WO2021112049A1

WO2021112049A1 - Fiber, method for manufacturing resin-coated cord, method for manufacturing pneumatic tire

Info

Publication number: WO2021112049A1
Application number: PCT/JP2020/044558
Authority: WO
Inventors: 誓志今
Original assignee: 株式会社ブリヂストン
Priority date: 2019-12-05
Filing date: 2020-11-30
Publication date: 2021-06-10
Also published as: JP2021088789A

Abstract

A fiber comprises a plurality of metal strands and a plurality of resin strands formed from a thermoplastic resin. By heating the fibers, the resin strands are melted and a bonding resin is formed that bonds the plurality of metal strands with the melted resin.

Description

Manufacturing method of fiber and resin coated cord, manufacturing method of pneumatic tire

This disclosure relates to a method for manufacturing fibers and resin-coated cords, and a method for manufacturing pneumatic tires.

US Publication No. 2014/311120 describes a reinforcement cord provided on a two-layer belt that constitutes a pneumatic tire. The reinforcing cord is formed by including a plurality of spirally twisted metal strands and a filled rubber filled between the plurality of metal strands.

Conventionally, a plurality of metal wires constituting the reinforcing cord provided on the belt are adhered by a filled rubber filled between the metal wires. That is, the filled rubber functions as an adhesive member for adhering a plurality of metal strands.

Here, a thermoplastic resin may be used as an adhesive resin as an adhesive member for adhering a plurality of metal wires. In this case, when the molten resin is filled between the plurality of twisted metal wires from the outside, the resin is filled to the central portion of the plurality of metal wires through the gaps between the narrow metal wires. There must be. Therefore, the filling pressure varies, and a hollow portion in which the adhesive resin does not exist may be formed inside the reinforcing cord.

An object of the present disclosure is that, as compared with the case where the reinforcing cord is formed by filling the molten resin between the plurality of metal strands from the outside, a hollow portion in which the adhesive resin does not exist is generated inside the reinforcing cord. Is to suppress.

The fiber according to the present disclosure is characterized by including a plurality of metal strands and a plurality of resin strands formed of a thermoplastic resin.

According to the above configuration, the fiber includes a plurality of metal strands and a plurality of resin strands formed of a thermoplastic resin. By heating this fiber, the resin wire is melted, and the melted resin forms an adhesive resin for adhering a plurality of metal wires. Then, a reinforcing cord is formed in which a plurality of metal strands are bonded by an adhesive resin.

In this way, a reinforcing cord is formed by forming an adhesive resin that adheres a plurality of metal wires by melting the resin wires constituting the fiber. Therefore, as compared with the case where the reinforcing cord is formed by filling the molten resin between the plurality of metal strands from the outside, it is possible to suppress the formation of a hollow portion in which the adhesive resin does not exist inside the reinforcing cord. be able to.

According to the fibers according to the present disclosure, there is a hollow portion in which no adhesive resin is present inside the reinforcing cord, as compared with the case where the reinforcing cord is formed by filling the molten resin between the plurality of metal strands from the outside. It can be suppressed from occurring.

It is a half cross-sectional view which shows the state which cut the pneumatic tire manufactured by the manufacturing method of the pneumatic tire which concerns on embodiment of this disclosure along the tire width direction and the tire radial direction. It is sectional drawing which shows the structure of the belt in the pneumatic tire manufactured by the manufacturing method of the pneumatic tire which concerns on embodiment of this disclosure. It is a perspective view which shows the structure of the belt in the pneumatic tire manufactured by the manufacturing method of the pneumatic tire which concerns on embodiment of this disclosure. It is a perspective view which showed the fiber which concerns on embodiment of this disclosure. It is a process drawing used for explaining the manufacturing method of the resin coating cord which concerns on embodiment of this disclosure. It is a process drawing used for explaining the manufacturing method of manufacturing a belt using the resin coating cord manufactured by the manufacturing method of the resin coating cord which concerns on embodiment of this disclosure. (A) (B) is a cross-sectional view showing a reinforcing cord formed by using the fiber according to the embodiment of the present disclosure and a reinforcing cord formed by using the fiber according to the comparative embodiment, respectively. It is a perspective view which showed the fiber which concerns on the comparative embodiment with respect to the embodiment of this disclosure. It is a process drawing used for explaining the manufacturing method of the resin coating cord which concerns on the comparative embodiment with respect to the embodiment of this disclosure.

