JP6017675B2 - Metal-resin bonded body and manufacturing method thereof - Google Patents

Description

  The present invention relates to a metal resin joined body in which a metal base material made of metal and a resin molded body made of a thermoplastic resin are integrally and firmly joined by injection molding or thermocompression bonding of a thermoplastic resin, and a method for manufacturing the same. .

  In recent years, in the fields of various sensor parts of automobiles, home appliance parts, industrial equipment parts, etc., copper base materials made of copper or copper alloy with extremely high heat dissipation and conductivity, heat dissipation, and other metals Compared to the above, a wide range of metal-resin joints are used in which an aluminum base material made of lightweight aluminum or an aluminum alloy and a resin molded body made of a thermoplastic resin, which has high insulation performance, is lightweight, and inexpensive, are integrally joined. In addition, its uses are expanding.

  Conventionally, as a metal resin bonded body in which a metal base material and a resin molded body, which are different materials, are integrally bonded to each other, an adhesive is added between the metal base material and the resin molded body. What was joined under pressure was used. However, in recent years, as an industrially more suitable joining method, a metal base material is inserted into an injection mold, and a molten thermoplastic resin is injected toward the surface of the inserted metal base material, so that thermoplasticity is achieved. A method of joining a metal substrate and a resin molded body at the same time when molding a resin molded body by injection molding of resin has been developed. Several methods for improving the bonding strength have been proposed. And many of such proposals are to perform an appropriate surface treatment on the surface of the metal substrate.

  For example, the present inventors have already made an aluminum / resin injection integrated molded product in which an aluminum shaped body and a resin molded body are already locked together by a concave portion of an aluminum material and a fitting portion of a thermoplastic resin. (Patent Document 1) and an aluminum alloy member excellent in resin bondability characterized by having a convex portion made of silicon crystal (Patent Document 2).

  In addition, for example, a technique for integrating an aluminum alloy material and a thermoplastic resin composition obtained through a pretreatment immersed in one or more aqueous solutions selected from ammonia, hydrazine, and a water-soluble amine compound by injection molding (Patent Documents 3 and 4), an aqueous solution of triazine dithiols, or a solution using various organic solvents as a solvent is used as an electrodeposition solution, and after the electrochemical surface treatment of the metal, the metal after the surface treatment (Patent Document 5) that joins rubber and plastic has been proposed. Further, an adhesive is applied on a metal plate, or an organic film is formed by surface treatment, and then injection molding is performed. Technology for integrating metal and resin (Patent Document 6), or treating the surface of the metal with acid or alkali, then treating with a silane coupling agent, and then injection molding resin Bonded to technology (Patent Document 7) it has been proposed respectively.

  Furthermore, a technique for injecting a thermoplastic resin onto the surface of a metal on which a microporous hydroxyl group-containing film is formed and integrating the metal and the thermoplastic resin through the film (Patent Document 8), or polyarylene A technique (Patent Document 9) has been proposed in which a metal terminal or the like is inserted and joined using a resin material mainly composed of a sulfide resin and a specific olefin copolymer and an inorganic filler blended therein.

WO2009-151,099 publication JP 2010-174,372 Japanese Patent No. 3,954,379 Japanese Patent No. 4,270,444 Japanese Patent Publication No. 05-051,671 Japanese Patent No. 3,016,331 JP2003-103,562 Japanese Patent Laid-Open No. 2008-162,115 JP 04-211,916

  Here, in the methods using ammonia, hydrazine, and water-soluble amine compounds described in Patent Documents 3 and 4, there is a limit on the time from the treatment to the injection molding, so the time for maintaining a stable surface state There is a problem that is short. Further, the processing method described in Patent Document 5 has a problem that the processing is complicated, and the methods described in Patent Documents 6 and 7 have a problem that the process is complicated and the processing cost is high. .

  By the way, as described in Patent Document 1 and Patent Document 2, the present inventors have so far proposed a physical bonding mainly based on the fitting of the anchor effect, and a special treatment in which halogen ions are contained in the treatment bath as the technique. A method by a simple etching process has been proposed. Although these methods have no problem in performance such as bonding strength and airtightness of the bonded portion, gas derived from halogen is generated during this etching process, and the surrounding metal parts and equipment are not corroded. There was another issue of having to take measures to prevent polluting the environment.

  Patent Document 8 describes the anchor effect and chemical action of a porous hydroxyl group-containing film, and the effect of using a thermoplastic resin composition to which a thermoplastic elastomer is added. Patent Document 9 discloses polyarylene sulfide resin. However, it is not clear about the effect on the bonding strength and adhesion by combining the metal surface treatment and the functional group of the resin composition. there were.

  Therefore, the present inventors have no problem with surrounding equipment and environment when joining between the metal substrate and the resin molded body made of thermoplastic resin, and are simple operation, low cost, and long-term. As a result of extensive studies to develop a method that can achieve excellent bonding strength, an oxygen-containing film containing oxygen is formed on the surface of a metal substrate by intentionally increasing the oxygen content. When joining a resin molded body formed of a thermoplastic resin composition on the oxygen-containing film, an additive compound having a specific functional group that reacts with the oxygen-containing film is added to the thermoplastic resin composition. By performing injection molding or thermocompression bonding (metal-resin bonding) between the metal base material and the resin molded body, a long period of time is present between the oxygen-containing film on the surface of the metal base material and the resin molded body. A strong bond can be formed over Headlines, and completed the present invention.

  Accordingly, an object of the present invention is to provide a metal-resin joint that exhibits excellent metal-resin bond strength and that does not cause a decrease in strength after a durability test, and that can maintain excellent metal-resin bond strength over a long period of time. To provide a body.

That is, the present invention includes a metal substrate made of metal, an oxygen-containing film containing oxygen formed by intentionally increasing the oxygen content on the surface of the metal substrate, and the oxygen-containing film. A resin molded body joined on the film and formed of a thermoplastic resin composition;
The thermoplastic resin composition contains an additive compound having a functional group that reacts with an oxygen-containing film,
The additive compound is selected from the group consisting of carboxyl groups and salts thereof and esters thereof, epoxy groups, glycidyl groups, isocyanate groups, carbodiimide groups, amino groups and salts thereof, and acid anhydride groups and esters thereof. At least 1
Has a kind of functional group ,
The metal resin joined body is characterized in that the functional group of the additive compound is contained in the thermoplastic resin composition at a rate of 0.5 to 150 μmol / g .

