KR100635608B1 - Tire tread rubber composition for improving good extrusion - Google Patents

Abstract

Provided are a tire tread rubber composition which is enhanced in extrusion, durability and heat generation characteristics, is reduced in viscosity and is improved in processability, and a tire containing the tread comprising the composition. The composition comprises 1-5 parts by weight of zinc 2-ethyl hexanoate as the dispersion aid of a reinforcing agent based on 100 parts by weight of a rubber material. Preferably the rubber material is selected from a natural rubber, a synthetic rubber or a mixture of a natural rubber and a synthetic rubber in a ratio of 1:9 to 9:1. Optionally the composition comprises further carbon black, or a mixture of carbon black and silica as a reinforcing agent.

Description

Tire tread rubber composition for improving good extrusion

The present invention relates to a tire tread rubber composition with improved extrudability. More specifically, in a conventional tire tread rubber composition, a tire using zinc-2-ethyl-hexanoate (ZEH) is used. It relates to a tire tread rubber composition that can lower the viscosity of the tread rubber composition to prevent scorch due to heat generation during the extrusion process of the rubber composition and improve productivity.

In general, tire treads are made of natural rubber and synthetic rubber as the main raw materials to improve the physical properties and other properties of the rubber materials of the main raw materials, and reinforcement, anti-aging agents, softeners, vulcanizing agents, and vulcanization accelerators are selected appropriately and used in an appropriate amount. To have.

In the tire, the tread is an area in direct contact with the ground as the vehicle moves, and the abrasion resistance should be excellent because the tread portion is gradually worn out by friction between the tire and the ground and the heat generated by the friction. All. In addition, since the vehicle rotates in a curve as well as straight, the rolling resistance of the tire should be good as the vehicle rotates. In addition, since the road surface gets wet due to rain or the road surface is often wetted by freezing or ice generated during the winter, the wet traction of the tire on the wet road surface should be excellent.

Conventional tire tread rubber composition mainly uses carbon black as a reinforcing material, and a large amount of carbon black is used to increase the tensile property and wear resistance of the rubber. However, when a large amount of carbon black is used as the reinforcing material, the viscosity of the rubber composition is increased, which causes various problems in the rubber extrusion process. In particular, a rubber composition having a high viscosity has a problem in that heat generation is deepened due to friction between rubber and a screw or a mold and a scorch when passing through an extruder, and the shape of the extrudate is changed.

The present invention devised to solve the problems mentioned above, in the tire tread rubber composition, by adding a dispersing aid that can improve the dispersibility of the reinforcing material to reduce the viscosity by extruding the rubber composition to reduce the viscosity of the rubber composition It is an object of the present invention to provide a tire tread rubber composition that can prevent scorch due to heat generation during the extrusion process and improve productivity.

Another object of the present invention is to provide a tire containing a tread made of the above rubber composition.

The tire tread rubber composition of the present invention for achieving the above-mentioned object is zinc-2-ethyl-hexanoate (Zinc-2-ethyl) as a dispersing aid with respect to 100 parts by weight of the raw rubber in the conventional tire tread rubber composition -hexanoate) may comprise 1 to 5 parts by weight.

In the present invention, the raw material rubber can be used as long as it can be used as the raw material rubber of the conventional tire tread rubber composition. Examples of such raw rubbers in the present invention include synthetic rubbers such as natural rubber, solution-polymerized styrene butadiene rubber, emulsion polymerization styrene butadiene rubber, butadiene rubber, styrene butadiene rubber containing isoprene, styrene butadiene rubber containing nitrile, and neoprene rubber. Each may be used alone or a mixture of two synthetic rubbers in a ratio of 1: 9 to 9: 1, or a mixture of three or more synthetic rubbers may be used. In addition, it is possible to use a mixture of the natural rubber and synthetic rubber mixed in a ratio of 1: 9 to 9: 1.

The tire tread rubber composition of the present invention may use carbon black alone or carbon black and silica as a reinforcing material.

When carbon black is used alone as a reinforcing material in the present invention, carbon black may be used in an amount of 40 to 65 parts by weight based on 100 parts by weight of the raw material rubber, wherein the carbon black has a BET value of 120 to 160 m ² indicating a surface area. / g, and the DBP adsorption amount which shows a structure can be used that is 110-160 ml / 100g.

When silica is used as the reinforcing material in the present invention as carbon black, silica may be used in an amount of 5 to 25 parts by weight based on 100 parts by weight of the raw material rubber, wherein silica has a BET value representing a surface area of 150 to ²⁰⁰ m ² /. g, and the DBP adsorption amount which shows a structure can be used that is 240-300 ml / 100g.

