JP2007144795A - Method for producing composite of aluminum alloy and resin - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To efficiently produce a composite of an aluminum alloy and a resin which is decorated, excellent in weatherability, and good in productivity in electronic instrument etc. <P>SOLUTION: A shaped aluminum alloy article is subjected to special surface treatment, dried, and inserted into an injection molding mold. By injection-molding PBT, PPS, or a polyamide resin as a resin into the mold, the composite in which the shaped aluminum alloy article and the molded resin are firmly and stably joined to each other can be formed. It was a simple, interesting method in which the most important life of a hydrazine aqueous solution in the special surface treatment, namely the usable treatment area of the solution, is extended to the maximum, and the whole quantity of the solution is not replaced in order to improve the efficiency of mass production in the surface treatment. <P>COPYRIGHT: (C)2007,JPO&INPIT

Description

  The present invention relates to a method for producing a composite of an aluminum alloy and a high-strength resin used for a housing or the like of an electronic device. More specifically, the present invention relates to a method for producing a composite in which an aluminum alloy shaped article and a thermoplastic resin are integrated, and in particular, various electronic devices for mobile devices, home appliances, medical devices, structural parts for vehicles, on-vehicle supplies, and parts for building materials. The present invention also relates to a method for producing a weather-resistant aluminum alloy and resin used for other structural parts and exterior parts.

  Technology for integrating metal and synthetic resin is required from a wide range of industrial fields such as automobiles, home appliances, and parts manufacturing for industrial equipment, and many adhesives have been developed for this purpose. Among these, very good adhesives have been proposed and used. Adhesives that exhibit their functions at room temperature or by heating are used for joining metal and metal, or metal and synthetic resin, and are now a common technique.

  However, various methods have been studied for bonding without using an adhesive. For magnesium, aluminum and its light metals or iron alloys such as stainless steel, a method of integrating a high-strength engineering resin without the use of an adhesive, such as injecting a resin component on the metal side Various methods for bonding at the same time as molding have been disclosed, but they are not yet in full use.

  In this connection, the present inventors have intensively researched and developed for practical use. As a result, polybutylene terephthalate resin (hereinafter referred to as “PBT”), polyphenylene sulfide resin (hereinafter referred to as “PBT”), after surface treatment of immersing the aluminum alloy shaped article in an aqueous solution of a water-soluble amine compound such as ammonia, hydrazine, or a water-soluble amine. (Hereinafter referred to as “PPS”) or a thermoplastic resin composition mainly composed of polyamide resin, when brought into contact under high temperature and high pressure, the resin molded product by injection molding and the aluminum alloy shaped product have a particularly strong bonding strength. Found this technology to be found. Regarding the technology related to this, the present applicant has disclosed a structure for integrating an aluminum alloy and a resin by injection and the technology (see Patent Documents 1, 2, and 3).

JP 2003-170531 A JP 2003-200453 A JP 2005-144987 A

  The inventors conducted various detailed tests in order to confirm the effect of injection-bonding a synthetic resin such as PBT or PPS to an aluminum alloy using the above-described invention. In addition, in preparation for commercial production of mobile electronic device cases and the like, the types of chemicals to be used for the surface treatment described above, appropriate disposal of chemicals, and the frequency of building fluids have been studied.

  As a result, it was hydrazine that was judged to be the most suitable for commercial production among water-soluble amine compounds that are chemicals for surface treatment. The surface treatment is effective at a concentration of several percent, and this is because an aqueous solution of this concentration has a low odor and can be completely decomposed into sodium chloride by addition of sodium hypochlorite at the time of disposal. Ammonia is effective at high concentrations, but high-concentration aqueous solutions have a bad odor. The use of water-soluble amines with a relatively low odor was also considered. However, it is assumed that the amine salt is neutralized with sulfuric acid and discarded as amine sulfate. did not understand. Including these, it was considered preferable to use hydrazine, specifically monohydric hydrazine supplied industrially at low cost.

