Integrated composite of metal and resin

Abstract

To provide a composite made by ejection bonding of a non-aluminum metal piece such as steel material, SUS steel, and titanium alloy, and a high crystallinity thermoplastic resin, where bonding force between a metal part and a resin molded product part is sufficiently large.SOLUTION: An integrated composite of metal and resin is made by bonding a surface of a metal material and a crystalline thermoplastic resin composition through ejection molding operation. The metal material is one kind selected from steel material, stainless steel, titanium alloy, etc. The crystalline thermoplastic resin composition has heat resistance against a melting point of 200°C or higher. The ejection bonding is performed in a state in which a water-soluble high molecular weight amine-based compound is adsorbed on a surface before the ejection bonding. A bonded part of the integrated composite has shearing bond strength of about 39 MPa or more. The high molecular weight amine-based compound is triethanolamine or tetra-sodium salt of EDTA.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] This invention relates to an integrated composite material of metal and resin. More specifically, it relates to an integrated composite material of metal and resin manufactured by injection bonding of a non-aluminum metal material such as steel or a Ti alloy and a heat-resistant thermoplastic resin composition, which can be used as a component or structural material for machinery, equipment, etc. [Background technology]

[0002] Bonding technologies that strongly join metals and synthetic resins are in demand not only in the manufacturing of parts for automobiles, home appliances, and industrial equipment, but also in a wide range of industrial fields, and many adhesives have been developed for this purpose. Such bonding technologies, including adhesives, are fundamental technologies in all manufacturing industries. Bonding methods that do not use adhesives have also been researched and various proposals have been made. Among these, there are "NMT (abbreviation for Nano Molding Technology)" and "New NMT (abbreviation for New Nano Molding Technology)" which were developed, proposed, and named by the inventors of the present invention (hereinafter referred to as "the inventors"). NMT is a bonding technology that joins an Al alloy piece having a chemically treated surface with a resin composition whose main component is a crystalline thermoplastic resin. This bonding is a composite manufacturing technology in which molten crystalline thermoplastic resin is injected into an Al alloy piece that has been pre-inserted into an injection molding die, molding the resin portion and simultaneously bonding the resin molded product and the Al alloy piece to create a single composite. Furthermore, the improved new NMT is a joining technology that extends to all metal types, not just Al alloy pieces, and differs from NMT in that the basic theory of the surface treatment method for metals performed before insertion into the injection molding die is different. The present inventors refer to the joining of solid materials such as metals and thermoplastic resins by injection molding, and the technology related thereto, as "injection joining" or "injection joining technology."

[0003] Using this NMT and the new NMT as basic technologies, injection-molded composites (integrated composites) made from aluminum alloy material and a specific PPS-based resin composition exhibit a high bonding strength of approximately 40 MPa between the metal and resin. This bonding strength of the injection-molded composite hardly decreases even after being exposed to 8,000 hours at 85°C and 85% humidity. Furthermore, it has been found that if a specific shape and structure is adopted for this injection-molded composite, it can withstand a 3,000-cycle temperature shock test at -50°C / +150°C (Patent Documents 4 and 5). Subsequent research and development have revealed the following about injection-molded composites made from aluminum alloy material and a specific polyamide-based resin composition: This injection-molded composite exhibits a very strong bonding strength of approximately 50-55 MPa between the metal and resin. Moreover, if the injection-molded composite is coated with an oil-based agent, rust-preventive paint, etc., the bonding strength between the metal and resin hardly decreases even after being exposed to 8,000 hours at 85°C and 85% humidity. Furthermore, it has been found that if the resin structure of the injection-molded product is given an appropriate shape, it can withstand a 3,000-cycle temperature shock test at -50°C / +150°C (Patent Document 13). Thus, injection-molded products using aluminum alloy material and heat-resistant crystalline thermoplastic resins, such as engineering plastics or super engineering plastics, can already be produced that are sufficiently practical to be used in environments with high humidity, temperature changes, and tens of thousands of cycles of temperature shock.

[0004] On the other hand, the following results were obtained for composites formed by injection bonding of non-aluminum metal materials and crystalline thermoplastic resins. Specifically, the question was what the bonding strength of the injection-bonded product would be when "SGX120 (manufactured by Tosoh Corporation (headquarters: Tokyo, Japan), product name: Susteel)" was used as the resin material for this composite as a PPS-based resin, and AZ31Mg alloy, C1100 copper, SUS304 stainless steel, SUS430 stainless steel, SPCC (cold-rolled steel sheet), 64Ti alloy, etc. were used as the non-aluminum metal material. In the case of injection-bonded products (test pieces shown in Figure 1) in which each of the non-aluminum metal materials was subjected to the aforementioned new NMT treatment and bonded to the above-mentioned PPS-based resin, a shear bonding strength of approximately 40 MPa was obtained between the metal and resin. In short, it has already been found that by using the above-mentioned PPS-based resin "SGX120" as the resin material and employing the injection bonding technology known as NMT or New NMT, which is a chemical conversion treatment proposed by the inventors, the bonding force between the resin part and the metal piece can be made approximately 40 MPa, regardless of whether the metal is an aluminum alloy or a non-aluminum metal. These methods are already widely used and in practical applications.

[0005] Furthermore, when the above resin material is replaced with a polyamide resin instead of the PPS-based resin "SGX120", and "CM3506G50 (manufactured by Toray Industries, Inc. (Headquarters: Tokyo, Japan))" is used as the resin material, the shear bond strength of the injection-molded bonded product (test piece in Figure 1) obtained when an Al alloy is used as the metal material is very high, at 50-55 MPa (Patent Document 12). However, with non-aluminum metal materials, the inventors estimate that the maximum value is around 40 MPa, and the bond strength is clearly weaker than that of the Al alloy material. The reason why such a high bond strength exceeding approximately 50 MPa was obtained in the injection-molded bonded product with the Al alloy is that the optimal resin composition was found through trial and error testing of the resin composition ratio, such as optimizing the mixing ratio of semi-aromatic polyamide resin and aliphatic polyamide resin as the resin material for injection molding. Therefore, at this point, the inventors selected "CM3506G50," a polyamide resin, as the best polyamide resin material for injection bonding. Accordingly, the inventors considered "CM3506G50" to be the most suitable resin composition currently available as a commercially available polyamide resin for injection bonding, and injected this resin with various non-aluminum metals that had undergone the aforementioned new NMT treatment. However, the shear bond strength of the various injection-bonded products obtained was extremely low.

[0006] Let me explain this point in more detail. Specifically, using the new NMT treatment method, non-aluminum metals such as SUS304 stainless steel, SUS430 stainless steel, SPCC (cold-rolled steel sheet), and 64Ti alloy were chemically treated and then joined to the PPS-based resin "SGX120" in an injection bonding operation. The shear bonding strength of the injection-bonded products obtained in this bonding operation all showed approximately 40 MPa, so it was judged that the new NMT treatment method, which is the chemical treatment method for each metal piece, is a well-improved chemical treatment method. In other words, specifically, when the surface chemical treatment is faithfully performed according to the "new NMT" theory described later, the only conditions are that it has a fine uneven surface with a period of 1 to 5 μm and an ultrafine uneven surface with a period of 10 to 100 nm. However, in the experiment, at this point, an operation was also performed to add a rough surface with a period of 20 to 50 μm, that is, a matte surface. This improved procedure increased the bonding strength between the metal and resin, resulting in the aforementioned shear bonding strength of approximately 40 MPa. In short, by forming a fine uneven surface on a large, rough matte surface, and then forming an ultrafine uneven surface on top of this fine uneven surface, it was possible to increase the density (surface area) of the ultrafine uneven surfaces with a period of 10-100 nm, which are essential to this shape. This new NMT treatment, which forms the most improved surface shape, was applied to various non-aluminum metal types, and then injection-bonded with the polyamide resin "CM3506G50".

[0007] However, in this injection bonding process, even the 64Ti alloy with the highest shear bonding strength only achieved about 45 MPa. Moreover, when multiple injection-bonded products were simultaneously injected and then subjected to tensile fracture, the bonding strength varied considerably from individual to individual, ranging from approximately 20 to 45 MPa. In short, these experimental results show that securing high injection bonding strength is far more difficult when using polyamide resins than when using PPS resins. This was not the case when using NMT-treated Al alloy pieces, and in other words, it reinforced the inventors' own reasoning that "new NMT-treated products should fundamentally have lower injection bonding strength than NMT-treated products" (details on the difference between NMT and new NMT will be discussed later). Similar cases to those observed with the injection bonding technology using the polyamide resin "CM3506G50" were also observed with polyetheretherketone resin (hereinafter referred to as "PEEK") and polyaryletherketone resin (hereinafter referred to as "PAEK"). Specifically, when PEEK and PAEK resin compositions were used as injection molding resins, and Al alloys that had undergone NMT-type treatment (e.g., NMT7, NMT8 treatment, etc.) as improved metallic materials were used, the shear joint strength of the injection-molded products (test specimens shown in Figure 1) all reached approximately 50 MPa or higher, and some even reached 55-57 MPa.

[0008] On the other hand, when injection-molded joints are made using non-aluminum metals, the highest shear joint strength was 20-50 MPa for 64Ti alloy, and some test pieces showed high joint strength values, but there was a large variation, and stainless steels such as SUS304 showed considerably lower joint strength, in the 10 MPa range. In short, if we list the types of resins in order of ease of manufacturing injection-molded joints with high joint strength, it can be roughly estimated that they are PBT-based, PPS-based, polyamide-based, and PAEK-based, including PEEK. Based on the above premises, the inventors' experience and knowledge indicate that PBT-based and PPS-based resins have already reached a level of perfection, achieving the highest level of joint strength, but polyamide-based resins have reached a level of perfection with Al alloys but are not yet perfect with non-aluminum metal species, and PAEK-based resins have reached a level of perfection with Al alloys but are still far from perfect with non-aluminum metals. In other words, with Al alloys that can be treated with NMT-type surface chemical conversion treatment, it is possible to reach the level of PEEK and PAEK-based resins, which have the highest heat resistance among the high-strength resins that are commonly used in practical applications. Regarding non-aluminum metal species using the new NMT surface treatment, the process has been completed up to PPS-based resins, but there is still room for improvement from the triamide-based resins onward, and as for PAEK-based resins, the result shows that there is still a long way to go.

[0009] The following describes the outlines of the NMT, NMT2, NMT5 to NMT8 as proposed by the present inventors and referred to in this invention. (NMT (abbreviation for Nano molding technology)) The aforementioned NMT injection bonding technology using Al alloy has been defined by the inventors as having the following four or five necessary conditions for its establishment. First, regarding the Al alloy side, the following conditions (1) and (2) are necessary conditions. The chemical treatment of the Al alloy surface to satisfy these two points has been named "NMT treatment". (1) The entire surface is covered with ultrafine recesses with a diameter of 20 to 50 nm. (2) And, a water-soluble amine compound is chemically adsorbed onto its surface layer. Next, regarding the resin composition to be injected, the following two or three points are necessary conditions. (3) The resin composition to be used is a resin composition mainly composed of a highly crystalline thermoplastic resin. (4) The highly crystalline thermoplastic resin undergoes a chemical reaction with amine molecules at high temperatures. (5) The resin composition includes, as a secondary component resin, a resin that is compatible with the main component resin, or, even if it is not compatible with the main component resin, a resin that can be made compatible or partially compatible with the main component resin by adding the third component resin. Conditions (1) to (4) above are essential requirements, and the injection bonding strength will be further increased if condition (5) is added. The NMT that was put into practical use was one that satisfied conditions (1) to (5) above and selected hydrated hydrazine as the amine compound in (2) above.

[0010] (NMT2, NMT5~NMT8) The inventors discovered that a composite with strong bonding strength can be obtained by injection bonding a polybutylene terephthalate (hereinafter referred to as "PBT") resin composition to an NMT-treated Al alloy. Subsequently, as disclosed in Patent Document 1, the inventors discovered that a PPS resin composition can also be injection bonded to an NMT-treated Al alloy. Next, in Patent Document 2, the inventors disclosed a technique for injection bonding a polyamide resin composition to an NMT-treated Al alloy. Then, in Patent Document 3, the inventors developed the "NMT2" treatment method by improving the surface treatment method of Al alloy, and discovered that the injection bonding strength between this treated material and the aforementioned PBT resin, PPS resin, and polyamide resin is improved. In particular, the shear bonding strength of the material using PPS resin is approximately 40 MPa, and it was shown for the first time that the shear bonding strength of the injection-bonded material is maintained at approximately 37-40 MPa even when the injection-bonded material is left at a temperature of 85°C and 85% humidity for 6,000 to 8,000 hours or more, resulting in a metal-resin integrated material with the highest degree of humidity and heat resistance. The inventors named this technology NMT2.

