JP6496990B2 - Housing and method for manufacturing the same - Google Patents

Description

  The present invention relates to a housing and a manufacturing method thereof.

  Electronic devices such as mobile phones, smartphones, PDAs (Personal Digital Assistants), notebook personal computers, and navigation devices are required to be thin and lightweight and robust. The casings of these electronic devices are often formed of ABS resin or polycarbonate.

  In recent years, with the further miniaturization and high performance of electronic devices, it has been studied to form a conductive pattern in a part of a housing to have a function as an antenna or a function as a wiring board.

JP 2003-304047 A JP 2005-149365 A

  The conductive pattern formed on the housing is required to have high adhesion to the housing and not easily peel off.

  It is an object of the disclosed technology to provide a housing having a conductive pattern with high adhesion and a method for manufacturing the same.

  According to another aspect of the disclosed technology, a step of attaching a conductive ink to a sheet to form a conductive pattern, a step of attaching an adhesive layer containing a triazine compound on the surface of the housing body, There is provided a method of manufacturing a housing having a step of transferring the conductive pattern to an adhesive layer.

  According to the casing and the manufacturing method according to the above aspect, the adhesion between the casing body and the conductor pattern is high.

Drawing 1 is a flowchart showing the manufacturing method of the frame concerning an embodiment. FIG. 2 is a schematic cross-sectional view (part 1) illustrating the method for manufacturing the housing according to the embodiment. FIG. 3 is a schematic cross-sectional view (part 2) illustrating the method for manufacturing the housing according to the embodiment. FIG. 4 is a schematic cross-sectional view (part 3) illustrating the method for manufacturing the housing according to the embodiment. FIG. 5 is a schematic cross-sectional view (No. 4) illustrating the method for manufacturing the housing according to the embodiment. FIG. 6 is a diagram illustrating an example in which a wireless LAN antenna is provided in a display-side casing of a notebook personal computer, and wiring is provided in a keyboard-side casing. FIG. 7 is a diagram illustrating an example in which a non-contact IC communication antenna, a wireless LAN antenna, and a call antenna are provided in a smartphone housing. FIG. 8 is a diagram showing the results of a three-point bending test performed on the sample pieces of Example 1, Comparative Example 1, and Comparative Example 2. FIG. 9 is a diagram showing the results of performing a tape peel test on the casings of Example 2, Comparative Example 3, and Comparative Example 4. FIG. 10 is a diagram showing the results of examining the amount of deformation and the presence or absence of peeling of the conductive pattern by applying a load to the central part of the casings of Example 3, Comparative Example 5 and Comparative Example 6. FIG. 11 is a diagram showing the results of examining the flame retardancy of the specimens of Example 4 and Comparative Example 7.

  Hereinafter, before describing the embodiment, a preliminary matter for facilitating understanding of the embodiment will be described.

  In order to form a conductive pattern on the housing for electronic equipment, it is conceivable to form a desired conductive pattern on the surface of the housing with, for example, conductive ink, and then baked and metallized the conductive ink.

  However, this method has the following problems. That is, generally, ABS resin or polycarbonate is used as a material for a housing for electronic equipment. While the heat resistance temperature of these resins is about 120 ° C. or lower, the firing temperature of the conductive ink is as high as about 150 ° C. to 200 ° C. For this reason, when the above method is actually implemented, the casing is deformed by heat when the conductive ink is baked.

  Therefore, the conductive ink is printed on the surface of the heat-resistant resin sheet to form a desired conductive pattern, and after the conductive ink is baked, the conductive pattern is transferred to a predetermined portion of the housing by a hot stamp method or the like. Can be considered.

  However, simply transferring the conductive pattern to the casing by the hot stamp method does not provide sufficient adhesion between the conductive pattern and the casing, and the conductive pattern easily peels from the casing.

  In the following embodiments, a case having a conductive pattern with high adhesion and a manufacturing method thereof will be described.

(Embodiment)
Drawing 1 is a flowchart showing the manufacturing method of the frame concerning an embodiment. 2 to 5 are schematic cross-sectional views showing the manufacturing method of the casing.