Also, a film forming step for forming an oxygen-containing film by intentionally increasing the oxygen content on the surface of a metal base material made of metal, and a surface-treated metal substrate obtained in this film forming step A resin molding step of forming a resin molded body by injection molding of a thermoplastic resin composition on the oxygen-containing film of
It is a method for producing a metal resin joined body for producing a metal resin joined body in which a metal substrate and a resin molded body are joined through the oxygen-containing film,
The thermoplastic resin composition contains an additive compound having a functional group that reacts with an oxygen-containing film, and the additive compound comprises a carboxyl group and a salt thereof and an ester thereof, an epoxy group, a glycidyl group, an isocyanate group, and a carbodiimide. It is a method for producing a gold resin joined body having at least one functional group selected from the group consisting of a group, an amino group and a salt thereof, and an acid anhydride group and an ester thereof.

Furthermore, with respect to the metal resin bonded body of the present invention , a film forming step of forming an oxygen-containing film by intentionally increasing the oxygen content on the surface of a metal base material made of metal, and a thermoplastic resin A resin molding step obtained by the resin molding step on a resin molding step of forming a resin molding by injection molding of the composition, and an oxygen-containing coating of the surface-treated metal base obtained by the coating step. And a metal resin bonding process for bonding by injection molding or thermocompression bonding,
As the thermoplastic resin composition contains an additive compound having a functional group that reacts with oxygen-containing coating, and the additive compound is a carboxyl group and its salts and esters thereof, epoxy group, glycidyl group, isocyanate group, Producing also by a method using a thermoplastic resin composition which is a compound having at least one functional group selected from the group consisting of a carbodiimide group, an amino group and a salt thereof, and an acid anhydride group and an ester thereof. Can do .

  In the present invention, the metal base material used as a base is particularly limited, such as a copper base material made of copper or a copper alloy, an iron base material made of iron or an iron alloy, an aluminum base material made of aluminum or an aluminum alloy, or the like. However, it can be determined on the basis of various physical properties such as strength, corrosion resistance, and workability required for the use of the metal-resin bonded body formed by using the metal-resin bonded body. The material and shape of the aluminum base material are not particularly limited as long as it is made of aluminum or an aluminum alloy, and the strength required for the use of the aluminum resin joined body formed using the aluminum base material. It can be determined based on various physical properties such as corrosion resistance and workability.

  Further, the oxygen-containing film formed on the surface of such a metal substrate is not particularly limited as long as the adhesion with the metal substrate is good, but the metal substrate is copper. In the case of a substrate, for example, an oxygen-containing film obtained by blackening treatment or an oxygen-containing film (thermal oxide film) obtained by laser treatment can be exemplified, and the metal substrate is iron-based. In the case of a material, for example, an oxygen-containing film derived from a zinc film obtained by galvanizing treatment can be mentioned. Furthermore, when the metal substrate is an aluminum substrate, a zinc ion-containing alkaline aqueous solution is used. A zinc-containing film containing zinc element obtained by the film forming process used, a film forming process using hot water of 91 ° C. or higher and 100 ° C. or lower, or a film using hot water of 60 ° C. or higher and 90 ° C. or lower Hydrated oxide film obtained by the formation process, It can be exemplified obtained oxide film or the like on the surface of the lumi substrate with a film forming process for performing laser processing.

  Here, regarding the film formation treatment for forming the zinc-containing film containing zinc element as the oxygen-containing film on the surface of the aluminum base material, the surface of the aluminum base material is oxidized with zinc oxide (ZnO) and oxidized with the zinc element. It is only necessary to be able to form a coating containing zinc iron (ZnFeO), zinc oxide aluminum (ZnAlO), etc., and when molding a resin molded body by injection molding of a thermoplastic resin composition, this thermoplasticity By thermocompression bonding with a resin molded body obtained by molding the resin composition, a strong aluminum-resin bonding strength is achieved between the resin molded body formed on the oxygen-containing film.

Then, the film-forming process using the zinc ion containing aqueous alkali solution, preferably an alkali hydroxide (MOH) and zinc ion (Zn ²⁺⁾ in a weight ratio (MOH / Zn ²⁺⁾ ratio of 1 to 100 inclusive By using a zinc ion-containing aqueous alkali solution that is preferably contained in a proportion of 2 or more and 20 or less, more preferably 3 or more and 10 or less, the zinc ion-containing alkaline aqueous solution is brought into contact with the surface of the aluminum substrate at room temperature, thereby producing aluminum. A zinc-containing film containing oxygen is preferably formed on the surface of the substrate. If the weight ratio (MOH / Zn ²⁺ ) between the alkali hydroxide (MOH) and zinc ions (Zn ²⁺ ) is less than 1 (MOH <Zn ²⁺ ), the effect of the zinc is not sufficiently dissolved. On the other hand, if it is larger than 100 (MOH> 100 Zn ²⁺ ), the dissolution of the aluminum base becomes faster than the substitutional precipitation of zinc, and zinc does not easily precipitate on the surface of the aluminum base.

  Here, with respect to the alkali source in the zinc ion-containing alkaline aqueous solution, preferably one or more selected from sodium hydroxide, potassium hydroxide, and lithium hydroxide is used, and this zinc ion-containing alkaline aqueous solution is used. The zinc ion source is preferably at least one selected from zinc oxide, zinc hydroxide, zinc peroxide, zinc chloride, zinc sulfate, and zinc nitrate.

  In this zinc ion-containing aqueous alkali solution, the alkali hydroxide concentration is 10 g / L or more and 1000 g / L or less, preferably 50 g / L or more and 300 g / L or less. It may be 1 g / L or more and 200 g / L or less, preferably 10 g / L or more and 100 g / L or less. By making the composition of the aqueous solution containing zinc ions within the above range, aluminum and zinc ions cause a substitution reaction on the surface of the aluminum base material, aluminum is dissolved, and zinc ions are precipitated as fine particles, As a result, an oxygen-containing film (zinc-containing film) containing an oxygen element and a zinc element is formed on the surface of the aluminum substrate. That is, aluminum melts while forming a concave portion, and zinc is precipitated in the concave portion to form a zinc-containing film containing zinc element. Here, when the alkali hydroxide concentration is less than 10 g / L, there is a problem that the formation of a zinc-containing film containing zinc element becomes insufficient. On the other hand, when the alkali hydroxide concentration exceeds 1000 g / L, the dissolution rate of aluminum by alkali is high. There arises a problem that a zinc-containing film containing zinc element is not formed. In addition, when the zinc ion concentration is less than 1 g / L, there is a problem that it takes time to form a zinc-containing film. Conversely, when the zinc ion concentration exceeds 200 g / L, the zinc deposition rate cannot be controlled and the surface becomes uneven. Arise.

