Surface treatment aqueous solution, method for producing surface treatment alloy, and composite and method for producing the same

Abstract

An aqueous solution for surface treatment for treating a surface of an alloy, the aqueous solution for surface treatment containing: a copper compound having a copper ion concentration of 20,000 ppm or more and 50,000 ppm or less, a heterocyclic nitrogen compound having a concentration of 200 ppm or more and 3,000 ppm or less, and a halide ion having a concentration of 2,000 ppm or more and 70,000 ppm or less.

Description

TECHNICAL FIELD

[0001] The present application relates to a water solution for surface treatment, a method for manufacturing a surface-treated alloy, and a composite and a method for manufacturing the same. BACKGROUND

[0002] In the past, various techniques have been known to join metal alloys and resins. As one of them, a method to join them with an adhesive can be cited, and many adhesives for the same have been developed. As such adhesives, for example, adhesives that can join them at normal temperature or by heating are known.

[0003] On the other hand, techniques to join metal alloys and resins without using an adhesive have also been studied. For example, a method to integrate a high-strength thermoplastic engineering resin to a light metal alloy of magnesium, aluminum, and a ferrous alloy such as stainless steel without intervention of an adhesive by injection or the like is known.

[0004] As a technique to join metal alloys and resins with these adhesives or without using an adhesive, a technique to make the surface of a metal alloy porous in order to improve the joinability thereof has also been proposed. For example, in Patent Literature 1, in order to provide a joined body in which a metal alloy and an adherend are firmly joined with an unsaturated polyester-based adhesive and the like, a joined body of a metal alloy and an adherend is disclosed, which is characterized in that it is a joined body in which a metal alloy and an adherend are joined with an adhesive, and to the surface of the aforementioned metal alloy, a micron-order roughness having a peak-valley average interval (RSm) of 0.8 to 10 μm and a maximum height roughness (Rz) of 0.2 to 5 μm is imparted by performing etching, and a super-fine concavo-convex having a period of 5 to 500 nm is formed in the plane having the roughness, and a surface layer is a thin layer of a metal oxide or a metal phosphide, the aforementioned adhesive is a main component of an unsaturated polyester resin or a vinyl ester resin, the adhesive is impregnated into the super-fine concavo-convex, and thereby the aforementioned metal alloy and the aforementioned adherend are firmly joined.

[0005] PRIOR ART DOCUMENTS

[0006] PATENT LITERATURE

[0007] Patent Literature 1: International Publication No. 2009 / 093668 SUMMARY

[0008] Problems to be solved by the invention

[0009] However, in the case where a resin composition is used as an adherend and a metal alloy is joined to the resin composition as an adherend without using an adhesive, the joining strength of the metal alloy to the resin composition in the prior art cannot be said to be sufficient, and further improvement is possible. As a method for such improvement, a method is considered in which a treatment liquid is brought into contact with the surface of a metal alloy to thereby roughen the surface of the metal alloy to the extent of further improving the joining strength of the metal alloy to the resin composition. Although a technique for roughening (porous) the surface of a metal alloy is also described in Patent Literature 1, further improvement is possible for direct joining of a metal alloy to a resin composition.

[0010] The present application was made in view of the above-described actual circumstances, and has an object to provide an aqueous solution for surface treatment of an alloy capable of improving the joining strength of the alloy to a resin composition, a method for producing a surface-treated alloy using the aqueous solution for surface treatment, and a composite having the surface-treated alloy and a method for producing the same.

[0011] Solution to the problem

[0012] The present inventors etc. have made intensive studies in order to achieve the above object, and as a result, have found that by setting an aqueous solution for surface treatment of an alloy to a specific composition, the joining strength between the alloy and a resin composition can be improved, thereby completing the present application.

[0013] That is, the present application is as follows.

[0014] [1] An aqueous solution for surface treatment for treating the surface of an alloy, the aqueous solution for surface treatment containing: a copper compound having a copper ion concentration of 20,000 ppm or more and 50,000 ppm or less, a heterocyclic nitrogen compound having a concentration of 200 ppm or more and 3,000 ppm or less, and a halide ion having a concentration of 2,000 ppm or more and 70,000 ppm or less.

[0015] [2] The aqueous solution for surface treatment described above, wherein the heterocyclic nitrogen compound is an azole compound.

[0016] [3] The aqueous solution for surface treatment described above, wherein the azole compound is one or more selected from the group consisting of pyrazole, 5-amino tetrazole, and imidazole.

[0017] [4] The aqueous solution for surface treatment described above, wherein the copper compound is one or more selected from the group consisting of copper sulfate and copper bromide.

[0018] [5] The aqueous solution for surface treatment described above, wherein the halide ion is one or more selected from the group consisting of bromide ion and chloride ion.

[0019] [6] The aqueous solution for surface treatment according to the above, wherein the alloy is an aluminum alloy.

[0020] [7] A method for producing a surface-treated alloy, comprising: a step of bringing an aqueous solution for surface treatment according to the above into contact with a surface of an alloy; and a step of removing copper, which is deposited on the surface of the alloy in the step of contact, by dissolving or dispersing the copper in an aqueous solution containing an oxidizing agent and an acid, thereby obtaining a surface-treated alloy.

[0021] [8] The method for producing according to the above, wherein the oxidizing agent is a peroxide.

[0022] [9] The method for producing according to the above, wherein the acid is an inorganic acid.

[0023]

[10] A composite body comprising: a surface-treated alloy obtained by the method for producing according to the above, and a resin composition containing a thermoplastic resin, the resin composition being joined to the surface-treated alloy.

[0024]

[11] A method for producing a composite body, comprising: a step of joining a surface-treated alloy obtained by the method for producing according to the above to a resin composition containing a thermoplastic resin, thereby obtaining a composite body.

[0025]

[12] The method for producing a composite body according to the above, further comprising a step of inserting the surface-treated alloy into a mold before the step of obtaining the composite body, and in the step of obtaining the composite body, a resin composition containing a thermoplastic resin is injected into the mold to be molded, thereby joining the surface-treated alloy to the resin composition.

[0026] Effects of the invention

[0027] According to the present application, it is possible to provide an aqueous solution for surface treatment of an alloy capable of improving the joining strength of the alloy to a resin composition, a method for producing a surface-treated alloy using the aqueous solution for surface treatment, and a composite body comprising the surface-treated alloy and a method for producing the same. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 A laser microscope image of the surface of the composite body of Example 1.

[0029] Figure 2 A laser microscope image of the surface of the composite body of Example 2.

[0030] Figure 3 A laser microscope image of the surface of the composite body of Example 3.

[0031] Figure 4 A laser microscope image of the surface of the composite body of Example 4.

[0032] Figure 5 A laser microscope image of the surface of the composite of Example 5.

[0033] Figure 6 A laser microscope image of the surface of the composite of Example 6.

