JP4076807B2 - Aluminum alloy-resin composite and its manufacturing method - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a composite of an aluminum alloy and a resin and a method for producing the same. More specifically, regarding a structure in which a thermoplastic resin is integrated with an aluminum alloy shaped product manufactured by various machining methods, a housing for electronic equipment, a housing for household appliances, a structural component for automobiles, The present invention relates to a composite of an aluminum alloy and a resin used for various structural machine parts and a manufacturing method thereof.
[0002]
[Prior art]
A technology for integrating a metal and a resin is required from a wide range of fields such as manufacturing parts for automobiles, home appliances, industrial equipment, and the like, and many adhesives have been developed for this purpose. Among these are very good adhesives. Adhesives that exhibit their functions at room temperature or when heated are used for joining metal and synthetic resin together, and this joining method is now a common technique.
However, it has been studied in the past whether there is a more rational joining method that does not use an adhesive. A method of integrating high-strength engineering resin without the use of adhesives to iron alloys such as magnesium, aluminum and its alloys such as light metals, stainless steel, such as injection molding of resin components on the metal side The method of bonding (fixing) by a method, the “injection bonding method” defined by the inventor for short (however, it does not mean only the molding method by injection molding) has not been put into practical use at present.
[0003]
The inventors proceeded with intensive research and development, and after dipping an aluminum alloy shaped article in an aqueous solution of a water-soluble reducing agent, contact with a thermoplastic resin composition mainly composed of an alkylene terephthalate resin under high temperature and high pressure is specific. It was discovered that the adhesion strength (used in the present invention synonymously with “adhesion strength”) increases. This was proposed as Japanese Patent Application No. 2001-314854.
The present inventors have paid particular attention to aluminum alloys among metal alloys. Aluminum is lightweight and abundant as a resource. With this alloying and surface treatment, in addition to the excellent extensibility, electrical conductivity, and thermal conductivity that are the original physical properties, it is possible to increase the strength, corrosion resistance, free machinability, and extensibility by alloying. This is because it is currently used in a wide range of fields. In particular, if personal information is further developed and mobile electronic devices are used for general purposes in the future, the demand for weight reduction of these devices is expected to increase. In this respect, aluminum alloys are expected to be further utilized.
[0004]
The inventors focused on a thermoplastic resin composition mainly containing an aluminum alloy and polybutylene terephthalate (hereinafter referred to as “PBT”) among the inventions described above by the inventors. The experiment was repeated on the horizontal development of the invention. In the above-described invention, the aluminum alloy was characterized in that it was treated with an aqueous solution of a water-soluble reducing agent, but even if a reducing agent was used, the surface was instantly oxidized by oxygen in the air when taken out from the treated aqueous solution, In terms of the final surface state, it was observed by surface analysis by X-ray electron spectroscopy (XPS) that the surface was not in a zero-valent aluminum metal state.
On the other hand, the hydrazine mainly used in the above-mentioned invention is not particularly dangerous, but it was considered important to confirm effective treatment chemicals that were surface-treated other than this. Taking these into account, we decided to make a hypothesis and conduct a proof experiment of the injection adhesion theory. This is because it was considered useful in developing a reliable injection bonding method.
[0005]
By developing the inventors' invention described above, hydrazine and expensive sodium borohydride (NaBH) _Four ), Aluminum hydride lithium (LiAlH) difficult to handle _Four I tried to develop a method to achieve the same purpose by treating the surface of aluminum alloy without using a reducing agent.
There are many types of aluminum alloys with improved strength and other properties. There is also a need for a pretreatment method in which a resin can be bonded with satisfactory injection adhesive strength to aluminum alloys containing magnesium, silicon, copper, and other metals.
[0006]
[Problems to be solved by the invention]
The present invention has been made based on the technical background as described above, and achieves the following object.
An object of the present invention is to obtain a composite of an aluminum alloy and a resin, and a method for producing the same, by treating the surface of the aluminum alloy so that the thermoplastic resin composition and the aluminum alloy shaped article are not easily peeled off. It is in.
Another object of the present invention is a composite of aluminum alloy and resin, and its manufacture, which can be used to make housings, parts, structures, etc. for various devices that have no problem in shape, structure or mechanical strength. There is to get a way.
Still another object of the present invention is to obtain a composite of aluminum alloy and resin and a method for manufacturing the same, which are useful for reducing the weight of housings, parts, structures, etc. of electronic devices and simplifying the device manufacturing process. is there.
[0007]
[Means for Solving the Problems]
In order to achieve the above object, the present invention employs the following means.
The composite of aluminum alloy and resin of the present invention is
An aluminum alloy shaped article that has undergone a dipping step of dipping in a 50% aqueous solution of 5% hydrated hydrazine for 2 minutes;
On the surface of the aluminum alloy shaped article, polybutylene terephthalate, a copolymer mainly composed of polybutylene terephthalate, and Polybutylene terephthalate One or more selected from thermoplastic resin compositions containing as a component are adhered by injection molding
It is characterized by that.
[0008]
The method for producing a composite of an aluminum alloy and a resin according to the present invention includes a machining step in which the aluminum alloy is machined into an aluminum alloy shape, and the aluminum alloy shape is ammonia, hydrazine, and water-soluble. Contacting with one or more compounds selected from amine-based compounds, and inserting the aluminum alloy shaped article contacted in the contacting step into a molding die, the aluminum alloy shaped article One or more selected from polyalkylene terephthalate, a copolymer mainly composed of the polyalkylene terephthalate, and a thermoplastic resin composition containing the polyalkylene terephthalate as a component on the surface of And a molding process.