  Regarding the film formation treatment for forming a hydrated oxide film as an oxygen-containing film on the surface of the aluminum substrate, first, the electrical conductivity is 0.01 mS / m or more and 20 mS / m or less, preferably 0.01 mS / m. m hot water of not less than 10 mS / m and not less than 91 ° C. and not more than 100 ° C. The aluminum substrate is usually immersed in this hot water for not less than 0.5 minutes and not more than 30 minutes, preferably not less than 1 minute and not more than 10 minutes. To form a hydrated oxide film, or hot water having an electrical conductivity of 0.01 mS / m to 20 mS / m, preferably 0.01 mS / m to 10 mS / m, and 60 ° C. to 90 ° C. In this hot water, the aluminum substrate is usually immersed for 0.5 minutes to 30 minutes, preferably 1 minute to 10 minutes to form a hydrated oxide film. It is preferable that the hot water or hot water used in the film forming treatment for forming the hydrated oxide film is pure water. If the electrical conductivity of hot water or hot water used in the film formation process for forming this hydrated oxide film is less than 0.01 mS / m, it will be in the region of ultrapure water, resulting in high production costs of pure water. On the other hand, when it exceeds 20 mS / m, the hydrated oxide film may not be formed, and the film formation rate becomes extremely slow, and the presence of impurities. There is also a problem that film defects of the hydrated film easily occur.

  The hydrated oxide film formed on the surface of the aluminum base material was confirmed by X-ray diffraction. As a result, it was confirmed that boehmite or pseudoboehmite (boehmite) or pseudoboehmite ( This is a film with a broad peak mainly composed of pseudoboehmite), and in the film formation treatment using hot water of 60 ° C. or more and 90 ° C. or less, the peak derived from the crystalline component is not mainly observed. It is a film mainly composed of (amorphous).

  The X-ray diffraction measurement of the hydrated oxide film was performed by measuring 30 mm × from the surface-treated aluminum base material after the hydrated oxide film was formed as the oxygen-containing film on the surface of the aluminum base material by the film forming process. A sample for measurement was prepared with a thickness of 30 mm, and this sample was fixed to a glass sample plate (sample part 24 mm square / penetration) of an X-ray diffraction apparatus [manufactured by Rigaku Corporation: RAD-rR]. Cu rotating anti-cathode target (used X-ray and wavelength: CuKα 1.5418 mm), X-ray output: 50 kV, 200 mA, detector: scintillation detector, optical system attributes: Bragg-Brentano optical system (concentrated method), diverging slit 1 ° , Measured under conditions of a scattering slit of 1 ° and a light receiving slit of 0.3 mm, the contained components are identified, and then, among the peaks representing each detected phase, the peaks are high in intensity and derived from other components Integral diffraction intensity for one non-overlapping peak Calculated and determined.

Furthermore, with respect to the laser treatment for forming an oxide film as an oxygen-containing film on the surface of the aluminum substrate performed in the film forming step, the vicinity of the surface of the aluminum substrate, preferably only the vicinity of the surface, is partially made of aluminum. Heating to above the melting temperature of the base material to oxidize and deposit aluminum oxide (Al ₂ O ₃ ) near the surface of the aluminum base material to form an oxygen-containing film containing this aluminum oxide (Al ₂ O ₃ ) For example, a laser etching apparatus or the like can be used.

  The surface-treated aluminum base material obtained by forming the oxygen-containing film on the surface of the aluminum base material in the above-described film forming step is measured by EPMA on the surface layer from the outermost surface to a depth of 3 μm. The oxygen content is 0.1 to 50% by weight, preferably 1.0 to 30% by weight. When the oxygen content in the surface layer of this surface-treated aluminum base material is lower than 0.1% by weight, the coating is too thin to achieve sufficient aluminum-resin bonding strength between the aluminum base material and the resin molding. On the other hand, if the oxygen content is higher than 50% by weight, the film is too thick, causing cohesive failure of the film, and sufficient aluminum-resin bonding strength cannot be obtained. .

  In addition, the thickness of the oxygen-containing film formed on the surface of the aluminum substrate in this film forming process is usually 0.06 μm or more and 2 μm or less, preferably 0.1 μm or more and 1 μm or less. Good. If the film thickness of the oxygen-containing film is less than 0.06 μm, the film may be too thin to obtain sufficient aluminum-resin bonding strength. Conversely, if the film thickness exceeds 2 μm, the film will be thick. Thus, cohesive failure of the film may occur, and sufficient aluminum-resin bonding strength may not be obtained.

  The thickness of the hydrated oxide film formed on the surface of the aluminum base material by the film forming process using hot water of 91 ° C. or higher and 100 ° C. or lower is usually 0.1 μm or more and 1 μm or less. The thickness is preferably 0.2 μm or more and 0.5 μm or less. If the film thickness of this oxygen-containing film is less than 0.1 μm, the film may be too thin to obtain sufficient aluminum-resin bonding strength. Conversely, if the film thickness exceeds 1 μm, the film will be thick. Thus, cohesive failure of the film may occur, and sufficient aluminum-resin bonding strength may not be obtained.

  In addition, the thickness of the hydrated oxide film formed on the surface of the aluminum substrate by the film forming process using hot water of 60 ° C. or more and 90 ° C. or less is usually 0.1 μm or more and 1 μm or less. The thickness is preferably 0.2 μm or more and 0.5 μm or less. If the film thickness of this oxygen-containing film is less than 0.1 μm, the film may be too thin to obtain sufficient aluminum-resin bonding strength. Conversely, if it exceeds 1 μm, the film will be thick. Thus, cohesive failure of the film may occur, and sufficient aluminum-resin bonding strength may not be obtained.

  In the present invention, for the surface-treated aluminum base material having an oxygen-containing film on the surface obtained in the film forming step, the resin molded body is integrated on the oxygen-containing film by injection molding of a thermoplastic resin composition. The resin molding process for forming the resin molded body by injection molding of the thermoplastic resin composition, and the obtained resin molded body with the surface-treated aluminum base. Aluminum that is integrally bonded by thermocompression using means such as laser welding, vibration welding, ultrasonic welding, hot press welding, hot plate welding, non-contact hot plate welding, or high frequency welding on the oxygen-containing film of the material. An aluminum resin bonded body is manufactured by a resin bonding process.

  In the present invention, the thermoplastic resin composition used in the above resin molding step specifically includes a sulfur element such as a polyarylene sulfide resin such as polyphenylene sulfide (PPS) or a sulfone resin. Resins such as polyester resins such as polybutylene terephthalate (PBT), resins containing oxygen atoms such as liquid crystal polymers, polycarbonate resins, polyacetal resins, polyether resins, polyphenylene ether resins, such as polyamide (PA) , ABS, polyimide, polyetherimide, and other resin compositions comprising a thermoplastic resin containing a nitrogen atom. Among them, automotive parts that have a great need for metal-resin bonded bodies are particularly preferred in terms of heat resistance and rigidity. In electrical and electronic parts, PPS, BT, liquid crystal polymer, engineering plastics such as polyacetal particularly preferred.