[0034] Figure 7 A laser microscope image of the surface of the composite of Example 7.

[0035] Figure 8 A laser microscope image of the surface of the composite of Example 8.

[0036] Figure 9 A laser microscope image of the surface of the composite of Example 9.

[0037] Figure 10 A laser microscope image of the surface of the composite of Example 10.

[0038] Figure 11 A laser microscope image of the surface of the composite of Comparative Example 1.

[0039] Figure 12 A laser microscope image of the surface of the composite of Comparative Example 2.

[0040] Figure 13 A laser microscope image of the surface of the composite of Comparative Example 3.

[0041] Figure 14 A laser microscope image of the surface of the composite of Comparative Example 4.

[0042] Figure 15 A laser microscope image of the surface of the composite of Comparative Example 5.

[0043] Figure 16 A laser microscope image of the surface of the composite of Comparative Example 6.

[0044] Figure 17 A laser microscope image of the surface of the composite of Comparative Example 7. DETAILED DESCRIPTION

[0045] Hereinafter, modes for carrying out the present application (hereinafter, simply referred to as "the present embodiment") will be explained in detail as needed with reference to the accompanying drawings, but the present application is not limited to the following present embodiment. The present application can be variously modified within the scope of the gist thereof.

[0046] The surface treatment aqueous solution of the present embodiment is a surface treatment aqueous solution for treating the surface of an alloy, and contains a copper compound having a copper ion concentration of 20,000 ppm or more and 50,000 ppm or less, a heterocyclic nitrogen compound having a concentration of 200 ppm or more and 3,000 ppm or less, and a halide ion having a concentration of 2,000 ppm or more and 50,000 ppm or less. The alloy treated using such a surface treatment aqueous solution (hereinafter, referred to as "surface treatment alloy") is roughened so that the surface thereof has a roughness of the order of micrometers. Therefore, when the surface treatment alloy is joined with a resin composition, the resin composition is immersed into recesses on the surface of the surface treatment alloy. As a result, the resin composition is joined with the surface treatment alloy by an anchoring effect, and thus the joining strength between the surface treatment alloy and the resin composition can be improved. The main factor of the surface of the alloy being roughened so as to have a roughness of the order of micrometers when using the above-described surface treatment aqueous solution (hereinafter, also simply referred to as "aqueous solution") is not determined, but the present inventors and others consider that the main factor is as follows. However, the main factor is not limited to the following. That is, the surface of the alloy is brought into contact with the aqueous solution, and thus the surface of the alloy is oxidized to form a local cell. As a result, by the cell reaction, among the metals contained in the alloy, the metal having a lower potential existing in the vicinity of the surface of the alloy is dissolved in the aqueous solution, and the copper ion in the aqueous solution having a higher potential is precipitated as metallic copper on the surface of the alloy in an appropriate amount. At this time, the aqueous solution of the present embodiment controls the shape of the precipitated copper by containing the heterocyclic nitrogen compound at a prescribed concentration, and thus the heterocyclic nitrogen compound interacts with the copper ion, and controls the shape of the precipitated copper, thereby having a function of also controlling the roughened shape of the alloy dissolved in the aqueous solution. Furthermore, the copper precipitated on the surface of the alloy is dissolved or dispersed and removed. At this time, the aqueous solution of the present embodiment has a function of promoting the dissolution of the oxide of the alloy in the aqueous solution by containing the halide ion at a prescribed concentration, and thus reacting with the oxide formed on the surface of the alloy. In this way, the surface of the alloy (surface treatment alloy) is made to have a concave-convex having a depth of the order of μm.

[0047] As the copper compound that is the source of the copper ion contained in the aqueous solution of the present embodiment, for example, copper sulfate which can be anhydride or pentahydrate, copper tetrafluoroborate, copper bromide, copper oxide, copper phosphate, copper acetate, copper formate, and copper nitrate can be cited. Among these, from the viewpoint of more effectively and reliably exerting the effect based on the present application, copper sulfate and copper bromide are preferred, and copper sulfate is more preferred. They can be used alone or in combination with two or more.

[0048] The concentration of the above-described copper compound in the aqueous solution is not particularly limited as long as it is 20,000 ppm or more and 50,000 ppm or less, preferably 20,000 ppm or more and 45,000 ppm or less, and particularly preferably 25,000 ppm or more and 45,000 ppm or less in terms of the concentration of copper ions. By setting the concentration of copper ions within the above-described range, the main metal ions in the alloy can be dissolved more effectively and reliably, and the effect of precipitating the copper compound on the alloy can be exerted more effectively and reliably. In addition, by setting the concentration of copper ions to 50,000 ppm or less, the precipitation of copper ions can be suppressed more effectively and reliably.

[0049] From the viewpoint of more effectively and reliably roughening the surface of the alloy, the aqueous solution of the present embodiment contains a heterocyclic nitrogen compound. It is considered that the heterocyclic nitrogen compound interacts with copper ions, controls the shape of precipitated copper, and thus has a function of also controlling the roughening shape of the alloy dissolved in the aqueous solution. The heterocyclic nitrogen compound is not particularly limited as long as it is a compound having a heterocycle containing a nitrogen atom in the ring, and from the viewpoint of more effectively and reliably exerting the effect based on the present application, an azole-based compound is preferred. Here, the azole-based compound refers to a 5-membered heterocyclic compound having one or more nitrogen atoms in the ring. As the azole-based compound, for example, pyrazole, imidazole, triazole, 5-amino tetrazole, and tetrazole, each optionally having a substituent, can be exemplified. Among these, from the viewpoint of more effectively and reliably exerting the effect based on the present application, pyrazole, 5-amino tetrazole, and imidazole are more preferred, and pyrazole is further preferred. They can be used alone or in combination with two or more.

[0050] The concentration of the heterocyclic nitrogen compound in the aqueous solution is 200 ppm or more and 3,000 ppm or less, more preferably 200 ppm or more and 2,000 ppm or less, and further preferably 300 ppm or more and 1,000 ppm or less. When the concentration is 200 ppm or more, the surface of the alloy can be roughened more effectively and reliably, and a concave-convex shape suitable for bonding with a resin can be imparted to the surface of the alloy. In addition, when the concentration is 3,000 ppm or less, the surface of the alloy can be roughened more effectively and reliably.

[0051] From the viewpoint of more effectively and reliably roughening the surface of the alloy, the aqueous solution of the present embodiment contains a halide ion. It is considered that the halide ion reacts with the oxide formed on the surface of the alloy, and thus has a function of promoting the dissolution of the oxide of the alloy in the aqueous solution. As the halide ion, for example, chloride ions and bromide ions can be exemplified. Among these, from the viewpoint of more effectively and reliably exerting the effect based on the present application, chloride ions are preferred.

