JP6676467B2 - Manufacturing method for pneumatic tires - Google Patents

Description

  The present invention relates to a method for manufacturing a pneumatic tire.

  Conventionally, the inner liner provided on the inner surface of the tire to maintain the internal pressure of the tire is formed by using a sheet-like air barrier resin film layer instead of a rubber layer mainly made of, for example, butyl rubber, etc. Various tires have been proposed (for example, Patent Document 1).

JP 2013-216200 A

Here, a pneumatic tire having an inner liner formed of the above resin film layer can be made thinner as compared with a case having an inner liner made of butyl rubber as a main raw material. However, there are the following problems in the manufacturing process. That is, in the manufacturing process, the tire is manufactured by sequentially laminating the tire constituent members on the tire forming drum from the inner liner to the outer side of the tire. And, when the resin film layer as described above is used as the inner liner, the thickness of the resin film layer itself is small and the handling property is not good, so that the resin film layer is appropriately wound on the tire forming drum, and further, It was not easy to appropriately stack other tire components.
In order to solve this problem, it is conceivable to use a sheet-like laminate in which a resin film layer and a sheet-like rubber layer are laminated, for example, as the inner liner. By laminating the rubber layer to form a laminate as described above, the handleability in the manufacturing process is improved as compared with the case of using only the resin film layer, and the productivity of the tire can be improved. Further, by providing the rubber layer, the concentration of stress at the time of bending the tire on the resin film layer having insufficient bending resistance can be reduced, and the durability of the inner liner can be improved.

  However, when a laminate formed by laminating a rubber layer with the resin film layer is used as an inner liner, the inner liner has one end in the longitudinal direction of the laminate and the other end in the longitudinal direction of the laminate. Although they are formed by being superimposed, there is a possibility that air may enter the superimposed portion. More specifically, the inner liner is formed by bonding and joining a resin film layer at one end in the longitudinal direction and a rubber layer at the other end in the longitudinal direction of the laminate. In some cases, air may enter between the layers and remain. The tire having the inner liner containing air may not be able to sufficiently maintain the internal pressure.

  Then, an object of the present invention is to provide a manufacturing method of a pneumatic tire which can manufacture a pneumatic tire provided with an inner liner which controlled entry of air into a joint part.

The method for manufacturing a pneumatic tire of the present invention is a method for manufacturing a pneumatic tire including an inner liner including a sheet-like laminate formed by laminating a resin film layer and a rubber layer,
In the laminate, the rubber layer is formed on one surface of the resin film layer on which the rubber layer is laminated, at least at one end in the longitudinal direction among the ends of the resin film layer, and the rubber layer is formed on one side of the resin film layer. Is not located on the side surface,
An inner liner is formed by overlapping the resin film layer at one end in the longitudinal direction of the laminate with the resin film layer at the other end in the longitudinal direction of the laminate.
According to the method for manufacturing a pneumatic tire of the present invention, it is possible to manufacture a pneumatic tire including an inner liner that suppresses air from entering a joint portion.

In the method for manufacturing a pneumatic tire according to the present invention, it is preferable that in the pneumatic tire, the resin film layer of the inner liner is located on the tire inner side than the rubber layer.
According to this configuration, it is possible to secure an interval between the resin film layer and the carcass adjacent to the inner liner, and it is possible to eliminate the possibility of penetration.

In the method for manufacturing a pneumatic tire according to the present invention, the inner liner preferably has an overlap between the one end in the longitudinal direction and the other end in the longitudinal direction of the laminate of 5 to 20 mm.
According to this configuration, it is possible to efficiently manufacture a pneumatic tire including an inner liner that sufficiently secures internal pressure retention.
In the present invention, the overlap between the one end in the longitudinal direction and the other end in the longitudinal direction of the laminate refers to a length measured along the longitudinal direction of the laminate (the tire circumferential direction of the inner liner).

In the method for manufacturing a pneumatic tire according to the present invention, the thickness of the laminate is preferably 1.5 mm or less.
According to this configuration, the weight of the tire can be reduced.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of a pneumatic tire which can manufacture the pneumatic tire provided with the inner liner which ensured sufficient internal pressure retention can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS It is sectional drawing which shows the pneumatic tire which can be manufactured by the manufacturing method of the pneumatic tire which concerns on one Embodiment of this invention. FIG. 2 is an enlarged cross-sectional view showing an inner liner (laminated body) of the pneumatic tire in FIG. 1 in a state immediately before overlapping each end of the laminated body (a forming drum that can be used to form the inner liner). Is omitted). FIG. 2 is a diagram illustrating a manufacturing process of a laminate for forming the inner liner of FIG. 1.

