JP2003285376A - Method for manufacturing self-sealing tire - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for manufacturing a self-sealing tire with excellent productivity in which sealing properties are ensured over the whole tread face of a tire and uniformity of the tire is kept by preventing a sealant substance from flowing. <P>SOLUTION: In the method for manufacturing the self-sealing tire in which a sealant layer 9 prepared by decomposing a rubber ingredient with a peroxide is arranged on the inside of a crown part 1, a cover rubber layer 10 is wound on the outer peripheral side of a molding drum 11, and a sheet material 9A of a rubber composition comprising the sealant layer 9 and a partition material 8 for dividing the sealant layer 9 into a plurality of regions are wound on the outer peripheral side of the cover rubber layer 10. Furthermore, a tire constitutional member such as an inner liner layer 7 is laminated on the outer peripheral side of the molding drum 11 to mold a green tire. During vulcanizing the green tire, the rubber composition of the sealant layer 9 is changed into a gel-like sealant substance. <P>COPYRIGHT: (C)2004,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for manufacturing a pneumatic tire having a puncture prevention function, and more specifically, a self-sealing in which a sealant layer formed by decomposing a rubber component with peroxide is arranged inside a crown portion. The present invention relates to a tire manufacturing method.

[0002]

2. Description of the Related Art With the development of highways, an adhesive sealant layer has been formed on the inside of the crown portion in order to ensure the safety of the vehicle when a tire steps on a nail or the like while driving. There is known a self-sealing tire in which a sealant substance adheres to a nail or the like to exert a sealing effect when the above reaches the inside of the tire.

The adhesive sealant is stored from the viewpoint of ensuring self-sealing property over the entire tread surface of the tire, from the viewpoint that the sealant material does not flow due to the centrifugal force accompanying high speed running, and further from the viewpoint of not impairing the uniformity of the tire. It is required that the sealant material does not flow under its own weight during parking or parking.

Particularly, when the temperature of the tire rises due to high-speed running, the sealant substance whose viscosity has decreased moves downward due to its own weight after running and cannot return to its original state as the temperature drops, which greatly impairs tire uniformity. Will be done.

Pneumatic tires which prevent the flow of a sealant substance disposed inside the tire and ensure a sealing property over the entire tread surface of the tire are disclosed, for example, in Japanese Utility Model Laid-Open No. 52-14860.
No. 3, JP-A-53-45803, JP-A-6-
It is disclosed in Japanese Patent No. 270283. However,
It is pointed out that these tires are commonly obtained by a peculiar manufacturing method and have very poor productivity.

[0006]

SUMMARY OF THE INVENTION An object of the present invention is to prevent the flow of a sealant substance, thereby ensuring a sealing property over the entire tread surface of a tire, maintaining the uniformity of the tire, and being excellent in productivity. A method for manufacturing a sealed tire is provided.

[0007]

The method for producing a self-sealing tire of the present invention for achieving the above object is a self-sealing tire in which a sealant layer formed by decomposing a rubber component with a peroxide is disposed inside a crown portion. In the method for producing, a cover rubber layer is wound on the outer peripheral side of the molding drum, and a sheet material of the rubber composition constituting the sealant layer and the sealant layer are divided into a plurality of regions on the outer peripheral side of the cover rubber layer. A partitioning material is wound, and another tire constituent member is further laminated on the outer peripheral side of the molding drum to mold a green tire, and the rubber composition of the sealant layer is a gel sealant substance during vulcanization of the green tire. It is characterized by changing to.

As described above, the sheet material of the rubber composition constituting the sealant layer and the partition material dividing the sealant layer into a plurality of regions are laminated on the outer peripheral side of the cover rubber layer, and the rubber composition of the sealant layer is formed during vulcanization. By changing the substance into a gel-like sealant substance and causing it to flow between the partition members, the gel-like sealant substance can be held in a state of being partitioned by the partition member. Therefore, it is possible to prevent the flow of the sealant substance, maintain the sealing property over the entire tire tread, and maintain the uniformity of the tire. Also,
In preventing the flow of the sealant material as described above,
Since it suffices to stack the partition material on the solid sheet material forming the sealant layer in the molding step, the productivity of the self-sealing tire can be significantly improved.

In the present invention, it is preferable to use a belt-shaped rubber material as the partition material. By winding such a band-shaped rubber material around the outer peripheral side of the molding drum and appropriately selecting the interval in the tire axial direction of the band-shaped rubber material and the number of windings, a partition member having a desired compartment shape can be formed. . That is, in the molding process, it is possible to arbitrarily select the variation of the partition material according to the tire size and the like.

