Metal-resin joint

Abstract

To provide a metal-resin conjugate that achieve both high reliability for airtightness and low cost, as well as high joint strength.SOLUTION: In a metal-resin conjugate 1, a portion of a metal member 10 penetrates from a first side 21 to a second side 22 of a resin member 20. A junction between the two includes a hermetic joint 30 and a strong joint 40. The hermetic joint 30 comprises an electrodeposition coating film that bonds the metal member 10 and the resin member 20 together and prevents passage of gas between them. The strong joint 40 bonds the metal member 10 and the resin member 20 to each other with higher bonding strength than the hermetic joint 30. The hermetic joint 30 is formed over an entire circumferential direction of the metal member 10 in at least part of a region where the metal member 10 penetrates the resin member 20. The strong joint 40 includes a first strong joint 41 located on a first side 21 side of the hermetic joint 30 at least partially and a second strong joint 42 located on a second side 22 side of the hermetic joint 30 at least partially.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a metal-resin bonded body. [Background technology]

[0002] Metal materials are being replaced with resins in automobile parts, electrical and electronic products, and other industrial products, primarily to reduce costs by reducing weight and the number of parts.In recent years, in addition to simply replacing metal with resins, metal-resin joints that take advantage of the properties of metal materials and resin components according to the intended use have come into use.

[0003] In such a metal-resin bonded body, because dissimilar materials, i.e., metal and resin, are bonded together, there is a risk that sufficient adhesion between the two may not be achieved, resulting in a decrease in bond strength. Therefore, various methods for improving adhesion have been studied. For example, in the configuration disclosed in Patent Document 1, the bonding surface of the metal member with the resin member is roughened by etching with a chemical, and the metal member and the resin member are directly bonded at the bonding surface, thereby improving adhesion between the two. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Publication No. 2020-001271 Summary of the Invention [Problem to be solved by the invention]

[0005] However, in the configuration disclosed in Patent Document 1, the metal member and the resin member are directly bonded at the roughened bonding surface, leaving minute gaps between the metal member and the resin member. This makes it difficult to ensure airtightness between the metal member and the resin member. Another possible solution to ensure airtightness between the metal member and the resin member is to bond the metal member and the resin member with an adhesive that has high wettability to the roughened bonding surface, thereby increasing airtightness. However, applying the adhesive reliably and uniformly to the metal member that penetrates the resin member is difficult and expensive. Therefore, there is room for improvement in achieving both high reliability in airtightness and low cost.

[0006] The present invention has been made in view of the above background, and aims to provide a metal-resin joined body that achieves both high reliability in terms of airtightness and low cost, and also achieves high joining strength. [Means for solving the problem]

[0007] One aspect of the present invention is a metal-resin joined body formed by joining a metal member and a resin member through which a portion of the metal member penetrates from a first surface to a second surface, The joint between the metal member and the resin member includes an airtight joint portion that joins the metal member and the resin member to each other and is made of an electrodeposition coating film that prevents gas from passing between the metal member and the resin member, and a strong joint portion that joins the metal member and the resin member to each other with a joint strength higher than the joint strength at the airtight joint portion, the airtight joint is formed over the entire circumferential area of ​​the metal member in at least a part of a region where the metal member penetrates the resin member, The strong joint portion is in a metal-resin joint body and includes a first strong joint portion located closer to the first surface of the resin member than at least a portion of the airtight joint portion, and a second strong joint portion located closer to the second surface of the resin member than at least a portion of the airtight joint portion. [Effects of the Invention]

[0008] The metal-resin bonded body described above has an airtight joint between the metal member and the resin member, formed of an electrodeposition coating that prevents gas from passing through. This ensures sufficient airtightness between the metal member and the resin member. Furthermore, because the electrodeposition coating is easily formed reliably and uniformly, costs can be reduced compared to applying an adhesive. Furthermore, the bonded body includes a first strong joint portion located closer to the first surface of the resin member than at least a portion of the airtight joint, and a second strong joint portion located closer to the second surface of the resin member. This allows the first and second strong joint portions to maintain the bond between the metal member and the resin member even when force is applied to the end of the metal member that penetrates the resin member. The bonded state of the airtight joint between the first strong joint portion 41 and the second strong joint portion 42 is also maintained. These features allow for high reliability in airtightness, low cost, and high joint strength.

[0009] As described above, according to the present invention, it is possible to provide a metal-resin joined body that achieves both high reliability in terms of airtightness and low cost, and also achieves high joining strength. [Brief explanation of the drawings]

[0010] [Figure 1] 1A is a perspective view of a metal-resin bonded body in Example 1, and FIG. 1B is a top view of the metal-resin bonded body. [Figure 2] 2A is a cross-sectional view taken along line II-II in FIG. 1B, and FIG. 2B is a cross-sectional view taken along line IIb-IIb in FIG. 2A, in the first embodiment. [Figure 3] 2(a) is a partial enlarged view of a first strong bonding portion in FIG. 2(a), and FIG. 2(a) is a partial enlarged view of a second strong bonding portion in FIG. 2(a) in Example 1. [Figure 4] 3(a) to 3(c) are diagrams illustrating the steps of producing a metal-resin bonded body in Example 1. FIG. [Figure 5] 1 is a partially enlarged cross-sectional view of a metal member on which an electrodeposition coating film is formed in Example 1. FIG. [Figure 6]5(a) and 5(b) are other views for explaining the manufacturing process of a metal-resin bonded body in Example 1. FIG. [Figure 7] 7A is a cross-sectional view taken along line II-II in FIG. 1B, and FIG. 7B is an enlarged view of a portion of the first strong bonding portion in FIG. 7A, in Example 2. [Figure 8] 8A is a cross-sectional view taken along line II-II in FIG. 1B, FIG. 8B is a partially enlarged view of the first strong bonding portion in FIG. 8A, and FIG. 8C is a partially enlarged view of the second strong bonding portion in FIG. 8A, in Example 3. [Figure 9] 9(a) is a cross-sectional view taken along line II-II in FIG. 1(b), FIG. 9(b) is an enlarged view of a portion near the center of the first strong bonding portion in FIG. 9(a), and FIG. 9(c) is an enlarged view of a portion near the center of the second strong bonding portion in FIG. 9(a). [Figure 10] 10(a) is a top view of a metal-resin bonded body in Example 5, and FIG. 10(b) is a cross-sectional view taken along line IXb-IXb in FIG. 10(a). [Figure 11] 1(a) is a top view of a metal-resin bonded body in Example 6, and FIG. 1(b) is a cross-sectional view taken along line Xb-Xb in FIG. 1(a). [Figure 12] 12(a) and 12(b) are cross-sectional views of Example 7 taken along line II-II in FIG. 1(b), enlarged views of a portion of the first strong bonding portion in FIG. 12(a), and enlarged views of a portion of the second strong bonding portion in FIG. 12(a). [Figure 13] 13(a) is a cross-sectional view taken along line II-II in FIG. 1(b), FIG. 13(b) is a partially enlarged view of the first strong bonding portion in FIG. 13(a), and FIG. 13(c) is a partially enlarged view of the second strong bonding portion in FIG. 13(a). [Figure 14] 1(b) is a cross-sectional view taken along line II-II in FIG. 1(b), showing a metal-resin bonded body according to Example 9. FIG. [Figure 15] 13(a) and 13(b) are diagrams illustrating the manufacturing process of a metal-resin bonded body in Example 9. FIG. [Figure 16] FIG. 20 is a cross-sectional view taken along line II-II in FIG. 1(b) in Example 10. DETAILED DESCRIPTION OF THE INVENTION

