JP6476081B2 - Metal resin bonding member and method for manufacturing the same - Google Patents

Description

  The present invention relates to a metal-resin joining member obtained by joining a metal and a resin and a method for manufacturing the same.

  In recent years, with the need for weight reduction in the automobile field and the aircraft field, a highly reliable metal / resin joining member is required. In addition, since many electronic devices and power devices are sealed and packaged with resin, bonding with excellent high-temperature durability and the like is required even between the metal such as the wiring layer and the housing and the sealing resin. It has been. Joining metal and resin using an adhesive is also conceivable, but the use of an adhesive causes peeling due to deterioration over time, so it is not reliable and often involves the use of an adhesive solvent that is an environmentally hazardous substance. It is not preferable. Accordingly, various proposals have been made to join a metal and a resin without using an adhesive, and for example, there are descriptions related to the following patent documents.

JP 2013-52671 A Japanese Patent No. 5253416 Japanese Patent No. 4776515 Japanese Patent No. 4766176

  Patent Document 1 and Patent Document 2 propose that a metal surface that becomes a bonding interface is roughened and a metal and a resin are physically or mechanically bonded by a so-called anchor effect. In order to secure a high joint strength by the anchor effect, it is necessary to secure unevenness of a suitable size.

  Patent Document 3 states that an adhesion layer formed using a specific triazine compound is provided on the surface of the conductor metal in order to improve the adhesion between the conductor metal constituting the build-up multilayer printed wiring board and the interlayer resin. is suggesting. Such a method requires a complicated wet process and cannot be easily applied to various joining members.

  Patent Document 4 proposes joining rubber and a metal covered with a DLC film by sulfur crosslinking or peroxide crosslinking between the DLC film and the rubber. In this case, it is considered that a high bonding strength resulting from the chemical bonding force can be obtained. However, the bonding method of Patent Document 4 has a limited range of application when rubber is crosslinked with respect to a carbon-based DLC film ([0019], [0034], etc.) coated with metal.

  The present invention has been made in view of such circumstances, and an object thereof is to provide a metal resin bonding member that can be used relatively easily in various fields, and a method for manufacturing the same.

  The present inventor has intensively studied to solve this problem, and as a result of repeated trial and error, it has been found that a metal and a resin can be firmly bonded by a mechanism different from the conventional one. By developing this result, the present invention described below has been completed.

《Metal resin bonding member》
(1) metal-resin joint member of the present invention, the metal consisting of a metal body preliminarily surface covered with amorphous film, through the junction to the non AkiraTadashimaku joined to the metal member and resin member a resin bonding member, the resin body is seen containing an O or N in the functional group or in the main chain, wherein the amorphous film, the entire non-AkiraTadashimaku 100 atomic% (referred to simply as "%".) as, O: 1 to 40% and C: film thickness with containing 20-95% it is 0.01 to 10 [mu] m, further, not part of the resin body with no metal element in the metal side It is characterized by that.

(2) The metal-resin joining member of the present invention (simply referred to as “joining member”) can be relatively easily manufactured by a dry process in which a metal body and a resin body are firmly joined via an amorphous film. Therefore, the application range is wide and it can be used for various members in various fields.

  In addition, when the amorphous film functions as a shielding film (barrier layer) that suppresses diffusion (particularly diffusion of metal elements from the metal body to the resin body) that occurs between the metal body and the resin body, bonding caused by the diffusion Interface destruction and peeling are also suppressed. Thus, the joining member of the present invention has excellent durability or reliability for maintaining high joining strength over a long period of time.

  Furthermore, when the amorphous film functions as a protective film that suppresses oxidation or corrosion of the metal body, the bonding member of the present invention has excellent corrosion resistance and the like.

(3) By the way, although the mechanism by which the bonding member of the present invention exhibits high bonding strength between the amorphous film and the resin body is not necessarily clear, the present inventor has intensively studied. Conceivable.

  The joining member of the present invention exhibits high joining strength without depending on the physical joining force such as the conventional anchor effect. From this, it is considered that a chemical bonding force is generated between the amorphous film and the resin body. Factors that cause chemical bond strength (chemical factors) include van der Waals force, hydrogen bond, and covalent bond, but since the bond strength is remarkably high, there is a gap between the amorphous film and the resin body. Then, it is thought that the covalent bond has arisen.

  Specifically, O or N contained in the amorphous film is covalently bonded to a main component (for example, C or Si) constituting the amorphous film and a skeleton (main chain) in the resin body. ) Or an element constituting a functional group (for example, C), and the amorphous film and the resin body are considered to be firmly bonded. In order to generate such a covalent bond, it is necessary that the amorphous film contains O or N and the resin body is made of a resin that reacts with such an amorphous film to generate a covalent bond.