An example of a method for manufacturing a fiber, a resin-coated cord, and a method for manufacturing a pneumatic tire according to the embodiment of the present disclosure will be described with reference to FIGS. 1 to 9. The arrow W shown in the figure indicates the tire width direction (hereinafter, “tire width direction”), and the arrow R indicates the tire radial direction (hereinafter, “tire radial direction”). Here, the tire width direction is a direction parallel to the tire rotation axis, and the tire radial direction is a direction orthogonal to the tire rotation axis. Further, the reference numeral CL indicates the equatorial plane of the tire 10 (hereinafter, “tire equatorial plane”).

(Overall configuration of tire 10)
The pneumatic tire 10 of the present embodiment is, for example, a so-called radial tire used in a passenger car, and as shown in FIG. 1, includes a pair of bead portions 20 in which a bead core 12 is embedded, and one bead portion 20 and the other. A carcass 16 composed of one carcass ply 14 straddles the bead portion 20 in a toroid shape. Further, the pneumatic tire 10 includes a belt 26 provided on the outer side of the carcass 16 in the tire radial direction and a tread 36 provided on the outer side of the belt 26 in the tire radial direction. Note that FIG. 1 shows the shape of the pneumatic tire 10 in a natural state before being filled with air.

[Carcus Ply 14]
The carcass ply 14 is formed by coating a plurality of cords (not shown) extending in the radial direction of the pneumatic tire 10 with coated rubber (not shown). That is, the pneumatic tire 10 of the present embodiment is a so-called radial tire. The material of the cord of the carcass ply 14 is, for example, PET, but other conventionally known materials may be used.

The end portion of the carcass ply 14 in the tire width direction is folded outward in the tire radial direction so as to surround the bead core 12. In the carcass ply 14, the portion extending from one bead core 12 to the other bead core 12 is referred to as a main body portion 14a, and the portion folded back from the bead core 12 is referred to as a folded portion 14b.

[Bead Filler 18]
A bead filler 18 whose thickness gradually decreases from the bead core 12 toward the outside in the tire radial direction is arranged between the main body portion 14a and the folded-back portion 14b of the carcass ply 14. In the pneumatic tire 10, the bead portion 20 is formed from the outer end 18a of the bead filler 18 in the tire radial direction to the inner portion in the tire radial direction.

[Inner liner 22, side rubber layer 24]
An inner liner 22 made of rubber is arranged inside the carcass 16 in the tire width direction, and a side rubber layer 24 made of a first rubber material is arranged outside the carcass 16 in the tire width direction.

In the present embodiment, the tire case 25 is composed of the bead core 12, the carcass 16, the bead filler 18, the inner liner 22, and the side rubber layer 24. That is, the tire case 25 is a tire skeleton member forming the skeleton of the pneumatic tire 10.

[Belt 26]
A belt 26 is arranged on the outside of the carcass 16 in the tire radial direction (so-called “outside of the crown portion”), and the belt 26 is in close contact with the outer peripheral surface of the carcass 16.

As shown in FIGS. 2 and 3, the belt 26 is formed by winding a resin-coated cord 34 having a substantially parallel quadrilateral cross section in which two reinforcing cords 30 are coated with a coating resin 32 in the tire circumferential direction. ing. The fiber 304 used for forming the reinforcing cord 30, the manufacturing method for manufacturing the resin-coated cord 34 including the reinforcing cord 30, and the manufacturing method for the pneumatic tire including the resin-coated cord 34 will be described later.

