阅读说明：本技术 金属树脂接合体的制造方法 (Method for producing metal-resin bonded body ) 是由 斋圣一 于 2020-03-06 设计创作，主要内容包括：本发明的金属树脂接合体30的制造方法在将包含热塑性树脂的合成树脂部件10和包含金属的金属部件20接合得到的金属树脂接合体30的制造方法的基础上,具有以下工序：第一工序,在该工序中,将成型为规定形状的合成树脂部件10的表面12暴露于加热到所述热塑性树脂的施加1.8MPa载荷时的载荷下挠曲温度Tf以上的第一温度T1的空气中；以及第二工序,在该工序中,将合成树脂部件10的表面12和金属部件20的表面22接合。由此,能够提高金属部件20与合成树脂部件10的接合强度。(The method for producing a metal-resin bonded body 30 according to the present invention is a method for producing a metal-resin bonded body 30 obtained by bonding a synthetic resin member 10 containing a thermoplastic resin and a metal member 20 containing a metal, and further comprises the steps of: a first step of exposing a surface 12 of a synthetic resin member 10 molded into a predetermined shape to air heated to a first temperature T1 equal to or higher than a deflection temperature Tf under a load of the thermoplastic resin when a load of 1.8MPa is applied; and a second step of bonding the surface 12 of the synthetic resin member 10 and the surface 22 of the metal member 20. This can improve the bonding strength between the metal member 20 and the synthetic resin member 10.)

1. A method for producing a metal-resin bonded body obtained by bonding a synthetic resin member containing a thermoplastic resin and a metal member containing a metal,

the method for producing a metal-resin bonded body is characterized by comprising the following steps:

a first step of exposing a surface of the synthetic resin member molded into a predetermined shape to a gas heated to a first temperature, the first temperature being a temperature equal to or higher than a deflection temperature of the thermoplastic resin under a load of 1.8 MPa; and

and a second step of bonding the surface of the synthetic resin member and the surface of the metal member.

2. The method of manufacturing a metal-resin bonded body according to claim 1,

in the second step, the surface of the synthetic resin member and the surface of the metal member are joined at a second temperature lower than the first temperature.

3. The method of manufacturing a metal-resin bonded body according to claim 1 or 2,

the second temperature is a temperature lower than the melting point of the thermoplastic resin.

4. The method of manufacturing a metal-resin bonded body according to any one of claims 1 to 3,

in the first step, the metal member is heated in a gas in a state where the metal member and the synthetic resin member are arranged to face each other with a space therebetween, and thereby the gas between the metal member and the synthetic resin member is heated to the first temperature by heat of the metal member.

5. The method of manufacturing a metal-resin bonded body according to claim 4,

in the first step, the metal member is heated by induction heating.

6. The method of manufacturing a metal-resin bonded body according to any one of claims 1 to 5,

in the second step, the surface of the synthetic resin member and the surface of the metal member are heated at a second temperature lower than the first temperature, and one of the metal member and the synthetic resin member is pressed against the other at a pressure equal to or higher than the compressive yield stress of the thermoplastic resin, thereby joining the metal member and the synthetic resin member.

7. The method of manufacturing a metal-resin bonded body according to any one of claims 1 to 6,

in the first step, the gas exposed on the surface of the synthetic resin member is an oxygen-containing gas.

8. The method of manufacturing a metal-resin bonded body according to any one of claims 1 to 7,

comprising: a third step of forming an oxide film on the surface of the metal member,

in the second step, the oxide film is disposed between the metal member and the synthetic resin member to join the metal member and the synthetic resin member.

9. The method of manufacturing a metal-resin bonded body according to claim 8,

in the third step, the temperature rise per 1 minute when the surface of the metal member is heated is equal to or higher than the melting point temperature of the metal.

10. The method of manufacturing a metal-resin bonded body according to any one of claims 1 to 9,

comprising: a fourth step of roughening the surface of the metal member,

in the second step, the roughened surface of the metal member and the synthetic resin member are joined.

Technical Field

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

Background

As a method for producing a metal-resin joined body by joining a metal member containing a metal and a synthetic resin member containing a synthetic resin, various methods have been proposed (for example, see patent documents 1 and 2 below).