Actually, a large amount of aluminum alloy was dipped using an aqueous solution of hydrazine having a concentration of several percent. In a normal plating mass production line, the daily processing amount is said to be 1 to 20,000 dm ² , so that this was compared with the usable liquid capacity. Depending on the amount of liquid hydrazine aquarium, a 600 mm × 600 mm × 1100 mm height of the tank Put the solution to about 800mm and the liquid weight of 300 liters injection joining strength of 20,000 dm ² processing liquid processing products from the middle has been the goal of Suddenly declined and could not be handled. If the amount of treatment is small, not only will the amount of chemicals used increase, but the time required to make a new hydrazine solution by making new adjustments will also occupy a significant portion of the working time. For this reason, the present inventors conducted extensive research and development.

The present invention takes the following means to achieve the above object.
The method for producing a composite of an aluminum alloy and a resin according to the present invention 1,
A step of forming an aluminum alloy shape from an aluminum alloy, a step of immersing the aluminum alloy shape in a hydrazine aqueous solution, a step of inserting the aluminum alloy shape processed in the dipping step into an injection mold, The aluminum alloy and the resin are integrated with at least a step of injecting a thermoplastic resin composition mainly composed of one or more selected from polybutylene terephthalate resin, polyphenylene sulfide resin, and polyamide resin into the injection mold. In the production of the composite, when the performance of the aqueous hydrazine solution is reduced, the mass production capacity of the aqueous hydrazine solution is increased by adjusting a new aqueous hydrazine solution using a part of the used aqueous hydrazine solution. Of aluminum alloy and resin composites It is the law.

The method for producing a composite of an aluminum alloy and a resin according to the present invention 2,
A step of forming an aluminum alloy shape from an aluminum alloy, a step of immersing the aluminum alloy shape in a hydrazine aqueous solution, a step of inserting the aluminum alloy shape processed in the dipping step into an injection mold, The aluminum alloy and the resin are integrated with at least a step of injecting a thermoplastic resin composition mainly composed of one or more selected from polybutylene terephthalate resin, polyphenylene sulfide resin, and polyamide resin into the injection mold. In the production of the composite, a method for producing a composite of an aluminum alloy and a resin, wherein the mass production capacity of the hydrazine aqueous solution is increased by adding aluminum hydroxide to the hydrazine aqueous solution.

[Description of each of the above configurations of the present invention]
Hereinafter, the means will be described in detail with respect to the method for producing a composite of a weather-resistant aluminum alloy and resin according to the present invention described above. Since the technology for injection molding a thermoplastic resin composition mainly composed of polybutylene terephthalate (PBT), polyferene sulfide (PPS), or polyamide resin in an aluminum alloy is described in the above-mentioned patent documents and the like, A detailed description of the technology related to this will be omitted. Although the present invention formally includes the features described above, it is essentially the same. In order to explain these, a standard treatment method and a manufacturing method will be described first for all steps including steps other than surface treatment. Next, a method for improving the liquid performance of the main treatment step in the surface treatment will be described.

[Creation of aluminum alloy shape]
An aluminum alloy shaped article is a part made of an aluminum alloy and constituting a part of a composite. Aluminum alloys are roughly classified into wrought alloys and foundry alloys. On the other hand, it can be broadly classified into a non-heat treatment type alloy that increases hardness and tensile strength only by work hardening and a heat treatment alloy that improves mechanical properties by heat treatment. Examples of the aluminum alloy belonging to the non-heat treatment type alloy include an Al—Mg alloy, an Al—Mn alloy, and an Al—Mg—Mn alloy. Examples of the aluminum alloy belonging to the heat treatment type alloy include an Al—Cu—Mg alloy, an Al—Zn—Mg alloy, an Al—Mg—Si alloy, and a heat-resistant aluminum alloy. Casting alloys are further divided into molds, sand molds, shell castings, die castings, and the like.

  Thus, various types of aluminum alloys used in the present invention are known, and are A1000 to A7000 series standardized by JIS (Japanese Industrial Standard), ADC1 to 12 of aluminum alloys for die casting, and the like. In principle, these known aluminum alloys are used for the aluminum alloy parts used in the present invention. Aluminum alloy is an aluminum alloy with a desired shape by cutting, pressing, milling, turning, electrical discharge machining, drilling, forging, pressing, grinding, polishing, etc. Processed into a shape. The aluminum alloy shaped article becomes a part for insertion into an injection mold.

  Many of the finished products are usually covered with machining oil. In such a case, before sending it to the degreasing step of the next step, which will be described later, use a solvent degreasing device that uses a solvent such as trichlene, methylene chloride, or isoparaffinic hydrocarbon oil to remove the processing oil adhering to the surface. It is preferable to keep it.