[0009]
Hereafter, it demonstrates in detail for every requirement which comprises manufacture of the composite of the aluminum alloy and resin of this invention.
[Aluminum alloy shape]
As the aluminum alloy used as the material of the aluminum alloy shape, 1000-7000 series products which are standardized by JIS (Japanese Industrial Standard), and various aluminum alloys for die casting can be used. The 1000 series is a high-purity aluminum alloy, but the other is an alloy system for various purposes including magnesium, silicon, copper, manganese, etc. in addition to aluminum. For the surface pretreatment step, an alloy containing a relatively large amount of metals other than aluminum is preferably a “pretreatment step I” described later, but this pretreatment step is not necessarily required. In any case, not only high-purity aluminum alloys but also many aluminum alloys that are currently used in the housings of various devices can be used.
[0010]
When resin is bonded by injection molding, the shape of aluminum alloy is made from aluminum alloy lump, plate, bar, etc., plastic processing, sawing, milling, electrical discharge machining, drilling, pressing, grinding, polishing. Etc. are machined into a desired shape alone or in combination. By this machining, an aluminum alloy shape having a shape and structure necessary for an insert for injection molding is processed. The processed aluminum alloy shaped product must have a thick surface such as rust that has been oxidized or hydroxylated on the surface to be bonded. It is necessary to remove by polishing.
[0011]
(I) Surface processing
Although it may also serve as polishing, immediately before the pretreatment step using an aqueous solution described below, the coating layer such as rust on the surface is removed by machining by sandblasting, shot blasting, grinding, barreling, etc. Surface processing is preferable. The surface to be bonded (fixed) to the thermoplastic resin composition to be described later is roughened by these surface treatments, that is, the surface roughness is increased, and the adhesion effect between this surface and the thermoplastic resin composition can be enhanced. preferable.
In addition, this surface processing includes removal of the oil layer on the surface remaining in the metal processing process, and during the storage period of the aluminum alloy shaped material after machining, oxide layer, corrosive layer, etc. generated on the surface It plays an important role such as stripping off and renewing the aluminum alloy surface. As a result, the effect of the next step can be applied uniformly to the entire updated surface. Further, according to the experiments by the present inventors, the blasted aluminum alloy shaped article is the same as the one processed in the next step and its surface condition if stored for about one week under dry air. It was confirmed that there was not much difference.
[0012]
(Ii) Cleaning process
This cleaning step is not necessarily a necessary step in the present invention because the surface processing described above is performed. However, fats and oils and fine dust are attached to the surface of the aluminum alloy shaped product. In particular, the machined surface is provided with a coolant liquid, chips and the like used during machining, and it is preferable to wash them. Although it depends on the kind of dirt, it is preferably carried out by a combination of washing with an organic solvent and washing with water. In the case of a water-soluble organic solvent, for example, acetone, methanol, ethanol, etc., it is easy to remove the solvent by immersing in an organic solvent to remove oily dirt and then washing with water. If there is a strong oily substance, wash with an organic solvent such as benzine or xylene.
Also in this case, it is preferable to wash with water and dry later. Keep the storage period after washing as short as possible. If possible, it is preferable that the cleaning process and the following process (pretreatment process) are continuously performed without taking time. In the case of continuous treatment, it is not necessary to dry after the washing step.
[0013]
[Pretreatment step I]
(I) Alkali etching
When a pretreatment step I described below is performed as a pretreatment for the contact step described later, adhesion between the aluminum alloy shaped article and the thermoplastic resin composition is more effective. This is a process for forming a fine etching surface on the surface of the aluminum alloy. The aluminum alloy shaped article is first immersed in a basic aqueous solution (pH> 7), and then the aluminum alloy shaped article is washed with water. Bases used in basic aqueous solutions include hydroxides of alkali metal hydroxides such as sodium hydroxide (NaOH) and hydroxide (KOH), or soda ash (Na ₂ CO _Three , Anhydrous sodium carbonate), ammonia and the like.
In addition, alkaline earth metal hydroxides (Ca, Sr, Ba, Ra) can be used, but they may be selected from the former group which is practically inexpensive and effective. In the case of using sodium hydroxide, 0.1 to 10% aqueous solution and in the case of using soda ash are preferably 0.1 to 10%, and the immersion time is several minutes at room temperature. After this immersion treatment, it is washed with water. By immersing in a basic aqueous solution, the surface of the aluminum alloy dissolves as aluminate ions while releasing hydrogen, and the surface of the aluminum alloy becomes a fine etched surface.
[0014]
(Ii) Neutralization treatment
Next, it is immersed in an acid aqueous solution and then washed with water. The purpose of using the aqueous acid solution is neutralization. If sodium hydroxide or the like remains on the surface of the aluminum-shaped article in the previous step, it is expected to accelerate the progress of corrosion when used as a product, so neutralization is necessary. In addition, metals dissolved in aluminum alloys such as magnesium, copper, and silicon do not dissolve completely in the pretreatment step of the basic aqueous solution and exist as hydroxides and other compositions near the surface. Therefore, these can be removed by immersing in an acid aqueous solution.
Therefore, any acid aqueous solution may be used as long as the acid aqueous solution meets this purpose. Specifically, dilute nitric acid is preferable, and in a silicon-containing aluminum alloy, it is also preferable to add hydrofluoric acid as a countermeasure against silicon oxide. Nitric acid (HNO _Three ) Concentration is about several percent, and the concentration of hydrofluoric acid (liquid hydrogen fluoride aqueous solution) is preferably 0 to 1.0%. When the concentration of nitric acid is high, the surface of the aluminum alloy approaches the alumite state, and inconvenience is likely to occur in the next process.
