KR100693449B1 - Tire tread rubber composition for truck and bus - Google Patents

Abstract

The present invention relates to a tire tread rubber composition for trucks and buses, and more particularly, a rubber made of natural rubber and butadiene rubber having a cis content of 98% or more as a raw material rubber, and the raw material rubber to include aramid short fibers. A tire tread rubber composition for trucks and buses that can improve wear resistance.

The present invention relates to a tire tread rubber composition for trucks and buses, wherein butadiene rubber having a cis content of 98% or more is included in the raw material rubber, and the surface is made of resorcinol formaldehyde (RFL) as a filler for improving abrasion resistance and heat resistance. It is an object of the present invention to provide a tire tread rubber composition for trucks and buses that can improve abrasion resistance by using short aramid coated fiber.

In another aspect, the present invention is to provide a tire for trucks and buses including a rubber made of the rubber composition as a tread.

The tire tread rubber composition for trucks and buses of the present invention is a tire tread rubber composition for trucks and buses, which is made of natural rubber and rubber made of butadiene rubber having a cis content of 98% or more, and the raw material rubber is 100 parts by weight. About 0.5 to 5 parts by weight of aramid short fibers may be included.

Description

Tire tread rubber composition for truck and bus

The present invention relates to a tire tread rubber composition for trucks and buses, and more particularly, a rubber made of natural rubber and butadiene rubber having a cis content of 98% or more as a raw material rubber, and the raw material rubber to include aramid short fibers. A tire tread rubber composition for trucks and buses that can improve wear resistance.

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, so the abrasion resistance and the heat resistance should be excellent. .

The heat and wear resistance of tire treads is determined by the nature of the tread surface in contact with the ground. In particular, heat generation inevitably generated at high speeds causes a decrease in physical properties of the tire and a decrease in wear resistance.

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 is applied or a rubber having high heat resistance is mixed and used in raw material rubber, and the vulcanizing agent used for crosslinking is used as a mono sulfur rather than a poly sulfide bond. sulfide) has been attempted to improve thermal stability.

However, even in this case, the rubber properties such as wear characteristics and tearing of the tire are reduced, indicating a limit to the application.

In order to solve the above-mentioned problems, it has been found that the combination of the structural properties of butadiene rubber and the different types of fillers has different properties. Particularly, butadiene rubber having a cis content of 98% or more is included in raw rubber, and aramid short fibers coated with resorcinol formaldehyde (RFL) as a filler to improve abrasion resistance and heat resistance are improved. It was found that a rubber composition can be obtained.

 Therefore, in the tire tread rubber composition for trucks and buses, butadiene rubber having a cis content of 98% or more is included in the raw material rubber, and as resorcinol formaldehyde (RFL) as a filler for improving abrasion resistance and heat resistance. It is an object of the present invention to provide a tire tread rubber composition for trucks and buses which can improve abrasion resistance by using aramid short fibers coated on the surface.

In another aspect, the present invention is to provide a tire for trucks and buses including a rubber made of the rubber composition as a tread.

The tire tread rubber composition for trucks and buses of the present invention for achieving the above-mentioned object is a rubber tread rubber composition for a conventional truck and bus tire tread rubber composition, made of natural rubber and rubber made of butadiene rubber having a cis content of 98% or more. It may contain 0.5 to 5 parts by weight of aramid short fibers with respect to 100 parts by weight of the raw material rubber.

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 for trucks and buses.

In the present invention, as a raw material rubber of the tire tread rubber composition for trucks and buses, natural rubber and synthetic rubber may be used alone, or mixed rubbers in which natural rubber and synthetic rubber are mixed in a ratio of 1: 9 to 9: 1 may be used. Alternatively, a mixed rubber of two or more synthetic rubbers may be used.

The synthetic rubber may be any one or more selected from styrene butadiene rubber (SBR), butadiene rubber (BR), isoprene rubber (IR), chloroprene rubber (CR), nitrile rubber (NBR), and butyl rubber.

