CN105522782A - Metal base subjected to surface treatment, metal-resin compound, preparation methods and uses of metal-resin compound and metal base subjected to surface treatment, electronic product housing and preparation method of electronic product housing - Google Patents

Abstract

The invention discloses a surface-treated metal substrate and a preparation method thereof. The metal is aluminum or an aluminum alloy. The metal substrate includes a metal substrate and a hard anodized film attached to at least part of the surface of the metal substrate. layer, and first corrosion holes are distributed on the surface of the hard anodized film layer. The present invention also provides a metal-resin composite body, the metal is aluminum or aluminum alloy, the composite body includes a metal substrate and a resin layer, the metal substrate is the surface-treated metal substrate provided by the present invention, and the resin A layer is attached to at least part of the surface of the metal substrate, and part of the resin in the resin layer extends downward and fills the corrosion holes of the metal substrate. The metal-resin composite of the present invention has high bonding strength between the resin and the metal substrate, the resin layer is not easy to fall off from the surface of the metal substrate, has high structural stability, and can meet the requirements for high structural stability. The requirements of the occasion, suitable for electronic product casing.

Description

Surface-treated metal base material and metal-resin composite body, preparation method and application thereof, electronic product housing and preparation method

technical field

The present invention relates to a surface-treated metal substrate and its preparation method and application. The present invention also relates to a metal-resin composite and its preparation method and application. The present invention further relates to an electronic product shell and its preparation method .

Background technique

In the field of parts manufacturing for automobiles, home appliances, industrial machines, etc., aluminum or aluminum alloy and resin integrated molding technology is required.

At present, the commonly used method of combining aluminum or aluminum alloy and resin is gluing technology. This method combines aluminum or aluminum alloys with formed resins through chemical adhesives to obtain composites. However, in the composite body obtained by this method, the binding force between aluminum or aluminum alloy and resin is poor, and the adhesive bonding layer is not resistant to acid and alkali, which affects the use of the composite body. In addition, since the adhesive bonding layer has a certain thickness, it will affect the size of the final product.

In response to the above shortcomings of the adhesive method, researchers have developed other methods for combining aluminum or aluminum alloys with resins.

One method is to use amine substances, such as carbamate, hydrazine monohydrate, ethylenediamine, etc., to corrode the surface of aluminum or aluminum alloys to form nanoscale micropores on the surface of aluminum or aluminum alloys, and Keep the amine substances in the formed micropores, then inject the resin on the treated surface, and combine the resin with aluminum or aluminum alloy through the reaction between the amine substances and the resin, so as to obtain a certain tensile strength. Shear strength aluminum-plastic integrated product. However, if the aluminum or aluminum alloy is etched with the above-mentioned amine substances, the holes formed on the surface of the aluminum or aluminum alloy are too small, and it is difficult for the resin to be directly injected into the nano-scale micropores, so that it is difficult to significantly improve the bonding strength of the aluminum alloy and the resin. .

Another method is to directly corrode the surface of the aluminum alloy with an acid etching solution containing an inorganic halogen compound, and then inject resin to obtain an aluminum-plastic integrated product. However, in the aluminum-plastic integrated product obtained by this method, the bonding strength between the aluminum alloy and the resin still needs to be further improved.

In addition, it is also possible to perform anodic oxidation on the surface of the aluminum alloy to form a porous aluminum oxide film layer on the surface of the aluminum alloy, and then inject resin on the surface with the aluminum oxide film layer to obtain an aluminum-plastic integrated product. However, in the aluminum-plastic integrated product obtained by this method, the bonding strength between the aluminum alloy and the resin is not high.

Contents of the invention

The purpose of the present invention is to overcome the technical problem that the bonding strength between the metal substrate and the resin layer is not high in the existing metal-resin composite.

According to the first aspect of the present invention, the present invention provides a surface-treated metal substrate, the metal is aluminum or an aluminum alloy, the metal substrate includes a metal base and is formed on at least part of the surface of the metal base A hard anodized film layer, the surface of the hard anodized film layer is distributed with first corrosion holes.

According to a second aspect of the present invention, the present invention provides a method for surface treatment of a metal substrate, the metal being aluminum or an aluminum alloy, the method comprising providing a metal substrate, the metal substrate comprising a metal base and forming A hard anodized film layer on at least part of the surface of the metal substrate; performing a first etching on the metal substrate to form a first corrosion hole in the hard anodized film layer.

According to a third aspect of the invention, the invention provides a surface-treated metal substrate prepared by a method according to the second aspect of the invention.

According to a fourth aspect of the present invention, the present invention provides a metal-resin composite body, the metal is aluminum or aluminum alloy, the composite body includes a metal substrate and a resin layer, the metal substrate is provided by the present invention A surface-treated metal substrate, the resin layer is attached to at least part of the surface of the metal substrate, and part of the resin in the resin layer extends downward and fills the first corrosion hole or the second corrosion hole of the metal substrate. In the first corrosion hole and the second corrosion hole.

According to a fifth aspect of the present invention, the present invention provides a method for preparing a metal-resin composite, the metal is aluminum or an aluminum alloy, and the metal-resin composite includes a metal substrate and a A resin layer on at least part of the surface of the substrate, the metal substrate is the surface-treated metal substrate provided by the present invention, the method includes injecting a resin-containing composition into at least part of the surface of the metal substrate and making part of the composition It is filled in the first corrosion hole or the first corrosion hole and the second corrosion hole of the metal substrate, and forms a resin layer after molding.

According to a sixth aspect of the present invention, the present invention provides a metal-resin composite prepared by the method according to the fifth aspect of the present invention.

According to the seventh aspect of the present invention, the present invention provides the application of the metal-resin composite according to the present invention in the preparation of electronic product housings.

According to an eighth aspect of the present invention, the present invention provides an electronic product casing, which includes a metal casing body and at least one resin member attached to at least part of the inner surface and/or at least part of the outer surface of the metal casing body , wherein the metal shell body is the metal substrate according to the present invention.

According to a ninth aspect of the present invention, the present invention provides a method for manufacturing an electronic product housing, the method comprising forming at least one resin part on at least part of the inner surface and/or at least part of the outer surface of the metal shell body, wherein, using The resin member is formed according to the method for producing a metal-resin composite body of the present invention.

According to the metal-resin composite of the present invention, the bonding strength between the resin and the metal substrate is high, and the resin layer is not easy to fall off from the surface of the metal substrate, so the metal-resin composite provided by the present invention has higher structural stability, It can meet the requirements of occasions that require high structural stability, for example, it can be used as the casing of various electronic products.

Description of drawings

1 is a sectional view schematically illustrating a mobile phone casing according to the present invention, including a front view and a top view;

FIG. 2 is a cross-sectional view schematically illustrating a smart watch case according to the present invention.

Explanation of reference signs

1: Metal shell body of mobile phone 2: Resin layer

3: Opening 4: Smart watch metal case body

5: Resin lining layer 6: Signal element opening

detailed description

Herein, the metal may be pure aluminum or aluminum alloy. The aluminum alloy refers to an alloy formed by adding other elements to aluminum as a basic element, and may be various common aluminum alloys. Metal substrates are various molded bodies formed of aluminum or aluminum alloys, and can have various shapes according to specific use requirements.

According to a first aspect of the present invention, the present invention provides a surface-treated metal substrate, the metal is aluminum or an aluminum alloy, the metal substrate includes a metal base and at least part of the surface formed on the metal base The hard anodized film layer on the hard anodized film layer has first corrosion holes distributed on the surface of the hard anodized film layer.

When the surface-treated metal substrate is used in combination with a resin to make a metal-resin composite, the first etch holes can be used to accommodate the resin, thereby anchoring the resin to the surface of the metal substrate. The bonding strength between the resin and the metal substrate can be improved by selecting the size of the first corrosion hole.

The diameter of the first corrosion hole is preferably in the range of 10-200nm. When the pore diameter of the first corrosion hole is within the above range, on the one hand, it will not adversely affect the strength of the hard anodized film layer itself; on the other hand, it can also The resin layer is firmly anchored in the metal substrate, so that the resin layer and the metal substrate have high bonding strength, so that the metal-resin composite has high structural stability. From the perspective of further improving the bonding strength between the metal substrate and the resin layer in the metal-resin composite prepared by integral molding of the surface-treated metal substrate and resin, the aperture of the first corrosion hole Preferably in the range of 50-200 nm, more preferably in the range of 80-200 nm, still more preferably in the range of 100-200 nm. Herein, the term "within the range of" used to describe a numerical range includes both end values.

The ratio of the depth of the first corrosion hole to the thickness of the hard anodized film layer is preferably in the range of 0.1-1:1, more preferably in the range of 0.2-1:1, further preferably in the range of 0.5-1 : within the range of 1. Further preferably, the ratio of the depth of at least part of the first corrosion hole to the thickness of the hard anodized film layer is 1:1, such as preferably at least 50%, more preferably at least 60%, further preferably at least 70% of the first The ratio of the depth of the corrosion hole to the thickness of the hard anodized film layer is 1:1.

