Rubber complex and tires

Abstract

Rubber complex (10) comprising a steel cable (11) and a rubber (12) covering at least part of a surface of the steel cable (11), wherein a first covering (131) containing Cu is arranged on an end face (11A) in a longitudinal direction of the steel cable (11).

Description

[0001] The present invention relates to a rubber complex and a tire. [State of the art]

[0002] For example, JP H08-253 004 A discloses that in a pneumatic steel radial tire with a carcass layer of steel plies in which steel cables are embedded, the surfaces of the steel wires forming the steel cable are coated with a predetermined brass coating. [Patent specification]

[0003] JP H08- 253 004 A

[0004] Document JP 55-28 882 B2 concerns a pneumatic tire. The distribution of steel filaments at each end of the steel cable prevents tension at the cable ends and improves the tire's durability.

[0005] Document JP 2019-1 195 A relates to a reinforcing element for a tire, comprising a core cord layer and a spiral cord layer arranged outside the core cord layer. The core cord is inclined with respect to the longitudinal direction of the reinforcing element, and the end face of the core cord at the end section in the lateral direction of the reinforcing element is chamfered.

[0006] Document JP 2010-120 587 A relates to a pneumatic tire in which a bead core of a tire bead is formed by ring-shaped and multiple winding of the bead wire, and a cord is wound spirally around an outer circumference of the bead core, and the connection of the bead wire is provided with a terminal resistor.

[0007] Document JP H11-181 149 A concerns a rubber composition for metal composites. This composition is obtained by mixing 100 parts by weight of at least one rubber component with a sulfur vulcanization system containing 0.5 to 7 parts by weight of sulfur and 0.3 to 15 parts by weight of zinc salt of an organic acid.

[0008] Document JP 2011-42904A concerns a tire cord with brass-plated steel threads in which laminated structural parts are formed by laminating amorphous parts with a composition of 55 to 66 wt% Cu and the remainder Zn and crystalline particles with a particle diameter of no more than 20 nm to crystalline parts with crystalline particles with a particle diameter of less than 20 nm.

[0009] Document WO 2019 / 159 531 A1 relates to a tire with a steel cord with a plating film; and a rubber cover covering the steel cord, the plating film containing Cu and Zn.

[0010] Document CN 117916103 A relates to a metal reinforcement rubberized with a sulfur-crosslinkable, essentially cobalt-free rubberizing compound, wherein the metal reinforcement is a steel cord containing one or more filaments, the filaments comprising steel substrate filaments and a coating that partially or completely covers the steel substrate filaments.

[0011] The rubber complex according to the present invention comprises a steel cable and a rubber covering at least a part of a surface of the steel cable, wherein a first covering containing Cu is arranged on an end face in a longitudinal direction of the steel cable. Fig.Figure 1 shows a perspective view of the rubber complex according to one aspect of the present invention. Fig. Figure 2 shows a cross-sectional view through line AA' of Fig. 1. Fig. Figure 3 shows an explanatory illustration for determining the coverage ratio of the end face in a longitudinal direction of the steel cable. Fig. Figure 4 shows a cross-sectional view of a tire according to one aspect of the present invention. Fig. Figure 5 shows a cross-sectional view of a steel cable according to one aspect of the present invention. [Problem to be solved by the present invention]

[0012] In products containing rubber compounds, such as tires, corrosion can occur near the end face of the steel cable. In recent years, it has become necessary to improve durability in order to reduce the frequency of replacements for products containing rubber compounds, etc. Therefore, suppressing corrosion near the end face of the steel cable is expected.

[0013] Therefore, an objective of the present invention is to provide a rubber complex that can suppress corrosion of the end faces of the steel cable.

[0014] According to the present invention, a rubber complex can be provided which suppresses the corrosion of end faces of the steel cable. [Description of an embodiment of the present invention]

[0015] First, the embodiments of the present invention are listed and described. In the following description, identical or corresponding elements are designated with the same reference numerals, and the same description is not repeated for them.

[0016] (1) A rubber complex according to one aspect of the present invention comprises a steel cable and a rubber covering at least part of a surface of the steel cable, wherein a first covering containing Cu is arranged on an end face in a longitudinal direction of the steel cable.

[0017] The rubber complex according to one aspect of the present invention can increase the corrosion resistance of the end faces of the steel cable by having the first coating on the end faces in the longitudinal direction of the steel cable.

[0018] By including Cu (copper) in the first coating, it is possible to protect the surface of the steel cable, especially the end faces in the longitudinal direction, and to increase corrosion resistance.

[0019] (2) The first covering may also contain S.

[0020] The first coating also contains sulfur (S), which, together with the copper described above, forms a copper-sulfur compound such as Cu₂S. This particularly protects the end faces in the longitudinal direction of the steel cable and significantly increases corrosion resistance. If the steel cable and the rubber are bonded or glued over the first coating, the copper-sulfur compound, such as Cu₂S, increases the bond strength between the steel cable and the rubber, thereby significantly increasing the durability of the rubber compound.

[0021] (3) The first coating may also contain Zn.

[0022] The reaction between copper and other elements contained in the rubber is promoted by zinc (Zn), thus encouraging the formation of copper compounds such as Cu₂S. This copper compound can, in particular, protect the end faces along the longitudinal side of the steel cable and further increase its corrosion resistance. When the steel cable and rubber are bonded via the first coating, the copper compound can increase the bond strength between the steel cable and the rubber, as well as the durability of the rubber compound.

[0023] (4) The first covering may also contain one or more selected materials from Sn, Cr, Fe, Co and Ni.

[0024] Tin (Sn), chromium (Cr), iron (Fe), cobalt (Co), and nickel (Ni) have higher ionization tendencies than zinc (Zn). Therefore, in addition to copper (Cu) and zinc (Zn), the first coating contains one or more selected elements from Sn, Cr, Fe, Co, and Ni, allowing it to act as sacrificial corrosion protection or to further enhance the synthesis or composite potential of Cu and zinc. This provides extra protection for the end faces along the length of the steel cable and further increases its corrosion resistance.

[0025] (5) The end face of the steel cable may be covered with the rubber over the first covering.

[0026] Since the end face of the steel cable is covered by the first layer of rubber, it can be further protected by the rubber in addition to this first layer. Therefore, the corrosion resistance of the end faces in the longitudinal direction of the steel cable can be improved. Furthermore, it is possible to suppress damage to the rubber compound and increase its durability.

[0027] (6) The end face of the steel cable may be connected to the rubber via the first covering.

[0028] By connecting the end face of the steel cable to the rubber via the first coating, the end faces along the longitudinal direction of the steel cable can be protected by the rubber in addition to the first coating. Therefore, the end face along the longitudinal direction of the steel cable can be protected, and its corrosion resistance can be increased.

[0029] When the rubber compound is applied to a tire or similar component, a significant force is easily exerted near the interface between the longitudinal end face of the steel cable and the rubber. Since the longitudinal end face of the steel cable is connected to the rubber via the first coating, the rubber, the first coating, and the steel cable together absorb the applied force. This effectively prevents damage to the rubber compound and increases its durability.

[0030] Furthermore, the end face of the steel cable, the first covering, and the rubber are bonded together, thus preventing the ingress of foreign matter such as water between these components. This prevents foreign matter such as water from reaching the end face of the steel cable, which significantly increases corrosion resistance.

[0031] (7) The first covering can cover 20% or more of the frontal area.

[0032] If the first coating covers 20% or more of the end face in the longitudinal direction of the steel cable 11, the corrosion resistance of the end face of the steel cable can be increased in particular.

[0033] (8) A second covering containing Cu may be arranged on a side face of the steel cable.

[0034] The rubber complex with the second coating on the side surface of the steel cable can improve the corrosion resistance of the sides of the steel cable.

[0035] By including Cu in the second coating, the surface of the steel cable, especially the side surface, can be protected and corrosion resistance improved.

[0036] (9) A tire according to one aspect of the present invention may comprise the rubber complex according to any one of the above points (1) to (8).

[0037] A tire according to one aspect of the present invention comprises the rubber complex described above. For this reason, it is possible to suppress corrosion on the longitudinal side surfaces of the steel cable and to improve its durability. Sacrificial corrosion protection [Details of embodiments of the present invention]

[0038] Specific examples of the rubber complex, the tire, and the steel cable according to one embodiment of the present invention (hereinafter referred to as "the present embodiment") are described with reference to the drawings. It should be noted that the present invention is not limited to these examples and is not defined by the claims, and that all modifications are encompassed within the meaning and scope equivalent to the claims. [Rubber composite]

[0039] In products containing rubber compounds, such as tires, corrosion can occur near the end face of the steel cable. To suppress the occurrence of such corrosion, the inventors of the present invention investigated the causes of the corrosion.

[0040] As already mentioned, it is common to apply a coating to the surface of the wires of the steel cable.

[0041] When a rubber compound is manufactured using a coated steel cable, the metallic components of the coating react with the rubber components to form a coating, also known as an adhesive layer, on the surface of the steel cable. It is believed that this coating protects the steel cable and increases its corrosion resistance.

[0042] During the production of the rubber compound, the steel cables must be cut to the size of the compound. This leaves the wires exposed at the end faces of the steel cable within the rubber compound, preventing the formation of a protective coating on these faces. Consequently, the end faces of the steel cable are unprotected in conventional rubber compounds, leading to the assumption that corrosion has occurred.

[0043] Based on the above discussion results, the inventors of the present invention have completed the rubber complex of the present embodiment, which can suppress corrosion on the end face of the steel cable.

[0044] In Fig. 1 and Fig. Figure 2 shows example structures of the rubber complex of the present embodiment. Fig. Figure 1 shows a perspective view of the rubber complex 10 of the present embodiment. Fig.Figure 2 shows a cross-sectional view through line AA' of Fig. 1, namely a cross-sectional representation on a plane that lies at the end of the steel cable 11 in the longitudinal direction and passes through the central axis of the steel cable 11. In Fig. 1 and Fig. 2 is the direction of the Y-axis parallel to the longitudinal direction of the steel cable 11, and the XZ-plane is a plane perpendicular to the longitudinal direction of the steel cable 11. In the Fig. 1 and Fig. 2. The direction of the X-axis is the width direction of the rubber complex 10, and a plurality of steel cables 11 are arranged in a row along the direction of the X-axis. The direction of the Z-axis is the thickness direction of the rubber complex 10.

[0045] As in Fig.As shown in Figure 1, the rubber complex 10 of the embodiment can comprise a steel cable 11 and a rubber 12 that covers at least part of the surface of the steel cable 11. Furthermore, the first covering 131, which is the covering 13, is present on the end face 11A in the longitudinal direction of the steel cable 11, as shown in Figure 1. Fig. 2 shown.

[0046] The number of steel cables 11 comprising the rubber complex 10 of the embodiment is not particularly limited and can be selected according to the application; for example, it can be one or more than one steel cable. If the rubber complex 10 of the embodiment comprises a plurality of steel cables 11, the arrangement of the steel cables 11 is not particularly limited, but as shown in Fig. As shown in Figure 1, the steel cables 11 can, for example, be arranged in a row in the XZ plane, which is a cross-section perpendicular to the longitudinal direction of the steel cables 11.

[0047] Each component of the rubber complex is described below. (1) steel cables

[0048] The steel cable 11, as in Fig. Figure 2 shows a wire 111 and a coating 112 covering the surface of the wire 111. Fig. 1 and Fig. Figure 2 shows the steel cable 11 as an example with a single wire, but it is not limited to this form. For example, it can be a steel cable having several steel wires twisted together. If the steel cable has a structure in which several steel wires are twisted together, preferably, as described below, each steel cable has a wire 111 and a coating 112 covering the surface of the wire 111.

[0049] The wire 111 contained in the steel cable 11 can, for example, be a steel wire, and preferably a high carbon steel wire can also be used.

[0050] The steel cable 11 can have a first coating 1121 as a coating 1122, which covers the side of the end face 11A of the steel cable 11, in addition to the second coating 1122, which covers the side of the end face 11B of the steel cable 11.

