Method for manufacturing a composite member of a plated metal and a resin, and the composite member

Abstract

To expand a variation of materials that can constitute a base material in a composite member made by joining a base material and resin.SOLUTION: A method (M10) for manufacturing a composite member (10) including a base material (11), a metal coating (12) covering the base material (11), and a resin (resin member 13) bonded to a surface of the metal coating (12) includes: a removal process (S12) of removing an oxide film (natural oxide film) covering the surface of the metal coating (12); a hot water treatment process (S13) of applying hot water treatment to the surface; and a bonding process (S14) of bonding the resin to the surface.SELECTED DRAWING: Figure 5

Description

Technical Field

[0001] The present invention relates to a composite member including a base material, a metal film covering at least a part of the base material, and a resin joined to the surface of the metal film.

Background Art

[0002] Patent Document 1 discloses a technique related to a composite member including an aluminum member having an aluminum hydroxide film formed on its surface and a resin member in direct contact with the surface of the aluminum member on which the aluminum hydroxide film is formed (see, for example, FIG. 1 of Patent Document 1).

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] However, when adopting the technique of Patent Document 1, the material constituting the base material is limited to aluminum.

[0005] One aspect of the present invention has been made in view of the above-described problems, and an object thereof is to expand the variation of materials that can constitute a base material in a composite member formed by joining a base material and a resin.

Means for Solving the Problems

[0006] In order to solve the above problems, a method for manufacturing a composite member according to a first aspect of the present invention is a method for manufacturing a composite member including a base material, a metal film covering at least a part of the base material, and a resin joined to the surface of the metal film. The method for manufacturing the composite member includes a removal step of removing an oxide film covering the surface of the metal film, a hot water treatment step of subjecting the surface on which the removal step has been performed to a hot water treatment, and a joining step of joining a resin to the surface on which the hot water treatment step has been performed.

[0007] In order to solve the above problems, a composite member according to a sixth aspect of the present invention includes a base material, a metal film covering at least a part of the base material, the metal film having a needle-like structure formed on the surface thereof by at least one of a metal hydroxide and an oxide constituting the metal film, and a resin joined to the surface of the metal film.

Advantages of the Invention

[0008] According to one aspect of the present invention, in a composite member formed by joining a base material and a resin, the variations in the materials that can constitute the base material can be expanded.

Brief Description of the Drawings

[0009]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Embodiments for Carrying Out the Invention

[0010] 〔First Embodiment〕 The composite member 10 according to the first embodiment of the present invention will be described with reference to FIGS. 1 to 4. FIG. 1 is a perspective view of the composite member 10. FIG. 2 is a cross-sectional view of the composite member 10, which is a cross-sectional view taken along the line A-A' shown in FIG. 1. FIG. 3 is a scanning electron microscope (SEM) image of the bonding region 122 of the composite member 10 before bonding the resin member 13. The upper SEM image has a magnification of 20,000 times, and the lower SEM image has a magnification of 40,000 times. Note that the state before bonding the resin member 13 means a state in which the hot water treatment step S13 shown in FIG. 5 is performed and the bonding step S14 shown in FIG. 5 is not performed. Note that the manufacturing method M10 of the composite member including the hot water treatment step S13 and the bonding step S14 will be described later in the second embodiment.

[0011] As shown in FIG. 1, the composite member 10 includes a base material 11, a metal film 12, and a resin member 13.

[0012] <Base Material and Metal Film> As shown in FIG. 1, the base material 11 is formed in a plate shape. In the present embodiment, high-tensile steel is used as the material constituting the base material 11. However, the material constituting the base material 11 is not limited to high-tensile steel and can be appropriately selected according to the application. The material constituting the base material 11 may be any of metal, glass, ceramic, and resin. That is, in the composite member 10, the base material 11 is not limited to the plated metal described in the name of the invention.

[0013] In the present embodiment, as shown in FIG. 1, a metal film 12 is formed on one of the pair of main surfaces constituting the base material 11. That is, in the present embodiment, one of the main surfaces, which is a part of the base material 11, is covered with the metal film 12. However, the region of the base material 11 covered by the metal film 12 only needs to include the bonding region 122, which is the region where the resin member 13 to be described later is bonded, and it may be a part of the surface of the base material 11 or the entire surface of the base material 11.

