Method for manufacturing joined body

Abstract

In this method for manufacturing a joined body (1), a first member (10) comprising a metal and a second member (20) comprising a resin are joined via an adhesive layer (30) comprising an electrodeposition coating film, the adhesive layer (30) hermetically sealing a gap between the first member (10) and the second member (20). The airtightness between the first member (10) and the second member (20) due to the adhesive layer (30) is 1 × 10-10 Pa·m3 / sec or less in He leak amount. The method comprises: an adhesive layer forming step of, after a deposition film is formed on the surface of the first member (10) by electrodeposition coating and washing with water is performed, heating to a temperature below the curing temperature of the adhesive layer (30) to volatilize the moisture to form an uncured adhesive layer (30); a joining step of joining the second member (20) to the first member (10) by mutually dissolving the uncured adhesive layer (30) and a part of the material forming the second member (20) rendered flowable by heating; and a reheating step of heating, after the joining step, to a temperature equal to or higher than the heating temperature in the adhesive layer forming step and less than the curing temperature of the adhesive layer.

Description

Manufacturing method of the bonded body

[0001] The present invention relates to a method for producing a bonded body.

[0002] Metal materials are being replaced with resins in automobile parts, electrical and electronic products, and other industrial products, primarily to reduce weight. In recent years, not only is replacement with resin being the norm, but joints that utilize the properties of metal materials and resin components to suit the intended use are also being used.

[0003] In such a bonded structure, since dissimilar materials, i.e., metal and resin, are bonded together, there is a risk that sufficient adhesion between the two may not be achieved. Therefore, various methods for improving adhesion have been studied. For example, in the configuration disclosed in Patent Document 1, a laser beam is irradiated onto the bonding surface of the metal member with the resin member to form fine irregular irregularities, and the material of the resin member melted at the bonding surface penetrates into the irregularities, thereby directly bonding the metal member and the resin member and improving the adhesion between them.

[0004] Japanese Patent Application Publication No. 10-294024

[0005] However, in the configuration disclosed in Patent Document 1, the irregularities formed by irradiating the laser beam are minute and irregular, so the resin member may not reach the deepest part of the irregularities, forming a gap between the metal member and the resin member. Furthermore, this gap communicates with the outside, reducing the airtightness between the metal member and the resin member. Therefore, even if adhesion between the metal member and the resin member can be ensured, if higher airtightness is required, this requirement cannot be met. Therefore, there is room for improvement in achieving both high adhesion and high airtightness.

[0006] Furthermore, when joining metals together, it is necessary to interpose an insulating layer between them in order to electrically insulate them. In such cases, dissimilar materials are joined together, and there is still room for improvement in order to achieve both high adhesion and high airtightness, as in the above case.

[0007] The present invention has been made in view of the above background, and aims to provide a method for producing a bonded body having excellent adhesiveness and airtightness.

[0008] In one aspect of the present invention, a first member made of metal and a second member made of resin are joined via an adhesive layer made of an electrodeposition coating film, the first member and the second member are hermetically sealed by the adhesive layer, a compatible layer is formed between the second member and the adhesive layer, in which a first resin material constituting the second member and a second resin material constituting the adhesive layer are mutually compatible, and the airtightness between the first member and the second member due to the adhesive layer is such that the He leakage amount is 1×10 －１０ P.A.M. ３ / sec or less, the method for manufacturing a joined body includes: an adhesive layer forming step of forming a deposit film on the surface of the first member by electrodeposition coating, washing the deposit film with water, and then heating to a temperature below the curing temperature of the adhesive layer to volatilize the water and form the adhesive layer in an uncured state; a joining step of joining the second member to the first member by causing the uncured adhesive layer to dissolve with a part of the material of the second member that has been heated to have fluidity; and a reheating step of heating, after the joining step, to a temperature that is equal to or higher than the heating temperature in the adhesive layer forming step and lower than the curing temperature of the adhesive layer.

[0009] Another aspect of the present invention is a sealing device comprising a first member made of metal and a second member made of metal joined together via an adhesive layer made of an electrodeposition coating film, wherein the first member and the second member are hermetically sealed by the adhesive layer, the adhesive layer being formed by a first adhesive layer made of the electrodeposition coating film formed on the first member and a second adhesive layer made of the electrodeposition coating film formed on the second member being mutually dissolved, and the airtightness between the first member and the second member provided by the adhesive layer is such that the He leakage amount is 1×10 －１０ P.A.M. ３ / sec or less, the method for manufacturing a joined body includes an adhesive layer forming step of forming a precipitate film on the surfaces of the first member and the second member by electrodeposition coating, washing the precipitate film with water, and then heating to a temperature below the curing temperature of the first adhesive layer and the second adhesive layer to volatilize the moisture and form the first adhesive layer and the second adhesive layer in an uncured state; a bonding step of bonding the first member and the second member by causing the first adhesive layer and the second adhesive layer in an uncured state to be compatible with each other; and a reheating step of heating, after the bonding step, to a temperature equal to or higher than the heating temperature in the adhesive layer forming step and lower than the curing temperature of the first adhesive layer and the second adhesive layer.

[0010] According to the manufacturing method of the joined body of the one aspect, the adhesive layer is made of an electrodeposition coating film, and therefore can have excellent adhesiveness to both the first member made of metal and the second member made of resin. After the joining step of joining the first member and the second member via the adhesive layer, the joining layer can be heated to a temperature equal to or higher than the heating temperature in the adhesive layer forming step and lower than the curing temperature of the adhesive layer, thereby increasing the airtightness of the joining layer. As a result, the airtightness between the first member and the second member due to the adhesive layer can be increased to a value at which the He leak amount is 1×10 －１０ P.A.M. ３ This makes it possible to manufacture a bonded body having extremely excellent airtightness.