It proposes that: the bonding strength between the metal member and the synthetic resin member is improved by forming an anchor portion having a concavo-convex shape on the surface of the metal member by laser or chemical etching. In the method of providing the metal with the anchor portion by providing the unevenness thereto, the joint is likely to be broken due to the difference in the linear expansion coefficient between the resin and the metal when the thermal shock test is performed. In addition, in order to obtain a strong joint, complicated anchor holes are required, but it is difficult to form the anchor holes, and it is difficult to fill the inside of the anchor holes with resin completely, and it is difficult to obtain a stable joint strength.

In the case of joining a metal member and a synthetic resin member by intermolecular force due to dipole interaction of the metal and the resin, such as friction joining, it is difficult to directly bond a resin having small dipole interaction to the metal, such as an olefin-based resin such as polypropylene resin (PP resin). The bonding strength can be improved by adding a compound having a high dipole interaction such as carboxylic anhydride to the resin having a small dipole interaction, but physical properties such as strength of the synthetic resin member itself may be deteriorated.

Documents of the prior art

Patent document

Patent document 1: japanese patent laid-open publication No. 2018-8409

Patent document 2: japanese patent laid-open No. 2012 and 170975

Disclosure of Invention

The present invention has been made in view of the above circumstances, and an object thereof is to provide a method for producing a metal-resin bonded body capable of improving the bonding strength between a metal member containing a metal and a synthetic resin member containing a thermoplastic resin material.

According to the present embodiment, the following aspects [1] to [10] are provided.

[1] A method for producing a metal-resin bonded body obtained by bonding a synthetic resin member containing a thermoplastic resin and a metal member containing a metal, the method comprising: a first step of exposing a surface of the synthetic resin member molded into a predetermined shape to a gas heated to a first temperature, the first temperature being a temperature equal to or higher than a deflection temperature of the thermoplastic resin under a load of 1.8 MPa; and a second step of bonding the surface of the synthetic resin member and the surface of the metal member.

[2] The method of manufacturing a metal-resin bonded body according to the above [1], wherein in the second step, the surface of the synthetic resin member and the surface of the metal member are bonded at a second temperature lower than the first temperature.

[3] The method of producing a metal-resin bonded body according to the above [1] or [2], wherein the second temperature is a temperature lower than a melting point of the thermoplastic resin.

[4] The method of manufacturing a metal-resin bonded body according to any one of [1] to [3], wherein in the first step, the metal member is heated in a gas in a state where the metal member and the synthetic resin member are arranged to face each other with a space therebetween, and thereby the gas between the metal member and the synthetic resin member is heated to the first temperature by heat of the metal member.

[5] The method of producing a metal-resin bonded body according to the above [4], wherein in the first step, the metal member is heated by induction heating.

[6] The method of manufacturing a metal-resin bonded body according to any one of [1] to [5], wherein in the second step, the surface of the synthetic resin member and the surface of the metal member are heated at a second temperature lower than the first temperature, and one of the metal member and the synthetic resin member is pressed against the other at a pressure equal to or higher than a compressive yield stress of the thermoplastic resin, thereby bonding the metal member and the synthetic resin member.

[7] The method of producing a metal-resin bonded body according to any one of the above [1] to [6], wherein in the first step, the gas exposed to the surface of the synthetic resin member is an oxygen-containing gas.

[8] The method of producing a metal-resin bonded body according to any one of [1] to [7], comprising: and a third step of forming an oxide film on a surface of the metal member, wherein in the second step, the oxide film is disposed between the metal member and the synthetic resin member to join the metal member and the synthetic resin member.

[9] The method of producing a metal-resin bonded body according to [8], wherein in the third step, an increase temperature per 1 minute when the surface of the metal member is heated is equal to or higher than a melting point temperature of the metal.

[10] The method of producing a metal-resin bonded body according to any one of [1] to [9], comprising: and a fourth step of roughening the surface of the metal member, wherein in the second step, the roughened surface of the metal member and the synthetic resin member are joined.

Effects of the invention

In the present invention, a metal-resin bonded body having high bonding strength between a metal member and a synthetic resin member is obtained.

Drawings

Fig. 1 is a sectional view of a metal-resin bonded body produced by a method for producing a metal-resin bonded body according to an embodiment of the present invention.

Fig. 2 is a view showing a first step of the method for producing a metal-resin bonded body according to an embodiment of the present invention.