[0011] NMT2 was recognized as the highest-performing injection bonding technology for Al alloys and PPS-based resins, but subsequent tests and experiments revealed that problems still existed. Specifically, when Al alloys were NMT2-treated and stored for more than 10 days before the PPS-based resin injection bonding process, the heat and humidity resistance of the shear bond strength decreased. NMT2 was most extensively used in the manufacture of Al alloy casings for smartphones. The production volume required for this actual production increased sharply, and although numerous injection molding machines were installed to handle the injection bonding process, it became difficult to process all the NMT2-treated materials within 10 days of completing the NMT2 treatment. To address this, the NMT2 treatment method was improved, and chemical conversion treatment methods named NMT5, NMT7, NMT8, etc., for various Al materials were developed and proposed. When these new treatment methods are used, the aforementioned effective storage period becomes effective for more than 4 weeks, even in summer (Patent Document 4). In addition, the inventors investigated the shape of injection-molded products of Al alloy treated with the NMT type described in Patent Document 4 and PPS-based resin, and found a shape in which, when the resin is shaped in a specific way, the bonding strength is not adversely affected even after undergoing a 3,000-cycle temperature shock test at -50°C / +150°C, and this shape is disclosed (Patent Document 5).

[0012] (New NMT (abbreviation for New Nano molding technology)) As mentioned above, in NMT and subsequent NMT-type injection bonding technologies, the final step of the surface treatment involves chemically adsorbing amine molecules. Since Al alloy materials strongly chemically adsorb amine molecules, this NMT-like chemical treatment is effective, and this is a key technology in NMT, NMT2 to NMT8 injection bonding technologies. That is, metal materials other than aluminum alloy materials do not chemically adsorb amine molecules or the adsorption is weak, and therefore NMT treatment does not exhibit its effect. However, research into improving the injection bonding strength in NMT has led to progress in research and development of the resin compositions used, and by using improved resin compositions for injection bonding, injection bonding has become possible with only chemical conversion treatment to form appropriate fine irregularities on the surface shape of various metal materials, even in the absence of chemically adsorbed amine molecules. In other words, the present inventors have invented and disclosed a new NMT technology that enables injection bonding of various metal materials and resin compositions even with surface-treated materials that do not contain adsorbed amine molecules (Patent Documents 6 to 10). In short, the new NMT is an injection bonding technology that can handle almost all types of practical metals supplied to the market, such as Mg alloys, Al alloys, copper and copper alloys, stainless steel, general steel materials, and special steel sheets, and the highly crystalline thermoplastic resin used is the same as the injection bonding resin used for NMT.

[0013] The conditions for establishing "New NMT" as used here, according to the inventors' definition, are the following five necessary conditions. Of these, the following three are necessary conditions regarding the metal material used. The chemical treatment that satisfies these three conditions (hereinafter (1) to (3)) is called "New NMT treatment." That is, (1) The metal material has a rough surface with a period of 0.8 to 10 μm. (2) The rough surface has a fine uneven surface shape with a period of 5 to 300 nm (preferably 50 to 100 nm), and (3) The surface layer is covered with a thin layer of hard ceramic material such as a metal oxide or metal phosphor oxide. Furthermore, the following two conditions are necessary for the resin being injected: (4) Use of a resin composition mainly composed of a highly crystalline thermoplastic resin. (5) In addition to the highly crystalline thermoplastic resin as the main component, the resin composition contains, as a secondary component resin, a resin that can be compatible with the main component resin or a resin that is incompatible with the main component resin, and further contains, as a third component resin, a resin that promotes partial compatibility with the main component resin.

[0014] The new NMT was developed for all metal species, but the most remarkable technical achievements were demonstrated for Al alloys. That is, the inventors developed and proposed the NMT5-Ano and NMT7-Ano treatment methods, which include anodic oxidation treatment, a surface treatment for Al alloys, and further, the NMT5-Oxy and NMT7-Oxy treatment methods that include hydrogen peroxide treatment at the final stage. In these methods, the injection bonded products with PPS-based resins have extremely high moisture and heat resistance of the bonding strength between the metal and the resin, and the storage time of the intermediate material from surface treatment to injection bonding is 4 weeks or more. Even after several months or one year, good products were obtained without problems (Patent Document 4). Also, for titanium alloys, stainless steels, and general steel materials, new NMT treatment methods for each of them were improved, and high shear bonding strength can be obtained in injection bonding using PBT and PPS-based resins.

Prior Art Documents

Patent Documents

[0015]

Patent Document 1

Patent Document 2

Patent Document 3

Patent Document 4

Patent Document 5

Patent Document 6

Patent Document 7

Patent Document 8

[0016] This invention, in the context of the background technology described above, develops a method for increasing the bonding strength between a non-aluminum material and a resin composite. As mentioned above, regarding the surface shape of the metal side, the inventors believe that the surface shape formed by the new NMT treatment method is the optimal surface shape. Regarding the injection bonding strength between polyamide resins and non-aluminum metals, at present, we have found the commercially available polyamide resin "CM3506G50" which is optimal for injection bonding. Therefore, the only remaining challenge for improvement is a fundamental improvement of the surface treatment method for the metal side. In other words, for various non-aluminum metal materials, much effort has already been made to improve the new NMT treatment method for injection bonding, and surface roughening with a period of several tens of micrometers, fine surface unevenness with a period of several micrometers, and ultrafine surface unevenness with a period of 10 to 100 nm have already been performed to increase the actual surface area. Therefore, the present invention aims to bridge the gap between NMT treatment and the new NMT treatment method, and it was determined that the only remaining option is to add an adsorption operation of amine molecules to the new NMT-treated product. In short, the "innovative idea" to be implemented is to somehow forcibly adsorb large amounts of amine molecules and amine compounds onto non-aluminum metal materials that do not have a clear chemical adsorption capacity for amine molecules. Specifically, this involves physically adsorbing large amounts onto the metal surface, resulting in a metal-treated piece that exhibits a phenomenon similar to that of an NMT-treated product.

[0017] Therefore, regarding methods to increase the amount of adsorption, if the metal material to be injection-bonded is not an aluminum metal, strong chemical adsorption cannot be expected, so methods using physical adsorption operations can be considered. Specifically, the substances to be physically adsorbed are water-soluble amine molecules, and the inventors have broadened the definition of this to include both water-soluble amine molecules and amine compounds. Furthermore, they initially tried to find the heaviest possible substances, that is, compounds with large molecular weight and mass, and generally speaking, molecules with high boiling points tend to have a larger amount of physical adsorption. Subsequently, they decided to include substances such as sodium soap or sodium salts of amino acids, for which boiling point measurement is generally impossible. Among the selected substances, they speculated that if a certain amount of adsorption could be obtained at room temperature, it would be able to withstand the high temperature of about 150°C that the metal piece will experience when inserted into the injection bonding mold during the injection bonding process. In addition, when using PEEK resins, PAEK resins, etc. as injection bonding resins, the mold temperature becomes 180-190°C. Under such high temperatures, if amine molecules or compounds physically adsorbed onto non-aluminum metal pieces are present, they may decompose and desorb or undergo thermal decomposition before the injection bonding operation begins. However, it was predicted that amine molecules or compounds capable of withstanding such high temperatures would exist if accurately searched for. In NMT, hydrated hydrazine (N2H4·H2O: molecular weight 50) is used as the water-soluble amine molecule, and this is chemically adsorbed onto an Al alloy piece. This Al alloy piece is then injection-bonded to a PEEK-based resin, easily achieving a shear bond strength of 50 MPa or more.

[0018] In a prior invention proposed by the present inventors, it was found that Al alloys and amine molecules strongly chemisorb, and the mold temperature at that time was 180-190°C. Therefore, if the adsorption force is strong, even amine molecules will not easily desorb even at nearly 200°C. For this reason, heavy amine compounds were selected, and even if their chemisorbing force is very weak, the inventors relied on van der Waals forces (intermolecular attractive forces) which are proportional to the mass. In short, the inventors devised an injection bonding technology that utilizes this physicoadhesive phenomenon. The present inventors named this new technology a new type of NMT, or "SNMT (an abbreviation for Special Nano molding technology)" in this invention (details will be described later).

[0019] The present invention aims to make the resulting metal-resin injection-molded composites useful not only as bodywork and component parts for mobile machinery such as automobiles, but also as materials that can be used in all kinds of machinery and equipment. On the other hand, the aforementioned injection-molded composites of PPS resin and Al alloy (Patent Documents 4 and 5) were intended for use in mobile machinery such as automobiles. This is because these injection-molded composites are lightweight, have a high bonding strength of approximately 40 MPa between the Al alloy and the resin molded product, and the bond is resistant to moisture and heat, possessing long-term durability that can withstand temperature shock tests of several thousand cycles. Therefore, the inventors thought that if the invention of the injection-molded composite using PPS resin and Al alloy could be used as is for automobiles, they would be perfectly satisfied, and intended to complete their research and development with the inventions proposed in Patent Documents 4 and 5. The most important thing for component parts of mobile machinery is high strength and lightweight, and therefore all efforts were put into the use of Al alloy, and the best example of this was the technology described in Patent Document 4. However, they failed to attract the expected interest from those in the automotive manufacturing industry, which they considered their most important target.

[0020] The composites using PPS-based resins described in Patent Documents 4 and 5 were not adopted by automobile manufacturers, etc. One reason for this is the fire accidents that occur in automobile accidents, etc. Polyamide resins and polyolefin resins used in bumpers, resin gasoline tanks, etc., both burn without emitting toxic gases. In contrast, PPS produces sulfur dioxide gas, and PVC resin produces hydrochloric acid gas. Drivers and passengers left in a burning car would inhale toxic gases. The inventors changed the commonly used resin material from the nearly completed PPS-based resin and metal composite to a polyamide-based resin, etc. The present invention was invented against the above background and aims to achieve the following objectives. The object of the present invention is to provide an integrated composite of metal and resin in which a non-aluminum metal material such as steel, stainless steel, or titanium is bonded to a crystalline thermoplastic resin with a shear bond strength of approximately 39 MPa or more. Another object of the present invention is to provide an integrated metal-resin composite in which an optimal compound is found to be adsorbed onto the bonding surface of a metal material in order to firmly bond a non-aluminum metal material such as steel, stainless steel, or titanium material to a crystalline thermoplastic resin. Another object of the present invention is to provide a metal-resin composite in which a non-aluminum metal material such as steel, stainless steel, or titanium and a crystalline thermoplastic resin can withstand a temperature shock test of 3,000 cycles at -50°C / +150°C. [Means for solving the problem]

[0021] To solve the aforementioned problems, the present invention employs the following means. The integrated metal-resin composite of the present invention 1 is In a metal-resin composite formed by joining a metal material having a surface-treated surface and the surface to a crystalline thermoplastic resin composition by injection molding, The aforementioned metal material is one selected from steel, titanium alloy, and stainless steel, and its surface is chemically treated. The surface after the chemical conversion treatment was found to have a rough surface with a period of 20-50 μm as observed with a 10000x electron microscope, and on the rough surface, 0. 8 It has a fine uneven surface with a period of ~5 μm, and On the aforementioned fine uneven surface Observation with a 100,000x electron microscope reveals a micro-surface with a period of 10-100 nm, exhibiting a fine surface texture. The aforementioned crystalline thermoplastic resin composition has heat resistance with a melting point of 200°C or higher. The crystalline thermoplastic resin composition is integrated by the injection molding operation while a water-soluble high molecular weight amine compound is adsorbed onto the aforementioned surface. The crystalline thermoplastic resin composition has a resin composition containing 70% by weight or more of polyphenylene sulfide, 30% by weight or less of modified polyolefin resin, and 5% by weight or less of a third component resin, and also contains 15 to 25% by weight of glass short fibers. The shear joint strength is characterized by having 39 to 43 MPa.

[0022] The integrated metal-resin composite of the present invention 2 is In a metal-resin composite formed by joining a metal material having a surface-treated surface and the surface to a crystalline thermoplastic resin composition by injection molding, The aforementioned metal material is one selected from steel, titanium alloy, and stainless steel, and its surface is chemically treated. The surface after the chemical conversion treatment was found to have a rough surface with a period of 20-50 μm as observed with a 10000x electron microscope, and on the rough surface, 0. 8 It has a fine uneven surface with a period of ~5 μm, and On the aforementioned fine uneven surface Observation with a 100,000x electron microscope reveals a micro-surface with a period of 10-100 nm, exhibiting a fine surface texture. The aforementioned crystalline thermoplastic resin composition has heat resistance with a melting point of 200°C or higher. The crystalline thermoplastic resin composition is integrated by the injection molding operation while a water-soluble high molecular weight amine compound is adsorbed onto the aforementioned surface. The crystalline thermoplastic resin composition is a resin composition containing 10% by weight or more of semi-aromatic polyamide and 90% by weight or less of aliphatic polyamide, and is a composition in which glass short fibers account for 25% by weight or more of the total. The shear joint strength is characterized by having 45 to 65 MPa.

