KR102504283B1 - Tread compound composition for tire and tire comprising the same - Google Patents

Abstract

The present invention relates to a rubber composition for tire tread comprising raw rubber and a reinforcing filler, wherein the raw rubber comprises natural rubber and anionic polymerized butadiene rubber, and a tire manufactured using the same.

Description

Rubber composition for tire tread and tire manufactured using the same {TREAD COMPOUND COMPOSITION FOR TIRE AND TIRE COMPRISING THE SAME}

The present invention relates to a rubber composition for tire tread for producing a tread of a truck tire or bus tire, comprising as raw material rubber natural rubber and butadiene rubber produced by anionic polymerization having a silica functional group, By including the rubber composition for tire tread in a truck tire or bus tire, low fuel consumption performance and braking performance on a wet road surface are improved, and at the same time, the rubber composition for a tire tread containing carbon black has wear resistance equivalent to that of a rubber composition for tire tread. It relates to a rubber composition for tire tread.

As EU labeling and automobile manufacturers' wet road braking performance and low fuel consumption performance are required for truck/bus tires, it is necessary to improve not only abrasion performance but also vehicle fuel efficiency and wet road braking performance.

In the case of tires for trucks and buses, since they are driven under high load conditions, the durability and abrasion performance of the tires are important. Accordingly, natural rubber or natural rubber and neodymium butadiene rubber and carbon with small particles and high surface area are used as reinforcing fillers. Black rubber composition is being developed and applied.

In order to improve braking performance and low fuel consumption performance on wet roads, it is easiest to replace carbon black, a filler with high heat generation, with silica. However, when silica is used instead, there is a problem that wear performance may be deteriorated because the affinity between natural rubber and silica is very low.

Therefore, it is necessary to prepare a composition in which a rubber component capable of improving affinity with silica is applied in a certain ratio with natural rubber. In order to improve the dispersibility of silica, there is a method of applying a rubber component having a modified group introduced at the end of the polymer.

In the case of neodymium butadiene rubber (Nd-BR) prepared through catalytic polymerization used in conventional rubber compositions, it is difficult to introduce a modifier and increase the modification rate of functional groups during the polymerization process. However, in the case of butadiene rubber produced through anionic polymerization, it is easy to introduce a modifier due to polymerization characteristics, and this modifier can contribute to improving low fuel consumption performance.

In order to solve the above-mentioned problems, the inventors of the present invention have repeated numerous experiments and studies, and, at the end, the introduction of the transformer is easy and the modification rate is high, maintaining the wear resistance performance against the content, and the trade-off of tire properties A rubber composition for tire treads containing a novel rubber component having improved braking performance and low fuel consumption performance on a wet road surface has been completed.

An object of the present invention is to provide a rubber composition for tire tread with improved low fuel consumption performance and improved braking performance on wet road surfaces while maintaining excellent wear resistance so that it can be used for truck tires or bus tires.

The present invention replaces carbon black, which is conventionally added to improve or maintain wear resistance, and uses anionic polymerization with a silica-affinity functional group to prevent the wear resistance from deteriorating when silica is added as a reinforcing filler. An object of the present invention is to provide a rubber composition for tire treads comprising a functional butadiene rubber.

Another object of the present invention is to provide a tire with improved low fuel consumption performance and improved braking performance on a wet road while maintaining abrasion resistance equivalent to that of conventional truck tires and bus tires.

The rubber composition for tire tread according to the present invention for solving the above problems is

A rubber composition for a tire tread comprising raw rubber and a reinforcing filler, wherein the raw rubber includes natural rubber and anionic polymerized butadiene rubber.

In the present invention, the anionic polymerized butadiene rubber may include a silica-affinity functional group, and in detail, the silica-affinity functional group is selected from the group consisting of alkoxysilane-based, amine-based, carboxyl-based, hydroxy-based, and ester-based functional groups. There may be more than one selected.

In the present invention, the anionic polymerization butadiene rubber having a silica-affinity functional group may have a vinyl content of 10 to 40%.

In the present invention, the raw material rubber may include 60 to 90 parts by weight of the natural rubber and 10 to 40 parts by weight of the anionic polymerized butadiene rubber having the silica-affinity functional group.