Fig. 3 is a diagram showing a second step of the method for producing a metal-resin bonded body according to the embodiment of the present invention.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings. 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 new embodiment can be implemented in other various forms, and various omissions, substitutions, and changes can be made without departing from the spirit of the invention.

(1) Metal-resin bonded body 30

First, a metal-resin bonded body 30 produced by the production method of the present embodiment will be described. As shown in fig. 1, the metal-resin bonded body 30 includes: a synthetic resin member 10 made of a thermoplastic resin and a metal member 20 made of a metal are obtained by joining a surface 12 of the synthetic resin member 10 (hereinafter, this surface may be referred to as a "resin joint surface") and a surface 22 of the metal member 20 (hereinafter, this surface may be referred to as a "metal joint surface").

(2) Synthetic resin member 10

The synthetic resin member 10 is: the thermoplastic resin is molded into a predetermined shape such as a block shape, a plate shape, or a linear shape. The synthetic resin member 10 may be a coating film of a thermoplastic resin or an adhesive layer containing an adhesive made of a thermoplastic resin. Specific examples of the thermoplastic resin constituting the synthetic resin member 10 include: polypropylene resins (PP resins), polyacetal resins (POM resins), polyphenylene sulfide resins (PPs resins), polyether ether ketone resins (PEEK), acrylonitrile/butadiene/styrene resins (ABS resins), polyethylene resins (PE resins), polybutylene terephthalate resins (PBT resins), polyamide resins (PA resins) such as nylon 66(PA66), epoxy resins, liquid crystal polymers (LCP resins), modified polyphenylene ether resins (modified PPEs), and reactive soft polypropylene resins (metallocene reactive TPO resins). The synthetic resin member 10 may be a carbon fiber reinforced thermoplastic resin (CFRTP) obtained by blending carbon fibers with the above-described thermoplastic resin, or a synthetic resin obtained by blending a reinforcing material such as glass fibers or talc, a flame retardant material, a deterioration preventing agent, an elastomer component, or the like with the above-described thermoplastic resin.

(3) Metal part 20

The metal member 20 is: a member obtained by molding a metal into a predetermined shape such as a block shape, a plate shape, or a wire shape. The metal constituting the metal member 20 is not particularly limited, and various metals can be used. For example, as the metal constituting the metal member 20, there can be used: copper (Cu), iron (Fe), aluminum (Al), titanium (Ti), nickel (Ni), chromium (Cr), and the like. The metal member 20 may be made of an alloy containing 2 or more metals, such as a copper alloy, an iron alloy (iron steel), an aluminum alloy, stainless steel, a titanium alloy, a nickel alloy, and a chromium alloy.

The shape of the metal member 20 may be set to a desired shape according to the application and the like. Any method may be applied to the molding method of the metal member 20, and: casting in which a molten metal or the like is poured into a mold having a desired shape, cutting by a machine tool or the like, and pressing by a press machine or the like.

In addition, the metal member 20 may have an oxide film (metal oxide) formed on the metal bonding surface 22. The oxide film may be a natural oxide film naturally formed on the surface of the metal. The oxide film may be a film formed on the surface of the metal member 20 by a surface treatment with an oxidizing agent, an electrolytic treatment with anodic oxidation, a plasma oxidation treatment, a heat oxidation treatment in an oxygen-containing gas, or the like.

Preferably, the oxide film is formed on the surface of the metal member 20 by rapidly heating the surface of the metal member 20 in an atmosphere of an oxygen-containing gas such as air. The temperature of the surface of the metal member 20 rising every 1 minute at the rapid heating is preferably not lower than the melting point temperature of the metal constituting the metal member 20. By rapidly heating the surface of the metal member 20 in this manner, a dense oxide film can be formed on the surface of the metal member 20. Then, by rapidly heating the surface of the metal member 20, microcracks are generated on the surface of the oxide film, and the bonding area with the synthetic resin member 10 increases.

The surface of the metal member 20 can be rapidly heated by various methods such as laser heating, induction heating, or resistance heating, but it is preferable to form an oxide film by heating the surface of the metal member 20 by laser irradiation in view of a high temperature rise rate at the time of heating and easy temperature control.

In addition, the metal member 20 may be subjected to roughening treatment for providing a concave-convex shape on the metal bonding surface 22. The roughening treatment may be performed by various methods. For example, the metal joint surface 22 may be roughened by laser irradiation, chemical etching, or press working.

