Metal member, metal-resin bonded body, and method for manufacturing metal-resin bonded body

Abstract

The present invention provides a metal member, a metal-resin joined body, and a method for manufacturing a metal-resin joined body, which are capable of firmly joining a synthetic resin member while ensuring airtightness. A metal member to be joined to a resin joining surface of a resin member having a synthetic resin satisfying the following formula (1), the metal member having a metal joining surface in contact with the resin joining surface, the metal joining surface having a roughened portion having a recess and a peripheral portion provided around the roughened portion, the oxidation number of a metal constituting the metal member being different between the roughened portion and the peripheral portion, and methylene iodide exhibits expansion wetting. [0010] TIFF0007587902000017.tif19139In equation (1), γ iod p is the polar component of the surface free energy of methylene iodide (mJ / m 2 )γ iod d is the dispersion component of the surface free energy of methylene iodide (mJ / m 2 ), γ p is the polar component of the surface free energy of the synthetic resin in the solid state (mJ / m 2 ), γ d is the dispersion component of the surface free energy of the synthetic resin in the solid state (mJ / m 2 ), γ is the sum of the polar component and the dispersive component of the surface free energy of the synthetic resin in a solid state (=γ p +γ d ).

Description

[Technical field]

[0001] The present invention relates to a metal member, a metal-resin bonded body, and a method for producing a metal-resin bonded body. [Background technology]

[0002] As a method for producing a metal-resin joined body by joining a metal member made of metal and a synthetic resin member made of synthetic resin, it has been proposed to increase the joining strength between the metal member and the synthetic resin member by forming an uneven roughened portion called an anchor on the surface of the metal member that comes into contact with the synthetic resin member (metal joining surface) (see, for example, Patent Document 1 below).

[0003] In order to obtain a strong bond in a metal-resin bonded body having a roughened portion on the metal joining surface, it is necessary to form an intricate roughened portion on the metal joining surface and fill the inside of the roughened portion with the synthetic resin that constitutes the synthetic resin member. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 5998303 Summary of the Invention [Problem to be solved by the invention]

[0005] However, it is difficult to fill the inside of the roughened portion with the synthetic resin that constitutes the synthetic resin member, and it is difficult to obtain a stable joint strength. If the inside of the roughened portion is not sufficiently filled with synthetic resin, the airtightness and liquid-tightness of the joint surface between the metal member and the synthetic resin member are reduced.

[0006] The present invention has been made in consideration of the above points, and an object of the present invention is to provide a metal member, a metal-resin bonded body, and a method for manufacturing a metal-resin bonded body that are capable of firmly bonding a synthetic resin member while ensuring airtightness and liquid-tightness at the bonding surface with the synthetic resin member. [Means for solving the problem]

[0007] According to this embodiment, the following aspects [1] to

[15] are provided.

[0008] [1] A metal member joined to a resin joining surface of a resin member having a synthetic resin satisfying the following formula (1), a metal joining surface in contact with the resin joining surface, The metal joining surface comprises a roughened portion having a recess and a peripheral portion provided around the roughened portion, and the oxidation number of the metal constituting the metal member is different between the roughened portion and the peripheral portion, so that methylene iodide exhibits expansion wetting.

[0009]

number

[0010] [2] A metal member joined to a resin joining surface of a resin member having a synthetic resin satisfying the following formula (2), a metal joining surface in contact with the resin joining surface, The metal joining surface comprises a roughened portion having a recess and a peripheral portion provided around the roughened portion, and the oxidation number of the metal constituting the metal member is different between the roughened portion and the peripheral portion, and pure water and methylene iodide are allowed to expand and wet the metal member.

[0011]

number

[0012] [3] The metal member according to [1] or [2] above, wherein the fractal dimension of the roughened portion determined by a box counting method through cross-sectional SEM observation is 2.1 or more and 3.0 or less.

[0013] [4] The metal member according to [1] or [2] above, wherein the roughened portion is provided in the form of grooves extending in a predetermined direction.

[0014] [5] A metal-resin joined body in which a metal joining surface of a metal member is brought into contact with a resin joining surface of a resin member having a synthetic resin that satisfies the following formula (3), thereby joining the metal member and the resin member, The metal resin joint body has a roughened portion having a recess and a peripheral portion provided around the roughened portion, and the oxidation number of the metal constituting the metal member is different between the roughened portion and the peripheral portion, and methylene iodide exhibits expansion wetting.

[0015]

number

[0016] [6] A metal-resin joined body in which a metal joining surface of a metal member is brought into contact with a resin joining surface of a resin member having a synthetic resin that satisfies the following formula (4), thereby joining the metal member and the resin member, The metal resin joint body has a roughened portion having a recess and a peripheral portion provided around the roughened portion, and the oxidation number of the metal constituting the metal member is different between the roughened portion and the peripheral portion, and pure water and methylene iodide are expanded to wet the metal resin joint body.

[0017]

number

[0018] [7] A method for producing a metal-resin joined body in which a metal joining surface of a metal member is brought into contact with a resin joining surface of a resin member having a synthetic resin that satisfies the following formula (5), thereby joining the metal member and the resin member, A method for manufacturing a metal-resin bonded body, comprising the steps of: forming a roughened portion having a recess on the metal bonding surface; and forming a peripheral portion around the roughened portion; and making the oxidation number of the metal constituting the metal member different between the roughened portion and the peripheral portion, thereby performing a process for expanding and wetting methylene iodide to the metal bonding surface.

[0019]

number

[0020] [8] A method for producing a metal-resin joined body, in which a metal joining surface of a metal member is brought into contact with a resin joining surface of a resin member having a synthetic resin that satisfies the following formula (6), and the metal member and the resin member are joined together, comprising: A method for manufacturing a metal-resin bonded body, comprising the steps of: forming a roughened portion having a recess on the metal bonding surface; and forming a peripheral portion around the roughened portion; and making the oxidation number of the metal constituting the metal member different between the roughened portion and the peripheral portion, thereby performing a process for expanding wettability of the metal bonding surface with pure water and methylene iodide.

[0021]

number

[0022] [9] A method for producing a metal resin joined body as described in [7] or [8] above, comprising: a first step of contacting the resin joining surface with the metal joining surface heated to a first temperature and pressurizing the metal member and the resin member at a first pressure; and a second step of pressing the metal member and the resin member at a second pressure higher than the first pressure while the metal joining surface is at a second temperature lower than the first temperature.

[0023]

[10] The method for producing a metal resin joined body according to the above [9], wherein, after the first step, heating of the metal joining surfaces is stopped or the amount of heating is reduced, and the pressure applied to the metal member and the resin member is changed from the first pressure to the second pressure, and then the second step is carried out.

[0024]

[11] When the first step is performed, after the temperature of the metal joining surface is lowered to the second temperature, The method for producing a metal resin bonded body according to the above-mentioned [9], wherein the second step is carried out by changing a pressure applied to the metal member and the resin member from the first pressure to the second pressure.

[0025]

[12] The method for producing a metal resin joined body according to any one of the above [9] to

[11] , wherein the first temperature is a temperature equal to or higher than a melting point of a resin material constituting the resin member.

[0026]

[13] The method for producing a metal-resin bonded body according to the above

[12] , wherein the first temperature is equal to or higher than the melting point of the resin material and equal to or lower than an upper limit temperature that is 20° C. higher than the melting point of the resin material.