  Various kinds of such resins are conceivable, but according to the research conducted by the present inventor, those containing at least O or N in the functional group or main chain in the vicinity of the bonding interface are preferable. More specifically, for example, a functional group substituted on the main chain, and a functional group containing O or N in the amorphous film (the functional group containing O is appropriately referred to as “oxygen functional group”, N It is a resin (specific resin) capable of directly forming a covalent bond with a functional group containing the nitrogen group).

  In any case, the bonding member of the present invention has a high bonding strength because a covalent bond occurs at the interface between the resin body containing O or N in the functional group or main chain and the amorphous film containing O or N. It is thought that came to show.

<< Production Method of Metal Resin Bonding Member >>
The present invention can be grasped not only as a joining member but also as a manufacturing method thereof. That is, the present invention includes a supply step of supplying a softened or molten resin onto a metal body coated with an amorphous film, and a solidification step of solidifying the resin to form a resin body. Also, it can be grasped as a manufacturing method characterized in that the above-described metal resin bonding member is obtained. The present invention also includes a method for manufacturing a metal resin bonding member, comprising a pressure bonding step of heating and pressing a metal body and a resin body through an amorphous film, and obtaining the above-described metal resin bonding member. Good.

<Others>
Unless otherwise specified, “x to y” in this specification includes a lower limit value x and an upper limit value y. A range such as “a to b” can be newly established with any numerical value included in various numerical values or numerical ranges described in the present specification as a new lower limit value or upper limit value.

It is a schematic diagram explaining reaction which produces a covalent bond between an amorphous film and a resin body. It is a photograph which shows the peeling surface or fracture surface of each sample after a strength evaluation test.

  The contents described in this specification can be appropriately applied not only to the joining member of the present invention but also to the manufacturing method thereof. A component related to a manufacturing method can be a component related to an object if understood as a product-by-process claim. One or two or more components arbitrarily selected from the present specification may be added to the above-described components of the present invention. Which embodiment is the best depends on the target, required performance, and the like.

<Amorphous film>
(1) The amorphous film according to the present invention contains O or N. O or N is usually considered to exist as a functional group such as —OH (hydroxy group), —NH (imino group), —NH ₂ (amino group) in an amorphous film alone. For this reason, the amorphous film is more or less considered to contain H bonded to O or N termination or the like. Note that, in addition to the source gas, a slight amount of moisture contained in the chamber can also serve as a H supply source.

  In addition to O, N, and H, the amorphous film can contain various elements. For example, it is preferable that the amorphous film contains C or Si because it is chemically stable. As a result, the bonding interface is also stabilized, and high bonding strength can be maintained for a long time. In addition, a metal body coated with such an amorphous film can exhibit excellent corrosion resistance and the like. In particular, it is more preferable that the main component of the amorphous film is C or Si. Note that “main component” here means that the entire amorphous film is 100 at% (appropriately simply referred to as “%”), and the content of the element is the highest.

  Various constituent elements or component compositions of the amorphous film can be considered. Each element is, for example, N: 0.1 to 10%, further 0.2 to 5%, O: 1 to 40%, further 5 to 35%, H: It may be 40% or 10 to 35%, C: 20 to 95%, 25 to 85%, Si: 0.05 to 45%, or 0.1 to 30%.

  The film thickness of the amorphous film may be, for example, about 0.01 to 10 μm, 0.1 to 5 μm, and further about 0.5 to 3 μm. This is because it is sufficient to ensure the bondability between the metal body and the resin body and the corrosion resistance of the metal body. Note that it is sufficient that the amorphous film is at the bonding interface between the metal body and the resin body, but an amorphous film may be formed as a protective film or the like on the other surface of the metal body.

(2) The amorphous film can be formed by various methods. For example, the film can be formed by a plasma CVD method, an ion plating method, a sputtering method, or the like. When the plasma CVD method is used, uniform film formation is possible regardless of the shape of the metal body, and an amorphous film can be formed at low cost because it is not necessary to use a complicated film formation apparatus. . If a PVD method such as a sputtering method is used, a directional amorphous film can be easily formed.

  In the case of using the plasma CVD method, for example, it is preferable that the film-formed surface of the metal body is previously roughened (irregular formation) by an ion bombardment method. Thereby, the adhesiveness of a metal body and an amorphous film can be improved.

