KR100450639B1 - Rubber composition for tire tread using nanoclay as reinforcing agent - Google Patents

Abstract

The present invention relates to a rubber composition for a tire tread using nanoclay as a reinforcing agent, and more particularly, to finely split a general clay into a plate-like structure and to surface-treat it with a polymer, thereby increasing the spacing between the plates to reduce the interparticle bonding force. It relates to a rubber composition, characterized in that used as a reinforcing agent together with carbon black.

According to the present invention, by having a plate-like structure, a rubber composition using nanoclay having excellent reinforcement performance together with carbon black as a reinforcing agent is applied to a tread portion of a bus or truck tire, thereby improving chip cut resistance of the tread portion. In addition, it can be seen that wear resistance, low fuel consumption performance, rotational resistance performance and low heat generation performance are all improved.

In addition, since the nanoclay exhibits excellent physical properties even when only a small amount is used, the weight reduction effect of the rubber composition may be additionally obtained.

Description

Rubber composition for tire tread using nanoclay as reinforcing agent}

The present invention relates to a rubber composition for a tire tread using nanoclay as a reinforcing agent, and more particularly, to finely split a general clay into a plate-like structure and to surface-treat it with a polymer, thereby increasing the spacing between the plates to reduce the interparticle bonding force. By using the carbon black as a reinforcing agent with respect to the chip composition of the tread portion of the tires for buses, trucks, as well as a rubber composition with improved wear resistance, low fuel consumption performance, rolling resistance performance and low heat generation performance.

The chip-cut refers to an abnormal wear phenomenon in which the tread portion of the tire is cut or dropped at the end of wear, which seriously affects not only tire life but also regeneration.

In general, the product quality problem that appears directly to consumers in the domestic and overseas markets is such chip-cut performance and wear-resistance performance. Among them, chip cut occurs frequently in mountainous areas with severe use conditions or in gravel-rich dirt roads. In order to improve the chip cut resistance, a rubber composition may be manufactured using silica having specific properties as a reinforcing agent.

Meanwhile, with the development of the tire industry, technology for producing low fuel consumption, low rolling resistance and environmentally friendly products is expanding, and the first interest is to improve the interaction between carbon black and polymer, which is widely used as a reinforcing agent. I wanted to.

However, the high elasticity is maintained when the carbon black is excessively added.However, due to the characteristics of carbon black, the heat generation of the rubber increases the durability of the tire by reducing the durability of the tire. There is a problem of lowering.

As a solution to this, there was a case in which a certain amount of a specific resin was mixed and a crosslinked structure was adjusted to apply a low heat generation high elastic compound, but despite such efforts, heat generation or abrasion performance was not significantly reduced.

In addition, in the case of the tread rubber composition used in the conventional low fuel efficiency tire, it can be seen that it is very difficult to simultaneously improve the wear resistance with low fuel efficiency. That is, when the amount of carbon black is increased in order to solve the problem of low wear resistance, there is a problem that low fuel consumption performance is lowered. The chip cut performance is also known to be degraded when raising the fuel economy performance.

Looking at the prior art related to the reinforcing agent of the tire rubber composition, Korean Patent Publication No. 2000-74059 discloses a tread rubber composition using chitin as a reinforcing agent to improve grip performance and rolling resistance performance. In addition, Korean Patent Laid-Open Publication No. 1999-81388 discloses that a silica component contained in a general clay is surface treated with a silane coupling agent and then applied to a back tire tire rubber composition and a tread rubber composition.

In addition, the use of general clay in a white rubber composition for tires is disclosed in Korean Patent Laid-Open Publication No. 1999-80525, where reinforcement is deteriorated by using clay instead of carbon black as a reinforcing agent and the physical properties of white rubber are reduced. Add rhodium complex to solve this problem.

In addition, many patents using clay in white rubber compositions use common clay to improve color and crack resistance.

Therefore, in the present invention, not only to improve the chip cut resistance of the tread portion of the bus, truck tires, but also to improve the wear resistance, low fuel consumption performance, rolling resistance performance and low heat generation performance, instead of using a general clay as a reinforcing agent, reinforcement instead of An object of the present invention is to provide a tread rubber composition characterized by using a nanoclay having excellent performance together with carbon black.

1 is a view showing the structure of the nanoclay used in the present invention.

FIG. 2 shows the process by which nanoclays are dispersed on a rubber when compounded with the rubber.

In order to achieve the above object, the present invention provides a rubber composition for a tire tread, characterized in that the nanoclay and carbon black are used together as a reinforcing agent in the rubber composition comprising the raw material rubber and the reinforcing agent.

The rubber composition for tire treads of the present invention exhibits excellent physical properties including chip cut resistance, in particular, by being used in tread portions of tires for buses and trucks.

