JP2012232583A - Composite of aluminum alloy and resin and method for manufacturing the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a composite of the aluminum alloy and resin with high water resistance.SOLUTION: A super-minute asperity surface of 20-40 nm cycle is formed by immersing the aluminum alloy in the hydration hydrazine aqueous solution of a several % concentration adjusted to 45-65°C in one to a few minutes, then the hydrazine is adsorbed in the aluminum alloy surface by immersing the aluminum alloy in the hydration hydrazine aqueous solution of 0.05-1% concentration assumed to be 15-55°C for a few minutes, and washing it in clear water, and next, drying it with the low temperature at 50-70°C. This is inserted in the mold for the injection formation, PPS resin composition 53 is injected into the surface and is connected to the aluminum alloy. An aluminum hydroxide layer 54 is formed on the aluminum alloy surface, by immersing the obtained injection joining object in the ion exchange water of 98°C and further heating it for one hour at 170°C.

Description

  The present invention relates to a composite comprising an aluminum alloy and a polyphenylene sulfide (hereinafter referred to as “PPS”) resin composition. The composite according to the present invention is particularly suitable for parts such as transport machines and industrial machines used outdoors, construction materials, and the like.

  Technology for strongly bonding metals or metal and synthetic resin is required not only in parts manufacturing industries such as automobiles, home appliances, and industrial equipment, but also in a wide range of industrial fields. For this reason, many adhesives have been developed. Yes. Such joining technology is a key technology in all manufacturing industries.

  Research has also been conducted on bonding methods that do not use an adhesive. Among them, “NMT (abbreviation of Nano molding technology)” developed by the present inventors has a great influence on the manufacturing industry. NMT is a joining technique between an aluminum alloy and a resin composition. At the same time as molding a resin part by injecting a molten engineering resin into an aluminum alloy that has been inserted into an injection mold in advance. And an aluminum alloy (hereinafter abbreviated as “injection joining”). Patent Document 1 discloses a technique in which a polybutylene terephthalate (hereinafter referred to as “PBT”) resin composition is injection-bonded to an aluminum alloy subjected to a specific surface treatment. Patent Document 2 discloses a technique in which a PPS resin composition is injection-bonded to an aluminum alloy subjected to a specific surface treatment. The principle of injection joining in Patent Document 1 and Patent Document 2 will be briefly described as follows.

(NMT)
As requirements for NMT, there are two conditions for the aluminum alloy and one condition for the resin composition. Two conditions of the aluminum alloy are shown below.
(1) The surface of the aluminum alloy is covered with ultra fine irregularities with a period of 20 to 80 nm (preferably with a period of 20 to 50 nm), or ultra fine recesses or ultra fine protrusions with a diameter of 20 to 80 nm (preferably with a diameter of 20 to 50 nm). Being. As an index, RSm is preferably covered with ultra fine irregularities having a thickness of 20 nm to 80 nm. Moreover, Rz may be covered with an ultrafine concave portion or an ultrafine convex portion having a diameter of 20 to 80 nm. Furthermore, it may be covered with ultra-fine irregularities with RSm of 20 nm to 80 nm and Rz of 20 to 80 nm. RSm is the average length of contour curve elements defined in Japanese Industrial Standards (JIS B 0601: 2001, ISO 4287: 1997), and Rz is Japanese Industrial Standards (JIS B 0601: 2001, ISO 4287: 1997) Is the maximum height specified. Here, the surface layer of this aluminum alloy is a thin layer of aluminum oxide, and its thickness is 3 nm or more.
(2) Ammonia, hydrazine, or a water-soluble amine compound is chemically adsorbed on the aluminum alloy surface.
On the other hand, the conditions of the resin composition are as follows.
(3) The main component is a hard crystalline thermoplastic resin that can react with a broadly defined amine compound such as ammonia, hydrazine, or water-soluble amines at 150 to 200 ° C. Specifically, it is a resin composition containing PBT, PPS, polyamide resin or the like as a main component.

Here, when the resin composition contains PBT or PPS as a main component (that is, satisfies the condition of (3)) and contains 10 to 40% by mass of glass fiber, (1) and (2) The aluminum alloy that satisfies the conditions and the unprecedented strong bonding strength were exhibited. When the aluminum alloy and the resin composition are both plate-like materials, and the composite body in which both are joined at a constant area (0.5 cm ² ) is subjected to a tensile test and is broken, it shows a breaking force of 20 to 25 MPa. It was.

In NMT, in order to obtain a strong bonding force, the condition 1 is further added to the resin composition side.
(4) A polymer different from the main component polymer is included, and most of the different polymer is mixed with the main component crystalline thermoplastic resin at a molecular level.
The purpose of adding this condition (4) is to reduce the rate of crystallization when the molten resin composition is quenched. It is thought that if different polymers are mixed at the molecular level, the presence of the different polymers becomes a hindrance when moving from the molten state to crystallization, and it becomes difficult to align, and as a result, the crystallization rate during rapid cooling is suppressed. based on. Thus, it was predicted that the ultrafine irregularities sufficiently penetrate before the resin composition was cured, thereby contributing to an improvement in bonding strength. This prediction was correct as a result.

The resin composition contains PBT or PPS as a main component (that is, satisfies the condition (3)), satisfies the condition (4) (compounds different types of polymers), and further contains 10 to 40% by mass of glass fiber. When it was included, it showed an extremely strong bonding force with the aluminum alloy satisfying the conditions (1) and (2). When the aluminum alloy and the resin composition are both plate-like materials and the composite body in which both are joined at a constant area (about 0.5 to 0.8 cm ² ) is pulled and broken, 25-35 MPa was shown. When a resin composition obtained by compounding different types of polyamide resins was used, a breaking force of 20 to 30 MPa was exhibited.

WO 03/064150 A1 WO 2004/041532 A1 Japanese Patent Application No. 2010-264652 Japanese Patent No. 4452220 Japanese Patent No. 4452256

  A composite of an aluminum alloy and a PPS resin composition obtained by NMT is most suitable for electronic devices such as mobile phones, mobile computers, and data projectors. However, in order to use this composite for transportation equipment such as automobiles, bicycles and airplanes, industrial machines used outdoors, and construction materials, not only the bonding strength of aluminum alloy and PPS resin composition, but also weather resistance. You must combine sex. The weather resistance required for the above uses is resistance to sunlight, resistance to rainwater, sewage, seawater in which moisture and moisture, especially salty seawater dissolved, long-term in an environment of temperatures from -40 to + 100 ° C. That can withstand long-term use in an environment where these conditions are combined.

  The present invention has been made based on such a technical background, and its object is to provide a composite having excellent weather resistance and a method for producing the same while achieving strong bonding between an aluminum alloy and a PPS resin composition. It is to provide.

  Coating is the most effective for ensuring the weather resistance of the composite. In the paint industry, two-layer or three-layer coating is applied to an aluminum alloy to block sunlight, and to prevent sewage and salt water. However, oxygen, nitrogen and water molecules cannot be completely blocked, and it is difficult to completely block chlorine ions and sodium ions contained in salt water. The coating film is an entangled polymer, and small molecules can pass through the gaps between the entangled molecular chains. The part exposed from the coating film may be scratched, and the scratch may reach the metal phase, from which rust may be generated. In order to ensure weather resistance, the speed at which the rust spreads to the periphery must be suppressed. Taking these into consideration, the actual aluminum alloy material is subjected to surface treatment before painting in order to obtain weather resistance. Usually, chemical conversion treatment such as chromate treatment and boehmite treatment is performed. The purpose of the chemical conversion treatment is to improve the adhesion between the chemical conversion treatment layer and the coating film to improve the component protection by the coating film, and to make the chemical conversion treatment layer itself low reactive to sodium ions and chlorine ions. The purpose is to prevent these ions from entering the metal phase.

  Even in the case where weather resistance is imparted to the injection-bonded product of the aluminum alloy and the PPS resin composition obtained by NMT, it is necessary to apply a chemical treatment to the exposed portion of the aluminum alloy and apply a thick coating as described above. Become. When it is assumed that the chemical conversion treatment and the coating are performed after joining, the aluminum alloy and the PPS resin composition obtained at the beginning may be resistant to intrusion of water molecules. That is, at least water resistance is required for the composite immediately after being obtained by injection joining.

  The inventors of the present invention have determined that the penetration of water molecules into the bonded portion can be suppressed by the following NMT and NMT2 improved from NMT. This is because the gap between the aluminum alloy and the PPS resin composition in the composite can be extremely reduced by NMT and NMT2. In addition, as shown in Patent Document 3, the present inventors have confirmed that NMT and NMT2 can suppress the gas passage amount at the joint portion between the aluminum alloy and the PPS resin composition. The present inventors have determined that such a bonding technique with excellent gas sealing properties can also suppress the passage of water molecules.

(NMT)
In the example of NMT shown in FIG. 1, the resin composition 20 penetrates into an ultrafine recess having a diameter of 20 to 50 nm formed on the surface of the aluminum alloy phase 10. The ultrafine recess is covered with an aluminum oxide thin layer 30 having a thickness of 3 nm or more. An aluminum alloy having such a surface structure is inserted into an injection mold, and a molten thermoplastic resin is injected at a high pressure. At this time, a chemical reaction occurs when the thermoplastic resin and the amine compound molecules adsorbed on the aluminum alloy surface are encountered. This chemical reaction suppresses a physical reaction in which the thermoplastic resin is rapidly cooled in contact with an aluminum alloy maintained at a low mold temperature to crystallize and solidify. As a result, the resin is delayed in crystallization and solidification, and in the meantime, enters the ultrafine recesses on the surface of the aluminum alloy, crystallizes and solidifies after entering, and joins the hard aluminum oxide thin layer 30. This anchor effect makes it difficult for the thermoplastic resin to be peeled off from the aluminum alloy surface even when subjected to an external force. That is, the resin molded product formed with the aluminum alloy is firmly bonded. In fact, it has been confirmed that PBT and PPS that can chemically react with an amine compound can be injection-bonded with the aluminum alloy.

  NMT is disclosed in Patent Documents 1 and 2, but an outline thereof will be described. The shaped aluminum alloy part is put into a degreasing tank and degreased. Next, the surface layer is dissolved by immersing in a caustic soda aqueous solution having a concentration of several percent, and the dirt that cannot be removed by the degreasing operation is removed together with the aluminum surface layer. Next, it is immersed in an aqueous nitric acid solution having a concentration of several percent to neutralize and remove sodium ions and the like adhering to the surface in the previous operation. The operation so far is an operation of making the surface of the aluminum alloy part a beautiful surface that is structurally and chemically stable, that is, washing the face before makeup. If the aluminum alloy parts are clean and free from dirt and corrosion, these pretreatment operations can be omitted.

