JP3095264B2 - Rubber composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition applicable to various rubber products such as tires, vibration-proof rubbers and fenders. The present invention relates to a rubber composition particularly suitable for a tread of a pneumatic tire having excellent grip performance.

[0002]

2. Description of the Related Art Recently, demands for pneumatic tires having high kinetic performance have been increasing with the improvement of automobile performance, pavement of roads, and development of a highway network. In particular, grip performance is an important required characteristic, and is represented by acceleration performance and braking performance.

[0003] Accordingly, the higher these characteristics are, the more accurately and safely the vehicle can travel. Conventionally, in order to obtain high grip performance, styrene-butadiene having a high styrene content has been used as a tire tread rubber composition.
Select the error down copolymer rubber (rubber a high glass transition temperature), or a process oil and carbon black and select highly filled with formulation system, it is necessary to increase the tanδ of the rubber composition.

[0004] As a method for improving the accompanying grip performance degradation in temperature rise, in JP-A-59-187,011, 1,3 butadiene et emissions, a monomer such as styrene or isoprene, diphenyl -2 Use of a copolymer rubber obtained by copolymerizing an acrylate or methacrylate compound containing a diphenyl phosphate group, such as methacryloyloxyethyl phosphate or diphenyl-2-acryloyloxyethyl phosphate, is described.

[0005]

To obtain a high grip performance [0005], styrene - butadiene et when down copolymer increases the styrene content of, certainly grip performance becomes high,
As the rubber temperature rises due to tire running, ta
There has been a problem that the nδ value decreases and the grip performance sharply decreases.

On the other hand, although the grip performance is improved by the high filling of the process oil or the carbon black, the high filling has a limit, and if the filling is too high, the breaking characteristics and the wear resistance are remarkably reduced. there were.

The method disclosed in Japanese Patent Application Laid-Open No. 187011/1984 to improve the grip performance deterioration due to the above-mentioned temperature rise is not only applicable to natural rubber, but also depends on the production conditions. butadiene-et-down copolymer rubber, there is a problem that impairs the nature should be the original Yu Poributaji d Ngomu.

The object of the present invention is to be effective when blended with natural rubber, synthetic rubber, and mixed rubber thereof. The grip performance does not decrease even when the temperature of the rubber rises. An object of the present invention is to provide a rubber composition having excellent grip performance, in which a grip performance improving agent which does not impair the wear performance and does not impair the performance of the rubber itself is blended.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems, and as a result, have been disclosed in
JP-A-3-10645 has provided a rubber composition containing an imidazole compound and / or an imidazoline compound.

As a result of further study, it was confirmed that these problems could be solved by adding a specific amount of a specific urea compound to the rubber composition, and the present invention was completed.
Furthermore, they have found that by blending a specific amount of the urea compound whose average particle size is adjusted to a small particle size, it is possible to solve these problems without lowering the breaking limit, and completed the present invention.

That is, the present invention relates to natural rubber, and / or
Or at least 100 parts by weight of rubber made of synthetic rubber,
Directly bonded to an aryl group represented by the general formula (1)
At least one of the urea compounds having two or more nitrogen atoms
It is a rubber composition containing 0.1 to 100 parts by weight of a seed.

Embedded image (Wherein, R ₁ represents an alkyl group, a benzyl group, an aryl group, and R ₂ represents urea .)

The present invention also relates to a natural rubber and / or a synthetic rubber.
100 parts by weight of rubber represented by general formula (2)
Has two or more nitrogen atoms directly bonded to the aryl group
At least one of the urea compounds is
It is a rubber composition formulated by weight .

Embedded image (Where R ₁ is an alkyl group, a benzyl group, an aryl group, and Ar is any of the following structural formulas (a), (b) and (c))
Indicate this)

Embedded image Further, the present invention provides the above-mentioned general formula (1) or (2), or
Adjusting at least one of the urea compounds represented by the chemical formulas (3) to (6) to an average particle size of 1.5 μm or less,
It is a rubber composition mixed with 0.1 to 100 parts by weight.

