Metal cord, composite cord, cord-rubber composite, and rubber product

Abstract

Provided is a metal cord for reinforcing rubber in which the metal cord is disposed, the metal cord having a gap part and a metal plate-shaped body arranged so as to surround at least a part of the gap part in a cross section perpendicular to the longitudinal direction.

Description

Metal cords, composite cords, cord-rubber composites, rubber products

[0001] The present disclosure relates to metal cords, composite cords, cord-rubber composites, and rubber products.

[0002] This application claims priority based on Japanese Application No. 2024-103279 filed on June 26, 2024, and incorporates by reference all of the contents of said Japanese application.

[0003] Patent Document 1 discloses a steel cord for reinforcing rubber products, characterized in that the cord is formed into a substantially two-dimensional waveform by twisting together a plurality of copper alloy or zinc-plated steel filaments having a wire diameter of 0.05 to 0.45 mm at a twist pitch of 8 to 15 mm, and the amplitude from one peak to the next peak of this waveform is 30 to 80% of the twist pitch, and the wavelength of the waveform is 230 to 400% of the amplitude.

[0004] Japanese Unexamined Patent Publication No. 1-006187

[0005] The metal cord of the present disclosure is a metal cord that is placed within rubber to reinforce the rubber, and in a cross section perpendicular to the longitudinal direction, has a void portion and a metal plate-like body that is arranged to surround at least a portion of the void portion.

[0006] FIG. 1A is a cross-sectional view of a metal cord according to one embodiment of the present disclosure. FIG. 1B is a cross-sectional view of a metal cord according to one embodiment of the present disclosure. FIG. 1C is a cross-sectional view of a metal cord according to one embodiment of the present disclosure. FIG. 1D is a cross-sectional view of a metal cord according to one embodiment of the present disclosure. FIG. 1E is a cross-sectional view of a metal cord according to one embodiment of the present disclosure. FIG. 2A is a cross-sectional view of a metal cord according to one embodiment of the present disclosure. FIG. 2B is a cross-sectional view of a metal cord according to one embodiment of the present disclosure. FIG. 2C is a cross-sectional view of a metal cord according to one embodiment of the present disclosure. FIG. 2D is a cross-sectional view of a metal cord according to one embodiment of the present disclosure. FIG. 2E is a cross-sectional view of a metal cord according to one embodiment of the present disclosure. FIG. 2F is a cross-sectional view of a metal cord according to one embodiment of the present disclosure. FIG. 3A is an explanatory diagram of an example configuration of a plate-shaped body. FIG. 3B is an explanatory diagram of an example configuration of a plate-shaped body. FIG. 3C is an explanatory diagram of an example configuration of a plate-shaped body. FIG. 4 is a perspective view of the metal cord shown in FIG. 1B. FIG. 5 is an explanatory diagram of an example configuration of a twisted metal cord. FIG. 6 is an explanatory diagram of a composite cord according to one embodiment of the present disclosure. 7 is an illustration of a cord-rubber composite according to one embodiment of the present disclosure, and FIG. 8 is an illustration of a rubber product according to one embodiment of the present disclosure.

[0007] [Problem to be solved by the present disclosure]

[0008] Metal cords have been considered for reinforcing rubber products.

[0009] Known metal cords include steel cords formed by twisting together a plurality of steel filaments, as disclosed in, for example, Patent Document 1.

[0010] In recent years, the types of rubber products using cord-rubber composites have become more diverse, and there has been a demand for new metal cords that differ from conventional ones so that an optimum cord can be selected for use in cord-rubber composites depending on the application, etc.

[0011] Therefore, an object of the present disclosure is to provide a novel metal cord that can be used as a reinforcing material for rubber.

[0012] [Effects of the present disclosure]

[0013] According to the present disclosure, a novel metal cord that can be used as a reinforcing material for rubber can be provided.

[0014] [Description of the embodiments of the present disclosure] First, the embodiments of the present disclosure will be listed and described. In the following description, the same or corresponding elements will be denoted by the same reference numerals, and the same description will not be repeated.

[0015] (1) A metal cord according to one aspect of the present disclosure is a metal cord that is disposed within rubber to reinforce the rubber, and in a cross section perpendicular to the longitudinal direction, has a void portion and a metal plate-like body that is disposed so as to surround at least a portion of the void portion.

[0016] The metal cord according to one embodiment of the present disclosure has voids, which makes it possible to reduce the weight of the metal cord compared to a cord without voids, thereby enabling cord-rubber composites and rubber products including the metal cord according to one embodiment of the present disclosure to be lightweight.

[0017] By having voids in the metal cord according to one embodiment of the present disclosure, it is possible to fill the voids with a filler such as rubber or resin, making it easier to control properties such as strength and adhesion to rubber.

[0018] Since the metal cord according to one embodiment of the present disclosure has a metal plate-shaped body, the cross-sectional shape perpendicular to the longitudinal direction of the metal cord can be easily selected by stretching or bending the metal plate.

[0019] (2) In (1), the plate-like body may have an opening in the cross section that is connected to the gap.

[0020] The openings in the plate allow the rubber to penetrate into the gaps when the metal cord is placed inside the rubber. This increases the contact area between the metal cord and the rubber, improving adhesion. Furthermore, the area of ​​the metal cord surface covered by the rubber can be increased, preventing corrosion and other problems on the metal cord surface.

[0021] (3) In (2), the plate-like body may have two or more openings in the cross section.