[0052] The concentration of the halide ion in the aqueous solution is 2000 ppm or more and 70000 ppm or less, more preferably 2000 ppm or more and 50000 ppm or less, further preferably 2000 ppm or more and 40000 ppm or less. When the concentration of the halide ion is 2000 ppm or more and 70000 ppm or less, the oxide film present on the alloy is further dissolved, and the effect of further activating the reaction of copper with the alloy is exerted. When the concentration is 2000 ppm or more and 40000 ppm or less, the surface of the alloy can be more effectively and reliably roughened.

[0053] As the halide that provides the halide ion, for example, halides of alkali metals such as sodium halide and potassium halide, halides of alkaline earth metals such as calcium halide, and ammonium halide, and halides of copper can be exemplified. Among these, from the viewpoint of more effectively and reliably exerting the effect based on the present application, halides of alkali metals, more preferably chlorides of alkali metals, further preferably sodium chloride are preferred. They can be used alone as one kind or in combination as two or more kinds. Note that the halide can be repeated with the above-described copper compound. For example, in the case where a halide of copper is used as the halide, this halide of copper also belongs to the above-described copper compound.

[0054] The aqueous solution of the present embodiment can contain various additives that are generally used in the surface treatment of alloys, within a range that does not impair the effects based on the present application. The additives can be used alone as one kind or in combination as two or more kinds.

[0055] The aqueous solution of the present embodiment, by being brought into contact with the surface of an alloy, can produce a surface-treated alloy in which the surface of the alloy is roughened to have a roughness of the order of micrometers. Therefore, when this surface-treated alloy is joined with a resin composition, the resin composition is immersed into the recesses on the surface of the surface-treated alloy. As a result, the resin composition is joined with the surface-treated alloy by an anchoring effect, and thus the joining strength between the surface-treated alloy and the resin composition can be improved. In addition, the aqueous solution of the present embodiment can roughen a wide range of alloys having different compositions to have a desired roughness on the surface. Therefore, in the case where a plurality of alloys having different compositions are treated, it is not necessary to change the kind or composition of the solution for each alloy, and the trouble and time for producing the surface-treated alloy can be reduced.

[0056] The production method of the surface-treated alloy of the present embodiment has the following steps: a step of bringing the above-described aqueous solution into contact with the surface of an alloy (contacting step); and a step of removing copper that is precipitated on the surface of the alloy in the contacting step by dissolving or dispersing the copper in an aqueous solution containing an oxidizing agent and an acid (hereinafter also referred to as "oxidizing agent-acid aqueous solution") (copper removal step), thereby obtaining a surface-treated alloy.

[0057] In the contacting step, the above aqueous solution is brought into contact with the surface of the alloy. The alloy, i.e., the alloy before being treated with the aqueous solution for surface treatment of the present embodiment, is not particularly limited, and, for example, aluminum alloys, magnesium alloys, molten zinc alloys, and steels can be given.

[0058] Among these, from the viewpoint of more effectively and reliably exerting the effect based on the present application, an aluminum alloy is preferred. The aluminum alloy is not particularly limited, and, for example, aluminum alloys of a pure aluminum system having an aluminum content of 99 mass% or more, aluminum-copper systems mainly containing copper other than aluminum, aluminum-manganese systems mainly containing manganese other than aluminum, and aluminum-magnesium alloys mainly containing magnesium other than aluminum can be given. More specifically, all alloys of the A1000 series to the 7000 series (corrosion-resistant aluminum alloys, high-strength aluminum alloys, heat-resistant aluminum alloys, etc.) prescribed in Japanese Industrial Standards (JIS) as wrought aluminum alloys, such as the A1100 alloy, the A1085 alloy, the A1050 alloy, the A2024 alloy of the aluminum-copper system, the A3003 alloy of the aluminum-manganese system, the A5052 alloy of the aluminum-magnesium system, etc., and cast aluminum alloys such as ADC1 to 12 (aluminum alloys for die casting) can be given.

[0059] As the composition of the aluminum alloy, for example, the content of each element is 1.5 mass% or less for silicon (Si), 1.0 mass% or less for iron (Fe), 8.0 mass% or less for copper (Cu), 2.0 mass% or less for manganese (Mn), 6.0 mass% or less for magnesium (Mg), 0.50 mass% or less for chromium (Cr), 8.0 mass% or less for zinc (Zn), 0.30 mass% or less for titanium (Ti), 0.25 mass% or less for vanadium (V), 1.0 mass% or less for bismuth (Bi), 1.0 mass% or less for lead (Pb), and the balance being aluminum (Al) and unavoidable impurities. The composition of the aluminum alloy is exemplified in Table 1, but the composition is not limited to these.

[0060] [Table 1]

[0061]

[0062] In addition, the alloy as a raw material can be a cast alloy, or a member shaped into a prescribed shape by a die casting method, or a member shaped into a prescribed shape by mechanical processing. Further, it can be a sheet or the like as an intermediate material in a wrought alloy, or a member shaped into a prescribed shape by mechanical processing such as hot press working. In addition, the shape of the surface-treated alloy is not particularly limited, and, for example, it can be a plate shape and a columnar shape, and an arbitrary shape suitable for its use.

[0063] The magnesium alloy is not particularly limited, and for example, a pure magnesium-based magnesium alloy having a magnesium content of 99 mass% or more, a magnesium-manganese-based magnesium alloy mainly containing aluminum and manganese in addition to magnesium, and a magnesium-zinc alloy mainly containing aluminum and zinc in addition to magnesium can be exemplified. More specifically, all of the magnesium alloys prescribed in Japanese Industrial Standards (JIS), such as an AZ31B alloy of a magnesium-aluminum-zinc system, an AZ91D alloy, an AM60B alloy of a magnesium-aluminum-manganese system, and an AS41A alloy of a magnesium-aluminum-silicon system can be exemplified.

[0064] As the composition of the magnesium alloy, for example, with respect to the content of each element, 12.0 mass% or less of aluminum (Al), 8.0 mass% or less of zinc (Zn), 2.0 mass% or less of manganese (Mn), 3.0 mass% or less of silicon (Si), 0.50 mass% or less of copper (Cu), 0.05 mass% or less of nickel (Ni), 0.01 mass% or less of iron (Fe), and the balance of magnesium (Mg) and inevitable impurities are exemplified. The composition of the magnesium alloy is exemplified in Table 2, but the composition is not limited to these.

[0065] [Table 2]

[0066]

[0067] The temperature (liquid temperature) and the time when the alloy is brought into contact with the above-described aqueous solution in the contact step are not particularly limited as long as they are a temperature and a time capable of achieving the object of the present application, and are preferably 20°C or higher and 70°C or lower, and preferably 30 seconds or more and 10 minutes or less. When the temperature and the time are the above lower limit value or more and the upper limit value or less, the surface of the alloy can be more effectively and reliably roughened as desired.

