JP5166978B2 - Method for producing composite of metal alloy and resin - Google Patents

Description

  The present invention relates to a method for producing a composite of a metal alloy and a resin. More specifically, the present invention relates to a method of manufacturing a composite of a metal alloy and a resin used in a mobile machine, an electric device, a medical device, a general machine, and other manufacturing fields. More specifically, the present invention relates to an injection joining method for simultaneously performing resin molding using an injection molding machine and joining the resin to a metal alloy.

  Technology for integrating metal and resin is required in all manufacturing industries such as automobiles, home appliances, and industrial equipment, and many adhesives have been developed for this purpose. Among these are very good adhesives. For example, an adhesive exhibiting a function at room temperature or by heating is used for joining to integrate a metal and a synthetic resin, and this method is now a common bonding technique. On the other hand, bonding methods that do not use an adhesive have also been studied. There is a method of integrating a high-strength thermoplastic engineering resin without using an adhesive with magnesium, aluminum, light metals that are alloys thereof, and iron alloys such as stainless steel.

  An example is a method of performing resin molding by injecting a resin into a mold and simultaneously bonding the resin and a metal installed in the mold (hereinafter referred to as “injection bonding”). Specifically, a manufacturing technique for injection-bonding polybutylene terephthalate resin (hereinafter referred to as “PBT”) or polyphenylene sulfide resin (hereinafter referred to as “PPS”), which is a thermoplastic resin, to an aluminum alloy has been developed. (For example, see Patent Documents 1 and 2). In addition, magnesium alloys, copper alloys, titanium alloys, stainless steel, general steel materials, etc. have been demonstrated to be capable of injection-bonding the same series of resins and aromatic polyamide resin compositions ( (See Patent Documents 3, 4, 5, 6, 7, and 8).

  The technique relating to the injection joining has been completed by the present inventors. The inventors of the present invention have different technical principles regarding injection joining between the case of aluminum alloy and the case of all metal species, so the former is “NMT” (short for Nano molding technology) and the latter is “new NMT”. ". “NMT” is applicable only to aluminum alloys, but has been put into practical use by the present inventors and has already been put into practical use at home and abroad. In light of the fact that there were many requests for injection bonding of lighter magnesium alloys in the process of commercialization and development of “NMT”, we also examined injection bonding of hard resin using magnesium alloys. As a result, we succeeded in injection joining to magnesium alloys.

  In the process, the hypothesis devised by the present inventor was the “new NMT” theoretical hypothesis. This hypothesis was not limited to metal species, so I thought that magnesium alloy injection joining would be valid for all metal species (generally all materials). After that, we succeeded in injection joining for copper alloy, titanium alloy, stainless steel, and general steel materials, so we believe this hypothesis is almost correct. The theory of “New NMT” is that the bonding is obtained by completely physical factors, and is very simple and clear. This will be briefly described below.

  In the “new NMT” injection joining theory, at least the following conditions are required. First, as a resin composition to be used, it is to use a hard highly crystalline resin, that is, to use PPS, PBT, or polyamide resin. Moreover, it is necessary to make these compositions improved for injection joining. How to improve the resin composition containing PPS, PBT, or polyamide resin will be described later. On the other hand, it is a condition on the metal alloy part side to be inserted into the injection mold, but the surface layer is required to be strong and hard and to have a specific surface shape.

  The conditions on the metal alloy side will be described in detail. It is necessary to perform a chemical treatment corresponding to the metal alloy type to obtain a surface having the following conditions (1) to (3). (1) The metal alloy surface should be an uneven surface with a period of 1 to 10 μm and a height difference of up to about half of the period. That is, the surface must have a roughness on the order of microns. (2) It is necessary that ultra fine irregularities having a period of 10 to 500 nm, most preferably 50 to 100 nm are formed in the irregular surface. (3) The surface should be covered with a thin layer of a ceramic hard phase. Specifically, it should be covered with a thin layer of environmentally stable metal oxides (including metal phosphorous oxides).

  The numerical range under the above conditions is generally common to most metal alloy types, but may be slightly different depending on the metal alloy type and injection joining method. Therefore, it is not necessarily limited to the above numerical range. Also in the present invention, in the first masking injection joining method shown below, the metal alloy surface has (1) an average length (RSm) of contour curve elements of 0.5 to 10 μm and a maximum height roughness ( Rz) has a roughness on the micron order of 0.1 to 5 μm, and (2) is an ultrafine concavo-convex shape consisting of concavo-convex having a period of 5 nm to 300 nm. On the other hand, in the second masking injection joining method shown below, the metal alloy surface has (1) an average length (RSm) of contour curve elements of 0.5 to 10 μm and a maximum height roughness (Rz). It is necessary to have a micron-order roughness of 0.1 to 5 μm, and (2) an ultrafine concavo-convex shape consisting of concavo-convex having a period of 5 nm to 300 nm.

  The unevenness forming the micron-order roughness (referred to as “micron-order unevenness”) can be automatically measured using, for example, a scanning probe microscope. The micron order unevenness is a surface profile curve, and can be displayed as a roughness profile as one of the curves. This roughness curve is defined by the mean length of profile elements (RSm) and the maximum height of roughness profile (Rz). These are numerical values specified by Japanese Industrial Standards (JIS B0601: 2001). This Japanese Industrial Standard (JIS B0601: 2001) was created by translating “ISO 4287” issued in 1997 into Japanese without changing the technical content and the format of the standard slip.

  Before describing the details of the necessary conditions on the resin side, the process of injection joining of a thermoplastic resin will be described by the “new NMT” theory. This explanation will clarify the conditions required on the resin side. Consider a scene in which a metal alloy is inserted in advance into an injection mold and a thermoplastic resin composition is injected into the metal alloy. The injected molten resin composition rushes into an injection mold and is rapidly cooled by a flow path such as a sprue or a gate or a template. Usually, in injection molding, the mold temperature for injection molding is set to a temperature lower by about 150 ° C. than the melting point temperature of the injection resin, so that the resin injected into the injection mold is rapidly cooled. That is, cold water having a temperature of about 0 to + 10 ° C. is poured into an injection mold having a temperature of −150 ° C. Even if the injection pressure is around 1000 atm, it is expected that it is difficult to intrude into the unevenness on the surface of the metal alloy (the unevenness and the ultrafine unevenness forming a micron order roughness).

  For example, water crystallizes immediately and the liquid viscosity rapidly rises, and then freezes and solidifies. However, even when water is rapidly cooled, crystallization or solidification does not occur in zero hours when the temperature becomes lower than the melting point (freezing temperature or freezing point at the pressure in water). That is, the melting point and the freezing point are only equilibrium points that do not include time elements. Although it is said that the liquid is in a supercooled state while being at a temperature below the melting point, even when the liquid is transferred to the extremely low temperature region as described above, there is a short supercooled state.

  The same applies to the resin, and even if it is cooled to a temperature below the melting point, a supercooled state exists for a very short time. Therefore, the metal alloy is inserted in advance in an injection mold, a thermoplastic resin composition is injected into the mold, and the resin composition remains on the surface of the metal alloy within a time during which the resin composition can be kept in a supercooled state. It was anticipated that if the molten resin could penetrate into the irregularities, a special phenomenon that would increase the bonding force by the anchor effect could occur.

  Suppose that (1) the resin has penetrated to the bottom of the recess having a roughness on the order of microns. Furthermore, it is assumed that (2) the resin has penetrated into the concave portion formed by the ultra-fine irregularities to some extent. If the crystallization of the resin progresses after the penetration and complete solidification, the resin that has penetrated and solidified into the concave portion having a micron-order roughness is caught by the ultra-fine irregularities, and the resin in the ultra-fine irregularities becomes It is thought to play a role like a spike and enhance the anchor effect. Moreover, when the surface of the metal alloy is covered with a thin metal oxide layer, the surface of the ultra-fine irregularities is extremely hard, so the resin spike becomes stronger and the roughness on the micron order is reduced. It is presumed that it is difficult for the resin to escape from the recess formed.

  In addition, it is considered that a hard, highly crystalline resin cannot be easily deformed in a recess that has once entered. Therefore, when the resin part is to be peeled off from the metal alloy, it is considered that the strongest force acts and breaks the resin part near the entrance of the concave part having a micron order roughness. It is estimated that it is difficult to peel the resin part from the metal alloy. From the above, the necessary condition on the resin side to obtain a stronger bonding force is to use a hard, highly crystalline resin, and a resin composition with a crystallization rate during quenching significantly slower than usual. It will be suitable.