In the present invention, the reinforcing filler includes at least one selected from the group consisting of carbon black and silica, and the reinforcing filler may be included in an amount of 10 to 70 parts by weight based on 100 parts by weight of the raw rubber.

In the present invention, the reinforcing filler includes carbon black and silica,

The carbon black may be included in 1 to 9 parts by weight based on 100 parts by weight of the raw rubber, and the silica may be included in 1 to 69 parts by weight based on 100 parts by weight of the raw rubber.

The present invention also provides a tire comprising the above-described rubber composition for tire tread.

Specifically, the tire may be a truck tire or a bus tire.

Using the rubber composition for tire tread according to the present invention, a truck tire or a bus tire with improved low fuel consumption performance and braking performance on a wet road surface can be manufactured.

The rubber composition for tire tread according to the present invention has excellent wear resistance even when carbon black is replaced with silica as a reinforcing filler.

In addition, the present invention has an effect of excellent physical properties compared to the content and easy manufacturing, compared to the case of introducing a conventional neodymium butadiene rubber because introduction of a silica-affinity functional group is easy and the modification rate is high.

Hereinafter, each configuration of the present invention will be described in more detail so that those skilled in the art can easily practice it, but this is only one example, and the scope of the present invention is Not limited.

A rubber composition for tire tread according to the present invention is a rubber composition for tire tread comprising raw rubber and a reinforcing filler, wherein the raw rubber includes natural rubber and functional butadiene rubber produced by anionic polymerization.

In order to improve the wear resistance of tires, it is necessary to add a high content of carbon black. Since trucks and buses are generally operated under high load conditions, a high content of carbon black is included in order to obtain excellent wear resistance so that the tire is prevented from being worn even under high load conditions.

In recent years, as environmental regulations have been strengthened in each country due to global warming, the demand for improved fuel efficiency performance of truck tires and bus tires has increased. In addition, when a traffic accident occurs in trucks and buses, the scale of the accident is large and the possibility of causing a secondary accident is high. To prevent this, truck and bus tires with improved braking performance on wet or icy roads are As the demand for tire tread increases, a rubber composition for tire treads having excellent abrasion resistance, low fuel consumption performance and improved braking performance on a wet road surface has been completed.

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

[raw rubber]

As the raw material rubber according to the present invention, a functional butadiene rubber prepared by anionic polymerization in an amount of 10 to 40 parts by weight and natural rubber in an amount of 90 to 60 parts by weight may be used. It is preferable to use 25 to 35 parts by weight of the prepared functional butadiene rubber and 65 to 75 parts by weight of natural rubber.

More specifically, the anionic polymerized butadiene rubber has a silica-affinity functional group.

When the content of anionic polymerized butadiene rubber is added in a small amount than the above content, there is a problem in that the effect of improving the dispersibility of silica is insignificant, and when added in an excessive amount than the above content, there is a problem in that wear resistance performance is lowered .

More specifically, the anionically polymerized butadiene rubber may have a structure in which a silica-affinity functional group is substituted at the terminal of the conventional butadiene rubber by being prepared by a polymerization method different from that of conventional butadiene rubber, and the silica-affinity functional group is specifically , It may be at least one selected from the group consisting of alkoxysilane-based, amine-based, carboxy-based, hydroxy-based, and ester-based functional groups.

The anionic polymerized butadiene rubber may be, for example, a compound having a structure represented by Chemical Formula 1 below.

[Formula 1]

In Formula 1,

R is any one selected from the group consisting of alkoxysilane-based, amine-based, carboxy-based, hydroxy-based, and ester-based functional groups.

The exemplary compound of Formula 1 as described above can be prepared by reacting 1,3-butadiene with a silica-affinity functional group after obtaining a polymer of 1,3-butadiene in a solution state through an anion activated using an alkyl lithium polymerization initiator.

The anionic polymerized butadiene rubber may have a molecular weight of 500,000 g/mol to 700,000 g/mol. The n is a natural number and can be variously modified within a range satisfying the molecular weight.

For example, R in Chemical Formula 1 is an alkoxysilane, and may be a butadiene rubber compound in which an alkoxysilane-based silica-affinity functional group such as triethoxysilane is substituted at the terminal. However, this is only an example and is not limited thereto.