Herein, the diameter of a corrosion hole refers to the maximum size of the upper port of the corrosion hole (ie, the port on the surface) in the radial direction, and the depth of a corrosion hole refers to the vertical distance between two ends of a corrosion hole. The diameter and depth of corrosion holes can be measured by electron microscopy.

According to the surface-treated metal substrate of the present invention, there may be no corrosion holes on the surface of the metal substrate.

In a preferred embodiment, the metal base includes a base layer and a corrosion layer, the base layer and the corrosion layer are integrally structured, the corrosion layer is in contact with the hard anodized film layer and is In an integral structure, second corrosion holes are distributed on the surface of the corrosion layer, and the ratio of the depth of at least part of the first corrosion holes to the thickness of the hard anodized film layer is 1:1. When the metal base includes the base layer and the corrosion layer, the bonding between the metal base and the resin layer in the metal-resin composite obtained by integral molding of the metal base and the resin can be significantly improved strength.

In this paper, for the purpose of clarity, the corrosion holes distributed on the surface of the hard anodized film layer are referred to as "first corrosion holes", and the corrosion holes distributed on the surface of the metal substrate in contact with the hard anodized film layer are referred to as "first corrosion holes". It is called "second corrosion hole".

In this preferred embodiment, the base layer is a dense layer. That is, there are no corrosion holes in the base layer.

In this preferred embodiment, the pore diameter of the second corrosion hole is preferably in the range of 200-2000nm, more preferably in the range of 400-2000nm, further preferably in the range of 800-1500nm, such as in the range of 1000-1500nm In the range. The depth of the second corrosion hole is in the range of 0.1-500 μm, preferably in the range of 10-400 μm, more preferably in the range of 50-200 μm.

In this preferred embodiment, the ratio of the depth of at least part of the first corrosion hole to the thickness of the hard anodized film layer is 1:1, preferably at least 50%, more preferably at least 60%, further preferably at least 70%. The ratio of the depth of the first corrosion hole to the thickness of the hard anodized film layer is 1:1. In this preferred embodiment, the diameter of the first corrosion hole is as mentioned above, and will not be described in detail here.

According to the surface-treated metal substrate of the present invention, the hard anodized film layer has relatively high hardness, and its microhardness is generally 2000-2500HV, and the metal substrate is used to combine with resin to prepare metal-resin Compared with the anodized film layer on the surface of the metal substrate, the composite can fix the resin in the metal substrate more firmly, thereby obtaining higher bonding strength. The present invention has no special limitation on the thickness of the hard anodized film layer. Generally, the thickness of the hard anodized film layer can be in the range of 0.1-500 μm, preferably in the range of 1-200 μm, more preferably in the range of 5-100 μm, and more preferably in the range of 10-50 μm . The hard anodized film layer has not been sealed.

According to a second aspect of the present invention, the present invention provides a method for surface treatment of a metal substrate, the metal being aluminum or an aluminum alloy, the method comprising providing a metal substrate, the metal substrate comprising a metal base and forming A hard anodized film layer on at least part of the surface of the metal base. Herein, "at least in part" means part or all.

Various common methods can be used to perform hard anodic oxidation on the metal substrate to obtain a metal substrate with a hard oxide film layer on the surface. Specifically, under hard anodizing conditions, the metal substrate can be placed in the electrolyte, the metal substrate is used as the anode, and the conductive material that does not react with the electrolyte is used as the cathode, and the cathode and the anode are respectively connected to the power supply. The positive and negative electrodes are electrically connected, and electrolysis is carried out after electrification, thereby forming a hard anodic oxide film on the metal base. The electrolyte in the electrolytic solution may be one or more selected from sulfuric acid, oxalic acid, formic acid and citric acid.

The conditions of the hard anodic oxidation can be selected according to the expected thickness of the hard anodic oxidation film layer. Preferably, the conditions of the hard anodic oxidation are such that the thickness of the formed hard anodized film layer is 0.1-500 μm, preferably 1-200 μm, more preferably 10-100 μm, further preferably 15-50 μm. Specifically, the voltage can be 10-100V, preferably 40-80V; the temperature of the electrolyte can be 0-60°C, preferably 0-10°C. The time of electrolysis can be selected according to specific electrolysis conditions, so that the thickness of the formed hard anodized film layer can meet the requirements. Generally, the time of electrolysis can be 1-60 minutes, preferably 10-30 minutes. minute.

The metal substrate is preferably pre-treated by various methods commonly used in the art before hard anodizing. Generally, the pretreatment includes mechanical grinding or grinding to remove obvious foreign matter on the surface of the metal substrate, and then degreasing and cleaning the metal substrate in order to remove grease on the surface of the metal substrate.

According to the method of the present invention, further comprising performing a first etching on the metal substrate to form a first corrosion hole in the hard anodized film layer.

The condition of the first etching is such that the diameter of the first etching hole is preferably in the range of 10-200nm, more preferably in the range of 50-200nm, further preferably in the range of 80-200nm, most preferably in the range of 100-200nm. In the range of 200nm; The ratio of the depth of the first corrosion hole to the thickness of the hard anodized film layer is preferably in the range of 0.1-1:1, more preferably in the range of 0.2-1:1, further Preferably in the range of 0.5-1:1, and the ratio of the depth of at least part of the first corrosion hole to the thickness of the hard anodized film layer is 1:1, such as preferably more than 50%, more preferably more than 60%, Further preferably, the ratio of at least 70% or more of the depth of the first corrosion hole to the thickness of the hard anodized film layer is 1:1.

Various conventional methods can be used to perform the first etching on the metal substrate, so as to form the first corrosion holes in the hard anodized film layer.

In one embodiment, the first etching includes: immersing the metal substrate in an alkaline etching solution, so as to form a first corrosion hole in the hard anodized film layer.

The alkaline etchant may be a common etchant capable of corroding a hard anodized film layer. Preferably, the etching solution is one or a combination of the following two etching solutions. A better etching effect can be obtained by using one or a combination of the following two etching solutions to etch the metal substrate. These two etching solutions will be described separately below.

1. The alkaline etching solution contains one or more of the hydrazine derivatives selected from water-soluble hydroxides, water-soluble alkaline salts, ammonia, water-soluble amines, hydrazine, and one or more hydrogen atoms replaced by hydrocarbon groups. An aqueous solution of two or more substances.

The water-soluble hydroxide may be an alkali metal hydroxide, preferably sodium hydroxide and/or potassium hydroxide, more preferably sodium hydroxide.

The water-soluble basic salt refers to a water-soluble basic salt whose aqueous solution has a pH value greater than 7. Specifically, the water-soluble alkaline salt can be water-soluble carbonate, water-soluble bicarbonate, water-soluble phosphate, water-soluble monohydrogen phosphate, water-soluble dihydrogen phosphate and water-soluble borate One or more than two. The water-soluble basic salt may be an alkali metal salt, preferably a sodium salt or a potassium salt, more preferably a sodium salt. Preferably, the water-soluble basic salt is one or more of Na ₂ CO ₃ , NaHCO ₃ , NaH ₂ PO ₄ , Na ₂ HPO ₄ , Na ₃ PO ₄ and Na ₂ B ₄ O ₇ .

The water-soluble amine may be various common amines that can be dissolved in water. Preferably, the water-soluble amine is one or more of ethylenediamine, diethylamine, ethanolamine, trimethylamine, methylamine and dimethylamine.

The hydrazine derivative refers to a compound formed by replacing one or more hydrogen atoms in the molecular structure of hydrazine (ie, H ₂ N-NH ₂ ) with a hydrocarbon group, and the hydrocarbon group is preferably a C ₁ -C ₄ alkyl group, specifically It can be monomethylhydrazine and/or 1,1-dimethylhydrazine.

The alkaline etching solution is preferably an aqueous solution containing a water-soluble hydroxide and/or a water-soluble alkaline salt. More preferably, the alkaline etching solution is an aqueous solution containing a water-soluble alkaline salt, and the water-soluble alkaline salt is preferably Na ₂ CO ₃ and/or NaHCO ₃ , more preferably Na ₂ CO ₃ or NaHCO ₃ .

The pH value of the alkaline etching solution is preferably in the range of 10-13, so that not only a suitable etching rate can be obtained, but also the etching process is mild and easy to control.

2. The alkaline etching solution is an alkaline buffer solution, so that the distribution of the finally formed corrosion pores is more uniform and the size of the pores is more concentrated.

The alkaline etching solution may be an aqueous solution containing water-soluble hydroxides and water-soluble alkaline salts. The cations of the water-soluble hydroxide and the water-soluble basic salt may be the same or different, but are preferably the same.

The water-soluble hydroxide may be an alkali metal hydroxide, preferably sodium hydroxide and/or potassium hydroxide, more preferably sodium hydroxide.