[Surface treatment / degreasing process]
When a surface treatment is performed on an aluminum alloy shaped article and a treatment suitable for injection bonding is performed, this is divided into three stages and referred to as a degreasing step, a pretreatment, and a main treatment. The degreasing step is intended to remove processing oil, finger oil, and the like, but when the processing oil is firmly attached as described above, the degreasing step often cannot be completely removed. For this reason, as described above, it is preferable that the solvent is once passed through a solvent degreasing apparatus and then introduced into the degreasing step. This process is started when the aluminum alloy has a low degree of adhesion of processing oil or the like and the degree of contamination is such that oil or fat adheres.
A commercially available degreasing agent for aluminum alloys can be used as the degreasing material. It is preferable to put a commercially available degreasing agent for aluminum alloy into hot water and dissolve it, and immerse the aluminum alloy shaped article in the degreasing agent aqueous solution at a temperature and time specified by the manufacturer, that is, most at 50 to 70 ° C. for 5 to 10 minutes. After lifting from the degreasing tank, wash with water.

[Surface treatment / Pretreatment]
There are two types of pretreatment that the present inventors consider preferable, pretreatment I and pretreatment II, and the immersion liquid used in pretreatment I is an acidic or basic aqueous solution. As a basic solution, a 0.5 to 3.0% concentration aqueous solution of sodium hydroxide is used at 35 to 40 ° C, and as an acidic solution, a 0.5 to 5.0% concentration hydrochloric acid or nitric acid solution is used at 35 to 40 ° C. Use with temperature control. Pretreatment I is used for A1000 series and A5000 series alloys with less copper and silicon. On the other hand, in the pretreatment II, an acidic aqueous solution is mainly used, and an aqueous solution containing nitric acid and hydrofluoric acid or a hydrofluoric acid derivative is used as the acidic liquid.

  The pretreatment II is used for aluminum alloys containing copper and silicon, that is, casting alloys such as A2000 series, A6000 series, A7000 series, ADC10, ADC12, etc. defined by JIS. In any case, the purpose of the pretreatment is to immerse in an acid-base solution for several minutes and roughly etch to chemically remove the surface layer film so that it is suitable for the subsequent main treatment. Wash with water and send the shaped aluminum alloy to the next process.

[Surface treatment / Main treatment]
The pre-treated aluminum alloy shaped article is immersed in a hydrazine aqueous solution. This is the main processing referred to in the present invention. The purpose of this step is to finely etch the surface of the aluminum alloy shaped article obtained in the previous step and to adsorb hydrazine. The standard liquid treatment method is a 2-10% concentration of hydrazine monohydrate, preferably 3-5% aqueous solution at 50-70 ° C., immersed for 45-90 seconds, washed with water and dried with hot air at 60-80 ° C. It is a method to do.

[Thermoplastic resin composition]
Next, the thermoplastic resin composition used in the present invention and injection bonding will be described. The thermoplastic resin composition containing PBT, PPS, or polyamide resin as a main component is used in the present invention. In order to maintain the bonding strength with the metal for a long period of time, these resin compositions must contain 20 to 50% of fiber components and inorganic powder components, so-called fillers. By including the filler, the linear expansion coefficient of the resin composition is set to 2-3 × 10 ⁻⁵ ° C. ⁻¹ as much as possible as that of the aluminum alloy. The resin component other than the filler is not PBT, PPS, or polyamide resin alone, but a compound of PBT and polyethylene terephthalate resin (hereinafter referred to as PET), a compound of PPS and polyolefin polymer, nylon 6 and aromatic nylon. A compound or the like is also preferable.

[Injection molding, injection joining]
In the present invention, “injection joining” means that after an aluminum alloy shaped article is inserted into an injection mold, a thermoplastic resin composition is injected into the injection mold, and the thermoplastic resin composition and the aluminum alloy shape are injected. It means to fix (adhere) an object. A specific injection joining procedure is as follows. First, the thermoplastic resin composition described above is first put into a dryer and dried to prepare for injection molding. An injection mold is prepared, the movable mold is opened, and the aluminum alloy shaped article (part) subjected to the above treatment is inserted into one of the fixed molds. After inserting the aluminum alloy shape, the movable mold is closed and the thermoplastic resin composition is injected.

