JP4202015B2 - Metal-resin composite and method for producing the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a metal / resin composite used for a housing of an electronic device incorporating an IC or the like, a structural component, and the like, and a method for manufacturing the same. More specifically, regarding the structure of a structure in which a metal frame made by sheet metal processing, pressing, cutting, notching, etc. and a thermoplastic resin composition are integrated, various industrial control devices, household appliances, The present invention relates to a metal-resin composite used for communication devices such as mobile phones, medical devices, cases for mounting on vehicles and building materials, structural parts, exterior parts, and the like, and a method for manufacturing the same.
[0002]
[Prior art]
Technology for integrating metal and synthetic resin is required from a wide range of fields such as parts production for automobiles, home appliances, industrial equipment, etc., and many adhesives have been developed for this purpose. Among them, there are very good adhesives. For example, adhesives that function at room temperature or by heating are used for joining metal and synthetic resin, and this method is now a common technique. .
[0003]
However, it has been studied in the past whether there is a more rational joining method that does not use an adhesive. As far as the present inventors know, a method for integrating a high-strength engineering resin without using an adhesive with light metals such as aluminum, magnesium and alloys thereof, or iron alloys such as stainless steel. It is not put into practical use at present. The present inventors have made extensive research and development on these.
[0004]
The reason why the inventors proceed with this development is as follows. That is, the recent development and market expansion of portable electronic devices such as mobile phones, portable personal computers, PDAs, etc. are demanding a lighter and more durable structure with a superior appearance, made of light alloys such as aluminum and magnesium, and thin stainless steel A combination of a sheet-made exterior portion and a chassis made of a high-strength resin, which is completely different from the material, bears this demand, and a rational means for joining them is required.
[0005]
In addition, since the electromagnetic wave disturbance has entered the environment of not only business operators but also general consumers in the IT era, it is necessary to shield electromagnetic waves emitted by electric devices and electronic devices as much as possible. Aluminum alloy is a preferable shielding material because it is a metal and has high malleability and is easy to process. On the other hand, the polybutylene terephthalate (PBT) resin, which is mainly handled in the present invention, is excellent in both heat resistance and mechanical strength. Therefore, if a method for joining the two by an easy means is found, it can contribute to this field. .
[0006]
In addition, the use of the composite of metal and resin is not limited to portable electronic devices aiming at weight reduction and electromagnetic wave shielding as described above, and injects a thermoplastic resin composition excellent in metal and heat resistance and strength, If it can be firmly bonded by hot pressing or other thermoforming processes, a surprisingly wide range of applications can be expected. That is, if it is used for a case or chassis in a stationary electronic / electric machine or a general machine (for example, a television, a personal computer, a sewing machine, etc.), there are significant advantages in terms of weight reduction and design. In addition, if the technology advances to the point where strength reduction due to temperature cycling in a metal-resin composite can be completely suppressed, it can be used for a wide variety of machine parts. Furthermore, if the application proceeds until the composite of the metal and the resin can be used for a mobile machine such as an automobile or an aircraft, it will be the most wonderful application that can be expected.
[0007]
The insert molding method is considered first as the easiest joining means that meets the above-mentioned purpose in consideration of cost and productivity. That is, a metal frame is formed into a desired shape by bending, cutting, drawing and other pressing methods, milling and other cutting methods and notching processing, and the metal mold is formed on an injection mold. This is a method of injecting a molten thermoplastic resin composition after inserting a frame.
[0008]
An invention that can be adapted to this means is disclosed and proposed in Japanese Patent Publication No. 5-51671. This proposed invention is similar to electroplating by immersing a metal plate such as copper, brass, iron, stainless steel, nickel, zinc, and aluminum in an aqueous solution in which an alkali salt or amine ammonium salt of triazine thiol is dissolved. An electrochemical treatment is performed based on the idea (in this invention, it is referred to as “organic plating”).
[0009]
It has been shown that when this “organic plating” treatment is performed, an organic layer is firmly deposited on the metal surface and the surface becomes an organic layer. It is disclosed that the metal and the plastic stock are firmly bonded if they are repeatedly pressed with a hot plate.
[0010]
In order to follow up the proposed invention, the inventors used an aluminum alloy as a metal to be used and injected various synthetic resins. In the follow-up experiment of the present inventors, when nylon 12 was used for this synthetic resin, a high aluminum / resin adhesion (heat fusion) strength could be confirmed. Therefore, the mass production by insert injection molding in which the molded aluminum metal is inserted and nylon 12 series resin is injected into this mold, that is, commercialization, was examined in detail.
[0011]
However, as a result of examination, it was not so favorable. As a problem, for example, before the “organic plating” described above, pretreatment is necessary for removal of oil and fat on the aluminum surface, removal of metal oxide, or activation. If this pre-treatment is performed in a stable environment and under strict conditions, favorable adhesive strength cannot be obtained, the conditions for applying "organic plating" are delicate, and management during mass production is not easy, and resin is injected. When the mold temperature is not set to a very high level, a preferable adhesive force cannot be obtained. When the mold temperature is increased, the molding cycle becomes longer, and depending on the shape, the molded product may be deformed when released from the mold. It was found that there were various problems such as.