It is preferable to use the reinforcing cord 30 of the belt 26 which is thicker than the cord of the carcass ply 14 and has a large strength (tensile strength). The reinforcing cord 30 of the belt 26 is formed by forming a metal wire 300 made of a plurality of metals and an adhesive resin 310 which is a thermoplastic resin filled between the metal wires 300 and for adhering the metal wires 300. It is formed by including.

As the coating resin 32 that coats the reinforcing cord 30, a resin material having a higher tensile elastic modulus than the rubber constituting the side rubber layer 24 and the second rubber material constituting the tread 36 described later is used. As the coating resin 32 that coats the reinforcing cord 30, an elastic thermoplastic resin, a thermoplastic elastomer (TPE), or the like can be used. Considering the elasticity during running and the moldability during manufacturing, it is desirable to use a thermoplastic elastomer.

Examples of the thermoplastic elastomer include polyolefin-based thermoplastic elastomer (TPO), polystyrene-based thermoplastic elastomer (TPS), polyamide-based thermoplastic elastomer (TPA), polyurethane-based thermoplastic elastomer (TPU), and polyester-based thermoplastic elastomer (TPC). , Dynamic cross-linked thermoplastic elastomer (TPV) and the like.

Examples of the thermoplastic resin include polyurethane resin, polyolefin resin, vinyl chloride resin, and polyamide resin. Further, as the thermoplastic resin material, for example, the deflection temperature under load (at 0.45 [MPa] load) specified in ISO75-2 or ASTM D648 is 78 [° C] or more, and the tension specified in JIS K7113. The yield strength is 10 [MPa] or more, the tensile fracture elongation specified in JIS K7113 is 50% or more, and the deflection temperature (A method) specified in JIS K7206 is 130 [° C] or more. be able to.

The tensile elastic modulus (specified in JIS K7113: 1995) of the coating resin 32 that coats the reinforcing cord 30 is preferably 100 [MPa] or more. Further, the upper limit of the tensile elastic modulus of the coating resin 32 covering the reinforcing cord 30 is preferably 1000 [MPa] or less. The tensile elastic modulus of the coating resin 32 that coats the reinforcing cord 30 is particularly preferably in the range of 200 to 700 [MPa].
Further, the in-plane shear rigidity of the belt 26 is preferably equal to or higher than that of the belt formed of the rubber coating.

The thickness dimension t of the belt 26 of the present embodiment is preferably larger than the diameter dimension of the reinforcing cord 30, in other words, it is preferable that the reinforcing cord 30 is completely embedded in the coating resin 32. When the pneumatic tire 10 is for a passenger car, the thickness dimension t of the belt 26 is preferably 0.70 [mm] or more.

[Tread 36]
As shown in FIG. 1, a tread 36 made of a second rubber material is arranged outside the belt 26 in the tire radial direction. As the second rubber material used for the tread 36, a conventionally known material is used. A drainage groove 37 is formed in the tread 36. Further, as the pattern of the tread 36, a conventionally known pattern is used.

The width BW of the belt 26 measured along the tire width direction is preferably 75% or more of the ground contact width TW of the tread 36 measured along the tire width direction. The upper limit of the width BW of the belt 26 is preferably 110% with respect to the ground contact width TW.

Here, the ground contact width TW of the tread 36 means that the pneumatic tire 10 is attached to the standard rim specified in JATMA YEAR BOOK (2019 version, Japan Automobile Tire Association standard), and the applicable size in JATMA YEAR BOOK. The internal pressure is 100% of the air pressure (maximum air pressure) corresponding to the maximum load capacity (internal pressure-load capacity correspondence table in bold) in the ply rating, and the rotation axis becomes parallel to the horizontal flat plate in a stationary state. It is the one when the mass corresponding to the maximum load capacity is added. If the TRA standard or ETRTO standard is applied at the place of use or manufacturing, the respective standards will be followed.

