JP7049792B2 - Metal / Resin Composite Structure and Method for Manufacturing Metal / Resin Composite Structure - Google Patents

Description

The present invention relates to a metal / resin composite structure and a method for manufacturing a metal / resin composite structure.

In a wide range of industrial fields centered on the electric and automobile fields, the usefulness of composite technology for integrating a metal such as an iron-based metal or an aluminum-based metal with a thermoplastic resin is increasing.
Conventionally, it has been common to use an adhesive for joining such a metal and a thermoplastic resin. However, the method using an adhesive not only increases the number of production steps, but also may cause the adhesive strength to decrease over time or the bonding strength at high temperatures may not be sufficient. It made it difficult to apply to fields where sex is required. In addition, mechanical joining methods such as screwing have been widely used in the past, but their widespread use has been limited due to reasons such as weight reduction and complicated work processes.

As a new method for joining a metal and a thermoplastic resin, a method of injection molding a thermoplastic resin on a metal member having a roughened surface is known (see, for example, Patent Document 1).
Then, in order to apply the metal-resin composite obtained by such insert molding to the housing of mobile electronic devices, notebook computers, and other parts of mobile devices, the metal surface to which the resin is not bonded is to be applied. It is required to ensure corrosion resistance and weather resistance. Then, such a property is imparted by, for example, an electrolytic oxidation treatment (referred to as "anodizing treatment" when the metal type is an aluminum alloy) (for example, Patent Document 2).

International Publication No. 2015/8847 Japanese Unexamined Patent Publication No. 2007-203585 Japanese Unexamined Patent Publication No. 2001-62862 Japanese Unexamined Patent Publication No. 2016-74116

In the above injection molding, the thermoplastic resin is usually injected and molded after being heated to a temperature showing sufficient fluidity to fill the mold cavity and melted. At this time, the fluidity of the molten resin not only determines the ease of filling into the mold cavity, but also whether the molten resin sufficiently permeates and transfers to the fine uneven portion on the metal surface formed by the surface roughening. It is an important factor that influences.
One of the indicators of resin fluidity is the viscosity of the molten resin. When using high melt viscosity type thermoplastic resins, especially amorphous engineering plastics that are promising from the viewpoint of high strength and high heat resistance, the fluidity at the time of melting is generally inferior, so metal-resin bonding by injection molding In this case, it was necessary to devise a mold temperature control aspect (for example, Patent Document 3).

Conventionally, it has been considered effective to raise the resin temperature and the mold temperature in order to increase the fluidity of the molten resin. However, a high resin temperature and a high mold temperature are disadvantageous in terms of energy and production efficiency, and may cause resin decomposition due to heat to impair the original physical properties of the resin. Various methods for overcoming such problems, such as heat and cool molding methods, have been proposed, but there is a problem that a special mold and temperature control system are required (for example, a patent). Document 4).

On the other hand, the usage environment of electrical and electronic devices composed of mobile electronic device housings and notebook computer housings manufactured by the above-mentioned injection molding method is harsh (for example, long-term use under high temperature and high humidity, heat). As it is used under a cycle), the problem that the bonding force between the metal and the resin decreases with time has become apparent.

Furthermore, in the electrolytic oxidation treatment, when the composite obtained by injection-bonding a resin to the insert metal is subjected to the electrolytic oxidation treatment consisting of anodic oxidation as it is, alkaline etching or a high-concentration inorganic acid which is a pre-stage of anodic oxidation is performed. In the immersion treatment or the anodic oxidation reaction itself, there is a problem that chemical solutions such as alkaline water and acid aqueous solution invade and permeate from the boundary portion between the resin portion and the metal portion, and the bonding force at the boundary portion is reduced. there were.

The present invention has been made in view of the above circumstances, and even when the melt viscosity of the thermoplastic resin constituting the resin member in the metal / resin composite structure is high and the fluidity at the time of melting is inferior, the metal member and the metal member are used. It stably provides a metal / resin composite structure having excellent bonding strength with a resin member.

The present inventors use a method for increasing the bonding strength between a metal member and a resin member in a metal / resin composite structure more than ever, or a thermoplastic resin having a high melt viscosity and poor fluidity at the time of melting. We have been diligently studying to develop a composite structure that exhibits high bonding strength even if it is present. As a result, they have found that a method of interposing a specific metal dendritic layer between a metal member and a resin member is effective, and have reached the present invention.

That is, according to the present invention, the following metal / resin composite structure and a method for manufacturing a metal / resin composite structure are provided.

[1]
A metal member with a fine uneven surface and
A resin member bonded to the fine uneven surface of the metal member and composed of a thermoplastic resin or a resin composition containing the thermoplastic resin.
A metal / resin composite structure comprising:
JIS B0601 (corresponding international standard: ISO4287) for a total of 6 straight sections consisting of any 3 straight sections that are parallel to each other and any 3 straight sections that are orthogonal to the 3 straight sections on the fine uneven surface of the metal member. ), The surface roughness measured in accordance with) meets the following requirements (1) and (2) at the same time.
The surface layer of the fine uneven surface is a metal / resin composite structure containing a dendritic layer .
A metal / resin composite structure in which the average thickness of the dendritic layer measured using an electron microscope is in the range of 190 nm or more and 280 nm or less.
(1) The average value of the ten-point average roughness (Rz) exceeds 5 μm. (2) The average value of the average length (RSm) of the roughness curve elements is in the range of 10 μm or more and 400 μm or less [2].
In the metal / resin composite structure according to the above [1],
A metal / resin composite structure in which the average thickness of the dendritic layer measured using an electron microscope is in the range of 35 nm or more and 700 nm or less.
[3]
In the metal / resin composite structure according to the above [1] or [2],
A metal / resin composite structure having a b * coordinate value in the range of 0 or more and 9 or less in the CIELAB display system measured in accordance with JIS Z8781-4 (2013) on the fine uneven surface of the metal member.
[4]
In the metal / resin composite structure according to any one of the above [1] to [3],
A metal / resin composite structure in which the thermoplastic resin contains an amorphous thermoplastic resin.
[5]
In the metal / resin composite structure according to any one of the above [1] to [4],
The thermoplastic resin is a metal / resin containing one or more selected from polystyrene resin, acrylonitrile-butadiene-styrene resin, polycarbonate resin, polyester resin, modified polyphenylene ether resin, polyether sulfone resin and polyetherimide resin. Composite structure.
[6]
In the metal / resin composite structure according to any one of the above [1] to [5],
The metal member is a metal / resin composite structure containing one or more selected from iron-based metal, aluminum-based metal, magnesium-based metal, copper-based metal, and titanium-based metal.
[7]
The manufacturing method for manufacturing the metal / resin composite structure according to any one of the above [1] to [6].
A metal member having a fine concavo-convex surface is arranged in the mold, and a thermoplastic resin or a resin composition containing the thermoplastic resin is injected into the mold so as to be in contact with the fine concavo-convex surface of the metal member. A method for producing a metal / resin composite structure, which comprises a step of joining the metal member and the resin member by molding a resin member composed of a thermoplastic resin or the resin composition.

According to the present invention, even when the melt viscosity of the thermoplastic resin constituting the resin member in the metal / resin composite structure is high and the fluidity at the time of melting is inferior, the bonding strength between the metal member and the resin member is excellent. It is possible to stably provide a metal / resin composite structure.