[0012]
[Problems to be solved by the invention]
The proposed technology has not yet been commercialized by other companies in the same industry, and the present inventors have also left off the commercialization. However, if a practical method can be established, it can be applied to various fields and the market is expected to be large. As the bonding method, we chose the adhesion by injection of engineering resin with metal piece insert, the so-called injection molding method, and continued research and development with a focus on the modification of the surface layer on the metal side.
[0013]
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 provide a metal / resin composite used for a housing of an electronic device and the like and a method for producing the same by firmly integrating a metal frame and a thermoplastic resin composition.
Another object of the present invention is to provide a composite in which a metal and a resin used for a casing of an electronic device and the like are firmly integrated by an injection molding method with high productivity and mass productivity, and a method for manufacturing the same. is there.
Still another object of the present invention is to firmly integrate a metal and a resin used for a housing of an electronic device, etc., using a metal frame having high electromagnetic shielding properties and having a moldability of a thermoplastic resin composition. And providing a method for producing the same.
[0014]
[Means for Solving the Problems]
The present invention adopts the following means in order to achieve the object. The metal / resin composite of the present invention has a side part standing from the bottom part and a projection part protruding from the side part and bendable with respect to the side part. A metal metal frame whose surface is treated with an aqueous compound (or ammonia) solution, and attached to the surface of the metal frame in a space surrounded by the bottom, the side, and the bent projection, One or more types selected from the group consisting of alkylene terephthalate, a copolymer mainly composed of the polyalkylene terephthalate, or a thermoplastic resin composition containing the polyalkylene terephthalate as a component.
[0015]
[Metal frame]
As the metal material of the metal frame, an aluminum alloy can be preferably used. Aluminum alloys are preferred among metals because they have a relatively large linear expansion coefficient, are easily matched to those of the resin composition, and are excellent in malleability and workability. This metal frame is cut, cut, bent, drawn and polished by various metal processing methods such as sawing, milling, drilling, pressing, grinding, polishing, and notching. Thus, a shape and a structure necessary for an insert in injection molding are obtained.
[0016]
The metal frame here has a side part standing from the bottom part and a projection part protruding from the side part and bendable with respect to the side part, and the projection part is bent. -A structure, for example, a metal plate with notched edges and protrusions is bent to form a rectangular bottom, four sides standing upright from four corners of the bottom, and each side The opening container is formed with four protrusions that are bent in parallel with the bottom so as to cover the four corners intersecting each other. As described above, the metal frame can be easily configured by bending the metal plate with the side portions and the protrusions notched, so that productivity and mass productivity can be improved. Further, by forming the protrusions at the corners of the metal frame where the sides intersect, the metal frame and the thermoplastic resin composition can be firmly integrated at the corners. In addition, the metal frame and the thermoplastic resin composition can be more firmly integrated by forming a biting portion that bites into the thermoplastic resin composition at the tip of the protrusion.
[0017]
[Cutting / Polishing]
It is preferable that the metal frame has been subjected to a physical surface renewal operation by cutting or polishing before the step of treating the surface with a water-soluble amine compound (or ammonia) aqueous solution. The cutting and polishing referred to in the present invention refers to further cutting and / or polishing after performing the necessary shape formation by the various metal processing methods described above. If the final process for forming the required shape is cutting or polishing, and the storage after the end of the cutting or polishing is preferable as described later, cutting and / or polishing in this section can be omitted. . The purpose of this step is to physically renew the metal surface before contacting with an aqueous solution of a water-soluble amine compound (or ammonia) so that the effect of the next step is as uniform as possible over the entire surface. This is because the metal surface is usually covered with an oxide or hydroxide, but an object that has been stored for a long period of time becomes thicker as the oxide layer penetrates into the interior, and when it becomes severe, it becomes a rust surface.
[0018]
As an example of an aluminum alloy, commercially available aluminum plates have been baptized by pressure and heat during the rolling process, and some surfaces have been lightly acid-treated to improve weather resistance. The oxide layer is quite thick. It is assumed that this aluminum plate is polished with a strong flow of compressed air mixed with fine sand particles (blast treatment). By this polishing, the surface covered with the oxide is peeled off, and the metal aluminum atoms are exposed for a moment, and at the next moment, it is oxidized by oxygen in the air to form an oxide film. The thickness is thin. The metal frame after polishing does not change as soon as it is stored under dry air. However, under high temperature and high humidity, the oxide and hydroxide increase, and the original state (state of the surface before polishing) approaches quickly. Therefore, it is important for the storage after this step to confirm the environment such as the humidity temperature and to shorten the period.
[0019]
This process will be specifically described. Cutting is literally cutting. Polishing is preferably performed using sandpaper, a powder abrasive, an abrasive paste, or the like. Polishing called sand blasting, air blasting, or blasting using a sand grain or fine abrasive and compressed air or compressed nitrogen is more preferred. For the purpose, it is better that the temperature does not rise at the time of polishing and the moisture and moisture that coexist is small. Therefore, blasting is preferable for commercialization on the premise of mass production. The preservation of the metal frame after this step is as described above. According to the present inventors, the shape of an aluminum alloy that has been subjected to blasting did not appear to be much different from that of the next process when stored for about one week in dry air.
