Method for molding metal-resin composite material, and metal-resin composite component, and manufacturing method thereof
Patent Information
- Application Number
- JP2024016628
- Authority / Receiving Office
- JP · JP
- Patent Type
- Applications
- Current Assignee / Owner
- Filing Date
- 2024-02-06
- Publication Date
- 2025-02-14
- Estimated Expiration
- 2039-12-03
Smart Images
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Abstract
Description
[Technical field]
[0001] The present disclosure relates to a method for molding a metal-resin composite material, a metal-resin composite part, and a method for producing the same. [Background technology]
[0002] In recent years, with the growing interest in environmental issues, environmentally friendly automobiles equipped with secondary batteries, such as electric automobiles and hybrid automobiles, are becoming more and more popular. Many of these environmentally friendly automobiles use a system in which a direct current generated from an on-board secondary battery is converted to an alternating current via an inverter, and the necessary power is then supplied to an AC motor to obtain driving force. For this reason, electromagnetic waves are generated due to the switching operation of the inverter. Since electromagnetic waves can interfere with on-board sensors, a measure has been taken to shield electromagnetic waves by housing the inverter or the battery and motor together with the inverter in a housing made of an aluminum plate material having a predetermined coating film on the surface (Patent Document 1). [Prior art documents] [Patent documents]
[0003] [Patent Document 1] JP 2003-285002 A Summary of the Invention [Problem to be solved by the invention]
[0004] In recent years, materials used for electromagnetic wave shielding are required to be lightweight and to be able to be formed into complex shapes (particularly, to be able to be formed to fit a mold having a complex shape). However, it cannot be said that the aluminum sheet material described in Patent Document 1 satisfactorily meets the above requirements. On the other hand, methods for solving the above-mentioned requirements include a method of using an Al-deposited film in which aluminum is deposited on a resin film, and a method of applying electroless plating to a material with good formability. However, although the method of using an Al-deposited film is inexpensive and has good formability, the deposited Al layer has a small thickness and low conductivity compared to copper foil, etc., so there is a problem that the electromagnetic wave shielding effect is insufficient. In addition, the method of applying electroless plating to a material with good formability has a problem that the electromagnetic wave shielding effect is insufficient because it is expensive and it is difficult to increase the thickness of the plating layer.
[0005] Therefore, the inventors focused on a metal-resin composite material in which a metal layer and a resin layer are laminated, and attempted to solve the above-mentioned requirements while ensuring the electromagnetic wave shielding effect by optimizing the configurations of the metal layer and the resin layer. However, although metal-resin composite materials have a good electromagnetic wave shielding effect, there is a problem that springback is likely to occur in the bent portion (flange portion) during molding (for example, bulging or drawing), making it difficult to fully obtain the desired dimensional accuracy.
[0006] An embodiment of the present invention has been made to solve the above problems, and has an object to provide a molding method for a metal-resin composite material that can suppress springback. Another object of the embodiments of the present invention is to provide a metal-resin composite part with high dimensional accuracy and a manufacturing method thereof. [Means for solving the problem]
[0007] The inventors conducted intensive research to solve the above problems, and as a result, based on the knowledge that the laminate structure of a metal-resin composite material and the direction of application of a pressing force during molding are related to the occurrence of springback, they discovered that the springback suppression effect can be improved by molding a metal-resin composite material having a specific laminate structure by applying a pressing force in a specific direction, and have thus completed an embodiment of the present invention.
[0008] That is, an embodiment of the present invention is a method for molding a metal-resin composite material having a laminated structure in which a metal layer and a resin layer are alternately laminated, and the laminated structure is asymmetric, divide the metal-resin composite material into part a and part b at a position half of the total layer thickness of the metal-resin composite material, and define the total layer thickness of the resin layer existing in part a as Tra, the total layer thickness of the metal layer existing in part a as Tma, the total layer thickness of the resin layer existing in part b as Trb, and the total layer thickness of the metal layer existing in part b as Tmb, when Tma / Tra > Tmb / Trb, perform molding with part a arranged on the surface to which the pressing force is applied, when Tma / Tra < Tmb / Trb, perform molding with part b arranged on the surface to which the pressing force is applied, when Tma / Tra = Tmb / Trb, perform molding with the side where the metal layer is located on the surface layer or the side closer to the metal layer among part a or part b arranged on the surface to which the pressing force is applied. This is a method for molding a metal-resin composite material.
[0009] Also, an embodiment of the present invention is a method for manufacturing a metal-resin composite part, including the above method for molding a metal-resin composite material.