It is a schematic diagram which shows an example of the structure of the metal / resin composite structure of embodiment which concerns on this invention. It is a conceptual diagram which shows an example of the cross section of the joint part of the metal / resin composite structure of embodiment which concerns on this invention. It is a figure which shows an example of the SEM photograph of the joint part cross section of the metal / resin composite structure of embodiment which concerns on this invention. It is a figure which shows an example of the Zero-loss TEM photograph of the cross section of the joint part of the metal / resin composite structure of the embodiment which concerns on this invention. A total of 6 straight lines including any 3 straight lines parallel to each other and any 3 straight lines orthogonal to the 3 straight lines on the fine uneven surface of the metal member according to the present invention will be described. It is a schematic diagram for doing. It is a block diagram which shows an example of the process of manufacturing the metal / resin composite structure of embodiment which concerns on this invention schematically.

Hereinafter, embodiments of the present invention will be described with reference to the drawings. In all the drawings, similar components are designated by a common reference numeral, and the description thereof will be omitted as appropriate. Further, the figure is a schematic view and does not match the actual dimensional ratio. Unless otherwise specified, the "~" between the numbers in the text indicates the following from the above.

<Metal / resin composite structure>
The metal / resin composite structure 106 according to the present embodiment will be described.
FIG. 1 is a schematic view showing an example of the structure of the metal / resin composite structure 106 according to the embodiment of the present invention. FIG. 2 is a conceptual diagram showing an example of a cross section of a joint portion of the metal / resin composite structure 106 according to the embodiment of the present invention.
As shown in FIGS. 1 and 2, the metal / resin composite structure 106 is bonded to the metal member 103 having the fine concavo-convex surface 104 and the fine concavo-convex surface 104 of the metal member 103, and is a thermoplastic resin (A). Alternatively, the resin member 105 made of the resin composition (P) containing the thermoplastic resin (A) is provided. The fine uneven surface 104 of the metal member 103 is formed with a fine uneven shape that satisfies the specific requirements (1) and (2) described later. The surface layer of the fine concavo-convex surface 104 includes a dendritic layer 103-1, and in a preferred embodiment, the outermost surface layer of the entire surface layer of the fine concavo-convex surface 104 is composed of the dendritic layer 103-1. In the present embodiment, the "dendritic shape" is defined as a shape like a tree branch, in which a plurality of twigs are entwined.
The metal / resin composite structure 106 according to the present embodiment has the above configuration, so that the thermoplastic resin (A) constituting the resin member 105 in the metal / resin composite structure has a high melt viscosity and fluidity at the time of melting. Even if it is inferior to the above, the bonding strength between the metal member 103 and the resin member 105 can be improved. Further, since the metal / resin composite structure 106 according to the present embodiment is also excellent in electrolytic oxidation resistance, it is possible to reduce, for example, a decrease in bonding strength during anodizing. Further, the metal / resin composite structure 106 according to the present embodiment can reduce the decrease in bonding strength even under high temperature / high humidity environment or heat cycle conditions.

The existence and thickness of the dendritic layer 103-1 can be confirmed by electron microscopic observation of the cross section of the joint portion of the metal / resin composite structure 106. Specifically, cutting out the cross section of the junction by the ion milling method, acquiring a reflected electron image with a scanning electron microscope (SEM), or TEM (transmission electron microscope) or EELS electron beam energy combining this with EELS element mapping. The presence and thickness of the dendritic layer 103-1 can be confirmed by performing loss spectroscopy (TEM-EELS). The average thickness of the dendritic layer 103-1 observed in this way is preferably 35 nm to 700 nm, preferably 40 nm to 500 nm, more preferably 50 nm to 400 nm, still more preferably 50 nm to 300 nm, and particularly preferably 60 nm to. It is in the range of 300 nm. The method for obtaining the average thickness of the dendritic layer 103-1 is not particularly limited, but for example, after cutting out a plurality of joint cross sections of the target metal / resin composite structure 106, the above SEM or the above TEM analysis is performed on each of them. It is obtained by acquiring an image, measuring the width of the dendritic layer 103-1 in the image and averaging them.
FIG. 3 shows a cross-sectional view around the joint portion of the metal / resin composite structure 106 according to the first embodiment, which was observed by SEM analysis. FIG. 4 shows a cross-sectional view around the joint portion of the metal / resin composite structure 106 according to the first embodiment, which was observed by TEM analysis. It can be confirmed that the dendritic layer 103-1 is formed so as to follow the fine uneven shape formed on the surface 110 of the metal member 103.

A fine uneven shape composed of a micron-order uneven shape formed on the fine uneven surface 104 of the metal member 103 and a dendritic layer 103-1 having nano-order gaps formed on the surface layer of the uneven shape. By effectively invading the recesses with the resin composition (P), a physical resistance (anchor effect) is effectively developed between the metal member 103 and the resin member 105, and it is usually difficult to join them. It is considered that the metal member 103 and the resin member 105 made of the resin composition (P) can be firmly bonded to each other. The metal / resin composite structure 106 thus obtained can also prevent moisture and moisture from entering the interface between the metal member 103 and the resin member 105.

Hereinafter, each member constituting the metal / resin composite structure 106 will be described.

(Metal member)
The metal member 103 according to the present embodiment is a metal member having a fine uneven shape on the surface of a joint portion with at least the resin member 105. Here, in the present embodiment, the surface on which the fine uneven shape is formed is also referred to as the fine uneven surface 104. Specifically, the fine concavo-convex surface 104 according to the present embodiment has JIS B0601 (specifically, for a total of 6 straight lines including any 3 straight lines having a parallel relationship and any 3 straight lines orthogonal to the 3 straight lines. The surface roughness measured in accordance with the corresponding international standard: ISO4287) simultaneously satisfies the characteristics of the following requirements (1) and (2).
Requirement (1); The average value of the ten-point average roughness (Rz) exceeds 5 μm, preferably in the range of 7 μm to 30 μm, more preferably 8 μm to 25 μm, and further preferably 10 μm to 20 μm. As the average value of the ten-point average roughness (Rz), the average value of the Rz of any of the six straight lines described above can be adopted.
Requirement (2); The average value of the average length (RSm) of the roughness curve elements is 10 μm to 400 μm, preferably 50 μm to 350 μm, more preferably 70 μm to 330 μm, still more preferably 70 μm to 250 μm, still more preferably 70 μm to. It is in the range of 230 μm. As the average value of the average length (RSm) of the roughness curve elements, the average value of the RSm of any of the above-mentioned 6 straight lines can be adopted.

FIG. 5 is a schematic for explaining a total of 6 straight lines including an arbitrary 3 straight lines having a parallel relationship and an arbitrary 3 straight lines orthogonal to the 3 straight lines on the fine uneven surface 104 of the metal member 103. It is a figure.
For the 6 straight line portions, for example, 6 straight line portions B1 to B6 as shown in FIG. 5 can be selected. First, as the reference line, the center line B1 passing through the center portion A of the fine uneven surface 104 of the metal member 103 is selected. Next, the straight lines B2 and B3 that are parallel to the center line B1 are selected. Next, the center line B4 orthogonal to the center line B1 is selected, and the straight lines B5 and B6 orthogonal to the center line B1 and parallel to the center line B4 are selected. Here, the vertical distances D1 to D4 between the straight lines are, for example, 2 to 5 mm.
Normally, not only the surface of the joint portion in the surface 110 of the metal member 103 but also the entire surface 110 of the metal member 103 is subjected to surface roughening treatment. When the entire surface 110 of the metal member 103 is subjected to surface roughening treatment, a 6-straight line portion may be selected from a portion other than the joint surface on the same surface as the joint surface of the metal member 103. ..