  After the injection molding, when the movable mold is opened, an integrated product which is a composite in which the resin composition and the aluminum alloy are joined is obtained. The composite is taken out from the injection mold and the fixing (adhesion) is completed. The injection temperature is preferably the same or slightly higher than when the resin composition to be used is usually injection-molded. Other molding conditions do not need to be greatly changed as compared with normal injection molding, but high-speed and high-pressure injection conditions are preferable in order to increase the bonding force (fixing force). On the other hand, the mold temperature is preferably 120 ° C or higher for any resin type, and in terms of design, the structure allows the gas to sufficiently escape from the mold, and the flow path to the cavity is shortened. It is preferable that the runner and gate structure have a sufficiently high temperature of the resin in contact with the aluminum alloy.

[Evaluation of injection joining force]
Both the aluminum alloy and synthetic resin integrated product obtained in the present invention are very strongly bonded. The simplest evaluation method is to obtain an integrated product of an aluminum alloy having a shape shown in FIG. 1 and a PPS resin, and to pull both ends with a tensile tester and measure the breaking force. In many cases, the present inventors use PPS resins described in Examples below, which include about 20% glass fiber and a polyolefin resin and a compatibilizer, as a PPS resin for measuring the injection bonding force. The injection joining using this resin was very strong and stable, so it was suitable for evaluating the liquid-treated aluminum alloy side.

In addition, in order to sequentially surface-treat a large number of aluminum alloy shapes having various shapes, several small aluminum pieces having a thickness of 1.6 mm and 18 mm × 45 mm are simultaneously surface-treated, and the PPS of the small aluminum pieces after the surface treatment is obtained. Resin injection bonding and its bonding strength were evaluated. This evaluation judged that the surface treatment was good when the joining force had a shear breaking strength of 24.5 Mpa (250 Kgf / cm ² ) or more. For example, a hydrazine aqueous solution tank is built and the surface treatment proceeds one after another, and three small aluminum alloy pieces are simultaneously processed every 250 dm ² .
All these small aluminum pieces are injection-bonded and an experiment of tensile shear fracture is performed. Here, if even one of the three integrated pieces of small aluminum alloy pieces corresponding to a treatment area of 7250 dm ² has reduced the shear breaking strength, it is determined that the mass production capacity of the aqueous hydrazine solution is 7000 dm ² .

[This treatment method that takes mass production capacity into consideration]
As an example of this treatment liquid, an aqueous solution of 3.5% concentration of hydrazine monohydrate (an aqueous solution of 2.24% concentration as hydrazine) was 300 liters, and this was used as a hydrazine aqueous solution tank. When the deterioration degree of this hydrazine aqueous solution was evaluated by the method described above, the following results were obtained. Until the A5052 aluminum alloy 8500 dm ² subjected to the degreasing process and the pretreatment process was processed with respect to this liquid, the injection bonding force was not inferior, but the injection bonding force was lowered in the aluminum alloy processed after this. Since seen as difficult to be devised such as extending the immersion time indicating the original intense injection joining strength, mass production capability of hydrazine aqueous solution was determined to 8500dm 2 / 300l ^(l), this liquid spent Made with hydrazine aqueous solution.

One measure for improving the mass production capacity of the main treatment hydrazine aqueous solution is to discard the entire amount of the used hydrazine aqueous solution, scraping and discarding the supernatant in a plastic bucket, leaving 1/2 to 1/3 amount. An amount of new hydrazine aqueous solution corresponding to the amount is added to make a new solution. With the new hydrazine aqueous solution thus prepared, its mass productivity is much higher than 8500 dm ² . This aqueous solution is also treated for about 8500 dm ² and then subjected to the same disposal and new adjustment. Even mass production ability of aqueous hydrazine solution by repeating several times reaches 15000~20000dm ² / 300l. The peculiar point of this method is that the white adhering crystals and white precipitates that appear to be aluminum hydroxide adhering to the inside of the hydrazine aqueous solution tank are left and stored in the tank.

  Another method is to add some amount of commercially available high purity aluminum hydroxide powder. In the first treatment after installing the surface treatment plant, the inside of the hydrazine aqueous solution tank is naturally clean and nothing is attached. Therefore, since the mass production capacity in this tank is low as described above, it is possible to add about 10 g / 300 l of aluminum hydroxide powder and stir well to improve the early processing capacity. Even in this case, it is preferable to repeat the method of leaving the ½ to 残 す amount as described above without discarding the entire amount of the used hydrazine aqueous solution for early mass productivity improvement.

