance on a dry road surface or a wet road surface by raising the glass transition temperature of a rubber composition by using a styrene-butadiene rubber having a high styrene content in a rubber composition for a tire tread has been used. However, as the styrene content increases, the hardness and modulus of the rubber at low temperatures increase, so that the braking performance on the ice and snow surface is lowered and the fuel consumption performance is poor.

Therefore, there is a great demand for a rubber composition for a tire tread which is excellent in low fuel consumption performance, braking performance on a dry road surface and a wet road surface, and which can be applied to all seasons by maintaining the existing low temperature performance.

Korean Patent Registration No. 0782975 (Registered on November 30, 2007)

An object of the present invention is to provide a rubber composition for a tire tread capable of improving braking performance on a dry road surface and a wet road surface while improving a low fuel consumption performance.

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

In order to achieve the above object, the rubber composition for a tire tread according to an embodiment of the present invention includes 100 parts by weight of a raw rubber and 5 to 10 parts by weight of a liquid butadiene gel having a siloxane terminal.

Both ends of the liquid butadiene gel may be modified with the siloxane.

The liquid polybutadiene gel may be a terminal modified with _{3 -Si (OCH 2 CH 3)} .

The liquid butadiene gel may have a glass transition temperature (Tg) of -60 to -30 占 폚, a vinyl content of 60 to 70% by weight, and a number average molecular weight of 2000 to 8000 g / mol.

Wherein the raw material rubber comprises 35 to 45 parts by weight of a first solution-polymerized styrene-butadiene rubber having a styrene content of 20 to 30% by weight and a vinyl content in butadiene of 50 to 70% by weight, a styrene content of 30 to 40% 35 to 45 parts by weight of a second solution polymerized styrene-butadiene rubber having a vinyl content of 20 to 30% by weight, and 10 to 30 parts by weight of a nickel butadiene rubber.

The rubber composition for a tire tread may further include 75 to 90 parts by weight of silica having a nitrogen adsorption specific surface area of 160 to 170 m2 / g and a CTAB adsorption specific surface area of 150 to 180 m2 / 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 one embodiment of the present invention includes 100 parts by weight of raw rubber and 5 to 10 parts by weight of a liquid butadiene gel having a terminal modified with siloxane. The rubber composition for a tire tread has a low fuel consumption performance and excellent braking performance on a dry road surface and a wet road surface by using a liquid butadiene gel whose terminal is modified with siloxane, Applicable.

Wherein the raw material rubber comprises 35 to 45 parts by weight of a first solution-polymerized styrene-butadiene rubber having a styrene content of 20 to 30% by weight and a vinyl content in butadiene of 50 to 70% by weight, a styrene content of 30 to 40% 35 to 45 parts by weight of a second solution polymerized styrene-butadiene rubber having a vinyl content of 20 to 30% by weight, and 10 to 30 parts by weight of a nickel butadiene rubber.

The styrene-butadiene rubber may be prepared by a continuous process. Generally, solution-polymerized styrene-butadiene rubber can be prepared by continuous and batch processes. The solution-polymerized styrene-butadiene rubber produced by the continuous process is disadvantageous in terms of rotational resistance as compared with the solution-polymerized styrene-butadiene rubber produced by the batch process because it contains a large amount of a low molecular weight material but has excellent processability, and hysteresis loss Is excellent in braking performance on a dry road surface or a wet road surface.

The first styrene-butadiene rubber having a styrene content of 20 to 30% by weight and a vinyl content of 50 to 70% by weight in the butadiene, a styrene content of 30 to 40% by weight and a vinyl content in butadiene of 20 to 30% % Styrene-butadiene rubber is used in combination, the effect obtained by using the styrene-butadiene rubber produced by the continuous process is maximized.

The first or second styrene-butadiene rubber may be included in an amount of 35 to 45 parts by weight based on 100 parts by weight of the starting rubber. If the content of the first or second styrene-butadiene rubber is less than 35 parts by weight, the braking performance on a wet road surface may be deteriorated. If the content of the first or second styrene-butadiene rubber is more than 45 parts by weight, braking performance on the ice and snow surface may be deteriorated.

The nickel butadiene rubber may be included in an amount of 10 to 30 parts by weight based on 100 parts by weight of the raw material rubber. If the content of the nickel butadiene rubber is less than 10 parts by weight, the braking performance and the abrasion resistance on the ice and snow surface may be deteriorated. If the content is more than 30 parts by weight, the braking performance on the wet road surface may be deteriorated.

As the end of the liquid butadiene gel is modified into siloxane, the dispersibility of the silica as a reinforcing filler is improved due to the reaction of the siloxane, the modulus is increased, the speed of spreading to the surface of the vulcanized rubber is low, It plays a role. To this end, it is more preferable that both ends of the liquid butadiene gel are modified with the siloxane.

