JP2003191711A - Tire and its manufacturing method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a tire and its manufacturing method which realizes both durability and inner pressure holding performance at run-flat. <P>SOLUTION: This tire provided with an inner liner is characterized in that a rubber component of an inner liner includes at least 10% by mass or more at a portion corresponding to a tire side part and a ratio of diene rubber is smaller at a portion corresponding to a tire tread part than the portion corresponding to the side. This is the manufacturing method of the timer with the inner liner characterized in that when a rubber composition is taken out from each of a plurality of tanks with various rubber components, extruded by a extruding machine, and then, the extruded composition is wound on a rotating support body so as to form an inner liner layer of the tire, the taken-out amount of the rubber composition is changed so that the rubber component of the inner liner has the above characteristics. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a tire, and more particularly, to a run flat tire that can travel safely even when the air pressure of the tire decreases.

[0002]

2. Description of the Related Art Generally, a composite having various rubbers requires a step of laminating various unvulcanized rubber members before vulcanization of the composite during manufacturing. When the composite is a pneumatic tire, the tire is composed of a reinforcing member made of organic fiber or steel cord and various rubber members. Therefore, before the tire is vulcanized, an unvulcanized tire in which an unvulcanized rubber member and a reinforcing member such as a cord are bonded together is prepared in a molding process.

However, today, the performance requirements for rubber composites including tires are becoming more sophisticated and diversifying. Therefore, the molding process is inevitably complicated and still requires manual work. However, if a manual process is performed in the molding process, the molding efficiency cannot be significantly improved, and the bonding accuracy of various members is deteriorated. In particular, in the case of a tire, the quality of the sticking influences the quality of the tire, and therefore it is strongly desired to improve the sticking accuracy as well as the molding efficiency.

Therefore, in order to meet these demands, in Japanese Patent Publication No. 7-94155, an outlet orifice of a constant volume extruder is positioned near a position where a rubber member is arranged on a rotating support, and a constant volume extruder is provided. It proposes a method and apparatus for directly extruding a rubber composition onto a support from an extruder via an exit orifice. Further, Japanese Patent Laid-Open No. 2000-79643 proposes a method and an apparatus for directly extruding a plurality of rubber compositions onto a support while mixing them with one extruder.

On the other hand, there is a demand for a run-flat tire that can run even if the internal pressure drops due to foreign matter such as nails or for some other reason, with tire safety being important. Or Japanese Patent Laid-Open No. 4-185512
As described above, a type using a side reinforcing rubber has been proposed.

One of the drawbacks of the side-reinforcement type run flat tire is that the bending of the side portion during running of the tire when the internal pressure is lowered becomes considerably larger than that when there is internal pressure, so that rubber separation occurs between rubbers. Occurs. The reason is that the inner liner is composed only of butyl rubber or halogenated butyl rubber, and the side reinforcing rubber contains diene rubber as the main component, so the adhesive force between the two is not sufficient. When the rubber is peeled off, even the side-reinforcing rubber may be destroyed and the vehicle may not run.

When the inner liner is made of a diene rubber in order to prevent the rubber from peeling off, the diene rubber has a low air permeation preventive ability, so that the air impermeability which is the original role of the inner liner is lowered. Undesirable problems arise.

Further, when the side reinforcing rubber is made of butyl rubber, not only peeling between the carcass ply and the side reinforcing rubber occurs, but also the butyl rubber has a large heat generation property, which causes a problem in durability.

On the other hand, when natural rubber is used in combination with the inner liner containing butyl rubber or halogenated butyl rubber as a main component, the adhesive force with other members made of diene rubber is improved, but in the conventional drum molding, the inner liner is a single piece. Since it is formed of a sheet-shaped rubber of one composition, there is a problem that the retention of internal pressure is greatly reduced due to the presence of natural rubber having a low air permeation preventing ability.

[0010]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems of the prior art and to provide a tire having both durability during run-flat and internal pressure retention, and a method for producing the tire.