The present inventors assumed the following as reasons for improving mass productivity. That is, the hydrazine _(N 2 _{H 4)} Water hydrazonium ions _{(N 2 H} ^{5 +)} and hydroxyl ions in aqueous solution ^- which occur in equilibrium reactions, the OH (OH) ^- and a basic original It has become.
N ₂ H ₄ + H ₂ O⇔ N ₂ H ₅ ⁺ + OH ⁻

However, the basicity is weak, and the pH is about 9.9 to 10.0 in a 3.5% monohydric hydrazine aqueous solution at 60 ° C. Aluminum metal, OH ⁻ and water react to produce aluminate ions (Al (OH) ₄ ⁻ ) and hydrogen gas.
Al + OH ⁻ + 3H ₂ O → Al (OH) ₄ ⁻ + 3 / 2H ₂ ↑

By this reaction, the aluminum alloy is finely etched, while OH ⁻ is consumed. When the immersion of the aluminum alloy is repeated, OH ⁻ decreases and the basicity weakens, but there is an equilibrium reaction, so that the PH does not decrease rapidly. In addition, the resulting aluminate ion (Al (OH) ₄ ⁻ ) is not very stable as a salt because the hydrazonium ion (N ₂ H ₅ ⁺ ) as a counter ion is not strong, and eventually aluminum hydroxide (Al (OH) ) ₃₎ and OH ^- it is expected to be broken down into. I imagined that aluminum hydroxide was involved in this decomposition reaction.
Al (OH) ₄ ⁻ + Al (OH) ₃ → 2Al (OH) ₃ + OH ⁻

When the decomposition reaction proceeds smoothly to aluminate ions is changed to aluminum hydroxide, OH ^- is rapidly further decrease the rate of the PH is lower because the resurrection, i.e. the aqueous solution was considered to last. In actual mass production, it was not possible to confirm a decrease in the injection joining force until PH decreased to about 9.4.

Further, when a large amount of aluminum alloy was processed and the processing was continued to about PH 9.2, the injection joining ability of the aluminum alloy obtained during this period was 9.8 to 24.5 Mpa (100 to 250 Kgf / cm ² ). The injection joining ability started to vary. It was difficult to obtain a high strength injection joining force with an aluminum alloy treated with a liquid having this value lowered to pH 9.2 or lower. When the test aluminum alloy is processed simultaneously in the mass production state and its injection joining ability is measured, and when the shear breaking force is observed to be less than 24.5 Mpa (250 Kgf / cm ² ), the liquid life of the aqueous hydrazine solution is Judge that it came.

  The PH at that time was 9.3 to 9.4. Therefore, the present inventors considered that it is a good measure to delay the decrease in pH by rapidly decomposing aluminate ions and reducing the concentration in the solution. At the same time, if aluminum hydroxide really acts as a catalyst for this decomposition reaction, it is convenient that aluminum hydroxide crystals gradually adhere to the inner wall of the tank as the reaction repeats, so there is no need to scrape off. I thought. In fact, do not discard the entire amount of hydrazine aqueous solution that has reached the end of life, scrape and discard about half of the clean aqueous solution at the top, and make up for it after leaving white deposits and suspension on the side walls and bottom of the tank. I tried a new liquid. It was found that the life of the hydrazine aqueous solution gradually increased and doubled as this method was repeated.

Thus, the aluminum hydroxide adhering to the hydrazine aqueous solution tank is not a dirt but an important substance, and the aluminum hydroxide crystals suspended in the aqueous solution should not be discarded. However, the amount of aluminum metal dissolved in this tank is considered to be about several grams even if aluminum or aluminum alloy of tens of thousands of dm ² is processed, and it takes time to cover the inner wall with white crystals. Therefore, it was considered that the addition of aluminum hydroxide can be expected to have an effect at an early stage, and was confirmed by experiments.

  Means for measuring the exact concentration of various ions in the liquid that change from moment to moment have not been developed except for hydroxide ions, and the reaction mechanism could not be elucidated. It is derived from epidemiological estimates and statistical results of repeated mass production results.

