Production method for metal / resin joined body

Abstract

The present invention makes it possible to obtain a metal / resin joined body having high bonding strength while retaining the shape of a synthetic resin member that has been pre-molded into a predetermined shape.　This method for producing a metal / resin joined body 30, in which a metal member 20 and a synthetic resin member 10 are joined, includes: a first step of bringing a metal joining surface 22, which has been heated to a first temperature T1, into contact with a resin joining surface 12 and applying a first pressure P1 to the metal member 20 and the synthetic resin member 10; and a second step of applying a second pressure P2, which is higher than the first pressure P1, to the metal member 20 and the synthetic resin member 10 at a second temperature T2, which is lower than the first temperature T1.

Description

Method for manufacturing metal-resin bonded body

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

[0002] A metal-resin joined body is known in which a metal member made of metal and a synthetic resin member made of synthetic resin are joined (see, for example, Patent Document 1 below). When joining the metal member to the synthetic resin member, the synthetic resin member and the metal member are joined by applying pressure to each other in a heated state.

[0003] In addition, in a metal-resin bonded body, in order to increase the bonding strength between the metal member and the synthetic resin member, a roughened portion (anchor portion) may be formed on the surface of the metal member (metal bonding surface) to which the synthetic resin member is bonded by laser irradiation or chemical etching. When producing such a metal-resin bonded body, in order to fill the interior of the roughened portion formed on the metal bonding surface with resin, the resin material constituting the synthetic resin member is heated and melted, and the synthetic resin member and the metal member are pressurized to bring the melted resin material into contact with the metal bonding surface of the metal member.

[0004] Patent No. 5998303

[0005] However, in conventional manufacturing methods in which a synthetic resin member and a metal member are joined by applying pressure under heating, when joining a synthetic resin member that has been pre-formed into a predetermined shape to a metal member, it is difficult to firmly join the metal member and the synthetic resin member while maintaining the shape of the synthetic resin member.

[0006] The present invention has been made in consideration of the above points, and has an object to provide a method for manufacturing a metal-resin joined body that can firmly join a synthetic resin member to a metal member made of a metal material while maintaining the shape of the synthetic resin member that has been molded into a predetermined shape in advance.

[0007] According to this embodiment, the following aspects [1] to [7] are provided.

[0008] [1] A method for manufacturing a metal-resin bonded body in which a metal joining surface of a metal member is brought into contact with a resin joining surface of a resin member molded into a predetermined shape, thereby joining the metal member and the resin member, the method comprising: a first step of bringing the resin joining surface into contact 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 pressurizing 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.

[0009] [2] The method for manufacturing a metal resin joined body according to the above [1], wherein, after the first step is performed, 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 performed.

[0010] [3] The method for manufacturing a metal resin joined body according to the above-mentioned [1], wherein, after the first step, the temperature of the metal joining surfaces is lowered to the second temperature, and then the pressure applied to the metal member and the resin member is changed from the first pressure to the second pressure, and the second step is performed.

[0011] [4] The method for producing a metal resin bonded body according to any one of [1] to [3] above, wherein the first temperature is a temperature equal to or higher than the melting point of the resin material constituting the resin member.

[0012] [5] The method for producing a metal resin bonded body according to the above [4], 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.

[0013] [6] The method for producing a metal resin bonded body according to the above [3], wherein the second temperature is equal to or lower than a temperature that is 10° C. higher than the melting point of the resin material that constitutes the resin member.

[0014] [7] The method for producing a metal resin joined body according to the above-mentioned [6], 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.

[0015] According to the above-described method for producing a metal-resin bonded body, the bond strength between the metal member and the synthetic resin member can be improved while maintaining the shape of the synthetic resin member that has been molded into a predetermined shape in advance.

[0016] FIG. 1 is a cross-sectional view of a metal-resin bonded body manufactured by a method for manufacturing a metal-resin bonded body according to one embodiment of the present invention; FIG. 2 is a view showing a first step of a method for manufacturing a metal-resin bonded body according to one embodiment of the present invention;

[0017] Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the drawings, the sizes of components may be exaggerated for the purpose of explanation. The present invention is not limited to the following embodiments. The following embodiments are presented as examples and are not intended to limit the scope of the invention. The novel embodiments can be implemented in various other forms, and various omissions, substitutions, and modifications can be made without departing from the spirit of the invention.