[0011] the resin member has a plate shape, and a pair of main surfaces of the resin member constitute the first surface and the second surface; Preferably, the metal member has a thickness-direction extending region that extends in the thickness direction of the resin member in a region that penetrates the resin member and is joined to the resin member via the airtight joint, and a first joining region that extends from the thickness-direction extending region toward the first surface, bends parallel to the first surface, and is joined to the first surface via the first strong joint region. In this case, when a tensile force is applied to the metal member toward the second surface of the resin member, the first joining region of the metal member functions as an anchor for the resin member, thereby increasing the joining strength at the first strong joint.

[0012] the resin member has a plate shape, and a pair of main surfaces of the resin member constitute the first surface and the second surface; Preferably, the metal member has a thickness-direction extending region that extends in the thickness direction of the resin member in a region that penetrates the resin member and is joined to the resin member via the airtight joint, and a first joining region that extends from the thickness-direction extending region toward the first surface, bends parallel to the first surface, is covered by the resin member, and is joined to the resin member via the first strong joint. In this case, the first joining region of the metal member is embedded in the resin member and functions as an anchor, thereby increasing the joining strength at the first strong joint.

[0013] Preferably, the metal member further has a second bonding region that extends from the thickness-direction extending region toward the second surface, bends parallel to the second surface, and is bonded to the second surface of the resin member via the second strong bonding portion. In this case, when a tensile force is applied to the metal member toward the first surface of the resin member, the second bonding region of the metal member functions as an anchor for the resin member, thereby increasing the bonding strength at the second strong bonding portion.

[0014] Preferably, the metal member further has a second bonding region that extends from the thickness-direction extending portion toward the second surface, bends parallel to the second surface, is covered with the resin member, and is bonded to the resin member via the second strong bonding portion. In this case, the second bonding region of the metal member is embedded in the resin member and functions as an anchor, thereby increasing the bonding strength of the second strong bonding portion.

[0015] It is preferable that the first and second bonding regions of the metal member sandwich a portion of the resin member in the thickness direction. In this case, the anchoring effect of the first and second strong bonding regions to the resin member is further improved, thereby further increasing the bonding strength of the first and second strong bonding regions. Furthermore, the cross-sectional shape of the metal member in the first bonding region, the second bonding region, and the thickness-direction extending region is a substantially U-shaped shape with the thickness-direction extending region as the bottom. Therefore, when forming an electrodeposition coating film on the thickness-direction extending region, it is easy to immerse only the thickness-direction extending region in an electrodeposition coating bath. This makes it easy to form an electrodeposition coating film in the region where an airtight joint is desired, improving workability.

[0016] At least one of the first strong joint portion and the second strong joint portion is preferably formed by closely adhering the resin member along an uneven shape formed by roughening the surface of the metal member. In this case, the resin member is closely adhering along the uneven shape, which further improves the anchor effect on the resin member, thereby further increasing the bonding strength of the first strong joint portion or the second strong joint portion.

[0017] At least one of the first strong bond portion and the second strong bond portion is preferably formed by closely adhering the resin member along a concave-convex shape or through holes formed by pressing or machining the metal member. In this case, the anchor effect on the resin member is further improved by closely adhering along the concave-convex shape or through holes, thereby further increasing the bonding strength of the first strong bond portion or the second strong bond portion.

[0018] The resin member is preferably formed by insert molding using the metal member provided with the electrodeposition coating film as an insert part. In this case, the metal member provided with the electrodeposition coating film as an insert part is set in a mold, and a resin material is filled around it, thereby enabling a three-dimensional molded product in which the metal member and the resin member are integrated with high precision.

[0019] The resin member is made of engineering plastic or super engineering plastic, The electrodeposition coating is preferably made of epoxy resin, polyamide-imide resin, or polyimide resin. In this case, the resin member is an engineering plastic or super engineering plastic, which can improve insulation, heat resistance, chemical resistance, and mechanical properties. Furthermore, electrodeposition coatings made of epoxy resin, polyamide-imide resin, or polyimide resin have good wettability and compatibility with thermally fused engineering plastics or super engineering plastics, and have surface properties that are highly compatible with engineering plastics and super engineering plastics. Furthermore, because these materials have excellent heat resistance, they are less susceptible to thermal degradation caused by thermally fused engineering plastics or super engineering plastics during molding. Therefore, by using the materials for forming the resin member and the electrodeposition coating as described above, sufficient adhesion can be achieved between the resin member and the metal member. Furthermore, because the resin member and the adhesive layer are both resins, sufficient adhesion can be achieved between them. As a result, the airtightness between the resin member and the metal member can be further improved.