[0020]
[Chemical etching]
The metal frame is preferably subjected to the physical surface renewal operation by cutting or polishing as described above before the step of treating the surface with a water-soluble amine compound (or ammonia) aqueous solution. It is preferable that chemical etching is performed. Chemical etching is a short-time immersion in an aqueous chemical solution in which the metal species used dissolves. In the case of an aluminum alloy, for example, when immersed in an aqueous sodium hydroxide solution, the surface dissolves and a fine uneven surface is generated. In this case, it is preferable to wash with water after immersion, wash with a thin acid aqueous solution, and wash with sufficient water so that corrosion does not proceed due to sodium hydroxide remaining on the later day. It is considered that the contact area with the resin is expanded by chemical etching, and the generated fine irregularities produce a strong adhesive force.
[0021]
However, this chemical etching process and the physical surface renewal operation described above are not necessary conditions in the present invention, and the finally obtained metal-resin composite has the integrated strength necessary for its use. If it is, it is preferable to remove the process which is excessive and costly.
[0022]
[Washing]
The metal frame is preferably washed before the immersion treatment in the most important water-soluble amine compound (or ammonia) aqueous solution. Of course, when chemical etching is performed, since the final process is washing with water, this process can also be performed. Therefore, other cases will be described. Generally, the surface of metal workpieces has processing oil and finger grease, and the metal frame after blasting is also washed with sand, fine oil droplets and dirt. It is important to do. This washing is preferably performed by a combination of washing with an organic solvent and washing with water. For example, it is immersed in a water-soluble organic solvent such as acetone or ethanol to remove oily dirt, washed with water, and air-dried with forced air. If a strong oily substance adheres, wash with an organic solvent such as benzine or xylene, then wash with water and dry with forced air.
[0023]
The storage period after washing should be as short as possible. If possible, the washing step and the next step are preferably carried out successively. When processing continuously, the drying process at the end of this process can be simplified or omitted. When storage is necessary until the next step, the product is dried and then stored at least under dry air, and the temperature is preferably room temperature or lower. In the case of aluminum alloy shaped product, it was summer, but after washing and drying, it was stored in dry air at room temperature for 24 hours and sent to the next process. However, there was a significant difference from the product that was sent to the next process immediately. There wasn't. Although the present inventors have never implemented it, it is theoretically possible to extend the effective period if it is stored under dry nitrogen and at a low temperature.
[0024]
[Surface treatment of metal frame]
Next, a specific method of surface treatment of the metal frame with a water-soluble amine compound (or ammonia) aqueous solution will be described. The water-soluble amine compound used in the present invention refers to hydrazine and its derivatives, lower amine compounds, pyridine, aniline and the like. As the lower amine, readily water-soluble lower amines such as methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine and triethylamine can be particularly preferably used. Depending on the type of these water-soluble amine compounds, it is dissolved in water so as to have a concentration of several% to several tens of%, and the metal frame after washing is immersed in it for a certain time.
[0025]
For example, a specific method for preparing a hydrazine treatment liquid is as follows. Commercially available hydrazine hydrate or 60% hydrazine aqueous solution can be used as a raw material. This is obtained and diluted with water to give a hydrazine concentration of 1 to 5%, preferably 2 to 4%. Although depending on the aluminum alloy used, when an aluminum alloy of A1050 standard (Japanese Industrial Standard (JIS)) was used, good results were obtained when immersed for 60 to 120 seconds with a hydrazine concentration of the hydrazine aqueous solution being 3%.
[0026]
In the case of using ammonia water, for example, 25 to 28% of commercially available ammonia water as it is, finally good results were obtained by immersing in A1100 aluminum alloy treatment for 10 to 30 minutes. The optimum treatment conditions differ depending on the amine compound (or ammonia) used and the corresponding metal species. As for the aluminum alloy, it seems that the treatment time can be shortened by increasing the concentration of the water-soluble amine compound, but if it is short, the stability of the process is impaired. On the other hand, when the concentration is lowered, the immersion time for exerting the effect becomes longer.
[0027]
The treated metal frame is preferably stored under dry air so that it is not exposed to moisture. Confirmation experiments have not been conducted until it should be stored under dry nitrogen. In the case of an aluminum alloy, if it was stored for up to one week, it was confirmed that the effect continued even if stored at room temperature in dry air.
[0028]
[Thermoplastic resin composition]
Next, the thermoplastic resin composition to be used will be described. The thermoplastic resin composition is at least one selected from polyalkylene terephthalate, a copolymer mainly composed of polyalkylene terephthalate, or a thermoplastic resin composition containing polyalkylene terephthalate as a component. Here, the polyalkylene terephthalate is preferably PBT. The thermoplastic resin composition includes a polymer of PBT alone, a polymer compound of PBT and polycarbonate (PC), a polymer compound of PBT and acrylonitrile / butadiene / styrene resin (ABS resin), or a polymer of PBT and polyethylene terephthalate (PET). One or more selected from compounds are preferred.
[0029]
Moreover, the inclusion of a filler in the resin composition is very preferable. The reason is the difference in the linear expansion coefficient between the metal material and the resin material. Generally speaking, the coefficient of linear expansion of a metal is much smaller than that of a thermoplastic resin, and the lengths of expansion and contraction when heated or cooled are different from each other. If the linear thermal expansion coefficients of the two are different, a deviation stress is inevitably generated due to a temperature change in the integrated product, that is, the bonded surface of the composite. In the case of adhesion by an adhesive, an elastic adhesive is used to absorb the difference in thermal expansion and contraction between the two, but in the present invention, highly rigid materials are directly bonded and there is no escape. Therefore, a device for absorbing and mitigating the deviation stress at the time of temperature change is necessary. A large amount of filler mixed into the resin is a solution.