[0018] (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 a thermoplastic synthetic resin and a metal member 20 made of a metal.

[0019] 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 formed 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.

[0020] (2) Synthetic Resin Member 10 The synthetic resin member 10 is a member obtained by molding a thermoplastic resin into a predetermined shape such as a block, plate, or line by a known method such as injection molding, extrusion molding, or compression molding.

[0021] Specific examples of thermoplastic synthetic resins that constitute the synthetic resin member 10 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 66 (PA66), epoxy resin, liquid crystal polymer (LCP resin), modified polyphenylene ether resin (modified PPE), reactor-type soft polypropylene resin (metallocene-based reactor-type TPO resin), Examples of such resins 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).

[0022] The synthetic resin member 10 may also be a carbon fiber reinforced thermoplastic resin (CFRTP) in which carbon fiber is blended into the above-mentioned thermoplastic resin, or a thermoplastic resin in which a reinforcing material such as glass fiber or talc, a flame retardant, an anti-degradation agent, an elastomer component, or the like is blended into the above-mentioned thermoplastic resin.

[0023] (3) Metal Member 20 The metal member 20 is a member formed by molding 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.

[0024] 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. Furthermore, the metal member 20 may 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, or a chromium alloy.

[0025] The shape of the metal member 20 can be any desired shape depending on the application, etc. Any method can be applied as a method for forming the metal member 20, and may include casting in which molten metal or the like is poured into a mold of a desired shape, cutting using a machine tool, or punching using a press machine, etc.

[0026] Before performing the first and second steps described below, the metal member 20 may be subjected to a roughening treatment to provide an unevenly roughened portion on the metal joining surface 22. Various methods can be used for the roughening treatment. For example, the roughened portion may be formed on the metal joining surface 22 by laser light irradiation, chemical etching, or press working.

[0027] (4) Manufacturing Method of Metal-Resin Joined Body 30 The metal-resin joined body 30 is obtained by performing the first and second steps on the synthetic resin member 10 described in (2) above and the metal member 20 described in (3) above. In this embodiment, the first and second steps are performed using a joining device 50 as shown in FIG. 2 to manufacture the metal-resin joined body 30.

[0028] 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 press 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 press device 53.

[0029] The heating device 52 is equipped with an induction heating coil connected to a power supply (not shown), and when a driving power supply is input from the power supply in response to 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.

[0030] The heating device 52 is equipped with 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.

[0031] In this embodiment, the temperature sensor 56 is a non-contact radiation thermometer that measures the temperature of a portion of the induction heating coil of the heating device 52 that is close to the synthetic resin member 10. The correlation between the measured temperature of this temperature sensor 56 and a thermocouple provided between the resin joining surface 12 and the metal joining surface 22 has been investigated in advance. That is, with a thermocouple provided between the resin joining surface 12 and the metal joining surface 22, temperature measurements are performed by the temperature sensor 56 and the thermocouple while the heating device 52 is heating the metal joining surface 22, and the correlation between the measured temperatures of the temperature sensor 56 and the thermocouple has been investigated. The temperature of the thermocouple estimated from the measurement results based on the correlation with the thermocouple is used as the temperature of the metal joining surface 22.

[0032] The press device 53 includes a rod 54 formed of an insulating material such as ceramic, 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.

[0033] As shown in FIG. 2, the rod 54 may be inserted into the hollow portion of the induction heating coil of the heating device 52 and disposed so as to face the synthetic resin member 10 .

[0034] The pressure applying unit 55 includes a servo motor that can variably control the pressure, an air cylinder controlled by an electro-pneumatic regulator, a spring pressure device, etc. Upon receiving a command from the control device 60, the pressure applying 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.

[0035] The pressure sensor 57 detects the pressure acting on the synthetic resin member 10 when the synthetic resin member 10 abuts against 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.

[0036] 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 .

[0037] The control device 60 controls the operation of the heating device 52 and the pressing device 53 according to 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 and integrating the metal member 20 and the synthetic resin member 10.

[0038] Specifically, to manufacture the metal-resin bonded body 30 using the bonding device 50, the metal member 20 is placed on the stage 51 so that the metal bonding surface 22 faces the synthetic resin member 10 that will be set later.

