JP2001123017A - Rubber composition for tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rubber composition for obtaining a tire which shows a good ground-contacting property to snowy or icy roadbeds, shows an excellent frictional force on ice and requires short braking distance. SOLUTION: A rubber composition for tires is prepared by compounding from 20 to 60 pts.wt. carbon black with <=30 pts.wt. silica against 100 pts.wt. rubber component, wherein the total amount of carbon black and silica is from 40 to 60 pts.wt. Here, from 1 to 10 pts.wt. fraipontite/silica complex is further compounded against 100 pts.wt. rubber, and a JIS hardness ( -5 deg.C) of a vulcanized product, measured according to JIS K6253, of from 50 to 60 [tires for PC(passenger cars)] oor from 60 to 70 [tires for TB(trucks and buses)] is achieved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a rubber composition for tires, and more particularly, to a rubber composition for tires of vehicles such as trucks, buses, light trucks, and passenger cars, which is suitable for traveling on snowy and iced roads. The present invention relates to a rubber composition used for a tread.

[0002]

2. Description of the Related Art Conventionally, tread rubber of a studless tire of a passenger car has a low rubber hardness at a low temperature (50 to 60 °: JIS) in order to enhance the contact with snow and ice on a road surface. In order to further increase the frictional force on ice, techniques such as the use of foamed rubber, the blending of hollow particles, or the blending of vegetable particles such as walnut shells have been proposed.

The former technology for lowering the rubber hardness at low temperatures to improve the contact with snow and ice on a road surface has reached a satisfactory level to some extent, but the latter technology for increasing the frictional force on ice has been achieved. In fact, it was not yet at a satisfactory level. That is, when foamed rubber is used for the tire tread, a water film (a water film generated by frictional heat between a road surface on ice and a tire) is removed by a hole (recess) formed on the surface, thereby Although it is expected to increase the frictional force on ice, in fact, the above-mentioned holes do not have the water film removing performance as expected and have not reached the level required in the market.

In the case of using hollow particles, it is expected that the water film is taken into the hollow portion of the particle to increase the frictional force on ice, but the transfer of the water film to the hollow portion takes some time. However, there is a problem that the water particles are required, and the hollow particles are broken at the time of molding the tire. As described above, the water film removing performance as expected was not exhibited, and the market did not reach the required level.

[0005] Further, when using vegetable granular material,
There is no problem in terms of environment, health and safety, it has the effect of scratching ice, and although it is one effective means as an anti-slip agent, the fact is that it has not yet reached a sufficient level.

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and has as its object to provide good ground contact with snow and ice road surfaces, excellent frictional force on ice, and a short braking distance. It is an object of the present invention to provide a rubber composition for obtaining a tire.

[0007]

A rubber composition for a tire according to claim 1 of the present application (a tire rubber composition for a PC (for a passenger car)).
Means 100 parts by weight of the rubber component (hereinafter simply referred to as "parts")
To 60 to 60 parts of carbon black and 30 parts of silica
Parts or less, the total amount of carbon black and silica is 40 to 6
0 parts of a vulcanizate having a JIS hardness (＠ −5 ° C.) of 50 to 60 as measured according to JIS K6253.
It is characterized by containing a silica composite.

[0008] The "JIS hardness (＠ -5 ° C)" means
It means that the measurement temperature is −5 ° C. for both the atmosphere and the sample (the same applies hereinafter).

The rubber composition for a tire according to claim 2 of the present application (TB)
Tire rubber composition (for heavy loads such as trucks and buses)
Represents carbon black 20 per 100 parts of the rubber component.
-60 parts, 30 parts or less of silica, and 40-60 parts of the total amount of carbon black and silica are blended.
JIS hardness (＠ -5 ° C) of the vulcanizate measured according to 3
Is a rubber composition for tires having a particle size of from 60 to 70, further comprising a flypontite-silica composite.

It is preferable that the compounding ratio of the frypontite-silica composite to 100 parts of rubber is 1 to 10 parts.

Furthermore, it is preferable that vegetable granules such as ground walnut shells are blended (claim 4).

[0012]

As the rubber component used in the rubber component present invention aspects of the practice of the present invention, the usual rubber used in tire rubber composition is used, specifically, natural rubber, SBR, BR, IR, chlorinated IIR And the like. These may be used alone or in combination of two or more.

