JP2014136366A - Method for manufacturing an aluminum-resin joined body and aluminum-resin joined body - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for manufacturing an aluminum-resin joined body having an extremely high joining strength between an aluminum substrate and a resin member; and an aluminum-resin joined body.SOLUTION: In the provided method for manufacturing an aluminum-resin joined body, an etching gas including chlorine atom-containing gas molecules and water molecules is jetted, after having been mixed with a plasma jet, onto an aluminum substrate. A thermoplastic resin is induced to infiltrate multiple valley portions included among valley and peak portions of the aluminum substrate thus formed and then is solidified so as to obtain, by forming a fitting interface of the resin member, an aluminum-resin joined body in which the aluminum substrate and resin member are joined; an aluminum-resin joined body thus obtained is also provided.

Description

  The present invention relates to a method of manufacturing an aluminum / resin bonded body in which an aluminum base material and a resin member are integrally and firmly bonded together, and an aluminum / resin bonded body.

In general, in the transportation equipment industry centering on automobiles and the like, application of an aluminum base material that is lightweight and excellent in workability, corrosion resistance, and the like is expanding for reasons such as CO ₂ reduction. On the other hand, since the resin is also lightweight and excellent in moldability, its application range is expanding as one of means for reducing the weight. Further, attention is also focused on an aluminum / resin bonded body obtained by integrally bonding them.

  Conventionally, in order to obtain an aluminum / resin bonded body in which an aluminum base material and a resin, which are different materials, are integrally bonded to each other, a resin molded body and an aluminum base material in which resin is molded in advance are used. A technique has been adopted in which these are bonded under pressure with an adhesive. In recent years, as an industrially excellent joining method, an aluminum base material is inserted into an injection mold, and a molten thermoplastic resin is injected toward the surface of the inserted aluminum base material to provide thermoplasticity. A method is known in which a resin molded body is molded by resin injection molding, and at the same time, an aluminum substrate and a resin molded body are joined.

  For example, in Patent Document 1, an aluminum shaped body is etched with an acid aqueous solution to form uneven portions on the surface, and a resin molded body in which a thermoplastic resin enters and solidifies into a plurality of recessed portions due to the uneven portions. There has been proposed an aluminum / resin injection integrated molded product in which an aluminum shaped body and a resin molded body are locked together by forming a fitting portion. Patent Document 2 discloses an aluminum alloy member in which a surface of an Al-Si alloy cast member is subjected to chemical etching treatment with an acid-based liquid, and a concave portion having a plurality of convex portions made of eutectic Si crystals is formed on the inner surface. It is disclosed that resin bondability is excellent. Furthermore, Patent Document 3 and Patent Document 4 disclose a composite in which an aluminum alloy shaped article immersed in an aqueous solution of a water-soluble amine compound such as ammonia or hydrazine and a thermoplastic resin composition are integrated by injection molding. Has been.

  However, in the wet surface treatments described in these Patent Documents 1 to 4 and the like, waste liquid is generated, so that the treatment may be a problem, and when only trying to treat the portion where the resin is to be joined However, a process such as masking is required separately, and as a result, an increase in cost is inevitable.

On the other hand, as a dry surface treatment, for example, in Example 1 of Patent Document 5, an aluminum plate treated by vacuum plasma treatment using argon, oxygen, nitrogen, CF ₄ / oxygen, and ethylene is installed in a mold. In addition, it is described that a resin / metal composite was obtained by injection molding of a thermoplastic elastomer composition. It is said that there was no deviation from the position. Further, although different from the treatment relating to an aluminum substrate such as aluminum or aluminum alloy, Patent Document 6 discloses that an organic compound film is formed by plasma etching after forming an organic compound film on the surface of a substrate such as silicon. It is described that it can be used for the bonding portion by forming irregularities on the surface.

  However, even if the plasma treatment as described in Patent Documents 5 and 6 is performed, it is not possible to obtain a sufficient bonding strength between the aluminum base material and the resin, and at the bonding interface between the aluminum base material and the resin. It was inferior in strength reliability.

WO2009 / 151099A1 brochure JP 2010-174372 A Japanese Patent No. 3954379 Japanese Patent No. 4270444 JP 2001-239548 A JP 2003-66203 A

  Therefore, in view of the conventional technology as described above, the present inventors use plasma treatment to obtain an aluminum / resin bonded body having extremely high bonding strength between an aluminum base material and a resin member made of a thermoplastic resin. As a result of diligently examining the means, the predetermined etching gas is mixed with the plasma jet and sprayed onto the aluminum base material, and the surface of the aluminum base material is roughened to bond the aluminum base material to the resin member. The present invention has been completed by finding that an aluminum / resin bonded body having significantly improved properties can be obtained.

  Accordingly, an object of the present invention is to provide a method for producing an aluminum / resin bonded body capable of obtaining an aluminum / resin bonded body having extremely high bonding strength between an aluminum base and a resin member.

  Another object of the present invention is to provide an aluminum / resin bonded body having extremely high bonding strength between an aluminum base and a resin member.

  That is, the present invention relates to a method for producing an aluminum / resin joined body in which an aluminum base material made of aluminum or an aluminum alloy and a resin member made of a thermoplastic resin are joined, wherein a gas molecule containing chlorine atoms and water An etching gas containing molecules is mixed with a plasma jet, and the resulting mixed plasma jet is sprayed onto an aluminum substrate to roughen part or all of the surface of the aluminum substrate, and then formed by the roughening process. An aluminum / resin joint in which a thermoplastic resin is allowed to enter and solidify into a plurality of concave portions due to the uneven portions of the aluminum base material, and a resin member fitting portion is formed to join the aluminum base material and the resin member. A method for producing an aluminum / resin bonded body characterized in that a body is obtained.