As an example of the raw material rubber, the present invention can use a mixed rubber composed of 50 to 80 parts by weight of natural rubber and 50 to 80 parts by weight of butadiene rubber with a Cis content of 98% or more.

In the present invention, butadiene rubber having a cis content of 98% or more can be obtained by using a neodymium catalyst instead of a nickel catalyst generally used as a catalyst for preparing butadiene rubber. have.

In order to improve wear resistance and heat resistance in the tire tread rubber composition for trucks and buses of the present invention, 0.5 to 5 parts by weight of aramid short fibers may be used as 100 parts by weight of raw rubber.

In the tire tread rubber composition for trucks and buses of the present invention, when the aramid short fibers are used in an amount of less than 0.5 parts by weight based on 100 parts by weight of the raw rubber, heat resistance and abrasion resistance are reduced. When used in excess of 5 parts by weight, there is a concern that the physical properties of the rubber may be deteriorated without the continuous improvement of the apparent effect on the heat resistance and the wear resistance.

Therefore, the tire tread rubber composition for trucks and buses of the present invention includes butadiene rubber having a cis content of 98% or more in the raw material rubber, and 0.5 to 5 parts by weight of short aramid fibers is used for 100 parts by weight of the raw material rubber. .

As long as the aramid short fibers used to improve heat resistance and wear resistance in the present invention can play such a role, any one can be used.

As an example of such short aramid fibers in the present invention has a structure of para-phenylene / 3,4-oxydiphenylene terepalamide (Young's Modulus) 20 ~ The surface of the aramid short fibers having a thickness of 22 GPa, a tensile strength of 3000 to 35000 MPa, an elongation of 5 to 10%, a diameter of 0.5 to 0.7 mm, and a length of 0.5 to 3.5 mm may be coated with a resorcinol formaldehyde solution.

In the tire tread rubber composition for trucks and buses of the present invention, the reinforcement may use carbon black.

In the present invention, the reinforcing material may be used as long as it can be used as a reinforcing material of the tire tread rubber composition for conventional trucks and buses.

As one example of the carbon black used as the reinforcing material in the present invention, one having iodine adsorption of 110 to 130 mg / g and DBP adsorption of 10 to 125 cc / mg can be used.

According to the present invention, various additives such as reinforcing agents, activators, softeners, process oils, vulcanizing agents, and vulcanization accelerators, which are used in conventional tire tread rubber compositions in addition to the above-mentioned raw rubber and short aramid fibers, are appropriately selected as necessary. It can be used in a predetermined content. However, these are general components used in tire tread rubber compositions for trucks and buses, and thus are not essential components of the present invention.

Meanwhile, another object of the present invention is to provide a tire including a rubber made of the tire tread rubber composition for trucks and buses as a tread.

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

50 parts by weight of carbon black and zinc oxide (ZnO) against 80 parts by weight of raw rubber consisting of 80 parts by weight of natural rubber and 20 parts by weight of butadiene rubber (Ni-BR) having a cis content of 95% using a nickel catalyst. ) 3 parts by weight, process oil (Aromatic-2) 2 parts by weight, stearic acid (3 parts by weight), anti-aging agent (N- (1,3-Dimethylbutyl)-N'-phenyl-p-phenylene diamine, Kumanox- 13) 1 part by weight was placed in a Banbury mixer, blended at 150 ° C. for 30 minutes, and then discharged.

Then, 2 parts by weight of sulfur as a vulcanizing agent and 1.0 part by weight of N-butylbenzothiazole sulfenamide (NS) as a vulcanization accelerator were added to the above formulation, and vulcanized at 160 ° C. for 20 minutes to prepare a rubber. .

Carbon black was used as the iodine adsorption 110 ~ 130mg / g, DBP adsorption 10 ~ 125cc / mg.