Preferably, the surface of the metal member 20 is rapidly heated in an atmosphere containing oxygen to form an oxide film on the surface of the metal member 20, and the metal joint surface 22 is roughened by forming micro cracks on the surface of the oxide film.

(4) Method for manufacturing metal-resin bonded body 30

The metal-resin bonded body 30 is obtained by performing the first step and the second step on the synthetic resin member 10 described in the above (2) and the metal member 20 described in the above (3), thereby obtaining the metal-resin bonded body 30. In the present embodiment, the metal-resin bonded body 30 is manufactured by performing the first step and the second step using the bonding apparatus 50 shown in fig. 2 and 3.

The bonding apparatus 50 includes: a table 51 on which the metal member 20 is placed; a heating device 52 for induction-heating the metal member 20 placed on the table 51; and a pressing device 53 that press-bonds the synthetic resin member 10 to the metal member 20.

The heating device 52 includes an induction heating coil connected to a power supply device (not shown), and when a driving power is input from the power supply device, the induction heating coil generates a magnetic field to inductively heat the metal bonding surface 22 of the metal member 20 placed on the table 51.

The pressing device 53 includes: a rod 54 formed of an insulator such as ceramic; and a pressing part 55 for pressing the synthetic resin member 10 against the metal member 20 by moving the rod 54. As shown in fig. 2, the rod 54 may be inserted into a hollow portion of an induction heating coil provided in the heating device 52 and disposed to face the synthetic resin member 10. The pressurization unit 55 includes: the speed at which the synthetic resin member 10 moves together with the rod 54 and the pressure at which the synthetic resin member 10 is pressed against the metal member 20 can be controlled by a pneumatic cylinder or a spring-type pressurizer controlled by an electro-pneumatic regulator.

In order to produce the metal-resin bonded body 30 using the bonding apparatus 50, first, the metal member 20 is placed on the table 51 in an atmosphere in which a gas is present so that the metal bonding surface 22 faces the synthetic resin member 10 provided thereafter. When an oxide film is formed on the surface of the metal member 20 by a heat oxidation treatment or the like, or when the surface of the metal member 20 is roughened by a roughening treatment, the metal member 20 is disposed so that the formed oxide film or roughened surface faces the synthetic resin member 10 provided later.

Next, the synthetic resin member 10 is disposed so that the resin bonding surface 12 faces the metal bonding surface 22 of the metal member 20 placed on the table 51 with a space therebetween. The distance between the metal bonding surface 22 of the metal member 20 and the resin bonding surface 12 of the synthetic resin member 10 is set to 0.001mm to 10mm, for example.

Next, the heating device 52 is disposed so as to face the metal joint surface 22 of the metal member 20 with the synthetic resin member 10 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.

Next, a first step of exposing the resin bonding surface 12 of the synthetic resin member 10 to a gas heated to the first temperature T1 is performed.

Specifically, a driving power source is supplied to the heating device 52, and a magnetic field is generated by an induction heating coil provided in the heating device 52 to heat the metal bonding surface 22 of the metal member 20. At this time, the driving power supplied to the heating device 52, the position of the induction heating coil provided in the heating device 52, and the like are adjusted so that the metal bonding surface 22 of the metal member 20 reaches the first temperature T1.

With the heating of the metal member 20 as described above, the gas between the metal member 20 and the synthetic resin member 10 is heated to the first temperature T1. Thus, the resin joint surface 12 of the synthetic resin member 10 facing the metal joint surface 22 of the metal member 20 is exposed to the gas heated to the first temperature T1, and the resin joint surface 12 of the synthetic resin member 10 reaches the first temperature T1. The heating device 52 heats the metal bonding surface 22 of the metal member 20 for a predetermined time S1 (e.g., 1 to 10 seconds) to perform the first step, and then the first step is terminated to proceed to the second step.

After the first step is completed, the second step is continued, and therefore, the heating device 52 stops or reduces the heating amount of the metal member 20, and lowers the temperature (cools) until the temperature of the resin bonding surface 12, the metal bonding surface 22, and the surroundings thereof (the gas between the metal member 20 and the synthetic resin member 10) reaches the second temperature T2. Then, the synthetic resin member 10 and the metal member 20 are joined at a second temperature T2.