[0051] By providing the coating 112 on the surface of the wire 111 of the steel cable 11, the covering 13 can be formed on the surface of the steel cable 11 during the formation of the rubber complex 10. Specifically, when the rubber complex 10 is formed by providing the first coating 1121, which covers the side of the end face 11A in the longitudinal direction of the steel cable 11, the first covering 131 can be formed and arranged on the end face 11A in the longitudinal direction of the steel cable 11.

[0052] Furthermore, by providing the second coating 1122, which covers the side of the side surface 11B of the steel cable 11, the second covering 132 can be formed and arranged on the side of the side surface 11B of the steel cable 11 when forming the rubber complex 10.

[0053] The first coating 1121 and the second coating 1122 can react with the rubber components during the formation of the rubber complex 10, and the first covering 131 and the second covering 132 can be formed. Therefore, the first coating 1121 and the second coating 1122 may remain partially intact during the formation of the rubber complex 10. The first coating 1121 and the second coating 1122 may also become the first covering 131 and the second covering 132. That is, the rubber complex 10 may have neither a first coating 1121 nor a second coating 1122.

[0054] As described above, the production of the rubber compound requires cutting the steel cable to the size of the compound. Therefore, conventional rubber compounds do not form a coating on the end face along the longitudinal direction of the steel cable. It is proposed that the coating be formed by a reaction between components of the rubber compound and components of the steel cable's coating. However, without a coating on the end face along the longitudinal direction of the steel cable, no coating is formed, and corrosion will occur along the end face of the steel cable with conventional rubber compounds.

[0055] On the other hand, the steel cable 11, which is contained in the rubber complex 10 of the present embodiment, has the first coating 1121, comprising the coating 112, on the end face 11A in the longitudinal direction. Therefore, the rubber complex 10 has a first coating 131 on the end face in the longitudinal direction of the steel cable 11, which increases the corrosion resistance of the end face 11A of the steel cable.

[0056] The steel cable 11, which is contained in the rubber complex 10 of the present embodiment, can have a second coating 1122, which is coating 112, on side 11B. Thus, the rubber complex 10 can have a second covering 132 on the side surface of the steel cable 11, which can also increase the corrosion resistance of side surface 11B of the steel cable.

[0057] The first coating 1121 can be formed after the steel cable is cut to the predetermined length to produce the rubber complex 10. In particular, the first coating 1121 can be formed before embedding the steel cable 11 in the rubber 12, or after embedding a portion of the steel cable 11 in the rubber 12, before covering the end face in the longitudinal direction of the steel cable 11 with the rubber 12, or the like.

[0058] The specific means for forming the first coating 1121 are not particularly limited, and various means r can be used to form a coating with a desired composition. For example, the first coating 1121 can contain one or more selected oxides and metals. Therefore, the first coating 1121 can be formed by various means around an oxide or a metal. Examples of methods for producing the first coating 1121 include a coating method in which a coating fluid containing a predetermined component such as metal is applied, an immersion method in which the end face 11A of the steel cable 11 is immersed in the coating fluid, and the like.

[0059] Other methods for producing the first coating 1121 may include electroplating or galvanic plating, electroless plating, substitute plating, and the like. An example of an electroplating method is brush plating. If the first coating 1121 contains multiple components, it can also be formed by applying multiple layers, corresponding to the multiple components in the first coating 1121, to the end face in the longitudinal direction of the steel cable 11, and performing heat treatment as required. Preferably, a pretreatment such as degreasing is carried out on the end face 11A of the steel cable 11 before forming the first coating 1121 to remove substances adhering to the surface, but the first coating 1121 can be formed without performing the pretreatment.

[0060] The method for forming the second coating 1122 is not particularly limited. For example, a suitable coating can be formed on the surface of the conductor or base wire to manufacture the steel cable 11, and the conductor can be drawn so that a second coating 1122 can be formed on the surface of the wire 111. That is, the second coating 1122, which is located on the side of the side surface 11B of the steel cable 11, originates from the coating that is formed on the surface of the conductor before the wire is drawn.

[0061] As described above, the first coating 1121, which is applied to the end face 11A of the steel cable 11, and the second coating 1122, which is applied to the side face 11B, are formed at different times. Therefore, the composition and thickness of the first coating 1121 and the second coating 1122 can be the same or different.

[0062] The compositions of the first coating 1121 and the second coating 1122, which are the coatings 112, are not particularly restricted. The coating 112 preferably contains, for example, Cu (copper). In particular, it is more preferred to contain Zn (zinc) in addition to Cu.

[0063] Furthermore, in addition to Cu and Zn, the coating 112 may preferably contain one or more selected elements from Sn (tin), Cr (chromium), Fe (iron), Co (cobalt) and Ni (nickel). (2) Rubber

[0064] Rubber 12 can be manufactured by molding a rubber compound and vulcanizing it if required.

[0065] The specific composition of the rubber can be selected according to its use and the properties of the rubber complex in the present embodiment and is not particularly limited. For example, the rubber may contain the rubber component, sulfur, and a vulcanization accelerator.

[0066] The rubber component contains one or more selected materials, for example, natural rubber (NR: nature rubber) and isoprene rubber (IR: isoprene rubber), preferably greater than or equal to 60% by mass, more preferably greater than or equal to 70% by mass, and particularly preferably 100% by mass.

[0067] The breaking strength of the rubber complex can be increased by preferably setting the proportion of one or more rubbers selected from natural rubber and isoprene rubber in the rubber component to greater than or equal to 60% by mass.

[0068] Examples of rubber components used in combination with natural rubber or isoprene rubber may 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).

[0069] The sulfur is not particularly limited, but for example, sulfur that is commonly used as a vulcanizing agent in the rubber industry can be used.

[0070] The sulfur content in the rubber is not particularly limited, but is preferably greater than or equal to 5 mass fraction and less than or equal to 8 mass fraction based on 100 mass fraction of the rubber component.

[0071] Since the crosslinking density of the resulting rubber can be increased, and in particular the adhesive strength between the steel cable and the rubber can be increased, by ensuring that the sulfur content is greater than or equal to 5 mass fractions per 100 mass fractions of the rubber component. Since the sulfur content is less than or equal to 8 mass fractions per 100 mass fractions of the rubber component, sulfur can preferably be dispersed particularly uniformly in the rubber, thus suppressing blooming.

[0072] The vulcanization accelerator is not particularly restricted, but sulfenamide accelerators are preferably used, for example, N,N'-dicyclohexyl-2-benzothiazolylsulfenamide, N-cyclohexyl-2-benzothiazolylsulfenamide, N-tert-butyl-2-benzosulfenamide, N-oxydiethylene-2-benzothiazolylsulfenamide. Thiazole accelerators can also preferably be used, for example, 2-mercaptobenzothiazole, di-2-benzothiazolyl disulfide. Thiuram accelerators can also preferably be used, for example, tetrabenzyl thiuram disulfide, tetramethylthiuram disulfide, tetraethylthiuram disulfide, tetrakis(2-ethylhexyl) thiuram disulfide, tetramethylthiuram monosulfide.

[0073] The rubber composition used for the rubber complex of the present embodiment can be produced by kneading, heating and extruding each of the components described above using a conventional method.

[0074] Furthermore, the rubber of the rubber complex of the present embodiment preferably contains one or more compounds selected from cobalt alone and cobalt-containing compounds.

[0075] Examples of cobalt-containing compounds can include organic cobalt salts and inorganic cobalt salts.

[0076] The organic cobalt salts may preferably include one or more selected compounds such as cobalt naphthenate, cobalt stearate, cobalt neodecanoate, cobalt trosinate, cobalt versatate, cobalt talate, and the like. The organic cobalt salt may be a compound salt in which the organic acid is partially replaced by boric acid.

[0077] For example, one or more of the following inorganic cobalt salts may preferably be selected: cobalt chloride, cobalt sulfate, cobalt nitrate, cobalt phosphate, or cobalt chromate.

[0078] In particular, the rubber of the rubber complex of the present embodiment more preferably contains organic cobalt salts, since the initial adhesion between the steel cable and the rubber can be significantly improved by the inclusion of the cobalt salts. Initial adhesion refers to the adhesion between the steel cable and the rubber during tire production, immediately after vulcanization.

[0079] According to the inventors' study of the present invention, adding cobalt to rubber increases the proportion of copper compounds such as Cu₂S in the coating and enhances the adhesion between the steel cable and the rubber. This effect is particularly noticeable when an organic cobalt salt is used as the cobalt. Therefore, the rubber of the rubber complex in the present embodiment preferably contains cobalt, especially organic cobalt, resulting in a rubber complex with particularly excellent adhesion.

[0080] Furthermore, the rubber may contain optional components in addition to the rubber component mentioned above, such as sulfur, vulcanization accelerators, cobalt, and the like. The rubber may also contain known rubber additives, such as reinforcing agents (carbon black, silica, etc.), waxes, antioxidants, and the like.

[0081] The rubber 12 can cover at least part of the surface of the steel cable 11. By covering at least part of the surface of the steel cable 11 with the rubber 12, even in the section not directly covered by the rubber 12 and provided with the coating 112 described above, the components of the coating 112 and the components of the rubber 12 can react to form the coating 13, thereby improving corrosion resistance.

[0082] Therefore, the rubber 12 can, for example, cover at least part of the end face 11A of the steel cable 11, or it can cover the entire end face 11A. Furthermore, the rubber 12 can cover at least a section of the side face 11B of the steel cable 11, or it can cover the entire side face 11B of the steel cable 11. The rubber 12 can also cover the entire surface of the steel cable 11.

[0083] From the point of view of protecting the end faces 11A in the longitudinal direction of the steel cable 11 and in particular improving corrosion resistance, the rubber 12 preferably covers at least a part of the end faces 11A in the longitudinal direction of the steel cables 11, and more preferably the entire end face 11A in the longitudinal direction of the steel cables 11. (3) Coverage (3-1) First Coverage

[0084] As described above, in the rubber complex 10 of the present embodiment, the end faces 11A in the longitudinal direction of the steel cables 11 can have the first covering 131, which is the covering 13.

[0085] Fig. Figure 2 shows an example where the first covering 131 is formed with a uniform thickness along the end face 11A in the longitudinal direction of the steel cable 11. Fig.Figure 2, however, shows only a schematic representation and is not limited to such a form. For example, the first covering 131 can be arranged so that it is distributed on the surface of the end face 11A in the longitudinal direction of the steel cable 11. It can be, as in Fig. 2 shown, have a film-like shape to cover the entire end face 11A in the longitudinal direction of the steel cable 11.

[0086] It is assumed that the first coating 131 is formed by the reaction between the components contained in the first coating 1121 and the components contained in the rubber 12, etc. Therefore, the composition of the first coating 131 varies depending on the composition of the first coating 1121 or the rubber 12 and is not particularly limited, but the first coating 131 preferably contains, for example, Cu (copper). This makes it possible to protect the surface of the steel cable 11, especially the longitudinal end faces, and to increase its corrosion resistance by including Cu in the first coating 131.

[0087] As described above, the first coating 1121 may contain Zn (zinc) in addition to Cu. In addition to Cu and Zn, the first coating 1121 may also contain one or more selected elements from Sn (tin), Cr (chromium), Fe (iron), Co (cobalt), and Ni (nickel). Therefore, the first covering 131 may contain Zn in addition to Cu. In addition to Cu and Zn, the first covering 131 may also contain one or more selected elements from Sn, Cr, Fe, Co, and Ni.

[0088] If the first coating 1121 contains Zn in addition to Cu, the first covering 131 can also contain Zn in addition to Cu. Zn promotes the reactions between Cu and other elements contained in the rubber, thereby promoting the formation of copper compounds such as Cu₂S. The copper compound can, in particular, protect the end faces 11A in the longitudinal direction of the steel cables 11 and further increase corrosion resistance. If the steel cable 11 and the rubber 12 are bonded together by the first covering 131, the copper compound can increase the adhesion between the steel cable and the rubber, thereby increasing the durability of the rubber complex.

[0089] Sn, Cr, Fe, Co, and Ni have higher ionization tendencies than Zn. Therefore, in addition to Cu and Zn, the first coating 131 also contains one or more selected Sn, Cr, Fe, Co, and Ni, which allows it to act as sacrificial corrosion protection or further enhance the synthesis or composite potential of Cu and Zn. This provides special protection for the end faces 11A in the longitudinal direction of the steel cable 11 and further increases its corrosion resistance.