When using a mixture of carbon black and silica as a reinforcing material in the present invention, the carbon black having the above-mentioned characteristics may be used in an amount of 40 to 65 parts by weight based on 100 parts by weight of the raw material rubber, and the silica is 100 parts by weight of the raw material rubber. It can be used 5 to 25 parts by weight.

Dispersion aids, which are essential components of the present invention, may be used in an amount of 1 to 5 parts by weight of zinc-2-ethyl-hexanoate (ZEH) based on 100 parts by weight of the raw material rubber. In this case, zinc-2-ethyl-hexanoate has a zinc content of 6-10%, a silica content of 30-35%, more preferably a zinc content of 8%, and a silica content of 33% zinc-2-ethyl-hexanoate. Noate can be used.

In the present invention, when zinc-2-ethyl-hexanoate, a dispersion aid, is used in an amount of less than 1 part by weight based on 100 parts by weight of the raw material rubber, the viscosity decrease of the tire tread rubber composition is insignificant. Use of more than 5 parts by weight of 2-ethyl-hexanoate does not cause a marked increase in the effect of reducing the viscosity of the rubber composition. Therefore, in the present invention, zinc-2-ethyl-hexanoate may be used in an amount of 1 to 5 parts by weight based on 100 parts by weight of the raw material rubber.

Meanwhile, zinc-2-ethyl-hexanoate (ZEH) used as a dispersing aid in the present invention may be a commercially available one.

On the other hand, the present invention is applied to the tire tread rubber composition for a variety of properties, contents for the above-mentioned raw rubber, reinforcing materials, dispersion aids, the raw materials of the above-mentioned properties, content to achieve the object of the present invention It is recommended to use rubber, reinforcing materials, and dispersing agents.

According to the present invention, various additives such as activators, softeners, anti-aging agents, process oils, vulcanizing agents, and vulcanization accelerators, which are used in conventional tire tread rubber compositions, in addition to the above-mentioned raw rubbers and reinforcing materials, may be appropriately selected as necessary. Can be used. However, these are general components used in conventional tire tread rubber compositions and are not essential components of the present invention.

On the other hand, the present invention includes a tire having a tread made of the tire tread rubber composition. In this case, the tire is any one selected from among motorcycle tires, airplane tires, automobile tires, truck tires, and bus tires, and more preferably includes truck tires and bus tires.

Hereinafter, the present invention will be described by the following comparative examples, examples and test examples. However, these are not limited to the scope of the present invention by these as an embodiment of the present invention.

Comparative Example

57 parts by weight of carbon black, 5 parts by weight of silica, 1.5 parts by weight of silane coupling agent (SI-69), and process oil (Aromatic-) based on 100 parts by weight of raw rubber comprising 60 parts by weight of natural rubber (NR) and 40 parts by weight of butadiene rubber. 2) 6 parts by weight, stearic acid (1.5% by weight stearic acid), 3 parts by weight of zinc oxide (ZnO), 6 parts by weight of the antioxidant (RD) was put in a Banbury mixer and blended for 30 minutes at 150 ℃ and released.

Then, 2.2 parts by weight of sulfur as a vulcanizing agent and 0.9 parts by weight of N-cyclohexyl-2-benzothiazolsulfenamide (CZ) as a vulcanization accelerator were added to the above formulation and 20 minutes at 160 ° C. Was vulcanized to produce a rubber.

In the carbon black, a BET value of 120 to 160 m ² / g and a DBP adsorption amount of 110 to 160 ml / 100 g were used. Silica had a BET value of 150 to ²⁰⁰ m ² / g and a DBP adsorption amount of 240 to 300 ml / 100 g. Was used.

Table 1 below shows the components of the rubber of the comparative example.

<Example>

57 parts by weight of carbon black, 5 parts by weight of silica, 1.5 parts by weight of silane coupling agent (SI-69), zinc-2-ethyl based on 100 parts by weight of the raw material rubber consisting of 60 parts by weight of natural rubber (NR) and 40 parts by weight of butadiene rubber 3 parts by weight of hexanoate (ZEH), 6 parts by weight of process oil (Aromatic-2), 1.5 parts by weight of stearic acid, 3 parts by weight of zinc oxide, and 6 parts by weight of antioxidant (RD) in a Banbury mixer at 150 ° C. Release for 30 minutes after compounding.