The anionic polymerized butadiene rubber may have a vinyl content of 10 to 40%. Preferably, it may be 15 to 35%, and when the vinyl content is less than the above content, there is a problem that low fuel consumption performance may be reduced, and when the vinyl content is higher than the above content, the glass transition temperature of the rubber composition is increased. There is a problem that the wear resistance performance may decrease as it rises.

In the present invention, anionic polymerization means a polymerization reaction in which an anion is generated using an anionic polymerization initiator and combined with a monomer to proceed, in particular, organometallic compounds or Grignard reagents The polymerization reaction proceeds by forming a monomeric anion using

When butadiene rubber is prepared by the anionic polymerization method as described above, a silica-affinity functional group is introduced at the end of the butadiene rubber. That is, anionic polymerization butadiene rubber refers to a terminal-modified butadiene rubber having a form in which a silica-affinity functional group is introduced at the terminal of the butadiene rubber.

The natural rubber is a general term for rubber that can be obtained from nature, and the country of origin is not limited. Both general natural rubber and modified natural rubber can be used. It mainly includes cis-1,4-polyisoprene, but is not necessarily limited thereto, and includes trans-1,4-polyisoprene. Natural rubber can also be used.

The modified natural rubber refers to a product obtained by modifying or refining the general natural rubber. For example, the modified natural rubber may include epoxidized natural rubber (ENR), deproteinized natural rubber (DPNR), hydrogenated natural rubber, and the like.

[Reinforcing filler]

The reinforcing filler according to the present invention includes at least one selected from the group consisting of carbon black and silica, and the content thereof is preferably 10 to 70 parts by weight based on 100 parts by weight of the raw rubber.

The reinforcing filler is a component added to impart reinforcing properties to a tire, and among these, carbon black is added to improve tire abrasion performance and chip-cut performance, but is a component of raw rubber with carbon black. Due to the difference in affinity, it was not uniformly dispersed in the rubber composition, so there was a problem that the wear performance and chip cutting performance were not greatly improved compared to the amount of carbon black added. When carbon black is excessively added to improve this, there is a problem of low fuel consumption performance.

In order to solve this problem, in the present invention, it is preferable to include anionic polymerized butadiene rubber as the raw material rubber together with the configuration in which the reinforcing filler includes both carbon black and silica.

When the reinforcing filler includes carbon black and silica, the carbon black is included in an amount of 1 to 9 parts by weight based on 100 parts by weight of the raw rubber, and the silica is contained in an amount of 1 to 69 parts by weight based on 100 parts by weight of the raw rubber. may be included as a part.

In particular, when the reinforcing filler contains both carbon black and silica, it has an effect of improving braking performance and low fuel consumption performance on wet roads, and when carbon black is added in a smaller amount than the above content, truck tires However, there is a problem of not having a level of wear resistance suitable for use in bus tires, and when carbon black is added in excess of the above content, there is a problem in that the degree of improvement in braking performance and low fuel consumption performance on wet roads is insignificant. .

The silica may have a nitrogen adsorption specific surface area per gram (N ₂ SA) of 100 to 180 m ² /g and a CTAB (Cetyl Trimethyl Ammonium Bromide) adsorption specific surface area of 110 to 170 m ² /g, It is not limited to this.

If the nitrogen adsorption specific surface area of the silica is less than 100 m ² /g, reinforcing performance by the silica filler may be disadvantageous, and if it exceeds 180 m ² /g, processability of the rubber composition may be disadvantageous. In addition, if the CTAB adsorption specific surface area of the silica is less than 110 m ² /g, reinforcing performance by silica as a filler may be disadvantageous, and if it exceeds 170 m ² /g, processability of the rubber composition may be disadvantageous.

As the silica, those prepared by a wet method or a dry method may be used, and as commercially available products, Ultrasil VN3, 7000GR (Evonik Co.), Z1165MP, Z195MP (Solvay Co.), and the like may be used.

In addition, the carbon black may have a nitrogen adsorption specific surface area per gram (N ₂ SA) of 30 to 300 m ² /g, and an oil absorption of n-dibutyl phthalate (DBP) of 60 to 180 cc/100g However, the present invention is not limited thereto.