  First, in step S11, the casing body 11 having a desired shape is formed from ABS resin or polycarbonate. Thereafter, the process proceeds to step S12, and a thermoplastic resin kneaded with a triazine compound (for example, triazine thiol powder) is adhered to a predetermined region of the housing body 11 to form the adhesive layer 12 (see FIG. 2). Reference numeral 13 in FIG. 2 schematically shows a triazine compound contained in the adhesive layer 12.

  In this embodiment, a two-color molding machine is used, and first, polycarbonate is injected into the primary mold to form the housing body 11. Thereafter, the housing body 11 is moved into the secondary mold, and a thermoplastic resin in which a triazine compound is kneaded at a ratio of about 10 wt% is injected into the secondary mold to form the adhesive layer 12. However, the adhesive layer 12 may be attached to the surface of the housing body 11 by other methods.

  The thermoplastic resin used for the adhesive layer 12 is selected so that the melting point is lower than that of the resin of the housing body 11 and the appearance is not impaired during hot stamping. As the thermoplastic resin, for example, ABS resin, polycarbonate, polyamide and the like can be used.

  On the other hand, in step S13, conductive ink is printed on the heat resistant resin sheet 15 to form a desired conductive pattern 16 (see FIG. 3). Then, it transfers to step S14 and implements a heat treatment and metalizes conductive ink.

  The heat resistant resin sheet 15 is not particularly limited as long as it can withstand the temperature at which the conductive ink is baked, and a resin sheet such as polyimide, polyphenylene sulfide, polyamide, polyetherimide, or liquid crystal polymer can be used. Further, as the conductive ink, metal nanoparticle ink or conductive paste can be used.

  The conductive ink printing method may be selected according to the viscosity of the ink, and an inkjet method, a screen printing method, an offset printing method, or the like can be used. FIG. 3 schematically shows a state in which the conductive pattern 16 is formed by discharging the conductive ink 18 from the printer head 17 of the ink jet printer.

  Further, the firing temperature and firing time may be set according to the ink. For example, the firing temperature is about 150 ° C. to 200 ° C., and the firing time is about 1 hour.

  In addition, it is preferable that the resin sheet 15 is provided with a marker or the like that serves as a mark when aligning with the housing body 11. For example, the resin sheet 15 may be provided with a hole that fits into a protrusion provided in the housing body 11 to serve as a marker.

  Next, the process proceeds to step S15, and the conductive pattern 16 on the resin sheet 15 is transferred to the housing body 11 side through the adhesive layer 12 by a hot stamp method (see FIG. 4). Specifically, the resin sheet 15 on which the conductive pattern 16 is formed is mounted on the surface of the heating block 21. Thereafter, the heating block 21 is heated to a temperature at which the ABS resin is softened (for example, 90 ° C.) by an electric heater (not shown), and a load of, for example, 3 kgf is applied to transfer the conductive pattern 16 to the housing body 11. .

  The triazine compound in the adhesive layer 12 is bonded to both the resin in the adhesive layer 12 and the conductive pattern 16 by the heat and pressure at this time, and the adhesive layer 12 and the conductive pattern 16 are firmly bonded. In this embodiment, since the conductive pattern 16 is hot stamped in a state where the adhesive layer 12 (ABS resin) is sufficiently softened, the conductive pattern 16 is immersed in the adhesive layer 12, and the surface of the adhesive layer 12 and the surface of the conductive pattern 16 are Are arranged on the same plane.

  Next, the heating block 21 is removed, and when the adhesive layer 12 and the conductive pattern 16 are cooled to a certain temperature, the resin sheet 15 is peeled off (see FIG. 5).

  In this way, the housing 10 provided with the conductive pattern 16 is completed. In addition, the code | symbol 13a in FIG. 5 has shown typically the triazine compound couple | bonded with both the housing | casing main-body part 11 (resin) and the conductive pattern 16. FIG.

  FIG. 6 shows an example in which a wireless LAN antenna 32 is provided on a display-side casing 31 of a notebook personal computer, and wiring 35 connected to a liquid crystal panel 34 is provided on a keyboard-side casing 33. Here, reference numerals 31a and 33a are housing main body portions made of ABS resin or polycarbonate. Each of the antenna 32 and the wiring 35 includes the conductive pattern 16 formed through the steps shown in FIGS.