  The important processes in NMT are as follows. In NMT, an aluminum alloy is immersed in an aqueous solution of a water-soluble amine compound under appropriate conditions, and the alloy surface is etched to form ultrafine irregularities with a period of 20 to 80 nm, and the amine compound is chemisorbed simultaneously. The inventors of the present invention conducted an experiment in which each aluminum alloy having different surface treatment conditions was inserted into an injection mold, and an NMT PBT resin or PPS resin was injected and joined. And the conditions which the joining force becomes the maximum and the immersion time in the case of surface treatment becomes 1-2 minutes were searched, and this has been used as an optimal manufacturing method. More specifically, the water-soluble amine compound used for the surface treatment of the aluminum alloy is monohydric hydrazine, and the surface treatment is performed under different conditions (concentration, liquid temperature, immersion time). The bonding strength between the alloy and the thermoplastic resin was measured, and the optimum concentration, liquid temperature, and immersion time were determined.

  For example, an aluminum alloy component is immersed in a hydrazine hydrate solution having a concentration of several percent at 45 to 65 [deg.] C. for 1 minute to several minutes to perform ultra fine etching with an ultra fine uneven surface having a period of 20 to 40 nm. In the immersion treatment in the hydrated hydrazine aqueous solution, the aluminum alloy part is etched into a general corrosion type while emitting hydrogen gas due to the weak basicity of the aqueous solution. When the temperature, concentration, and immersion time are adjusted, the aluminum alloy surface is covered with ultrafine irregularities having a period of 20 to 40 nm. After ultra-fine etching, the aluminum alloy part is thoroughly washed with ion-exchanged water and dried at 50 to 70 ° C., which makes it suitable for injection joining in which chemical adsorption of hydrazine is observed. This is the surface treatment method of “NMT”.

(NMT2)
The inventors of the present invention have improved NMT and developed an injection joining technique with excellent gas sealing performance. This technique is referred to as “NMT2”. In NMT, an aluminum alloy and a resin composition can be bonded with a higher bonding force than ever before. However, the optimum condition from the viewpoint of bonding strength is not always the optimum condition in terms of gas sealing performance. This improvement is to increase the amount of the amine compound to be adsorbed while maintaining the diameter of the ultra fine irregularities at about 20 to 80 nm. That is, the bonding strength is maintained at the maximum level without deforming the shape of the ultra-fine irregularities, and an amine compound (for example, hydrazine) is adsorbed in a larger amount than in the case of NMT, thereby crystallizing and solidifying the thermoplastic resin. It is intended to further delay and increase the degree of penetration into the ultra-fine irregularities.

  The present inventors devised a processing method with such a viewpoint. First, ultra-fine irregularities are created by ultra-fine etching on the aluminum alloy surface under the same conditions as NMT, and then immersed in a more diluted water-soluble amine-based compound aqueous solution at a lower temperature than that used in NMT. A treatment step for increasing the chemical adsorption amount of the compound was provided. As a specific example, first, it is immersed in an aqueous hydrazine solution having a concentration of several percent at 45 to 65 ° C. for 1 to several minutes to form ultrafine recesses having a diameter of 20 to 40 nm on the surface (the same treatment as NMT). In the immersion treatment in the hydrated hydrazine aqueous solution, the aluminum alloy is etched into a general corrosion type while emitting hydrogen gas due to the weak basicity of the aqueous solution. However, if the temperature, concentration, and immersion time are adjusted, the aluminum alloy may exceed 20 to 40 nm period. The entire surface is covered with fine irregularities.

  In NMT2, after the etching process (the same process as NMT), it is immersed for 1 minute to 10 minutes in a 0.05 to 1% aqueous water-soluble amine compound solution (for example, hydrated hydrazine aqueous solution) at 15 to 55 ° C. Then, it is washed with water and further dried at a low temperature of 50 to 70 ° C. The intent is to refrain from etching with a low-concentration water-soluble amine-based compound aqueous solution (for example, a hydrated hydrazine aqueous solution) and advance only the chemical adsorption of the amine-based compound (for example, hydrazine). Moreover, the drying conditions after water washing are 50-70 degreeC and low temperature. This is a result of searching for an optimum temperature for fixing the adsorbed amine compound (for example, hydrazine) as a chemical adsorbent, rather than drying at low temperature to prevent hydroxylation of the aluminum alloy surface. In addition, the surface treatment of the aluminum alloy in NMT is not limited to hydrazine but can be performed with ammonia or a water-soluble amine, and NMT2 is the same as this. In the experimental examples described later, it was confirmed that a surface treatment for NMT2 was possible using a hydrated hydrazine aqueous solution, an alkylamine aqueous solution, and an ethanolamine aqueous solution.

  As a result of conducting an experiment, it was determined that immersion in the aqueous solution of a water-soluble amine compound again could significantly increase the amount of amine compound to be chemisorbed while significantly reducing the etching rate. The result was obtained. The joining force by injection joining did not decrease at all, and the gas sealing performance was greatly improved as compared with NMT. The thermoplastic resin injected on the surface of the aluminum alloy penetrates almost completely to the bottom of the ultrafine recess having a diameter of about 20 to 40 nm, and as shown in FIG. 2, a thin aluminum oxide layer on the surface of the aluminum alloy phase, It seems that there is almost no gap with the plastic resin. This is the reason why the gas sealing performance of NMT2 is significantly improved compared to NMT.

  The reason why the bonding force does not change between the conventional NMT and NMT2 is that the resin part is broken when a strong external force is applied. That is, even when the breakage occurs, the invaded resin remains almost inside the ultra-fine irregularities, and the joining force itself is the same as long as the breakage occurs due to the material destruction of the resin itself. In this way, the injection joining technology using NMT2 applies a specific surface treatment to an aluminum alloy, inserts it into an injection mold, injects an improved thermoplastic resin, releases the mold, and integrates an aluminum alloy / resin molded product. Is exactly the same as “NMT”. However, its gas sealing property is clearly higher than that of NMT.

  The composite obtained by NMT2 is very different from the composite by NMT except for the gas sealing performance. In the breaking force of the composite, all are about 25 to 30 MPa, and these numerical values are the breaking values of the resin molded product. Even when the aluminum alloy material subjected to the surface treatment for NMT and the aluminum alloy material subjected to the surface treatment for NMT2 are observed with an electron microscope, the difference cannot be confirmed. In addition, it is difficult to confirm the difference between NMT and NMT2 even if the joint portion of the composite aluminum alloy piece is sliced to a thickness of 50 nm and observed with a transmission analytical electron microscope. Therefore, a method of measuring a gas sealing property over several days to one week or more after preparing a structure to be described later was adopted.

  As another means, there is a method of analyzing a surface-treated aluminum alloy piece by XPS. However, it is difficult to determine whether a single sample has been subjected to a surface treatment for NMT or a surface treatment for NMT2. XPS is an analytical method that draws out the presence signal of almost all atoms from the sample surface to a depth of several nanometers. Even if it is adsorbed over the entire surface, the absorptance is low in chemical adsorption with only one molecular layer, and nitrogen generated by hydrazine molecules. The atomic signal is very small. Therefore, in order to confirm the presence of nitrogen atoms by XPS, it is not possible to extract a peak from the noise signal, even if it is an NMT-treated product or an NMT2-treated product, unless the irradiation data is accumulated at least five times. On the other hand, repeated X-ray irradiation damages the sample, and chemisorbed hydrazine gradually decreases with repeated irradiation. Therefore, it is not a matter of performing a large number of integrations, and the integration of about 15 times is the limit. In conclusion, it is difficult to use XPS for quantitative analysis of adsorbed hydrazine, and it can be said that it is rather for qualitative analysis. However, if the NMT-treated product and the NMT2-treated product are continuously subjected to XPS analysis on the same day and under the same conditions, the nitrogen atom peak obviously becomes larger.

  In this way, by partially changing the surface treatment method of NMT, the amount of amine compound chemically adsorbed on the surface of the aluminum alloy can be increased. Can invade. As shown in FIG. 2, in NMT 2, the resin penetrates deeper into the ultrafine recess than NMT. As a result, the gas sealing property was significantly improved as compared with NMT. In the experiment shown in Patent Document 3, a state in which a pressure difference of 0.5 MPa is applied to the joint portion between the aluminum alloy and the PPS resin molded product (so that 0.5 MPa helium passes through the joint portion and leaks to the atmospheric pressure side). In such a state, gas sealing performance was realized so that helium leakage could not be confirmed even if left for 7 days.

(Comparison of “NMT” and “NMT2”)
Using the same aluminum alloy and PPS resin, an injection joint by “NMT” and an injection joint by “NMT2” were prepared, and the joint strengths of both were compared. In this case, in both cases, the breaking force is the material breaking value of the resin part, and the breaking force is 25 to 35 MPa, and no difference can be found. The difference between the two finally occurs when the gas tightness test described above is performed. In the injection bonded product by “NMT2”, the injection resin penetrates deeply into the ultrafine irregularities of the aluminum alloy, and the gap distance between the aluminum alloy surface layer and the resin layer is so small that it is difficult for light molecules to pass through.

  The inventors believe that in order to increase the weather resistance of an injection-joined product, the injection-joint product itself needs to have high water resistance and heat-and-moisture resistance, and as much as possible, the clearance between the aluminum alloy surface layer and the resin layer is as much as possible. It is estimated that “NMT2”, which is small and difficult to pass water molecules, is effective. Speaking from the experimental results, the injection-joint using NMT2 was higher in heat and moisture resistance than NMT. However, even with an injection-joined product using NMT, depending on the type of aluminum alloy, sufficiently high moisture and heat resistance was obtained by adding a hydroxylation treatment and an annealing treatment after injection joining. Therefore, it can be said that both NMT and NMT2 are effective.

(Water resistance test)
As a water resistance test of a composite (injected joint), a method in which the composite is tested for several years in an environment where water and oxygen are present is close to the actual use state. For example, after being immersed in water for several years, the composite is taken out and subjected to a tensile breaking test. If the breaking force does not change from before the immersion, it has ideal weather resistance. However, such a test method is time consuming and impractical. Therefore, in the resin industry and the machine manufacturing industry, a wet heat test using a high-temperature and high-humidity tester is adopted, and this test is positioned as an accelerated test for water resistance. The test conditions generally adopted are to place the composite in a high-temperature and high-humidity tester at a temperature of 85 ° C. and a humidity of 85% to measure the heat and humidity resistance for several hundred to several thousand hours. However, when the wet heat test is used as an accelerated test for the water resistance test, it is necessary to measure the bonding strength after placing the composite in room temperature and humidity for a certain period of time after the wet heat test and compare it with the initial value.