[0014] In the present embodiment, zinc is adopted as the material constituting the metal film 12. Also, in the present embodiment, the metal film 12 is formed on one of the main surfaces of the base material 11 by plating. However, the material constituting the metal film 12 only needs to be a metal and is not limited to zinc. Note that the material constituting the metal film 12 is preferably a material capable of forming the metal film 12 by plating. Also, the method of forming the metal film 12 on one of the main surfaces of the base material 11 is not limited to plating. That is, in the composite member 10, the metal film 12 is not limited to the plating or plating film described in the name of the invention.

[0015] As described above, in the present embodiment, a high-tensile steel sheet called SPFC780 plated with zinc is used as the base material 11 and the metal film 12. The thickness of the metal film 12 is not limited, but is typically 1 μm or more and 50 μm or less. In the present embodiment, the thickness of the metal film 12 is 25 μm.

[0016] <Resin member> As shown in FIG. 1, the resin member 13 is formed in a rectangular parallelepiped shape. In the present embodiment, polyphenylene sulfide (PPS) resin is used as the material constituting the resin member 13. However, the material constituting the resin member 13 is not limited to PPS resin as long as it is a resin, and can be appropriately selected according to the application. The material constituting the resin member 13 may be an engineering plastic, a super engineering plastic, or a fiber-reinforced plastic containing glass fiber, carbon fiber, or the like in addition to PPS resin. Further, the material constituting the resin member 13 may be a resin suitable as an adhesive. An example of a resin suitable as an adhesive is an epoxy resin.

[0017] <Bonding region> Hereinafter, when the main surface 121 of the metal film 12 is viewed from the normal direction of the main surface 121, the region where the metal film 12 and the resin member 13 overlap is called the bonding region 122. In FIG. 1, the bonding region 122 is illustrated by a virtual line (dashed double-dotted line).

[0018] In the second embodiment, reference is made to FIG. 5 for description. In the region including the bonding region 122 of the main surface 121, a removal step S12 using blasting and a hot water treatment step S13 are performed.

[0019] By performing the removal step S12 using blasting on the bonding region 122, the natural oxide film formed on the surface of the bonding region 122 is removed, and further, a micro-sized uneven structure 123 is formed on the surface of the bonding region 122 (see FIG. 2).

[0020] Also, by performing a hot water treatment step S13 after the removal step S12, a needle-like structure 124 composed of zinc hydroxide and oxide is formed on the surface of the concavo-convex structure 123 in the bonding region 122 (see FIG. 2). However, the needle-like structure 124 may be composed of zinc hydroxide and oxide, or may be composed of at least one of zinc hydroxide and oxide. Note that FIG. 3 shows a scanning electron microscope (SEM) image of the needle-like structure 124 formed on the surface of the concavo-convex structure 123 in the bonding region 122. The upper SEM image has a magnification of 20,000 times, and the lower SEM image has a magnification of 40,000 times.

[0021] When comparing zinc hydroxide and zinc oxide, zinc hydroxide has higher wettability with respect to the resin. Therefore, when the needle-like structure 124 is composed of zinc hydroxide and oxide, the bonding strength between the metal film 12 and the resin member 13 can be increased by increasing the proportion of hydroxide in the needle-like structure 124.

[0022] The resin member 13 is joined to the bonding region 122 by being injection-molded so that a part thereof overlaps the bonding region 122. When the resin constituting the resin member 13 is injected into the bonding region 122, the resin has fluidity. Therefore, the resin having fluidity is filled in the gaps of the needle-like structure generated by the hot water treatment step S13, and the injected resin eventually hardens (see FIG. 2). Thus, in the composite member 10, at least a part of the base material 11 is covered by the metal coating 12, and a resin member 13, which is a resin cured in a joining region 122 that is at least a part of the main surface 121 of the metal coating 12, is joined thereto. Therefore, the material constituting the base material 11 may be any material that can cover a part of the surface with the metal coating 12. That is, the material of the base material 11 may be any material that can form the metal coating 12 on the surface by a plating method. Accordingly, the material constituting the base material 11 is not limited to aluminum as in Patent Document 1, so in the composite member 10, the variations of the materials that can constitute the base material can be expanded. Further, in the composite member 10, even when at least a part of the main surface of the base material 11 is covered by the metal coating 12, an anchor effect can be obtained in the same manner as in the technique of Patent Document 1, so the joining strength between the metal coating 12 and the resin member 13 can be increased to the same level as in the technique of Patent Document 1.