[0068] The method of bringing the alloy into contact with the above-described aqueous solution in the contact step is not particularly limited, and for example, a method of spraying (spray coating) or misting (mist coating) the aqueous solution to the surface of the alloy, a method of applying the aqueous solution to the surface of the alloy with a brush or a doctor blade, a method of dropping the aqueous solution to the surface of the alloy while rotating the alloy, thereby spreading the aqueous solution over the entire surface of the alloy by the centrifugal force thereof (spin coating), and a method of immersing the alloy in a bath of the aqueous solution (dip coating) can be exemplified. Among these, dip coating is preferred from the viewpoint of more effectively and reliably exerting the effect based on the present application.

[0069] The aqueous solution of the present embodiment can contain various additives generally used in the surface treatment of aluminum alloys within a range not impairing the effects based on the present application. As such additives, for example, an interfacial additive and a pH adjuster can be exemplified. They can be used alone or in combination with two or more.

[0070] In the copper removal step, copper deposited on the surface of the alloy in the contact step is dissolved or dispersed in the oxidizing agent-acid aqueous solution to be removed, whereby the surface-treated alloy is obtained. The oxidizing agent has a function of oxidizing copper deposited on the surface of the alloy to be easily dissolved or dispersed from the surface of the alloy. As the oxidizing agent, for example, hydrogen peroxide, peracetic acid, and peroxides such as persulfate salts can be exemplified. Among these, from the viewpoint of more effectively and reliably exerting the effect of the present application, hydrogen peroxide is preferred. The oxidizing agent can be used alone or in combination with two or more kinds.

[0071] As for the concentration of the oxidizing agent in the oxidizing agent-acid aqueous solution, when the oxidizing agent-acid aqueous solution is taken as 100% by mass, it is preferably 0.5% by mass or more and 20% by mass or less, more preferably 1.0% by mass or more and 10% by mass or less. When the concentration is 0.5% by mass or more, the treatment of the copper removal using the oxidizing agent-acid aqueous solution can be performed more quickly, and when it is 20% by mass or less, it is preferred from the viewpoint of more effectively and reliably exerting the effect of the present application.

[0072] The acid in the oxidizing agent-acid aqueous solution has a function of dissolving or dispersing copper deposited on the surface of the alloy. As the acid, it can be inorganic acid or organic acid. Among these, from the viewpoint of more effectively and reliably exerting the effect of the present application, inorganic acid is preferred. As the inorganic acid, for example, sulfuric acid, nitric acid, hydrochloric acid, and phosphoric acid can be exemplified. As the organic acid, for example, acetic acid, citric acid, lactic acid, and malic acid can be exemplified. However, the inorganic acid and the organic acid are not limited to the above. Among these, from the viewpoint of more effectively and reliably exerting the effect of the present application, sulfuric acid is preferred. The acid can be used alone or in combination with two or more kinds.

[0073] As for the concentration of the acid in the oxidizing agent-acid aqueous solution, when the aqueous solution is taken as 100% by mass, it is preferably 0.5% by mass or more and 20% by mass or less, more preferably 1.0% by mass or more and 10% by mass or less. When the concentration is 0.5% by mass or more, the treatment of the copper removal using the oxidizing agent-acid aqueous solution can be performed more quickly, and when it is 20% by mass or less, it is preferred from the viewpoint of more effectively and reliably exerting the effect of the present application.

[0074] The temperature (liquid temperature) and the time when the surface-treated alloy is contacted with the oxidizing agent-acid aqueous solution in the copper removal step are not particularly limited as long as they are a temperature and a time at which the object of the present application can be achieved, and are preferably 20°C or higher and 70°C or lower, and preferably 30 seconds or more and 10 minutes or less. When the temperature and the time are the above lower limit value or more and the upper limit value or less, copper deposited on the surface of the alloy can be selectively removed more effectively and reliably.

[0075] The method of contacting the surface-treated alloy with the oxidizing agent-acid aqueous solution in the copper removal step is not particularly limited, and for example, the following methods can be listed: a method of spraying (spray coating) or spraying (spray coating) the oxidizing agent-acid aqueous solution onto the surface of the alloy; a method of applying the oxidizing agent-acid aqueous solution to the surface of the alloy with a brush or a doctor blade; a method of dropping the oxidizing agent-acid aqueous solution onto the surface of the alloy while rotating the alloy, thereby spreading the oxidizing agent-acid aqueous solution over the entire surface of the alloy by the centrifugal force thereof (spin coating); and a method of immersing the alloy in a bath of the oxidizing agent-acid aqueous solution (dip coating). Among these, from the viewpoint of more effectively and reliably exerting the effects based on the present application, dip coating is preferred.

[0076] The composite of the present embodiment has the above-described surface-treated alloy and a resin composition containing a thermoplastic resin, and is a composite in which the resin composition is joined to the surface-treated alloy. The resin composition in the composite is a solid, and as the thermoplastic resin contained in the resin composition, for example, polycarbonate (PC), polybutylene terephthalate (PBT), polyethylene terephthalate (PET), polypropylene (PP), polyamide (PA), and polyphenylene sulfide (PPS) can be listed. Among these, from the viewpoint of more effectively and reliably exerting the effects based on the present application, PPS or PA is preferred. The thermoplastic resin can be used alone or in combination with two or more kinds.

[0077] The resin composition of the present embodiment is used as a material for a molded body that is molded by injection molding or the like, and is different from a resin composition used as an adhesive in this respect.

[0078] For the resin composition of the present embodiment, from the viewpoint of bringing the linear expansion coefficients of different kinds of materials close to each other and increasing the tensile strength, for example, it is preferred to contain a fibrous or particulate filler, the filler is more preferably fibrous, and further preferably glass fibers. As the glass fibers, for example, long fibers, short fibers, and cloth products can be listed. The filler can be used alone or in combination with two or more kinds.

[0079] In the case where the resin composition contains a thermoplastic resin and a filler, the content of the thermoplastic resin is preferably 10% by mass or more and 70% by mass or less, and more preferably 15% by mass or more and 70% by mass or less, relative to 100% by mass of the resin composition. In addition, the content of the filler is preferably 10% by mass or more and 70% by mass or less, and more preferably 15% by mass or more and 70% by mass or less, relative to 100% by mass of the resin composition. By bringing the contents of the thermoplastic resin and the filler within the above numerical ranges, the linear expansion coefficients of the surface-treated alloy, in which the surface is roughened with the surface treatment aqueous solution of the present embodiment, and the resin composition become close to each other. As a result, the effect of increasing the joining strength when directly joining different kinds of materials can be made more remarkable.

[0080] The shape of the composite is only required to be a shape suitable for its use. As the use of the composite, for example, automobile parts and aircraft parts can be listed.