The fine uneven shape formed on the fine uneven surface 104 of the metal member 103 according to the present embodiment satisfies the above requirements (1) and (2), and the surface layer portion of the fine uneven shape is made of metal. / It is composed of a dendritic layer 103-1 whose existence was confirmed by observing the cross section of the resin composite structure 106. That is, the dendritic layer 103-1 interposed between the metal member 103 and the resin member 105 in the metal / resin composite structure 106 according to the present embodiment has fine irregularities of the metal member 103 before joining the resin member 105. It is also present on the surface 104. The dendritic layer 103-1 can be observed even after the resin member 105 is joined.

The resin composition (P) containing the thermoplastic resin (A) penetrates into the finely uneven concave portion via the dendritic layer 103-1. In the present embodiment, the resin composition (P) extends to a region having a depth of 1/2 or more of the average thickness δ of the nano-order gaps (recesses) of the dendritic layer 103-1 constituting the fine uneven shape. It is confirmed by EELS electron beam energy loss spectroscopy (TEM-EELS) that it has penetrated.

The b * coordinate value in the CIELAB display system measured in accordance with JIS Z8781-4 (2013) on the fine uneven surface 104 of the metal member 103 according to the present embodiment is preferably in the range of 0 or more and 9 or less. It is preferably in the range of more than 0 and less than 8, more preferably 1 or more and less than 7, and particularly preferably 1 or more and 6 or less. When the b * coordinates satisfy this range, the bonding strength is reduced even when the metal / resin composite structure 106 is used in a harsh environment, for example, under high temperature conditions, high humidity conditions, or heat cycle conditions. It is possible to further suppress it.

The metal member 103 can be obtained, for example, by processing a metal material (M) and then forming a fine concavo-convex shape on the surface. The type of the metal material (M) is not particularly limited, and for example, iron-based metal (iron, iron alloy, steel material, stainless steel, etc.), aluminum-based metal (aluminum alone, aluminum alloy, etc.), magnesium-based metal (magnesium, Magnesium alloys, etc.), copper-based metals (copper, copper alloys, etc.), titanium-based metals (titanium, titanium alloys, etc.) and the like can be mentioned. These metals may be used alone or in combination of two or more. Among these, aluminum-based metals are preferable, and aluminum alloys are more preferable, because they are lightweight and have high strength.
As the aluminum alloy, alloy numbers 1050, 1100, 2014, 2024, 3003, 5052, 6063, 7075 and the like specified in JIS H4000 are preferably used.

The shape of the metal member 103 is not particularly limited as long as it can be joined to the resin member 105, and may be, for example, a flat plate, a curved plate, a rod, a cylinder, a pipe, a lump, or the like. Further, it may be a structure composed of a combination of these.
The shape of the surface of the joint portion to be joined to the resin member 105 is not particularly limited, and examples thereof include a flat surface and a curved surface.

The metal member 103 is processed into the above-mentioned predetermined shape by plastic working such as cutting or pressing, punching, cutting, polishing, electric discharge machining, etc., and then roughened as described later. Is preferable. In short, it is preferable to use one processed into a required shape by various processing methods.

The finely uneven surface 104 of the metal member 103 according to the present embodiment is obtained by roughening the surface 110 of the metal member 103 using, for example, an etching agent, an anodizing method, a mechanical cutting method, or the like, and then roughening the surface 110 of the metal member 103. It can be formed by treating 110 with warm water.
Here, roughening the surface of a metal member by using an etching agent, anodizing method, mechanical cutting method, or the like has also been performed in the prior art. However, in the present embodiment, the surface of the metal member is roughened by using an etching agent, anodizing method, mechanical cutting method, etc. to form a micron-order uneven shape, and then further treated with warm water. The dendritic layer 103-1 is formed on the surface layer portion of the fine uneven surface 104. That is, in order to obtain the fine uneven surface 104 of the metal member 103 according to the present embodiment, it is important to perform the treatment with warm water in addition to the roughening treatment by an etching agent, anodizing method, mechanical cutting method or the like. Become.
Hereinafter, an example of a method for forming the fine uneven surface 104 of the metal member 103 according to the present embodiment will be shown. However, the method for forming the fine uneven surface 104 of the metal member 103 according to the present embodiment is not limited to the following examples.

The micron-order uneven shape existing at least on the fine uneven surface 104 of the metal member 103 can be formed by a known metal surface roughening method. For example, a chemical solution treatment method; anodizing method; a mechanical cutting method such as sandblasting, knurling, and laser processing can be mentioned. These known methods can be used alone or in combination as appropriate.
Among these known methods, chemical treatment with an acid-based etching agent is preferable. As a known chemical solution treatment method using an acid-based etching agent, for example, the treatment methods disclosed in International Publication No. 2015/8847, Japanese Patent Application Laid-Open No. 2001-3486484, International Publication No. 2008/81933 and the like can be adopted. ..

Further, as a treatment method with hot water performed after the surface 110 of the metal member 103 is roughened, for example, the treatment method disclosed in Japanese Patent Application Laid-Open No. 2008-162115 can be adopted.

In the present embodiment, when the treatment with the zinc ion-containing alkaline aqueous solution is added before the treatment with the acid-based etching agent, the airtightness of the joint surface of the metal / resin composite structure 106 is improved and the surface-roughened metal surface is smoothed. It is preferable because it can prevent a phenomenon in which the property is impaired. For the treatment with the zinc ion-containing alkaline aqueous solution, for example, the treatment method disclosed in International Publication No. 2013/47365 can be adopted.

In the present embodiment, as a specific method for forming a fine uneven shape on the surface 110 of the metal member 103, a process including the following steps (1) to (5), preferably the following steps (1) to An example of the process of performing (5) in this order can be illustrated. Although the process is also adopted in the examples described later, the present invention is not limited to this process.
(1) Pretreatment Step This is a step of removing a film made of an oxide film, a hydroxide, or the like existing on the surface of the metal member 103 on the joint side with the resin member 105. Usually, mechanical polishing or chemical polishing treatment is performed. If the surface of the joint is significantly contaminated with machine oil or the like, it may be treated with an alkaline aqueous solution such as an aqueous solution of sodium hydroxide or an aqueous solution of potassium hydroxide, or degreased.
(2) Treatment step with a zinc ion-containing alkaline aqueous solution In a zinc ion-containing alkaline aqueous solution containing alkali hydroxide (MOH) and zinc ion (Zn ²⁺ ) in a mass ratio (MOH / Zn ²⁺ ) of 1 to 100, the above. This is a step of immersing the treated metal member 103 to form a zinc-containing film on the surface of the metal member.
(3) Treatment step with an acid-based etching agent The metal member 103 after completion of the above step (2) is treated with at least one of ferrous ion and cupric ion and an acid-based etching agent containing an acid to form a metal member. This is a step of elution of the zinc-containing film on the surface of 103 and forming an uneven shape on the order of micron.
(4) Treatment step with warm water Micron-order unevenness formed on the metal member 103 by immersing the metal member 103 after completion of the above step (3) in warm water at 45 ° C. to 95 ° C. for 5 to 30 minutes. This is a step of imparting a dendritic layer having nano-order gaps on the shape.
The temperature of the hot water at the time of the hot water treatment is an important parameter when, for example, anodizing treatment such as anodizing treatment for imparting weather resistance and beautiful decoration to the metal / resin composite structure 106 is performed. That is, when performing such anodizing treatment, it is preferable that the temperature of the hot water is low, specifically, 45 ° C. or higher and 70 ° C. or lower, preferably 45 ° C. or higher and 65 ° C. or lower, and more preferably 45 ° C. or higher 60. The temperature is lower than ° C, particularly preferably 46 ° C or higher and 59 ° C or lower. The time for hot water treatment is usually 5 to 30 minutes. When the temperature of the hot water is relatively low, about 50 ° C., the treatment time is about 15 to 30 minutes, and when the temperature of the hot water is relatively high, about 60 ° C., the treatment time is about 5 to 15 minutes. When the temperature of the hot water satisfies the above range, for example, in the two steps of alkaline etching and chemical polishing during anodizing, a strong basic or strong acid chemical solution melts the metal member from the boundary portion of the metal-resin joint. At the same time, it is possible to more effectively prevent the phenomenon that the joint surface is destroyed and the joint strength is lowered by invading toward the inside.
(5) Post-treatment step This is a cleaning step performed after the above step (4). It usually consists of washing and drying operations. An ultrasonic cleaning operation may be included for smut removal.