[0027]

[14] The method for producing a metal-resin bonded body according to the above

[11] , wherein the second temperature is equal to or lower than a temperature 10° C. higher than the melting point of the resin material constituting the resin member.

[0028]

[15] The method for producing a metal resin joined body according to the above-mentioned

[14] , wherein the first temperature is equal to or higher than the melting point of the resin material and equal to or lower than an upper limit temperature that is 20°C higher than the melting point of the resin material, and the second temperature is equal to or lower than a temperature that is 10°C higher than the melting point of the resin material and equal to or higher than a lower limit temperature that is 20°C lower than the melting point of the resin material. Effect of the Invention

[0029] With the above-described configuration, the synthetic resin member can be firmly joined while ensuring airtightness at the joint surface with the synthetic resin member. [Brief description of the drawings]

[0030] [Figure 1] FIG. 1 is a cross-sectional view showing a schematic configuration of a metal-resin bonded body according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a plan view showing a schematic configuration of a joining surface of a metal member constituting the metal-resin joined body of FIG. [Diagram 3]FIG. 1 is a diagram showing a schematic configuration of a joining device used in a method for producing a metal-resin joined body according to an embodiment of the present invention, and shows a state in which a synthetic resin member 10 is placed on a metal joining surface 22. [Figure 4] FIG. 1 is a diagram showing a schematic configuration of a joining apparatus used in a method for producing a metal-resin joined body according to an embodiment of the present invention, and shows a state in which a synthetic resin member 10 is joined to a metal joining surface 22. [Diagram 5] SEM photograph of the metal bonding surface of the metal member in Example 1 [Figure 6] SEM photograph of a cross section of a metal member in Example 1 DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0031] Hereinafter, an embodiment of the present invention will be described with reference to the drawings. In the drawings, the size of the components may be exaggerated for the purpose of explanation. The present invention is not limited to the following embodiment. The following embodiment is presented as an example and is not intended to limit the scope of the invention. The novel embodiment can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the gist of the invention.

[0032] (1) Metal-resin bonded body 30 First, a description will be given of a metal-resin bonded body 30 manufactured by the manufacturing method of this embodiment. As shown in Fig. 1, the metal-resin bonded body 30 includes a synthetic resin member 10 made of synthetic resin and a metal member 20 made of metal.

[0033] One surface of the synthetic resin member 10 serves as a resin joining surface 12 that is joined to the metal member 20. One surface of the metal member 20 serves as a metal joining surface 22 that is joined to the resin joining surface 12 of the synthetic resin member 10. The metal-resin joined body 30 is obtained by joining the resin joining surface 12 of the synthetic resin member 10 and the metal joining surface 22 of the metal member 20 together.

[0034] (2) Synthetic resin material 10 The synthetic resin member 10 is a member obtained by molding synthetic resin into a predetermined shape such as a block, a plate, a line, etc. The synthetic resin member 10 may also be a synthetic resin coating film or an adhesive layer made of a synthetic resin adhesive.

[0035] As the synthetic resin constituting the synthetic resin member 10, various synthetic resins such as thermoplastic resins and thermosetting resins can be used. Specific examples include polypropylene resin (PP resin), polyoxymethylene resin (POM resin), polyphenylene sulfide resin (PPS resin), polyether ether ketone resin (PEEK), acrylonitrile / butadiene / styrene resin (ABS resin), polyethylene resin (PE resin), polybutylene terephthalate resin (PBT resin), polyamide resin (PA resin) such as nylon 6 resin (PA6 resin) and nylon 66 (PA66), epoxy resin (epoxy adhesive), liquid crystal polymer (LCP resin), modified polyphenylene ether resin (modified PPE), reactor type soft polypropylene resin (metallocene reactor type TPO resin), PE resin, etc. These include perfluoroalkoxyalkane resin (PFA resin), polyacrylamide resin (PAM resin), acrylic resin (PMMA resin), polycarbonate resin (PC resin), polyvinylidene fluoride resin (PVDF resin), polyvinylidene chloride resin (PVCD resin), polyphenylene sulfide resin (PPS resin), polyvinyl chloride resin (PVC resin), polyethylene terephthalate resin (PET resin), polyvinyl fluoride resin (PVF resin), polystyrene resin (PS resin), polyvinyl alcohol resin (PVA resin), paraffin resin, polytetrafluoroethylene resin (PTFE resin), and hexafluoropropylene resin (HFP resin).

[0036] The synthetic resin member 10 may also be a carbon fiber reinforced plastic (CFRTP) in which carbon fiber is blended with the above-mentioned synthetic resin, or a synthetic resin in which glass fiber, talc or other reinforcing materials, flame retardants, deterioration inhibitors, elastomer components, etc. are blended with the above-mentioned synthetic resin.

[0037] (3) Metallic parts 20 The metal member 20 is a member obtained by forming a metal into a predetermined shape such as a block, a plate, a wire, etc. The metal constituting the metal member 20 is not particularly limited, and various metals can be used.

[0038] For example, copper (Cu), iron (Fe), aluminum (Al), titanium (Ti), nickel (Ni), chromium (Cr), etc. can be used as the metal constituting the metal member 20. The metal member 20 may also be made of an alloy of two or more metals, such as a copper alloy, an iron alloy (steel material), an aluminum alloy, stainless steel, a titanium alloy, a nickel alloy, a chromium alloy, etc.

[0039] The shape of the metal member 20 can be any desired shape depending on the application, etc. Any method can be applied as a molding method for the metal member 20, and casting in which molten metal or the like is poured into a mold of a desired shape, cutting processing using a machine tool, etc., punching processing using a press machine, etc. may be used.

[0040] In order to improve the gas and liquid sealing performance (airtightness and liquidtightness) between the resin joining surface 12 and the metal joining surface 22 in the metal-resin joined body 30 and to improve the joining strength, it is necessary to bring the resin joining surface 12 into contact with the metal joining surface 22 without any gaps. In order to bring the resin joining surface 12 into contact with the metal joining surface 22 without any gaps, it is necessary to reduce the contact angle of the synthetic resin constituting the synthetic resin member 10 at the metal joining surface to improve wettability.

[0041] Therefore, the metal joining surface 22 of the metal member 20 of this embodiment is a surface that is spread and wetted by methylene iodide and pure water.

[0042] (4) Metal joint surface 22 The metal joining surface 22 comprises a concave roughened portion 23 and a peripheral portion 24 provided around the roughened portion 23, and the oxidation number of the metal constituting the metal member 20 differs between the roughened portion 23 and the peripheral portion 24, forming a surface that expands and wets with methylene iodide and pure water.

[0043] 1 and 2, the roughened portion 23 provided on the metal joining surface 22 has a groove shape extending in a predetermined direction (hereinafter, this direction may be referred to as a first direction X). A plurality of roughened portions 23 are provided on the metal joining surface 22 at intervals in a second direction Y perpendicular to the first direction X. Peripheral portions 24 are provided between adjacent roughened portions 23 in the second direction Y and on the outer sides of the roughened portions 23 in the second direction Y.

[0044] The roughened portion 23 is not limited to the linear grooves as shown in FIG. 2, but may be, for example, a circular groove extending in the circumferential direction, or a spiral groove that moves away from the center as it turns.