[0030]
As the filler, glass fiber, carbon fiber, aramid fiber, and other high strength fibers similar to these are preferable. Further, a thermoplastic resin composition containing a calcium carbonate, magnesium carbonate, silica, talc, clay, pulverized product of carbon fiber or aramid fiber, and other similar inorganic fillers for resin filling is very preferable. Even when the filler is not included, a very strong force is required to firmly adhere and peel off the thermoplastic resin composition adhered to the metal. However, when the molded composite is subjected to a temperature cycle test, in a resin system that does not contain a filler, the adhesive strength often decreases rapidly by repeated cycles. In detail, this has two causes.
[0031]
One reason is that there is a large difference between the metal frame and the thermoplastic resin composition in terms of linear expansion coefficient. Aluminum has a larger coefficient of linear expansion among metals, but it is still much smaller than that of a thermoplastic resin composition. The presence of the filler lowers the linear expansion coefficient of the thermoplastic resin composition, and the thermal expansion coefficient of the aluminum alloy (2.386 × 10 2 for pure aluminum). ^-Five ). If the type and content of the filler are selected, it is estimated that the linear expansion coefficient can be made to be a value close to that of an aluminum alloy.
[0032]
The other is the relationship between the cooling shrinkage of the metal frame after insert molding and the molding shrinkage of the thermoplastic resin composition. The molding shrinkage rate of the thermoplastic resin composition containing no filler is about 0.6% even if it is small. On the other hand, the cooling shrinkage of the aluminum alloy is, for example, about 0.2% as it cools from the time of injection to room temperature by about 100 ° C., which is much smaller than the molding shrinkage of the thermoplastic resin composition, and there is a difference between the two. Therefore, when the composite is released from the mold and time passes and the resin settles down, internal strain occurs at the interface between the metal and the resin, and the interface breaks down due to a slight impact and peels off.
[0033]
As described above, aluminum has a large coefficient of thermal expansion among metals and is preferable as a metal species to be used. Nevertheless, the coefficient of linear expansion is 2-3 × 10 for aluminum alloys. ^-Five ℃ ^-1 It is. On the other hand, the linear expansion coefficient of PBT or a polymer compound containing PBT is 7 to 8 × 10. ^-Five ℃ ^-1 It is. When PBT or PBT-containing polymer compound contains high-strength fibers or inorganic fillers in an amount of 30 to 50%, the linear expansion coefficient is 2 to 3 × 10. ^-Five ℃ ^-1 And almost matches aluminum. At this time, the molding shrinkage also decreases. In more detail about the molding shrinkage rate, the high crystallinity of PBT increases the shrinkage rate. Therefore, it is possible to further lower the compound by mixing PET, PC, ABS, PS, etc., which are low crystallinity resins. . However, since the PBT concentration also decreases, specifically, trial and error are necessary.
[0034]
[injection molding]
After being immersed in a water-soluble amine compound (or ammonia) aqueous solution, the dried metal frame is inserted into an injection mold, and the space surrounded by the bottom, sides, and bent protrusions ( In addition, the thermoplastic resin composition is injected into a cavity portion formed in a desired space for forming a spacer or the like described later, and the thermoplastic resin composition is adhered to the surface of the metal frame in the space, thereby And resin are firmly integrated.
[0035]
The injection conditions will be described. The higher the mold temperature and the injection temperature, the better results can be obtained, but it will not be increased excessively, and a sufficient adhesive effect can be exhibited under substantially the same conditions as in normal injection molding using the thermoplastic resin composition. In order to increase the adhesive strength, it is better to keep in mind that pin gates are used as much as possible in the mold gate structure. In the pin gate, the resin temperature instantaneously rises due to shear friction generated when passing through the resin, which seems to produce a good effect. In short, it is presumed 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.
[0036]
[Action]
According to the present invention, the thermoplastic resin composition is attached to the surface of the metal frame in the space surrounded by the bottom portion, the side portion, and the protrusion by an insert molding technique, so that the thermoplastic resin composition is a metal. Since it adheres to the three surfaces of the frame (that is, the bottom surface, the side surface, and the protrusion surface), the metal frame and the thermoplastic resin composition can be firmly integrated. The reason why this is possible is that the metal frame was treated with an aqueous solution of a water-soluble amine compound (or ammonia). It is presumed that a metal surface state having moderate etching and moderate reactivity was obtained by this treatment. By using the present invention, various control equipment for industrial use, household appliances, communication equipment such as mobile phones, medical equipment, housings used for mounting on vehicles and building materials, structural parts, exteriors, etc. In the production of parts and the like, both the goodness of the metal frame and the good thermoplastic resin composition can be achieved, the productivity and the mass productivity can be improved, and the shape and structure can be designed freely.
[0037]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following, an example in which the composite of metal and resin according to the present invention is applied to a housing of a so-called notebook personal computer (hereinafter referred to as “personal computer”) will be described. First, FIG. 1 is an exploded perspective view showing a personal computer 1 including a lower housing 4 that is a composite of metal and resin according to the present invention. The personal computer 1 has a keyboard 2a and a display 2b, and is an upper housing 2 that forms an outer shell of the personal computer 1, and a metal-resin composite according to the present invention, and a lower portion that also forms the outer shell of the personal computer 1. An electric circuit board 3 having a housing 4 and an electronic device 3a (for example, CPU, ROM, RAM, disk drive device, etc.) that generates electromagnetic waves and interposed between the upper housing 2 and the lower housing 4; It consists of.