[0011]

Means for solving the above-mentioned problems are as follows. That is, (1) the rubber component of the inner liner contains at least 10% by mass or more of a diene rubber in the portion corresponding to the tire side portion, and the portion corresponding to the tire tread portion has a diene rubber ratio higher than that of the side corresponding portion. A tire with an inner liner characterized by being low. (2) The tire according to (1), wherein the rubber component of the inner liner contains 10 to 40 mass% of a diene rubber in a portion corresponding to a tire side portion. (3) The rubber component of the inner liner contains halogenated butyl rubber as a main component and halogenated butyl rubber 90 to
The tire according to (1) or (2) above, which contains 60% by mass and 10 to 40% by mass of a diene rubber.

(4) The tire according to any one of (1) to (3), wherein the diene rubber is natural rubber. (5) The tire according to any one of (1) to (4), characterized in that a reinforcing rubber having a substantially crescent-shaped cross section is provided between the inner liner of the tire side portion and the carcass ply. . (6) The above-mentioned (1) or (2), wherein the ratio of the diene rubber in the rubber component of the inner liner is continuously changed between the tire side equivalent part and the tire tread equivalent part. Tires.

(7) The rubber composition is taken out from each of a plurality of storage tanks containing different kinds of rubber compositions, extruded by an extruder while kneading these, and then the extruded product is wound on a rotating support. When forming the inner liner layer of the tire by turning, the rubber component of the inner liner contains at least 10% by mass of diene rubber in the portion corresponding to the tire side portion, and the side portion in the portion corresponding to the tire tread portion. A method for producing a tire having an inner liner, characterized in that the amount of the rubber composition taken out is changed so that the ratio of the diene rubber is lower than that of a corresponding portion. (8) The method for manufacturing a tire according to (7), characterized in that the taken-out amount is continuously changed. (9) In the tire manufacturing method according to (7) or (8), the rotating support is a rigid core having an outer surface shape substantially corresponding to an inner surface shape of the product tire.

[0014]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below. In the tire provided with the inner liner of the present invention, the rubber component of the inner liner contains at least 10% by mass or more of the diene rubber in the portion corresponding to the tire side portion, preferably 10 to 40% by mass, more preferably 10% by mass.
Includes ~ 35 mass% diene rubber. Therefore, the inner liner of the present invention has a higher adhesive force with the side portion containing a diene rubber as a main component than a conventional inner liner in which the rubber component is only butyl rubber or halogenated butyl rubber. In addition, in the tire of the present invention, the gas filled in the tire may be air or an inert gas such as nitrogen.

On the other hand, the rubber component of the inner liner has a diene rubber ratio lower in the portion corresponding to the tire tread portion than in the portion corresponding to the side. Since the part corresponding to the tread does not bend much during run-flat running, by applying a rubber component with a lower diene rubber ratio (rubber component with a higher butyl rubber or halogenated butyl rubber ratio) than the side equivalent part It is possible to enhance the internal pressure retention, which is the role of.

Compared to the case where a rubber component having the same diene-based rubber ratio is used in the tread-corresponding part and the side-corresponding part in order to improve the run-flat durability, the inner liner of the present invention has a diene-based rubber ratio in the tread-corresponding part. Is lower than the proportion of the diene rubber in the portion corresponding to the side, the degree of decrease in the internal pressure retention is small because the proportion of the diene rubber in the portion corresponding to the tread is low.

The tire inner liner of the present invention contains halogenated butyl rubber as a main component, and contains 90 to 60% by mass of halogenated butyl rubber and diene from the viewpoint of achieving both durability during run-flat and internal pressure retention. It is preferable to contain 10 to 40% by mass of the system rubber.

The diene rubber used in the present invention includes
Natural rubber, synthetic diene rubber and the like can be mentioned. Among them, natural rubber is preferable, and halogenated butyl rubber can be brominated butyl rubber and the like. In the present invention, in addition to the above-mentioned diene rubber and halogenated butyl rubber, compounding agents or the like usually used in the innerliner composition in the tire industry can be added.