  As described in detail above, the method for producing a composite of an aluminum alloy and a resin according to the present invention is a structure that can be integrated without causing the thermoplastic resin composition and the aluminum alloy shaped article to be easily peeled off. Established manufacturing technology. That is, it is useful for improving the mass productivity of the surface treatment method applied to the aluminum alloy shaped article, although it is a very simple method.

  Various tests were carried out using actual aluminum alloy shapes. Since the effect was confirmed in the Example, Embodiment of this invention is described instead of an Example. However, it goes without saying that the present invention is not limited to the examples.

Hereinafter, an Example is shown and the end of this invention is shown.
[Example 1]
[Example of preparation of PPS resin and resin composition thereof]
A 50 liter autoclave equipped with a stirrer was charged with 6,214 g of Na ₂ S · 2.9H ₂ O and 17,000 g of N-methyl-2-pyrrolidone and gradually heated to 205 ° C. while stirring under a nitrogen stream. 1,355 g of water was distilled off. After cooling this system to 140 ° C., 7,160 g of p-dichlorobenzene and 5,000 g of N-methyl-2-pyrrolidone were added, and the system was sealed under a nitrogen stream. This system was heated to 225 ° C. over 2 hours and polymerized at 225 ° C. for 2 hours, then heated to 250 ° C. over 30 minutes, and further polymerized at 250 ° C. for 3 hours. After completion of the polymerization, the mixture was cooled to room temperature and the polymer was isolated using a centrifuge. The solid was repeatedly washed with warm water and dried at 100 ° C. for a whole day to obtain PPS having a melt viscosity of 280 poise. This PPS was further cured for 3 hours at 250 ° C. in a nitrogen atmosphere. The melt viscosity of the obtained PPS was 400 poise.

  6.5 kg of this PPS and 1.5 kg of ethylene-acrylic acid ester-maleic anhydride terpolymer “Bondyne TX8030 (manufactured by Arkema)”, 0.4 kg of epoxy resin “Epicoat 1004 (manufactured by Japan Epoxy Resin)” Was uniformly mixed with a tumbler in advance. Thereafter, the glass fiber “RES03-TP91 (manufactured by Nippon Sheet Glass Co., Ltd.)” having an average fiber diameter of 9 μm and a fiber length of 3 mm is added from the side feeder with a twin screw extruder “TEM-35B (manufactured by Toshiba Machine Co., Ltd.)”. The PPS composition was melted and kneaded at a cylinder temperature of 300 ° C. while being pelletized while being fed at a weight percent. The obtained PPS composition was dried at 175 ° C. for 5 hours to obtain a PPS composition.

[Preparation of aluminum alloy parts and aluminum alloy pieces]
A 1 mm thick A5052 aluminum alloy plate was cut to a size of 270 mm × 270 mm to produce a large number of plate-like parts having a surface area of 14.6 dm ² . An immersion jig was prepared, and 30 parts were filled per jig and filled with 438 dm ² of aluminum alloy per jig. On the other hand, a 1.6 mm-thick A5052 aluminum alloy plate was cut to produce a large number of 18 mm × 45 mm small aluminum alloy pieces, and 2 mmφ holes were made in each end portion. A PVC cover copper wire was passed through the three holes of the aluminum alloy pieces and the copper wires were bent so that the pieces were not in contact with each other, and then tied to the jig.

In short, an aluminum alloy part 438 dm ² and three small aluminum alloy pieces were attached to the immersion jig and processed at the same time. Ten jigs were prepared to prepare for immersing a large amount of aluminum alloy.

[Surface treatment of aluminum alloy]
A commercially available aluminum degreasing agent “NE-6 (manufactured by Meltex)” was dissolved in hot water at a concentration of 7.5% and immersed in a tank (degreasing tank) at 75 ° C. for 7 minutes, and three consecutive installations were made. Then, it was sequentially immersed in a washing tank and washed with water. Subsequently, it was immersed for 1 minute in a preliminary pickling tank containing a 1% hydrochloric acid aqueous solution at 40 ° C., and then sequentially immersed in a water washing tank that was installed three times in succession and washed with water. Subsequently, it was immersed for 1 minute in an alkaline etching tank containing a 1.5% aqueous solution of caustic soda at 40 ° C., and then sequentially immersed in a water-washing tank that was installed three times for washing. Subsequently, it was immersed for 1 minute in the neutralization tank containing 3% nitric acid aqueous solution which was 40 degreeC, and it was immersed in the water-washing tank currently installed three times, and washed with water. This is the degreasing process and the pretreatment process.