In the present embodiment, washing with water is usually performed at the final stage of the step (1), the step (2), and the step (3). The washing with water may be washing with water under ultrasonic irradiation (also referred to as ultrasonic washing). In particular, it is preferable to carry out ultrasonic cleaning at the final stage of the step (3) because the life of the dilute nitric acid used in the next step can be extended.

Further, the metal / resin composite structure 106 of the present embodiment obtained by injection-bonding a resin composition onto a metal member 103 is subjected to a particularly harsh environment (for example, high temperature, high humidity, heat cycle environment, etc.). In order to impart the heat resistance and moisture resistance required for use in the above step (3), it is preferable to carry out the following step (3') after the step (3) is completed and before the step (4) is carried out.
(3') Treatment step with dilute nitric acid The step (3') is a step of washing the metal member 103 after the completion of the step (3) with dilute nitric acid having a concentration of 10 to 40% by mass and then washing with water. It is preferable that the washing with water in this step (3') is carried out to the extent that the yellow component on the metal surface disappears. More preferably, it is washed with water and then washed with water so that the b * coordinate value in the CIELAB display system measured according to JIS Z8781-4 (2013) on the surface of the metal member after drying satisfies the range of 0 or more and 7 or less. Will be done. The specific water washing method for this purpose is not particularly limited, and examples thereof include a method of using ultrasonic waves at the time of washing with water, and a method of vertically and / or horizontally shaking a metal member in a water tank. Can be done.

The present inventors formed micron-order uneven shapes on the surface of the metal member 103 in the process of treating the metal material with the acid-based etching agent, and then nano-ordered on the surface of the metal member 103 in the process of treating with warm water. It is believed that a dendritic layer with gaps is formed.

(Resin member)
Hereinafter, the resin member 105 according to this embodiment will be described.
The resin member 105 is made of a resin composition (P) containing a thermoplastic resin (A). The resin composition (P) contains a thermoplastic resin (A) as a resin component and, if necessary, a filler (B). Further, the resin composition (P) contains other compounding agents as required. For convenience, even when the resin member 105 is made of only the thermoplastic resin (A), it is described that the resin member 105 is made of the thermoplastic resin composition (P).

The thermoplastic resin (A) is not particularly limited, but for example, a polyolefin resin, a polymethacrylic resin such as polymethylmethacrylate resin, a polyacrylic resin such as methylpolyacrylate resin, a polystyrene resin, and a polyvinyl alcohol-polyvinyl chloride. Aromatic poly such as copolymer resin, polyvinyl acetal resin, polyvinyl butyral resin, polyvinyl formal resin, polymethylpentene resin, maleic anhydride-styrene copolymer resin, polycarbonate resin, polyether ether ketone resin, polyether ketone resin, etc. Etherketone, polyester resin, polyamide resin, polyamideimide resin, polyimide resin, polyetherimide resin, styrene-based elastomer, polyolefin-based elastomer, polyurethane-based elastomer, polyester-based elastomer, polyamide-based elastomer, ionomer, aminopolyacrylamide resin, isobutylene anhydrous Maleic acid copolymer, acrylonitrile-butadiene-styrene resin (ABS), ACS, AES, AS, ASA, MBS, ethylene-vinyl chloride copolymer, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-vinyl chloride graft polymer, ethylene-vinyl alcohol Copolymer, chlorinated polyvinyl chloride resin, chlorinated polyethylene resin, chlorinated polypropylene resin, carboxyvinyl polymer, ketone resin, amorphous copolyester resin, norbornen resin, fluoroplastic, polytetrafluoroethylene resin, fluorinated ethylene polypropylene resin , PFA, polychlorofluoroethylene resin, ethylene tetrafluoroethylene copolymer, polyvinylidene fluoride resin, polyvinyl fluoride resin, polyallylate resin, thermoplastic polyimide resin, vinylidene chloride resin, polyvinyl chloride resin, vinyl acetate resin, polysulphon Resin, polyparamethylstyrene resin, polyallylamine resin, polyvinyl ether resin, polyphenylene ether resin, modified polyphenylene ether resin, polyphenylene sulfide (PPS) resin, polymethylpentene resin, oligoester acrylate, xylene resin, maleic acid resin, polyhydroxy Butyrate resin, polysulfone resin, polylactic acid resin, polyglutamic acid resin, polycaprolactone resin, polyethersulfone resin, polyacrylonitrile resin, styrene-acrylonitrile copolymer resin And so on.

In the present embodiment, the thermoplastic resin (A) preferably contains an amorphous thermoplastic resin. For example, a blend (alloy) of an amorphous thermoplastic resin (A ₁ ) and an amorphous thermoplastic resin (A ₂ ) of a different type from the above amorphous thermoplastic resin (A ₁ ); amorphous heat. When a blend (alloy) of a plastic resin (A ₁ ) and a crystalline thermoplastic resin (A ₃ ); or the like is used, the effect according to the present embodiment can be obtained more effectively.
Here, the amorphous thermoplastic resin (A ₁ or A ₂ ) refers to a thermoplastic resin that cannot take a crystalline state or has an extremely low crystallinity even if it is crystallized, and more specifically, it is also called an amorphous polymer. This is a solid state (amorphous) in which atoms or molecules do not form a three-dimensionally regular spatial lattice, but are randomly assembled.
The amorphous state has a glass state and a rubber state, and is a thermoplastic resin having a characteristic of showing a hard glass-like state below the glass transition point (Tg) but a soft rubber-like state above Tg, and is the above-mentioned thermoplastic resin. Within the group, for example, polystyrene resin, ABS, polycarbonate resin, polyester resin, modified polyphenylene ether resin, polyether sulfone resin, polyetherimide resin and the like fall under this category. Such amorphous thermoplastic resins are attracting attention in many industrial fields because they exhibit high strength and high heat resistance.

According to the present embodiment, even when such an amorphous thermoplastic resin or the resin composition (P) containing the above amorphous thermoplastic resin is used, a special heat & cool molding method or the like is used. A metal / resin composite structure 106 having sufficient bonding strength can be obtained without using a molding method. Further, in the method for manufacturing the metal / resin composite structure 106 according to the present embodiment, if a special injection molding method such as heat & cool molding is combined, the bonding strength can be further dramatically improved.

As the constituent component of the resin composition (P), the amorphous thermoplastic resin may be used alone or in combination of two or more as appropriate as described above, or the amorphous thermoplastic resin and the crystalline thermoplastic may be used. Resins may be used in combination as appropriate. When the resin composition (P) contains an amorphous thermoplastic resin, the amount of the amorphous thermoplastic resin is 10% by mass or more, preferably 20% by mass or more, more preferably 20% by mass or more, based on the entire resin composition (P). Is preferably contained in an amount of 30% by mass or more.
Among amorphous thermoplastic resins, modified polyphenylene ether resin (hereinafter, may be abbreviated as m-PPE) or m-PPE having excellent dimensional stability, relatively small molding shrinkage, and low water absorption. A resin composition containing the above is preferable.