[0015]
An immersion time of several minutes is sufficient. In this pre-process, if a substance such as lye (a metal hydroxide or silicon oxide added to aluminum is the main component) adheres to the surface and looks like dirt, this lye If the object melts or peels off, it is judged that this step may be finished. Next, the aluminum alloy shaped article is pulled up from the acid aqueous solution and washed with water.
The neutralization treatment does not necessarily have to be carried out, and even if the neutralization treatment is not performed, the adhesion strength between the aluminum alloy shaped article and the thermoplastic resin composition is practically durable.
[0016]
[Pretreatment process II]
Instead of the above-described pretreatment step I, a pretreatment step II described below may be performed. When this pretreatment step II is performed, adhesion between the aluminum alloy shaped article and the thermoplastic resin composition is effective. First, the aluminum alloy shaped article is immersed in an aqueous solution of a water-soluble reducing agent and washed with water. Water-soluble reducing agents include alkali metal sulfite, alkali metal bisulfite, hydrazine (N ₂ H _Four ), Alkali metal borohydride (eg, sodium borohydride (NaBH _Four )), Aluminum hydride alkali metal (eg, aluminum hydride lithium (LiAlH) _Four ) Etc.) can be used, and sodium sulfite is particularly preferably used. When using sodium sulfite aqueous solution, a density | concentration is about 1 to 5% and immersion time is several minutes-10 minutes at normal temperature.
[0017]
[Contact treatment process]
After the above-described pretreatment step I or II is completed, the following (i) or (ii) contact treatment step is performed.
(I) Aqueous solution immersion method
As a contact treatment method for the surface of an aluminum alloy shaped article, there is an aqueous solution dipping method in which the following compound is dipped in an aqueous solution. The aluminum alloy shaped article is immersed in one or more aqueous solutions selected from ammonia (NH 3), hydrazine (N 2 H 4), and a water-soluble amine compound. The aqueous ammonia solution can be used as it is or after diluting commercially available aqueous ammonia. When hydrazine is used, hydrazine hydrate or hydrazine 60% aqueous solution is commercially available as a raw material and can be used after diluting.
[0018]
As water-soluble amine compounds, lower amines can be used, particularly methylamine (CH _Three NH ₂ ), Dimethylamine ((CH _Three ) ₂ NH), trimethylamine ((CH _Three ) _Three N), ethylamine (C ₂ H _Five NH ₂ ), Diethylamine ((C ₂ H _Five ) ₂ NH), triethylamine ((C ₂ H _Five ) _Three N), ethylenediamine (H ₂ NCH ₂ CH ₂ NH ₂ ), Ethanolamine (monoethanolamine (HOCH ₂ CH ₂ NH ₂ ), Allylamine (CH ₂ CHCH ₂ NH ₂ ), Diethanolamine ((HOCH ₂ CH ₂ ) ₂ NH), etc. are preferred, and these are used by dissolving in water.
[0019]
The concentration of the compound in the aqueous solution used can be about 2 to 30%, and the immersion time is from room temperature to 60 ° C. for several minutes to 30 minutes. For example, in the case of ammonia, the immersion is preferably 15 to 120 minutes at a normal temperature of 10 to 30%. After soaking with these aqueous solutions, they are washed with water and dried.
By immersing the aluminum alloy in an aqueous ammonia solution, the aluminum in the aluminum alloy dissolves as aluminate ions while foaming hydrogen, and the surface becomes a fine etched surface. In the analysis by X-ray electron spectroscopy (XPS) of the surface of the aluminum alloy after being immersed in this aqueous ammonia, washed with water and dried, nitrogen remains on the surface of the aluminum alloy, which is effective for bonding by injection molding. It is estimated that
[0020]
(Ii) Gas contact method
As a contact treatment method for the surface of an aluminum alloy shaped article, there is a gas contact method in which the following compounds are gasified and brought into contact with this gas. However, in this gas contact method, from the viewpoint of securing the adhesion strength between the aluminum alloy shaped article and the thermoplastic resin composition, it is preferable to gas-treat the one subjected to the pretreatment step I.
Aluminum alloy shape is made of ammonia (NH _Three ), Hydrazine (N ₂ H _Four ), Pyridine (C _Five H _Five N) Contact with one or more selected from amine compounds. The purpose of this step is to adsorb these nitrogen-containing compounds to the aluminum alloy shaped product obtained in the previous step. As nitrogen-containing compounds, ammonia, hydrazine, pyridine, methylamine ((CH _Three NH ₂ ), Dimethylamine ((CH _Three ) ₂ NH), trimethylamine ((CH _Three ) _Three N), ethylamine (C ₂ H _Five NH ₂ ), Diethylamine ((C ₂ H _Five ) ₂ NH), triethylamine ((C ₂ H _Five ) _Three N), ethylenediamine (H ₂ NCH ₂ CH ₂ NH ₂ ), Ethanolamine (monoethanolamine (HOCH ₂ CH ₂ NH ₂ ), Allylamine (CH ₂ CHCH ₂ NH ₂ ), Diethanolamine ((HOCH ₂ CH ₂ ) ₂ NH), triethanolamine ((HOCH ₂ CH ₂ ) _Three N), aniline (C ₆ H ₇ N) and other amines are preferred.
[0021]
Ammonia and lower amines with high vapor pressure can pass through the gas (contact), and this process can proceed, and hydrazine and amine compounds with low vapor pressure dissolve in water and contain aluminum alloy. It is also possible to finish the contact by immersing the shaped object, directly immersing it without diluting, or spraying the aqueous solution onto the aluminum alloy shaped object.