  The present invention also relates to an aluminum / resin joined body in which an aluminum base material made of aluminum or an aluminum alloy and a resin member made of a thermoplastic resin are joined, and a part or all of the surface of the aluminum base material is chlorine. Roughening treatment is performed with a mixed plasma jet obtained by mixing an etching gas containing gas molecules containing atoms and water molecules with a plasma jet. An insertion portion of a resin member into which a thermoplastic resin has entered and solidified is formed in a plurality of resulting recess portions, and the aluminum base and the resin member are locked to each other by the recess portion and the insertion portion. This is an aluminum / resin bonded body.

In the present invention, the surface of the aluminum base material is roughened by mixing an etching gas containing gas molecules containing chlorine atoms and water molecules with a plasma jet and spraying the mixture onto the aluminum base material. By using such a mixed plasma jet, the mechanism by which the concavo-convex part is formed on the surface of the aluminum base material is not necessarily clarified, but at present, it is presumed as follows. Here, the case where the gas molecule containing chlorine atoms is HCl will be described as an example, and the reaction with the aluminum substrate is considered as follows.
HCl → H + Cl
Al + 3Cl → AlCl ₃
Al + Cl → AlCl

That is, it is considered that an etchant gas containing HCl and water molecules is mixed with a plasma jet to be turned into plasma, and chlorine plasma (Cl radical) is generated. Then, this mixed plasma jet containing Cl radicals is jetted to react with Al (metal aluminum) to form AlCl ₃ and AlCl, and these are vaporized to form uneven portions, and the surface of the aluminum substrate Is thought to be roughened.

Although this example has been described using HCl, it is only necessary to generate Cl radicals necessary for the reaction with Al (aluminum metal) as described above. In addition to HCl, for example, Cl ₂ (chlorine gas), Gas molecules containing Cl atoms such as CCl ₄ (carbon tetrachloride), BCl ₃ (boron trichloride) and the like can be used. Of these, HCl is preferable because an aqueous solution is formed and an etching gas containing water molecules is easily obtained. That is, for example, by heating and vaporizing hydrochloric acid, an etching gas containing hydrogen chloride (HCl) gas and water molecules (water vapor) can be easily created. At that time, the hydrochloric acid is preferably set to a temperature of 50 ° C. or more in order to easily secure the supply amount of HCl. However, if it exceeds 90 ° C, there is a risk of heating hydrochloric acid, so hydrochloric acid is kept at a temperature of 90 ° C or lower.

As for the role of water molecules (gas) in the etching gas, in addition to the function of diluting the concentration of gas molecules containing chlorine atoms, the etchant gas is ionized to OH ⁻ by mixing with the plasma jet, and Al It is expected that some of the metal oxides are oxidized to form aluminum oxide such as Al ₂ O ₃ or the surface of the aluminum base material is modified with hydroxy groups. That is, it is considered that a part of the surface of the aluminum base material contributes to roughening by partially forming aluminum oxide crystals or separating them. In addition, the aluminum base material modified with a hydroxy group can be considered to have a chemical bond with the resin member and improve the adhesion strength.

  In the present invention, a plasma generating gas such as argon, helium, nitrogen, dry air, etc. may be used to obtain a plasma jet mixed with an etching gas. Then, when mixing the etching gas and the plasma jet to obtain a mixed plasma jet, it is preferable to use a mixing nozzle having a coaxial double tube structure having an outer tube and an inner tube, under atmospheric pressure. It is preferable to eject the mixed plasma jet.

  That is, using a plasma generator having a coaxial double tube structure mixing nozzle, an etching gas is jetted from the outer tube side of the tip of the mixing nozzle, and a plasma jet is generated from the inner tube side of the tip. It is preferred that the etching gas be mixed with the plasma jet in the downflow region so that it is ejected. By doing in this way, it can be mixed with etching gas, without reducing the production efficiency of a plasma jet. At that time, the remote type can be used by separating the plasma generation part (electrode) from the process part (processing object) by installing the aluminum base material downstream of the mixing nozzle and ejecting the mixed plasma jet onto the surface of the aluminum base material. It becomes possible to perform plasma jet processing. Therefore, it is excellent in accessibility to the aluminum base material, and a portion where the resin member is desired to be joined can be selectively roughened. In general, the size of the atmospheric pressure plasma jet is several mm to several hundred μm, and therefore, it is only necessary to repeat the local roughening treatment of the treatment size according to this size as necessary. In addition, since the roughing treatment of the aluminum base material can be performed under atmospheric pressure, a special exhaust device or pressure vessel is not required, the device can be simplified, and the device cost (processing cost) can be reduced. High density is possible due to high density and high reactivity.

  In the present invention, the conditions for generating the plasma jet are not particularly limited, and known conditions can be employed. For example, as a plasma jet generation power source, those with steady operation include DC drive, microwave drive, low frequency drive such as sine wave and pulse, and RF (high frequency) drive. Among these, since the loss rate due to the diffusion and flow of plasma particles increases as the size decreases, a higher drive frequency is advantageous so that power can be efficiently injected into a small volume, but is not particularly limited thereto. In addition, the plasma jet generating electrode can be either a single electrode type or a bipolar electrode type, but from the viewpoint of promoting the plasma spraying effect on the aluminum substrate, it is applied to the aluminum substrate during the roughening treatment. It is desirable to apply a potential. For example, when generating a low-frequency pulse-driven atmospheric pressure plasma jet, it is desirable to apply a pulse-driven high voltage with a voltage of 5 kV or higher and a frequency of 1 kHz or higher in order to generate discharge. In order to obtain a bond excellent in adhesiveness with the resin member, it is desirable to spray the mixed plasma jet onto the aluminum base material in an injection time of at least about 10 minutes.