  In the practical application experiment of the “NMT” theory conducted by the present inventors, a simple resin composition in which a filler such as glass fiber was included in PBT, PPS or the like was initially used. An effort was made to improve injection joint strength by improving As a result, a resin composition suitable for injection joining based on PBT, PPS, or polyamide resin was discovered. That is, in the injection joining using the “NMT” theory, the improvement of the resin composition can be said to be the discovery of a resin composition that has reduced the crystallization speed during rapid cooling, and the present inventors have discovered this. . And the resin composition which reduced the crystallization speed at the time of rapid cooling could be used also by the injection joining by the "new NMT" theory. That is, this resin composition was able to penetrate to the bottom of the concave portion having a micron order roughness on the surface of various metal alloys.

  Here, the PPS resin composition suitable for the “new NMT” includes a polyolefin resin in addition to PPS. Actually, the most effective is a polyolefin-based resin having a polar group, and more specifically, a compound obtained by compounding a small amount of another kind of polymer as the third component as a compatibilizing agent or a compatibilizing aid. This resin compound has a uniform resin fine structure (may be a sea-island structure at room temperature), and is not a sea-island structure containing droplets or the like in a molten state above the melting point, but at a molecular level. A microstructure in which PPS and polyolefin polymer are mixed is desirable.

  When the PPS resin mixed at the molecular level is cooled below the melting point, PPS tries to crystallize, but if there is a different polymer next to it, the crystallization is inhibited and the different polymer is in thermal motion. The crystallization does not proceed until it is moved by. Therefore, there is a possibility that the crystallization rate during the rapid cooling can be slowed down. In fact, there is a fact that any of the PBT, PPS, and polyamide resin-based resin compositions that are suitable for the above-described injection bonding strongly injection-bonds to various metal alloys that have been surface-treated in accordance with “New NMT”. On the other hand, a simple composition crystalline resin containing only a filler does not perform injection bonding, or is a very weak bonding even by injection bonding, and similarly does not perform injection bonding with a resin composition mainly composed of an amorphous resin, Considering that the resin composition could be easily broken even though it seemed to be joined, the selection of the resin composition based on the crystallization rate was correct from the result.

  The present inventors have put "NMT" and "New NMT" into practical use, but there has been a request for decoration mainly from the electronics industry. One is an electronic / electrical device having an aluminum alloy as an outer case, and in particular, there is a request to commercialize the outer portion by anodizing. Specifically, there is a problem when an aluminum alloy part is subjected to a surface treatment based on “NMT” and a PPS-based resin or the like is injection-bonded to obtain an integrated product, which is then anodized. . When an alkali etching or chemical polishing, which is a pretreatment, is performed, as in the case of normal anodizing of individual aluminum parts, the aluminum alloy at the boundary of the joint melts away, creating a recess (pocket that creates a gap in the lower surface of the resin part. Shaped concavity) and the joint surface is eroded.

  Originally, the PPS resin and aluminum alloy injection joint integrated product based on “NMT” is set on the resin side so that anodizing treatment can be performed (Patent Document 9), but it is strong enough to obtain a normal anodized product. It cannot withstand alkaline etching and intense chemical polishing. The inventors of the present invention can greatly avoid the erosion of the joint surface by greatly relaxing the conditions during alkaline etching and switching to a neutralization treatment in which a short time immersion is performed in a nitric acid solution having a concentration of several percent instead of chemical polishing. However, in terms of practical use, the above measures were taken for reasons such as the fact that chemical polishing would eliminate the appearance and the number of tanks in the alumite plant was not sufficient, and the neutralization tank could not be installed. In many cases, it cannot be taken. Even if it has a strong bonding force immediately after injection bonding, it is natural that the bonding force decreases as the melting of the metal alloy proceeds, and when the reduced bonding force is calculated to be sufficient in practical terms Even so, if moisture or salt enters the pocket part over time, destruction will occur earlier than planned.

  In addition, it is an example of “New NMT” using a press-formed product of stainless steel thin plate material, but when the SUS304BA material of mirror surface is treated with “New NMT” type liquid, naturally the surface becomes a rough surface of micron order and mirror surface. Is not. As an example of a mobile electronic device, an external appearance case is made of the above stainless steel material, and bosses and ribs are injection-bonded to the inside. Initially it was talked about painting the exterior part, but at the request of the designer, it was changed to make the exterior part a mirror surface or something close to a mirror surface. Therefore, the appearance of the case parts obtained by injection joining was buffed and re-polished. Since SUS304BA is originally a mirror surface material, it can be understood that the designer of the user maker has changed his mind, but buffing is difficult because stainless steel has high hardness. It was sought to find a reasonable way to avoid liquid treatment of the appearance.

  An example similar to the trouble in anodizing the aluminum alloy injection joint is when re-forming the magnesium alloy injection joint, or when re-forming the general steel injection joint. Also occurs. In addition, as in the case of the stainless steel injection-joined product, the desire to keep the metal side as it was before the “new NMT” liquid treatment was true was also a copper alloy and a titanium alloy. The purpose of the present inventors was to develop a basic technique called injection joining, but for its commercialization, it was also necessary to develop an economical and rational manufacturing method that also considered the subsequent processes.

An object of the present invention is to provide a method for producing a composite of a metal alloy and a resin, which has a strong joining force by injection joining a metal alloy material and a resin.
Another object of the present invention is that even when a composite metal alloy material is subjected to a surface treatment, the surface treatment does not enter the joint surface, and the joint surface can be maintained as it was during injection joining. It is in providing the manufacturing method of a composite_body | complex.
Still another object of the present invention is that when a metal alloy and a resin are injection-bonded to produce a composite having a strong bonding force, the surface of the exposed metal alloy of the composite is subjected to some surface treatment. In such a case, it is an object of the present invention to provide a method for producing a composite of a metal alloy and a resin, which can prevent the surface treatment portion from being broken by masking the surface treatment portion.

JP 2004-216425 A WO2004-055248 JP 2001-225352 A PCT / JP2007 / 073526 PCT / JP2007 / 070205 PCT / JP2007 / 0774749 PCT / JP2007 / 075287 Japanese Patent Application No. 2007-185547 Japanese Patent Application No. 2008-108473

The present invention takes the following means in order to achieve the object.
The method for producing the composite of the metal alloy and the resin of the present invention 1
A shaping step of shaping the metal alloy material into a predetermined shape;
The metal alloy shaped product obtained by the shaping step is inserted into a first injection mold, and a polyolefin resin is injected into a predetermined region of the metal alloy shaped product. A first injection joining step to obtain a covered first composite;
By performing chemical etching on the first composite, the surface of the metal alloy portion of the first composite is (1) the average length (RSm) of the contour curve elements is 0.5 to 10 μm and the maximum It has a roughness on the order of microns with a height roughness (Rz) of 0.1 to 5 μm, (2) and has an ultrafine concavo-convex shape consisting of concavo-convex with a period of 5 nm to 300 nm, (3) and a metal oxide A surface treatment step that is covered with a thin layer of
The first composite that has undergone the surface treatment step is inserted into a second injection mold, and a resin composition containing polyphenylene sulfide resin as a main resin component with respect to the first composite, Resin composition comprising a butylene terephthalate resin as a main resin component, a resin composition comprising an aromatic polyamide resin as a main component, and a different type of aromatic polyamide resin or aliphatic polyamide resin as a subcomponent, and the fat One or more of the resin compositions selected from the group consisting of a group polyamide resin as a main component and a different type of aliphatic polyamide resin or aromatic polyamide resin as a subsidiary component. A second injection joining step of obtaining a second composite in which the resin composition and the first composite are joined;
And removing the polyolefin resin from the second composite to obtain a third composite in which the predetermined region is maintained in a state before the surface treatment process.

The method for producing a composite of a metal alloy and a resin according to the present invention 2,
A shaping step of shaping the metal alloy material into a predetermined shape;
By performing chemical etching on the metal alloy shape obtained by the shaping step, the surface of the metal alloy shape is (1) the average length (RSm) of the contour curve elements is 1 to 10 μm and the maximum It has a roughness on the order of microns with a height roughness (Rz) of 0.2 to 5 μm, (2) has an ultra-fine uneven shape consisting of unevenness with a period of 5 nm to 500 nm, (3) and a metal oxide A surface treatment step that is covered with a thin layer of
The metal alloy shaped article that has undergone the surface treatment step is inserted into a first mold for two-color molding, and a resin composition containing polyphenylene sulfide resin as a main resin component in the first mold, polybutylene terephthalate resin The main resin component, an aromatic polyamide resin as a main component, and a different aromatic polyamide resin or aliphatic polyamide resin as a subcomponent, and an aliphatic polyamide resin as a main component And at least one resin composition selected from a different aliphatic polyamide resin or a resin composition comprising an aromatic polyamide resin as a subsidiary component, and the injected resin composition and the metal alloy A first injection joining step of obtaining a first composite joined with a shaped object;
The first composite is inserted into a second mold, a polyolefin resin is injected into the second mold, and a second composite in which the polyolefin resin and the first composite are joined is formed. Obtaining a second injection joining step;
A surface processing step of applying a predetermined surface processing to the second composite;
By removing the polyolefin resin from the second composite that has undergone the surface processing step, the third composite in which the range in which the polyolefin resin has been bonded is maintained in the state before the surface processing step. And a removal step for obtaining a body.