Described water-soluble alkaline salt can be one or in water-soluble carbonate, water-soluble bicarbonate, water-soluble phosphate, water-soluble monohydrogen phosphate, water-soluble dihydrogen phosphate and water-soluble borate Two or more. The water-soluble basic salt may be an alkali metal salt, preferably a sodium salt or a potassium salt, more preferably a sodium salt. Preferably, the water-soluble basic salt is one or more of Na ₂ CO ₃ , NaHCO ₃ , NaH ₂ PO ₄ , Na ₂ HPO ₄ , Na ₃ PO ₄ and Na ₂ B ₄ O ₇ . Preferably, the water-soluble alkaline salt is water-soluble monohydrogen phosphate and/or water-soluble dihydrogen phosphate. More preferably, the water-soluble alkaline salt is a water-soluble dihydrogen phosphate salt, such as one or more of sodium dihydrogen phosphate, potassium dihydrogen phosphate, ammonium dihydrogen phosphate and aluminum dihydrogen phosphate.

The alkaline etching solution may also be an aqueous solution containing a water-soluble normal salt and a water-soluble acid salt. The normal salt refers to a salt in which the cation only contains metal ions and/or ammonium ions, and the acidic salt refers to a salt in which the cations also contain hydrogen ions in addition to metal ions and/or ammonium ions. The cation and acid ion of the water-soluble normal salt and the water-soluble acid salt may be the same or different, but are preferably the same.

The alkaline etching solution is preferably an aqueous solution containing water-soluble carbonate and water-soluble bicarbonate, or an aqueous solution containing water-soluble phosphate and water-soluble monohydrogen phosphate. Specifically, the alkaline etching solution may be an aqueous solution containing Na ₂ CO ₃ and NaHCO ₃ , or an aqueous solution containing Na ₃ PO ₄ and Na ₂ HPO ₄ .

The alkaline etching solution can also be an aqueous solution containing ammonia and water-soluble ammonium salts. The water-soluble ammonium salt is preferably one or more of NH ₄ Cl, (NH ₄ ) ₂ SO ₄ , NH ₄ HCO ₃ and NH ₄ NO ₃ . Specifically, the alkaline etching solution may be an aqueous solution containing NH ₃ and NH ₄ Cl, an aqueous solution containing NH ₃ and (NH ₄ ) ₂ SO ₄ , an aqueous solution containing NH ₃ and NH ₄ HCO ₃ or an aqueous solution containing NH ₃ and Aqueous solution of NH ₄ NO ₃ .

The alkaline etching solution is preferably an aqueous solution containing a water-soluble hydroxide and a water-soluble alkaline salt, or an aqueous solution containing a water-soluble normal salt and a water-soluble acid salt, more preferably containing a water-soluble normal salt and a water-soluble Aqueous solution of acid salt.

The alkaline etching solution is preferably an alkaline buffer solution with a pH value of 10-13, so that a suitable etching rate can be obtained, and the etching process is mild and easy to control.

In the first etching, the temperature of the alkaline etching solution may be 10-60° C., preferably 20-40° C.; the time of the first etching may be 1-60 minutes, preferably 5-20 minutes.

The metal substrate with the first corrosion holes formed in the hard anodized film layer after the first etching can be directly used as the surface-treated metal substrate and integrally molded with the resin to prepare a metal-resin composite.

In a more preferred embodiment, the first etched metal substrate is subjected to second etching to form second corrosion holes on the surface of the metal substrate in contact with the hard anodized film layer. When the surface-treated metal substrate obtained by the second etching is used to combine with resin to prepare a metal-resin composite, the resin layer and the metal substrate exhibit higher bonding strength.

The conditions of the second etching are preferably such that the diameter of the second etching hole is preferably in the range of 200-2000nm, more preferably in the range of 400-2000nm, further preferably in the range of 800-1500nm, such as in the range of 1000-2000nm. 1500nm range. From the perspective of further improving the bonding strength between the metal substrate and the resin layer in the metal-resin composite formed after the integral molding of the surface-treated metal substrate and resin, the conditions of the second etching are such that The depth of the second corrosion hole is in the range of 0.1-500 μm, preferably in the range of 10-400 μm, more preferably in the range of 50-200 μm.

Various methods may be used to form the second etch holes. In a preferred implementation manner, the second etching includes: immersing the first etched metal substrate in an acidic etching solution.

The acidic etching solution is an aqueous solution containing acid, and the acid is hydrohalic acid and/or H ₃ PO ₄ , preferably HCl or H ₃ PO ₄ .

Preferably, the acidic etching solution also contains one or more than two kinds of water-soluble salts, which can further improve the stability of etching. The acid group of the water-soluble salt is preferably the same as that of the acid contained in the acidic etching solution. For example, when the acidic etching solution is an aqueous solution containing hydrohalic acid, the acidic etching solution preferably also contains one or more water-soluble hydrohalide salts; when the acidic etching solution is an aqueous solution containing phosphoric acid, The acidic etchant preferably also contains one or more water-soluble phosphates. Specifically, when the acidic etching solution is hydrochloric acid, the water-soluble salt is preferably one or more of NaCl, KCl and AlCl ₃ . When the acidic etching solution is phosphoric acid, the water-soluble salt is one or more of water-soluble phosphate, water-soluble monohydrogen phosphate and water-soluble dihydrogen phosphate, such as NaH ₂ PO ₄ , Na ₂ One or more of HPO ₄ , Na ₃ PO ₄ , KH ₂ PO ₄ , K ₂ HPO ₄ and K ₃ PO ₄ .

The content of the water-soluble salt in the acidic etching solution depends on the amount of acid in the acidic etching solution. Generally, the molar ratio of the water-soluble salt to the acid may be 0.1-1:1, preferably 0.2-0.8:1, more preferably 0.4-0.6:1.

The pH value of the acidic etching solution is preferably 1-3, so that the distribution of corrosion holes in the surface-treated metal substrate formed in this way is more uniform, and the pore size distribution is also more concentrated, and the metal-resin prepared by the metal substrate The bond strength of the resin to the metal substrate in the composite is higher.

Specifically, the temperature of the acidic etching solution may be 20-30° C., and the immersion time of the metal substrate in the acidic etching solution may be 1-60 minutes, preferably 10-30 minutes.

According to the method of the present invention, in a preferred example, in the first etching, the metal substrate is soaked in an alkaline etching solution; in the second etching, the first etched metal The substrate is soaked in an acid etchant. Etching in this way, the etching heat release is small during the etching process, the etching process is mild and easy to control, the distribution of the formed first corrosion hole and the second corrosion hole is more uniform, and the hole size (including hole diameter and depth) is more concentrated and, when the surface-treated metal substrate obtained by the method is used in combination with resin to prepare a metal-resin composite, the resin layer and the metal substrate exhibit higher bonding strength.

According to the method of the present invention, each of the first etching and the second etching can be performed only once, or in multiples, and the duration of each etching is not particularly limited, as long as the total etching time meets the above requirements. Wash with water between two etchings to remove the residual etching solution from the previous etching.

According to a third aspect of the invention, the invention provides a surface-treated metal substrate prepared by a method according to the second aspect of the invention.

According to a fourth aspect of the present invention, the present invention provides a metal-resin composite body, the metal is aluminum or aluminum alloy, the composite body includes a metal substrate and a resin layer, the metal substrate is provided by the present invention A surface-treated metal substrate, the resin layer is attached to at least part of the surface of the metal substrate, and part of the resin in the resin layer extends downward and fills the first corrosion hole or the second corrosion hole of the metal substrate. In the first corrosion hole and the second corrosion hole.

The surface-treated metal substrate and its preparation method have been described in detail above, and will not be described in detail here.

According to the composite body of the present invention, the thickness of the resin layer can be selected according to specific usage occasions. Generally, the thickness of the resin layer may be in the range of 0.1-10 mm, preferably in the range of 0.5-5 mm. Herein, the thickness of the resin layer refers to the vertical distance from the upper surface of the hard anodized film layer to the upper surface of the resin layer.

The main resin in the resin layer can be selected according to specific usage requirements, as long as the resin can be combined with aluminum or aluminum alloy. Generally, the main resin in the resin layer can be selected from thermoplastic resins, such as one or more of polyphenylene sulfide, polyester, polyamide, polycarbonate and polyolefin. The polyester can be a common polymer formed by condensation of dicarboxylic acid and diol, and its specific examples can include but not limited to polybutylene terephthalate and/or polyethylene terephthalate ester. The polyamide can be a common polymer formed by the condensation of diamine and dicarboxylic acid, and its specific examples can include but not limited to polyhexamethylene adipamide, polyhexamethylene adipamide, polysuccinyl Hexamethylenediamine, polyhexamethylene dodecane diamide, polyhexamethylene sebacamide, polydecanediamide sebacamide, polyundecamide, polydodecylamide, polyoctylamide, poly-9-aminononanoic acid , polycaprolactam, polyphenylene terephthalamide, polyhexamethylene isophthalamide, polyhexamethylene terephthalamide and polynonanediamide terephthalamide. Specific examples of the polyolefin may include, but are not limited to, polystyrene, polypropylene, polymethylmethacrylate, and poly(acrylonitrile-butadiene-styrene).