[0022] The greater the number of openings the plate-like body has, the easier it is to increase the filling rate of the rubber in the voids when the metal cord is disposed in the rubber.

[0023] (4) In (1), the entire outer periphery of the gap in the cross section may be covered by the plate-like body.

[0024] By covering the entire outer periphery of the gap with the plate-like body, the gap can be left hollow, making it possible to reduce the weight of the cord-rubber composite containing the metal cord and the rubber product.

[0025] (5) In any one of (1) to (4), a filler may be further disposed in the void.

[0026] The metal cord according to one embodiment of the present disclosure has a filler disposed in the voids, which prevents the metal cord from being damaged when an external force is applied to the metal cord. Furthermore, the metal cord has a filler such as resin or rubber in the voids, which allows the metal cord to be lighter than when the voids are filled with a metal such as steel. This allows the metal cord, cord-rubber composites containing the metal cord, and rubber products to be lighter.

[0027] By disposing a filler in the gap, the exposed surface area of ​​the metal cord can be reduced, and rust and the like can be prevented from occurring on the metal cord.

[0028] (6) In any one of (1) to (5), the plate-like body may have a wave-like shape having concave portions and convex portions alternately arranged along the length.

[0029] The corrugated shape of the plate-like body makes it easier for the plate-like body and the metal cord to expand and contract along the length when force is applied to the metal cord along the length, etc. Therefore, even when force is applied to the metal cord along the length, the metal cord can be prevented from being damaged.

[0030] (7) In any one of (1) to (6), the plate-like body may include a curved portion in the cross section.

[0031] By including the curved portion in the plate-like body, the metal cord can be made less likely to deform and be damaged when an external force is applied to the metal cord.

[0032] (8) In any one of (1) to (7), the plate-shaped body may include at least a first plate-shaped body and a second plate-shaped body.

[0033] When the metal cord has a plurality of plate-like bodies, the plate-like bodies can be formed into a predetermined shape and then combined to produce a metal cord having a desired cross-sectional shape. Therefore, when the metal cord has a plurality of plate-like bodies, the productivity of the metal cord can be increased.

[0034] (9) In any one of (1) to (8), the diameter of the smallest encompassing circle of the metal cord in the cross section may be 0.10 mm or more and 0.45 mm or less.

[0035] By setting the cord diameter, which is the diameter of the smallest encompassing circle of the metal cord in a cross section perpendicular to the longitudinal direction of the metal cord, to 0.10 mm or more, the tensile strength of the metal cord can be sufficiently increased. By setting the cord diameter to 0.45 mm or less, when the metal cord is placed inside rubber to form a cord-rubber composite, the thickness of the cord-rubber composite can be reduced, and the cord-rubber composite and rubber products can be made lighter.

[0036] (10) In any one of (1) to (9), the metal of the plate-shaped body may include high carbon steel.

[0037] By including high carbon steel in the metal of the plate-shaped body, the tensile strength of the plate-shaped body and the metal cord can be increased.

[0038] (11) In any one of (1) to (10), the plate-shaped body may have a brass plating film on its surface.

[0039] By providing the plate-shaped body with a brass plating film on the surface, when a metal cord is placed inside the rubber, the initial adhesive performance between the metal cord and the rubber can be improved.

[0040] (12) In any of (1) to (11), the wire may be twisted spirally along its longitudinal direction.

[0041] By twisting the metal cord in a spiral shape along its length, the metal cord can easily expand and contract along its length when force is applied to the metal cord along its length, which prevents the metal cord from being damaged even when force is applied to the metal cord along its length.

[0042] The metal cord is twisted spirally along its length, creating an uneven surface, which increases the contact area between the metal cord and rubber when the metal cord is placed inside the rubber, improving adhesion between the two components.

[0043] Furthermore, when the metal cord includes a plurality of plate-like bodies or a filler, the metal cord is twisted spirally along its length, thereby increasing the bonding strength between the plurality of members.

[0044] (13) A composite cord according to one aspect of the present disclosure is a twisted wire of a plurality of metal cords according to any one of (1) to (12).

[0045] By forming a composite cord, which is a twisted wire made by twisting together multiple metal cords, it is possible to use the cord-rubber composite or rubber product and make it easier for the composite cord to stretch along the length when force is applied along the length of the composite cord, which makes the cord-rubber composite or rubber product less susceptible to damage and increases its durability.

[0046] (14) A cord-rubber composite according to one aspect of the present disclosure includes rubber and the metal cord according to any one of (1) to (12) disposed within the rubber.

[0047] The metal cord has voids inside, so it can be made lighter than a cord without voids, and therefore the cord-rubber composite according to one embodiment of the present disclosure, which includes the metal cord, and rubber products can be made lighter.

[0048] (15) A rubber product according to one aspect of the present disclosure includes the cord-rubber composite material according to (14).

[0049] Since the metal cord has voids inside, it can be made lighter than a cord without voids, and therefore the rubber product of this embodiment including the metal cord can be made lighter.

[0050] [Details of the embodiment of the present disclosure] Specific examples of a metal cord, composite cord, cord-rubber composite, and rubber product according to one embodiment of the present disclosure (hereinafter referred to as "the present embodiment") will be described below with reference to the drawings. The present invention is not limited to these examples, but is defined by the claims, and is intended to include all modifications within the meaning and scope equivalent to the claims. [Metal cord] The metal cord according to this embodiment will be described below with reference to the drawings.