[0090] Vulcanization is typically carried out in the production of the rubber complex. Therefore, the first coating 131 more preferably also contains S (sulfur), which is added during vulcanization. By further containing S in the first coating 131, a copper-sulfur compound such as Cu and Cu₂S is formed, which in particular protects the end face 11A in the longitudinal direction of the steel cable 11 and can especially increase its corrosion resistance. When the steel cable 11 and the rubber 12 adhere to each other via the first coating 131, the copper-sulfur compound such as Cu₂S further increases the adhesion between the steel cable 11 and the rubber, thereby in particular increasing the durability of the rubber complex.

[0091] The first coating 131 can also contain some of the components of the first coating 1121. The first coating 1121 can contain one or more selected oxides and metals, as described above. Therefore, the first coating 131 can also contain one or more selected oxides and metals derived from the first coating 1121. Because the first coating 131 contains one or more selected oxides and metals, the strong adhesion with the first coating 1121 is particularly high. For this reason, the corrosion resistance of the steel cable 11 is significantly increased, and the adhesive force between the steel cable 11 and the rubber 12 can be increased at the points where the steel cable 11 and the rubber 12 adhere.

[0092] In the rubber complex 10 of the present embodiment, the rubber 12 preferably covers at least a part of the end faces 11A in the longitudinal direction of the steel cable 11 and further preferably the entire end faces 11A in the longitudinal direction of the steel cable 11, as described above.

[0093] In the manufacture of the rubber complex 10, if the rubber 12 is arranged such that it covers at least a portion of the end faces 11A in the longitudinal direction of the steel cable 11 as described above, then the end faces 11A can adhere to the rubber 12 via the first covering 131 in the longitudinal direction of the steel cable 11. That is, from the outer surface side of the rubber complex 10, the rubber 12, the first covering 131, and the steel cable 11 are arranged in that order on the side of the end face 11A in the longitudinal direction of the steel cable 11, so that each component of the rubber 12, the first covering 131, and the steel cable 11 can adhere to one another.

[0094] By connecting the end face 11A to the rubber 12 in the longitudinal direction of the steel cable 11 via the first covering 131, the end faces 11A in the longitudinal direction of the steel cable 11 can be protected by the rubber 12 in addition to the first covering 131. Therefore, the end faces 11A in the longitudinal direction of the steel cable 11 can be protected and the corrosion resistance increased.

[0095] When the rubber compound 10 is applied to a tire or the like, a large force is easily exerted near the boundary between the end face 11A in the longitudinal direction of the steel cable 11 and the rubber 12. Since the end face 11A adheres to the rubber 12 via the first coating 131 in the longitudinal direction of the steel cable 11, the rubber 12, the first coating 131, and the steel cable 11 together can absorb the applied force. This, in particular, prevents damage to the rubber compound 10 and increases its durability.

[0096] Furthermore, the end face 11A, the first covering 131, and the rubber 12 adhere to one another in the longitudinal direction of the steel cable 11, thus preventing, in particular, the ingress of foreign matter such as water between these components. This prevents the ingress of foreign matter such as water up to the end face 11A of the steel cable 11, which in particular increases corrosion resistance.

[0097] However, if, for example, the rubber complex 10 is used over a long period of time, the reaction between the components of the rubber 12 and the components of the first coating 1121 continues, which can change the condition of the first coating 131 and its surroundings. Furthermore, forces can be repeatedly applied between the rubber 12 and the steel cable 11, and a gap or the like can be created between the two components. Therefore, if the rubber complex 10 is used over a long period of time, the adhesive force between the rubber 12 and the steel cable 11 can decrease.

[0098] Even if the adhesive force between the rubber 12 and the steel cable 11 is reduced, it can have the effect of protecting the end face 11A of the steel cable 11 and increasing corrosion resistance, since in the rubber complex 10 the first covering 131 is arranged on the end face 11A of the steel cable 11.

[0099] For this reason, the end face 11A in the longitudinal direction of the steel cable 11 is not limited to the shape in which it adheres to the rubber 12 via the first covering 131. The end face 11A in the longitudinal direction of the steel cable 11 can be covered by the rubber via the first covering.

[0100] Since the end face 11A in the longitudinal direction of the steel cable 11 is covered by the first layer of rubber 12, the end face 11A in the longitudinal direction of the steel cable 11 can be additionally protected by the rubber 12 beyond the first layer 131. Therefore, the corrosion resistance of the end faces 11A in the longitudinal direction of the steel cable 11 can be improved. Furthermore, it is possible to suppress damage to the rubber compound 10 and increase its durability.

[0101] The fact that the end face 11A is covered in the longitudinal direction of the steel cable above with the rubber 12 via the first covering 131 encompasses the aforementioned case of adhesion and the following two forms. In the first form, starting from the side of the outer surface of the rubber complex 10, the rubber 12, the first covering 131, and the steel cable 11 are arranged in that order on the end face 11A in the longitudinal direction of the steel cable 11, and each element is in contact with the others. "Each element is in contact with the others" here means that there is no adhesive force between each element, but they are in complete contact with each other. In the second form, starting from the side of the outer surface of the rubber complex 10, the rubber 12, the first covering 131, and the steel cable 11 are arranged in that order on the end face 11A in the longitudinal direction of the steel cable 11, with at least one gap between each element, at least in part.

[0102] In any form in which the end face 11A is covered with rubber in the longitudinal direction of the steel cable 11 over the first covering 131, a first coating 1121 can be arranged on the surface of the steel cable 11 that is opposite the first covering 131.

[0103] As described above, since the first coating 1121, which is coating 112, was not formed on the end face 11A of the steel cable 11, the first covering 131 was also not arranged on the end face 11A of the steel cable 11. Therefore, as long as the first covering 131 is arranged even slightly on the end face 11A of the steel cable 11, the corrosion resistance can be improved compared to the conventional one, and the extent to which the first covering 131 is arranged is not particularly limited. The first coating 131 preferably covers 20% or more, and more preferably 40% or more, of the area of ​​the end face 11A in the longitudinal direction of the steel cable 11. It is preferred that the first coating 131 covers 20% or more, and more preferably, the area of ​​the end face 11A in the longitudinal direction of the steel cable 11, because this can particularly increase the corrosion resistance of the end faces 11A of the steel cable 11.

[0104] Since the first covering 131 can cover the entire end face 11A of the steel cable 11, the first covering 131 can cover less than or equal to 100% of the area of ​​the end face 11A of the steel cable 11.

[0105] A method for measuring the proportion of the area where the first covering 131 covers the end face 11A of the steel cable 11 is not particularly restricted.

[0106] For example, if the end-face rubber 121 is removed, which is at least part of the rubber 12 arranged on the end-face side 11A of the steel cable 11 in the rubber complex 10, the end-face side 11A of the steel cable 11 is exposed, as shown in Fig.Figure 3 shows. Therefore, it is possible to calculate the proportion of the area occupied by the rubber 12 on the end face 11A of the steel cable 11, excluding the area where the steel cable 11 is exposed, as with the first coating 1121. Since the rubber 12 remaining on the end face 11A of the steel cable 11 corresponds to the section where the first coating 131 was formed, the proportion of the area where the first coating 131 covers the end face 11A of the steel cable 11 can be calculated, as described above, according to the proportion of the area occupied by the rubber 12.

[0107] Furthermore, when the end-face rubber 121 is removed, a mapping of the element distribution can be performed either on the end-face rubber 121 or on the end face 11A of the steel cable 11 exposed after removal, and the proportion of the area where the first covering 131 covers the end face 11A of the steel cable 11 can be measured. If the rubber remains on the end face 11A of the steel cable, a mapping of the element distribution can be performed on the end face 11A of the steel cable. If no rubber remains on the end face 11A of the steel cable, a mapping of the element distribution can be performed on the end face rubber 121.

[0108] When mapping the element distribution, the area in which both the components of the first coating 1121 and the components of the rubber, for example Cu and S, are distributed is the area in which the first coating 131 is formed. Therefore, from the result of the element distribution mapping, the proportion of the area where the first coating 131 is formed can be determined on the end face 11A of the steel cable 11. This allows the calculation of the proportion of the area where the first coating 131 covers the end face 11A of the steel cable 11.

[0109] The methods for mapping the elemental distribution are not particularly limited; SEM-EDX (Scanning Electron Microscope-Energy Dispersive X-ray Spectroscopy) or similar techniques can be used. If the elemental distribution mapping is performed on the end face of the rubber, for example, because the object being measured is an insulator, low-voltage SEM and EDX can be employed. (3-2) Second cover

[0110] The rubber complex 10 can also have a second coating 132 as the coating 13 on the side surface 11B of the steel cable 11. It is assumed that the second coating 132 is formed by the reaction between the components contained in the second coating 1122 and the components contained in the rubber 12, etc. Therefore, the composition of the second coating 132 varies depending on the composition of the second coating 1122 or the rubber 12 and is not particularly limited, but the second coating 132 preferably contains, for example, Cu (copper). This makes it possible to protect the surface of the steel cable 11, especially the end faces in the longitudinal direction, and to increase its corrosion resistance by including Cu in the second coating 132.

[0111] As described above, the second coating 1122 can contain Zn (zinc) in addition to Cu. Therefore, the second coating 132 can also contain Zn in addition to Cu. Zn promotes the reactions between Cu and other elements contained in the rubber, thereby promoting the formation of copper compounds such as Cu₂S. The copper compound can, in particular, protect the side faces 11B of the steel cables 11 and further increase corrosion resistance. When the steel cable 11 and the rubber 12 are bonded together by the second coating 132, the copper compound can increase the adhesion between the steel cable and the rubber, thereby increasing the durability of the rubber complex.

[0112] In addition to Cu and Zn, the second coating 1122 can further contain one or more selected elements from Sn (tin), Cr (chromium), Fe (iron), Co (cobalt), and Ni (nickel). Therefore, the second coating 132 can contain, in addition to Cu and Zn, one or more selected elements from Sn, Cr, Fe, Co, and Ni. Sn, Cr, Fe, Co, and Ni have higher ionization tendencies than Zn. Therefore, the second coating 132 contains, in addition to Cu and Zn, one or more selected elements from Sn, Cr, Fe, Co, and Ni, which allows it to act as sacrificial corrosion protection or to further enhance the synthesis or composite potential of Cu and Zn. This allows the side surfaces 11B of the steel cable 11 to be particularly well protected and its corrosion resistance to be further increased.

[0113] The second coating 132 further preferably contains S (sulfur), which is added during vulcanization. By further containing S in the second coating 132, a copper-sulfur compound such as Cu and Cu₂S can be formed. When the steel cable 11 and the rubber 12 adhere to each other via the second coating 132, the copper-sulfur compound can further increase the adhesive strength between the steel cable 11 and the rubber, thereby particularly increasing the durability of the rubber complex.

[0114] In the rubber complex 10 of the present embodiment, the rubber 12 preferably covers at least a part of the side surfaces 11B of the steel cable 11 and further preferably the entire side surfaces 11B of the steel cable 11, as described above.

[0115] In the manufacture of the rubber complex 10, if the rubber 12 is arranged such that it covers at least a portion of the side surface 11B of the steel cable 11 as described above, then the side surface 11B of the steel cable 11 can adhere to the rubber 12 via the second covering 132. That is, from the outer surface of the rubber complex 10, the rubber 12, the second covering 132, and the steel cable 11 are arranged in this order on the side of the side surface 11B of the steel cable 11 so that each component of the rubber 12, the second covering 132, and the steel cable 11 can adhere to one another.

[0116] By connecting the side surface 11B of the steel cable 11 to the rubber 12 via the second covering 132, the side surface 11B of the steel cable 11 can be additionally protected by the rubber 12 in addition to the second covering 132. Therefore, the side surface 11B of the steel cable 11 can be protected and its corrosion resistance increased.

