JP2020157489A - Method for manufacturing metal-resin composite structure and metal-resin composite structure - Google Patents

Abstract

To provide a method for manufacturing a metal-resin composite structure that makes it possible to confirm, in a convenient manner, whether an inorganic particle layer provided on a fine uneven shape surface formed on a metal member is uniform or not when manufacturing the metal-resin composite structure by joining the metal member to a resin member.SOLUTION: A method for manufacturing a metal-resin composite structure 106 comprises a roughening step of forming a roughened surface on a planned surface to be joined with at least a resin member 105 on a surface of a metal member 103, a base treatment step of bringing an inorganic particle dispersion liquid containing inorganic particles and a fluorescent substance into contact with the roughened surface to provide an inorganic particle layer 107, and an injection molding step for forming a resin member joined to the metal member by arranging the metal member after the base treatment step in a mold for injection molding and injecting a molten thermoplastic resin.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for producing a metal-resin composite structure and a metal-resin composite structure.

In a wide range of industrial fields, mainly in the fields of electricity and automobiles, the usefulness of composite technology that integrates metals such as iron-based metals and aluminum-based metals with resins is increasing.
Conventionally, it has been common to use an adhesive for joining such a metal and a resin. However, the method using an adhesive increases the number of production steps. In addition, the adhesive strength may decrease due to changes over time, or the bonding strength may not be developed at high temperatures. For this reason, it has been difficult to apply it to fields where heat resistance is required, such as automobiles. In addition, mechanical joining methods such as screwing have been widely used, but their widespread use has been limited in terms of weight reduction.

As a new method for joining a metal and a resin, a method of injection molding a thermoplastic resin on a metal member having a roughened surface is known (for example, Patent Documents 1, 2 and the like).

International Publication No. 2015/008847 Japanese Unexamined Patent Publication No. 2018-164989

In general injection molding, first, the thermoplastic resin is heated and melted to a temperature at which it has sufficient fluidity to fill the mold cavity, and then the molten resin is injected.
At this time, the fluidity of the molten resin is an important factor that not only determines the ease of filling the mold cavity, but also determines whether or not the molten resin sufficiently penetrates into the surface-roughened portion of the metal. The viscosity of the molten resin can be mentioned as one index showing the fluidity. When using a high melt viscosity type thermoplastic resin, 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 inferior, so when joining metal resin by injection molding, Ingenuity was needed.

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, high resin temperature and high mold temperature are energetically disadvantageous. In addition, the resin may be decomposed by heat, which may impair the original physical properties of the resin.

Various methods have been proposed to overcome these problems. One of them is a heat and cool molding method characterized in that the mold temperature is changed a plurality of times in one cycle of injection molding. The point of this method is to maintain the mold temperature at the time of resin injection above the glass transition temperature of the resin. However, this method requires a special system equipped with a function of alternately flowing a heat medium and a refrigerant through the mold to repeatedly heat and cool the surface of the mold.

The present inventors used a method of increasing the joint strength between the metal member and the resin member in the metal-resin composite structure more than ever, or a thermoplastic resin having a high melt viscosity and poor fluidity at the time of melting. A method described in Patent Document 2 has been found as a method for producing a composite structure that stably exhibits high bonding strength even in some cases.
In the method described in Patent Document 2, an inorganic particle layer is provided on a fine concavo-convex shaped surface formed on a metal member, for example, using an inorganic particle dispersion liquid, and then a resin is injected to form the metal member and the resin member. Is a method of joining.

However, in this method, is a sufficiently uniform inorganic particle layer formed on the normally colorless to white metal member by the similarly colorless to white inorganic particle dispersion (whether there is a portion not formed). Etc.), a special detection method was required to confirm.
For example, the metal surface or cross section on which the inorganic particle layer is formed may be measured with a scanning electron microscope (SEM) to obtain a reflected electron image, or the composition may be confirmed by energy dispersive X-ray analysis (EDS). Was necessary. It takes time and effort to perform such a detection method, and it is difficult to adopt it for quality control and shipping inspection of an actual production line.

The present inventors have diligently studied a method for easily detecting whether or not a sufficiently uniform inorganic particle layer is formed on a metal member without relying on SEM or EDS. As a result, they have found that the method of including a fluorescent substance in the inorganic particle dispersion is effective, and have completed the present invention.
According to the present invention, a method for producing a metal resin composite structure and a metal resin composite structure shown below are provided.