The siloxane-modified group may be specifically -Si (OCH ₂ CH ₃ ) ₃ , and the liquid-phase butadiene gel has a glass transition temperature (Tg) of -60 to -30 ° C., a vinyl content of 60 to 70% And a number average molecular weight of 2,000 to 8,000 g / mol. In this case, since the siloxane transformer chemically bonds with the rubber through coupling, hysteresis at a high temperature range (50 to 80 ° C) is lowered, and the rotation resistance is also lowered.

The liquid butadiene gel may be included in an amount of 5 to 10 parts by weight based on 100 parts by weight of the raw rubber. When the content of the liquid butadiene gel is less than 5 parts by weight, the effect of improving the braking performance and the low fuel consumption performance on the wet road surface is insignificant. When the amount is more than 10 parts by weight, the workability is deteriorated and the braking performance on the ice- The adverse effect of disadvantage occurs.

The rubber composition for a tire tread may further comprise silica as a reinforcing filler.

The silica may have a nitrogen adsorption specific surface area of 160 to 170 m2 / g and a CTAB adsorption specific surface area of 150 to 180 m2 / g. When the silica is used, the effect according to the present invention can be further improved.

The silica may be included in an amount of 75 to 90 parts by weight based on 100 parts by weight of the raw rubber. When the content of the silica is less than 75 parts by weight, the reinforcing property is lowered and the braking performance and handling performance on a wet road surface may be deteriorated. If the content of the silica is more than 90 parts by weight, braking performance and abrasion resistance on the ice- have.

Meanwhile, the rubber composition for a tire tread may further include a silane coupling agent, a softening agent, a vulcanizing agent, a vulcanization accelerator, and an antioxidant.

The silane coupling agent is used for improving the dispersibility of the silica and the chemical bonding with the rubber. The bis (trialkoxysilylpropyl) polysulfide (TESPD) and the bis-3-triethoxy Silyl propyl tetrasulfide (TESPT) and the like can be used. The silane coupling agent may be used alone or in the form of a commercially available product blended with 50 wt% of carbon black.

The silane coupling agent may be included in an amount of 10 to 20 parts by weight based on 100 parts by weight of the raw rubber. When the content of the coupling agent is within the above range, the coupling efficiency can be maximized.

The working oil used as the softening agent preferably has a total content of poly-cyclic aromatic hydrocarbon (PAH) components of 3 wt% or less and a kinematic viscosity of 75 or more (100 캜, cST (mm ² / s) A TDAE oil having 20 to 30% by weight of an aromatic component, 25 to 40% by weight of a naphthene component and 40 to 55% by weight of a paraffin component can be preferably used.

The vulcanizing agent is preferably a sulfur vulcanizing agent. Examples of the sulfur vulcanizing agent include a vulcanizing agent which produces elemental sulfur or sulfur such as amine disulfide and polymer sulfur, and elemental sulfur is preferably used. The vulcanizing agent may be included in an amount of 1.5 to 2.5 parts by weight based on 100 parts by weight of the raw rubber. When the content of the vulcanizing agent is within the above range, an adequate balance of braking performance, abrasion resistance and rotational resistance can be achieved by forming appropriate cross-linking density.

As the vulcanization accelerator, amines, disulfides, guanidine, thio elements, thiazole, thiuram, sulfene amide and the like can be used.

The vulcanization accelerator may be contained in an amount of 0.8 to 2.0 parts by weight based on 100 parts by weight of the raw rubber. When the content of the vulcanization accelerator is within the above range, an appropriate crosslinking density can be formed.

Examples of the antioxidant include N- (1,3-Dimethybytyl) -N-phenyl-p-phenlenediamine (6PPD), N-phenyl-n-isopropyl-phenylenediamine (RD) may be used.

The antioxidant may be included in an amount of 1 to 5 parts by weight based on 100 parts by weight of the raw rubber. When the content of the antioxidant is within the above range, the effect of preventing aging is maximized.

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, SUV 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 braking performance on a dry road surface and a wet road surface while improving a low fuel consumption performance.

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.

division Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 Example 3 S-SBR (1) ¹⁾ 40
(15) 40
(15) 40
(15) 40
(15) 40
(15) 40
(15) S-SBR (2) ²⁾ 40
(15) 40
(15) 40
(15) 40
(15) 40
(15) 40
(15) BR ^{3 )} 20 20 20 20 20 20 Silica ^{4 )} 80 80 80 80 80 80 Coupling agent 12 12 12 12 12 12 Process oil ^{5 )} 8 - - - - - Liquid butadiene gel ^{6 )} - 3 13 5 8 10 Zinc oxide 3 3 3 3 3 3 Stearic acid One One One One One One Antioxidant ^{7 )} 2.4 2.4 2.4 2.4 2.4 2.4 Processing aid 2 2 2 2 2 2 Vulcanization ^{8 )} 1.5 1.5 1.5 1.5 1.5 1.5 Accelerator ^{9 )} 1.5 1.5 1.5 1.5 1.5 1.5 Accelerator ^{10 )} 2 2 2 2 2 2

(week)