An embodiment of the present invention will be described below with reference to the drawings.
FIG. 1 is a cross-sectional view illustrating a tire 1 that can be manufactured by a method for manufacturing a pneumatic tire (hereinafter, also referred to as a tire) according to an embodiment of the present invention, and FIG. Of the inner liner 7 is illustrated by an enlarged sectional view.

First, a tire 1 that can be manufactured by the tire manufacturing method of the present embodiment will be described.
The tire 1 that can be manufactured by the tire manufacturing method of the present embodiment includes, for example, a tread portion 2, a pair of bead portions 3, and a portion between the tread portion 2 and each bead portion 3 as illustrated in FIG. 1. And a pair of side wall portions 4 extending. Further, the tire 1 includes a carcass 5 extending in a toroidal shape between the pair of bead portions 3 to reinforce these portions, and at least one carcass 5 disposed outside the crown portion of the carcass 5 in the tire radial direction. Here, a belt 6 composed of two belt layers and an inner liner 7 provided inside the carcass 5 are provided.

  For example, as shown in FIG. 2, the inner liner 7 is formed on a resin film layer 81 and on one surface S (one surface in the thickness direction of the resin film layer) of the resin film layer 81, here, in the tire radial direction. It is formed using a sheet-shaped laminate 8 having a rubber layer 82 laminated on the surface (the radially outer surface of the inner liner 7 having a circular cross section).

  The resin film layer 81 has an air barrier property for maintaining the internal pressure of the tire 1, and is not particularly limited. For example, a polyamide resin, a polyvinylidene chloride resin, a polyester resin, ethylene-vinyl A film or sheet made of an alcohol copolymer resin or the like can be used. In particular, as the resin film layer 81, for example, a film made of an ethylene-vinyl alcohol copolymer resin can be suitably used. The film or sheet can be produced by, for example, extrusion molding.

  The resin film layer 81 may have a thickness of, for example, 40 to 100 μm. By setting the thickness of the resin film layer 81 to 40 μm or more, a sufficient air barrier property can be imparted, and by setting the thickness to 100 μm or less, the reduction in bending resistance due to the resin film layer 81 being too thick, An increase in weight can be prevented. In addition, from a similar viewpoint, the thickness is more preferably 55 to 85 μm.

  For the rubber layer 82, for example, natural rubber, synthetic isoprene rubber, polybutadiene rubber, styrene-butadiene copolymer rubber, styrene-isoprene copolymer rubber, butyl rubber, or the like can be used. The rubber layer 82 may or may not have an air barrier property. In this embodiment, a rubber composition having no air barrier property is used.

  The rubber layer 82 may have a thickness of, for example, 200 to 500 μm. By setting the thickness of the rubber layer 82 to 200 μm or more, the handleability of the laminate 8 can be sufficiently improved. be able to. In addition, from a similar viewpoint, the thickness is more preferably set to 300 to 400 μm.

As shown in FIG. 2, the laminate 8 is laminated on the resin film layer 81 and one surface S (one surface in the thickness direction; the upper surface in FIG. 2) of the resin film layer 81. And a rubber layer 82. The laminate 8 has a rectangular shape, and the longitudinal length of the laminate 8 is slightly longer than the length of one circumference of the inner liner 7.
In addition, the rubber layer 82 in the laminate 8 has at least one of the ends (longitudinal ends and short-side ends) of the resin film layer 81 on one surface S of the resin film layer 81. At one end in the direction, the rubber layer 82 is not located on one surface S of the resin film layer 81. Specifically, in the illustrated example, at least one longitudinal end 83 of the laminated body 8 does not have the rubber layer 82 laminated on the resin film layer 81, and the longitudinal end 83 is formed of the resin film layer 81. It is only. The length of the rubber layer 82 in the longitudinal direction is shorter than that of the resin film layer 81, and on one surface S of the resin film layer 81, near the other end of the resin film layer 81 in the longitudinal direction. positioned. As in the illustrated example, the other end in the longitudinal direction of the rubber layer 82 and the other end in the longitudinal direction of the resin film layer 81 in the laminate 8 are located at the same position (aligned in the longitudinal direction). Is preferable from the viewpoint of the ease of manufacturing the laminate 8. However, the other end in the longitudinal direction of the rubber layer 82 and the other end in the longitudinal direction of the resin film layer 81 in the laminate 8 may not be located at the same position. Is located at the other end in the longitudinal direction from the other end in the longitudinal direction of the resin film layer 81, or the other end in the longitudinal direction of the rubber layer 82 is one end in the longitudinal direction than the other end in the longitudinal direction of the resin film layer 81. It may be located on the side. Although not shown, the rubber layer 82 is formed not only at one end in the longitudinal direction of the resin film layer 81 on the one surface S of the resin film layer 81 but also at the end in the short direction of the resin film layer 81. May not be located on one side surface S of the resin film layer 81.