[0039] In addition, when roughening the metal joining surface 22 of the metal member 20 by a roughening treatment or forming an oxide film on the metal joining surface 22 by a thermal oxidation treatment or the like, the roughening treatment or thermal oxidation treatment may be performed before placing the metal member 20 on the stage 51, and the metal member 20 may be positioned so that the treated surface faces the synthetic resin member 10 that will be set later.

[0040] Next, the resin joining surface 12 is placed opposite the metal joining surface 22 of the metal member 20 placed on the stage 51. As shown in FIG. 2 , 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.

[0041] 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. 2 , 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.

[0042] 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 step 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.

[0043] 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 this time, the control device 60 adjusts the driving power source supplied to the heating device 52, the position of the induction heating coil provided in the heating device 52, and the like, so that the temperature of the metal joining surface 22 detected by the temperature sensor 56 becomes the first temperature T1.

[0044] 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 applies pressure to 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 joining surface 12 into contact with the metal joining surface 22 heated to the first temperature T1, and applies pressure to the synthetic resin member 10 and the metal member 20 with the first pressure P1.

[0045] For example, the press device 53 applies a first pressure P1 to the synthetic resin member 10 and the metal member 20 for a predetermined time Sp1 (e.g., 0.1 seconds or more and 10 seconds or less). While the press device 53 applies the first pressure P1 to the synthetic resin member 10 and the metal member 20, the heating device 52 preferably continues to heat the metal member 20 so that the temperature of the metal joining surface 22 is maintained at the first temperature T1.

[0046] While the heating device 52 is heating the metal joining surface 22 to the first temperature T1, the press device 53 may pressurize the synthetic resin member 10 and the metal member 20 with the 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 facilitates heat transfer 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.

[0047] 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 pressurize 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.

[0048] 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.

[0049] When the process moves to the second step, the heating device 52 stops or reduces the amount of heating of the metal member 20. The pressing device 53 presses 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 that is higher than the first pressure P1.

[0050] 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 press device 53 presses the synthetic resin member 10 and the metal member 20 with a second pressure P2.

[0051] The press device 53 applies a second pressure P2 to the synthetic resin member 10 and the metal member 20 until the temperatures of the resin joining surface 12 and the metal joining surface 22 drop to at least a second temperature T2. Here, the second temperature T2 is a temperature lower than the first temperature T1. It is preferable that the press device 53 continue to apply pressure to 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 that is lower than the second temperature T2.

[0052] Then, when the temperatures of the synthetic resin member 10 and the metal member 20 are lowered to a predetermined temperature, the metal-resin bonded body 30 in which the synthetic resin member 10 is bonded to the metal member 20 is removed from the bonding device 50 .

[0053] Here, the first temperature T1 can be set to a temperature 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 (i.e., equal to or lower than the temperature at which the thermoplastic resin begins to vaporize). Preferably, the first temperature T1 can be set to a temperature equal to or lower than a temperature 20°C lower than the decomposition temperature of the thermoplastic resin. More preferably, the first temperature T1 can be set to a temperature 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 (first upper limit temperature) 20°C higher than the melting point Tm of the thermoplastic resin (Tm≦T1≦Tm+20°C).

[0054] The second temperature T2 may be any temperature lower than the first temperature T1, but is preferably equal to or lower than a temperature (second upper limit temperature) that is 10°C higher than the melting point Tm of the thermoplastic resin that constitutes the synthetic resin member 10 (T2≦Tm+10°C), and it is preferable to set the second temperature T2 to a temperature (lower limit temperature) that is 20°C lower than the melting point Tm of the thermoplastic resin that constitutes the synthetic resin member 10. In other words, it is preferable to set the second temperature T2 to a temperature that 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).

[0055] The third temperature T3 may be any temperature that allows easy handling of the resulting metal-resin bonded body 30, and may be, for example, equal to or lower than the glass transition point of the thermoplastic resin constituting the synthetic resin member 10 or 50°C. In the first step, the first pressure P1 applied to the synthetic resin member 10 and the metal member 20 may be any pressure that ensures sufficient contact so that the heat of the heated metal member 20 can heat the synthetic resin member 10 to the same temperature as the metal member through thermal conduction, and is preferably equal to or lower than the compressive yield stress of the thermoplastic resin. Because this first pressure P1 varies depending on the thermoplastic resin constituting the synthetic resin member 10, it is difficult to define a specific value, but it is preferably equal to or lower than 10 MPa.