The tire of the present invention is preferably a run flat tire. Here, the run-flat tire of the present invention is characterized in that a reinforcing rubber having a substantially crescent-shaped cross section is provided between the inner liner and the ply of the tire side portion.

In the inner liner of the tire of the present invention, it is preferable to continuously change the ratio of the diene rubber in the rubber component of the inner liner between the tire side corresponding portion and the tire tread corresponding portion. The thickness of the liner may be continuously changed from the tire side corresponding portion to the tire tread corresponding portion. The inner liner has a high ratio of butyl rubber or halogenated butyl rubber, and the thicker it is, the better the internal pressure retention becomes, but it is disadvantageous in terms of cost.Therefore, the rubber component / thickness of the inner liner should be continuous in the tire width direction. By changing to, it becomes possible to optimally arrange the rubber component in terms of performance / cost.

In order to make the inner liner as described above, it is possible to use a divided body made of a rubber component compounded body corresponding to the side portion and the tread portion in pasting the inner liner in conventional drum molding. However, as has been pointed out in the past, drum molding requires a manual operation, cannot significantly improve the molding efficiency, and has a problem in that the sticking accuracy is reduced. In contrast,
If the manufacturing method of the present invention is adopted, the problem of the drum molding can be solved.

In the present invention, the rubber composition is taken out from each of a plurality of storage tanks containing two or more kinds of different rubber compositions, and then these rubber compositions are extruded by an extruder while kneading and then extruded. In forming the inner liner layer of the tire by winding the object on a rotating support, the rubber component of the inner liner contains at least 10% by mass or more of a diene rubber in the portion corresponding to the tire side portion, In the portion corresponding to the tread portion, the amount of the rubber composition taken out is changed so that the proportion of the diene rubber in the portion corresponding to the side becomes lower.

Here, the ratio of the diene rubber in the same inner liner can be continuously changed by continuously changing the amount of different rubber compositions taken out from a plurality of storage tanks. The ratio of the diene rubber in the rubber component of the inner liner can be continuously changed between the tire side equivalent portion and the tire tread equivalent portion.

If the manufacturing method of the present invention is adopted, it becomes easy to arbitrarily change the diene rubber ratio between the side equivalent part and the tread equivalent part of the inner liner, and no manual work is required, so that productivity is improved. Can be raised. Further, according to the manufacturing method of the present invention, the thickness can be easily changed arbitrarily.

An embodiment of the present invention will be described in detail below with reference to FIG. FIG. 1 is a schematic side view of a manufacturing apparatus that realizes the tire manufacturing method of the present invention.

In FIG. 1, the support 1 is attached to a shaft 1a which is rotated by the drive of a rotary drive source (not shown).
The support 1 is a green tire molding rigid core. The raw tire molding rigid core has an outer surface shape substantially corresponding to the inner surface shape of the product tire. The support 1 has a winding surface of a rubber member on its surface.

The extruder 2 is arranged so that the rubber member supply portion 2a of the extruder 2 is located near the surface of the support 1.
The manufacturing apparatus shown in FIG. 1 is a combined apparatus of the support 1 and the extruder 2. The supply unit 2a includes both a case where a normal extrusion die is provided and a case where a pair of upper and lower roller dies are provided instead of the extrusion die. Examples of the shape of the rubber member extruded from the supply unit 2a include a ribbon shape and a string shape.

The extruder 2 has storage tanks 3a, 3 for individually storing two or more kinds, and in the illustrated example, two kinds of unvulcanized rubber compositions A and B.
b. Further, the rubber composition storage tanks 3a and 3b are provided with a rubber composition supply device 4 for individually adjusting the supply amounts of the rubber compositions A and B, respectively. The rubber compositions A and B that have passed through the rubber composition supply device 4 are charged into the main body of the extruder 2 via a hopper or a feeder 5.