[0023] (Arithmetic mean slope and root mean square slope) In the joining region 122, the arithmetic mean slope RΔa of the main surface 121 is preferably 0.10 or more and 0.60 or less, more preferably 0.15 or more and 0.55 or less, and particularly preferably 0.17 or more and 0.50 or less. Also, in the joining region 122, the root mean square slope RΔq of the main surface 121 is preferably 0.20 or more and 0.70 or less, more preferably 0.25 or more and 0.65 or less, and particularly preferably 0.27 or more and 0.60 or less.

[0024] Both the arithmetic mean slope RΔa and the root mean square slope RΔq are used as indices indicating how much slope there is in a narrow space.

[0025] The smaller the arithmetic mean slope RΔa, the more likely the bonding strength is to be small. When the arithmetic mean slope RΔa is 0.10 or more, a practical bonding strength of about 12 MPa can be obtained. When the arithmetic mean slope RΔa is 0.15 or more, a more practical bonding strength of about 20 MPa can be obtained. In particular, when the arithmetic mean slope RΔa is 0.17 or more, sufficient bonding strength can be obtained even for welding of structural parts such as automobiles. Also, if the arithmetic mean slope RΔa is 0.60 or less, the removal process S12 by blasting can be carried out. In particular, when the arithmetic mean slope RΔa is 0.55 or less, the removal process S12 by blasting can be easily carried out. When the arithmetic mean slope RΔa is 0.50 or less, roughening by blasting is even easier.

[0026] Similarly, in the case of the root mean square slope RΔq, the smaller the root mean square slope RΔq, the more likely the bonding strength is to be small. When the root mean square slope RΔq is 0.20 or more, a practical bonding strength of about 12 MPa can be obtained. When the root mean square slope RΔq is 0.25 or more, a more practical bonding strength of about 20 MPa can be obtained. In particular, when the root mean square slope RΔq is 0.27 or more, sufficient bonding strength can be obtained even for welding of structural parts such as automobiles. Also, if the root mean square slope RΔq is 0.70 or less, the removal process S12 by blasting can be carried out. In particular, when the root mean square slope RΔq is 0.65 or less, the removal process S12 by blasting can be easily carried out. When the root mean square slope RΔq is 0.60 or less, the removal process S12 by blasting can be even easier.

[0027] (Thickness of the layer composed of hydroxide and oxide) The thickness t (see Fig. 2) of the layer composed of hydroxide and oxide containing the needle-like structure 124 is preferably 50 nm or more and 2000 nm or less, and more preferably 100 nm or more and 1000 nm or less. In the present embodiment, the thickness t is 500 nm.

[0028] When the thickness t is less than 50 nm, it is difficult to obtain practical bonding strength. This is because the resulting anchor effect is small. On the other hand, when the thickness t exceeds 2000 nm, at least one of the hydroxide and oxide structures tends to take a porous structure instead of a needle-like structure. In that case, it becomes difficult for the resin to penetrate into the interior of the porous structure, so it is difficult to obtain practical bonding strength. This is also because the resulting anchor effect is small. Therefore, when the thickness t is 50 nm or more and 2000 nm or less, the structures of the hydroxide and oxide can be made into suitable needle-like structures for obtaining the anchor effect, and as a result, the bonding strength can be increased.

[0029] When the thickness t is less than 100 nm, the anchor effect is not sufficient and it is difficult to obtain practical bonding strength. Also, when the thickness t exceeds 1000 nm, the hydroxide film becomes brittle and is likely to break when a load is applied. Therefore, when the thickness t is 100 nm or more and 1000 nm or less, practical bonding strength can be ensured and it is possible to make it difficult for the hydroxide film to break that may be caused by the load.

