KR101939496B1 - Rubber composite of heavy tyre - Google Patents

Abstract

The present invention provides a rubber composite of a heavy tire. According to the present invention, the rubber composite of a heavy tire comprises: carbon black made of material rubber and a reinforcing material; and a sulfate-based process material reacting to a double bond of the material rubber, and capable of being amide-coupled to the carbon black. Therefore, coupling characteristics between a material rubber composite and the reinforcing material are improved to secure appropriate material properties advantageous for low fuel consumption tire performance, and at the same time, improve wear resistance performance.

Description

 [0001] The present invention relates to a rubber composition of heavy tire,

The present invention relates to a rubber composition for a heavy duty tire, and more particularly to a rubber composition for a heavy duty tire, which improves the bondability between a rubber composition for a heavy load and a reinforcing material to secure proper properties favorable to low- Tire rubber composition.

As the transportation technology of the vehicle develops, the distance by which the transportation vehicle is operated in a single direction is getting longer. Therefore, consumers want a fuel-efficient tire with low fuel consumption and long life, There is a problem of having a trade-off relationship.

Nonetheless, consumers are eager to purchase tires with improved wear and fuel economy, increased interest in environmental issues around the world, increased fuel-economy regulations and certification systems for heavy-duty tires Therefore, the development of technology for low fuel consumption performance of heavy duty tires is continuously becoming important.

In order to improve the abrasion resistance and the fuel consumption of the rubber composition at the same time, the conventional technique is to improve the carbon black used as the reinforcing material by applying the technique used in the tires for passenger cars or by applying silica, There have been many studies to apply rubber.

However, when the technology used in the tires for passenger cars is applied as it is, there are many cases where the performance of the rubber compound is not realized in the actual heavy duty tire because the load conditions and the air pressure applied to the tires are different. For example, [0004] In addition, although the techniques using the sulfenamide system have been disclosed in the publications of U.S. Patent Nos. 1013518 and 746337, there have been some cases in which the low fuel consumption performance and the wear resistance performance are lower than those of the conventional rubber compositions.

In order to solve the problems of the prior art as described above, synthetic rubbers usable for heavy duty tires have been developed. However, when such synthetic rubbers are applied, the process characteristics and compounding characteristics of the rubber compositions are lowered, The tread-off relationship of the rubber composition can not be overcome or the abrasion resistance and the fuel consumption performance are reduced.

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a rubber composition for a heavy-duty tire which improves the bondability between a tire rubber composition and a reinforcing material to ensure appropriate physical properties favorable to low- .

The present invention, in order to solve the above technical problems, is characterized by comprising a raw material rubber, a carbon black as a reinforcing material, and a sulfate-based process aid capable of reacting with a double bond of the raw rubber and forming an amide bond with carbon black A rubber composition for a heavy duty tire is provided.

According to an embodiment of the present invention, the carbon black may include a carboxyl group on its surface.

According to another embodiment of the present invention, the process aid may be H ₂ N- (CH ₂ ) _x -SO ₄ H (X: an integer greater than or equal to 8 and no greater than 20).

According to another embodiment of the present invention, the raw material rubber may include a solution-polymerized styrene-butadiene rubber.

The present invention also provides a heavy duty tire comprising the above-mentioned heavy-duty tire rubber composition.

According to the present invention, it is possible to improve the bonding property between the heavy-use tire rubber composition and the reinforcing material, thereby securing proper physical properties favorable to the fuel-efficient tire performance and improving the abrasion resistance.

Hereinafter, the present invention will be described in detail.

It is noted that the technical terms used in the present invention are used only to describe specific embodiments and are not intended to limit the present invention.

In addition, the technical terms used in the present invention should be construed in a sense generally understood by a person having ordinary skill in the art to which the present invention belongs, unless otherwise defined in the present invention, Or technical terms used in the present invention are erroneous technical terms that do not accurately represent the spirit of the present invention, it is to be understood that the technical terms used herein are not to be construed in a technical sense And the generic term used in the present invention should be construed in accordance with the predefined or prior context and should not be construed in an excessively reduced meaning, The expression of the plural, unless the context clearly dictates otherwise. In the present invention, terms such as "comprising" or "comprising" and the like should not be construed as encompassing various elements or various steps of the invention, It should be understood that the steps may not be included, or may be further comprised of additional components or steps, and in the description of the present invention, if it is determined that the detailed description of the related art is not sufficient to overcome the gist of the present invention A detailed description thereof will be omitted.