A method for producing a composite of a metal alloy and a resin according to the present invention 3 is the method for producing a composite of a metal alloy and a resin according to the present invention 1, wherein the metal alloy material is made of stainless steel, titanium alloy, and copper alloy. It is one type selected.
The method for producing a composite of a metal alloy and a resin according to the present invention 4 is the method for producing a composite of a metal alloy and a resin according to the present invention 2, wherein the metal alloy material is an aluminum alloy, a magnesium alloy, a copper alloy, and It is one type selected from general steel materials.
A method for producing a composite of a metal alloy and a resin according to a fifth aspect of the present invention is the method for producing a composite of a metal alloy and a resin according to the second aspect, wherein the first composite formed by the first mold is used. The movable mold plate is used as the movable mold plate of the second mold while maintaining the state of being inserted into the movable mold plate of the first mold.

[Operation of the present invention]
The method for producing a composite of a metal alloy and a resin according to the present invention is based on the “NMT” theory or the “new NMT” theory, and the surface of the metal alloy has a roughness on the micron order, and has an ultrafine uneven shape. In addition, a composite in which the metal alloy and the resin are strongly bonded by performing surface treatment so as to be covered with a thin layer of metal oxide and injection-bonding PBT, PPS, or polyamide resin. You can get a body. Here, due to the surface treatment, the surface texture of the metal alloy surface originally changed, and the mirror surface disappears when it is initially mirror-finished, for example. That is, in the case of an electrical device or the like, the function is impaired by the surface treatment even though the purpose is to give an impression to the user by such mirror finishing or the like. Mirror surfaces and stainless steel plate materials close to the mirror surfaces, titanium alloy materials, copper alloy materials and the like are often used as external cases for electric devices and the like, and can meet strong demands for maintaining the appearance of the surface.

  According to the method for producing a composite of a metal alloy and a resin of the present invention, prior to performing the surface treatment, a predetermined region on the surface of the metal alloy, that is, a range visible from the outside, is masked with a polyolefin resin or the like, After obtaining the composite of the resin for injection joining and the metal alloy, by removing the polyolefin-based resin, it is possible to obtain a composite in which the predetermined region is maintained as it is. That is, the state of the mirror surface of the surface can be maintained without impairing the external appearance of the electric device or the like. On the other hand, with regard to metal species such as aluminum alloys, magnesium alloys, and general steel materials, after obtaining composites of these metal alloys and resins, the composites are anodized to improve decoration and weather resistance. Chemical treatment may be applied.

  That is, chemical treatment is performed after injection joining with PBT, PPS, or polyamide resins, and the chemical treatment may adversely affect the joint surface. According to the present invention, the joint portion between the injection joining resin and the metal alloy in the composite is masked with the polyolefin resin, and after performing a predetermined chemical treatment in that state, the polyolefin resin is removed. This prevents the joint portion from being adversely affected by the chemical treatment. Thus, the present invention is useful in electronic / electrical devices where emphasis is placed on decoration. Hereafter, each process for obtaining the metal alloy and resin composition which are the object of this invention, and those composites is demonstrated in detail.

[Metal alloy parts]
The metal alloy part used in the present invention, that is, the metal alloy used in the above-mentioned “new NAT” is theoretically not particularly limited in the type of metal of the material. The target of injection joining may be all metal species, but what is actually meaningful is a hard and practical metal species and alloy species. That is, since mercury is liquid at room temperature, it cannot be used in the present invention, but soft metal species such as lead are also excluded. Also excluded are alkali metal species and alkaline earth metal species (except magnesium) that react actively in the atmosphere.

  The present inventors have listed alloy types mainly composed of magnesium, aluminum, copper, titanium, and iron as metal alloy types to which “new NMT” can be substantially applied. Hereinafter, six types of aluminum, magnesium, copper, titanium, stainless steel, and general steel materials including aluminum alloys to which “NMT” can be applied will be described. However, the “new NMT” theory does not limit the metal species, and moreover, it does not limit the metal itself. In short, the “new NMT” defines only the surface shape and the hardness of the surface thin layer, and discusses the adhesion by physical anchor effect theory, and is therefore not limited to at least the alloy type of the metal. However, since it is not easy to process a non-metallic surface so as to satisfy the three conditions of “new NMT”, the non-metallic surface is not substantially targeted.

  Regarding the treatment of the metal alloy surface, Patent Documents 1 and 2 described aluminum alloys. Patent Document 4 describes a magnesium alloy. Patent Document 5 describes a copper alloy. Patent Document 6 describes a titanium alloy. Patent Document 7 describes stainless steel. Further, Patent Document 8 describes general steel materials. With respect to the surface treatment of these metal alloy types, individual detailed explanations are omitted. The contents of the surface treatment described in each patent document are exactly the same in the present invention.

[Chemical etching of metal alloy materials]
There are known types of corrosion such as general corrosion, pitting corrosion, fatigue corrosion, etc., but it is possible to select an appropriate etching agent by selecting a chemical type that causes general corrosion for the metal alloy and performing trial and error. According to literature records (for example, “6th edition, Chemical Engineering Handbook (published by the Chemical Engineering Society, published by Maruzen Co., Ltd.)), aluminum alloys corrode with basic aqueous solutions and magnesium alloys with acidic aqueous solutions. All steel materials are corroded entirely with aqueous solutions of hydrohalic acid such as hydrochloric acid, sulfurous acid, sulfuric acid, or salts thereof. Further, a copper alloy having strong corrosion resistance is totally corroded by a strong acid oxidizing agent such as hydrogen peroxide, and a titanium alloy is totally corroded by a special acid such as oxalic acid or hydrofluoric acid.

  Some metal alloys that are actually sold in the market, such as pure copper-based copper alloys and pure titanium-based titanium alloys, have a purity of 99.9% or more and cannot be said to be alloys. Is included. Most of the materials that are actually used are mixed with various other elements in order to obtain characteristic physical properties, and few pure metal materials are mixed. In addition, most of the target metals alloyed from pure metals have improved corrosion resistance without degrading the original metal properties. Therefore, in many cases, the target chemical etching cannot be performed even in the case of using an acid base or a specific chemical substance applied with reference to the literature as described above. In short, the use of the acid-bases and specific chemicals described above is fundamental, and in practice, the concentration of the acid-base aqueous solution to be used, the liquid temperature, the immersion time, and in some cases, appropriate by trial and error while devising the additive Chemical etching is performed.

  Speaking of chemical etching, Patent Document 1 describes aluminum alloy, Patent Document 4 describes magnesium alloy, Patent Document 5 describes copper alloy, Patent Document 6 describes titanium alloy, Patent Document 7 relates to stainless steel. Description and description regarding general steel materials in Patent Document 8. For general steel materials from aluminum alloys, it is advisable to check the “chemical etching” section of these patent documents. The present invention can be applied in exactly the same manner. Therefore, these patent documents should be referred to for details. To explain the points that are generally common as work actually performed, when a metal alloy shaped product is obtained, it is first immersed in an aqueous solution in which a commercial degreasing agent for each metal is dissolved, degreased, and washed with water. This step is preferred and should always be performed because it removes most of the machine oil and finger grease deposited in the step of obtaining the metal alloy shape.

  Next, it is preferably immersed in a thinly diluted acid-base aqueous solution and washed with water. This is a process that the present inventors have called pre-acid cleaning and pre-base cleaning, and in the case of a metal species that corrodes with an acid such as general steel, it is immersed in a basic aqueous solution and washed with water, or an aluminum alloy In the case of a basic aqueous solution such as a metal species that is particularly corrosive, it is immersed in a dilute acid aqueous solution and washed with water. These are processes in which a solution opposite to the aqueous solution used for chemical etching is attached (adsorbed) to the metal alloy in advance, and the subsequent chemical etching starts without an induction period, so that the reproducibility of the process is remarkably improved. . Therefore, the preliminary acid cleaning and preliminary base cleaning steps are not essential, but are preferably employed in practice.