[0010]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The structure of the present invention will be described in detail below with reference to the accompanying drawings. In each of the drawings, the same components are designated by the same reference numerals, and duplicated description will be omitted.

FIG. 1 illustrates a self-sealing tire obtained by the manufacturing method of the present invention, in which 1 is a crown portion, 2 is a sidewall portion, and 3 is a bead portion. A carcass layer 4 is mounted between the pair of left and right bead portions 3, 3.
The end portion is folded back around the bead core 5 from the inside of the tire to the outside. Carcass layer 4 in crown portion 1
The belt layer 6 is disposed on the outer peripheral side of the. An inner liner layer 7 is arranged inside the carcass layer 4.

A sealant layer 9 partitioned by a partition material 8 is arranged at a position corresponding to the crown portion 1 inside the inner liner layer 7, and the inner surface of the sealant layer 9 is covered with the sealant layer 9 inside. A cover rubber layer 10 is arranged.

As the rubber composition constituting the sealant layer 9, a rubber composition in which a rubber component decomposed by peroxide is mixed with peroxide, a filler or the like is used. Such a rubber composition is solid at the time of molding,
The rubber component is decomposed into a gel-like sealant substance by heating during vulcanization, and the sealant substance exhibits tackiness in the state of the finished tire.

FIG. 2 shows a method for manufacturing the self-sealing tire of the present invention. When manufacturing the above-mentioned self-sealing tire, as shown in FIG. 2, a rubber composition in which the cover rubber layer 10 is wound around the outer peripheral side of the molding drum 11 and the sealant layer 9 is formed on the outer peripheral side of the cover rubber layer 10. The sheet material 9A and the partition material 8 that divides the sealant layer 9 into a plurality of regions are wound. The winding order of the sheet material 9A and the partition material 8 is not particularly limited, and the partition material 8 may be wound after the sheet material 9A is wound as shown in the drawing.
Alternatively, the sheet material 9A may be wound after the partition material 8 is wound. After the sheet material 9A and the partition material 8 are wound, a green tire is formed by sequentially laminating the inner liner layer 7 and other tire constituent members (not shown) on the outer peripheral side of the forming drum 11 to form a green tire. Vulcanize in the mold.

Here, the rubber component constituting the sealant layer 9 is decomposed by the peroxide due to the heating associated with the vulcanization and converted into a gel-like sealant substance. On the other hand, the partition member 8 remains as it is and becomes a partition wall. Therefore, the gel-like sealant substance flows into between the partition members 8 under the influence of the internal pressure of the tire vulcanization bladder, and the partition members 8
It will be in a state of being partitioned by.

According to the above-described embodiment, a normal tire is used except that the cover rubber layer 10 and the solid sheet material 9A to be the sealant layer 9 and the partition material 8 are wound around the outer peripheral side of the molding drum 11 in the tire molding process. A self-sealing tire can be manufactured by the same method as the molding method. Therefore, the productivity of the self-sealing tire can be dramatically improved.

On the other hand, in the obtained self-sealing tire, the sealant layer 9 of the crown portion 1 is held between the inner liner layer 7 and the cover rubber layer 10 in a state in which the sealant layer 9 is partitioned by the partition member 8. The sealant substance hardly flows regardless of storage condition and use condition. Therefore, the sealing property can be secured over the entire tread surface of the tire, and the uniformity of the tire can be maintained. In particular, it is possible to improve the uniformity regarding the static balance and dynamic balance of the tire and improve the yield.

3 (a) to 3 (c) show a partition member 8 respectively.
FIG. In FIG. 3 (a),
The partition member 8 is formed by winding a belt-shaped rubber material around the outer peripheral side of the molding drum 11 to arrange the belt-shaped rubber material in the tire circumferential direction. In this case, based on the distance in the tire axial direction of the belt-shaped rubber material and the number of windings, in the molding process,
A variation of the partition member 8 can be arbitrarily selected. Of course, a strip-shaped rubber material serving as the partitioning material 8 may be spirally wound around the outer peripheral side of the molding drum 11. Partition material 8
Alternatively, as shown in FIGS. 3B and 3C, it is possible to use a lattice-shaped rubber material.

The material of the partitioning member 8 is not particularly limited, but it is preferable to use an unvulcanized rubber composition so that the partitioning member 8 can easily follow the deformation during tire molding. Depending on the case, it is also possible to use a vulcanized rubber composition, a synthetic resin or the like for the partition member 8.

In the sealant layer 9, the rubber component decomposed by peroxide may be polyisobutylene rubber or butyl rubber (IIR).
Butyl rubber is obtained by copolymerizing isobutylene with a small amount of isoprene and usually has an unsaturation degree of 2.2 mol% or less.