  Moreover, as a thermoplastic resin composition used at said resin molding process, the resin composition containing the additive compound which has a specific functional group which reacts with an oxygen-containing film | membrane is used. Here, the additive compound means a substance other than the thermoplastic resin constituting the thermoplastic resin composition, and is particularly limited as long as it is used by being added to the thermoplastic resin composition. It is not intended to be added for various purposes in consideration of the production of thermoplastic resin compositions, the moldability and processability of thermoplastic resin compositions, the properties of resin moldings obtained by molding thermoplastic resin compositions, etc. Examples include various additives such as antioxidants, mold release agents, plasticizers, UV absorbers, heat stabilizers, antistatic agents, dyes, pigments, lubricants, silane coupling agents, fillers, and elastomers. Among them, an elastomer is particularly preferable as an additive from the viewpoint of alleviating distortion between a metal and a resin caused by a difference in linear expansion.

  Here, the additive compound includes a carboxyl group and a salt thereof and an ester thereof, an epoxy group, a glycidyl group, an isocyanate group, a carbodiimide group, an amino group and a salt thereof, and an acid anhydride group and an ester thereof. A compound having at least one functional group selected from among them is preferable, and among them, a compound having a glycidyl group is particularly preferable. The additive compound is preferably an olefin copolymer containing a structural unit derived from α-olefin and a structural unit derived from a glycidyl ester of an α, β-unsaturated acid, and is further a (meth) acrylic copolymer. An olefin copolymer containing a structural unit derived from an acid ester is more preferred. Hereinafter, (meth) acrylic acid ester is also referred to as (meth) acrylate. For example, glycidyl (meth) acrylate is also referred to as glycidyl (meth) acrylate. In the present specification, “(meth) acrylic acid” means both acrylic acid and methacrylic acid, and “(meth) acrylate” means both acrylate and methacrylate.

  The α-olefin is not particularly limited, and examples thereof include ethylene, propylene, butylene, and ethylene is particularly preferable. The α-olefin can be used alone or in combination of two or more.

  When the additive compound contains a structural unit derived from α-olefin, flexibility is easily imparted to the resin molded body. By providing this flexibility, the resin molded body becomes soft, excellent metal-resin bonding strength is exhibited, and strength reduction after a durability test is prevented, and excellent metal-resin bonding strength over a long period of time. Is easily maintained.

  The glycidyl ester of α, β-unsaturated acid is not particularly limited, and examples thereof include glycidyl acrylate ester, glycidyl methacrylate ester, glycidyl ethacrylate ester, etc., and glycidyl methacrylate ester is particularly preferable. The glycidyl ester of α, β-unsaturated acid can be used alone or in combination of two or more. When the additive compound contains a glycidyl ester of α, β-unsaturated acid, an effect of improving the bonding strength between the metal and the resin can be obtained.

  The (meth) acrylic acid ester is not particularly limited. For example, methyl acrylate, ethyl acrylate, acrylic acid-n-propyl, acrylic acid isopropyl, acrylic acid-n-butyl, acrylic acid-n-hexyl, acrylic Acrylic acid esters such as acid-n-octyl; methyl methacrylate, ethyl methacrylate, -n-propyl methacrylate, isopropyl methacrylate, n-butyl methacrylate, isobutyl methacrylate, methacrylic acid-n-amyl, methacrylic acid and methacrylates such as -n-octyl. Of these, methyl acrylate is particularly preferable. The (meth) acrylic acid ester can be used alone or in combination of two or more. The structural unit derived from (meth) acrylic acid ester contributes to the improvement of the bonding strength between the metal and the resin.

  Olefin copolymer containing a structural unit derived from α-olefin and a structural unit derived from a glycidyl ester of α, β-unsaturated acid, and an olefin copolymer containing a structural unit derived from (meth) acrylic acid ester A coalescence can be manufactured by superposing | polymerizing by a conventionally well-known method. For example, the copolymer can be obtained by performing copolymerization by a well-known radical polymerization reaction. The type of the copolymer is not particularly limited. For example, the copolymer may be a random copolymer or a block copolymer. In addition, for example, polymethyl methacrylate, polymethacrylate ethyl, polymethyl acrylate, polyethyl acrylate, polybutyl acrylate, polyethyl acrylate-2-ethylhexyl, polystyrene, polyacrylonitrile, An olefin-based graft copolymer in which polyacrylonitrile / styrene copolymer, butyl acrylate / styrene copolymer, or the like is chemically bonded in a branched or cross-linked structure may be used.

  The olefin-based copolymer used in the present invention can contain structural units derived from other copolymerization components as long as the effects of the present invention are not impaired.

  The functional group of the additive compound is contained in the thermoplastic resin composition at a rate of 0.5 to 150 μmol / g, preferably 0.5 to 50 μmol / g, more preferably 2 to 25 μmol / g. The If the ratio of the functional group in the thermoplastic resin composition is lower than 0.5 μmol / g, the bonding strength between the metal and the resin tends to decrease, and conversely, if it exceeds 150 μmol / g, the characteristics as the resin material, particularly the fluidity It is not preferable because it tends to adversely affect mechanical strength such as tensile strength and bending strength, and rigidity.

  Here, the ratio of the functional group in the thermoplastic resin composition is as follows. When “Molecular weight per functional group” in the additive compound added to the thermoplastic resin composition is M, Since the amount of the functional group is 1 / M (mol / g), for example, when this additive compound is added to the thermoplastic resin composition in a proportion of 1% by mass, (1 / M) × (1/100 ) = 1/100 M (mol / g). The “molecular weight per functional group” M is ½ of the molecular weight Mw of the additive compound itself if the additive compound has a plurality of, for example, two functional groups.

  Further, in the present invention, an oxygen-containing film is formed on the entire surface of the metal base material to be a base, and resin molding is performed by injection molding only at a necessary portion of the obtained surface-treated metal base material or by thermocompression bonding. The body may be joined, or in consideration of cost, an oxygen-containing film is formed only on a part of the surface of the metal substrate or only at a necessary portion, and the obtained surface-treated metal substrate is necessary. You may join a resin molding to a location by injection molding or thermocompression bonding. And, when forming the oxygen-containing film only on a part of the surface of the metal substrate or only necessary portions, the oxygen-containing film is masked after masking portions other than the part that forms the oxygen-containing film, for example, with a masking tape or the like. A process for forming the mask may be performed, and then the masking tape or the like of the masked portion may be removed.

  In the method for producing a metal-resin bonded body according to the present invention, a pre-treatment of the surface of the metal substrate, if necessary, as a pretreatment of the surface of the metal substrate, if necessary, a degreasing treatment, an etching treatment, a desmut treatment, and a rough surface. Any one type or two or more types of processing selected from a chemical conversion treatment, a chemical polishing treatment, and an electrolytic polishing treatment may be performed.