[0081] The manufacturing method of the composite of the present embodiment has a step of joining the above surface-treated alloy and the above resin composition to obtain the composite. The joining method is not particularly limited and can be a method known in the past as a method of joining an alloy and a resin composition. The composite of the present embodiment and the manufacturing method thereof are particularly advantageous in that they have excellent joining strength even when the surface-treated alloy and the resin composition are directly joined without the aid of an adhesive by using the above surface-treated alloy.

[0082] In the manufacturing method of the composite of the present embodiment, it is preferable that: before the step of obtaining the above composite, there is a step of inserting (embedding) the surface-treated alloy into a mold, and in the step of obtaining the above composite, the surface-treated alloy and the resin composition are joined by injection molding in which a resin composition containing a thermoplastic resin is injected into the mold to perform molding. According to this manufacturing method, the surface-treated alloy and the resin composition are joined without the aid of an adhesive. However, by using the surface-treated alloy of the present embodiment, the surface-treated alloy and the resin composition can be joined with high joining strength even without using an adhesive. The shape of the mold is only required to be a desired shape, and in addition, the conditions of the injection molding can be appropriately set according to the kind of each material used in the surface-treated alloy and the resin composition.

[0083] Example

[0084] Hereinafter, the present application will be described in more detail by examples, but the present application is not limited to these examples.

[0085] (Aqueous solution for surface treatment)

[0086] The copper compound (all manufactured by Wako Pure Chemical Industries, Ltd.), the heterocyclic nitrogen compound (all manufactured by Wako Pure Chemical Industries, Ltd.), and the halide (all manufactured by Wako Pure Chemical Industries, Ltd.) shown in Table 3 were added to ion exchange water in the proportions shown in Table 3 and mixed to prepare an aqueous solution for surface treatment.

[0087] (Oxidizing agent · aqueous acid solution)

[0088] An oxidizing agent · acid aqueous solution was prepared by adding 0.2 mass% of hydrogen peroxide (manufactured by Takasago Chemical Corporation, 31% aqueous solution) and 0.6 mass% of sulfuric acid (manufactured by Wako Pure Chemical Industries, Ltd.) to ion exchange water and mixing. Or an oxidizing agent · acid aqueous solution was prepared by adding 20 mass% of ammonium persulfate (manufactured by Mitsubishi Gas Chemical Company, Inc.) and 0.5 mass% of nitric acid (manufactured by Wako Pure Chemical Industries, Ltd.) to ion exchange water and mixing.

[0089] (Surface roughness measurement of alloy)

[0090] The arithmetic average curvature (Spc) of the peak vertex in a range of 70 μm x 70 μm was measured for a plate-shaped surface-treated alloy (size: 50 mm x 20 mm x 1.5 mm) using a laser microscope (manufactured by KEYENCE CORPORATION, product name "VK-X250").

[0091] (Surface observation of alloy)

[0092] The surface shape of the sample of the surface-treated alloy was observed using a laser microscope (manufactured by KEYENCE CORPORATION, product name "VK-X250").

[0093] (Composite molding based on injection molding)

[0094] An insert mold was installed in an injection molding machine (manufactured by Nippon Steel, product name "J110AD"), and a surface-treated alloy having a prescribed shape was set in the mold. The mold was previously heated to 120°C. Next, a PPS resin composition (manufactured by Toho Rayon Co., product name "SUSTEEL GS-40") in which 40 mass% of glass fiber was compounded as a filler was injection-molded at a nozzle temperature of 310°C, an injection speed of 15 mm / sec, an injection pressure of 250 MPa, a holding pressure of 130 MPa, a holding time of 4 seconds, and then cooled in the mold, whereby a composite in which the surface-treated alloy and the PPS resin composition were joined and integrated was obtained. Alternatively, a PA resin composition (manufactured by Mitsubishi Engineering-Plastics Corporation, product name "RENY 1002H") in which 30 mass% of glass fiber was compounded as a filler was injection-molded at a nozzle temperature of 280°C, an injection speed of 15 mm / sec, an injection pressure of 250 MPa, a holding pressure of 130 MPa, a holding time of 4 seconds, and then cooled, whereby a composite in which the surface-treated alloy and the PA resin composition were joined and integrated was obtained. Alternatively, a PBT resin composition (manufactured by Mitsubishi Engineering-Plastics Corporation, product name "NOVADURAN 5010G30") in which 30 mass% of glass fiber was compounded as a filler was injection-molded at a nozzle temperature of 250°C, an injection speed of 15 mm / sec, an injection pressure of 250 MPa, a holding pressure of 130 MPa, a holding time of 4 seconds, and then cooled, whereby a composite in which the surface-treated alloy and the PBT resin composition were joined and integrated was obtained.

[0095] (Tensile test)

[0096] The composite obtained by the above operation was subjected to a tensile test to measure the tensile strength (joining strength) between the surface-treated alloy and the resin composition, using a tensile tester (manufactured by Shimadzu Corporation, product name "AGS-X") in accordance with JIS K6850.

[0097] (Example 1)

[0098] An aluminum alloy sheet (JIS A5052-H34) having a thickness of 1.5 mm and a size of 50 mm x 20 mm was prepared. First, the above aluminum alloy sheet was immersed in the surface treatment aqueous solution at a liquid temperature of 40°C for 1 minute, whereby an alloy sheet from which copper was deposited on the surface was obtained. Next, the alloy sheet was sufficiently washed with ion exchange water, and then immersed in an oxidizing agent / acid aqueous solution at a liquid temperature of 40°C until the deposited copper was removed, and then sufficiently washed with ion exchange water. Thereafter, the alloy sheet from which the copper was removed was dried in a warm air drier set to 50°C for 1 hour, whereby a surface-treated alloy was obtained. The obtained surface-treated alloy was observed in accordance with the above "Observation of the surface of the alloy". The laser microscope image thereof is shown in Fig. 1. Figure 1Further, the Spc of the surface of the surface-treated alloy was measured according to the above-described "Surface roughness measurement of alloy", and the result was 82418 / mm. Furthermore, the tensile strength (bonding strength) between the surface-treated alloy and the PPS resin composition was measured according to the above-described "Tensile test", and the result was 31 MPa. Note that the laser microscope images of each of the examples shown are images at the same magnification.