The resin layer may contain at least one filler in addition to the main resin. The type of the filler can be selected according to specific usage requirements. The filler may be a fiber filler and/or a powder filler. The fibrous filler may be one or more selected from glass fiber, carbon fiber and aramid fiber. The powder type filler may be one or more selected from calcium carbonate, magnesium carbonate, silicon dioxide, heavy barium sulfate, talcum powder, glass and clay. The content of the filler can be conventionally selected. Generally, preferably, based on 100 parts by weight of the main resin, the content of the filler may be 20-150 parts by weight, preferably 25-100 parts by weight, more preferably 30-50 parts by weight.

According to a fifth aspect of the present invention, the present invention provides a method for preparing a metal-resin composite, the metal is aluminum or an aluminum alloy, and the metal-resin composite includes a metal substrate and a A resin layer on at least part of the surface of the substrate, the metal substrate is the surface-treated metal substrate provided by the present invention, the method includes injecting a resin-containing composition into at least part of the surface of the metal substrate and making part of the composition It is filled in the first corrosion hole or the first corrosion hole and the second corrosion hole of the metal substrate, and forms a resin layer after molding.

The resin in the resin-containing composition (hereinafter referred to as the host resin) is the same as the host resin in the above-mentioned resin layer, and will not be described in detail here. The resin-containing composition may contain, in addition to the host resin, at least one filler and/or at least one fluidity improver. The types of the fillers are the same as those in the aforementioned resin layer, and will not be described in detail here.

The content of the filler can be conventionally selected. Generally, based on 100 parts by weight of the main resin, the content of the filler may be 20-150 parts by weight, preferably 25-100 parts by weight, more preferably 30-50 parts by weight.

The fluidity improver is used to improve the fluidity of the main resin, further improve the bonding strength between the metal substrate and the resin and the processing performance of the resin. The fluidity improver can be various substances capable of achieving the above effects, preferably a cyclic polyester.

The amount of the fluidity improver is subject to improving the fluidity of the main resin. Preferably, relative to 100 parts by weight of the main resin, the content of the fluidity improver is 1-5 parts by weight.

The resin-containing composition can also contain common various auxiliary agents according to specific usage requirements, such as colorants and/or antioxidants, to improve the performance of the resin layer in the metal-resin composite that is finally formed or to give the Resin layer with new performance.

The resin-containing composition can be obtained by uniformly mixing a host resin, an optional filler, an optional fluidity improver, and an optional auxiliary. Generally, it can be obtained by uniformly mixing the main resin, optional fillers, optional fluidity improvers and optional auxiliary agents, and performing extrusion granulation.

The resin-containing composition can be injected into the etched surface of the metal substrate by various methods commonly used. In a preferred embodiment of the present invention, the metal substrate is placed in a mold, and the resin-containing composition is injected by injection molding.

The injection molding conditions can be selected according to the type of main resin in the resin-containing composition. Preferably, the injection molding conditions include: the mold temperature is 50-300°C, the nozzle temperature is 200-450°C, the holding time is 1-50 seconds, the injection pressure is 50-300MPa, and the injection time is 1-30 seconds, The delay time is 1-30 seconds.

The injection amount of the resin-containing composition can be selected according to the expected thickness of the resin layer. Generally, the injection amount of the resin-containing composition is such that the thickness of the formed resin layer may be 0.1-10 mm, preferably 0.5-5 mm.

According to the method of the present invention, when the resin layer is only formed on a part of the surface of the metal base material, the surface that does not need to be formed with the resin layer can be treated to remove surface holes and surface color changes caused by etching. This treatment can be performed during injection molding. It may be performed before the step or after the injection molding step, and is not particularly limited.

According to a sixth aspect of the present invention, the present invention also provides a metal-resin composite prepared by the method according to the fifth aspect of the present invention.

According to the seventh aspect of the present invention, the present invention provides the application of the metal-resin composite according to the present invention in the preparation of electronic product housings.

According to an eighth aspect of the present invention, the present invention provides an electronic product casing, which includes a metal casing body and at least one resin member attached to at least part of the inner surface and/or at least part of the outer surface of the metal casing body , wherein the metal shell body is the metal substrate according to the present invention. In the present invention, the casing not only includes a sheet-shaped casing, but also includes various frame structures, such as an outer frame.

According to the housing of the electronic product of the present invention, according to specific requirements, at least one opening may be provided on the metal housing body, so as to install components of the electronic product that need to avoid the metal housing body at a corresponding position of the opening. In one embodiment, since metal has a shielding effect on electromagnetic signals, the position of at least part of the opening may correspond to the installation position of the signal emitting element and/or the signal receiving element. At this time, the opening position is preferably provided with a resin part, and Part of the resin in the resin part is filled in the opening, and the signal transmitting element and/or the signal receiving element can be installed on the resin part.

According to the housing of the electronic product of the present invention, the metal housing body may be of an integral structure or of a spliced structure. The splicing structure means that the metal shell body includes at least two parts disconnected from each other, and the two parts are spliced together to form the metal shell body.

When the metal shell body is a joint structure, two adjacent parts can be bonded together with an adhesive. In a preferred embodiment, the resin part is provided at the splicing position of two adjacent parts, and the resin part overlaps with the two adjacent parts respectively and covers the splicing position (that is, the resin part bridges the two adjacent parts. part), which can improve the bonding strength of the splicing position; and, according to the internal structure of the electronic product, the metal shell body can be divided into multiple parts, and the resin part can form the metal shell body into a whole. , It can also be used as a mounting base for some electronic components.

According to the electronic product casing of the present invention, at least part of the outer surface of the metal shell body can be attached with a resin part, and the resin part can cover the entire outer surface, or cover a part of the outer surface of the metal shell body to form a pattern, such as a decoration sexual pattern.

According to the electronic product case of the present invention, when the inner surface of the metal case body is attached with a resin part, the resin part can be arranged at one or more positions as required. In a preferred embodiment, the resin part is attached to the entire inner surface of the metal shell body, and at this time, the resin part is preferably a one-piece structure. According to this preferred embodiment, it is especially suitable for occasions where the metal shell body is a spliced structure.

The electronic product casing according to the present invention can be various electronic product casings that require metal as the casing, for example: the casing or frame of a mobile terminal, or the casing or frame of a wearable electronic device. The mobile terminal refers to a device that can be in a mobile state and has a wireless transmission function, such as a mobile phone, a portable computer (including a notebook computer and a tablet computer). The wearable electronic device refers to an intelligent wearable device, such as a smart watch and a smart bracelet. Specifically, the electronic product may be, but not limited to, one or more of mobile phones, portable computers (such as notebook computers and tablet computers), smart watches and smart bracelets.

Fig. 1 shows a front view and a top view of an embodiment when the housing of the electronic product is a mobile phone housing. As shown in FIG. 1 , a plurality of openings 3 are opened on the metal case body 1 of the mobile phone, and the positions of the openings 3 may correspond to the positions where antennas are installed and various buttons are installed. The resin layer 2 is attached to the entire inner surface of the metal case body 1 of the mobile phone. The resin layer 2 is integrally structured and part of the resin in the resin layer 2 is filled in the opening 3 .

Fig. 2 shows a front view of an embodiment in which the housing of the electronic product is a housing of a smart watch. As shown in 2, the metal shell body 4 of the smart watch is provided with a signal element opening 6 corresponding to the installation of the signal transmitting element and/or signal receiving element, the inner surface of the metal shell body 4 of the smart watch is attached with a resin lining layer 5, and the resin Part of the resin in the inner lining layer 5 is filled in the opening 6 of the signal element, and the signal element can be installed at a corresponding position on the resin inner lining layer 5 .

According to a ninth aspect of the present invention, the present invention provides a method for manufacturing an electronic product housing, the method comprising forming at least one resin part on at least part of the inner surface and/or at least part of the outer surface of the metal shell body, wherein, using The resin member is formed according to the method for producing a metal-resin composite body of the present invention.

The present invention will be described in detail below in conjunction with the examples, but the scope of the present invention is not limited thereto.

In the following examples and comparative examples, with reference to the method specified in ASTM D1002-10, the average shear strength between the metal matrix and the resin layer in the metal-resin composite was measured on an INSTRON3369 universal testing machine.

In the following examples and comparative examples, the thickness of the anodized film layer and the depth of the corrosion hole are measured by the metallographic microscope of the model AxioImagerAlm purchased from ZEISS (observing five different positions of the same sample, measuring the appearance in the field of view) Depth of all corrosion holes), using a scanning electron microscope purchased from Japan Electronics Co., Ltd. to measure the diameter of the corrosion holes (five different positions of the same sample are observed, and all corrosion holes appearing in the measurement field of view are measured). aperture).