The heavy-use tire rubber composition according to the present invention is characterized in that it comprises a raw material rubber and a sulfate-based process aid capable of reacting with a double bond of carbon black and the raw rubber as a reinforcing material and capable of forming an amide bond with carbon black.

 The sulfate-based process aid may react with a carboxyl group present on the surface of the carbon black to form an amide bond, and the sulfate group may react with the double bond of the starting rubber, because the terminal group is modified with an amine group.

The raw rubber refers to natural rubber or synthetic rubber, and is not particularly limited as long as it is a rubber used for heavy duty tires. However, the carbon double-bond, which exists in the chemical structure of rubber, Since the double bond must be efficiently reacted to a single bond, a rubber having less steric hindrance at the double bond reaction position can be relatively advantageous.

For example, as shown in Scheme 1 below, when the sulfate group reacts with the double bond, proximity of the sulfate group to the double bond should be secured. When the double bond carbon is present in the methylene group or the styrene group, Probability can be lowered.

<Reaction Scheme 1>

In addition, carbon black is used as the reinforcing material for the raw rubber, and the surface of the carbon black is naturally oxidized to a carboxyl group or a carbonyl group, and reacts with amine groups modified at the end of the process preparation to form a chemical bond can do.

Here, in the case of a carbonyl group, the carboxyl group can be oxidized to a carboxyl group by the stearic acid contained in the rubber compound in a high temperature and high pressure tire rubber compounding process, and the carboxyl group and the amine group react with each other to form an amide bond, . &Lt; / RTI &gt;

As such, it is possible to use all of them without particular limitation as long as it is a process preparation capable of reacting with the double bond of the raw rubber of the rubber composition and capable of forming an amide bond with carbon black, and a sulfate-based process preparation is preferable.

The sulfate-based process aid may have reactivity with a double bond of a tire raw material rubber having a sulfate group (SO ₃ H) and an amine group (amine, -NH ₂ ) at one end of the compound and react with carbon black Amide bond.

As an example thereof, a process aid of the following chemical formula 1 can be mentioned.

&Lt; Formula 1 >

H ₂ N- (CH ₂ ) _x -SO ₄ H

(X: 8 or more, an integer of 20 or less)

The length of the carbon chain in the process aid may be limited to 8 to 20, which takes account of dispersibility, viscosity and aging properties in the rubber composition. If the number of hydrocarbons is less than 8, However, since the molecular weight is small and the movement is free, blooming phenomenon occurs and there is a fear of deterioration of the aging properties of the rubber. Conversely, when the number of hydrocarbons exceeds 20, the molecular weight is large and the length of the carbon chain becomes longer The initial and aging properties of the rubber may be helpful, but may increase the viscosity and interfere with dispersion.

In addition, the reinforcing material may further include silica. Through the silica, abrasion resistance and fuel consumption characteristics can be enhanced. In addition to natural rubber, a solution-polymerized styrene-butadiene rubber can be used to ensure dispersibility in the rubber composition. The solution-polymerized styrene-butadiene rubber used in the rubber composition may be modified with a chemical functional group having reactivity with carbon black and silica which are reinforcing agents at the ends.

The solution-polymerized styrene-butadiene rubber not only contributes to the dispersion of carbon black and silica, but also has excellent reactivity with the above-described process aid.

Table 1 below is a table showing test results of tire rubber manufactured in accordance with the composition and composition thereof in order to produce a heavy-duty tire rubber composition according to the present invention.

In Comparative Example 1, natural rubber was used, and Comparative Example 2 was made by changing the composition of rubber. In Comparative Example 1, Comparative Example 2 was evaluated by changing the rubber composition to improve the wear performance and the fuel consumption performance. However, in order to compensate for the deterioration of physical properties and viscosity characteristics, a sulfate-based process aid is added.

The results of each test were based on the ASTM evaluation method. As a result of the evaluation, indexes were used for both Mooney viscosity, dispersion degree, HD's, 300% M, tensile strength, DIN and RR. , And the larger the value, the better the performance.