  When a mixing nozzle having a coaxial double pipe structure is used, for example, a plasma generating gas such as argon or helium is supplied to the inner pipe side at a gas flow rate of about 1000 to 5000 sccm. In addition, on the outer tube side, an etching gas containing gas molecules containing chlorine atoms and water molecules is supplied together with an accompanying gas such as argon, helium, nitrogen, etc., and mixed with a plasma jet. It is good.

And the uneven | corrugated | grooved part formed in the aluminum base material by such a roughening process forms the insertion part of the resin member into which the thermoplastic resin approached and solidified in the some recessed part resulting from it, and the aluminum base material of The concave portion and the fitting portion of the resin member are locked to each other, and an aluminum / resin bonded body in which the aluminum base material and the resin member are integrally coupled can be obtained. Regarding the reason why the concave portion is formed, it is considered that the aluminum base material usually has a thin alumina surface layer made of Al ₂ O _{3 on the} surface thereof, but the alumina surface layer partially has defects. Therefore, the reaction of metal aluminum by the Cl radical as described above is preferentially started from these defects, and as a result, a concave portion is formed on the surface of the aluminum base material from which the mixed plasma jet is ejected. .

  Also, the metal aluminum inside the aluminum base material proceeds faster than the alumina surface layer, as in the reaction at the defect, and as a result, the reaction of the alumina surface layer and the metal aluminum immediately below it is delayed. For this reason, it is conceivable that the portion where the reaction is delayed remains as a snow candy-like protrusion when the reaction of the metal aluminum that has started from the defect of the alumina surface layer proceeds to the inside. That is, the aluminum base material on which the mixed plasma jet is sprayed has a snow flake shape from a part or the whole of the opening edge of the concave part toward the center in the opening width direction in part or all of the plurality of concave parts. In this case, the protruding portion may form a locking structure in which the concave portion of the aluminum base and the insertion portion of the resin member cannot be detached from each other. A strong bonding interface can be obtained.

  Here, regarding the roughening treatment of the aluminum base material by jetting of the mixed plasma jet, the center line average roughness Ra (JIS B 0601-1982) of the JIS standard in the uneven portion of the aluminum base material formed by the roughening treatment is 200 nm. The center line average roughness Ra is preferably 250 nm or more and 1500 nm or less, preferably 2000 nm or less. If Ra is less than 200 nm, poor adhesion may occur. Conversely, if Ra exceeds 2000 nm, there is a problem that it takes too much time for the surface treatment.

  In addition, as described above, it is preferable to perform the roughening treatment of the aluminum base material to the extent that the protruding portion protruding in the shape of a snow flake is formed in the concave portion, in order to obtain a stronger bonding interface, In this case, when the aluminum substrate is viewed in a longitudinal section cut in the thickness direction, the concave portion having a protruding portion protruding in a snow candy shape has a maximum opening width of 1 μm to 100 μm, preferably 2 μm to 80 μm. The height from the deepest part to the opening edge is 1 μm or more and 100 μm or less, preferably 2 μm or more and 90 μm or less.

  In the present invention, for the aluminum base material that has been roughened by ejecting a mixed plasma jet, for example, it is set in an injection mold, and a molten thermoplastic resin is injected into the mold. By integrally molding with a thermoplastic resin using a so-called aluminum base material, which is solidified, an aluminum / resin joined body of the target aluminum base material and the resin member can be obtained. Alternatively, a predetermined resin member is formed by injection molding of a thermoplastic resin in advance, and the obtained resin member is laser welded, vibration welded, ultrasonic welded, hot press welded on a roughened aluminum base material. By integrally joining by thermocompression using means such as hot plate welding, non-contact hot plate welding, or high frequency welding, an aluminum / resin bonded body of the target aluminum substrate and resin member is obtained. May be. In these cases, the resin member may be bonded to a part of the surface of the aluminum base material so as to correspond to the portion where the mixed plasma jet is injected. May be combined in a butted state.

  Here, in the case of injection molding of a thermoplastic resin performed by setting an aluminum base in an injection mold, normal molding conditions required for the thermoplastic resin used can be adopted. It is important that the thermoplastic resin melted at the time of injection molding enters into the concave part of the aluminum base material and solidifies, and the mold temperature and cylinder temperature allow the type and physical properties of the thermoplastic resin, as well as the molding cycle. It is preferable to set the temperature relatively high in the range. In particular, for the mold temperature, the lower limit temperature needs to be 90 ° C. or higher, preferably 130 ° C. or higher, but the upper limit depends on the type of thermoplastic resin used. In the range from 100 ° C. to a temperature about 20 ° C. lower than the melting point or softening point of the thermoplastic resin (when an elastomer component as described later is added, the higher melting point or softening point). It is preferable that. Further, the lower limit mold temperature is preferably set so as not to be lowered by 140 ° C. or more from the melting point of the thermoplastic resin.