The carbon black that can be used in the present invention is not particularly limited. For example, SAF grades having a number in the 100s and 20 having a large reinforcing property according to ASTM D1765 and 20 can be used.
There may be mentioned ISAF grades having a number in the 0s or equivalents, and specifically, N110, N121, N219, N
220, N231, N330, and N339 are exemplified.
These may be used alone or in combination of two or more.

[0014] Silica silica, dry silica (anhydrous silicic acid), such as wet silica (hydrous silicic acid), is not particularly limited as long as silicas such as are used in tire rubber compositions, for example, A rubber composition having a pH of 5% suspension water of less than 7.0 is suitably used.

[0015] Fly Pont Tight - silica composite fly Pont tight - Silica composite,

Embedded image (N is 0 to 3.5, preferably 0.6 to 2.0) Fine laminated plate-like crystal of fryponite (average particle) of aluminosilicate metal salt mainly composed of zinc salt represented by a chemical formula Diameter is about 0.5-20 μm, BET specific surface area is about 20-
In this case, a unit layer of 300 m ² / g) is supported around silica particles.

[0016] Regarding the method of producing franponite,
It is described in the official gazettes of Japanese Patent Publication No. 4-51485, Japanese Patent Publication No. 5-44405, and Japanese Patent Publication No. 5-44406. One example is described below. That is, a water-soluble silicate (eg, sodium silicate) is 5 to 45 mol% (in terms of SiO ₂ ),
35-65 mol% of water-soluble zinc salt (example: zinc chloride) (Zn
O) and a water-soluble aluminum salt and / or a water-soluble aluminate (eg, aluminum chloride, sodium aluminate) 0 to 60 mol% (in terms of Al ₂ O ₃ ) are mixed in the presence of moisture to cause double decomposition. Let react. Next, the resulting precipitate is subjected to the addition of 0.5 to 5 at about 50 to 110 ° C in the presence of moisture.
Heat for about an hour. As a result, synthetic flavonponite is obtained.

[0017] Fly Pont Tight - Typical examples of the silica complex, Mizukanaito HP the _{5ZnO · Al 2 O 3 · 3~4SiO} 2 was supported on amorphous silica, Mizukanaito AP (both Mizusawa Chemical Industry Co., Manufactured by Nihonbashi, Chuo-ku, Tokyo).

[0018] Flanpontite will be further described below. Flampontite is a microcrystal of a synthetic metal aluminosilicate (Zn, Mg) belonging to a 1: 1 type (two-layer structure) serpentine subgroup viscosity mineral. Generally, several to several tens layers of synthetic franponite crystals are used. The flavonponite of the flavonponite-silica fine particle composite used in the present invention is, for example, held in the gaps between the silica fine particles in a state where unit layers of crystals having a two-layer structure are dispersed one by one. Have been. Therefore, the acidity and the basicity generated on the front and back surfaces of the unit layer of flanponite independently coexist and form an amphoteric adsorption surface on one solid particle surface without neutralizing each other. The micro- and macro-pores (pores) in the silica fine particle matrix effectively act for the diffusion of the adsorbate into the inside of the particle, and the mild solid acidity of the surface of the silica fine particle is also taken into consideration. The composite becomes a hydrophilic porous adsorbent having both extremely large acid and base properties.

As described above, since both the front and back surfaces of the unit layer in flampontite have adsorption performance, the silica fine particles are kneaded with a mixture of flampontite and silica fine particles so that the adsorption surface of the unit layer becomes Adsorbed on the silica gel to obtain a frypontite-silica composite.

In recent years, snow melting agents (Na
Cl, CaCl ₂ , MgCl _2, etc.), but the frying-pontite-silica composite of the present invention is a hydrophilic porous material having both extremely large acid and base properties as described above. Effectively adsorbs such snow melting agents,
Can be removed.

Vegetable Granules Examples of the vegetable granules include ground shells of seeds such as walnut and crushed granules of fruit nuclei such as peach. The preferred range of the particle size of the granular material varies depending on the tire used and cannot be unconditionally determined, but is approximately 100 to 600 μm.
Within the range. When the thickness is less than 100 μm, when the rubber composition for a tire of the present invention is used for, for example, a tread, projections formed on the tread may become small and the scratching effect may be reduced.
When the number exceeds a certain value, the number of pieces having a certain weight decreases, the number of protrusions also decreases, and the scratching effect may be reduced.