[0045] In metal member 20, the oxidation number of the metal in roughened portion 23 is different from the oxidation number of the metal in peripheral portion 24. In other words, the valence of the metal constituting metal member 20 is different between roughened portion 23 and peripheral portion 24, and the number of oxygen atoms bonded to one metal atom is different.

[0046] In this specification, whether or not the oxidation number of the metal in the roughened portion 23 is different from the oxidation number of the metal in the peripheral portion 24 is determined by X-ray photoelectron spectroscopy (XPS). That is, the ratio R of the metal oxide concentration to the metal concentration calculated from the peak area of ​​the spectrum corresponding to the metal and metal oxide measured by X-ray photoelectron spectroscopy is obtained for the roughened portion 23 and the peripheral portion 24. Then, if the ratio S (hereinafter, this ratio may be referred to as the difference rate S) obtained by dividing the difference ΔR between the ratio R in the roughened portion 23 and the ratio R in the peripheral portion 24 by the ratio R in the peripheral portion is 3% or more, it is determined that the oxidation number of the metal in the roughened portion 23 is different from the oxidation number of the metal in the peripheral portion 24.

[0047] In this embodiment, it is determined that the oxidation number of the metal in the roughened portion 23 is different from that in the peripheral portion 24 when the difference rate S is 3% or more, but the greater the difference rate S, the higher the wettability of the synthetic resin. In cases where high bonding strength or high sealing performance is required in the metal-resin bonded body 30, it may be determined that the oxidation number of the metal in the roughened portion 23 is different from that in the peripheral portion 24 when the difference rate S is 5% or more.

[0048] In such a metal joining surface 22, by changing the above-mentioned difference rate S or by changing the area of ​​the roughened portion 23 provided on the metal joining surface 22, the metal joining surface 22 can be made into a surface that is expanded and wetted by methylene iodide, or a surface that is expanded and wetted by pure water and methylene iodide.

[0049] In this specification, the term "spread wetting" refers to a state in which the contact angle of a liquid droplet on the metal joining surface 22 becomes 10° or less within one second after a liquid such as methylene iodide or pure water is dropped onto the metal joining surface 22.

[0050] It is preferable that the roughened portion 23 provided on the metal joining surface 22 (i.e., the inner wall surface of the groove that constitutes the roughened portion 23) satisfies at least one of (a) a fractal surface having a fractal dimension D of 2.1≦D≦3.0, (b) a surface having a kurtosis (sku) of 3 or more, and (c) a surface having a skewness of 0 or more.

[0051] The fractal dimension D was determined by the box counting method using cross-sectional SEM observation.

[0052] Kurtosis (sku) is a parameter that indicates the sharpness of the height distribution defined in ISO 25178, and is also called kurtosis. Kurtosis (sku) = 3 means that the height distribution is normal, kurtosis (sku) > 3 means that there are many sharp peaks and valleys on the surface, and kurtosis (sku) < 3 means that the surface is flat.

[0053] Skewness (ssk) is one of the three-dimensional surface texture parameters defined in ISO 25178, and is an index showing the degree of deviation of the height distribution from the average plane. When skewness (ssk) is 0, the surface shape is symmetrical with respect to the average plane, and when ssk exceeds 0, the surface shape is biased downward from the average plane, i.e., toward the lower side, and the area near the top of the convexities tends to become sharp and thin.

[0054] In addition, the roughened portion 23 is provided on a fractal surface that satisfies the above (a), and instead of or in addition to increasing the ratio α of the surface area of ​​the roughened portion 23 taking into account the fractal shape of the roughened portion 23 to the apparent area of ​​the roughened portion 23, the contact rate ζ in the roughened portion 23 can be reduced, thereby improving the wettability of the metal joining surface 22.

[0055] In other words, it is better to reduce the contact ratio ζ of the contact area when a rigid plate is placed on the metal joining surface 22 relative to the apparent area of ​​the roughened portion 23, and for example, a surface with a spire-like protrusion is excellent. The roughened portion 23 is preferably shaped to easily remove air from the metal joining surface 22 during joining, and for example, by providing the roughened portion 23 in the shape of a groove extending along the first direction X, the air from the metal joining surface 22 is discharged to the outside, and the roughened portion 23 is easily filled with synthetic resin.

[0056] (5) Method for manufacturing metal-resin bonded body 30 Next, a method for producing the metal-resin bonded body 30 will be described.

[0057] First, a synthetic resin member 10 and a metal member 20 molded into a predetermined shape are prepared. Then, a surface treatment step is performed to form a roughened portion 23 on the metal joining surface 22 of the metal member 20.

[0058] Thereafter, a joining process is performed in which the resin joining surface 12 of the synthetic resin member 10 is joined to the metal joining surface 22 that has been surface-treated to form the roughened portion 23. This results in a metal-resin joined body 30 in which the synthetic resin member 10 is joined to the metal joining surface 22 of the metal member 20. The surface treatment process and the joining process will be described in detail below.

[0059] (5-1) Surface treatment process In the surface treatment process, depending on the type of synthetic resin constituting the synthetic resin member 10, the metal joining surface 22 is surface treated so that methylene iodide will have an expanding wettability, or the metal joining surface 22 is surface treated so that pure water and methylene iodide will have an expanding wettability.

[0060] Specifically, when the synthetic resin constituting the synthetic resin member 10 satisfies the following formula (1), a first surface treatment is performed on the metal joining surface 22 so that methylene iodide can be spread wet. The first surface treatment is a surface treatment that forms a roughened portion 23 on the metal joining surface 22 and causes the oxidation number of the metal constituting the metal member 20 to differ between the roughened portion 23 and a peripheral portion 24.

[0061]

number

[0062] Furthermore, when the synthetic resin constituting the synthetic resin member 10 satisfies the following formula (2), a second surface treatment is performed on the metal joining surface 22 so that pure water and methylene iodide are spread wet. The second surface treatment is a surface treatment that forms a roughened portion 23 on the metal joining surface 22 and causes the oxidation number of the metal constituting the metal member 20 to differ between the roughened portion 23 and a peripheral portion 24.

[0063]

number

[0064] In this specification, the surface free energy and contact angle are values ​​measured according to a method in accordance with ISO19403. The OWRK method was adopted for polar component and component analysis of the surface free energy of solids, and the values ​​were obtained by measuring the contact angle using two reagents, pure water and methylene iodide. The surface free energy, f(γ p , γ d ) and g(γ p , γ d The values ​​of f(γ p , γ d ) and g(γ p , γ d ) indicates better extensibility.

[0065] [Table 1]

[0066] The first surface treatment and the second surface treatment are performed on the metal member 20 by irradiating it with laser light and exposing it to an atmosphere in which the oxygen concentration is controlled.

[0067] That is, first, a pulsed laser beam is irradiated onto the metal joining surface 22 while moving (scanning) the irradiation position of the laser beam in the first direction X. As a result, a roughened portion 23 extending in the first direction X is formed at the location irradiated with the laser beam, and a peripheral portion 24 is formed at the location around the roughened portion 23 that is not irradiated with the laser beam.

[0068] Then, the metal member 20 having the roughened surface portion 23 and the peripheral portion 24 formed thereon is exposed to an atmosphere with a controlled oxygen concentration, whereby the oxidation number of the metal in the roughened surface portion 23 and the peripheral portion 24 is made different.