[0011] According to the manufacturing method of the joined body of the other aspect, the adhesive layer between the first member made of metal and the second member made of metal is formed by a mutually dissolving first adhesive layer made of an electrodeposition coating film formed on the first member and a second adhesive layer made of an electrodeposition coating film formed on the second member. Therefore, the adhesive layer can have excellent adhesiveness to both the first member and the second member. After the joining step of joining the first member and the second member via the adhesive layer, a reheating step of heating to a temperature equal to or higher than the heating temperature in the adhesive layer forming step and lower than the curing temperature of the first adhesive layer and the second adhesive layer is performed, whereby the airtightness between the first member and the second member due to the adhesive layer can be improved to a level where the He leak amount is 1×10 －１０ P.A.M. ３This makes it possible to manufacture a bonded body having extremely excellent airtightness.

[0012] As described above, the present invention can provide a method for producing a bonded body having excellent adhesiveness and airtightness.

[0013] 1(a) is a top view of a bonded body, (b) is a cross-sectional view taken along line Ib-Ib, and (c) is a perspective view of the bonded body in Example 1. FIG. 1(b) is a partially enlarged view. FIG. 2 is an enlarged view of the area indicated by symbol A in FIG. 2. FIG. 3 is a conceptual diagram for explaining conditions for a He leak test. FIG. 4 is a conceptual diagram for explaining a method for manufacturing a bonded body in Example 1. FIG. 5 is a conceptual diagram for explaining a method for manufacturing a bonded body in Modification 1. FIG. 6 is a perspective view of a bonded body in Modification 2, and (b) is a perspective view of a bonded body in Modification 3. FIG. 7 is a perspective view of a bonded body in Modification 4, and (b) is a longitudinal cross-sectional view of a bonded body in Modification 5. FIG. 8 is a longitudinal cross-sectional view of a bonded body in Modification 6, and (b) is a longitudinal cross-sectional view of a bonded body in Modification 7. FIG. 9 is a partially enlarged view of a longitudinal cross-section of a bonded body in Example 2. FIG. 1(a) is a perspective view of a bonded body, and (b) is a longitudinal cross-sectional view of a bonded body in Example 3. (a) A perspective view of a sealed container, (b) a partial enlarged view of the sealed container, and (c) a partial vertical cross-sectional view of the sealed container in Example 4. (a) A perspective view of a sealed container, (b) a partial enlarged view of the sealed container, and (c) a partial vertical cross-sectional view of the sealed container in Modification 9. (a) A perspective view of a sealed container, (b) a partial enlarged view of the sealed container, and (c) a partial vertical cross-sectional view of the sealed container in Modification 10. (a) A perspective view of a sealed container, (b) a partial enlarged view of the sealed container, and (c) a partial vertical cross-sectional view of the sealed container in Example 5. (a) A perspective view of a sealed container, (b) a partial enlarged view of the sealed container, and (c) a partial vertical cross-sectional view of the sealed container in Modification 11. A perspective view of a joined body in Example 6. (a) A conceptual diagram for explaining a method for manufacturing a joined body in Example 6.

[0014] Preferably, the first resin material forming the second member is an engineering plastic or a super engineering plastic, and the second resin material forming the adhesive layer is an epoxy resin, a polyamide-imide resin, or a polyimide resin. In this case, using an engineering plastic or a super engineering plastic as the first resin material can improve the insulating properties, heat resistance, chemical resistance, and mechanical properties of the second member. The epoxy resin, polyamide-imide resin, or polyimide resin used as the second resin material has good wettability and compatibility with thermally molten engineering plastics or super engineering plastics, and has surface characteristics 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 molten engineering plastics or super engineering plastics during molding. Therefore, by using the first resin material and the second resin material as described above, sufficient adhesion can be achieved between the first member and the adhesive layer and between the second member and the adhesive layer. Furthermore, since the second member and the adhesive layer are both resins, sufficient adhesion can be achieved between them. As a result, the airtightness between the first member and the second member can be further improved.

[0015] In this specification, engineering plastics refer to resin materials 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 materials with a heat resistance temperature of 150°C or higher among engineering plastics.

[0016] The second resin material is preferably an electrolytically activated electrodeposition paint. In this case, the adhesive layer is cured by an electrolytically activated curing system, which achieves both curability and stability of the adhesive layer, thereby further improving the adhesion and airtightness between the first and second members.

[0017] The portion of the first member covered by the electrodeposition coating film that forms the adhesive layer preferably includes an area with a surface roughness Ra of 5.0 μm or less. In this case, the portion of the first member covered by the electrodeposition coating film has a relatively smooth surface, which facilitates adhesion of the material forming the electrodeposition coating film that forms the adhesive layer on the first member. This prevents air from entering between the adhesive layer and the surface of the first member, further improving the airtightness between the first member and the second member.

[0018] It is preferable that the first member has a concave-convex portion or a groove portion, and the second member is fitted into the concave-convex portion or the groove portion. In this case, the second member fitted into the concave-convex portion or the groove portion serves as an anchor for the first member and can increase the area of ​​the joint between the first member and the second member, thereby improving the joint strength between the first member and the second member.