[0020] In this specification, engineering plastics refer to resin members with a heat resistance temperature of 100°C or higher and superior tensile strength and elastic modulus to so-called general-purpose plastics, while super engineering plastics refer to resin members with a heat resistance temperature of 150°C or higher among engineering plastics. [Example]

[0021] Example 1 Examples of the metal-resin bonded body will be described below with reference to FIGS. As shown in Fig. 1(a), the metal-resin bonded body 1 of this Example 1 includes a metal member 10 and a resin member 20. As shown in Fig. 2(a), a part of the metal member 10 penetrates from a first surface 21 to a second surface 22 of the resin member 20. The joint between the metal member 10 and the resin member 20 includes an airtight joint 30 and a strong joint 40. The airtight joint 30 is made of an electrodeposition coating that joins the metal member 10 and the resin member 20 together and prevents gas from passing between the metal member 10 and the resin member 20. The strong joint portion 40 joins the metal member 10 and the resin member 20 together with a joint strength higher than the joint strength of the airtight joint portion 30 . Furthermore, the airtight joint 30 is formed over the entire circumferential area of ​​the metal member 10 in at least a part of the region where the metal member 10 penetrates the resin member 20, as shown in FIG. 2(b). As shown in Figure 2(a), the strong bonding portion 40 includes a first strong bonding portion 41 located closer to the first surface 21 of the resin member 20 than at least a portion of the airtight bonding portion 30, and a second strong bonding portion 42 located closer to the second surface 22 of the resin member 20 than at least a portion of the airtight bonding portion 30.

[0022] The metal-resin bonded body 1 of Example 1 will be described in detail below. 1(a) and 1(b), in the metal-resin bonded body 1 of Example 1, the metal member 10 penetrates the resin member 20. In Example 1, the horizontal direction, which is one of the main surface directions of the resin member 20, is designated as X, the vertical direction, which is one of the main surface directions of the resin member 20 and is perpendicular to the horizontal direction X, is designated as Y, and the height direction, which is the thickness direction of the resin member 20 and is perpendicular to the horizontal direction X and the vertical direction Y, is designated as Z.

[0023] The metal member 10 may be made of copper, an aluminum alloy, or the like, and is made of copper in this Example 1. In this Example 1, the metal member 10 is formed by bending a plate material, but is not limited to this. The metal member 10 may be formed by bending a round bar material or a square bar material, or by pressing or machining. As shown in FIG. 2( a), the metal member 10 has a region 10a penetrating the resin member 20, a region 10b protruding outward from a first surface 21 of the resin member 20, and a region 10c protruding outward from a second surface 22 of the resin member 20. In this Example 1, a hermetic joint 30 (described later) is formed in a thickness-direction extending region 13, which is a portion of the region 10a penetrating the resin member 20 and extends in the thickness direction Z of the resin member 20.

[0024] As shown in FIG. 2(a), the metal member 10 has a first bonding region 11 and a second bonding region 12. The first bonding region 11 extends from the thickness-direction extending region 13 toward the first surface 21 in a region 10b of the metal member 10 that protrudes outward from the first surface 21 of the resin member 20, and is bent parallel to the first surface 21 to form a state along the first surface 21. In this Example 1, as shown in FIG. 3(a), the surface of the first bonding region 11 of the metal member 10 facing the resin member 20 is roughened to form a fine uneven shape. The roughening method is not limited, and laser processing, etching, roughening plating, etc. can be used. The roughness of the surface of the roughened first bonding region 11 is not limited. The surface of the metal member 10 opposite the resin member 20 side of the first bonding region 11 is exposed from the resin member 20 and can be connected to, for example, a terminal or the like to enable electrical connection.

[0025] On the other hand, as shown in Fig. 2(a), the second bonding region 12 of the metal member 10 extends from the thickness-direction extending region 13 toward the second surface 22 in a region 10a penetrating the resin member 20, bends in the X direction parallel to the second surface 22, and is covered by the resin member 20. Note that the region of the resin member 20 that covers the second bonding region 12 is raised by the thickness of the metal member 10 and is thicker than the other regions. In this Example 1, as shown in Fig. 3(b), the surface of the second bonding region 12 of the metal member 10 is subjected to a roughening treatment similar to that of the surface of the first bonding region 11, thereby forming a fine uneven shape.

[0026] In this Example 1, as described above, the first bonding region 11 and the second bonding region 12 in the metal member 10 are bent toward the same side from the thickness-direction extending region 13 as shown in Fig. 2(a), and the cross-sectional shape of the metal member 10 in the first bonding region 11, the second bonding region 12, and the thickness-direction extending region 13 is a substantially U-shape with the thickness-direction extending region 13 as the bottom. As a result, a part of the resin member 20 is sandwiched between the first bonding region 11 and the second bonding region 12 in the thickness direction Z.

[0027] 2(a), of the ends of the metal member 10, an end 14 on the first surface 21 side of the resin member 20 is bent inward of the resin member 20 and is located inside the resin member 20. Furthermore, of the ends of the metal member 10, an end 15 on the second surface 22 side of the resin member 20 extends downward in the thickness direction Z. The end 15 of the metal member 10 can be connected to, for example, a terminal or the like to allow electricity to pass through.

[0028] Next, the shape of the resin member 20 in Example 1 is not limited. In Example 1, the resin member 20 is plate-shaped as shown in FIGS. 1(a) and 2(a), but the outer shape of the resin member 20 is not specified. The resin material constituting the resin member 20 is preferably a thermoplastic resin material to allow for insert molding, as described below. Considering exposure to high temperatures during insert molding, the resin material preferably has a heat resistance temperature of 150°C or higher. Furthermore, to ensure compatibility and adhesion between the resin material of the resin member 20 and the material forming the airtight joint 30, as described below, it is preferable that the solubility parameters (SP values) of the two materials are similar. For example, in consideration of the use of an epoxy resin with an SP value of approximately 11 or a polyamide-imide resin or polyimide resin with an SP value of approximately 13.6 as the material forming the airtight joint 30, a resin material for the resin member 20 with a solubility parameter (SP value) in the range of 9.5 to 15 can be used.