[Surface hardening treatment and fine etching]
Depending on the type of metal alloy, the surface has a micron-order roughness and ultra-fine irregularities are formed by performing the chemical etching (nano-order fine etching is also performed). In some cases, the natural oxide layer is thicker than the original and has been cured. That is, the metal alloy surface may satisfy the conditions (1) to (3) described above. For example, a pure titanium-based titanium alloy is also finely etched by performing only chemical etching. However, in many cases, it is necessary to perform fine etching and surface hardening treatment after forming an uneven surface of micron order by chemical etching.

  Specifically, when the metal alloy material is stainless steel, titanium alloy, or copper alloy, the fine etching of the surface is (1) the average length (RSm) of the contour curve element is 0.5 to 10 μm, In addition, it has a roughness on the order of microns with a maximum height roughness (Rz) of 0.1 to 5 μm, and (2) is preferably an ultrafine uneven shape composed of unevenness with a period of 5 nm to 300 nm. Further, when the metal alloy material is an aluminum alloy, a magnesium alloy, a copper alloy, or a general steel material, the fine etching of the surface is (1) the average length (RSm) of the contour curve element is 1 to 10 μm, and It is assumed that the maximum height roughness (Rz) has a roughness on the micron order of 0.2 to 5 μm, and (2) and an ultrafine concavo-convex shape composed of concavo-convex having a period of 5 nm to 500 nm is preferable.

  Fine etching and surface hardening treatments often suffer from unpredictable chemical phenomena. That is, there is an example in which ultra-fine irregularities are accidentally formed on the resulting surface when an oxidizing agent or the like is reacted with the metal alloy after chemical etching or chemical conversion treatment for the purpose of surface hardening treatment or surface stabilization treatment. . When a magnesium alloy is subjected to a chemical conversion treatment with a potassium permanganate aqueous solution, the surface layer that appears to be manganese oxide generated in the magnesium alloy is a rod-like shape having a diameter of 5 to 10 nm that can be finally distinguished with an electron microscope of 100,000 times. It is a complex of crystals. This sample was analyzed by XRD (X-ray diffractometer), but no diffraction lines derived from manganese oxides could be detected. Since it is clear by XPS analysis that the surface is covered with manganese oxide, it is considered that the reason why the surface could not be detected by XRD was that the crystal was a thin layer exceeding the detection limit. In short, in the magnesium alloy, the chemical conversion treatment also serves as fine etching.

  The same applies to copper alloys. When a hardening treatment is performed to change the surface of the copper alloy to cupric oxide by oxidation under a basic condition, the surface of a pure copper-based copper alloy has a shape in which a circle or a circle is distorted. The hole opening is formed on one surface and becomes a characteristic fine uneven surface. In a copper alloy that is not pure copper-based, not a concave shape but a particle size or an indefinite polygonal shape with a diameter of 10 to 150 nm is connected, and a part of the particles is melted and stacked to form an ultra fine uneven shape. Even in this case, most of the surface is covered with cupric oxide, and hardening and fine unevenness occur simultaneously.

  In general steel materials, ultra fine irregularities are often formed only by a chemical etching process. In particular, rolled steel has an ultra-fine multilayered structure with a pearlite structure and a period of 80 to 200 nm, and the pearlite structure is exposed by chemical etching to remove the surface rust and the basic shape is completed. However, since general steel materials are easily corroded in a normal environment, it is necessary to form a hard surface that does not rust by performing some chemical conversion treatment on the exposed pearlite structure. When the chemical conversion treatment was actually performed, it was found that the joining strength of the injection-bonded product varied depending on the type and degree of chemical conversion treatment (the thickness of the chemical conversion film). The bonding strength depends on whether or not the bonding force between the chemical conversion treatment layer and the steel material of the base material is sufficiently strong, and the bonding strength is mainly determined by the chemical conversion treatment type. However, if the film thickness of the chemical conversion treatment layer is too thick, the adhesive force is reduced.

  This tendency was the same for the magnesium alloy. That is, in the case of a magnesium alloy, a stronger adhesive force is observed in a thin layer in which a diffraction line is not detected by XRD, such as a manganese oxide thin layer deposited by chemical conversion treatment. In the case of magnesium alloy, when the PPS resin or the like is destroyed after the chemical conversion treatment layer is thickened, the fracture surface is mostly between the substrate metal phase and the chemical conversion film. The inventors believe that when the chemical conversion film becomes thick, the bonding force itself between the base metal phase and the chemical conversion film decreases.

  In short, in both magnesium alloys and general steel materials, if the chemical conversion treatment time is increased and the chemical conversion treatment layer is made thicker, the durability (corrosion resistance) of the adhesive will be improved, but if the chemical conversion film is made thicker, the adhesive strength will be reduced. . In the present invention, it is preferable to shorten the time rather than the chemical conversion treatment usually performed on a magnesium alloy or a general steel material. That is, other types of chemical conversion treatment materials for steel are commercially available, and some of them can be used as they are according to the treatment conditions in the present invention. It is preferable to perform processing under considerably relaxed conditions rather than the processing conditions indicated by Even in copper alloys, the surface is blackened as a copper oxide layer by oxidation treatment, but in order to improve the surface treatment performed by copper heat sinks and heat sinks, that is, radiation heat dissipation and heat absorption efficiency It is preferable to relax considerably than the blackening treatment.

  Originally, the balance between the corrosion resistance and the bonding force should be appropriately selected depending on the product, but the present inventors consider that the bonding force should be given priority. This is because the magnesium alloy, copper alloy, general steel materials that have been treated with the “new NMT” liquid, that is, the shapes made by processing these metal alloys, are subjected to the chemical conversion treatment as described above, and this is then subjected to injection molding. This is because when a PPS resin or the like is inserted into the mold and injection-bonded, the chemical film on the surface of the metal alloy may be partially crushed by a strong injection pressure in the injection mold. In addition, the shape of the cavity and the shape of the insert in the injection mold are unlikely to completely match, and when the mold is closed or the metal alloy side is bent or stretched during molding, There is a high possibility of cracks in the chemical conversion film. Therefore, in mass-produced products, it is preferable to perform additional processing such as chemical conversion treatment again on the metal resin integrated product obtained by injection joining. In short, if it is assumed that chemical conversion treatment is additionally performed, the chemical conversion treatment before the injection joining does not need to make the improvement of corrosion resistance the first priority.

[Resin composition for injection joining]
The resin for injection joining used in the present invention is a resin composition containing a highly crystalline highly crystalline resin as a main resin component. PPS, PBT, and polyamide resin can be used as the highly crystalline resin with high hardness, and the resin compositions that make up these specific resin components are roughly the following four types. That is, the first resin composition containing PPS as a main component preferably has 70 to 97% by mass of PPS and 3 to 30% by mass of polyolefin resin. The second resin composition containing PBT as a main component preferably contains 70 to 97% by mass of PBT and 3 to 30% by mass of a polyethylene terephthalate resin and / or a polyolefin resin. The third resin composition containing aromatic polyamide as a main component is a resin composition containing an aromatic polyamide resin as a main component and an aromatic polyamide resin or an aliphatic polyamide resin different from the aromatic polyamide resin as a subcomponent. In this case, the aromatic polyamide resin as the main component is preferably 70 to 95% of the polyamide resin.

  Furthermore, the 4th resin composition which has an aliphatic polyamide resin as a main component is a resin composition which has an aliphatic polyamide resin as a main component, and an aliphatic polyamide resin different from this or an aromatic polyamide resin as a subcomponent. . In this case, it is preferable that the aliphatic polyamide resin as a main component is 50 to 90% of the polyamide resin. In this way, if the main body is a highly crystalline resin with high hardness, but different types are mixed at the molecular level, even if the temperature is below the melting point and the environmental conditions are to be crystallized, the same kind is immediately obtained. Are not next to each other, and the crystallization speed is slow. In other words, it is presumed that a time lag occurs more than usual when microcrystals, which are seeds of crystals, are formed or when microcrystals grow into crystals. The reason why the resin composition using the structured resin component is convenient for injection joining so that the crystallization speed during quenching is slow is as described in the preceding sentence.

Furthermore, the resin composition to be used is one or more fillings selected from glass fiber, carbon fiber, aramid fiber, other reinforcing fiber, calcium carbonate, magnesium carbonate, silica, talc, clay, and glass powder in addition to the resin component. The material is preferably contained in an amount of 20 to 60% by mass based on the entire composition. This is because by including these fillers, the linear expansion coefficient of the resin molded product can be set to 2-3 × 10 ⁻⁵ ° C.− ¹ and can be made as small as possible. That is, the resin composition for injection joining used in the present invention may be exactly the same as the documents (Patent Documents 4 to 8) disclosed in relation to “NMT”, “New NMT” and the like.

