KR20060134483A - Tire tread composition - Google Patents

Abstract

Provided are a rubber composition for a tire tread which is improved in heat resistance and abrasion resistance, and a tire containing the tread made of the rubber comprising the composition. The rubber composition comprises 2-5 parts by weight of a surface-treated aramid monofilament based on 100 parts by weight of a rubber material. Preferably the aramid monofilament is coated with resorcinol formaldehyde. The surface-treated aramid monofilament has a Young's modulus of 20-30 MPa, a tensile strength of 2,400-3,000 MPa, an elongation at break of 3-4 %, and an aspect ratio of 50-300. Preferably the aramid monofilament is poly(p-phenylene terephthalamide) (PPPTA).

Description

Tire tread composition

The present invention relates to a tire tread rubber composition, and more particularly, to include aramid short fibers coated with a surface of resorcinol formaldehyde in a tire tread rubber composition, thereby improving tire and tread rubber properties. It relates to a composition.

As industrialization is highly advanced, vehicle manufacturing technology has been advanced and paved roads have increased, so that high-speed driving of vehicles has increased. This trend is not only for passenger cars, but also for trucks and buses, which are continuously increasing in high speed. Accordingly, in the tire industry, much research is being conducted on the development of high speed tires.

Tire tread is made of natural rubber or natural rubber and synthetic rubber as main raw materials, and reinforcing materials, anti-aging agents, softeners, vulcanizing agents and vulcanization accelerators are appropriately selected in order to improve physical properties and other properties of raw rubber.

In the tire, the tread is a part of the vehicle which is in direct contact with the ground as the vehicle moves, and thus the tread portion is gradually worn out due to the friction between the tire and the ground and the heat generated by the friction, thereby improving abrasion resistance and heat resistance characteristics. Must be excellent That is, the heat resistance and wear characteristics of the tire tread are determined by the nature of the tread surface in contact with the ground. In particular, heat generation, which is inevitably generated at high speeds, causes tire physical properties and wear resistance to deteriorate.

In addition to the wear resistance and heat resistance, the vehicle rotates in a curve as well as straight, so the rolling resistance of the tire should be good according to the rotation of the vehicle. 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.

In general, the natural rubber compound that is most commonly used as a tread rubber for truck tires and bus tires has a deterioration in wear characteristics due to heat generated during high-speed driving due to unsaturated bonds and double bonds in natural rubber and uneven wear. There is a problem that causes. In addition, when the truck or bus is driving on the unpaved road rather than the pavement, the tire tearing or wear-out rate increases more than the pavement road, which significantly reduces the life of the tire.

In order to solve this problem, an anti-aging agent having excellent heat resistance property or a rubber having excellent heat resistance property is used in combination with the raw material rubber, and the vulcanizing agent used for crosslinking is a single sulfur rather than a poly sulfide bond. (mono sulfide) has been tried to improve the stability to heat.

However, even in this case, the rubber properties such as wear characteristics and tearing of the tires are reduced, thereby limiting the application.

The present invention devised to solve the above-mentioned problem is to apply various components to the tire tread rubber composition, by applying the aramid short fibers coated with the surface of the resorcinol formaldehyde can improve the heat resistance and wear characteristics It has been found that a tire tread rubber composition can be obtained.

Accordingly, an object of the present invention is to provide a tire tread rubber composition containing aramid short fibers coated with a surface of resorcinol formaldehyde in a conventional tire tread rubber composition.

Another object of the present invention is to provide a tire having a tread as a rubber comprising a rubber composition containing short aramid fibers coated on the surface of resorcinol formaldehyde.

The tire tread rubber composition of the present invention for achieving the above-mentioned object includes 2 to 5 parts by weight of aramid short fibers surface-treated with respect to 100 parts by weight of the raw rubber in the conventional tire tread rubber composition.