[0019] The unevenness or groove is preferably formed in a portion covered by the electrodeposition coating film that forms the adhesive layer, and the opening width of the unevenness or groove is preferably 100 μm or more. In this case, even if the material forming the adhesive layer is a resin material with low wettability, it can easily enter the unevenness or groove, thereby further improving the airtightness between the first member and the second member.

[0020] It is preferable that the first member has a through hole and the second member is inserted into the through hole. In this case, the second member inserted into the through hole serves as an anchor for the first member, thereby improving the bonding strength between the first member and the second member.

[0021] The diameter of the through hole is preferably equal to or greater than the thickness of the first member, which makes it easier for the material of the second member to enter the through hole, thereby improving the bonding strength between the first member and the second member.

[0022] The thickness of the compatibility layer is preferably in the range of 1.0 to 25 μm, which is thick enough to maintain the adhesiveness and airtightness between the resin member and the adhesive layer.

[0023] Example 1 An example of the joined body will be described below with reference to Figures 1 to 3. The joined body 1 of Example 1 is formed by joining a first member 10 and a second member 20 via an adhesive layer 30 made of an electrodeposition coating film. The first member 10 and the second member 20 are hermetically sealed by the adhesive layer 30. Furthermore, the airtightness between the first member 10 and the second member 20 provided by the adhesive layer 30 is such that the He leakage amount is 1 x 10 －１０ P.A.M. ３ / sec or less.

[0024] The joined body 1 of Example 1 will be described in detail below. In Example 1, a first member 10 made of metal and a second member 20 made of resin are used. As shown in FIGS. 1( a) to 1(c), the first member 10 made of metal penetrates the second member 20 made of resin. In Example 1, the second member 20 is plate-shaped with a predetermined thickness, but as shown in FIG. 1(c), its outer shape is not specified. In Example 1, the horizontal direction, which is one of the surface directions of the second member 20, is defined as X; the vertical direction, which is one of the surface directions of the second member 20 and perpendicular to the horizontal direction X, is defined as Y; and the height direction, which is the thickness direction of the second member 20 and perpendicular to the horizontal direction X and the vertical direction Y, is defined as Z.

[0025] 1. First Member 10 The first member 10 is made of a metal, such as copper or an aluminum alloy, and is made of copper in this example. In this example, the first member 10 is cylindrical, but is not limited thereto. As shown in FIG. 1( b), the central region of the outer surface of the first member 10 in the height direction Z, including the portion located within the through-hole 21 of the second member 20, forms a bonding surface 11 to which an adhesive layer 30 (described below) is bonded.

[0026] A part or the entire bonding surface 11 includes an airtight region 12 that ensures airtightness between the adhesive layer 30 and the bonding surface 11. The airtight region 12 has a relatively smooth surface. The airtight region 12 preferably has a surface roughness Ra of a predetermined value or less, for example, 5.0 μm or less, more preferably 3.0 μm or less. In this example, the entire bonding surface 11 is the airtight region 12.

[0027] 2. Adhesive Layer 30 Next, the adhesive layer 30 will be described in detail. As shown in FIGS. 1( a) to 1(c), the adhesive layer 30 is provided on the joining surface 11 of the first member 10, including the airtight region 12. The adhesive layer 30 is a resin coating formed by electrodeposition coating. A material that adheres better to the first member 10 than the resin material constituting the second member 20 (described below) can be used for the adhesive layer 30. For example, a thermosetting epoxy resin, polyamide-imide resin, or polyimide resin, which is a cationic electrodeposition paint, can be used as the material for the adhesive layer 30. In this example, an electrolytically activated electrodeposition paint is used as the thermosetting epoxy resin. As a result, in the airtight region 12, the adhesive layer 30 is configured to hermetically seal the gap between the second member 20 and the first member 10 and prevent the passage of gas. The airtightness provided by the adhesive layer 30 will be described in detail below.

[0028] As shown in Figure 2, the average thickness (T0) of the adhesive layer 30 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 30 μm. An average thickness of less than 10 μm is undesirable because it can cause uneven coating or areas that are not coated. Furthermore, an average thickness of more than 80 μm is unrealistic because it can take an excessive amount of time to form the layer.

[0029] 3. Second Member 20 Next, the second member 20 will be described in detail. In this Example 1, the second member is made of resin. While the shape of the second member 20 is not limited, in this Example 1, it is plate-shaped as shown in FIG. 1B. The resin material constituting the second member 20 is preferably a thermoplastic resin material to enable insert molding, as described below. Considering exposure to high temperatures during insert molding, the heat resistance temperature of the resin material is preferably 150°C or higher. Furthermore, to ensure compatibility and adhesion between the resin material of the second member 20 and the material forming the adhesive layer 30, it is preferable that the solubility parameters (SP values) of the two materials are similar. For example, in consideration of cases where the material forming the adhesive layer 30 is 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, a resin material with a solubility parameter (SP value) in the range of 9.5 to 15 can be used for the resin material of the second member 20.

[0030] For example, the resin material forming the second member 20 may be an engineering plastic such as nylon resin or polycarbonate resin, or a super engineering plastic such as polyphenylene sulfide (PPS) resin, polysulfone (PSF) resin, polyethersulfone (PES) resin, or polyamide-imide (PAI) resin. In this example, PPS resin is used as the resin material forming the second member 20. Alternatively, the second member 20 may be a carbon fiber reinforced plastic made of a carbon fiber material and a resin material, or a prepreg for forming a carbon fiber reinforced plastic. Alternatively, the second member 20 may be a sheet-shaped carbon fiber reinforced plastic or a laminate of multiple prepregs thereof.