[0038]
Next, FIG. 2 is a perspective view showing details of the lower housing 4. The lower housing 4 includes a side portion 7 standing from the bottom portion 6, and a protruding portion 8 that protrudes from the side portion 7 and can be bent with respect to the side portion 7. And a metal frame having a bent shape and structure, and the thermoplastic resin composition attached to the surface of the metal frame.
[0039]
Here, the metal frame 5 is formed by bending a metal plate 5 in which the side portion 7 and the protruding portion 8 are notched to form a rectangular bottom portion 6 and four pieces standing at right angles from the four circumferences of the bottom portion 6. The side portions 7, 7, 7, and 7 and four protrusions 8, 8, 8, and 8 that are bent in parallel with the bottom portion 6 so as to cover the four corner portions intersecting each other are formed. Open container.
[0040]
The thermoplastic resin composition is attached to the surface of the metal frame in the space surrounded by the bottom portion 6, the side portion 7, and the bent projection portion 8 to form the boss portion 9. The boss 9 is provided with a hole into which a pin 2c (see FIG. 1) protruding downward from the four corners of the upper housing 2 is inserted. Further, the thermoplastic resin composition is attached to the center of the metal frame at the center of the bottom to form the spacer 10. The electric circuit board 3 is placed on the spacer 10 when the personal computer 1 is assembled.
[0041]
The lower housing 4 described above is manufactured after the metal frame is manufactured by the manufacturing process shown in FIG. 3, the metal frame is immersed in a water-soluble amine compound (or ammonia) aqueous solution, and then dried. It is manufactured by inserting the metal frame into an injection mold shown in FIG. 4 and injecting the thermoplastic resin composition.
[0042]
Specifically, as shown in FIG. 3 (a), first, four sides 7, 7, 7, and 7 are formed by cutting a rectangular metal plate and performing notching. Protruding portions 8, 8, 8, and 8 protruding from one end of the portion are formed. In the side portion 7, a cut portion 7a is formed as necessary. The cut portion 7a is a portion for forming an opening communicating with the disk drive device and various connection ports.
[0043]
Next, as shown in FIG. 3 (b), bending is performed by bending the four side portions 7, 7, 7, 7 vertically with respect to the bottom portion 6, and the respective side portions are fixed to each other by welding or an adhesive. To do. Further, as shown in FIG. 3 (c), the four protrusions 8, 8, 8, 8 are parallel to the bottom 6 with respect to each side so as to cover the four corners intersecting each other. A boss hole 8a into which the pin 2c is inserted is formed in each projection portion. If necessary, the cutting and polishing steps, the chemical etching step, and the cleaning step are performed on the manufactured metal frame.
[0044]
And the process which immerses the surface of a metal frame in the water-soluble amine compound (or ammonia) aqueous solution is performed. For example, when hydrazine is used as a water-soluble amine compound, a commercially available hydrazine aqueous solution having a concentration of 60% is diluted with ion-exchanged water to prepare a hydrazine aqueous solution having a concentration of 3% as hydrazine, and the pretreatment is performed. Then, a metal frame that has been washed with water and dried is added, and the liquid is stirred and taken out after about 2 minutes of immersion, and washed with ion-exchanged water separately prepared.
[0045]
Next, as shown in FIG. 4, a metal frame that has been subjected to hydrazine treatment is inserted into an injection mold 11 and the thermoplastic resin composition is injected. Specifically, a metal frame is inserted into a cavity formed in the movable mold 12 that constitutes the injection mold 11, the fixed mold 12 that also constitutes the injection mold 11 is closed, and the slide core 14. Is moved downward to insert the pin 14a protruding from the slide core 14 into the boss hole 8a. The runner 15 and the gate 16 are inserted into the space S1 surrounded by the bottom 6, the side 7, the protrusion 8, and the movable mold 12 and the space S2 surrounded by the bottom 6 and the movable mold 12. Then, the molten thermoplastic resin composition is injected to adhere the metal frame and the thermoplastic resin composition to form the lower housing 4.
[0046]
In the lower casing 4 manufactured in this way, the thermoplastic resin composition is adhered to the surface of the metal frame in the space S1, so that the thermoplastic resin composition is attached to the three surfaces of the metal frame (that is, the surface of the bottom 6). And the surface of the side portion 7 and the surface of the protruding portion 8), the metal frame and the thermoplastic resin composition can be firmly integrated. Further, the shape and structure can be freely designed so that the spacer 10 is formed in the space S2.
[0047]
【Example】
Examples of the present invention will be described in detail below instead of experimental examples.
[0048]
[Experimental Example 1]
A metal frame was manufactured by the manufacturing process shown in FIG. 3 using a commercially available 1 mm thick aluminum plate (which is considered to be A1050 aluminum) for electric work obtained by a rolling method. The metal frame was immersed in acetone for 10 minutes and taken out, and washed with tap water. Subsequently, a 3% sodium hydroxide aqueous solution was prepared in a SUS vat, and the metal frame was immersed for 1 minute for chemical etching, taken out, and washed with tap water. Next, 1% dilute nitric acid was prepared in another SUS vat, and the metal frame was immersed for 1 minute for neutralization. The sample was taken out and thoroughly washed with tap water, and further washed with ion exchange water.
