JP3837364B2 - Self-sealing tire manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for manufacturing a pneumatic tire having a puncture-preventing function, and more particularly to a method for manufacturing a self-sealed tire in which a sealant layer obtained by decomposing a rubber component with a peroxide is disposed inside a crown portion.
[0002]
[Prior art]
With the development of highways, an adhesive sealant layer is formed on the inner side of the crown to ensure vehicle safety when the tires step on nails while driving. A self-sealing tire is known in which the sealant material adheres to a nail or the like and exhibits a seal effect when the pressure reaches the point.
[0003]
In such an adhesive sealant layer, the sealant substance does not flow due to the centrifugal force associated with high-speed running from the viewpoint of ensuring self-sealability over the entire tire tread surface, and further, during storage or from the viewpoint of not impairing tire uniformity. It is required that the sealant material does not flow due to its own weight when parking.
[0004]
In particular, when the temperature of the tire increases due to high-speed driving, the sealant material whose viscosity has decreased moves downward due to its own weight after driving, and if it does not return as it is due to the decrease in temperature, the tire uniformity is greatly hindered. Become.
[0005]
Pneumatic tires that prevent the flow of the sealant substance disposed on the inner side of the tire and ensure the sealability over the entire tire tread are disclosed in, for example, Japanese Utility Model Laid-Open Nos. 52-148603, 53-45803, and Hei 6 -270283. However, it has been pointed out that these tires are commonly obtained by a specific manufacturing method and have very poor productivity.
[0006]
[Problems to be solved by the invention]
An object of the present invention is to provide a method for producing a self-sealing tire that ensures sealability over the entire tire tread, maintains tire uniformity, and is excellent in productivity by preventing the flow of a sealant substance. It is.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, a method for producing a self-sealing tire according to the present invention includes a sealant layer formed by decomposing a rubber component with a peroxide between a cover rubber layer and an inner liner layer provided on the inner surface of a tire in a crown portion. In the method of manufacturing a self-sealing tire having a structure, a sheet-like cover rubber material that becomes the cover rubber layer is wound around the outer peripheral side of the molding drum, and a sheet-like cover rubber layer that becomes the sealant layer is formed on the outer peripheral side of the cover rubber material. A sealant filler is wound, a sheet-like inner liner material that becomes the inner liner layer is wound on the outer peripheral side of the sealant filler, and another tire constituent member is laminated on the outer peripheral side of the inner liner material. A step of forming a tire and changing the sealant filler into a gel sealant substance during vulcanization of the green tire And a convex portion serving as a partition partitioning the sealant layer into a plurality of regions is provided on a contact surface of the inner liner material or the cover rubber material with the sealant filler. .
[0008]
In this way, a convex portion serving as a partition wall that divides the sealant layer into a plurality of regions is provided on the contact surface of the inner liner material or the cover rubber material with the sealant filler, and the sealant filler is gel-like sealant during vulcanization. The gel-like sealant substance can be held in a state of being partitioned by the partition walls by being changed into a substance and flowing between the partition walls made of the convex portions. Accordingly, the flow of the sealant material can be prevented, the sealing performance can be maintained over the entire tire tread, and the uniformity of the tire can be maintained. Moreover, when the flow of the sealant material is prevented as described above, it is only necessary to use an inner liner material or a cover rubber material provided with a convex portion in the molding process, thereby greatly improving the productivity of the self-sealing tire. be able to.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, the configuration of the present invention will be described in detail with reference to the accompanying drawings. In each figure, the same components are denoted by the same reference numerals, and redundant description is omitted.
[0010]
FIG. 1 illustrates a self-sealing tire obtained by the production method of the present invention, wherein 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 and 3, and an end portion thereof is folded around the bead core 5 from the inside to the outside of the tire. A belt layer 6 is disposed on the outer peripheral side of the carcass layer 4 in the crown portion 1. Further, an inner liner layer 7 is disposed inside the carcass layer 4.
[0011]
A sealant layer 9 partitioned by a partition wall 8 is disposed at a position corresponding to the crown portion 1 inside the inner liner layer 7, and a cover rubber layer 10 covering the sealant layer 9 is disposed inside the sealant layer 9. Has been. The cover rubber layer 10 preferably has both ends in the width direction joined to the inner liner layer 7 in order to wrap up the sealant substance that has changed into a gel during vulcanization of the tire. It is preferable to use a material having good adhesiveness with the inner liner layer 7.
[0012]
As the rubber composition constituting the sealant layer 9, a rubber composition in which a peroxide, a filler or the like is blended with a rubber component decomposed by peroxide is used. Such a rubber composition is solid at the time of molding, and the rubber component is decomposed by heating at the time of vulcanization to become a gel-like sealant material, and the sealant material exhibits adhesiveness in the state of the finished tire.