[0031] As shown in Fig. 3, a compatibility layer 40 is formed between the second member 20 and the adhesive layer 30, resulting from the mutual compatibility of the two resin members. In reality, the boundaries between the compatibility layer 40 and the second member 20 and between the compatibility layer 40 and the adhesive layer 30 are unclear. However, in this embodiment, the boundary 41 between the compatibility layer 40 and the second member 20 is defined as the portion of the second member 20 where deterioration is observed that is closest to the adhesive layer 30 in the lateral direction X, and the boundary 42 between the compatibility layer 40 and the adhesive layer 30 is defined as the portion of the adhesive layer 30 where deterioration of the adhesive layer 30 is observed that is closest to the second member 20 in the lateral direction X. In Fig. 3, the boundaries 41 and 42 are indicated by dashed lines based on the above definitions.

[0032] As shown in Figure 3, the thickness T1 of the compatibility layer 40 is defined as the maximum width between the boundaries 41 and 42 in the horizontal direction X. The thickness T1 of the compatibility layer 40 is preferably within the range of 1.0 to 25 µm. If the thickness T1 of the compatibility layer 40 is thinner than the minimum value of the above range, the adhesion between the second member 20 and the adhesive layer 30 may be reduced. Furthermore, if the thickness T1 of the compatibility layer 40 is greater than the maximum value of the above range, it may take a long time to form the compatibility layer 40, which may reduce productivity.

[0033] 4. Evaluation Test The airtightness of the adhesive layer 30 in the bonded structure 1 of this example will be described in detail below. As described above, the airtightness of the adhesive layer 30 is evaluated by a He leak test. The He leak test was performed by an internal vacuum method (spray method). That is, as shown in FIG. 4 , a test specimen W of Example 1 or the comparative example was set in a He leak test fixture 100, and then He gas stored in a He cylinder 102 was sprayed onto the test specimen W using a He spray gun 103. A He leak detector 101 (manufactured by ULVAC, model number HELIOT 904) equipped with a monitor 101a was used to evacuate the test specimen W as indicated by arrow 104 to detect the amount of He leaking through the test specimen W. The pass criterion for the amount of He leak was 1.0 × 10 －１０ P.A.M. ３ / sec or less.

[0034] In the airtightness test of this example, the bonded body 1 of this example 1 was used as a sample, and as a comparative example, a bonded body in which the second member 20 was melted and bonded to the outer surface of the first member 10 without using an adhesive layer 30.

[0035] The adhesiveness of the adhesive layer 30 was also evaluated by the following tensile strength test. The tensile strength test was performed using an electronic tensile tester (manufactured by Yonekura Seisakusho, model number CATY-1005Z). In the bonded body 1 and the bonded body of the comparative example, the first member 10 and the second member 20 were chucked, and the first member 10 was pulled in the axial direction Y at a tensile speed of 25.4 mm / min until it broke, and the peak load was measured. Table 1 below shows the results of the He leak test and the tensile strength test.

[0036]

[0037] As shown in Table 1, the He leakage amount in the bonded body of the comparative example was 2.0×10 －７ P.A.M. ３ / sec, but the He leakage amount in the bonded body 1 of this Example 1 was 1.0×10 －１０ P.A.M. ３ / sec or less. This confirmed that the bonded body 1 of this Example 1 exhibited extremely high airtightness. Furthermore, the tensile strength of the bonded body 1 of this Example 1 was sufficiently high compared to the tensile strength of the bonded body of the comparative example, and it was confirmed that the bonded body 1 of this Example 1 exhibited high adhesiveness.

[0038] 5. Manufacturing Method A manufacturing method for the bonded body 1 of this example will be described below.

[0039] As shown in Figure 5(a), a first member 10 is prepared, and an adhesive layer formation step S1 is performed. In the adhesive layer formation step S1, an adhesive layer 30 is formed on the joining surface 11 of the first member 10, including the airtight region 12. In the adhesive layer formation step S1 of this example, a water-soluble thermosetting epoxy resin is applied to the first member 10 by electrodeposition coating, and the resin is heated in a temperature environment below the curing temperature of the epoxy resin to volatilize the moisture and dry, forming a semi-cured adhesive layer 30. Note that by performing electrodeposition coating after masking both end regions of the outer surface of the first member 10 other than the joining surface 11, the adhesive layer 30 is formed only on the joining surface 11.

[0040] In this example, the electrodeposition coating in the adhesive layer formation step S1 is performed as follows. First, the surface of the first member 10 is cleaned and degreased. Then, an electrodeposition coating bath is filled with a cationic epoxy resin-based electrolytically activated electrodeposition paint (manufactured by Nippon Paint Co., Ltd., model number Insulead 3030) adjusted to a solids concentration of 20%. The cleaned and degreased first member 10 is then immersed in the bath and an applied voltage of 200 V is applied for 3 minutes. The first member 10 is then removed from the bath, rinsed with water, and dried in a drying oven for 20 minutes at 130°C, which is below the curing temperature of the electrolytically activated electrodeposition paint. This volatilizes the water, forming an adhesive layer 30 consisting of a semi-cured epoxy resin coating (deposit film) with an average thickness of 50 μm.