[0030] <Use of the composite member> Examples of the use of the composite member 10 include structural members for automobiles (e.g., suspension members) and electrical components.

[0031] When the composite member 10 is used as part of a structural member, it is preferable to use a high-tensile steel sheet galvanized as the base material 11 and the metal film 12, and use engineering plastics or super engineering plastics as the material constituting the resin member 13.

[0032] In addition, when the composite member 10 is used as part of an electrical component, a component made of metal such as a terminal molded with resin can be considered. In this case, copper with a plating treatment applied to the surface is used as the base material 11 and the metal film 12, and any one of PPS (polyphenylene sulfide) resin, PBT (polybutylene terephthalate) resin, and PPA (polyphthalamide) resin is preferably used as the material constituting the resin member 13.

[0033] Simply molding a metal (e.g., copper) terminal with resin easily creates gaps at the interface between the metal and the resin, and moisture in the atmosphere easily enters through these gaps. Electrical components such as motors and power control units dislike moisture. Therefore, conventionally, in order to suppress the intrusion of moisture, an epoxy resin or the like has been used to further seal the interface between the terminal and the resin. In the composite member 10, due to the anchor effect, gaps are less likely to occur at the interface between copper and resin, so the sealing using an epoxy resin or the like can be omitted. That is, simply molding a metal component such as a terminal with resin can seal the inside of the mold and enhance airtightness.

[0034] <Modification Example> A composite member 20, which is a modification of the composite member 10, will be described with reference to FIG. 4. FIG. 4 is a cross-sectional view of the composite member 20, which is a modification of the composite member 10.

[0035] In the composite member 10, the resin member 13 formed by injection molding is joined to the joining region 122 of the metal film 12. In the composite member 20, two sets of high-tensile steel plates, namely the base material 11A and the metal film 12A, and the base material 11B and the metal film 12B, are used. The base material 11A and the metal film 12A, and the base material 11B and the metal film 12B are both configured in the same manner as the base material 11 and the metal film 12 of the composite member 10.

[0036] Furthermore, in the composite member 20, a resin member 13 that functions as an adhesive is interposed between the bonding region 122A in the metal coating 12A and the bonding region 122B in the metal coating 12B, thereby bonding the metal coating 12A and the resin member 13, and bonding the metal coating 12B and the resin member 13.

[0037] In this way, it can also be said that the composite member 20 is composed of composite members 10A and 10B, which are two sets of composite members 10 and have a common resin member 13. The composite member 20 configured in this way is also included in the scope of the present invention.

[0038] 〔Second Embodiment〕 The manufacturing method M10 of the composite member according to the second embodiment of the present invention will be described with reference to FIGS. 5 and 6. The left diagram in FIG. 5 is a flowchart of the manufacturing method M10 of the composite member. The right diagram in FIG. 5 is a cross-sectional view of the bonding region 122 after performing each of the steps S11 to S14 included in the manufacturing method M10 of the composite member shown in the left diagram. In the right diagram of FIG. 5, the illustration of the reference numeral "122" of the bonding region 122 is omitted. The reference numeral "122" is illustrated in the cross-sectional view of FIG. 2. FIG. 6 is a flowchart of a removal step S12A, which is a modification of the removal step S12 included in the manufacturing method M10.

[0039] Also, hereinafter, the manufacturing method M10 of the composite member will be simply referred to as the manufacturing method M10. The manufacturing method M10 can be suitably used for manufacturing the composite member 10 described in the first embodiment. The composite member 10 is a composite member including a base material 11, a metal coating 12 covering at least a part of the base material 11, and a resin member 13 bonded to a bonding region 122 that is at least a part of the surface of the metal coating 12.

[0040] In the present embodiment, the manufacturing method M10 will be described as manufacturing the composite member 10. As described in the first embodiment, a high-tensile steel plate is used as the base material 11.

[0041] As shown in FIG. 5, the manufacturing method M10 includes a plating step S11, a removal step S12, a hot water treatment step S13, and a bonding step S14.

[0042] <Plating step> The plating step S11 is a step of forming a metal film 12 on one main surface of the base material 11 using a plating method (see the cross-sectional view of "S11" in the right figure of FIG. 5).