[0051] 1A to 1E are cross-sectional views of the metal cord of this embodiment taken along a plane perpendicular to the longitudinal direction, and FIGS. 2A to 2F are cross-sectional views of the metal cord of this embodiment taken along a plane perpendicular to the longitudinal direction when a filler is included.

[0052] 3A, 3B, and 3C are explanatory diagrams of modified examples of the metal plate-shaped body of the metal cord of this embodiment.

[0053] FIG. 4 is a perspective view of the metal cord of this embodiment, which is a perspective view of the metal cord 10B shown in FIG. 1B.

[0054] FIG. 5 is an explanatory diagram of the metal cord of this embodiment when it is twisted.

[0055] FIG. 6 is an explanatory diagram of a composite cord formed by twisting together a plurality of metal cords according to this embodiment.

[0056] The Y axis in Figures 1A to 1E, 2A to 2F, 3A to 3C, 4, and 5 (hereinafter, when these figures are collectively shown, they will be expressed as "Figures 1A to 5") is an axis along the longitudinal direction of the metal cord 10. Also, the XZ plane in Figures 1A to 5 is a plane perpendicular to the longitudinal direction of the metal cord 10.

[0057] The metal cord of this embodiment is disposed within rubber and can be used to reinforce the rubber.

[0058] The metal cord 10 of this embodiment can have a void portion 11 and a metal plate-like body 12 arranged to surround at least a portion of the void portion 11, for example, as shown in FIG. 1A.

[0059] The metal cord 10 of this embodiment has the voids 11, and therefore can be made lighter than a cord not having the voids 11. Therefore, a cord-rubber composite including the metal cord 10 of this embodiment and a rubber product can be made lighter.

[0060] The metal cord 10 of this embodiment has voids 11, which can be filled with a filler such as rubber or resin, making it easier to control properties such as strength and adhesion to rubber. Thus, the voids 11 refer to regions in a cross section perpendicular to the longitudinal direction that are at least partially surrounded by the metal plate-like body 12 and in which no metal such as steel is disposed, and the voids 11 may be filled with a filler that is a material other than metal.

[0061] The metal cord 10 of this embodiment has the metal plate 12, and the cross-sectional shape perpendicular to the longitudinal direction of the metal cord 10 can be easily selected by stretching or bending the plate 12. (1) Cross-sectional shape of the metal cord (1-1) In the case of a circular cross section The cross-sectional shape perpendicular to the longitudinal direction of the metal cord 10 of this embodiment is not particularly limited, and can have any shape.

[0062] For example, as shown in FIG. 1A, the cross section perpendicular to the longitudinal direction of the metal cord 10A may be circular. In the metal cord 10A shown in FIG. 1A, the void 11 has a circular shape. The metal plate 12 of the metal cord 10A has a circular shape so as to completely cover the void 11 in the cross section perpendicular to the longitudinal direction of the metal cord 10A. In this specification, the circle is not limited to a perfect circle, but may be any shape surrounded by curves, such as an ellipse, an oval, or a rounded rectangle (track shape). (Opening) Furthermore, as shown in the metal cord 10B shown in FIG. 1B and the metal cord 10C shown in FIG. 1C, the plate 12 may have an opening 13 connected to the void 11 in the cross section perpendicular to the longitudinal direction. The opening 13 is provided to connect the void 11 to an area outside the area surrounded by the plate 12. Therefore, in this case, the gap 11 is surrounded by the plate-like body 12 and the opening 13 that the plate-like body 12 has.

[0063] The openings 13 in the plate-like body 12 allow the rubber to penetrate into the gaps 11 when the metal cord 10 is placed in rubber. This increases the contact area between the metal cord 10 and the rubber, improving adhesion. Furthermore, the area of ​​the surface of the metal cord 10 that is covered with rubber can be increased, preventing corrosion and other problems on the surface of the metal cord 10.

[0064] The number of openings 13 in the plate-like body 12 is not particularly limited. In a cross section perpendicular to the longitudinal direction of the metal cord 10, the plate-like body 12 may have two openings, a first opening 131 and a second opening 132, as in the metal cord 10C shown in Fig. 1C . The plate-like body 12 may also have three or more openings. That is, in a cross section perpendicular to the longitudinal direction of the metal cord 10, the plate-like body 12 may have two or more openings 13.

[0065] The greater the number of openings 13 that the plate-like body 12 has, the easier it is to increase the filling rate of the rubber in the gaps 11 when the metal cord 10 is disposed in the rubber.

[0066] When the plate-like body 12 has openings 13, the arrangement of the openings 13 along the longitudinal direction of the metal cord 10 is not particularly limited. As shown in Figure 4, which is a perspective view of the metal cord 10B shown in Figure 1B, the openings 13 may be arranged linearly along the longitudinal direction of the metal cord 10B. The openings 13 do not need to be continuous along the longitudinal direction of the metal cord 10B as shown in Figure 4, and may be arranged, for example, in a dotted line. Therefore, the number of openings 13 in the plate-like body 12 of the metal cord 10 of this embodiment may vary depending on the position of the cross section perpendicular to the longitudinal direction of the metal cord 10.

[0067] 4, the openings may be arranged in a spiral shape along the length of the metal cord 10. The arrangement of the openings along the length of the metal cord 10 shown in FIG. 4 is merely an example, and the openings may be arranged in a shape other than a linear or spiral shape.

[0068] The metal cord 10 of this embodiment may not have the opening 13. That is, for example, as in the metal cord 10A shown in Fig. 1A , the entire outer periphery of the void portion 11 may be covered by the plate-like body 12 in a cross section perpendicular to the longitudinal direction of the metal cord 10.