[0049]
On the other hand, a commercially available hydrazine aqueous solution having a concentration of 60% was diluted with ion-exchanged water to prepare a hydrazine aqueous solution having a concentration of 3% as hydrazine. The above-described metal frame from which water had been drained was added, and the liquid was occasionally stirred with a glass rod. A small foaming occurred from the surface of the metal frame, and the point at which the surface started to become slightly black was determined as the end point and was pulled up from the hydrazine aqueous solution. This period was about 2 minutes of immersion, and it was taken out and put into a SUS bat containing ion exchange water prepared separately.
[0050]
After stirring well, it was poured into a plastic colander to drain the water, and further ion exchange water was applied to wash the metal frame. Thereafter, it was forcibly dried using an air gun, and stored in a polyethylene bag with a chuck that can seal the opening. Then, 3 days after the start of storage, the metal frame was opened from the plastic bag and taken out from the plastic bag. The metal frame was picked up with gloves so that oil and the like did not adhere, and inserted into the injection mold 11. The mold temperature was 90 ° C., the final part temperature of the heating cylinder of the injection molding machine and the nozzle temperature were 260 ° C. PBT / PET resin containing 20% glass fiber and 20% fine clay filler (PBT about 80% + PET about 20 %, A particularly compounded compound from “Tough Pet Series” manufactured by Mitsubishi Rayon Co., Ltd.) was injected to obtain the lower housing 4 shown in FIG.
[0051]
The lower casing 4 was left in the room for 2 days after molding, and then the adhesion was inspected. The metal plate 5 was pressed on the desk and pressed by strongly pressing the boss 9 and the spacer 10 with a finger, but could not be peeled off even when pressed until the finger was likely to be scratched.
[0052]
In addition, the temperature cycle test was implemented about the lower housing | casing 4 manufactured separately. Specifically, the temperature is raised from room temperature at + 0.7 ° C./min to 85 ° C. for 2 hours, then cooled to −40 ° C. at a rate of −0.7 ° C./min, and then held at −40 ° C. for 2 hours. This time, the temperature was raised at + 0.7 ° C./min, returned to 85 ° C., left for 2 hours, and then cooled to −40 ° C. again. After 100 cycles of this temperature cycle test, the same adhesive strength was tested as above, but the result was the same as when the temperature cycle test was not performed.
[0053]
Further, a high temperature and high humidity test was conducted on the separately manufactured lower housing 4. This high-temperature and high-humidity test is to stand for 24 hours under conditions of 85 ° C. and 60% humidity, and return to room temperature over 1 hour. After this high-temperature and high-humidity test, the same adhesive strength was tested as described above, but the results were the same as when the high-temperature and high-humidity test was not performed.
[0054]
[Experiment 2]
A metal frame treated with hydrazine was prepared and stored in the same manner as in Experimental Example 1. However, after this treatment, those stored for 1 week were used. Except for this, the lower housing 4 shown in FIG. 2 was obtained in the same manner as in Experimental Example 1. The obtained lower casing 4 was examined for adhesive strength in the same manner as in Experimental Example 1. The result was the same as in Experimental Example 1, and the adhesion was very strong. When the lower casing 4 subjected to the temperature cycle test was tested for adhesive strength in the same manner as in Experimental Example 1, the result was the same as in Experimental Example 1 and the adhesion was very strong.
[0055]
[Experiment 3]
The thermoplastic resin composition to be injected was made into PBT containing no filler (“Tuffpet G1030B” manufactured by Mitsubishi Rayon Co., Ltd.). Except for this, the lower housing 4 shown in FIG. 2 was obtained in exactly the same manner as in Experimental Example 1. The obtained lower casing 4 was examined for adhesive strength in the same manner as in Experimental Example 1. The result was the same as in Experimental Example 1, and the adhesion was very strong. In the case of the lower case 4 in which the temperature cycle test was performed only twice, when the adhesive strength was inspected in the same manner as in Experimental Example 1, the boss portion 9 and the spacer 10 could be peeled off with a finger. It was. The absence of filler appeared to weaken the temperature cycle test.
[0056]
[Experimental Example 4]
A commercially available 28% ammonia water was used instead of the hydrazine aqueous solution and the immersion time was 20 minutes. The metal frame was treated in the same manner as in Experimental Example 1, and the PBT resin composition was injection molded. The lower housing | casing 4 shown in 2 was obtained. The obtained lower housing 4 was left in the chamber after molding for 2 days, and then the adhesion was examined in the same manner as in Experimental Example 1. The result was the same as in Experimental Example 1, and the adhesion was very strong.
[0057]
[Experimental Example 5]
150 g of commercially available methylamine was dissolved in 1 liter of ion-exchanged water. Except that this aqueous solution was used in place of ammonia water, the metal frame was treated in the same manner as in Experimental Example 4, and the PBT resin composition was injection-molded to obtain the lower housing 4 shown in FIG. The obtained lower housing 4 was left in the chamber after molding for 2 days, and then the adhesion was examined in the same manner as in Experimental Example 1. The result was the same as in Experimental Example 1, and the adhesion was very strong.
