JPH059338A - High grip grade rubber composition - Google Patents

Abstract

PURPOSE:To obtain the title composition improved in grip performance while maintaining abrasion resistance by blending a specific styrene-butadiene copolymer rubber with a petroleum resin in a specific amount. CONSTITUTION:The objective composition containing (A) 100 pts.wt. styrene- butadiene copolymer rubber having 25-60wt.% (preferably <=45%) styrene component content and (B) 10-50 pts.wt. (preferably 20-40 pts.wt.) petroleum resin, consisting essentially of 9C aromatic resin, preferably having 80-140 deg.C softening point.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a tread rubber composition having high grip performance. More specifically, it relates to a tread rubber composition exhibiting high grip performance without deteriorating wear resistance.

[0002]

2. Description of the Related Art Treads of tires used for racing on paved road surfaces such as circuits are required to have high grip performance. Conventionally, in order to obtain this high grip performance, a method of using a styrene-butadiene copolymer rubber having a high styrene component content as a polymer, a method of highly compounding a softening agent, and a compounding system highly filled with carbon black are used. There is a method and a method of using carbon black having a small particle diameter, and a rubber composition for a tread having a high grip performance has been obtained by combining these methods.

However, generally, the use of a styrene-butadiene copolymer rubber having a high styrene content lowers the wear resistance, and it is not possible to use carbon black having a small particle size or a large amount of a softening agent. However, there is a problem that the dispersion of carbon black is adversely affected and the abrasion resistance is further reduced.

[0004]

SUMMARY OF THE INVENTION An object of the present invention is to provide a rubber composition for a tread which has a high grip performance without deteriorating wear resistance.

[0005]

The present inventors have completed the present invention as a result of earnestly researching in order to solve the above-mentioned problems by paying attention to a resin compounded in rubber. That is, the present invention contains 10 to 50 parts by weight of a petroleum resin containing a C ₉ aromatic resin as a main component based on 100 parts by weight of a styrene-butadiene copolymer rubber having a styrene content of 25 to 60% by weight. It is a tread rubber composition having a high grip property.

The present invention will be described in detail below. A petroleum resin containing a C ₉ aromatic resin as a main component is a resin obtained by polymerizing an aromatic fraction having 9 carbon atoms and containing vinyltoluene and indene as main monomers, and is traded by Mitsui Petrochemical Co., Ltd. Petrozine, Mikuni Chemical Petroleum, Nippon Petrochemical Neopolymer, Toyo Soda Petcoal, etc.

The C ₉ aromatic petroleum resin has a softening point of 80 to 1
Those having a temperature of about 40 ° C. are preferable because the rate of increase in grip is large. The compounding amount of C ₉ aromatic petroleum resin is rubber 1
If it is blended in an amount of more than 50 parts by weight with respect to 00 parts by weight, the abrasion resistance is lowered, which is not preferable. If the amount is less than 10 parts by weight, the effect of improving grip performance cannot be obtained. C ₉
Considering high grip performance and abrasion resistance, the aromatic petroleum resin is preferably mixed in an amount of 20 to 40 parts by weight with respect to 100 parts by weight of the rubber.

The content of the styrene component of the styrene-butadiene copolymer rubber of the polymer is 25 to 60% by weight. However, considering that the abrasion resistance decreases when the styrene component increases, the content of 45% by weight or less is preferable. preferable.

As described above, the gist of the present invention is to blend a C ₉ aromatic petroleum resin into a styrene-butadiene copolymer rubber. By blending this resin, the loss tangent ( Even if the tan δ) becomes large and the styrene component content of the polymer is reduced, the same high grip performance can be obtained, so that there is an advantage that the problem of deterioration of abrasion resistance, which is a defect of the tread rubber containing a high styrene component, can be solved.

Since this resin also has the effect of lowering the elastic modulus after vulcanization, the amount of the softening agent can be reduced, and the dispersion of carbon black having a small particle size can be improved.

[0011]

EXAMPLES The present invention will be described in more detail with reference to Examples and Comparative Examples of the present invention, but the present invention is not limited to these Examples.

(Examples 1 to 7) (Comparative Examples 1 to 4) A styrene-butadiene copolymer rubber (SB) was prepared by using Petrosin manufactured by Mitsui Petrochemical as a C ₉ aromatic petroleum resin.
The tread rubbers of Examples 1 to 7 having the compounding ratios shown in Tables 1 and 2 were prepared by using the R) having a styrene component content of each weight% shown in Tables 1 and 2 and evaluated. went.

As comparative examples, comparative examples 1 to 3 in which a conventional softening agent is used in a large amount, and 5 parts by weight of the C ₉ aromatic petroleum resin of the present invention in an amount less than 10 parts by weight. Comparative Example 4 of a part was prepared and evaluated in the same manner.

The evaluation was carried out on a circuit consisting of 4.4 km per lap. Here, the grip means the average lap time from the 10th to the 20th laps, and the time of the control tire is 10
It is expressed as an index of 0. When it is larger than 100, the grip is high, and when it is smaller than 100, the grip is poor.

The abrasion resistance is an index of the abrasion of the control tire, which is similarly measured and averaged after running 20 times around the circuit at three places around the tire, as an index. With respect to the wear resistance as well, a wear resistance of more than 100 indicates good wear resistance, and a wear resistance of less than 100 indicates poor wear resistance. The blending and evaluation results are shown in Tables 1 and 2.

[0016]

[Table 1]

[Table 2]

In Examples 1 to 7, the grip is improved as compared with Comparative Example 1. Further, Example 1, Comparative Example 2, and Example 2
Comparison between Comparative Example 3 and Comparative Example 3 shows that the example has a small amount of styrene component and maintains a grip equivalent to that of the comparative example, and the abrasion resistance is improved by blending the C ₉ aromatic petroleum resin. is doing.

As shown in Example 7, the resin using a resin having a softening point of 60 ° C. has a slight grip improving effect, but is slightly
The softening point is preferably higher than 60 ° C. Further, comparing Examples 2, 5 and 6 with Comparative Example 1, it can be seen that grip performance and abrasion resistance are improved.

In comparison with the comparative example, Example 4 has very high grip performance, but inferior wear resistance. Therefore, the amount of resin used is preferably 10 to 40 parts by weight, irrespective of the demand for high grip performance at the expense of wear resistance.

In Comparative Example 4, only performance equivalent to that of Comparative Example 1 was obtained. That is, even if the C ₉ aromatic petroleum resin is blended, the effect is not recognized if it is less than 10 parts by weight. As described above, the tread rubber composition of the present invention has the effect of improving the grip performance while maintaining the wear resistance, as is clear from Tables 1 and 2.

[0021]

EFFECT OF THE INVENTION Styrene-butadiene copolymer rubber 10
By adding 10 to 50 parts by weight of C ₉ aromatic petroleum resin to 0 part by weight, while maintaining abrasion resistance,
A rubber composition for a tread having improved grip performance was obtained.

Claims (1)

Claims: 1. The styrene content is 25 to 60% by weight.
To 100 parts by weight of the styrene-butadiene copolymer rubber of 10 to 5 petroleum resins containing a C ₉ aromatic resin as a main component
A high-grip tread rubber composition containing 0 part by weight.