[0069] The entire outer periphery of the void 11 is covered by the plate-like body 12, so that the void 11 can remain hollow, and the cord-rubber composite including the metal cord 10 and the rubber product can be made lightweight. (1-2) Shapes Other Than Circular The cross-sectional shape of the metal cord 10 of this embodiment is not limited to a circular shape, and may be a polygonal shape or the like.

[0070] For example, the cross section perpendicular to the longitudinal direction may be triangular, as in the metal cord 10D shown in Fig. 1D. Alternatively, the cross section perpendicular to the longitudinal direction may be quadrangular, as in the metal cord 10E shown in Fig. 1E. Here, the cross section perpendicular to the longitudinal direction of the metal cord 10 is exemplified as being triangular or quadrangular, but the cross section perpendicular to the longitudinal direction of the metal cord 10 may also be pentagonal or polygonal.

[0071] In both the metal cord 10D shown in Fig. 1D and the metal cord 10E shown in Fig. 1E, the plate-like body 12 has an opening 13, but is not limited to this configuration. In a cross section perpendicular to the longitudinal direction of the metal cord 10, the entire outer periphery of the void portion 11 may be covered by the plate-like body 12, or the plate-like body 12 may have two or more openings 13.

[0072] Up to this point, the metal cord 10 has been described as having a circular or polygonal cross section perpendicular to its longitudinal axis. However, the present invention is not limited to such a configuration, and the metal cord 10 may have any cross section perpendicular to its longitudinal axis. (2) Components of the Metal Cord (2-1) Plate-Shaped Body (Number of Plate-Shaped Body in the Metal Cord) The metal cord 10 may also have one metal plate-shaped body 12 as shown in FIGS. 1A and 1B. The metal cord 10A shown in FIG. 1A may be manufactured, for example, by rolling a single metal plate so that the cross section perpendicular to its longitudinal axis is circular and then connecting the plates by welding, crimping, or the like. Note that the metal cord 10A shown in FIG. 1A may also be manufactured by rolling a single metal plate so that the cross section perpendicular to its longitudinal axis is circular, and then partially overlapping the plates without welding, crimping, or the like, thereby eliminating the opening 13.

[0073] The metal cord 10 may also include a plurality of plates 12 .

[0074] For example, as in the metal cords 10C and 10D shown in Figures 1C and 1D, the metal cord 10 may have at least a first plate-like body 121 and a second plate-like body 122. Also, as in the metal cord 10E shown in Figure 1E, the metal cord 10 may have a first plate-like body 121, a second plate-like body 122, and a third plate-like body 123.

[0075] Since the metal cord 10 has a plurality of plate-like bodies 12, the plate-like bodies 12 can be formed into a predetermined shape and combined to produce a metal cord 10 having a desired cross-sectional shape. Therefore, since the metal cord 10 has a plurality of plate-like bodies 12, the productivity of the metal cord 10 can be improved.

[0076] The metal cord 10A shown in Fig. 1A may also have a plurality of plate-like bodies 12. When the metal cord 10A shown in Fig. 1A has a plurality of plate-like bodies 12, the plurality of plate-like bodies 12 may be connected by welding, crimping, or the like.

[0077] 1D and 1E, the plate-like body 12 in the metal cord 10D or 10E can also be manufactured by bending a single metal plate. In this case, the plate-like body of the metal cord 10D or 10E is formed from a single plate-like body. (Shape of the plate-like body in a cross section perpendicular to the longitudinal direction of the metal cord) As shown in FIGS. 1A to 1C, when the metal cord 10 has a shape including a curve, such as a circular shape, in a cross section perpendicular to the longitudinal direction of the metal cord 10, the plate-like body 12 can also include a curved portion 14 in the cross section perpendicular to the longitudinal direction of the metal cord 10.

[0078] By including the curved portion 14 in the plate-like body 12, the metal cord 10 can be made less likely to deform and break when an external force is applied to the metal cord 10.

[0079] As shown in FIGS. 1D and 1E, in a cross section perpendicular to the longitudinal direction of the metal cord 10, the plate-like body 12 may include a linear portion, or may be formed only of a linear portion.

[0080] As in the metal cord 30A, which is a modified example of the metal cord 20F shown in FIG. 3A, the plate-shaped body 12 may be chamfered in a cross section perpendicular to the longitudinal direction of the metal cord 10, to have a chamfered portion 31.

[0081] By providing the chamfered portion 31 on the plate-like body 12, when the metal cord 10 is placed in rubber, the contact area between the rubber and the metal cord 10 can be increased, improving the adhesion between the rubber and the metal cord 10. Furthermore, by providing the chamfered portion 31 on the plate-like body 12, the corners connecting the outer surfaces of the plate-like body 12 can be made obtuse, reducing the number of right-angled or acute-angled corners connecting the outer surfaces of the plate-like body 12 that could be the starting point for cracks in the rubber. Therefore, when the metal cord 10 is placed in rubber, cracks or the like can be prevented from occurring in the rubber. (Shape of the plate-like body along the length of the metal cord) The plate-like body 12 may have a flat plate shape with no irregularities along the length of the metal cord 10.

[0082] Furthermore, the plate-like body 12 may have a wave-like shape in which recesses 32 and protrusions 33 are alternately arranged along the longitudinal direction, as shown in FIG. 3B.