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. In the present invention, as an example of such raw rubber, natural rubber alone, or synthetic rubber such as styrene butadiene rubber, butadiene rubber, isoprene rubber, styrene butadiene rubber containing isoprene, styrene butadiene rubber containing nitrile, and neoprene rubber alone Can be used as In addition, it is possible to use a mixed rubber mixed with the natural rubber and two or more synthetic rubber or a mixed rubber mixed with two or more synthetic rubber. As an example, a mixed rubber in which the natural rubber and the synthetic rubber are mixed in a ratio of 1: 9 to 9: 1 may be used. In the case of a mixed rubber in which two or more synthetic rubbers are mixed, a mixed rubber mixed in a ratio of 1: 9 to 9: 1 may be used, respectively.

The tire tread rubber composition of the present invention may include 2 to 5 parts by weight of aramid short fibers surface-treated with respect to 100 parts by weight of the raw rubber in the conventional tire tread rubber composition.

If less than 2 parts by weight of the aramid short fibers surface-treated in the present invention based on 100 parts by weight of the raw material rubber, the heat resistance and wear resistance of the rubber composition is reduced, the surface-treated aramid short fibers to 100 parts by weight of the raw rubber If it exceeds 5 parts by weight, the effect of increasing the aramid short fiber content of the rubber composition does not increase the obvious effect on the heat resistance and wear resistance properties. Therefore, the aramid short fibers surface-treated in the present invention is preferably contained 2 to 5 parts by weight based on 100 parts by weight of the raw material rubber.

As the aramid short fibers surface-treated in the present invention can be used that is coated with resorcinol formaldehyde on the fiber surface of the aramid short fibers. Polyparaphenylene terephthalamide (poly (paraphenylene terephthalamide), PPPTA) can be used as an example of the surface-treated aramid short fibers in the present invention. At this time, the physical properties of polyparaphenylene terephthalaramid are Young's Modulus 20-30MPa, Tensile Strength 2400-3000Mpa, Elongation at break 3-4%, Aspect ratio 50-300 Can be used.

As the aramid short fibers surface-treated in the present invention can be used as a commercially available product (Toray DuPont, Japan), and can also be used a coating of resorcinol formaldehyde on the surface of the aramid short fibers.

Meanwhile, in the tire tread rubber composition of the present invention, the surface-treated aramid short fibers of various properties and contents are applied. In order to achieve the object of the present invention, the surface-treated aramid short fibers are used in the above-mentioned properties and contents. It is good.

The present invention can be used in a predetermined amount by appropriately selecting various additives such as reinforcing agents, activators, 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. have. However, these are general components used in conventional tire tread rubber compositions, and thus are not essential components of the present invention, and thus the detailed descriptions thereof will be omitted.

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 may include any one selected from motorcycle tires, aircraft tires, automobile tires, truck tires, and bus tires, and more preferably may include truck tires or tires for buses.

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

As shown in Table 1 below, natural rubber is used as a raw material rubber. For 100 phr of the raw material rubber, carbon black (N103) 50 phr, zinc oxide (ZnO) 4 phr, stearic acid (2) stearic acid (A # 2 oil) 8 phr , 5phr of an anti-aging agent (2,2,4-trimethyl-1,2-dihydroquinoline, RD) was placed in a Banbury mixer, mixed at 150 ° C. for 30 minutes, and then released.

Then 2.0 phr of sulfur as a vulcanizing agent and 2.0 phr of N-cyclohexyl-2-benzothiazolsulfenamide (CZ) as a vulcanization accelerator were added to the above formulation for 30 minutes at 160 ° C. It was vulcanized to produce rubber.

<Example 1>

As shown in Table 1 below, natural rubber is used as a raw material rubber. For 100 phr of the raw material rubber, carbon black (N103) 50 phr, zinc oxide (ZnO) 4 phr, stearic acid (2) stearic acid (A # 2 oil) 8 phr , 5 phr of anti-aging agent (RD) and 3 phr of polyparaphenylene terephthalaramid (PPPTA) coated on the surface of resorcinol formaldehyde were placed in a Banbury mixer, blended at 150 ° C. for 30 minutes, and then released.

Then, 2.0 phr of sulfur as a vulcanizing agent and 2.0 phr of N-cyclohexyl-2-benzothiazolesulfenamide (CZ) as a vulcanization accelerator were added to the above formulation and vulcanized at 160 ° C. for 30 minutes to prepare a rubber.