[0043] In the present embodiment, one main surface, which is a part of the base material 11, is covered with the metal film 12. However, the region of the base material 11 covered by the metal film 12 only needs to include the bonding region 122 shown in FIG. 1, and it may be a part of the surface of the base material 11 or the entire surface of the base material 11.

[0044] In the present embodiment, zinc is adopted as the material constituting the metal film 12. However, the material constituting the metal film 12 only needs to be a metal and is not limited to zinc. In addition, the material constituting the metal film 12 is preferably a material capable of forming the metal film 12 using a plating method. However, the method of forming the metal film 12 on one main surface of the base material 11 is not limited to the plating method. In that case, step S11 can be said to be a metal film forming step rather than a plating step.

[0045] In addition, when using a metal plate (for example, a hot-rolled steel sheet plated with zinc) on which the metal film 12 is pre-formed on the surface of the base material 11 as the starting material of the manufacturing method M10, the plating step S11 can be omitted.

[0046] <Removal step> When the base material 11 and the metal film 12 are left in the atmosphere for a long time (for example, a period longer than 3 days), a natural oxide film is often formed on the main surface 121 of the metal film 12. The removal step S12 is a step of removing the natural oxide film covering the main surface 121, which is the surface of the metal film 12. Note that the natural oxide film is a form of oxide film.

[0047] In this embodiment, in the removal step S12, blasting is used to remove the native oxide film. By using blasting, while removing the native oxide film, a micro-sized concavo-convex structure 123 can be formed on the surface (see the cross-sectional view of "S12" in the right figure of Fig. 5). Therefore, a main surface 121 with high metal activity and a high anchor effect can be obtained by performing the subsequent hot water treatment step S13.

[0048] In the blasting process, it is preferable that the particle diameter of the injection material is 10 μm or more and 710 μm or less, more preferably 20 μm or more and 500 μm or less, and particularly preferably 30 μm or more and 300 μm or less. Also, the injection pressure is preferably 0.05 MPa or more and 2.0 MPa or less, more preferably 0.3 MPa or more and 1.5 MPa or less, and particularly preferably 0.5 MPa or more and 1.0 MPa or less.

[0049] When a natural oxide film of the metal (zinc in this embodiment) constituting the metal film 12 is formed on the main surface 121 of the metal film 12, by having the particle diameter of the spraying material be 10 μm or more, a micro-sized concavo-convex structure 123 can be formed on the main surface 121. Further, by having the particle diameter of the spraying material be 300 μm or less, the possibility that the metal film 12 is damaged due to the blasting process can be reduced. When adopting a particle diameter of the spraying material of 10 μm or more and 710 μm or less, by adopting an injection pressure of 0.05 MPa or more and 2.0 MPa or less, the natural oxide film can be removed by the blasting process, and a micro-sized concavo-convex structure 123 can be formed on the main surface 121, and the possibility that the metal film 12 is damaged can be reduced. The oxide film of the metal often has low wettability with respect to the resin. Therefore, by performing a hot water treatment after removing the natural oxide film, the bonding strength in the composite member 10 can be increased to the same level as in the technology of Patent Document 1. Examples of damage to the metal film 12 that may occur when the blasting process is performed under inappropriate conditions include the spraying material penetrating the metal film 12 and the metal film 12 peeling off from the main surface of the base material 11. Note that this condition in the blasting process is suitable when the thickness of the metal film 12 is 1 μm or more and 50 μm or less. By having the thickness of the metal film 12 be 1 μm or more, while forming a micro-sized concavo-convex structure 123, the possibility that the metal film 12 is damaged can be surely reduced. Note that the thickness of 50 μm is a typical upper limit value of the thickness of the metal film 12 produced using an electroplating method.

[0050] (Modification example of the removal process) Note that in a removal process S12A which is a modification example of the removal process S12, in order to remove the natural oxide film, an acid treatment can also be used instead of the blasting process (see FIG. 6). The removal process S12A includes an ultrasonic cleaning process S121 and an acid treatment process S122.

[0051] The ultrasonic cleaning process S121 is a process of ultrasonically cleaning the main surface 121 of the metal film 12.

