JP2004281233A - Sheet for key switch and method of manufacturing key switch - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a sheet for a key switch capable of forming metallic luster of optional color only in an optional region and to provide a method of manufacturing the key switch. <P>SOLUTION: The sheet for the key switch formed by laminating a whole or partial metallic thin film layer and a partial transparent colored layer on a substrate sheet so as to have an overlapped part in at least one part is set in a molding die, molten resin is injected into the die, and the sheet for the key switch and the molten resin is integrated. Thereby, metallic luster of the optional color is easily formed only in the optional region. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a key switch sheet having a metallic luster of any color and a method of manufacturing a key switch, and can be applied to mobile phones, home appliances, automobile parts, communication devices, and the like.
[0002]
[Prior art]
2. Description of the Related Art Conventionally, among key switches used in mobile phones and the like, there is a key switch in which the surface of the key switch has a metallic luster in order to have a high-grade appearance. In order to obtain such a key switch, there is a method of forming a metal plating layer such as chrome plating on the surface of a key switch member made of a resin molded product. Also, in order to make characters and symbols shine at the time of so-called backlight irradiating with a light source from the back, the metal plating layer is removed by a method such as laser etching on the pattern of characters and symbols, or the metal plating layer is partially (For example, see Patent Document 1).
[0003]
[Patent Document 1]
Japanese Patent Application Laid-Open No. H11-167838
[Problems to be solved by the invention]
In the above key switch manufacturing method, the color of the metallic luster is derived from the color of the metal to be plated. It is necessary to form a coating layer. For example, when a metal plating layer is formed by chromium plating and then a yellow translucent coating layer is formed, a golden metallic luster can be obtained.
[0005]
However, in the above-described method, since the light-transmitting coating layer is formed entirely on the surface of the key switch, the pattern portions of characters and symbols are also covered by the light-transmitting coating layer, and the entire surface of the key switch is covered. There is a problem that the color of the light-transmitting coating layer is tinged.
[0006]
Accordingly, an object of the present invention is to provide a key switch sheet and a method for manufacturing a key switch, which can solve the above-described problems and can provide a metal luster of an arbitrary color only in an arbitrary region. And
[0007]
[Means for Solving the Problems]
The key switch sheet and the key switch manufacturing method of the present invention are configured as follows to achieve the above object.
[0008]
That is, the key switch sheet of the present invention is configured such that the base sheet has an area in which the entire or partial metal thin film layer and the partial transparent coloring layer at least partially overlap.
[0009]
In the above invention, the transparent coloring layer may be formed using a dye coloring ink, and the dye contained in the dye coloring ink may sublimate the surface of the base sheet.
[0010]
Further, in the above invention, the transparent colored layer may be formed using an ultraviolet curable ink.
[0011]
In the above invention, the transparent colored layer may be formed using a thermoplastic resin ink or a thermosetting resin ink.
[0012]
Further, the method for manufacturing a key switch according to the present invention is directed to a key switch sheet in which a metal thin film layer is partially or entirely laminated on a base sheet so as to have a region where at least a part thereof partially overlaps with a transparent coloring layer. Was set in a molding die, the molten resin was injected into the die, and the key switch sheet and the molten resin were integrated.
[0013]
Further, in the above invention, a key switch sheet preformed so as to have a three-dimensional shape of a desired key switch may be provided in a molding die.
[0014]
In the above invention, the overcoat layer may be laminated after the key switch sheet and the molten resin are integrated.
[0015]
BEST MODE FOR CARRYING OUT THE INVENTION
Embodiments of the present invention will be described in detail with reference to the drawings.
[0016]
FIG. 1 is a sectional view showing an embodiment of a key switch sheet according to the present invention. 2 to 5 are cross-sectional views showing one process of a method for manufacturing a key switch according to the present invention. 6 to 11 are sectional views showing one embodiment of the key switch sheet of the present invention. In the figure, 1 is a key switch, 2 is a key switch sheet, 3 is a base sheet, 4 is a metal thin film layer, 5 is a transparent coloring layer, 6 is an anchor layer, 7 is an adhesive layer, 10 is a molding resin, and 11 is a molding. The mold 12 is a gate.
[0017]
The key switch sheet 2 of the present invention is formed by laminating a metal thin film layer 4 partially or entirely and a partially transparent colored layer 5 on a base sheet 3 so as to have an area at least partially overlapping. (See FIGS. 1, 6-11).