Examples of peroxides include acyl peroxides (eg, benzoyl peroxide, p-chlorobenzoyl peroxide), ketone peroxides (eg, methyl ethyl ketone peroxide),
Peroxyesters (for example, t-butylperoxyacetate, t-butylperoxybenzoate, t-
Butylperoxyphthalate), alkyl peroxides (eg, dicumyl peroxide, di-t-butylperoxybenzoate, 1,3-bis (t-butylperoxyisopropyl) benzene), hydroperoxides (eg, t-butyl hydroperoxide) and the like can be used.

The rubber composition for a sealant has a composition of 0.1% by weight based on 100 parts by weight of a rubber component decomposed by peroxide.
It is preferable to contain 2 to 10 parts by weight of peroxide. If the amount of the peroxide compounded is less than 0.2 parts by weight relative to 100 parts by weight of the peroxide-decomposed rubber component, the rubber component will not be sufficiently decomposed and the sealing effect will be insufficient. If it exceeds 10 parts by weight, the decomposition will proceed. Since the viscosity of the sealant is reduced, the sealant material is likely to flow due to centrifugal force when traveling at high speed.

In addition to the peroxide-decomposable rubber component, other rubber components can be added to the rubber composition for a sealant. The rubber component is not particularly limited as long as it can be used for a tire, and examples thereof include isoprene rubber, styrene butadiene rubber, butadiene rubber, natural rubber and the like.

Further, the rubber composition for a sealant contains
If necessary, a catalyst such as cobalt naphthenate is added to accelerate the decomposition of the rubber component by peroxide, an inorganic filler such as carbon black or silica is added, or an adhesive such as polybutene is added. Alternatively, a plasticizer such as an aromatic process oil, a naphthenic process oil, or a paraffinic process oil may be added. However, clay is not preferable because it hinders the decomposition of peroxide.

Since the cover rubber layer 10 plays a role of wrapping the sealant substance changed into a gel at the time of vulcanization of the tire, it is preferable that both widthwise end portions thereof are bonded to the inner liner layer 7. Therefore, it is preferable to use a material having good adhesiveness to the inner liner layer 7.

[0026]

As described above, according to the method for producing a self-sealing tire of the present invention, the rubber forming the seal rubber layer is wound around the outer peripheral side of the molding drum and the outer peripheral side of the cover rubber layer. A sheet material of the composition and a partition material that divides the sealant layer into a plurality of regions are wound, and another tire constituent member is further laminated on the outer peripheral side of the molding drum to mold a green tire, and the vulcanization of the green tire is performed. Since the rubber composition of the sealant layer is changed to a gel-like sealant substance inside, it becomes possible to manufacture a self-sealing tire with improved sealability and uniformity by preventing flow of the sealant substance with high productivity. .

[Brief description of drawings]

FIG. 1 is a half section view of a tire meridian illustrating a self-sealing tire obtained by a method for manufacturing a self-sealing tire of the present invention.

FIG. 2 is a cross-sectional view showing a molding step of the method for manufacturing a self-sealing tire of the present invention.

3 (a) to 3 (c) are partial plan views showing different aspects of the partitioning material in the present invention.

[Explanation of symbols]

1 tread section 2 Side wall part 3 bead part 4 carcass layers 5 bead core 6 belt layers 7 Inner liner layer 8 partition materials 9 Sealant layer 9A sheet material 10 Cover rubber layer 11 Molding drum

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Satoshi Makino             1-4-1 Chuo Stock Market, Wako City, Saitama Prefecture             Inside Honda Research Laboratory (72) Inventor Takayuki Toyoshima             1-4-1 Chuo Stock Market, Wako City, Saitama Prefecture             Inside Honda Research Laboratory F-term (reference) 4F212 AH20 VA02 VC02 VC03 VD20                       VK02                 4F213 AA45 AB03 AB20 AC06 AG22                       AH20 WM01 WM05 WM17 WM26                       WM27 WM29 WM35

Claims (2)

[Claims] 1. A method for producing a self-sealing tire in which a sealant layer obtained by decomposing a rubber component with peroxide is disposed inside a crown portion, wherein a cover rubber layer is wound around an outer peripheral side of a molding drum. A sheet material of the rubber composition that constitutes the sealant layer and a partition material that divides the sealant layer into a plurality of regions are wound on the outer peripheral side of the layer, and another tire constituent member is further laminated on the outer peripheral side of the molding drum. A method for producing a self-sealing tire in which a rubber composition of the sealant layer is changed into a gel-like sealant substance during vulcanization of the green tire by vulcanizing the green tire. 2. The method for manufacturing a self-sealing tire according to claim 1, wherein the partition member is made of a belt-shaped rubber material.