(Main part)
[Manufacturing method of resin coated cord]
Next, the manufacturing method of the resin-coated cord 34 will be described while comparing with the manufacturing method of the resin-coated cord 534 according to the comparative form.

In the method for manufacturing the resin-coated cord 534 according to the comparative form, the fiber 504 in which a plurality of metal strands 300 (so-called "steel cord") are twisted as shown in FIG. 8 is used. As an example, the diameter of the metal wire 300 is 0.3 [mm] or more and 0.5 [mm]. Then, the resin coating cord 534 is manufactured by extrusion molding using the base 510 shown in FIG.

Specifically, as shown in FIG. 9, the fiber 504 is inserted into the base 510 in the direction of arrow A. Then, the molten resin 312 to be the adhesive resin 310 is filled inside the base 510 from the outer peripheral surface side of the fiber 504 (from the outside) into the inside of the fiber 504.

Further, the molten resin 332 to be the coating resin 32 is coated on the fiber 504 inside the base 510, and the fiber 504 is cooled to produce the resin coating cord 534 according to the comparative form. Here, in the resin coating cord 534 according to the comparative embodiment, the molten resin 312 to be the adhesive resin 310 is filled between the metal strands 300 from the outer peripheral surface side of the fiber 504. As a result, as shown in FIG. 7B, a reinforcing cord 530 in which a plurality of metal strands 300 are bonded by an adhesive resin 310 is formed. Here, the filling pressure of the resin 312 varies, and a hollow portion in which the adhesive resin 310 does not exist may be formed inside the reinforcing cord 530.

On the other hand, in the method for manufacturing the resin-coated cord 34 according to the present embodiment, the plurality of metal wire 300 and the plurality of resin wires 302 formed of the thermoplastic resin, as shown in FIG. 4, are twisted. Fiber 304 is used. In other words, the fiber 304 is formed of a plurality of types of strands including the resin strand 302. In the present embodiment, the outer diameter of the resin wire 302 is smaller than the outer diameter of the metal wire 300, and the number of resin wires 302 is larger than the number of the metal wires 300. .. Further, at least two resin wires 302 are in contact with all the metal wires 300 on the cut surface cut in the direction orthogonal to the longitudinal direction. Then, the resin-coated cord 34 is manufactured by extrusion molding using the base 410 shown in FIG.

Specifically, as shown in FIG. 5, the fiber 304 is conveyed in the direction of arrow A and the fiber 304 is heated before being inserted into the mouthpiece 410 (heating step). By melting the resin wire 302 (see FIG. 4) constituting the fiber 304 by this heating, the reinforcing cord 30 including the metal wire 300 and the adhesive resin 310 (see FIG. 7 (A)). Is formed. Further, the reinforcing cord 30 is inserted into the base 410, and the molten resin 332 that becomes the coating resin 32 is coated on the reinforcing cord 30 inside the base 410 (coating step), and this is cooled to form the resin coating cord 34. Manufactured.

Here, in the resin coating cord 34, the adhesive resin 310 is filled between the metal strands 300 by melting the resin strands 302 twisted in advance in the fibers 304. Therefore, as shown in FIG. 7A, the formation of a hollow portion in which the adhesive resin 310 does not exist is suppressed inside the reinforcing cord 30 as compared with the reinforcing cord 530.

The adhesive resin 310 and the resin wire 302 are made of a resin that is more difficult for water to permeate than the resin material used for the coating resin 32, in other words, a resin that is harder to absorb water. Examples of the adhesive constituting the resin material used for the adhesive resin 310 and the resin wire 302 include a modified olefin resin (modified polyethylene resin, modified polypropylene resin, etc.), polyamide resin, polyurethane resin, and polyester resin. Examples thereof include those containing one or more thermoplastic resins such as resins, modified polyester resins, ethylene-ethyl acrylate copolymers, and ethylene-vinyl acetate copolymers as the main component (main agent).