[0010] Furthermore, an embodiment of the present invention is a metal-resin composite part formed from a metal-resin composite material having a laminated structure in which a metal layer and a resin layer are alternately laminated, and the laminated structure is asymmetric, divide the metal-resin composite material into part a and part b at a position half of the total layer thickness of the metal-resin composite material, and define the total layer thickness of the resin layer existing in part a as Tra, the total layer thickness of the metal layer existing in part a as Tma, the total layer thickness of the resin layer existing in part b as Trb, and the total layer thickness of the metal layer existing in part b as Tmb, when Tma / Tra > Tmb / Trb, part a is arranged on the surface to which the pressing force is applied, when Tma / Tra < Tmb / Trb, part b is arranged on the surface to which the pressing force is applied, When Tma / Tra=Tmb / Trb, the side of part a or part b on which the metal layer is located on the surface or the side closest to the metal layer is located on the surface to which the pressing force is applied, which is a metal resin composite part. Effect of the Invention
[0011] According to an embodiment of the present invention, a method for molding a metal-resin composite material capable of suppressing springback can be provided. Furthermore, according to the embodiment of the present invention, it is possible to provide a metal-resin composite part with high dimensional accuracy and a method for manufacturing the same. [Brief description of the drawings]
[0012] [Figure 1] FIG. 2 is a cross-sectional view of a metal resin composite material having a two-layer structure of a metal layer / a resin layer. [Diagram 2] FIG. 2 is a cross-sectional view of a metal resin composite material having a three-layer structure of metal layer / resin layer / metal layer. [Diagram 3] FIG. 2 is a cross-sectional view of a metal resin composite material having a four-layer structure of metal layer / resin layer / metal layer / resin layer. [Figure 4] FIG. 13 is a diagram for explaining a method of applying a pressing force F in drawing. [Diagram 5] 1 is a photograph of the molded products formed in Example 1 and Comparative Example 1. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0013] Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the drawings, but the present invention should not be interpreted as being limited thereto, and various modifications and improvements can be made based on the knowledge of those skilled in the art without departing from the gist of the present invention. The multiple components disclosed in this embodiment can be appropriately combined to form various inventions. For example, some components may be deleted from all the components shown in this embodiment, or components of different embodiments may be appropriately combined.
[0014] In the method for molding a metal resin composite material according to an embodiment of the present invention, molding is performed by applying a pressing force from a specific direction depending on the type of layered structure of the metal resin composite material. The metal-resin composite material has a laminated structure in which metal layers and resin layers are alternately laminated. The metal-resin composite material having such a structure has an electromagnetic wave shielding effect, and can be used as an electromagnetic wave shielding material.
[0015] The number of layers in the laminated structure of the metal resin composite material is not particularly limited as long as it is 2 or more, but is preferably 2 to 15 layers, more preferably 2 to 10 layers, and further preferably 2 to 8 layers. Examples of the laminated structure include a two-layer structure of metal layer / resin layer, a three-layer structure of resin layer / metal layer / resin layer or metal layer / resin layer / metal layer, a four-layer structure of resin layer / metal layer / resin layer / metal layer or metal layer / resin layer / metal layer / resin layer, etc. The laminate structure of a metal resin composite material is asymmetric. When the number of layers of a metal resin composite material is an even number, the laminate structure is asymmetric. On the other hand, when the number of layers of a metal resin composite material is an odd number (excluding 1), the laminate structure is asymmetric or symmetric. An example of a symmetric laminate structure is when the first and third layers of a three-layer structure have the same thickness. Another example of an asymmetric laminate structure is when the first and third layers of a three-layer structure have different thicknesses. Moreover, the laminated structure of the metal resin composite material preferably has two or more metal layers, which increases the number of reflective surfaces for electromagnetic waves, thereby improving the electromagnetic wave shielding effect.
[0016] The method for molding a metal-resin composite material according to an embodiment of the present invention is carried out as follows. In the laminated structure of the metal resin composite material, the metal resin composite material is divided into two parts, part a and part b, at a position halfway through the total layer thickness. The total layer thickness of the resin layers present in part a is Tra, the total layer thickness of the metal layers present in part a is Tma, the total layer thickness of the resin layers present in part b is Trb, and the total layer thickness of the metal layers present in part b is Tmb. Thereafter, the direction of application of the pressing force is determined according to each of the following cases (1) to (3), and molding is performed. (1) When Tma / Tra > Tmb / Trb, perform molding with the a - part side placed on the surface to which the pressing force is applied. (2) When Tma / Tra < Tmb / Trb, perform molding with the b - part side placed on the surface to which the pressing force is applied. (3) When Tma / Tra = Tmb / Trb, perform molding with the side where the metal layer is located on the surface layer or the side closer to the metal layer among the a - part or b - part placed on the surface to which the pressing force is applied. By performing molding while applying the pressing force as described above, the occurrence of springback can be suppressed.
