JP2005255051A - Manufacturing method for pneumatic tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pneumatic tire capable of exerting excellent braking driving characteristic even if the tire temperature has risen in the high-speed running such as sports running while the tread rubber has a high silica content. <P>SOLUTION: The tread 1 of the pneumatic tire is formed from a rubber compound having a high silica content, and at the surface of the tread 1, band-shaped rubber layers 2 formed from a rubber compound of a high carbon black content and having a modulus at 100°C and 100-% elongation of 3-10 MPa are arranged in rows intermittently in the tire circumferential direction in such a way as straddling over the left and right shoulder ends. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pneumatic tire. More specifically, the present invention relates to a pneumatic tire that exhibits excellent braking / driving performance even when the tire temperature rises during high-speed running such as sports running while providing a tread rubber with high silica content. About.

  In recent years, tires that reduce the rolling resistance by reducing the amount of carbon black in the tread rubber and replacing it with a large amount of silica and improve the braking / driving performance on wet road surfaces are used. (Patent Document 1, etc.).

However, silica has lower reinforcement at high temperatures than carbon black, so it reduces rolling resistance and improves braking / driving performance on wet roads, as described above, but tire speeds when running at high speeds such as sports As a result, the tread rigidity is lowered and the braking / driving performance is lowered. However, there has not yet been proposed an improvement measure that can be satisfactorily satisfied with respect to a measure for braking / driving that decreases during high-speed running such as sports running.
JP 9-71112 A

  The object of the present invention is to solve the above-mentioned problems and provide excellent braking / driving performance even if the tire temperature rises during high-speed running such as sports running while providing a tread rubber with high silica content. The purpose is to provide tires.

  The pneumatic tire of the present invention that achieves the above object comprises a tread composed of a rubber composition that is highly compounded with silica, a high compound of carbon black on the surface of the tread, and a modulus at 100% elongation at 100 ° C. A belt-like rubber layer made of a rubber composition having a thickness of 3 to 10 MPa straddles between the left and right shoulder ends and is intermittently arranged in the tire circumferential direction.

  According to the present invention, from a high modulus rubber composition in which carbon black is highly compounded and a modulus at 100% elongation at 100 ° C. is 3 to 10 MPa with respect to a tread composed of a rubber composition with high silica content. The belt-like rubber layer is placed so as to straddle between the left and right shoulder ends, and intermittently arranged in the tire circumferential direction. Even when the rigidity is lowered, excellent braking / driving performance can be exhibited by maintaining high rigidity in the tire circumferential direction by the high modulus belt-like rubber layer.

  FIG. 1 shows an example in which a main part of a pneumatic tire of the present invention is broken.

  1 is a tread, 3 is a bead portion, 4 is a sidewall portion, and 7 is a carcass layer. A belt layer 5 is provided inside the tread 1, and a plurality of main grooves 6 are provided on the surface so as to extend in the tire circumferential direction. The tread 1 has a wing made of a rubber composition with a high carbon black content on both sides of a laminate of a cap tread rubber 11 made of a rubber composition with a high silica content and an under tread rubber 12 made of a rubber composition with a high carbon black content. A chip rubber 13 is arranged.

  On the surface of the tread 1, a belt-like rubber layer 2 made of a rubber composition that is highly compounded with carbon black and has a modulus of 3 to 10 MPa at 100% elongation at 100 ° C. crosses the plurality of main grooves 6. And is provided so as to straddle between the left and right shoulder ends. A plurality of belt-like rubber layers 2 are arranged intermittently at a predetermined pitch in the tire circumferential direction.

  The belt-like rubber layer 2 is preferably in contact with the undertread rubber 12 at the groove bottom crossing the main groove 6, but is not necessarily in contact, and the separation distance from the undertread rubber 12 is 0. It may be separated as long as it is 8 mm or less. If the distance is longer than 0.8 mm, the belt-like rubber layer 2 becomes easy to move independently of the undertread rubber 12, and the reinforcing action of the belt-like rubber layer 2 is lowered.

  In the pneumatic tire of the present invention, as described above, carbon black is highly blended, and the high modulus belt-like rubber layer 2 straddles between the shoulder ends on the surface of the tread 1 and is intermittent in the tire circumferential direction. Even when the tire temperature rises as the rigidity of the cap tread rubber 11 of the tread 1 decreases when performing high speed running such as sports running, the belt-like rubber layer 2 is in the tire circumferential direction. By maintaining the rigidity, excellent braking / driving performance can be exhibited.

  In the present invention, the tread pattern is not particularly limited, and may be a rib pattern in which a main groove in the tire circumferential direction extends or a block pattern as in the illustrated example, or a rib and a block. Any of the patterns in which both are mixed may be used.

  The rubber composition with high silica content that constitutes the tread does not need to constitute the entire tread, and may suffice if it occupies at least the main part on the cap side. That is, the main body is composed of a laminate of upper and lower layers of a cap tread rubber made of a silica composition with a high silica content and an under tread rubber made of a rubber composition with a high composition of carbon black. The main body may be constituted only by a single rubber layer made of a rubber composition with a high silica content.

  Thus, the tread composed of the rubber composition containing high silica can reduce the rolling resistance of the tire and can improve the braking / driving performance on the wet road surface. Moreover, as such a rubber composition, at least 40 parts by weight of silica is 100 parts by weight of rubber. Preferably, 45 to 100 parts by weight and 30 parts by weight or less of carbon black are blended. If the amount of silica is less than 40 parts by weight, the effect of reducing rolling resistance and the effect of improving braking / driving on wet road surfaces become insufficient. On the other hand, when the amount is more than 100 parts by weight, the processability is poor, so it is not practical.

