KR20070002825A - Tire tread rubber composition for improving good extrusion - Google Patents

Abstract

Provided are a rubber composition for a tire tread which is lowered in viscosity, is prevented in the generation of scorch due to the heat generation during extrusion and is improved in productivity, and a tire containing the tread prepared from the composition. The rubber composition comprises 1-5 parts by weight of VP1440 (aromatic disulfide and fatty acid) based on 100 parts by weight of a rubber material. Preferably the VP1440 comprises an aromatic disulfide and a fatty acid in a ratio of 1:9 to 9:1. Preferably the rubber composition comprises further carbon black, or a mixture of carbon black and silica as a reinforcing agent; and the rubber material is a natural rubber, a synthetic rubber or their mixture.

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, VP1440 (Aromatic Disulphide & Fatty Acid) is used to lower the viscosity of the tire tread rubber composition to extrude the rubber composition. The present invention relates to a tire tread rubber composition which can prevent scorch due to heat generation and improve productivity by preventing a shape change of the extrudate.

In the tire, the tread is a portion of the tire which is in direct contact with the ground as the vehicle moves, and thus, the tread portion is gradually worn out by friction between the tire and the ground, and thus, the abrasion resistance should be excellent. In addition, since the vehicle rotates in a straight line as well as in a straight line, the road surface gets wet due to the rolling resistance performance of the tire and the rain due to the rotation of the vehicle, or the road surface gets wet due to freezing or ice generated during the winter season. Therefore, the wet traction of the tire on wet roads should be excellent.

Tire treads are made of natural rubber and synthetic rubber as the main raw materials to improve the physical properties and other properties of rubber materials. To improve the wear resistance, anti-aging agents, softeners, vulcanizing agents, and vulcanization accelerators, the appropriate amount is used. Doing.

Conventionally, tread rubber for tires, especially tread rubbers used for heavy load tire treads such as trucks and buses, mainly uses natural rubber to maintain heat resistance, and a large amount of carbon black is used to maintain abrasion resistance through a reinforcing effect. Doing.

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, the rubber composition having a high viscosity has a problem in that heat generation is deepened due to friction between rubber and screw or rubber and detention when passing through the extruder, and scorch occurs, and the shape of the extrudate is changed to decrease productivity.

The present invention devised to solve the above-mentioned problems, in the tire tread rubber composition, to solve the anxiety factor of the extrusion process due to the high viscosity, prevent scorch, and add various components to the rubber composition to improve productivity When applied to the raw material rubber content of VP1440 (Aromatic Disulphide & Fatty Acid) in a predetermined amount, the viscosity of the rubber composition is lowered, and as a result, it was found that the anxiety factor of the extrusion process was completed. .

Accordingly, an object of the present invention is to provide a tire tread rubber composition capable of reducing the viscosity by reducing the viscosity by including VP1440 (Aromatic Disulphide & Fatty Acid) in a conventional tire tread rubber composition.

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 may include 1 to 5 parts by weight of VP1440 (Aromatic Disulphide & Fatty Acid) based on 100 parts by weight of raw rubber in a conventional rubber 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. As an example of such raw rubber in the present invention, natural rubber or synthetic rubber may be used, or mixed rubber in which natural rubber and synthetic rubber are mixed in a ratio of 1: 9 to 9: 1 may be used. In addition, it is possible to use a mixed rubber in which two synthetic rubbers are mixed in a ratio of 1: 9 to 9: 1, or a mixed rubber in which three or more synthetic rubbers are mixed.

The synthetic rubber may be any one or more selected from solution polymerization styrene butadiene rubber, emulsion polymerization styrene butadiene rubber, butadiene rubber, styrene butadiene rubber containing isoprene, styrene butadiene rubber containing nitrile and neoprene rubber.

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

Carbon black used as a reinforcing material in the present invention can be used as long as it is used in conventional tire tread rubber composition. As an example of the carbon black in the present invention, the BET value representing the surface area is 120 to 160 m ² / g, and the DBP adsorption amount representing the structure is 110 to 160 ml / 100 g, based on 100 parts by weight of the raw material rubber. 40-65 weight part can be used.

In the present invention, silica used as a reinforcing material such as carbon blade may be used as long as it is used in a conventional tire tread rubber composition. As an example of the silica in the present invention, the BET value representing the surface area is 150 to ²⁰⁰ m ² / g, and the DBP adsorption amount representing the structure is 240 to 300 ml / 100 g, based on 100 parts by weight of the raw material rubber. -25 weight part can be used.