[0056] 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.

[0057] 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 may be changed, or both settings may be changed simultaneously.

[0058] That is, when transitioning from the first step to the second step, the heating by the heating device 52 may be stopped or the amount of heating may be reduced, and then the pressure applied by the pressing device 53 may be changed from the first pressure P1 to the second pressure P2, or the heating by the heating device 52 may be stopped or the amount of heating may be reduced and the pressure applied by the pressing 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 pressing device 53 is changed.

[0059] Furthermore, 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 .

[0060] 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.

[0061] (5) Effect When the metal joining surface 22 heated to the high first temperature T1 is brought into contact with the resin joining surface 12, if the synthetic resin member 10 and the metal member 20 are pressed with high pressure, the heated synthetic resin member 10 is likely to be significantly deformed by the heat from the metal member 20. However, when joining the synthetic resin member 10 to the metal member 20, it is preferable to heat the synthetic resin member 10 and the metal member 20 while applying pressure, so that the resin joining surface 12 of the synthetic resin member 10 is uniformly heated by the heat from the metal member 20.

[0062] In this embodiment, in the first step, the synthetic resin member 10 and the metal member 20 are pressurized with a first pressure P1 that is weaker than the second pressure P2, thereby suppressing deformation of the synthetic resin member 10 and facilitating uniform transfer of heat from the metal member 20 to the resin joining surface 12 from the metal joining surface 22. As a result, the thermoplastic resin that constitutes the resin joining surface 12 spreads uniformly over the metal joining surface 22 and easily adheres to it. Furthermore, even if a roughened portion is formed on the metal joining surface 22, applying pressure with the weak first pressure P1 makes it easier for the thermoplastic resin that constitutes the resin joining surface 12 to fill the interior of the roughened portion.

[0063] In addition, since the resin density of the thermoplastic resin that makes up the synthetic resin member 10 decreases as the temperature increases, the resin density of the synthetic resin member 10 that receives heat from the metal member 20 when joining the metal member 20 and the synthetic resin member 10 is likely to decrease near the resin joining surface 12.

[0064] In this embodiment, in the second step performed after the first step, the synthetic resin member 10 and the metal member 20 are pressurized at a second temperature T2 lower than the first temperature T1 and a second pressure P2 higher than the first pressure P1, thereby making it possible to increase the resin density near the resin joining surface 12 while suppressing undesired deformation of the synthetic resin member 10 molded into a predetermined shape.

[0065] That is, in this embodiment, the first step uniformly heats the resin joining surface 12 that contacts the metal joining surface 22 while suppressing deformation of the synthetic resin member 10, thereby causing the thermoplastic resin that constitutes the resin joining surface 12 to adhere uniformly to the metal joining surface 22. Then, the second step increases the pressure to further improve the adhesion of the thermoplastic resin to the metal joining surface 22, while increasing the resin density of the synthetic resin member 10 near the resin joining surface 12, thereby making it possible to obtain a metal-resin joined body 30 with high joining strength.

[0066] In this embodiment, if the first temperature T1 is equal to or higher than the melting point Tm of the thermoplastic resin that constitutes the synthetic resin member 10, the fluidity of the thermoplastic resin near the resin joining surface 12 increases during the first step, further improving the adhesion of the resin joining surface 12 to the metal joining surface 22. Furthermore, by setting the first temperature T1 to an upper limit temperature that is 20°C higher than the melting point Tm of the thermoplastic resin that constitutes the synthetic resin member 10, it is possible to suppress thermal decomposition of the resin material that constitutes the synthetic resin member 10 and undesired deformation of the synthetic resin member 10 that occurs when the metal member 20 and the synthetic resin member 10 are pressed together with the first pressure P1 in the first step.