In the present invention, the rubber composition storage tanks 3a and 3b are used.
A rubber composition in which the ratio of the diene rubber to the halogenated butyl rubber is different, for example, the rubber component is halogenated butyl rubber
100% by mass of the rubber composition A and a rubber composition B containing 75% by mass of halogenated butyl rubber and 25% by mass of a diene rubber as rubber components were respectively charged, and depending on the portion of the inner liner to be manufactured, The rubber composition supply device 4 controls the supply amount of each rubber composition. Although the extruder in the illustrated example includes two storage tanks, the number of storage tanks is not limited to this, and if the extruder has two or more storage tanks, the object of the present invention can be achieved. obtain.

The extruder 2 is also equipped with a rubber composition supply device 4
Through the above, according to the portion of the inner liner to be replaced or manufactured, there is provided a control means for controlling the charging timing and charging stopping timing of each rubber composition and the outflow amount. Thereby, for example, the rubber composition used in the tread-corresponding portion and the side-corresponding portion of the inner liner can be changed,
Further, by continuously changing the amount of each rubber composition taken out during the formation of one inner liner, it is possible to continuously change the ratio of the diene rubber between the tire side equivalent portion and the tread equivalent portion. it can.

Further, the extruder 2 is provided with a linear moving mechanism 6. The linear movement mechanism 6 linearly moves the extruder 2 along the central axis X of the rotation shaft 1a of the support 1. This move is
The rubber member supplied from the supply unit 2a is wound around the winding surface of the support 1 in a spiral manner. Further, instead of the linear movement mechanism 6, the support 1 may include a linear movement mechanism (not shown).

Further, when the winding surface of the support 1 is a curved surface having a large curvature, the extruder 2 has the linear moving mechanism 6
In addition, a turning movement mechanism (not shown) is provided. The turning movement mechanism turns the tip of the supply unit 2 a along the winding curved surface of the support 1.

Further, the manufacturing apparatus shown in FIG. 1 has a guide roller 7 in front of the supply section 2a of the extruder 2. The guide roller 7 guides the rubber member supplied from the supply unit 2a to a predetermined position on the winding surface of the rotating support 1.

[0034]

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

Comparative Examples 1 and 2 and Examples 1 to 3 Rubber compositions A to D having the formulations shown in Table 1 were prepared, respectively, and Table 2
The inner liner of the part corresponding to the tread part or the side part of the tire is manufactured with the combination of PSR 245/40 Z
A side-reinforced run-flat tire having a tire size of R18 was manufactured. The inner liners shown in Comparative Examples 1 and 2 were produced by conventional drum molding using the rubber composition A or C, and the inner liners shown in Examples 1 to 3 were produced by the apparatus shown in FIG. It was done. The run flat durability and air retention of these tires were measured by the methods described below, and the results shown in Table 2 were obtained.

The run-flat durability was evaluated by running each test tire under the conditions of a load of 6.23 KN and an internal pressure of 0 KPa at a speed of 90 Km / hr and measuring the running distance until a tire failure occurred. Then, the mileage of Comparative Example 1 is set to 100 and displayed as an index. The larger the index value, the better the run flat durability.

The air retention property was evaluated by measuring the tire internal pressure after allowing the test tire filled with the internal pressure of 230 KPa to stand at a test room temperature of 25 ± 2 ° C. for 30 days. The retention rate is set to 100 and displayed as an index. The larger the index value, the better the air retention.

[0038]

[Table 1]

[0039]

[Table 2]

Comparative Example 2 is a mixture of a brominated butyl rubber and a diene rubber in order to improve the run flat durability of Comparative Example 1 corresponding to the conventional inner liner. By mixing the diene rubber, the run flat durability is improved, but the air retention property is greatly reduced.

Example 1 is an example in which the diene rubber is mixed only in the side corresponding portion in comparison with Comparative Example 1, and the run-flat durability is improved by mixing the diene rubber in the side corresponding portion, and the tread equivalent is obtained. The rubber component of the part was composed of only brominated butyl rubber as in Comparative Example 1, so that the air retention could be slightly reduced.