In the case of contact with gas, for example, in the case of ammonia, a commercially available ammonia cylinder can be used, or a method of filling a container with half of commercially available ammonia water and passing through the gas layer portion can also be used. The lower amine and the like can be brought into contact with the aluminum alloy by slightly heating the aqueous amine and the like. An aqueous solution is suitable for hydrazine and ethanolamines. The lower amine can be used in an aqueous solution or a toluene solution. Direct immersion in liquefied ammonia or pyridine is also effective, but in the former, the production of industrial equipment becomes large, and in the latter, the treatment of pyridine after treatment is difficult, which is not practical.
Nitrogen compounds belonging to amines in a broad sense used in this step have strong odor and are severe, so in that sense, handling with a dilute solution is most preferable, but if the process is set up in contact with atmospheric ammonia gas, The equipment may not be so cumbersome. The conditions for exposure to atmospheric ammonia gas are preferably several tens of minutes to several days at room temperature. However, the lower amine, hydrazine, aniline and pyridine are preferably immersed in an aqueous solution.
[0022]
(Iii) Storage of aluminum alloy shapes after pretreatment
The aluminum alloy shape after drying is stored under dry air. This storage time should be short, but there is no problem as long as it is within one week at room temperature.
[0023]
[Thermoplastic resin composition]
In the present invention, a thermoplastic resin composition fixed to an aluminum alloy shaped product will be described. The thermoplastic resin composition is one or more selected from polyalkylene terephthalate, a copolymer mainly composed of polyalkylene terephthalate, and a thermoplastic resin composition containing polyalkylene terephthalate as a component on the surface of the aluminum alloy shaped article. Consists of. Polybutylene terephthalate (PBT) is preferred as the polyalkylene terephthalate.
The polymer containing PBT is a polymer of PBT alone, a polymer compound of PBT and polycarbonate (hereinafter referred to as “PC”), a polymer compound of PBT and acrylonitrile-butadiene-styrene resin (hereinafter referred to as “ABS”), PBT. And at least one selected from a polymer compound of polyethylene terephthalate (hereinafter referred to as “PET”) and a polymer compound of PBT and polystyrene (hereinafter referred to as “PS”) can be preferably used.
[0024]
Moreover, a filler is contained in these polymers to improve mechanical properties. The inclusion of the filler is very important particularly from the viewpoint of matching the linear expansion coefficients of the aluminum alloy shaped product and the thermoplastic resin composition. As the filler, glass fiber, carbon fiber, aramid fiber, and other high strength fibers similar to these are preferable.
It is preferable that a filler for improving the physical properties is added to the polymer compound. The filler is composed of one or more selected from known materials such as carbon black, calcium carbonate, calcium silicate, magnesium carbonate, silica, talc, clay, lignin, asbestos, mica, quartz powder, glass sphere and the like. good.
Even when the filler is not included, a very strong force is required to remove the resin molding adhered firmly to the metal. However, when the molded composite is subjected to a temperature cycle test, the adhesive strength of the thermoplastic resin composition system that does not contain the filler is rapidly reduced by repeated cycles. This is presumed to have two causes.
[0025]
One reason is that there is a large difference in linear expansion coefficient between the aluminum alloy shaped product and the thermoplastic resin composition. Pure aluminum has a larger coefficient of linear expansion among metals, but it is still much smaller than thermoplastic resin compositions. The presence of the filler lowers the linear expansion coefficient of the thermoplastic resin composition, and the linear expansion coefficient of the aluminum alloy (2.4 × 10 for pure aluminum). ^-Five ). The linear expansion coefficient can be made very close to that of an aluminum alloy by selecting the type of filler and its content.
The other is the relationship between the cooling shrinkage of the aluminum alloy shaped article after the insert molding and the molding shrinkage of the thermoplastic resin composition. The thermoplastic resin composition containing no filler has a molding shrinkage of about 0.6% even if it is small. On the other hand, the cooling shrinkage of the aluminum alloy, for example, about 0.3% when the thermoplastic resin composition is injected and cooled to about 150 ° C. to room temperature, is smaller than the molding shrinkage rate of the thermoplastic resin composition, and there is a difference. When the thermoplastic resin composition is settled after a long time after releasing from the injection mold, internal distortion occurs at the interface, and the interface breaks with a slight impact and peels off.
[0026]
More specifically, this phenomenon is as follows. Aluminum alloys have a coefficient of thermal expansion, more specifically, a coefficient of linear expansion with respect to temperature changes of 2 to 3 × 10 ^-Five ℃ ^-1 It is. On the other hand, that of polymer compounds containing PBT or PBT is 7-8 × 10 ^-Five ℃ ^-1 It is. In order to reduce the linear expansion coefficient, the filler content in the thermoplastic resin composition is preferably high, and the content ratio is preferably 20% or more, more preferably 30% or more. When PBT or PBT-containing polymer compound contains high-strength fibers or inorganic fillers in a content of 30 to 50%, the linear expansion coefficient is 2 to 3 × 10. ^-Five ℃ ^-1 It almost matches the aluminum.
At this time, the molding shrinkage also decreases. Speaking of molding shrinkage, since the high crystallinity of PBT increases the shrinkage, it can be further reduced by compounding a resin having low crystallinity, such as PET, PC, ABS, PS, etc. However, since the PBT concentration also decreases, the optimum content has not been investigated in detail yet.