[0083] The corrugated shape of the plate body 12 allows the plate body 12 and the metal cord 10 to easily expand and contract along their length when force is applied to the metal cord 10 along its length. Therefore, even when force is applied to the metal cord 10 along its length, damage to the metal cord 10 can be prevented. The recessed portions 32 refer to portions that are relatively lower along the Z axis in the figure, and the protruding portions 33 refer to portions that are relatively higher along the Z axis in the figure. While FIG. 3B illustrates an example in which the recessed portions 32 and the protruding portions 33 have curved shapes, this is not a limitation. For example, the portion between the recessed portion 32 and the protruding portion 33 can be a non-bent portion, such as a straight line, and the recessed portions 32 and the protruding portions 33 can be bent portions that are corners that change the orientation of the non-bent portion. (Material of the Plate Body) The metal of the plate body 12 may include, for example, steel or high-carbon steel. The plate body 12 may be a steel plate or a high-carbon steel plate.

[0084] When the metal of the plate-shaped body 12 contains steel, it is possible to increase the tensile strength of the plate-shaped body 12 and the metal cord 10. When the metal of the plate-shaped body 12 contains high carbon steel, it is possible to particularly increase the tensile strength of the plate-shaped body 12 and the metal cord 10.

[0085] The plate 12 can also be formed solely from steel. However, this is not limited to this configuration. For example, as shown in FIG. 3C, which is a modified version of the metal cord 20F, the plate 12 can have a brass plating film 35 on the surface of the substrate 34. Specifically, the plate 12 can have a substrate 34 and a brass plating film 35 covering at least a portion of the surface of the substrate 34. The substrate 34 may be made of steel, high-carbon steel, or the like. (Brass Plating Film) The brass plating film 35 can contain copper (Cu) and zinc (Zn). As shown in FIG. 3C, the brass plating film 35 can be disposed so as to include the outer surface of the plate 12 and to cover at least a portion of the outer surface of the substrate 34.

[0086] When the metal cord 10 is placed in rubber to form a cord-rubber composite, the copper contained in the brass plating film 35 reacts with sulfur (S) contained in the rubber. Then, copper sulfide (Cu), which is a reaction product, is generated in the rubber near the interface between the metal cord 10 and the rubber.２ S).

[0087] The adhesive layer thus formed can improve the initial adhesive performance between the metal cord 10 and the rubber. The initial adhesive performance means the adhesive performance between the metal cord 10 and the rubber immediately after vulcanization during the production of a cord-rubber composite or a rubber product containing the cord-rubber composite.

[0088] It is believed that the zinc contained in the brass plating film 35 promotes and controls the reaction that forms the adhesive layer.

[0089] Therefore, by having the brass plating film 35 on the surface of the plate-like body 12, when the metal cord 10 is placed on rubber, the initial adhesive performance between the metal cord 10 and the rubber can be improved.

[0090] The brass plating film 35 may contain elements other than copper and zinc, and may further contain one or more elements selected from the group consisting of cobalt (Co), nickel (Ni), tin (Sn), iron (Fe), and manganese (Mn).

[0091] The additive elements cobalt, nickel, tin, iron, and manganese have a greater tendency to ionize than copper. Therefore, when the brass plating film 35 contains additive elements in addition to copper and zinc, the brass plating film 35 functions as a sacrificial anticorrosion agent or makes the composite potential of copper and zinc more noble. Therefore, the addition of additive elements to the brass plating film 35 can improve the corrosion resistance of the metal cord 10. (2-2) Filler As shown in Figures 2A to 2F, the metal cord 10 of this embodiment can also have fillers 21 disposed in the voids 11.

[0092] The metal cord 10 of this embodiment has the filler 21 disposed in the voids 11, which prevents the metal cord 10 from being damaged when force is applied to the metal cord 10 along the Z-axis, i.e., the axis along the thickness. Furthermore, the metal cord 10 has the filler 21, such as resin or rubber, in the voids 11, which allows the metal cord 10 to be lighter than when the voids 11 are filled with a metal, such as steel. This allows the metal cord 10, as well as cord-rubber composites and rubber products that include the metal cord 10, to be lighter.

[0093] By disposing the filler 21 in the gap 11, the exposed surface area of ​​the metal cord can be reduced, and rust and the like can be prevented from occurring on the metal cord.

[0094] There are no particular limitations on the material of the filler 21, and it may be one or more types selected from, for example, resin and rubber. The material of the filler 21 may be the same rubber as the rubber arranged around the metal cord in the cord-rubber composite, or a different rubber from the rubber used in the cord-rubber composite or various resins.

[0095] The filler 21 may be filled in at least a part of the gap 11, but may also be filled in the entire gap 11.

[0096] As in the metal cord 20A shown in Figure 2A, the metal cord 20B shown in Figure 2B, the metal cord 20C shown in Figure 2C, the metal cord 20D shown in Figure 2D, and the metal cord 20E shown in Figure 2E, the filler 21 can be placed in the gap 11 surrounded by the plate-like body 12.

[0097] 2F, the filler 21 may be disposed so as to connect two plates 12, that is, a first plate 121 and a second plate 122. That is, in the metal cord 20F, the filler 21 connects (joins) the two plates 12. (3) Size of the Metal Cord The size of the metal cord 10 is not particularly limited. As shown in FIGS. 1A to 1E, the diameter of the smallest encompassing circle can be set as the cord diameter of the metal cord 10.