  About the degreasing process performed as said pre-processing, it can carry out using the normal degreasing bath which consists of sodium hydroxide, sodium carbonate, sodium phosphate, surfactant, etc. As immersion conditions, immersion temperature is usually 15 The immersion time is 1 minute or more and 10 minutes or less, preferably 3 minutes or more and 6 minutes or less.

  Moreover, about the etching process performed as said pretreatment, acid aqueous solution, such as alkaline aqueous solution, such as sodium hydroxide, or a sulfuric acid-phosphoric acid mixed aqueous solution, is normally used. And when using aqueous alkali solution, the density | concentration of 20 g / L or more and 200 g / L or less is used, Preferably it is 50 g / L or more and 150 g / L or less, Immersion temperature 30 to 70 degreeC, Preferably it is 40 to 60 degreeC. The immersion treatment may be performed under a treatment condition of not more than ° C. and a treatment time of 0.5 to 5 minutes, preferably 1 to 3 minutes. When a sulfuric acid-phosphoric acid mixed aqueous solution that is an acid aqueous solution is used, the sulfuric acid concentration is 10 g / L or more and 500 g / L or less, preferably 30 g / L or more and 300 g / L or less, and the phosphoric acid concentration is 10 g / L or more and 1200 g. / L or less, preferably 30 g / L or more and 500 g / L, immersion temperature 30 ° C. or more and 110 ° C. or less, preferably 55 ° C. or more and 75 ° C. or less, and immersion time 0.5 minutes or more and 15 minutes or less, preferably The immersion treatment is preferably performed under a treatment condition of 1 minute to 6 minutes.

  Furthermore, for the desmutting treatment performed as the pretreatment, for example, a desmutting bath made of an aqueous nitric acid solution having a concentration of 1 to 30% is used, an immersion temperature of 15 ° C to 55 ° C, preferably 25 ° C to 40 ° C, and an immersion time of 1 The immersion treatment may be performed under a treatment condition of not less than 10 minutes and not more than 10 minutes, preferably not less than 3 minutes and not more than 6 minutes.

Furthermore, with regard to the roughening treatment performed as the pretreatment, for example, after the pretreatment of the aluminum base material, in the treatment liquid mainly composed of ammonium acid fluoride (trade name: JCB-3712 manufactured by Nippon Sea Hey Chemical) The method etc. which are immersed in can be illustrated. By this treatment, it is possible to dissolve and remove the Al material containing Si in the alloy without leaving the Si, so that even if an oxygen-containing film is subsequently applied, no problems such as defects occur, and it is good. It is possible to obtain a high bonding strength.
In addition, a conventionally well-known method is employable about the chemical polishing process and electropolishing process performed as said pre-processing.

  The principle of bonding between the metal substrate and the resin molded body in the present invention is still unclear, but the oxygen-containing film formed on the surface of the metal substrate after bonding between the metal substrate and the resin molded body Remains without being destroyed, and from the following verification results, it is generally considered as follows.

For example, when the metal is an aluminum substrate, a plurality of surface-treated aluminum substrates having an oxygen-containing film are formed on the surface of the aluminum substrate, and some of the surface-treated aluminum substrates have a glycidyl group on the surface. The PPS molded body was joined by injection molding of polyphenylene sulfide (PPS) having an aluminum PPS joined body. For the remaining surface-treated aluminum substrate, first, stearic acid is volatilized in an electric furnace maintained at 100 ° C., and the surface-treated aluminum substrate is exposed therein for 24 hours. A stearic acid-treated aluminum base material having a monomolecular film of stearic acid, and a PPS molded body is joined to the surface of the stearic acid-treated aluminum base material by injection molding of PPS having a glycidyl group, thereby stearic acid-treated aluminum PPS joining. The body.
The difference in bonding strength between the aluminum PPS bonded body and the stearic acid-treated aluminum PPS bonded body was measured. As a result, the bonding strength in the stearinized aluminum PPS bonded body is the bonding strength of the aluminum PPS bonded body. Compared with, it was clearly reduced.

Stearic acid has both a carboxyl group (COOH) which is a hydrophilic group and an alkyl group (C ₁₇ H ₃₅ ) which is a hydrophobic group, and has a property of forming a monomolecular film having a thickness of one molecule. In a stearic acid-treated aluminum PPS bonded body, the oxygen-containing film of the aluminum base and the carboxyl group side of stearic acid are chemically bonded, and the alkyl group side comes into contact with the PPS molded body. It is considered that the chemical bond between the base material and the PPS molded body is inhibited, and the bonding strength is lower than the bonding strength of the aluminum PPS bonded body.

  Further, the surface-treated aluminum base material before and after the stearic acid treatment was compared and examined by observing the surface, but no difference was found in the surface structure depending on the presence or absence of the stearic acid monomolecular film. On the other hand, when the surface-treated aluminum base material after the stearic acid treatment was dropped and the contact angle was measured, the contact angle was close to 180 °, and the droplet was almost spherical. This is a result of supporting that the alkyl group side of stearic acid is unevenly distributed on the outermost layer side of the aluminum base material.

  From the above, between the surface-treated metal substrate in the metal resin bonded body of the present invention and the resin molded body having a glycidyl group, there is a chemical bond between oxygen of the oxygen-containing film and the glycidyl group in the resin. It is considered that this chemical bond action exerts an effect of increasing the bonding strength between the metal substrate and the resin molded body.

  The metal-resin bonded body of the present invention is a specific material in which the surface of a metal substrate is coated with an oxygen-containing film by intentionally increasing the oxygen content and reacts with the oxygen-containing film as a thermoplastic composition. By using a resin composition containing an additive compound having a functional group of, by injection molding of this thermoplastic resin composition, or by thermocompression bonding of a resin molded body obtained by injection molding of this thermoplastic resin composition It is obtained by joining a resin molded body on the oxygen-containing film on the surface of the metal substrate, and the metal substrate and the resin molded body are not only firmly bonded via the oxygen-containing film, but also for a long time. Thus, excellent metal-resin bonding strength can be maintained.

  Further, according to the method for producing a metal-resin joined body of the present invention, in the film formation step of forming an oxygen-containing film by intentionally increasing the oxygen content on the surface of the metal substrate, gas generation, etc. In addition, it is possible to operate at room temperature, there is no problem with surrounding equipment and environment, simple operation and low cost, metal-resin bonding that can exhibit excellent metal-resin bonding strength over a long period of time The body can be manufactured.

FIG. 1 is an explanatory view for explaining a metal resin bonded body produced in Example 1 of the present invention. FIG. 2 is an explanatory diagram for explaining a method of an evaluation test of the bonding strength between the metal and the resin carried out in Example 1 of the present invention.