[0069] In addition, by controlling at least one of the oxygen concentration of the atmosphere to which the metal member 20 is exposed and the time for which the metal member 20 is exposed to the atmosphere (for example, from one hour to one month), the oxidation number of the metal can be made different between the roughened portion 23 and the peripheral portion 24, and the difference rate S described later can be adjusted.

[0070] It is difficult to specify in general terms the laser light irradiation conditions performed in the first surface treatment and the second surface treatment because they differ depending on the metal constituting the metal member 20. As an example, however, when the metal member 20 is made of Al, the conditions are as follows.

[0071] That is, the laser used can be a pulsed laser that emits near-infrared light having a wavelength of 900 to 1100 nm, such as a YVO4 laser, a fiber laser, an excimer laser, or a disk laser. The laser conditions are that the spot interval M expressed by the following formula (7) is less than twice the laser spot radius R, and the laser light intensity U expressed by the following formula (8) is 1.0×105 W / mm 2 More than 1.0×109W / mm 2The metal bonding surface 32 is irradiated with a pulsed laser beam satisfying the following while being scanned in the second direction Y:

[0072] M=V / Q...Equation (7) U = E / (2πR 2 ×Q×B)...Equation (8) In equations (7) and (8), V represents the scanning speed of the laser light (mm / sec), Q represents the frequency of the laser light (Hz), E represents the laser power (W), R represents the spot radius of the laser light (mm), and B represents the pulse half-width of the laser light (sec).

[0073] As shown in FIG. 2, when multiple roughened portions 23 are formed at intervals in the second direction Y, the metal bonding surface 22 is irradiated with a similar pulsed laser light while scanning the same at positions spaced apart in the second direction Y at a predetermined interval in the first direction X.

[0074] In addition, by controlling the ratio of the roughened portion 23 in the metal bonding surface 22 and the exposure conditions to the oxygen atmosphere after the roughened portion 23 is formed by irradiating the metal bonding surface 22 with a laser beam, a first surface treatment in which methylene iodide is expanded to wet the metal, or a second surface treatment in which pure water and methylene iodide are expanded to wet the metal, can be performed. As an example of the conditions for exposing the metal member 20 to an atmosphere with a controlled oxygen concentration performed in the first surface treatment and the second surface treatment, in the first surface treatment, the metal member 20 is exposed to an atmosphere with an oxygen concentration of 15% by mass or more and 25% by mass or less and a temperature of 25° C. for one hour or more and within one week. In the second surface treatment, the metal member 20 is exposed to an atmosphere with an oxygen concentration of 0% by mass or more and 5% by mass or less and a temperature of 25° C. for one minute or more and within one week. In the second surface treatment, it is preferable to shorten the exposure time to the oxygen atmosphere or to expose the metal member 20 to an atmosphere with a lower oxygen concentration than in the first surface treatment.

[0075] In addition, in the first surface treatment and the second surface treatment, laser light is irradiated under the same conditions to form the roughened portion 23 and the peripheral portion 24, but it is preferable to increase the proportion of the roughened portion 23 in the metal joining surface 22 in the second surface treatment compared to the first surface treatment.

[0076] (5-2) Bonding process When the synthetic resin constituting the synthetic resin member 10 is a thermoplastic resin, in the joining step, for example, the metal member 20 and the synthetic resin member 10 are in a heated state and the resin joining surface 12 is brought into contact with the metal joining surface 22 while applying pressure. As a result, the synthetic resin member 10 is joined to the metal joining surface 22 of the metal member 20, and a metal resin joined body 30 is obtained. In this embodiment, the first and second steps are performed using a joining device 50 as shown in Fig. 3 to manufacture the metal resin joined body 30.

[0077] The joining device 50 includes a stage 51 on which the metal member 20 is placed, a heating device 52 that inductively heats the metal member 20 placed on the stage 51, a pressing device 53 that pressurizes and joins the synthetic resin member 10 to the metal member 20, and a control device 60 that controls the heating device 52 and the pressing device 53.

[0078] The heating device 52 is equipped with an induction heating coil connected to a power supply (not shown), and when driving power is input from the power supply device upon receiving a command from the control device 60, a magnetic field is generated from the induction heating coil to induction heat the metal joining surface 22 of the metal member 20 placed on the stage 51.

[0079] The heating device 52 includes a temperature sensor 56 that measures the temperature of the metal joining surface 22 of the metal member 20 placed on the stage 51. The temperature of the metal joining surface 22 detected by the temperature sensor 56 is input to the control device 60. The control device 60 controls the output of the heating device 52 based on the detected temperature input from the temperature sensor 56 so that the temperature of the metal joining surface 22 becomes a predetermined temperature.

[0080] In this embodiment, the temperature sensor 56 is a non-contact radiation thermometer, and measures the temperature of the induction heating coil of the heating device 52 at a portion close to the synthetic resin member 10. The correlation between the measured temperature and a thermocouple provided between the resin joining surface 12 and the metal joining surface 22 of the temperature sensor 56 has been previously examined. That is, with a thermocouple provided between the resin joining surface 12 and the metal joining surface 22, the metal joining surface 22 is heated by the heating device 52 while temperature is measured by the temperature sensor 56 and the thermocouple, and the correlation between the measured temperatures of the temperature sensor 56 and the thermocouple has been examined. The temperature of the thermocouple estimated from the measurement results based on the correlation with the thermocouple is regarded as the temperature of the metal joining surface 22.

[0081] The press device 53 includes a rod 54 formed of an insulator such as ceramics, a pressure applying section 55 that moves the rod 54 to press the synthetic resin member 10 against the metal member 20, and a pressure sensor 57 that detects the pressure acting on the synthetic resin member 10 when the rod 54 presses the synthetic resin member 10 against the metal member 20.

[0082] The rod 54 may be inserted into a hollow portion of an induction heating coil of the heating device 52 and disposed so as to face the synthetic resin member 10, as shown in FIG.

[0083] The pressurizing unit 55 includes a servo motor capable of variably controlling the pressurizing force, an air-pressure cylinder controlled by an electro-pneumatic regulator, a spring-type pressurizer, etc. Upon receiving a command from the control device 60, the pressurizing unit 55 can control the speed and position at which the synthetic resin member 10 is moved together with the rod 54, and the pressure at which the synthetic resin member 10 is pressed against the metal member 20.

[0084] The pressure sensor 57 detects the pressure acting on the synthetic resin member 10 when the synthetic resin member 10 comes into contact with the metal member 20 and presses the metal member 20, and inputs the detected pressure to the control device 60. Based on the detected pressure input from the pressure sensor 57, the control device 60 controls the output of the pressurizing unit 55 of the press device 53 so that the pressure acting on the synthetic resin member 10 becomes a predetermined pressure.

[0085] The control device 60 includes a computer, and is connected to the heating device 52 , the pressing device 53 , the temperature sensor 56 and the pressure sensor 57 .

[0086] The control device 60 controls the operation of the heating device 52 and the pressing device 53 in accordance with the detection results of the temperature sensor 56 and the pressure sensor 57 and a predetermined program, thereby joining the resin joining surface 12 to the metal joining surface 22 placed on the stage 51, thereby integrating the metal member 20 and the synthetic resin member 10.

[0087] Specifically, to manufacture the metal-resin joined body 30 using the joining apparatus 50, the metal member 20 is placed on the stage 51 so that the metal joining surface 22 that has been subjected to the first surface treatment or the second surface treatment faces the synthetic resin member 10 that will be set later.