[0017] Here, a cross - sectional view of the metal - resin composite material corresponding to the case of (1) is shown in FIG. 1. FIG. 1 is a cross - sectional view of a metal - resin composite material having a two - layer structure of a metal layer 10 / resin layer 20. When the metal - resin composite material is divided into an a - part and a b - part at the position of half of the total layer thickness, Tra, Tma, and Trb can be determined as shown in FIG. 1. In the metal - resin composite material of FIG. 1, since it has a two - layer structure, Tmb is zero. However, if it has a laminated structure of three or more layers, Tmb can be set to be greater than zero. Since the metal - resin composite material of FIG. 1 satisfies the relationship of Tma / Tra > Tmb / Trb, molding is performed with the a - part side placed on the surface to which the pressing force F is applied.
[0018] Next, a cross - sectional view of the metal - resin composite material corresponding to the case of (2) is shown in FIG. 2. FIG. 2 is a cross - sectional view of a metal - resin composite material having a three - layer structure of a metal layer 10 / resin layer 20 / metal layer 10. When the metal - resin composite material is divided into an a - part and a b - part at the position of half of the total layer thickness, Tra, Tma, Tmb, and Trb can be determined as shown in FIG. 2. In the metal - resin composite material of FIG. 2, the thicknesses of the two metal layers 10 are different, and the thickness of the metal layer 10 in the b - part is set to be larger than the thickness of the metal layer 10 in the a - part. Since the metal - resin composite material of FIG. 2 satisfies the relationship of Tma / Tra < Tmb / Trb, molding is performed with the b - part side placed on the surface to which the pressing force F is applied.
[0019] Next, a cross-sectional view of a metal-resin composite material corresponding to the case (3) is shown in FIG. Fig. 3 is a cross-sectional view of a metal resin composite material having a four-layer structure of metal layer 10 / resin layer 20 / metal layer 10 / resin layer 20. When the metal resin composite material is divided into parts a and b at a position halfway through the total layer thickness, Tra, Tma, Tmb and Trb can be determined as shown in Fig. 3. In the metal resin composite material of Fig. 3, the two metal layers 10 and the two resin layers 20 have the same thickness. The metal resin composite material in FIG. 3 satisfies the relationship Tma / Tra=Tmb / Trb, and since the metal layer 10 is located on the surface layer of the part a, the part a is placed on the surface to which the pressing force F is applied during molding.
[0020] The molding method of the metal-resin composite material is not particularly limited as long as it is a method capable of applying a pressing force F to a predetermined surface, and any method known in the art can be used. Examples of molding methods include drawing, stretching, bending, and compressed air molding. Among these, drawing is preferred because of its excellent workability into complex shapes. When the molding method is drawing, the pressing force F is applied by a punch. Here, as an example, a method of applying a pressing force F in drawing will be described with reference to FIG. 4. When the surface to which the pressing force F is applied is the part a side of the metal resin composite material, the part a side of the metal resin composite material is placed on the surface that comes into contact with the punch 30 that applies the pressing force F. Then, the punch 30 is pressed against the metal resin composite material in the thickness direction to form it, thereby obtaining a molded body (metal resin composite part) having a predetermined shape. Although not shown, the metal resin composite material is placed in a die, and the peripheral portion is fixed by a blank holder, and then forming is performed by the punch 30. Furthermore, molding of the metal-resin composite material can be carried out at room temperature or in a warm state, but even when molding is carried out at room temperature, the occurrence of springback can be suppressed. The magnitude of the pressing force F may be appropriately adjusted depending on the molding method used, the thickness of the metal-resin composite material, and the like, and is not particularly limited.
[0021] It is preferable that the metal resin composite material has a metal layer 10 disposed on the surface to which the pressing force F is applied. With this configuration, when the metal resin composite material is molded to produce an electromagnetic wave shielding housing, the inner surface of the electromagnetic wave shielding housing becomes the metal layer 10, making it easy to ground the housing.