Hereinafter, based on an Example and a comparative example, the metal resin joined body of this invention and its manufacturing method are demonstrated concretely.
1. In the following Examples and Comparative Examples, the surface roughening treatment and the film formation treatment for forming the oxygen-containing film performed as pretreatment are as follows.

(Roughening treatment)
First, as a pretreatment, the aluminum substrate was immersed in an aqueous nitric acid solution adjusted to 30% by mass at room temperature for 0.5 minutes, and then 50 ° C. in an aqueous sodium hydroxide solution adjusted to 5% by mass, After dipping for 0.5 minutes and further dipping in an aqueous nitric acid solution adjusted to 30% by weight at room temperature for 0.5 minutes, the pretreated aluminum substrate was then adjusted to a concentration of 20% by weight. A roughened aluminum base material was prepared by immersing in a treatment liquid (JCB-3712, manufactured by Nippon CB Chemical Co., Ltd.) containing adjusted acidic ammonium fluoride as a main component at a temperature of 40 ° C. for 10 minutes.

[Film formation treatment of oxygen-containing film]
(1) Treatment method A (Formation of zinc-containing film)
Zinc ion-containing aqueous solution of sodium of (NaOH-Zn ²⁺ solution) was prepared (20 g / L as Zn ²⁺⁾ sodium hydroxide as a film-forming treatment agent concentration 100 g / L and the zinc oxide concentration 25 g / L. Next, the aluminum base material was immersed in this zinc ion-containing sodium aqueous solution for 1 minute at room temperature (Note: only in the case of Comparative Example 1 was immersed for 5 minutes), then washed with water, and an oxygen-containing film on the surface. As a test, a surface-treated aluminum base material for testing on which a zinc-containing film containing zinc element was formed was prepared.

(2) Treatment method B (formation of hydrated oxide film by hot water)
A test in which an aluminum substrate is immersed in hot water (pure water) at 91 to 100 ° C. for 0.5 to 30 minutes, and a hydrated oxide film mainly composed of boehmite or pseudoboehmite is formed on the surface as an oxygen-containing film. A surface-treated aluminum substrate was prepared.

(3) Treatment method C (formation of hydrated oxide film by hot water)
An aluminum base material was used in the same manner as in the treatment method B (formation of a hydrated oxide film by hot water) except that hot water (pure water) at a temperature of 60 to 80 ° C. was used and the immersion time was changed to 1 to 5 minutes. A surface-treated aluminum base material for testing, in which a hydrated oxide film mainly composed of an amorphous component was formed as an oxygen-containing film on the surface, was prepared.

(4) Treatment method D (formation of oxide film by laser treatment)
In the laser etching process (device name: Miyachi Technos / ML-7112A; laser wavelength: 1064 nm, spot diameter: 50-60 μm, oscillation method: Q switch pulse, frequency: 10 kHz), the pitch width is 50 μm intervals on the surface of the aluminum substrate. Were subjected to laser irradiation in the same direction to produce a surface-treated aluminum base material for test in which an oxide film (Al ₂ O ₃ ) was formed as an oxygen-containing film on the surface of the aluminum base material.

2. In the following Examples and Comparative Examples, the resin species and additive compounds in the resin compositions used are as follows.
[Resin species in the resin composition]
PPS (1): PPS resin composition [trade name: Durafide (registered trademark) RSF-10719 manufactured by Polyplastics Co., Ltd .; additive compounds a and b described later; and inorganic filler 50%. ]
PPS (2): PPS resin [trade name: Fortron KPS W203A manufactured by Kureha Co., Ltd. {melt viscosity: 30 Pa · s (shear rate: 1216 sec ⁻¹ , 310 ° C.)}]
PBT: PBT resin [Wintech Polymer Co., Ltd. trade name: TRB-CP]
PP: PP resin composition (trade name: R-350G, manufactured by Prime Polymer Co., Ltd.)
POM: POM resin (polyacetal copolymer obtained by copolymerizing 96.7% by mass of trioxane and 3.3% by mass of 1,3-dioxolane, melt index (measured at 190 ° C. and a load of 2160 g): 9g / 10min]
LCP: Aromatic polyester liquid crystal resin (melting point: 280 ° C, melt viscosity (300 ° C): 50.1 Pa · s)

The above aromatic polyester liquid crystal resin (LCP) is manufactured as follows.
Using a reactor equipped with a stirrer, a distillation pipe, a gas introduction pipe, a discharge hole, etc., p-hydroxybenzoic acid 345 parts by weight (73 mol%), 6-hydroxy-2-naphthoic acid 175 parts by weight (27 mol%), 0.02 part by weight of potassium acetate and 350 parts by weight of acetic anhydride were charged into the reactor, and the reactor was sufficiently replaced with nitrogen. Then, the temperature was raised to 150 ° C. under normal pressure, and stirring was started. The mixture was stirred at 150 ° C. for 30 minutes, and the temperature was gradually raised, and acetic acid produced as a by-product was distilled off. When the temperature reaches 300 ° C, the pressure inside the reactor is gradually reduced, and stirring is continued for 1 hour at a pressure of 5 Torr (ie, 665 Pa). When the target stirring torque is reached, a discharge hole is opened at the bottom of the reactor. The resin produced using nitrogen pressure was extruded into a strand shape and taken out. The taken-out strand was shaped into particles with a pelletizer.

[Additive compound in resin composition]
Additive Compound a: Glycidyl group-containing elastomer [trade name: Modiper A4300, manufactured by NOF Corporation]
Additive compound b: Elastomer not containing functional group [Dow Chemical Japan Co., Ltd. trade name: Engage 8440]
Additive compound c: Elastomer containing glycidyl group [trade name: Bondfast 7L, manufactured by Sumitomo Chemical Co., Ltd.]
Additive compound d: isocyanate compound [Degussa Japan Co., Ltd. product name: Vestanat T1890 / 100]
Additive compound e: Epoxy compound [Mitsubishi Chemical Corporation product name: Epicoat JER1004K]
Additive compound f: Ester elastomer [trade name: NUC-6570, manufactured by Nippon Unicar Co., Ltd.]
Additive Compound g: Dicyandiamide [Nippon Carbide Industries, Ltd., trade name: Dicyandiamide G]
Additive compound h: Carbodiimide compound [Rhein Chemie Japan Co., Ltd. trade name: Stavacsol P400]
Additive compound i: Glycidyl group-containing elastomer (trade name: Bond First E, manufactured by Sumitomo Chemical Co., Ltd.)