[0013]
FIG. 2 shows a method for manufacturing a self-sealing tire according to the first embodiment of the present invention. When manufacturing the above-described self-sealing tire, as shown in FIG. 2, a cover rubber material 20 that becomes the cover rubber layer 10 is wound around the outer peripheral side of the molding drum 11, and the sealant layer 9 is wound around the outer peripheral side of the cover rubber material 20. The sealant filler 19 is wound, and the inner liner material 17 serving as the inner liner layer 7 is wound around the outer periphery of the sealant filler 19. The inner liner material 17 used here is formed by forming at least one convex portion 17 a extending continuously on the contact surface with the sealant filler 19. This convex part 17a becomes the above-mentioned partition 8 after vulcanization, and partitions the sealant layer 9 into a plurality of regions. After winding the inner liner material 17, other tire constituent members (not shown) are sequentially laminated on the outer peripheral side of the inner liner material 17 to form a green tire, and the green tire is vulcanized in a mold.
[0014]
Here, the rubber component of the sealant filler 19 is decomposed by peroxide due to heating accompanying vulcanization, and changes into a gel sealant substance. On the other hand, the convex portion 17 a of the inner liner material 17 remains as it is, and becomes a partition wall 8. Therefore, the gel sealant material flows between the partition walls 8 while being affected by the internal pressure of the tire vulcanization bladder, and is in a state of being partitioned by the partition walls 8.
[0015]
FIG. 3 shows a method for manufacturing a self-sealing tire according to the second embodiment of the present invention. When manufacturing the above-described self-sealing tire, as shown in FIG. 3, a cover rubber material 20 to be the cover rubber layer 10 is wound around the outer peripheral side of the molding drum 11, and the sealant layer 9 is wound around the outer peripheral side of the cover rubber material 20. The sealant filler 19 is wound, and the inner liner material 17 serving as the inner liner layer 7 is wound around the outer periphery of the sealant filler 19. The cover rubber material 20 used here is formed by forming at least one convex portion 20 a extending continuously on the contact surface with the sealant filler 19. This convex part 20a becomes the above-mentioned partition 8 after vulcanization, and partitions the sealant layer 9 into a plurality of regions. After winding the inner liner material 17, other tire constituent members (not shown) are sequentially laminated on the outer peripheral side of the inner liner material 17 to form a green tire, and the green tire is vulcanized in a mold.
[0016]
Here, the rubber component of the sealant filler 19 is decomposed by peroxide due to heating accompanying vulcanization, and changes into a gel sealant substance. On the other hand, the convex portion 20 a of the cover rubber material 20 remains as it is, and becomes a partition wall 8. Therefore, the gel sealant material flows between the partition walls 8 while being affected by the internal pressure of the tire vulcanization bladder, and is in a state of being partitioned by the partition walls 8.
[0017]
According to each said embodiment, in the tire shaping | molding process, the method similar to the normal tire shaping | molding method except using the inner liner material 17 which provided the convex part 17a, or the cover rubber material 20 which provided the convex part 20a. Thus, a self-sealing tire can be manufactured. Therefore, the productivity of self-sealing tires can be dramatically improved.
[0018]
On the other hand, since the obtained self-sealing tire holds the sealant layer 9 of the crown portion 1 between the inner liner layer 7 and the cover rubber layer 10 in a state where the sealant layer 9 is partitioned by the partition walls 8, the storage state and use of the tire The sealant material hardly flows regardless of the state. Therefore, it is possible to ensure the sealing performance over the entire tire tread and to maintain the uniformity of the tire. In particular, it is possible to improve the uniformity regarding the static balance and the dynamic balance of the tire and improve the yield.
[0019]
The partition wall 8 obtained from the convex portion 17a of the inner liner material 17 or the convex portion 20a of the cover rubber layer 20 does not necessarily need to completely divide the sealant layer 9, and at least from the inner liner layer 7 or the cover rubber layer 10. Any material may be used as long as it protrudes toward the sealant layer 9 and prevents the sealant material from flowing.
[0020]
4 (a) to 4 (c) show different modes of the partition wall 8, respectively. In Fig.4 (a), the partition 8 is comprised from the several convex part extended in a tire peripheral direction. 4 (b) and 4 (c), the partition wall 8 is composed of a grid-like convex portion. In the present invention, the partition wall shape is determined on the basis of the shape of the projections imparted to the inner liner material or the cover rubber material. Therefore, variations in the partition wall 8 can be arbitrarily selected for each tire size in the molding process.
[0021]
In the present invention, examples of the rubber component decomposed by peroxide include polyisobutylene rubber and butyl rubber (IIR). Butyl rubber is obtained by copolymerizing a small amount of isoprene with isobutylene, and usually has a degree of unsaturation of 2.2 mol% or less.