If the nitrogen adsorption specific surface area of the carbon black exceeds 300 m ² /g, processability of the rubber composition for a tire may be disadvantageous, and if it is less than 30 m ² /g, reinforcing performance by carbon black as a filler may be disadvantageous. In addition, if the DBP oil absorption amount of the carbon black exceeds 180 cc/100g, the processability of the rubber composition may deteriorate, and if the DBP oil absorption amount is less than 60 cc/100g, the reinforcing performance by carbon black as a filler may deteriorate.

Representative examples of the carbon black include N110, N121, N134, N220, N231, N234, N242, N293, N299, S315, N326, N330, N332, N339, N343, N347, N351, N358, N375, N539, N550, N582 , N630, N642, N650, N683, N754, N762, N765, N774, N787, N907, N908, N990 or N991.

Meanwhile, the rubber composition for tire tread according to the present invention may optionally further include compounding agents such as a vulcanization agent, a vulcanization accelerator, a softener, an antiaging agent, and an adhesive. Any of the various additives may be used as long as they are commonly used in the field to which the present invention belongs, and their contents are not particularly limited as they depend on the compounding ratio used in conventional rubber compositions for tire treads.

The present invention also provides a tire manufactured using the rubber composition for tire tread according to the present invention.

The tire is particularly suitable for use as a truck tire or a bus tire to meet the object of the present invention. Also, the tire may be a radial tire or a bias tire, and is preferably a radial tire.

Hereinafter, an embodiment of the present invention will be described in detail so that those skilled in the art can easily practice it, but this is only one example, and the scope of the present invention is Not limited.

[Production Example: Preparation of Rubber Composition for Tire Tread]

Rubber compositions according to Examples and Comparative Examples were prepared with the compositions shown in Table 1 below. The rubber composition was prepared by a conventional rubber composition manufacturing method.

(unit: parts by weight) Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Example 4 Anionic Polymerization Butadiene Rubber ¹⁾ - - 10 20 30 30 Natural rubber rubber ²⁾ 70 70 90 80 70 70 Neodymium butadiene rubber ³⁾ 30 30 - - - - Silica ⁴⁾ - 50 50 50 50 50 carbon black ⁵⁾ 53 3 3 3 3 3 Silane coupling agent TESPT ⁶⁾ - 5 5 5 5 5 softener ⁷⁾ - 3 3 3 3 3 zinc oxide ⁸⁾ 3 3 3 3 3 3 stearic acid ⁹⁾ 1.5 1.5 1.5 1.5 1.5 1.5 Antioxidants ¹⁰⁾ 1.0 1.0 1.0 1.0 1.0 1.0 Vulcanization accelerator ¹¹⁾ 1.6 1.6 1.6 1.6 1.6 1.6 sulfur ¹²⁾ 1.8 1.8 1.8 1.8 1.8 1.8 1) The vinyl content of the rubbers applied in Examples 1, 2, and 3 was 10%
Example 4 Vinyl content of applied rubber 20%
Functional butadiene rubber having a silica-affinity functional group prepared by anionic polymerization having a structure of Formula 1 below and having a molecular weight of 500,000 g/mol to 700,000 g/mol
2) STR20
3) Buna CB24 (Aranseo)
4) Zeosil 195MP (Solvay)
5) HP130
6) Si69 (Evonik)
7) TDAE Oil
8) Zinc oxide (Hanil Chemical Industry)
9) Stearic acid (LG)
10) N-1,3-dimethylbuthyl-N-phenyl-p-phenylenediamine (Lanxess)
11) N-cyclohexyl-2-benzothiazylsulfenamide (Lanxess)
12) Ground sulfur (Miwon Corporation)

[Formula 1]

[Experimental Example: Measurement of Physical Properties of 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 Example 1 Example 2 Example 3 Example 4 unvulcanized physical properties ML1+4
(100℃) 70 75 81 78 88 86 Hardness
(Shore A) 64 67 69 69 70 70 Seal
Properties 300% modulus
(kgf/cm²) 120 121 119 124 139 135 Elongation (%) 513 566 501 492 487 488 tensile strength
(kgf/cm²) 275 294 280 277 266 270 viscoelasticity 0℃ G''(E+05)
(Index %) 6.8
(100) 7.7
(114) 7.9
(116) 8.2
(121) 9.5
(140) 10.3
(151) 60℃ tanδ
(Index%) 0.105
(100) 0.105
(100) 0.098
(107) 0.093
(113) 0.077
(136) 0.082
(128) Wear resistance performance (Index %) 100 70 99 98 103 96

(1) Mooney viscosity (ML1+4, 100 ℃): obtained using a Mooney MV2000 (Alpha Technology) instrument at a large rotor, preheating for 1 minute, rotor operating time for 4 minutes, and temperature of 100 ℃.

