KR101125559B1

KR101125559B1 - Rubber composition for tire tread and tire manufactured by using the same

Info

Publication number: KR101125559B1
Application number: KR1020100118650A
Authority: KR
Inventors: 장수진
Original assignee: 한국타이어 주식회사
Priority date: 2010-11-26
Filing date: 2010-11-26
Publication date: 2012-03-22

Abstract

The present invention relates to a rubber composition for a tire tread and a tire manufactured using the same, which is a continuous rubber having 10 to 30 parts by weight of natural rubber, a styrene content of 35 to 45% by weight, and a vinyl content of butadiene of 20 to 30% by weight. 30 to 50 parts by weight of the solution-polymerized styrene-butadiene rubber and 30 to 50 parts by weight of neodymium butadiene rubber prepared by the method, 80 to 110 parts by weight of silica, and 20 to 40 parts by weight of liquid butadiene rubber Include.
The rubber composition for tire treads can be used as a tread rubber composition for four seasons, while greatly improving the braking performance on ice and snow roads, and also having excellent braking performance on dry and wet roads and low rotational resistance.

Description

RUBBER COMPOSITION FOR TIRE TREAD AND TIRE MANUFACTURED BY USING THE SAME

The present invention relates to a rubber tread rubber composition and a tire manufactured using the same, which greatly improves the braking performance on a snowy road surface and also has excellent braking performance on dry and wet road surfaces and has low rotational resistance and low tread rubber composition for four seasons. It relates to a rubber composition for tire tread that can be used as, and to a tire manufactured using the same.

Recently, as global warming accelerates, snowfall rapidly decreases and snow roads form during the year, but snow is melting and forming wet road conditions such as slush and rain.

Since the properties of the rubber composition required for braking performance on dry or wet roads and snow and snow roads are mutually opposite, if one performance is chosen, the other performance is inevitably disadvantageous.

Therefore, in winter, many people replace with winter tires that have excellent braking performance on the snowy road surface, but the braking performance becomes very disadvantageous when it is not snowing or when the snow melts and gets wet, so the demand for consumers The trend is increasing. In particular, since this is a problem directly related to the stability of automobiles, as a major concern of tire manufacturers, research and development to solve this situation are actively being promoted.

In order to solve this problem, conventionally, by using styrene-butadiene rubber having a high styrene content in the winter tread tire rubber composition, a method of increasing the glass transition temperature of the rubber composition to improve braking performance on dry or wet road surfaces is used. However, as the styrene content is increased, the hardness and modulus of the rubber at a low temperature increase, which causes a problem that the braking performance on the ice snow road is reduced.

In addition, many methods using silica as a reinforcing agent are used. Silica has excellent reinforcement property compared to carbon black, which is excellent in braking performance on dry or wet roads, and has a low temperature dependence at low temperature. Since it is lower than this carbon black, there is an advantageous advantage in braking performance on the ice and snow road surface. However, simply replacing the reinforcing agent from carbon black to silica in the winter tire tread rubber composition does not significantly improve braking performance on wet road surfaces. The improvement of braking performance on wet roads of winter tires with silica is very limited and the proper matching of two contradictory performances to meet consumer demand remains a difficult technical challenge.

SUMMARY OF THE INVENTION An object of the present invention is to provide a rubber composition for tire treads that can be used as a tread rubber composition for four seasons with a great improvement in braking performance on a snowy road surface and also excellent braking performance on dry and wet road surfaces and low rolling resistance.

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

In order to achieve the above object, the rubber composition for a tire tread according to an embodiment of the present invention is 10 to 30 parts by weight of natural rubber, styrene content of 35 to 45% by weight, the vinyl content of butadiene is 20 to 30% by weight 30 to 50 parts by weight of solution-polymerized styrene-butadiene rubber and 30 to 50 parts by weight of neodymium butadiene rubber prepared by the continuous method, 80 to 110 parts by weight of silica, and 20 to 40 parts by weight of liquid butadiene rubber It includes parts by weight.

The liquid butadiene rubber may have a molecular weight of 1,000 to 10,000, a glass transition temperature of -60 to -80 ° C, and a vinyl content of 20 to 30% by weight.

The silica may have a BET surface area of 160 to 180 m ² / g and a DBP oil absorption of 180 to 210 cc / 100 g.

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

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

The tire tread rubber composition includes 100 parts by weight of raw rubber, 80 to 110 parts by weight of silica, and 20 to 40 parts by weight of liquid butadiene rubber.

The raw rubber includes 10 to 30 parts by weight of natural rubber, 30 to 50 parts by weight of solution-polymerized styrene-butadiene rubber and 30 to 50 parts by weight of neodymium butadiene rubber prepared by a continuous method.