The m-PPE according to the present embodiment is preferably at least one selected from polystyrene, high impact polystyrene, syndiotactic polystyrene and rubber-reinforced syndiotactic polystyrene with respect to 100 parts by mass of PPE in a range of 500 parts by mass or less, preferably. It is preferably added in the range of 200 parts by mass or less. The PPE according to this embodiment includes poly (2,6-dimethyl-1,4-phenylene ether), 2,6-dimethylphenol and 2,3,6-trimethyl from the viewpoint of versatility and availability. Copolymers with phenol and the like are preferably used.

Examples of the polyester resin according to the present embodiment include aliphatic polyesters such as polylactic acid, polyglucolic acid, polycaprolactone, and polyethylene succinate, polyethylene terephthalate, polyethylene naphthalate, polybutylene terephthalate (PBT), and polycyclohexylene dimethylene. Examples include terephthalate (PCT).

The thermoplastic resin (A) is one or more selected from polystyrene resin, acrylonitrile-butadiene-styrene resin, polycarbonate resin, polyester resin, modified polyphenylene ether resin, polyether sulfone resin and polyetherimide resin. Is preferable.

(Filler (B))
The resin composition (P) may further contain a filler (B) from the viewpoint of adjusting the difference in linear expansion coefficient between the metal member 103 and the resin member 105 and improving the mechanical strength of the resin member 105.
As the filler (B), for example, one or more kinds can be selected from the group consisting of glass fiber, carbon fiber, carbon particles, clay, talc, silica, mineral, and cellulose fiber. Of these, one or more selected from glass fiber, carbon fiber, talc, and minerals are preferable.

When the resin composition (P) contains the filler (B), the content thereof is preferably 1 part by mass or more and 100 parts by mass or less with respect to 100 parts by mass of the thermoplastic resin (A). It is preferably 5 parts by mass or more and 90 parts by mass or less, and particularly preferably 10 parts by mass or more and 80 parts by mass or less.

(Other compounding agents)
The resin composition (P) may contain other compounding agents for the purpose of imparting individual functions. Examples of such a compounding agent include heat stabilizers, antioxidants, pigments, weather resistant agents, flame retardants, plasticizers, dispersants, lubricants, mold release agents, antistatic agents and the like.

When the resin composition (P) contains other compounding agents, the content thereof is preferably 0.0001 to 5 parts by mass, more preferably 0, with respect to 100 parts by mass of the thermoplastic resin (A). .001 to 3 parts by mass.

(Preparation method of resin composition (P))
The method for preparing the resin composition (P) is not particularly limited, and the resin composition (P) can be prepared by a generally known method. For example, the following method can be mentioned. First, a thermoplastic resin (A), a filler (B) if necessary, and other compounding agents as necessary, and a Banbury mixer, a single-screw extruder, a twin-screw extruder, a high-speed twin-screw extruder, etc. The resin composition (P) is obtained by mixing or melt-mixing using the mixing device of the above.

<Manufacturing method of metal / resin composite structure>
FIG. 6 is a block diagram schematically showing an example of a process of manufacturing the metal / resin composite structure 106 according to the embodiment of the present invention.
In the metal / resin composite structure 106 according to the present embodiment, for example, the metal member 103 having the fine concavo-convex surface 104 is arranged in the mold 102, and the resin composition (P) containing the thermoplastic resin (A) is gold. It can be manufactured by injecting it into the mold 102.
In the injection step, for example, the metal member 103 having the fine uneven surface 104 is inserted into the cavity of the mold 102 for injection molding, and the resin composition (P) is injected so as to be in contact with the fine uneven surface 104 of the metal member 103. This is a step of molding the resin member 105 by the injection molding method to manufacture the metal / resin composite structure 106.
Specifically, first, a mold 102 for injection molding is prepared, the mold 102 is opened, and a metal member 103 is installed in a part thereof. After that, the mold is closed, and the resin composition (P) is injected into the mold so that at least a part of the resin composition (P) is in contact with the fine uneven shape formed on the surface 110 of the metal member 103. And solidify. After that, the metal / resin composite structure 106 can be obtained by opening the mold and releasing the mold.

Further, in the injection molding step, a known injection foam molding or a known heat & cool molding in which the temperature of the mold is controlled in one cycle of the injection molding to heat and cool may be used in combination. As a condition for heat and cool molding, it is desirable to heat the injection molding die to a temperature of 80 ° C. or higher and 300 ° C. or lower, and cool the injection molding die after the injection of the resin composition (P) is completed. The preferred range of the temperature for heating the mold differs depending on the thermoplastic resin (A) constituting the resin composition (P), and if the crystalline resin is a thermoplastic resin having a melting point of less than 200 ° C, it is 80 ° C or higher and 200 ° C or higher. The temperature is preferably 120 ° C. or lower, and 120 ° C. or higher and 300 ° C. or lower is preferable for a thermoplastic resin having a melting point of 200 ° C. or higher as a crystalline resin. In the resin composition containing an amorphous resin, it is preferable to cool the mold to 20 ° C. or higher and 180 ° C. or lower after completing the injection at a temperature equal to or higher than Tg (glass transition temperature) of the resin.

<Use of metal / resin composite structure>
Since the metal / resin composite structure 106 according to the present embodiment has high productivity and a high degree of freedom in shape control, it can be developed into various uses.
Further, since the metal / resin composite structure 106 according to the present embodiment exhibits high airtightness and watertightness, it is suitably used for applications according to these characteristics.

For example, structural parts for vehicles, vehicle-mounted products, housings for electronic devices, housings for home appliances, structural parts, mechanical parts, various automobile parts, parts for electronic devices, battery peripheral parts, furniture, kitchen supplies, etc. Examples include household appliances, medical equipment, building material parts, other structural parts and exterior parts.

More specifically, it is the following component designed so that the metal supports the part where the strength is insufficient with the resin alone. For vehicles, instrument panels, console boxes, doorknobs, door trims, shift levers, pedals, glove boxes, bumpers, bonnets, fenders, trunks, doors, roofs, pillars, seats, radiators, oil pans, steering wheels, Examples thereof include an ECU box, a LIB battery module, a LIB cooling member, and electrical components. Examples of building materials and furniture include glass window frames, handrails, curtain rods, chests of drawers, drawers, closets, bookcases, desks, and chairs. Further, examples of precision electronic components include connectors, relays, gears and the like. Further, examples of the transport container include a transport container, a suitcase, a trunk and the like.

Further, by combining the high thermal conductivity of the metal member 103 and the heat insulating property of the resin member 105, it can be used for parts used in equipment for optimally designing heat management, for example, various home appliances. Specifically, home appliances such as refrigerators, washing machines, vacuum cleaners, microwave ovens, air conditioners, lighting equipment, electric water heaters, TVs, watches, ventilation fans, projectors, speakers, personal computers, mobile phones, smartphones, digital cameras, tablets. Examples thereof include type PCs, portable music players, portable game machines, chargers, electronic information devices such as batteries, and robot members.

The uses of the metal / resin composite structure 106 according to the present embodiment have been described above, but these are examples of the uses of the present invention, and can be used for various uses other than the above.

