Composite of metal and resin and method for manufacturing the same

Abstract

It is an object to manufacture a composite of a metal part and a resin composition part, which is improved so as to securely join and integrate stainless steel and a resin. A stainless steel part whose surface has been suitably roughened by chemical etching or the like can be used. An integrated product is obtained by inserting a stainless steel piece 1 with its surface treated into a cavity formed by a movable-side mold plate 2 and a fixed-side mold plate 3 of a metallic mold for injection molding 10 and injecting a specific resin. PBT, PPS or an aromatic polyamide resin can be used as the main resin component of a resin composition 4 that is used. High injection joining strength is obtained if the resin composition contains, as an auxiliary component, PET and/or a polyolefin resin in the case of PBT, a polyolefin resin in the case of PPS and an aliphatic polyamide resin in the case of an aromatic polyamide resin.

1 . A composite of metal and resin, consisting of:
 a steel part made of stainless steel, in which the surface is chemically etched after being worked into a specific shape and substantially the entire surface is covered with a ultrafine textured face in which amorphous polygons or particulates with a diameter of 20 to 70 nm are stacked on top of one another, and   a resin part made of one type of resin selected from the group consisting of a first resin composition, whose main component is a polyphenylene sulfide resin, a second resin composition whose main component is a polybutylene terephthalate resin and a third resin composition whose main component is an aromatic polyamide resin, which is directly joined by injection molding onto the ultrafine textured face of said steel part.   
   
   
       2 . The composite of metal and resin according to  claim 1 ,
 wherein the resin component of said first resin composition is a resin composition in which the polyphenylene sulfide resin is the main component and a polyolefin resin is an auxiliary component.   
   
   
       3 . The composite of metal and resin according to  claim 1 ,
 wherein the resin component of said second resin composition is a resin composition in which the polybutylene terephthalate resin is the main component and a polyethylene terephthalate resin and/or a polyolefin resin is an auxiliary component.   
   
   
       4 . The composite of metal and resin according to  claim 1 ,
 wherein the resin component of said third resin composition is a resin composition, in which a mixture of different kinds of aromatic polyamide resins is the main component, or a resin composition, in which an aromatic polyamide resin is the main component and an aliphatic polyamide resin is an auxiliary component.   
   
   
       5 . The composite of metal and resin according to  claim 2 ,
 wherein said first resin composition contains the polyphenylene sulfide resin by 70 to 97 wt % and the polyolefin resin by 3 to 30 wt %.   
   
   
       6 . The composite of metal and resin according to  claim 3 ,
 wherein said second resin composition contains the polybutylene terephthalate resin by 70 to 97 wt % and the polyethylene terephthalate resin and/or polyolefin resin by 3 to 30 wt %.   
   
   
       7 . The composite of metal and resin according to  claim 4 ,
 wherein said third resin composition contains the aromatic polyamide resin by 70 to 95 wt % and the aliphatic polyamide resin by 5 to 30 wt %.   
   
   
       8 . The composite of metal and resin according to any of  claims 1  to  7 ,
 wherein at least one type of reinforcing fiber selected from among glass fiber, carbon fiber, nylon fiber and aramid fiber, in an amount of 20 to 60 wt %, and   at least one type of filler selected from among calcium carbonate, magnesium carbonate, silica, talc, clay and glass powder   are contained in said one type of resin selected from the group consisting of said first resin composition, said second resin composition and said third resin composition.   
   
   
       9 . A method for manufacturing a composite of metal and resin, comprising:
 a shaping step of shaping a substrate composed of stainless steel by mechanical working;   a liquid treatment step including chemical etching for providing the surface of said shaped substrate with a ultrafine textured face, in which protrusions with a height, width and length of at least 10 nm rise up at a spacing period of at least 10 nm, and for obtaining a surface roughness, in which the mean width (RSm) of profile elements made up of said ultrafine textured face is 0.5 to 10 μm and the maximum height of roughness (Rz) is 0.2 to 5 μm;   an insertion step of inserting said substrate that has undergone the liquid treatment into a metallic mold for injection molding;   an injection step of injecting onto the surface of said inserted substrate one type of resin; and   an integration step of integrating said substrate with said one type of resin by said injection,   said one type of resin being selected from: a first resin composition in which a polyphenylene sulfide resin is the main component and a polyolefin resin is an auxiliary component,   a second resin composition in which a polybutylene terephthalate resin is the main component and a polyethylene terephthalate resin and/or a polyolefin resin is an auxiliary component, and   a third resin composition that is a resin composition in which a mixture of different kinds of aromatic polyamide resins is the main component, or a resin composition in which an aromatic polyamide resin is the main component and an aliphatic polyamide resin is an auxiliary component.   
   
   
       10 . A method for manufacturing a composite of metal and resin, comprising:
 a shaping step of shaping a substrate composed of stainless steel by mechanical working;   a chemical etching step of immersing the substrate that has undergone said shaping step in a sulfuric acid aqueous solution to chemically etch the surface thereof;   an insertion step inserting the substrate that has undergone said chemical etching into a metallic mold for injection molding;   an injection step of injecting onto the surface of said inserted substrate one type of resin; and   an integration step of integrating said substrate with said one type of resin by said injection,   said one type of resin being selected from the group consisting of:   a first resin composition in which a polyphenylene sulfide resin is the main component and a polyolefin resin is an auxiliary component,   a second resin composition in which a polybutylene terephthalate resin is the main component and a polyethylene terephthalate resin and/or a polyolefin resin is an auxiliary component, and   a third resin composition that is a resin composition, in which a mixture of different kinds of aromatic polyamide resins is the main component, or a resin composition, in which an aromatic polyamide resin is the main component and an aliphatic polyamide resin is an auxiliary component.   
   
   
       11 . A method for manufacturing a composite of metal and resin, comprising:
 a shaping step of shaping stainless steel by mechanical working;   a chemical etching step immersing the stainless steel substrate that has undergone said shaping step in a sulfuric acid aqueous solution to chemically etch the surface thereof;   an oxidation step of immersing the substrate that has undergone said chemical etching step in a nitric acid aqueous solution;   an insertion step of inserting the substrate that has undergone said oxidation step into a metallic mold for injection molding;   an injection step of injecting onto the surface of the inserted substrate one type of resin; and   an integration step of integrating said substrate with said one type of resin by said injection,   said one type of resin being selected from the group consisting of:   a first resin composition in which a polyphenylene sulfide resin is the main component and a polyolefin resin is an auxiliary component,   a second resin composition in which a polybutylene terephthalate resin is the main component and a polyethylene terephthalate resin and/or a polyolefin resin is an auxiliary component, and   a third resin composition that is a resin composition, in which a mixture of different kinds of aromatic polyamide resins is the main component, or a resin composition in which an aromatic polyamide resin is the main component and an aliphatic polyamide resin is an auxiliary component.