[0041] Then, insert molding is performed in the joining step S2 shown in FIGS. 5( b) and 5(c). In the insert molding in the joining step S2, first, a mold divided into two halves, an upper mold 51 and a lower mold 52, is prepared as shown in FIG. 5(b). The upper mold 51 has a recess 52a that conforms to the outer shape of the upper portion of the first member 10, and the lower mold 52 has a recess 52a that conforms to the outer shape of the lower portion of the first member 10 and the second member 20. Then, as shown in FIG. 5(c), the first member 10, on which an adhesive layer 30 made of a semi-cured epoxy resin coating is provided, is set between the upper mold 51 and the lower mold 52. Then, PPS resin that has been heated to make it fluid is poured between the upper mold 51 and the lower mold 52 to form the second member 20. In this example, the resin is heated to 330°C to melt it and make it fluid. As a result, the first member 10 and the second member 20 are bonded to each other via the adhesive layer 30 between the first member 10 and the second member 20, thereby forming the bonded body 1 shown in FIG.

[0042] In this embodiment, after the formation of the bonded body 1 shown in Fig. 1, it is reheated (reheating step). The target temperature for the reheating can be, for example, a temperature equal to or higher than the drying temperature in the adhesive layer forming step S1 and lower than the curing temperature of the adhesive layer 30. The heating time can be, for example, within a range of 90 to 250 minutes.

[0043] 6. Effects Next, the effects of the manufacturing method of the joined body 1 of this example will be described in detail. According to the manufacturing method of the joined body 1 of this example, the adhesive layer 30 is made of an electrodeposition coating film, and therefore can have excellent adhesiveness to both the first member 10 and the second member 20. After the joining step of joining the first member 10 and the second member 20 via the adhesive layer 30, the joining layer can be heated to a temperature equal to or higher than the heating temperature in the adhesive layer forming step and lower than the curing temperature of the adhesive layer, thereby increasing the airtightness of the joining layer. As a result, the airtightness between the first member 10 and the second member 20 due to the adhesive layer 30 can be increased to a value at which the He leak amount is 1×10 －１０ P.A.M. ３ / sec or less, which is extremely excellent. As a result, the joined body 1 having extremely excellent airtightness can be manufactured.

[0044] Furthermore, the bonding surface 11, which is the portion of the first member 10 covered by the electrodeposition coating film that forms the adhesive layer 30, includes an airtight region 12 with a surface roughness Ra of 5.0 μm or less. This makes the bonding surface 11 a relatively smooth surface, making it easier for the material forming the adhesive layer 30 to adhere to the bonding surface 11. This prevents an air layer from entering between the adhesive layer 30 and the bonding surface 11 of the first member 10, further improving the airtightness between the first member 10 and the second member 20.

[0045] In this example, a compatibility layer 40 is formed between the second member 20 and the adhesive layer 30. The compatibility layer 40 is made of the first resin material constituting the second member 20 and the second resin material constituting the adhesive layer 30. This further improves the adhesion and airtightness between the second member 20 and the adhesive layer 30.

[0046] In this example, the thickness T1 of the compatible layer 40 is in the range of 1.0 to 25 μm, which is sufficient for the compatible layer 40 to maintain the adhesiveness and airtightness between the second member 20 and the adhesive layer 30.

[0047] In this example, the first resin material forming the second member 20 is an engineering plastic or a super engineering plastic, and the second resin material forming the adhesive layer 30 is an epoxy resin, a polyamide-imide resin, or a polyimide resin. Using an engineering plastic or a super engineering plastic as the first resin material improves the insulating properties, heat resistance, chemical resistance, and mechanical properties of the second member 20. The epoxy resin, polyamide-imide resin, or polyimide resin used as the second resin material has good wettability and compatibility with thermally molten engineering plastics or super engineering plastics, and has surface characteristics 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 molten engineering plastics or super engineering plastics during molding. Therefore, by using the first resin material and the second resin material as described above, sufficient adhesion is achieved between the first member 10 and the adhesive layer 30 and between the second member 20 and the adhesive layer 30. Furthermore, because the second member 20 and the adhesive layer 30 are both resins, sufficient adhesion is achieved between them. As a result, the airtightness between the first member 10 and the second member 20 can be further improved.

[0048] In this example, the second resin material forming the adhesive layer 30 is an electrolytically activated electrodeposition paint. This results in the adhesive layer 30 being cured by an electrolytically activated curing system, which achieves both curability and stability of the adhesive layer 30 and further improves the adhesion and airtightness between the first member 10 and the second member 20.

[0049] Furthermore, according to the manufacturing method of the bonded body 1 of this example, the second member 20 can be bonded to the first member 10 by causing the semi-cured adhesive layer 30 and a part of the second member 20 to be compatible with each other. As described above, the adhesive layer 30 provides an airtight seal between the first member 10 and the second member 20, and the He leakage amount is 1×10 －１０ P.A.M. ３ / sec or less, it is possible to exhibit extremely high airtightness.

[0050] In the manufacturing method of the bonded body 1 of this example, in the adhesive layer forming step S1, the uncured adhesive layer 30 is formed and then reheated. This can further improve the adhesion between the adhesive layer 30 and the second member 20.