According to the composition, it contains 30 to 45 parts by weight of carbon black as a reinforcing agent and 5 to 20 parts by weight of nanoclay, and optionally 2 to 10 parts by weight of zinc oxide and 1 to 5 parts by weight of stearic acid, based on 100 parts by weight of the raw material rubber. 1 to 3 parts by weight of an aromatic oil as a softener, 1 to 3 parts by weight of an amine compound as an anti-aging agent, 1 to 5 parts by weight of sulfur as a vulcanizing agent, and 1 to 5 parts by weight of a sulfenamide compound or a thiuram compound as a vulcanization accelerator. It may further comprise one or more selected.

In the case of the carbon black, when the amount of less than 30 parts by weight is used, the reinforcement required by the tread is inferior, and if it exceeds 45 parts by weight, the heat generation increases and the durability decreases. In addition, when the amount of less than 5 parts by weight of nanoclay is used, the effect of improving chip cut performance is insignificant, and if it exceeds 20 parts by weight, the reinforcement performance is exceeded, thereby increasing heat generation and reducing wear performance.

In addition, it is preferable to use natural rubber or a mixture of natural rubber and butadiene rubber as the raw material rubber, and as an amine compound which is an anti-aging agent, m -tolenediamine, phenylnaphthylamine or diphenyl p -phenylenediamine, etc. It is preferable to use, and as the sulfenamide compound which is a vulcanization accelerator, N-cyclohexylbenzothiazole-2-sulfenamide, Nt-butylbenzothiazole-2-sulfenamide or N-oxydiethylbenzothiazole- 2-sulfamide, and the like, as the thiuram compound, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrabutylthiuram disulfide or tetrakis (2-ethylhexyl) thiuram disulfide It is preferable.

Nanoclay used as a reinforcing agent in the present invention, as shown in Figure 1, by dividing the general clay into a plate-like structure and then surface treatment with a polyolefin-based polymer to increase the inter-plate spacing to reduce the inter-particle binding force, as shown in Figure 2 As can be seen that when the nanoclay is compounded with the rubber, it is broken on the rubber to facilitate dispersion.

Such nanoclays may exhibit excellent reinforcing performance due to the plate-like structure.

In the structure of the nanoclay used in the present invention, the thickness of the individual platelets is about 1 nm, the aspect ratio is about 200 to 500, the width is about 100 to 1000 nanometers (nm), and the spacing between the plates is 10 to 50 microseconds.

Hereinafter, the present invention will be described in more detail based on Examples. However, this invention is not limited by the following Example.

Example 1. Preparation of rubber composition comprising nanoclay according to the present invention (1)

A mixture of natural rubber and butadiene rubber as raw materials, carbon black and nanoclay as reinforcing agents, zinc oxide and stearic acid as vulcanizing agents, aromatic oils as softeners, amine compounds as anti-aging agents, and vulcanizing agents as shown in Table 1 below. Sulfuramide compounds, sulfur and vulcanization accelerators, were mixed in a Banbury mixer and then released at a temperature of 160 ° C.

In detail step by step, first, the carbon black and the aromatic oil is added to two-thirds of the amount shown in Table 1 to 100 parts by weight of the raw rubber made of 80 parts by weight of natural rubber and 20 parts by weight of butadiene rubber, Nanomer I.44PA (New PP Nanomer grade), zinc oxide, stearic acid and diphenyl p -phenylenediamine, which are nanoclays surface-treated with polypropylene, were added in the amounts shown in Table 1 below and mixed in a Banbury mixer. After the release at a temperature of 160 ℃ to prepare a primary compounded rubber. Next, the remaining 1/3 of the remaining carbon black and aromatic oil were added to the primary compounded rubber, mixed in a Banbury mixer, and then discharged at 160 ° C. to prepare a secondary compounded rubber. Sulfur and N-cyclohexylbenzothiazole-2-sulfenamide were added thereto, mixed in a Banbury mixer, and then released after 1 minute and 30 seconds to prepare a rubber composition including the nanoclay according to the present invention.

Example 2. Preparation of rubber composition comprising nanoclay according to the present invention (2)

As shown in the mixing ratio as shown in Table 1 below, the total amount of carbon black as the reinforcing agent is 35 parts by weight, and 10 parts by weight of the nanoclay is used in the present invention in the same manner as in Example 1 above. To prepare a rubber composition comprising a nanoclay according to.

Example 3 Preparation of Rubber Composition Comprising Nanoclays According to the Present Invention (3)

As shown in the mixing ratio as shown in Table 1 below, the total amount of carbon black as the reinforcing agent is 30 parts by weight, and 15 parts by weight of the nanoclay is used in the present invention in the same manner as in Example 1 above. To prepare a rubber composition comprising a nanoclay according to.