1. 1.
A method for manufacturing a metal-resin composite structure including a resin member and a metal member to be joined to the resin member.
A roughening step of forming a roughened surface on the surface of the metal member at least on a surface to be joined with the resin member.
A base treatment step of contacting an inorganic particle dispersion liquid containing an inorganic particle and a fluorescent substance on the roughened surface to provide an inorganic particle layer.
Includes an injection molding step of arranging the metal member after the base treatment step in an injection molding die and injecting a molten thermoplastic resin to form a resin member joined to the metal member. A method for manufacturing a metal-resin composite structure.
2. 2.
1. 1. The method for manufacturing a metal resin composite structure according to the above.
A method for producing a metal resin composite structure, wherein a fine concavo-convex structure is formed on the roughened surface, and the average value of the height difference between the concave portion and the convex portion is 10 nm to 200 μm.
3. 3.
1. 1. Or 2. The method for manufacturing a metal resin composite structure according to the above.
The thermoplastic resin is a method for producing a metal resin composite structure containing an amorphous thermoplastic resin.
4.
1. 1. ~ 3. The method for producing a metal-resin composite structure according to any one of the above.
The metal member is a method for producing a metal-resin composite structure containing one or more kinds of metals selected from the group consisting of iron-based metals, aluminum-based metals, magnesium-based metals, copper-based metals and titanium-based metals.
5.
1. 1. ~ 4. The method for producing a metal-resin composite structure according to any one of the above.
A method for producing a metal resin composite structure in which the value of the mass of the inorganic particles / the mass of the fluorescent substance in the inorganic particle dispersion is in the range of 1 to 1000.
6.
A metal-resin composite structure including a resin member and a metal member to be joined to the resin member.
At least the surface of the metal member that is joined to the resin member is a roughened surface.
A metal-resin composite structure in which an inorganic particle layer containing inorganic particles and a fluorescent substance is provided between the metal member and the resin member.

According to the present invention, when the inorganic particle layer is provided between the metal member and the resin member, the uniformity and unevenness of the inorganic particle layer are visualized by containing a fluorescent substance in the dispersion liquid for providing the layer. Is possible.
That is, in the present invention, a fluorescent component that can be visualized by fluorescent coloring with a black light or the like is added to the dispersion liquid for providing the inorganic particle layer. Then, when the inorganic particle layer is provided with the dispersion liquid and then irradiated with ultraviolet rays, the portion where the inorganic particle layer is provided is clearly fluorescently colored, and the uniformity and unevenness of the inorganic particle layer can be visualized.

It is an external view which showed an example of the structure of the metal resin composite structure of the embodiment which concerns on this invention. It is sectional drawing which conceptually showed an example of the structure of the joint part of the metal resin composite structure of embodiment which concerns on this invention.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
In all drawings, similar components are designated by a common reference numeral, and description thereof will be omitted as appropriate. All drawings are schematic views, and the dimensional ratios in the drawings do not always match the actual dimensional ratios.
In the specification, the notation of "a to b" in the description of the numerical range indicates a or more and b or less unless otherwise specified. For example, "1 to 5% by mass" means "1% by mass or more and 5% by mass or less".

<Manufacturing method of metal resin composite structure, metal resin composite structure>
FIG. 1 is an external view showing an example of the structure of the metal resin composite structure 106 according to the present embodiment. FIG. 2 is a cross-sectional view conceptually showing an example of the structure of the joint portion of the metal resin composite structure 106 of the embodiment according to the present embodiment.

As shown in FIGS. 1 and 2, the metal-resin composite structure 106 is a resin member bonded to the metal member 103 and the resin composition (P) which is joined to the metal member 103 and contains a thermoplastic resin. An inorganic particle layer 107 provided between the metal member 103 and the resin member 105 and containing the inorganic particles and the fluorescent substance is provided.
The metal member 103 usually has a fine concavo-convex shape 104 at least on the joint surface with the resin member 105. In other words, the joint surface of the surface of the metal member 103 with the resin member 105 is a roughened surface.
The inorganic particle layer 107 is formed so as to cover a part or all of the fine uneven shape 104 (roughened surface) of the metal member 103, and the metal member 103 and the resin member 105 are joined via the inorganic particle layer 107. are doing.

The inorganic particle layer 107 is formed on the formation region of the fine concavo-convex shape 104 so as to follow the fine concavo-convex shape 104. Therefore, it is expected that the three-dimensional shape of the surface of the inorganic particle layer 107 substantially matches the three-dimensional shape of the fine uneven shape 104.

The presence of the inorganic particle layer 107 is usually due to element mapping analysis of metal-resin junction cross-sections, such as excision of the junction cross-section by ion milling, acquisition of reflected electron images by scanning electron microscope (SEM), and energy dispersive type. It can be confirmed by performing X-ray analysis (EDS).
However, by using a fluorescent substance as in the present embodiment, the existence of the inorganic particle layer 107 and its distribution can be inspected and confirmed more easily. For example, the presence of the inorganic particle layer 107 and its distribution can be inspected and confirmed by irradiating the inorganic particle layer 107 with ultraviolet rays after contacting the inorganic particle dispersion with the metal member 103 to form the inorganic particle layer 107.
The inspection / confirmation may be performed visually, or may be automatically performed by an inspection device including a sensor that recognizes fluorescence and an image processing device connected to the sensor.
As the light source of ultraviolet rays, a light source capable of emitting ultraviolet rays having a main wavelength of 200 to 400 nm and a long wavelength can be used. The light source may be, for example, an ultraviolet light emitting diode (ultraviolet LED), or a black light using a fluorescent tube or an incandescent light bulb. Any light source can be used as long as the fluorescent material develops color.