The natural rubber is a rubber obtained in nature and its chemical name is polyisoprene.

The solution-polymerized styrene-butadiene rubber prepared by the continuous method is disadvantageous in terms of rotational resistance in comparison with the styrene-butadiene rubber produced by the batch method due to a large amount of low molecular weight material, but has excellent processability and high hysteresis loss. Excellent braking performance on wet or wet roads.

The solution polymerized styrene-butadiene rubber prepared by the continuous method may have a styrene content of 35 to 45 wt% and a vinyl content of butadiene 20 to 30 wt%. The tire tread rubber composition may further improve braking performance on wet road surfaces by using a solution-polymerized styrene-butadiene rubber prepared by a continuous method having the above characteristics together with natural rubber.

The neodymium butadiene rubber (Nd-BR) has a narrower molecular weight distribution than the cobalt butadiene rubber (Co-BR) or nickel butadiene rubber (Ni-BR), and has a low molecular hysteresis due to its linear molecular structure, thereby providing excellent rotational resistance. Excellent characteristics in wear performance.

When the content of the natural rubber is less than 10 parts by weight, the durability of the tread may be disadvantageous, and if it exceeds 30 parts by weight, braking performance may be disadvantageous on wet or dry roads. When the content of the solution-polymerized styrene-butadiene rubber prepared by the continuous method is less than 30 parts by weight, braking performance may be disadvantageous on dry or wet roads, and when it exceeds 50 parts by weight, braking performance and fuel economy on ice and snow roads. Performance can be disadvantageous. If the content of the neodymium butadiene rubber is less than 30 parts by weight, the braking performance and fuel economy performance on the ice and snow road surface may be disadvantageous, when the content of more than 50 parts by weight may be adversely affected on the wet road or dry road surface.

The silica may be included from 80 to 110 parts by weight based on 100 parts by weight of the raw material rubber. When the content of the silica is less than 80 parts by weight, the strength improvement of the rubber may be insufficient and the braking performance of the tire may be reduced. When the content of the silica exceeds 110 parts by weight, wear performance may be reduced.

In the case of using precipitated silica having a BET surface area of 160 to 180 m ² / g and a DBP oil absorption of 180 to 210 cc / 100 g as the silica, it is easy to disperse to improve wear resistance and further improve braking performance on wet road surfaces. You can.

The tire tread rubber composition uses liquid butadiene rubber instead of conventional process oil as a softener. By using the liquid butadiene softener in combination with the raw material rubber and silica composition, the rubber composition for tire treads greatly improves the braking performance on ice and snow roads, and also has excellent braking performance on dry and wet roads and low rolling resistance. It can be suitably used as a tread rubber composition for.

The content of the liquid butadiene rubber is 20 to 40 parts by weight based on 100 parts by weight of the raw material rubber, when the content of the liquid butadiene rubber is less than 20 parts by weight, the mixing of the raw material rubber and silica may not be made smoothly, ice and snow The braking performance improvement on the road surface may not be significant. In addition, when the content of the liquid butadiene rubber exceeds 40 parts by weight, the glass transition temperature of the blended rubber is greatly reduced, which may adversely affect the braking performance on the wet road surface.

The liquid butadiene rubber may have a molecular weight of 1,000 to 10,000, a glass transition temperature of -60 to -80 ° C, and a vinyl content of 20 to 30% by weight. That is, the liquid butadiene rubber is in a liquid state at room temperature because the molecular weight is very small compared to the solid butadiene conventionally used as a raw material rubber, which can be used as a softening agent to smoothly mix the raw material rubber and silica as process oil.

In addition, the liquid butadiene rubber has a lower glass transition temperature than the process oil, thereby lowering the glass transition temperature of the blended rubber, thereby reducing the hardness and modulus of the rubber at low temperatures, thereby greatly improving the braking performance on the snow surface and reducing rolling resistance. .

In addition, the liquid butadiene is a vinyl content of the solid butadiene is less than 2% by weight compared with the high vinyl content may not reduce the braking performance on dry or wet road surface.

The tire tread rubber composition may include a sulfur vulcanizing agent as a vulcanizing agent. As the sulfur vulcanizing agent, a vulcanizing agent for producing elemental sulfur or sulfur, for example, amine disulfide or polymer sulfur may be used, and elemental sulfur may be preferably used.

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 material rubber, and the raw material rubber may be less sensitive to heat and chemically stable as an appropriate vulcanizing effect within the above range.

In addition, the rubber composition for tire tread is a vulcanization accelerator, such as amine (Amine), disulfide, guanidine, thio urea, thiazole, thiuram, sulfene amide and Any one selected from the group consisting of a combination thereof may further include 0.8 to 2.0 parts by weight based on 100 parts by weight of the raw material rubber.