  In the present invention, the aluminum base material forming the aluminum / resin bonded body is not particularly limited, but specific examples include, for example, pure Al 1000 series, Al-Cu 2000 series, and Al-Mn 3000 series. Series, Al-Si 4000 series, Al-Mg 5000 series, ADC5 and ADC6, Al-Mg-Si 6000 series, Al-Zn-Mg 7000 series, Al-Fe 8000 series , Al-Si-Mg-based ADC3, Al-Si-Cu-based ADC10, ADC10Z, ADC12, and ADC12Z, Al-Si-Cu-Mg-based ADC14, and the like made of aluminum or an aluminum alloy. . Then, when obtaining an aluminum / resin bonded body to be used in various structures and parts, these may be appropriately processed, or may be appropriately combined to form an aluminum base material having a desired shape.

  For these aluminum substrates, before spraying the mixed plasma jet, if necessary, for the purpose of degreasing and surface adjustment, removal of surface deposits and contaminants, acid treatment with an acid aqueous solution, and / or A pretreatment consisting of an alkali treatment with an alkali solution may be performed. Here, examples of the acid aqueous solution used for this pretreatment include those prepared with commercially available acid degreasing agents, mineral acids such as sulfuric acid, nitric acid, hydrofluoric acid, and phosphoric acid, organic acids such as acetic acid and citric acid, and the like. What was prepared using acid reagents, such as a mixed acid obtained by mixing acid, can be used, and as alkaline aqueous solution, for example, what was prepared with a commercially available alkaline degreasing agent, caustic soda, etc. What was prepared with the alkali reagent, or what was prepared by mixing these things etc. can be used. About the operation method and process conditions of the pre-processing performed using these acid aqueous solution and / or alkali aqueous solution, the operation method and process conditions of the pre-processing conventionally performed using this kind of acid aqueous solution or alkali aqueous solution, and For example, it can be performed by a method such as an immersion method or a spray method.

  In addition, after the above pretreatment is performed on the surface of the aluminum base material or after the uneven portion is formed by the roughening treatment in which the mixed plasma jet is jetted, the water washing treatment may be performed if necessary. Can use industrial water, ground water, tap water, ion-exchanged water, and the like. Furthermore, the aluminum base material that has been subjected to pretreatment or roughening treatment is subjected to a drying treatment if necessary, and this drying treatment may be natural drying that is allowed to stand at room temperature, as well as an air blow, a dryer, an oven, etc. Forced drying may be performed using

  On the other hand, as the thermoplastic resin forming the aluminum / resin bonded body, various thermoplastic resins can be used alone, but preferably, for example, polypropylene resin, polyethylene resin, acrylonitrile / butadiene / styrene copolymer (ABS). ), Polycarbonate resins, polyamide resins, polyarylene sulfide resins such as polyphenylene sulfide (PPS), polyacetal resins, liquid crystalline resins, polyester resins such as polyethylene terephthalate (PET) and polybutylene terephthalate (PBT), polyoxymethylene resins, Examples thereof include polyimide resins, syndiotactic polystyrene resins, and mixtures of two or more of these thermoplastic resins. In addition, in order to further improve performance such as adhesion between the aluminum base and the resin member, mechanical strength, heat resistance, dimensional stability (deformation resistance, warpage, etc.), electrical properties, etc., these thermoplastics You may make it add fillers, such as fibrous form, a granular form, and plate shape, and various elastomer components to resin.

  Here, as fillers added to the thermoplastic resin, inorganic fiber fillers such as glass fiber, carbon fiber, metal fiber, asbestos fiber and boron fiber, and high melting point organic fibers such as polyamide, fluororesin and acrylic resin are used. Examples include fillers, powder fillers such as quartz powder, glass beads, glass powder, and inorganic powders such as calcium carbonate, and plate fillers such as glass flakes and silicates such as talc and mica. It is done. When these additives are added to the thermoplastic resin, they are 250 parts by weight or less, preferably 20 parts by weight or more and 220 parts by weight or less, more preferably 30 parts by weight or more and 100 parts by weight with respect to 100 parts by weight of the thermoplastic resin. It is desirable to add in the following range. When the added amount of the filler exceeds 250 parts by weight, the fluidity is lowered, and it becomes difficult to enter the concave part of the aluminum base material, and there is a possibility that good adhesion strength cannot be obtained or the mechanical properties are deteriorated. .

  Examples of the elastomer component added to the thermoplastic resin include urethane type, core shell type, olefin type, polyester type, amide type, and styrene type elastomers. The melting temperature of the thermoplastic resin at the time of injection molding, etc. It can be selected in consideration. When these elastomer components are added to the thermoplastic resin, the amount is preferably 30 parts by weight or less, preferably 3 to 25 parts by weight based on 100 parts by weight of the thermoplastic resin. When the added amount of the elastomer component exceeds 30 parts by weight, a further effect of improving the adhesion strength is not seen, and problems such as a decrease in mechanical properties occur. The blending effect of the elastomer component is particularly prominent when a polyester resin is used as the thermoplastic resin.

  Furthermore, the thermoplastic resin for producing the aluminum / resin bonded body of the present invention includes known additives generally added to thermoplastic resins, that is, flame retardants, colorants such as dyes and pigments, antioxidants, Stabilizers such as ultraviolet absorbers, plasticizers, lubricants, lubricants, mold release agents, crystallization accelerators, crystal nucleating agents, and the like can be appropriately added according to the required performance.