[0029] For example, the resin material constituting the resin member 20 may be engineering plastics such as nylon resin or polycarbonate resin, or super engineering plastics such as polyphenylene sulfide (PPS) resin, polysulfone (PSF) resin, polyethersulfone (PES) resin, or polyamide-imide (PAI) resin, and in this example, PPS resin is used.

[0030] As shown in FIG. 2(a), the joint between the metal member 10 and the resin member 20 includes an airtight joint 30 and a strong joint 40. As shown in FIG. 2(b), the airtight joint 30 is formed over the entire circumferential area of ​​the thickness-direction extending region 13. The airtight joint 30 is made of an electrodeposition coating film 30a. The material used for the airtight joint 30 has higher adhesion to the metal member 10 than the resin material constituting the resin member 20. For example, the material for the airtight joint 30 may be a thermosetting epoxy resin, polyamide-imide resin, or polyimide resin, which is a cationic electrodeposition paint. In this example, a thermosetting epoxy resin is used. Although not shown, a compatibility layer is formed between the resin member 20 and the airtight joint 30, resulting from the compatibility of the two resin members. The boundary between the compatibility layer and the resin member 20 is unclear. The compatibility layer allows the airtight joint 30 to prevent gas from passing between the resin member 20 and the metal member 10 .

[0031] As shown in FIG. 2( a), the strong bond 40 between the metal member 10 and the resin member 20 includes a first strong bond 41 and a second strong bond 42. As shown in FIG. 3( a), the first strong bond 41 is formed by the resin member 20 closely adhering to the uneven shape of the first bonding region 11 of the roughened metal member 10. Similarly, as shown in FIG. 3( b), the second strong bond 42 is formed by the resin member 20 closely adhering to the uneven shape of the second bonding region 12 of the roughened metal member 10. Because the first strong bond 41 and the second strong bond 42 are formed by the resin member 20 closely adhering to the roughened first bonding region 11 and second bonding region 12, the bond strength between the metal member 10 and the resin member 20 at the first bonding region 11 and second bonding region 12 is higher than the bond strength at the airtight bond 30.

[0032] A method for producing the metal-resin bonded body 1 of this example will be described below. First, as shown in Fig. 4(a), a metal member forming step S1 is performed to form the metal member 10 into a predetermined shape. In this Example 1, in the metal member forming step S1, a long metal plate is bent to form the shape shown in Fig. 4(a).

[0033] Next, a coating formation step S2 is performed to form an electrodeposition coating film 30a shown in FIG. 4(c) on the metal member 10. In Example 1, the coating formation step S2 is performed as follows. First, the surface of the metal member 10 is cleaned and degreased. Then, as shown in FIG. 4(b), the thickness-direction extending region 13 of the metal member 10 after the cleaning and degreasing is immersed in an electrodeposition coating bath 101 filled with a cationic epoxy resin-based electrodeposition paint 102 having a solids concentration of 20%, and a voltage of 200 V is applied for 3 minutes. In Example 1, the cationic epoxy resin-based electrodeposition paint 102 used was Insuleed 3030, manufactured by Nippon Paint Co., Ltd. Then, the metal member 10 is removed from the bath, washed with water, and dried in a drying oven at 130°C for 20 minutes. As a result, as shown in FIGS. 4(c) and 5, an electrodeposition coating film 30a made of a semi-cured epoxy resin coating was formed over the entire circumferential area of ​​the thickness-direction extending region 13.

[0034] The average thickness (T) of the electrodeposition coating 30a shown in Figure 5 can be in the range of 10 to 80 µm, preferably in the range of 20 to 50 µm, and in this example, the average thickness is 50 µm. An average thickness of the electrodeposition coating 30a less than 10 µm is undesirable because it can cause uneven coating or areas that are not coated. Furthermore, an average thickness of the electrodeposition coating 30a greater than 80 µm is likely to take an excessively long time to form the coating, which is not practical.

[0035] Then, the insert molding step S3 shown in FIGS. 6(a) and 6(b) is performed. In the insert molding step S3, first, a mold divided into two parts, an upper mold 51 and a lower mold 52 shown in FIG. 6(a), is prepared. The upper mold 51 has a recess 51a that conforms to the outer shape of the upper portion of the metal member 10 and the first surface 21 side of the resin member 20, and the lower mold 52 has a recess 52a that conforms to the outer shape of the lower portion of the metal member 10 and the second surface 22 side of the resin member 20. Then, as shown in FIG. 6(a), the metal member 10 provided with an electrodeposition coating film 30a made of a semi-cured epoxy resin coating is set between the upper mold 51 and the lower mold 52. Thereafter, PPS resin heated to 330°C and melted is poured between the upper mold 51 and the lower mold 52 to form the resin member 20 as shown in FIG. 6(b). As a result, an airtight joint 30 consisting of an electrodeposition coating film 30a is formed between the metal member 10 and the resin member 20, and the metal member 10 and the resin member 20 are joined to each other via the airtight joint 30, thereby forming a metal-resin joined body 1 shown in Figure 2(a).

[0036] Next, the effects of the metal-resin bonded body 1 of the present Example 1 will be described in detail. In the metal-resin joined body 1 of Example 1, the joint between the metal member 10 and the resin member 20 has an airtight joint 30 made of an electrodeposition coating film 30a that prevents gas from passing through, thereby ensuring sufficient airtightness between the metal member 10 and the resin member 20. Furthermore, the electrodeposition coating film 30a is easily formed reliably and uniformly, thereby reducing costs compared to applying an adhesive. Furthermore, as a strong joint 40 having a higher joint strength than the airtight joint 30, a first strong joint 41 is provided, which is located closer to the first surface 21 of the resin member 20 than at least a portion of the airtight joint 30, and a second strong joint 42 is provided, which is located closer to the second surface 22 of the resin member 20. As a result, even if force is applied to the ends 14, 15 of the metal member 10 that penetrate the resin member 20, the first strong joint portion 41 and the second strong joint portion 42 can maintain the bonded state between the metal member 10 and the resin member 20, and the bonded state of the airtight joint portion 30 between the first strong joint portion 41 and the second strong joint portion 42 can also be maintained. As a result, it is possible to achieve both high reliability in airtightness and low cost, and to achieve high joint strength.