[0022] The material of the metal layer 10 is not particularly limited, and various metals can be used. Among them, from the viewpoint of enhancing the electromagnetic shielding effect against AC magnetic fields and AC electric fields, a metal with excellent electrical conductivity can be used. Specifically, the electrical conductivity of the metal used for the metal layer 10 is preferably 1.0×10 6 S / m (value at 20°C, same below) or more, preferably 10.0×10 6 S / m or more, more preferably 30.0×10 6 S / m or more, most preferably 50.0×10 6 Such highly conductive metals have a conductivity of about 9.9×10 S / m or more. 6 S / m of iron, conductivity is about 14.5×10 6 S / m of nickel, conductivity is about 39.6×10 6 S / m of aluminum, conductivity is about 58.0×10 6 S / m of copper, conductivity is about 61.4×10 6 Examples of suitable metals include silver having a conductivity of 1.0 S / m. Among these, aluminum or copper is preferable in terms of practicality, taking into consideration both electrical conductivity and cost. In addition, an alloy of the above-mentioned metals may be used for the metal layer 10. When a plurality of metal layers 10 are present in the metal-resin composite material, the plurality of metal layers 10 may be the same or different.
[0023] The surface of the metal layer 10 may be formed with various surface treatment layers for the purpose of improving adhesion promotion, environmental resistance, heat resistance, rust prevention, and the like. For example, in order to improve the environmental resistance and heat resistance required when the metal surface is the outermost layer, an Au plating layer, an Ag plating layer, an Sn plating layer, a Ni plating layer, a Zn plating layer, an Sn alloy plating layer (such as an Sn-Ag layer, an Sn-Ni layer, or an Sn-Cu layer), a chromate treatment layer, or the like, may be formed on the surface of the metal layer 10. These treatment layers may be single or multiple. Among these treatment layers, it is preferable to form an Sn plating layer or an Sn alloy plating layer from the viewpoint of cost. In order to improve the adhesion between the metal layer 10 and the resin layer 20, a chromate-treated layer, a roughening-treated layer, a Ni-plated layer, or the like may be formed on the surface of the metal layer 10. These treatment layers may be formed singly or in combination. Among these treatment layers, the roughening-treated layer is preferred because it is highly effective in improving adhesion. Furthermore, for the purpose of improving the electromagnetic wave shielding effect against a DC magnetic field, a layer with high relative magnetic permeability may be provided on the surface of the metal layer 10. Examples of the layer with high relative magnetic permeability include an Fe-Ni alloy plating layer and a Ni plating layer.
[0024] When a copper foil layer is used as the metal layer 10, it is preferable that the purity is high from the viewpoint of improving the electromagnetic wave shielding effect. The purity of the copper foil used for the copper foil layer is preferably 99.5 mass % or more, and more preferably 99.8 mass % or more. The copper foil can be rolled copper foil, electrolytic copper foil, metallized copper foil, etc., but rolled copper foil is preferred because it has excellent flexibility and formability. When alloy elements are added to the copper foil to make the copper alloy foil, the total content of these elements and unavoidable impurities should be less than 0.5 mass%. In particular, it is preferable that the copper foil contains at least one selected from the group consisting of Sn, Mn, Cr, Zn, Zr, Mg, Ni, Si, and Ag in a total of 200 to 2000 mass ppm, since this improves the elongation compared to pure copper foil of the same thickness.
[0025] The thickness of the metal layer 10 is not particularly limited, but is 10 μm or more, preferably 15 μm or more, more preferably 20 μm or more, even more preferably 25 μm or more, and particularly preferably 30 μm or more per layer. By making the thickness of the metal layer 10 10 μm or more, it is possible to sufficiently ensure the electromagnetic wave shielding effect. In addition, the thickness of the metal layer 10 is preferably 100 μm or less, more preferably 50 μm or less, even more preferably 45 μm or less, and particularly preferably 40 μm or less per layer. By making the thickness of the metal layer 10 100 μm or less, it is possible to suppress the deterioration of the moldability. When a plurality of metal layers 10 are present in the metal-resin composite material, the thicknesses of the plurality of metal layers 10 may be the same or different.
[0026] The material of the resin layer 20 is not particularly limited, and various resins can be used. Examples of the resin include PET (polyethylene terephthalate) resin, PEN (polyethylene naphthalate) resin, PI (polyimide) resin, PC (polycarbonate) resin, PE (polyethylene) resin, and PP (polypropylene) resin. Since all of these resins have a relatively large springback, when the molding method according to the present disclosure is applied using these resins, the springback can be effectively suppressed. Among the above-mentioned resins, PET resin, which is inexpensive, is preferable. When a plurality of resin layers 20 are present in the metal-resin composite material, the plurality of resin layers 20 may be the same or different.