  FIG. 7 shows an example in which a housing 36 for a smartphone is provided with a communication antenna 37 for a non-contact type IC (for example, FeliCa (registered trademark)), a wireless LAN antenna 38, and a communication antenna 39. Yes. Here, the code | symbol 36a is a housing main-body part which consists of ABS resin or a polycarbonate. Further, each of the antennas 37, 38, and 39 includes the conductive pattern 16 formed through the steps shown in FIGS.

  Hereinafter, effects of the embodiment will be described.

  Conventionally, it is known that when a triazine compound is applied to the surface of a metal plate, the triazine compound is bonded to both the resin and the metal, and the metal and the resin can be firmly bonded. Therefore, for example, it is conceivable to apply a triazine compound to the surface of the conductive pattern formed on the resin sheet, and then transfer the conductive pattern to the housing body by a hot stamp method.

  However, since the triazine compound has high reactivity, the adhesive force is drastically reduced between the application to the surface of the conductive pattern and the hot stamping. For this reason, it is conceivable that the above-described method has poor workability, and that the adhesiveness between the casing body and the conductive pattern is insufficient and the quality is not stable.

  On the other hand, in this embodiment, the adhesive layer is formed of a thermoplastic resin kneaded with a triazine compound. In this case, since the resin covers the triazine compound, the reaction of the triazine compound is suppressed. Then, the triazine compound and the conductive pattern come into contact with each other due to the temperature and pressure at the time of hot stamping, and the adhesive force of the triazine compound is developed, so that the housing body and the conductive pattern are firmly bonded. This improves productivity and stabilizes product quality.

(Experiment 1)
Hereinafter, the result of having transferred the conductive pattern to the surface of the casing main body by the above-described method and examining the joint strength by the three-point bending test will be described.

  First, the housing of Example 1 was produced. A method for manufacturing the housing of Example 1 is described below.

  Polycarbonate (Iupilon (registered trademark) manufactured by Mitsubishi Engineering Plastics Co., Ltd.) was used as the resin for the housing body. The resin used as the adhesive layer was obtained by melt-mixing a triazine compound (Dysnet (registered trademark) F manufactured by Sankyo Kasei Co., Ltd.) at a ratio of 10 wt% with ABS resin (Stylac (registered trademark) manufactured by Asahi Kasei Chemicals Corporation). I used something. The ABS resin and the triazine compound were kneaded with a biaxial kneader, and then several mm size pellets were prepared with a water-cooled pelletizer.

  Next, using a two-color molding machine, the casing body was formed of polycarbonate, and the adhesive layer was formed of ABS resin kneaded with the triazine compound (see FIG. 2).

  That is, polycarbonate was injected into the primary mold under the conditions of a cylinder temperature of 280 ° C., a mold temperature of 110 ° C., and a gauge pressure of 200 MPa to form a housing body. Thereafter, the casing main body is moved into the secondary mold, and the ABS resin in which the triazine compound is kneaded in the secondary mold is subjected to conditions of a cylinder temperature of 230 ° C., a mold temperature of 80 ° C., and a gauge pressure of 150 MPa. The adhesive layer was formed by injection.

  In this way, a case main body for a smartphone having the shape illustrated in FIG. 7 was obtained. In addition, here, for convenience of explanation, the case body portion including the adhesive layer is called. The size of the housing main body is 60 mm in width, 130 mm in length, and 10 mm in height. The casing body has a thickness of about 0.8 mm (the polycarbonate layer has a thickness of about 0.5 mm and the adhesive layer has a thickness of about 0.3 mm).

  On the other hand, as a heat resistant resin sheet, a liquid crystal polymer film having a thickness of 0.1 mm (Bexstar manufactured by Kuraray Co., Ltd.) was prepared. A silver paste was screen-printed on the resin sheet to form a conductive pattern having a width of 1 mm and a thickness of 10 μm. Thereafter, the conductive pattern was metallized by baking at a temperature of about 180 ° C. for 1 hour (see FIG. 3).

  Next, a resin sheet on which a conductive pattern was formed was mounted on the surface of the heating block formed by machining stainless steel (see FIG. 4). Then, while heating the heating block to a temperature of 90 ° C. at which the ABS resin was softened by an electric heater, a load of about 3 kgf was applied to transfer the conductive pattern to the casing body (adhesive layer). Then, after removing the heating block and cooling the housing body to room temperature, the resin sheet was peeled from the housing body (see FIG. 5).