[0088] Next, the resin joining surface 12 is placed opposite the metal joining surface 22 of the metal member 20 placed on the stage 51. In this embodiment, the synthetic resin member 10 is placed so that the resin joining surface 12 is in contact with the metal joining surface 22, as shown in FIG.

[0089] Next, the heating device 52 is disposed so as to face the metal joining surface 22 of the metal member 20 with the synthetic resin member 10 interposed therebetween. In the case shown in FIG. 3, the heating device 52 is disposed above the synthetic resin member 10, and the synthetic resin member 10 is disposed between the heating device 52 and the metal member 20.

[0090] Next, the metal joining surface 22 is heated to a first temperature T1 by the heating device 52, thereby heating the resin joining surface 12 in contact with the metal joining surface 22 to the first temperature T1, and a first process is performed in which the metal member 20 and the synthetic resin member 10 are pressurized with a first pressure P1 while heated to the first temperature T1.

[0091] Specifically, the control device 60 supplies a driving power source to the heating device 52, and generates a magnetic field from an induction heating coil provided in the heating device 52 to heat the metal joining surface 22 of the metal member 20. At that time, the driving power source supplied to the heating device 52 and the position of the induction heating coil provided in the heating device 52 are adjusted so that the temperature of the metal joining surface 22 detected by the temperature sensor 56 becomes the first temperature T1.

[0092] While the metal member 20 is heated as described above, the press device 53 moves the rod 54 to press the synthetic resin member 10 against the metal member 20, and pressurizes the synthetic resin member 10 and the metal member 20 so that the pressure detected by the pressure sensor 57 becomes the first pressure P1. As a result, the press device 53 brings the resin joint surface 12 into contact with the metal joint surface 22 heated to the first temperature T1, and presses the synthetic resin member 10 and the metal member 20 with the first pressure P1.

[0093] For example, the press device 53 presses the synthetic resin member 10 and the metal member 20 with a first pressure P1 for a predetermined time Sp1 (for example, 0.1 seconds or more and 10 seconds or less). While the press device 53 presses the synthetic resin member 10 and the metal member 20 with the first pressure P1, it is preferable that the heating device 52 continues to heat the metal member 20 so that the temperature of the metal joining surface 22 is maintained at the first temperature T1.

[0094] While the heating device 52 is heating the metal joining surface 22 to the first temperature T1, the pressing device 53 may pressurize the synthetic resin member 10 and the metal member 20 with a first pressure P1. For example, the temperature of the metal joining surface 22 is raised from room temperature to the first temperature T1 while being pressurized with the first pressure P1. Pressurizing the synthetic resin member 10 and the metal member 20 with the first pressure P1 while the temperature of the metal joining surface 22 is being raised makes it easier for heat to be transferred from the metal joining surface 22 to the resin joining surface 12, and the resin joining surface 12 can be quickly heated to the first temperature T1.

[0095] In addition, the press device 53 may not pressurize the synthetic resin member 10 and the metal member 20 until the temperature of the metal joining surface 22 reaches the first temperature T1, and then the press device 53 may press the synthetic resin member 10 and the metal member 20 with the first pressure P1 after the temperature of the metal joining surface 22 reaches the first temperature T1.

[0096] In this embodiment, when the synthetic resin constituting the synthetic resin member 10 satisfies the above formula (1), a first surface treatment is applied to the metal joining surface 22, and when the synthetic resin constituting the synthetic resin member 10 satisfies the above formula (2), a second surface treatment is applied to the metal joining surface 22.

[0097] Therefore, in the first step, when the synthetic resin of the synthetic resin member 10 near the resin joining surface 12 that comes into contact with the metal joining surface 22 melts or softens, the synthetic resin spreads over the metal joining surface 22 and fills the inside of the roughened portion 23 (see Figure 4).

[0098] When the roughened portion 23 of the metal joining surface 22 is formed with an uneven surface that satisfies the above (a) to (c), the synthetic resin that flows into the roughened portion 23 is likely to enter into the gaps in the uneven surface provided in the roughened portion 23.

[0099] Then, when the press device 53 presses the synthetic resin member 10 and the metal member 20 with the first pressure P1 for a predetermined time Sp1, the first step is completed and the process moves to the second step.

[0100] When the process proceeds to the second step, the heating device 52 stops or reduces the amount of heating of the metal member 20. In addition, the pressing device 53 pressurizes the synthetic resin member 10 and the metal member 20 so that the pressure detected by the pressure sensor 57 becomes a second pressure P2 higher than the first pressure P1.

[0101] In the second step, when the heating device 52 stops heating the metal member 20 or reduces the amount of heating, the first temperature T1 cannot be maintained at the metal joining surface 22, and the temperature drops from the first temperature T1. While the temperature of the metal joining surface 22 is dropping, the pressing device 53 presses the synthetic resin member 10 and the metal member 20 with a second pressure P2.

[0102] The press device 53 presses the synthetic resin member 10 and the metal member 20 at the second pressure P2 until the temperatures of the resin bonding surface 12 and the metal bonding surface 22 drop to at least the second temperature T2. Here, the second temperature T2 is a temperature lower than the first temperature T1. The press device 53 preferably continues to press the synthetic resin member 10 and the metal member 20 until the temperatures of the synthetic resin member 10 and the metal member 20 drop to a third temperature T3 lower than the second temperature T2.

[0103] Then, when the temperatures of the synthetic resin member 10 and the metal member 20 drop until they reach a predetermined temperature, the metal resin bonded body 30 in which the synthetic resin member 10 is bonded to the metal member 20 is taken out from the bonding device 50.

[0104] Here, the first temperature T1 can be equal to or higher than the melting point Tm of the thermoplastic resin constituting the synthetic resin member 10 and equal to or lower than the decomposition temperature of the thermoplastic resin (that is, equal to or lower than the temperature at which the thermoplastic resin starts to vaporize). Preferably, the first temperature T1 can be set to a temperature 20°C lower than the decomposition temperature of the thermoplastic resin or lower. More preferably, the first temperature T1 can be set to be equal to or higher than the melting point Tm of the thermoplastic resin constituting the synthetic resin member 10 and equal to or lower than a temperature 20°C higher than the melting point Tm of the thermoplastic resin (the first upper limit temperature) (Tm ≦ T1 ≦ Tm + 20°C).

[0105] The second temperature T2 may be a temperature lower than the first temperature T1, but it is preferably equal to or lower than a temperature 10°C higher than the melting point Tm of the thermoplastic resin constituting the synthetic resin member 10 (the second upper limit temperature) (T2 ≦ Tm + 10°C), and it is preferably set such that the second temperature T2 is equal to or higher than a temperature 20°C lower than the melting point Tm of the thermoplastic resin constituting the synthetic resin member 10 (the lower limit temperature). That is, it is preferably set such that the second temperature T2 is equal to or higher than the lower limit temperature and equal to or lower than the second upper limit temperature (Tm - 20°C ≦ T2 < Tm + 10°C).

[0106] The third temperature T3 may be a temperature at which the obtained metal resin bonded body 30 is easy to handle. For example, it can be set to be equal to or lower than either the glass transition point of the thermoplastic resin constituting the synthetic resin member 10 or 50°C.