In the tire tread rubber composition of the present invention, the dispersion component, which is an essential component used to reduce the viscosity of the rubber composition, may use 1 to 5 parts by weight of VP1440 (Aromatic Disulphide & Fatty Acid) based on 100 parts by weight of the rubber material.

In the present invention, when less than 1 part by weight of VP1440 (Aromatic Disulphide & Fatty Acid) is used based on 100 parts by weight of raw rubber, the viscosity of tire tread rubber composition is insignificant, and VP1440 (Aromatic Disulphide & Fatty Acid) is used by more than 5 parts by weight. There is no apparent rise in effect on the viscosity reduction of the rubber composition. Therefore, in the present invention, VP1440 (Aromatic Disulphide & Fatty Acid) is preferably used in an amount of 1 to 5 parts by weight based on 100 parts by weight of the rubber material.

VP1440 (Aromatic Disulphide & Fatty Acid) containing as an essential component in the present invention can be used that consists of aromatic disulphide (Aromatic Disulphide) and fatty acid (Fatty Acid) in the ratio of 1: 9-9: 1. The fatty acid in VP1440 may be any one selected from fatty acids having 4 to 22 carbon atoms. For example, butyric acid, caproic acid, caprylic acid, capric acid, lauric acid, myristic acid, palmitic acid, stearic acid, arachic acid or behenic acid may be used.

In addition, VP1440 (Aromatic Disulphide & Fatty Acid) can be used as a commercially available product.

On the other hand, the present invention is applied to the tire tread rubber composition of the raw material rubber, reinforcing material of various properties, content with respect to the raw material rubber, the reinforcing material mentioned above, in order to achieve the object of the present invention, the raw material rubber, reinforcing material is mentioned above It is advisable to use materials with the characteristics of raw material rubber and reinforcement.

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, and a silane coupling agent (SI-69) based on 100 parts by weight of the raw material rubber including 60 parts by weight of natural rubber (NR) and 40 parts by weight of butadiene rubber (BR), as shown in Table 1 below. 1.5 parts by weight, process oil (Aromatic-2) 6 parts by weight, stearic acid (1.5% by weight), zinc oxide (ZnO) 3 parts by weight, anti-aging agent (2,2,4-trimethyl-1,2-dihydroquinoline, RD) 6 parts by weight was placed in a Banbury mixer, blended at 150 ° C. for 30 minutes and then 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 140 to 150 m ² / g and a DBP adsorption amount of 150 to 160 ml / 100 g were used. Silica had a BET value of 170 to 180 m ² / g and a DBP adsorption amount of 260 to 270 ml / 100 g. Was used.

<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), VP1440 3 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 (BR). Parts by weight, 6 parts by weight of process oil (Aromatic-2), 1.5 parts by weight of stearic acid, 3 parts by weight of zinc oxide (ZnO), and 6 parts by weight of antioxidant (RD) in a Banbury mixer for 30 minutes at 150 ° C. After compounding it was released.

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

In the carbon black, a BET value of 140 to 150 m ² / g and a DBP adsorption amount of 150 to 160 ml / 100 g were used. Silica had a BET value of 170 to 180 m ² / g and a DBP adsorption amount of 260 to 270 ml / 100 g. Was used.

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 VP1440 - 3 Process oil 6 6 Stearic acid 1.5 1.5 Zinc oxide 3 3 Antioxidant (RD) 6 6 Vulcanizing agent (sulfur) 2.2 2.2 Vulcanization accelerator (CZ) 0.9 0.9

<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.

* The 300% modulus and tensile strength of tensile property is better when the property rate after aging is lower than the initial property.

* 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 (℃) 139.0 131.0 Rubber Extruded Internal Temperature (℃) 146.0 138.0 Durability (break time) 64 hours 09 minutes 67 hours 10 minutes Actual vehicle wear index 100 104

* 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.

As in the result of Test Example 1, the rubber of the present invention to which VP1440 is applied has a physical property equivalent to or higher than that of the rubber of Comparative Example to which VP1440 is not applied. It can be seen that the improvement.

In addition, as in the result of Test Example 2, the rubber of the example to which the VP1440 was added, compared with the rubber of the Comparative Example without using the VP1440, the stabilization time is improved by stabilizing the scorch time, the wear characteristics can be seen that the equivalent level or more.

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 (3)

In the tire tread rubber composition, A tire tread rubber composition comprising 1 to 5 parts by weight of VP1440 (Aromatic Disulphide & Fatty Acid) based on 100 parts by weight of raw rubber. The tire tread rubber composition according to claim 1, wherein VP1440 is composed of aromatic disulfide and fatty acid in a ratio of 1: 9 to 9: 1. A tire comprising a tread made of the rubber composition of claim 1.