  In this way, the housing of Example 1 was obtained.

  On the other hand, the casing of Comparative Example 1 was produced by the same method as in Example 1. However, in the casing of Comparative Example 1, the adhesive layer is formed of ABS resin that does not contain a triazine compound. Further, a casing main body was formed of polycarbonate, and a conductive pattern was transferred to the casing main body in the same manner as in Example 1 to produce a casing of Comparative Example 2. The housing of Comparative Example 2 is not provided with an adhesive layer.

  Test pieces each having a width of 10 mm, a length of 50 mm, and a thickness of 0.8 mm were cut out from the casings of Example 1, Comparative Example 1, and Comparative Example 2 thus produced.

  And the three-point bending test was implemented with respect to those sample pieces using a universal testing machine, and the presence or absence of peeling of a conductive pattern was investigated. In the three-point bending test, deformation was applied until the deflection amount was 10 mm. The result is shown in FIG. The three-point bending test was performed according to the method defined in JIS K7171.

  As shown in FIG. 8, in the test pieces of Comparative Examples 1 and 2, peeling occurred in the three-point bending test, whereas in the test piece of Example 1, the conductive pattern did not peel off.

In addition, when the specific resistance of the conductive pattern of each test piece of Example 1, Comparative Example 1, and Comparative Example 2 was measured, all were as low as about 10 ⁻⁸ Ω · m, and the conductive pattern formed by the above method was an antenna. Or it was confirmed that it could be used sufficiently as wiring.

(Experiment 2)
Hereinafter, the result of examining the bonding strength of the conductive pattern by the tape peel test for the housing produced by the method of the embodiment will be described.

  First, the housing of Example 2 was produced. The casing of Example 2 was manufactured by the same method as that of the casing of Example 1 described above. However, the conductive pattern was a square with a side of 50 mm, and was formed by printing a silver paste on a heat resistant resin sheet.

  Further, as Comparative Example 3, a housing similar to that of Example 2 was prepared except that the adhesive layer did not contain a triazine compound. Furthermore, as Comparative Example 4, a case similar to Example 2 was produced except that the adhesive layer was not provided.

  A tape peel test was performed on the casings of Example 2, Comparative Example 3, and Comparative Example 4 to examine the bonding strength of the conductor pattern. The result is shown in FIG. The tape peel test was performed according to the method defined in JIS Z0237.

  As can be seen from FIG. 9, in Comparative Example 3 in which the adhesive layer did not contain a triazine compound, the tape peel strength was 2.3 N / cm, and in Comparative Example 4 without the adhesive layer, the tape peel strength was 0.8 N / cm. . On the other hand, it was confirmed that in the case of Example 2 in which the adhesive layer contained a triazine compound, the tape peel strength was as high as 3 N / cm or more.

  From the experiments 1 and 2 described above, it was confirmed that the case produced according to this embodiment has a sufficiently high bonding strength between the case body and the conductive pattern.

(Modification)
In the above-described embodiment, the adhesive layer is formed of a resin containing a triazine compound. However, if the adhesive layer further contains a fiber reinforcing material such as carbon fiber or glass fiber, the strength of the housing can be improved. . Moreover, the flame retardance of a housing | casing can be improved by adding a flame retardant to an adhesion layer.

(Experiment 3)
A housing of Example 3 having the shape shown in FIG. 7 was created by the same method as in Example 1 described above. However, in the case of Example 3, the ABS resin serving as the adhesive layer was mixed at a ratio of 10 wt% of the triazine compound and 20 wt% of the glass fiber.

  On the other hand, as Comparative Example 5, a housing similar to that of Example 3 was prepared except that the adhesive layer did not contain a triazine compound. Further, as Comparative Example 6, a case similar to Example 3 was produced except that the adhesive layer was not provided.

  A stainless steel rod having a diameter of 10 mm is arranged in the central part of the housings of Example 3, Comparative Example 5 and Comparative Example 6, and a load of 5 kgf is applied to each housing through the rods. The amount and the presence or absence of peeling of the conductive pattern were examined. The result is shown in FIG.

  From FIG. 10, it can be seen that in Comparative Example 5 having an adhesive layer containing glass fibers and no triazine compound, the amount of deformation is small with respect to the load and the strength is high. However, in Comparative Example 5, peeling of the conductive pattern occurred when a load of 5 kgf was applied.