[0107] In the first step, the first pressure P1 applied to the synthetic resin member 10 and the metal member 20 should be a pressure that provides sufficient contact for the heat of the heated metal member 20 to bring the synthetic resin member 10 to the same temperature as the metal member through thermal conduction, and is preferably a pressure equal to or lower than the compressive yield stress of the thermoplastic resin. This first pressure P1 varies depending on the thermoplastic resin that constitutes the synthetic resin member 10, so it is difficult to define it in general, but it is preferably equal to or lower than 10 MPa.

[0108] The second pressure P2 applied to the synthetic resin member 10 and the metal member 20 in the second step may be any pressure higher than the first pressure P1, and is preferably, for example, 10 MPa or more and 100 MPa or less.

[0109] When transitioning from the first process to the second process, the settings of either the heating device 52 or the pressing device 53 may be changed first and then the settings of the other device, or the settings of both may be changed simultaneously.

[0110] That is, when moving from the first step to the second step, the pressure applied by the press device 53 may be changed from the first pressure P1 to the second pressure P2 after the heating by the heating device 52 is stopped or the amount of heating is reduced, or the heating by the heating device 52 may be stopped or the amount of heating is reduced and the pressure applied by the press device 53 may be changed simultaneously. Also, the heating by the heating device 52 may be stopped or the amount of heating may be reduced immediately after the pressure applied by the press device 53 is changed.

[0111] In addition, in this embodiment, the case where the press device 53 moves the synthetic resin member 10 toward the metal member 20 has been described, but the metal member 20 may be moved toward the synthetic resin member 10.

[0112] In addition, the synthetic resin member 10 and the metal member 20 may be joined locally, or may be joined over a wide area. The planar shape of the joining portion may be any shape, such as a point, a line, or a surface.

[0113] Furthermore, in this embodiment, when transitioning from the first process to the second process, the pressure applied by the press device 53 is changed from the first pressure P1 to the second pressure P2 without taking into consideration the temperature of the metal joining surface 22. However, after the first process is performed, the pressure applied to the metal member 20 and the synthetic resin member 10 may be changed from the first pressure P1 to the second pressure P2 after the temperature of the metal joining surface 22 has dropped to the second temperature T2.

[0114] That is, after the first step is performed for a predetermined time Sp1 in the same manner as above, first, the heating by the heating device 52 is stopped or the amount of heating is reduced. Then, the temperatures of the resin joining surface 12 and the metal joining surface 22 are lowered (cooled) until they reach a second temperature T2 lower than the first temperature T1. When the temperatures of the resin joining surface 12 and the metal joining surface 22 reach the second temperature T2, the pressing device 53 changes the pressure applied to the synthetic resin member 10 and the metal member 20 from the first pressure P1 to the second pressure P2, and the second step is started.

[0115] With this joining method, the pressure applied by the press device 53 can be changed at an appropriate timing so that the synthetic resin member 10 is not excessively deformed, and a metal-resin joined body 30 with high joining strength can be obtained while suppressing deformation of the synthetic resin member 10.

[0116] (6) Effects A synthetic resin satisfying the above formula (1) exhibits high wettability to a metal joining surface 22 that is expanded and wetted by methylene iodide. Therefore, by joining a synthetic resin member 10 having such a synthetic resin on its resin joining surface 12 to a metal joining surface 22 of a metal member 20, the synthetic resin spreads on the metal joining surface 22 without applying high pressure, even at a relatively low temperature near the melting point of the synthetic resin during joining, and the synthetic resin fills the roughened portion 23 provided on the metal joining surface 22 without any gaps. As a result, the synthetic resin member 10 and the metal member 20 can be firmly joined while obtaining airtightness and liquid tightness between them.

[0117] A synthetic resin satisfying the above formula (2) exhibits high wettability to the metal joining surface 22, which is expanded and wetted by pure water and methylene iodide. Therefore, by joining a synthetic resin member 10 having such a synthetic resin on the resin joining surface 12 to the metal joining surface 22 of a metal member 20, the synthetic resin spreads on the metal joining surface 22 without applying high pressure, even at a relatively low temperature near the melting point of the synthetic resin during joining, and the synthetic resin fills the roughened portion 23 provided on the metal joining surface 22 without any gaps. As a result, the synthetic resin member 10 and the metal member 20 can be firmly joined while maintaining airtightness between them.

[0118] In this embodiment, when the fractal dimension D obtained by the box counting method through cross-sectional SEM observation of the roughened portion 23 is 2.1 or more and 3.0 or less, the roughened portion 23 becomes a fractal surface with large surface roughness, and the synthetic resin exhibits high wettability to the metal joining surface 22, so that the synthetic resin constituting the synthetic resin member 10 is likely to spread over the metal joining surface 22 during joining.

[0119] Furthermore, when the roughened portion 23 has a kurtosis (sku) of 3 or more, or a skewness of 0 or more, the synthetic resin exhibits high wettability with respect to the metal joining surface 22, so that the synthetic resin constituting the synthetic resin member 10 easily spreads over the metal joining surface 22 during joining.

[0120] In this embodiment, if the roughened portion 23 provided on the metal joining surface 22 is in the form of a concave groove extending in a predetermined direction, when the synthetic resin member 10 and the metal member 20 are joined, the air present in the roughened portion 23 is pushed out along the groove, making it easier for the synthetic resin to fill the roughened portion 23 without any gaps.

[0121] (7) Examples In order to specifically demonstrate the effects of the above-described embodiment, metal members (test pieces) were produced in Examples 1 to 8 and Comparative Examples 1 to 3. Note that the present invention is not limited to Examples 1 to 8.

[0122] In Examples 1 to 8 and Comparative Examples 1 and 2, a roughened portion having a length of 18 mm in the first direction and a pitch of 0.1 mm in the second direction was formed on the metal joining surface of the metal member by irradiating a single mode laser having a laser wavelength of 1064 nm and a spot radius of 0.03 mm. The metals used in Examples 1 to 4 and Comparative Examples 1 and 2 are as shown in Table 1 below.

[0123] In Examples 1, 3, 5, and 7, a roughened portion was formed on the metal bonding surface, and then the metal bonding surface was left for 24 hours in an atmosphere at 25° C. with an oxygen concentration of 0.5% by mass and a balance of nitrogen, while in Examples 2, 4, 6, and 8, a roughened portion was formed on the metal bonding surface, and then the metal bonding surface was left for 24 hours in an atmosphere at 25° C. with an oxygen concentration of 20% by mass and a balance of nitrogen. In Comparative Examples 1 to 3, after the roughened portion was formed on the metal bonding surface, oxides attached to the metal bonding surface were removed with acid, and the metal bonding surface was left for one week in an atmosphere at 25° C. with an oxygen concentration of 20% by mass and a balance of nitrogen, so that a uniform oxide film was formed on the metal bonding surface, and the oxidation number of the metal on the metal bonding surface was made constant.

[0124] Then, synthetic resin members made of PA66 resin, PPS resin, PBT resin and PP resin were joined to the metal joining surfaces of the metal members of Examples 1 to 4 and Comparative Examples 1 and 2 to prepare test pieces (metal-resin joined bodies) for the joint strength test. Synthetic resin members made of PA66 resin and PPS resin were joined to the metal joining surfaces of the metal members of Examples 5 to 8 and Comparative Example 3 to prepare test pieces (metal-resin joined bodies) for the joint strength test. The dimensions of the metal members were 18 mm x 45 mm x 1.6 mm, the dimensions of the synthetic resin members were 10 mm x 40 mm x 3.0 mm, and the dimensions of the joint between the metal members and the synthetic resin members were 10 mm x 5 mm.