[0024] The integrated metal-resin composite of the present invention 4 is the same as the present invention 1 or 3 In the integrated composite of metal and resin, the high molecular weight amine compound is characterized by being triethanolamine or an EDTA derivative. The integrated metal-resin composite of the present invention 5 is the same as the present invention 1 or 3 The material is an integrated composite of metal and resin, wherein the steel material is general steel, and the stainless steel is a special steel including austenitic stainless steel and ferritic stainless steel.

[0028] The present invention described above will now be explained in detail, including its configuration and technical background. [Regarding the "SNMT (abbreviation for Special Nano mold technology)" of this invention] This invention will now explain the novel injection bonding technology proposed in this invention, known as "Novel NMT," or "SNMT" in this invention. Simply put, SNMT is a treatment method for non-aluminum metal materials for injection bonding, and a chemical conversion treatment method for metal surfaces. In the inventors' view, strong chemical adsorption of amine molecules is clearly observed only in Al alloys, and therefore the aforementioned NMT treatment method is only effective for Al alloys. For non-aluminum metal materials, the inventors believed that only the aforementioned new NMT treatment method could be used for injection bonding, but its bonding strength did not reach the ideal level. To overcome this, this invention adopts a strategy of increasing physical adsorption by increasing the molecular weight or formula weight of adsorbed substances on the metal surface, rather than relying on chemical affinity, which is too weak to be present. This strategy has been successful. This measure to increase physical adsorption capacity is a chemical treatment method named "New NMT" or "SNMT" as described in this section, and is a necessary condition for the metal surface, the resin used, etc.

[0029] The conditions for achieving "SNMT" as defined in this invention are the following six necessary conditions. Of these, the following four are necessary conditions regarding the metal material used. The chemical treatment that satisfies these four conditions (requirements (a) to (d) below) is called "SNMT treatment". That is, (a) The metal material has a rough surface with a period of 20-50 μm, in other words, a "matte surface". (b) The rough surface has fine irregularities with a period of 0.8 to 5 μm. (c) The fine uneven surface has an ultrafine uneven surface with a period of 10 to 100 nm, and (d) The surface layer is covered with a thin layer of hard ceramic material such as a metal oxide or metal phosphorus oxide, and further adsorbed thereon high boiling point or large molecular weight amine molecules or amine compounds having multiple polar groups. The injection resin side requires the following two conditions: (e) The resin composition used is a resin composition mainly composed of a highly crystalline thermoplastic resin, and (f) The resin composition contains, in addition to the main component, a highly crystalline thermoplastic resin, as a secondary component resin, a resin that is compatible with the main component resin, or, even if it is a resin that is not compatible with the main component resin, a third component resin that further promotes compatibility with the main component resin, even if only partially.

[0030] The three requirements above (a, b, and c) add a surface roughening treatment (requirement a) to create a matte surface, in addition to (1) and (2) of the aforementioned new NMT treatment. However, current new NMT treated materials for various metals, whether Al alloys or non-aluminum metals, are already matte-finished in order to improve the perfection of injection bonding strength, so this merely confirms and confirms that practice. Furthermore, requirement (d) above, in addition to requirement (3) of the new NMT treatment requiring a thin layer of ceramic material on the surface of the metal material, also requires the adsorption of high molecular weight amine molecules and compounds, which is the greatest feature of this treatment method. There are two types of high molecular weight amine molecules and high formula weight amine compounds whose effectiveness has been confirmed: the lightweight type is triethanolamine, and the other is a heavyweight derivative of EDTA (ethylenediaminetetraacetic acid), specifically the 4Na salt, which is expressed as EDTA·4Na, EDTA·2Na(2Na), or EDTA(4Na). In addition to the above, many other amino acids can be considered as high molecular weight amine molecules or amine compounds in this invention. In practice, the performance can be confirmed by injection bonding tests using polyamide resin compositions or PEEK resin compositions for injection bonding using non-aluminum metal pieces, and commercialization is possible if even one product proves practical.

[0031] In other words, the injection-molded bond (test piece) that the inventor most wanted to obtain was one made of titanium alloy and PEEK resin. This was not successful using triethanolamine, but was successful for the first time using EDTA·4Na. Furthermore, the injection bonding force obtained showed a strong bonding force exceeding approximately 60 MPa. The same thing did not happen when the metal material was changed from a titanium alloy piece to a steel piece. Also, when EDTA or EDTA·2Na were used instead of EDTA·4Na, a strong bonding force could not be obtained. It is presumed that amine compounds with large molecular weights and formula weights have a wide variety of steric properties, and even if physical adsorption occurs, it will vary depending on where the compound is attached to the metal piece. Naturally, simply having a large molecular weight or formula weight does not guarantee good results. In short, the conditions that the inventor states in the SNMT theory are necessary conditions, not sufficient conditions. However, the thought process of figuring out the necessary conditions is of utmost importance. Once the necessary conditions are solidified, you can come up with 10 or even 100 things that fit them. By conducting experiments and tests on these compounds one after another, a person skilled in the art only needs to find at least one that is practical in terms of work, environmental safety, productivity, etc., and the selection of these compounds is easy if explored using the above-mentioned technical concept.

[0032] Furthermore, requirements (e) and (f) of the resin conditions are substantially the same as requirements (3) and (5) under the NMT conditions, and requirements (3) and (4) under the aforementioned new NMT conditions, defining that the same resin composition is effective for NMT, new NMT, and SNMT. However, to be precise, requirement (4) under the NMT conditions means that polyolefin resins, fluorine resins, etc., which have no hydrophilicity at all, cannot be used as resin types. Although not explicitly stated, both new NMT and SNMT require that polyolefin resins not be used as the main component resin in the resin composition. The reason for this is that the majority of the surface of the metal material is hydrophilic, with a thin metal oxide layer such as a native oxide layer formed thereon. On the other hand, all high-strength crystalline thermoplastic resins other than polyolefin resins are hydrophilic and not lipophilic. Hydrophilic materials have a certain degree of chemical affinity for each other, and therefore, in a metal piece that satisfies the requirements (a to c) of SNMT as defined in this invention, the existence of the ultrafine uneven surface portion with a period of several nanometers is very large, and its surface area is estimated to be three or four orders of magnitude or more when the actual surface area is divided by the apparent area, which is very large.

[0033] In short, the concept of injection bonding theory, including the present invention, is that if the surface of a metal piece can be made into a complex, double or triple-layered ultrafine uneven surface, then a resin composition that is an oxide (requirement d) and hydrophilic, which penetrates deep into the ultrafine depressions on the ultrafine uneven surface, crystallizes, and solidifies should exhibit the highest level of bonding strength. In NMT and SNMT, amine molecules adsorbed on the metal surface help to penetrate smoothly into the depths of the ultrafine depressions in a supercooled state, maintaining its liquid phase, without solidifying the resin flow. Specifically, hydrated hydrazine can be used in NMT, and large-mass water-soluble amine substances with expected physical adsorption properties can be used in SNMT. Triethanolamine and EDTA derivatives have been experimentally confirmed to be effective. However, the substances that can be used in the present invention are not limited to these substances; if chemically searched for large-mass amine substances, many other chemical substances can be used.

[0034] [Water-soluble amine compounds used in SNMT and adsorption theory] In this invention, the term "amine compound" refers to a high molecular weight amine compound. In the development process of the SNMT proposed in this invention, the first water-soluble amine molecule used was triethanolamine, while in the NMT developed earlier, the water-soluble amine molecule was hydrated hydrazine. However, in the SNMT of this invention, hydrated hydrazine is not used as the amine molecule. The reason for this is that when an aqueous solution of hydrated hydrazine was used as an immersion solution for chemically etched Al alloys, a reasonable bonding strength was obtained for injection-bonded materials containing PEEK, although the strength was not ideal as intended. However, with respect to non-aluminum metal materials, injection-bonded materials obtained by adsorbing an aqueous solution of hydrated hydrazine did not achieve the target bonding strength at all. In short, it is certain that Al alloys and hydrated hydrazine are chemically adsorbed unusually strongly, but the inventors estimate that it may be more accurate to view this as a chemical reaction rather than chemical adsorption. On the other hand, with respect to non-aluminum metal materials, the chemical adsorption force with hydrated hydrazine is at a typical level, or significantly weaker compared to the situation that occurs with aluminum alloy materials. As a result, when the temperature rises to the mold temperature during injection bonding (140°C for most resin types), the total adsorption force (sum of chemical and physical adsorption forces) decreases, and it is thought that hydrated hydrazine will desorb.

[0035] In short, even non-aluminum metal materials have a surface layer covered with a native oxide layer, most of which is a hydrophilic metal oxide and therefore polar. If the water-soluble amine molecules adhering to this are polar substances such as hydrated hydrazine and triethanolamine, the adsorption force between them will include not only physical adsorption, which occurs as long as there is mass, but also chemical adsorption. However, with non-aluminum metal materials, the chemical adsorption force itself is clearly weaker compared to when using Al alloys, so we have no choice but to rely on physical adsorption. When exposed to high temperatures, the chemical adsorption force may decrease or increase, but the physical adsorption force, which relies on van der Waals forces (intermolecular attractive forces), is only proportional to the molecular mass, and as the temperature rises, the desorption force becomes stronger and the physical adsorption force decreases. Therefore, it is easier to understand these as appearing only in a physical adsorption state. For this reason, hydrated hydrazine, which has weak physical adsorption, cannot be used in SNMT treatment, but triethanolamine could be used. Furthermore, in SNMT (Surface Molding) using PEEK-based resin compositions as the injection resin, where the injection bonding reaction will not proceed unless the mold temperature during injection bonding is kept high at 180-200°C, triethanolamine does not perform its function. However, when using EDTA derivatives with a higher molecular weight, the only applicable metal species in the experiments of this invention was titanium alloy, but the effect was outstanding. Therefore, when high injection bonding strength with PEEK-based resin is required for various steel materials other than titanium alloy, it is advisable to apply SNMT treatment using high molecular weight amino acids.

[0036] [A composite material created by joining dissimilar materials using injection bonding] Based on the experimental results and discussion above, it is possible to firmly bond all practical crystalline thermoplastic resins and non-aluminum metal materials, and therefore, the following three types of bonding technologies can be predicted. (1) One approach is to generalize SNMT as an injection bonding technology using metal pieces and crystalline thermoplastic resins, and to develop it as an injection bonding technology for bonding solid materials other than metals that have high hardness. (2) Another method involves inserting two materials, including metals, as opposing pairs within the injection molding die of an injection molding machine, and then injecting a crystalline thermoplastic resin into the gap between the two materials to produce a unified product of all three. In short, this is a new bonding structure in which the injected crystalline thermoplastic resin functions as a kind of adhesive (see Figures 8 and 9 described later). (3) Another prediction is that if we loosen the SNMT theory slightly and limit the surface roughness to only roughening (matte finish for metals) with a period of 20-50 μm and fine roughness with a period of a few μm, that is, if we omit the condition of ultrafine roughness with a period of 10-100 nm, then the solid material to which the injection resin is applied in injection bonding can be easily obtained even if it is not a metal material. These requirements (1) to (3) are identical to those of the "injection bonding technology that uses solid materials with high hardness in place of metal pieces" mentioned earlier. By relaxing the SNMT conditions of this invention, the scope of injection bonding technology can be expanded to include not only metal materials, but also inorganic materials such as stone, ceramics, and glass, as well as organic materials such as wood, and even plastic molded products. The application of SNMT proposed in this invention can thus open up new technologies and fields in areas such as general merchandise and the restoration of cultural properties such as kintsugi (gold repair).