[0037] The metal-resin bonded body 1 of Example 1 can be used, for example, as a lid for a storage container. This prevents the metal member 10 from reducing the airtightness of the storage container, making it possible to provide a storage container with excellent airtightness. The storage container can be used as a case for an electrical component such as a secondary battery or a capacitor, and the metal member 10 can be used as part of an electrode terminal in the secondary battery or capacitor.

[0038] In this Example 1, the resin member 20 is plate-shaped, and a pair of main surfaces of the resin member 20 constitute a first surface 21 and a second surface 22. The metal member 10 has a thickness-direction extending region 13 that extends in the thickness direction Z of the resin member 20 in a region 10a that penetrates the resin member 20 and is joined to the resin member 20 via an airtight joint 30, and a first bonding region 11 that extends from the thickness-direction extending region 13 toward the first surface 21, bends parallel to the first surface 21, and is joined to the first surface 21 via a first strong bonding region 41. As a result, when a tensile force is applied to the metal member 10 toward the second surface 22 of the resin member 20 (i.e., downward in the Z direction), the first bonding region 11 of the metal member 10 functions as an anchor for the resin member 20, thereby increasing the bonding strength at the first strong bonding region 41. Furthermore, in this Example 1, of the ends of the metal member 10, the end 14 on the first surface 21 side of the resin member 20 is bent and positioned inside the resin member 20. This can further increase the bonding strength of the first strong bonding portion 41.

[0039] Furthermore, in this Example 1, the metal member 10 further has a second bonding region 12 that extends from the thickness direction extending region 13 toward the second surface 22, is bent parallel to the second surface 22, is covered with the resin member 20, and is bonded to the resin member 20 via the second strong bonding portion 42. As a result, the second bonding region 12 of the metal member 10 is embedded in the resin member 20 and functions as an anchor, thereby increasing the bonding strength at the second strong bonding portion 42.

[0040] In Example 1, the first and second bonding regions 11 and 12 of the metal member 10 sandwich a portion of the resin member 20 in the thickness direction Z. This further improves the anchoring effect of the first and second strong bonding regions 41 and 42 on the resin member 20, thereby further increasing the bonding strength of the first and second strong bonding regions 41 and 42. Furthermore, the cross-sectional shape of the metal member 10 in the first and second bonding regions 11, 12, and thickness-direction-extending region 13 is generally U-shaped with the thickness-direction-extending region 13 at its bottom. This makes it easy to immerse only the thickness-direction-extending region 13 in the bath 101 for electrodeposition coating when forming the electrodeposition coating film 30a on the thickness-direction-extending region 13. This facilitates forming the electrodeposition coating film 30a in the region where the airtight bonding portion 30 is to be formed, improving workability.

[0041] In this Example 1, the first strong bonding portion 41 and the second strong bonding portion 42 are formed by closely adhering the resin member 20 along the uneven shape formed by roughening the surface of the metal member 10. This further improves the anchor effect on the resin member 20 by adhering the resin member 20 along the uneven shape, and the bonding strength of the first strong bonding portion 41 and the second strong bonding portion 42 can be further increased.

[0042] In this Example 1, the resin member 20 is formed by insert molding using the metal member 10 provided with the electrodeposition coating film 30a as an insert part. As a result, by setting the metal member 10 provided with the electrodeposition coating film 30a as an insert part in a mold and filling the area around it with resin material, it is possible to mold a three-dimensional molded product in which the metal member 10 and the resin member 20 are integrated with high precision.

[0043] In Example 1, the resin member 20 is made of an engineering plastic or super engineering plastic. The electrodeposition coating 30a is made of an epoxy resin, a polyamide-imide resin, or a polyimide resin. This allows the resin member 20, which is made of an engineering plastic or super engineering plastic, to have improved insulation, heat resistance, chemical resistance, and mechanical properties. The electrodeposition coating 30a, made of an epoxy resin, a polyamide-imide resin, or a polyimide resin, has good wettability and compatibility with thermally melted engineering plastics or super engineering plastics, providing surface properties with high affinity and compatibility with the engineering plastics or super engineering plastics. Furthermore, because these materials have excellent heat resistance, they are less susceptible to thermal degradation caused by thermally melted engineering plastics or super engineering plastics during molding. Therefore, by using the materials for forming the resin member 20 and the electrodeposition coating 30a as described above, sufficient adhesion can be achieved between the metal member 10 and the resin member 20. Furthermore, because the resin member 20 and the electrodeposition coating 30a are both resins, sufficient adhesion can be achieved at the airtight joint 30 formed by the electrodeposition coating 30a. As a result, it is possible to further improve the airtightness between the metal member 10 and the resin member 20. Furthermore, because the electrodeposition coating provides good adhesion of the material forming the electrodeposition coating film 30a, it is possible to prevent uncoated areas in the desired area where the airtight joint 30 is to be formed, and it is possible to form a uniform resin coating because the material is less likely to drip. As a result, it is easier to manage the formation of the airtight joint 30.

[0044] As described above, according to the first embodiment, it is possible to provide a metal-resin joined body 1 that achieves both high reliability in airtightness and low cost, and also achieves high joining strength.

[0045] Example 2 In the above-described Example 1, the first bonding region 11 of the metal member 10 was exposed from the first surface 21 of the resin member 20 and bonded to the first surface 21, as shown in FIG. 2(a). Instead, in Example 2, as shown in FIG. 7(a), the first bonding region 11 of the metal member 10 extends from the thickness direction extending region 13 toward the first surface 21, bends parallel to the first surface 21, is covered by the resin member 20, and is bonded to the resin member 20 via a first strong bonding portion 41. As shown in FIG. 7(b), an uneven shape is formed on the surface of the first bonding region 11 by a surface roughening treatment, and the resin member 20 adheres to the uneven shape, thereby forming the first strong bonding portion 41. As shown in FIG. 7(a), the end 14 of the metal member 10 bends upward in the thickness direction Z from the first bonding region 11 and protrudes from the first surface 21 of the resin member 20. The end 14 of the metal member 10 can be connected to, for example, a terminal or the like to allow electricity to pass through. Regarding other configurations in the second embodiment, the same components as those in the first embodiment are denoted by the same reference numerals, and the description thereof will be omitted.