  The most frequently used resin in NMT and NMT2 is PPS. PPS is a resin having high heat resistance and low hygroscopicity, and the basic structure of the resin composition does not change in the temperature range of 80 to 100 ° C. in the wet heat test. That is, if it is placed under a moist heat test, the amount of water absorption increases and softens, and the bonding strength decreases. This physical property is suitable for using the wet heat test as an accelerated test for the water resistance test.

(Pot wet heat test)
There is a high possibility that NMT2-treated aluminum alloy and PPS resin injection joints have excellent water resistance. In order to demonstrate this, an injection joined product of A5052 / PPS resin (“SGX120” manufactured by Tosoh Corporation) ”was prepared, and these were put into water and subjected to a water resistance test, and a wet heat test (85 ° C. 85 ° C.) as an acceleration test thereof. % Humidity). However, since this wet heat test requires about 1000 hours, a test method capable of measuring wet heat resistance in a shorter time is desirable as the wet heat test. As a test capable of measuring the heat and humidity resistance in a short time, the present inventors have developed a “pot wet heat test”. In the pot heat and humidity test, water (ion exchange water or the like) is put in an electric pot to 98 ° C., and the injection bonded product is put into this for 20 hours, taken out and dried in hot air at 70 ° C. for 10 hours, and further at room temperature. The air is blown for 10 hours and then broken by a tensile tester, and the breaking force at that time is measured. By this test, it is possible to determine whether or not the injection bonded product has high water resistance in about 40 hours in total.

(Water resistance of injection joints)
In an injection bonded product of an aluminum alloy and a resin using NMT and NMT2, the gap distance between the aluminum alloy and the resin part is on the order of nm. Especially in the case of NMT2, the gap between the aluminum alloy surface layer and the resin is small, and this gap also restricts the passage of water molecules. If the intrusion of water molecules is suppressed, the corrosion of aluminum is also suppressed, and the shape of the ultra fine irregular surface forming the aluminum alloy surface is difficult to change. If so, the change in the bonding force, that is, the decrease of the bonding force over time is small even when placed under high temperature and high humidity. However, the gap between the aluminum alloy and the resin part in the injection-bonded product is not zero (water molecules cannot pass through at all), and a reduction in bonding force is unavoidable when placed under high temperature and high humidity for a long time.

(Improved water resistance)
As a chemical conversion treatment method for an aluminum alloy, there is a boehmite treatment using a hydroxylation reaction of aluminum. The hydroxylation of aluminum proceeds only by placing it in water at 80 to 100 ° C, and also proceeds in water vapor at 100 to 130 ° C. The fact that hydroxylation proceeds in high temperature water indicates that a very low concentration of catalyst (hydroxylation accelerator) can be added to increase the hydroxylation rate. The present inventors paid attention to this hydroxylation treatment as a method for improving water resistance. For example, when the injection-bonded product is immersed in boiling water, an aluminum hydroxide layer (boehmite layer) is formed in the aluminum alloy region other than the bonding range (the region in contact with the resin composition) and is subjected to a chemical conversion treatment. Become. In the vicinity of the boundary line between the aluminum alloy and the resin, the surface layer of the aluminum alloy becomes thicker due to the hydroxylation reaction, so that the gap between the aluminum alloy surface layer and the resin at the boundary portion is reduced, and as shown in FIG. Further, the joining boundary line between the aluminum alloy 51 and the resin composition 53 is covered with the boehmite layer 54 formed on the aluminum alloy surface layer. Thus, the periphery of the joining range 52 is covered with the boehmite layer 54, and as a result, the intrusion of water molecules into the joining range is suppressed.

  By taking a long hydroxylation reaction time, the possibility that the grown aluminum hydroxide fills the gap between the aluminum alloy surface layer and the resin increases. That is, there is a possibility that the penetration of water molecules can be stopped at the outer peripheral line (bonding boundary line) of the bonding range by the hydroxylation treatment. As a result, it was estimated that the hydroxylation reaction within the bonding range was suppressed, and the maintenance of the ultra-fine uneven shape, that is, the bonding force between the aluminum alloy and the resin was maintained. However, it seems that aluminum hydroxide grown by the hydroxylation process may push up the resin part and cause internal strain that causes destruction.

  The present inventors conducted an experiment in which 20 injection-bonded products of A5052 aluminum alloy / PPS resin “SGX120” obtained by NMT2 were subjected to a “pot wet heat test”. This pot moist heat test is an accelerated test of the moist heat test as described above, and at the same time, is a treatment for promoting the hydroxylation reaction. That is, it was tested whether the water resistance could be improved by the “pot wet heat test”. That is, it was poured into pure water of 98 ° C. for 20 hours, taken out, dried with warm air at 70 ° C. for 10 hours, further blown at room temperature for 10 hours, then ruptured by a tensile tester, taken out and taken out at 70 ° C. for 10 hours. The sample was dried with warm air, further blown at room temperature for 10 hours, and then ruptured by a tensile tester. As a result of comparing the breaking force measured at that time with the breaking force of the injection-bonded product of A5052 aluminum alloy / PPS resin “SGX120” before the pot wet heat test, the breaking force of 5 out of 20 was compared. There was no decline at all. It was not possible to overlook the phenomenon in which the breaking force did not decrease at all even in some cases. Therefore, in accordance with the above reasoning, an annealing step is performed in which the injection bonded product is heated at 150 ° C. to 200 ° C. for 20 minutes or more after the hydroxylation reaction. As a result, it was determined that the internal distortion could be eliminated.

(Hydroxylation treatment + annealing treatment)
A number of injection joints of A5052 / “SGX120” were prepared by NMT2, and these were put into a pot containing ion exchange water at 98 ° C. for 20 hours (hydroxylation treatment), taken out, dried at 80 ° C. for 15 minutes, and further 170 ° C. For 1 hour. The bonding strength of the injection bonded product that was subjected to the hydroxylation treatment and the annealing treatment was equivalent to that of the injection bonded material that was not subjected to the hydroxylation treatment. Injected joints that have been subjected to hydroxylation treatment and annealing treatment are not only reduced in bonding strength (breaking force) in the “pot moist heat test” but also subjected to a water resistance test in which they are immersed in pure water at room temperature for 6 months. The bonding force did not decrease at all. Further, the injection bonded product subjected to the hydroxylation treatment and the annealing treatment was put into a high-temperature and high-humidity tester having a temperature of 85 ° C. and a humidity of 85% for 1000 hours, then dried at 70 ° C. for 10 hours, and further placed at room temperature for 10 hours. After cooling, the breaking force was measured with a tensile tester. As a result, the bonding strength was not reduced at all before entering the high-temperature and high-humidity tester.

(Self-repair function)
In the high-temperature and high-humidity test, a large number of injection joints subjected to the hydroxylation treatment and annealing treatment are put into a high-temperature and high-humidity testing machine having a temperature of 85 ° C. and a humidity of 85%. After 200 hours, 400 hours, and 600 hours After 800 hours and 1000 hours, a predetermined number of injection joints were taken out and subjected to an experiment on a tensile tester. And about the injection joined thing taken out after 1000-hour progress, the result that the joining force was equivalent compared with the injection joined thing before throwing into a high-temperature, high-humidity tester was obtained. However, with regard to the injection-joined product taken out after 200 hours, a plurality of those having a reduced breaking force were confirmed. On the other hand, regarding the injection-joined product taken out after 400 hours, it was not confirmed that the breaking force was reduced.

  This is presumably because the wet heat test itself produced the effect of filling the gap between the aluminum alloy surface layer and the resin layer. In other words, even after the hydroxylation treatment and annealing treatment, there are still gaps between the aluminum alloy surface layer and the resin layer, where there was still room for water molecules to enter, but in a high temperature and high humidity environment. It is considered that the hydroxylation reaction was promoted by being placed at (temperature 85 ° C., humidity 85%) for a long time, and the remaining gap was blocked by the boehmite layer. Therefore, the present inventors replaced the condition of immersing in the ion-exchanged water at 98 ° C. for 20 hours when performing a hydroxylation treatment on the injection-joined product, and the aqueous solution (98 ° C.) containing several hundred PPM of nickel acetate. The conditions were soaked for 20 hours or soaked in an aqueous solution (98 ° C.) containing several thousand PPM for several tens of minutes. A large number of injection bonded products obtained by this treatment subjected to hydroxylation treatment and annealing treatment were put into a high-temperature and high-humidity testing machine with a temperature of 85 ° C. and a humidity of 85%, taken out after 200 hours, and subjected to a tensile testing machine to measure the joining force. As a result, none of the bonding strength was reduced. That is, it was confirmed that the periphery of the joining range can be sealed with a boehmite layer by performing strong hydroxylation treatment.

  From these results, it is expected that the hydroxylation treatment of the aluminum alloy surface layer is promoted even in an actual environment (in a high-temperature and high-humidity environment), and this prevents a decrease in bonding force. That is, it suggests the possibility that the injection-bonded product exhibits a self-repair function when placed in a high-temperature and high-humidity environment.

  Regarding the above-described hydroxylation treatment and annealing treatment, the effect could be confirmed by an experiment using A5052 aluminum alloy. On the other hand, since the reaction rate of the hydroxylation reaction varies depending on the type of aluminum alloy, it is necessary to adjust the conditions of the hydroxylation reaction for each type. As described above, since these can promote the hydroxylation reaction by using an aqueous solution other than pure water in the hydroxylation reaction, for example, nickel acetate or other hydroxylation catalyst, an aqueous solution for each aluminum alloy species. It is advisable to adjust the type and concentration of the liquid as appropriate.

  The composite of the aluminum alloy and the PPS resin according to the present invention is a molded product of the aluminum alloy and the PPS resin, and the bonding strength does not decrease even if the composite is placed in a high temperature and high humidity environment for a long time. It is characterized by. In the present invention, by utilizing the reactivity of aluminum with water molecules and forming a boehmite layer on the surface of the aluminum alloy, it is possible to suppress the penetration of water molecules into the joint and obtain a composite with excellent water resistance. I was able to. By applying a weather resistant paint to such a composite, a weather resistant member can be obtained.

FIG. 1 is a schematic cross-sectional view of an injection bonded product obtained by NMT. FIG. 2 is a schematic cross-sectional view of an injection bonded product obtained by NMT2. FIG. 3 is a schematic cross-sectional view of an injection bonded product that has been subjected to hydroxylation. FIG. 4 is a perspective view of an injection bonded product used for a tensile test. FIG. 5 is a perspective view of an injection bonded article used for a tensile test. FIG. 6 is a schematic diagram showing a fracture shape when the injection-joined material fractures in the tensile test. FIG. 7 shows the surface of the aluminum alloy when it is ground with abrasive paper and provided with scratches. FIG. 8 is a view showing an aluminum alloy surface when a groove is formed by machining with an NC milling machine.