[0027]
[Molding / Injection molding]
By preparing an injection mold, opening the mold, inserting an aluminum alloy shape into one of the molds, closing the mold, injecting the thermoplastic resin composition, opening the mold, and releasing the mold. is there. It is the most excellent molding method such as shape flexibility and productivity. In mass production, a robot may be prepared for insert.
Next, injection conditions will be described. Higher mold temperature and injection temperature will give better results, but it will not be forcibly raised, and sufficient adhesive effect can be exhibited under the same conditions as in normal injection molding using the thermoplastic resin composition. . In order to increase the adhesion, it is better to keep in mind that pin gates are used as much as possible in the mold gate structure. In a pin gate, the resin temperature increases instantaneously due to shear friction generated when passing through the resin, and this often produces a good effect. In short, it seems that it is better to devise so that the high-temperature resin melt is in contact with the bonding surface as much as possible within a range that does not hinder smooth molding.
[0028]
[Methods other than molding / injection molding]
Inserting both aluminum alloy shape and thin thermoplastic resin composition into the mold and closing with the other mold and pressing with heating, that is, heat press molding, to obtain an integrated product be able to. Although this method is not suitable for mass production, it may be used depending on the shape. The principle of adhesion is the same as that of the aforementioned injection molding.
In addition, when an integrated product such as a pipe-like material or a plate-like material is required, a method called extrusion molding is used, but the present invention can also be used in this extrusion molding. It is only important that the above-mentioned thermoplastic resin composition is in contact with the surface of the aluminum alloy shaped article that has been treated in the heated and melted state, and theoretically, no molding method should be selected. However, in extrusion molding, the pressure applied between the surface of the molten resin and the aluminum alloy shaped product is significantly lower than that of injection molding or the like. Although the strongest adhesive strength cannot be expected in this respect, there should be a design that can withstand sufficient use in relation to practicality.
[0029]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is an external view of a mobile phone case cover. FIG. 2 is a cross-sectional view of the cellular phone case cover shown in FIG. 1 taken along line II. The case cover 1 is formed from a metal frame 2 made by machining from a plate material made of aluminum alloy. Specifically, the metal frame 2 is made by plastic working with a press machine and a mold driven by the press machine, and further by cutting as necessary.
A rib 3 of a thermoplastic resin composition is integrally fixed to the inner surface of the metal frame 2 for reinforcement with a partition wall. This fixation is injection-molded by a method described later and integrated with the metal frame 2. The thermoplastic resin composition used for injection is as described above. Before the rib 3 is injection-molded, the surface of the metal frame 2 is subjected to the above-mentioned immersion treatment with an aqueous solution of various compounds or contact treatment with a gasified compound.
[0030]
Hereinafter, a method (injection fixation) for fixing the rib 3 and the like by injection molding will be described in detail. After the surface treatment by dipping, the metal frame 2 described above is taken out as much as possible within one week of storage start and inserted into an injection mold for injecting the ribs 3. FIG. 3 is a cross-sectional view of an injection mold in which the surface of the metal frame 2 is filled with a thermoplastic resin composition by injection molding. The pretreated metal frame 2 is inserted into the cavity of the movable side template 10.
The movable side template 10 is closed with the metal frame 2 inserted into the cavity. The cavity 11 is a space formed by the metal frame 2, the movable mold plate 10, and the fixed mold plate 13 with the movable mold plate 10 and the fixed mold plate 13 closed. Molten resin constituting the rib 3 is supplied to the cavity 11 via the runner 15 and the gate 14 to mold the rib 3. The housing of the completed case cover 1 has a metal frame 2 and a rib 3 made of a thermoplastic resin composition joined together, making use of the characteristics of metal in terms of strength and appearance, Moreover, the shape and structure inside the housing can also be complicated.
[0031]
[Experimental example]
Hereinafter, in order to confirm the embodiment of the present invention by experiment, the following simple experiment was performed.
(I) Experimental example 1 (immersion in aqueous solution)
A commercially available 1 mm thick A1100 (Japanese Industrial Standard (JIS)) aluminum alloy plate was purchased. Cut into 100 rectangular pieces of 20 mm × 50 mm. This aluminum piece was affixed to a rubber sheet with double-sided tape and placed in a blasting device (not shown). The air pulse time was set so that the polishing amount was about 5 μm, and air blasting was performed. Take out from the blasting device and leave on average within 5 hours, soak it in 4 liters of ethanol for 10 minutes while applying ultrasonic waves, soak it in 4 liters of ion-exchanged water, stir it in a plastic colander, and then add ion-exchanged water 2 Washed with liters and dried with high pressure air.
[0032]
Next, 0.5 liters of 28% ammonia water was prepared in a polyethylene beaker, and the aluminum piece was dipped. This was pulled up after 25 minutes and thoroughly washed with ion-exchanged water. Furthermore, after being immersed in acetone filled in a beaker for several seconds, high-pressure air was blown to dry, and the product was stored in a storage box filled with dry air.
Two days later, the aluminum piece was taken out from the storage box, picked up with gloves so as not to adhere oil, etc., and inserted into an injection mold. The mold was closed, and PBT / PET resin (PBT about 70% and PET about 30%, manufactured by Mitsubishi Rayon Co., Ltd.) containing 20% glass fiber and 20% ultrafine talc was injected, as shown in FIG. An integrated composite was obtained.