[0098] The minimum inclusive circle means the smallest circle that is in contact with the outer shape of the metal cord 10. Unlike a circumscribing circle, it is not necessary for the minimum inclusive circle to be in contact with all vertices of the metal cord 10.

[0099] The cord diameter, which is the diameter D10 of the smallest encompassing circle of the metal cord 10 in a cross section perpendicular to the longitudinal direction of the metal cord 10, may be, for example, 0.10 mm or more and 0.45 mm or less.

[0100] By making the cord diameter 0.10 mm or more, the tensile strength of the metal cord 10 can be sufficiently increased. By making the cord diameter 0.45 mm or less, when the metal cord 10 is placed inside rubber to form a cord-rubber composite, the thickness of the cord-rubber composite can be reduced, and the cord-rubber composite and rubber products can be made lighter. (4) Shape Along the Length The metal cord 10 may be linear, i.e., a straight cord, without being twisted along the length.

[0101] The metal cord 10 may also be twisted spirally along its length, like a metal cord 50 shown in FIG.

[0102] The metal cord 50 is spirally twisted along its length, which makes it easier for the metal cord 50 to expand and contract along its length when force is applied along its length. Therefore, even when force is applied along its length, the metal cord 50 can be prevented from being damaged.

[0103] By twisting the metal cord 50 spirally along its length, it is possible to form irregularities on the surface of the metal cord 50. Therefore, when the metal cord 50 is placed inside the rubber, the contact area between the metal cord and the rubber increases, improving the adhesion between the two components.

[0104] Furthermore, when the metal cord 50 includes multiple plate-like bodies 12 and filler material 21, the metal cord 10 is twisted spirally along its length, thereby increasing the bonding strength between multiple components.

[0105] When the metal cord 10 is twisted, the twist pitch P of the metal cord 10 is not particularly limited, but may be, for example, 6 mm to 28 mm, or 6 mm to 20 mm. The twist pitch P of the metal cord 10 means the length along the longitudinal direction of the metal cord 10 per pitch when the metal cord 10 is twisted spirally, as shown in Figure 5.

[0106] 6, the composite cord 60 of the present embodiment may be a twisted wire of a plurality of metal cords 10. That is, the composite cord 60 of the present embodiment may be formed by twisting a plurality of metal cords 10 together.

[0107] By forming the composite cord 60 as a twisted wire formed by twisting together a plurality of metal cords 10, when the composite cord 60 is used in a cord-rubber composite or a rubber product and a force is applied along the length of the composite cord 60, the composite cord 60 can be made to easily stretch along the length of the composite cord 60. This makes the cord-rubber composite or the rubber product less susceptible to breakage, and improves durability.

[0108] At least some of the metal cords 10 included in the composite cord 60 may be spirally twisted along the longitudinal direction, as described with reference to Fig. 5. Alternatively, all of the metal cords 10 included in the composite cord 60 may be spirally twisted along the longitudinal direction.

[0109] Furthermore, all of the metal cords 10 included in the composite cord 60 may be straight rather than being twisted spirally along their length.

[0110] Furthermore, the metal cord 10 included in the composite cord 60 may or may not have a filler 21 disposed in the void portion 11 .

[0111] The metal cords 10 included in the composite cord 60 may all have the same structure and material, or some may be different.

[0112] 6 shows an example in which four metal cords 20A are twisted together to form the composite cord 60, but the invention is not limited to this. A composite cord can be formed by twisting together any number of metal cords having any structure.

[0113] [Cord-Rubber Composite] FIG. 7 shows a cross-sectional view of a cord-rubber composite 70 of this embodiment taken along a plane perpendicular to the longitudinal direction of the metal cord 10. As shown in FIG.

[0114] As shown in FIG. 7, the cord-rubber composite 70 of this embodiment can have rubber 71 and the metal cord 10 disposed within the rubber 71 .

[0115] The thickness of the cord-rubber composite 70 can be selected so that the metal cord 10 can be embedded in the rubber 71. Specifically, the thickness T1 of the rubber to be placed above the metal cord 10 and the thickness T2 of the rubber to be placed below the metal cord 10 can be selected.

[0116] The metal cord 10 has the voids 11 therein, and therefore can be made lighter than a cord without the voids 11, i.e., a cord filled with a metal such as steel. This allows the cord-rubber composite 70 of the present embodiment, which includes the metal cord 10, and rubber products to be made lighter.

[0117] The components contained in the cord-rubber composite of this embodiment will be described below. (1) Components Included in the Cord-Rubber Composite (1-1) Metal Cord The cord-rubber composite 70 can include a plurality of metal cords 10. The metal cords 10 contained in the cord-rubber composite 70 can be arranged so that the longitudinal direction of each metal cord 10 is along the Y axis in FIG. 7. The plurality of metal cords 10 can be arranged along the width of the cord-rubber composite 70, i.e., along the X axis in FIG. 7.

[0118] The plurality of metal cords 10 may be arranged in parallel with each other.

[0119] The details of the metal cord 10 have already been explained, so the explanation will be omitted.

[0120] 7 shows an example in which a metal cord 10A is used as the metal cord 10, but the present invention is not limited to this. The metal cord 10 in the cord-rubber composite 70 may be, for example, any of the various metal cords 10 shown in FIGS. 1B to 1E and 2A to 2F. The cord-rubber composite 70 may also contain a plurality of metal cords 10 twisted together to form a composite cord.