[PPS resin composition]
Several types of PPS resins for NMT are currently commercially available. As described above, in NMT2, a resin composition used in NMT can be used. That is, a resin composition containing PBT, PPS, polyamide resin, or the like can be used. Here, a PPS resin will be described as an example. Several types of PPS resins for NMT are currently commercially available. “SGX120 (manufactured by Tosoh Corporation)” is one of NMT PPS resins. This can also be used in NMT2. Details of the resin composition are described in Patent Documents 4 and 5, and an outline thereof is described. The PPS resin composition for NMT is a composition in which 70 to 97% of the resin component is PPS and 30 to 3% is a modified polyolefin resin. In addition to this, it is preferable that a component that promotes compatibilization of the two is contained. In addition to the resin component, fillers and others are included.

  The modified polyolefin resin is preferably a maleic anhydride-modified ethylene copolymer, a glycidyl methacrylate-modified ethylene copolymer, a glycidyl ether-modified ethylene copolymer, an ethylene alkyl acrylate copolymer, or the like. Examples of the maleic anhydride-modified ethylene copolymer include maleic anhydride graft-modified ethylene polymer, maleic anhydride-ethylene copolymer, ethylene-acrylic acid ester-maleic anhydride terpolymer. Among them, an ethylene-acrylic acid ester-maleic anhydride terpolymer is preferable because a particularly excellent composite is obtained, and the ethylene-acrylic acid ester-maleic anhydride terpolymer is preferable. Specific examples of these include “Bondaine (manufactured by Arkema)” and the like.

  Examples of the glycidyl methacrylate-modified ethylene-based copolymer include glycidyl methacrylate graft-modified ethylene polymer and glycidyl methacrylate-ethylene copolymer. Among them, particularly excellent composites are obtained, and therefore glycidyl methacrylate-ethylene copolymer. A polymer is preferred, and specific examples of the glycidyl methacrylate-ethylene copolymer include “Bond First” (manufactured by Sumitomo Chemical Co., Ltd.).

  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 “rotoryl ( Arkema) ”and the like. The ethylene alkyl acrylate copolymer includes an ethylene alkyl acrylate copolymer, an ethylene alkyl methacrylate copolymer, and the like, which can be preferably used.

  When blended with 0.1 to 6 parts by weight of a polyfunctional isocyanate compound and / or 1 to 25 parts by weight of an epoxy resin with respect to 100 parts by weight of the resin, mixing with an extruder (mixing at a molecular level) is good. It is preferable. As the polyfunctional isocyanate compound, commercially available non-block type and block type compounds 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. The polyfunctional block type isocyanate compound has two or more isocyanate groups in the molecule, and the isocyanate group is reacted with a volatile active hydrogen compound so as to be inactive at room temperature. 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. Examples of the polyfunctional block type isocyanate include “Takenate (manufactured by Mitsui Takeda Chemical Co.)”.

  As the epoxy resin, an epoxy resin generally known as a bisphenol A type, a cresol novolak type or the like can be used. As the bisphenol A type epoxy resin, for example, “Epicoat (manufactured by Japan Epoxy Resin Co., Ltd.)” or the like can be used. Examples of the cresol novolac type epoxy resin include “Epiclon (manufactured by Dainippon Ink and Chemicals)” and the like.

  Examples of fillers include reinforcing fibers and powder fillers. Examples of reinforcing fibers include glass fibers, carbon fibers, and aramid fibers. Specific examples of glass fibers include an average fiber diameter of 6 to 14 μm. Chopped strands and the like. Examples of the powder filler include calcium carbonate, mica, glass flake, glass balloon, magnesium carbonate, silica, talc, clay, pulverized carbon fiber and aramid fiber. The filler is preferably treated with a silane coupling agent or a titanate coupling agent. The filler content is 0-60% in the finished resin composition, preferably 20-40%.

[Injection joining process]
(Implementation of injection joining)
An aluminum alloy material treated with NMT or NMT2 is inserted into an injection mold, and the PPS resin is injected. The injection conditions are the same as the injection molding conditions of ordinary PPS resin, but the mold temperature is set to 120 to 150 ° C., which is slightly higher than normal, and the injection speed and injection pressure are slightly higher than the setting conditions at the time of normal PPS injection molding. It is preferable to make it higher. A common purpose of NMT and NMT2 is to generate a strong bonding force by pushing a resin into the ultrafine recesses of the ultrafine uneven surface of the aluminum alloy material. Therefore, gas accumulation and gas burning are strictly prohibited, and degassing is indispensable for the mold. When degassing, thin burrs are likely to occur, but in the case of NMT2, it is preferable to inject firmly to such an extent that thin burrs are produced. In short, injection molding conditions should not be determined solely for the purpose of obtaining a molded article with a beautiful appearance. The purpose is to make it firmly injection-bonded, and if thin burr formation hinders it, it should be removed in a later process.

(Annealing)
After releasing the injection bonded article from the injection molding machine, it is preferable to place it at a temperature around 170 ° C. for about 1 hour within 24 hours. This is a process necessary for allowing the aluminum alloy and the molded PPS resin composition to maintain a strong bonding force for a long period of time. In injection joining for the purpose of securing a strong joining force, the mold temperature is 110 to 160 ° C. Therefore, when the mold is released from the mold and allowed to cool, the metal alloy part is cooled by about 100 ° C. and the coefficient of linear expansion is increased. Shrink. One resin part shrinks according to the molding shrinkage rate. The shrinkage rate itself differs between a metal alloy (here, an aluminum alloy) and a resin (here, a PPS resin), and the shrinking speed (change in shrinkage with time) also differs.

  While the injection bonded product is released from the molding machine and allowed to cool to room temperature, the aluminum alloy side tries to shrink by 0.2 to 0.3%, but after the PPS resin composition is released. Attempts to shrink the mold about 0.3 to 0.8% over about 24 hours. The reason why the numerical range on the resin side is large is that the molding shrinkage varies depending on the flow direction of the resin, and it takes 24 hours because crystallization continues even at room temperature. In addition, the shrinkage rate of the resin molded product due to crystallization is initially high and decreases with time. In any case, the shrinkage of the metal and the resin is different, but the two are strongly bonded. At this time, in the vicinity of the joint surface, both the aluminum alloy and the resin part are subjected to interference from the other side, and internal strain occurs. An annealing process was performed for the purpose of eliminating this internal strain.

  The PPS resin becomes soft at around 170 ° C., and the entanglement between the polymers is loosened. Although it is not free at all, a slight movement becomes possible and internal distortion is eliminated. In addition, since most of the crystallization of the resin part has already been completed before annealing, the shrinkage of the resin part when it is allowed to cool after the annealing is not according to the mold shrinkage rate, but according to the normal linear expansion rate. It will be. Therefore, since the difference in shrinkage rate between the aluminum alloy and the resin is reduced, the internal strain remaining after cooling is significantly reduced from that before annealing. For these reasons, annealing after injection bonding is a process necessary to eliminate internal strain.

(Shape of injection joint)
The inventors of the present invention made an injection bonded product having the shape shown in FIG. 4 and the shape shown in FIG. 4 is a plate-like product in which the shape of the aluminum alloy 51 is 45 mm × 18 mm × 1.6 mm thick, and the resin molded product 53 is a plate-like product of 45 mm × 10 mm × thickness 3 mm. The area of the joining range 52 of both members is 10 mm × 5 mm = 0.5 cm ² . 5 is a plate-like product in which the shape of the aluminum alloy 51 is 30 mm × 30 mm × thickness 2 mm, and the resin molded product 53 is a plate-like product of 45 mm × 10 mm × thickness 3 mm. The area of the joining range 52 of both members is 10 mm × 5 mm = 0.5 cm ² .

  These injection joints differ only in the thickness and shape of the aluminum alloy pieces, but this results in different wet heat test results. For both the pot moist heat test and the test with the high temperature and high humidity tester at 85 ° C. and 85% humidity, the bonding strength of the injection bonded product shown in FIG. 5 is determined from the bonding strength before being placed in the high temperature and high humidity environment. Declined. On the other hand, regarding the room temperature immersion test (period of 6 months), the bonding strength of both the injection-bonded members in FIGS. 4 and 5 did not decrease.

  Comparing the injection joints of FIG. 4 and FIG. 5, the only difference is the shape of the aluminum alloy piece. In particular, the injection joint of FIG. 5 is not only wide, but also has a thickness of 2 mm. It is considered that the wet heat durability of the bonding force was lowered by the above. In general, in order to maintain the bonding force of composites made of different materials for a long period of time, it is necessary that both are soft members or at least one of them is a soft member. When both are strong members, internal strain occurs at the joint surface between members having different linear expansion coefficient and moisture content expansion coefficient, and if there is no flexibility to eliminate the internal strain, peeling occurs from the outer periphery of the joint part and breaks. To.

  As shown in FIG. 5, the aluminum alloy part is a plate-like material, and the bending strength is strong when the thickness is large. In order to maintain the bonding force for a long period of time, there is no choice but to reduce the internal strain by reducing the bonding area with the resin part or to reduce the bending strength by reducing the thickness of the resin part. The injection-bonded product is required to have a bonding force that does not decrease through a temperature impact test of at least −50 ° C./+100° C. Furthermore, it is required for the injection-bonded product that the bonding force does not decrease over a long period (one month or more) in an environment of a temperature of about 40 ° C. and a humidity of about 60%. If there is no decrease in bonding force in such an experiment, the shape of the bonding range will not change, and the water resistance should be maintained.

(Fracture shape of aluminum alloy piece)
The injection bonded product obtained by NMT or NMT2 was broken by a tensile tester as shown in FIG. 6, and the measured value at the time of breaking was measured as the breaking force. However, since the joining by NMT and NMT2 is extremely high in strength, when the injection joint is pulled in the direction shown in FIG. 6B, the joint surface portion is stretched and both the metal and the resin are bent and deformed. As a result, resin breakage may occur before the joint portion shears and breaks (FIG. 6C). The figure shown on the left of FIG.6 (c) shows the fracture | rupture shape when a shear fracture | rupture has arisen, and the figure shown on the right has shown the fracture | rupture shape when a resin broken fracture | rupture has arisen. In the case of resin breakage, it is clear that the measured breaking force is lower than the true bonding force.