[0033]
The rectangular base shown in FIG. 4 is a plate-shaped metal piece 21. This is the same thickness as the aluminum piece obtained earlier, and is a 20 mm × 50 mm rectangular shape. A resin composition is injected from two pin gates 22 and 23 to form a boss-shaped object 24 and a rib-shaped object 25. The boss-shaped object 24 has a circular shape with an adhesive surface of 8 mm in diameter, and the rib-shaped object 25 has a rectangular shape with an adhesive surface of 8 mm × 25 mm. Both the boss-shaped object 24 and the rib-shaped object 25 have a height of 8 mm, and the boss-shaped object 24 has a hole with a diameter of 2 mm at the center so that a threaded measuring end for torque measurement can be screwed in.
The mold temperature was 100 ° C., and the final partial temperature of the heating cylinder of the injection molding machine and the nozzle temperature were 270 ° C. The molded article was left in the room for one week after molding, and then the adhesion was inspected. Press the aluminum plate part on the desk and push the tip of the boss shaped object 24 and the rib shaped object 25 strongly with the thumb in the horizontal method to peel off the resin part. I couldn't. This simple test was performed on 10 molded articles, all of which were the same.
[0034]
With respect to a total of 70 pieces including 10 pieces, the resin part of the rib-shaped object 25 was gripped from above (with the pliers in the vertical direction) with pliers, and the pliers were tilted as they were to remove the rib-shaped object 25. However, the bonded surfaces of 70 pieces were not peeled off at all, and the rib-shaped object 25 was broken from the middle. Similarly, when the boss-shaped object 24 was sandwiched and bent with pliers, 10 pieces could be peeled off from the aluminum plate, but a small amount of resin residue remained on the aluminum surface to which the boss-shaped object 24 was adhered. The material was destroyed. The remaining 60 pieces could not be peeled off, and the boss-shaped object 24 was broken in the middle.
Furthermore, about another ten pieces, the measurement end with a thread was thrust into the hole in the boss-shaped object 24, and the torque measuring device was turned. Attempts were made to measure the torque when the boss-shaped object 24 was peeled off, but in all cases, the hole on the resin side was shaved around the torque exceeding about 200 Ncm and the boss-shaped object 24 was not peeled off.
[0035]
Furthermore, another 10 pieces were taken and placed on a metal pan, and a temperature cycle test between 85 ° C. and −40 ° C. was performed. Raise the temperature from room temperature at + 0.7 ° C / min to 85 ° C for 2 hours, then return to room temperature (25 ° C at the time of experiment) at a rate of 0.7 ° C / min. Cooled to -20 ° C at speed. This is a temperature cycle test in which the temperature is set at −40 ° C. for 2 hours, this time the temperature is raised at + 0.7 ° C./minute, the temperature is returned to room temperature, and the temperature is raised again after 1 hour. After 100 cycles, the test was performed using the same pliers and torque measuring instrument as described above. The results were the same as the test results without the temperature cycle test.
Further, a high temperature and high humidity test was conducted on another 10 pieces. Specifically, it was allowed to stand for 24 hours under conditions of 85 ° C. and 60% humidity, returned to room temperature over 1 hour, and then tested using the same pliers and torque measuring instrument as in the previous period. The results were the same as the test results without the high temperature and high humidity test. When viewed as a whole, surprisingly stable results were obtained as a destructive test of the adhesive.
The reason why this is possible is that the aluminum alloy was contact-treated with ammonia. It is presumed that the surface of the aluminum alloy has been changed to the parent PBT surface by this treatment.
[0036]
(Ii) Experimental example 2
A commercially available 1 mm thick A5052 (Japanese Industrial Standard (JIS)) aluminum alloy plate was purchased. Cut into 50 rectangular pieces of 20 mm × 50 mm. This was washed in the same manner as in Experimental Example 1. Next, 500 g of a 1% aqueous sodium hydroxide solution was prepared in a polyethylene beaker, and the aluminum pieces described above were immersed therein. After 2 minutes, it was lifted and thoroughly washed with ion exchange water.
Next, 500 cc of an aqueous solution containing 1% nitric acid and 0.2% hydrofluoric acid was prepared in a polyethylene beaker, and the aluminum piece was neutralized by dipping for 1 minute. It was pulled up and thoroughly washed with ion exchange water. Next, 500 g of a 1% aqueous methylamine solution was prepared in a polyethylene beaker, and the aluminum piece was dipped for 1 minute, pulled up, and thoroughly washed with ion-exchanged water.
[0037]
Furthermore, after being immersed in acetone filled in a beaker for several seconds, high-pressure air was blown to dry, and the product was stored in a storage box filled with dry air. Two days later, the aluminum piece was taken out of the storage box, picked up with gloves so that oil and the like would not adhere, and inserted into an injection mold. Thereafter, molding was performed in the same manner as in Experimental Example 1. About 10 of the obtained integrated products, the aluminum plate part was pressed on the desk and the tips of the boss shaped object 24 and the rib shaped object 25 were strongly pressed with the thumb in the horizontal method to remove the resin part. I couldn't remove it even if I pushed it until my finger was almost scratched.
[0038]
With respect to a total of 50 pieces including the 10 pieces, the resin part of the rib-shaped object 25 was grasped from above (with the pliers in the vertical direction) with pliers, and the pliers were tilted as they were to remove the rib-shaped object 25. However, the adhesive surfaces of all 50 pieces were not peeled off, and the rib-shaped object 25 was broken from the middle. Similarly, when the boss-shaped object 24 was sandwiched and bent by pliers, seven pieces could be peeled off from the aluminum plate, but a small amount of resin residue remained on the aluminum surface to which the boss-shaped object 24 was adhered. The material was destroyed. The remaining 43 pieces could not be peeled off, and the boss-shaped object 24 broke along the way.