The polyparaphenylene terephthal aramid (PPPTA) has a flat ratio of 50, Young's Modulus 20 to 30 MPa, Tensile strength 2400 to 3000 Mpa, Elongation at break 3 to 4%, Flat ratio (Aspect) ratio) 50-300 was used.

Table 1. COMPARATIVE EXAMPLES AND EXAMPLES Rubber Components (Unit: phr)

Item Comparative example Example 1 Example 2 Example 3 Example 4 Raw material rubber 100 100 100 100 100 Carbon black 50 50 50 50 50 Zinc oxide 4 4 4 4 4 Stearic acid 2 2 2 2 2 Process oil 8 8 8 8 8 Anti-aging 5 5 5 5 5 PPPTA - 3 5 3 5 Vulcanizing (sulfur) 2.0 2.0 2.0 2.0 2.0 Vulcanization accelerator (CZ) 2.0 2.0 2.0 2.0 2.0

<Example 2>

A rubber was manufactured in the same manner as in Example 1, except that 5 phr of polyparaphenylene terephthalaramid (PPPTA) was used.

<Example 3>

A rubber was manufactured in the same manner as in Example 1, except that 3 phr of polyparaphenylene terephthalaramid (PPPTA) having an aspect ratio of 300 was used.

<Example 4>

A rubber was manufactured in the same manner as in Example 1, except that 5 phr of polyparaphenylene terephthalaramid (PPPTA) having a flat ratio of 300 was used.

<Test Example 1>

Tensile Properties (Hardness, 100% Modulus, 300% Modulus, Tensile Strength, Elongation), Heat Built Up (HBU) Wear Characteristics (DIN Wear, PICO) Abrasion), cut and chip (Cut / Chip), Mooney viscosity was measured and the results are shown in Table 2 below.

Table 2. Physical Properties of Comparative Examples and Examples

Item Comparative example Example 1 Example 2 Example 3 Example 4 Tensile Properties Hardness 67 73 76 74 78 100% modulus 30 35.8 42.4 41.6 52 300% modulus 147.3 154.6 154.6 155.1 162 The tensile strength 290.2 265 245.8 256.5 243.3 Elongation 502.7 459.2 432.5 446.7 420.4 Fever (X-50) (℃) 27.2 23 24.8 23.1 24.9 Set (%) 97.3 96.9 95 95.7 94.2 DIN Abrasion Amount (g) 0.125 0.118 0.119 0.119 0.111 PICO Abrasion Amount (g) 0.0355 0.0310 0.0320 0.0300 0.0295 DIN Abrasion Amount (g) 0.125 0.100 0.100 0.098 0.091 Cut / Chip Loss (g) 2.9 2.45 2.35 2.15 2.15 Mooney Viscosity 73.65 74.06 74.21 76.52 78.44 T05 19.6 23.6 23.33 22.67 22.13

<Test Example 2>

Rubber prepared in Comparative Examples and Examples was applied as a tread of a truck / bus tire (11R22.5 956 pattern), and abrasion test and tearing occurrence rate were measured, and the results are shown in Table 3 below.

Table 3. Result of Tire Tread Application of Rubber

Item Comparative example Example 1 Example 2 Example 3 Example 4 Wear test 100 104 128 130 128 Tearing rate (%) 60 50 45 30 35

As shown in the results of the test example, the rubber of the embodiment to which the surface-treated aramid short fibers are applied is superior to the rubber of the comparative example without the surface-treated aramid short fibers, it can be seen that the wear resistance is also improved.

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

Claims (4)

In the tire tread rubber composition, A tire tread rubber composition comprising 2 to 5 parts by weight of aramid short fibers surface-treated with respect to 100 parts by weight of raw rubber. The tire tread rubber composition according to claim 1, wherein the short aramid fiber is coated with resorcinol formaldehyde on the surface of the fiber. The physical properties of the surface-treated aramid short fibers, Young's Modulus 20 ~ 30MPa, Tensile Strength 2400 ~ 3000Mpa, Elongation at break 3 ~ 4%, Flat ratio (Aspect ratio) Tire tread rubber composition, characterized in that 50 ~ 300. A tire comprising a rubber comprising a rubber composition of any one of claims 1 to 3 as a tread.