In the present invention, as the rubber component, natural rubber or synthetic rubber can be used alone or in combination. As the synthetic rubber synthetic polyisoprene rubber, Poributaji et Ngomu and Suchirenbutaji
D Ngomu the like can be exemplified.

The urea compound represented by the general formula (1) or (2) , which is a grip performance improver characteristic of the present invention, includes:

Embedded image

Embedded image

Embedded image

Embedded image Etc. can be exemplified.

According to the present invention, the compound represented by the general formula (1) or (2) is added to 100 parts by weight of the rubber component.
A rubber composition obtained by blending 0.1 parts by weight, but the amount can not be improved grip performance for the purpose of the present invention is less than 0.1 part by weight. On the other hand, if the compounding amount exceeds 100 parts by weight, not only the effect corresponding to the increased amount is not obtained, but also various physical properties after vulcanization are adversely affected, resulting in undesirable results. Therefore, in order to sufficiently exhibit the desired effects of the present invention, the compound is added in an amount of 1 to 8 with respect to 100 parts by weight of the rubber component.
It is preferable to mix 0 parts by weight, more preferably 3 to 60 parts by weight. More books
In the invention, the above-mentioned general formula (1) or (2) or a chemical formula
At least one of the urea compounds represented by (3) to (6)
One kind is adjusted to an average particle size of 1.5 μm or less and blended.
Tanδ (50) without lowering the fracture limit.
C) can be greatly increased.
desirable.

In the present invention, the above general formula (1) or
In addition to the urea compound represented by (2) and the like, rubber compounding agents usually used in the rubber industry, such as fillers, softeners, antioxidants, vulcanization accelerators, vulcanization accelerators, Vulcanizing agents and the like can be blended within the usual range as needed.

[0017]

The urea compound used in the present invention has the effect of increasing the interaction between rubber molecules, rubber molecules and filler particles (particularly carbon black particles), and between filler particles. By reducing the particle size of the urea compound, a decrease in the breaking limit is suppressed, and the above-mentioned interaction is increased. This allows high temperatures,
It is considered that a rubber composition having a large tan δ value can be obtained while maintaining a high breaking limit as compared with a large particle urea compound.

[0018]

The present invention will be described in more detail with reference to the following examples, but the present invention is not limited to these examples.

The urea compounds used in the following examples are as follows. Urea compound (1)

Embedded image Urea compound (2)

Embedded image Urea compound (3)

Embedded image Urea compound (4)

Embedded image

(Examples 1 to 7, Comparative Examples 1 and 2) The raw materials shown in Table 1 were blended in a Banbury mixer and vulcanized. The obtained vulcanized product was measured for tan δ at 50 ° C. under the condition of a dynamic strain of 1% using a spectrometer manufactured by Iwamoto Seisakusho. The urea compound used here is a compound having a mixed particle size without sorting the average particle size. The obtained results are shown in the lower part of Tables 1 and 2. From the results in Tables 1 and 2 below, all of the rubber compositions of the present invention shown in Examples have a value of tan δ (50 ° C.) as compared with the rubber composition containing no urea compound of Comparative Example 1. You can see that it is getting bigger.

[0021]

[Table 1]

[Table 2]

Next, a mixture of the rubber compositions of Examples 1 to 4 and 7 with an average particle size of the urea compound of 1.5 μm or less, particularly 0.4 to 0.5 μm was used. Small particle size Examples 8 to 12 with an average particle size of 1.5 μm
Examples of ultra-large particles, particularly those having a size of 1.7 to 2.0 μm, were used as large particle size examples (8) to (12), and the obtained vulcanized products were measured using a spectrometer manufactured by Iwamoto Seisakusho Tan δ at 50 ° C. under the condition of 1% dynamic strain
Was measured. Regarding the breaking limit, see JISK630.
1 and the elongation at break was compared.

The results obtained are shown in Tables 3 and 4. Table 3,
From the results in Table 4, the rubber compositions containing the urea compounds having the small particle diameters in Examples 8 to 12 having the small particle diameters are all urea compound-containing rubbers having large particle diameters (Examples of large particle diameters (8) to (8)). 1
2)), without lowering the fracture limit, ta
It can be seen that the value of nδ (50 ° C.) can be greatly increased.