Among these, from the viewpoint of adhesiveness to the metal member (metal wire 300) and the resin layer (coating resin 32), a modified olefin resin, a polyester resin, a modified polyester resin, and an ethylene-ethyl acrylate copolymer , And a hot melt adhesive containing at least one selected from the group consisting of an ethylene-vinyl acetate copolymer is preferable, and a hot melt adhesive containing at least one selected from a modified olefin resin and a modified polyester resin is more preferable. Among them, a hot melt adhesive containing at least one selected from an acid-modified olefin resin (modified olefin resin acid-modified with an unsaturated carboxylic acid) and a modified polyester resin is more preferable, and an acid-modified polyester resin is more preferable. A hot melt adhesive containing is particularly preferable.

Here, the "modified olefin resin acid-modified with an unsaturated carboxylic acid" means a modified olefin resin obtained by graft-copolymerizing an unsaturated carboxylic acid with a polyolefin.

[Manufacturing method of pneumatic tires]
Next, an example of the method for manufacturing the pneumatic tire 10 of the present embodiment will be described.

First, an unvulcanized unvulcanized outer liner 22 made of a rubber material, a bead core 12, a bead filler 18, a carcass ply 14 whose cord is coated with a rubber material, and a side rubber layer 24 are formed on the outer periphery of a known tire forming drum (not shown). Tire case 25 is formed (see FIG. 1). The manufacturing method up to this point is the same as before.

On the other hand, the belt 26 is formed by spirally winding a resin-coated cord 34 having a substantially parallel quadrilateral cross section around a belt forming drum 400 having a circular cross section.

An example of the manufacturing process of the belt 26 will be described below with reference to FIG. First, the cord supply device 420, the heating device 450, the pressing roller 460, and the cooling roller 470 are movably arranged in the vicinity of the belt forming drum 400.

The cord supply device 420 includes a reel 430 around which the resin-coated cord 34 is wound, and a guide member 440 for guiding the resin-coated cord 34 unwound from the reel 430 to the outer periphery of the belt forming drum 400. ing. The guide member 440 has a tubular shape, and the resin coating cord 34 passes through the inside. Further, the resin coating cord 34 is sent out from the mouth portion 440a of the guide member 440 toward the outer peripheral surface of the belt forming drum 400.

The heating device 450 blows hot air onto the resin-coated cord 34 to heat and melt the blown portion. In the present embodiment, the air heated by the heating wire (not shown) is blown out from the outlet 450a by the air flow generated by the fan (not shown), and the blown out hot air is blown to the resin coating cord 34. ing. The configuration of the heating device 450 is not limited to the above configuration, and may be any configuration as long as the thermoplastic resin can be heated and melted. For example, the side surface of the resin coating cord 34 may be brought into contact with a hot iron to heat and melt the side surface, the side surface may be heated and melted by radiant heat, or infrared rays may be irradiated to heat and melt the side surface.

The pressing roller 460 presses the resin coating cord 34 against the outer peripheral surface of the belt forming drum 400, and the pressing force F can be adjusted. Further, the roller surface of the pressing roller 460 is processed to prevent the resin material in a molten state from adhering to the roller surface. The pressing roller 460 is rotatable, and when the resin coating cord 34 is pressed against the outer periphery of the belt forming drum 400, the pressing roller 460 is driven to rotate with respect to the belt forming drum 400 rotating in the arrow B direction. It has become.

Further, the cooling roller 470 is arranged downstream of the pressing roller 460 in the rotation direction of the belt forming drum 400, and cools the resin coating cord 34 while pressing the resin coating cord 34 against the outer peripheral surface of the belt forming drum 400. Is. Like the pressing roller 460, the cooling roller 470 is processed so that the pressing force can be adjusted and the surface of the roller is prevented from adhering to the molten resin material. Further, the cooling roller 470 is rotatable like the pressing roller 460, and when the resin coating cord 34 is pressed against the outer peripheral surface of the belt forming drum 400, the belt forming drum 400 rotates in the arrow B direction. It is designed to rotate in a driven manner.