When a fluorescent substance is blended in a dispersion containing inorganic particles, for example, the fluorescent substance molecule becomes an inorganic particle due to the interaction between the polar group of the fluorescent substance molecule and the polar group on the surface of the inorganic particle (for example, silanol group). It is presumed to be coordinated to the surrounding area. As a result, the fluorescent substance molecule is simultaneously present in the place where the inorganic particle is present. Then, by confirming the dispersed state of the fluorescent substance by fluorescence emission, it can be said that the dispersed state of the inorganic particles can be confirmed at the same time.
Further, from the comparison between Examples and Comparative Examples described later, the present inventors consider a case where the fluorescent substance (for example, a fluorescent substance having a polar group) also has a function of improving the dispersibility of the inorganic fine particles in the dispersion liquid. I think there is. That is, it is also considered that the uniform coating property of the inorganic fine particles on the metal member can be improved by using the fluorescent substance.

The metal resin composite structure 106 is manufactured by a step including the following (1) to (3).
(1) Roughing step of forming a roughened surface on at least the surface to be joined with the resin member on the surface of the metal member (2) An inorganic particle dispersion liquid containing inorganic particles and a fluorescent substance is placed on the roughened surface. Base treatment step of providing an inorganic particle layer in contact with the metal member (3) The metal member after the base treatment step is placed in an injection molding die, and a molten thermoplastic resin is injected to and the metal member. Injection molding process to form joined resin members

Preferably, a fine uneven structure is formed on the roughened surface. The average value of the height difference between the concave portion and the convex portion of this structure is 10 nm to 200 μm.
The thermoplastic resin to be injected preferably contains an amorphous thermoplastic resin. More preferably, the thermoplastic resin is amorphous as a whole.
The mass ratio of the inorganic particles to the fluorescent substance (inorganic particles in terms of solid content / fluorescent substance in terms of solid content) in the inorganic particle dispersion is preferably 1 to 1000, more preferably 10 to 500, still more preferably. It is in the range of 20 to 300. This mass ratio substantially corresponds to the mass ratio of the inorganic particles and the fluorescent substance in the inorganic particle layer 107.

In the metal-resin composite structure 106, the resin composition (P) constituting the resin member 105 usually invades the fine uneven shape 104 formed on the surface 110 of the metal member 103, and the metal and the resin are bonded to each other to form a metal. -Obtained by forming a resin interface.
When the resin composition (P) penetrates into the fine uneven shape 104, a physical resistance force (anchor effect) is effectively exhibited between the metal member 103 and the resin member 105. Then, it is considered that the metal and the resin, which are normally difficult to join, are firmly bonded.

In the metal-resin composite structure 106, the infiltration of moisture and moisture into the interface between the metal member 103 and the resin member 105 is suppressed. That is, the airtightness and watertightness of the joint surface of the metal resin composite structure 106 are improved.

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

[Resin member]
The resin member 105 is composed 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) may contain other compounding agents, if necessary.
Hereinafter, for convenience, even when the resin member 105 is composed of only the thermoplastic resin (A), it is described that the resin member 105 is composed of the thermoplastic resin composition (P).

(Thermoplastic resin (A))
The thermoplastic resin (A) is not particularly limited. For example, polyolefin resin, polymethacrylic resin such as polymethylmethacrylate resin, polyacrylic resin such as methylpolyacrylate resin, polystyrene resin, polyvinyl alcohol-polyvinyl chloride copolymer resin, polyvinyl acetal resin, polyvinyl butyral. Aromatic polyether ketones such as resins, polyvinyl formal resins, polymethylpentene resins, maleic anhydride-styrene copolymer resins, polycarbonate resins, polyether ether ketone resins, polyether ketone resins, polyester resins, polyamide resins, 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 anhydride 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, norbornene resin, fluoroplastic, polytetrafluoroethylene resin, fluorinated ethylene polypropylene resin, PFA, polychlorofluoroethylene resin, Ethylene tetrafluoroethylene copolymer, polyvinylidene fluoride resin, vinyl fluoride resin, polyarylate resin, thermoplastic polyimide resin, vinylidene chloride resin, polyvinyl chloride resin, vinyl acetate resin, polysulfone resin, polyparamethylstyrene resin, poly Allylamine resin, polyvinyl ether resin, polyphenylene ether resin (PPE), modified polyphenylene ether resin (m-PPE), polyphenylene sulfide (PPS) resin, polymethylpentene resin, oligoester acrylate, xylene resin, maleic acid resin, polyhydroxybuty Examples thereof include rate resin, polysulfone resin, polylactic acid resin, polyglutamic acid resin, polycaprolactone resin, polyethersulfone resin, polyacrylonitrile resin, styrene-acrylonitrile copolymer resin and the like. ..

The thermoplastic resin (A) preferably contains an amorphous thermoplastic resin.
For example, a blend (alloy) of an amorphous thermoplastic resin (A1) and an amorphous thermoplastic resin (A2) different from the amorphous thermoplastic resin (A1); an amorphous thermoplastic resin (alloy). When a blend (alloy) of A1) and a crystalline thermoplastic resin (A3) is used, the effect according to the present embodiment can be obtained more effectively.
Here, the amorphous thermoplastic resin (A1 or A2) refers to a thermoplastic resin that cannot take a crystalline state or has an extremely low crystallinity even if it is crystallized. Amorphous thermoplastic resins, more specifically called amorphous polymers, are solid states (amorphous) in which atoms or molecules are irregularly assembled without forming a three-dimensionally regular spatial lattice. is there.
The amorphous state of the amorphous thermoplastic resin includes a glass state and a rubber state. Below the glass transition point (Tg), it shows a hard glass-like state, but above Tg, it shows a soft rubber-like state. Among the above-mentioned thermoplastic resin groups, for example, polystyrene, ABS, polycarbonate resin, modified polyphenylene ether, polyether sulfone, polyetherimide and the like correspond to amorphous thermoplastic resins. Amorphous thermoplastic resin is a resin attracting attention in many industrial fields because it exhibits high strength and high heat resistance. However, in metal-resin integrated bonding in which a fine uneven shape is formed on the metal surface and the resin is physically bonded to the metal by an anchor effect, the resin is sufficiently formed into the fine uneven shape due to its high melt viscosity and low fluidity. It was difficult to invade the resin, and we had to rely on special molding methods such as heat and cool molding.