[0058]
[Experimental Example 6]
A metal frame was manufactured by the manufacturing process shown in FIG. 3 using a commercially available 1 mm thick aluminum plate for electric work obtained by a rolling method. This metal frame was affixed to a rubber sheet with double-sided tape and placed in a blasting apparatus. The air pulse time was set so that the irregularities were at a level of about 5 μm, and air blasting was performed. After taking out from the blasting apparatus and leaving it within an average of 5 hours, it was taken out by being immersed in acetone for 10 minutes and washed with ion-exchanged water.
[0059]
Next, in the same manner as in Experimental Example 1, the metal frame was immersed in a 3% strength hydrazine aqueous solution for 2 minutes for treatment, taken out, and placed in a beaker containing ion exchange water prepared separately. After stirring well, it was poured into a plastic colander to drain the water, and further ion exchange water was applied to wash the metal frame. Thereafter, it was forcibly dried using an air gun and stored in a drier filled with a calcium chloride desiccant at the bottom.
[0060]
The metal frame was taken out of the dryer 3 days after the start of storage, and was picked with gloves so that oil and the like did not adhere, and inserted into the injection mold 11. The mold temperature was 100 ° C., the final partial temperature of the heating cylinder of the injection molding machine and the nozzle temperature were 270 ° C., and the same PBT / PET resin used in Example 1 was injected, and the lower housing shown in FIG. Body 4 was obtained.
[0061]
The lower housing 4 was left in the room for 1 week after being molded, and then the adhesion was inspected. The metal plate 5 was pressed on the desk and pressed by strongly pressing the boss 9 and the spacer 10 with a finger, but could not be peeled off even when pressed until the finger was likely to be scratched.
[0062]
In addition, the temperature shock test was implemented about the lower housing | casing 4 manufactured separately. In this test, the case was placed in a hot air dryer maintained at 85 ° C. for 2 hours, taken out at room temperature for 5 minutes, and then placed in a freezer maintained at −40 ° C. for 2 hours. Moreover, it is a repetitive test that is placed at room temperature for 5 minutes and put into an 85 ° C. hot air dryer. This temperature raising / lowering cycle was carried out 10 times, and the adhesion was examined. The result was the same as the case where the temperature shock test was not conducted.
[0063]
Further, a high temperature and high humidity test was conducted on the separately manufactured lower housing 4. This high-temperature and high-humidity test is to stand for 24 hours under conditions of 85 ° C. and 60% humidity, and return to room temperature over 1 hour. After this high-temperature and high-humidity test, the same adhesive strength was tested as described above, but the results were the same as when the high-temperature and high-humidity test was not performed. When viewed as a whole, surprisingly stable results were obtained as a destructive test of the adhesive.
[0064]
Finally, a modification of the present invention will be described.
[0065]
In the above embodiment, the example in which the composite of the metal and the resin according to the present invention is the lower housing 4 of the personal computer 1 is described. However, the present invention is not limited to this, and the composite is not limited to various industrial control devices, households. There are no particular limitations on the application, as long as it is an electrical appliance, a communication device such as a mobile phone, a medical device, a housing, a structural component, an exterior component, etc. used for mounting on vehicles or building materials.
[0066]
In the above embodiment, the metal frame constituting the composite of metal and resin (lower housing 4) is formed by bending the metal plate 5 in which the side 7 and the protrusion 8 are notched. However, the present invention is not limited to this, and the metal frame is formed by welding, for example, a metal plate that is integrally formed by pressing, or a metal plate that constitutes the bottom portion 6 and a metal plate that constitutes the side portion 7 and the protruding portion 8. It may be the one that was made. Further, the metal frame is not limited to a rectangular opening container, and is not limited to one in which the bottom portion 6 and the side portion 7 are orthogonal, and is not limited to one in which the side portions 7 are also orthogonal (for example, a curve). The shape is not particularly limited.
[0067]
In the above embodiment, the example in which the surface treatment is performed with the aqueous solution of the water-soluble amine compound (or ammonia) after the metal plate 5 is bent and the metal frame is formed is not limited thereto. The same processing may be performed at the stage of the metal plate 5 before the metal frame is formed, and then the metal plate 5 may be bent to form the metal frame. In other words, if the surface treatment with the aqueous solution of the water-soluble amine compound (or ammonia) is performed before the thermoplastic resin composition is injected and attached to the metal frame, a process that particularly eliminates the effect is not necessary. If not, the timing is not limited. The process of erasing is a processing process that may be covered with oily materials, as it is clear in the previous description, such as being immersed in a strong acidic aqueous solution or being exposed to high-temperature steam. Thus, there are a process step in which anodization occurs, a step in which corrosion and rust occur, and the like.
[0068]
In the above embodiment, the example in which the aqueous solution of the water-soluble amine compound (or ammonia) is performed on the entire surface of the metal frame by immersing the entire metal frame in the aqueous solution has been described. Alternatively, it may be performed on at least a part of the metal frame to which the thermoplastic resin composition adheres.
[0069]
In the above embodiment, in the metal frame, an example in which one protrusion 8 protruding from one side 7 with respect to one corner is bent and covered, is not limited thereto, As shown in FIG. 5 (a), the two protrusions 8 and 8 protruding from the side portions 7 and 7 may be bent and covered with respect to one corner.