[0067] In this embodiment, when the second temperature T2 is a temperature below the melting point Tm of the thermoplastic resin that constitutes the synthetic resin member 10, the synthetic resin member 10 is less likely to deform into an undesired shape even when the synthetic resin member 10 is pressed together with the metal member 20 with the second pressure P2 in the second step. Furthermore, by setting the second temperature T2 to a temperature equal to or higher than the lower limit temperature that is 20° C. lower than the melting point Tm of the thermoplastic resin that constitutes the synthetic resin member 10, the resin density near the resin joining surface 12 can be effectively increased in the second step.

[0068] (6) Modifications A modification of the above embodiment will be described. In the above 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.

[0069] In this modified example, after the first step is performed for a predetermined time Sp1, similar to the above-described embodiment, the heating device 52 stops heating or reduces the amount of heating. Then, the temperatures of the resin joining surfaces 12 and the metal joining surfaces 22 are lowered (cooled) to a second temperature T2 that is lower than the first temperature T1. When the temperatures of the resin joining surfaces 12 and the metal joining surfaces 22 reach the second temperature T2, the press 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.

[0070] The press device 53 continues to pressurize 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 from the second temperature T2 to the third temperature T3.

[0071] Then, when the temperatures of the synthetic resin member 10 and the metal member 20 are lowered to a predetermined temperature, the metal-resin bonded body 30 in which the synthetic resin member 10 is bonded to the metal member 20 is removed from the bonding device 50 .

[0072] Here, the first temperature T1 can be set to a temperature 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 (i.e., equal to or lower than the temperature at which the thermoplastic resin begins to vaporize). Preferably, the first temperature T1 can be set to a temperature 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 (upper limit temperature) that is 20°C higher than the melting point Tm of the thermoplastic resin (i.e., Tm ≤ T1 ≤ Tm + 20°C).

[0073] Furthermore, the second temperature T2 may be any temperature lower than the first temperature T1, but is preferably a temperature lower than the melting point Tm of the thermoplastic resin that constitutes the synthetic resin member 10, and it is preferable to set the second temperature T2 to a temperature (lower limit temperature) that is 20°C lower than the melting point Tm of the thermoplastic resin that constitutes the synthetic resin member 10 (i.e., Tm-20°C≦T2<Tm).

[0074] In this modified example, the temperature of the resin joining surface 12 and the metal joining surface 22 is lowered to the second temperature T2, and then the pressure applied by the press device 53 is changed from the first pressure P1 to the second pressure P2.Therefore, the pressure applied by the press device 53 can be changed at an appropriate timing so that the synthetic resin member 10 does not deform excessively, and a metal-resin joined body 30 with high joining strength can be obtained while suppressing deformation of the synthetic resin member 10.

[0075] (7) Examples In order to specifically demonstrate the effects of the above-described embodiments, metal-resin joined bodies (test specimens) were produced in Examples 1 and 2 and Comparative Examples 1 to 4. Note that the present invention is not limited to Examples 1 and 2.

[0076] In Examples 1 and 2, the first step was performed by heating the metal joining surfaces to a first temperature T1 using the heating device 52 and then pressing the synthetic resin member and the metal member with a first pressure P1 for one second using the pressing device 53. Thereafter, heating by the heating device 52 was stopped, and the pressing force by the pressing device 53 was changed from the first pressure P1 to a second pressure P2, to perform the second step. The synthetic resin member 10 and the metal member 20 were pressed with the second pressure P2 by the pressing device 53 until the temperatures of the synthetic resin member 10 and the metal member 20 reached a third temperature T3, thereby producing the metal-resin joined bodies of Examples 1 and 2. Note that in the second step, heating by the heating device 52 was stopped and the pressing force of the pressing device 53 was changed simultaneously.

[0077] In Comparative Examples 1 to 4, after the first step was performed, the pressure applied by the press device 53 was not changed and heating by the heater 52 was stopped to produce a metal-resin bonded body.

[0078] Specifically, in Comparative Examples 1 to 4, the heating device 52 heated the metal joining surface 22 to a first temperature T1, and the press device 53 pressed the synthetic resin member 10 and the metal member 20 at a first pressure P1 for one second to perform the first step. Thereafter, while maintaining the pressure applied to the synthetic resin member 10 and the metal member 20 by the press device 53 at the first pressure P1, heating by the heating device 52 was stopped, and the press device 53 pressed the synthetic resin member 10 and the metal member 20 at the first pressure P1 until the temperatures of the synthetic resin member 10 and the metal member 20 reached a third temperature T3, thereby producing metal-resin joined bodies of Modified Examples 1 to 4.