3. In the following examples and comparative examples, the “oxygen content” and “film thickness” of the oxygen-containing film formed on the surface of the aluminum substrate and the “film thickness of the aluminum resin joined body” are as follows: And measured.
[Measurement of oxygen content of oxygen-containing film]
The surface-treated aluminum base material obtained in the manufacturing process of the aluminum resin joined body was subjected to mapping analysis using EPMA (manufactured by Shimadzu: EPMA 1610) and measuring 512 steps in the vertical and horizontal directions at an irradiation diameter of 40 μm / step. Here, the measurement area is 20.48 mm × 20.48 mm, the sampling time for one step is 20 ms, the acceleration voltage is 15 kV, and the resolution in the depth direction of oxygen is 3 μm or less. Next, the detected oxygen intensity was calculated as a weight percentage (wt%) from a calibration curve prepared in advance. The calibration curve used was calculated and prepared from two points: the oxygen intensity of the Al ₂ O ₃ standard sample (oxygen content: 48 wt%) and the oxygen intensity of the high-purity Al foil.

[Measurement of film thickness of oxygen-containing film]
The aluminum resin bonded body and the surface-treated aluminum base material obtained in the manufacturing process of the aluminum resin bonded body are each focused on the sample surface using a type focused ion beam processing apparatus (manufactured by FEI: Quanta 3D type). The observation site was extracted by applying an ion beam to repel atoms on the surface and processed into a thin film having a thickness of about 100 nm to prepare an observation sample. The observation was performed using a transmission electron microscope (TEM) (manufactured by FEI: Tecnai G2 F20 S-TWIN) under an acceleration voltage of 200 kV.

[Example 1]
(1) Production of surface-treated aluminum substrate An aluminum substrate having a size of 50 mm x 25 mm was cut out from a commercially available aluminum plate (A5052; plate thickness 2.0 mm). Next, the surface-treated aluminum base material for the test by which the oxygen-containing film | membrane containing a zinc element was formed in the surface by said processing method A (formation of a zinc containing film | membrane) was produced.
The obtained surface-treated aluminum base material was subjected to oxygen content measurement, oxygen strength measurement, and film thickness measurement in the oxygen-containing film.
The results are shown in Table 1.

(2) Resin composition As the thermoplastic resin composition, a PPS resin composition [PPS (1)] containing additive compound a and additive compound b shown in Table 1 and 50% inorganic filler was used. . This PPS resin composition [PPS (1)] is a resin composition having a melt viscosity of 230 Pa · s (310 ° C., 1000 s ⁻¹ ).

(3) Production of aluminum resin joined body After introducing the resin composition obtained above into an injection molding machine, it was set in a mold of a surface-treated aluminum base material injection molding machine for testing, and the mold temperature was 160 ° C. Resin injection molding was performed under injection molding conditions of a cylinder temperature of 320 ° C., an injection speed of 70 mm / s, a pressure holding pressure of 80 MPa, and a pressure holding time of 5 seconds, to produce the test aluminum resin joined body 1 shown in FIG.
This aluminum resin joined body 1 has a surface-treated aluminum substrate 2 having a thickness of 2 mm, a tip joint portion 4 having a size of 5 mm × 5 mm × 10 mm at the tip, and a thickness other than the tip joint 4 is 4 mm. The aluminum resin joined body 1 is joined at the tip joint 4 and has a joint area of 50 mm ² , and a 1.5 mmφ pin gate 5 is formed in the tip joint 4 portion. Yes.

[Evaluation test of bonding strength of aluminum resin bonded body]
The aluminum resin bonded body 1 was subjected to an evaluation test of the bonding strength between the aluminum and the resin by the following method.
As shown in FIG. 2, the surface-treated aluminum base material 2 of the aluminum resin joined body 1 is fixed to the jig 6, and a load 7 is applied to the upper end of the PPS molded body 3 from above at a speed of 1 mm / min. The test which destroys the junction part between the processed aluminum base material 2 and the resin molding 3 was implemented. Thereafter, the resin cohesive failure rate was determined by visual judgment on the aluminum side of the fracture surface.
The results are shown in Table 1.

[Examples 2 to 47]
The aluminum substrate, the film formation treatment of the oxygen-containing film, the oxygen-containing film, the resin composition, and the resin molding conditions are as shown in Tables 1 to 8, respectively. Went.
In Example 29, a 30 wt% HNO ₃ solution was used, and in Example 30, the electrical conductivity of hot water was adjusted to the values shown in Table 5 using 0.1 M NaOH water.

  In Examples 3, 4, 12-14, 18, 23, 24, 29-34, 42, 43, 45, and 46, the same PPS resin composition [PPS (1)] as in Example 1 was used. Using. In Example 2 using PPS resin [PPS (2)], 40% by mass of a glass-based filler was added to the resin composition, and Examples 5 to 9 using PBT were used. 15 to 17, 19 to 22, 25 to 28, 35, 36, 44, and 47, and Examples 10 and 11 using PP, 30% by mass of a glass-based filler was added to the resin composition. Furthermore, in Examples 37 to 40 using POM, 25% by mass of a glass-based filler is added, and in Example 41 using LCP, 50% by mass of glass is added. System filler material is added.

  Further, in Examples 3 and 27, the following thermal shock test was performed as a durability evaluation test using the same test piece as the aluminum-resin bonded body used in the bonding strength evaluation test. The subsequent bonding strength was evaluated.

(Cool thermal shock test)
Using a thermal shock tester (manufactured by ESPEC Corporation), a thermal shock test is performed under predetermined cycle conditions, taken out after 100 cycles, and a joint strength evaluation test is performed in the same manner as in Example 1 to evaluate durability. did.
In Example 3, the cycle condition is as follows. In Example 3, after heating at 160 ° C. for 1.5 hours, the temperature is lowered to −40 ° C., cooled for 1.5 hours, and then heated to 160 ° C. again. In Example 27, after heating at 140 ° C. for 1.5 hours, the heating-cooling process in which the temperature is lowered to −40 ° C., cooled for 1.5 hours, and then heated again to 140 ° C. is 1 cycle. It was.
The results are shown in Tables 1-8.

[Comparative Examples 1-18]
The aluminum substrate, the film formation treatment of the oxygen-containing film, the oxygen-containing film, the resin composition, and the resin molding conditions are as shown in Table 9 to Table 11, respectively. Went.

  In Comparative Examples 4 and 7 to 10, the same PPS resin composition [PPS (1)] as in Example 1 was used. In Comparative Examples 1, 11, 17, and 18 using PPS resin [PPS (2)], 40% by mass of a glass-based filler was added to the resin composition, and PBT was used. In Comparative Examples 2, 5, 12 and 16, and Comparative Examples 3, 6 and 15 using PP, 30% by mass of a glass filler is added to the resin composition, and POM is used. In Comparative Example 13, 25% by mass of the glass-based filler was added, and in Comparative Example 14 using LCP, 30% by mass of the glass-based filler was added.

