Method for integrally molding metal and resin and metal-resin composite structure obtainable by the same

1. A method for integrally molding a metal and a resin, comprising:

forming a nanopores on a surface of a metal sheet;

immersing the metal sheet in an etching solution to form corrosion pores on an outer surface of the metal sheet, thereby to form a double-layer pore structure including the corrosion pores and the nanopores, the corrosion pores being in communication with the nanopores, wherein the corrosion pores have a larger diameter than the nanopores;

melting a thermoplastic resin; and

injection molding the thermoplastic resin onto the surface of the metal sheet through the nanopores and the corrosion pores, wherein the thermoplastic resin composition is fixedly attached to the aluminum alloy substrate,

wherein the thermoplastic resin is a mixture of a main resin and a polyolefin resin, the main resin is a mixture of polyphenylene oxide and a polyamide, and the polyolefin resin has a melting point of about 65° C. to about 105° C.

2. The method according to claim 1 , wherein forming the nanopores on the surface of the metal sheet comprises:

anodizing the surface of the metal sheet to form an oxide layer on the surface of the metal sheet, wherein the oxide layer includes the nanopores.

3. The method according to claim 2 , wherein the oxide layer has a thickness of about 1 μm to about 10 μm, and the nanopores have a diameter of about 10 nm to about 100 nm and a depth of about 0.5 μm to about 9.5 μm.

4. The method according to claim 2 , wherein anodizing the surface of the metal sheet comprises:

placing a pretreated metal sheet as an anode in a H 2 SO 4 solution with a concentration of about 10 wt % to about 30 wt %; and

electrolyzing the metal at a temperature of about 10° C. to about 30° C. at a voltage of about 10V to about 100V for about 1 minute to about 40 minutes to form the oxide layer with a thickness of about 1 μm to about 10 μm on the surface of the metal sheet.

5. The method according to claim 1 , wherein the corrosion pores have a diameter of about 200 nm to about 2000 nm and a depth of about 0.5 μm to about 9.5 μm.

6. The method according to claim 1 , wherein the etching solution is a solution which corrodes the oxide layer.

7. The method according to claim 1 , wherein based on 100 weight parts of the thermoplastic resin, the amount of the main resin is about 70 weight parts to about 95 weight parts, and the amount of the polyolefin resin is about 5 weight parts to about 30 weight parts.

8. The method according to claim 7 , wherein based on 100 weight parts of the thermoplastic resin, the thermoplastic resin further contains about 1 weight part to about 5 weight parts of a flow improver, and the flow improver is a cyclic polyester.

9. The method according to claim 1 , wherein in the main resin, the weight ratio of polyphenylene oxide to the polyamide is about 3:1 to about 1:3.

10. The method according to claim 1 , wherein the polyolefin resin is a grafted polyethylene.

11. The method according to claim 1 , wherein the metal is at least one selected from a group including aluminum, stainless steel, and magnesium.

12. A method for integrally molding a metal and a resin, comprising:

A) forming nanopores on a surface of a metal sheet by anodizing the surface of the metal sheet to form an oxide layer on the surface of the metal sheet, wherein the oxide layer includes the nanopores;

B) immersing the metal sheet formed with the oxide layer on the surface thereof in an etching solution to form corrosion pores on an outer surface of the oxide layer, thereby to form a double-layer pore structure including the corrosion pores and the nanopores, the corrosion pores being in communication with the nanopores, wherein the corrosion pores have a larger diameter than the nanopores;

C) melting a thermoplastic resin; and

D) injection molding the thermoplastic resin onto the surface of the metal sheet formed with the nanopores and corrosion pores wherein the thermoplastic resin composition is fixedly attached to the aluminum alloy substrate,

wherein the thermoplastic resin is a mixture of a main resin and a polyolefin resin, the main resin is a mixture of polyphenylene oxide and a polyamide, and the polyolefin resin has a melting point of about 65° C. to about 105° C., and wherein the nanopores have a diameter of about 10 nm to about 100 nm and the corrosion pores have a diameter of about 200 nm to about 2000 nm.