That is, in the second step, the pressing device 53 moves the synthetic resin member 10 at a predetermined speed V to collide against the metal member 20 at a temperature lower than the first temperature T1 (second temperature T2). At this time, the position of the synthetic resin member 10 corresponding to the tip of the rod 54 is pressed strongly against the metal member 20, and is pressed against the metal member 20 at a predetermined pressure P for a predetermined time S2. Thus, the metal-resin bonded body 30 in which the resin bonded surface 12 of the synthetic resin member 10 and the metal bonded surface 22 of the metal member 20 are partially bonded (spot-bonded) is obtained. Then, the second step is ended.

Here, the first temperature T1 is: a temperature of a deflection temperature Tf under a load of 1.8MPa or more of the thermoplastic resin constituting the synthetic resin member 10. When the synthetic resin member 10 is formed of a thermoplastic resin containing a reinforcing material such as carbon fiber, glass fiber, or talc, the deflection temperature under load Tf when a load of 1.8MPa is applied to the thermoplastic resin constituting the synthetic resin member 10 is: deflection temperature under load Tf of a thermoplastic resin without a reinforcing material under a load of 1.8 MPa.

The upper limit of the first temperature T1 may be equal to or lower than the decomposition temperature of the thermoplastic resin constituting the synthetic resin member 10, i.e., a temperature lower than the temperature at which the thermoplastic resin starts to vaporize. For example, the upper limit of the first temperature T1 may be set to 1000 ℃. Preferably, the upper limit value of the first temperature T1 may be set to a temperature 20 ℃ higher than the melting point Tm of the thermoplastic resin constituting the synthetic resin member 10.

The second temperature T2 may be lower than the first temperature T1, and is preferably equal to or higher than the deflection temperature Tf under load when a load of 1.8MPa is applied to the thermoplastic resin constituting the synthetic resin member 10. The second temperature T2 is preferably a temperature lower than the melting point Tm of the thermoplastic resin constituting the synthetic resin member 10. The temperature difference between the first temperature T1 and the second temperature T2 is preferably 1 ℃ to 20 ℃.

In the present specification, the melting point Tm of the thermoplastic resin is: a value measured at a temperature rise rate of 10 ℃ per minute using a differential scanning calorimeter in accordance with JIS K7121. The melting points of the representative thermoplastic resins are 168 ℃ for the polypropylene resin, 265 ℃ for the nylon 66, 232-267 ℃ for the polybutylene terephthalate resin, and 280 ℃ for the polyphenylene sulfide resin.

In addition, the deflection temperature under load Tf of the thermoplastic resin is: the deflection temperature under load when a load of 1.8MPa was applied was measured by the method according to JIS K7191. The deflection temperature Tf under a load when a load of 1.8MPa is applied to a representative thermoplastic resin is 57 to 65 ℃ for a polypropylene resin, 66 to 68 ℃ for a nylon 66, 58 ℃ for a polybutylene terephthalate resin, and 105 ℃ for a polyphenylene sulfide resin.

The first step is preferably performed in an oxygen-containing gas such as air. That is, it is preferable to heat the metal bonding surface 22 and the resin bonding surface 12 to the first temperature T1 in the atmosphere of the oxygen-containing gas, and expose the metal bonding surface 22 and the resin bonding surface 12 to the oxygen-containing gas heated to the first temperature T1.

If the first step is performed in an atmosphere containing oxygen, the resin bonding surface 12 of the synthetic resin member 10 reacts with oxygen contained in the oxygen-containing gas, and thus a functional group capable of undergoing a neutralization reaction with a basic or amphoteric oxide to be chemically bonded is generated on the resin bonding surface 12 of the synthetic resin member 10.

Generally, since the surface of the metal member 20 is oxidized and covered with an oxide film containing a metal oxide, the functional group generated on the resin bonding surface 12 is bonded to the metal oxide present on the metal bonding surface 22 of the metal member 20 by van der waals force or hydrogen bonding. Further, when the synthetic resin member 10 and the metal member 20 are bonded under heat and pressure, the functional group of the resin bonding surface 12 and the metal oxide of the metal member 20 undergo a neutralization reaction (dehydration condensation) to form a covalent bond.