Although the embodiments of the present invention have been described above, these are examples of the present invention, and various configurations other than the above can be adopted.
Hereinafter, an example of the reference form will be added.
1. 1.
A metal member with a fine uneven surface and
A resin member bonded to the fine concavo-convex surface of the metal member and composed of a thermoplastic resin or a resin composition containing the thermoplastic resin.
A metal / resin composite structure comprising:
JIS B0601 (corresponding international standard: ISO4287) for a total of 6 straight portions consisting of arbitrary 3 straight portions parallel to each other and arbitrary 3 linear portions orthogonal to the 3 straight portions on the fine uneven surface of the metal member. ), The surface roughness measured in accordance with) meets the following requirements (1) and (2) at the same time.
The surface layer of the fine uneven surface is a metal / resin composite structure containing a dendritic layer.
(1) The average value of the ten-point average roughness (Rz) exceeds 5 μm.
(2) The average value of the average length (RSm) of the roughness curve elements is in the range of 10 μm or more and 400 μm or less.
2. 2.
1. 1. In the metal / resin composite structure described in 1.
A metal / resin composite structure in which the average thickness of the dendritic layer measured using an electron microscope is in the range of 35 nm or more and 700 nm or less.
3. 3.
1. 1. Or 2. In the metal / resin composite structure described in 1.
A metal / resin composite structure having a b * coordinate value in the range of 0 or more and 9 or less in the CIELAB display system measured in accordance with JIS Z8781-4 (2013) on the fine uneven surface of the metal member.
4.
1. 1. To 3. In the metal / resin composite structure according to any one of
A metal / resin composite structure in which the thermoplastic resin contains an amorphous thermoplastic resin.
5.
1. 1. To 4. In the metal / resin composite structure according to any one of
The thermoplastic resin is a metal / resin containing one or more selected from polystyrene resin, acrylonitrile-butadiene-styrene resin, polycarbonate resin, polyester resin, modified polyphenylene ether resin, polyether sulfone resin and polyetherimide resin. Composite structure.
6.
1. 1. ~ 5. In the metal / resin composite structure according to any one of
The metal member is a metal / resin composite structure containing one or more selected from iron-based metal, aluminum-based metal, magnesium-based metal, copper-based metal, and titanium-based metal.
7.
1. 1. ~ 6. A manufacturing method for manufacturing the metal / resin composite structure according to any one of the above.
A metal member having a fine concavo-convex surface is arranged in the mold, and a thermoplastic resin or a resin composition containing the thermoplastic resin is injected into the mold so as to be in contact with the fine concavo-convex surface of the metal member. A method for producing a metal / resin composite structure, which comprises a step of joining the metal member and the resin member by molding a resin member composed of a thermoplastic resin or the resin composition.

Hereinafter, this embodiment will be described in detail with reference to Examples and Comparative Examples. The present embodiment is not limited to the description of these examples.

[Example 1]
(Surface roughening process)
An aluminum alloy plate (thickness: 2.0 mm) of alloy number 3003 specified in JIS H4000 was cut into a length of 45 mm and a width of 18 mm. After degreasing the aluminum alloy plate, it is immersed in a treatment tank 1 filled with an alkaline etching agent (30 ° C.) containing 15% by mass of sodium hydroxide and 3% by mass of zinc oxide for 3 minutes (in the following description). After (sometimes abbreviated as "zinc pretreatment"), it was washed with water. Next, the obtained aluminum alloy plate contains an acid-based etching aqueous solution containing 3.9% by mass of ferric chloride, 0.2% by mass of cupric chloride, and 4.1% by mass of sulfuric acid (). In the following description, it may be abbreviated as "chemical solution 1"), and the treatment tank 2 is immersed in the treatment tank 2 at 30 ° C. for 5 minutes and shaken. Then, it was immersed in a 30 mass% nitric acid aqueous solution at 65 ° C. for 5 minutes, and then thoroughly washed with water. In the following description, this acid-based etching agent may be abbreviated as chemical solution 1. Next, the aluminum alloy plate 1 having been surface-treated was obtained by immersing it in a hot water tank at 58 ° C. for 10 minutes, shaking it, ultrasonically cleaning it with running water (in water for 1 minute), and then drying it.

The surface roughness of the obtained surface-treated aluminum alloy plate 1 is measured in accordance with JIS B0601 (corresponding ISO4287) using the surface roughness measuring device "Surfcom 1400D (manufactured by Tokyo Precision Co., Ltd.)". Of the roughness, the ten-point average roughness (Rz) and the average length of the roughness curve elements (RSm) were measured, respectively. As a result, the average value of Rz was 14 μm, and the average value of RSm was 135 μm. The Rz average value and the RSm average value are the averages of the measured values at 6 points where the measurement locations are changed. As shown in FIG. 5, the measurement location was performed on an arbitrary three straight line portion on the fine uneven surface 104 of the metal member 103 and a total of six straight line portions composed of any three straight line portions orthogonal to the straight line portion. It is a thing.
The surface roughness measurement conditions are as follows.
・ Radius of stylus tip: 5 μm
・ Standard length: 0.8 mm
・ Evaluation length: 4 mm
-Measurement speed: 0.06 mm / sec
Further, for the obtained surface-treated aluminum alloy plate 1, 5 points were arbitrarily selected from the roughened surface, and the b * coordinates of the CIELAB display system were measured in accordance with JIS Z8781-4 (2013). The average value was 3.2.

(Injection molding process)
The surface-treated aluminum alloy plate 1 obtained by the above method was installed in a small dumbbell metal insert mold mounted on an injection molding machine J55-AD manufactured by Japan Steel Works. Next, a modified polyphenylene ether (Noryl CN1134; containing 20% by mass of glass fiber) manufactured by SABIC Innovative Plastics Co., Ltd. was placed in the mold as the resin composition (P) at a cylinder temperature (resin temperature) of 280 ° C. and a mold. A metal / resin composite structure was obtained by injection molding under the conditions of a temperature of 100 ° C., an injection primary pressure of 125 to 135 MPa, and a holding pressure of 110 MPa, and injection-bonding the resin member to the surface-treated aluminum alloy plate 1.

FIG. 3 shows an SEM photograph of the cross section of the joint portion of the obtained metal / resin composite structure. According to this, the average thickness of the dendritic layer was calculated to be 210 nm. Further, a Zero-loss TEM photograph of the cross section of the joint portion of the obtained metal / resin composite structure is shown in FIG. The average thickness of the dendritic layer was estimated to be 210 nm as in the case of SEM, and it was confirmed that the nano-order dendritic layer covered the dendritic layer so as to follow the uneven shape on the order of microns. This dendritic layer was also observed in the SEM analysis of the surface of the aluminum alloy plate 1 before injection molding, and its average thickness was 210 nm. In the following Examples and Comparative Examples, the average thickness of the dendritic layer was obtained from the cross-sectional SEM photograph of the metal / resin composite structure unless otherwise specified.

The tensile shear strength measurement test of the joint was carried out on the metal / resin composite structure obtained in the above injection molding step. Specifically, using a tensile tester "Model 1323 (manufactured by Aiko Engineering Co., Ltd.)", a special jig is attached to the tensile tester, and at room temperature (23 ° C), the chuck distance is 60 mm and the tensile speed is 10 mm. The joint strength was measured under the condition of / min. The joint strength (MPa) was obtained by dividing the breaking load (N) by the area of the joint portion between the aluminum alloy plate and the resin member. The bonding strength was 29 MPa. As for the morphology of the fracture surface, only the fracture of the base metal was observed.
The metal / resin composite structure obtained in the above injection molding step is stored in a constant temperature and humidity machine (manufactured by Tokyo Rika Kikai Co., Ltd., EYEL4 "Enviros") maintained at 60 ° C. and 95% RH for 1500 hours. Then, after allowing to cool to room temperature for a whole day and night, the bonding strength was measured by the same method as above. As a result, the bonding strength was 28 MPa.
Further, the metal / resin composite structure obtained in the above injection molding step was set in a heat shock tester (COSMPIA, ES-53L manufactured by Hitachi Appliances, Inc.), and 65 ° C. × 1 hour / -40 ° C. × After 500 cycles of 1 hour were carried out, the bonding strength was measured by the same method as above after allowing to cool to room temperature for a whole day and night. As a result, the bonding strength was 24 MPa.
These results are summarized in Table 1.