In order to firmly attach the thermoplastic resin composition to the aluminum alloy, a method in which chemical etching or immersion treatment in a base / acid aqueous solution is added before contact treatment with an amine compound can be used. I was able to confirm.
[0039]
(Iii) Experimental example 3 (gas contact method)
In Experimental Example 2 described above, the aluminum piece was treated with an aqueous sodium hydroxide solution and then neutralized with hydrofluoric acid. After this neutralization treatment, aluminum pieces were immersed in 28% ammonia water in Experimental Example 1, but instead, they were contacted with ammonia gas by the following method. The above-mentioned aluminum pieces were placed in a double large polyethylene bag filled with 30 liters of ammonia so as not to overlap completely, and were allowed to stand while supplying a small amount of ammonia gas.
This was taken out after 48 hours, blown with high-pressure air, and then stored in a storage box filled with dry air. Except for this treatment, substantially the same treatment and strength test as in Experimental Example 1 were performed. This adhesive strength was substantially the same as that of Experimental Example 1.
[0040]
(Iv) Experimental example 4
A commercially available 1 mm thick A1100 (Japanese Industrial Standard (JIS)) aluminum alloy plate was purchased. Cut into 50 rectangular pieces of 20 mm × 50 mm. This was washed in the same manner as in Experimental Example 1. Next, 500 g of 5% strength sodium sulfite aqueous solution was prepared in a polyethylene beaker, and the aluminum piece was dipped. After 10 minutes, it was lifted and thoroughly washed with ion exchange water.
Next, 500 g of a 1% aqueous ethylenediamine solution was prepared in a polyethylene beaker, and the aluminum piece was dipped for 1 minute, pulled up, and sufficiently washed with ion-exchanged water. Furthermore, after being immersed in acetone filled in a beaker for several seconds, high-pressure air was blown to dry, and the product was stored in a storage box filled with dry air.
[0041]
Two days later, the aluminum piece was taken out of the storage box, picked up with gloves so that oil and the like would not adhere, and inserted into an injection mold. Thereafter, molding was performed in the same manner as in Experimental Example 1. About 10 of the obtained integrated objects, the aluminum plate part was pressed on the desk and the tips of the boss-shaped object 24 and the rib-shaped object 25 were pressed with the thumb in the horizontal direction to remove the resin part. I couldn't remove it even if I pushed it until my finger was almost scratched.
[0042]
With respect to a total of 50 pieces including the 10 pieces, the resin part of the rib-shaped object 25 was grasped from above (with the pliers in the vertical direction) with pliers, and the pliers were tilted as they were to remove the rib-shaped object 25. However, the adhesive surfaces of all 50 pieces were not peeled off, and the rib-shaped object 25 was broken from the middle. Similarly, when the boss-shaped object 24 was sandwiched and bent with pliers, 12 pieces could be peeled off from the aluminum plate, but a small amount of small resin residue was left on the aluminum surface to which the boss-shaped object 24 was adhered. The remaining material was destroyed. The remaining 38 pieces could not be peeled off, and the boss-shaped object 24 was broken in the middle.
[0043]
(V) Experimental Example 5
A commercially available 1 mm thick A5052 (Japanese Industrial Standard (JIS)) aluminum alloy plate was purchased. Cut into 50 rectangular pieces of 20 mm × 50 mm. This was washed in the same manner as in Experimental Example 1. Next, 500 g of a 1% aqueous sodium hydroxide solution was prepared in a polyethylene beaker, and the aluminum pieces described above were immersed therein. After 2 minutes, it was lifted and thoroughly washed with ion exchange water.
Next, 500 cc of 1% concentration nitric acid was prepared in a polyethylene beaker, and the above-mentioned aluminum piece was immersed for 1 minute to neutralize. It was pulled up and thoroughly washed with ion exchange water. Next, 500 g of a 5% hydrated hydrazine aqueous solution was prepared in a polyethylene beaker, heated to 50 ° C., the aluminum piece was immersed for 2 minutes, pulled up, and thoroughly washed with ion-exchanged water. .
[0044]
Furthermore, it moved to the warm air dryer, dried over 70 minutes at 70 degreeC, and accommodated in the storage box filled with dry air. Two days later, the aluminum piece was taken out of the storage box, picked up with gloves so that oil and the like would not adhere, and inserted into an injection mold. Thereafter, molding was performed in the same manner as in Experimental Example 1. About 10 of the obtained integrated objects, the aluminum plate part was pressed on the desk and the tip of the boss shaped object 24 and the rib shaped object 25 was pressed strongly with the thumb in the horizontal method to remove the resin part. All could not be removed by pushing until the finger was almost scratched.
With respect to a total of 50 pieces including the 10 pieces, the resin part of the rib-shaped object 25 was grasped from above (with the pliers in the vertical direction) with pliers, and the pliers were tilted as they were to remove the rib-shaped object 25. However, the adhesive surfaces of all 50 pieces were not peeled off, and the rib-shaped object 25 was broken from the middle. Similarly, when the boss-shaped object 24 was sandwiched and bent by pliers, seven pieces could be peeled off from the aluminum plate, but a small amount of resin residue remained on the aluminum surface to which the boss-shaped object 24 was adhered. The material was destroyed. The remaining 43 pieces could not be peeled off, and the boss-shaped object 24 broke along the way.
[0045]
[Application field of the present invention]
Fields of application of the present invention are various electronic devices for mobile devices, household electrical appliances, medical devices, automobile bodies, parts mounted on vehicles, parts for building materials, other structural parts for various machines, various interior / exterior parts Etc. can be used.