[0051] Alternatively, prior to the adhesive layer formation step S1, the bonding surface 11 may be laser-processed or etched to form multiple recesses with a depth and opening width of 100 μm to 500 μm, thereby providing the airtight region 12. For example, as shown in Modification 1 in FIG. 6 , the recesses can be formed by irradiating the bonding surface 11 with laser light using a laser irradiation device 50. The recesses forming the airtight region 12 are appropriately sized to allow the adhesive layer 30 material to easily penetrate. This prevents an air layer from penetrating between the adhesive layer 30 and the bonding surface 11 of the first member 10, thereby further enhancing the airtightness between the first member 10 and the second member 20. Furthermore, the recesses can provide an anchoring effect for the second member 20, further enhancing the adhesion between the first member 10 and the second member 20.

[0052] In this embodiment, the first member 10 has a cylindrical shape, but is not limited to this and may have other shapes. For example, the first member 10 may have a plate shape as in Modification 2 shown in Fig. 7(a) or a square prism shape as in Modification 3 shown in Fig. 7(b). Modifications 2 and 3 also provide the same effects as those of the first embodiment.

[0053] Furthermore, as shown in Modification 4 in FIGS. 8( a) and 8(b), a disk-shaped flange portion 15 may be provided on the cylindrical first member 10 of Example 1, and the flange portion 15 may also be bonded to the upper surface of the second member 20 via an adhesive layer 30. In Modification 4, the lower surface of the flange portion 15, i.e., the surface of the flange portion 15 facing the second member 20, is also etched by laser light irradiation to form an airtight region 12. Modification 4 also achieves the same effects as Example 1, and the flange portion 15 can enlarge the joint between the first member 10 and the second member 20, thereby improving the joint strength and airtightness between them. Note that, as shown in Modification 5 in FIGS. 9( a) and 9(b), the shape of the first member 10 may be such that the portion above the flange portion 15 of the first member 10 in Modification 4 shown in FIGS. 8( a) and 8(b) is removed. Modification 5 also achieves the same effects as Modification 4.

[0054] Furthermore, in this Example 1, the first member 10 is inserted into the through hole 21 of the second member 20, but this is not limited to this. As shown in Modification Example 6 in Figure 10 (a), the plate-shaped first member 10 and the plate-shaped second member 20 may be arranged in parallel and joined together via an adhesive layer 30 in the area where they overlap in the thickness direction (height direction Z).

[0055] Furthermore, as in Modification 7 shown in Fig. 10(b), the first member 10 may have a concave-convex portion 13, and the second member 20 may be configured to fit into the concave-convex portion 13. In this case, the second member 20 fitting into the concave-convex portion 13 serves as an anchor for the first member 10 and can increase the area of ​​the joint between the two, thereby improving the joint strength between the first member 10 and the second member 20. The concave-convex portion 13 can be formed by press working or machining. Alternatively, the concave-convex portion 13 may be formed in a groove shape.

[0056] 10( b), the opening width W1 of the concave-convex portion (groove portion) 13 is set to 100 μm or more. This allows the material forming the adhesive layer 30, even if it is a resin material with low wettability, to easily enter the concave-convex portion (groove portion) 13, thereby further improving the airtightness between the first member 10 and the second member 20.

[0057] 10(c), the first member 10 may have a through hole 14, and the second member 20 may fit into the through hole 14. In this case, the second member 20 fitting into the through hole 14 serves as an anchor for the first member 10 and can increase the area of ​​the joint between the first member 10 and the second member 20, thereby improving the joint strength between the first member 10 and the second member 20.

[0058] 10( c), the diameter D of the through hole 14 is equal to or greater than the thickness T3 of the first member 10. This makes it easier for the material of the second member 20 to enter the through hole 14, thereby improving the bonding strength between the first member 10 and the second member 20.

[0059] As described above, according to the present embodiment 1 and the modifications 2 to 7, it is possible to provide the bonded body 1 having excellent adhesiveness and airtightness.

[0060] (Example 2) In the above-described Example 1, the airtight region 12 was formed over the entire joining surface 11 of the first member 10, but instead, in Example 2, as shown in Fig. 11 , the joining surface 11 of the first member 10 includes the airtight region 12 with high smoothness and a roughened surface region 16 that has been roughened and has a surface roughness greater than that of the airtight region 12. Since the other configurations are the same as those in Example 1, the same reference numerals as those in Example 1 are used and descriptions thereof will be omitted.

[0061] In Example 2, as described above, the joining surface 11 of the first member 10 includes the airtight region 12 and the roughened region 16, thereby improving the airtightness between the second member 20 and the first member 10 in the airtight region 12, which has high smoothness, and improving the adhesion between the second member 20 and the first member 10 in the roughened region 16. This further improves both the adhesion and the airtightness. Note that Example 2 also achieves the same effects as Example 1.

[0062] 12(a) and 12(b), in the joined body 1 of Example 3, the second member 20 is plate-shaped and has a through-hole 21, and the first member 10 is plate-shaped and overlaps the second member 20 so as to cover the through-hole 21. The second member 20 and the first member 10 are joined together at the overlapping portion of the first member 10 and the second member 20 via an adhesive layer 30, and the adhesive layer 30 prevents gas from passing between the second member 20 and the first member 10 at the through-hole 21. The other configurations are the same as in Example 1, and therefore the same reference numerals as in Example 1 are used and descriptions thereof will be omitted.

[0063] According to the joined body 1 of Example 3, by using the second member 20, whose through hole 21 is closed by the first member 10, as a lid for a storage container (not shown), the first member 10 is prevented from reducing the airtightness of the storage container, and therefore a storage container with excellent airtightness can be provided. Note that Example 3 also achieves the same effects as Example 1.

