JP2003011609A - Pneumatic tire - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a pneumatic tire having superior performances such as a braking performance and a steering stability and superior low fuel consumption performance on a wet road surface and imparting conductivity to a tire surface. SOLUTION: This pneumatic tire is formed by containing vulcanizable rubber of 100 pts.wt., and silica surface treatment carbon black of 10-200 pts.wt. for silica content of 0.1-50 wt.% as filler and also formed by disposing rubber composition, whose electric resistance of a vulcanizate is 10<6> Ωcm or less, on the surface of a tire tread with the electric resistance of 10<6> Ωcm or more or a part of its vicinity.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a pneumatic tire, and more specifically, to a wet road surface of a tire obtained by arranging a rubber composition having a low electric resistance in which a silica surface-treated carbon black is mixed in a part of a tire tread. Relates to a pneumatic tire having excellent conductivity without substantially deteriorating the performance such as braking performance and steering stability, and the low fuel consumption performance.

[0002]

2. Description of the Related Art In a rubber composition for a pneumatic tire, an insulating filler such as silica is used in order to improve performance such as braking performance on damp road surface, steering stability and fuel efficiency. . However, this compound has low conductivity, and static electricity generated in the vehicle body and tires of an automobile is less likely to be dissipated through the tire tread portion, so that there is a problem that radio noise, electric shock, sparks, and the like occur.

As a method for solving such a problem, a compound using carbon black having excellent conductivity is used for a part of the tire, conductive cement or the like is applied on the surface, or a thin conductive sheet is applied from the tread shoulder. Methods such as sandwiching inside the side have been proposed. A method using a tread containing silica-bonded carbon black has also been proposed. However, there is a problem that the conductive compound is inferior in wear resistance and uneven wear phenomenon is observed. On the other hand, the silica-bonded carbon black has conductivity similar to that of carbon black and is excellent in wet performance and rolling resistance, but there is a problem that it is still inferior as compared with the compounding of silica.

[0004]

As described above, in the conventional method, the member which imparts conductivity to the tire exhibits the same braking performance on wet road surface, steering stability, and low fuel consumption performance as the conventional silica compound. I couldn't. Therefore, it is an object of the present invention to provide a pneumatic tire which is excellent in performance such as braking performance on damp road surface, steering stability and low fuel consumption, and which has conductivity imparted to the tire surface.

[0005]

According to the present invention, 100 parts by weight of a vulcanizable rubber and, as a filler, 10 to 200 parts by weight of a silica surface-treated carbon black having a silica content of 0.1 to 50% by weight. A pneumatic tire comprising a rubber composition comprising a vulcanizate and having an electric resistance of less than 10 ⁶ Ωcm on a tire tread surface having an electric resistance of 10 ⁶ Ωcm or more or a part of the vicinity thereof. Provided.

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION According to the present invention, a rubber composition containing a specific silica surface-treated carbon black having an electric resistance of a vulcanized product of less than 10 ⁶ Ωcm is used, and a part of the tread on the tire circumference or a portion in the vicinity thereof. Pneumatic tire with excellent braking performance on wet road surfaces, steering stability, etc., and low fuel consumption performance by arranging it in the Can be obtained.

A partial sectional conceptual view of a pneumatic tire according to the present invention is shown in FIGS. FIG. 1 shows that the silica content according to the invention is 0.1-50% by weight, preferably 1.0-20.
The electric resistance is 10 ⁶ Ωcm or less, preferably 10 ^{5 in} weight%.
An example in which a vulcanizing compound 1 containing silica surface-treated carbon black (hereinafter, simply referred to as “silica surface-treated carbon black”) having an Ωcm or less is arranged in an annular shoulder portion between the tread 2 and the sidewall 3 is shown. The size of the vulcanizing compound is preferably 1 mm or more in thickness and 5 mm or more in width, more preferably 2 to 5 mm in thickness x 1 in width.
It is 0 to 50 mm. There are two sidewalls and annular shoulders symmetrically, but only one is shown in the figure. The same applies hereinafter.

2A and 2B show an example in which the vulcanizing compound 1 is arranged on the surface of the tread 2 so as to be in direct contact with the road surface. The dimensions of the vulcanizing compound 1 are preferably 1 mm or more in thickness and 5 mm or more in width, and more preferably 2 to 5 mm in thickness × 10 to 50 mm in width. 2A shows an example in which the tread portion 2 is arranged closer to the center than the groove, and FIG. 2B shows an example in which the tread portion 2 is arranged outside.