Further, in the cooling roller 470, a liquid (for example, water or the like) circulates inside the roller, and a member (resin coating cord 34 in the present embodiment) or the like that comes into contact with the roller surface by heat exchange of the liquid or the like. Can be cooled. When the molten resin material is naturally cooled, the cooling roller 470 may be omitted.

Then, the belt forming drum 400 is rotated in the direction of arrow B, and the resin coating cord 34 is sent out from the mouth portion 440a of the cord supply device 420 toward the outer peripheral surface of the belt forming drum 400.

Then, hot air is blown from the outlet 450a of the heating device 450 toward the resin coating cord 34 to heat the resin coating cord 34 while melting the surface of the coating resin 32 and adhering the resin coating cord 34 to the belt forming drum 400. 34 is pressed against the outer peripheral surface of the belt forming drum 400 by the pressing roller 460. The pressing roller 460 deforms the resin coating cord 34 so that the side portions bulge in the tire width direction (deformation due to crushing), and the side surfaces of the coating resin 32 adjacent to each other in the tire width direction are brought into contact with each other and welded. To do.

After that, the molten portion of the coating resin 32 comes into contact with the cooling roller 470 and is solidified, and welding of the adjacent resin coating cords 34 is completed.

In this way, the resin coating cord 34 is spirally wound around the outer peripheral surface of the belt forming drum 400 and pressed against the outer peripheral surface to form the belt 26 on the outer peripheral surface of the belt forming drum 400. In order to wind the resin-coated cord 34 in a spiral shape, the position of the mouth portion 440a of the cord supply device 420 may be moved in the tire width direction with the rotation of the belt forming drum 400, or the belt forming drum 400 may be moved in the tire width direction. You can move it in the direction.

Next, the belt 26 in which the coating resin 32 is solidified is removed from the belt forming drum 400, placed outside the tire case 25 (see FIG. 1) in the radial direction, and the tire case 25 is expanded to cover the outer peripheral surface of the tire case 25. In other words, the outer peripheral surface of the carcass 16 is crimped to the inner peripheral surface of the belt 26. Finally, the unvulcanized tread 36 is attached to the outer peripheral surface of the belt 26 to complete the raw tire.

The raw tire produced in this way is vulcanized by a vulcanization molding mold to complete the pneumatic tire 10.

(Action, effect)
Next, the actions and effects of the fiber 304, the method for manufacturing the resin-coated cord, and the method for manufacturing the pneumatic tire will be described.

The fiber 304 according to the present embodiment includes a plurality of metal wire 300 and a resin wire 302 formed of a plurality of thermoplastic resins. Therefore, as compared with the case where the reinforcing cord 30 is formed by using the fiber 304, the reinforcing cord 530 is formed by filling the inside of the fiber 504 with resin from the outer peripheral surface side of the fiber 504 (from the outside). Therefore, it is possible to suppress the formation of a hollow portion in which the adhesive resin 310 does not exist inside the reinforcing cord 30.

Further, in the fiber 304, at least two resin wires 302 are in contact with all the metal wires 300 on the cut surface cut in the direction orthogonal to the longitudinal direction. Therefore, as compared with the case where at least two resin wires 302 are not in contact with all the metal wires 300, the molten resin surrounds the metal wires 300, so that the adhesive resin is inside the reinforcing cord 30. It is possible to suppress the formation of a hollow portion in which 310 does not exist.

Further, in the fiber 304, the plurality of metal strands 300 and the plurality of resin strands 302 are in a twisted state. Therefore, it is possible to prevent the metal wire 300 and the resin wire 302 from being separated from each other as compared with the case where they are not twisted.