[0027] The thickness of the resin layer 20 is not particularly limited, but is preferably 10 μm or more, more preferably 20 μm or more, even more preferably 30 μm or more, and particularly preferably 40 μm or more per layer. By making the thickness of the resin layer 20 10 μm or more, when a housing is manufactured from a metal-resin composite material, the strength of the housing can be ensured. Moreover, the thickness of the resin layer 20 is preferably 300 μm or less, more preferably 200 μm or less, and even more preferably 150 μm or less per layer. Moreover, by making the thickness of the resin layer 20 300 μm or less, the deterioration of moldability can be suppressed. When a plurality of resin layers 20 are present in the metal-resin composite material, the thicknesses of the plurality of resin layers 20 may be the same or different, but are preferably the same.
[0028] The resin layer 20 can be formed using a resin film, but may also be formed by directly applying a resin material onto the metal layer 10 and curing it. When a resin film is used as the resin layer 20, the method for bonding the metal layer 10 and the resin film is not particularly limited, and any method known in the art can be used. For example, the metal layer 10 and the resin film may be bonded by thermocompression bonding, or the metal layer 10 and the resin film may be bonded using an adhesive. However, since it is difficult to thermocompress a resin film such as a PET resin film to the metal layer 10, it is preferable to bond them using an adhesive.
[0029] The adhesive is not particularly limited, and known adhesives such as thermoplastic adhesives and thermosetting adhesives can be used. Among them, thermosetting adhesives are chemically stable, and therefore can prevent deterioration of the adhesive portion over time. Here, the thermoplastic adhesive refers to an adhesive mainly composed of a thermoplastic resin that softens when heated and hardens when cooled. The thermoplastic resin is not particularly limited, but may be polyvinyl acetate, vinyl acetate-vinyl chloride copolymer, polyvinyl butyral, α-olefin resin, cellulose resin, acrylic resin, vinyl chloride resin, polyvinyl acetal, etc. These may be used alone or in combination of two or more. The thermosetting adhesive refers to an adhesive mainly composed of a thermosetting resin that hardens when heated. The thermosetting resin is not particularly limited, but may be urea resin, melamine resin, phenolic resin, resorcinol resin, epoxy resin, structural acrylic resin, polyester resin, polyurethane resin, etc. These may be used alone or in combination of two or more kinds.
[0030] The total layer thickness of the metal resin composite material is not particularly limited, but is preferably 110 to 800 μm, more preferably 150 to 700 μm, still more preferably 200 to 600 μm, and particularly preferably 250 to 500 μm. By setting the total layer thickness of the metal resin composite material to 110 μm or more, the strength as a housing can be ensured when manufacturing a housing from the metal resin composite material. Also, by setting the total layer thickness of the metal resin composite material to 800 μm or less, a decrease in moldability can be suppressed.
[0031] The molding method of the metal resin composite material according to the embodiment of the present invention can be used in the manufacturing method of metal resin composite parts. Therefore, this manufacturing method of metal resin composite parts includes the molding method of the metal resin composite material according to the embodiment of the present invention. Here, in this specification, "metal resin composite part" means a part obtained by molding a metal resin composite material into a predetermined shape. The metal resin composite parts are not particularly limited, but include various parts that require electromagnetic wave shielding characteristics. Among them, the metal resin composite part is preferably an electromagnetic wave shielding housing.
[0032] The metal resin composite part according to the embodiment of the present invention manufactured as described above has a laminated structure in which the metal layer 10 and the resin layer 20 are alternately laminated, and is formed from a metal resin composite material in which the laminated structure is asymmetric. Further, the metal resin composite part according to the embodiment of the present invention is divided into part a and part b at the position half of the total layer thickness of the metal resin composite material, and when the total layer thickness of the resin layer 20 existing in part a is Tra, the total layer thickness of the metal layer 10 existing in part a is Tma, the total layer thickness of the resin layer 20 existing in part b is Trb, and the total layer thickness of the metal layer 10 existing in part b is Tmb, it has any one of the following structures (1) to (3). (1) When Tma / Tra > Tmb / Trb, the a part side is arranged on the surface to which the pressing force F is applied. (2) When Tma / Tra < Tmb / Trb, the b part side is arranged on the surface to which the pressing force F is applied. (3) When Tma / Tra=Tmb / Trb, the side of part a or part b on which metal layer 10 is located on the surface or the side close to metal layer 10 is placed on the surface to which pressing force F is applied. By using the above-described structure, the occurrence of springback during molding of the metal-resin composite material can be suppressed, thereby improving the dimensional accuracy of the metal-resin composite part.