The plasma CVD method is performed as follows, for example. The inside of the container (chamber) in which the substrate is installed is set to a vacuum atmosphere. A pretreatment gas (for example, argon (Ar), hydrogen (H ₂ ), nitrogen (N ₂ )) is introduced into the container. Next, ion bombardment is applied to the surface of the metal body by glow discharge or ion beam. In this way, the bonding interface of the metal body is roughened. Thereafter, a reactive gas (and a carrier gas) is introduced into the container, plasma is generated by discharge, and a desired amorphous film is formed on the roughened processing surface.

For example, when an amorphous carbon film containing N (DLC-N film) is formed, a reactive gas containing a carbon-containing gas and a nitrogen gas may be used. As the carbon-containing gas, one or more selected from a carbocyclic compound gas and a heterocyclic compound containing N may be used. The carbocyclic compound is, for example, an aromatic hydrocarbon compound such as benzene, toluene, xylene, naphthalene. Examples of the heterocyclic compound containing N include aniline, azobenzene, pyridine, pyrazine, pyrrole, imidazole, and pyrazole. In addition to nitrogen (N ₂ ), nitrogen compounds such as ammonia, methylamine, dimethylamine, and trimethylamine may be mixed with the heterocyclic compound.

In the case of forming an amorphous film containing Si, as a reaction gas, in addition to an aromatic compound gas containing Si such as phenylsilane and phenylmethylsilane, Si (CH ₃ ) ₄ , Si (CH ₃ ) ₃ H, A silicon compound gas such as Si (CH ₃ ) H ₃ , SiH ₄ , Si (OC ₂ H ₅ ) ₄ , SiCl ₄ , SiH ₂ F ₄ may be used.

Hydrogen (H ₂ ), nitrogen (N ₂ ), argon, or oxygen (O ₂ ) can be used as a carrier gas introduced with the reaction gas.

The amorphous film preferably has a functional group such as —OH, —NH, and —NH _{2 on} the surface in advance, but these functional groups are formed on the surface of the amorphous film after the film reacts with the atmosphere. It may be generated.

《Metal body》
The joining member of the present invention is joined to the resin body through an amorphous film. For this reason, the metal body which concerns on this invention does not ask | require the material, a form, etc. as long as formation of an amorphous film and adhesiveness (peeling resistance) can be ensured. The metal body may be made of any metal such as pure copper / copper alloy, pure titanium / titanium alloy, pure aluminum / aluminum alloy, and pure iron / iron alloy.

  The adhesion between the metal body and the amorphous film can be enhanced by mechanical or chemical pretreatment (for example, sputtering, shot peening, etching, etc.) before film formation. The surface form of the metal body on which the amorphous film is formed is not limited, but the adhesion to the amorphous film can be improved by adjusting the surface roughness or surface area of the metal body. Also, since the film thickness of the amorphous film is usually several to several tens of μm at most, adjusting the surface roughness of the metal body can adjust the surface roughness of the amorphous film or increase the surface area. It becomes possible. When the surface roughness and the like of the amorphous film are appropriately adjusted, the area of the bonding interface between the amorphous film and the resin body increases, and the bonding strength between the two can be improved. At this time, there may be a contribution of physical bonding force (anchor effect) in addition to chemical bonding force (covalent bonding force).

<Resin body>
The resin body that is firmly bonded to the amorphous film may be made of a resin containing O or N in the functional group or main chain at least in the vicinity of the bonding interface with the metal body. As such a resin, the following specific resins can be considered at present.

The specific resin is a resin having a functional group substituted on the main chain and capable of directly forming a covalent bond with a functional group (oxygen functional group, oxygen functional group) containing O or N in the amorphous film. . For example, a resin having an epoxy group or an isocyanate group, or a resin containing maleic anhydride. The resin body according to the present invention is bonded to the metal body through a reaction (covalent bond) with the amorphous film. For this reason, the specific resin here refers to the state before joining to the metal body. For example, when the resin body is made of an epoxy resin which is one of the specific resins, the resin body indicates a state before heating and curing before joining with the metal body. This type of resin is attacked by a Lewis base (—OH, —NH, —NH _2, etc.) in which the functional group C exists on the surface of the amorphous film, and this C and O or N in the amorphous film And have a covalent bond. An example of a reaction in which a covalent bond thus occurs is schematically shown in (Ia), (Ib), or (Ic) of FIG.

  In addition, if the resin such as polypropylene (PP), polyethylene (PE), polyphenylene sulfide (PPS), polyvinylidene fluoride (PVDF), phenol resin, melamine resin is not modified, it is bonded (bonded) to the amorphous film. It is hard to do. However, if these resins are also modified to have epoxy groups, isocyanate groups, maleic anhydride, etc., they form a covalent bond with the amorphous film as in the case of the specific resin described above, and are firmly bonded. It becomes like this.