                                             Unit: parts by weight (phr) Comparative Example 1 Comparative Example 2 Example 1 Example 2 Example 3 Example 4 Example 5 Natural rubber (NR) 100 70 70 70 70 70 70 Solution-polymerized styrene butadiene rubber (f-SSBR) 30 30 30 30 30 30 HP130 35 35 35 35 35 35 35 200MP 10 10 10 10 10 10 10 Si-69 One One One One One One One ZnO 3 3 3 3 3 3 3 Stearic acid 3 3 3 3 3 3 3 6PPD 2 2 2 2 2 2 2 X3 1.5 X8 1.5 X15 1.5 X20 1.5 X25 1.5 Sulfur 1.5 1.5 1.5 1.5 1.5 1.5 1.5 TBBS One One One One One One One Mooney viscosity 120 100 113 110 108 103 98 Dispersion degree 105 100 110 112 115 110 102 HD's 100 100 100 100 100 100 100 300% M 107 100 102 108 115 112 110 The tensile strength 103 100 102 109 115 119 119 DIN 80 100 100 105 108 109 108 RR 95 100 103 105 108 105 100

* HP130: Carbon black (I ₂ adsorption amount of 115 mg / g, N ₂ S of 127 m ² / g, DBP adsorption of 135 cc / 100 g), 200 MP of silica (CTAB 200 m ² / g, BET 215 m ² / g) X2, X3, X8, X15, X20, X25: Process preparation H ₂ N- (CH ₂ ) _x -SO _{2 4} H to X, with 3, 8, 15, 20, and 25 carbon atoms, respectively.

The Mooney viscosity, the dispersion degree, the HD's, the 300% M, the tensile strength, the DIN and the RR were measured, and the value of the comparative example 2 was set to 100, Measured according to ASTM D2663, HD's: Shore A, measured according to ASTM D2240, measured according to ASTM D1666, ML (1 + 4), measured according to ASTM D1646, 300% M: means the modulus when the tensile strength test is 300% longer than the initial specimen length, measured according to ASTM D412, tensile strength: means the modulus when the specimen undergoes a fracture According to ASTM D412 Measured in accordance with ASTM D5963 in the DIN: wear test, RR means compound tangent @ 60 ° C, measured in accordance with ASTM D2231)

As shown in Table 1, when the solution-polymerized styrene-butadiene rubber is used, the DIN and RR performances are improved, but the viscosity is lowered and the processability is lowered. When the natural rubber is used alone, Reduction in the amount of the water-insoluble materials can be found through Comparative Examples 1 and 2.

On the other hand, the evaluation results of Examples 1 to 5 show that the Mooney viscosity is reduced and the processability is improved, and the same effect is obtained even when the carbon bodies have different lengths.

In addition, in the case of Examples, there is no influence on HD's, but the dispersibility of carbon black is improved and the reinforcing property is enhanced as compared with Comparative Example 2. As a result, 300% M and tensile strength values tend to be excellent, As a result of the evaluation, the abrasion performance was improved by decreasing the wear amount as the dispersibility was improved, and the effect was remarkable when the carbon body length was 8 or more and 20 or less.

In addition, the RR performance was evaluated by evaluating the dynamic viscoelasticity property, and the result of converting the tanD value of 70 degrees on the basis of Comparative Example 2 shows that the RR performance is improved by the dispersion improvement in the case of the embodiment, In the case of Example 5, which is more than 20, the improvement effect is somewhat reduced.

In addition, the results of Examples 1 to 5 show that when a sulfate-based processing aid having a carbon-affinity terminal group is added, it functions as a processing oil in a liquid state under the same mixing conditions to reduce the Mooney viscosity and improve the dispersibility of carbon black Butadiene rubber alone, which is superior to Comparative Examples 1 and 2. It can be seen that the length of the hydrocarbon is 3% The Mooney viscosity decreased significantly, but the effect on the remaining performance was negligible. When the length of the carbonization chain was long, the flow rate of the process aid itself was disadvantageously increased to 25 ° C. In this case, the Mooney viscosity was increased and the distance between the rubber and carbon black was increased And the RR improvement effect is reduced.

In particular, the results of Examples 2 to 4 show that the problem of poor processability occurring when the solution-polymerized styrene-butadiene is solely applied is improved and the wear and RR performance are simultaneously improved.

Claims (5)

Carbon black as raw material rubber and reinforcing material,
And H ₂ N- (CH ₂ ) _x -SO ₄ H capable of reacting with the double bond of the raw material rubber and capable of forming an amide bond with carbon black.
(X: 8 or more, an integer of 20 or less) The method according to claim 1,
Wherein the carbon black has a carboxyl group on the surface thereof.
delete The method according to claim 1,
Wherein the raw material rubber contains a solution-polymerized styrene-butadiene rubber.
A heavy duty tire comprising a tire rubber composition for heavy duty according to any one of claims 1, 2 and 4.