[0033] The details of the metal-resin composite material forming the metal-resin composite part are as described above, and therefore will not be described here. EXAMPLES
[0034] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples in any way.
[0035] <Preparation of metal-resin composite material A> A two-layered metal resin composite material A (hereinafter, this laminated structure may be abbreviated as "Cu / PET") was produced by laminating rolled copper foil (thickness 17 μm) with a roughened layer formed on the surface and a PET resin film (thickness 100 μm). A thermosetting adhesive was used to bond the rolled copper foil and the PET resin film. In this metal resin composite material A, the rolled copper foil side is the a part side, and the PET resin film side is the b part side.
[0036] <Preparation of metal-resin composite material B> A two-layered metal resin composite material B (hereinafter, this laminated structure may be abbreviated as "Cu / PET") was produced by laminating rolled copper foil (thickness 18 μm) with a roughened surface layer formed on it and a PET resin film (thickness 100 μm). A thermosetting adhesive was used to bond the rolled copper foil and the PET resin film. In this metal resin composite material B, the rolled copper foil side is the a part side, and the PET resin film side is the b part side.
[0037] <Preparation of metal-resin composite material C> A two-layered metal resin composite material C (hereinafter, this laminated structure may be abbreviated as "Cu / PET") was produced by laminating rolled copper foil (thickness 35 μm) with a roughened layer formed on the surface and a PET resin film (thickness 100 μm). A thermosetting adhesive was used to bond the rolled copper foil and the PET resin film. In this metal resin composite material C, the rolled copper foil side is the a part side, and the PET resin film side is the b part side.
[0038] <Preparation of metal-resin composite material D> A six-layered metal-resin composite material D (hereinafter, this laminated structure may be abbreviated as "Cu / PET / Cu / PET / Cu / PET") was fabricated by alternately laminating three rolled copper foils (thickness 18 μm) with roughened layers formed on the surface and three PET resin films (thickness 100 μm). A thermosetting adhesive was used to bond the rolled copper foils and the PET resin films. In this metal-resin composite material D, the rolled copper foil side exposed on the surface is called side a, and the PET resin film side exposed on the surface is called side b.
[0039] <Preparation of metal-resin composite material E> A six-layered metal resin composite material E (hereinafter, this laminated structure may be abbreviated as "Cu / PET / Cu / PET / Cu / PET") was produced by alternately laminating three rolled copper foils (thickness 18 μm) with roughened layers formed on the surface and three PET resin films (thickness 50 μm). A thermosetting adhesive was used to bond the rolled copper foils and the PET resin films. In this metal resin composite material E, the rolled copper foil side exposed on the surface is called the a part side, and the PET resin film side exposed on the surface is called the b part side.
[0040] <Preparation of metal-resin composite material F> Two rolled copper foils (thickness 35 μm) and two PET resin films (thickness 50 μm) with a roughened treatment layer formed on the surface were alternately laminated to produce a metal-resin composite material F with a four-layer structure (hereinafter, this laminated structure may be abbreviated as "Cu / PET / Cu / PET"). For the adhesion between the rolled copper foil and the PET resin film, a thermosetting adhesive was used. In this metal-resin composite material F, the side of the rolled copper foil exposed on the surface layer is defined as the a-part side, and the side of the PET resin film exposed on the surface layer is defined as the b-part side.
[0041] Table 1 shows the values of Tma / Tra and Tmb / Trb calculated from the laminated structures of the metal-resin composite materials A to F produced as described above. In addition, the following evaluations were performed using the above metal-resin composite materials A to F.
[0042] <Forming processability> Using the above metal-resin composite materials A to F, a drawing process was performed to form a square tube with a flange angle of 90°. In the drawing process, for each of the metal-resin composite materials A to F, the a-part side and the b-part side were arranged on the surface to which the pressing force by the punch was applied, and the process was performed twice. In this evaluation, when comparing the results of the forming processability by the forming method using the same type of metal-resin composite material, a forming method with a smaller springback of the flange part is represented by ○, and a forming method with a larger springback is represented by ×. For example, as shown in FIG. 5, in the metal-resin composite material A, the molded product (metal-resin composite part) of Example 1 formed with the a-part side arranged on the surface to which the pressing force by the punch was applied has a significantly smaller springback of the flange part than the molded product of Comparative Example 1 formed with the b-part side arranged on the surface to which the pressing force was applied. Therefore, the processing formability of the molded product of Example 1 was evaluated as ○, and the processing formability of the molded product of Comparative Example 1 was evaluated as ×, respectively.