  Moreover, in the comparative example 6 which does not have an contact bonding layer, it turns out that there are many deformation amounts with respect to a load, and intensity | strength is not enough. And also in the comparative example 6, peeling of the conductive pattern occurred by applying a load of 5 kgf.

  On the other hand, in Example 3 having an adhesive layer containing glass fiber and a triazine compound, the amount of deformation is small and the strength is high even when a load of 5 kgf is applied. Further, even when a load of 5 kgf was applied, no peeling of the conductive pattern occurred.

(Experiment 4)
An adhesive layer was formed by adhering an ABS resin mixed with 10 wt% of a triazine compound and 10 wt% of a phosphorus-based flame retardant on a plate-like polycarbonate to obtain a test body of Example 4. A polycarbonate plate was used as a test sample of Comparative Example 7.

  And the flame retardance (flame resistance) of the test body of these Example 4 and the comparative example 7 was investigated. For flame retardancy, a gas burner flame having a diameter of 10 mm and a length of 20 mm was contacted at the center of a 100 mm square plate-shaped molded article, and the combustion state was examined. The result is shown in FIG.

  As can be seen from FIG. 11, in the test body of Example 4 having an adhesive layer containing a flame retardant, only the flame contact portion burned, whereas in the test body of Comparative Example 7, it burned to the outer edge.

  From Experiments 3 and 4 described above, it was confirmed that the strength and flame retardancy of the housing can be improved by adding a fiber reinforcement or a flame retardant to the adhesive layer.

  The following additional notes are disclosed with respect to the above embodiments.

(Supplementary note 1) a housing body,
An adhesive layer comprising a triazine compound;
And a conductive pattern formed on the casing body through the adhesive layer.

  (Supplementary note 2) The casing according to supplementary note 1, wherein the adhesive layer is mainly composed of a resin having a melting point lower than that of the material of the casing main body.

  (Additional remark 3) The housing | casing of Additional remark 1 or 2 characterized by the surface of the said contact bonding layer, and the surface of the said conductive pattern being located on the same plane.

  (Supplementary Note 4) The casing according to any one of Supplementary Notes 1 to 3, wherein the casing main body includes one of ABS resin and polycarbonate as a main component.

  (Additional remark 5) The housing | casing of any one of additional remark 1 thru | or 4 characterized by including a fiber reinforcement or a flame retardant in the said contact bonding layer.

(Appendix 6) A step of forming a conductive pattern by attaching a conductive ink to a sheet;
Attaching an adhesive layer containing a triazine compound on the surface of the housing main body;
And a step of transferring the conductive pattern to the adhesive layer.

  (Supplementary note 7) The method for manufacturing a casing according to supplementary note 6, wherein the transfer of the conductive pattern to the adhesive layer is performed by hot stamping.

  (Appendix 8) The casing according to appendix 6 or 7, wherein the sheet is a resin sheet of any one of polyimide, polyphenylene sulfide, polyamide, polyetherimide, and liquid crystal polymer. Production method.

  (Additional remark 9) The process of forming the said conductive pattern includes the process of printing the said conductive ink on the said sheet | seat, and the process of baking the said conductive ink, Any one of Additional remark 6 thru | or 8 characterized by the above-mentioned. The manufacturing method of the housing | casing as described in an item.

  DESCRIPTION OF SYMBOLS 10, 31, 33, 36 ... Housing | casing, 11 ... Housing | casing main-body part, 12 ... Adhesive layer, 15 ... Resin sheet, 16 ... Conductive pattern, 17 ... Printer head, 18 ... Conductive ink, 21 ... Heating block, 32 , 37, 38, 39 ... antenna, 34 ... liquid crystal panel, 35 ... wiring.

Claims (3)

  Forming a conductive pattern by attaching conductive ink to the sheet;
  Attaching an adhesive layer containing a triazine compound on the surface of the housing main body;
  Transferring the conductive pattern to the adhesive layer;
  A method for manufacturing a casing, comprising:   The method for manufacturing a housing according to claim 1, wherein the transfer of the conductive pattern to the adhesive layer is performed by hot stamping.   The process for forming the conductive pattern includes a step of printing the conductive ink on the sheet and a step of baking the conductive ink. Method.

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