In the following examples and comparative examples, the microhardness of the hard anodized film layer was measured using a model HX-1000TM/LCD microhardness tester purchased from Shanghai No. 1 Optical Instrument Factory.

Examples 1-12 serve to illustrate the invention.

Example 1

(1) A commercially available 5052 aluminum alloy plate with a thickness of 1 mm was cut into rectangular pieces of 15 mm×80 mm. Put the rectangular piece into the polishing machine for polishing. Then, it was washed with absolute ethanol, then immersed in an aqueous solution of sodium hydroxide with a concentration of 2% by weight, taken out after 2 minutes, and rinsed with deionized water to obtain a pretreated aluminum alloy sheet.

(2) the aluminum alloy sheet that step (1) obtains is put into as anode and contains the aqueous solution of 1% by weight of NaOH and 0.1% by weight of sodium silicate as the hard anodic oxidation tank of electrolytic solution, with graphite carbon plate as cathode , at a voltage of 60V, electrolysis at 10°C for 15 minutes for hard anodizing. The hard anodized aluminum alloy sheet is taken out and dried to obtain an aluminum alloy sheet with a hard anodized film layer on the surface. The cross-section of the aluminum alloy sheet was observed with a microscope, and it was confirmed that the thickness of the hard anodized film layer was 25 μm, and the microhardness of the hard anodized film layer was 2200HV.

(3) Soak the aluminum alloy sheet with a hard anodized film layer on the surface obtained in step (2) in an aqueous solution (pH=11) containing Na ₂ HPO ₄ as an etching solution at a temperature of 20°C. After 15 minutes, the aluminum alloy sheet was taken out, soaked in water for 1 minute, and then taken out and dried to obtain an alkali-etched aluminum alloy sheet.

Adopt the cross-section of the aluminum alloy plate that microscope observation step (3) obtains, find: in the hard anodic oxidation film layer, be distributed with the corrosion hole in the scope of 50-200nm, the depth of this corrosion hole is the same as that of the hard anodic oxidation film layer The ratio of the thickness is in the range of 0.2-1:1, and the ratio of the depth of more than 60% of the corrosion holes to the thickness of the hard anodized film layer is 1:1.

(4) Place the aluminum alloy sheet that step (3) obtains in the injection molding mold, and inject a resin composition containing glass fiber and polyphenylene sulfide (PPS) on one surface of the aluminum alloy sheet (relative to 100 parts by weight of PPS , the content of glass fibers is 35 parts by weight), demoulding and cooling. Among them, the injection molding conditions include: the mold temperature is 120°C, the nozzle temperature is 305°C, the dwell time is 5 seconds, the injection pressure is 120MPa, the injection time is 5 seconds, and the delay time is 3 seconds.

Put the cooled product into a constant temperature drying oven at 120°C for 1.5 hours, and then cool it down to room temperature naturally with the furnace to obtain a metal-resin composite (the thickness of the resin layer is 5 mm), and its average shear strength is listed in Table 1. listed in .

Example 2

Use the same method as in Example 1 to carry out surface treatment on the aluminum alloy sheet and prepare a metal-resin composite body. The difference is that in step (2), the electrolyte used contains 1% by weight of NaOH and 0.1% by weight of phosphoric acid. Sodium aqueous solution, electrolysis time is 10 minutes.

Adopt the cross-section of the aluminum alloy plate that microscope observation step (3) obtains, find: in the hard anodized film layer, be distributed with the corroded hole in the scope of 10-200nm, the depth of this corroded hole is the same as the hard anodized film layer The ratio of the thickness is in the range of 0.1-1:1, and the ratio of the depth of more than 50% of the corrosion holes to the thickness of the hard anodized film layer is 1:1. The average shear strengths of the prepared metal-resin composites are listed in Table 1.

Example 3

The aluminum alloy sheet was surface treated and a metal-resin composite was prepared using the same method as in Example 1, except that in step (3), the etching solution was an aqueous solution of NaOH (pH=11).

Adopt the cross-section of the aluminum alloy plate that microscope observation step (3) obtains, find: in the hard anodized film layer, be distributed with the corroded hole in the scope of 10-200nm, the depth of this corroded hole is the same as the hard anodized film layer The ratio of the thickness is in the range of 0.1-1:1, and the ratio of the depth of more than 50% of the corrosion holes to the thickness of the hard anodized film layer is 1:1. The average shear strengths of the prepared metal-resin composites are listed in Table 1.

Comparative example 1

(1) A pretreated aluminum alloy sheet was prepared by the same method as in step (1) of Example 1.

(2) Using the same method as in step (4) of Example 1, the resin composition is injected on the surface of the aluminum alloy sheet obtained in step (1) of Comparative Example 1 to form a resin layer, thereby obtaining a metal-resin composite body, the average Shear strengths are listed in Table 1.

Comparative example 2

(1) A pretreated aluminum alloy sheet was prepared by the same method as in step (1) of Example 1.

(2) The aluminum alloy sheet obtained in the step (1) of the comparative example 2 was subjected to hard anodic oxidation by the same method as the step (2) of the embodiment 1.

(3) Using the same method as in step (4) of Example 1, the resin composition is injected on the surface of the aluminum alloy sheet obtained in step (2) of Comparative Example 2 to form a resin layer, thereby obtaining a metal-resin composite body, the average Shear strengths are listed in Table 1.

Comparative example 3

(1) A pretreated aluminum alloy sheet was prepared by the same method as in step (1) of Example 1.

(2) The aluminum alloy sheet obtained in step (1) is anodized by the following method to obtain anodized aluminum alloy sheet:

The aluminum alloy sheet that step (1) obtains is put into as anode with the concentration of 20% by weight H ₂ SO _The aqueous solution is used as the anode oxidation tank of electrolytic solution, with the graphite carbon plate as the negative electrode, under the voltage of 18V, at 20 ℃ electrolysis for 15 minutes. The anodized aluminum alloy sheet is taken out and dried to obtain an aluminum alloy sheet with an anodized film layer on the surface. The cross-section of the aluminum alloy sheet was observed with a microscope, and it was confirmed that the thickness of the anodized film layer was 25 μm, and the microhardness was 200 HV.

(3) Soak the aluminum alloy sheet with an anodized film layer on the surface obtained in step (2) in an aqueous solution (pH=11) containing Na ₂ HPO ₄ at a temperature of 20°C. After 15 minutes, the aluminum alloy sheet was taken out, soaked in water for 1 minute, and then taken out and dried to obtain an alkali-etched aluminum alloy sheet.

Adopt the cross-section of the aluminum alloy sheet that step (3) obtains under the microscope, find: in the anodic oxidation film layer, be distributed with the corrosion hole in the scope of 50-200nm, the ratio of the depth of this corrosion hole and the thickness of the anodic oxidation film layer In the range of 0.2-1:1, the ratio of the depth of the corrosion hole to the thickness of the hard oxide film layer is 1:1 in more than 60% of the corrosion holes.

(4) The metal-resin composite was prepared by the same method as step (4) of Example 1, and its average shear strength is listed in Table 1.

Example 4

Using the same method as in Example 1 to carry out surface treatment to the aluminum alloy sheet and prepare a metal-resin composite body, the difference is that step (3) is divided into step (3-1) and step (3-2), in step ( In 3-1), the same method as that of step (3) of Example 1 is used to etch the hard anodized aluminum alloy sheet, and in step (3-2) the acid etching solution is used to etch the aluminum alloy sheet through alkali etching Carry out etching, step (3-2) is specifically as follows:

The alkali-etched aluminum alloy sheet obtained in step (3-1) was immersed in hydrochloric acid (pH=2) as an etching solution at a temperature of 20°C. After 12 minutes, the aluminum alloy sheet was taken out, soaked in water for 1 minute, and then taken out and dried to obtain an acid-etched aluminum alloy sheet.

Adopt the cross-section of the aluminum alloy sheet that step (3-2) obtains by microscope observation, find: the hard anodized film layer is distributed with the first corroded hole with aperture in the scope of 50-200nm, and the depth of the first corroded hole and hard The ratio of the thickness of the hard anodized film layer is in the range of 0.2-1:1, and the ratio of the depth of the first corrosion hole to the thickness of the hard anodized film layer is 1:1 for more than 60% of the first corrosion holes; the aluminum alloy substrate is divided into A dense base layer and a corrosion layer with a second corrosion hole, the corrosion layer is in contact with the hard anodized film layer, the diameter of the second corrosion hole is in the range of 200-2000nm, and the depth of the second corrosion hole is in the range of 0.1-400μm within range. The average shear strengths of the prepared metal-resin composites are listed in Table 1.