[0037] [Scope of metal materials as defined in this invention] In this invention, the metal material (non-aluminum material) is selected from steel, titanium alloy, and stainless steel. The reason for this is that the SNMT treatment in this invention determines whether or not the surface shape specified by SNMT can be reproduced. As mentioned above, when the metal material is roughened and an ultrafine surface with the smallest surface irregularity period of 10 to 100 nm is formed, the question is whether SNMT reliably provides high injection bonding strength. That is, if SNMT-treated products of all metal types are inserted into an injection bonding mold, PBT, PPS, and polyamide-based injection bonding resins are injected into them, and the water-soluble amine compound used in the SNMT treatment is triethanolamine, will all metal types used exhibit the highest possible injection bonding strength? Experimental results show that this is not necessarily applicable to all cases. This is true for C1100 copper, and SNMT treatment was not suitable for pure copper-based metal materials. For pure copper-based materials, only products with the new NMT treatment can be used. In short, with PBT and PPS resins, the highest level of injection-molded products can be obtained by using products with the new NMT treatment. However, it is not possible to obtain high-strength injection-molded products with polyamide or PEEK resins. The reason for this is that the final step in the surface roughening treatment of the copper material is immersion in an oxidation accelerator, which creates an ultrafine uneven surface with a period of 10 to 100 nm, generating numerous whiskers and creating an ultrafine uneven surface. This reaction ultimately creates fine copper oxide structures on the surface, and since this is a surface treatment for injection bonding, the entire surface becomes a black surface of cupric oxide.

[0038] This black copper oxide thin layer is quite hard, and if the resin penetrates and solidifies deep into its ultrafine recesses, the composite exhibits high shear bond strength. Therefore, injection-bonded structures of PPS resin and copper are used as complete sealants in the sealing parts of copper electrodes in lithium-ion batteries (LIBs). However, in injection bonding with polyamide resins and PEEK resins, C1100 copper treated only with the new NMT process cannot be used because crystallization begins before the resin can penetrate deep into the ultrafine recesses. Therefore, we attempted to physically adsorb these by immersing the copper pieces in a 0.2% aqueous solution of triethanolamine, but instead of adsorption, the copper pieces, which had already undergone the new NMT process, reacted clearly with the triethanolamine. In short, the triethanolamine reduced the copper oxide thin layer, changing its color from black to pink (cupric oxide was reduced to cuprous oxide). The same thing happened when immersed in an aqueous solution of EDTA·4Na. The amine molecules that were supposed to be adsorbed were digested. Copper is a metal that readily undergoes oxidation and reduction at low temperatures, making it unsuitable for NMT and SNMT theories, and it was one of the few metals that followed the new NMT theory. As can be understood from the above explanation, the metal material referred to in this invention does not include copper.

[0039] Next, let's consider SPCC (cold-rolled steel). When SPCC is injection-bonded to PEEK, PEEK-based resins, etc., the new NMT does not necessarily achieve high bonding strength. Injection bonding of SPCC to the aforementioned polyamide resin "CM3506G50" showed optimal bonding strength with SNMT using triethanolamine. In injection bonding using PEEK-based resins, which are used in a higher temperature range, the Ti alloy showed favorable results with the corresponding EDTA·4Na, while SUS304 steel showed slightly better results. In the inventors' evaluation, not only SPCC but also SUS430 did not yield favorable results. The salt (Na) structure does not necessarily yield favorable results for all metal types. However, even though the inventors have invented and proposed SNMT, the current SNMT only allows for injection bonding strength to approach the maximum value with Al alloys and 64Ti alloys, but this is a sufficient result for those skilled in the field of chemistry. This is because applications requiring PEEK, PAEK, etc., are areas where wear resistance, heat resistance, and corrosion resistance are important, and titanium alloys are considered the most suitable metal for use in these areas. However, it is unclear what metal composites will be required in injection-molded products using PEEK, PAEK, etc. in the future, but as mentioned above, this can be addressed by finding new water-soluble amine compounds that can work with all metal types.

[0040] [Regarding the injection bonding operation and annealing treatment of the present invention] The injection bonding method used in this invention involves creating an injection bonding mold, inserting a surface-treated metal piece into the open mold, closing the mold, and injecting resin. This injection bonding operation is a known technique and not a special one. If anything, the key points are the mold temperature and holding pressure time. The mold temperature can be within the temperature range recommended by the resin manufacturer, but it is generally better to set it higher. Specifically, when using the aforementioned PPS-based resin "SGX120" and polyamide-based resin "CM3506G50", a mold temperature of around 140°C is preferable. For PAEK-based resins, it was set to 180-190°C. Another important point is the pre-injection time and holding pressure time. If the insert is large, for example, weighing 1 kg or more, instead of inserting it and closing the mold, the injection operation should not proceed immediately. Instead, it is necessary to wait for about 30-90 seconds until the temperature of the insert is approximately equal to the mold temperature before injecting the molten resin composition. The reason for this is the same as the reason for setting the mold temperature. Furthermore, regarding the holding pressure time, in the case of "CM3506G50" mentioned above, the crystallization rate during rapid cooling appears to be somewhat slow, so a holding pressure time of approximately 30 seconds was set from the start of injection to the end of holding pressure. Also, the injection temperature when using PEEK-based resin is somewhat high, at 370-380°C. In other words, although the melting point of PEEK resin is said to be around 340°C, in experiments, the fluidity was poor unless the injection temperature was 370°C or higher.

[0041] High-crystalline thermoplastic resins such as PPS, polyamide, and PBT could be smoothly injected and injected bonded even with a sufficiently low melt viscosity, as long as the injection temperature was about 10°C above their melting point. PEEK, however, according to the manufacturer's specifications, seems to require an injection temperature about 30°C above its melting point. As experts suggest, it might be better to consider PEEK as a semi-crystalline resin possessing the physical properties of both amorphous and crystalline resins. Of course, the resulting injection-bonded product is not simply allowed to cool to become the final product. Within a few hours, it undergoes a heat treatment (annealing) at 170-190°C for about an hour to sufficiently promote resin crystallization before completing the entire injection bonding process. In the previous section, it was stated that the injection-bonded product should be obtained with a time of nearly 30 seconds from resin injection to the end of holding pressure, but the annealing treatment is performed on the injection-bonded product after this process.

[0042] [Method for conducting and evaluating a 3,000-cycle thermal shock test] This invention presents a temperature shock test of the integrated metal-resin composite (hereinafter also referred to as "integrated composite" or "injection-molded product") and its manufacturing method. In the composite of the non-aluminum metal material of the present invention and the aforementioned PPS-based resin "SGX120", the target value of the shear bond strength was set to approximately 40-42 MPa, slightly higher by adopting the SNMT treatment method. Furthermore, we succeeded in acquiring full-scale injection bonding technology using the non-aluminum metal material and the aforementioned polyamide-based resin "CM3506G50", and the non-aluminum metal material and PEEK-based resin. Examples of applications for these injection-molded products include automobile parts, and the use of materials for components of all mobile machinery, including aircraft, mobile robots, and drones. In other words, they can be used for housings, parts, etc., of general machinery used indoors and outdoors, and we can provide metal-resin composite materials for this purpose. However, for mobile machinery such as automobiles and aircraft, temperature shock must also be considered, and the product must be able to withstand severe temperature shocks. Regarding automobiles, if they are used in extremely cold environments like Alaska or Siberia, temperatures can drop to -50°C in winter. In scorching desert areas, the exterior of a car can reach +80°C, and in places like Death Valley in the US, the interior of an unoccupied car can reach +100°C due to sunlight. In the case of aircraft, while the stratosphere can reach -50°C, the wings of an aircraft waiting at a tropical airport can reach +100°C. In short, in the case of automobiles, some parts, such as those around the engine compartment or near the main lamps in Alaska or Siberia, require 3,000 cycles of temperature shock testing at 50°C / +150°C, while other parts, such as the body and wing structures of automobiles and aircraft, require 3,000 cycles of temperature shock testing at -50°C / +80°C.

[0043] The injection-molded bond between the aforementioned PPS resin "SGX120" and the aforementioned NMT2-8 treated Al alloy, i.e., the test specimen shown in Figure 1, exhibited a shear bond strength of approximately 40 MPa. Regarding the shape of this injection-molded bond between the PPS resin and Al alloy, guidance is needed on how to structurally design it so that it can withstand a 3,000-cycle temperature shock test at -50°C / +150°C. A structural example for this purpose was conceived and proposed and disclosed by the inventors (Patent Document 5). The composite of the present invention differs from the injection-molded bond between the Al alloy described in Patent Document 5 and the above-mentioned polyamide resin "CM3506G50". The composite of the present invention is an injection-molded bond consisting of an SNMT-treated non-aluminum metal and the above-mentioned PPS-based resin "SGX120", or an SNMT-treated non-aluminum metal and the above-mentioned polyamide-based resin "CM3506G50", or an SNMT-treated non-aluminum metal and a PEEK-based resin. The only difference between these is the material used in the injection-molded bond. In short, the resin structure is exactly the same as that described in Patent Document 5, and these injection-molded bonds can also withstand a 3,000-cycle temperature shock test at -50°C / +150°C. Therefore, the test method described in Patent Document 5 will be described below.

[0044] [Temperature shock test and thickness, composition, etc. of the resin part] First, determine the type of the injection-bonded product. For example, determine the target object such that an injection-bonded product of SNMT-treated SUS304 steel and the above polyamide resin "CM3506G50" is to undergo a temperature cycle test of 3,000 cycles. Then, produce a dozen or so injection-bonded products of the test pieces shown in FIG. 1. Cut several of them, which is one-third of the total, using a router, which is a cutting machine, to obtain the shape shown in FIG. 4, that is, scrape off the upper surface of the bonding surface of the resin part that was 3 mm thick, and make the resin part 2 mm thick. Then, cut several of them, which is also one-third of the original test pieces shown in FIG. 1, using a router to obtain the shape shown in FIG. 5, that is, scrape off the upper surface of the bonding surface of the resin part that was 3 mm thick, and make the resin part 1 mm thick. Through this operation, a dozen or so test pairs to be subjected to the temperature cycle test were prepared. That is, the basic shape is the test piece shown in FIG. 1, but the resin part thickness on the back of the bonding surface was processed into three types: 3 mm thick, 2 mm thick, and 1 mm thick. All of these were subjected to a temperature cycle test of -50°C / +150°C for 3,000 cycles.

[0045] Proceed all at once until after the completion of the 3,000-cycle test. Take them out of the testing machine and leave them standing for about one day, and then break all the test pairs and conduct inspections. First, for the one with a resin part thickness of 3 mm, since this is the one of the test pieces shown in FIG. 1, break it with a tensile testing machine to measure the shear bonding strength, and observe the bonding surface trace on the metal side. As preliminary knowledge, the linear expansion coefficient of this metal part is 0.8×10 -5 K -1 for Ti alloy, 1.1×10 -5 K -1 for general steel plates and ferritic stainless steels, and about 1.6×10 -5 K -1 for austenitic stainless steels. For the resin part bonded to this, in the case of the above "SGX120", it is about 4.0×10 -5 K -1 ; in the case of the above polyamide resin "CM3506G50", it is about 2.5×10 -5 K -1 ; and in the case of a 95:5 mixture of PEEK and PEI, it is about 8.0×10 -5 K -1 approximately. Therefore, for all combinations of the composite of the present invention, on the metal side, it is (0.8~1.6)×10 -5 K-1 The resin side is (2.5~8.0) x 10 -5 K -1 Therefore, the coefficient of linear expansion is always smaller on the metal side than on the resin side. The smallest difference in coefficient of linear expansion among these is found in the composite of the polyamide resin "CM3506G50" and SUS304 steel, which is approximately 0.9 × 10⁻⁶. -5 K -1 Therefore, given this difference in linear expansion coefficient, it is estimated that even if the test specimen shown in Figure 1 with a resin thickness of 3 mm after 3,000 cycles had an initial shear joint strength of approximately 50 MPa, there would be no resin adhesion at the four corners of the metal-side joint surface and at two of the four edges, resulting in a joint strength of less than 30 MPa.

[0046] The inventors conducted a 3,000-cycle temperature shock test at -50°C / +150°C on various injection-molded products of Al alloy and PPS-based resin, and Al alloy and polyamide-based resin, prior to the invention (Patent Document 5). Figure 6 shows the delamination state of the joint surface due to temperature shock. Figure 6 shows an injection-molded product where the metal plate is an Al alloy plate and the injection resin is the above-mentioned PPS-based resin "SGX120". After a 3,000-cycle temperature shock test at -50°C / +150°C, the state of the joint is diagrammed. In the test piece shown in Figure 5, an injection-molded product with a resin thickness of 1 mm at the joint surface showed no delamination at all (see Figure 6(b)). In the test piece shown in Figure 4, an injection-molded product with a resin thickness of 2 mm showed delamination at one or two corners of the joint surface (see Figure 6(d)). The injection-molded bonded products obtained by the present invention (SNMT treatment), i.e., Figures 1, 4, and 5, and their resin thicknesses of 3 mm, 2 mm, and 1 mm, were simultaneously placed in a thermal shock tester in units of several pieces, similar to the 3,000-cycle thermal shock test described above. In this long-term thermal shock cycle test, a small amount of delamination was observed in the 1 mm thick resin portion. In the 3 mm thick resin portion, delamination occurred from the four corners and edges and spread, eventually leaving a circular bonded surface in the center.