[0121] The metal cords 10 in the cord-rubber composite 70 do not need to have the same structure or material, and some or all of the metal cords 10 may differ from the other metal cords 10 in structure, such as the shape of the cross section perpendicular to the longitudinal direction, or material. (1-2) Rubber The rubber 71 in the cord-rubber composite 70 can be produced by molding a rubber composition and vulcanizing it as necessary. The shape of the rubber is not particularly limited, but it can be in the form of a sheet, for example, as shown in Figure 7.

[0122] The specific composition of the rubber is not particularly limited and can be selected depending on the application of various rubber products such as tires to which the cord-rubber composite 70 is applied, the required properties, etc. The rubber can contain, for example, a rubber component, sulfur, and a vulcanization accelerator.

[0123] The rubber component may contain 60% by mass or more, 70% by mass or more, or 100% by mass of one or more types selected from, for example, natural rubber (NR) and isoprene rubber (IR).

[0124] This is because by making the proportion of one or more types of rubber selected from natural rubber and isoprene rubber in the rubber component 60% by mass or more, the breaking strength of the cord-rubber composite 70 and the tire can be increased.

[0125] Examples of rubber components used in combination with natural rubber or isoprene rubber include one or more selected from styrene-butadiene rubber (SBR), butadiene rubber (BR), ethylene-propylene-diene rubber (EPDM), chloroprene rubber (CR), butyl rubber (IIR), and acrylonitrile-butadiene rubber (NBR).

[0126] The sulfur is not particularly limited, but for example, sulfur generally used as a vulcanizing agent in the rubber industry can be used.

[0127] The sulfur content of the rubber is not particularly limited, but may be, for example, 5 parts by mass or more and 8 parts by mass or less per 100 parts by mass of the rubber component.

[0128] This is because, by setting the proportion of sulfur to 5 parts by mass or more per 100 parts by mass of the rubber component, the crosslink density of the resulting rubber can be increased, and in particular, the adhesive strength between the metal cord and the rubber can be increased. Also, by setting the proportion of sulfur to 8 parts by mass or less per 100 parts by mass of the rubber component, the sulfur can be dispersed particularly uniformly in the rubber, and the occurrence of blooming can be reduced.

[0129] The vulcanization accelerator is not particularly limited, and examples thereof include sulfenamide accelerators such as N,N'-dicyclohexyl-2-benzothiazolylsulfenamide, N-cyclohexyl-2-benzothiazolylsulfenamide, N-tert-butyl-2-benzothiazolylsulfenamide, and N-oxydiethylene-2-benzothiazolylsulfenamide. If desired, thiazole accelerators such as 2-mercaptobenzothiazole and di-2-benzothiazolyl disulfide, and thiuram accelerators such as tetrabenzylthiuram disulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrakis(2-ethylhexyl)thiuram disulfide, and tetramethylthiuram monosulfide may also be used.

[0130] The rubber composition used in the cord-rubber composite 70 of this embodiment can be produced by kneading raw materials such as rubber components, heating the mixture, and extruding it.

[0131] The rubber of the cord-rubber composite 70 of this embodiment may contain one or more types selected from simple cobalt and compounds containing cobalt.

[0132] Examples of the cobalt-containing compound include organic acid cobalt and inorganic acid cobalt.

[0133] The organic cobalt salt may be, for example, one or more selected from cobalt naphthenate, cobalt stearate, cobalt neodecanoate, cobalt rosinate, cobalt versatate, cobalt tallate, etc. The organic cobalt salt may be a composite salt in which part of the organic acid is replaced with boric acid.

[0134] As the inorganic acid cobalt, for example, one or more selected from cobalt chloride, cobalt sulfate, cobalt nitrate, cobalt phosphate, and cobalt chromate may be used.

[0135] The rubber may also contain optional components other than the above rubber components, sulfur, vulcanization accelerator, cobalt, etc. The rubber may also contain well-known rubber additives, such as reinforcing agents (carbon black, silica, etc.), wax, and antioxidants. (2) Ends of the Cord-Rubber Composite The number of metal cords 10 in the cord-rubber composite 70 of this embodiment is not particularly limited and can be selected depending on the properties required of the cord-rubber composite 70 and rubber products containing the cord-rubber composite 70. Here, ends refers to the number of metal cords 10 contained per 50 mm width of the cord-rubber composite 70 in a cross section perpendicular to the longitudinal direction of the metal cords 10 of the cord-rubber composite 70. For this reason, in this specification, the unit of ends is "pieces / 50 mm."

[0136] The cord-rubber composite 70 of the present embodiment may include the metal cords 10 so that the ends are, for example, 30 cords / 50 mm or more and 60 cords / 50 mm or less. The ends of the cord-rubber composite 70 may be 36 cords / 50 mm or more and 60 cords / 50 mm or less, or 40 cords / 50 mm or more and 60 cords / 50 mm or less.

[0137] By setting the ends of the cord-rubber composite 70 to 30 pieces / 50 mm or more, the spacing L1 between the metal cords 10 included in the cord-rubber composite 70 can be shortened, and the metal cords 10 can be arranged at a high density. This improves punching resistance, which is a property that prevents foreign objects from penetrating the cord-rubber composite 70. In addition, the bending rigidity of the cord-rubber composite 70 can be easily controlled within a desired range.

[0138] By setting the ends of the cord-rubber composite 70 to 60 cords / 50 mm or less, the number of supply devices that supply the metal cords 10 during production of the cord-rubber composite 70 can be reduced, thereby increasing productivity.