  In the present invention, a method of mixing a predetermined etching gas with a plasma jet and injecting it onto the surface of the aluminum base material is adopted, so that there is no problem with waste liquid treatment as in the wet method. In addition, by using such a mixed plasma jet, it is possible to selectively process a portion where a resin member needs to be joined at a high speed, so that steps such as masking can be omitted. An aluminum / resin bonded body having extremely high adhesion strength at the interface with the member can be obtained easily and simply at low cost.

FIG. 1 is a schematic explanatory view of a surface treatment apparatus for an aluminum base material used in Examples. FIG. 2A is a photograph showing the mixing nozzle in the plasma generator from the tip and side, and FIG. 2B is a side cross-sectional view for explaining the mixing nozzle. FIG. 3 shows a voltage / current waveform of the power supply used in the example (in the case of voltage ± 5.0 kV, frequency 5 kHz, duty ratio 50%). FIG. 4 is a schematic explanatory diagram of an apparatus used for emission spectroscopic measurement for confirming the generation of chlorine plasma due to the plasma generation of the etching gas. FIG. 5 shows the results of emission spectroscopic measurement when the etching gas is turned into plasma. FIG. 6 is a SEM photograph (× 1000 times) of a cross-sectional observation of the roughened aluminum base material obtained in Example 1. FIG. 7 is a SEM photograph of the surface of the roughened aluminum base material obtained in Example 1 observed ((a) × 1000 times, (b) × 5000 times). FIG. 8 is an explanatory view schematically showing a part of the uneven portion formed on the surface of the roughened aluminum base material. FIG. 9 is an explanatory diagram for explaining the aluminum / resin bonded body manufactured in the example. FIG. 10 is an explanatory diagram for explaining an evaluation test method used when evaluating the bonding strength of the aluminum / resin bonded body manufactured in the example. FIG. 11 is a plane photograph of the roughened aluminum base material obtained in Example 5. FIG. 12 is a graph showing the relationship between the injection time of the mixed plasma jet and the surface roughness Ra of the aluminum base, based on the results obtained in Examples 1 to 6 and Comparative Example 1. FIG. 13A is an optical micrograph of the roughened aluminum base material according to Example 5 (× 200 times), and FIG. 13B is a partial AFM measurement result. FIG. 14A is an optical micrograph of an aluminum substrate according to Comparative Example 1 (× 200 times), and FIG. 14B is a partial AFM measurement result. FIG. 15A is an optical micrograph of an aluminum substrate according to Comparative Example 2 (× 200 times), and FIG. 15B is a partial AFM measurement result.

  Hereinafter, based on an Example and a comparative example, the manufacturing method of the aluminum resin joined body of this invention is demonstrated concretely. In addition, the following shows an example of the embodiment of the present invention, and the present invention is not limited to these contents.

[Generation of mixed plasma jet]
FIG. 1 schematically shows a state of a surface treatment apparatus that roughens the surface of an aluminum substrate using a mixed plasma jet. This aluminum substrate surface treatment apparatus includes a plasma generator 10 having a coaxial double tube structure mixing nozzle of an outer tube 1 and an inner tube 2, and an aluminum substrate W provided on a sample stage 11. A processing chamber 20 that is processed with a mixed plasma jet ejected from a gas cleaning bottle and an etching gas supply device 30 that supplies an etching gas to the outer tube 1 of the mixing nozzle in the plasma generator 10. Is done.

  Among these, as shown in FIG. 2, with respect to the plasma generator 10, a part of the inner side of the quartz glass inner tube 2 having a diameter (inner diameter) of 2 mm at the tip is externally formed of a glass tube having an outer diameter of 15 mm. A mixing nozzle having a coaxial double pipe structure that surrounds the tube 1 is formed, and an etching gas supplied from the connection port 1a of the outer tube 1 is ejected from the distal end and ejected from the distal end of the inner tube 2. Is mixed in the down flow region with the plasma jet. A copper foil tape is wound around the inner tube 2 as an electrode 3 for generating a plasma jet at a position approximately 100 mm from the tip of the mixing nozzle. And when performing the roughening process of an aluminum base material using this surface processing apparatus, the production | generation conditions of the following mixed plasma jets were employ | adopted.

First, 10% hydrochloric acid is put in the gas cleaning bottle of the etching gas supply device 30 and heated to 80 ° C., helium gas is injected from the gas inlet at a gas flow rate of 50 sccm (He-2), and the outer tube 1 is connected. An etching gas containing HCl gas and H ₂ O gas was supplied to the outer tube 1 from the gas outlet side connected to the port 1a. Further, helium gas was supplied to the inner tube 2 at a gas flow rate of 500 sccm (He-1). By applying a pulse driving high voltage with a voltage of ± 7.5 kV, a frequency of 5 kHz, and a duty ratio (Duty ratio) of 50% in a state where the gas flows in the outer tube 1 and the inner tube 2 of the mixing nozzle as described above, A low-frequency pulse-driven atmospheric pressure plasma jet is generated in the inner tube 2 and ejected into the atmospheric pressure from the inner tube side of the mixing nozzle tip, and the etching gas ejected from the outer tube side of the mixing nozzle tip Mixing was performed in the flow region to obtain a mixed plasma jet. Note that the SBP-10K-HF type manufactured by HEIDEN LABORATORY CO., LTD. Was used as the power source, and a semiconductor switching pulse generation method was adopted so that the rise time was 500 ns or less and the fall time was 500 ns or less. . FIG. 3 shows the case where the voltage is ± 5.0 kV, and the voltage when a pulse driving high voltage of voltage ± 5.0 kV, frequency 5 kHz, duty ratio 50% is applied using this power source. The current waveform is shown.