Example 2 is an example in which the proportion of the diene rubber in the side equivalent portion and the tread equivalent portion is further increased as compared with Example 1, and although the air retention property is the same as that of Comparative Example 2, the run flat durability is obtained. The property was further improved as compared with Comparative Example 2 and Example 1.

In Example 3, the gauge of the side-corresponding part is 1.3 times that of Example 2, and the run-flat durability is very excellent as in Example 2, while the side-corresponding part is very good. By increasing the thickness, the air retention was improved, and the decrease in the air retention seen from Comparative Example 1 could be made slight.

[0044]

The rubber component of the inner liner contains at least 10% by mass of diene rubber in the portion corresponding to the tire side portion, and the portion corresponding to the tire tread portion has a diene rubber ratio higher than that of the side corresponding portion. By applying an inner liner that is characterized by being low to the tire, run flat durability is reduced while suppressing deterioration of air retention compared to a tire equipped with an inner liner made of only conventional butyl rubber or halogenated butyl rubber. It has improved significantly.

In the production of such a tire, the rubber composition is taken out from each of a plurality of storage tanks containing different kinds of rubber compositions, extruded by an extruder while kneading these, and then the extrudate is rotated. When forming the inner liner layer of the tire by winding on the support, the rubber component of the inner liner contains at least 10% by mass of diene rubber in the portion corresponding to the tire side portion and corresponds to the tire tread portion. By changing the amount of the rubber composition taken out so that the proportion of the diene rubber in the portion corresponding to the side is lower than that in the portion corresponding to the side, the side of the inner liner can be obtained by adopting the tire manufacturing method of the present invention. It is easy to arbitrarily change the diene rubber ratio between the equivalent part and the tread equivalent part, and productivity is improved because no manual work is required. And can also.

[Brief description of drawings]

FIG. 1 is a schematic side view of a tire manufacturing apparatus used in a manufacturing method of the present invention.

[Explanation of symbols]

1 support 1a rotating shaft 2 extruder 2a Supply section 3a, 3b Rubber storage tank 4 Rubber composition feeder 5 hopper (feeder) 6 Linear movement mechanism 7 Guide roller X center axis

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Claims (9)

[Claims] 1. The rubber component of the inner liner contains at least 10% by mass or more of diene rubber in the portion corresponding to the tire side portion, and in the portion corresponding to the tire tread portion, the diene rubber ratio is higher than that in the side corresponding portion. A tire with an inner liner characterized by lowness. 2. The tire according to claim 1, wherein the rubber component of the inner liner contains 10 to 40% by mass of a diene rubber in a portion corresponding to a tire side portion. 3. The rubber component of the inner liner is mainly composed of halogenated butyl rubber, and contains 90 to 60 mass% of halogenated butyl rubber and 10 to 40 mass% of diene rubber. Or the tire according to 2. 4. The tire according to claim 1, wherein the diene rubber is natural rubber. 5. The tire according to any one of claims 1 to 4, wherein a reinforcing rubber having a substantially crescent-shaped cross section is provided between the inner liner of the tire side portion and the carcass ply. 6. The tire according to claim 1, wherein the ratio of the diene rubber in the rubber component of the inner liner is continuously changed between the tire side equivalent portion and the tire tread equivalent portion. . 7. A rubber composition is taken out from each of a plurality of storage tanks containing different kinds of rubber compositions, extruded by an extruder while kneading these, and then the extruded product is wound on a rotating support. In forming the inner liner layer of the tire, the rubber component of the inner liner contains at least 10% by mass of diene rubber in the portion corresponding to the tire side portion, and the side corresponding to the tire tread portion. A method for producing a tire having an inner liner, characterized in that the amount of the rubber composition taken out is changed so that the ratio of the diene rubber is lower than that of the portion. 8. The method for manufacturing a tire according to claim 7, wherein the taken-out amount is continuously changed. 9. The tire manufacturing method according to claim 7, wherein the rotating support is a rigid core having an outer surface shape substantially corresponding to an inner surface shape of the product tire.