[0099] (Example 2)

[0100] An aluminum alloy sheet (JIS A5052-H34) having a thickness of 1.5 mm and a size of 50 mm x 20 mm was prepared. First, the above-described aluminum alloy sheet was immersed in the surface treatment aqueous solution at a liquid temperature of 40°C for 1 minute to obtain an alloy sheet from which copper was precipitated on the surface thereof. Next, the alloy sheet was sufficiently washed with ion exchange water, and then immersed in the oxidizing agent-acid aqueous solution at a liquid temperature of 40°C until the precipitated copper could be removed, and then sufficiently washed with ion exchange water. Thereafter, the alloy sheet from which the copper was removed was dried in a warm air dryer set to 50°C for 1 hour to obtain a surface-treated alloy. The obtained surface-treated alloy was observed according to the above-described "Surface observation of alloy". The laser microscope image thereof is shown in Figure 2 Further, the Spc of the surface of the surface-treated alloy was measured according to the above-described "Surface roughness measurement of alloy", and the result was 51620 / mm. Furthermore, the tensile strength (bonding strength) between the surface-treated alloy and the PPS resin composition was measured according to the above-described "Tensile test", and the result was 20 MPa.

[0101] (Example 3)

[0102] An aluminum alloy sheet (JIS A5052-H34) having a thickness of 1.5 mm and a size of 50 mm x 20 mm was prepared. First, the above-described aluminum alloy sheet was immersed in the surface treatment aqueous solution at a liquid temperature of 40°C for 1 minute to obtain an alloy sheet from which copper was precipitated on the surface thereof. Next, the alloy sheet was sufficiently washed with ion exchange water, and then immersed in the oxidizing agent-acid aqueous solution at a liquid temperature of 40°C until the precipitated copper could be removed, and then sufficiently washed with ion exchange water. Thereafter, the alloy sheet from which the copper was removed was dried in a warm air dryer set to 50°C for 1 hour to obtain a surface-treated alloy. The obtained surface-treated alloy was observed according to the above-described "Surface observation of alloy". The laser microscope image thereof is shown in Figure 3 Further, the Spc of the surface of the surface-treated alloy was measured according to the above-described "Surface roughness measurement of alloy", and the result was 101311 / mm. Furthermore, the tensile strength (bonding strength) between the surface-treated alloy and the PPS resin composition was measured according to the above-described "Tensile test", and the result was 22 MPa.

[0103] (Example 4)

[0104] An aluminum alloy sheet (JIS A5052-H34) having a thickness of 1.5 mm and a size of 50 mm x 20 mm was prepared. First, the above aluminum alloy sheet was immersed in the aqueous solution for surface treatment at a liquid temperature of 40°C for 1 minute to obtain an alloy sheet from which copper was precipitated on the surface thereof. Next, the alloy sheet was sufficiently washed with ion exchange water, and then immersed in the oxidizing agent-acid aqueous solution at a liquid temperature of 40°C until the precipitated copper could be removed, and further sufficiently washed with ion exchange water. Thereafter, the alloy sheet from which copper was removed was dried in a warm air drier set at 50°C for 1 hour to obtain a surface-treated alloy. The obtained surface-treated alloy was observed in accordance with the above "Surface observation of alloy". The laser microscope image thereof is shown in Figure 4 . In addition, the Spc of the surface of the surface-treated alloy was measured in accordance with the above "Surface roughness measurement of alloy", and the result was 52301 / mm. Further, the tensile strength (joint strength) between the surface-treated alloy and the PPS resin composition was measured in accordance with the above "Tensile test", and the result was 25 MPa.

[0105] (Example 5)

[0106] An aluminum alloy sheet (JIS A5052-H34) having a thickness of 1.5 mm and a size of 50 mm x 20 mm was prepared. First, the above aluminum alloy sheet was immersed in the aqueous solution for surface treatment at a liquid temperature of 40°C for 1 minute to obtain an alloy sheet from which copper was precipitated on the surface thereof. Next, the alloy sheet was sufficiently washed with ion exchange water, and then immersed in the oxidizing agent-acid aqueous solution at a liquid temperature of 40°C until the precipitated copper could be removed, and further sufficiently washed with ion exchange water. Thereafter, the alloy sheet from which copper was removed was dried in a warm air drier set at 50°C for 1 hour to obtain a surface-treated alloy. The obtained surface-treated alloy was observed in accordance with the above "Surface observation of alloy". The laser microscope image thereof is shown in Figure 5 . In addition, the Spc of the surface of the surface-treated alloy was measured in accordance with the above "Surface roughness measurement of alloy", and the result was 52301 / mm. Further, the tensile strength (joint strength) between the surface-treated alloy and the PPS resin composition was measured in accordance with the above "Tensile test", and the result was 25 MPa.

[0107] (Example 6)

[0108] An aluminum alloy sheet (JIS A5052-H34) having a thickness of 1.5 mm and a size of 50 mm x 20 mm was prepared. First, the above aluminum alloy sheet was immersed in the aqueous solution for surface treatment at a liquid temperature of 40°C for 1 minute to obtain an alloy sheet from which copper was deposited on the surface. Next, the alloy sheet was sufficiently washed with ion exchange water, and then immersed in the oxidizing agent-acid aqueous solution at a liquid temperature of 40°C until the deposited copper could be removed, and further sufficiently washed with ion exchange water. Thereafter, the alloy sheet from which copper was removed was dried in a warm air drier set at 50°C for 1 hour to obtain a surface-treated alloy. The obtained surface-treated alloy was observed in accordance with the above "Surface observation of alloy". The laser microscope image thereof is shown in Figure 6 In addition, the Spc of the surface of the surface-treated alloy was measured in accordance with the above "Surface roughness measurement of alloy", and the result was 44500 / mm. Further, the tensile strength (bonding strength) between the surface-treated alloy and the PPS resin composition was measured in accordance with the above "Tensile test", and the result was 18 MPa.

[0109] (Example 7)

[0110] An aluminum alloy sheet (JIS A1100-H14) having a thickness of 1.5 mm and a size of 50 mm x 20 mm was prepared. First, the above aluminum alloy sheet was immersed in the aqueous solution for surface treatment at a liquid temperature of 40°C for 1 minute to obtain an alloy sheet from which copper was deposited on the surface. Next, the alloy sheet was sufficiently washed with ion exchange water, and then immersed in the oxidizing agent-acid aqueous solution at a liquid temperature of 40°C until the deposited copper could be removed, and further sufficiently washed with ion exchange water. Thereafter, the alloy sheet from which copper was removed was dried in a warm air drier set at 50°C for 1 hour to obtain a surface-treated alloy. The obtained surface-treated alloy was observed in accordance with the above "Surface observation of alloy". The laser microscope image thereof is shown in Figure 7 In addition, the Spc of the surface of the surface-treated alloy was measured in accordance with the above "Surface roughness measurement of alloy", and the result was 77304 / mm. Further, the tensile strength (bonding strength) between the surface-treated alloy and the PPS resin composition was measured in accordance with the above "Tensile test", and the result was 15 MPa.