[0117] When the rubber complex 10 is applied to a tire or the like, a considerable force is easily exerted near the boundary between the side surface 11B of the steel cable 11 and the rubber 12. Since the side surface 11B of the steel cable 11 adheres to the rubber 12 via the second coating 132, the rubber 12, the second coating 132, and the steel cable 11 together can absorb the applied force. This, in particular, prevents damage to the rubber complex 10 and increases its durability.

[0118] Furthermore, the side surface 11B of the steel cable 11, the second covering 132, and the rubber 12 adhere to one another, thus preventing, in particular, the ingress of foreign matter such as water between these components. This prevents the ingress of foreign matter such as water up to the side surface 11B of the steel cable 11, which in particular increases its corrosion resistance.

[0119] However, if, for example, the rubber complex 10 is used over a long period of time, the reaction between the components of the rubber 12 and the components of the second coating 1122 continues, and the condition of the second coating 132 and its surroundings can change. Furthermore, forces can be repeatedly applied between the rubber 12 and the steel cable 11, and a gap or the like can be created between the two components. Therefore, if the rubber complex 10 is used over a long period of time, the adhesive force between the rubber 12 and the steel cable 11 can decrease.

[0120] However, even if the adhesive force between the rubber 12 and the steel cable 11 is reduced, it can have the effect of protecting the side surface 11B of the steel cable 11 and increasing corrosion resistance, since in the rubber complex 10 the second covering 132 is arranged on the side surface 11B of the steel cable 11.

[0121] For this reason, the side surface 11B of the steel cable 11 is not limited to the shape in which it adheres to the rubber 12 via the second covering 132. The side surface 11B of the steel cable 11 can be covered with rubber via the second covering.

[0122] Since the side surface 11B of the steel cable 11 is covered by the second layer of rubber 12, the side surface 11B of the steel cable 11 can be further protected by the rubber 12 in addition to the second layer 132. Therefore, the corrosion resistance of the side surfaces 11B of the steel cable 11 can be improved. Furthermore, it is possible to suppress damage to the rubber compound 10 and increase its durability.

[0123] The fact that the side surface 11B of the above steel cable is covered with the rubber 12 via the second covering encompasses the aforementioned case of adhesion and the following two forms. In the first form, starting from the side of the outer surface of the rubber complex 10, the rubber 12, the second covering 132, and the steel cable 11 are arranged in that order on the side surface 11B of the steel cable 11, and each component is in contact with the others. "Each component is in contact with the others" here means that there is no adhesive force between each component, but they are in complete contact with each other. In the second form, starting from the side of the outer surface of the rubber complex 10, the rubber 12, the second covering 132, and the steel cable 11 are arranged in that order on the side surface 11B of the steel cable 11, and there is at least one gap between each component, at least in part.

[0124] In any form in which the side surface 11B of the steel cable 11 is covered with rubber over the second covering 132, a second coating 1122 can be arranged on the surface of the steel cable 11 opposite the second covering 132. [Tires]

[0125] The tire in this embodiment is described with reference to Fig. 4 described.

[0126] The tire according to the embodiment can comprise the rubber complex described above.

[0127] Fig. Figure 4 shows a sectional view of the tire 40 according to the present embodiment in a plane perpendicular to the circumferential direction. Fig. Figure 4 shows only the left side section of CL (central line), while the same structure is shown continuously on the right side of CL with CL as the axis of symmetry.

[0128] As in Fig.As shown in Figure 4, the tire 40 includes a tread section 41, a sidewall section 42 and a bead section 43.

[0129] The tread section 41 is in contact with the road surface. The bead section 43 is located on the inner diameter side of the tire 40, relative to the tread section 41. The bead section 43 is in contact with the rim of the vehicle's wheel. The sidewall section 42 connects the tread section 41 and the bead section 43. When the tread section 41 receives an impact from the road surface, the sidewall section 42 deforms elastically and absorbs the impact.

[0130] The tire 40 has an inner liner 44, a carcass 45, a belt layer 46 and a bead wire 47.

[0131] The inner liner 44 is made of rubber and seals the space between the tire 40 and the wheel.

[0132] The carcass 45 forms the skeleton of the tire 40. The carcass 45 consists of rubber and organic fibers such as polyester, nylon, and rayon, or steel cords. The rubber compound described above can also be used for the carcass 45.

[0133] The bead wire 47 is provided in the bead section 43. The bead wire 47 absorbs the tensile force acting on the carcass 45.

[0134] The belt layer 46 tightens the carcass 45 to increase the stiffness of the tread section 41. In Fig. In the example shown, tire 40 has two belt layers 46.

[0135] The two belt layers 46 can be stacked on top of each other in the radial direction of the tire 40 and the rubber complex already described can be used.

[0136] A tire according to this embodiment comprises the rubber complex described above. For this reason, it is possible to suppress corrosion on the longitudinal side surfaces of the steel cable and to improve durability. [Steel cable]

[0137] The steel cable of this embodiment can have the same configuration as the steel cable 11 described in the rubber complex. Therefore, some overlapping explanations are omitted.

[0138] Fig. Figure 5 shows a schematic cross-sectional view in a plane passing through the central axis of the steel cable 11. Fig. 5 is the direction of the Y-axis parallel to the longitudinal direction of the steel cable 11 and the XZ-plane is a plane perpendicular to the longitudinal direction of the steel cable 11.

[0139] The steel cable 11 according to this embodiment, as in Fig.Figure 5 shows a wire 111 and a coating 112 covering the surface of the wire 111. Fig. Figure 5 shows the steel cable 11 as an example with a single wire, but it is not limited to this form. For example, it can be a steel cable consisting of several steel wires twisted together. If the steel cable has a structure in which several steel wires are twisted together, preferably, as described below, each steel cable has a wire 111 and a coating 112 covering the surface of the wire 111.

[0140] The wire 111 contained in the steel cable 11 can, for example, be a steel wire, and a steel wire with a high carbon content can be further preferred.

[0141] The steel cable 11 can have a first coating 1121 covering the end face in the longitudinal direction of the steel cable, as coating 112. The first coating 1121 can cover the entire surface of the end face 11A in the longitudinal direction of the steel cable 11 or can cover part of the end face 11A.

[0142] Furthermore, the steel cable 11 can have a second coating 1122 covering the side of the side surface 11B of the steel cable 11, as does the coating 112. The second coating 1122 can cover the entire surface of the side surface 11B of the steel cable 11 or can cover part of the side surface 11B.

[0143] By applying the coating 112 to the surface of the wire 111 of the steel cable 11, the corrosion resistance of the steel cable 11 can be improved compared to the case where only the wire 111 is used.

[0144] When manufacturing the rubber compound using steel cable, it is necessary to cut it to the required size. Therefore, conventional rubber compounds do not have a coating on the end face along the length of the steel cable. Without this coating, corrosion will occur along the length of the steel cable.

[0145] In contrast, the steel cable 11 of this embodiment has the first coating 1121, which covers the end face 11A in the longitudinal direction, thereby increasing the corrosion resistance.

[0146] Furthermore, in this version, the steel cable 11 has the second coating 1122, which covers the side of the side surface 11B, thereby protecting the side surface 11B and increasing corrosion resistance.

[0147] The first coating 1121 can be formed after the steel cable is cut to the predetermined length to produce the rubber complex 10. Specifically, the first coating can be formed after cutting the steel cable 11.

[0148] The specific means for forming the first coating 1121 are not particularly limited, and various means can be used to form a coating with a desired composition. The first coating 1121 can contain one or more elements selected, for example, from oxides and metals. Since the manufacturing process of the first coating 1121 has already been described, its description is omitted here.

[0149] The method for forming the second coating 1122 is not particularly limited. For example, a suitable coating can be formed on the surface of the conductor or base wire to manufacture the steel cable 11, and the conductor can be drawn so that a second coating 122 can be formed on the surface of the wire 11. That is, the second coating 1122, which is located on the side of the side surface 11B of the steel cable 11, originates from the coating that is formed on the surface of the conductor before the wire is drawn.

[0150] The first coating 1121, which is applied to the end face 11A of the steel cable 11, and the second coating 1122, which is applied to the side face 11B, are formed at different times. Therefore, the composition and thickness of the first coating 1121 and the second coating 1122 can be the same or different.

[0151] The compositions of the first coating 1121 and the second coating 1122, which are the coatings 112, are not particularly restricted. The first coating 1121 preferably contains, for example, Cu (copper). This is because the Cu-containing first coating 1121 can protect the end face of the steel cable 11 and increase its corrosion resistance.

[0152] Furthermore, the first coating 1121 may preferably contain Zn (zinc) in addition to Cu.

[0153] Zinc (Zn) exhibits a higher ionization tendency than copper (Cu). Since the second coating 1122 contains Zn in addition to Cu, it can act as sacrificial corrosion protection. Therefore, the end faces 11A in the longitudinal direction of the steel cable 11 are particularly well protected, and the corrosion resistance can be further increased.

[0154] The second coating 1122 further preferably comprises, in addition to Cu and Zn, one or more selected from Sn (tin), Cr (chromium), Fe (iron), Co (cobalt), and Ni (nickel).

[0155] Sn, Cr, Fe, Co, and Ni exhibit greater ionization tendencies than Zn. By additionally comprising Cu and Zn, and furthermore one or more selected elements from Sn, Cr, Fe, Co, and Ni, the second coating 1122 can act as sacrificial corrosion protection, or the synthesis potential or combined potential of Cu and Zn can be increased or enhanced. For this reason, the end faces 11A in the longitudinal direction of the steel cable 11 are particularly well protected, and the corrosion resistance can be further increased.

[0156] A material similar to that of the first coating 1121 can also be suitably used for the second coating 1122. That is, the second coating 1122 preferably contains Cu. Furthermore, it is more preferred that the second coating 1122 also contains Zn in addition to Cu. More preferably, the second coating 1122 also contains, in addition to Cu and Zn, one or more selected from Sn, Cr, Fe, Co, and Ni. The reason is the same as in the case of the first coating 1121, so the explanation will not be repeated.

[0157] In conventional steel cables, the first coating 1121, which is coating 112, is not formed on the end face 11A of the steel cable 11. Therefore, if even a small amount of the first coating 1121 is applied to the end face 11A of the steel cable 11, the corrosion resistance can be improved compared to the prior art, and the extent to which the first coating 1121 is applied is not particularly limited. The first coating 1121 preferably covers 20% or more, and more preferably 40% or more, of the area of ​​the end face 11A in the longitudinal direction of the steel cable 11. It is preferred that if the first coating 1121 covers 20% or more of the area of ​​the end face 11A in the longitudinal direction of the steel cable 11, the corrosion resistance of the end face 11A of the steel cable 11 can be increased.

[0158] The first coating 1121 can also cover the entire end face 11A of the steel cable 11, or the first coating 1121 can cover less than or equal to 100% of the area of ​​the end face 11A of the steel cable 11.

[0159] A method for measuring the proportion of the area where the first coating 1121 covers the end face 11A of the steel cable 11 is not particularly limited. It can be evaluated in the same way as the previously mentioned first coating.

[0160] That is, the rubber complex 10 is first formed, for example, using the steel cable 11 to be evaluated. When the end-face rubber 121, which is at least part of the rubber 12 arranged on the end-face side 11A of the steel cable 11 within the contained rubber complex 10, is removed, the end-face side 11A of the steel cable 11 is exposed, as shown in Fig.Figure 3 shows this. Therefore, it is possible to calculate the proportion of the area occupied by the rubber 12 on the end face 11A of the steel cable 11, excluding the area where the steel cable 11 is exposed, such as the first coating 1121. Since the rubber 12 remaining on the end face 11A of the steel cable 11 corresponds to the section where the first coating 1121 was formed, the proportion of the area where the first coating 1121 covers the end face 11A of the steel cable 11 can be calculated, as described above, according to the proportion of the area occupied by the rubber 12.

[0161] However, the rubber can even be partially removed at the point where the first coating 1121 was formed. Therefore, the proportion of the area where the first coating 1121 covers the end face 11A in the longitudinal direction of the steel cable 11 is greater than or equal to the proportion of the area calculated by the above method.

[0162] Furthermore, the mapping of the element distribution on the end face 11A of the steel cable 11 can be carried out and the proportion of the area where the first coating 112 covers the end face 11A of the steel cable 11 can be calculated.