In addition, the rubber composition for tire tread is N- (1,3-dimethylbutyl) -N'-phenyl-p-phenylenediamine (6PPD), N-phenyl-N'-isopropyl-p-phenyl as an anti-aging agent. Any one selected from the group consisting of rendiamine, N, N'-diphenyl-p-phenylenediamine (3PPD), 2,2,4-trimethyl-1,2-dihydroquinoline (RD), and combinations thereof It may further include 1 to 5 parts by weight based on 100 parts by weight of the raw material rubber.

In addition to the above-mentioned composition, the rubber composition for tire tread can be used by selecting various additives, such as zinc oxide, stearic acid, a coupling agent or a processing aid, which are used in a general tire tread rubber composition.

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 step of thermomechanical treatment or kneading at a maximum temperature ranging from 110 to 190 ° C., preferably from 130 to 180 ° C. (called the non-production step) and the crosslinking system are mixed, typically It can be prepared in a suitable mixer using a second step (called a production step) of mechanical treatment at a low temperature of less than 110 ° C., for example 40-100 ° C., but the invention is not limited thereto.

The rubber composition for the tire tread is not limited to the tread (tread cap and tread base), and may be included in various rubber components constituting the tire. Such rubber components include sidewalls, sidewall inserts, apex, chafers, wire coats or innerliners, and the like.

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

The tire may be a passenger car tire, a racing tire, an airplane tire, a farm tire, an off-the-road tire, a truck tire or a bus tire. In addition, the tire may be a radial tire or a bias tire, and is preferably a radial tire.

The rubber composition for tire treads of the present invention can be used as a tread rubber composition for four seasons, while greatly improving the braking performance on a snowy road surface, and also having excellent braking performance on a dry road surface and a wet road surface and low rotational resistance.

Hereinafter, embodiments of the present invention will be described in detail so that those skilled in the art can easily practice the present invention. As those skilled in the art would realize, the described embodiments may be modified in various different ways, all without departing from the spirit or scope of the present invention.

[Production Example: Production of Rubber Composition]

Using a composition as shown in Table 1 below to prepare a rubber composition for tire treads according to the following examples and comparative examples. The rubber composition was prepared according to a conventional method for preparing a rubber composition.

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 Example 2 Example 3 Natural rubber ¹⁾ 20 20 20 20 20 20 20 20 S-SBR (1) ²⁾ 55
40 - - - - - - - S-SBR (2) ³⁾ - 55
40 55
40 55
40 55
40 55
40 55
40 55
40 BR (1) ⁴⁾ 40 40 - - - - - - BR (2) ⁵⁾ - - 40 40 40 40 40 40 Silica ⁶⁾ 100 100 100 100 100 100 100 100 Coupling Agent ⁷⁾ 14 14 14 14 14 14 14 14 Softener (1) ⁸⁾ 30 30 30 - - - - - Softener (2) ⁹⁾ - - - 10 50 20 30 40 Zinc oxide 3 3 3 3 3 3 3 3 Stearic acid One One One One One One One One Anti-aging 2.4 2.4 2.4 2.4 2.4 2.4 2.4 2.4 Vulcanizer 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 accelerant 1.5 1.5 1.5 1.5 1.5 1.5 1.5 1.5 Accelerator (DPG) 2 2 2 2 2 2 2 2

(Unit: parts by weight)

1) Natural rubber: Naturally obtained rubber, its chemical name is polyisoprene

2) S-SBR (1): 38% by weight of styrene, 24% by weight of vinyl in butadiene, solution polymerized styrene-butadiene rubber (3DA parts of TDAE oil extended) prepared by a batchwise method, numerical values in parentheses Is the content of S-SBR excluding oil)

3) S-SBR (2): 38 wt% styrene content, 24 wt% vinyl content in butadiene, solution polymerized styrene-butadiene rubber (TDAE oil 37.5 parts extended, prepared in parentheses) The value is the content of S-SBR excluding oil)

4) BR (1): Nickel butadiene rubber made by Kumho Petrochemical Co., Ltd .; brand name KBR01

5) BR (2): Neodymium butadiene rubber made by Lanxess, trade name CB24

6) Silica: Precipitated silica with BET surface area of 160 to 180 m ² / g and DBP oil absorption of 180 to 210 cc / 100 g

7) Coupling agent: A sulfide silane made by Degussa, trade name Si69

8) Softener (1): Total content of PolyCyclic Aromatic Hydocarbon (PAH) component is 3 wt% or less, kinematic viscosity is 95 (210 ° F. SUS), 25 wt% aromatic component, 32.5 wt% naphthenic component, and Oil having a paraffinic component of 47.5% by weight, trade name Vivatec500

9) Softener (2): Satomer liquid polybutadiene rubber with a molecular weight of 8,000, glass transition temperature of -70 ° C and a vinyl content of 28% by weight.