[0046]
【The invention's effect】
The aluminum alloy / resin composite of the present invention and the method for producing the same are obtained by treating the surface of the aluminum alloy so that the thermoplastic resin composition and the aluminum alloy shaped product are not easily peeled off. We can make housings, parts, structures, etc. for various devices that have no problems in terms of structure and mechanical strength. Furthermore, weight reduction and equipment manufacturing processes for housings, parts, structures, etc. of electronic devices, etc. The effect that it can be useful for simplification of.
[Brief description of the drawings]
FIG. 1 is an external view of a mobile phone case cover.
FIG. 2 is a cross-sectional view of the mobile phone case cover shown in FIG. 1 taken along line II.
FIG. 3 is a cross-sectional view of an injection mold in which the surface of a metal frame is filled with a thermoplastic resin composition by injection molding.
FIG. 4 is a test piece of a composite of an aluminum alloy and a resin.
[Explanation of symbols]
1 ... Case cover
2 ... Metal frame
3 ... Ribs
10 ... Moveable side template
13 ... Fixed side template

Claims (14)

An aluminum alloy shaped article that has undergone a dipping step of dipping in a 50% aqueous solution of 5% hydrated hydrazine for 2 minutes;
At least one selected from polybutylene terephthalate , a copolymer mainly composed of polybutylene terephthalate, and a thermoplastic resin composition containing polybutylene terephthalate as a component on the surface of the aluminum alloy shaped article is injection molded. A composite of aluminum alloy and resin characterized by being adhered by In the aluminum alloy and resin composite according to claim 1 ,
The aluminum alloy shaped article has been subjected to a neutralization treatment step in which it is immersed in an aqueous sodium hydroxide solution and then in an aqueous nitric acid solution before the contacting step. body. In the aluminum alloy and resin composite according to claim 1 ,
The polymer of polybutylene terephthalate is a polymer of polybutylene terephthalate alone, a polymer compound of polybutylene terephthalate and polycarbonate, a polymer compound of polybutylene terephthalate and acrylonitrile butadiene styrene resin, a polymer compound of polybutylene terephthalate and polyethylene terephthalate, and poly A composite of an aluminum alloy and a resin, which is at least one selected from a polymer compound of butylene terephthalate and polystyrene. In the aluminum alloy and resin composite according to claim 3 ,
A filler for improving physical properties is added to the polymer. A composite of aluminum alloy and resin. In the aluminum alloy and resin composite according to claim 3 ,
A high-strength fiber is added to the polymer to increase mechanical strength. A composite of aluminum alloy and resin. In the aluminum alloy and resin composite according to claim 4 ,
The filler comprises one or more selected from carbon black, calcium carbonate, calcium silicate, magnesium carbonate, silica, talc, clay, lignin, asbestos, mica, quartz powder, and glass spheres. A composite of aluminum alloy and resin. In the aluminum alloy and resin composite according to claim 5 ,
The high-strength fiber comprises at least one selected from glass fiber, carbon fiber, and aramid fiber. A composite of aluminum alloy and resin. A method for producing a composite of an aluminum alloy and a thermoplastic resin composition,
Machining the aluminum alloy to form an aluminum alloy shape,
An immersion step of immersing in a 50% aqueous solution of 5% hydrated hydrazine for 2 minutes ;
The aluminum alloy shaped article that has been dipped in the dipping step is inserted into a molding die, and polybutylene terephthalate, a copolymer mainly composed of the polybutylene terephthalate, is formed on the surface of the aluminum alloy shaped article. And a molding process in which at least one selected from the group consisting of a polybutylene terephthalate and a thermoplastic resin composition containing the polybutylene terephthalate as a component is integrated by injection molding. A method for producing the composite. A method for producing a composite of an aluminum alloy according to claim 8 and a thermoplastic resin composition,
Between the processing step and the immersion step,
A first immersing step of immersing the aluminum alloy shaped article in an aqueous sodium hydroxide solution ;
The aluminum alloy shaped article and the resin comprising: a second immersing step of immersing in an aqueous nitric acid solution to neutralize the aluminum alloy shaped article subjected to the immersion treatment in the first immersing process. A method for producing the composite. In the manufacturing method of the composite of the aluminum alloy and resin of Claim 8 ,
The polymer of polybutylene terephthalate is a polymer of polybutylene terephthalate alone, a polymer compound of polybutene terephthalate and polycarbonate, a polymer compound of polybutylene terephthalate and acrylonitrile butadiene styrene resin, a polymer compound of polybutylene terephthalate and polyethylene terephthalate, and poly A method for producing a composite of an aluminum alloy and a resin, wherein the composite is one or more selected from a polymer compound of butylene terephthalate and polystyrene. In the manufacturing method of the aluminum alloy and resin composite according to claim 10 ,
A high-strength fiber is added to the polymer in order to increase mechanical strength. A method for producing a composite of an aluminum alloy and a resin. In the manufacturing method of the aluminum alloy and resin composite according to claim 11 ,
The said high-strength fiber consists of 1 or more types selected from glass fiber, carbon fiber, and an aramid fiber. The manufacturing method of the composite of aluminum alloy and resin characterized by the above-mentioned. In the manufacturing method of the aluminum alloy and resin composite according to claim 10 ,
A filler for improving physical properties is added to the polymer. A method for producing a composite of an aluminum alloy and a resin. In the manufacture of the aluminum alloy and resin composite according to claim 13 ,
The filler is composed of at least one selected from carbon black, calcium carbonate, calcium silicate, magnesium carbonate, silica, talc, clay, lignin, asbestos, mica, quartz powder, and glass spheres. A method for producing a composite of an aluminum alloy and a resin.

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