[0163] In particular, when mapping the element distribution of the end face of the steel cable 11 is performed, the area in which the components of the first coating 1121 are distributed is the area in which the first coating 1121 is formed. Therefore, the area fraction of the region in which the first coating 1121 is formed on the end face 11A of the steel cable 11 can be determined from the result of the element distribution mapping. This allows the calculation of the area fraction in which the first coating 1121 covers the end face 11A of the steel cable 11.

[0164] The means for mapping the element distribution are not particularly limited, and SEM-EDX or similar tools can be used.

[0165] The thickness of the first layer 1121 is not particularly limited, but on average it is preferably greater than or equal to 5 nm and less than or equal to 2 µm, and further preferably greater than or equal to 0.1 µm and less than or equal to 1.5 µm.

[0166] The average thickness of the first coating 1121 is greater than or equal to 5 nm to increase the corrosion resistance of the end face. Even when the rubber complex is formed, the first coating 131 can be applied with sufficient thickness, and the corrosion resistance of the end face can be increased.

[0167] The average thickness of the first coating 1121 is less than or equal to 2 µm, which can increase productivity in the production of the steel cable. If the first coating 1121 is too thick when applied to a rubber compound, the first coating 131 can become porous, and the effect of increasing the corrosion resistance of the end face 11A can be suppressed.

[0168] The method for obtaining the average thickness of the first coating 1121 is not particularly limited, but can, for example, be measured using a fluorescence X-ray film thickness gauge. The measurement is carried out at a total of three locations: the center of the end face 11A of the steel cable 11 and two measuring points on a line segment passing through the center, and the mean of these measurements can be taken as the average thickness of the first coating 1121.

[0169] The line segment passing through the center of the end face 11A of the steel cable 11 is a line segment whose diameter is the circle that forms the contour of the end face 11A. Here, D is the diameter of the circle that forms the contour of the end face 11A. In this case, the two measuring points are two points at a distance of 0.25 D from the center point on the line segment that is arbitrarily drawn through the first coating 1121 on the end face 11A and whose diameter is the circle that forms the contour of the end face 11A.

[0170] Although the embodiments have been described in detail above, the embodiments are not limited to the specific embodiments, and various modifications and changes can be made within the scope of protection of the claims. [Examples of implementation]

[0171] Specific examples are described below, but the present invention is not limited to these examples. (Evaluation method)

[0172] The evaluation method for the rubber complex produced in the following experimental example is described. (1) Assessment of the corrosion resistance of the rubber complex

[0173] With regard to the rubber complex 10 produced in each of the following experimental examples, when the rubber 121 was removed from the side of the end face 11A of the steel cable 11, the corrosion resistance was evaluated by the area fraction occupied by the rubber 12 in the end face 11A in the longitudinal direction of the steel cable 11.

[0174] During the evaluation, a boundary line was visually identified in the image of the side of end face 11A in the longitudinal direction of the steel cable 11 after the rubber 121 had been removed from the end face. This boundary line separated the area where the rubber remained from the area where the first coating 1121, or end face 11A, was exposed in the longitudinal direction of the steel cable 11. Additionally, the contour line of end face 11A was also drawn. The boundary line and the contour line of end face 11A are lines that surround the area where the rubber remains. The area of ​​the area where the rubber 12 remains was then calculated by dividing the area containing the rubber 12 (enclosed by the boundary line and the contour line of end face 11A) and any other areas using a binary operation.

[0175] Subsequently, the percentage of the area occupied by the rubber 12 in an end face in the longitudinal direction of an arbitrary steel cable in the rubber complex was determined.

[0176] It was rated as “A” if the area fraction of the rubber 12 in the end face in the longitudinal direction of the steel cable is greater than or equal to 80%; as "B" if it is greater than or equal to 60% and less than 80%; as “C” if it is greater than or equal to 20% and less than 60%; and as "D" if it is less than 20%.

[0177] In each of the following experimental examples 1-1 to 1-10, two rubber complexes were prepared for evaluation. One of the two rubber complexes was then evaluated for corrosion resistance immediately after preparation (initial evaluation). The other of the two rubber complexes was evaluated for the above corrosion resistance after being subjected to a humidity and heat resistance test. In the humidity and heat resistance test, the rubber complex was kept in an environment with a temperature of 80°C and a relative humidity of 95% for 150 hours (humidity and heat resistance evaluation).

[0178] In both the initial assessment and the moisture and heat resistance assessment, A is the best and B, C and D are worse in that order.

[0179] When the rubber is removed, the rubber remaining on the end face of the steel cable corresponds to the area where the coating is formed. Therefore, the higher the results of the moisture and heat resistance rating after the moisture and heat resistance test, the more likely it is that the end face of the steel cable will be protected by the stable coating even after the moisture and heat resistance test, and that the rubber compound will remain, suppressing corrosion of the steel cable end faces.

[0180] As shown in Table 1, there is a correlation between the initial assessment and the moisture and heat resistance assessment. If the result of the initial assessment is excellent, it can be determined that the rubber complex is responsible for suppressing corrosion of the steel cable end faces. Therefore, starting with experimental example 2, only the initial assessment was performed.

[0181] In the initial assessment, when the rubber is removed, the portion where the rubber remains on the end face of the steel cable corresponds to the portion where at least the first coating 1121 is formed. Therefore, it can also be stated that the result of the initial assessment shows the area fraction of the surface where at least the first coating 1121 is formed on the end face in the longitudinal direction of the steel cable. (2) Assessment of the corrosion resistance of the steel cable

[0182] Electrochemical measurements (LSV: Linear Sweep Voltammetry) were used for the evaluation. Specifically, the evaluation sample was immersed in an aqueous sulfuric acid solution with pH 1 and the current flowing at 0 V was observed (reference electrode: Ag / AgCl, counter electrode: Pt).

[0183] To easily verify the effect of the ends, 30 steel cables manufactured under the same conditions were bundled for the evaluation sample and immersed up to 10 mm from the end face on which the first coating is formed in the aforementioned aqueous sulfuric acid solution, and the aforementioned current was measured.

[0184] The current value with respect to the steel cable, which in the following Experimental Example 1-1 (provision of the steel cable) are produced and before the coating is formed on the end face, was measured using the above-mentioned measuring method, i.e. the corrosion current, was 10 mA / cm². 2 .

[0185] Therefore, a measured current value of less than 10 mA / cm² means 2 excellent corrosion resistance, while a current value greater than or equal to 10 mA / cm 2 This means poor corrosion resistance. (Experimental examples)

[0186] The experimental conditions are explained below. [Experimental Example 1]

[0187] Rubber complexes and steel cables were manufactured according to the following process, and their corrosion resistance was evaluated. Experimental examples 1-1 to 1-9 are embodiments, and experimental example 1-10 is a comparative example. (Experimental Example 1-1)(Provision of the steel cable)

[0188] A copper layer and a zinc layer were formed on the surface of the steel filament by plating. The copper layer was plated using copper pyrophosphate as the plating solution at a current density of 22 A / dm². 2 and deposited within a process time of 14 seconds. The zinc layer was deposited using zinc sulfate as the plating solution at a current density of 20 A / dm². 2 and separated in a process time of 7 seconds.

[0189] Subsequently, a heat treatment was carried out by heating to 600°C for 9 seconds in an atmospheric environment to diffuse the metal components and form the coating.

[0190] By pulling the filament on which the obtained coating was formed, a cable diameter of 1 mm was obtained.

[0191] The drawn steel cable was then cut lengthwise at several points to the size of the rubber complex to be produced. The resulting steel cable has the second coating 1122, which covers side 11B and is formed from the coating of the filament described above. The second coating 1122 was examined using SEM-EDX and was found to contain Cu and Zn.

[0192] Part of the recovered steel cable was used to manufacture the rubber complex described below, and the remainder was used to manufacture the steel cable described below. (Provision of the rubber composition)

[0193] A rubber compound was produced containing rubber components and additives. The rubber compound contains 100 parts by mass of natural rubber as the rubber component. The rubber compound then contains, as additives (based on 100 parts by mass of the rubber component), 60 parts by mass of carbon black, 6 parts by mass of sulfur, 1 part by mass of vulcanizing agent, 10 parts by mass of zinc oxide, and 1 part by mass of cobalt stearate as organic cobalt salts. (Provision of the rubber complex).

[0194] A in Fig. 1 and Fig. 2 The rubber complex 10 shown was produced using the above-mentioned steel cable and rubber composition.

[0195] The steel cables 11 were arranged so that their longitudinal directions were parallel to each other. Furthermore, the side surface 11B of the steel cable 11 was covered with the rubber composition to produce a starting material for the rubber complex. The end faces 11A in the longitudinal direction of the steel cable 11 were left exposed without being covered with the rubber composition.

[0196] In the starting material of the rubber complex, a resin mask with a thickness of 15 µm was placed on the side of the end face 11A in the longitudinal direction of the steel cable 11 to protect the rubber composition. The resin mask has an opening at a location corresponding to the end face 11A in the longitudinal direction of the steel cable 11, so that the end face 11A is exposed without being covered by the resin mask.

[0197] The exposed end face 11A in the longitudinal direction of the steel cable 11 were then pretreated.

[0198] Pretreatment consisted of electrolytic degreasing with 20 wt% sulfuric acid, followed by rinsing, electrolytic degreasing with 10 wt% sodium hydroxide solution, rinsing, immersion in 1 wt% sulfuric acid, and rinsing in this order. The electrolytic degreasing with 20 wt% sulfuric acid was carried out at a liquid temperature of 45°C with a current density of 10 A / dm³. 2 The electrolytic degreasing process, using 10% sodium hydroxide by mass, was carried out at a liquid temperature of 40°C with a current density of 10 A / dm². 2 The immersion was carried out for 1 second. The immersion in 1% sulfuric acid was performed at a liquid temperature of 35°C for 1 second.

[0199] Then, a first coating was formed on the end face 11A in the longitudinal direction of the steel cable 11 using the paint-on method. Specifically, a conductive copper nano-ink (model number GO-01), manufactured by Ishihara Chemical Co., Ltd., was applied to the entire end face 11A in the longitudinal direction of the steel cable 11 and dried to form a first coating 1121 with a thickness of 0.15 µm.

[0200] The aforementioned first coating 1121 was formed under the same conditions onto the end faces 11A on both sides along the longitudinal direction of all steel cables 11 in the rubber complex. Furthermore, the average thickness of the first coating 1121, formed on the end face 11A along the longitudinal direction of the steel cable 11, was measured and confirmed to be 0.15 µm.

[0201] The average thickness of the first coating 1121 was measured using an X-ray fluorescence coating thickness gauge. The thickness was measured at the center of the end face 11A of the steel cable 11 and at two measuring points on a line segment passing through the center, and their average value was taken to be the average thickness of the first coating 1121.

[0202] The line segment passing through the center of the end face 11A of the above steel cable 11 is a line segment that is the diameter of the circle representing the contour line of the end face 11A. If the diameter of the circle representing the contour line of the end face 11A is D, the two measurement points above are two points spaced 0.25 D apart from the center point on the line segment that is the diameter of the circle representing the contour line of the end face 11A, the line segment being arbitrarily set to pass over the first coating 1121 on the end face 11A. The average thickness of the first coating 1121 was measured in the same way in the following experimental examples.

[0203] After the conductive copper nano-ink above had been applied and dried, the resin mask protecting the rubber compound was removed. The rubber compound was also applied to the end face 11A of the steel cable 11 in the longitudinal direction of the rubber compound.

[0204] Vulcanization was then carried out at 180°C for 10 minutes to obtain a rubber complex 10. In the resulting rubber complex 10, the rubber 12 was arranged to cover the entire surface of the steel cable 11. A first coating 131, containing copper and sulfur, was applied to the end face 11A along the longitudinal side of the steel cable 11. A second coating 132, containing copper, zinc, and sulfur, was applied to the side face 11B of the steel cable 11. The end face 11A and the side face 11B of the steel cable 11 were bonded to the rubber 12 by the first coating 131 and the second coating 132, respectively.