[0070]
In the above embodiment, the example in which the protrusion 8 is formed at the corner in the metal frame has been described. (C) As shown in FIG. 5, the protrusion 8 may be formed in the middle of the side portion 7, and according to this, the metal frame and the thermoplastic resin composition can be firmly integrated in the middle of the side portion 7.
[0071]
Furthermore, FIG. b ), For example, by further bending the tip of the projection 8, the biting portion 8 that bites into the thermoplastic resin composition (boss portion 9) at the tip of the projection 8. a According to this, the metal frame and the thermoplastic resin composition can be more firmly integrated. Biting site 8 a As long as it bites into the thermoplastic resin composition, its shape is not particularly limited.
[0072]
【The invention's effect】
As described in detail above, according to the metal / resin composite and the method for producing the same according to the present invention, the metal frame and the thermoplastic resin composition are integrated easily without being peeled off. In addition, the goodness of the metal frame and the goodness of the thermoplastic resin composition are made compatible, the productivity is high and the mass productivity is high, the shape and structure can be freely designed, and the thermoplastic resin composition can be used on the three sides of the metal frame ( That is, the metal frame and the thermoplastic resin composition can be tightly integrated with each other because they adhere to the bottom surface, the side surface, and the projection surface. Therefore, it was possible to produce a casing of an electronic device that has no problem in terms of shape, structure, and mechanical strength.
INDUSTRIAL APPLICABILITY According to the present invention, it is useful for reducing the weight of a mobile electronic device or the like provided with a metal casing and simplifying the manufacturing process of a device that requires an electromagnetic wave shield.
[Brief description of the drawings]
FIG. 1 is an exploded perspective view showing a personal computer including a lower housing that is a composite of metal and resin according to the present invention.
FIG. 2 is a perspective view showing details of a lower housing.
FIG. 3 is a perspective view illustrating a manufacturing process of a metal frame.
FIG. 4 is a cross-sectional view of an injection mold.
FIG. 5 is a perspective view showing a modified example of the lower housing.
[Explanation of symbols]
1 ... PC
2… Upper housing
2a ... Keyboard
2b ... Display
2c ... pin
3 ... Electric circuit board
3a ... electronic equipment
4 ... Lower housing
5 ... Metal plate
6 ... Bottom
7 ... Side
7a ... notch
8 ... Protrusions
8a ... Boss hole
8b ... bite
9: Boss part (thermoplastic resin composition)
10. Spacer (thermoplastic resin composition)
11 ... Injection mold
12 ... Moveable side template
13 ... Fixed side template
14 ... Slide core
15 ... Lanna
16 ... Gate
S1 ... Space
S2 ... Space

Claims (12)

A metal that has a side that is erected from the bottom, a protrusion that protrudes from the side and can be bent with respect to the side, and whose surface is treated with an aqueous solution of a water-soluble amine compound. A metal frame,
A polyalkylene terephthalate, a copolymer mainly composed of the polyalkylene terephthalate, or the polyalkylene terephthalate, which is attached to the surface of the metal frame in a space surrounded by the bottom portion, the side portion, and the bent projection. One or more selected from thermoplastic resin compositions containing
A composite of metal and resin. The metal / resin composite according to claim 1,
The metal-resin composite, wherein the water-soluble amine compound is hydrazine or a lower amine compound. The metal / resin composite according to claim 1,
A metal-resin composite comprising ammonia instead of the water-soluble amine compound. In the metal-resin composite according to claim 1 selected from claims 1 to 3,
A metal / resin composite, wherein the metal frame is made of an aluminum alloy. The metal / resin composite according to claim 1 selected from claims 1 to 4.
A metal-resin composite, wherein the polyalkylene terephthalate is polybutylene terephthalate. The metal / resin composite according to claim 1 selected from claims 1 to 4.
The thermoplastic resin composition 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, or poly A metal / resin composite comprising at least one selected from a polymer compound of butylene terafufflate and polystyrene. In the composite of a metal and a resin according to claim 6,
The compound is added with high-strength fibers such as glass fibers, carbon fibers, and aramid fibers, and / or inorganic fillers for resin filling such as calcium carbonate, magnesium carbonate, silica, talc, and clay. A composite of metal and resin. The metal / resin composite according to claim 1 selected from claims 1 to 7,
The metal frame is subjected to a physical surface renewal operation by cutting or polishing before the surface is treated, and / or subjected to chemical etching performed by immersing in a chemical aqueous solution. A composite of metal and resin characterized by the above. 9. The metal / resin composite according to claim 1 selected from claim 1 to claim 8,
A metal-resin composite, wherein the metal frame is formed by bending a metal plate in which the side portions and the protrusions are notched. The metal / resin composite according to claim 1 selected from claims 1 to 9,
The metal-resin composite, wherein the protrusion is formed at a corner of the metal frame where the sides cross each other. In the metal-resin composite according to claim 1 selected from claims 1 to 10,
A metal / resin composite characterized in that a bite portion that bites into the thermoplastic resin composition is formed at the tip of the protrusion. A method for producing a composite of a metal and a resin according to claim 1,
After the treatment of immersing in the water-soluble amine compound aqueous solution is performed, the dried metal frame is inserted into an injection mold,
A method for producing a composite of a metal and a resin, comprising injecting the thermoplastic resin composition containing the polyalkylene terephthalate into a space surrounded by the bottom portion, the side portion, and the bent projection portion. .

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