Further, in order to confirm that chlorine plasma is generated by the plasma of the etching gas, the following emission spectroscopic measurement was performed. Here, in order to confirm the Cl peak, which is weak light emission, a single tube nozzle as shown in FIG. 4 is used to contain HCl gas and H ₂ O gas upstream from the plasma jet generating electrode 3. Etching gas was supplied along with helium gas to make it plasma. Further, in the processing chamber 20, the light-receiving portion of the emission spectroscopic analyzer (OES) was protected by being inserted into a test tube, and measurement was performed from the downstream direction of the plasma jet. The other conditions were the same as the conditions for generating the mixed plasma jet in the previous surface treatment apparatus. The measurement results are as shown in FIG. 5, and a Cl peak could be confirmed from the plasma jet of the etching gas (479.4 nm). From this, it is considered that Cl radicals are also present in the mixed plasma jet in the previous surface treatment apparatus.

[Example 1]
An aluminum substrate having a size of 40 mm × 40 mm was cut out from a commercially available aluminum plate (A5052; plate thickness 2.0 mm) and attached to the sample stage 11 of the surface treatment apparatus shown in FIG. Then, a DC bias of 450 V is applied to the aluminum substrate W, and the mixed plasma jet is injected for 1 minute under the generation conditions of the mixed plasma jet described above with the inside of the processing chamber 20 maintained at atmospheric pressure. The aluminum substrate W was roughened. At this time, the distance between the tip of the mixing nozzle and the surface of the aluminum substrate W was 1 cm. Further, according to a confirmation with an optical microscope, the spot diameter at which the mixed plasma jet was jetted on the surface of the aluminum base was about 1000 μm. Then, after performing such a single mixed plasma jet injection, the mounting position of the aluminum substrate W on the sample stage 11 is moved so that the injection positions of the mixed plasma jet do not overlap, and the first injection position In the same manner as described above, a mixed plasma jet is ejected for 1 minute in the same manner as described above, and a total of 24 mixed plasma jets are ejected in a 5 mm × 10 mm region on the surface of the aluminum base W while repeating these steps. Thus, a roughened surface was formed to obtain a roughened aluminum base material.

  For the roughened aluminum substrate obtained above, first, using an atomic force microscope (VN-8010 manufactured by Keyence Corporation), a range of 200 μm × 200 μm was selected from the roughened surface, and AFM (Atomic When surface analysis was performed using a Force Microscope, the centerline average roughness Ra was 278.9 nm. Here, FIG. 6 shows a part of the cross section of the roughened aluminum base material, including a roughened surface, cut in the thickness direction using a scanning electron microscope (JCM-5700 manufactured by JEOL Ltd.). Is a cross-sectional SEM photograph (magnification 1000 times). As can be seen from this cross-sectional SEM photograph, in the concave portion due to the uneven portion formed by the roughening treatment, it is in the shape of a snow flake from the opening edge of the concave portion formed immediately under the plasma irradiation toward the center in the opening width direction. Projections with protruding projections (shown in (i)) or those having finer concave portions than the concave portions shown in (i) formed around the plasma irradiation [(ii )] Can be confirmed. Among these, FIG. 8 schematically shows a concave part (snow-cage holding concave part) provided with a protruding part protruding in the shape of a snow fence. And about the snow bowl holding concave part selected arbitrarily, when the maximum opening width (hole diameter) d and the height (depth) h from the deepest part to an opening edge part were measured, d = 5.5 micrometers and h = It was 6.5 μm. In the cross-sectional observation shown in FIG. 6, an adhesive was applied to the treated surface of the plasma-treated aluminum base material to produce a sample for SEM observation.

  Moreover, about the fine recessed part (ii) shown by previous FIG. 6, the SEM photograph which observed the surface of a part of roughening process surface is FIG. 7 [(a) is 1000 times magnification, (b) is (5000 times magnification). As can be seen from these SEM photographs, it can be confirmed that the roughened surface of the roughened aluminum base material was formed with uneven portions other than the snow jar-containing concave portions by the roughening treatment.

  Then, the roughened aluminum base material obtained above is set in a mold of an injection molding machine, and polyphenylene sulfide (PPS) as a thermoplastic resin (trade name manufactured by Polyplastics Co., Ltd .: Fortron, grade name RSF10719) Was used for injection molding of PPS under injection molding conditions of a mold temperature of 150 ° C., a resin temperature of 320 ° C., an injection speed of 100 mm / s, a holding pressure of 50 MPa, and a holding pressure time of 3 seconds. As shown in FIG. A PPS molded body (resin member) 41 having a size of × 10 mm × 30 mm was molded, and this PPS molded body 41 was bonded to the roughened surface (5 mm × 10 mm) of the roughened aluminum base material 42 for testing. An aluminum / resin bonded body 40 was prepared.

  With respect to the obtained test aluminum / resin bonded body 40, as shown in FIG. 10, the roughened aluminum base material 42 of the aluminum / resin bonded body 40 is fixed to a jig 44, and the upper end of the PPS molded body 41 is positioned above it. The load 43 is applied at a speed of 1 mm / min. To break the bonded portion between the roughened aluminum base material 42 and the PPS molded body 41 and the shear strength of the bonded portion of the aluminum / resin bonded body 40 is increased. The test to evaluate was implemented and the force (shear fracture load: N) when a joint was destroyed was measured. Further, the fractured surface at that time was observed, ○: when a part or most of the joint surface was broken by cohesive failure of the resin, and x: roughened aluminum base material 42 and PPS molded body 41 The bonding strength of the aluminum / resin bonded body before and after the endurance test was evaluated based on the criteria in the case of fracture at the interface. The results are shown in Table 1.