Moreover, in Comparative Examples 4-6, the roughening process as a pre-process and the film formation process (surface treatment) which forms an oxygen-containing film are not performed, and an oxygen-containing film is formed in Comparative Examples 9 and 10. An aluminum resin joined body was prepared in the same manner as in the above example except that an aluminum substrate was used without performing the film forming process (surface treatment) to be performed, and the joint strength was evaluated in the same manner as in Example 1. A test was conducted.
In Comparative Examples 7 and 8, the electrical conductivity of hot water was adjusted to the values shown in Table 10 using 0.1 M NaOH water.
The results are shown in Tables 9-11.

[Reference example of film formation treatment of oxygen-containing film]
The same aluminum base material as in Example 1 was subjected to a film formation treatment with hot water at 95 ° C. for 1 minute using tap water having a conductivity of 25 mS / m.
As a result, although the thickness of the oxygen-containing film formed on the surface of the aluminum base material varied, it was only 0.02 to 0.05 μm.

  Since the metal resin bonded body of the present invention has excellent bonding strength before and after the durability test, it is suitably used for manufacturing various parts such as parts for various sensors for automobiles, parts for home appliances and parts for industrial equipment. Is possible.

  DESCRIPTION OF SYMBOLS 1 ... Aluminum resin joined body, 2 ... Surface-treated aluminum base material, 3 ... PPS molded object (resin molded object), 4 ... Tip junction part, 5 ... Pin gate, 6 ... Jig, 7 ... Load.

Claims (16)

A metal base material made of metal, an oxygen-containing film containing oxygen formed by intentionally increasing the oxygen content on the surface of the metal base material, and the oxygen-containing film are joined to each other. A resin molded body formed of a thermoplastic resin composition,
The thermoplastic resin composition contains an additive compound having a functional group that reacts with the oxygen-containing film,
The additive compound is selected from the group consisting of carboxyl groups and salts thereof and esters thereof, epoxy groups, glycidyl groups, isocyanate groups, carbodiimide groups, amino groups and salts thereof, and acid anhydride groups and esters thereof. Having at least one functional group ,
A metal resin joined body, wherein the functional group of the additive compound is contained in the thermoplastic resin composition at a rate of 0.5 to 150 μmol / g . The metal resin joined body according to claim 1 , wherein the additive compound is an olefin copolymer containing a structural unit derived from α-olefin and a structural unit derived from a glycidyl ester of α, β-unsaturated acid. The metal resin joined body according to claim 1 or 2 , wherein the additive compound is an olefin copolymer that is an olefin copolymer further including a structural unit derived from a (meth) acrylic acid ester. In the metal substrate having an oxygen-containing film on the surface before the resin molded body is bonded, the oxygen content measured by EPMA in the surface layer from the outermost surface to a depth of 3 μm is in the range of 0.1 to 50% by weight. The metal-resin joined body according to any one of claims 1 to 3, wherein The metal resin bonded body according to any one of claims 1 to 4, wherein the bonding method for bonding the resin molded body on the oxygen-containing film is a method by injection molding or thermocompression bonding. The metal resin joined body according to any one of claims 1 to 5, wherein the metal base material on which the oxygen-containing film is formed is an aluminum base material made of aluminum or an aluminum alloy. The metal resin joined body according to any one of claims 1 to 6 , wherein the oxide film obtained by the film formation treatment is an oxide film having a thickness of 0.06 µm to 2 µm. A film forming step of forming an oxygen-containing film by intentionally increasing the oxygen content on the surface of a metal base material made of metal, and oxygen of the surface-treated metal substrate obtained in this film forming step A resin molding step of forming a resin molding by injection molding of a thermoplastic resin composition on the containing film;
It is a method for producing a metal resin joined body for producing a metal resin joined body in which a metal substrate and a resin molded body are joined through the oxygen-containing film,
The thermoplastic resin composition contains an additive compound having a functional group that reacts with an oxygen-containing film,
The additive compound is selected from the group consisting of carboxyl groups and salts thereof and esters thereof, epoxy groups, glycidyl groups, isocyanate groups, carbodiimide groups, amino groups and salts thereof, and acid anhydride groups and esters thereof. A method for producing a gold resin joined body, comprising at least one functional group. The method for producing a metal-resin bonded body according to claim 8 , wherein the metal substrate on which the oxygen-containing film is formed is an aluminum substrate made of aluminum or an aluminum alloy. In the film forming step, the aluminum substrate is immersed in a zinc ion-containing alkaline aqueous solution containing alkali hydroxide (MOH) and zinc ions (Zn ²⁺ ) in a weight ratio (MOH / Zn ²⁺ ) of 1 to 100. The method for producing a metal-resin bonded body according to claim 9 , wherein a zinc-containing film containing zinc element is formed on the surface of the aluminum base material by a film forming process. Claims alkali source in the zinc ion-containing aqueous alkali solution, sodium hydroxide, and wherein the potassium hydroxide, and is any one or more alkali hydroxide selected from the group consisting of lithium hydroxide Item 11. A method for producing a metal resin joined body according to Item 9 or 10 . The zinc ion source in the alkaline aqueous solution containing zinc ions is one or more zinc salts selected from the group consisting of zinc oxide, zinc hydroxide, zinc peroxide, zinc chloride, zinc sulfate, and zinc nitrate. The method for producing a metal-resin bonded body according to any one of claims 9 to 11 , wherein In the film forming step, the thickness of the surface of the aluminum base material is set to 0. 1 by a film forming process using hot water having a conductivity of 0.01 mS / m to 20 mS / m and 91 ° C to 100 ° C. The method for producing a metal-resin bonded body according to claim 9 , wherein a hydrated oxide film having a thickness of 1 μm to 1 μm is formed. In the film forming step, the thickness of the surface of the aluminum base material is 0.1 μm by a film forming process using hot water having an electrical conductivity of 0.01 mS / m to 20 mS / m and 60 ° C. to 90 ° C. The method for producing a metal-resin bonded body according to claim 9 , wherein a hydrated oxide film having a thickness of 1 μm or less is formed. The method for producing a metal-resin bonded body according to claim 9 , wherein, in the film forming step, an oxide film is formed by a film forming process for performing a laser process for heating the vicinity of the surface of the aluminum substrate. The thermoplastic resin constituting the thermoplastic resin composition is a polyarylene sulfide resin, a polyester resin, a polycarbonate resin, a polyacetal resin, a polyether resin, a polyphenylene ether resin, a polyimide resin, or a polyetherimide resin. The liquid crystal polymer, the sulfone resin, the polyphenylene oxide resin, the polyamide resin, and the polypropylene resin, any one or two or more resins selected from the group consisting of : The manufacturing method of the metal resin joined body in any one of.

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