The vegetable granules are used to improve the compatibility with the rubber (for the purpose of preventing the plant granules from falling off).
Preferably, it is treated with an adhesive. The method of adhesive treatment is not particularly limited. For example, the molar ratio of resorcinol to formalin is 1: 2 (resorcinol + formalin) and the solid content weight ratio of vinylpyridine latex is 1: 2.
6. An adhesive treatment method performed using the resorcinol-formalin latex (RFL) treatment liquid described in No. 6 so that the adhesion rate to the plant granules becomes 1 to 5% by weight (preferably 2 to 4% by weight).

On the surface of the tread formed of the rubber composition containing the granules, fine protrusions are formed, which effectively act as an anti-slip agent. By using the above-mentioned frypontite-silica composite and the vegetable granules in combination, the effect of the conventionally considered vegetable granules as an anti-slip agent is dramatically improved. The whole mechanism is not clear,
Finally, the fly-pontite-silica complex uniformly dispersed in rubber effectively adsorbs and removes a water film on the road surface on ice (water film generated by frictional heat between the road surface on ice and the tire). This is presumed to be because the effect of the plant granular material as an anti-slip agent was dramatically improved.

As described above, the granular material works as an anti-slip agent.
Vegetables are selected as softer and more environmentally friendly than asphalt.

The mixing ratio of carbon black and silica to 100 parts of the rubber component is 20 to 60 parts and 0 to 30 parts, respectively, and the sum (total amount) of both is 40 to 60 parts to 100 parts of rubber.
Department. Even if this total amount is less than 40 parts, 6
Even when the amount exceeds 0 parts, the balance between the slip resistance and the wear resistance is broken.

The mixing ratio of the frypontite-silica composite is preferably 1 to 10 parts with respect to 100 parts of the rubber component. If the amount is less than 1 part, the function and effect as expected cannot be obtained. If the amount exceeds 10 parts, the abrasion resistance may be reduced. In addition, a more preferable compounding ratio of the frupontite-silica composite is 2 to 5 parts with respect to 100 parts of the rubber component.

The mixing ratio of the vegetable granular material is preferably 0.1 to 10 parts with respect to 100 parts of the rubber component. When the amount of the plant-based granules is less than 0.1 part, the scratching effect is small, and the synergistic effect with the fripontite-silica composite cannot be expected much. If the amount exceeds 10 parts, the abrasion resistance may decrease.

[0028] Other rubber composition for a tire of the present invention may also be formulated compounds such as are normally added in addition to components as described above. That is, for example, compounds such as a vulcanizing agent, a vulcanization accelerator, zinc oxide, stearic acid, an antioxidant, an antioxidant, and an ozone deterioration inhibitor can be blended.

[0029]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below, but the present invention is not limited thereto.

Examples 1 to 10 and Comparative Examples 1 to 5 (PC
(Passenger car) Tires) The components shown in the following [Table 1] to [Table 3] were blended in the proportions shown in the table. Thereafter, the mixture was kneaded using a Banbury mixer according to a general method to obtain a rubber composition.

The obtained rubber composition is vulcanized at 160 ° C. for 20 minutes, and the JIS hardness (in an atmosphere of 物 -5 ° C.) of the vulcanized product is set to J.
It was measured in accordance with IS K6253. The Lambourn friction of the vulcanized product was measured according to JIS K6264. Further, a PC tire (185 / 70R14) having a tread formed from the obtained rubber composition was mounted on a vehicle, and a braking distance on ice was measured. The results are shown in each table.