  In the case of the injection bonded product shown in FIG. 4 (a thickness of the aluminum alloy piece 1.6 mm), the breaking force is 25 to 27 MPa, and the breaking shape is a resin folding type. On the other hand, in the injection-bonded product (thickness of aluminum alloy piece 2.0 mm) shown in FIG. 5, the metal side is not easily bent and deformed at the time of tensile break, the break force is 29 to 31 MPa, and the break shape is a resin fold type and a shear type. Mixed. Therefore, in addition to the measured breaking force, the joining state is determined by observing the joining portion. In the case of resin breakage, the resin part remaining in the aluminum alloy part was forcibly peeled off with a nipper or the like, and the joining part was observed. Even if there is a small amount of resin remaining, the bonding state is "good" if it adheres to the entire surface of the joint, but if there is resin residue only in the center but there is no resin adhesion in the periphery, the bonding state is "bad" I decided.

[Method of improving bonding strength]
As described above, if the expansion coefficient and the hygroscopic expansion coefficient of both members of the injection bonded product are different, an internal strain (stress) is always generated in the bonding range. This internal strain not only affects the longitudinal elastic modulus but also actually affects the transverse elastic modulus and bulk elastic modulus. In short, the joint surface must be considered not as two-dimensional (surface) but as three-dimensional (thick layer). Internal strain occurs in this layer, and when an external force is applied, the sum of the internal strain and the external force exceeds the material destruction value, resulting in destruction. If this layer could be thickened to increase the volume, it was thought that internal strain could be dispersed in that large volume. In short, this is an internal strain relaxation method by thickening the bonding-related layer.

  Here, in NMT and NMT2, strong bonding is achieved by forming ultrafine irregularities with a period of 20 to 80 nm on the surface of the aluminum alloy and causing the injected resin to bite into the ultrafine irregularities. In other words, the part involved in the bonding is a thin layer having a thickness of about 100 nm, and this thin layer relieves strain between the metal phase and the resin phase. By adopting a double concavo-convex structure in which concavo-convex with a larger period (several μm to several mm) is added in addition to ultra-fine concavo-convex with a period of 20 to 80 nm, it is considered that larger strain can be relaxed. . Specifically, on the part to be bonded to the resin on the surface of the aluminum alloy before injection bonding, irregularities with a period of 20 to 80 nm and irregularities with a period of several μm to several mm (RSm is in the range of 2 μm to 2 mm, and Rz is 1 μm. (Unevenness in the range of ˜1 mm) coexist and the resin is injected into the part. Thereby, even when the thick aluminum alloy piece shown in FIG. 5 was used, the wet heat resistance was not lowered, and it was possible to prevent the joining force from being lowered due to the difference in strength of the aluminum alloy pieces.

  Decide the shape of the injection joint and design the mold, make a prototype of the injection joint using NMT or NMT2, perform a temperature shock test of about -50 ° C / + 100 ° C, temperature 60 ° C humidity 60% Perform a high-humidity test to the extent that there is a decrease in bonding strength. When the durability of the bonding force is reduced by these tests, as described above, the surface of the aluminum alloy is made to have high temperature by performing injection bonding by causing unevenness with a period of 20 to 80 nm and unevenness with a period of several μm to several mm to coexist. It is possible to prevent a decrease in bonding strength in a high humidity environment. It is also possible to maintain the bonding force by reducing the thickness of the resin part, that is, reducing the strength of one of the injection-bonded articles.

(Roughening method of aluminum alloy)
As described above, it is possible to maintain the bonding force by forming irregularities with a period of several μm to several mm for an aluminum alloy subjected to surface treatment for NMT or NMT2, but in particular, several tens of μm to It is preferable to form irregularities with a period of several hundred μm. Specifically, the surface of the aluminum alloy surface to be joined with the resin is roughened using rough abrasive paper (No. 40-240 abrasive paper defined in JIS R6252). The line scar formed by polishing has a width of 0.05 to 0.5 mm and a depth of about 0.02 to 0.5 mm. Moreover, you may make it provide a some groove | channel in the said location using press work or NC milling machine. For example, a plurality of grooves having a width of 0.5 to 2.0 mm and a depth of 0.2 to 1.0 mm may be provided at intervals of 0.5 to 2.0 mm.

[Water resistance of injection joints]
If the injection-bonded product has good heat-and-moisture resistance, the water resistance is good. However, just because the heat-and-moisture resistance is bad, it does not mean that the water-resistance is bad. In fact, the bonding strength of the injection bonded product of A5052 aluminum alloy and PBT resin or polyamide resin obtained by NMT2 does not decrease at all even if it is placed in pure water for 3 months or more and subjected to a tensile test. Therefore, the water resistance is good. On the other hand, when a wet heat test was performed for several days in a high temperature and high humidity environment, the bonding strength dropped sharply. This is because PBT and polyamide do not change in quality when placed at room temperature or simply in a high temperature environment, and are heat-resistant resins. However, hydrolysis occurs when placed in a high temperature and high humidity environment.

  That is, the conditions set in the wet heat test do not exist in the actual environment and are excessive. In an outdoor environment or an in-vehicle environment, any material that can withstand a temperature shock of −50 ° C./+100° C. may be used. PBT resins and polyamide resins are also frequently used in automobile parts.

[Hydroxylation treatment and annealing treatment]
As described above, it is possible to maintain the bonding force in a high-temperature and high-humidity environment by performing a hydroxylation treatment and an annealing treatment on the injection-bonded product. A commercially available electric hot water pot can be used for this. Ion exchange water or ion exchange water containing 100 to 10000 PPM of nickel acetate or the like as a catalyst for hydroxylation reaction is put into an electric hot water pot, and the temperature is raised to 98 ° C., and then the injection bonded article is introduced. The injection bonded product was immersed in ion exchange water in a pot for 10 minutes to 50 hours and then taken out, and after simple drying or wiping off moisture on the surface, it was placed in a hot air dryer and annealed at 170 ° C. for 1 hour. Further, water vapor may be used instead of water. Any method that can form a boehmite layer may be used. On the other hand, regarding annealing, the range of 160-180 degreeC is preferable.

  After performing the hydroxylation treatment and the annealing treatment, it is preferable to confirm once whether or not the joining strength of the injection-bonded product has decreased. Normally, the bonding force is not reduced by these treatments. However, if it is lowered, it is considered that the surface treatment of NMT or NMT2 is not properly performed, or a problem has occurred in the injection bonding process. If the surface treatment of NMT or NMT2 is appropriately performed, the bonding force does not decrease even if some problems occur in the injection joining process, but if problems occur in the injection joining process, it becomes difficult to obtain water resistance. .

(Pot wet heat test)
The injection-bonded product that has been subjected to hydroxylation treatment and annealing treatment is a component member having sufficient water resistance and moisture and heat resistance, and becomes a member having weather resistance by painting. Here, it is preferable to perform a “pot wet heat test” as an inspection before coating. The “pot moist heat test” is a method in which an injection bonded product subjected to hydroxylation treatment and annealing treatment is immersed in ion exchange water at 98 ° C. for about 20 hours, taken out, dried at 70 ° C. for 10 hours, and then at room temperature for 10 hours. After drying, this is a test for measuring the bonding force by using a tensile tester.

[Weatherability]
Once an injection-bonded product that has been subjected to a hydroxylation treatment and an annealing treatment is obtained, it is possible to obtain a component with excellent weather resistance by adding a coating thereto. Further, it is considered that higher weather resistance can be obtained by applying a chemical conversion treatment such as a chromate treatment to the injection bonded product. It is the chromate type chemical conversion treatment that many aluminum plate and extrusion material manufacturers use. In addition, boehmite treatment (hydration treatment) is frequently used in manufacturers that manufacture aluminum products that are close to the final product by machining using unprocessed plate materials, extruded materials, block materials, and the like. . In the experimental example to be described later, the injection-bonded product is subjected to a hydroxylation treatment and an annealing treatment, which is substantially a boehmite treatment, and therefore it is not necessary to perform a chemical conversion treatment again thereafter. High weather resistance can be obtained by coating the injection-bonded product that has been subjected to hydroxylation and annealing. It should be noted that additional chemical conversion treatment is not applied to the injection bonded product that has been subjected to hydroxylation treatment and annealing treatment because it does not affect the bonding force even if it is immersed in chromate treatment liquid or non-chromate treatment liquid. May be. In addition, when chemical conversion treatment such as chromate type chemical conversion is performed, one or more element signals selected from chromium, zirconium, manganese, and silicon are detected when the aluminum alloy surface is subjected to elemental analysis by XPS. The These elements are deposits generated by the chemical conversion treatment.

(paint)
The PPS resin is a heat-resistant resin, and from the viewpoint of ensuring adhesion with the PPS resin, it is a coating for metal baking, that is, a one-component, thermosetting with a curing temperature of 120 ° C or higher, preferably 150 ° C or higher. It is preferable to use a mold paint. Various paints are marketed by paint manufacturers for coating aluminum alloy sheets, aluminum alloy intermediate members (pipe, bar, other shaped extrusion materials, etc.), sash members, etc., so you can choose from these. In general, an epoxy-based paint having good adhesion to a metal oxide is suitable for undercoating, and a polyester-based paint, polyurethane-based paint, or fluororesin paint that is resistant to sunlight is suitable for overcoating.

  In the experimental example to be described later, two layers of the injection-bonded product were applied. The base coating was an epoxy one-component baking coating, and the top coating was a fluororesin baking coating. It is preferable to use a high-temperature curing type one-component epoxy paint having excellent adhesion to the chemical conversion film and good adhesion to PPS for the base. However, since the epoxy paint is weak against sunlight, a two-layer paint using a fluorine resin paint, a polyester paint, or a urethane paint resistant to sunlight as the top coat is preferable to the one-coat paint.

  Further, in the experimental example described later, two cycles (48 hours) are performed on both of the injection-joint that has been coated with two layers without any additional chromate treatment and the injection-joint with two layers that have been subjected to additional chromate treatment. The salt spray test was conducted. In all cases, no rust was generated, and at least the additional chromate treatment did not reduce the bonding force.