  The polyolefin resin used for the first resin composition and the second resin composition will be described in detail. As the polyolefin resin, an ethylene resin, a propylene resin, or the like that is generally known as a polyolefin resin is used, and these resins may be commercially available. Among them, since it is possible to obtain a composite having particularly excellent adhesiveness, maleic anhydride-modified ethylene copolymer, glycidyl methacrylate-modified ethylene copolymer, glycidyl ether-modified ethylene copolymer, ethylene alkyl It is preferably an acrylate copolymer or the like.

  As the maleic anhydride-modified ethylene copolymer, for example, maleic anhydride graft-modified ethylene polymer, maleic anhydride-ethylene copolymer, ethylene-acrylic acid ester-maleic anhydride terpolymer, etc. are used. be able to. Among them, an ethylene-acrylic acid ester-maleic anhydride terpolymer is preferable because a particularly excellent composite can be obtained. Specific examples of the ethylene-acrylic acid ester-maleic anhydride terpolymer include “BONDINE” (manufactured by ARKEMA (France) ”and the like.

  As the glycidyl methacrylate-modified ethylene copolymer, for example, glycidyl methacrylate graft-modified ethylene polymer and glycidyl methacrylate-ethylene copolymer can be used. Among them, a glycidyl methacrylate-ethylene copolymer is preferable because a particularly excellent composite can be obtained. Specific examples of the glycidyl methacrylate-ethylene copolymer include “Bond First” (manufactured by Sumitomo Chemical Co., Ltd. (Tokyo, Japan)). Examples of the glycidyl ether-modified ethylene copolymer include glycidyl ether graft-modified ethylene copolymer and glycidyl ether-ethylene copolymer. Specific examples of the ethylene alkyl acrylate copolymer include “Lotryl (ARKEMA) Manufactured) ”and the like.

  In the case of a 1st resin composition, it is preferable to mix | blend 0.1-6 mass parts of polyfunctional isocyanate compounds and / or 1-25 mass parts of epoxy resins other than said polyolefin resin. These seem to work like a compatibilizer and have the effect of stabilizing the mixing of the polyolefin resin at the molecular level. As this polyfunctional isocyanate compound, a commercially available non-block type or block type compound can be used. Examples of the polyfunctional non-blocked isocyanate compound include 4,4'-diphenylmethane diisocyanate, 4,4'-diphenylpropane diisocyanate, toluene diisocyanate, phenylene diisocyanate, and bis (4-isocyanatophenyl) sulfone. Examples of the polyfunctional block type isocyanate compound include those having two or more isocyanate groups in the molecule and made inert at room temperature by reacting the isocyanate group with a volatile active hydrogen compound. The

  The type of the polyfunctional block type isocyanate compound is not particularly specified. Generally, the isocyanate group is masked by a blocking agent such as alcohols, phenols, ε-caprolactam, oximes, and active methylene compounds. Has a structured. As this polyfunctional block type isocyanate, for example, “Takenate (manufactured by Mitsui Takeda Chemical Co., Ltd., Tokyo, Japan)” and the like can be mentioned. As the epoxy resin, an epoxy resin generally known as a bisphenol A type, a cresol novolak type, or the like can be used. Examples of the bisphenol A type epoxy resin include “Epicoat (manufactured by Japan Epoxy Resin Co., Ltd. (Tokyo, Japan))”. Examples of the cresol novolac type epoxy resin include “Epiclon” (manufactured by DIC Corporation (Tokyo, Japan)).

  Next, the details of the third resin composition and the fourth resin composition will be described. Specifically, the aromatic polyamide which is the main component in the third resin composition is preferably a polyamide from terephthalic acid and hexamethylene diamine (hereinafter referred to as “nylon 6T”), isophthalic acid and hexamethylene diamine. Polyamide (hereinafter referred to as “nylon 6I”). Nylon 6 and nylon 66 are preferable as the aliphatic polyamide as the main component in the fourth resin composition.

[Polyolefin resin]
In the present invention, the polyolefin resin is used for masking a metal alloy or a composite. That is, the polyolefin resin is once injection-bonded to the metal alloy or composite, but is finally removed from the composite. Details will be described in “masking injection joining method” described later. The resin used is not reactive or water-absorbing with respect to etching aqueous solutions and chemical treatment chemicals for various metal alloys, and is a resin composition used for injection joining with metal alloys (that is, not for masking) Resin) is required to be non-adhesive when injected onto a molded product. For that reason, a polyolefin resin can be used.

  In order to mask the metal alloy before the liquid treatment in “NMT” and “New NMT”, the polyolefin resin to be used is a mold temperature at the time of injection joining because the molded product is put into an injection mold. The molded product must withstand 140 ° C. A polypropylene resin containing a large amount of filler (hereinafter referred to as “PP resin”) is preferred for use, and the filler contained is preferably a material that can withstand acid-base aqueous solutions. Specifically, glass fiber, silica, talc, glass powder, and the like are preferable, and the addition amount is preferably 20 to 60% of the entire composition. Although glass fiber and glass powder may react with a basic aqueous solution, the strongest basic aqueous solution is a desmutting solution at the time of magnesium alloy treatment, and is a 10-20% aqueous solution of caustic soda at a temperature of about 70 ° C. Even if the PP resin containing glass fiber is immersed in this intense strong basic aqueous solution, a part of the glass fiber exposed from the PP resin will be dissolved, but it can be used because there is no further change.

  On the other hand, the polyolefin resin used in the two-color molding is further injected from above the composite of the metal alloy and resin after injection joining. For this reason, if it is melted with the resin molding used for injection joining, it cannot be peeled off later. In this respect, a resin having a melting point of 200 ° C. or lower is preferable. On the other hand, this polyolefin resin must withstand various chemical conversion treatments, electrolytic oxidation, and other treatments in a composite obtained by injection joining while protecting the boundary line where the metal alloy and the resin are joined. . The maximum temperature for electrolytic oxidation of aluminum alloy, that is, anodizing, is about 100 ° C. during chemical polishing, dyeing, and sealing, which is considered to be the maximum temperature. From these, the polyolefin resin composition preferred for use is preferably a PP resin containing glass fibers and the like as described above.

[Injection joining]
In the injection joining process of the present invention, the above-mentioned resin composition for injection joining (for masking) is formed by inserting a metal alloy shaped article that has been liquid-treated with the above-mentioned “NMT” and “new NMT” into an injection mold. Is a step of producing a composite in which the metal alloy and the resin are integrated. The injection conditions at that time will be described. The mold temperature is preferably 100 ° C. or higher, more preferably 110 to 130 ° C. Although the injection temperature, injection pressure, and injection speed are not particularly different from those of ordinary injection molding, it is preferable to increase the injection speed and injection pressure. Next, a method for producing a metal alloy resin composite proposed in the present invention will be described. In other words, there are two types of “masking injection joining methods”, the first masking injection joining method for masking before liquid treatment and the second masking injection for masking after liquid treatment and before surface processing of the composite. It is a joining method.

[First masking injection joining method / Masking before liquid treatment]
The first masking injection joining method will be described with reference to FIG. 1, which shows a schematic process flow. Starting from FIG. 1 (a), it reaches FIG. 1 (e). FIG. 1A shows a small exterior case 1 made of a thin plate material made of a metal alloy used for a mobile electronic device case or the like. The material of the small exterior case 1 is SUS304, and this thin plate material is processed by press molding. The press-molded product is inserted into an injection mold (not shown), and PP resin is injected (steps from FIG. 1A to FIG. 1B). FIG. 1B shows a runner 2 and a PP resin portion 3 injection-molded through a gate. After injection joining, the injection mold is opened, the small outer case 1 in which the PP resin portion 3 is molded is released, and this is subjected to a liquid treatment (see FIG. 1C). That is, if the small exterior case 1 is a part made of SUS304, the “new NMT” liquid treatment for SUS304 is performed and dried.