According to the present embodiment, a metal resin composite structure 106 having sufficient bonding strength is used by using a high melt viscosity type resin or resin composition without using a special molding method such as a heat & cool molding method. Can be obtained. Further, it is considered that the bonding strength can be further dramatically improved by combining a special injection molding method such as heat & cool molding.

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

m-PPE is at least one selected from polystyrene, high-impact polystyrene, syndiotactic polystyrene and rubber-reinforced syndiotactic polystyrene with respect to 100 parts by mass of polyphenylene ether in a range of 500 parts by mass or less, preferably 200 parts by mass. It is preferable that the amount is added in the range of parts or less. As the polyphenylene ether, from the viewpoint of versatility and availability, poly (2,6-dimethyl-1,4-phenylene ether), 2,6-dimethylphenol and 2,3,6-trimethylphenol are copolymerized. A polymer or the like is preferably used.

(Filler (B))
The resin composition (P) may further contain a filler (B) in order to adjust the difference in linear expansion coefficient between the metal member 103 and the resin member 105, improve the mechanical strength of the resin member 105, and the like.
Examples of the filler (B) include one or more types from the group consisting of glass fibers, carbon fibers, carbon particles, clay, talc, inorganic substances, minerals, and cellulose fibers. Of these, one or more selected from glass fiber, carbon fiber, talc, and minerals are preferable.

The shape of the filler (B) is not particularly limited. The shape may be any shape such as a fibrous shape, a particle shape, and a plate shape.
The filler (B) preferably has a filler having a maximum length in the range of 10 nm to 600 μm in a fraction of 5 to 100%. The maximum length is more preferably 30 nm to 550 μm, still more preferably 50 nm to 500 μm. The fraction of the filler (B) in the maximum length range is preferably 10 to 100%, more preferably 20 to 100%.
When the maximum length of the filler (B) is within the above range, the filler (B) can move relatively easily in the thermoplastic resin (A) melted during molding of the resin composition (P). .. Therefore, when the metal resin composite structure 106 is manufactured, the filler (B) can be present in the vicinity of the surface of the metal member 103 at a certain ratio. Then, the resin that interacts with the filler (B) enters the inorganic particle layer 107 on the region where the fine uneven shape 104 is formed on the surface of the metal member 103, so that a stronger bonding strength can be obtained.

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

(Other compounding agents)
The resin composition (P) may contain other compounding agents. Examples thereof 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 0.001 to 1 part by mass with respect to 100 parts by mass of the thermoplastic resin (A). It is 3 parts by mass.

The resin member 105 is obtained by injection molding the resin composition (P). The metal resin composite structure 106 can be obtained by arranging the metal member 103 after the base treatment step in the injection molding die and injecting the molten resin composition (P) into the die. ..
Specifically, first, a mold for injection molding is prepared, the mold is opened, and the metal member 103 after the base treatment step is installed inside. 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 inorganic particle layer 107 formed on the surface 110 of the metal member 103. .. After cooling, the metal resin composite structure 106 can be obtained by opening the mold and releasing the mold.

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

[Metal member]
The metal member 103 has a fine uneven shape 104 at least at a joint with the resin member 105. The fine uneven shape 104 can be formed by various roughening methods described later.
Depending on the type of roughening method, the uneven shape of the region including the fine uneven shape 104 is a relatively large scale first uneven shape portion and a relatively small scale formed on the surface of the first uneven shape portion. It may be composed of the second uneven shape portion of the above.
The fine concavo-convex shape 104 in the present embodiment includes a mode having only the first concavo-convex shape portion, a mode having only the second concavo-convex shape portion, and a mode having both the first concavo-convex shape portion and the second concavo-convex shape portion. Used as.

The depth of the concave portion of the fine uneven shape 104, that is, the average value of the height difference between the convex portion and the concave portion of the fine uneven shape 104 is not particularly limited. This value is, for example, 10 nm to 200 μm. The average value of the height difference is largely determined by the method of roughening the metal surface and its conditions. For example, it can be set to 10 nm to 100 μm by the chemical solution method described later, and 100 to 200 μm by laser processing.
In the present embodiment, the average value of the height difference is synonymous with the ten-point average roughness (Rz _jis ) measured according to JIS B0601: 2001.

The fine concavo-convex shape 104 is preferably, for example, a fine concavo-convex shape in which convex portions having an interval period of 5 nm to 500 μm are forested.
The interval period of the fine uneven shape is an average value of the distances from the convex portion to the adjacent convex portion, and can be obtained by using a photograph taken with an electron microscope or a laser microscope or a surface roughness measuring device.