[0018]
As a specific layer configuration of the key switch sheet 2, at least a metal thin film layer 4 and a transparent coloring layer 5 are laminated on the upper surface of the base sheet 3 (see FIGS. 6 and 7). One in which the transparent coloring layer 5 is at least laminated and the metal thin film layer 4 is at least laminated on the lower surface (see FIGS. 8 to 9), and one in which the transparent coloring layer 5 and the metal thin film layer 4 are at least laminated on the lower surface of the base sheet 3 (See FIGS. 10 to 11) and the like.
[0019]
As the base sheet 3, a single-layer film such as a polycarbonate resin, a polycarbonate-polybutylene terephthalate alloy resin, an acrylic resin, a urethane resin, or a laminated film made of two or more resins may be used.
[0020]
The thickness of the base sheet 3 is preferably in the range of 50 to 250 μm. If the thickness is less than 50 μm, the film forming process is difficult, and handling in each process tends to be poor. In addition, it is difficult to follow the elongation at the time of preforming, and the risk of breakage at a thin portion is increased. If the thickness exceeds 250 μm, it takes a long time to heat the key switch sheet 2 to the optimal state for preforming, and the production efficiency is poor. Connect.
[0021]
Further, the surface of the base sheet 3 may have a fine uneven shape. In this case, the metallic luster is suppressed and the user feels calm.
[0022]
The metal thin film layer 4 is a layer for expressing metallic luster.
[0023]
The metal thin film layer 4 is made of a metal such as aluminum, nickel, gold, platinum, chromium, iron, copper, tin, indium, silver, titanium, lead, and zinc, or an alloy or compound thereof, depending on the metallic luster color to be expressed. Can be used. In particular, in consideration of the stretchability and durability of the metal thin film layer 4, it is preferable to use chromium, indium, tin, or an alloy or compound thereof. The metal thin film layer 4 may be formed by a transfer method, a vacuum evaporation method, a sputtering method, an ion plating method, a plating method, or the like.
[0024]
The metal thin film layer 4 is formed entirely or partially. As a method of partially forming the metal thin film layer 4, a mask layer is partially formed on the metal thin film layer 4 formed on the entire surface of the base sheet 3 by a screen printing method or the like, and then dipped in an acid or alkali aqueous solution. Then, there is an etching method for removing a metal layer other than the laminated portion.
[0025]
The metal thin film layer 4 is preferably formed with a light transmittance of 0 to 50%. If the light transmittance exceeds 50%, the thickness of the metal thin film layer 4 becomes too thin, and a sufficient metallic gloss may not be obtained. When the metal thin film layer 4 is required to have a light-shielding property, a light-shielding colored layer having a total light transmittance of 0 to 20% may be separately formed. When the entire metal thin film layer 4 is required to have translucency, a translucent colored layer having a total light transmittance of 20 to 99% may be separately formed.
[0026]
The transparent coloring layer 5 is for forming the metal thin film layer 4 to have an arbitrary metallic luster color by being formed so that at least a part of the region overlaps with the metal thin film layer 4. In a region where the metal thin film layer 4 and the transparent coloring layer 5 overlap, it is possible to obtain a color developed by the coloring by the transparent coloring layer 5 in addition to the metallic luster by the metal thin film layer 4. If there is a region where the metal thin film layer 4 and the transparent coloring layer 5 do not overlap with each other and only the metal thin film layer 4 exists, a metallic luster color by the metal thin film layer 4 can be obtained in that region. In addition, if there is a region where the metal thin film layer 4 and the transparent coloring layer 5 do not overlap with each other and only the transparent coloring layer 5 exists, transparent coloring by the transparent coloring layer 5 can be obtained in that region.
[0027]
The transparent coloring layer 5 may be formed using a dye coloring ink, and the surface of the base sheet 3 may be sublimated and colored with a dye contained in the dye coloring ink. As the dye-colored ink, an ink in which a dye is blended in a resin binder and a solvent as a coloring component is preferably used. The dye-colored ink may be subjected to a sublimation coloring on the surface of the base sheet 3 through a drying process at a drying temperature of 80 to 95 ° C. for 1 to 2 hours. The depth at which the base sheet 3 is sublimated and colored is preferably 0.001 to 0.01 μm from the surface of the base sheet 3. If the depth is less than 0.001 μm, the colored metallic luster decoration may be impaired when the transparent colored layer 5 is scraped off during use. When the depth exceeds 0.01 μm, the base sheet 3 is simultaneously eroded by the solvent component, so that the strength of the base sheet 3 is impaired, and fine cracks may occur in the preforming step, the forming step, or the state of the molded article. There is.