  Subsequently, it was immersed for 1 minute in a hydrazine aqueous solution tank containing 300 liters of a 3.5% strength monohydric hydrazine aqueous solution at 60 ° C., and then sequentially immersed in three consecutively installed water washing tanks for water washing. This is the processing step. The jig was placed in a large hot air dryer and dried with hot air at 40 ° C. for 10 minutes and 67 ° C. for 10 minutes. All aluminum alloy parts were taken out from the jig and discarded, and one small aluminum alloy piece was wrapped and stored in aluminum foil.

In this immersion cycle, new aluminum alloy parts and alloy pieces were successively placed, and the treatment was continued in an 8-minute cycle. In terms of the number of processing jigs, 40 jigs were used. The amount of aluminum alloy processed by 40 jigs is 438 × 40 → 17520 dm ² . The pH of the hydrazine tank was 10.1 immediately after the building liquid, but was 9.4 after 20 jigs and 9.2 after 40 jigs were processed.

[Measurement of injection joining ability of aluminum alloy pieces]
The above PPS composition is used as the thermoplastic resin composition. The aluminum alloy piece was inserted into an injection mold set at 140 ° C., and the resin composition was injected at an injection temperature of 300 ° C. The mold was opened to obtain an integrated product having the shape shown in FIG. Three aluminum alloy pieces obtained for each surface-treated jig were sequentially injected and joined to obtain three resin-metal integrated products.

About 20 minutes after injection joining, both ends of the integrated product were pulled and broken with a tensile tester, and the breaking force was measured. When the rupture force of a small aluminum alloy piece and PPS resin integrated for each jig is obtained, and even when one piece becomes 24.5 Mpa (250 Kgf / cm ² ) or less, the processing up to the previous jig is performed. The product was an OK-treated product. As a result of actual implementation, up to 20 jigs were OK. Therefore, 300 liters of hydrazine water was 438 × 20 → 8760 dm ² .

[Building solution of hydrazine aqueous solution and repeated surface treatment]
Only the hydrazine tank was newly adjusted by the following method on the next day after the surface treatment 40 jig was performed. That is, on the second day, a 3.5% aqueous solution of hydrated hydrazine used on the first day in a cleanly washed plastic bucket was scraped out several times from the top and transferred to a waste tank to make the remaining liquid volume 120 liters. In short, 60% was discarded. Thereafter, 6.3 kg of hydrated hydrazine and ion-exchanged water were added to make a total volume of 300 liters. Since the slightly white crystals adhered to the inner wall of the tank in the previous day's treatment, this is important. All liquid temperatures were controlled, and the treatment was started in the same manner as the previous day. Processing was performed up to 20 jigs. In the same manner as the previous day, an aluminum alloy piece was subjected to an injection joining test, and a tensile test was also performed to confirm that all treatments were OK.

The next day (the third day from the beginning) was constructed in the same manner as the previous day while partially discarding the hydrazine aqueous solution. The pH immediately after the building fluid was 9.8. Surface treatment was performed up to 20 jigs. Similarly, a holiday of 2 days was sandwiched between the 2nd day to the 5th day and the 6th day, and the same thing as the pretreatment day was repeated until the 10th day. As a result, the cumulative processing amount was 40 jigs + 20 jigs × 9 → 220 jigs, which was 96350 dm ² . As a result, a considerable amount of white crystals adhered to the inner wall of the hydrazine water tank.

[Building solution of hydrazine aqueous solution and repeated surface treatment / 2]
In the experiment on the 11th day with a holiday of 2 days after the 10th day, the hydrazine aqueous solution was prepared in the same manner as the 10th day, but the number of surface-treated jigs was 50. A small aluminum alloy piece was also attached to the jig, and the injection joining ability of each jig was inspected. As a result, in the tensile fracture test of the integrated product obtained by injection joining from the aluminum alloy pieces up to 44 jigs, a product of 24.5 Mpa (250 Kgf / cm ² ) or less was not obtained. That is, mass productivity in a 300 liter hydrazine water tank was improved to 438 dm ² × 44 → 19272 dm ² . Further, the PH of the hydrazine tank on this day was 9.9 after the erection liquid meal, and the PH after 44 jigs was 9.4.