[0043] <W-bending test> Test pieces measuring 10 mm in width and 60 mm in length were cut out from the above metal resin composite materials A to F. These test pieces were subjected to a 90° W-bend at room temperature with a processing speed of 900 mm / min, a bending radius of 0 mm, a load of 2 kN, and a holding time of 2 seconds at the bottom dead center. The angle of the bent part (center part) that forms the peak of the W-bent test piece was measured, and the deviation from 90° (90°-measured angle), i.e., the magnitude of springback, was determined. The results of the above evaluations are shown in Table 1.
[0044] [Table 1]
[0045] As shown in Table 1, the metal resin composite material A had a Tma / Tra>Tmb / Trb ratio. Therefore, the moldability and the results of the W-bend test were better in the case where the part a was placed on the pressing force application surface (Example 1) than in the case where the part b was placed on the pressing force application surface (Comparative Example 1). Since the metal resin composite material B had Tma / Tra>Tmb / Trb, the moldability and the results of the W-bend test were better when the material was molded by placing the part a on the surface to which the pressing force was applied (Example 2) than when the material was molded by placing the part b on the surface to which the pressing force was applied (Comparative Example 2). Since the metal resin composite material C had Tma / Tra>Tmb / Trb, the moldability and the results of the W-bend test were better when the material was molded by placing the part a on the surface to which the pressing force was applied (Example 3) than when the material was molded by placing the part b on the surface to which the pressing force was applied (Comparative Example 3).
[0046] Since metal resin composite material D had Tma / Tra>Tmb / Trb, the moldability and results of the W-bend test were better when molded by placing part a on the surface to which the pressing force was applied (Example 4) than when molded by placing part b on the surface to which the pressing force was applied (Comparative Example 4). Since the metal resin composite material E had Tma / Tra>Tmb / Trb, the moldability and the results of the W-bend test were better when the material was molded by placing the part a on the surface to which the pressing force was applied (Example 5) than when the material was molded by placing the part b on the surface to which the pressing force was applied (Comparative Example 5). In the metal resin composite material E, Tma / Tra=Tmb / Trb, and the metal layer was located on the surface layer on the a part side. Therefore, the moldability and the results of the W-bend test were better when the a part side was placed on the pressing force application surface (Example 6) than when the b part side was placed on the pressing force application surface (Comparative Example 6).
[0047] As can be seen from the above results, according to the embodiment of the present invention, it is possible to provide a molding method for a metal-resin composite material capable of suppressing springback. Also, according to the embodiment of the present invention, it is possible to provide a metal-resin composite part with high dimensional accuracy and a manufacturing method thereof. [Explanation of symbols]
[0048] 10 metal layer 20 Resin layer 30 Punch
Claims
1. A method for molding a metal-resin composite material having an asymmetric laminate structure in which metal layers and resin layers are alternately laminated, comprising the steps of: The resin layer is a PET resin layer, The metal resin composite material is divided into an a portion and a b portion at a position halfway through the entire layer thickness, and the total layer thickness of the resin layers present in the a portion is designated as Tra, the total layer thickness of the metal layers present in the a portion is designated as Tma, the total layer thickness of the resin layers present in the b portion is designated as Trb, and the total layer thickness of the metal layers present in the b portion is designated as Tmb, When Tma / Tra>Tmb / Trb, the part a is placed on the surface to which the pressing force is applied, and molding is performed. When Tma / Tra<Tmb / Trb, the b portion is placed on the surface to which the pressing force is applied, and molding is performed. A molding method for a metal-resin composite material, in which, when Tma / Tra = Tmb / Trb, the side to which a pressing force is applied is the side of part a or part b on which the metal layer is located as a surface layer or the side closest to the metal layer, and molding is performed.
2. A method for molding a metal resin composite material as described in claim 1, wherein the metal resin composite material has two or more of the metal layers.