[Experimental example]
Hereinafter, experimental examples will be described. The equipment used for the experiment is shown below.
(1) Electron microscope observation An electron microscope was used for observation of the aluminum alloy material surface. A scanning (SEM) electron microscope “JSM-6700F” (Tokyo, Japan, manufactured by JEOL Ltd.) was used and observed at an acceleration voltage of 1 to 10 kV.
(2) XPS observation XPS (X-ray photoelectron spectroscopic analysis) was performed to observe the element species present on the surface of the aluminum alloy material. XPS “ESCA-3400” (manufactured by Shimadzu Corporation) was used for this test.
(3) Measurement of the bonding strength of the composite As a measurement of the bonding strength of the composite, tensile stress is measured. Specifically, the composite was pulled with a tensile tester to apply a shearing force, and the breaking force when the composite broke was measured. As the tensile tester, “AG-10kNX” (manufactured by Shimadzu Corporation) was used, and the tensile speed was 10 mm / min.
(4) High temperature and high humidity test The composite was measured every 200 hours to 2000 hours in an environment having a temperature of 85 ° C and a humidity of 85% or less, and the transition of the bonding force was measured. A high-temperature and high-humidity tester “60 liter small environmental tester” (manufactured by Espec Corp.) was used for this test.
(5) Temperature shock cycle test The composite was subjected to a temperature shock of −40 ° C./+100° C. The residence time at the lowest temperature and the highest temperature was 30 minutes each, the transfer time between both temperatures was 5 minutes each, and one cycle was 1 hour 10 minutes in total. The composite was tested for 1000 cycles of temperature shock. A “small temperature impact tester” (manufactured by Espec Corp.) was used for this test.
(6) Salt spray test At 35 ° C., the complex was sprayed with neutral 5% strength salt water for 8 hours, and the spray was stopped for 16 hours and the cycle (24 hours) was reported for 2 cycles (48 hours). ) Repeated. A salt spray tester “STP-200 (manufactured by Suga Test Instruments Co., Ltd.)” was used for this test.

[Experiment 1] Surface treatment of A5052 piece (NMT2)
An A5052 aluminum alloy sheet having a thickness of 1.6 mm was obtained and cut into 45 mm × 18 mm to produce a large number of A5052 pieces. A hole was made in the end of each A5052 piece, and a PVC-coated copper wire was passed through the hole, so that a large number of A5052 pieces were suspended from the copper wire so that a dipping process could be performed simultaneously. Surface treatment for NMT2 was performed on these A5052 pieces. First, an aqueous solution (liquid temperature 60 ° C.) containing 7.5% of an aluminum degreasing agent “NE-6” (manufactured by Meltex) was prepared in a tank, and this was used as a degreasing tank. A5052 piece was immersed in the degreasing layer for 5 minutes and washed with tap water (Ota City, Gunma Prefecture). Next, an aqueous solution containing 1% hydrochloric acid (liquid temperature 40 ° C.) was prepared in another tank, and this was used as a preliminary pickling tank. The A5052 piece was immersed in this preliminary pickling tank for 1 minute and washed with ion-exchanged water. Next, an aqueous solution (liquid temperature 40 ° C.) containing 1.5% of caustic soda was prepared in another tank, and this was used as an etching tank. The A5052 piece was immersed in this etching tank for 1 minute and washed with ion-exchanged water. Next, a 3% nitric acid aqueous solution (liquid temperature 40 ° C.) was prepared in another tank, and this was used as a neutralization tank. The A5052 piece was immersed in this neutralization tank for 1 minute and washed with ion-exchanged water. Next, an aqueous solution (liquid temperature 60 ° C.) containing 3.5% hydrated hydrazine was prepared in another tank, and this was used as the NMT first processing tank. The A5052 piece was immersed in this NMT first treatment tank for 1 minute and washed with ion-exchanged water. Next, an aqueous solution (liquid temperature 33 ° C.) containing 0.5% of hydrated hydrazine was prepared in another tank, and this was used as the NMT second processing tank. The A5052 piece was immersed in this NMT second treatment tank for 3 minutes and washed with ion-exchanged water. Next, the A5052 piece was placed in a hot air dryer at 67 ° C. for 15 minutes and dried. The A5052 pieces thus surface-treated were overlapped and wrapped with aluminum foil, further sealed in a plastic bag and stored.

  As a result of observing the surface of the A5052 piece subjected to the above surface treatment with an electron microscope, the surface was covered with innumerable ultrafine recesses, and the diameter of the recesses was 20 to 40 nm. Moreover, the presence of nitrogen could be confirmed by surface observation by XPS.

Experimental Example 2 PPS Resin A commercially available PPS resin “SGX120” (manufactured by Tosoh Corporation) was used. The “SGX120” pellets were taken on a stainless steel flat plate every several kg and placed in a hot air dryer set at 150 ° C. for 2 hours or more to dry.

[Experiment 3] Injection joining (A5052 / SGX120)
An A5052 piece subjected to the surface treatment of Experimental Example 1 was inserted into an injection mold having a mold temperature of 145 ° C., and “SGX120” of Experimental Example 2 was injected on the surface thereof. The injection temperature was 300 ° C. In this way, a large number of A5052 / SGX120 injection joints were obtained. The resin piece made of SG120 is a rectangular parallelepiped having a thickness of 45 mm × 10 mm × 5 mm, and the bonding area with the A5052 piece is 10 mm × 5 mm = 0.5 cm ² . The injection-bonded product was annealed for 1 hour in a hot air dryer set at 170 ° C. and allowed to cool. As a result of measuring the joining force of the three injection joints obtained in this manner by using a tensile tester, the breaking force was an average of 26.1 MPa, and all were resin fractures. The resin remaining at the location that was in the joining range was peeled off with a nipper and observed. There was little resin remaining in the bonding range, and it adhered to the entire bonding range, and the bonding state was “good”.

[Experimental Example 4] Hydroxide treatment and annealing treatment Ion exchange water was put into a commercially available hot water pot (manufactured by Tiger Thermos) for about 6 minutes, set at 98 ° C., and injection joining obtained in Experimental Example 3 after the temperature rise. The product was put in and left for 20 hours, and then removed from the pot (hydroxylation treatment). Thereafter, the injection bonded product was put in a hot air dryer and annealed at 80 ° C. for 30 minutes and then at 170 ° C. for 1 hour. After allowing to cool, the three bonded joints were each subjected to a tensile tester and the bonding force was measured. As a result, the average breaking force was 25.8 MPa, and all were resin fractures. It was confirmed that all of the joining states were “good” and substantially unchanged from the joining force in Experimental Example 3.

[Experimental Example 5] High-temperature and high-humidity test Using the injection bonded product subjected to the hydroxylation treatment and annealing treatment of Experimental Example 4, a high-temperature and high-humidity test was conducted. 16 injection joints were put into a high-temperature and high-humidity tester with a temperature of 85 ° C. and a humidity of 85%, and two pieces were taken out after 200 hours, 400 hours, 750 hours, 1000 hours, and 2000 hours, respectively. The injection-bonded product was dried at 70 ° C. for 10 hours and then cooled at room temperature for 10 hours. Table 1 shows the results of measuring the joining force by applying the injection-joined product after cooling to a tensile tester. From the results shown in Table 1, it can be confirmed that the bonding strength is not substantially reduced even when the injection bonded article is placed in a high temperature and high humidity environment for 2000 hours. In addition, all 10 bonding states were “good”.

[Experimental Example 6] Surface treatment of A5052 piece (NMT2)
An A5052 aluminum alloy sheet having a thickness of 2 mm was obtained and cut into 30 mm × 30 mm to prepare 60 A5052 pieces. 30 of them were subjected to the same surface treatment as in Experimental Example 1. The other 30 pieces were subjected to the same surface treatment as in Experimental Example 1 after roughening the portion that would be in the bonding range (10 mm × 5 mm) with the PPS resin. For the roughening, No. 120 abrasive paper defined in JIS R6252 was used, and the abrasive paper was pressed against the above-mentioned place and polished several times. As shown in FIG. 7, the scratch 55 generated on the A5052 piece 51 at that time was linear.

[Experimental Example 7] Injection joining (A5052 / SGX120)
Insert the non-scratched A5052 piece (with only the surface treatment of NMT2) obtained in Experimental Example 6 into the injection mold at a mold temperature of 140 ° C. 2 “SGX120” was injected. The injection temperature was 300 ° C. In this way, 30 A5052 / SG120 injection bonded articles were obtained. The resin piece made of SG120 is a rectangular parallelepiped having a thickness of 45 mm × 10 mm × 5 mm, and the bonding area with the A5052 piece is 10 mm × 5 mm = 0.5 cm ² . The injection-bonded product was annealed for 1 hour in a hot air dryer set at 170 ° C. and allowed to cool. Further, for the A5052 pieces with scratches obtained by polishing in Experimental Example 6 (those subjected to surface treatment and polishing treatment of NMT2), 30 injection joints with “SGX120” were obtained in the same manner. . As a result of measuring the joining force by applying a total of 6 injection joints obtained in this way to a tensile tester, the breaking force was an average of 31.3 MPa, and all were shear fractures. There was no difference in the rupture force between the injection joint with no scratch and the injection joint with the scratch.

[Experimental Example 8] Hydroxication Treatment and Annealing Treatment A total of 60 injection joints obtained in Experimental Example 7 that were not subjected to polishing treatment and 30 injection joints that were subjected to polishing treatment were combined with Experimental Example 4 and In the same manner, hydroxylation treatment and annealing treatment were performed. As a result of measuring the joining force of three injection joints not subjected to polishing treatment (without scratches) using a tensile tester, the breaking force was 30.2 MPa. In addition, as a result of measuring the joining force by applying three polishing joints (with scratches) subjected to polishing treatment to a tensile tester, the breaking force was 31.1 MPa. In either case, shear fracture and resin fracture were mixed. A small amount of resin adhered to all the locations where shear fracture occurred, and the bonding state was all “good”. As a result of observing the surface by peeling off the remaining resin from the location where the breakage of the broken resin mold occurred, the bonded state was all “good”. From these measurement results and observation results, it was confirmed that the bonding force was not substantially changed by the hydroxylation treatment and the annealing treatment.

[Experimental Example 9] Pot Wet Heat Test (large A5052 NMT2 injection-bonded product)
A pot moist heat test was conducted using three each of the two types of injection joints (no polishing treatment and with polishing treatment) subjected to the hydroxylation treatment and annealing treatment of Experimental Example 8. Ion exchange water was put in a commercially available electric pot up to the sixth minute and set at 98 ° C. Three pieces of each of the two types of injection joints were put into ion-exchanged water at 98 ° C., and all were taken out after 20 hours. The taken-out injection bonded product was put into a hot air dryer, dried at 70 ° C. for 10 hours, and further placed at room temperature for 10 hours, and then subjected to a tensile fracture test to measure the bonding force. The breaking force was an average of 18.4 MPa for the injection-joined product without polishing treatment, and an average of 30.7 MPa for the injection-joined product with polishing treatment. The joining force was maintained in the injection-bonded product in which scratches were provided by the polishing process, but the joining force was reduced in the injection-joined product having no scratch.