Comparative Example 1. Preparation of rubber composition containing no nanoclay (1)

As shown in the mixing ratio as shown in Table 1 below, nanoclay is not used as a reinforcing agent, and nanoclay is not included in the same manner as in Example 1 except that the total amount of carbon black is 50 parts by weight. Rubber composition was prepared.

Comparative Example 2. Preparation of rubber composition containing no nanoclays (2)

As shown in the mixing ratio as shown in Table 1 below, the nanoclay is not used as a reinforcing agent, and the total amount of carbon black is 45 parts by weight, and the same as in Example 1 except that 8 parts by weight of silica is used. A rubber composition containing no nanoclay was prepared by the method.

TABLE 1

Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Raw material rubber 100 100 100 100 100 Carbon black 50 45 40 35 30 Silica - 8 - - - Nanoclay - - 5 10 15 Zinc oxide 3 3 3 3 3 Stearic acid 2 2 2 2 2 Vulcanizer 2 2 2 2 2 Vulcanization accelerator One One One One One Anti-aging 2 2 2 2 2

Experimental Example Physical property test for rubber products of Examples and Comparative Examples

In the experimental example, the physical properties of the rubber products obtained according to the above Examples and Comparative Examples were measured, and the results are shown in Table 2.

TABLE 2

division Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Hardness 66 67 67 68 68 Tensile Strength (㎏f / ㎠) 200 205 209 215 220 Elongation (%) 550 570 610 595 574 Breaking energy 100 105 115 112 105 Tanδ (60 ° C) 0.09 0.09 0.085 0.09 0.095 Wear (g) 100 99 110 105 105 Tear 100 104 110 108 100 Chip Cut Index 100 105 115 110 99

Looking at the simple test method for each test item and the meaning of the results, first, tanδ was measured using RDS (Rheo Dynamic Spectroscopy) viscoelasticity meter, tanδ at 60 ℃ represents the rotational resistance, The lower the value, the better the rotational resistance.

Abrasion degree refers to Lambbourn abrasion, which represents the loss of worn rubber by rotating at a skid ratio of 25% and a load of 1.5 kg using a rambon abrasion tester at room temperature. Indexed values indicate that the higher the value, the better the wear performance.

Tear is an index value of the value obtained by converting Comparative Example 1 to 100 after performing the Tear test, and the higher the value, the better the chip cut performance.

The chip cut index is a value obtained by using a chip-cut tester, a unique tester of Hankook Tire Co., Ltd., which measures the weight loss and indexes the resin when the Comparative Example 1 is converted to 100. Higher values indicate better chip cut performance.

From the results of Table 2, in the rubber composition containing the nanoclay according to the present invention prepared from Examples 1 to 3 it can be seen that the chip cut performance is improved and the wear performance, braking performance and rotational resistance performance are all equal or excellent. have. In addition, when the tan δ at 60 ° C. of Examples 1 to 3 is compared with the comparative example, an advantageous value is equal to or higher than that of the rubber composition according to the present invention. Able to know.

As described above, by applying a rubber composition using nanoclay having excellent reinforcement performance together with carbon black as a reinforcing agent to a tread portion of a bus or truck tire, the chip cut resistance of the tread portion is excellent as described above. In addition, it can be seen that wear resistance, low fuel consumption performance, rotational resistance performance and low heat generation performance are all improved.

In addition, since the nanoclay exhibits excellent physical properties even when only a small amount is used, the weight reduction effect of the rubber composition may be additionally obtained.

Claims (5)

30 to 45 parts by weight of carbon black as a reinforcing agent based on 100 parts by weight of the raw material rubber; 5 to 20 parts by weight of nanoclays surface-treated with a polyolefin-based polymer as a reinforcing agent; And optionally at least one additive selected from the group consisting of zinc oxide as a vulcanizing agent, stearic acid as a vulcanizing agent, a softener, an antioxidant, a vulcanizing agent and a vulcanization accelerator. The method of claim 1, The vulcanizing agent is 1 to 10 parts by weight based on 100 parts by weight of the raw material rubber, 1 to 3 parts by weight based on 100 parts by weight of the raw material rubber, anti-aging agent is 1 to 3 parts by weight based on 100 parts by weight of the raw material rubber, vulcanizing agent Is 1 to 5 parts by weight based on 100 parts by weight of the raw material rubber and the vulcanization accelerator comprises 1 to 5 parts by weight based on 100 parts by weight of the raw material rubber. The method of claim 1, The nanoclay is a rubber composition for a tire tread, characterized in that the finely divided clay into a plate-like structure and then surface treatment with a polyolefin-based polymer to increase the spacing between the plates to reduce the bonding strength between the particles. The method of claim 3, wherein The nanoclay has a tire plate thickness of 1 to 5 nm, an aspect ratio of 200 to 500, a width of 100 to 1000 nm, and a space between plate shapes of a rubber tread for tire treads. delete