"Production method"
Various methods for manufacturing the joining member are conceivable. For example, a softened or melted resin is injected into a mold containing a metal body covered with an amorphous film (supply process), and the resin is cooled and solidified (solidification process). In this case, resin molding and joining are performed in one step, which is efficient. The resin molding may be performed by any of injection molding, extrusion molding, blow molding, vacuum molding, transfer molding, compression molding, and the like. A molding method suitable for the specifications of the joining member, the characteristics of the resin to be used, and the like is appropriately selected. In addition, the joining member may be performed by pressurizing and heating the metal body and the resin body through an amorphous film (crimping step).

  Note that the amorphous film and the resin are preferably bonded within a short time after the amorphous film is formed (for example, within 30 minutes after the film formation). When an amorphous film is exposed to the atmosphere for a long time after film formation, the activity of O or N (oxygen functional group or nitrogen functional group) in the vicinity of the outermost surface decreases, and the covalent bondability with the resin is reduced. Can be reduced.

《Joint member》
The joining member of the present invention is preferably used, for example, in various electronic devices, battery components, and their casings, connectors, and the like, because high reliability can be secured at low cost. As a specific example, the joining member of the present invention is suitable for a control device (ECU) having a wiring metal (metal body) and a sealing resin (resin body), a power module, and the like. In addition, the joining member of the present invention is also suitable for a seal portion for maintaining airtightness, waterproofing and heat insulation.

  A joined body (test material) obtained by integrally molding a metal and a resin covered with various amorphous films was manufactured, and the joint strength was evaluated. Through these, the present invention will be described more specifically.

[Example 1]
<Deposition of amorphous film>
An oxygen-free copper plate (manufactured by Mitsubishi Shindoh Co., Ltd.) was prepared as a metal body. Various amorphous films shown in Table 1 were formed on the surface of this oxygen-free copper plate (simply called “copper plate”) by plasma CVD. Specifically, the film was formed as follows.

A copper plate was set in the chamber, and the inside of the chamber was evacuated. Hydrogen (H ₂ ) and argon were introduced into this chamber. A DC voltage was applied to the copper plate in the chamber to cause discharge, and the copper plate was heated to a predetermined film formation temperature (400 to 600 ° C.) by ion bombardment and roughened (pretreatment step).

  Next, a reactive gas was introduced into the chamber and a film was formed by plasma CVD. All film thicknesses were about 200 nm. Tetramethylsilane, pyridine, toluene, and tetraethoxysilane were used as the reaction gas. Each amorphous film shown in Table 1 was formed by adjusting the kind or concentration of the reaction gas.

《Membrane analysis》
The composition near the surface of each amorphous film was analyzed as follows. First, the amount of H (average value) in the film was determined by dynamic SIMS (secondary ion mass spectrometry). This amount of H was taken as the amount of H on the film surface. Next, C, N, O and Si contained in the film were detected by XPS (X-ray photoelectron spectroscopy). Based on these detection results and the previously determined H amount, the composition (atomic ratio) of C, N, O and Si in the film was determined. Table 1 shows the composition of the film surface thus identified (a few nm region from the outermost surface).

  As is clear from Table 1, all of the amorphous films contained O and H, and Sample 2 and Sample 3 also contained N. In addition, it is confirmed by XRD (X-ray diffraction) performed separately that each film is an amorphous film.

<< Manufacture of joining members >>
An uncured epoxy resin (E500 manufactured by Sumitomo Bakelite Co., Ltd.) for semiconductor encapsulation was prepared as a raw material for the resin body. The copper plate coated with the amorphous film was set in an insert mold (mold). The mold and the copper plate were heated to raise the molding temperature (170 to 180 ° C.). An epoxy resin heated and melted at 175 ° C. was poured onto an amorphous film of a copper plate set in the mold, and then cooled and solidified. In this way, a test material (joining member) was obtained in which a pudding cup-shaped resin body was molded and joined on the amorphous film covering the copper plate.

<Strength evaluation>
The bonding strength of each test material was measured as follows. A jig is pressed against the resin body to apply a shearing force between the amorphous film and the resin body. The shearing force when peeling at the bonding interface or when the resin body was destroyed was measured. Table 1 also shows the peel strength obtained by dividing the shear force thus obtained by the bonding area between the resin body and the amorphous film.

  In either case, it was confirmed that cohesive failure of the resin body occurred first and sufficient bonding strength was obtained. By the way, using a copper plate not covered with an amorphous film (however, covered with a naturally formed oxide film), the peel strength (joint strength) of a similarly manufactured specimen was also measured. (Comparative example). In this comparative example, it was confirmed that peeling occurred between the copper plate and the copper oxide film.