(Unit: parts by weight)

1) S-SBR (1): Continuous solution polymerized styrene-butadiene rubber having a styrene content of 20 to 30% by weight and a vinyl content of 50 to 70% by weight, TDAE Oil 37.5 parts by weight (content in parentheses is Content)

2) S-SBR (2): continuous solution polymerized styrene-butadiene rubber having a styrene content of 30 to 40% by weight and a vinyl content of 20 to 30% by weight, 37.5 parts by weight of TDAE oil extended Content)

3) BR: Nickel-butadiene rubber

4) Silica: silica having a nitrogen adsorption specific surface area of 160 to 190 m 2 / g and a CTAB adsorption specific surface area of 150 to 180 m 2 / g

5) Processing oil: H & R Low PAH (PolyCyclic Aromatic Hydocarbo) oil

6) the liquid butadiene gel: glass transition temperature (Tg) is -60 to -30 ℃, and a vinyl content of 60 to 70% by weight, and both terminals modified with a -Si (OEth) _3, represented by the formula (1) Liquid butadiene gel

[Chemical Formula 1]

7) Anti-aging agent: 6PPD (trade name)

8) Vulcanizing agent: Oil treated Sulfur

9) Accelerator: CZ (trade name)

10) Accelerator (DPG): DPG (trade name)

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

The physical properties of the rubber specimens prepared in Examples and Comparative Examples were measured and the results are shown in Table 2 below.

Properties Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 Example 3 Mooney viscosity ^{1 )} 90 92 90 90 88 89 Hardness (ShoreA) ^{2 )} 64 64 66 66 68 68 200%
Modulus (Mpa) ^{3 )} 9 8.8 15 9.5 13 14 Viscoelastic
Index ^{4 )} -40 ° C G ' 100 100 85 102 106 99 0 deg. 100 101 115 103 119 119 60 deg. 100 102 111 105 121 115

Company

* Comparing Example 1 with Index 100 (low index <Index 100 <glass)

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

2) The hardness was measured by DIN 53505

3) The 200% modulus was measured according to the 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.

5) In Table 2, the Mooney viscosity indicates the viscosity of the unvulcanized rubber, and the lower the numerical value, the better the workability of the unvulcanized rubber. The hardness indicates the steering stability. The higher the value, the better the steering stability. -40 ° C G 'indicates the braking characteristics on the ice and snow surface, and 0 ° tan δ indicates the braking characteristics on the dry or wet road surface. Further, tan? Of 60 占 폚 indicates the rotational resistance characteristic, and the lower the value, the better the performance.

Treads were made with the rubber composition prepared in the above Comparative Examples and Examples, tires of the 225 / 45R17 standard including the tread as a semi-finished product were manufactured, and the braking distance on the dry road surface, wet road surface, The results are shown in Table 3 based on Comparative Example 1.

Category (Index) Comparative Example 1 Comparative Example 2 Comparative Example 3 Example 1 Example 2 Example 3 Dry road braking distance 100 100 104 103 109 105 Wet road braking distance 100 101 108 102 114 110 Ice and snow road surface braking distance 100 102 95 102 105 103 Rotation resistance 100 102 108 105 113 114

* Comparing Example 1 with Index 100 (low index <Index 100 <glass)

Referring to Tables 2 and 3, when the liquid butadiene gel is added in an amount of 5 to 10 parts by weight, braking performance on dry and wet road surfaces is significantly improved without significantly lowering braking performance on ice and snow surface, The resistance is also greatly improved.

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 raw rubber, and
And 5 to 10 parts by weight of a liquid butadiene gel having a terminal modified with siloxane. The method according to claim 1,
Wherein the liquid-phase butadiene gel has both ends modified with the siloxane. The method according to claim 1,
The liquid gel is terminated butadiene is -Si (OCH ₂ CH ₃₎ to the tire tread rubber composition for a modified _3. The method according to claim 1,
Wherein the liquid-phase butadiene gel has a glass transition temperature (Tg) of -60 to -30 占 폚, a vinyl content of 60 to 70% by weight, and a number average molecular weight of 2000 to 8000 g / mol. The method according to claim 1,
Wherein the raw material rubber comprises 35 to 45 parts by weight of a first solution-polymerized styrene-butadiene rubber having a styrene content of 20 to 30% by weight and a vinyl content of 50 to 70% by weight in butadiene,
35 to 45 parts by weight of a second solution-polymerized styrene-butadiene rubber having a styrene content of 30 to 40% by weight and a vinyl content of 20 to 30% by weight in butadiene, and
10 to 30 parts by weight of a nickel butadiene rubber
&Lt; / RTI &gt; The method according to claim 1,
Wherein the rubber composition for a tire tread further comprises 75 to 90 parts by weight of silica having a nitrogen adsorption specific surface area of 160 to 170 m2 / g and a CTAB adsorption specific surface area of 150 to 180 m2 / g. A tire produced by using the rubber composition for a tire tread according to any one of claims 1 to 6.