[0047] Since this invention does not use an Al alloy as the metal material, the difference in linear expansion coefficients between the metal material and the resin material is considerably larger than that of the injection-molded product made of Al alloy and the polyamide resin "CM3506G0" shown in the previous invention (Patent Document 13). From these test results, it can be estimated that an injection-molded product of this invention that does not delaminate for a long period of time is suitable for a resin part with a thickness of 0.5 to 0.8 mm, with a wall thickness of 1 mm or less, that is bonded to the metal. The results of a 3,000-cycle temperature shock test of these composites show that products with high injection bonding strength are not necessarily strong against temperature shock. On the other hand, it is natural from a materials mechanics perspective that the greater the difference between the linear expansion coefficient of the resin material itself and the linear expansion coefficient of the metal material, the more likely the bonded surface is to delaminate early due to fatigue failure. As a countermeasure, the resin part should be made soft so that it can follow the expansion and contraction of the metal material; if the resin part is hard, delamination will occur early. In other words, from a materials mechanics perspective, if the flexibility of the resin part is high, the expansion and contraction of the resin part that follows the expansion and contraction of the metal material is easy, and it can be said that it is resistant to temperature shock. Furthermore, it can be said that the shear bonding strength of the injection-molded resin was approximately 42 MPa when using the PPS-based resin "SGX120" in the experiment, but approximately 64 MPa when using the polyamide-based resin "CM3506G50".

[0048] The difference between 40 MPa and 64 MPa is related to the GF content in the resin composition. The former has a GF content of 20%, while the latter has 33.3%, a ratio of 1:1.6. The shear bond strength is 42 MPa for the former and 64 MPa for the latter, a ratio of 1:1.5. The two ratios correspond well, and indeed, a higher GF content makes the resin stronger and more durable, increasing the injection bonding strength. However, while a stronger and more durable joint means the material becomes harder in terms of material mechanics, in thermal shock tests, the edges, where thermal deformation is greatest, are more prone to delamination. In other words, if the strength of the injection bonding strength depends on the GF content, then the effect of the resin becoming harder cancels out and is not very useful. Therefore, whether a material is strong or weak in thermal shock tests is mostly influenced by the difference in linear expansion coefficients between the metal and resin materials. In the case of the present invention, where the difference in linear expansion coefficients is clearly large, delamination as shown in Figure 6 will not occur, and a larger change should result. For example, if a Ti alloy with a low coefficient of thermal expansion is used for the metal material, the difference in coefficient of thermal expansion will be large regardless of the resin material used. For this reason, as shown in Figure 5, even with a resin thickness of 1 mm, a 3,000-cycle thermal shock test will cause delamination at the four corners of the joint. Even if the resin thickness is reduced to 0.8 mm, this problem may not be resolved. However, there is no way to confirm this other than to create a 0.8 mm thick resin sample and conduct a practical test.

[0049] In other words, in the composite combination of the present invention, the metal side (titanium material, Ti alloy, general steel, ferritic stainless steel, austenitic stainless steel) is (0.8~1.6) × 10 -5 K -1 The resin side is (2.5~5)×10 -5 K -1Therefore, the difference in linear expansion coefficients between the resin and metal sides is large regardless of the type of resin used. In particular, the difference in linear expansion coefficients becomes large when using Ti alloys, general steel materials, and ferritic stainless steel as the metal material. When a 3,000-cycle temperature shock test was conducted at -50°C / +150°C, even an injection-molded joint with a resin thickness of 1 mm, as shown in Figure 5, showed signs of delamination at all four corners. In this case, as mentioned above, the reason for making and verifying resin thicknesses up to 0.8 mm is that it is common knowledge among injection molding engineers that the limit for mass-producing wide sheet-like materials by injection molding is a wall thickness of about 0.8 mm. It is not impossible to make a sheet-like material with a wall thickness of 0.5 mm using injection molding. However, as an injection bonding mold, there is a possibility that the injection resin temperature at the end of the molten resin flow will be low (and the injection bonding force at the end may be low), which is not practical, and therefore the resin thickness is limited to 0.8 mm.

[0050] Another reason is that, as explained in the thermal shock cycle test above, even when the resin thickness was reduced to 1 mm, the results in the 3,000-cycle test were not good, so it was determined that even if the resin thickness was extended to 0.8 mm, it would not be able to withstand the thermal shock. However, this judgment was based on the premise of a 3,000-cycle thermal shock test at -50°C / +150°C, which may have been too harsh as practical experimental conditions. If the application of this composite is, for example, in an engine room of an automobile, or in a location away from equipment that emits high temperatures such as light bulbs, then there will be no problem. If the natural environment is only harsh, even if it is used in an automobile, it can withstand a thermal shock of -50°C / +80°C for 3,000 hours. In short, depending on the application in which the composite will be used, it is necessary to conduct tests that can withstand the required specifications.

[0051] On the other hand, even if the coefficients of thermal expansion between metal and resin differ significantly, large temperature differences between summer and winter in natural environments do not necessarily mean that cracks or delamination will occur at the joint surface of injection-molded joints (composites) that are held together by bonding forces. In other words, gradual temperature changes do not generate a large load on the joint surface, or the load is low. However, in a thermal shock test, which is an artificial load, the rate of temperature change is fast and repeated, so creep stress does not occur, or is low. In this thermal shock test, we will consider whether or not there is a temperature range in which the internal stress near the joint surface between metal and resin becomes zero. In essence, what is the moment when the internal stress near the joint surface of metal and resin becomes zero, several days after the start of the thermal shock cycle test of several thousand cycles? In terms of the time before the creep test, this would be the room temperature before the start of the thermal shock test, but in the thermal shock cycle test machine used by the inventors, the time that the cage containing the test piece is exposed to and remains at room temperature in either the high-temperature chamber or the low-temperature chamber is 30 minutes.

[0052] When moving between the partitioned high-temperature and low-temperature chambers, the material enters a separate room separated by a partition. Within this separate room, the material is repeatedly subjected to periods of approximately 5 minutes to converge to predetermined high and low temperatures, resulting in a total cycle of approximately 70 minutes for the thermal shock test. After the thermal shock test begins, it is estimated that the core temperature of the temperature change, for example, around +50°C for a -50°C / +150°C thermal shock test and around +15°C for a -50°C / +80°C thermal shock test, is the temperature at which the internal stress of the injected bonded material becomes zero. The deviation from this core temperature is 100°C for the former and 65°C for the latter, meaning the temperature change is 65% of the former's 100%, a reduction of 35%. Under this latter condition (the 35% reduction), it can be estimated that delamination of the bond surface will not occur in all combination injection-bonded materials (composites) of the present invention if the resin thickness is 0.8 to 1.0 mm. In any case, the above experiment involving a 3,000-cycle temperature shock will clearly demonstrate this.

[0053] Based on the above considerations, in any case, if the maximum and minimum temperatures required are appropriately set and a 3,000-cycle thermal shock test is conducted, and there is absolutely no delamination at the joint surface of the 1.0 mm thick injection-molded resin piece shown in Figure 5, then it indicates that an infinitely large joint area of ​​the 1.0 mm thick injection-molded resin piece can withstand that 3,000-cycle thermal shock test. It was determined that it is sufficient if the test piece shown in Figure 5, with a resin thickness of 1.0 mm, can withstand that 3,000-cycle thermal shock test. It was determined that the same durability is obtained when the shape shown in Figures 7, 8, and 9, described later, is adopted for the injection-molded resin (composite). In any shape or lamination, the key is to keep the resin thickness at the joint to approximately 1.0 mm or less. Therefore, when the resin thickness is limited to 0.8 mm, the joint structure will be as shown in Figures 7, 8, and 9. However, if it is determined that the resin thickness must be 0.8 mm or less to withstand the 3,000-cycle thermal shock test, it is best to use it in a range with a reduced temperature range in the thermal shock test. To explore these conditions, it is advisable to test the specimen shown in Figure 5 using a thermal shock test. Other test methods are possible, but they are not relevant to the essence of this invention and will not be mentioned.

[0054] On the other hand, when improving resin materials to withstand temperature shock, if the aforementioned polyamide resin "CM3506G50" is used, there is a method to reduce its GF content from 33.3% by weight to 25% by weight or 11% by weight. If the shear joint strength is measured using the test piece shown in Figure 1, it may decrease from the original 50-65 MPa to values ​​such as 40 MPa or 20 MPa. However, if, for example, a shaped object (laminated) with a resin thickness of 1.0 mm is made as shown in Figure 8, and both ends of this object are cut, and the metal pieces on the left and right are stretched and broken to measure the shear joint strength, even if the above polyamide resin "CM3506G11" with a low GF content is used, a strong shear joint strength of 45 MPa or more can be obtained. If this joint structure is adopted, soft resin materials can be used, not just "CM3506G50". If the shapes shown in Figures 5, 7, 8, and 9 are adopted, it can withstand a 3,000-cycle temperature shock test.

[0055] [Measurement of shear joint strength] ISO 19095 specifies methods for measuring the shear lap-shear strength and tensile strength between metal parts and resin molded parts in injection-molded products. According to this standard, a method is specified in which a test specimen shown in Figure 1 is subjected to tensile fracture using a tensile testing machine to measure the shear strength, and a method is specified in which a test specimen of the shape shown in Figure 2 is subjected to tensile fracture using a tensile testing machine to measure the tensile strength. The shear strength measurement method is the same one used by the inventors in Patent Documents 6 to 10, while the tensile strength measurement method is one that the inventors began using around 2015 after various developments. Neither of these could be measured using the conventional adhesive strength and bonding strength measurement methods specified in JIS K 6849 and JIS K 6850. The applicant (Taisei Plastics Co., Ltd.) proposed a new standard, which was reviewed by Japanese government agencies and then by relevant government agencies in various countries related to ISO, and was approved as ISO 19095. [Effects of the Invention]

[0056] The integrated metal-resin composite of the present invention achieved a strong shear bond of approximately 39 MPa or more between a non-aluminum metal material such as steel, stainless steel, or titanium, and a crystalline thermoplastic resin. teeth, When injection bonding non-aluminum metal materials and crystalline thermoplastic resins, we have identified an optimal compound that can be adsorbed onto the bonding surface of the metal material to increase bonding strength. Furthermore, the integrated composite material of this invention can withstand a 3,000-cycle temperature shock test at -50°C / +150°C. [Brief explanation of the drawing]

[0057] [Figure 1] Figure 1 is an external view of a test specimen used to measure the shear joint strength between the metal and resin parts in an integrated metal-resin composite as specified in ISO 19095. [Figure 2] Figure 2 is an external view of a test specimen used to measure the tensile joint strength between the metal and resin parts in an integrated metal-resin composite as specified in ISO 19095. [Figure 3] Figure 3 is an external view of an auxiliary jig used when measuring the shear joint strength of a metal-resin composite as specified in ISO 19095. [Figure 4] Figure 4 is an external view of the test specimen shown in Figure 1, after a portion of the resin part has been removed and the thickness of the joint has been reduced to 2.0 mm. [Figure 5] Figure 5 shows the external view of the test specimen from Figure 1, with a portion of the resin portion of the joint removed to reduce its thickness to 1.0 mm. [Figure 6] Figure 6 shows the changes in the bond surface of the test specimens shown in Figures 4 and 5, which were created from injection-molded pieces of NMT2-treated A5052Al alloy and PPS-based resin "SGX120," after being subjected to a 3000-cycle temperature shock test at -50°C / +150°C. Figure 6(a) shows a bond thickness of 1.0 mm, and Figure 6(b) shows a bond thickness of 2.0 mm. [Figure 7] Figure 7 shows one example of the shape of the integrated composite according to the present invention, in which a large boss stands on a highly rigid metal plate. Figure 7(a) is a plan view, and Figure 7(b) is a front view. [Figure 8] Figure 8 shows one example of the shape of an integrated composite according to the present invention, which is an example of an integrated composite in which a resin part is bonded and laminated between two metal plates. [Figure 9] Figure 9 shows an example in the integrated composite of Figure 8, where aluminum alloy pins for heat conduction are placed between the metal plates. [Best Mode for Carrying Out the Invention]

[0058] The embodiments of the present invention will be described below with specific injection-molded products (integrated composites of metal and resin). Figure 7 shows one example of the shape of an injection-molded product according to the present invention, which is a basic form with a large boss standing on a highly rigid metal plate. Figure 7(a) is a plan view, and Figure 7(b) is a front view. The injection-molded product 1 consists of a metal rectangular plate 2 made of non-aluminum metal plate with injection channel holes, and a resin molded product body 3 integrally joined thereto. The metal plate 2 is 100 mm in length and width and 3 mm thick. The resin body 3 has a cylindrical part 4 at its center, and four ribs 5 are erected at equal angles along the cylindrical part 4 on its outer surface. The outer circumference of the resin body 3 is supported by a central base 6 that is 2 mm thick and 50 mm rectangular in shape. An outer peripheral base 7 is formed in an annular shape surrounding the outer circumference of this central base 6. The outer peripheral base 7 is formed in a rectangle that is 10 mm wide and 1 mm thick and 70 mm in size. In other words, the injection-molded joint 1, which is made of metal and resin, has a central base 6 and a thinner outer peripheral base 7 formed thereon in order to maintain the bonding force between the resin central parts 4 and 5 and the metal rectangular plate 2. This injection-molded joint 1 was manufactured by fabricating an injection mold, inserting a chemically treated metal rectangular plate 2 into the injection mold, and injecting the aforementioned PPS-based composition "SGX120".