Further, in the method for manufacturing the resin-coated cord, the resin-coated cord 34 is manufactured using the fiber 304. Therefore, it is possible to prevent the formation of a hollow portion in which the adhesive resin 310 does not exist inside the reinforcing cord 30 constituting the resin-coated cord 34 manufactured by the method for manufacturing the resin-coated cord. Thereby, for example, when a repeated load in the tensile direction is applied to the resin coating cord 34, it is possible to prevent peeling from occurring between the metal wire 300 and the adhesive resin 310.

Further, in the method for manufacturing a pneumatic tire, the pneumatic tire 10 is manufactured by using the belt 26 formed by the resin-coated cord 34. Therefore, in the tire 10 manufactured by the method for manufacturing a pneumatic tire, it is possible to improve the fatigue durability performance in which a particularly high load is repeatedly applied to the tire 10.

Although the present disclosure has been described in detail for a specific embodiment, the present disclosure is not limited to such an embodiment, and various other embodiments are possible within the scope of the present disclosure. It is obvious to the trader. For example, in the above embodiment, the resin wire 302 is melted by heating the fiber 304 (so-called “preheating”) before being inserted into the mouthpiece 410, but the resin wire is inside the mouthpiece 410. 302 may be melted. That is, the heating step and the coating step may be performed inside the base 410.

Further, in the fiber 304 of the above embodiment, at least two resin wires 302 are in contact with the metal wire 300 on the cut surface cut in the direction orthogonal to the longitudinal direction, but one metal wire is used. At least two resin strands 302 may come into contact with the wire 300. As a result, it is possible to suppress the formation of a hollow portion in which the adhesive resin 310 does not exist inside the reinforcing cord 30, as compared with the case where only one resin wire 302 is in contact with one metal wire 300. Can be done.

Further, in the fiber 304 of the above embodiment, the plurality of metal wires 300 and the plurality of resin wires 302 are in a twisted state, but they do not have to be twisted. However, in this case, the effect of twisting does not work.

The disclosure of Japanese Patent Application No. 2019-20259, filed December 5, 2019, is incorporated herein by reference in its entirety.
All documents, patent applications, and technical standards described herein are to the same extent as if the individual documents, patent applications, and technical standards were specifically and individually stated to be incorporated by reference. Incorporated herein by reference.

Claims

With multiple metal wires,
Multiple resin wires made of thermoplastic resin,
Fiber with.
The fiber according to claim 1, wherein at least two resin wires are in contact with one metal wire on a cut surface cut in a direction orthogonal to the longitudinal direction.
The fiber according to claim 2, wherein at least two resin wires are in contact with all the metal wires on a cut surface cut in a direction orthogonal to the longitudinal direction.
The fiber according to any one of claims 1 to 3, wherein the plurality of the metal strands and the plurality of resin strands are in a twisted state.
The fiber according to any one of claims 1 to 4 is heated to melt the resin wire to form a plurality of the metal wires as an adhesive resin, and reinforcement including the plurality of the metal wires and the adhesive resin. The heating process to form the cord and
A coating step of coating the reinforcing cord with another thermoplastic resin different from the resin forming the resin wire to form a coating resin, and
A method for manufacturing a resin-coated cord.
The process of forming an unvulcanized tire case consisting of an inner liner, bead core, bead filler, carcass ply, and side rubber layer,
A step of forming a belt by spirally winding the resin-coated cord manufactured by the method for manufacturing a resin-coated cord according to claim 5 around the outer peripheral surface of a belt forming drum while heating it and pressing it against the outer peripheral surface.
A step of arranging the belt on the outer side in the radial direction of the tire case, expanding the tire case, and crimping the inner peripheral surface of the belt to the outer peripheral surface of the tire case.
A step of vulcanizing and molding by attaching an unvulcanized tread to the outer peripheral surface of the belt crimped to the outer peripheral surface of the tire case.
A method of manufacturing a pneumatic tire.