[0064] 13( a) to 13(c), in the joined body 1 of Example 4, the second member 20 is part of a sealed container 60 and has a cylindrical resin tubular portion 25 that forms an opening 61 of the sealed container 60. The first member 10 is cylindrical and is disposed coaxially with the resin tubular portion 25 inside the resin tubular portion 25. The outer peripheral surface 10a of the first member 10 is provided with an airtight region 12 and is bonded to the inner peripheral surface 25a of the resin tubular portion 25 via an adhesive layer 30, which prevents gas from passing between the inner peripheral surface 25a of the resin tubular portion 25 and the outer peripheral surface 10a of the first member 10. Other configurations are similar to those of Example 1 and Modification 4, and therefore the same reference numerals are used and descriptions thereof are omitted.

[0065] According to the joined body 1 of Example 4, the strength of the opening 61 of the sealed container 60 can be improved, and the joined surface 11 between the first member 10 and the second member 20 can be prevented from reducing the airtightness of the sealed container 60, thereby providing a sealed container 60 with excellent airtightness. The sealed container 60 can be used as a cylinder capable of storing a gas with a small molecular weight, such as hydrogen gas or helium gas. This Example 4 also achieves the same effects as those of Example 1 and Modified Example 4.

[0066] The first member 10 in this fourth embodiment may have a shape that does not include the flange portion 15 shown in FIGS. 13(a) to 13(c), as in Modification 9 shown in FIGS. 14(a) to 14(c). Furthermore, as in Modification 10 shown in FIGS. 15(a) to 15(c), a disk-shaped first member 10 having a through hole may be bonded to the upper end surface of a cylindrical second member 20 via an adhesive layer 30. In Modification 10, an airtight region 12 is formed on the lower surface 10c of the first member 10 that faces the upper end surface of the second member 20. These Modifications 6 and 6 also achieve the same effects as those of this fourth embodiment.

[0067] Example 5 As shown in FIGS. 16( a) to 16(c), in the joined body 1 of Example 5, the second member 20 includes a cylindrical resin portion 26 that constitutes a part of the sealed container 60 and defines an opening 61 of the sealed container 60. The cylindrical first member 10 is disposed coaxially with the resin portion 26 on the outside of the resin portion 26. The outer peripheral surface 26a of the resin portion 26 and the inner peripheral surface 10b of the first member 10 are bonded via an adhesive layer 30. The adhesive layer 30 prevents gas from passing between the outer peripheral surface 26a of the resin portion 26 and the inner peripheral surface 10b of the first member 10. In Example 5, an airtight region 12 is formed on the inner peripheral surface 10b of the first member 10. Other configurations are similar to those of Example 1, and therefore the same reference numerals as those of Example 1 are used, and their description will be omitted.

[0068] The bonded body 1 of Example 5 can also improve the strength of the opening 61 of the sealed container 60, and can prevent the bonding surface 11 between the first member 10 and the second member 20 from reducing the airtightness of the sealed container, thereby providing a sealed container 60 with excellent airtightness.

[0069] 17(a) to 17(c), the first member 10 in this fifth embodiment may be configured so that the first member 10 covers the upper end of the resin tubular portion 26. This 11th embodiment also provides the same advantageous effects as the fifth embodiment.

[0070] Example 6 Example 6 shown in Figure 18 is a joined body 1 in which a second member 20 made of metal is used and the second member 20 and a first member 10 made of metal are joined via an adhesive layer 30. In Example 6, as shown in Figure 19(a) , the first member 10 has a cylindrical shaft portion 17 and a disk-shaped flange portion 18 provided in the center of the shaft portion 17. A first adhesive layer 31 is provided on the joining surface 11, which is the back surface of the flange portion 18. The first adhesive layer 31 has a configuration equivalent to the adhesive layer 30 of Example 1 described above.

[0071] As shown in FIG. 19( a ), the second member 20 is plate-shaped and has a through hole 21. As indicated by arrow P, the shaft portion 17 of the first member 10 is inserted into the through hole 21. A second adhesive layer 32 is provided on the inner wall of the through hole 21 in the second member 20 and in a region surrounding the through hole 21 that faces the flange portion 18. The second adhesive layer 32 has a configuration equivalent to the adhesive layer 30 of Example 1 described above. As shown in FIGS. 19( b ) and 19 ( c ), the joining surface 22 of the second member 20, which is the portion covered by the electrodeposition coating film that forms the second adhesive layer 32, has a configuration equivalent to the joining surface 11 of Example 1 described above, and the joining surface 22 includes an airtight region 23 having a configuration equivalent to the airtight region 12 of Example 1 described above.

[0072] The joined body 1 of Example 6 is manufactured as follows. First, in the adhesive layer formation step S1 shown in FIG. 19( a), a deposit film is formed on the surfaces of the first member 10 and the second member 20 by electrodeposition coating. The deposit film is then washed with water, and the first adhesive layer 31 and the second adhesive layer 32 are heated to a temperature lower than the curing temperature of the first adhesive layer 31 and the second adhesive layer 32 to volatilize the moisture, thereby forming the uncured first adhesive layer 31 and the second adhesive layer 32. The electrodeposition coating in the adhesive layer formation step S1 is performed in the same manner as in Example 1 described above. Furthermore, as in Example 1, the first adhesive layer 31 and the second adhesive layer 32 are formed in a semi-cured state, and then reheated. Then, as shown by arrow P, the shaft portion 17 of the first member 10 is inserted into the through hole 21 of the second member 20.