  The length in the longitudinal direction of the resin film layer 81 of the laminate 8 is longer than the length of one circumference of the inner liner by the length of the overlapping portion of the laminate 8 when forming the inner liner as described later. ing. Further, the longitudinal length of the rubber layer 82 can be shorter than the longitudinal length of the resin film layer 81.

In addition, it is preferable that the laminated body 8 has a thickness of, for example, 1.5 mm or less. By setting the thickness of the laminate 8 to 1.5 mm or less, it is possible to prevent an increase in weight due to excessive thickness.
In addition, the resin film layer 81 of the laminate 8 can be a single layer. Further, the rubber layer 82 can be formed as one layer. For example, when a rubber layer is laminated on the other surface of the resin film layer 81 to form two layers, the other surface of the resin film layer is formed. Preferably, at least at the other end in the longitudinal direction of the resin film layer, the rubber layer is not located on the other surface of the resin film layer.

Subsequently, a method for manufacturing a tire according to the present embodiment will be described.
The method of manufacturing a tire according to the present embodiment includes, for example, forming at least the resin film layer on one end portion 83 in the longitudinal direction of the laminate 8 and the other end portion in the longitudinal direction of the laminate 8 on a molding drum for tire molding. The step of forming the inner liner 7 by superimposing the resin film layer 84 on the inner liner 7 is provided. Further, in this embodiment, after the inner liner 7 is formed, a carcass, a belt, a tread rubber, and the like are arranged outside the inner liner 7 and molded to obtain a raw tire before vulcanization. In a vulcanizing mold, while vulcanizing the tire while forming the shape of the outer surface including the tread pattern, whereby the tire 1 can be manufactured.

More specifically, in the step of forming the inner liner 7 in this tire manufacturing method, for example, the resin film layer 81 of the above-mentioned laminate 8 is placed radially inward on a forming drum for forming a tire. The laminated body 8 is wound on a forming drum such that the longitudinal direction of the body 8 is parallel to the tire circumferential direction. Then, the resin film layer 81 at one longitudinal end 83 of the laminate 8 and the resin film layer 81 at the other longitudinal end 84 of the laminate 8 are overlapped. Note that, in the illustrated example, the lamination is performed from one end in the thickness direction of the one end portion 83 in the longitudinal direction (here, the outer side in the tire radial direction; in FIG. The other longitudinal end portion 84 of the body 8 is overlapped.
At this time, since the rubber layer 82 in the laminate 8 is not located at one longitudinal end on the one surface S of the resin film layer 81, one end 83 and the other end 84 of the laminate 8 Can be overlapped so that the resin film layers 81 of the first and second resin films contact each other.

  Therefore, the method for manufacturing a tire according to the present embodiment includes the step of forming the inner liner 7 as described above, so that the inner liner 7 has the end portions 83 and 84 (the joint portions of the inner liner 7) where the laminates 8 overlap. In (2), the resin film layers 81 are jointed so as to adhere to each other. Therefore, it is possible to prevent air from entering at the overlapping ends 83 and 84, which can occur when the resin film layer 81 and the rubber layer 82 are formed so as to be in contact with each other. Therefore, it is possible to manufacture a pneumatic tire including the inner liner in which air is prevented from entering the joint.

  In the tire manufacturing method of this example, the laminated body 8 was disposed on the molding drum for tire molding so that the resin film layer 81 of the laminated body 8 was located inside the tire, but the rubber layer 82 was placed inside the tire. You can also. However, disposing the laminate 8 such that the resin film layer 81 of the laminate 8 is on the tire inner side (that the resin film layer 81 of the inner liner 7 is located on the tire inner side of the rubber layer 82) is a resin film. An interval between the layer 81 and the carcass adjacent to the inner liner 7 can be ensured. For example, it can be caused by a rubber component flowing during tire vulcanization and the resin film layer 81 entering between the cords of the carcass. It is possible to eliminate the risk of penetration.

  In addition, in the inner liner, the overlap between the one end 83 and the other end 84 in the longitudinal direction of the laminate 8 is preferably 5 to 20 mm. The adhesion of the overlapping ends 83 and 84 can be ensured, and the influence on the uniformity of the tire and increase in tire weight, for example, due to the overlapping ends 83 and 84 becoming too large can be suppressed. .

  Furthermore, in the tire manufacturing method, after the longitudinal one end portion 83 and the other end portion 84 of the laminate 8 are overlapped to form the inner liner 7, a tire member such as a carcass can be laminated. After the longitudinal one end portion 83 and the other end portion 84 of the body 8 are overlapped, at least a part of the overlapping end portions 83 and 84 can be thermocompression-bonded. The overlapping ends 83 and 84 of the laminated body 8 are bonded by heating at the time of vulcanization of the tire, but by laminating at least a part of the overlapping portion by thermocompression before laminating a tire member such as a carcass. The end portions 83 and 84 can be temporarily fixed to each other, and the inner liner 7 can be reliably formed.