Comparative example 4

Using the same method as in Example 4 to carry out surface treatment on the aluminum alloy sheet and prepare a metal-resin composite, the difference is that step (2) uses the same method as in step (2) of Comparative Example 3 to form an anode on the surface of the aluminum alloy sheet Oxide film layer;

In step (3-1), the aluminum alloy sheet with anodized film layer on the surface obtained in step (2) is soaked in an aqueous solution (pH=11) containing Na ₂ HPO ₄ at a temperature of 20°C. After 15 minutes, the aluminum alloy sheet is taken out, soaked in water for 1 minute, then taken out and dried to obtain an alkali-etched aluminum alloy sheet;

In step (3-2), the alkali-etched aluminum alloy sheet obtained in step (3-1) is soaked in hydrochloric acid (pH=2) at a temperature of 20°C. After 12 minutes, the aluminum alloy sheet was taken out, soaked in water for 1 minute, and then taken out and dried to obtain an acid-etched aluminum alloy sheet.

Adopt the cross-section of the aluminum alloy sheet that step (3-2) obtains by microscope observation, find that: the anodized film layer is distributed with the first corrosion hole in the scope of 50-200nm aperture, the depth of the first corrosion hole and anodic oxide film The ratio of layer thickness is in the range of 0.2-1:1, and the ratio of the depth of more than 60% of the first corrosion hole to the thickness of the anodized film layer is 1:1; the aluminum alloy matrix is divided into a dense matrix layer and a For the corrosion layer of the second corrosion hole, the corrosion layer is in contact with the anodized film layer, the diameter of the second corrosion hole is in the range of 200-2000 nm, and the depth of the second corrosion hole is in the range of 0.1-400 μm. The average shear strengths of the prepared metal-resin composites are listed in Table 1.

Comparative example 5

Using the same method as in Example 1 to carry out surface treatment to the aluminum alloy sheet and prepare a metal-resin composite body, the difference is that step (3) is divided into step (3-1) and step (3-2), in step ( In 3-1), the same method as step (3-2) in Example 4 is used to etch the aluminum alloy sheet through hard anodic oxidation, and in step (3-2), the same method as in Example 1 step (3 ) The same method is used to etch the acid-etched aluminum alloy sheet.

Adopt the cross-section of the aluminum alloy sheet that step (3-2) obtains by microscope observation, find: the hard anodized film layer is distributed with the first corroded hole with aperture in the scope of 50-200nm, and the depth of the first corroded hole and hard The ratio of the thickness of the hard anodized film layer is in the range of 0.2-1:1, and the ratio of the depth of the first corrosion hole to the thickness of the hard anodized film layer for more than 60% is 1:1; the aluminum alloy substrate is divided into A dense base layer and a corrosion layer with a second corrosion hole, the corrosion layer is in contact with the hard anodized film layer, the diameter of the second corrosion hole is in the range of 500-4500nm, and the depth of the second corrosion hole is in the range of 0.1-400μm within range. The average shear strengths of the prepared metal-resin composites are listed in Table 1.

Comparative example 6

Use the same method as in Example 1 to carry out surface treatment on the aluminum alloy sheet and prepare a metal-resin composite. Anodized aluminum alloy sheets are etched.

Adopt the cross-section of the aluminum alloy sheet that step (3) obtains under microscope, find: there is no corrosion hole substantially in the hard anodized film layer; The hard anodized film layers are connected, the diameter of the corrosion hole is in the range of 800-5000nm, and the depth of the corrosion hole is in the range of 0.01-500μm. The average shear strengths of the prepared metal-resin composites are listed in Table 1.

Example 5

Use the same method as in Example 4 to carry out surface treatment on the aluminum alloy sheet and prepare a metal-resin composite body. The difference is that in step (3-2), the etching solution is hydrochloric acid (pH=2) containing NaCl, and NaCl and The molar ratio of HCl is 0.5:1.

Adopt the cross-section of the aluminum alloy sheet that step (3-2) obtains by microscope observation, find: the hard anodized film layer is distributed with the first corroded hole with aperture in the scope of 50-200nm, and the depth of the first corroded hole and hard The ratio of the thickness of the hard anodized film layer is in the range of 0.2-1:1, and the ratio of the depth of the first corrosion hole to the thickness of the hard anodized film layer for more than 60% is 1:1; the aluminum alloy substrate is divided into A dense base layer and a corrosion layer with a second corrosion hole, the corrosion layer is in contact with the hard anodized film layer, the diameter of the second corrosion hole is in the range of 500-2000nm, and the depth of the second corrosion hole is in the range of 50-200μm within range. The average shear strengths of the prepared metal-resin composites are listed in Table 1.

Example 6

Using the same method as in Example 4 to carry out surface treatment on the aluminum alloy sheet and prepare a metal-resin composite body, the difference is that in step (3-1), the etching solution is an aqueous solution containing Na ₃ PO ₄ and Na ₂ HPO ₄ (pH=11).

The cross-section of the aluminum alloy sheet obtained by the microscope observation step (3-2) is found to be: the hard anodized film layer is distributed with first corrosion holes with a pore diameter in the range of 100-200nm, and the depth of the first corrosion holes is related to the hard anodic oxidation film layer. The ratio of the thickness of the hard anodized film layer is in the range of 0.5-1:1, and the ratio of the depth of the first corrosion hole to the thickness of the hard anodized film layer for more than 70% is 1:1; the aluminum alloy substrate is divided into A dense base layer and a corrosion layer with a second corrosion hole, the corrosion layer is in contact with the hard anodized film layer, the diameter of the second corrosion hole is in the range of 1000-1500nm, and the depth of the second corrosion hole is in the range of 10-300μm within range. The average shear strengths of the prepared metal-resin composites are listed in Table 1.

Example 7

(1) A commercially available 5052 aluminum alloy plate with a thickness of 1 mm was cut into rectangular pieces of 15 mm×80 mm. Put the rectangular piece into the polishing machine for polishing. Then, it was washed with absolute ethanol, then immersed in an aqueous solution of sodium hydroxide with a concentration of 2% by weight, taken out after 2 minutes, and rinsed with deionized water to obtain a pretreated aluminum alloy sheet.

(2) the aluminum alloy sheet that step (1) is obtained is put into as anode with concentration and is the oxalic acid of 20% by weight as the hard anodizing tank of electrolytic solution, with graphite carbon plate as negative electrode, under the voltage of 60V, in Electrolysis at 5°C for 15 minutes for hard anodic oxidation. The hard anodized aluminum alloy sheet is taken out and dried to obtain an aluminum alloy sheet with a hard anodized film layer on the surface. The cross-section of the aluminum alloy sheet was observed with a microscope to determine that the thickness of the hard anodized film layer was 10 μm, and the microhardness of the hard anodized film layer was 2500HV.

(3-1) Soak the aluminum alloy sheet having a hard anodized film layer on the surface obtained in step (2) in an aqueous solution (pH=12) of Na ₂ CO ₃ and NaHCO ₃ as an etching solution at a temperature of 25° C. . After 20 minutes, the aluminum alloy sheet was taken out, soaked in water for 1 minute, and then taken out and dried to obtain an alkali-etched aluminum alloy sheet.

(3-2) The alkali-etched aluminum alloy sheet obtained in step (3-1) was immersed in hydrochloric acid (pH=1) as an etching solution at a temperature of 25°C. After 5 minutes, the aluminum alloy sheet was taken out, soaked in water for 1 minute, and then taken out and dried to obtain an acid-etched aluminum alloy sheet.

The cross-section of the aluminum alloy sheet obtained by the microscope observation step (3-2) is found to be: the hard anodized film layer is distributed with first corrosion holes with a pore diameter in the range of 100-200nm, and the depth of the first corrosion holes is related to the hard anodic oxidation film layer. The ratio of the thickness of the hard anodized film layer is in the range of 0.7-1:1, and the ratio of the depth of the first corrosion hole to the thickness of the hard anodized film layer for more than 70% is 1:1; the aluminum alloy substrate is divided into A dense base layer and a corrosion layer with a second corrosion hole, the corrosion layer is in contact with the hard anodized film layer, the diameter of the second corrosion hole is in the range of 1000-1500nm, and the depth of the second corrosion hole is in the range of 10-300μm within range.

(4) Place the aluminum alloy sheet obtained in step (3-2) in an injection mold, and inject a resin composition containing glass fiber and polyethylene terephthalate (PET) on one surface of the aluminum alloy sheet (with respect to 100 parts by weight of PET, the content of glass fiber is 40 parts by weight), demoulding and cooling. Among them, the injection molding conditions include: the mold temperature is 110°C, the nozzle temperature is 300°C, the dwell time is 8 seconds, the injection pressure is 110MPa, the injection time is 4 seconds, and the delay time is 2 seconds.

Put the cooled product into a constant temperature drying oven at 120°C for 1.5 hours, and then cool it down to room temperature naturally with the furnace to obtain a metal-resin composite (the thickness of the resin layer is 5 mm), and its average shear strength is listed in Table 1. listed in .

Example 8

The aluminum alloy was surface treated and an aluminum alloy-resin composite was prepared using the same method as in Example 7, except that in step (3-1), the etching solution was an aqueous solution of ethylenediamine (pH=12).