Examples of the functional group formed on the resin bonding surface 12 include at least one of a carboxyl group (-COOH), a carbonyl group (-CO-), and a hydroxyl group (-OH) formed by oxidative decomposition of a thermoplastic resin constituting the synthetic resin member 10. When the thermoplastic resin constituting the synthetic resin member 10 is a resin containing a sulfur atom (heteroatom) such as polyphenylene sulfide resin (PPS), the functional group included in the resin bonding surface 12 may include, in addition to a carboxyl group, a carbonyl group, and a hydroxyl group: sulfo (-SO)₃H) Sulfonyl (-SO)₂-, a sulfanyl group (-SH), a disulfide group (-SS-), and the like.

As an example of the neutralization reaction occurring by the joining of the metal member 20 and the synthetic resin member 10, when the resin joining surface 12 has a carboxyl group (R — COOH) as a functional group and the metal member 20 is made of a 2-valent metal, the neutralization reaction as shown in the following formula (1) occurs.

2(R－COOH)+MeO＝2(R－COO)－Me+H₂O↑···(1)

In formula (1), R is the main chain of the thermoplastic resin constituting the synthetic resin member 10, and Me is the metal constituting the metal member 20.

In addition, when the first step is performed in an atmosphere containing oxygen, the second temperature T2 is preferably: a temperature at which a functional group of the resin bonding surface 12 of the synthetic resin member 10 and a metal oxide formed on the metal bonding surface 22 of the metal member 20 can form a covalent bond by a neutralization reaction. In addition, the second temperature T2 is preferably: the temperature at which water produced by the neutralization reaction is removed from the reaction system. The second temperature T2 varies depending on the type of the functional group and the metal oxide, and therefore, it is difficult to determine the temperature without distinction, but is more preferably 100 ℃ or higher in view of easy removal of water generated by the neutralization reaction.

In the second step, the pressure P at which the synthetic resin member 10 is pressed against the metal member 20 is preferably a pressure equal to or higher than the compressive yield stress of the thermoplastic resin constituting the synthetic resin member 10. The pressure P varies depending on the thermoplastic resin constituting the synthetic resin member 10, and therefore, it is difficult to determine the pressure without distinction, and is preferably 10 to 100 MPa.

In the second step, the moving speed V of the synthetic resin member 10 when the synthetic resin member 10 is caused to collide with the metal member 20 is not particularly limited, and may be set to 50 to 150 mm/sec. The time S2 for pressing the synthetic resin member 10 against the metal member 20 is not particularly limited, and may be set to 1 to 10 seconds.

In the present embodiment, the description has been given of the case where the pressing device 53 moves the synthetic resin member 10 toward the metal member 20, but the metal member 20 may be moved toward the synthetic resin member 10.

In the present embodiment, the case where the metal member 20 and the synthetic resin member 10 are partially joined has been described, but the synthetic resin member 10 and the metal member 20 may be joined in a wide range. The planar shape of the joint portion may be any shape such as a dot, a line, or a plane.

(5) Effect

In order to firmly join the synthetic resin member 10 and the metal member 20, it is necessary to bring the thermoplastic resin constituting the synthetic resin member 10 and the metal material constituting the metal member 20 close to about several nm so that the thermoplastic resin and the metal material chemically react. In the method of manufacturing the metal-resin bonded body 30 of the present embodiment, the resin bonded surface 12 of the synthetic resin member 10 is exposed to a gas heated to a first temperature T1 equal to or higher than the deflection temperature Tf under load to lower the viscosity of the thermoplastic resin located on the resin bonded surface 12, and then the resin bonded surface 12 and the metal bonded surface 22 are bonded. Therefore, in the present embodiment, even if the metal bonding surface 22 has minute irregularities, the resin bonding surface 12 deforms following the irregularities, chemical reaction is likely to occur between the thermoplastic resin and the metal material, and the synthetic resin member 10 and the metal member 20 can be firmly bonded.

In the present embodiment, the synthetic resin member 10 and the metal member 20 can be joined by locally heating the vicinity of the resin joining surface 12, and the synthetic resin member 10 does not need to be entirely heated to a high temperature, so that deformation of the synthetic resin member 10 can be suppressed.

In the present embodiment, the resin joint surface 12 of the synthetic resin member 10 and the metal joint surface 22 of the metal member 20 may be joined to each other after the temperature of the resin joint surface 12 and the metal joint surface 22 is lowered to the second temperature T2 lower than the first temperature T1. When the temperature is lowered to the second temperature T2 and then the joining is performed, the synthetic resin member 10 can be further suppressed from being deformed when the synthetic resin member 10 and the metal member 20 are joined.