[0022]
Peroxides include acyl peroxides (eg, benzoyl peroxide, p-chlorobenzoyl peroxide), ketone peroxides (eg, methyl ethyl ketone peroxide), peroxy esters (eg, t-butyl peroxide ester, t-butylperoxybenzoate, t-butylperoxyphthalate), alkyl peroxides (eg, dicumyl peroxide, di-t-butylperoxybenzoate, 1,3-bis (t-butylperoxyisopropyl) benzene ), Hydroperoxides (for example, t-butyl hydroperoxide) and the like can be used.
[0023]
The rubber composition for sealant preferably contains 0.2 to 20 parts by weight of peroxide with respect to 100 parts by weight of the rubber component decomposed by peroxide. If the amount of peroxide is less than 0.2 parts by weight with respect 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, and if it exceeds 20 parts by weight, decomposition will proceed. Since the viscosity is too low, the sealant material easily flows due to centrifugal force during high-speed running.
[0024]
In addition to the peroxide-decomposable rubber component, other rubber components can be blended with the rubber composition for 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, and natural rubber.
[0025]
In addition, a catalyst such as cobalt naphthenate or an inorganic filler such as carbon black or silica is added to the rubber composition for sealant as necessary to promote the decomposition of the rubber component by peroxide. Alternatively, an adhesive such as polybutene may be added, or a plasticizer such as an aromatic process oil, a naphthene process oil, or a paraffin process oil may be added. However, clay is not preferable because it prevents the decomposition of peroxide.
[0026]
【The invention's effect】
As described above, according to the method for manufacturing a self-sealing tire of the present invention, a sheet-like cover rubber material that becomes a cover rubber layer is wound around the outer peripheral side of the molding drum, and the sealant layer is formed on the outer peripheral side of the cover rubber material. A sheet-like sealant filler is wound, a sheet-like inner liner material that is an inner liner layer is wound on the outer peripheral side of the sealant filler, and another tire component is laminated on the outer peripheral side of the inner liner material When the green tire is molded and the sealant filler is changed to a gel sealant substance during vulcanization of the green tire, the sealant layer is formed on the contact surface of the inner liner material or the cover rubber material with the sealant filler. A cell with improved sealing and uniformity by preventing the flow of the sealant material by providing a convex part that partitions the wall into multiple regions It is possible to manufacture a sealing tires with high productivity.
[Brief description of the drawings]
FIG. 1 is a half sectional view of a tire meridian illustrating a self-sealing tire obtained by a method for producing a self-sealing tire of the present invention.
FIG. 2 is a cross-sectional view showing a molding process of the self-sealing tire manufacturing method according to the first embodiment of the present invention.
FIG. 3 is a cross-sectional view showing a molding process of a self-sealing tire manufacturing method according to a second embodiment of the present invention.
FIGS. 4A to 4C are partial plan views showing different embodiments of the partition walls in the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Tread part 2 Side wall part 3 Bead part 4 Carcass layer 5 Bead core 6 Belt layer 7 Inner liner layer 8 Partition wall 9 Sealant layer 10 Cover rubber layer 11 Molding drum 17 Inner liner material 17a Convex part 19 Sealant filler 20 Cover rubber material 20a Convex

Claims (2)

In a method for manufacturing a self-sealing tire in which a sealant layer obtained by decomposing a rubber component with a peroxide is disposed between a cover rubber layer and an inner liner layer provided on an inner surface of a tire in a crown portion, A sheet-like cover rubber material serving as the cover rubber layer is wound, a sheet-like sealant filler serving as the sealant layer is wound around the outer periphery of the cover rubber material, and the inner liner is wound around the outer periphery of the sealant filler. A sheet-like inner liner material to be a layer is wound, and another tire constituent member is laminated on the outer peripheral side of the inner liner material to form a green tire, and the sealant filler is added during vulcanization of the green tire. A step of changing to a gel-like sealant substance, and a contact surface of the inner liner material with the sealant filler. Method for producing a self-sealing tire having a convex portion serving as a barrier rib partitioning the sealant layer into a plurality of regions. In a method for manufacturing a self-sealing tire in which a sealant layer obtained by decomposing a rubber component with a peroxide is disposed between a cover rubber layer and an inner liner layer provided on an inner surface of a tire in a crown portion, A sheet-like cover rubber material serving as the cover rubber layer is wound, a sheet-like sealant filler serving as the sealant layer is wound around the outer periphery of the cover rubber material, and the inner liner is wound around the outer periphery of the sealant filler. A sheet-like inner liner material to be a layer is wound, and another tire constituent member is laminated on the outer peripheral side of the inner liner material to form a green tire, and the sealant filler is added during vulcanization of the green tire. A step of changing to a gel-like sealant substance, and a contact surface of the cover rubber material with the sealant filler; Method for producing a self-sealing tire having a convex portion serving as a barrier rib partitioning Zealand layer into a plurality of regions.

Images