Then, 2.2 parts by weight of sulfur as a vulcanizing agent and 0.9 parts by weight of N-cyclohexyl-2-benzothiazolsulfenamide (CZ) as a vulcanization accelerator were added to the above formulation and 20 minutes at 160 ° C. Was vulcanized to produce a rubber.

In the carbon black, a BET value of 120 to 160 m ² / g and a DBP adsorption amount of 110 to 160 ml / 100 g were used. Silica had a BET value of 150 to ²⁰⁰ m ² / g and a DBP adsorption amount of 240 to 300 ml / 100 g. Was used. In addition, zinc-2-ethyl-hexanoate (ZEH) used as a dispersing aid was used having a zinc content of 8% and a silica content of 33%.

Table 1 below shows the components of the rubber example.

Table 1. Compositions of Examples and Comparative Examples Rubber

Item Comparative example Example Natural rubber 60 60 Butadiene rubber 40 40 Carbon black 57 57 Silica 5 5 Silane coupling agent 1.5 1.5 ZEH - 3 Process oil 6 6 Stearic acid 1.5 1.5 Zinc oxide 3 3 Antioxidant (RD) (1) 6 6 Vulcanizing (sulfur) 2.2 2.2 Vulcanization accelerator (CZ) 0.9 0.9

(1) RD: 2,2,4-trimethyl-1,2-dihydroquinoline

<Test Example 1>

Physical properties such as tensile properties (hardness, 300% modulus, tensile strength, elongation), scorch time, viscosity, and heat generation were measured according to ASTM-related regulations for the rubbers of Examples and Comparative Examples, and the results are shown in Table 2 below. It was.

Table 2. Physical Properties of Examples and Comparative Examples Rubber

Item Comparative example Example Shore A 67/72 67/71 300% modulus (kg / cm ² ) 130/170 133/167 Tensile Strength (kg / cm ² ) 230/207 227/205 Elongation (%) 492/366 461/356 Scorch time (minutes) 32.1 36.2 Viscosity (100 ° C) 66 59 Fever (℃) 30.3 27.8

* Tensile property is the initial value / aging, aging conditions were left at 100 ℃ for 24 hours.

* 300% modulus of tensile aging, tensile strength is better the lower the rate of increase compared to the initial physical properties.

* The exothermic performance is excellent at the lower temperature, that is, the lower the value, and the better the viscosity (100 ℃).

* Longer scorch time favors fairness.

<Test Example 2>

The rubber extrudate surface temperature and the rubber extrudate internal temperature of the rubber prepared in Examples and Comparative Examples were measured and the results are shown in Table 3 below.

In addition, the rubber prepared in Examples and Comparative Examples was applied to a real vehicle of the 315 / 80R22.5 standard as a tread, and the durability (break time of the tread) and the actual vehicle wear index were measured and the results are shown in Table 3 below. It was.

Table 3. Properties of Examples and Comparative Examples Rubber

Item Comparative example Example Rubber Extruded Surface Temperature (℃) 139.0 132.0 Rubber Extruded Internal Temperature (℃) 146.0 139.0 Durability (break time) 64 hours 09 minutes 65 hours 50 minutes Actual vehicle wear index 100 103

* Durability is a measure of the time that a tread breaks by ECER-54, the speed endurance test of the European standard. The higher the value (break time), the better.

* Actual vehicle wear index of Examples is measured value converted to the measured value of the comparative example to 100 means that the higher the value is better.

Rubber of the present invention to which the dispersing aid is applied as in the result of Test Example 1, compared with the rubber of the comparative example without the dispersing aid, has a physical property equivalent or more, in particular, the exothermic property is excellent, the viscosity is reduced It can be seen that the fairness is improved.

In addition, as in the result of Test Example 2, the rubber of the example to which the dispersion aid was added, compared with the rubber of the comparative example without the dispersion aid stabilized scorch time is improved durability, and it can be seen that the wear characteristics are equal to or more than.

As described above, although described with reference to the preferred embodiment of the present invention, those skilled in the art will be variously modified without departing from the spirit and scope of the invention described in the claims below. And can be changed.

Claims (3)

In the tire tread rubber composition, A tire tread rubber composition comprising 1 to 5 parts by weight of zinc-2-ethyl-hexanoate based on 100 parts by weight of raw rubber. The tire tread rubber composition according to claim 1, wherein zinc-2-ethyl-hexanoate has a zinc content of 6 to 10% and a silica content of 30 to 35%. A tire comprising a tread made of the rubber composition of claim 1.