In the present embodiment, the second temperature T1 may be set to a temperature lower than the melting point Tm of the thermoplastic resin constituting the synthetic resin member 10. In this way, when the second temperature T2 is lower than the melting point Tm of the thermoplastic resin, the deformation of the synthetic resin member 10 occurring when the synthetic resin member 10 and the metal member 20 are joined can be further suppressed.

In the present embodiment, the metal member 20 may be heated in a state where the synthetic resin member 10 and the metal member 20 are arranged to face each other with a space therebetween. In this case, the gas between the synthetic resin member 10 and the metal member 20 can be heated to the first temperature T1 by the heat of the metal member 20, and the resin joint surface 12 can be exposed to the gas heated to the first temperature T1 by a simple configuration. Further, the second step of joining the synthetic resin member 10 and the metal member 20 can be continuously performed after the first step, and the metal-resin joined body 30 can be produced in a short time.

In the present embodiment, the heating device 52 can heat the metal member 20 by induction heating. In this case, a desired position of the metal member 20 is easily locally heated. In particular, induction heating of the metal member 20 facing each other with the synthetic resin member 10 interposed therebetween by the heating device 52 facilitates local heating of the vicinity of the metal joining surface 22 of the metal member 20. Therefore, the temperature of the gas in contact with the resin joint surface 12 of the synthetic resin member 10 can be easily controlled, and a firmly joined metal-resin joint body 30 can be obtained in the present embodiment even when joining by friction joining or laser welding is difficult as in the case where the metal member 20 is a hollow member or the case where the metal member 20 has a large volume.

In the present embodiment, after the temperature of the resin bonding surface 12 and the metal bonding surface 22 is lowered to the second temperature T2 lower than the first temperature T1, the pressure P when the synthetic resin member 10 is pressed against the metal member 20 may be set to: the pressure of the thermoplastic resin constituting the synthetic resin member 10 is not less than the compressive yield stress. In this case, the synthetic resin member 10 and the metal member 20 can be joined without using a die, and the tact time (the time from joining the synthetic resin member 10 and the metal member 20 to obtaining a practical strength) can be made short.

In this embodiment, the first step may be performed in an oxygen-containing gas. In this case, a functional group capable of chemically bonding by neutralization reaction with a basic or amphoteric oxide is generated on the resin bonding surface 12 of the synthetic resin member 10. The functional group formed on the resin bonding surface 12 bonds to the metal oxide present on the metal bonding surface 22 of the metal member 20 by dipole interaction, and forms a covalent bond by a neutralization reaction (dehydration condensation) with the metal oxide of the metal member 20. Therefore, when the first step is performed in the oxygen-containing gas, the synthetic resin member 10 and the metal member 20 can be more firmly joined.

In this embodiment, the step of roughening the surface of the metal member may be performed. In this case, the synthetic resin member 10 and the metal member 20 can be more firmly joined by the anchor effect.

Further, if the rod 54 pressing the synthetic resin member 10 toward the metal member 20 as in the present embodiment is inserted into the hollow portion of the induction heating coil of the heating device 52 heating the metal member 20 and penetrates through the hollow portion, even when the bonding area between the synthetic resin member 10 and the metal member 20 is small, the bonding portion can be reliably heated and pressed.

In the present embodiment, the tip shape of the rod 54 of the pressing device 53 is reduced, so that the bonding area between the synthetic resin member 10 and the metal member 20 can be reduced, and the synthetic resin member 10 and the metal member 20 can be easily and partially bonded. If the synthetic resin member 10 and the metal member 20 are locally joined, even if the linear expansion coefficients of the synthetic resin member 10 and the metal member 20 are different, the force generated in the metal-resin joined body 30 during thermal expansion is not easily concentrated on the joined portion, and the metal-resin joined body 30 having excellent thermal durability can be obtained. Further, when the synthetic resin member 10 is intentionally peeled off from the metal member 20 as in the case of recycling, the peeling can be relatively easily performed by concentrating the force on the local joining portion. That is, in the manufacturing method of the present embodiment, the metal-resin bonded body 30 excellent in thermal durability and recycling property can be easily manufactured.

(examples)

The metal-resin bonded bodies (test pieces) of examples 1 to 16 and comparative examples 1 to 8 were prepared so as to specifically show the effects of the above-described embodiments.