[0059] The metal rectangular plate 2 has undergone the aforementioned SNMT treatment as defined in this invention before insertion. The cylindrical portion 4 on the metal rectangular plate 2 is surrounded on its outer circumference by a thin outer base plate 7 and in its center by a central base plate 6, so that it can absorb differences in thermal expansion. The most important value here is the thickness of the outer base plate, which is 1 mm. This is the result of the 3,000-cycle thermal shock test of the test piece shown in Figure 5, where no peeling occurred with a resin thickness of 1 mm, as shown in Figure 6, and this is the thin outer base plate 7 described above. Therefore, if the results of a pre-tested thermal shock test require a resin thickness of 1 mm or less, the thickness of the outer base plate obtained in Figure 7 should be set to 0.8 to 1.0 mm, while also reducing the temperature difference between the high and low temperatures in the thermal shock test. It is advisable to start by creating a test piece like the one in Figure 5 or a similar object like the one in Figure 5 with a resin thickness of 0.8 mm, and conducting a 3,000-cycle thermal shock test under the new temperature conditions to confirm that it is possible.

[0060] Figure 8 shows an example of a laminate, which is an injection-bonded product according to the present invention. This is an example of two SUS304 steel plates being injection-bonded with a polyamide resin. This laminate is manufactured by inserting two SNMT-treated SUS304 steel plates into an injection molding die with a gap of 1.0 mm between them, and then injecting a polyamide resin into this gap. In this example, the aforementioned "CM3506G50" was used as the polyamide resin. Figure 9 shows an example of two SUS304 steel plates being injection-bonded with a polyamide resin, similar to the laminate in Figure 8. This is an example used for parts and housings where a temperature difference occurs between the two SUS304 steel plates due to heat transfer or radiant heat. This is an example of an injection-bonded product in which two SUS304 steel plates are connected by an Al alloy pin. The heat from the high-temperature SUS304 steel plate is conducted through the Al alloy pins to the lower-temperature SUS304 steel plate, and the heat is averaged out, thus reducing the load caused by thermal expansion at the joint. [Examples]

[0061] The following describes in detail examples of the present invention as experimental examples, and shows the evaluation and measurement methods for the integrated composite (test specimen) obtained from the experimental examples. (a) Measurement of joint strength In this invention, the fracture force obtained when injection-molded joints (Figures 1 and 2) are fractured under tension using a tensile testing machine was used as an indicator of joint strength (shear joint strength, tensile joint strength). However, the auxiliary jig shown in Figure 3 was used for measuring the shear joint strength. The tensile testing machine used was the "AG-500N / 1kN" (manufactured by Shimadzu Corporation (headquarters: Kyoto, Japan)), and measurements were taken at a tensile speed of 10 mm / min. This measurement method conforms to ISO 19095.

[0062] [Experimental Example A] Surface treatment method for metal materials [Experimental Example A1-1] Novel NMT treatment for shot-blasted SPCC (cold-rolled steel sheet) (reference example) Numerous rectangular pieces measuring 18mm x 45mm x 1.6mm thick were machined from commercially available 1.6mm thick SPCC plates. The edges of these SPCC pieces were roughened by shot blasting with white alumina powder ("WA" No. 150). Next, an aqueous solution containing 10.0% aluminum degreasing agent "NA-6" (manufactured by Meltex Co., Ltd. (headquarters: Tokyo, Japan)) was heated to 60°C and the steel pieces were immersed in it for 5 minutes. After that, they were washed with tap water (Ota City, Gunma Prefecture) (hereinafter referred to as tap water). Next, a 5.0% sulfuric acid aqueous solution was prepared in a separate tank at 60°C, and the steel pieces were immersed in it for 4 minutes. After that, they were washed with pure water (hereinafter referred to as washing). Next, a 5% ammonium monohydrogen difluoride aqueous solution was prepared in a separate tank at 65°C, and the steel pieces were immersed in it for 25 minutes. After that, they were washed with water. Next, a 1.0% ammonia solution was prepared in a separate tank, and the steel slab was immersed in it for 1 minute, after which it was rinsed with water. Then, in another tank, an aqueous solution containing 2.0% potassium permanganate, 1.0% acetic acid, and 0.5% sodium hydrated acetate was prepared at 45°C, and the steel slab was immersed in it for 20 minutes, after which it was rinsed with water. Next, it was immersed in a washing tank with an ultrasonic oscillator set up for 7 minutes and rinsed with water. These steel slabs were dried in a hot air dryer at 80°C for 15 minutes, wrapped in aluminum foil, and stored.

[0063] [Experimental Example A1-2] SNMT treatment of shot-blasted SPCC Numerous rectangular pieces measuring 18mm x 45mm x 1.6mm thick were machined from commercially available 1.6mm thick SPCC plates. The edges of these steel pieces were roughened using a shot blasting machine with white alumina powder ("WA" No. 150). Next, an aqueous solution containing 10.0% of the above-mentioned aluminum degreasing agent "NA-6" was heated to 60°C and placed in a water tank equipped with an ultrasonic vibrator. The steel pieces were immersed in this solution for 5 minutes, and then rinsed with tap water. Next, a 5.0% acidic ammonium fluoride aqueous solution was prepared in a separate tank at 65°C. The steel pieces were immersed in this solution for 1 minute, and then rinsed with water. Finally, a 1.0% ammonia solution was prepared in a separate tank. The steel pieces were immersed in this solution for 1 minute, and then rinsed with water. Next, an aqueous solution containing 2.0% potassium permanganate, 1.0% acetic acid, and 0.5% sodium hydrated acetate was prepared in a separate tank at 45°C. The steel piece was immersed in this solution for 5 minutes, and then rinsed with water. Next, it was immersed in a washing tank with an ultrasonic oscillator set up for 7 minutes and rinsed with water. Next, a 1.0% hydrogen peroxide solution was prepared in a separate tank, the steel piece was immersed in it for 0.5 minutes, and then rinsed with water. Next, a 0.2% triethanolamine aqueous solution was prepared at 40°C in a separate tank, the steel piece was immersed for 30 minutes, and then the steel piece was placed in a super-diluted water solution containing 25 PPM of triethanolamine and washed by moving it up and down. After removing it from the super-diluted water tank, a simple draining operation was performed, and it was dried in a hot air dryer at 67°C for 15 minutes. It was then wrapped in aluminum foil and stored.

[0064] [Experimental Example A1-3] SNMT2 treatment of shot-blasted SPCC Numerous rectangular pieces measuring 18mm x 45mm x 1.6mm thick were machined from commercially available 1.6mm thick SPCC plates. The edges of these steel pieces were roughened using a shot blasting machine with white alumina powder ("WA" No. 150). Next, an aqueous solution containing 10.0% of the above-mentioned aluminum degreasing agent "NA-6" was heated to 60°C and placed in a water tank equipped with an ultrasonic vibrator. The steel pieces were immersed in this solution for 5 minutes, and then rinsed with tap water. Next, a 5.0% aqueous solution containing acidic ammonium fluoride was prepared in a separate tank at 65°C and the steel pieces were immersed in it for 1 minute. Finally, a 1.0% ammonia solution was prepared in another tank and the steel pieces were immersed in this solution for 1 minute, and then rinsed with water. Next, an aqueous solution containing 2.0% potassium permanganate, 1.0% acetic acid, and 0.5% sodium hydrated acetate was prepared in a separate tank at 45°C. The steel slab was immersed in this solution for 5 minutes, and then rinsed with water. Next, it was immersed in a washing tank with an ultrasonic oscillator attached for 7 minutes, and then rinsed with water. Next, an aqueous solution of EDTA(4Na) at 40°C and a concentration of 0.4% was prepared in a separate tank. The steel slab was immersed in this solution for 30 minutes, and then washed several times in a prepared 0.1% acetic acid aqueous solution in another tank. After these treatments were completed, the steel slab was dried in a hot air dryer at 67°C for 15 minutes, wrapped in aluminum foil, and stored.

[0065] [Experimental Example A1-4] SNMT2 Processing of SPCC Numerous rectangular pieces measuring 18mm x 45mm x 1.6mm thick were machined from commercially available 1.6mm thick SPCC plates. Next, an aqueous solution containing 10.0% of the above-mentioned aluminum degreasing agent "NA-6" was heated to 60°C and placed in a separate tank. These steel pieces were immersed in this solution for 5 minutes, and then rinsed with tap water. The subsequent liquid treatment was the same as the final part of Experimental Example A1-3, namely, "In a separate tank, an aqueous solution containing 2.0% potassium permanganate, 1.0% acetic acid, and 0.5% sodium hydrated acetate was prepared at 45°C. The steel pieces were immersed in this solution for 20 minutes, and then rinsed with water. Next, they were immersed in a washing tank with an ultrasonic oscillator set up for 7 minutes and then rinsed with water." The treatment thereafter was as follows. Specifically, a 0.4% aqueous solution of EDTA(4Na) was prepared in a separate tank at 40°C, and the steel slab was immersed in it for 30 minutes. Then, it was washed by immersing it several times in a 50 ppm aqueous solution of EDTA(4Na) prepared in another tank. It was dried in a hot air dryer at 67°C for 15 minutes, wrapped in aluminum foil, and stored.

[0066] [Experimental Examples A1-5] SNMT2 Processing of SPCC (Reference Example) Numerous rectangular pieces measuring 18mm x 45mm x 1.6mm thick were machined from commercially available 1.6mm thick SPCC plates. The subsequent liquid treatment was the same as described near the end of Experimental Example A1-3, namely, "Prepare an aqueous solution containing 2.0% potassium permanganate, 1.0% acetic acid, and 0.5% sodium hydrated acetate at 45°C in a separate tank, immerse the steel pieces in it for 20 minutes, and then rinse with water. Next, immerse them in a washing tank with an ultrasonic oscillator set up for 7 minutes and rinse with water." The subsequent treatment was as follows: Prepare an aqueous solution of EDTA(2Na) at 40°C and a concentration of 0.2% in a separate tank, immerse the steel pieces in it for 10 minutes, and then rinse with water. Dry them in a hot air dryer at 67°C for 15 minutes, wrap them in aluminum foil, and store them.

[0067] [Experimental Example A2-1] New NMT treatment for shot-blasted SUS430 steel (reference example) Numerous rectangular pieces measuring 18mm x 45mm x 1.5mm thick were machined from commercially available 1.5mm thick SUS430 steel sheets. The edges of these steel pieces were roughened using a shot blasting machine with white alumina powder (known in the industry as "WA" No. 150). Next, the steel pieces were immersed in a 60°C aqueous solution containing 10% of the above-mentioned aluminum degreasing agent "NA-6" in a water tank equipped with an ultrasonic vibrator for 5 minutes, and then rinsed with tap water. Next, an aqueous solution containing 10% sulfuric acid and 1.0% acidic ammonium fluoride was prepared in a separate tank at 50°C, and the steel pieces were immersed in this solution for 0.5 minutes, and then rinsed with water. Finally, the pieces were immersed in a water rinsing tank equipped with an ultrasonic vibrator for 7 minutes and rinsed with water. Next, an aqueous solution containing 0.5% ammonium acidic fluoride and 5.0% sulfuric acid, heated to 50°C, was prepared in another tank. The steel slab was immersed in this solution for 3 minutes and then rinsed with water. Next, an aqueous solution containing 3.0% nitric acid, heated to 40°C, was prepared in another tank. The steel slab was immersed in this solution for 3 minutes and then rinsed with water. Next, an aqueous solution containing 2.0% potassium permanganate, 1.0% acetic acid, and 0.5% sodium hydrated acetate, heated to 45°C, was prepared in another tank. The steel slab was immersed in this solution for 2 minutes and then rinsed with water. Next, an aqueous solution containing 2.0% potassium permanganate and 3.0% potassium hydroxide, heated to 70°C, was prepared in another tank. The steel slab was immersed in this solution for 15 minutes and then rinsed with water. Next, an aqueous solution containing 1.0% hydrogen peroxide was prepared in another tank. The steel slab was immersed in this solution for 0.5 minutes and then rinsed with water. I dried it in a hot air dryer set to 67°C for 15 minutes, then wrapped it in aluminum foil and stored it.