(2) Tensile properties: Hardness was measured using a Shore A durometer, and tensile properties were measured using an Instron tester according to the ASTM D412 test method.

(3) Viscoelastic properties: Measured with a temperature sweep from -100℃ to 80℃ under the conditions of 10Hz and 0.5% static strain using an ARES tester. At this time, the higher the 0°C G″ value, the better the braking performance on a wet road surface, and the lower the 60°C tanδ value, the lower the rolling resistance performance.

(4) Abrasion resistance performance: After measuring the amount of abrasion using a LAT-100 abrasion tester in order to predict abrasion resistance performance, Comparative Example 1 was set as 100 and expressed as an index based on this. The higher the value, the better the wear resistance performance.

The higher the hardness and 300% modulus, the better the tensile properties. Comparing the tensile strength of Examples 3 and 4 with Comparative Examples 1 and 2, it was confirmed that Examples 3 and 4 had excellent physical properties.

The higher the G″ at 0°C, the better the braking performance on a wet road. As in Comparative Example 1, when the filler contained only carbon black, it was confirmed that the braking performance on a wet road was inferior to that of Comparative Example 2 in which silica was also used. Examples 1, 2, 3 and 4 including anionic polymerized butadiene rubber having a silica-affinity functional group show better braking performance on a wet road than Comparative Example 2.

In the case of low fuel consumption performance, the rubber specimens of Examples 3 and 4 showed the best among all rubber specimens, and in the case of abrasion resistance, Examples 1, 2 and 3 showed equivalent performance.

In the case of Example 4, as the anionic polymerized butadiene rubber contains anionic polymerized butadiene rubber having a high vinyl content, the glass transition temperature of the rubber composition is increased, and thus the wear resistance is relatively lower than that of Example 3, but the low fuel consumption performance and wet It was confirmed that the braking performance on the road surface was excellent compared to the comparative example.

Claims (8)

A rubber composition for tire tread comprising raw rubber and a reinforcing filler,
The raw material rubber includes natural rubber and anionic polymerized butadiene rubber,
The anionic polymerized butadiene rubber has a vinyl content of 10 to 40% and is represented by the following formula (1),
The anionic polymerization butadiene rubber is an anionic polymerization butadiene rubber having a silica-affinity functional group prepared by obtaining a 1,3-butadiene polymer in a solution state through an anion activated using an alkyl lithium polymerization initiator and then reacting with a silica-affinity functional group. A rubber composition for a tire tread comprising:
[Formula 1]

In Formula 1,
R is any one selected from the group consisting of alkoxysilane-based, amine-based, carboxy-based, hydroxy-based and ester-based functional groups.
delete delete According to claim 1,
The rubber composition for tire tread, characterized in that the raw rubber comprises 60 to 90 parts by weight of the natural rubber and 10 to 40 parts by weight of the anionic polymerized butadiene rubber having the silica-affinity functional group.
According to claim 1,
The reinforcing filler includes at least one selected from the group consisting of carbon black and silica,
The reinforcing filler is a rubber composition for tire tread, characterized in that it is included in 10 to 70 parts by weight based on 100 parts by weight of the raw rubber.
According to claim 1,
The reinforcing filler includes carbon black and silica,
The carbon black is included in 1 to 9 parts by weight based on 100 parts by weight of the raw rubber,
The rubber composition for tire tread, characterized in that the silica is included in 1 to 69 parts by weight based on 100 parts by weight of the raw rubber.
A tire comprising the rubber composition for tire tread according to any one of claims 1 or 4 to 6.
According to claim 7,
The tire is characterized in that the tire is a truck tire or a bus tire.