[0125] In addition, a through hole having a diameter of 20 mm was provided through the metal bonding surface of the metal members of Examples 1, 2, and 4 and Comparative Examples 1 and 2, and PA66 resin and PPS resin were bonded to the metal bonding surface so as to block the through hole, thereby preparing test pieces for helium (He) leak tests.

[0126] Details of the metal members, details of the synthetic resin members, dimensions of the metal members, dimensions of the synthetic resin members, and bonding areas (overlap areas) between the synthetic resin members and the metal members used in Examples 1 to 8 and Comparative Examples 1 to 3 are as follows. ·Cu:C1100 Aluminum: A1050 ·SUS304 Fe: SPCC PA66 resin: Asahi Kasei Leona 66 (1300S) PPS resin: Susteel (registered trademark) SGX120 PBT resin: Toray Trecon (110G-X54) PP resin: Novatec (registered trademark) HG30U The evaluation method is as follows.

[0127] (A) SEM observation of metal bonding surface For the metal members of Examples 1 to 8 and Comparative Examples 1 to 3, SEM observation was performed on the metal joining surfaces on which roughened portions were formed and the cross sections of the metal members without joining the synthetic resin members. Figures 5 and 6 show a plan view and a cross section of the metal member of Example 2, and in Figure 5, the symbol X indicates the first direction (the direction in which the laser light was scanned), and the symbol Y indicates the second direction.

[0128] 5 and 6, a groove-like rough surface portion extending in the first direction X was formed at the location irradiated with the laser, and a peripheral portion not irradiated with the laser was formed around the rough surface portion. A fractal surface was formed inside the rough surface portion, with a fractal dimension of 2.35 determined by the box counting method.

[0129] In Examples 1, 3 to 8 and Comparative Examples 1 to 3, the same roughened portion as in Example 2 was formed on the metal joining surface.

[0130] (B) Difference rate S Using an XPS measurement device (PHI5000VersaProbeII manufactured by ULVAC-PHI, Inc.), the roughened portions and peripheral portions of Examples 1 to 4 and Comparative Examples 1 and 2 were measured under the following conditions. Note that the diameter of the measurement range is preferably set to be smaller than the width (the length in the second direction Y) of the roughened portion 23 and the peripheral portion 24, and is preferably set to be 1 / 2 or less of the width of the roughened portion 23 and the peripheral portion 24.

[0131] <XPS Measurement Conditions> X-ray conditions: Al alpha mono 4.5W Measurement range: φ18μm In Examples 1 and 2 and Comparative Example 1, the 2p3 / 2 spectrum of Cu derived from the roughened portion and the peripheral portion was acquired. After separating the peaks corresponding to Cu and Cu2O and the peak corresponding to CuO from the acquired spectrum, the peak area of each peak was calculated. Then, for each of the roughened portion and the peripheral portion, the ratio R (= S2 / S1) of the peak area S2 of the peak corresponding to CuO to the peak area S1 of the peak corresponding to Cu and Cu2O was calculated, and the ratio R in the roughened portion and the ratio R in the peripheral portion were obtained. Then, the difference ΔR between the ratio R in the roughened portion and the ratio R in the peripheral portion was divided by the ratio R in the peripheral portion to obtain the difference rate S.

[0132] In Examples 3 and 4 and Comparative Example 2, the 2p spectrum of Al derived from the roughened portion and the peripheral portion was acquired. After separating the peak corresponding to Al and the peak corresponding to Al2O3 from the acquired spectrum, the peak area of each peak was calculated. Then, for each of the roughened portion and the peripheral portion, the ratio R (= S4 / S3) of the peak area S4 of the peak corresponding to Al2O3 to the peak area S3 of the peak corresponding to Al was calculated, and the ratio R in the roughened portion and the ratio R in the peripheral portion were obtained. Then, the difference ΔR between the ratio R in the roughened portion 23 and the ratio R in the peripheral portion 24 was divided by the ratio R in the peripheral portion to obtain the difference rate S.

[0133] In Examples 1 to 4 and Comparative Examples 1 and 2, spectra were acquired from four locations each of the roughened portion and the peripheral portion, and the average value of the difference rate S calculated from the acquired spectra was taken as the difference rate S of each test piece.

[0134] (C) Wettability of metal bonding surfaces It was confirmed whether methylene iodide and pure water could spread and wet the metal joining surfaces of the metal members of Examples 1 to 8 and Comparative Examples 1 to 3.

[0135] Using a Kyowa Interface Science Co., Ltd. DMs-401, methylene iodide and pure water were dropped onto the metal joint surface of each test piece. If the contact angle of the droplet on the metal joint surface was 10° or less one second after that, it was considered to be extensional wetting, and if the contact angle was greater than 10°, it was considered to be adhesion wetting.

[0136] (D) Bond strength test The bonding strength was measured for the test pieces for the bonding strength test in Examples 1 to 8 and Comparative Examples 1 to 3. In the test method specified in JIS K 6850, the dimensions of the synthetic resin member, the dimensions of the metal member, and the bonding area between the synthetic resin member and the metal member were changed as described above, and other conditions were in accordance with the same standard, and measurements were performed using a tensile tester (Shimadzu Corporation, Autograph AGX-V) at a tensile speed of 10 mm / min and a measurement temperature of 25° C. Four test pieces were prepared for each of Examples 1 and 2 and Comparative Example 1, and the average value of the four measured values ​​was taken as the respective bonding strengths.

[0137] (E) Helium leak test For the test pieces for the He leak test of Examples 1 to 2 and 4 and Comparative Examples 1 and 2, He was pressurized to 1.5 atmospheres and the airtightness between the metal bonding surface and the resin bonding surface was evaluated by the vacuum hood method specified in JIS Z 2331. The smaller the value, the higher the vacuum that can be maintained and the higher the airtightness.

[0138] [Table 2]

[0139] The results are shown in Table 2. In Comparative Examples 1 and 2 in which the difference rate S was less than 3%, methylene iodide and pure water showed adhesion wetting.

[0140] On the other hand, in Examples 1 to 8 in which the difference rate S was 3% or more, methylene iodide exhibited spreading wetting. In Examples 1, 3, 5, and 7, pure water as well as methylene iodide exhibited spreading wetting.

[0141] The test pieces of Examples 1 and 3, in which methylene iodide and pure water are spread wet, and the test pieces of Examples 2 and 4, in which methylene iodide is spread wet and pure water is adhesive wet, were bonded with PA66 resin, PPS resin, PBT resin, and PP resin with higher bonding strength than those of Comparative Examples 1 and 2. Moreover, the test pieces of Examples 5 and 7, in which methylene iodide and pure water are spread wet, and the test pieces of Examples 6 and 8, in which methylene iodide is spread wet and pure water is adhesive wet, were bonded with PA66 resin and PPS resin with higher bonding strength than those of Comparative Examples 1 to 3.

[0142] Furthermore, the test pieces of Examples 1, 2 and 4, compared with Comparative Examples 1 and 2, had higher airtightness at the bonded surfaces with the PA66 resin and the PPS resin.