Experimental Example: Measurement of Physical Properties of Prepared Rubber Composition

The Mooney viscosity, hardness, 300% modulus, viscoelasticity, and the like of the rubber specimens prepared in Examples and Comparative Examples were measured based on ASTM-related regulations, and the results are shown in Table 2 below.

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 Example 2 Example 3 Mooney viscosity 46 50 52 80 52 74 65 58 Hardness (ShoreA) 65 65 65 70 58 66 63 61 300% modulus
(Mpa) 8.0 7.9 8.0 8.7 6.6 8.0 7.4 6.9 -40 ℃ G '
(dyne / ㎠) 1.72E + 09 1.80E + 09 1.76E + 09 1.58E + 09 9.14E + 08 1.34E + 09 1.12 + 09 9.55 + 08 0 ℃ tanδ 0.218 0.222 0.220 0.235 0.209 0.228 0.222 0.216 60 ℃ tanδ 0.150 0.153 0.147 0.145 0.115 0.138 0.132 0.121

Pattern viscosity (ML1 + 4 (125 ° C.)) was measured according to ASTM standard D1646.

Hardness was measured according to DIN 53505

300% modulus was measured according to ISO 37 standard.

-Viscoelasticity was measured G ', G ", tanδ from -60 ℃ to 60 ℃ under 10Hz frequency at 0.5% strain using an RDS meter.

Mooney viscosity in Table 2 is a value indicating the viscosity of the unvulcanized rubber, the lower the value, the more excellent workability of the unvulcanized rubber. Hardness indicates steering stability. The higher the value, the better the steering stability. -40 ℃ G 'shows the braking characteristics on the ice road surface. The lower the value, the better the braking performance. The 0 ℃ tanδ shows the braking performance on the dry or wet road surface. The higher the value, the better the braking performance. . In addition, 60 ° C. tan δ indicates rotational resistance characteristics, and a lower value indicates better performance.

In addition, a tread rubber is made from the rubber composition prepared in Comparative Examples and Examples, and a tire of 205 / 55R16 standard including the tread rubber as a semi-finished product is manufactured. Braking performance and fuel efficiency were measured, and the results are shown in Table 3 as a relative ratio with respect to Comparative Example 1.

Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Example 1 Example 2 Example 3 Dry road braking performance 100 100 99 102 99 101 100 99 Wet road
Braking performance 100 102 102 103 95 102 101 98 Snow surface
Braking performance 100 99 100 103 113 106 108 110 Fuel efficiency 100 98 102 102 109 103 105 107

Referring to Table 2 and Table 3, the solution prepared by the continuous compared to the case of using a solution-polymerized styrene-butadiene rubber prepared by batch (Comparative Example 1) or when using a nickel butadiene rubber (Comparative Example 2) When polymerized styrene-butadiene rubber and neodyne butadiene rubber are used (Comparative Example 3), braking performance is improved on wet roads without deterioration of the braking performance on ice-snow roads. When it is added to 40 parts by weight, it can be seen that the braking performance on the snowy road surface is greatly improved and the fuel efficiency is also greatly improved without deterioration of the braking performance on the dry road surface or wet road surface.

Although the preferred embodiments of the present invention have been described in detail above, the scope of the present invention is not limited thereto, and various modifications and improvements of those skilled in the art using the basic concepts of the present invention defined in the following claims are also provided. It belongs to the scope of rights.

Claims

10 to 30 parts by weight of natural rubber,
30 to 50 parts by weight of a solution-polymerized styrene-butadiene rubber prepared by a continuous process having a styrene content of 35 to 45% by weight and a vinyl content of 20 to 30% by weight in butadiene, and
30 to 50 parts by weight of neodymium butadiene rubber
100 parts by weight of raw rubber, including
80 to 110 parts by weight of silica, and
20 to 40 parts by weight of liquid butadiene rubber
Rubber composition for a tire tread comprising a.

The method of claim 1,
The liquid butadiene rubber has a molecular weight of 1,000 to 10,000, the glass transition temperature is -60 to -80 ℃, the vinyl content is a rubber composition for tire treads 20 to 30% by weight.

The method of claim 1,
The silica has a BET surface area of 160 to 180m ² / g, DBP oil absorption of 180 to 210cc / 100g rubber composition for tire tread.

A tire manufactured using the rubber composition for tire tread according to any one of claims 1 to 3.