[0052] The acid treatment step S122 is a step of performing acid treatment on the main surface 121. Note that the acid treatment is also called pickling. In this modified example, hydrochloric acid is used as the acidic solution used in the acid treatment. However, the acidic solution used in the acid treatment is not limited to hydrochloric acid and can be appropriately selected.

[0053] The main surface 121 of the metal film 12 from which the natural oxide film has been removed using acid treatment is likely to have a smaller uneven size compared to the main surface 121 from which the natural oxide film has been removed using blasting. Therefore, even when the film thickness of the metal film 12 is thin, the natural oxide film can be removed without damaging the metal film 12.

[0054] <Hot water treatment step> The hot water treatment step S13 is a step of performing hot water treatment on the main surface 121 on which the removal step S12 has been carried out. By carrying out the hot water treatment step S13, the zinc constituting the main surface 121 is hydroxylated or oxidized as shown by the following chemical formula. As a result, a needle-like structure composed of at least one of the hydroxide and oxide of zinc constituting the metal film 12 is formed on the main surface 121 where the concavo-convex structure 123 is formed (see the cross-sectional view of "S13" in the right figure of Fig. 5). The needle-like structure is shown in Fig. 3 as described in the first embodiment.

[0055] Zn + 2H 2 O → Zn(OH) 2 + H 2 Zn(OH) 2 → ZnO + H 2 O

[0056] The temperature of the water used in the hot water treatment step S13 is preferably 50°C or higher and 100°C or lower, more preferably 60°C or higher and 95°C or lower, and particularly preferably 70°C or higher and 90°C or lower. Also, the treatment time in the hot water treatment is preferably 10 seconds or longer and 100 minutes or shorter, more preferably 30 seconds or longer and 80 minutes or shorter, and particularly preferably 1 minute or longer and 60 minutes or shorter.

[0057] When the temperature of the water used in the hot water treatment step S13 is less than 50°C, at least one of the metal hydroxides and oxides that make up the metal film does not grow sufficiently. Therefore, the resulting anchor effect is reduced, making it difficult to increase the bonding strength. Also, hot water at 100°C or lower can be obtained under atmospheric pressure, so it can be easily realized.

[0058] Also, when the treatment time in the hot water treatment step S13 is less than 10 seconds, at least one of the metal hydroxides and oxides of the metal (zinc in this embodiment) that make up the metal film 12 does not grow sufficiently. Therefore, the resulting anchor effect is reduced, making it difficult to increase the bonding strength. Also, it was found that the thickness t (see FIG. 2) of the layer composed of at least one of the metal hydroxides and oxides of the metal that makes up the metal film 12 tends to saturate when the treatment time exceeds 100 minutes. Therefore, by setting the treatment time to 100 minutes or less, the hot water treatment can be efficiently carried out.

[0059] Also, the electrical conductivity of the water used in the hot water treatment step S13 is preferably 0.05 μS / cm or more and 10 μS / cm or less, more preferably 0.08 μS / cm or more and 5 μS / cm or less, and particularly preferably 0.1 μS / cm or more and 1 μS / cm or less.

[0060] A high electrical conductivity of the water means a high concentration of impurities (especially metal ions) contained in the hot water. When the electrical conductivity of the water exceeds 10 μS / cm (i.e., when the concentration of impurities is too high), the reproducibility of the shape and size of at least one of the zinc hydroxides and oxides formed by the hot water treatment tends to decrease. As a result, the bonding strength in the composite member 10 tends to decrease.

[0061] Also, the lower the electrical conductivity of water, the higher the above-described joint strength. However, it was found that the joint strength tends to saturate when the electrical conductivity is below about 0.05 μS / cm. Therefore, by setting the lower limit value of the preferable range of the electrical conductivity of water to 0.05 μS / cm, it is possible to prevent the cost for removing impurities contained in the hot water from being wasted.