[Example 2]
In the surface roughening step of Example 1, instead of the 10-minute immersion / swaying operation in the hot water tank at 58 ° C., the 8-minute immersion / swaying operation in the hot water tank at 60 ° C. was performed, and in the injection molding step. As the resin composition (P), PBT resin (Gelanex 930HL) manufactured by Polyplastics Co., Ltd. is used instead of the modified polyphenylene ether, and the cylinder temperature (resin temperature) is 270 ° C., the mold temperature is 160 ° C., the injection primary pressure is 95 MPa, and the holding pressure is retained. The surface-treated aluminum alloy plate 2 and the metal / resin composite structure were obtained by operating in the same manner as in Example 1 except that the injection molding was performed under the condition of 80 MPa.
Among the surface roughness measured according to JIS B0601 (corresponding ISO4287), the ten-point average roughness (Rz) and the average length of the roughness curve element (RSm) were measured. As a result, the average value of Rz was 15 μm, and the average value of RSm was 143 μm. Moreover, when the cross-sectional SEM analysis of the obtained metal / resin composite structure was performed, it was calculated that the average thickness of the dendritic layer was 230 nm.
As a result of measuring the tensile shear strength and determining the joint strength in the same manner as in Example 1, it was 36 MPa. As for the morphology of the fracture surface, only the fracture of the base metal was observed.
The metal / resin composite structure obtained in the above injection molding step was anodized. (Alumite condition: The above metal / resin composite structure is immersed in an aqueous sodium hydroxide solution (50 g / L) at 55 ° C. for 60 seconds as an alkaline etching step, and then 80% by volume of phosphoric acid and 20% by volume of sulfuric acid are used as a chemical polishing step. The mixture was immersed in a mixed solution at 95 ° C. for 50 seconds, and then immersed in a 60% aqueous nitric acid solution at room temperature for 30 seconds to remove smut. Then, each sample was energized with a sulfuric acid aqueous solution (200 g / L) at 20 ° C. for 40 minutes. The current density of was 1.0 A / dm ³ ). Finally, as a pore-sealing treatment, the mixture was immersed in an aqueous nickel acetate solution at 95 ° C. for 20 minutes, washed with water, and dried by air blow. The bonding strength of the metal / resin composite structure after the alumite treatment was 28 MPa.
These results are summarized in Table 1.

[Example 3]
In the surface roughening step of Example 2, the same as in Example 2 except that the 12-minute immersion and swaying operation in the 55 ° C. hot water tank was performed instead of the 8-minute immersion and swaying operation in the hot water tank at 60 ° C. The operation was performed to obtain a surface-treated aluminum alloy plate 3 and a metal / resin composite structure, respectively.
Among the surface roughness measured according to JIS B0601 (corresponding ISO4287), the ten-point average roughness (Rz) and the average length of the roughness curve element (RSm) were measured. As a result, the average value of Rz was 14 μm, and the average value of RSm was 150 μm. Moreover, when the cross-sectional SEM analysis of the obtained metal / resin composite structure was performed, it was calculated that the average thickness of the dendritic layer was 200 nm.
As a result of measuring the tensile shear strength and determining the joint strength in the same manner as in Example 2, it was 36 MPa. As for the morphology of the fracture surface, only the fracture of the base metal was observed.
The bonding strength of the metal / resin composite structure obtained in the injection molding step after being anodized in the same manner as in Example 2 was measured and found to be 34 MPa.
These results are summarized in Table 1.

[Example 4]
In the surface roughening step of Example 2, the same as that of Example 2 except that the dipping / shaking operation in the hot water tank at 50 ° C. was performed for 24 minutes instead of the 8 minutes immersion / shaking operation in the hot water tank at 60 ° C. The operation was performed to obtain a surface-treated aluminum alloy plate 4 and a metal / resin composite structure, respectively.
Among the surface roughness measured according to JIS B0601 (corresponding ISO4287), the ten-point average roughness (Rz) and the average length of the roughness curve element (RSm) were measured. As a result, the average value of Rz was 12 μm, and the average value of RSm was 165 μm. Moreover, when the cross-sectional SEM analysis of the obtained metal / resin composite structure was performed, it was calculated that the average thickness of the dendritic layer was 250 nm.
As a result of measuring the tensile shear strength and determining the joint strength in the same manner as in Example 2, it was 35 MPa. As for the morphology of the fracture surface, only the fracture of the base metal was observed.
The bonding strength of the metal / resin composite structure obtained in the injection molding step after being anodized in the same manner as in Example 2 was measured and found to be 34 MPa.
These results are summarized in Table 1.

[Example 5]
The surface-treated aluminum alloy plate 5 and the metal / resin composite structure were operated in the same manner as in Example 1 except that the aluminum alloy plate of alloy number 6063 was used instead of the aluminum alloy plate of alloy number 3003 in Example 1. Was obtained respectively.
Among the surface roughness measured according to JIS B0601 (corresponding ISO4287), the ten-point average roughness (Rz) and the average length of the roughness curve element (RSm) were measured. As a result, the average value of Rz was 18 μm, and the average value of RSm was 148 μm. Moreover, when the cross-sectional SEM analysis of the obtained metal / resin composite structure was performed, it was calculated that the average thickness of the dendritic layer was 270 nm.
As a result of measuring the tensile shear strength and determining the joint strength in the same manner as in Example 1, it was 27 MPa. As for the morphology of the fracture surface, only the fracture of the base metal was observed.
These results are summarized in Table 1.

[Example 6]
In the surface roughening step of Example 1, the surface-treated aluminum alloy plate 6 and the metal / resin composite structure were operated in the same manner as in Example 1 except that the water washing operation after immersion in the 30 mass% nitric acid aqueous solution was not performed. Was obtained respectively.
Among the surface roughness measured according to JIS B0601 (corresponding ISO4287), the ten-point average roughness (Rz) and the average length of the roughness curve element (RSm) were measured. As a result, the average value of Rz was 12 μm, and the average value of RSm was 135 μm. Moreover, when the cross-sectional SEM analysis of the obtained metal / resin composite structure was performed, it was calculated that the average thickness of the dendritic layer was 280 nm. Further, with respect to the obtained surface-treated aluminum alloy plate 6, five points were arbitrarily selected from the roughened surface, and the b * coordinates of the CIELAB display system were measured in accordance with JIS Z8781-4 (2013). The average value was 11.7.
As a result of measuring the tensile shear strength and determining the joint strength in the same manner as in Example 1, it was 26 MPa. As for the morphology of the fracture surface, only the fracture of the base metal was observed.
The metal / resin composite structure obtained in the above injection molding step is stored in a constant temperature and humidity chamber for 1500 hours in the same manner as in Example 1, then allowed to cool to room temperature over a day and night, and then joined by the same method as above. The intensity was measured. As a result, the bonding strength was 18 MPa.
Further, the metal / resin composite structure obtained in the injection molding step is subjected to a heat cycle of 500 cycles in a heat shock tester in the same manner as in Example 1, and then allowed to cool to room temperature over a day and night, and then the same as above. The joint strength was measured by the method. As a result, the bonding strength was 5 MPa.
These results are summarized in Table 1.