The interval period measured by an electron microscope or a laser microscope is usually 500 nm or less. Specifically, the interval period can be measured by the following procedure.
First, the surface of the joint portion (planned joint surface) of the metal member 103 is photographed. Next, 50 arbitrary convex portions are selected from the obtained photographs, and the distances from the convex portions to the adjacent convex portions are measured respectively. Then, the interval period is defined as the sum of all the distances from the convex portion to the adjacent convex portion and dividing by 50.

On the other hand, the interval period exceeding 500 nm is obtained by using a surface roughness measuring device. The required period is synonymous with the average length (RSm) of the roughness curve elements measured in accordance with JIS B0601: 2001.

Normally, in the metal member 103, not only the joint portion but also the entire surface of the metal member 103 is roughened. Therefore, the interval period may be measured at a position other than the joint surface on the same surface as the joint surface of the metal member 103.

The interval period is preferably 10 nm to 300 μm, more preferably 20 nm to 200 μm.
When the interval period is 10 nm or more, the resin composition constituting the resin member 105 can sufficiently penetrate into the concave portion having a fine uneven shape, and the bonding strength between the metal member 103 and the resin member 105 can be further improved. Can be done.
When the interval period is 300 μm or less, it is possible to suppress the formation of a gap at the joint portion between the metal member 103 and the resin member 105. As a result, it is possible to prevent impurities such as water from entering through the gap at the interface between the metal member 103 and the resin member 105. As a result, when the metal resin composite structure 106 is used under high temperature and high humidity, it is possible to suppress a decrease in strength.

The resin composition (P) containing a thermoplastic resin usually penetrates into the concave portion of the fine uneven shape 104 via the inorganic particle layer 107. In the present embodiment, it is preferable that the resin composition (P) penetrates into the recess to a depth of 1/2 or more of the depth d of the recess. That is, it is preferable that the penetration depth D of the resin composition (P) into the recess satisfies D ≧ d / 2.

The metal member 103 can be obtained, for example, by processing a metal material (M) and then forming a fine concavo-convex shape 104 on the surface.
The type of metal material (M) is not particularly limited. For example, iron-based metals (iron, iron alloys, steel materials, stainless steel, etc.), aluminum-based metals (aluminum, aluminum alloys, etc.), magnesium-based metals (magnesium, magnesium alloys, etc.), copper-based metals (copper, copper alloys, etc.) ), Titanium-based metal (titanium, titanium alloy) and the like. These metals may be used alone or in combination of two or more.

As for the metal, the most suitable one may be selected according to the application.
For example, in applications where light weight is important, such as a notebook computer housing, aluminum-based metals such as alloy numbers 1050, 2014, 3003, 5052, 6063, and 7075 specified in JIS H4000, or AZ91, AZ80. , AZ91D, AS21 and other magnesium-based metals can be preferably used.
As another example, in applications where mechanical properties are important, such as automobiles, rolled mild steel typified by SPCC, SPHC, SAPH, SPFH, and iron-based metals typified by stainless steel can be 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. The shape can be, for example, a flat plate, a curved plate, a rod, a cylinder, a lump, or the like. Further, the structure may be a combination of these.
The shape of the surface of the joint portion to be joined with the resin member 105 is not particularly limited, and is, for example, a flat surface, a curved surface, or the like.

The metal member 103 is a metal material that has been roughened (described later) after being processed into a predetermined shape by plastic working such as cutting or pressing, punching, cutting, polishing, electric discharge machining, or the like. Is preferable. In short, the metal member 103 processed into a desired shape by an arbitrary processing method can be used.

The fine uneven shape 104 existing on the surface of the joint portion of the metal member 103 with at least the resin member 105 can be formed by a known metal surface roughness method.
For example, a chemical treatment method; an anodic oxidation method; a mechanical cutting method such as sandblasting, knurling, and laser processing can be mentioned. Examples of the chemical treatment method include a method using an acid-based etching agent (International Publication No. 2015/008847, JP-A-2001-348864, International Publication No. 2008/81933, etc.), hydrated hydrazine, ammonia, and water solubility. A method of treating with one or more amine-based aqueous solutions selected from amine compounds (International Publication No. 2009/31632, JP-A-2005-119005, etc.), a method of using a copper surface treatment agent containing an acid, a benzimidazole compound and water. (Patent No. 4242915, etc.), a method of treating with an inorganic acid after applying a metal plating layer (International Publication No. 2016/171128), and the like can be exemplified. Among these, the chemical treatment method is preferable from the viewpoint of etching speed and economy.

[Inorganic particle layer]
The inorganic particle layer 107 contains inorganic particles and a fluorescent substance.
Regarding the amount ratio of the inorganic particles to the fluorescent substance in the inorganic particle layer 107, the mass ratio of the inorganic particles to the fluorescent substance (inorganic particles / fluorescent substance) is preferably 1000 or less. As a result, the inorganic particle layer 107 contains a sufficient amount of fluorescent substance, and sufficient fluorescence can be observed by irradiation with ultraviolet rays. That is, it is possible to inspect whether or not the inorganic particle layer 107 is properly formed.
Further, by setting the mass ratio of the inorganic particles to the fluorescent substance (inorganic particles / fluorescent substance) to 1 or more, the content of the inorganic particles becomes sufficiently large, and it is easy to suppress a decrease in the bonding strength of the metal resin composite structure 106.
The preferable range of the mass ratio of the inorganic particles to the fluorescent substance (inorganic particles / fluorescent substance) is 5 to 300, more preferably 10 to 100.