[0068] [Experimental Example A2-2] SNMT treatment of shot-blasted SUS430 steel Numerous rectangular pieces measuring 18mm x 45mm x 1.5mm thick were machined from commercially available 1.5mm thick SUS430 stainless steel sheets. The edges of these steel pieces were roughened using a shot blasting machine with white alumina powder ("WA" No. 150). The subsequent liquid treatment was similar to the final step described in Experimental Example A2-1, namely, "Next, an aqueous solution containing 2.0% potassium permanganate, 1.0% acetic acid, and 0.5% sodium hydrated acetate was prepared in another tank at 45°C, the steel pieces were immersed in it for 2 minutes, and then rinsed with water." From there, the treatment was as follows: Next, a 1.0% hydrogen peroxide aqueous solution was prepared in another tank, the steel pieces were immersed in it for 0.5 minutes, and then rinsed with water. Next, an aqueous solution containing 0.2% triethanolamine was prepared in a washing tank set to 40°C, and the steel plate pieces were immersed in it for 30 minutes. Then, they were washed with an aqueous solution containing 50 ppm triethanolamine. After these treatments were completed, the pieces were dried in a hot air dryer set to 67°C for 15 minutes, wrapped in aluminum foil, and stored.

[0069] [Experimental Example A2-3] SNMT2 treatment of shot-blasted SUS430 steel Numerous rectangular pieces measuring 18mm x 45mm x 1.5mm thick were machined from commercially available 1.5mm thick SUS430 stainless steel sheets. The edges of these steel pieces were roughened using a shot blasting machine with white alumina powder ("WA" No. 150). The subsequent liquid treatment was the same as the final step described in Experimental Example A2-2, namely, "Next, an aqueous solution containing 2% potassium permanganate at 45°C, 1% acetic acid, and 0.5% sodium hydrated acetate was prepared in another tank, the steel pieces were immersed in it for 2 minutes, and then rinsed with water." The subsequent steps were as follows: Next, a 1.0% hydrogen peroxide aqueous solution was prepared in another tank, the steel pieces were immersed for 0.5 minutes, and then rinsed with water. Next, an aqueous solution containing 0.4% EDTA(4Na) was prepared in a washing tank set to 40°C, and the steel plate pieces were immersed in it for 30 minutes. Then, they were washed with an aqueous solution containing 50 ppm EDTA(4Na). After this washing, the steel plate pieces were dried in a hot air dryer set to 67°C for 15 minutes, wrapped in aluminum foil, and stored.

[0070] [Experimental Example A3-1] Novel NMT treatment for shot-blasted SUS304 stainless steel (reference example) Numerous rectangular pieces measuring 18mm x 45mm x 1.5mm thick were machined from commercially available 1.5mm thick SUS304 stainless steel sheets. The edges of these steel pieces were roughened using a shot blasting machine with white alumina powder ("WA" No. 150). Next, an aqueous solution containing 10% of the above-mentioned aluminum degreasing agent "NA-6" was heated to 60°C and placed in a water tank equipped with an ultrasonic vibrator. The steel pieces were immersed in this solution for 5 minutes and then rinsed with tap water. Then, an aqueous solution containing 1% acidic ammonium fluoride and 10% sulfuric acid was prepared in a separate tank at 65°C. The steel pieces were immersed in this solution for 6 minutes and then rinsed with water. Next, an aqueous solution containing 0.5% acidic ammonium fluoride and 5.0% sulfuric acid was prepared in a separate tank at 50°C. The steel pieces were immersed in this solution for 20 minutes and then rinsed with water. Next, a 3.0% nitric acid aqueous solution was prepared in a separate tank at 40°C, and the steel billet was immersed in it for 3 minutes, after which it was rinsed with water. Then, it was immersed in a washing tank with an ultrasonic oscillator set in place for 7 minutes and rinsed with water. Next, an aqueous solution containing 5.0% sodium chlorite and 10.0% caustic soda was prepared in a separate tank at 55°C, and the steel billet was immersed in it for 6 minutes, after which it was rinsed with water. It was dried in a hot air dryer at 80°C for 15 minutes, wrapped in aluminum foil, and stored.

[0071] [Experimental Example A3-2] SNMT treatment of SUS304 steel Numerous rectangular pieces measuring 18mm x 45mm x 1.5mm thick were machined from commercially available 1.5mm thick SUS304 stainless steel sheets. Next, these steel pieces were immersed in an aqueous solution containing 10% of the aluminum degreasing agent "NA-6" at 60°C in a water tank equipped with an ultrasonic vibrating end for 5 minutes, and then rinsed with tap water. The process thereafter was the same as in Experiment Example A3-1, up to the point where "an aqueous solution containing 5.0% sodium chlorite and 10.0% caustic soda was prepared in a separate tank at 55°C, and the steel pieces were immersed for 6 minutes and then rinsed with water." The subsequent steps were as follows: Next, a 1.0% hydrogen peroxide solution was prepared in a separate tank, and the steel pieces were immersed for 0.5 minutes. Next, a 0.2% aqueous triethanolamine solution was prepared in a separate tank at 40°C, and the steel slab was immersed in it for 30 minutes. Then, in another tank, the steel slab was placed in a superdiluted solution containing 25 PPM of triethanolamine and washed by moving it up and down. After this washing, the slab was removed from the tank, drained, and dried in a hot air dryer at 67°C for 15 minutes. It was then wrapped in aluminum foil and stored.

[0072] [Experimental Example A3-3] SNMT2 treatment of SUS304 steel Numerous rectangular pieces measuring 18mm x 45mm x 1.5mm thick were machined from commercially available 1.5mm thick SUS304 stainless steel sheets. Next, these steel pieces were immersed in an aqueous solution containing 10% of the above-mentioned aluminum degreasing agent "NA-6" at 60°C in a water tank equipped with an ultrasonic vibrator, for 5 minutes, and then rinsed with tap water. The procedure thereafter was the same as in Experiment Example A3-2, up to the point where "an aqueous solution containing 5% sodium chlorite and 10% caustic soda was prepared in a separate tank at 55°C, and the steel pieces were immersed for 6 minutes and then rinsed with water." The procedure continues as follows: Next, a 1.0% hydrogen peroxide solution was prepared in a separate tank, and the steel pieces were immersed for 0.5 minutes. Then, an aqueous solution of EDTA (4Na) was prepared at 40°C and 0.2% concentration was prepared in another tank, and the steel pieces were immersed for 30 minutes. Finally, the steel pieces were placed in an aqueous solution containing 0.1% acetic acid prepared in another tank and washed by moving them up and down. After removing the contents from the tank and draining, the product was dried in a hot air dryer set to 67°C for 15 minutes, then wrapped in aluminum foil for storage.

[0073] [Experimental Example A4-1] Novel NMT treatment for 64Ti alloy (reference example) Numerous rectangular pieces measuring 18mm x 45mm x 1.5mm were machined from 64Ti alloy. An aqueous solution containing 10.0% of the above-mentioned aluminum degreasing agent "NA-6" was prepared in a tank at 60°C, and the alloy pieces were immersed in it for 5 minutes, after which they were rinsed with tap water. Next, an aqueous solution containing 5% acidic ammonium fluoride was prepared in another tank at 65°C, and the alloy pieces were immersed in it for 3 minutes and rinsed with water. Next, an aqueous solution containing 1% acidic ammonium fluoride and 10.0% sulfuric acid was prepared in another tank at 65°C, and the alloy pieces were immersed in it for 6 minutes and rinsed with water. Next, an aqueous solution containing 3% nitric acid was prepared in another tank at 40°C, and the alloy pieces were immersed in it for 3 minutes and rinsed with water. Finally, an aqueous solution containing 2.0% potassium permanganate and 3.0% caustic potash was prepared in another tank at 70°C, and the alloy pieces were immersed in it for 30 minutes and rinsed with water. Next, an aqueous solution containing 5.0% sodium chlorite and 10.0% caustic soda was prepared in a separate tank at 55°C. The steel billet was immersed in this solution for 20 minutes, and then rinsed with water. It was then dried in a hot air dryer set to 80°C for 15 minutes, wrapped in aluminum foil, and stored.

[0074] [Experimental Example A4-2] SNMT of 64Ti alloy Numerous rectangular pieces measuring 18mm x 45mm x 1.5mm were machined from 64Ti alloy. An aqueous solution containing 10.0% of the above-mentioned aluminum degreasing agent "NA-6" was prepared in a tank at 60°C, and the alloy pieces were immersed in it for 5 minutes, after which they were rinsed with tap water. Next, an aqueous solution containing 5.0% acidic ammonium fluoride was prepared in another tank at 65°C, and the alloy pieces were immersed in it for 5 minutes, after which they were rinsed with water. Next, a 3.0% nitric acid aqueous solution was prepared in another tank at 40°C, and the alloy pieces were immersed in it for 3 minutes, after which they were rinsed with water. Next, an aqueous solution containing 2% potassium permanganate and 3% caustic potash was prepared in another tank at 70°C, and the alloy pieces were immersed in it for 30 minutes, after which they were rinsed with water. Next, an aqueous solution containing 5% sodium chlorite and 10% caustic soda was prepared in another tank at 55°C, and the alloy pieces were immersed in it for 10 minutes, after which they were rinsed with water. Next, the steel slab was immersed in a water washing tank with an ultrasonic oscillator attached for 7 minutes and washed. Then, a 0.2% triethanolamine aqueous solution was prepared in another tank at 40°C, and the steel slab was immersed in it for 60 minutes. Next, the steel slab was placed in another tank containing 25 PPM of the prepared triethanolamine solution and washed by moving it up and down. After removing it from the tank and draining it, it was dried in a hot air dryer at 67°C for 15 minutes, wrapped in aluminum foil, and stored.

[0075] [Experimental Example A4-3] SNMT2 treatment of 64Ti alloy Numerous rectangular pieces measuring 18mm x 45mm x 1.5mm were machined from 64Ti alloy. An aqueous solution containing 10% of the above-mentioned aluminum degreasing agent "NA-6" was prepared in a tank at 60°C, and the alloy pieces were immersed in it for 5 minutes, after which they were rinsed with tap water. Next, an aqueous solution containing 5.0% acidic ammonium fluoride was prepared in another tank at 65°C, and the alloy pieces were immersed in it for 5 minutes and then rinsed with water. Next, an aqueous solution containing 3.0% nitric acid was prepared in another tank at 40°C, and the alloy pieces were immersed in it for 3 minutes and then rinsed with water. Next, an aqueous solution containing 2.0% potassium permanganate and 3.0% caustic potash was prepared in another tank at 70°C, and the alloy pieces were immersed in it for 30 minutes and then rinsed with water. Next, an aqueous solution containing 5.0% sodium chlorite and 10.0% caustic soda, heated to 55°C, was prepared in a separate tank. The steel slab was immersed in this solution for 10 minutes, and then rinsed with water. Next, it was immersed in a washing tank with an ultrasonic oscillator set up for 7 minutes and rinsed with water. Then, an aqueous solution of 0.4% EDTA(4Na), heated to 40°C, was prepared in another tank. The steel slab was immersed in this solution for 10 minutes. Finally, the steel slab was placed in a prepared 0.1% acetic acid solution in another tank and washed by moving it up and down. After removing it from the tank and draining, it was dried in a hot air dryer at 67°C for 15 minutes, wrapped in aluminum foil, and stored.