[Examples 2 to 6]
The injection time of one mixed plasma jet is 8 minutes (Example 2), 6 minutes (Example 3), 4 minutes (Example 4), 10 minutes (Example 5), and 30 minutes (Example 6). A roughened aluminum substrate was obtained in the same manner as in Example 1 except that About each obtained roughening process aluminum base material, centerline average roughness Ra of the roughening process surface was measured from the surface analysis by AFM like Example 1, and it selected arbitrarily by cross-sectional SEM observation. The maximum opening width (hole diameter) d and the height (depth) h from the deepest part to the opening edge of the concave part having snow ridges were determined. Further, with respect to the obtained roughened aluminum base material, a PPS molded body 41 was joined in the same manner as in Example 1 to produce a test aluminum / resin joined body 40, and the shear fracture load was measured. The bonding strength of the aluminum / resin bonded body was evaluated from the fracture surface at that time. The results are summarized in Table 1.

  Among these, FIG. 11 shows a photograph of the roughened aluminum substrate obtained in Example 5. The roughened surface is shown in the lower central portion of this photograph, and it can be seen that the mixed plasma jet is sprayed for 10 minutes per spot and the mixed plasma jet is sprayed to 24 spots in a 5 mm × 10 mm region.

[Comparative Example 1]
Without performing the roughening treatment by the mixed plasma jet, using the untreated aluminum base material, the PPS molded body 41 was joined in the same manner as in Example 1 to produce the test aluminum / resin joined body 40. Here, when the center line average roughness Ra of the untreated aluminum base material was measured in the same manner as in Example 1, it was 206.7 nm. Moreover, the cross-sectional observation by the cross-sectional SEM photograph was performed similarly to Example 1, but the concave part provided with the protrusion part protruded in the shape of a snow candy was not observed at all.

  Next, in order to measure the shear fracture load of the aluminum / resin bonded body 40 according to Comparative Example 1 in the same manner as in Example 1, a load 43 is applied to the untreated aluminum base material 42 fixed to the jig 44. As a result, the PPS molded body 41 was detached and the load was zero. When the joining surface in that case was confirmed, it was in the state which peeled in the interface of the untreated aluminum base material 42 and the PPS molded object 41. FIG.

[Comparative Example 2]
An aluminum base material was prepared in the same manner as in Example 1 except that helium gas was supplied to the inner tube 2 at a gas flow rate of 500 sccm without supplying the etching gas, and only the plasma jet was injected from the tip of the mixing nozzle. Roughening treatment was performed. With respect to the obtained aluminum base material, the center line average roughness Ra of the portion where only the plasma jet was injected was measured in the same manner as in Example 1. As a result, Ra was 375.0 nm. Moreover, the cross-sectional observation by the cross-sectional SEM photograph was performed similarly to Example 1, but the concave part provided with the protrusion part protruded in the shape of a snow candy was not observed at all.

  Next, for the aluminum / resin bonded body 40 according to Comparative Example 2, an attempt was made to measure the shear fracture load in the same manner as in Example 1. However, as in Comparative Example 1, the load was applied to the aluminum base material 42 fixed to the jig 44. The PPS molded body 41 was detached when 43 was applied, and the load was zero. When the joining surface at that time was confirmed, it was still in a state of peeling at the interface between the untreated aluminum base material 42 and the PPS molded body 41.

[Comparative Example 3]
The aluminum substrate was roughened in the same manner as in Example 1 except that only the etching gas was injected without generating plasma. About the obtained aluminum base material, when centerline average roughness Ra of the location which injected only the plasma jet was measured like Example 1, Ra was 210.3 nm and surface roughness was the original aluminum. It was confirmed that there was almost no change from the value of the substrate. Moreover, the cross-sectional observation by the cross-sectional SEM photograph was performed similarly to Example 1, but the concave part provided with the protrusion part protruded in the shape of a snow candy was not observed at all.

  Next, for the aluminum / resin bonded body 40 according to Comparative Example 3, an attempt was made to measure the shear fracture load in the same manner as in Example 1. However, as in Comparative Example 1, the load was applied to the aluminum base material 42 fixed to the jig 44. The PPS molded body 41 was detached when 43 was applied, and the load was zero. When the joining surface at that time was confirmed, it was still in a state of peeling at the interface between the untreated aluminum base material 42 and the PPS molded body 41.

  Based on the results of Examples 1 to 6 and Comparative Example 1 obtained above, the injection time per one time of the mixed plasma jet obtained by mixing the etching gas and the plasma jet and the aluminum base material after the roughening treatment FIG. 12 is a graph showing the relationship with the surface roughness Ra. As can be seen from the graph of FIG. 12, the surface roughness Ra of the aluminum base material increases in proportion to the increase in the injection time of the mixed plasma jet. The roughening treatment speed calculated from this result was about 34 nm / min.

  Furthermore, FIG. 13A shows an optical microscope photograph of a part of the roughened surface of the roughened aluminum substrate obtained in Example 5 observed with an optical microscope with a magnification of 200 times. Further, FIG. 13B shows the AFM measurement result obtained by selecting the range of 200 μm × 200 μm from the roughened surface of the roughened aluminum base material obtained in Example 5 and analyzing the surface with an atomic force microscope. . In addition, for comparison and reference, the same optical micrographs and AFM measurement results for the untreated aluminum substrate of Comparative Example 1 are shown in FIGS. 14A and 14B, and Comparative Example 2 is used. 15A and 15B show similar optical micrographs and AFM measurement results for the aluminum substrate on which only the helium plasma jet was injected.