Hereinafter, specific embodiments of the inorganic particles and the fluorescent substance contained in the inorganic particle layer 107 will be described.

(Inorganic particles)
The average particle size of the primary particles of the inorganic particles is preferably 1 to 100 nm, more preferably 1 to 70 nm, still more preferably 1 to 50 nm, particularly preferably 1 to 30 nm, and particularly preferably more than 1 nm and less than 20 nm.
The inorganic particles may include a secondary particle structure in which a plurality of (several to several hundred) primary particles are aggregated.
The average particle size of the inorganic particles contained in the inorganic particle layer 107 can be measured, for example, by a cross-sectional electron microscope (TEM or SEM) at the joint between the metal member 103 and the resin member 105.

When the average particle size of the inorganic particles is 1 nm or more, it is possible to suppress a decrease in workability due to aggregation of the inorganic particles in the dispersion liquid used when forming the inorganic particle layer 107.
Since the average particle diameter of the inorganic particles is 100 nm or less, it is easy to increase the bonding strength even when the average height difference between the concave and convex portions of the fine uneven shape 104 on the metal member 103 is small (on the order of nm). ..
The average particle diameter of the primary particles of the inorganic particles is preferably smaller than the average height difference between the concave and convex portions of the fine uneven shape 104 on the metal member 103.

The inorganic particle layer 107 is, for example, a layer formed by aggregates (secondary particles) of inorganic particles. The average thickness (β) of the inorganic particle layer 107 is preferably 1 to 400 nm, more preferably 1 to 300 nm, still more preferably 1 to 250 nm, particularly preferably more than 1 nm and less than 200 nm, and particularly preferably 2 to 100 nm.
The average thickness (β) of the inorganic particle layer 107 is measured from, for example, observing the cross section of the joint portion of any three points of the metal resin composite structure 106 using SEM / EDS and obtaining each SEM / EDS image. A value obtained by averaging the thicknesses to be obtained can be adopted.
When the average thickness (β) of the inorganic particle layer 107 is within the above range, the bonding strength of the metal resin composite structure 106 tends to be further improved.
The average thickness (β) of the inorganic particle layer 107 is preferably thinner than the average height difference between the concave and convex portions of the fine uneven shape 104 on the metal member 103.

The inorganic particles contained in the inorganic particle layer 107 are not particularly limited. For example, silica particles, tin oxide particles, nanodiamond particles, zirconia particles, niobium oxide particles, iron oxide particles, alumina particles, carbon nanofibers and the like can be used. Among these, silica particles are preferable.
The inorganic particle layer 107 can contain one or more inorganic particles.

When the inorganic particle layer 107 contains silica particles, the content of the inorganic particles other than the silica particles is, for example, 60% by mass or less, preferably 50% by mass or less, based on 100% by mass of the entire inorganic particle layer 107. It is preferably 30% by mass or less, and particularly preferably 10% by mass or less.

(Fluorescent substance)
As the fluorescent substance, it is preferable to use a fluorescent substance that emits light when irradiated with ultraviolet rays and is colorless when not irradiated with ultraviolet rays. This enables measurement without coloring inorganic particles or metal members.

The fluorescent substance preferably contains at least one compound having a skeleton according to any one of the following general formulas (1) to (3). As the fluorescent substance, a compound in which a polar group such as a hydroxyl group, an ester group, an amino group, an amide group, a carbonyl group, or an acid anhydride group is substituted in these main skeletons is more preferably used.

In addition to the above-mentioned fluorescent substances, examples of fluorescent substances include diphenylethylene-based, oxazole-based, oxadiazole-based, thiazole-based, isothiazole-based, imidazole-based, imidazolone-based, naphthalimide-based, triazole-based, and pyrazole-based. Compounds such as pyrazolone-based, furan-based, thiophene-based, carbostyryl-based, and peridicarboxylic acid amide-based compounds can be included.

A commercially available product may be used as the fluorescent substance. For example, the Fluorine series manufactured by Spectoronics, the Uvitex (registered trademark) series manufactured by BASF, the Tinopal series and the Tinosorb series (Roich marker series manufactured by Shinroihi Co., Ltd., UV-1, LSI-1067 manufactured by Stefan Coupets, etc.) BRY-10 series, Photoine CBUS series from HICKSON, Mikephor series from Mitsui Chemicals, Shining CF series from Shenyang Kako, Blancophor series from Blancophor Fluor, Syno White CBB series from Keijin, 3VSi , One or more of fluorescent substances or fluorescent whitening agents such as Sumitomo Chemical's Whitex WS series can be used.

The inorganic particle layer 107 can be formed by bringing an inorganic particle dispersion liquid containing inorganic particles and a fluorescent substance into contact with a portion (roughened surface) of the metal member 103 having at least a fine concavo-convex shape 104.