[0205] SEM-EDX analysis confirmed that the first coating 131 contains Cu and S, and that the second coating 132 contains Cu, Zn, and S. The same analysis was performed in the following experimental examples 1-2 to 1-10 to identify the components present. Since the second coating 132 also contains Cu, Zn, and S in the following other experimental examples, its description is omitted. Furthermore, in the following experimental examples 1-2 to 1-9, experimental example 2, and experimental example 3, both the first coating 131 and the second coating 132 contain at least Cu and S, thus constituting a copper-sulfur compound.

[0206] Using the obtained rubber complex 10, the corrosion resistance of the rubber complex was evaluated. The evaluation results are shown in Table 1.

[0207] As shown in the evaluation results, it was confirmed that the rubber remained after removing the end-face rubber 121 to assess the corrosion resistance of the side of end face 11A in the longitudinal direction of the steel cable 11. Therefore, it can be concluded that the end face 11A of the steel cable 11 is bonded to the rubber 12 via the first covering 131, as described above. After removing the rubber from the side face 11B of the steel cable 11, it was confirmed that the rubber 12 similarly remains on the side face 11B of the steel cable 11. Therefore, it can be concluded that the side face 11B of the steel cable 11 is bonded to the rubber 12 via the second covering 132.

[0208] In the following experimental examples 1-2 to 1-9, for the same reasons it was confirmed that the end face 11A and the side face 11B of the steel cable 11 are held in place by the first covering 131 and the second covering 132 respectively on the rubber. (Manufacturing of the steel cable)

[0209] The end face 11A in the longitudinal direction of the steel cable, obtained during the preparation of the steel cable in experimental example 1-1, was pretreated in the same manner as during the preparation of the rubber complex in that experimental example, and then the first coating 1121 was formed. Analysis by SEM-EDX confirmed that the first coating 1121 contained Cu. Furthermore, the average thickness of the first coating was 0.15 µm.

[0210] Regarding the steel cables received, the corrosion resistance was assessed, and the current was less than 10 mA / cm.2 . (Experimental Example 1-2) (Production of the rubber complex)

[0211] The rubber complex 10 was prepared and evaluated in the same manner as in experimental example 1-1, except that the first coating 1121 on the entire end face 11A in the longitudinal direction of the steel cable 11 was formed by electroplating under the following conditions.

[0212] In this experimental example, the first coating 1121 was a stacked coating, in which Cu layers and Sn layers were stacked in that order on the end face 11A. The first coating 1121 was shaped such that the total layer thickness of the Cu and Sn layers was 0.15 µm. The average thickness of the first coating 1121 on the end face 11A in the longitudinal direction of the steel cable 11 was measured and confirmed to be 0.15 µm.

[0213] The copper layers were formed using a copper plating solution in a pyrophosphate bath. The tin layers were formed using a tin plating solution, which is a sulfuric acid bath. During the formation of each layer, an electrode with a sponge soaked in a plating solution was brought into contact with the end face 11A along the longitudinal side of the steel cable 11, on which the first coating 1121 was being formed. Electric current was supplied from the end face opposite end face 11A along the longitudinal side of the steel cable 11, on which the first coating 1121 was being formed. The thickness of the first coating 1121 was adjusted according to the amount of electricity supplied.

[0214] After the first coating 1121 was formed, it was washed with water and dried, and then the resin mask protecting the rubber composition was removed. The rubber composition was then also applied to the side of the end face 11A in the longitudinal direction of the steel cable 11 in the starting material of the rubber complex and vulcanized under the same conditions as in experimental example 1-1 to obtain the rubber complex 10.

[0215] In the rubber complex 10 obtained, the rubber 12 was arranged to cover the entire surface of the steel cable 11. A first coating 131, containing Cu, Sn, and S, was applied to the end face 11A along the longitudinal side of the steel cable 11. A second coating 132 was applied to the side face 11B of the steel cable 11. The end face 11A and the side face 11B of the steel cable 11 were bonded to the rubber 12 by the first coating 131 and the second coating 132, respectively. The evaluation results are shown in Table 1. (Manufacturing of the steel cable)

[0216] The end face 11A in the longitudinal direction of the steel cable, obtained during the preparation of the steel cable in experimental example 1-1, was pretreated in the same manner as during the preparation of the rubber complex in that experimental example, and then the first coating 1121 was formed. Analysis by SEM-EDX confirmed that the first coating 1121 contained Cu and Sn. Furthermore, the average thickness of the first coating was 0.15 µm.

[0217] Regarding the steel cables received, the corrosion resistance was assessed, and the current was less than 10 mA / cm. 2 . (Experimental Example 1-3) (Production of the rubber complex)

[0218] The rubber complex 10 was prepared and evaluated in the same manner as in experimental example 1-1, except that the first coating 1121 on the entire end face 11A in the longitudinal direction of the steel cable 11 was formed by electroplating under the following conditions.

[0219] In this experimental example, the first coating 1121 was a stacked coating in which Cu layers, Zn layers, and Sn layers were stacked in that order on the end face 11A. The first coating 1121 was shaped such that the thickness of the Cu layers : thickness of the Zn layers : thickness of the Sn layers = 3:4:3, and that the total thickness of the Cu and Sn layers was 0.15 µm. The average thickness of the first coating 1121 on the end face 11A in the longitudinal direction of the steel cable 11 was measured and confirmed to be 0.15 µm.

[0220] The copper layers were formed using a copper plating solution in a pyrophosphate bath. The zinc layers were formed using a zinc plating solution in a boron fluoride bath. During the formation of each layer, an electrode with a sponge impregnated with a plating solution was brought into contact with the end face 11A along the longitudinal side of the steel cable 11, on which the first coating 1121 was being formed. Electric current was supplied from the end face opposite end face 11A along the longitudinal side of the steel cable 11, on which the first coating 1121 was being formed. The thickness of the first coating 1121 was adjusted according to the amount of electricity supplied.

[0221] After the first coating 1121 was formed, it was washed with water and dried, and then the resin mask protecting the rubber composition was removed. The rubber composition was then also applied to the side of the end face 11A in the longitudinal direction of the steel cable 11 in the starting material of the rubber complex and vulcanized under the same conditions as in experimental example 1-1 to obtain the rubber complex 10.

[0222] In the rubber complex 10 obtained, the rubber 12 was arranged to cover the entire surface of the steel cable 11. A first coating 131, containing Cu, Zn, and S, was applied to the end face 11A along the longitudinal side of the steel cable 11. A second coating 132 was applied to the side face 11B of the steel cable 11. The end face 11A and the side face 11B of the steel cable 11 were bonded to the rubber 12 by the first coating 131 and the second coating 132, respectively. The evaluation results are shown in Table 1. (Manufacturing of the steel cable)

[0223] The end face 11A in the longitudinal direction of the steel cable, obtained during the preparation of the steel cable in experimental example 1-1, was pretreated in the same manner as during the preparation of the rubber complex in this experimental example, and then the first coating 1121 was formed. Analysis by SEM-EDX confirmed that the first coating 1121 contained Cu and Zn. Furthermore, the average thickness of the first coating was 0.15 µm.

[0224] Regarding the steel cables received, the corrosion resistance was assessed, and the current was less than 10 mA / cm. 2 . (Experimental Example 1-4) (Production of the rubber complex)

[0225] The rubber complex 10 was prepared and evaluated in the same manner as in experimental example 1-1, except that the first coating 1121 on the entire end face 11A in the longitudinal direction of the steel cable 11 was formed by electroplating under the following conditions.

[0226] In this experimental example, the first coating 1121 was a stacked coating in which Cu layers and Zn layers were stacked on the end face 11A in that order. The first coating 1121 was shaped such that the thickness of the Cu layers was : thickness of the Zn layers = 6:4, and that the total thickness of the Cu and Sn layers was 0.15 µm. The average thickness of the first coating 1121, applied to the end face 11A in the longitudinal direction of the steel cable 11, was measured and confirmed to be 0.15 µm.

[0227] The copper layers were formed using a copper plating solution in a pyrophosphate bath. The zinc layers were formed using a zinc plating solution in a boron fluoride bath. During the formation of each layer, an electrode with a sponge impregnated with a plating solution was brought into contact with the end face 11A along the longitudinal side of the steel cable 11, on which the first coating 1121 was being formed. Electric current was supplied from the end face opposite end face 11A along the longitudinal side of the steel cable 11, on which the first coating 1121 was being formed. The thickness of the first coating 1121 was adjusted according to the amount of electricity supplied.

[0228] After the first coating 1121 was formed, it was washed with water and dried, and then the resin mask protecting the rubber composition was removed. The rubber composition was then also applied to the side of the end face 11A in the longitudinal direction of the steel cable 11 in the starting material of the rubber complex and vulcanized under the same conditions as in experimental example 1-1 to obtain the rubber complex 10.

[0229] In the rubber complex 10 obtained, the rubber 12 was arranged to cover the entire surface of the steel cable 11. A first coating 131, containing Cu, Zn, and S, was applied to the end face 11A along the longitudinal side of the steel cable 11. A second coating 132 was applied to the side face 11B of the steel cable 11. The end face 11A and the side face 11B of the steel cable 11 were bonded to the rubber 12 by the first coating 131 and the second coating 132, respectively. The evaluation results are shown in Table 1. (Manufacturing of the steel cable)

[0230] The end face 11A in the longitudinal direction of the steel cable, obtained during the preparation of the steel cable in experimental example 1-1, was pretreated in the same manner as during the preparation of the rubber complex in that experimental example, and then the first coating 1121 was formed. Analysis by SEM-EDX confirmed that the first coating 1121 contained Cu and Zn. Furthermore, the average thickness of the first coating was 0.15 µm.

[0231] Regarding the steel cables received, the corrosion resistance was assessed, and the current was less than 10 mA / cm. 2 . (Experimental Example 1-5) (Production of the rubber complex)

[0232] The rubber complex 10 was prepared and evaluated in the same manner as in experimental example 1-1, except that the first coating 1121 on the entire end face 11A in the longitudinal direction of the steel cable 11 was formed by electroplating under the following conditions.

[0233] In this experimental example, the first coating 1121 was a copper layer and was shaped to have a layer thickness of 0.15 µm. The average thickness of the first coating 1121, applied to the end face 11A in the longitudinal direction of the steel cable 11, was measured and confirmed to be 0.15 µm.

[0234] The copper layers, which constituted the first coating 1121, were formed using a copper plating solution in a pyrophosphate bath. During the formation of the copper layer, an electrode with a sponge impregnated with a plating solution was brought into contact with the end face 11A along the longitudinal axis of the steel cable 11, on which the first coating 1121 was formed. Electric current was supplied from the end face opposite end face 11A along the longitudinal axis of the steel cable 11, on which the first coating 1121 was formed. The thickness of the first coating 1121 was adjusted according to the amount of electricity supplied.

[0235] After the first coating 1121 was formed, it was washed with water and dried, and then the resin mask protecting the rubber composition was removed. The rubber composition was then also applied to the side of the end face 11A in the longitudinal direction of the steel cable 11 in the starting material of the rubber complex and vulcanized under the same conditions as in experimental example 1-1 to obtain the rubber complex 10.

[0236] In the rubber complex 10 obtained, the rubber 12 was arranged to cover the entire surface of the steel cable 11. A first coating 131, containing Cu and S, was applied to the end face 11A along the longitudinal side of the steel cable 11. A second coating 132 was applied to the side face 11B of the steel cable 11. The end face 11A and the side face 11B of the steel cable 11 were bonded to the rubber 12 by the first coating 131 and the second coating 132, respectively. The evaluation results are shown in Table 1. (Manufacturing of the steel cable)

[0237] The end face 11A in the longitudinal direction of the steel cable, obtained during the preparation of the steel cable in experimental example 1-1, was pretreated in the same manner as during the preparation of the rubber complex in this experimental example, and then the first coating 1121 was formed. Analysis by SEM-EDX confirmed that the first coating 1121 contained Cu. Furthermore, the average thickness of the first coating was 0.15 µm.

[0238] Regarding the steel cables received, the corrosion resistance was assessed, and the current was less than 10 mA / cm. 2 . (Experimental Example 1-6) (Production of the rubber complex)

[0239] The rubber complex 10 was prepared and evaluated in the same manner as in experimental example 1-1, except that the first coating 1121 on the entire end face 11A in the longitudinal direction of the steel cable 11 was formed by electroplating under the following conditions.