  After completion of the liquid treatment, the exposed metal surface 6 that is not masked with PP resin becomes a liquid-treated surface, and is roughened, so when the material is SUS304, it becomes slightly darker. This is inserted into another injection mold, and the aforementioned resin for injection joining is injected. This is the aforementioned injection joining process. FIG. 1D shows a composite of a metal alloy and a resin obtained through an injection joining process, and bosses and ribs 5 are injection joined to the treated surface of the metal alloy. The PP resin part 3 is peeled off from the composite is the composite as the final product obtained in the present invention, which is shown in FIG. In the appearance part of the product (the range masked by the PP resin part 3), the original surface state of the metal alloy shape is maintained (the state as shown in FIG. 1A). That is, if the metal alloy shape is a mirror-finished SUS304 or SUS304BA material, the surface is maintained as it is. With this “masking injection joining method”, metal alloy parts that had been specially surface-processed, such as mirror processing by liquid processing, can be used for liquid processing for injection bonding. Can be prevented.

[Second masking injection joining method / masking before surface processing]
Next, the second masking injection joining method will be described. This is a method using a two-color molding machine, and the flow of the process is shown schematically in FIGS. 2 to 4, and will be described with reference to FIGS. The outline of the process starts from FIG. 2 (a) and reaches FIG. 4 (i). FIG. 2A shows a small-sized exterior case 10 made of a metal alloy made of sheet metal, which is used for a mobile electronic device case or the like. The metal alloy is an aluminum alloy product such as A5052 aluminum alloy. The small exterior case 10 is first subjected to a liquid treatment for injection joining (FIG. 2B) and then dried. Since this aluminum alloy is A5052, the liquid treatment in the “NMT” described above is performed.

  After the liquid treatment, ultra-fine irregularities are formed on the surface of the small outer case 10. After this metal alloy piece 10 is inserted into the movable side mold plate 11 of the two-color molding machine, the first mold is closed. That is, after the movable mold plate 11, the fixed mold plate 12, and the fixed mold plate 13 constituting the first mold are closed, the molten injection joining resin is injected (step of FIG. 2C). ). As a result, the injection joining resin is injection joined from the runner 14 of the fixed side mold plate 13 to the inner surface side of the small exterior case 10 via the fixed side mold plate 12 to form the boss 15. As a result, the complex shown in FIG. 3 (d) is obtained. FIG. 3D shows the boss 15 generated by injection joining.

  Next, the first mold is opened, and the movable composite plate 11 is maintained while maintaining the state where the obtained composite is inserted into the movable mold plate 11 as it is (the state shown in FIG. 3D). Is moved toward the second mold (step from FIG. 3D to FIG. 3E). The second mold is composed of a movable mold plate 11, a fixed mold plate 16 and a fixed mold plate 17, and the second mold movable mold plate 11, fixed mold plate 16 and fixed mold plate 17. Is closed (see FIG. 3E). In this state, PP resin is injected. As a result, PP resin is injected from the runner 18 of the fixed side mold plate 17 to the inner surface side of the small exterior case 10 through the runner 19 of the fixed side mold plate 16, and the boss 15 obtained in FIG. Is formed so as to cover the base of the film (see FIG. 3 (e)). Next, when a 2nd metal mold | die is opened and a molded article is taken out, the composite_body | complex shown in FIG.3 (f) will be obtained as a result. That is, on the inner surface side of the small exterior case 10, a composite in a state in which the periphery of the base portion of the boss 15 that is a molded product of injection-bonded resin is masked with the PP resin portion 20 that is a molded product of PP resin. obtain.

  Next, the composite consisting of the metal alloy and the resin is subjected to an alumite forming step (see FIG. 4G). As a result, in the surface of the small exterior case 10, a portion where the metal alloy is exposed (a portion indicated by a thick line shown in FIG. 4H) is subjected to the anodizing process. That is, the exposed portion of the aluminum alloy is exposed to a strong base and a strong acid, and then anodized. However, the base portion of the boss 15 that has been injection-bonded is protected by the PP resin portion 20 and is not subject to any erosion. After the anodization is completed, the PP resin part 20 is peeled off, washed thoroughly with water just in case, and dried to complete the anodized product as the final product (see FIG. 4 (i)).

  Similar processing methods can be used with magnesium alloy parts. In the case of a magnesium alloy part, after the two-color molding, the composite shown in FIG. 3 (f) is subjected to chemical conversion treatment again, and instead of the anodizing process of FIG. It passes. By this liquid treatment process, scratches and cracks on the film generated in the first liquid treatment (liquid treatment shown in FIG. 2B including the chemical conversion treatment for injection joining) are formed on the surface of the magnesium alloy produced in the injection joining process. Can be covered with a new chemical conversion film. The composite in front of the final product (see FIG. 4 (h)) can be directly subjected to a paint baking process, and then the PP resin portion 20 can be peeled off.

  As described above in detail, the method for producing a composite of a metal alloy and a resin according to the present invention is such that the surface of the metal alloy has a roughness on the order of microns, has an ultra-fine irregular shape, and is a thin layer of metal oxide. A composite in which the metal alloy and the resin are strongly bonded can be obtained by performing a surface treatment so as to be covered with and injection-bonding a PBT-based resin, a PPS-based resin, or a polyamide-based resin. Moreover, since the said surface treatment is performed after masking with polyolefin resin, it can maintain as it is, without changing the surface state which the metal alloy surface had. Furthermore, with regard to metal species such as aluminum alloys, magnesium alloys, and general steel materials, after obtaining composites of these metal alloys and resins, the composites are anodized to improve decoration and weather resistance. It has become possible to perform various chemical treatments.

Hereinafter, embodiments of the present invention will be described by way of examples. The equipment used for measurement etc. is shown below.
(A) X-ray surface observation (XPS observation)
ESCA “AXIS-Nova (Kuratos / Shimadzu Corporation (Kyoto Prefecture, Japan))” in the form of observing constituent elements on a surface having a diameter of several μm in a depth range of 1 to 2 nm was used.
(B) Electron beam surface observation (EPMA observation)
An electron beam microanalyzer “EPMA 1600 (manufactured by Shimadzu Corporation)” in the form of observing constituent elements on a surface having a diameter of several μm up to several μm in depth was used.
(C) Electron Microscope Observation Using a SEM type electron microscope “JSM-6700F (JEOL Ltd. (Tokyo, Japan))”, observation was performed at 1 to 2 KV.
(D) Scanning probe microscope observation “SPM-9600 (manufactured by Shimadzu Corporation)” was used.
(E) Measurement of Bonding Strength of Composite Material Using a tensile tester “Model 1323 (manufactured by Aiko Engineering Co., Ltd. (Osaka, Japan))”, the shear breaking strength was measured at a pulling speed of 10 mm / min.

[Preparation Example 1 (Preparation Example of PPS Composition)]
A 50 liter autoclave equipped with a stirrer was charged with 6,214 g of Na ₂ S · 2.9H ₂ O and 17,000 g of N-methyl-2-pyrrolidone and gradually raised to 205 ° C. while stirring under a nitrogen stream. Warm and distill off 1,355 g of water. After the system was cooled to 140 ° C., 7160 g of p-dichlorobenzene and 5,000 g of N-methyl-2-pyrrolidone were added, and the system was sealed under a nitrogen stream. This system was heated to 225 ° C. over 2 hours, polymerized at this temperature of 225 ° C. for 2 hours, then heated to 250 ° C. over 30 minutes, and further polymerized at 250 ° C. for 3 hours. After completion of these polymerizations, the mixture was cooled to room temperature, and the polymer was separated by a centrifuge. The polymer was repeatedly washed with warm water and dried at 100 ° C. for a whole day and night to obtain a PPS having a melt viscosity of 280 poise (hereinafter referred to as PPS (1)).

  This PPS (1) was further cured at a temperature of 250 ° C. for 3 hours under a nitrogen atmosphere to obtain PPS (hereinafter referred to as PPS (2)). The resulting PPS (2) had a melt viscosity of 400 poise. 6.0 kg of the obtained PPS (2), 1.5 kg of ethylene-acrylic acid ester-maleic anhydride terpolymer “Bondyne TX8030 (manufactured by ARKEMA)”, epoxy resin “Epicoat 1004 (Japan Epoxy) Resin Co., Ltd.) "was mixed with 0.5 kg in advance with a tumbler. Then, with a twin screw extruder “TEM-35B (manufactured by Toshiba Machine Co., Ltd.)”, glass fiber “RES03-TP91 (manufactured by Nippon Sheet Glass Co., Ltd. (Tokyo, Japan))” having an average fiber diameter of 9 μm and a fiber length of 3 mm was obtained. While being supplied from the side feeder so that the addition amount was 20% by mass, the mixture was melt-kneaded at a cylinder temperature of 300 ° C. to obtain a pelletized PPS composition (1). The obtained PPS composition (1) was dried at 175 ° C. for 5 hours.