[0076] [Experimental Example A5-1] NMT8 treatment of A6061 Al alloy (reference example) Numerous rectangular pieces measuring 18mm x 45mm x 1.5mm were machined from a 1.5mm thick A6061 Al alloy plate. An aqueous solution containing 10.0% of the above-mentioned aluminum degreasing agent "NA-6" was prepared in a tank at 60°C, and the Al alloy pieces were immersed in it for 5 minutes, after which they were rinsed with tap water. Next, a 10.0% concentration caustic soda aqueous solution was prepared in another tank at 40°C, and the alloy pieces were immersed in it for 1 minute, followed by rinsing with water. Next, an aqueous solution containing 5.0% hydrochloric acid and 1.0% hydrated aluminum chloride was prepared in another tank at 40°C, and the alloy pieces were immersed in it for 1 minute, followed by rinsing with water. Next, an aqueous solution containing 10.0% concentration sulfuric acid and 2.0% concentration acidic ammonium fluoride was prepared in another tank at 40°C, and the alloy pieces were immersed in this solution for 1 minute, followed by rinsing with water. Next, a 1.5% aqueous solution of caustic soda at 40°C was prepared in another tank, and the alloy piece was immersed in it for 2 minutes, then rinsed with water. Next, a 3.0% aqueous solution of nitric acid at 40°C was prepared in another tank, and the alloy piece was immersed in it for 1.5 minutes, then rinsed with water. Next, a 3.5% aqueous solution of hydrated hydrazine at 60°C was prepared in another tank, and the alloy piece was immersed in it for 1 minute. Next, a 0.5% aqueous solution of hydrated hydrazine at 33°C was prepared in another tank, and the alloy piece was immersed in it for 4.5 minutes and then rinsed with water. Next, a 1.0% hydrogen peroxide solution was prepared in another tank, and the alloy piece was immersed in it for 1 minute, then rinsed with water. Next, a 0.2% aqueous solution of triethanolamine was prepared, and the alloy piece was immersed in it for 15 minutes and then rinsed with water. The resulting alloy piece was dried in a hot air dryer set to 67°C for 15 minutes, wrapped in aluminum foil, and stored.

[0077] [Experimental Example A5-2] SNMT treatment of A6061 Al alloy (reference example) The processing method for this Al alloy piece is more than 90% the same as the NMT8 processing method. That is, the parts related to surface shaping are substantially identical. In other words, after creating an 18mm x 45mm x 1.5mm A6061 Al alloy piece, the process from the degreasing step to the final chemical etching step, that is, up to the step of immersing the chemically adsorbed hydrated hydrazine in dilute hydrogen peroxide solution to completely decompose the adsorbed hydrazine molecules, and then washing with water, is exactly the same as other SNMT processes. Therefore, only the steps from there onward will be described. That is, after washing with water, a 0.2% concentration triethanolamine aqueous solution was prepared, the alloy piece was immersed in it for 15 minutes, and then washed with water, but not with pure water, but with a 25ppm concentration triethanolamine aqueous solution. The resulting alloy piece was then dried in a hot air dryer set to 67°C for 15 minutes, wrapped in aluminum foil, and stored.

[0078] [Experimental Example A5-3] SNMT Treatment of A6061 Al Alloy 2 (Reference Example) The processing method for this Al alloy piece is almost the same as the SNMT method, but instead of triethanolamine as the amine compound, an EDTA derivative is used, and it is referred to as the SNMT2 method as described above. Therefore, from the degreasing step to the completion of the final chemical etching step, that is, up to the step of immersing the chemically adsorbed hydrated hydrazine in dilute hydrogen peroxide solution to completely decompose the hydrazine molecules, and then washing with water, it is exactly the same. Hence, only the steps from there onward are described. That is, after washing with water, an EDTA aqueous solution with a concentration of 0.2% at 55°C was prepared, the alloy piece was immersed for 15 minutes, and then washed with water. It was dried in a hot air dryer set to 67°C for 15 minutes, wrapped in aluminum foil, and stored.

[0079] [Experimental Example B] Fabrication of injection-bonded parts and measurement of bonding force [Experimental Example B1] Shear bond strength of injection-bonded products: When using polyamide resin The surface-treated metal pieces obtained in Experimental Examples A1 to A4 were inserted into injection molding dies, and the aforementioned polyamide resin "CM3506G50" was injected for injection bonding to obtain the injection-bonded test specimens shown in Figure 1. The injection temperature was 300°C and the mold temperature was 140°C. The obtained injection-bonded products were annealed by placing them in a hot air dryer at 170°C for 1 hour. The shear joint strength of the obtained test specimens is shown in Table 1. The shear joint strength was measured according to ISO 19095, with the test specimens shown in Figure 1 placed in the auxiliary jig shown in Figure 3 and subjected to a tensile test at 23°C. The results are the average of three specimens.

[0080] [Table 1] Table 1 shows the test results (shear joint strength) of injection-molded products using metal pieces treated with the new NMT type, which was judged to be the best, and SNMT, for SPCC, SUS430, SUS304, and 64Ti alloys. The shear joint strength in the table is the average of three values, and high joint strengths are all higher than the indicated value. However, the new NMT treated product is clearly inferior to the SNMT treated product. Furthermore, as shown in Table 1, SNMT using triethanolamine succeeded in increasing the joint strength for all non-aluminum metals tested here. In addition, EDTA·4Na, which was newly adopted to improve the heat resistance of adsorbents, did not show such simple results. As indicated by the "SNMT2" designation, only the 64Ti alloy produced the best results, and it had no effect on the others, and the results were particularly poor for SPCC.

[0081] [Experimental Example B2] Shear bond strength of injection-molded products: When using PEEK resin As the injection resin, a dry blend of PEEK "90G" (distributed by Victrex Japan Co., Ltd. (Headquarters: Tokyo, Japan)) and PEI "ULTEM9075" (distributed by SHPP Japan (Headquarters: Tokyo, Japan)) in a weight ratio of 95:5 was used. Various metal pieces that underwent SNMT treatment, obtained in Experimental Examples A1-2, A2-2, and A3-2, and various metal pieces that underwent SNMT2 treatment, obtained in A1-3, A2-3, A3-3, and A4-3, were inserted into an injection molding die, and the above-mentioned PEEK-based resin was injected as the injection resin to obtain the injection-bonded test pieces shown in Figure 1. The injection temperature at this time was 360°C, and the mold temperature was 180°C. The obtained injection-bonded products were annealed in a hot air dryer at 170°C for 1 hour. The shear bond strength of the obtained injection-bonded products is shown in Table 2. [Table 2]

[0082] As can be seen from the results in Table 2, the treated product using triethanolamine (SNMT treated product) was completely ineffective when the injection resin was changed to a PEEK-based resin. This was thought to be because, as mentioned above, the mold temperature and resin injection temperature for making injection-bonded products using polyamide-based resins were more than 40°C higher, and the adsorbed substance, triethanolamine, was desorbed at this high temperature. Therefore, we tried heavier EDTA and EDTA derivatives, but although we tried to adsorb EDTA(4H), which is almost insoluble in water, at a liquid temperature of 70°C, we were unable to increase the injection bonding strength, and EDTA(2Na), although soluble in water, also did not yield results. Therefore, we used EDTA(3Na), which is a complete salt but has sufficient water solubility, resulting in "SNMT2". The result was that only 64Ti showed an exceptionally high effect, giving a maximum shear bonding strength of 64 MPa. The results obtained with SNMT2, as shown in Table 2, were quite unusual. While all materials except 64Ti performed poorly, SUS304 managed to achieve a value of 20 MPa. Ferritic stainless steels and general steel materials like SPCC showed surprisingly poor results. We suspect that the cause of these unusual results lies in the stereochemistry of the amine compound used, namely EDTA·4Na salt, but we did not conduct a full theoretical explanation to that extent.

[0083] However, as mentioned earlier, when using the polyamide resin "CM3506G50" as the injection resin, non-aluminum metals excluding copper, in addition to Al alloys, showed high injection bonding properties. Therefore, this invention establishes a high-performance injection bonding technology between metals and resins involving all-crystalline thermoplastic resins other than PEEK and PAEK resins. Furthermore, it has become clear that all-Al alloys and 64Ti alloys are metal alloys that can exhibit shear bonding strengths of 50-65 MPa in injection bonding technology using PEEK and PAEK resins, which are ultra-heat-resistant resins. In other words, in the creation of composites made of metals and resins for parts and components of mobile machinery, mainly automobiles, the combinations of (general steel, stainless steel, Ti alloy, Al alloy) × (polyamide resin) and (Ti alloy) × (PEEK, PAEK resin) will satisfy the highest specifications required for composites at present.

[0084] [Experimental Example B3] Shear bond strength of injection-bonded products: When using PPS resin This embodiment discloses not only successful and unsuccessful examples of injection-molded products between non-aluminum metal materials and polyamide resins and PEEK·PEI mixed resins, as shown in Tables 1 and 2. We also want to demonstrate the usefulness of a newly developed injection-molded bonding method called "Novel NMT." The shear bond strength of the injection-molded product (shown in Figure 1) of the latest Novel NMT-treated non-aluminum metal material and the above-mentioned PPS resin "SGX120" is approximately 40 MPa, which has already reached the highest strength achieved for injection-molded products using "SGX120." However, in order to confirm that the "SNMT" disclosed here is always a superior technology to Novel NMT, we also disclose the test results for injection-molded products using PPS resin.

[0085] Various metal pieces that underwent SNMT treatment, as obtained in experimental examples A1-2, A2-2, A3-2, and A4-2, were inserted into injection molding dies, and the above-mentioned PPS-based resin "SGX120" was injected as the injection resin to obtain the injection-bonded test specimens shown in Figure 1. The injection temperature was 300°C and the mold temperature was 140°C. The obtained injection-bonded products were annealed for 1 hour in a hot air dryer at 170°C. The shear joint strength of the obtained injection-bonded products is shown in Table 3. The measurement method followed ISO 19095, and the injection-bonded test specimens shown in Figure 1 were placed in the auxiliary jig shown in Figure 3 and subjected to a tensile test at 23°C. The results are the average of three samples. [Table 3]

[0086] As is clear from Table 3, the shear joint strength values ​​of the integrated test pieces shown in Figure 1, obtained by injection bonding non-aluminum metal pieces surface-treated with SNMT treatment to the above-mentioned PPS-based resin "SGX120," were all 41-42 MPa, which is sufficiently high. In short, it showed that 41-42 MPa is the upper limit of shear joint strength for injection-bonded products using "SGX120." The inventors had set a value of 200°C or higher as the melting point of heat-resistant crystalline resins. In that sense, among the thermoplastic resins used in the manufacture of various machines, the group of resins with a melting point of 200°C or higher includes PPS at around 290°C, PA66 at around 210°C, and PEEK at around 340°C, and these are the specific resin material types used. In short, the "SNMT" used in this invention is currently sufficiently effective for non-aluminum metals, specifically PPS-based resins and PA66-based resins. Essentially, "SNMT" can be used as an injection bonding technology for all metal types and crystalline thermoplastic resins with a melting point of 200°C or higher.

Claims

1. In a metal-resin composite formed by joining a metal material having a surface-treated surface and the surface to a crystalline thermoplastic resin composition by injection molding, The aforementioned metal material is one selected from steel, titanium alloy, and stainless steel, and its surface is chemically treated. The surface after the chemical treatment has a fine surface with a period of 20 to 50 μm as observed by a 1000x electron microscope, a fine surface with a period of 0.8 to 5 μm as observed by a 10,000x electron microscope, and an ultrafine surface with a period of 10 to 100 nm as observed by a 100,000x electron microscope. The crystalline thermoplastic resin composition has heat resistance with a melting point of 200°C or higher. The crystalline thermoplastic resin composition is integrated by the injection molding operation while a water-soluble high molecular weight amine compound is adsorbed onto the aforementioned surface. The crystalline thermoplastic resin composition has a resin composition containing 70% by weight or more of polyphenylene sulfide, 30% by weight or less of modified polyolefin resin, and 5% by weight or less of a third component resin, and also contains 15 to 25% by weight of glass short fibers. The shear joint strength is 39 to 43 MPa. A composite material of metal and resin characterized by the following:

2. In a metal-resin composite formed by joining a metal material having a surface-treated surface and the surface to a crystalline thermoplastic resin composition by injection molding, The aforementioned metal material is one selected from steel and stainless steel, and its surface is chemically treated. The surface after the chemical treatment has a fine surface with a period of 20 to 50 μm as observed by a 1000x electron microscope, a fine surface with a period of 0.8 to 5 μm as observed by a 10,000x electron microscope, and an ultrafine surface with a period of 10 to 100 nm as observed by a 100,000x electron microscope. The crystalline thermoplastic resin composition has heat resistance with a melting point of 200°C or higher. The crystalline thermoplastic resin composition is integrated by the injection molding operation while a water-soluble high molecular weight amine compound is adsorbed onto the aforementioned surface. The crystalline thermoplastic resin composition is a resin composition containing 10% by weight or more of semi-aromatic polyamide and 90% by weight or less of aliphatic polyamide in the resin content, and glass short fibers accounting for 25% by weight or more of the total composition. The shear joint strength is 45 to 65 MPa. A composite material of metal and resin characterized by the following:

3. In the integrated metal-resin composite according to claim 1 or 2, The aforementioned high molecular weight amine compound is triethanolamine or an EDTA derivative. A composite material of metal and resin characterized by the following:

4. In the integrated metal-resin composite according to claim 1 or 2, The aforementioned steel material is general steel, and the aforementioned stainless steel is a special steel including austenitic stainless steel and ferritic stainless steel. A composite material of metal and resin characterized by the following:

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