[0073] 19(b), in a joining step S2, the shaft portion 17 of the first member 10 is inserted into the through hole 21 of the second member 20 and heated to cause the uncured first adhesive layer 31 and the second adhesive layer 32 to become compatible with each other, thereby joining the first member 10 and the second member 20. As a result, a compatible layer 33 is formed in the adhesive layer 30, and the joined body 1 shown in FIG. 18 is formed. Then, after the joined body 1 is formed, a reheating step is performed in the same manner as in Example 1.

[0074] According to the manufacturing method of the joined body 1 of this Example 6, the adhesive layer 30 between the first member 10 made of metal and the second member 20 made of metal is formed by the mutual dissolution of the first adhesive layer 31 made of an electrodeposition coating film formed on the first member 10 and the second adhesive layer 32 made of an electrodeposition coating film formed on the second member 20. Therefore, the adhesive layer 30 can have excellent adhesiveness to both the first member 10 and the second member 20. After the joining step of joining the first member 10 and the second member 20 via the adhesive layer 30, a reheating step is performed in which heating is performed to a temperature equal to or higher than the heating temperature in the adhesive layer forming step and lower than the curing temperature of the first adhesive layer 31 and the second adhesive layer 32, thereby improving the airtightness between the first member 10 and the second member 20 by the adhesive layer 30 so that the He leak amount is 1×10 －１０ P.A.M. ３ / sec or less, which is extremely excellent. As a result, the joined body 1 having extremely excellent airtightness can be manufactured.

[0075] Furthermore, in the joined body 1 of this Example 6, the first member 10 and the second member 20 are joined via an adhesive layer 30 made of a resin electrocoating film, so that they are electrically insulated from each other, and, as in the case of Example 1, both high adhesion and high airtightness are achieved between the first member 10 and the second member 20.

[0076] The present invention is not limited to the above-described examples and modifications, and can be applied to various embodiments within the scope of the present invention.

Claims

1. A first member made of metal and a second member made of resin are joined via an adhesive layer made of an electrodeposition coating film, the first member and the second member are hermetically sealed by the adhesive layer, a compatibility layer is formed between the second member and the adhesive layer, in which a first resin material constituting the second member and a second resin material constituting the adhesive layer are mutually compatible, and the adhesive layer provides airtightness between the first member and the second member such that the He leak amount is 1×10 －１０ P.A.M. ３ / sec or less, the method for producing a bonded body comprising: an adhesive layer forming step of forming a deposit film on a surface of the first member by electrocoating, washing the deposit film with water, and then heating to a temperature below a curing temperature of the adhesive layer to volatilize moisture and form the adhesive layer in an uncured state; a joining step of joining the second member to the first member by causing the adhesive layer in an uncured state to dissolve with a part of a material for forming the second member that has been heated to give it fluidity; and a reheating step of heating to a temperature equal to or higher than the heating temperature in the adhesive layer forming step and lower than the curing temperature of the adhesive layer after the joining step.

2. A method for manufacturing a joined body as described in claim 1, wherein the first resin material forming the second member is an engineering plastic or a super engineering plastic, and the second resin material forming the adhesive layer is an epoxy resin, a polyamide-imide resin or a polyimide resin.

3. The method for manufacturing a joint body according to claim 2, wherein the second resin material is an electrolytically activated electrodeposition paint.

4. A first member made of metal and a second member made of metal are joined via an adhesive layer made of an electrodeposition coating film, the first member and the second member are hermetically sealed by the adhesive layer, the adhesive layer is formed by a first adhesive layer made of an electrodeposition coating film formed on the first member and a second adhesive layer made of an electrodeposition coating film formed on the second member being mutually dissolved, and the airtightness between the first member and the second member by the adhesive layer is such that the He leak amount is 1 x 10 －１０ P.A.M. ３ / sec or less, the method for producing a bonded body comprising: an adhesive layer formation step of forming a precipitate film on surfaces of the first member and the second member by electrocoating, washing the precipitate film with water, and then heating to a temperature lower than the curing temperature of the first adhesive layer and the second adhesive layer to volatilize moisture and form the first adhesive layer and the second adhesive layer in an uncured state; a bonding step of bonding the first member and the second member by causing the first adhesive layer and the second adhesive layer to be compatible with each other; and a reheating step of heating, after the bonding step, to a temperature equal to or higher than the heating temperature in the adhesive layer formation step and lower than the curing temperature of the first adhesive layer and the second adhesive layer.

5. A method for manufacturing a joint body described in any one of claims 1 to 4, wherein the portion of the first member covered by the electrocoating film forming the adhesive layer includes an area having a surface roughness Ra of 5.0 μm or less.

6. A method for manufacturing a joint body according to any one of claims 1 to 4, wherein the first member has an uneven portion or a groove portion, and the second member fits into the uneven portion or the groove portion.

7. A method for manufacturing a joint body as described in claim 6, wherein the uneven portion or the groove portion is formed in a portion covered by the electrocoating coating film that forms the adhesive layer, and the opening width of the uneven portion or the groove portion is 100 μm or more.

8. A method for manufacturing a bonded body according to any one of claims 1 to 4, wherein the first member has a through hole, and the second member fits into the through hole.

9. The method for manufacturing a joint body according to claim 8, wherein the diameter of the through hole is equal to or greater than the thickness of the first member.

10. The method for producing a joint body according to any one of claims 1 to 3, wherein the thickness of the compatibility layer is within the range of 1.0 to 25 μm.

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