3. A method for molding a metal-resin composite material having a laminate structure in which metal layers and resin layers are alternately laminated, the laminate structure being asymmetric, comprising: The metal-resin composite material has two or more of the metal layers, The metal resin composite material is divided into an a portion and a b portion at a position halfway through the entire layer thickness, and the total layer thickness of the resin layers present in the a portion is designated as Tra, the total layer thickness of the metal layers present in the a portion is designated as Tma, the total layer thickness of the resin layers present in the b portion is designated as Trb, and the total layer thickness of the metal layers present in the b portion is designated as Tmb, When Tma / Tra>Tmb / Trb, the part a is placed on the surface to which the pressing force is applied, and molding is performed. When Tma / Tra<Tmb / Trb, the b portion is placed on the surface to which the pressing force is applied, and molding is performed. A molding method for a metal-resin composite material, in which, when Tma / Tra = Tmb / Trb, the side to which a pressing force is applied is the side of part a or part b on which the metal layer is located as a surface layer or the side closest to the metal layer, and molding is performed.
4. A method for molding a metal resin composite material described in any one of claims 1 to 3, wherein the molding is performed at room temperature.
5. The method for molding a metal resin composite material according to any one of claims 1 to 4, wherein the molding is performed by drawing.
6. The method for molding a metal resin composite material according to any one of claims 1 to 5, wherein the metal layer is a copper foil layer.
7. The method for molding a metal resin composite material according to any one of claims 1 to 6, wherein the thickness of one of the metal layers is 10 to 50 µm.
8. The method for molding a metal resin composite material according to any one of claims 1 to 7, wherein the thickness of one of the resin layers is 20 to 200 µm.
9. The method for molding a metal resin composite material according to any one of claims 1 to 8, wherein the metal layer is disposed on a surface to which the pressing force is applied.
10. The method for molding a metal resin composite material according to any one of claims 1 to 9, wherein the metal layer and the resin layer are bonded to each other with an adhesive.
11. A method for producing a metal-resin composite part, comprising the method for molding a metal-resin composite material according to any one of claims 1 to 10.
12. A metal-resin composite part formed from a metal-resin composite material having a laminate structure in which metal layers and resin layers are alternately laminated, the laminate structure being asymmetric, The resin layer is a PET resin layer, The metal resin composite material is divided into an a portion and a b portion at a position halfway through the entire layer thickness, and the total layer thickness of the resin layers present in the a portion is designated as Tra, the total layer thickness of the metal layers present in the a portion is designated as Tma, the total layer thickness of the resin layers present in the b portion is designated as Trb, and the total layer thickness of the metal layers present in the b portion is designated as Tmb, When Tma / Tra>Tmb / Trb, the a-part side is disposed on the surface to which the pressing force is applied, When Tma / Tra<Tmb / Trb, the b-part side is disposed on the surface to which the pressing force is applied, A metal-resin composite part in which, when Tma / Tra=Tmb / Trb, the side of part a or part b on which the metal layer is located as a surface layer or the side closest to the metal layer is disposed on the surface to which a pressing force is applied.
13. A metal resin composite part as described in claim 12, wherein the metal resin composite material has two or more of the metal layers.
14. A metal-resin composite part formed from a metal-resin composite material having a laminate structure in which metal layers and resin layers are alternately laminated, the laminate structure being asymmetric, The metal-resin composite material has two or more of the metal layers, The metal resin composite material is divided into an a portion and a b portion at a position halfway through the entire layer thickness, and the total layer thickness of the resin layers present in the a portion is designated as Tra, the total layer thickness of the metal layers present in the a portion is designated as Tma, the total layer thickness of the resin layers present in the b portion is designated as Trb, and the total layer thickness of the metal layers present in the b portion is designated as Tmb, When Tma / Tra>Tmb / Trb, the a-part side is disposed on the surface to which the pressing force is applied, When Tma / Tra<Tmb / Trb, the b-part side is disposed on the surface to which the pressing force is applied, A metal-resin composite part in which, when Tma / Tra = Tmb / Trb, the side of part a or part b on which the metal layer is located as a surface layer or the side closest to the metal layer is disposed on the surface to which a pressing force is applied.
15. The metal resin composite part according to any one of claims 12 to 14, wherein the metal layer is a copper foil layer.
16. The metal resin composite part according to any one of claims 12 to 15, wherein a thickness of one of the metal layers is 10 to 50 µm.
17. The metal-resin composite part according to any one of claims 12 to 16, wherein one of the resin layers has a thickness of 20 to 200 µm.
18. The metal-resin composite part according to any one of claims 12 to 17, wherein the metal layer is disposed on a surface to which the pressing force is applied.
19. The metal-resin composite part according to any one of claims 12 to 18, wherein the metal layer and the resin layer are bonded to each other with an adhesive.
20. The metal-resin composite part according to any one of claims 12 to 19, which is an electromagnetic wave shielding housing.