[0046] According to the metal-resin bonded body 1 of Example 2, the first bonding region 11 of the metal member 10 is embedded in the resin member 20 and functions as an anchor, thereby increasing the bonding strength of the first strong bond portion 41. Note that Example 2 also achieves the same effects as Example 1.

[0047] Example 3 In the above-described Example 1, the second bonding region 12 of the metal member 10 was embedded in the resin member 20 as shown in Fig. 2(a), but instead, in this Example 3, as shown in Fig. 8(a), the second bonding region 12 of the metal member 10 extends from the thickness direction extending region 13 toward the second surface 22 and is bent parallel to the second surface 22 to be bonded to the second surface 22 of the resin member 20 via a second strong bonding portion 42. Furthermore, while the end portion 14 of the metal member 10 in the above-described Example 1 was embedded in the resin member 20, in this Example 3, it is exposed on the first surface 21 of the metal member 10.

[0048] In this Example 3, as shown in FIG. 8(b), similar to Example 1 described above, the resin member 20 adheres to the first bonding region 11 of the metal member 10 along the roughened, uneven surface on the resin member 20 side, thereby forming a first strong bond 41. Similarly, as shown in FIG. 8(c), the resin member 20 adheres to the second bonding region 12 of the metal member 10 along the roughened, uneven surface on the resin member 20 side, thereby forming a second strong bond 42. In Example 3, as shown in FIG. 8(a), the airtight bond 30 is formed in the entire circumferential direction over the entire thickness-direction extending region 13. However, the present invention is not limited to this, and the airtight bond 30 may be formed in the entire circumferential direction over a portion of the thickness-direction extending region 13. Regarding other configurations in Example 3, configurations equivalent to those in Example 1 are designated by the same reference numerals, and descriptions thereof will be omitted.

[0049] In this Example 3, as described above, the second bonding region 12 of the metal member 10 is bent parallel to the second surface 22 and bonded to the second surface 22 of the resin member 20 via the second strong bonding portion 42. As a result, when a tensile force is applied to the metal member 10 toward the first surface 21 of the resin member 20 (i.e., upward in the Z direction), the second bonding region 12 of the metal member 10 functions as an anchor for the resin member 20, thereby increasing the bonding strength at the second strong bonding portion 42. Note that Example 3 also achieves the same effects as Example 1.

[0050] Example 4 In this Example 4, as shown in Figure 9(a), instead of the above-mentioned Example 3, the airtight joint 30 (electrodeposition coating film 30a) is formed in the metal member 10 together with the thickness-direction extending region 13, from the thickness-direction extending region 13 to near the center in the X direction of the first joint region 11 and near the center in the X direction of the second joint region 12.

[0051] Because the electrodeposition coating 30a is formed uniformly as a thin film, the surface of the electrodeposition coating 30a formed in the first bonding region 11 has an uneven shape formed by roughening the first bonding region 11, as shown in FIG. 9(b). In the portion of the first bonding region 11 where the electrodeposition coating 30a is provided, a part of the resin member 20 penetrates into the uneven shape that appears on the surface of the electrodeposition coating 30a, forming a first strong bond 41, and the electrodeposition coating 30a and a part of the resin member 20 are bonded to form the airtight bond 30. Even in this configuration, the airtight bond 30 is always formed in the thickness-direction extending region 13 of the metal member 10 that penetrates the resin member 20. Therefore, it can be said that the first strong bond 41 is located closer to the first surface 21 than the part of the airtight bond 30 that is formed in the thickness-direction extending region 13.

[0052] 9(c), the surface of the electrodeposition coating 30a formed in the second bonding region 12 also has an uneven shape formed by roughening in the second bonding region 12. In the portion of the second bonding region 12 where the electrodeposition coating 30a is provided, a part of the resin member 20 fits into the uneven shape that appears on the surface of the electrodeposition coating 30a, forming a second strong bonding portion 42, and the electrodeposition coating 30a and a part of the resin member 20 are bonded to form the airtight bonding portion 30. In this configuration as well, the second strong bonding portion 42 can be said to be located closer to the second surface 22 than the portion of the airtight bonding portion 30 formed in the thickness-direction extending region 13.

[0053] Regarding other configurations in the present embodiment 4, the same components as those in the embodiment 3 are denoted by the same reference numerals, and the description thereof will be omitted. The present embodiment 4 also achieves the same effects as those in the embodiment 3 described above.

[0054] Example 5 10(a) and 10(b), in this Example 5, the metal member 10 is provided such that the thickness-direction extending region 13 is located within a through hole 61 provided in a metal plate 60, and the resin member 20 is provided so as to seal a gap between the through hole 61 of the metal plate 60 and the thickness-direction extending region 13 of the metal member 10. An adhesive layer 62 made of an electrodeposition coating is formed on the inner circumferential surface of the through hole 61 of the metal plate 60 and on the surface of the metal plate 60 around the through hole 61 at the joint between the metal plate 60 and the resin member 20, and the metal plate 60 and the resin member 20 are joined together via the adhesive layer 62 in an airtight manner. Furthermore, the resin member 20 is in close contact with surfaces 63 and 64 of the metal plate 60 at the joint between the metal plate 60 and the resin member 20, except for the adhesive layer 62, along the uneven shape formed by surface roughening. As a result, the metal plate 60 and the resin member 20 are bonded to each other at surfaces 63, 64 of the metal plate 60 with a bonding strength higher than that of the adhesive layer 62. The electrodeposition coating that forms the adhesive layer 62 can have the same configuration as the above-mentioned electrodeposition coating coating 30a and can be formed by the same method. With regard to other configurations in Example 5, configurations that are equivalent to those in Example 3 are assigned the same reference numerals, and descriptions thereof will be omitted.

[0055] In this Example 5, similarly to the above-described Example 3, the metal member 10 and the resin member 20 are joined to each other so as to exhibit high airtightness and high joint strength, and similarly, the metal plate 60 and the resin member 20 are joined to each other so as to exhibit high airtightness and high joint strength. The metal-resin joined body 1 of this Example 5 can be used, for example, as a lid for a metal storage container. Note that this Example 5 also achieves the same effects as Example 3.