[0240] In this experimental example, the first coating 1121 was a copper layer and was shaped to have a layer thickness of 0.15 µm. The average thickness of the first coating 1121, applied to the end face 11A in the longitudinal direction of the steel cable 11, was measured and confirmed to be 0.15 µm.

[0241] The first coating 1121 was shaped such that the end face in the longitudinal direction of the steel cable 11 was immersed in a sulfuric acid bath, which was adjusted to contain 0.01 mol / dm3 copper sulfate, for 1 minute, then rinsed and dried.

[0242] After forming the first coating 1121, the resin mask protecting the rubber compound was removed. The rubber compound was also applied to the end face 11A of the steel cable 11 in the longitudinal direction of the rubber compound. The rubber compound 10 was obtained by vulcanization under the same conditions as in Example 1-1.

[0243] In the rubber complex 10 obtained, the rubber 12 was arranged to cover the entire surface of the steel cable 11. A first coating 131, containing Cu and S, was applied to the end face 11A along the longitudinal side of the steel cable 11. A second coating 132 was applied to the side face 11B of the steel cable 11. The end face 11A and the side face 11B of the steel cable 11 were bonded to the rubber 12 by the first coating 131 and the second coating 132, respectively. The evaluation results are shown in Table 1. (Manufacturing of the steel cable)

[0244] The end face 11A in the longitudinal direction of the steel cable, obtained during the preparation of the steel cable in experimental example 1-1, was pretreated in the same manner as during the preparation of the rubber complex in this experimental example, and then the first coating 1121 was formed. Analysis by SEM-EDX confirmed that the first coating 1121 contained Cu. Furthermore, the average thickness of the first coating was 0.15 µm.

[0245] Regarding the steel cables received, the corrosion resistance was assessed, and the current was less than 10 mA / cm. 2 . (Experimental Example 1-7) (Production of the rubber complex)

[0246] The rubber complex 10 was prepared and evaluated in the same manner as in experimental example 1-1, except that the first coating 1121 on the entire end face 11A in the longitudinal direction of the steel cable 11 was formed by electroplating under the following conditions.

[0247] In this experimental example, the first coating 1121 was a Cu-Zn alloy layer and was shaped to have a layer thickness of 0.15 µm. The average thickness of the first coating 1121, applied to the end face 11A in the longitudinal direction of the steel cable 11, was measured and confirmed to be 0.15 µm.

[0248] The Cu-Zn alloy layer, which constituted the first coating 1121, was formed using a plating solution added to a pyrophosphate bath for copper plating with zinc sulfate and L-histidine hydrochloride hydrate, which was an additive. The Cu-Zn alloy layer was prepared such that the molar ratio of Cu and Zn was Cu:Zn = 6:4. During the formation of the Cu-Zn alloy layer, an electrode with a sponge impregnated with a plating solution was brought into contact with the end face 11A in the longitudinal direction of the steel cable 11 on which the first coating 1121 was formed. Electric current was supplied from the end face opposite end face 11A in the longitudinal direction of the steel cable 11 on which the first coating 1121 was formed. The thickness of the first coating 1121 was adjusted according to the amount of electricity supplied.

[0249] After the first coating 1121 was formed, it was washed with water and dried, and then the resin mask protecting the rubber composition was removed. The rubber composition was then also applied to the side of the end face 11A in the longitudinal direction of the steel cable 11 in the starting material of the rubber complex and vulcanized under the same conditions as in experimental example 1-1 to obtain the rubber complex 10.

[0250] In the rubber complex 10 obtained, the rubber 12 was arranged to cover the entire surface of the steel cable 11. A first coating 131, containing Cu, Zn, and S, was applied to the end face 11A along the longitudinal side of the steel cable 11. A second coating 132 was applied to the side face 11B of the steel cable 11. The end face 11A and the side face 11B of the steel cable 11 were bonded to the rubber 12 by the first coating 131 and the second coating 132, respectively. The evaluation results are shown in Table 1. (Manufacturing of the steel cable)

[0251] The end face 11A in the longitudinal direction of the steel cable, obtained during the preparation of the steel cable in experimental example 1-1, was pretreated in the same manner as during the preparation of the rubber complex in this experimental example, and then the first coating 1121 was formed. Analysis by SEM-EDX confirmed that the first coating 1121 contained Cu, Zn. Furthermore, the average thickness of the first coating was 0.15 µm.

[0252] Regarding the steel cables received, the corrosion resistance was assessed, and the current was less than 10 mA / cm. 2 . (Experimental Example 1-7) (Production of the rubber complex)

[0253] The rubber complex 10 was prepared and evaluated in the same manner as in experimental example 1-1, except that the first coating 1121 on the entire end face 11A in the longitudinal direction of the steel cable 11 was formed by electroplating under the following conditions.

[0254] In this experimental example, the first coating 1121 was a Cu-Sn alloy layer and was shaped to have a layer thickness of 0.15 µm. The average thickness of the first coating 1121, applied to the end face 11A in the longitudinal direction of the steel cable 11, was measured and confirmed to be 0.15 µm.

[0255] The Cu-Sn alloy layer, which constituted the first coating 1121, was formed using a plating solution added to a pyrophosphate bath for copper plating with tin sulfate and L-histidine hydrochloride hydrate, which was an additive. The Cu-Sn alloy layer was prepared such that the molar ratio of Cu and Sn was Cu:Zn = 95:5. During the formation of the Cu-Sn alloy layer, an electrode with a sponge impregnated with a plating solution was brought into contact with the end face 11A in the longitudinal direction of the steel cable 11 on which the first coating 1121 was formed. Electric current was supplied from the end face opposite end face 11A in the longitudinal direction of the steel cable 11 on which the first coating 1121 was formed. The thickness of the first coating 1121 was adjusted according to the amount of electricity supplied.

[0256] After the first coating 1121 was formed, it was washed with water and dried, and then the resin mask protecting the rubber composition was removed. The rubber composition was then also applied to the side of the end face 11A in the longitudinal direction of the steel cable 11 in the starting material of the rubber complex and vulcanized under the same conditions as in experimental example 1-1 to obtain the rubber complex 10.

[0257] In the rubber complex 10 obtained, the rubber 12 was arranged to cover the entire surface of the steel cable 11. A first coating 131, containing Cu, Sn, and S, was applied to the end face 11A along the longitudinal side of the steel cable 11. A second coating 132 was applied to the side face 11B of the steel cable 11. The end face 11A and the side face 11B of the steel cable 11 were bonded to the rubber 12 via the first coating 131 and the second coating 132, respectively. The evaluation results are shown in Table 1. (Manufacturing of the steel cable)

[0258] The end face 11A in the longitudinal direction of the steel cable, obtained during the preparation of the steel cable in experimental example 1-1, was pretreated in the same manner as during the preparation of the rubber complex in this experimental example, and then the first coating 1121 was formed. Analysis by SEM-EDX confirmed that the first coating 1121 contained Cu, Sn. Furthermore, the average thickness of the first coating was 0.15 µm.

[0259] Regarding the steel cables received, the corrosion resistance was assessed, and the current was less than 10 mA / cm. 2 . (Experimental Example 1-6) (Production of the rubber complex)

[0260] The rubber complex 10 was prepared and evaluated in the same manner as in experimental example 1-1, except that the first coating 1121 on the entire end face 11A in the longitudinal direction of the steel cable 11 was formed by electroplating under the following conditions.

[0261] In this experimental example, the first coating 1121 was a Cu-Sn alloy layer, and the first coating 1121 was shaped such that the layer thickness was 0.15 µm. The average thickness of the first coating 1121, applied to the end face 11A in the longitudinal direction of the steel cable 11, was measured and confirmed to be 0.15 µm.

[0262] The Cu-Sn alloy layer, which is the first coating 1121, was formed such that the end face in the longitudinal direction of the steel cable 11 was immersed in a sulfuric acid bath containing copper and tin for 20 seconds, then rinsed and dried. The Cu-Sn alloy layer was prepared such that the molar ratio of Cu and Sn was Cu:Zn = 95:5.

[0263] After forming the first coating 1121, the resin mask protecting the rubber compound was removed. The rubber compound was also applied to the end face 11A of the steel cable 11 in the longitudinal direction of the starting material of the rubber complex 10. The rubber complex 10 was obtained by vulcanization under the same conditions as in Example 1-1.

[0264] In the rubber complex 10 obtained, the rubber 12 was arranged to cover the entire surface of the steel cable 11. A first coating 131, containing Cu, Sn, and S, was applied to the end face 11A along the longitudinal side of the steel cable 11. A second coating 132 was applied to the side face 11B of the steel cable 11. The end face 11A and the side face 11B of the steel cable 11 were bonded to the rubber 12 via the first coating 131 and the second coating 132, respectively. The evaluation results are shown in Table 1. (Manufacturing of the steel cable)

[0265] The end face 11A in the longitudinal direction of the steel cable, obtained during the preparation of the steel cable in experimental example 1-1, was pretreated in the same manner as during the preparation of the rubber complex in this experimental example, and then the first coating 1121 was formed. Analysis by SEM-EDX confirmed that the first coating 1121 contained Cu, Sn. Furthermore, the average thickness of the first coating was 0.15 µm.

[0266] Regarding the steel cables received, the corrosion resistance was assessed, and the current was less than 10 mA / cm. 2 . (Experimental Example 1-10) (Production of the rubber complex)

[0267] In the manufacture of the steel cable, the drawn steel cable was cut at several points along its length to the size of the rubber complex to be produced. Then, the steel cable, which did not have a first coating 1121 formed on its end face, was used. The rubber complex was produced in the same way as in Example 1-1, except for the points mentioned above.

[0268] In the rubber complex 10 obtained, the rubber 12 was arranged to cover the entire surface of the steel cable 11. A second coating 132 was applied to the side surface 11B of the steel cable 11. However, no first coating was formed longitudinally on the end surface 11A of the steel cable 11. The evaluation results are shown in Table 1. (Manufacturing of the steel cable)

[0269] Regarding the steel cable obtained by manufacturing the steel cable in Example 1-1, the corrosion resistance of the steel cable was assessed, and the current was less than 10 mA / cm. 2 . [Table 1] Initial assessment Moisture and heat assessment Example 1-1 A A Example 1-2 A B Examples 1-3 B B Examples 1-4 C C Examples 1-5 A B Examples 1-6 C C Examples 1-7 A A Examples 1-8 B B Examples 1-9 A A Example 1-10 D D

[0270] According to the results shown in Table 1, it was confirmed that in experimental examples 1-1 to 1-9, both the initial rating and the wet-heat rating were A to C, and that the initial rating and the wet-heat rating were almost identical. On the other hand, it was confirmed that in experimental example 1-10, both the initial rating and the wet-heat rating were D, and that no second coating was formed, and the corrosion resistance was worse than that of experimental examples 1-1 to 1-9.

[0271] In Examples 1-1 to 1-9, after the moisture and heat assessment was carried out, the rubber remaining on the end face 11A was removed and the condition of the end face 11A was visually confirmed. It was then confirmed that the area where the rubber remained after the end-face rubber 121 was removed for the moisture and heat assessment was not discolored. That is, it was confirmed that the area where the first covering 131 had formed was protected and could be preserved from corrosion.

[0272] On the other hand, in example 1-10, the humidity and heat assessment confirmed that the entire end face 11A was discolored and corroded, as almost no rubber remained on the end face 11A and the first coating 131 was not formed.

[0273] The above results confirmed that by providing a coating on the end face in the longitudinal direction of the steel cable, the covering on the end face in the longitudinal direction of the steel cable was formed when it became a rubber composite material, and that the corrosion resistance was improved.