[0062] <Bonding step> The bonding step S14 is a step of bonding the resin member 13 to the surface of the bonding region 122 where the hot water treatment step S13 has been performed. In the present embodiment, using the injection molding method, the resin member 13 is molded so that a part of the resin member 13 overlaps the bonding region 122. When the resin constituting the resin member 13 is injected into the bonding region 122, the resin has fluidity. Therefore, the resin having fluidity is filled in the gaps of the needle-like structure generated by the hot water treatment step S13, and the injected resin eventually hardens (see the cross-sectional view of "S14" in the right figure of FIG. 5). Therefore, in the composite member 10, even when at least a part of the main surface of the base material 11 is covered with the metal film 12, an anchor effect can be obtained in the same manner as in the technique of Patent Document 1, so the bonding strength between the metal film 12 and the resin member 13 can be increased to the same level as in the technique of Patent Document 1.

[0063] The method of bonding the resin member 13 to the surface of the bonding region 122 in the bonding step S14 is not limited to the injection molding method, and for example, it may be an induction heating pressure bonding molding method or a press molding method. Also, as described with reference to the composite member 20 in FIG. 4, a method using a resin that functions as an adhesive such as an epoxy resin may be used.

[0064] 〔Supplementary matters〕 The present invention is not limited to the above-described first and second embodiments, and various modifications are possible within the scope shown in the claims. Embodiments obtained by appropriately combining the technical means disclosed in different embodiments are also included in the technical scope of the present invention.

Examples

[0065] [First Embodiment and Second Embodiment] The effects of the first and second embodiments of the present invention will be described while comparing them with the first and second experimental examples.

[0066] In the first embodiment, the second embodiment, the first experimental example, and the second experimental example, a galvanized high-tensile steel sheet was used as the starting material for manufacturing the composite member. Therefore, the base material 11 is a high-tensile steel sheet, and the material constituting the metal coating 12 is zinc. The film thickness of the metal coating 12 made of zinc is 25 μm.

[0067] In the first embodiment, the composite member 10 was manufactured by implementing the manufacturing method M10 shown in FIG. 5. That is, in the removal step S12, the natural oxide film was removed using blasting. In addition, as the conditions in the blasting, a particle diameter of the injection material of 106 to 125 μm was adopted, and an injection pressure of 1.0 MPa was adopted. As the conditions of the hot water treatment in the hot water treatment step S13, a water temperature of 75°C was adopted, and a treatment time of 40 minutes was adopted. As a result, the thickness t (see FIG. 2) of the layer composed of hydroxides and oxides including the needle-like structure 124 was 500 nm. In the joining step S14, the resin member 13 made of PPS resin was directly joined to the joining region 122 of the metal coating 12 that had undergone the hot water treatment step S13 using an injection molding method. As the conditions of the injection molding, a mold temperature of 140°C was adopted, a resin temperature of 260°C was adopted, an injection speed of 10 mm / second was adopted, a holding pressure of 50 MPa was adopted, and a holding time of 10 seconds was adopted.

[0068] In the second embodiment, based on the manufacturing method M10, the removal step S12A shown in FIG. 6 was implemented instead of the removal step S12. That is, in the second embodiment, acid treatment was used to remove the natural oxide film formed on the surface of the metal coating 12. In this acid treatment, a hydrochloric acid solution with a concentration of 10% was used as the hydrochloric acid solution for immersing the high-tensile steel sheet. The treatment time of the acid treatment was set to 10 seconds.

[0069] In the first experimental example, the hot water treatment step S13 was omitted based on the first embodiment. Similarly, in the second experimental example, the hot water treatment step S13 was omitted based on the second embodiment.

[0070] Using the composite members manufactured using the first embodiment, the second embodiment, the first experimental example, and the second experimental example configured as described above, the bonding strength (shearing strength) was measured by a test method conforming to ISO 19095.

[0071] Table 1 below shows the points of the first embodiment, the second embodiment, the first experimental example, and the second experimental example, and the shearing strength of each composite member.

[0072]

Table 1

[0073] In the first experimental example in which the natural oxide film was removed using blasting and the hot water treatment step S13 was omitted, a shearing strength of 14 MPa was obtained for the composite member. This shearing strength was significantly lower compared to the shearing strength of 31 MPa obtained by the first embodiment.