[0111] (Example 8)

[0112] An aluminum alloy sheet (JIS A5052-H34) having a thickness of 1.5 mm and a size of 50 mm x 20 mm was prepared. First, the above aluminum alloy sheet was immersed in the aqueous solution for surface treatment at a liquid temperature of 40°C for 1 minute to obtain an alloy sheet from which copper was deposited on the surface. Next, the alloy sheet was sufficiently washed with ion exchange water, and then immersed in the oxidizing agent-acid aqueous solution at a liquid temperature of 40°C until the deposited copper could be removed, and further sufficiently washed with ion exchange water. Thereafter, the alloy sheet from which copper was removed was dried in a warm air drier set at 50°C for 1 hour to obtain a surface-treated alloy. The obtained surface-treated alloy was observed in accordance with the above "Surface observation of alloy". The laser microscope image thereof is shown in Figure 8 In addition, the Spc of the surface of the surface-treated alloy was measured in accordance with the above "Surface roughness measurement of alloy", and the result was 80922 / mm. Further, the tensile strength (bonding strength) between the surface-treated alloy and the PA resin composition was measured in accordance with the above "Tensile test", and the result was 28 MPa.

[0113] (Example 9)

[0114] An aluminum alloy sheet (JIS A5052-H34) having a thickness of 1.5 mm and a size of 50 mm x 20 mm was prepared. First, the above aluminum alloy sheet was immersed in the aqueous solution for surface treatment at a liquid temperature of 40°C for 1 minute to obtain an alloy sheet from which copper was deposited on the surface. Next, the alloy sheet was sufficiently washed with ion exchange water, and then immersed in the oxidizing agent-acid aqueous solution at a liquid temperature of 40°C until the deposited copper could be removed, and further sufficiently washed with ion exchange water. Thereafter, the alloy sheet from which copper was removed was dried in a warm air drier set at 50°C for 1 hour to obtain a surface-treated alloy. The obtained surface-treated alloy was observed in accordance with the above "Surface observation of alloy". The laser microscope image thereof is shown in Figure 9 In addition, the Spc of the surface of the surface-treated alloy was measured in accordance with the above "Surface roughness measurement of alloy", and the result was 80922 / mm. Further, the tensile strength (bonding strength) between the surface-treated alloy and the PA resin composition was measured in accordance with the above "Tensile test", and the result was 28 MPa.

[0115] (Example 10)

[0116] An aluminum alloy sheet (JIS A5052-H34) having a thickness of 1.5 mm and a size of 50 mm x 20 mm was prepared. First, the above aluminum alloy sheet was immersed in the aqueous solution for surface treatment at a liquid temperature of 40°C for 1 minute to obtain an alloy sheet from which copper was deposited on the surface. Next, the alloy sheet was sufficiently washed with ion exchange water, and then immersed in the oxidizing agent / acid aqueous solution at a liquid temperature of 40°C until the deposited copper could be removed, and further sufficiently washed with ion exchange water. Thereafter, the alloy sheet from which copper was removed was dried in a warm air drier set at 50°C for 1 hour to obtain a surface-treated alloy. The obtained surface-treated alloy was observed in accordance with the above "Surface observation of alloy". The laser microscope image thereof is shown in Figure 10 In addition, the Spc of the surface of the surface-treated alloy was measured in accordance with the above "Surface roughness measurement of alloy", and the result was 72764 / mm. Further, the tensile strength (bonding strength) between the surface-treated alloy and the PPS resin composition was measured in accordance with the above "Tensile test", and the result was 26 MPa.

[0117] (Comparative Example 1)

[0118] An aluminum alloy sheet (JIS A5052-H34) having a thickness of 1.0 mm and a size of 50 mm x 20 mm was prepared. First, the above aluminum alloy sheet was immersed in the aqueous solution for surface treatment at a liquid temperature of 40°C for 1 minute. The aluminum alloy sheet was immersed in ion exchange water, and then dried in a warm air drier set at 50°C for 1 hour to obtain a treated alloy. The obtained surface-treated alloy was observed in accordance with the above "Surface observation of alloy". The laser microscope image thereof is shown in Figure 11 In addition, the Spc of the surface of the treated alloy was measured in accordance with the above "Surface roughness measurement of alloy", and the result was 3665 / mm. Further, a composite was attempted to be produced by the same operation as in Example 1 except that the treated alloy was used, but the alloy and the PPS resin composition were not bonded, and no composite was obtained.

[0119] (Comparative Example 2)

[0120] An aluminum alloy sheet (JIS A5052-H34) having a thickness of 1.0 mm and a size of 50 mm x 20 mm was prepared. First, the above aluminum alloy sheet was immersed in the aqueous solution for surface treatment at a liquid temperature of 40°C for 1 minute. The aluminum alloy sheet was immersed in ion exchange water, and then dried in a warm air drier set at 50°C for 1 hour to obtain a treated alloy. The obtained surface-treated alloy was observed in accordance with the above "Surface observation of alloy". The laser microscope image thereof is shown in Figure 12Further, the Spc of the surface of the treated alloy was measured according to the above-described "Surface roughness measurement of alloy", and was 2859 / mm. Furthermore, an attempt was made to produce the composite body in the same manner as in Example 1 except that the treated alloy was used, but the alloy was not joined to the PPS resin composition, and no composite body was obtained.

[0121] (Comparative Example 3)

[0122] An aluminum alloy sheet (JIS A5052-H34) having a thickness of 1.5 mm and a size of 50 mm x 20 mm was prepared. First, the above-described aluminum alloy sheet was immersed in the aqueous solution for surface treatment at a liquid temperature of 40°C for 1 minute to obtain an alloy sheet from which copper was deposited on the surface. Next, the alloy sheet was sufficiently washed with ion exchange water, and then immersed in the oxidizing agent-acid aqueous solution at a liquid temperature of 40°C until the deposited copper could be removed, and further sufficiently washed with ion exchange water. Thereafter, the alloy sheet from which copper was removed was dried in a warm air dryer set to 50°C for 1 hour to obtain a surface-treated alloy. The obtained surface-treated alloy was observed according to the above-described "Surface observation of alloy". The laser microscope image thereof is shown in Figure 13 Further, the Spc of the surface of the surface-treated alloy was measured according to the above-described "Surface roughness measurement of alloy", and was 63252 / mm. Furthermore, an attempt was made to produce the composite body in the same manner as in Example 1 except that the treated alloy was used, but the alloy was not joined to the PPS resin composition, and no composite body was obtained.

[0123] (Comparative Example 4)

[0124] An aluminum alloy sheet (JIS A5052-H34) having a thickness of 1.5 mm and a size of 50 mm x 20 mm was prepared. First, the above-described aluminum alloy sheet was immersed in the aqueous solution for surface treatment at a liquid temperature of 40°C for 1 minute to obtain an alloy sheet from which copper was deposited on the surface. Next, the alloy sheet was sufficiently washed with ion exchange water, and then immersed in the oxidizing agent-acid aqueous solution at a liquid temperature of 40°C until the deposited copper could be removed, and further sufficiently washed with ion exchange water. Thereafter, the alloy sheet from which copper was removed was dried in a warm air dryer set to 50°C for 1 hour to obtain a surface-treated alloy. The obtained surface-treated alloy was observed according to the above-described "Surface observation of alloy". The SEM image thereof is shown in Figure 14 Further, the Spc of the surface of the surface-treated alloy was measured according to the above-described "Surface roughness measurement of alloy", and was 50306 / mm. Furthermore, an attempt was made to produce the composite body in the same manner as in Example 1 except that the treated alloy was used, but the alloy was not joined to the PPS resin composition, and no composite body was obtained.