Among these, as is clear from comparison between the AFM measurement results of FIGS. 14B and 15B and the AFM measurement result of FIG. 13B, an etching gas containing HCl gas and H ₂ O gas. It can be seen that the surface roughness of the aluminum base material is greatly improved by using a mixed plasma jet obtained by mixing the plasma jet and the plasma jet. Here, even in the case of Comparative Example 2 in which only the helium plasma jet was injected, the surface roughness Ra was increased as compared with the untreated aluminum substrate in Comparative Example 1, but this was caused by the plasma jet in the atmosphere. Oxygen and moisture act on the surface to oxidize the surface of the aluminum base material, and the oxide crystal may be formed or may be roughened by detachment. In Comparative here is not attached an optical micrograph and AFM measurements, without generating a plasma, was laden etching gas and HCl gas and the H ₂ O gas blowing directly to the aluminum substrate for 10 minutes Example In the case of 3, no change was observed on the surface of the aluminum substrate.

1: Outer tube of mixing nozzle, 1a: Connection port, 2: Inner tube of mixing nozzle, 3: Electrode, 10: Plasma generator, 11: Sample stage, 20: Chamber for processing, 30: Etching gas supply device, 40: Aluminum Resin bonded body, 41: PPS molded body (resin member), 42: roughened aluminum base material, 43: load, 44: jig, W: aluminum base material.

Claims (11)

A method for producing an aluminum / resin joined body in which an aluminum base material made of aluminum or an aluminum alloy and a resin member made of a thermoplastic resin are joined,
An etching gas containing gas molecules containing chlorine atoms and water molecules is mixed with a plasma jet,
The resulting mixed plasma jet is jetted onto an aluminum substrate to roughen part or all of the surface of the aluminum substrate,
The thermoplastic resin is allowed to enter and solidify into a plurality of concave portions due to the uneven portions of the aluminum base material formed by the roughening treatment, and the aluminum base material and the resin member are joined by forming a fitting portion of the resin member. A method for producing an aluminum / resin bonded body, characterized in that an aluminum / resin bonded body is obtained.   Etching gas ejected from the outer tube side of the tip of the mixing nozzle having a coaxial double tube structure of the outer tube and inner tube is mixed in the downflow region with the plasma jet ejected from the inner tube side of the tip The method for producing an aluminum / resin bonded body according to claim 1, wherein a plasma jet is obtained.   The method for producing an aluminum / resin bonded body according to claim 1, wherein the mixed plasma jet is an atmospheric pressure plasma jet.   The method for producing an aluminum / resin bonded body according to any one of claims 1 to 3, wherein the etching gas contains HCl vaporized by heating hydrochloric acid and water molecules.   In the aluminum base material, in a part or all of the plurality of concave portions, a protruding portion is formed that protrudes in the shape of a snow flake from a part or the whole of the opening edge of the concave portion toward the center in the opening width direction. The method for producing an aluminum / resin bonded body according to any one of claims 1 to 4, wherein the protruding portion forms a locking structure in which the concave portion of the aluminum base and the insertion portion of the resin member cannot be detached from each other.   When the aluminum base material is viewed in a longitudinal section cut in the thickness direction, the concave portion having a protrusion protruding in a snow candy shape has a maximum opening width of 1 μm to 100 μm, and from the deepest portion to the opening edge. The method for producing an aluminum / resin bonded body according to claim 5, wherein the height is 1 μm or more and 100 μm or less.   The unevenness part of the aluminum base material formed by the roughening treatment has a surface roughness Ra when measured by AFM of 200 nm or more and 2000 nm or less. Method. An aluminum / resin joined body in which an aluminum base material made of aluminum or an aluminum alloy and a resin member made of a thermoplastic resin are joined,
Part or all of the surface of the aluminum base material is roughened with a mixed plasma jet obtained by mixing an etching gas containing gas molecules containing chlorine atoms and water molecules with a plasma jet,
Insertion portions of a resin member into which a thermoplastic resin has entered and solidified are formed in a plurality of concave portions due to the uneven portions of the aluminum base material formed by the roughening treatment, and the aluminum base material is formed by the concave portions and the insertion portions. An aluminum / resin bonded body wherein the resin member and the resin member are locked together.   In the aluminum base material, in a part or all of the plurality of concave portions, a protruding portion is formed that protrudes in the shape of a snow flake from a part or the whole of the opening edge of the concave portion toward the center in the opening width direction. 9. The aluminum / resin bonded body according to claim 8, wherein the protruding portion forms a locking structure in which the concave portion of the aluminum base and the insertion portion of the resin member cannot be detached from each other.   When the aluminum base material is viewed in a longitudinal section cut in the thickness direction, the concave portion having a protrusion protruding in a snow candy shape has a maximum opening width of 1 μm to 100 μm, and from the deepest portion to the opening edge. The aluminum / resin bonded body according to claim 9, wherein the height is 1 μm or more and 100 μm or less.   11. The aluminum / resin bonded body according to claim 8, wherein the unevenness portion of the aluminum base material formed by the roughening treatment has a surface roughness Ra of 200 nm to 2000 nm when measured by AFM.