The method for preparing the inorganic particle dispersion is not particularly limited. For example, it can be prepared by appropriately mixing the above-mentioned inorganic particles and fluorescent substance in the presence of water, an organic solvent or the like (specifically, water, methanol, ethanol, etc.). Alternatively, the inorganic particle dispersion may be prepared by mixing the dispersion of the inorganic particles with the dispersion or solution of the fluorescent substance. In addition, it may be prepared by blending a solid fluorescent substance in a dispersion of inorganic particles.

The specific method (specific method of the base treatment step) for providing the inorganic particle layer 107 by bringing the inorganic particle dispersion liquid into contact with the roughened surface is not particularly limited. For example, the inorganic particle layer 107 can be provided by immersing the metal member 103 on which the fine uneven shape 104 is formed in an inorganic particle dispersion liquid and then drying the metal member 103.
Alternatively, the inorganic particle layer 107 may be provided by bringing the inorganic particle dispersion liquid into contact with the metal member 103 by coating or spraying, and then drying the metal member 103. Specific methods for coating and spraying include a bar coat, a spin coat, and a method using a spray gun. The drying may be natural drying or forced drying.

[Use of metal resin composite structure]
The metal resin composite structure according to the present embodiment can be developed for various purposes. In particular, in terms of high airtightness and watertightness, it is suitably used for applications according to these characteristics.

Suitable applications include, 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, furniture, kitchens. Examples include applications for household appliances such as supplies, medical equipment, parts for building materials, other structural parts and exterior parts.

As described above, when the inorganic particle layer is provided on the roughened surface of the metal member, by including a fluorescent substance in the dispersion liquid for forming the inorganic particle layer, the uniformity and unevenness of the inorganic particle layer can be easily improved. You can look it up in. As a result, in manufacturing the metal-resin composite structure, it is possible to improve the yield and reduce the cost.
For example, (1) first, between the base treatment step and the injection molding step, the inorganic particle layer is exposed to ultraviolet rays to confirm the state of the inorganic particle layer, and (2-1) a sufficiently uniform inorganic particle layer is formed. If so, the injection molding process is performed, and (2-2) if the inorganic particle layer is uneven or the inorganic particle layer is uneven, the injection molding process is not performed, so that the yield is achieved. It is possible to improve the above, and it is possible to suppress the consumption of the resin composition (P).

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, the present 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>
(Roughening process (etching))
A surface-treated aluminum alloy plate on which a roughened surface was formed was obtained by the following procedures (1) to (4).
(1) An aluminum alloy plate (45 mm × 18 mm × 2 mm) having an alloy number 3003 specified in JIS H 4000 was degreased.
(2) Surface treatment by immersing the degreased aluminum alloy plate in a treatment tank 1 filled with an alkaline etching agent (30 ° C.) containing 19% by mass of sodium hydroxide and 3% by mass of zinc oxide for 2 minutes. After that, it was washed with water.
(3) The aluminum alloy plate after washing with water was filled with an acid-based etching aqueous solution containing 4.1% by mass of sulfuric acid, 3.9% by mass of ferric chloride, and 0.2% by mass of cupric chloride. It was immersed in the treatment tank 2 at 30 ° C. for 5 minutes. Then, the aluminum alloy plate was shaken for etching.
(4) The aluminum alloy plate was taken out from the treatment tank 2, ultrasonically washed (in water for 1 minute), and then immersed in a 30 mass% nitric acid aqueous solution at 65 ° C. for 5 minutes. Then, the aluminum alloy plate was taken out from the aqueous nitric acid solution, thoroughly washed, and dried.

Regarding the surface texture of the obtained surface-treated aluminum alloy plate, among the surface roughness measured in accordance with JIS B 0601: 2001 (corresponding ISO4287), the average value of the ten-point average roughness (Rz _jis ) and the average value The average value of the average length (RSm) of the roughness curve elements was obtained.
The average value of Rz _jis was 25 μm, and the average value of RSm was 122 μm.
("Average value" means the average value of 6 points at different measurement locations.)

The surface texture measuring device and measuring conditions are as follows.
-Device: Surface roughness measuring device "Surfcom 1400D" (manufactured by Tokyo Seimitsu Co., Ltd.)
・ Radius of stylus tip: 5 μm
・ Standard length: 0.8 mm
・ Evaluation length: 4 mm
-Measurement speed: 0.06 mm / sec

(Base treatment process)
First, the following inorganic particle-containing liquid and fluorescent substance-containing liquid were prepared.
-Inorganic particle-containing liquid: Inorganic-containing primer PM-S manufactured by Japan Nanocoat Co., Ltd. (composition: 79% by mass of methanol, 20% by mass of water, 0.1% by mass of tin oxide, 0.5% by mass of silicon dioxide)
-Fluorescent substance-containing liquid: Water-soluble fluorescent substance WD-801 manufactured by Spectronics of the United States (fluorescent dye 15% by mass, non-ionized water 85% by mass)

The above two liquids were mixed so that the mass ratio of the inorganic particles and the fluorescent dye (inorganic particles as solid content / fluorescent substance as solid content) was 30. As a result, an inorganic particle dispersion liquid for forming an inorganic particle layer was prepared.
The color of the inorganic nanodisperse after the addition of the fluorescent substance was colorless and transparent as before the addition.