[Experimental Example 10] High-temperature and high-humidity test A high-temperature and high-humidity test was conducted using the injection-bonded product subjected to the hydroxylation treatment and annealing treatment of Experimental Example 8. Two types (no polishing treatment and with polishing treatment) of 10 injection joints were put into a high-temperature and high-humidity tester with a temperature of 85 ° C. and a humidity of 85%, after 200 hours, 400 hours, 750 hours, and 1000 hours. Thereafter, two pieces were taken out after 2000 hours, and the taken out injection-joined articles were dried at 70 ° C. for 10 hours and then cooled at room temperature for 10 hours. Table 2 shows the results of measuring the joining force of the injection-joined product after cooling using a tensile tester. It can be confirmed that the injection joint that has been scratched by polishing maintains a high joining force even in a high temperature and high humidity environment for a long time. That is, for the injection bonded product (with scratches) that showed good results in the pot moist heat test of Experimental Example 9, a high bonding force was maintained even in the test using the high temperature and high humidity tester. On the other hand, regarding the injection-bonded product (without scratches) in which the bonding strength decreased in the pot wet heat test of Experimental Example 9, the bonding strength decreased with time even in the high-temperature and high-humidity tester.

[Experimental Example 11] Water Resistance Test A water resistance test was performed using the injection-bonded product subjected to the hydroxylation treatment and the annealing treatment of Experiment Example 8. Two kinds of injection joints (no polishing treatment and with polishing treatment) 8 pieces each are put into a sealable glass bottle with a capacity of 600 cc, 400 cc of ion exchange water is put in this glass bottle and sealed with a lid, and it is a bright place where sunlight does not hit Put it on. Three months after sealing in a glass bottle, two of each of the two types of injection-bonded articles were taken out and dried under normal temperature blowing, and then subjected to a tensile tester to measure the bonding force. Similarly, after sealing in a glass bottle, two types each of two types of injection-bonded products were taken out and dried under normal temperature blowing, and then subjected to a tensile tester to measure the bonding force. All showed a breaking force exceeding 30 MPa, and the bonding strength did not decrease in any of the injection-joined product with no flaw and the injection-joined product with a flaw by the water resistance test. From this result, it can be considered that the injection-bonded product without scratches may have water resistance even when the bonding force is reduced in a high-temperature and high-humidity environment, and there is often no problem in practical use. For example, when the injection bonded product is placed in a high humidity environment for a long time, but the temperature is close to room temperature, there is no practical problem.

[Experiment 12] Surface treatment of A5052 piece (NMT)
The same A5052 aluminum alloy sheet material having a thickness of 1.6 mm as in Experimental Example 1 was cut into 45 mm × 18 mm to produce a large number of A5052 pieces. A hole was made in the end of each A5052 piece, and a PVC-coated copper wire was passed through the hole, so that a large number of A5052 pieces were suspended from the copper wire so that a dipping process could be performed simultaneously. NMT surface treatment was performed on these A5052 pieces. First, an aqueous solution (liquid temperature 60 ° C.) containing 7.5% of the aluminum degreasing agent “NE-6” was prepared in a tank, and this tank was used as a degreasing tank. A5052 piece was immersed in this degreasing tank for 5 minutes and washed with tap water (Ota City, Gunma Prefecture). Next, an aqueous solution containing 1% hydrochloric acid (liquid temperature 40 ° C.) was prepared in another tank, and this was used as a preliminary pickling tank. The A5052 piece was immersed in this preliminary pickling tank for 1 minute and washed with ion-exchanged water. Next, an aqueous solution (liquid temperature 40 ° C.) containing 1.5% of caustic soda was prepared in another tank, and this was used as an etching tank. The A5052 piece was immersed in this etching tank for 1 minute and washed with ion-exchanged water. Next, a 3% nitric acid aqueous solution (liquid temperature 40 ° C.) was prepared in another tank, and this was used as a neutralization tank. The A5052 piece was immersed in this neutralization tank for 1 minute and washed with ion-exchanged water. Next, an aqueous solution (liquid temperature 60 ° C.) containing 3.5% hydrated hydrazine was prepared, and this was used as an NMT treatment tank. And the said A5052 piece was immersed for 1 minute in the NMT processing tank, and it washed with ion-exchange water. Thereafter, the A5052 pieces were placed in a warm air dryer at 67 ° C. for 15 minutes and dried. The obtained A5052 pieces were overlapped and wrapped with aluminum foil, and further sealed in a plastic bag for storage.

[Experimental example 13] Injection joining (A5052 / SGX120)
(Injection joining)
In the same manner as in Experimental Example 3, an injection bonded product of A5052 pieces subjected to NMT surface treatment in Experimental Example 12 and “SGX120” in Experimental Example 2 was obtained. The injection-bonded product was annealed for 1 hour in a hot air dryer set at 170 ° C. and allowed to cool. As a result of measuring the joining force of the three injection joints obtained in this way by applying a tensile tester, the breaking force was an average of 25.5 MPa, and all were resin fractures. The resin remaining at the location that was in the joining range was peeled off with a nipper and observed. There was little resin remaining in the bonding range, and it adhered to the entire bonding range, and the bonding state was “good”. This result is equivalent to Experimental Example 4 (injection bonded product by NMT2).

(Pot wet heat test)
Next, 900 g of ion-exchanged water in which 0.7% of hydrated nickel acetate was dissolved was placed in a 1 L beaker, covered with aluminum foil, and placed in an electric hot water pot. Inject water between the outer surface of the beaker and the inner surface of the pot to make the water level so that the beaker floats, set the pot at 98 ° C and leave it for about 1 hour, then peel off the aluminum foil from the beaker and perform ion exchange. As a result of measuring the temperature of the water, it was around 95 ° C. Twenty injection joints were put into this ion-exchanged water, left for 20 minutes, removed from the pot (hydroxylation treatment), washed with water, dried at 70 ° C. for 30 minutes with a hot air dryer, and then at 170 ° C. for 1 hour. Was forcibly dried (annealing treatment). Of the injection-bonded articles after being allowed to cool, three were subjected to a tensile tester and the bonding force was measured. As a result, the breaking force was an average of 25.5 MPa. All were resin fractures, and the joining state was all “good”. That is, the bonding force is not substantially changed by performing the hydroxylation treatment and the annealing treatment.

[Experimental Example 14] High-temperature and high-humidity test Using the injection bonded product subjected to the hydroxylation treatment and annealing treatment of Experimental Example 13, a high-temperature and high-humidity test was conducted. Ten injection joints were put into a high-temperature and high-humidity tester with a temperature of 85 ° C. and a humidity of 85%, and two pieces were taken out after 200 hours, 400 hours, 600 hours, 800 hours and 1000 hours, respectively. The injection-bonded product was dried at 70 ° C. for 10 hours and then cooled at room temperature for 10 hours. Table 3 shows the results of measuring the joining force by applying the injection-joined product after cooling to a tensile tester. All were resin fractures, and the joining state was all “good”. The bonding strength was not substantially changed by performing the high temperature and high humidity test. From this result, it was confirmed that not only NMT2 but also the injection-joined product subjected to the surface treatment for NMT has moisture and heat resistance. However, regarding this result, it is considered that the addition of a high concentration catalyst in the hydroxylation treatment contributed.

[Experimental Example 15] Surface treatment of A6061 piece (NMT2)
An A6061 aluminum alloy sheet having a thickness of 2 mm was obtained and cut into 30 mm × 30 mm to prepare 60 A6061 pieces. Of these, 30 A6061 pieces were processed with an NC milling machine in a range (10 mm × 5 mm) to be bonded to the PPS resin. As shown in FIG. 8, groove processing for forming three grooves 56 having a width of 0.2 mm and a depth of 0.15 mm was performed by a PC milling machine in a range where the aluminum alloy piece 51 was bonded to the PPS resin. The surface treatment for NMT2 was performed on these 30 A6061 pieces and 30 A6061 pieces that were not grooved.

  An aqueous solution (liquid temperature 60 ° C.) containing 7.5% of an aluminum degreasing agent “NE-6” was prepared in a degreasing tank, and this was used as a degreasing tank. The A6061 piece was immersed in this degreasing tank for 5 minutes and washed with tap water (Ota City, Gunma Prefecture). Next, an aqueous solution containing 1% hydrochloric acid (liquid temperature 40 ° C.) was prepared in another tank, and this was used as a preliminary pickling tank. The A6061 piece was immersed in this preliminary pickling tank for 1 minute and washed with ion-exchanged water. Next, an aqueous solution (liquid temperature 40 ° C.) containing 1.5% of caustic soda was prepared in another tank, and this was used as an etching tank. The A6061 piece was immersed in this etching tank for 4 minutes and washed with ion-exchanged water. Next, a 3% nitric acid aqueous solution (liquid temperature 40 ° C.) was prepared in another tank, and this was used as a neutralization tank. The A6061 piece was immersed in this neutralization tank for 3 minutes and washed with ion-exchanged water. Next, an aqueous solution (liquid temperature 60 ° C.) containing 3.5% of hydrated hydrazine was prepared and used as the NMT first treatment tank. And the said A6061 piece was immersed for 1 minute in the NMT 1st processing tank, and it washed with ion-exchange water. Next, an aqueous solution (liquid temperature 25 ° C.) containing 0.5% of hydrated hydrazine was prepared, and this was used as the NMT second treatment tank. And the said A6061 piece was immersed in the NMT 2nd processing tank for 10 minutes, and it washed with ion-exchange water. Thereafter, the A6061 piece was placed in a hot air dryer at 67 ° C. for 15 minutes and dried. The A6061 pieces obtained in this way were stacked and wrapped in aluminum foil, and further sealed in a plastic bag for storage.

[Experiment 16] Injection joining, hydroxylation, and annealing (injection joining)
PPS resin was injection-bonded to 60 pieces of A6061 obtained in Experimental Example 15. Insert the A6061 piece obtained in Experimental Example 15 into the injection mold set at a mold temperature of 140 ° C., and inject “SGX120” in Experimental Example 2, to give two types of injection joints (with and without grooves). 30 pieces of each were obtained. The conditions for injection joining are the same as in Experimental Example 2. All of the obtained injection-joined articles were annealed by placing them in a hot air drier at 170 ° C. for 1 hour and allowed to cool. As a result of measuring the joining force by applying three injection joints without grooves to a tensile tester, the breaking force was an average of 32.1 MPa, and all were shear fractures. In addition, as a result of measuring the joining force by applying three injection joints with grooves to a tensile tester, the breaking force was an average of 31.8 MPa, and all were shear fractures.