[0074] In the second experimental example in which the natural oxide film was removed using acid treatment and the hot water treatment step S13 was omitted, the resin member peeled off from the high-tensile steel plate immediately after the bonding step S14 was carried out. That is, a bonding defect was observed in the composite member manufactured using the second experimental example.

[0075] 〔Third Embodiment and Fourth Embodiment〕 Based on the first and second embodiments, the embodiments using the press molding method instead of the injection molding method in the joining step S14 are the third and fourth embodiments. In the press molding in the third and fourth embodiments, the resin member 13 made of carbon fiber reinforced thermoplastic resin (CFRTP manufactured by Toray Coating) was directly joined to the joining region 122 of the metal film 12. As the press molding conditions, a molding temperature of 220 ° C, a molding pressure of 5 MPa, and a holding time of 5 minutes were adopted.

[0076] Also, based on each of the third and fourth embodiments, the ones in which the hot water treatment step S13 was omitted were respectively the third experimental example and the fourth experimental example.

[0077] Using the composite members manufactured using the third embodiment, the fourth embodiment, the third experimental example, and the fourth experimental example configured as described above, the joining strength (shearing strength) was measured by a test method referring to JIS K6850 "Tensile Shear Adhesion Strength Test". The width of the joining region 122 is 25 mm, and the length of the joining region 122 is 12.5 mm.

[0078] Table 2 below shows the shearing strengths in the third embodiment, the fourth embodiment, the third experimental example, and the fourth experimental example.

[0079]

Table 2

[0080] In the third experimental example in which the natural oxide film was removed using blasting and the hot water treatment step S13 was omitted, a shearing strength of 16 MPa was obtained in the composite member. This shearing strength was significantly lower compared to the shearing strength of 32 MPa obtained by the third embodiment.

[0081] In the fourth experimental example in which the natural oxide film was removed using acid treatment and the hot water treatment step S13 was omitted, the resin member peeled off from the high-tensile steel plate immediately after the joining step S14 was performed. That is, in the composite member manufactured using the fourth experimental example, a joining defect was observed.

Explanation of Signs

[0082] 10, 10A, 10B Composite member 11, 11A, 11B Base material 12, 12A, 12B Metal coating 121 Main surface 122, 122A, 122B Joining region 123 Concavo-convex structure 124 Needle-like structure 13 Resin member (resin) 20 Composite member

Claims

1. A method for manufacturing a composite member including a base material, a metal film covering at least a part of the base material, and a resin joined to the surface of the metal film, comprising: a removing step of removing an oxide film covering the surface of the metal film; a hot water treatment step of subjecting the surface after the removing step to a hot water treatment; a joining step of joining a resin to the surface after the hot water treatment step, characterized in that it is a method for manufacturing a composite member.

2. The removing step is a step of blasting the surface, wherein in the blasting, the particle diameter of the injection material is 10 μm or more and 710 μm or less, and the injection pressure is 0.05 MPa or more and 2.0 MPa or less. The method for manufacturing a composite member according to claim 1, characterized in that.

3. The removing step is a step of subjecting the surface to an acid treatment. The method for manufacturing a composite member according to claim 1, characterized in that.

4. In the hot water treatment step, the temperature of water is 50°C or more and 100°C or less, and the treatment time is 10 seconds or more and 100 minutes or less. The method for manufacturing a composite member according to any one of claims 1 to 3, characterized in that.

5. In the hot water treatment step, the electrical conductivity of water is 0.05 μS / cm or more and 10 μS / cm or less. The method for manufacturing a composite member according to any one of claims 1 to 4, characterized in that.

6. a base material, a metal film covering at least a part of the base material, wherein a needle-like structure formed of at least one of a metal hydroxide and an oxide constituting the metal film is provided on the surface; a resin joined to the surface of the metal film, characterized in that it is a composite member.

7. The arithmetic mean slope of the surface is 0.10 or more and 0.60 or less. The composite member according to claim 6, characterized in that.

8. The root mean square slope of the surface is 0.20 or more and 0.70 or less. The composite member according to claim 6 or 7, characterized in that.

9. The thickness of the layer composed of at least one of the hydroxide and the oxide including the needle-like structure is 50 nm or more and 2000 nm or less. The composite member according to any one of claims 6 to 8, characterized in that.

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