Next, the surface-treated aluminum alloy plate obtained in the roughening step was immersed in an inorganic particle dispersion for forming an inorganic particle layer at room temperature for 5 minutes at room temperature. Then, the plate was taken out and dried at 100 ° C. for 20 minutes.

The dried aluminum alloy plate was irradiated with ultraviolet rays in a dark place. Then, it was clearly confirmed that the portion immersed in the inorganic particle dispersion liquid exhibited vivid fluorescent emission as a whole. From this, it was possible to easily confirm that the inorganic particles were distributed almost uniformly over the entire aluminum alloy plate.

(Injection molding process)
A small dumbbell metal insert obtained by mounting a surface-treated aluminum alloy plate on which an inorganic particle layer is formed, obtained through the above surface roughening step and surface treatment step, on an injection molding machine J55-AD manufactured by Japan Steel Works. Installed in the mold.

Next, the melt of the resin composition (P) shown below was injection-molded in the mold under the following injection molding conditions. As a result, the resin member was injection-bonded to the surface-treated aluminum alloy plate on which the inorganic particle layer was formed to obtain a metal-resin composite structure.
[Resin composition (P)]
Modified polyphenylene ether manufactured by Savik Innovative Plastics (Noril ™ CN1134, containing 20% by mass of glass fiber)
[Injection molding conditions]
・ Cylinder temperature (resin temperature) 270 ° C
・ Mold temperature 110 ℃
・ Injection speed 40 mm / sec
・ Holding pressure 90MPa
・ Holding time 10 seconds

(Evaluation)
With respect to the metal-resin joint structure obtained in the above injection molding step, the tensile shear strength of the joint was determined by a tensile test.
Specifically, a tensile tester "Model 1323 (manufactured by Aiko Engineering Co., Ltd.)" is used, a special jig is attached to the tensile tester, and at room temperature (23 ° C), the distance between chucks is 60 mm and the tensile speed is 10 mm / The joint strength was measured under the condition of min. The joint strength was obtained by dividing the breaking load by the area of the joint portion between the aluminum alloy plate and the resin member. The bonding strength was 25 MPa.
Moreover, when the fracture surface of the fractured structure was observed by the tensile test, interfacial fracture and base metal fracture were mixed. The presence of base metal fracture indicates that the bonding force at the metal-resin interface was sufficiently large.

<Comparative example 1>
A surface-treated aluminum alloy plate on which the inorganic particle layer was formed was prepared in the same manner as in Example 1 except that no fluorescent substance was added to the inorganic particle dispersion.
The obtained aluminum alloy plate was irradiated with ultraviolet rays in a dark place, but no light emission was observed, and it was not possible to confirm whether or not the inorganic particle layer was uniformly formed.

In Comparative Example 1, separately, an SEM image of a cross section of the joint was acquired, an SEM / EDS image was acquired (element mapping), and a precise analysis was performed by EDS spectrum analysis. As a result, it was confirmed that there is a portion where the inorganic particles are hardly present (that is, the distribution of the inorganic particles is uneven) in the portion corresponding to about 5 area% of the entire immersed portion of the inorganic particle dispersion liquid.
From the fact that the distribution of the inorganic particles is uneven despite the same conditions as in Example 1 except for the presence or absence of the fluorescent substance, it can be considered that the fluorescent substance has a function of improving the dispersibility of the inorganic particles.

103 Metal member 104 Fine uneven shape 105 Resin member 106 Metal resin composite structure 107 Inorganic particle layer 110 Surface

Claims (6)

A method for manufacturing a metal-resin composite structure including a resin member and a metal member to be joined to the resin member.
A roughening step of forming a roughened surface on the surface of the metal member at least on a surface to be joined with the resin member.
A base treatment step of contacting an inorganic particle dispersion liquid containing an inorganic particle and a fluorescent substance on the roughened surface to provide an inorganic particle layer.
Includes an injection molding step of arranging the metal member after the base treatment step in an injection molding die and injecting a molten thermoplastic resin to form a resin member joined to the metal member. A method for manufacturing a metal-resin composite structure. The method for producing a metal-resin composite structure according to claim 1.
A method for producing a metal resin composite structure, wherein a fine concavo-convex structure is formed on the roughened surface, and the average value of the height difference between the concave portion and the convex portion is 10 nm to 200 μm. The method for producing a metal-resin composite structure according to claim 1 or 2.
The thermoplastic resin is a method for producing a metal resin composite structure containing an amorphous thermoplastic resin. The method for producing a metal-resin composite structure according to any one of claims 1 to 3.
The metal member is a method for producing a metal-resin composite structure containing one or more kinds of metals selected from the group consisting of iron-based metals, aluminum-based metals, magnesium-based metals, copper-based metals and titanium-based metals. The method for producing a metal-resin composite structure according to any one of claims 1 to 4.
A method for producing a metal resin composite structure in which the value of the mass of the inorganic particles / the mass of the fluorescent substance in the inorganic particle dispersion is in the range of 1 to 1000. A metal-resin composite structure including a resin member and a metal member to be joined to the resin member.
At least the surface of the metal member that is joined to the resin member is a roughened surface.
A metal-resin composite structure in which an inorganic particle layer containing inorganic particles and a fluorescent substance is provided between the metal member and the resin member.

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