[0032]

[Table 1] * 1: RSS # 1 * 2: BR01 (manufactured by JSR) * 3: Seast 6 (manufactured by Tokai Carbon) * 4: Nip seal AQ (manufactured by Nippon Silica) * 5: Process P-200 (manufactured by Japan Energy) * 6: Pulverized walnut shell (100 to 600 μm). Resorcinol / formalin 1: 2 (molar ratio) (resorcinol + formalin) and vinylpyridine latex with a solids weight ratio of 1: 6, resorcinol / formalin / latex treatment liquid (RFL treatment liquid), adheres to vegetable granules The adhesive treatment was performed so that the ratio became 2% by weight. * 7: Walnut shell pulverized product (average 80 μm). * 8: The same adhesive treatment as in * 6 was performed. * 8: Pulverized walnut shell (average 800 μm). * 9: Mizukanite AP (manufactured by Mizusawa Chemical Industry Co., Ltd.). _{Composition, 5ZnO · Al 2 O 3 ·} 3SiO 2 · 5H 2 O / 4
SiO ₂ . Average particle size 3-5 μm. BET specific surface area 200
m ² / g or more. Pore 0.4 ml / g or more * 10: Based on JIS K6253.測定 Measured in an atmosphere of -5 ° C * 11: Based on JIS K6264. The value of the comparative example is 100
Expressed as an index. The larger the value, the better the abrasion resistance, and the allowable range is 95 or more. * 12: The braking distance was measured at a speed of 40 km / h on an ice surface (road temperature: -5 ° C, air temperature: -5 ° C) ( The evaluation course is on the shores of Lake Saroma in Hokkaido). The result of the comparative example is 100
Expressed as an index. The larger the value, the shorter the braking distance,
Indicates good.

[0033]

[Table 2]

[0034]

[Table 3]

Examples 11 to 13 and Comparative Examples 6 to 7 (T
B (Truck / Bus Tire) Components shown in the following [Table 4] were blended in the proportions shown in the same table. Thereafter, the mixture was kneaded using a Banbury mixer according to a general method to obtain a rubber composition.

The obtained rubber composition was vulcanized at 160 ° C. for 20 minutes, and the JIS hardness of the vulcanized product (in an atmosphere of ＠ -5 ° C.) was changed to J.
It was measured in accordance with IS K6253. The Lambourn friction of the vulcanized product was measured according to JIS K6264. Further, a TB tire (10.00R2014PR) having a tread formed from the obtained rubber composition was mounted on a heavy-duty vehicle (Isuzu Elf, manufactured by Isuzu Motor Co., Ltd.), and the braking distance on ice was measured. The results are shown in the same table.

[0037]

[Table 4] * 3: Seast 9 (manufactured by Tokai Carbon Co., Ltd.) * 1 to * 2 and * 4 to * 12: Same as in [Table 1] above.

From the above Tables 1 to 4, it is possible to obtain a tire excellent in frictional force (good in abrasion resistance) and short in braking distance by blending the flypontite-silica composite. You can see that.

[0039]

According to the present invention, it is possible to provide a rubber composition for obtaining a tire having a good contact with a road surface on snow and ice, an excellent frictional force on ice, and a short braking distance.

 ────────────────────────────────────────────────── ─── Continuing on the front page (72) Inventor Kentaro Nishioka 1-17-18 Edobori, Nishi-ku, Osaka-shi, Osaka Toyo Tire & Rubber Co., Ltd. F-term (reference) 4J002 AC011 AC031 AC061 AC081 AC121 DA036 DE188 DJ008 DJ017 FD208 GN01

Claims (4)

[Claims] 1. 100 parts by weight of a rubber component are mixed with 20 to 60 parts by weight of carbon black, 30 parts by weight or less of silica, and 40 to 60 parts by weight of a total amount of carbon black and silica, and are added according to JIS K6253. Sulphate J
A rubber composition for tires having an IS hardness (＠ -5 ° C.) of 50 to 60, further comprising a flypontite-silica composite. 2. 100 parts by weight of the rubber component is mixed with 20 to 60 parts by weight of carbon black, 30 parts by weight or less of silica, and 40 to 60 parts by weight of the total amount of carbon black and silica, and is measured according to JIS K6253. Sulphate J
A rubber composition for tires, wherein the rubber composition for tires having an IS hardness (＠ -5 ° C.) of 60 to 70 further contains a fly pontite-silica composite. 3. The rubber composition for a tire according to claim 1, wherein the compounding ratio of the frypontite-silica composite is 1 to 10 parts by weight based on 100 parts by weight of the rubber. 4. The rubber composition for a tire according to any one of claims 1 to 3, further comprising a vegetable granular material such as a crushed walnut shell.