3 (a) and 3 (b) show an example in which the vulcanizing compound 1 is arranged in a portion including the groove 4 on the surface of the tread 2. In FIG. 3 (a), substantially the entire inner surface of the groove 4 is shown. FIG. 3B shows an example in which it is arranged on substantially the entire surface of the tread 2 including the inner surface of the groove 4. In addition, vulcanization compound 1
The dimension is preferably 1 mm or more in thickness and 5 mm or more in width, more preferably 2 to 5 mm in thickness × 10 to 50 mm in width.

The silica surface-treated carbon black used in the present invention is not particularly limited in its production method. For example, carbon black is first produced by an oil furnace method or the like, and then it is put into an atmosphere for producing white carbon. , Is produced by attaching silica to the surface of carbon black. As an example, JP-A-63
According to the method described in JP-A-63755, for example, carbon black is dispersed in water, the pH is adjusted to 6 or higher, preferably 10 to 11, while the temperature is kept at 70 ° C or higher, preferably 85 to 95 ° C. For example, it can be produced by hydrolyzing sodium silicate and depositing or depositing amorphous silica on the surface of carbon black particles.

The rubber component vulcanizable rubber compounded in the rubber composition according to the present invention is used singly or as a mixture of two or more kinds. As the vulcanizable rubber, any rubber conventionally used for tires can be used. Specifically, natural rubber (NR), various butadiene rubbers (B
R), various styrene-butadiene copolymer rubbers (SB
R), polyisoprene rubber (IR), butyl rubber (II
R), acrylonitrile-butadiene rubber, chloroprene rubber, ethylene-propylene copolymer rubber, ethylene-
Propylene-diene copolymer rubber, styrene-isoprene copolymer rubber, styrene-isoprene-butadiene copolymer rubber, isoprene-butadiene copolymer rubber, chlorosulfonated polyethylene, acrylic rubber, epichlorohydrin rubber, polysulfide rubber, silicone Rubber, fluororubber, urethane rubber or the like can be used. When used by blending, the blending ratio is not particularly limited.

According to the present invention, 10 to 20 parts of silica surface-treated carbon black is added to 100 parts by weight of the rubber component.
0 parts by weight, preferably 15 to 150 parts by weight are blended. If the blending amount is too small, the desired effect cannot be obtained, and conversely if the blending amount is too large, the hardness becomes too high or the workability deteriorates.
It is not preferable because it may be impractical as a rubber material.

The rubber composition according to the present invention may contain, for example, various resins, waxes, softening agents, antiaging agents and the like in addition to the rubber and the silica surface-treated carbon black.

The rubber composition according to the present invention is required to have an electric resistance value after vulcanization lower than 10 ⁶ Ωcm, preferably 10 ⁵ Ωcm or less. If this value is too large, it becomes difficult to obtain the above-described effect of the present invention. On the other hand, the vulcanized product of the rubber composition according to the present invention (that is, the vulcanized compound)
The tread portion for arranging can have any conventional composition, and in consideration of abrasion resistance and gripping force, it is preferable to use a blend of carbon black and silica as the filler.

The pneumatic tire according to the present invention is generally conventional except that a vulcanizing compound containing silica surface-treated carbon black is placed on or near the tread surface as shown in FIGS. Can be manufactured by a method.

[0016]

EXAMPLES The present invention will be further described below with reference to examples, but it goes without saying that the scope of the present invention is not limited to these examples.

Example 1 Preparation of Rubber Compound A silica surface-treated carbon black compound I and a conventional silica / carbon black compound II having the following composition (parts by weight) were compounded according to a conventional method.

Silica surface treated carbon black compound I SBR (NS116, Nippon Zeon) 70 SBR (Nipol 1502, Nippon Zeon) 30 Silica surface treated carbon ^{* 1} 55 Stearic acid 2 Zinc oxide 3 Anti-aging agent ^{* 2} 3 Wax ^{* 3} 1.5 Sulfur yellow 2 Vulcanization accelerator ^{* 4} 2 Aromatic oil ^{* 5} 5

Silica / carbon black compound II SBR (VSL 5025, Bayer AG) 100 BR (CB25, Bayer AG) 30 carbon (N234) ^{* 6} 40 silica ^{* 7} 40 stearic acid 2 zinc oxide 3 anti-aging agent ^{* 2} 3 Wax ^{* 3} 1.5 Sulfur yellow 2 Vulcanization accelerator ^{* 4} 2 Aromatic oil ^{* 5} 8

Blending table footnote * 1: Prepare a carbon black slurry according to a conventional method,
After heating to 90 ° C, diluted JIS No. 3 sodium silicate was added over 4 hours with a metering pump to pH 5-10.
Silica was deposited on the surface of the carbon black while maintaining it with dilute sulfuric acid and an aqueous solution of sodium hydroxide. Then pH
No. 6 and allowed to stand for 6 hours, filtered, washed with water and dried to obtain the desired product. The silica content was 5.0% by weight.