[0125] (Comparative Example 5)

[0126] An aluminum alloy sheet (JIS A5052-H34) having a thickness of 1.5 mm and a size of 50 mm x 20 mm was prepared. First, the above aluminum alloy sheet was immersed in the aqueous solution for surface treatment at a liquid temperature of 40°C for 1 minute to obtain an alloy sheet from which copper was deposited on the surface. Next, the alloy sheet was sufficiently washed with ion exchange water, and then immersed in the oxidizing agent-acid aqueous solution at a liquid temperature of 40°C until the deposited copper could be removed, and further sufficiently washed with ion exchange water. Thereafter, the alloy sheet from which copper was removed was dried in a warm air drier set at 50°C for 1 hour to obtain a surface-treated alloy. The obtained surface-treated alloy was observed in accordance with the above "Surface observation of alloy". The SEM image thereof is shown in Figure 15 In addition, the Spc of the surface of the surface-treated alloy was measured in accordance with the above "Surface roughness measurement of alloy", and the result was 68587 / mm. Further, an attempt was made to produce a composite body in the same manner as in Example 1 except that the alloy after the treatment was used, but the alloy was not joined with the PPS resin composition, and no composite body was obtained.

[0127] (Comparative Example 6)

[0128] An aluminum alloy sheet (JIS A5052-H34) having a thickness of 1.5 mm and a size of 50 mm x 20 mm was prepared. First, the above aluminum alloy sheet was immersed in the aqueous solution for surface treatment at a liquid temperature of 40°C for 1 minute to obtain an alloy sheet from which copper was deposited on the surface. Next, the alloy sheet was sufficiently washed with ion exchange water, and then immersed in the oxidizing agent-acid aqueous solution at a liquid temperature of 40°C until the deposited copper could be removed, and further sufficiently washed with ion exchange water. Thereafter, the alloy sheet from which copper was removed was dried in a warm air drier set at 50°C for 1 hour to obtain a surface-treated alloy. The obtained surface-treated alloy was observed in accordance with the above "Surface observation of alloy". The SEM image thereof is shown in Figure 16 In addition, the Spc of the surface of the surface-treated alloy was measured in accordance with the above "Surface roughness measurement of alloy", and the result was 68587 / mm. Further, an attempt was made to produce a composite body in the same manner as in Example 1 except that the alloy after the treatment was used, but the alloy was not joined with the PPS resin composition, and no composite body was obtained.

[0129] (Comparative Example 7)

[0130] An aluminum alloy sheet (JIS A5052-H34) having a thickness of 1.5 mm and a size of 50 mm x 20 mm was prepared. First, the above aluminum alloy sheet was immersed in the aqueous solution for surface treatment at a liquid temperature of 40°C for 1 minute to obtain an alloy sheet from which copper was deposited on the surface. Next, the alloy sheet was sufficiently washed with ion exchange water, and then immersed in the oxidizing agent / acid aqueous solution at a liquid temperature of 40°C until the deposited copper could be removed, and further sufficiently washed with ion exchange water. Thereafter, the alloy sheet from which copper was removed was dried in a warm air drier set to 50°C for 1 hour to obtain a surface-treated alloy. The obtained surface-treated alloy was observed in accordance with the above "Surface observation of alloy". The laser microscope image thereof is shown in Figure 17 In addition, the Spc of the surface of the surface-treated alloy was measured in accordance with the above "Surface roughness measurement of alloy", and the result was 52370 / mm. Further, an attempt was made to produce a composite body in the same manner as in Example 1 except that the alloy after the treatment was used, but the alloy and the PPS resin composition were not joined, and a composite body was not obtained.

[0131] [Table 3]

[0132]

[0133] Industrial applicability

[0134] According to the present application, it is possible to provide an aqueous solution for surface treatment of an alloy capable of improving the joining strength of the alloy and a resin composition, a method for producing a surface-treated alloy using the aqueous solution for surface treatment, and a composite body having the surface-treated alloy and a method for producing the same. Therefore, the present application has industrial applicability in the field of surface-treated alloys and composite bodies requiring such characteristics.

Claims

1. An aqueous solution for surface treatment for treating a surface of an alloy, the aqueous solution for surface treatment contains a copper compound having a copper ion concentration of 20,000 ppm or more and 50,000 ppm or less, a heterocyclic nitrogen compound having a concentration of 200 ppm or more and 1,000 ppm or less, and a halide ion having a concentration of 2,000 ppm or more and 70,000 ppm or less, the heterocyclic nitrogen compound is one or more selected from the group consisting of pyrazole, 5-amino tetrazole, and imidazole.

2. The aqueous solution for surface treatment according to claim 1, wherein the copper compound is one or more selected from the group consisting of copper sulfate and copper bromide.

3. The aqueous solution for surface treatment according to claim 1 or 2, wherein, the halide ion is one or more selected from the group consisting of bromide ion and chloride ion.

4. The aqueous solution for surface treatment according to claim 1, wherein, the alloy is an aluminum alloy.

5. A production method of a surface-treated alloy, comprising: a step of bringing the aqueous solution for surface treatment according to any one of claims 1 to 4 into contact with a surface of an alloy; and a step of removing copper, which is deposited on the surface of the alloy in the step of contact, by dissolving or dispersing the copper in an aqueous solution containing an oxidizing agent and an acid, thereby obtaining a surface-treated alloy.

6. The manufacturing method according to claim 5, wherein, the oxidizing agent is a peroxide.

7. The production method according to claim 5 or 6, wherein the acid is an inorganic acid.

8. A composite body comprising: a surface-treated alloy obtained by the production method according to any one of claims 5 to 7, and a resin composition containing a thermoplastic resin, wherein, the resin composition is joined to the surface-treated alloy.

9. A production method of a composite body, comprising: a step of joining a surface-treated alloy obtained by the production method according to any one of claims 5 to 7 to a resin composition containing a thermoplastic resin, thereby obtaining a composite body.

10. The method of manufacturing a composite body according to claim 9, wherein, the production method further comprises, before the step of obtaining the composite body, a step of inserting the surface-treated alloy into a mold, and in the step of obtaining the composite body, a resin composition containing a thermoplastic resin is injected into the mold to be molded, thereby joining the surface-treated alloy to the resin composition.

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