(Hydroxylation treatment and annealing treatment)
The remaining injection-bonded materials (2 types, 54 in total) were subjected to hydroxylation treatment and annealing treatment in the same manner as in Experimental Example 13. However, a hydrated nickel acetate aqueous solution (liquid temperature 98 ° C.) having a concentration of 600 PPM was used for the hydroxylation treatment, and the immersion time was 20 hours. As a result of measuring the joining force of the injection-bonded product (3 without grooves and 3 with grooves) after the annealing treatment and measuring the joining force, the breaking force is in the range of 31.2 to 33.5 MPa, all shear breaking Met. There was no difference in the breaking force between the injection joint without groove and the injection joint with groove. From this result, it was confirmed that the hydroxylation treatment and the annealing treatment did not affect the bonding force.

[Experimental Example 17] Pot Wet Heat Test Three each of the two types of injection joints obtained in Experiment Example 16 (without grooves and with grooves) were subjected to a pot wet heat test. Ion exchange water was put in a commercially available electric pot until the 6th minute and set to 98 ° C., and 3 kinds of each of the two injection joints were put into the ion exchange water at 98 ° C., and all were taken out after 20 hours. The taken-out injection bonded product was put into a hot air dryer, dried at 70 ° C. for 10 hours, and further placed at room temperature for 10 hours, and then subjected to a tensile fracture test to measure the bonding force. The breaking force was an average of 18.9 MPa for the injection-joined product without a groove and an average of 30.9 MPa for the injection-joined product with a groove. The joining force was maintained in the grooved injection-joined product, but the joining force was reduced in the injection-joined product without grooving.

[Experimental Example 18] High-temperature and high-humidity test Using the injection bonded product subjected to the hydroxylation treatment and annealing treatment of Experimental Example 16, a high-temperature and high-humidity test was conducted. Two types (grooved and non-grooved) of 10 injection joints were put into a high-temperature and high-humidity tester with a temperature of 85 ° C. and a humidity of 85%, after 200 hours, 400 hours, 600 hours, 800 hours, Two thousand pieces were taken out after 1000 hours, and the taken out injection-joined pieces were dried at 70 ° C. for 10 hours and then cooled at room temperature for 10 hours. Table 4 shows the results of measuring the joining force by applying the injection-joined product after cooling to a tensile tester. It can be confirmed that the bonding strength with a groove is maintained high even in a high temperature and high humidity environment for a long time. That is, for the injection bonded product (with grooves) that showed good results in the pot moist heat test of Experimental Example 17, a high bonding force was maintained even in the test using the high temperature and high humidity tester. On the other hand, as for the injection-bonded product (without grooves) whose bonding strength decreased in the pot moist heat test of Experimental Example 17, the bonding strength decreased with time even in the high-temperature and high-humidity tester.

[Experimental Example 19] Chemical Conversion Treatment Chromate-type chemical conversion treatment was performed on eight injection joints with grooves subjected to the hydroxylation treatment and annealing treatment of Experimental Example 16. Chromate treatment solution “Alchrome 713” (manufactured by Nihon Parkerizing Co., Ltd.) containing chromium trioxide and hydrogen fluoride is diluted with ion-exchanged water to a concentration indicated by the manufacturer (approximately 7%). ° C). The injection-bonded product was immersed in this chemical conversion solution for 2 minutes, washed with water, and placed in a hot air dryer set at 80 ° C. and dried for 30 minutes. In addition, when an aluminum alloy is directly immersed in this chemical conversion treatment liquid, it usually browns, but this time, the color tone did not change by this chemical conversion treatment. As a result of measuring the bonding force by applying three of the chemical injection-treated injection bonded articles to a tensile tester, the breaking force was an average of 30.7 MPa, and it was confirmed that the bonding force was not substantially changed by this chemical conversion treatment. As a result of XPS analysis of the surface of the A6061 piece used in the tensile test (not the bonding range, but also the chuck portion gripped by the tensile tester), it is clear that chromium peaks are observed and chromium ions are deposited. was.

[Experimental Example 20] Coating Treatment Five injection joints with grooves subjected to the hydroxylation treatment and annealing treatment of Experimental Example 16 and five injection-jointed injection-formed articles obtained in Experimental Example 19 (with grooves) The coating process was performed on. These injection-bonded articles were undercoated using “SP10-13631” (manufactured by Musashi Paint Co., Ltd.), an epoxy-modified resin paint. The undercoating was performed by spray coating, and the entire surface was coated (leaving a portion to be gripped with a jig) leaving about 5 mm of the end portion of the resin portion, and then semi-dried by drying at 80 ° C. for 15 minutes. Next, a top coat was applied using “New Garmet # 3000 Black” (manufactured by Tope Co., Ltd.), a fluorine resin paint. The same part as the part where the undercoat was applied was overcoated by spray coating, dried at 80 ° C. for 15 minutes, then heated, and baked at 170 ° C. for 20 minutes.

[Experiment 21] High temperature and high humidity test and salt spray test (High temperature and high humidity test)
A high-temperature and high-humidity test was conducted using two types of painted injection-bonded articles obtained in Experimental Example 20 (without chemical conversion treatment and with chemical conversion treatment). Three types of each of the two types of injection joints were put into a high-temperature and high-humidity tester with a temperature of 85 ° C. and a humidity of 85%, taken out after 1000 hours, and the taken out injection joints were placed under 70 ° C. for 10 hours and dried. Thereafter, it was cooled at room temperature for 10 hours. As a result of measuring the joining force of the injection-joined product after cooling using a tensile tester, the breaking force of the injection-joined product without chemical conversion treatment was 30.2 to 31 MPa, and the breaking strength of the injection-joined product with chemical conversion treatment was 30. The range was 5 to 31.5 MPa. That is, the bonding force did not change depending on the presence or absence of chemical conversion treatment.

(Salt spray test)
In addition, a salt spray test was performed using two types of painted injection-bonded articles obtained in Experimental Example 20 (without chemical conversion treatment and with chemical conversion treatment). A cross cut was made with a cutter knife in the center of each injection-bonded A6061 piece coated with two layers. The cut was deepened to reach the aluminum alloy phase. These injection joints were placed in a salt spray tester (set temperature 35 ° C.) using neutral salt water containing 5% salt. After two cycles of salt water spraying with a spraying time of 8 hours and a break time of 16 hours as one cycle, the injection joint is taken out from the testing machine, washed thoroughly with ion-exchanged water, and then air-dried at room temperature for 1 hour. did. Although the cut mark of the cutter knife was observed, no rust was generated. Subsequently, these injection-bonded articles were subjected to a tensile tester to measure the bonding force, but all of the injection-bonded articles without chemical conversion treatment and the injection-bonded articles with chemical conversion treatment showed a breaking force within a range of 30.2 to 31.5 MPa. . All were shear fractures. There was no difference in bonding strength with or without chemical conversion treatment.

DESCRIPTION OF SYMBOLS 10 ... Aluminum alloy phase 20 ... Fat composition phase 30 ... Aluminum oxide thin layer 51 ... Aluminum alloy piece 52 ... Joining range 53 ... PPS resin composition 54 ... Aluminum hydroxide layer 55 ... Line wound 56 ... Groove

Claims (8)

A composite in which an aluminum alloy and a resin composition containing polyphenylene sulfide are joined,
On the surface of the aluminum alloy, ultrafine irregularities having a period of 20 to 80 nm, or ultrafine recesses or ultrafine protrusions having a diameter of 20 to 80 nm are formed, and the surface layer is a thin layer of aluminum oxide having a thickness of 3 nm or more. And
An aluminum hydroxide layer is formed around the joining range of the aluminum alloy surface and the resin composition. A composite in which an aluminum alloy and a resin composition containing polyphenylene sulfide are joined,
On the surface of the aluminum alloy, ultrafine irregularities having a period of 20 to 80 nm, or ultrafine recesses or ultrafine protrusions having a diameter of 20 to 80 nm are formed, and the surface layer is a thin layer of aluminum oxide having a thickness of 3 nm or more. And
A composite boundary characterized in that a joining boundary line between the aluminum alloy surface and the resin composition is covered with an aluminum hydroxide layer. The composite according to claim 1 or 2, wherein
The composite according to claim 1, wherein unevenness having a period of several μm to several mm is further formed on the surface of the aluminum alloy. A composite according to claim 3, wherein
The complex is a composite having a width of 0.05 to 0.5 mm and a depth of 0.02 to 0.5 mm. A composite according to claim 3, wherein
The complex is a composite having a width of 0.5 to 2.0 mm and a depth of 0.2 to 1.0 mm. The composite according to claim 1 or 2, wherein
One or more element signals selected from chromium, zirconium, manganese, and silicon are detected when the aluminum alloy surface is subjected to elemental analysis by XPS. An aluminum alloy is immersed in an aqueous solution of a water-soluble amine compound, and the surface of the aluminum alloy is covered with ultrafine irregularities with a period of 20 to 80 nm, or ultrafine recesses or ultrafine protrusions with a diameter of 20 to 80 nm, and the surface is covered with the above-mentioned An etching process for adsorbing an amine compound;
The aluminum alloy that has undergone the etching process is inserted into a mold for injection molding, a resin composition containing polyphenylene sulfide is injected onto the surface of the aluminum alloy, injection molding is performed, and a molded product of the resin composition and the An injection joining process for joining aluminum alloys;
A hydroxylation treatment step of immersing the injection-joined product that has undergone the injection joining step in water at 80 ° C. or higher to form an aluminum hydroxide layer on the aluminum alloy surface;
An annealing treatment step of heating the injection bonded product that has undergone the hydroxylation treatment step at a temperature of 150 to 200 ° C. for 20 minutes or more;
The manufacturing method of the composite_body | complex characterized by including. An aluminum alloy is immersed in the first water-soluble amine compound aqueous solution, and the surface of the aluminum alloy is covered with ultrafine irregularities having a period of 20 to 80 nm, or ultrafine concave portions or ultrafine convex portions having a diameter of 20 to 80 nm, and An etching step for adsorbing the amine compound on the surface;
The aluminum alloy that has undergone the etching step is immersed in a second water-soluble amine compound aqueous solution having a concentration of 0.05 to 1% at 15 to 55 ° C. for 1 to 10 minutes to increase the adsorption amount of the amine compound. An adsorption process;
A drying step of drying the aluminum alloy that has undergone the adsorption step at 50 to 70 ° C .;
The aluminum alloy that has undergone the drying step is inserted into a mold for injection molding, a resin composition containing polyphenylene sulfide is injected onto the surface of the aluminum alloy, injection molding is performed, and a molded product of the resin composition and the An injection joining process for joining aluminum alloys;
A hydroxylation treatment step of immersing the injection-joined product that has undergone the injection joining step in water at 80 ° C. or higher to form an aluminum hydroxide layer on the aluminum alloy surface;
An annealing treatment step of heating the injection bonded product that has undergone the hydroxylation treatment step at a temperature of 150 to 200 ° C. for 20 minutes or more;
The manufacturing method of the composite_body | complex characterized by including.

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