[0079] In Examples 1 and 2 and Comparative Examples 1 to 4, synthetic resin members made of PPS resin and metal members made of SUS304 with the metal joining surface roughened by laser irradiation were used. Details of the synthetic resin members, details of the metal members, and the joining areas (overlap areas) between the synthetic resin members and the metal members are as follows:

[0080] The first temperature T1, third temperature T3, first pressure P1, and second pressure P2 for Examples 1 and 2 and Comparative Examples 1 to 4 are as shown in Table 1.

[0081] Synthetic resin member Type of thermoplastic resin: PPS resin (FZ-2100 manufactured by DIC Corporation, melting point: 280°C) Size (length x width x thickness): 10 mm x 50 mm x 3 mm Metal member Type of metal: SUS304 Size (length x width x thickness): 18 mm x 40 mm x 1.5 mm Bonding area between synthetic resin member and metal member: 5 x 10 mm The evaluation method is as follows.

[0082] (a) Bonding strength 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 taken 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 Examples 1 to 4, and the average value of the four measured values ​​was used as the respective bonding strengths.

[0083] (b) Amount of compressive deformation The thickness of the synthetic resin member of the obtained metal-resin bonded body was measured, and the amount of change from the thickness (3 mm) of the synthetic resin member before bonding was calculated. Four test pieces were prepared for each of Examples 1 and 2 and Comparative Examples 1 to 4, and the average of the four changes was used as the amount of compressive deformation for each test piece.

[0084] The results are shown in Table 1. In Example 1, high bonding strength was obtained while significantly reducing the compressive change of the synthetic resin members compared to Comparative Example 1. In Example 2, while maintaining the same level of bonding strength as Comparative Examples 1 and 2, it was possible to significantly reduce the compressive change of the synthetic resin members compared to Comparative Examples 1 and 2.

[0085] In Comparative Example 3, the amount of compressive deformation could be kept small, but practical bonding strength was not obtained. In Comparative Example 4, the synthetic resin member was not bonded to the metal member.

[0086] 10...synthetic resin member, 12...resin joining surface, 20...metal member, 22...metal joining surface, 30...metal-resin joined body, 50...joining device, 51...stage, 52...heating device, 53...pressing device, 54...rod, 55...pressurizing section, 56...temperature sensor, 57...pressure sensor, 60...control device

Claims

1. In a method for manufacturing a metal-resin bonded body by bringing a metal bonding surface of a metal member into contact with a resin bonding surface of a resin member formed into a predetermined shape to bond the metal member and the resin member, a first step of bringing the resin bonding surface into contact with the metal bonding surface heated to a first temperature and pressing the metal member and the resin member at a first pressure; a second step of pressing the metal member and the resin member at a second pressure higher than the first pressure at a second temperature lower than the first temperature of the metal bonding surface; A method for manufacturing a metal-resin bonded body comprising the steps of:

2. When the first step is executed, the heating of the metal bonding surface is stopped or the heating amount is reduced, and the pressure for pressing the metal member and the resin member is changed from the first pressure to the second pressure to execute the second step. The method for manufacturing a metal-resin bonded body according to claim 1.

3. When the first step is executed, after the temperature of the metal bonding surface is lowered to the second temperature, the pressure for pressing the metal member and the resin member is changed from the first pressure to the second pressure to execute the second step. The method for manufacturing a metal-resin bonded body according to claim 1.

4. The first temperature is a temperature equal to or higher than the melting point of the resin material constituting the resin member. The method for manufacturing a metal-resin bonded body according to any one of claims 1 to 3.

5. 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 20 ° C higher than the melting point of the resin material. The method for manufacturing a metal-resin bonded body according to claim 4.

6. 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. The method for manufacturing a metal-resin bonded body according to claim 3.

7. 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 20 ° C higher than the melting point of the resin material, The second temperature is equal to or lower than a temperature 10 ° C higher than the melting point of the resin material and equal to or higher than a lower limit temperature 20 ° C lower than the melting point of the resin material. The method for manufacturing a metal-resin bonded body according to claim 6.

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