[Example 2]
[Surface treatment of aluminum alloy]
In the same manner as in Example 1, aluminum alloy parts and small aluminum alloy pieces were made and filled in a jig. And the following surface treatment line was prepared similarly to Example 1, and the immersion process was performed. That is, the immersion jig was immersed for 7 minutes in a tank (degreasing tank) in which a commercially available aluminum degreasing agent “NE-6 (manufactured by Meltex)” was dissolved in hot water at a concentration of 7.5% to 75 ° C., and then three consecutive times. Then, it was sequentially immersed in a water washing tank installed and washed with water.

  Subsequently, it was immersed for 1 minute in a preliminary pickling tank containing a 1% hydrochloric acid aqueous solution at 40 ° C., and then sequentially immersed in a water-washing tank installed three times for washing with water. Subsequently, it was immersed for 1 minute in an alkaline etching tank containing a 1.5% aqueous solution of caustic soda at 40 ° C., and then sequentially immersed in a water-washing tank that was installed three times for washing. Subsequently, it was immersed for 1 minute in the neutralization tank containing 3% nitric acid aqueous solution which was 40 degreeC, and it was immersed in the water-washing tank currently installed three times, and washed with water.

  Next, 300 liters of a 3.5% strength monohydric hydrazine aqueous solution was added, 20 g of aluminum hydroxide was further added, the temperature was raised to 60 ° C., and then immersed for 1 minute in a hydrazine aqueous solution tank that had been stirred for 5 minutes or more. It was sequentially immersed in a water washing tank that was installed three times and washed with water. The jig was placed in a large hot air dryer and dried with hot air at 40 ° C. for 10 minutes and 67 ° C. for 10 minutes. All aluminum alloy parts were taken out from the jig and discarded, and one small aluminum alloy piece was wrapped and stored in aluminum foil. A new aluminum alloy part and an alloy piece were put on this immersion cycle and sequentially processed in an 8-minute cycle. In terms of the number of processing jigs, 40 jigs were used.

Using the PPS composition tested in Example 1 as a thermoplastic resin composition, the aluminum alloy piece was inserted into an injection mold set at 140 ° C., and the resin composition was injected at an injection temperature of 300 ° C. . The mold was opened to obtain an integrated product. About 20 minutes after injection joining, both ends of the integrated product were pulled and broken by a tensile tester, and the breaking force was measured. When the breaking force for each jig was obtained and even one piece became 24.5 Mpa (250 kgf / cm ² ) or less, the treated product up to the previous jig was regarded as an OK treated product. As a result of actual implementation, it was OK to 29 jigs. Compared with the data on the first day of Example 1, the processing amount of the OK product increased.

FIG. 1 is a shape diagram showing a shape after joining an aluminum alloy shaped product and a thermoplastic resin composition.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Aluminum alloy shape 2 ... Thermoplastic resin composition 3 ... Composite 4 ... Joining surface

Claims (2)

Forming an aluminum alloy shape from an aluminum alloy;
Immersing the aluminum alloy shaped article in a hydrazine aqueous solution;
Inserting the aluminum alloy shaped article treated in the dipping process into an injection mold; and
A step of injecting a thermoplastic resin composition mainly composed of one or more selected from polybutylene terephthalate resin, polyphenylene sulfide resin, and polyamide resin into the injection mold. In the production of the composite
When the performance of the hydrazine aqueous solution deteriorates, a mass production capacity of the hydrazine aqueous solution is increased by adjusting a new hydrazine aqueous solution by using a part of the used hydrazine aqueous solution. Body manufacturing method. Forming an aluminum alloy shape from an aluminum alloy;
Immersing the aluminum alloy shaped article in a hydrazine aqueous solution;
Inserting the aluminum alloy shaped article treated in the dipping process into an injection mold; and
A step of injecting a thermoplastic resin composition mainly composed of one or more selected from polybutylene terephthalate resin, polyphenylene sulfide resin, and polyamide resin into the injection mold. In the production of the composite
A method for producing a composite of an aluminum alloy and a resin, wherein mass production capacity of the hydrazine aqueous solution is increased by adding aluminum hydroxide to the hydrazine aqueous solution.

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