[Example 2 of adjustment (adjustment of PBT composition)]
6.0 kg of PBT resin “Toraycon 1401X31 (manufactured by Toray Industries, Inc., Tokyo, Japan)”, 0.5 kg of PET resin “TR-4550BH (manufactured by Teijin Chemicals)”, ethylene-acrylic acid ester-maleic anhydride A ternary copolymer “Bondyne TX8030 (manufactured by ARKEMA)” 0.5 kg and an epoxy resin “Epicoat 1004 (manufactured by Japan Epoxy Resin Co., Ltd.)” 0.1 kg were uniformly mixed in advance with a tumbler. Then, with a twin screw extruder “TEM-35B (Toshiba Machine Co., Ltd. (Shizuoka, Japan))”, glass fiber “RES03-TP91 (Nippon Sheet Glass Co., Ltd.)” having an average fiber diameter of 9 μm and a fiber length of 3 mm. Was fed from the side feeder so that the addition amount was 30% by mass, and melt-kneaded at a cylinder temperature of 270 ° C. to obtain a pelletized PBT composition (1). The obtained PBT composition (1) was dried at a temperature of 150 ° C. for 5 hours.

[Adjustment Example 3 (Adjustment of aromatic polyamide composition)]
Nylon 6T, which is a polyamide from terephthalic acid and hexamethylene diamine, nylon 6I, which is a polyamide from isophthalic acid and hexamethylene diamine, and a laboratory prototype of nylon 6 were obtained from Toray Industries, Inc. in an amount of 50 kg each. 4.5 kg of nylon 6I and 0.5 kg of nylon 6 were taken and mixed uniformly with a tumbler. Thereafter, the glass fiber “RES03-TP91 (manufactured by Nippon Sheet Glass Co., Ltd.)” having an average fiber diameter of 9 μm and a fiber length of 3 mm is produced on the mixture using a twin screw extruder “TEM-35B (manufactured by Toshiba Machine Co., Ltd.)”. While supplying from the side feeder such that the amount added was 30% by mass, the mixture was melt-kneaded at a cylinder temperature of 300 ° C. to obtain a pelletized aromatic polyamide composition (1). The obtained aromatic polyamide composition (1) was dried at 80 ° C. for 12 hours.

[Adjustment Example 4 (Adjustment of aliphatic polyamide-based composition)]
Laboratory prototypes of nylon 6I, which is a polyamide from isophthalic acid and hexamethylene diamine, and nylon 66 were obtained from Toray Industries, Inc. in an amount of 50 kg each. 5 kg of nylon 66 and 0.5 kg of nylon 6I were taken and mixed uniformly with a tumbler. Thereafter, the glass fiber “RES03-TP91 (manufactured by Nippon Sheet Glass Co., Ltd.)” having an average fiber diameter of 9 μm and a fiber length of 3 mm is produced on the mixture using a twin screw extruder “TEM-35B (manufactured by Toshiba Machine Co., Ltd.)”. While being supplied from the side feeder so that the addition amount was 30% by mass, the mixture was melt-kneaded at a cylinder temperature of 300 ° C. to obtain a pelleted aliphatic polyamide-based composition (1). The obtained aliphatic polyamide-based composition (1) was dried at a temperature of 80 ° C. for 12 hours.

  In Examples 1, 2, and 3 shown below, the PPS composition (1) is used as the resin for injection joining. Instead, the PBT composition (1) obtained by the above adjustment is used. An aromatic polyamide-based composition (1) or an aliphatic polyamide-based composition (1) can be used.

(Stainless steel composite (1))
First, a small outer case 1 was formed from SUS304BA stainless steel having a thickness of 1 mm by press molding (see FIG. 1A). This is inserted into an injection mold, heat resistant PP resin containing 30% glass fiber is injected, and as shown in FIG. 1B, stainless steel (small outer case 1) and PP resin (PP resin part) The composite of 3) was obtained. Next, this complex was subjected to a liquid treatment. That is, water is prepared in a dipping bath, and a commercially available aluminum alloy degreasing agent “NE-6” (manufactured by Meltex Co., Ltd. (Tokyo, Japan)) is added thereto, and the temperature is 60 ° C. and the concentration is 7.5%. An aqueous solution of The composite was immersed in this aqueous solution for 7 minutes and then thoroughly washed with water. Next, a 1.5% strength aqueous caustic soda solution at 40 ° C. was prepared in another dipping bath, and the composite was dipped in this for 1 minute, and then thoroughly washed with water.

  Next, an aqueous solution containing 1% ammonium hydrogen fluoride at a concentration of 1% and 5% sulfuric acid at a temperature of 65 ° C. was prepared in another immersion bath, and the integrated product was immersed for 8 minutes. Washed well with water. Next, a 3% concentration nitric acid aqueous solution having a temperature of 40 ° C. was prepared in another dipping bath, and the composite was dipped in this for 3 minutes, and then washed well with water. Next, the composite was placed in a warm air dryer at 90 ° C. for 30 minutes and dried. The composite after drying was inserted into an injection mold, and the PPS composition (1) described above was injection joined to obtain the composite shown in FIG. The mold temperature at this time was 120 ° C. Thereafter, the PP resin part 3 was peeled off from the composite to obtain a composite (see FIG. 1 (e)) as a final product.

(Stainless steel composite (2))
The same experiment as in Example 1 was performed. However, although it is the same until the liquid processing and drying process of FIG.1 (c), the PP resin part 3 was peeled from the composite_body | complex before subsequent injection joining. At this time, the small exterior case 10 (stainless steel) from which the PP resin portion 3 was peeled maintained the original mirror surface on the masked appearance side (the left side surface in FIG. 1A). On the other hand, with respect to the inner side (right side in FIG. 1) where the liquid treatment was performed, the masked area (surrounding part) maintained the mirror surface, but the unmasked central part was dark. It was a rough surface (surface having surface roughness).

  The small exterior case 10 in this state was inserted into an injection mold, and the PPS composition (1) was injection-bonded to obtain a composite as a final product (see FIG. 1 (e)). The mold temperature at this time was 120 ° C. When Examples 1 and 2 are compared, in Example 1, the positioning of the PPS composition (1) is difficult due to the influence of the masking resin (PP resin part 3) in the injection joining of the PPS composition (1). It is somewhat difficult that burrs are likely to occur. On the other hand, in Example 2, it is difficult that the mirror surface is easily damaged unless the mold surface in contact with the appearance side of the stainless steel is polished well.

(Aluminum alloy composite)
A small exterior case 10 was formed by press molding from an A5052 aluminum alloy having a thickness of 1 mm having the shape shown in FIG. 2A (FIG. 2A). This was liquid-treated and dried (FIG. 2 (b)). That is, water was prepared in a dipping tank, and a commercially available aluminum alloy degreasing agent “NE-6 (manufactured by Meltex Co., Ltd.)” was added to form an aqueous solution at 60 ° C. and a concentration of 7.5%. The small exterior case 10 (aluminum alloy) was immersed in this aqueous solution for 7 minutes, and then thoroughly washed with water. Subsequently, a 1% hydrochloric acid aqueous solution having a temperature of 40 ° C. was prepared in another dipping bath, and the small outer case 10 was dipped in this for 1 minute, and then thoroughly washed with water. Next, a 1.5% strength aqueous caustic soda solution at 40 ° C. was prepared in another dipping bath, and the small outer case 10 was dipped in this for 1 minute, and then thoroughly washed with water.

  Next, a 3% nitric acid aqueous solution having a temperature of 40 ° C. was prepared in another dipping bath, and the small outer case 10 was dipped in this for 1 minute, and then thoroughly washed with water. Next, an aqueous solution containing 3.5% monohydric hydrazine at a temperature of 60 ° C. was prepared in another dipping bath, and the small exterior case 10 was dipped in this for 1 minute, and then thoroughly washed with water. Next, the small outer case 10 was put in a warm air dryer set to a temperature of 67 ° C. for 15 minutes and dried. After drying, the small outer case 10 (aluminum alloy) was wrapped together with aluminum foil, and further sealed in a plastic bag. This is the “NMT” type liquid treatment according to Patent Document 1.

  As shown in FIG. 2C, the small exterior case 10 after the liquid treatment is inserted into the movable mold plate 11 of the two-color molding machine, and the fixed mold plate 12 and the fixed mold that constitute the first mold. The template 13 was clamped, and the injection joining resin was injected via the sprue and the runner 14. The movable mold plate 11 is a movable mold plate of the first mold and at the same time a movable mold plate of the second mold. The PPS composition (1) was used as the injection resin. Although the mold temperature of the fixed side mold plate 12 is set to 130 ° C. and the mold temperature of the movable side mold plate 11 is set to 100 ° C., the resin composition is heated to a temperature of 300 ° C. under this mold temperature condition. The resin boss 15 was injected and joined to the aluminum alloy shaped article 10 at a temperature of 0 ° C.