In examples 1 to 16, the production method (4) was carried out in air to produce a metal-resin bonded body. That is, the test pieces of examples 1 to 16 were produced by exposing the surface of the synthetic resin member to a gas heated to a first temperature T1 equal to or higher than the deflection temperature under a load of the thermoplastic resin applied with a load of 1.8MPa, and then bonding the surface of the synthetic resin member and the surface of the metal member while applying a pressure of 20MPa at a second temperature T2. In examples 1 to 16, the types of the synthetic resin members and the metal members for bonding, the first temperature T1, and the second temperature T2 are shown in tables 1 and 2.

In comparative examples 1 to 8, the test pieces of comparative examples 1 to 8 were produced by exposing the surface of the synthetic resin member to a gas heated to a temperature ta lower than the deflection temperature under a load of the thermoplastic resin under a load of 1.8MPa in the air, and then bonding the surface of the synthetic resin member and the surface of the metal member while applying a pressure of 20MPa at the temperature tb. The metal parts, the synthetic resin parts, the temperature ta and the temperature tb used are shown in Table 3.

The dimensions of the metal members, the dimensions of the synthetic resin members, and the bonding areas (overlapping areas) between the synthetic resin members and the metal members used in examples 1 to 16 and comparative examples 1 to 8 are as follows.

Size of the metal part: 12mm × 35mm × 1.6mm

Size of the synthetic resin member: 12mm × 50mm × 1.5mm

Bonding area of metal member and synthetic resin member: 10mm by 5mm

The details of the metal parts and the resin parts in tables 1 to 3 are as follows.

PP resin: NOVATEC PP (registered trademark) HG30U

PA66 resin: leona 1300S

PBT resin: TORAYCON (registered trademark) 1101G-X54

PPS resin: SUSTEEL (registered trademark) SGX120

CFRTP resin: TORELINA (registered trademark) A630T-30V

PEEK resin: VICTREX PEEK 450G (registered trademark)

Al: a1050 having anodized surface

Fe: SPCC having its surface oxidized and roughened by heating to 1535 ℃ or higher melting point of Fe for 1 second by laser irradiation

SUS 304: SUS304 having its surface oxidized and roughened by heating to 1450 deg.C or higher, which is the melting point of SUS304, for 1 second by laser irradiation

Ti: class 2 pure titanium material having surface oxidized and roughened by heating to melting point of Ti of 1668 ℃ or higher for 1 second by laser irradiation

The metal-resin bonded bodies of examples 1 to 16 and comparative examples 1 to 8 were evaluated for the bonding strength and the rate of change in resin thickness. The evaluation methods are as follows.

Bonding strength: the dimensions of the metal member, the dimensions of the synthetic resin member, and the bonding area between the synthetic resin member and the metal member were changed as described above by the test method specified in JIS K6850, and the other conditions were measured at a tensile speed of 10mm/min and a measurement temperature of 25 ℃ by using a tensile tester (manufactured by Takeda Ltd., NV 301-NA).

Rate of change in resin thickness: the thickness th1 of the synthetic resin member before joining the metal member and the thickness th2 of the synthetic resin member after joining the metal member were measured, and the rate of change in the resin thickness ((th1-th2)/th1)) was calculated by dividing the amount of decrease in the thickness of the synthetic resin member (th1-th2) by the thickness th 1. The thickness th2 of the synthetic resin member after the metal member is joined is the thickness of the synthetic resin member measured at the position where the pressure is applied when the synthetic resin member and the metal member are joined.

The results are shown in tables 1 to 3.

TABLE 1

TABLE 2

TABLE 3

From the results shown in tables 1 to 3, it is understood that: in examples 1 to 16, the deformation of the synthetic resin member was suppressed and high bonding strength was obtained. In particular, in examples 9 to 16 in which the temperature at the time of joining the resin joining surface of the synthetic resin member and the metal joining surface of the metal member was set to a temperature lower than the melting point Tm of the thermoplastic resin constituting the synthetic resin member, it was possible to significantly suppress the deformation of the synthetic resin member while maintaining high joining strength.

Description of the symbols

10 … synthetic resin component, 12 … resin joint surface, 20 … metal component, 22 … metal joint surface, 30 … metal resin joint body, 50 … joint device, 51 … workbench, 52 … heating device, 53 … pressing device, 54 … rod and 55 … pressing device.