The cross-section of the aluminum alloy sheet obtained by the microscope observation step (3-2) is found to be: the hard anodized film layer is distributed with the first corrosion holes with a pore size in the range of 10-200nm, and the depth of the first corrosion holes is related to the hard anodized film layer. The ratio of the thickness of the hard anodized film layer is in the range of 0.1-1:1, and the ratio of the depth of the first corrosion hole to the thickness of the hard anodized film layer for more than 50% is 1:1; the aluminum alloy substrate is divided into A dense base layer and a corrosion layer with a second corrosion hole, the corrosion layer is in contact with the hard anodized film layer, the diameter of the second corrosion hole is in the range of 200-2000nm, and the depth of the second corrosion hole is in the range of 0.1-400μm within range. The average shear strengths of the prepared metal-resin composites are listed in Table 1.

Example 9

The aluminum alloy was surface treated and an aluminum alloy-resin composite was prepared using the same method as in Example 7, except that in step (3-1), the etching solution was an aqueous solution of hydrazine (pH=12).

The cross-section of the aluminum alloy sheet obtained by the microscope observation step (3-2) is found to be: the hard anodized film layer is distributed with the first corrosion holes with a pore size in the range of 10-200nm, and the depth of the first corrosion holes is related to the hard anodized film layer. The ratio of the thickness of the hard anodized film layer is in the range of 0.1-1:1, and the ratio of the depth of the first corrosion hole to the thickness of the hard anodized film layer for more than 50% is 1:1; the aluminum alloy substrate is divided into A dense base layer and a corrosion layer with a second corrosion hole, the corrosion layer is in contact with the hard anodized film layer, the diameter of the second corrosion hole is in the range of 200-2000nm, and the depth of the second corrosion hole is in the range of 0.1-400μm within range. The average shear strengths of the prepared metal-resin composites are listed in Table 1.

Example 10

(1) A commercially available 5052 aluminum alloy plate with a thickness of 1 mm was cut into rectangular pieces of 15 mm×80 mm. Put the rectangular piece into the polishing machine for polishing. Then, it was washed with absolute ethanol, then immersed in an aqueous solution of sodium hydroxide with a concentration of 2% by weight, taken out after 2 minutes, and rinsed with deionized water to obtain a pretreated aluminum alloy sheet.

(2) the aluminum alloy sheet that step (1) is obtained is put into as anode with the citric acid that concentration is 20% by weight in the hard anodizing tank of electrolytic solution, with graphite carbon plate as negative electrode, under the voltage of 60V, Electrolyze for 15 minutes at 20°C for hard anodizing. The hard anodized aluminum alloy sheet is taken out and dried to obtain an aluminum alloy sheet with a hard anodized film on the surface. The cross-section of the aluminum alloy sheet was observed with a microscope to determine that the thickness of the hard anodized film layer was 21 μm, and the microhardness of the hard anodized film layer was 2000 HV.

(3-1) Soak the aluminum sheet having a hard anodized film layer on the surface obtained in step (2) in an aqueous NaOH solution (pH=13) at a temperature of 25° C. as an etching solution. After 5 minutes, the aluminum alloy sheet was taken out, soaked in water for 1 minute, and then taken out and dried to obtain an alkali-etched aluminum alloy sheet.

(3-2) The alkali-etched aluminum alloy sheet obtained in step (3-1) was immersed in phosphoric acid (pH=3) as an etching solution at a temperature of 30°C. After 20 minutes, the aluminum alloy sheet was taken out, soaked in water for 1 minute, and then taken out and dried to obtain an acid-etched aluminum alloy sheet.

The cross-section of the aluminum alloy sheet obtained by the microscope observation step (3-2) is found to be: the hard anodized film layer is distributed with the first corrosion holes with a pore size in the range of 10-200nm, and the depth of the first corrosion holes is related to the hard anodized film layer. The ratio of the thickness of the hard anodized film layer is in the range of 0.1-1:1, and the ratio of the depth of the first corrosion hole to the thickness of the hard anodized film layer of more than 60% is 1:1; the aluminum alloy substrate is divided into A dense base layer and a corrosion layer with a second corrosion hole, the corrosion layer is in contact with the hard anodized film layer, the diameter of the second corrosion hole is in the range of 200-2000nm, and the depth of the second corrosion hole is in the range of 0.1-400μm within range.

(4) Place the aluminum alloy sheet that step (3-2) obtains in the injection molding mold, and inject a resin composition containing glass fiber and nylon-66 (PA-66) on one surface of the aluminum alloy sheet (relative to 100 parts by weight PA-66, the content of glass fiber is 50 parts by weight), demoulding and cooling. Among them, the injection molding conditions include: the mold temperature is 100°C, the nozzle temperature is 300°C, the dwell time is 6 seconds, the injection pressure is 100MPa, the injection time is 5 seconds, and the delay time is 5 seconds.

Put the cooled product into a constant temperature drying oven at 120°C for 1.5 hours, and then cool it down to room temperature naturally with the furnace to obtain a metal-resin composite (the thickness of the resin layer is 5 mm), and its average shear strength is listed in Table 1. listed in .

Example 11

The same method as in Example 10 is used to carry out surface treatment on the aluminum alloy sheet and prepare a metal-resin composite, the difference is that in step (3-1), the etching solution (pH value is the same as in Example 10) also contains Na ₂ CO ₃ .

The cross-section of the aluminum alloy sheet obtained by the microscope observation step (3-2) is found to be: the hard anodized film layer is distributed with the first corrosion holes with a pore size in the range of 80-200nm, and the depth of the first corrosion holes is related to the hard anodic oxidation film layer. The ratio of the thickness of the hard anodic oxide film layer is in the range of 0.5-1:1, and the ratio of the depth of the first corrosion hole to the thickness of the hard anodic film layer of more than 60% is 1:1; the aluminum alloy substrate is divided into dense The base layer and the corrosion layer with the second corrosion hole, the corrosion layer is connected with the hard anodized film layer, the diameter of the second corrosion hole is in the range of 1000-1500nm, and the depth of the second corrosion hole is in the range of 10-300μm Inside. The average shear strengths of the prepared metal-resin composites are listed in Table 1.

Example 12

The same method as in Example 10 is used to carry out surface treatment on the aluminum alloy sheet and prepare a metal-resin composite, the difference is that in step (3-2), the etching solution (pH value is the same as in Example 10) also contains Na ₂ The molar ratio of HPO ₄ , Na ₂ HPO ₄ and H ₃ PO ₄ is 0.3:1.

Adopt the cross-section of the aluminum flake that step (3-2) obtains under the microscope, find: the hard anodized film layer is distributed with the first corroded hole that aperture is in the scope of 10-200nm, the depth of the first corroded hole and hard The ratio of the thickness of the anodized film layer is 0.1-1:1, the ratio of the depth of the first corrosion hole above 60% to the thickness of the hard anodized film layer is 1:1; the aluminum matrix is divided into a dense matrix layer and a The corrosion layer has a second corrosion hole, the corrosion layer is in contact with the hard anodized film layer, the diameter of the second corrosion hole is in the range of 400-2000nm, and the depth of the second corrosion hole is in the range of 50-200μm. The average shear strengths of the prepared metal-resin composites are listed in Table 1.

Comparing Example 1 with Comparative Examples 1-3, it can be seen that in the metal-resin composite prepared by integrally molding the surface-treated metal substrate and resin according to the present invention, the gap between the resin layer and the metal substrate The composite has higher average shear strength (that is, has higher bond strength), and thus the composite has higher structural stability.

Table 1

Numbering Average shear strength (MPa) Example 1 18.1 Example 2 17.6 Example 3 19.4 Comparative example 1 0.2 Comparative example 2 4 Comparative example 3 10.4 Example 4 23.5 Comparative example 4 14.9 Comparative example 5 7.2 Comparative example 6 5.5 Example 5 24.7 Example 6 25.3 Example 7 22.1 Example 8 20.5 Example 9 20.3 Example 10 18.8 Example 11 21.6 Example 12 20.2

Claims (39)

1. a surface treated metal base, described metal is aluminum or aluminum alloy, this metal base comprises metallic matrix and is formed at the horniness anode oxide film layer at least part of surface of described metallic matrix, and the surface distributed of described horniness anode oxide film layer has the first etch pit.

2. surface treated metal base according to claim 1, wherein, the aperture of described first etch pit in the scope of 10-200nm, preferably in the scope of 50-200nm, more preferably in the scope of 80-200nm, preferred in the scope of 100-200nm further; The ratio of the degree of depth of described first etch pit and the thickness of described horniness anode oxide film layer in the scope of 0.1-1:1, preferably in the scope of 0.2-1:1, more preferably in the scope of 0.5-1:1.

3. surface treated metal base according to claim 1 and 2, wherein, the ratio of the degree of depth of at least part of first etch pit and the thickness of described horniness anode oxide film layer is 1:1, and preferably the degree of depth of the first etch pit of more than 50% and the ratio of the thickness of described horniness anode oxide film layer are 1:1.