[0056] In this Example 5, the surface of the thickness-direction extending region 13 is not roughened, but instead, the surface of the thickness-direction extending region 13 may be roughened continuously from the roughening treatment in the first bonding region 11 and the second bonding region 12. In this case, the same effect as in Example 5 is also achieved.

[0057] Example 6 In Example 3 described above, as shown in FIGS. 8(b) and 8(c), the first strong bond 41 and the second strong bond 42 of the metal member 10 were formed by adhering the resin member 20 to the uneven surface formed by roughening the first bonding region 11 and the second bonding region 12. Alternatively, in Example 6, as shown in FIGS. 11(a) and 11(b), the first strong bond 41 was formed by adhering the resin member 20 along two through holes 11a formed in the first bonding region 11 by pressing or machining, such that a portion of the resin member 20 penetrates the through holes 11a from the underside of the first bonding region 11 and wraps around to the upper surface of the first bonding region 11 on the opposite side. This allows the first strong bond 41 to function as an anchor, achieving high bonding strength. Note that the two first strong bond portions 41 are spaced a predetermined distance from each other on the upper surface of the first bonding region 11, and a terminal or the like can be connected to the area between them to allow electrical connection.

[0058] 11(a) and 11(b), the second strong bond 42 is also formed by adhering the resin member 20 along two through holes 12a formed in the second bonding region 12 by press working or machining, so that a portion of the resin member 20 penetrates the through holes 12a from the upper surface of the second bonding region 12 and wraps around to the lower surface of the second bonding region 12 on the opposite side. This allows the second strong bond 42 to function as an anchor, resulting in high bonding strength. Regarding other configurations in this Example 6, configurations equivalent to those in Examples 1 to 4 are designated by the same reference numerals, and their description will be omitted. This Example 6 also achieves the same effects as Example 1.

[0059] Example 7 In Example 6 described above, as shown in FIGS. 11(a) and 11(b), the first strong bond 41 and the second strong bond 42 were formed by inserting a portion of the resin member 20 into the through holes 11a, 12a formed in the first bonding region 11 and the second bonding region 12 and wrapping around to the opposite side. Instead, in Example 7, as shown in FIG. 12(a), the first strong bond 41 and the second strong bond 42 were formed by inserting a portion of the resin member 20 into the groove-shaped uneven shapes 11b, 12b formed in the first bonding region 11 and the second bonding region 12. As shown in FIG. 12(b), the uneven shape 11b formed in the first bonding region 11 has a cross-sectional shape that is approximately a T-shaped groove. Furthermore, as shown in FIG. 12(c), the uneven shape 12b formed in the second bonding region 12 has a cross-sectional shape that is approximately a T-shaped groove with the shape upside down. The uneven shapes 11b, 12b can be formed by laser processing, press processing, or machining. The uneven shapes 11b and 12b may have any shape as long as the part of the resin member 20 that has entered the uneven shapes 11b and 12b functions as an anchor, and instead of the above shape, for example, a dovetail shape having a trapezoidal cross section may be used. Regarding other configurations in this Example 7, the same reference numerals are used for configurations that are the same as those in Examples 1 to 5, and the description thereof will be omitted.

[0060] In this Example 7, at the first strong joint portion 41 and the second strong joint portion 42, a part of the resin member 20 that has entered the uneven shapes 11b, 12b functions as an anchor, thereby obtaining high joint strength. With regard to other configurations in Example 7, configurations that are equivalent to those in Examples 1 to 5 are given the same reference numerals, and descriptions thereof will be omitted. Also, this Example 7 achieves the same effects as those in Example 1.

[0061] Example 8 In this Example 8, as shown in Figure 13(a), instead of the case of the above-mentioned Example 7, the airtight joint 30 (electrodeposition coating film 30a) is formed in the metal member 10 not only in the thickness direction extending region 13 but also in a region including the two of the four uneven shapes 11b that are closer to the thickness direction extending region 13, and the two of the four uneven shapes 12b that are closer to the thickness direction extending region 13.

[0062] 13(b), of the four concave-convex shapes 11b formed in the first joint region 11, the two concave-convex shapes 11b closer to the thickness-direction extending region 13 also have an electrodeposition coating film 30a formed on the inner surface of the concave-convex shapes 11b. A portion of the resin member 20 enters the concave-convex shapes 11b to form a first strong joint 41, and the electrodeposition coating film 30a in the concave-convex shapes 11b and the portion of the resin member 20 that has entered the concave-convex shapes 11b are joined to form an airtight joint 30. Even in this configuration, the airtight joint 30 is always formed in the thickness-direction extending region 13 of the metal member 10 that penetrates the resin member 20. Therefore, the first strong joint 41 can be said to be located closer to the first surface 21 than the portion of the airtight joint 30 formed in the thickness-direction extending region 13.

[0063] 13(c), of the four concave-convex shapes 12b formed in the second joint region 12, two concave-convex shapes 12b closer to the thickness-direction extending region 13 also have an electrodeposition coating 30a formed on the inner surface of the concave-convex shapes 12b. A portion of the resin member 20 enters the concave-convex shapes 12b to form a second strong joint 42, and the electrodeposition coating 30a in the concave-convex shapes 12b and the portion of the resin member 20 that has entered the concave-convex shapes 12b are joined to form the airtight joint 30. In this configuration, the second strong joint 42 can also be said to be located closer to the second surface 22 than the portion of the airtight joint 30 formed in the thickness-direction extending region 13.

[0064] Regarding other configurations in the present embodiment 8, the same components as those in the embodiment 7 are denoted by the same reference numerals, and the description thereof will be omitted. The present embodiment 8 also achieves the same effects as those in the above-described embodiment 7.

[0065] Example 9 In Example 6 described above, as shown in FIGS. 11(a) and 11(b), the second bonding region 12 of the metal member 10 extended from the thickness direction extending region 13 toward the second surface 22 and was bent parallel to the second surface 22 to be bonded to the second surface 22 of the resin member 20 via the second strong bonding portion 42. Alternatively, in Example 9, as shown in FIGS. 14(a) and 14(b), the second bonding region 12 of the metal member 10 extended downward in the Z direction from the thickness direction extending region 13, and two through holes 12a formed by machining were covered with the resin member 20, thereby causing portions of the resin member 20 to enter the through holes 12a, thereby forming the second strong bonding portion 42. The resin member 20 is then tightly attached to the second bonding region 12 of the metal member 10 by the second strong bonding portion 42.