[0274] Furthermore, it was confirmed that even if the steel cable did not become a rubber complex, corrosion resistance could be improved by providing a coating on the end face in the longitudinal direction as in experimental examples 1-1 to 1-9. [Experimental Example 2]

[0275] Rubber complexes were manufactured according to the following process and their corrosion resistance was evaluated. Experimental examples 2-1 to 2-5 are embodiments. (Experimental Example 2-1)

[0276] When the first coating 1121 is formed on the entire end face 11A in the longitudinal direction of the steel cable 11, which is contained in the rubber complex starting material, using the coating method, the conductive copper nano-ink, which is the same coating liquid as in Example 1-1, was applied such that the thickness of the first coating 1121 after drying was 0.05 µm. The average thickness of the first coating 1121 on the end face 11A in the longitudinal direction of the steel cable 11 was measured and confirmed to be 0.05 µm.

[0277] The rubber complex was prepared in the same manner as in Example 1-1, except for the points mentioned above.

[0278] In the rubber complex 10 obtained, the rubber 12 was arranged to cover the entire surface of the steel cable 11. A first coating 131, containing Cu and S, was applied to the end face 11A along the longitudinal side of the steel cable 11. A second coating 132 was applied to the side face 11B of the steel cable 11. The end face 11A and the side face 11B of the steel cable 11 were bonded to the rubber 12 by the first coating 131 and the second coating 132, respectively. The evaluation results are shown in Table 2.

[0279] SEM-EDX analysis confirmed that the first coating contained Cu and S. The same analysis was performed in the following examples 2-2 to 2-5 and example 3 to identify the components present. (Experimental Example 2-2)

[0280] When the first coating 1121 is formed on the entire end face 11A in the longitudinal direction of the steel cable 11, which is contained in the rubber complex starting material, using the application method, the conductive copper nano-ink, which is the same coating liquid as in Example 1-1, was applied such that the thickness of the first coating 1121 after drying was 0.1 µm. The average thickness of the first coating 1121 on the end face 11A in the longitudinal direction of the steel cable 11 was measured and confirmed to be 0.1 µm.

[0281] The rubber complex was prepared in the same manner as in Example 1-1, except for the points mentioned above.

[0282] In the rubber complex 10 obtained, the rubber 12 was arranged to cover the entire surface of the steel cable 11. A first coating 131, containing Cu and S, was applied to the end face 11A along the longitudinal side of the steel cable 11. A second coating 132 was applied to the side face 11B of the steel cable 11. The end face 11A and the side face 11B of the steel cable 11 were bonded to the rubber 12 by the first coating 131 and the second coating 132, respectively. The evaluation results are shown in Table 2. (Experimental Example 2-3)

[0283] When the first coating 1121 is formed on the entire end face 11A in the longitudinal direction of the steel cable 11, which is contained in the rubber complex starting material, using the application method, the conductive copper nano-ink, which is the same coating liquid as in Example 1-1, was applied such that the thickness of the first coating 1121 after drying was 0.5 µm. The average thickness of the first coating 1121 on the end face 11A in the longitudinal direction of the steel cable 11 was measured and confirmed to be 0.5 µm.

[0284] The rubber complex was prepared in the same manner as in Example 1-1, except for the points mentioned above.

[0285] In the rubber complex 10 obtained, the rubber 12 was arranged to cover the entire surface of the steel cable 11. A first coating 131, containing Cu and S, was applied to the end face 11A along the longitudinal side of the steel cable 11. A second coating 132 was applied to the side face 11B of the steel cable 11. The end face 11A and the side face 11B of the steel cable 11 were bonded to the rubber 12 by the first coating 131 and the second coating 132, respectively. The evaluation results are shown in Table 2. (Experimental Example 2-4)

[0286] When the first coating 1121 is formed on the entire end face 11A in the longitudinal direction of the steel cable 11, which is contained in the starting material of the rubber complex, using the application method, the conductive copper nano-ink, which is the same coating liquid as in Example 1-1, was applied such that the thickness of the first coating 1121 after drying was 1 µm. The average thickness of the first coating 1121 on the end face 11A in the longitudinal direction of the steel cable 11 was measured and confirmed to be 1 µm.

[0287] The rubber complex was prepared in the same manner as in Example 1-1, except for the points mentioned above.

[0288] In the rubber complex 10 obtained, the rubber 12 was arranged to cover the entire surface of the steel cable 11. A first coating 131, containing Cu and S, was applied to the end face 11A along the longitudinal side of the steel cable 11. A second coating 132 was applied to the side face 11B of the steel cable 11. The end face 11A and the side face 11B of the steel cable 11 were bonded to the rubber 12 by the first coating 131 and the second coating 132, respectively. The evaluation results are shown in Table 2. (Experimental Example 2-5)

[0289] When the first coating 1121 is formed on the entire end face 11A in the longitudinal direction of the steel cable 11, which is contained in the rubber complex starting material, using the application method, the conductive copper nano-ink, which is the same coating liquid as in Example 1-1, was applied such that the thickness of the first coating 1121 after drying was 2 µm. The average thickness of the first coating 1121 on the end face 11A in the longitudinal direction of the steel cable 11 was measured and confirmed to be 2 µm.

[0290] The rubber complex was prepared in the same manner as in Example 1-1, except for the points mentioned above.

[0291] In the rubber complex 10 obtained, the rubber 12 was arranged to cover the entire surface of the steel cable 11. A first coating 131, containing Cu and S, was applied to the end face 11A along the longitudinal side of the steel cable 11. A second coating 132 was applied to the side face 11B of the steel cable 11. The end face 11A and the side face 11B of the steel cable 11 were bonded to the rubber 12 by the first coating 131 and the second coating 132, respectively. The evaluation results are shown in Table 2. [Table 2] Evaluation results Example 2-1 C Example 2-2 A Example 2-3 A Example 2-4 B Example 2-5 C

[0292] The results shown in Table 2 confirmed that corrosion resistance tends to be improved by increasing the thickness of the first coating.

[0293] It is assumed that the covering can be formed with sufficient thickness by ensuring that the first coating has a certain thickness or more.

[0294] However, it was confirmed that corrosion resistance tended to decrease when the thickness of the first coating exceeded a certain threshold, as in experimental examples 2-4 and 2-5. This is thought to be due to the reaction layer with S (sulfur) in the rubber becoming porous. [Experimental Example 3]

[0295] Rubber complexes were manufactured according to the following process and their corrosion resistance was evaluated. Experimental examples 3-1 to 3-3 are embodiments. (Experimental Example 3-1)

[0296] When the first coating 1121 is formed on the end face 11A in the longitudinal direction of the steel cable 11, which is contained in the starting material of the rubber complex, using the application method, the conductive copper nano-ink, which is the same coating liquid as in Example 1-1, was applied such that the thickness of the first coating 1121 after drying was 0.15 µm.

[0297] When the coating liquid was applied to the end face 11A in the longitudinal direction of the steel cable 11, the end face 11A was partially masked in the longitudinal direction of the steel cable 11. This resulted in the area where the coating liquid was applied comprising 20% ​​of the end face. The average thickness of the first coating 1121 applied to the end face 11A in the longitudinal direction of the steel cable 11 was measured and confirmed to be 0.15 µm.

[0298] The rubber complex was prepared in the same manner as in Example 1-1, except for the points mentioned above.

[0299] In the rubber complex 10 obtained, the rubber 12 was arranged to cover the entire surface of the steel cable 11. A first coating 131, containing Cu and S, was applied to the end face 11A along the longitudinal side of the steel cable 11. A second coating 132 was applied to the side face 11B of the steel cable 11. The end face 11A and the side face 11B of the steel cable 11 were bonded to the rubber 12 by the first coating 131 and the second coating 132, respectively. The evaluation results are shown in Table 3. (Experimental Example 3-2)

[0300] When the first coating 1121 is formed on the end face 11A in the longitudinal direction of the steel cable 11, which is contained in the starting material of the rubber complex, using the application method, the conductive copper nano-ink, which is the same coating liquid as in Example 1-1, was applied such that the thickness of the first coating 1121 after drying was 0.15 µm.

[0301] When the coating liquid was applied to the end face 11A in the longitudinal direction of the steel cable 11, the end face 11A was partially masked in the longitudinal direction of the steel cable 11. This resulted in the area where the coating liquid was applied being 60% of the end face. The average thickness of the first coating 1121 applied to the end face 11A in the longitudinal direction of the steel cable 11 was measured and confirmed to be 0.15 µm.

[0302] The rubber complex was prepared in the same manner as in Example 1-1, except for the points mentioned above.

[0303] In the rubber complex 10 obtained, the rubber 12 was arranged to cover the entire surface of the steel cable 11. A first coating 131, containing Cu and S, was applied to the end face 11A along the longitudinal side of the steel cable 11. A second coating 132 was applied to the side face 11B of the steel cable 11. The end face 11A and the side face 11B of the steel cable 11 were bonded to the rubber 12 by the first coating 131 and the second coating 132, respectively. The evaluation results are shown in Table 3. (Experimental Example 3-3)

[0304] When the first coating 1121 is formed on the end face 11A in the longitudinal direction of the steel cable 11, which is contained in the starting material of the rubber complex, using the application method, the conductive copper nano-ink, which is the same coating liquid as in Example 1-1, was applied such that the thickness of the first coating 1121 after drying was 0.15 µm.

[0305] When the coating liquid was applied to the end face 11A in the longitudinal direction of the steel cable 11, the end face 11A was partially masked in the longitudinal direction of the steel cable 11. This resulted in the area where the coating liquid was applied being 80% of the end face. The average thickness of the first coating 1121 applied to the end face 11A in the longitudinal direction of the steel cable 11 was measured and confirmed to be 0.15 µm.

[0306] The rubber complex was prepared in the same manner as in Example 1-1, except for the points mentioned above.

[0307] In the rubber complex 10 obtained, the rubber 12 was arranged to cover the entire surface of the steel cable 11. A first coating 131, containing Cu and S, was applied to the end face 11A along the longitudinal side of the steel cable 11. A second coating 132 was applied to the side face 11B of the steel cable 11. The end face 11A and the side face 11B of the steel cable 11 were bonded to the rubber 12 by the first coating 131 and the second coating 132, respectively. The evaluation results are shown in Table 3. [Table 3] Evaluation results Example 3-1 C Example 3-2 B Example 3-3 A

[0308] According to the results shown in Table 3, it was confirmed that as the corrosion resistance test results improved, the area fraction of the coating fluid applied to the end face along the longitudinal direction of the steel cable increased. On the end face along the longitudinal direction of the steel cable, the proportion of the area where the coating formed and the area covered by the coating also increased, due to the increased area fraction of the coating fluid applied to the end face. As a result, it was concluded that the corrosion resistance was improved. [List of reference symbols] 10 Rubber complex 11 steel cables 11A Front 11B Side surface 111 Wire rod 112 Coating 1121 first coating 1122 second coating 12 rubber 121 Front rubber 13 Coverage 131 first covering 132 second covering X direction of the X-axis (latitude direction) Y direction of the Y-axis (longitudinal direction) Z direction of the Z-axis (thickness direction) 40 tires 41 Tread section 42 Side wall section 43 Bead section 44 Innerliner 45 Carcass (rubber complex) 46 Belt layer (rubber complex) 47 Bead wire

Claims

[1] Rubber complex (10) comprising a steel cable (11) and a rubber (12) covering at least part of a surface of the steel cable (11), wherein a first covering (131) containing Cu is arranged on an end face (11A) in a longitudinal direction of the steel cable (11). [2] Rubber complex (10) according to claim 1, wherein the first covering (131) further contains S. [3] Rubber complex (10) according to claim 1 or 2, wherein the first coating (131) further contains Zn. [4] Rubber complex (10) according to claim 3, wherein the first coating (131) further comprises one or more selected from Sn, Cr, Fe, Co and Ni. [5] Rubber complex (10) according to any one of claims 1 to 4, wherein the end face (11A) of the steel cable (11) is covered with the rubber (12) via the first covering (131). [6] Rubber complex (10) according to any one of claims 1 to 5, wherein the end face (11A) of the steel cable (11) is connected to the rubber (12) via the first covering (131). [7] Rubber complex (10) according to any one of claims 1 to 6, wherein the first covering (131) covers greater than or equal to 20% of the end face (11A). [8] Rubber complex (10) according to any one of claims 1 to 7, wherein a second covering (132), containing Cu, is arranged on a side surface (11B) of the steel cable (11). [9] Tire (40) comprising the rubber complex (10) according to any one of claims 1 to 8.

Images