KR100542276B1 - Hard apex Rubber compound for truck and bus tire - Google Patents

Abstract

The present invention relates to a hard apex rubber composition of a tire for trucks and buses, wherein 2.0 to 3.5 parts by weight of sulfur is applied to 100 parts by weight of natural rubber, and an application ratio of sulfur (A) to sulfenamide-based accelerator (B) / B) of 1.0 to 1.9 results in a price drop without compromising modulus, revision and flex resistance.

Hard Apex, Sulfenamide Accelerator, Modulus

Description

Hard apex rubber compound for truck and bus tires

The present invention relates to a hard apex rubber composition of a tire for trucks and buses, and more particularly, to a truck having excellent price performance without deteriorating other performance by appropriately combining sulfur and sulfenamide accelerators without adding expensive adhesives and adhesion aids. A hard apex rubber composition for a tire for a bus.

The required characteristics of automotive tires vary greatly depending on the parts of the tire or the use of the tire.

In particular, the hard apex rubber, which is firmly held on the bead of the tire to hold the bead portion not to move and minimizes the flow of the bead even after the rim and the mounting, requires a high modulus.

In general, carbon black, which is a reinforcing agent, is applied to increase the modulus. However, when a large amount of carbon black is applied as described above, the workability of the rubber becomes poor.

In order to solve the above problems, an adhesive (Resorcinol Formaldehyde Resin) and an adhesive aid (Hexa-Nethoxy-Methl-Melamine; HMMM) are applied.

However, the cost of the adhesive and the adhesion aid is high, which is a factor that increases the price of rubber.

In order to solve the problems of the prior art as described above, in the hard-apex rubber composition of truck and bus tires, sulfur and an accelerator are suitably combined with 100 parts by weight of natural rubber to avoid adding expensive adhesives and adhesion aids. The aim is to provide a hard-apex rubber composition for tires for trucks and buses, which is excellent in price performance without compromising performance.

In order to achieve the above object, the present invention, in the hard apex rubber composition of known tires for trucks and buses, sulfur 2.0 to 3.5 parts by weight based on 100 parts by weight of natural rubber, sulfur (A) versus sulfenamide-based accelerator ( The application ratio (A / B) of B) is 1.0 to 1.9.

The sulfenamide-based accelerators include N-cyclohexyl-2-benzothiazolesulfenamide (CBS), N-oxydiethylene-2-benzothiazolesulfenamide (OBS) and Nt-butyl-2-benzothiazolesulfenamide (BBS), N, N-diisopropyl-2-benzothiazolesulfenamide, and the like.

Sulfur applied to the rubber composition of the present invention is preferably 2.0 to 3.5 parts by weight based on 100 parts by weight of natural rubber. When the sulfur is applied less than 2.0 parts by weight, the modulus decreases, and when it is applied by more than 3.5 parts by weight, the scorch time (T5) is shortened and the reversion phenomenon is increased, resulting in a problem of deteriorating physical properties after aging. .

In the present invention, the amount of sulfur used versus the amount of sulfenamide-based accelerator is preferably 1.0 to 1.9. When the amount of sulfur used versus the amount of sulfenamide-based accelerator is less than 1.0, mono-sulfide bonds increase, resulting in a decrease in bending resistance. In addition, when the amount of sulfur used versus the amount of sulfenamide-based accelerator is larger than 1.9, a reversion phenomenon becomes large, resulting in a problem of deterioration of rubber properties.

Hereinafter, the present invention will be described in more detail with reference to Examples and Comparative Examples. However, the present invention is not limited to these examples.

Comparative Example

As shown in Table 1, the present invention is based on 100 parts by weight of natural rubber, carbon black 65 parts by weight, zinc oxide 5 parts by weight, stearic acid 2 parts by weight, process oil 5 parts by weight, antioxidant 1 part by weight, adhesive 1.5 By weight, 3 parts by weight of the adhesive aid, 1.5 parts by weight of sulfur, 1.0 parts by weight of sulfenamide promoter was mixed, and then a hard-apex rubber specimen was prepared using a Banbury mixer.

<Example 1>

A rubber specimen was prepared using the same composition, composition ratio, and method as in Comparative Example, except that no adhesive and an adhesive assistant were added.

<Example 2>

The rubber specimen was prepared by using the same composition, composition ratio, and method as in Comparative Example, except that 2.5 parts by weight of sulfur was not added.

<Example 3>

A rubber specimen was prepared using the same composition, composition, and method as in Comparative Example, except that 2.5 parts by weight of sulfur and 3.5 parts by weight of sulfenamide accelerator were not added.

<Example 4>

A rubber specimen was prepared using the same composition, composition, and method as in Comparative Example, except that 2.5 parts by weight of sulfur and 2.0 parts by weight of sulfenamide accelerator were not added.

TABLE 1 Tread rubber compositions of Comparative Examples and Examples 1-4

Comparative example Example 1 Example 2 Example 3 Example 4 Natural rubber 100 100 100 100 100 Carbon black 65 65 65 65 65 Zinc oxide 5 5 5 5 5 Stearic acid 2 2 2 2 2 Process oil 5 5 5 5 5 Antioxidant One One One One One glue 1.5 0 0 0 0 Adhesion Aids 3 0 0 0 0 sulfur 1.5 1.5 2.5 2.5 2.5 Sulfenamide accelerators 1.0 1.0 1.0 1.0 1.0

<Test Example>

The physical properties of the rubber samples of Comparative Examples and Examples 1 to 4 were measured by ASTM-related regulations, and the results are shown in Table 2 below.

The example shown in Table 2 below shows a relative value based on the comparative example, indicating that the larger the value is, the better.

<Table 2> Measurement results of physical properties of Comparative Example and Example 1-4

Property Comparative example Example 1 Example 2 Example 3 Example 4 Modulus 100 77 92 100 100 price 100 143 147 137 144 Revision 100 95 76 105 100 Flex resistance 100 99 107 80 100

As shown in Table 2, the physical property measurement results are as follows.

First, in the case of Example 1 in which the adhesive and the adhesive auxiliary agent is excluded from the rubber composition of the comparative example, it can be seen that the modulus, revision, and flex resistance except the cost performance are lower than those of the comparative example 1.

Second, when comparing the Comparative Example and Example 2, it can be seen that Example 2 is significantly reduced in the modulus performance and the reversion performance than the Comparative Example.

Third, Example 3 has better performance than the comparative example but it can be seen that the flex resistance is greatly reduced.

Fourth, compared with the comparative example, Example 4 has the same modulus, flex resistance, and reversion performance, but it is excellent in price performance.

In summary, according to Table 2, the present invention applies 2.0 to 3.5 parts by weight of sulfur to 100 parts by weight of natural rubber, and the application ratio (A / B) of sulfur (A) to sulfenamide-based accelerator (B) is From 1.0 to 1.9, we can see that the price performance is greatly improved without any other performance drop.

As shown in Table 2, which is the result of the above test example, the present invention is suitable for applying sulfur and accelerators without applying expensive adhesives and adhesive aids to 100 parts by weight of natural rubber in hard-apex rubber compositions for truck and bus tires. The combination results in a price down without a drop in modulus, revision and flex resistance.

Claims (1)

In the hard-apex rubber composition of tires for trucks and buses, which does not use adhesives and adhesive aids, 2.0 to 3.5 parts by weight of sulfur based on 100 parts by weight of natural rubber, and the application ratio (A / B) of sulfur (A) to sulfenamide-based accelerator (B) is 1.0 to 1.9, wherein the tires for trucks and buses Hard Apex rubber composition.