[0024]

[Table 3]

[Table 4]

[0025] (small particle size Examples 13 to 16, large particle size Example (13) to (16)) Styrene content 35% rate styrene - butadiene et Ngomu 10
0 parts by weight, ISAF carbon black 80 parts by weight, aroma oil 100 parts by weight, stearic acid 1 part by weight, antioxidant (6C) 1 part by weight, zinc white 3 parts by weight, vulcanization accelerator DPG 0.3 part by weight And a rubber composition containing 0.7 parts by weight of a vulcanization accelerator DM and 1.5 parts by weight of sulfur in a rubber composition containing the above urea compounds (1) to (4) having a reduced particle size (average particle size of 0.4 to 0. 6 μm and a large particle size (average particle size 1.7 to
2.0 μm) in each of the rubber compositions containing 20 parts by weight of each of the small particle diameter examples 13 to 16 and the large particle diameter examples (13).
To (16).

Using this rubber composition, a size 205 / 515-13 (for front wheels) 225 /
515-13 (for rear wheels) tires were prepared. Using these tires, the vehicle ran on a circuit of 4.41 km per lap at as high a speed as possible, and measured the lap times on laps 10 to 20 to determine the best time at that time. In addition, 10 to 20 of tires (Comparative Example 3) produced in the same manner as in the above Example without blending the urea compound in the present invention.
Tables 5 and 6 show the results of indexing the best lap time of the lap and setting this as 100. Here, the larger the value, the faster the lap time and the better the grip performance in high-speed running.

[0027]

[Table 5]

[Table 6]

From the results shown in Tables 5 and 6, it can be seen that the gripping performance of the compounded material having a small particle size is larger than that of the compounded system having a large particle size.

[0029]

The rubber compositions containing the urea compound of the present invention all have a large tan δ, and are superior in grip performance to tires in an elevated temperature state as compared with the same rubber composition containing no urea compound. In particular, an average particle size of 1.5μ
The rubber composition containing the urea compound adjusted to be equal to or less than m has a better grip performance with a tire in a temperature-raised state than the rubber composition containing the large-diameter urea compound. Therefore, it can be suitably used as a rubber composition for pneumatic tires having high athletic performance, and as a rubber composition for vibration control and fenders.

────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-4-126737 (JP, A) JP-A-3-199250 (JP, A) JP-B-47-29576 (JP, B1) JP-B-47-47 29575 (JP, B1) (58) Field surveyed (Int. Cl. ⁷ , DB name) C08L 21/00 C08K 5/21

Claims (7)

(57) [Claims] 1. An aryl represented by the general formula (1) in 100 parts by weight of a rubber composed of natural rubber and / or synthetic rubber.
At least one kind of rubber composition obtained by blending 0.1 to 100 parts by weight of a nitrogen atom bonded directly to the group urea compounds <br/> compound having two or more. Embedded image (Where R ₁ represents an alkyl group, a benzyl group, an aryl group, and R ₂ represents urea ) 2. An aryl represented by the general formula (2) is added to 100 parts by weight of a rubber composed of natural rubber and / or synthetic rubber.
Urea compounds having two or more nitrogen atoms directly bonded to a group
At least one of the ingredients is blended in an amount of 0.1 to 100 parts by weight
Rubber composition. Embedded image (Where R ₁ is an alkyl group, a benzyl group, an aryl
The group Ar is any of the following structural formulas (a), (b) and (c)
This is shown below. 3. The urea compound represented by the chemical formula (3):
The rubber composition according to claim 1, which is a rubber composition. Embedded image 4. A urea compound represented by the formula (4):
The rubber composition according to claim 1, which is a rubber composition. Embedded image 5. The urea compound represented by the chemical formula (5):
The rubber composition according to claim 1, which is a rubber composition. Embedded image 6. The urea compound represented by the chemical formula (6):
The rubber composition according to claim 1, which is a rubber composition. Embedded image 7. A urea compound having an average particle size of 1.5 μm
The method according to any one of claims 1 to 6, wherein the composition is adjusted and blended as follows .
2. The rubber composition according to item 1.