4. according to the surface treated metal base in claim 1-3 described in any one, wherein, described metallic matrix comprises base layer and corrosion layer, described base layer and described corrosion layer are structure as a whole, described corrosion layer connects with described horniness anode oxide film layer and is structure as a whole, and the surface distributed of described corrosion layer has the second etch pit.

5. surface treated metal base according to claim 4, wherein, the aperture of described second etch pit in the scope of 200-2000nm, preferably in the scope of 400-2000nm, more preferably in the scope of 800-1500nm.

6. the surface treated metal base according to claim 4 or 5, wherein, the degree of depth of described second etch pit in the scope of 0.1-500 μm, preferably in the scope of 10-400 μm, more preferably in the scope of 50-200 μm.

7. according to the surface treated metal base in claim 4-6 described in any one, wherein, described base layer is compacted zone.

8. according to the surface treated metal base in claim 1-7 described in any one, wherein, the thickness of described horniness anode oxide film layer is in the scope of 0.1-500 μm.

9. a surface treatment method for metal base, described metal is aluminum or aluminum alloy, and the method comprises provides metal base, and described metal base comprises metallic matrix and is formed at the horniness anode oxide film layer at least part of surface of described metallic matrix; Described metal base is carried out the first etching, to form the first etch pit in described horniness anode oxide film layer.

10. method according to claim 9, wherein, the condition of described first etching makes the aperture of described first etch pit in the scope of 10-200nm, preferably in the scope of 50-200nm, more preferably in the scope of 80-200nm, preferred in the scope of 100-200nm further; The ratio of the degree of depth of described first etch pit and the thickness of described horniness anode oxide film layer in the scope of 0.1-1:1, preferably in the scope of 0.2-1:1, more preferably in the scope of 0.5-1:1.

11. methods according to claim 9 or 10, wherein, the condition of described first etching makes the ratio of the thickness of the degree of depth of at least part of first etch pit and described horniness anode oxide film layer be 1:1, and preferably the degree of depth of the first etch pit of more than 50% and the ratio of the thickness of described horniness anode oxide film layer are 1:1.

12. according to the method in claim 9-11 described in any one, and wherein, described first etching comprises: be soaked in alkaline etching liquid by described metal base.

13. methods according to claim 12, wherein, described alkaline etching liquid is the aqueous solution containing one or more materials be selected from hydrazine derivate that water soluble hydroxide, water-soluble alkaline salt, ammonia, water-soluble amine, hydrazine and one or more hydrogen atom replaced by alkyl.

14. methods according to claim 13, wherein, described water soluble hydroxide is selected from alkali metal hydroxide, is preferably NaOH and/or potassium hydroxide; And/or

Described water-soluble alkaline salt is selected from water soluble carbonate, water soluble carbonate hydrogen salt, water-soluble phosphate, water-soluble phosphoric acid monohydric salt, water-soluble phosphoric acid dihydric salt and water-soluble borate, is preferably selected from Na ₂cO ₃, NaHCO ₃, NaH ₂pO ₄, Na ₂hPO ₄, Na ₃pO ₄and Na ₂b ₄o ₇; And/or

Described water-soluble amine is selected from ethylenediamine, diethylamide, monoethanolamine, Trimethylamine, methyl amine and dimethyl amine; And/or

Described hydrazine derivate is selected from MMH and 1,1-dimethylhydrazine.

15. methods according to claim 12, wherein, described alkaline etching liquid is alkaline buffer solution.

16. methods according to claim 15, wherein, described alkaline etching liquid is the aqueous solution containing water soluble hydroxide and water-soluble alkaline salt, or described alkaline etching liquid is the aqueous solution containing water-soluble normal salt and water soluble acid salt, or described alkaline etching liquid is the aqueous solution containing ammonia and water soluble salt of ammonia.

17. methods according to claim 16, wherein, described water soluble hydroxide is NaOH and/or potassium hydroxide; Described water-soluble alkaline salt is one or more in water soluble carbonate, water soluble carbonate hydrogen salt, water-soluble phosphate, water-soluble phosphoric acid monohydric salt, water-soluble phosphoric acid dihydric salt and water-soluble borate, be preferably water-soluble phosphoric acid dihydric salt, be more preferably one or more in sodium dihydrogen phosphate, potassium dihydrogen phosphate, ammonium dihydrogen phosphate (ADP) and aluminium dihydrogen phosphate.

18. methods according to claim 16, wherein, described alkaline etching liquid is the aqueous solution containing water soluble carbonate and water soluble carbonate hydrogen salt, or is the aqueous solution containing water-soluble phosphate and water-soluble phosphoric acid monohydric salt.

19. methods according to claim 16, wherein, described water soluble salt of ammonia is selected from NH ₄cl, (NH ₄) ₂sO ₄, NH ₄hCO ₃and NH ₄nO ₃.

20. according to the method in claim 12-19 described in any one, and wherein, the pH value of described alkaline etching liquid is 10-13.

21. according to the method in claim 10-20 described in any one, and wherein, the temperature of described alkaline etching liquid is 10-60 DEG C, is preferably 20-40 DEG C; The time of described first etching is 1-60 minute, is preferably 5-20 minute.

22. according to the method in claim 9-21 described in any one, and wherein, the method also comprises carries out the second etching, to form the second etch pit at the metal base surface connected with described horniness anode oxide film layer by the metal base through the first etching.

23. methods according to claim 22, wherein, the condition of described second etching makes the aperture of described second etch pit in the scope of 200-2000nm, preferably in the scope of 400-2000nm, more preferably in the scope of 800-1500nm.

24. methods according to claim 22 or 23, wherein, the condition of described second etching makes the degree of depth of described second etch pit in the scope of 0.1-500 μm, preferably in the scope of 10-400 μm, more preferably in the scope of 50-200 μm.

25. according to the method in claim 22-24 described in any one, and wherein, described second etching comprises: be soaked in acidic etching liquid by the metal base through the first etching.

26. methods according to claim 25, wherein, described acidic etching liquid is for containing aqueous acid, and described acid is halogen acids and/or H ₃pO ₄, be preferably HCl or H ₃pO ₄.

27. methods according to claim 25 or 26, wherein, described acidic etching liquid is also containing one or more water soluble salts, and described water soluble salt is water-soluble halogen acid salt and/or water-soluble phosphate.

28. methods according to claim 27, wherein, the mol ratio of described water soluble salt and described acid is 0.1-1:1, is preferably 0.2-0.8:1, is more preferably 0.4-0.6:1.

29. according to the method in claim 25-28 described in any one, and wherein, the pH value of described acidic etching liquid is 1-3.

30. according to the method in claim 25-29 described in any one, and wherein, the temperature of described acidic etching liquid is 20-30 DEG C, and the time of described second etching is 1-60 minute, is preferably 10-30 minute.

31. according to the method in claim 9-30 described in any one, wherein, the method of metal base is provided to comprise: metal base to be placed in electrolyte and to carry out hard anodizing, electrolyte in described electrolyte is one or more in oxalic acid, phosphate, silicate and aluminate, the condition of described hard anodizing comprises: voltage is 10-100V, is preferably 40-80V; Time is 1-60 minute, is preferably 10-30 minute; The temperature of electrolyte is 0-60 DEG C, is preferably 0-10 DEG C.

32. according to the method in claim 9-31 described in any one, and wherein, the thickness of described horniness anode oxide film layer is in the scope of 0.1-500 μm.

Surface treated metal base prepared by the method in 33. claim 9-32 described in any one.

34. 1 kinds of metal-resin complexs, described metal is aluminum or aluminum alloy, this complex comprises metal base and resin bed, described metal base is the surface treated metal base in claim 1-8 and 33 described in any one, described resin bed is attached at least part of surface of described metal base, and the part resin in described resin bed extends downwards and is filled in the first etch pit of metal base or the first etch pit and the second etch pit.

The preparation method of 35. 1 kinds of metal-resin complexs, described metal is aluminum or aluminum alloy, described metal-resin complex comprises metal base and is attached to the resin bed at least part of surface of described metal base, described metal base is the surface treated metal base in claim 1-8 and 33 described in any one, the method at least part of surface imp lantation comprised to metal base contains the composition of resin and makes fraction compositions be filled in the first etch pit of metal base or the first etch pit and the second etch pit, shaping rear formation resin bed.

Metal-resin complex prepared by 36. methods according to claim 35.

37. claims 34 or metal-resin complex according to claim 36 are preparing the application in electronic product casing.

38. 1 kinds of electronic product casings, this shell comprises metal-back body and is attached at least part of inner surface of described metal-back body and/or at least one resin piece of at least part of outer surface, it is characterized in that, described metal-back body is the metal base in claim 1-8 described in any one.

The preparation method of 39. 1 kinds of electronic product casings, the method be included in metal-back body at least part of inner surface and/or at least partly outer surface form at least one resin piece, it is characterized in that, adopt method according to claim 35 to form described resin piece.