* 2: Anti-aging agent S-13 manufactured by Sumitomo Chemical * 3: Wax made by Nippon Seiro * 4: Flexis vulcanization accelerator CBS * 5: Made by Showa Shell Sekiyu * 6: Made by Tokai Carbon

In the above Formulations I and II, each component except sulfur and vulcanization accelerator was kneaded in a 1.8 L Banbury mixer for 3 to 5 minutes and discharged when a temperature of 160 ± 5 ° C. was reached. Sulfur and a vulcanization accelerator were kneaded with the obtained masterbatch with an 8-inch open roll to obtain a rubber composition.

The obtained rubber composition was treated with 15 × 15 × 0.2
A test piece was obtained by press vulcanization at 160 ° C. for 20 minutes in a metal mold of cm, and its electrical resistance was measured (according to JIS K6911). The results were as follows. Compound I: 8.8 × 10 ⁴ Ωcm Compound II: 2.8 × 10 ⁷ Ωcm

About the tire (size: 195 / 65R15) in which the color of Compound II obtained in Example 2 is arranged as shown in FIGS. 1 to 3, braking performance and steering stability on wet roads, fuel economy and conductivity are obtained. The sex was evaluated by the following method. The results are shown in Table I.

Evaluation method Braking performance: The initial braking speed of 100 km / h is stabilized, and the four-wheel ABS braking is maintained from the braking start point to the stop. The braking performance was judged by the distance to the stop. Steering stability: Stability and response to disturbance when the vehicle travels straight ahead, responsiveness when changing lane, response and grip are evaluated. Fuel cost: Evaluated by the force (rolling resistance) generated in the direction opposite to the traveling direction when the tire was run on the drum. Conductivity: According to JATMA, the internal pressure was 200 kPa, the load pressure was 4.82 KN, and the measurement voltage was 250 V.

[0026]

[Table 1]

[0027]

As described above, according to the present invention, the conductivity can be imparted without substantially lowering the physical properties as compared with the conventional method of imparting the conductivity to the tire surface by preventing static electricity. It is possible to obtain a pneumatic tire having no difference in wet performance, wear resistance and low rolling property of the tire tread portion, no change in effect over time, and having workability similar to that of the tread compound.

[Brief description of drawings]

FIG. 1 is a partial cross-sectional conceptual diagram of an example of a pneumatic tire according to the present invention.

FIG. 2 is a partial cross-sectional conceptual view of another example of the pneumatic tire according to the present invention, in which FIG. 2 (a) is closer to the tire center side than the groove of the tread portion, and FIG. 2 (b) is the tread portion. An example is shown in which vulcanizing compounds are arranged outside the grooves.

FIG. 3 is a partial cross-sectional conceptual view of still another example of the pneumatic tire according to the present invention, in which FIG.
(B) shows an example in which a vulcanizing compound is arranged on each of the tread surfaces including the inner surface of the groove.

[Explanation of symbols]

1 ... Vulcanization compound 2 ... Tread part 3 ... Sidewall part 4 ... groove

Continued front page    F-term (reference) 4J002 AC011 AC021 AC031 AC061                       AC071 AC081 AC091 BB151                       BB181 BB271 BD121 BG041                       CH041 CK021 CN021 CP031                       DA036 FB076 FD016 GN01

Claims (4)

[Claims] 1. A vulcanized product comprising 100 parts by weight of vulcanizable rubber and 10 to 200 parts by weight of silica surface-treated carbon black having a silica content of 0.1 to 50% by weight as a filler. a pneumatic tire electric resistance lower rubber composition than 10 ⁶ [Omega] cm, formed by arrangement of a part of the electric resistance 10 ⁶ [Omega] cm or more tire tread or near the surface of the. 2. The rubber composition having a thickness of 1 mm or more and a width of 5 mm or more is directly applied to the two annular shoulder portions between the tread on the tire tread surface and the two sidewalls. The pneumatic tire according to claim 1, wherein the pneumatic tire is arranged so as to come into contact with a road surface. 3. A tire tread surface having an electric resistance of 10 ⁶ Ωcm or more, having a thickness of 5 mm or more and a width of 5 mm or more, and having an electric resistance of the vulcanized product lower than 10 ⁶ Ωcm, and directly contacting the road surface during running. As described above, the pneumatic tire according to claim 1, wherein the rubber composition is arranged on the circumference of the tire. 4. The pneumatic tire according to claim 1, wherein the rubber composition is arranged on a portion of the tread surface including a groove with a thickness of 1 mm or more and a width of 5 mm or more on the circumference of the tire.