<Example>

80 parts by weight of natural rubber and 50 parts by weight of carbon black and zinc oxide (ZnO) based on 100 parts by weight of raw material rubber consisting of 20 parts by weight of butadiene rubber (Nd-BR) having a cis content of 98% by using a niobium catalyst when manufacturing butadiene rubber. ) 3 parts by weight, 2 parts by weight of process oil (Aromatic-2), 3 parts by weight of stearic acid, 1 part by weight of anti-aging agent (Kumanox-13), 3 parts by weight of aramid short fibers in a Banbury mixer at 30 ℃ It was formulated for minutes and then released.

Then, 2 parts by weight of sulfur as a vulcanizing agent and 1.0 part by weight of N-butylbenzothiazole sulfenamide (NS) as a vulcanization accelerator were added to the above formulation and vulcanized at 160 ° C. for 20 minutes to prepare a rubber.

 Carbon black was used as the iodine adsorption 110 ~ 130mg / g, DBP adsorption 10 ~ 125cc / mg.

In addition, the short aramid fibers have a structure of para-phenylene / 3,4-oxydiphenylene terephalamide (Young's Modulus) 20 to 22 GPa, tensile strength The surface of the aramid short fibers of 3000 to 35000 MPa, 5 to 10% elongation, 0.5 to 0.7 mm in diameter, and 0.5 to 3.5 mm in length was coated with a resorcinol formaldehyde solution.

Table 1. Compositions of Examples and Comparative Examples Rubber (Unit: parts by weight)

Item Comparative example Example Natural rubber 80 80 Ni-BR 20 - Nd-BR - 20 Carbon black 50 50 Zinc oxide 3 3 Process oil 2 2 Stearic acid 3 3 Anti-aging One One Aramid Short Fiber - 3 Vulcanizing agent 2 2 Vulcanization accelerator One One

<Test Example>

Exothermic test, Tanδ (70 ° C.), Blow out, Hardness, 300% Modulus, Tensile Strength (kgf), Wear Characteristics (PICO) (g) The physical properties as described above and the results are shown in Table 2 below.

Table 2. Physical Properties of Examples and Comparative Examples Rubber

Item Comparative example Example Exothermic Test (Index) (1) 100 110 Tanδ (70 ° C) (2) 0.080 0.072 Blowout 45 60 Hardness 64 66 300% modulus 265 263 Tensile strength (kgf) 590 598 Wear Characteristics (PICO) (g) (3) 0.29 0.22

(1) The numerical value of the fever index indicates the numerical value of the example when the value of the comparative example is set to 100. The higher the numerical value, the better.

(2) Tan δ (70 ℃): It is a value that can predict rolling resistance characteristics of tire performance. The lower the value, the better.

(3) PICO wear characteristics indicate wear values using B.F goodrich Abrasion Test. The lower the value, the better the wear resistance.

As in the results of the test example, butadiene rubber having a cis content of 98% or more is included in the raw material rubber, and the rubber of the example including aramid short fibers includes butadiene rubber having a cis content of 95% in the raw material rubber, and includes aramid short fibers. It can be seen that heat resistance and abrasion resistance are superior to the rubber of the comparative example which does not.

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 invention described in the claims below. It will be appreciated that it can be changed.

Claims (4)

In the tire tread rubber composition for trucks and buses, A raw material rubber is made of natural rubber and butadiene rubber having a cis content of 98% or more, and para-phenylene / 3,4-oxydiphenylene terepalamide is used based on 100 parts by weight of the raw material rubber. , 4-dxyldiphenylene terephalamide) and the surface of the aramid short fibers of Young's Modulus 20 to 22 GPa, tensile strength 3000 to 35000 MPa, elongation 5 to 10%, diameter 0.5 to 0.7 mm, length 0.5 to 3.5 mm A tire tread rubber composition for trucks and buses, comprising 0.5 to 5 parts by weight of aramid short fibers coated with a resorcinol formaldehyde solution. The tire tread rubber composition for a truck and a bus according to claim 1, wherein the raw material rubber is made of 50 to 80 parts by weight of natural rubber and 50 to 80 parts by weight of butadiene rubber with a Cis content of 98% or more. delete Claims 1. Truck and bus tires comprising a rubber made of the first rubber composition as a tread.