[0139] [Rubber Product] The rubber product of the present embodiment may include a cord-rubber composite according to one aspect of the present disclosure.

[0140] The rubber product of this embodiment may be any of various rubber products that use a cord-rubber composite with a reinforcing material disposed therein, such as tires, belts for conveyor belts, and hoses.

[0141] Here, as an example of the configuration of the rubber product of this embodiment, a tire will be described with reference to FIG.

[0142] The tire of this embodiment may include a metal cord according to one aspect of the present disclosure.

[0143] Fig. 8 shows a cross-sectional view of a tire 80 according to this embodiment taken along a plane perpendicular to the outer periphery. Although Fig. 8 shows only the portion to the left of the center line (CL), the same structure continues to the right of the center line (CL), with the CL as the axis of symmetry.

[0144] As shown in FIG. 8, a tire 80 includes a tread portion 81 , a sidewall portion 82 , and a bead portion 83 .

[0145] The tread portion 81 is the portion that comes into contact with the road surface. The bead portions 83 are located closer to the inner diameter of the tire 80 than the tread portion 81. The bead portions 83 are the portions that come into contact with the rim of a vehicle wheel. The sidewall portions 82 connect the tread portion 81 and the bead portions 83. When the tread portion 81 receives an impact from the road surface, the sidewall portions 82 elastically deform to absorb the impact.

[0146] The tire 80 includes an inner liner 84 , a carcass 85 , a belt layer 86 , and a bead wire 87 .

[0147] The inner liner 84 comprises rubber and seals the space between the tire 80 and the wheel.

[0148] The carcass 85 forms the framework of the tire 80. The carcass 85 may include organic fibers such as polyester, nylon, or rayon, or metal cords, and rubber.

[0149] The bead wire 87 is provided in the bead portion 83. The bead wire 87 receives the tensile force acting on the carcass 85.

[0150] The belt layer 86 tightens the carcass 85 to increase the rigidity of the tread portion 81. In the example shown in Fig. 8, the tire 80 has two belt layers 86. A cord-rubber composite according to one aspect of the present disclosure can be used as the belt layer 86. The cord-rubber composite 70 has already been described, so a description thereof will be omitted.

[0151] As described above, in the tire of this embodiment, the belt layer 86 uses the cord-rubber composite 70 including the metal cord 10 according to one aspect of the present disclosure.

[0152] The metal cord 10 has the voids 11 therein, and therefore can be made lighter than a cord not having the voids 11. Therefore, the rubber product of this embodiment including the metal cord 10 can be made lighter.

[0153] Although the embodiments have been described in detail above, the present invention is not limited to the specific embodiments, and various modifications and changes are possible within the scope of the claims.

[0154] 10 Metal cord 10A Metal cord 10B Metal cord 10C Metal cord 10D Metal cord 10E Metal cord 20A Metal cord 20B Metal cord 20C Metal cord 20D Metal cord 20E Metal cord 20F Metal cord 11 Void portion 12 Plate-shaped body 121 First plate-shaped body 122 Second plate-shaped body 123 Third plate-shaped body 13 Opening 131 First opening 132 Second opening 14 Curved portion D10 Diameter of minimum containing circle (cord diameter) 21 Filler 30A Metal cord 30B Metal cord 31 Chamfered portion 32 Concave portion 33 Convex portion 34 Base material 35 Brass plating film 13A Dotted line 50 Metal cord 60 Composite cord 70 Cord-rubber composite 71 Rubber T1 Rubber thickness T2 Rubber thickness L1 Spacing 80 Tire 81 Tread portion 82 Sidewall portion 83 Bead portion 84 Inner liner 85 Carcass 86 Belt layer 87 Bead wire CL Center line

Claims

1. A metal cord that is placed inside rubber to reinforce the rubber, the metal cord having, in a cross section perpendicular to its longitudinal direction, a void portion and a metal plate-like body that is placed so as to surround at least a part of the void portion.

2. The metal cord according to claim 1, wherein the plate-like body has an opening in the cross section that is connected to the void.

3. The metal cord according to claim 2, wherein the plate-like body has two or more openings in the cross section.

4. A metal cord as set forth in claim 1, wherein the entire outer periphery of the gap is covered by the plate-like body in the cross section.

5. A metal cord according to any one of claims 1 to 4, further comprising a filler material disposed in the voids.

6. A metal cord as claimed in any one of claims 1 to 5, wherein the plate-like body has a wave-like shape with alternating concave and convex portions along its length.

7. A metal cord according to any one of claims 1 to 6, wherein the plate-like body includes a curved portion in the cross section.

8. A metal cord according to any one of claims 1 to 7, wherein the plate-shaped body has at least a first plate-shaped body and a second plate-shaped body.

9. A metal cord according to any one of claims 1 to 8, wherein the diameter of the smallest encompassing circle of the metal cord in the cross section is 0.10 mm or more and 0.45 mm or less.

10. A metal cord according to any one of claims 1 to 9, wherein the metal of the plate-shaped body comprises high carbon steel.

11. A metal cord according to any one of claims 1 to 10, wherein the plate-shaped body has a brass-plated film on the surface.

12. A metal cord according to any one of claims 1 to 11, which is spirally twisted along its length.

13. A composite cord comprising a plurality of twisted metal cords according to any one of claims 1 to 12.

14. A cord-rubber composite comprising: rubber; and a metal cord according to any one of claims 1 to 12 disposed within the rubber.

15. A rubber product comprising the cord-rubber composite of claim 14.

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