Here, a method for manufacturing the laminate 8 will be described.
As shown in FIG. 3, a method for manufacturing the laminate 8 includes preparing a rubber sheet 92 and a resin film 91 having a size capable of manufacturing an inner liner for a plurality of tires. The horizontal direction in FIG. 3 is the horizontal direction of the rubber sheet 92 and the resin film 91 (the longitudinal direction of the rubber layer 82 and the resin film layer 81 (the circumferential direction of the inner liner)), and the front and rear directions in FIG. Is the vertical direction of the rubber sheet 92 and the resin film 91 (the short direction of the rubber layer 82 and the resin film layer 81 (the tire width direction of the inner liner)).
Note that the rubber sheet 92 and the resin film 91 may have substantially the same area. Further, the rubber sheet 92 and the resin film 91 may be of a size capable of manufacturing an inner liner for one tire.

Next, the rubber sheet 92 and the resin film 91 are overlapped and laminated. At this time, the resin film 91 is overlapped with the rubber sheet 92 while being shifted to one side in the left-right direction. The resin film 91 and the rubber sheet 92 are shifted and overlapped to form one end 83 in the longitudinal direction of the laminate 8.
Subsequently, the end on the other side in the left-right direction of the laminate 9 in which the rubber sheet 92 and the resin film 91 are laminated is cut. When cutting the other end in the left-right direction, the length in the left-right direction of the resin film 91 is set to a desired length in the longitudinal direction of the laminate 8. By cutting in this manner, the other end portion 84 in the longitudinal direction of the laminate 8 can be formed.

  Then, after cutting the other end in the left-right direction of the laminate 9, the laminate 9 is cut in the up-down direction. When cutting in the up-down direction, the desired length of the laminate 8 in the short direction is set. By cutting in this manner, a plurality of laminates 8 can be formed.

  In the illustrated method, the rubber sheet 92 and the resin film 91 have substantially the same area, but are laminated using the rubber sheet 92 and the resin film 91 whose length in the left-right direction is shorter than the resin film 91. The body 8 can also be manufactured. When the rubber sheet 92 and the resin film 91 in which the length in the left-right direction of the rubber sheet 92 is shorter than the resin film 91, the resin film 91 is moved to one side in the left-right direction with respect to the rubber sheet 92. The laminated body 8 is manufactured by cutting the laminated body 9 so that the resin film 91 has the same length as the resin film layer 81 of the laminated body 8 in the longitudinal direction. You can also.

  As described above, the embodiments of the present invention have been described with reference to the drawings.However, the method of manufacturing a pneumatic tire of the present invention is not limited to the above-described example. , And can be appropriately changed.

  ADVANTAGE OF THE INVENTION According to this invention, the manufacturing method of a pneumatic tire which can manufacture a pneumatic tire provided with the inner liner which suppressed entry of air into the joint part is provided.

1: tire, 2: tread, 3: bead, 4: sidewall, 5: carcass, 6: belt, 7: inner liner, 8: laminate, 81: resin film layer, 82: rubber layer, 83 : One end in the longitudinal direction, 84: The other end in the longitudinal direction, 9: Laminated body, 91: Resin film, 92: Rubber sheet, S: One side surface

Claims (5)

A method for manufacturing a pneumatic tire including an inner liner including a sheet-like laminate formed by laminating a resin film layer and a rubber layer,
In the laminate, the rubber layer is formed on one side surface of the resin film layer on which the rubber layer is laminated, at least at one end in the longitudinal direction among the ends of the resin film layer, and the rubber layer is formed on one side of the resin film layer. It is not located on the side surface, the other longitudinal end of the rubber layer and the other longitudinal end of the resin film layer are located at the same position,
An inner liner is formed by overlapping the resin film layer at one end in the longitudinal direction of the laminate with the resin film layer at the other end in the longitudinal direction of the laminate. Production method.    The method for manufacturing a pneumatic tire according to claim 1, wherein the resin film layer of the inner liner is located on the inner side of the rubber layer with respect to the rubber layer.    The method for manufacturing a pneumatic tire according to claim 1, wherein the inner liner has an overlap between the one end in the longitudinal direction and the other end in the longitudinal direction of the laminate of 5 to 20 mm.    The method for manufacturing a pneumatic tire according to any one of claims 1 to 3, wherein the thickness of the laminate is 1.5 mm or less. The method for manufacturing a pneumatic tire according to any one of claims 1 to 4, wherein the resin film layer has a thickness of 40 to 100 m, and the rubber layer has a thickness of 200 to 500 m.

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