[0066] 14(b), in this Example 9, a built-up portion 22a is provided on the second surface 22 of the resin member 20, and the built-up portion 22a forms the second strong bonding portion 42. This increases the size of the bonding portion between the metal member 10 and the resin member 20 by the thickness of the built-up portion 22a, thereby improving the bonding strength at the second strong bonding portion 42.

[0067] In Example 9, as shown in Fig. 15(a), the thickness-direction extending region 13 is immersed in an electrodeposition coating bath 101, and an electrodeposition coating film 30a can be formed on the thickness-direction extending region 13 as shown in Fig. 15(b) in the same manner as in Example 1. Other components in Example 9 that are equivalent to those in Example 6 are designated by the same reference numerals, and their description will be omitted. Thus, Example 9 can also achieve the same effects as Example 6.

[0068] Example 10 In the above-described Example 9, as shown in FIG. 14(b), the through hole 12a formed by machining was covered with the resin member 20, and a portion of the resin member 20 was allowed to fill the through hole 12a, thereby forming the second strong bond 42. Instead, in the present Example 10, as shown in FIG. 16, a recess 12c was formed by machining in the second bonding region 12 of the metal member 10, and a protrusion 12d was formed on the opposite side of the recess 12c in the second bonding region 12. The resin member 20 of the buildup portion 22a was then brought into close contact with the recess 12c and the protrusion 12d, thereby allowing a portion of the resin member 20 to fill the recess 12c and align with the protrusion 12d, thereby forming the second strong bond 42. Other components of the present Example 10 that are equivalent to those of Example 9 are designated by the same reference numerals, and their description will be omitted.

[0069] 16 , in Example 10, the second strong bond portion 42 is formed in the region where the electrodeposition coating film 30a is formed. Even in this case, a part of the airtight bond portion 30 is located more inward of the second strong bond portion 42 in the resin member 20. In other words, the second strong bond portion 42 is formed more outward (toward the second surface 22) than a part of the airtight bond portion 30. Thus, Example 10 having this configuration can also achieve the same effects as Example 9. Note that the first strong bond portion 41 may be formed in the region where the electrodeposition coating film 30a is formed, and a part of the airtight bond portion 30 may be located more inward of the first strong bond portion 41 in the resin member 20.

[0070] The present invention is not limited to the above examples, and can be applied to various embodiments within the scope of the present invention. [Explanation of symbols]

[0071] 1 Metal-resin joint 10 Metallic parts 11 1st junction area 12 Second joint area 13 Thickness direction extension region 11a, 12a through hole 11b, 12b uneven shape 20 Resin parts 21 First Side 22 Second Side 30 Airtight joint 30a Electrodeposition coating 40 Strong joint 41 1st strong joint 42 2nd strong joint

Claims

1. A metal-resin joined body formed by joining a metal member and a resin member through which a part of the metal member penetrates from a first surface to a second surface, The joint between the metal member and the resin member includes an airtight joint portion that joins the metal member and the resin member to each other and is made of an electrodeposition coating film that prevents gas from passing between the metal member and the resin member, and a strong joint portion that joins the metal member and the resin member to each other with a joint strength higher than the joint strength at the airtight joint portion, the airtight joint is formed over the entire circumferential area of ​​the metal member in at least a part of a region where the metal member penetrates the resin member, The strong joint portion includes a first strong joint portion located closer to the first surface of the resin member than at least a portion of the airtight joint portion, and a second strong joint portion located closer to the second surface of the resin member than at least a portion of the airtight joint portion.

2. the resin member has a plate shape, and a pair of main surfaces of the resin member constitute the first surface and the second surface; 2. The metal-resin joint body according to claim 1, wherein the metal member has a thickness-direction extending region that extends in the thickness direction of the resin member in a region that penetrates the resin member and is joined to the resin member via the airtight joint, and a first joint region that extends from the thickness-direction extending region toward the first surface, bends parallel to the first surface, and is joined to the first surface via the first strong joint.

3. the resin member has a plate shape, and a pair of main surfaces of the resin member constitute the first surface and the second surface; 2. The metal resin joint body according to claim 1, wherein the metal member has a thickness-direction extending region that extends in the thickness direction of the resin member in a region that penetrates the resin member and is joined to the resin member via the airtight joint, and a first joint region that extends from the thickness-direction extending region toward the first surface, bends parallel to the first surface, is covered by the resin member, and is joined to the resin member via the first strong joint.

4. 4. The metal-resin joined body according to claim 2 or 3, wherein the metal member further has a second joining region extending from the thickness direction extending region toward the second surface, bending parallel to the second surface, and joining to the second surface of the resin member via the second strong joining portion.

5. 4. The metal-resin joint body according to claim 2, wherein the metal member further has a second joining region that extends from the thickness direction extending portion toward the second surface, is bent parallel to the second surface, is covered with the resin member, and is joined to the resin member via the second strong joining portion.

6. 6. The metal-resin bonded body according to claim 4, wherein the first bonding region and the second bonding region of the metal member sandwich a part of the resin member in a thickness direction.

7. 7. The metal-resin bonded body according to claim 1, wherein at least one of the first strong bonding portion and the second strong bonding portion is formed by the resin member being in close contact with an uneven shape formed by roughening the surface of the metal member.

8. 8. The metal-resin bonded body according to claim 1, wherein at least one of the first strong bonding portion and the second strong bonding portion is formed by closely adhering the resin member along an uneven shape or a through hole formed by laser processing, press processing, or mechanical processing of the metal member.

9. 9. The metal resin joined body according to claim 1, wherein the resin member is formed by insert molding using the metal member provided with the electrodeposition coating film as an insert.

10. The resin member is made of engineering plastic or super engineering plastic, 10. The metal-resin joined body according to claim 1, wherein the electrodeposition coating film is made of an epoxy resin, a polyamide-imide resin, or a polyimide resin.

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