[0143] In particular, the test pieces of Examples 1, 3, 5, and 7, in which methylene iodide and pure water exhibited expansion wettability, were bonded with high bonding strength to the PA66 resin satisfying the above formula (2), compared to the test pieces of Examples 2, 4, 6, and 8, in which methylene iodide exhibited expansion wettability and pure water exhibited adhesion wettability.

[0144] Furthermore, the test piece of Example 1 had higher airtightness at the joint surface with the PA66 resin, which satisfied the above formula (2), as compared with the test piece of Example 2. [Explanation of symbols]

[0145] 10...synthetic resin member, 12...resin joining surface, 20...metal member, 22...metal joining surface, 23...roughened portion, 24...periphery, 50...joining device, 51...stage, 52...heating device, 53...pressing device, 54...rod, 55...pressurizing portion, 56...temperature sensor, 57...pressure sensor, 60...control device

Claims

1. A metal member made of copper or aluminum is joined to a resin joining surface of a resin member having a synthetic resin that satisfies the following formula (1): a metal joining surface in contact with the resin joining surface, The metal joining surface comprises a roughened portion having a recess and a peripheral portion provided around the roughened portion, and the oxidation number of the metal constituting the metal member is different between the roughened portion and the peripheral portion, so that methylene iodide exhibits expansion wetting. [0010] In formula (1), γ iod p is the polar component of the surface free energy of methylene iodide (mJ / m 2 ) γ iod ｄ is the dispersive component of the surface free energy of methylene iodide (mJ / m 2 ), γ p is the polar component of the surface free energy of the synthetic resin in the solid state (mJ / m 2 ), γ ｄ is the dispersion component of the surface free energy of the synthetic resin in the solid state (mJ / m 2 ), γ is the sum of the polar component and the dispersive component of the surface free energy of the synthetic resin in a solid state (=γ p +γ ｄ ).

2. In a metal member made of copper that is joined to a resin joining surface of a resin member having a synthetic resin that satisfies the following formula (2), a metal joining surface in contact with the resin joining surface, The metal joining surface comprises a roughened portion having a recess and a peripheral portion provided around the roughened portion, and the oxidation number of the metal constituting the metal member is different between the roughened portion and the peripheral portion, and pure water and methylene iodide are allowed to expand and wet the metal member. [0025] In formula (2), γ w p is the polar component of the surface free energy of pure water (mJ / m 2 ) γ iod ｄ is the dispersive component of the surface free energy of methylene iodide (mJ / m 2 ), γ p is the polar component of the surface free energy of the synthetic resin in the solid state (mJ / m 2 ), γ ｄ is the dispersion component of the surface free energy of the synthetic resin in the solid state (mJ / m 2 ), γ is the sum of the polar component and the dispersive component of the surface free energy of the synthetic resin in a solid state (=γ p +γ ｄ ).

3. 3. The metal member according to claim 1, wherein the roughened portion has a fractal dimension of 2.1 or more and 3.0 or less, the fractal dimension being determined by a box counting method through cross-sectional SEM observation of the roughened portion.

4. The metal member according to claim 1 or 2, wherein the roughened portion is provided in the form of a groove extending in a predetermined direction.

5. A metal-resin bonded body in which a metal bonding surface of a metal member made of copper or aluminum is brought into contact with a resin bonding surface of a resin member having a synthetic resin that satisfies the following formula (3), thereby bonding the metal member and the resin member together: The metal resin joint body has a roughened portion having a recess and a peripheral portion provided around the roughened portion, and the oxidation number of the metal constituting the metal member is different between the roughened portion and the peripheral portion, and methylene iodide exhibits expansion wetting. [0030] In formula (3), γ iod p is the polar component of the surface free energy of methylene iodide (mJ / m 2 ) γ iod ｄ is the dispersive component of the surface free energy of methylene iodide (mJ / m 2 ), γ p is the polar component of the surface free energy of the synthetic resin in the solid state (mJ / m 2 ), γ ｄ is the dispersion component of the surface free energy of the synthetic resin in the solid state (mJ / m 2), γ is the sum of the polar component and the dispersive component of the surface free energy of the synthetic resin in a solid state (=γ p +γ ｄ ).

6. A metal-resin bonded body in which a metal bonding surface of a metal member made of copper is brought into contact with a resin bonding surface of a resin member having a synthetic resin that satisfies the following formula (4), thereby bonding the metal member and the resin member, The metal resin joint body has a roughened portion having a recess and a peripheral portion provided around the roughened portion, and the oxidation number of the metal constituting the metal member is different between the roughened portion and the peripheral portion, and pure water and methylene iodide are expanded to wet the metal resin joint body. [0045] In formula (4), γ w p is the polar component of the surface free energy of pure water (mJ / m 2 ) γ iod ｄ is the dispersive component of the surface free energy of methylene iodide (mJ / m 2 ), γ p is the polar component of the surface free energy of the synthetic resin in the solid state (mJ / m 2 ), γ ｄ is the dispersion component of the surface free energy of the synthetic resin in the solid state (mJ / m 2 ), γ is the sum of the polar component and the dispersive component of the surface free energy of the synthetic resin in a solid state (=γ p +γ ｄ ).

7. A method for producing a metal-resin bonded body in which a metal bonding surface of a metal member made of copper or aluminum is brought into contact with a resin bonding surface of a resin member having a synthetic resin that satisfies the following formula (5), thereby bonding the metal member and the resin member together, A method for manufacturing a metal-resin bonded body, comprising the steps of: forming a roughened portion having a recess on the metal bonding surface; and forming a peripheral portion around the roughened portion; and making the oxidation number of the metal constituting the metal member different between the roughened portion and the peripheral portion, thereby performing a process for expanding and wetting methylene iodide to the metal bonding surface. [0050] In formula (5), γ iod p is the polar component of the surface free energy of methylene iodide (mJ / m 2 ) γ iod ｄ is the dispersive component of the surface free energy of methylene iodide (mJ / m 2 ), γ p is the polar component of the surface free energy of the synthetic resin in the solid state (mJ / m 2 ), γ ｄ is the dispersion component of the surface free energy of the synthetic resin in the solid state (mJ / m 2 ), γ is the sum of the polar component and the dispersive component of the surface free energy of the synthetic resin in a solid state (=γ p +γ ｄ ).

8. A method for producing a metal-resin bonded body in which a metal bonding surface of a metal member made of copper is brought into contact with a resin bonding surface of a resin member having a synthetic resin that satisfies the following formula (6), thereby bonding the metal member and the resin member together, A method for manufacturing a metal-resin bonded body, comprising the steps of: forming a roughened portion having a recess on the metal bonding surface; and forming a peripheral portion around the roughened portion; and making the oxidation number of the metal constituting the metal member different between the roughened portion and the peripheral portion, thereby performing a process for expanding wettability of the metal bonding surface with pure water and methylene iodide. [006] In formula (6), γ w p is the polar component of the surface free energy of pure water (mJ / m 2 ) γ iod ｄ is the dispersive component of the surface free energy of methylene iodide (mJ / m 2 ), γ p is the polar component of the surface free energy of the synthetic resin in the solid state (mJ / m 2 ), γ ｄ is the dispersion component of the surface free energy of the synthetic resin in the solid state (mJ / m 2 ), γ is the sum of the polar component and the dispersive component of the surface free energy of the synthetic resin in a solid state (=γ p+γ ｄ ).