  The belt-like rubber layer provided on the tread surface is required to be a rubber composition containing high carbon black and having a modulus of 3 to 10 MPa at 100% elongation at 100 ° C. Since this rubber composition has a higher reinforcing property than that of silica at high temperatures, the rubber composition does not easily deform while maintaining high rigidity even at high temperatures. Further, since the belt-like rubber layer is arranged so as to cross the tread in the tire width direction, it is possible to exhibit higher rigidity in the tire circumferential direction. If the modulus at 100% elongation is less than 3 MPa, it becomes difficult to ensure braking / driving performance during high speed running such as sports running. On the other hand, if the pressure is higher than 10 MPa, the difference in rigidity from the surrounding tread rubber becomes too large, which tends to cause abnormal wear.

  In order to obtain the high modulus as described above, the composition of the rubber composition used for the belt-shaped rubber layer is 35 to 100 parts by weight, more preferably 40 to 100 parts by weight of carbon black with respect to 100 parts by weight of rubber. What was blended is good. If the blending amount of carbon black is less than 35 parts by weight, it is difficult to maintain rigidity at high temperatures. On the other hand, if the amount exceeds 100 parts by weight, the processability is poor and it becomes impractical.

  The thickness of the belt-like rubber layer is not particularly limited, but is preferably in the range of 0.5 to 3 mm, and more preferably in the range of 1 to 2.5 mm. If it is thinner than 0.5 mm, the reinforcing effect is small, and if it is larger than 3 mm, molding becomes difficult.

  As the size of each belt-shaped rubber layer, the width in the tire circumferential direction is preferably 5 to 20 mm. When the width in the tire circumferential direction is narrower than 5 mm, the braking / driving effect at the time of high-speed high-temperature running is reduced. On the other hand, when the width is larger than 20 mm, the rolling resistance reduction effect during normal running and the braking performance on wet road surfaces are reduced by the tread having a high silica content.

  Moreover, as a pitch which this belt-shaped rubber layer arranges in a tire peripheral direction, it is good to set it as 50-100 mm. If it is less than 50 mm, the rolling resistance is reduced and the braking effect on a wet road surface is reduced. On the other hand, if it is larger than 100 mm, the braking / driving performance at the time of high speed running such as sports running is lowered.

  The tire size is 215 / 60R16, the tire structure is shown in FIG. 1, a cap tread rubber in a tread is made into a rubber composition containing 100 parts by weight of silica, 60 parts by weight of silica and 20 parts by weight of carbon black, and the under tread rubber is made of rubber 100. A rubber composition in which 60 parts by weight of carbon black is blended in parts by weight, the thickness of the belt-like rubber layer is 2 mm, the distance from the under tread is 0.5 mm, the width in the tire circumferential direction is 10 mm, and the arrangement pitch is 80 mm This is a pneumatic tire in which the rubber composition of the belt-shaped rubber layer (the blending amount of carbon black with respect to 100 parts by weight of rubber) and the modulus at 100% elongation at 100 ° C. are made different as shown in Table 1. Examples 1, 2, 3 and Comparative Example 1) were produced.

  In addition, a pneumatic tire (Comparative Example 2) having the same conditions as in Example 1 except that no belt-like rubber layer was provided in the tire of Example 1 was manufactured.

  For the above four types of tires, the braking / driving performance during sports running was examined by the following test method, and the results shown in Table 1 were obtained.

[Driving control]
A test tire is mounted on a standard rim and filled with air pressure of 200 kPa. This test tire is mounted on a one-box car with a displacement of 3000 cc. The braking distance when sudden braking was applied from 60 km / h was measured.

  The evaluation was expressed as an index with the braking distance of the tire of Comparative Example 1 as 100. The smaller the index value, the better the braking / driving performance.

It is the perspective view which fractured | ruptured the principal part and illustrated the pneumatic tire of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Tread 2 Band-shaped rubber layer 3 Bead part 4 Side wall part 5 Belt layer 11 Cap tread rubber 12 Under tread rubber 13 Wing chip rubber

Claims (4)

  A rubber band comprising a rubber composition comprising a rubber composition with a high silica content, a carbon composition having a high carbon black content on the surface of the tread, and a modulus of 3 to 10 MPa at 100% elongation at 100 ° C. A pneumatic tire having a layer straddling between left and right shoulder ends and intermittently arranged in the tire circumferential direction.   The rubber composition in which the silica is highly blended is a rubber composition in which at least 40 parts by weight of silica and 30 parts by weight or less of carbon black are blended with respect to 100 parts by weight of rubber, and the rubber composition constituting the belt-shaped rubber layer The pneumatic tire according to claim 1, wherein the product is a rubber composition in which 35 to 100 parts by weight of carbon black is blended with 100 parts by weight of rubber.   The pneumatic tire according to claim 1 or 2, wherein the width of the belt-shaped rubber layer in the tire circumferential direction is 5 to 20 mm, and the arrangement pitch with respect to the tire circumferential direction is 50 to 100 mm. The tread is composed of a laminated body of a cap tread of a rubber composition highly blended with silica and an under tread of a rubber composition highly blended with carbon black, and a main groove extending in the tire circumferential direction is provided on the surface of the tread, 4. The groove bottom at which the belt-like rubber layer crosses the main groove, the belt-like rubber layer is spaced apart from or brought into contact with the under tread within a distance of 0.8 mm. The described pneumatic tire.

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