[Example 7]
In the surface roughening step of Example 1, the same as that of Example 1 except that the 10-minute immersion and swaying operation in the 70 ° C. hot water tank was performed instead of the 10-minute immersion and swaying operation in the hot water tank at 58 ° C. The aluminum alloy plate 7 having been surface-treated was obtained by operation.
Among the surface roughness measured according to JIS B0601 (corresponding ISO4287), the ten-point average roughness (Rz) and the average length of the roughness curve element (RSm) were measured. As a result, the average value of Rz was 9 μm, and the average value of RSm was 142 μm. Next, using the surface-treated aluminum alloy plate 7, an injection molding step was carried out in the same manner as in Example 1 to obtain a metal / resin composite structure. Moreover, when the cross-sectional SEM analysis of the obtained metal / resin composite structure was performed, it was calculated that the average thickness of the dendritic layer was 260 nm.
As a result of measuring the tensile shear strength and determining the joint strength in the same manner as in Example 1, it was 23 MPa. The results are summarized in Table 2.

[Example 8]
In the surface roughening step of Example 1, instead of the chemical solution 1, ferric chloride is contained in an amount of 2.0% by mass, cupric chloride is contained in an amount of 0.1% by mass, and sulfuric acid is contained in an amount of 2.1% by mass. A surface-treated aluminum alloy plate 8 was obtained by operating in the same manner as in Example 1 except that an acid-based etching agent (aqueous solution; may be abbreviated as chemical solution 2 in the following description) was used.
Among the surface roughness measured according to JIS B0601 (corresponding ISO4287), the ten-point average roughness (Rz) and the average length of the roughness curve element (RSm) were measured. As a result, the average value of Rz was 15 μm, and the average value of RSm was 134 μm. Next, using the surface-treated aluminum alloy plate 8, an injection molding step was carried out in the same manner as in Example 1 to obtain a metal / resin composite structure. Moreover, when the cross-sectional SEM analysis of the obtained metal / resin composite structure was performed, it was calculated that the average thickness of the dendritic layer was 190 nm.
As a result of measuring the tensile shear strength and determining the joint strength in the same manner as in Example 1, it was 26 MPa. The results are summarized in Table 2.

[Example 9]
In the surface roughening step of Example 1, the same operation as in Example 1 was performed except that the surface was not immersed in an alkaline etching agent (30 ° C.) containing 15% by mass of sodium hydroxide and 3% by mass of zinc oxide. The surface-treated aluminum alloy plate 9 was obtained. Among the surface roughness measured according to JIS B0601 (corresponding ISO4287), the ten-point average roughness (Rz) and the average length of the roughness curve element (RSm) were measured. As a result, the average value of Rz was 21 μm, and the average value of RSm was 308 μm. Next, using the surface-treated aluminum alloy plate 9, an injection molding step was carried out in the same manner as in Example 1 to obtain a metal / resin composite structure. Moreover, when the cross-sectional SEM analysis of the obtained metal / resin composite structure was performed, it was calculated that the average thickness of the dendritic layer was 220 nm.
As a result of measuring the tensile shear strength and determining the joint strength in the same manner as in Example 1, it was 24 MPa. The results are summarized in Table 2.

[Comparative Example 1]
In the surface roughening step of Example 1, a surface-treated aluminum alloy plate 10 was obtained by the same operation as in Example 1 except that the immersion and shaking operation in a hot water tank at 58 ° C. was not performed for 10 minutes.
Among the surface roughness measured according to JIS B0601 (corresponding ISO4287), the ten-point average roughness (Rz) and the average length of the roughness curve element (RSm) were measured. As a result, the average value of Rz was 15 μm, and the average value of RSm was 135 μm.
Next, using the surface-treated aluminum alloy plate 10, an injection molding step was carried out in the same manner as in Example 1 to obtain a metal / resin composite structure. Moreover, when the cross-sectional SEM analysis of the obtained metal / resin composite structure was performed, no dendritic layer was observed.
As a result of measuring the tensile shear strength and determining the joint strength in the same manner as in Example 1, it was 10 MPa. The results are summarized in Table 2.

[Comparative Example 2]
In the surface roughening step of Example 1, a surface-treated aluminum alloy plate 11 was obtained by the same operation as in Example 1 except that the surface was not immersed in the acid-based etching agent (aqueous solution) and swayed. Among the surface roughness measured according to JIS B0601 (corresponding ISO4287), the ten-point average roughness (Rz) and the average length of the roughness curve element (RSm) were measured. As a result, the average value of Rz was 1 μm, and the average value of RSm was 166 μm. Next, using the surface-treated aluminum alloy plate 11, an injection molding step was carried out in the same manner as in Example 1 to obtain a metal / resin composite structure, but the metal / resin composite structure could not be joined. Moreover, when the SEM observation of the surface of the aluminum alloy plate before joining was performed, it was calculated that the average thickness of the dendritic layer: 100 nm. The results are summarized in Table 2.

101 Injection molding machine 102 Mold 103 Metal member 103-1 Dendrite layer 104 Fine uneven surface 105 Resin member 106 Metal / resin composite structure 107 Gate / runner 110 Surface

Claims (7)

A metal member with a fine uneven surface and
A resin member bonded to the fine concavo-convex surface of the metal member and composed of a thermoplastic resin or a resin composition containing the thermoplastic resin.
A metal / resin composite structure comprising:
JIS B0601 (corresponding international standard: ISO4287) for a total of 6 straight portions consisting of arbitrary 3 straight portions parallel to each other and arbitrary 3 linear portions orthogonal to the 3 straight portions on the fine uneven surface of the metal member. ), The surface roughness measured in accordance with) meets the following requirements (1) and (2) at the same time.
The surface layer of the fine concavo-convex surface is a metal / resin composite structure containing a dendritic layer .
A metal / resin composite structure in which the average thickness of the dendritic layer measured using an electron microscope is in the range of 190 nm or more and 280 nm or less.
(1) The average value of the ten-point average roughness (Rz) exceeds 5 μm (2) The average value of the average length (RSm) of the roughness curve elements is in the range of 10 μm or more and 400 μm or less. In the metal / resin composite structure according to claim 1,
A metal / resin composite structure in which the average thickness of the dendritic layer measured using an electron microscope is in the range of 35 nm or more and 700 nm or less. In the metal / resin composite structure according to claim 1 or 2.
A metal / resin composite structure having a b * coordinate value in the range of 0 or more and 9 or less in the CIELAB display system measured in accordance with JIS Z8781-4 (2013) on the fine uneven surface of the metal member. In the metal / resin composite structure according to any one of claims 1 to 3.
A metal / resin composite structure in which the thermoplastic resin contains an amorphous thermoplastic resin. In the metal / resin composite structure according to any one of claims 1 to 4.
The thermoplastic resin is a metal / resin containing one or more selected from polystyrene resin, acrylonitrile-butadiene-styrene resin, polycarbonate resin, polyester resin, modified polyphenylene ether resin, polyether sulfone resin and polyetherimide resin. Composite structure. In the metal / resin composite structure according to any one of claims 1 to 5.
The metal member is a metal / resin composite structure containing one or more selected from iron-based metal, aluminum-based metal, magnesium-based metal, copper-based metal, and titanium-based metal. A manufacturing method for manufacturing the metal / resin composite structure according to any one of claims 1 to 6.
A metal member having a fine concavo-convex surface is arranged in the mold, and a thermoplastic resin or a resin composition containing the thermoplastic resin is injected into the mold so as to be in contact with the fine concavo-convex surface of the metal member. A method for producing a metal / resin composite structure, which comprises a step of joining the metal member and the resin member by molding a resin member composed of a thermoplastic resin or the resin composition.

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