  Next, it was separated from the fixed side mold plate 12 with the small exterior case 10 attached to the movable side mold plate 11 (see FIG. 3D). In this state, the movable mold plate 11 is moved to the second injection molding machine, and the injection mold is replaced with the movable mold plate 11 and the fixed mold constituting the second mold as shown in FIG. The plate 16 and the fixed-side template 17 were used. A heat-resistant PP resin containing 30% glass fiber was injected into the mold. At this time, the mold temperature of the fixed side mold plate 16 is 80 ° C., and the mold temperature of the movable side mold plate 11 is 100 ° C. A composite released from the two-color molding machine is shown in FIG. As shown in the figure, the joining boundary line portion formed by the boss 15 and the small exterior case 10 by injection joining is masked by the PP resin portion 20. This composite was left in a hot air dryer set at a temperature of 130 ° C. for one day and night (24 hours) to eliminate internal distortion of the joint surface due to molding shrinkage after injection joining.

  Next, the complex was subjected to normal-type colored alumite treatment by requesting a company that performs alumite treatment. The conditions of the pretreatment in the normal type anodizing are as follows: the initial alkaline etching is performed by immersing a caustic soda aqueous solution having a concentration of about 5% at about 80 ° C. for about 15 seconds, and the subsequent chemical polishing is 50% nitric acid at 80 to 90 ° C. Soak for about 5 seconds. In fact, the composite obtained by injection-bonding to the small exterior case 10 (aluminum alloy) using the PPS resin described above can be anodized without masking with PP resin as in the present invention. Even if oxidation, dyeing and sealing are performed to form so-called alumite, the bonding strength does not decrease.

  However, in order to anodize the surface of the aluminum alloy so that the bonding force does not decrease, the pretreatment of the anodization is not as described above, and it is necessary to make the treatment lighter. For example, alkaline etching is performed by immersing a 1.5% strength aqueous caustic soda solution at a temperature of 40 ° C. for about 30 seconds to remove the adhered dirt together with some aluminum, and then stop the chemical polishing. It is immersed in an aqueous nitric acid solution having a concentration of about 3% so as to add a treatment to neutralize and remove the attached sodium ions.

  If the composite is processed by the usual pretreatment for anodizing as described above, the aluminum alloy dissolves vigorously, and the aluminum melts in the vicinity of the joint with the resin and the resin is not affected. If it is, the root will be lost, and more precisely, a pocket will be created. If the aluminum alloy is formed into a pocket shape that is dug in the boundary portion of the joint, it causes various problems and causes problems in the joint itself. However, by applying the present invention, since the joint portion is protected with PP resin, the above-described normal pretreatment can be performed.

  Next, the obtained composite was subjected to normal anodic oxidation, dyeing and sealing, finally washed thoroughly with pure water, and then placed in a hot air dryer at 90 ° C. for 15 minutes and dried. Next, the PP resin portion 20 that had masked and covered the composite (see FIG. 4H) was peeled off using a nipper. The final composite obtained by peeling off the PP resin is again inserted into a jig for immersion, immersed in a water immersion tank in which pure water is stored, rocked for 15 seconds in this, lifted, and again It put into the dryer mentioned above and dried for 15 minutes at the temperature of 90 degreeC. In the final product obtained (see FIG. 4 (i)), the outer peripheral line of the joining surface by injection joining (the base portion of the boss 15 covered with the PP resin part 20) is clean and white powder is not generated at all. There wasn't.

1 (a) to 1 (e) are process diagrams showing an outline of the steps of a method for producing a stainless steel composite. 2A to 2C are process diagrams of the first half showing an outline of manufacturing a press-formed aluminum alloy composite used for a mobile electronic device case or the like. FIGS. 3D to 3F are intermediate process diagrams showing an outline of manufacturing a press-formed aluminum alloy composite used for a mobile electronic device case or the like. FIGS. 4G to 4I are final process diagrams showing an outline of manufacturing a press-formed aluminum alloy composite used for a mobile electronic device case or the like.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Small exterior case 2 ... Runner 3 ... PP resin part 4 ... Runner 5 ... Rib 6 ... Metal exposure surface 10 ... Small exterior case 11 ... Movable side template 12 ... Fixed side template 13 of 1st metal mold | die 1st Fixed mold plate 14 of the mold ... Runner 15 ... Boss 16 ... Fixed mold plate 17 of the second mold ... Fixed mold plate 18 of the second mold ... Runner 19 ... Runner 20 ... PP resin part

Claims (5)

A shaping step of shaping the metal alloy material into a predetermined shape;
The metal alloy shaped product obtained by the shaping step is inserted into a first injection mold, and a polyolefin resin is injected into a predetermined region of the metal alloy shaped product. A first injection joining step to obtain a covered first composite;
By performing chemical etching on the first composite, the surface of the metal alloy portion of the first composite is (1) the average length (RSm) of the contour curve elements is 0.5 to 10 μm and the maximum It has a roughness on the order of microns with a height roughness (Rz) of 0.1 to 5 μm, (2) and has an ultrafine concavo-convex shape consisting of concavo-convex with a period of 5 nm to 300 nm, (3) and a metal oxide A surface treatment step that is covered with a thin layer of
A resin composition comprising a polyphenylene sulfide resin as a main resin component and a polybutylene terephthalate resin with respect to the first composite, the first composite having undergone the surface treatment step being inserted into a second injection mold. , A resin composition comprising an aromatic polyamide resin as a main component, and a different type of aromatic polyamide resin or aliphatic polyamide resin as a subsidiary component, and the aliphatic polyamide resin One or more resin compositions selected from the group consisting of a resin composition comprising a different type of aliphatic polyamide resin or aromatic polyamide resin as a subsidiary component, and the injected resin A second injection joining step of obtaining a second composite in which the composition and the first composite are joined;
A metal alloy-resin composite comprising: a removal step of removing the polyolefin resin from the second composite to obtain a third composite in which the predetermined region is maintained in a state before the surface treatment step. Manufacturing method. A shaping step of shaping the metal alloy material into a predetermined shape;
By performing chemical etching on the metal alloy shape obtained by the shaping step, the surface of the metal alloy shape is (1) the average length (RSm) of the contour curve elements is 1 to 10 μm and the maximum It has a roughness on the order of microns with a height roughness (Rz) of 0.2 to 5 μm, (2) has an ultra-fine uneven shape consisting of unevenness with a period of 5 nm to 500 nm, (3) and a metal oxide A surface treatment step that is covered with a thin layer of
The metal alloy shaped article that has undergone the surface treatment step is inserted into a first mold for two-color molding, and a resin composition containing polyphenylene sulfide resin as a main resin component in the first mold, polybutylene terephthalate resin The main resin component, an aromatic polyamide resin as a main component, and a different aromatic polyamide resin or aliphatic polyamide resin as a subcomponent, and an aliphatic polyamide resin as a main component And at least one resin composition selected from a different aliphatic polyamide resin or a resin composition comprising an aromatic polyamide resin as a subsidiary component, and the injected resin composition and the metal alloy A first injection joining step of obtaining a first composite joined with a shaped object;
The first composite is inserted into a second mold, a polyolefin resin is injected into the second mold, and a second composite is obtained in which the polyolefin resin and the first composite are joined. The injection joining process of
A surface processing step of applying a predetermined surface processing to the second composite;
By removing the polyolefin resin from the second composite that has undergone the surface processing step, a third composite in which the range in which the polyolefin resin is bonded is maintained in the state before the surface processing step is obtained. A method for producing a composite of a metal alloy and a resin comprising a removing step. In the method for producing a composite of a metal alloy and a resin according to claim 1,
The method for producing a composite of a metal alloy and a resin, wherein the metal alloy material is one selected from stainless steel, titanium alloy, and copper alloy. In the method for producing a composite of a metal alloy and a resin according to claim 2,
The said metal alloy material is 1 type selected from an aluminum alloy, a magnesium alloy, a copper alloy, and a general steel material, The manufacturing method of the composite of a metal alloy and resin characterized by the above-mentioned. In the method for producing a composite of a metal alloy and a resin according to claim 2,
While maintaining the state where the first complex formed by the first mold is inserted into the movable mold plate of the first mold, the movable mold plate is moved to the movable side of the second mold. A method for producing a composite of a metal alloy and a resin, characterized by comprising a template.

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