  From the above, it has been clarified that the metal body and the resin body can be firmly bonded by interposing the amorphous film containing O or N at the bonding interface.

[Example 2]
<< Film formation and film analysis >>
An amorphous thin film having a thickness of about 15 nm was formed on the surface of a pure titanium plate (simply called “Ti plate”) in the same manner as in Example 1. The composition near the surface of this amorphous thin film was similarly analyzed by the method described above. The results are shown in Table 2.

  As is clear from Table 2, it was confirmed that the amorphous thin film according to this example also contains O, N, and H. Note that it is confirmed by XRD (X-ray diffraction) performed separately that this film is an amorphous film.

<< Manufacture of joining members >>
Two Ti plates (40 mm × 10 mm × 0.6 mm thickness) coated with the above amorphous thin film, maleic anhydride-containing polypropylene sheet (10 mm × 10 mm × thickness 1.0 mm / simply “PP sheet”) ). At this time, each amorphous thin film was brought into contact with the PP sheet.

  The laminated Ti plate and PP sheet were pressed at 2 MPa from the outer surface of each Ti plate. This pressurization was performed in an air atmosphere heated to 150 ° C. (compression bonding step). This treatment was performed on a plurality of PP sheets having different maleic anhydride contents relative to the whole (Samples 21 to 23).

<Strength evaluation>
The Ti plate of each test material (joining member) thus obtained was pulled at 20 mm / min from both ends, and the joining strength (shear strength) for each sample was determined from the measured load when it was peeled off or broken. The results at this time are also shown in Table 2. The state of each sample after this strength evaluation test is shown in FIG.

  Accordingly, when the content of maleic anhydride is appropriate, the bonding strength is increased, and the fracture surface is separated from the interface between the amorphous thin film (metal body side) and the PP sheet (resin body side), and the PP sheet (resin body). ) It became clear to shift to cohesive failure of itself. More specifically, as shown in FIG. 2, in the sample 21, there is almost no PP remaining on the Ti plate on one side (left side in FIG. 2), and interface peeling occurs between the amorphous thin film and PP. Recognize. On the other hand, in sample 22 and sample 23, it can be seen that there is PP remaining on the Ti plate on one side, and the PP sheet itself is broken (cohesive failure). It can be seen that the sample 23 having a higher content (ratio) of maleic anhydride has more PP remaining on the Ti plate on one side, and the bonding strength between the amorphous thin film and the PP sheet is higher.

  From the above, the resin body and the metal body are firmly bonded by the reaction between O contained on the resin body side and the oxygen functional group or nitrogen functional group present on the surface of the amorphous film covering the metal body side. It was confirmed that

Claims (9)

A metal body preliminarily surface covered with amorphous film, a metal-resin joint member comprising a resin body which is joined to the metal body through a bonding to non AkiraTadashimaku,
The resin body is seen containing an O or N in the functional group or in the main chain,
The amorphous film, the entire non-AkiraTadashimaku as 100 atomic% (referred to simply as "%".), O: 1 to 40% and C: 20 to 95% at a film thickness 0.01~10μm with including And a metal resin bonding member characterized by not containing a metal element on the metal body side and not being a part of the resin body . The metal-resin bonding member according to claim 1, wherein the amorphous film further contains N 10 : 0.1 to 10%. The metal-resin bonding member according to claim 2 , wherein the amorphous film further includes H: 5 to 40% and Si: 0.1 to 30%, and the balance is made of C and impurities .
The metal-resin bonding member according to claim 2 , wherein the amorphous film further includes H: 5 to 40%, and the balance is C and impurities . The surface of the metal body is coated with amorphous film is metal-resin joint member according to any one of claims 1 to 4 which is roughened.   The metal resin bonding member according to any one of claims 1 to 5, wherein the resin body is made of a resin having an epoxy group or an isocyanate group or containing maleic anhydride. A supply step of supplying a softened or melted resin onto the amorphous film of the metal body coated with the amorphous film;
A solidification step of solidifying the resin into a resin body,
A method for producing a metal resin bonded member, wherein the metal resin bonded member according to claim 1 is obtained. A pressure bonding step of pressing while heating the metal body and the resin body through the amorphous film,
A method for producing a metal resin bonded member, wherein the metal resin bonded member according to claim 1 is obtained.   9. The method for manufacturing a metal resin bonded member according to claim 7, wherein the amorphous film is formed on the metal body by a plasma CVD method performed in a vacuum atmosphere.