[0028]
Further, the transparent coloring layer 5 may be formed using an ultraviolet curable ink. As the UV-curable ink, it is preferable to use an acrylate-based resin such as urethane acrylate, epoxy acrylate, or polyester acrylate as a binder and toned with a pigment or dye. By using an ultraviolet curable ink, it is possible to obtain an excellent surface strength. Further, by making the thickness of the transparent coloring layer 5 as a thick film of about 10 μm, a deeper colored metal pattern can be obtained. Further, by forming the transparent colored layer 5 to be thick and partially formed, the transparent colored layer 5 is pressed by the injection molding pressure, and the transparent colored layer 5 is sunk from the surface of the key switch sheet 2 so as to be three-dimensional. A visual effect is also obtained.
[0029]
Further, the transparent coloring layer 5 may be formed using a thermoplastic resin ink or a thermosetting resin ink. As the thermoplastic resin ink, one using an acrylic resin or a polycarbonate resin as a binder may be used. As the thermosetting resin ink, one using a polyester resin or a urethane resin as a binder may be used. By using a thermoplastic resin ink or a thermosetting resin ink, a colored layer having excellent transparency can be obtained, so that excellent metallic gloss can be obtained.
[0030]
The transparent coloring layer 5 may be formed partially using a screen printing method, a gravure printing method, or the like. In particular, when the metal thin film layer 4 is partially formed, it is desirable to use a sheet-fed screen printing method or a sheet-fed gravure printing method in which a pulling force is not applied while heating in a printing process in order to increase register accuracy.
[0031]
When the rotogravure printing method or the rotoscreen printing method is used, in order to secure the dimensional accuracy of the base sheet 3, a polyethylene terephthalate sheet having excellent heat resistance may be laminated and printed.
[0032]
If necessary, a symbol layer may be formed to represent characters, symbols, other figures, and the like. For the design layer, urethane resin, polyester resin, acrylic resin, olefin resin, vinyl chloride vinyl acetate copolymer resin, polyurethane resin, etc. are used as binders, and pigments or dyes of appropriate colors are contained as colorants. It is good to select and use a thermosetting ink or a solvent volatile ink as appropriate. As a method of forming the pattern layer, a normal printing method such as an offset printing method, a gravure printing method, and a screen printing method may be used. The design layer may be formed partially according to a desired design.
[0033]
Further, the adhesive layer 7 may be formed as needed. The bonding layer 7 is a layer for bonding the above-mentioned layers on the molding resin 10. As the adhesive layer 7, a heat-sensitive or pressure-sensitive resin suitable for the material of the molding resin 10 is appropriately used. For example, when the material of the molding resin 10 is a polycarbonate-based resin, an acrylic resin, a polystyrene-based resin, a polyamide-based resin, or the like that has an affinity for these resins may be used. Examples of the method for forming the adhesive layer 7 include a coating method such as a gravure coating method, a roll coating method, and a comma coating method, and a printing method such as a gravure printing method and a screen printing method. Also, the adhesive layer 7 can be formed by laminating an adhesive sheet made of the above material by a laminating method or the like. Further, the adhesive layer 7 may be transparent or translucent.
[0034]
Further, an anchor layer 6 may be provided between the above-described layers as needed. The anchor layer 6 is a layer for increasing the adhesion between the layers, and is a two-component curable urethane resin, a thermosetting resin such as a melamine resin or an epoxy resin, or a thermoplastic resin such as a vinyl chloride copolymer resin. Alternatively, an ionizing radiation curable resin or the like can be used. In particular, an acrylic polyol-based resin having excellent transparency, heat resistance and flexibility is preferably used between the metal thin film layer 4 and the other layers. Examples of the method of forming the anchor layer 6 include a coating method such as a gravure coating method, a roll coating method, and a comma coating method, and a printing method such as a gravure printing method and a screen printing method.
[0035]
The total thickness of each layer laminated on the surface of the base sheet 3 is preferably 3 to 30 μm. If the total film thickness is less than 3 μm, there is a possibility that a sufficient light-shielding property cannot be secured at a portion that becomes a thin portion due to extension during preforming. If the total film thickness exceeds 30 μm, the film thickness may interfere at the time of preforming, and sufficient shape reproduction at the corner may not be possible. In addition, since the residual solvent in each layer is hardly volatilized, there is a possibility that the releasability at the time of preforming is inferior and that the ink flows at the time of resin backing.
[0036]
As described above, the key switch sheet 2 can be obtained (see FIG. 1). The key switch 1 can be obtained using the key switch sheet 2 having such a configuration.
[0037]
First, the key switch sheet 2 is preformed as required (see FIG. 2).
[0038]
As the pre-molding die, one that can be processed into a desired three-dimensional shape of the key switch 1 is used. Further, a fine uneven shape for performing a matting process or a hairline process may be entirely or partially formed on the surface of the preforming die.
[0039]
In order to perform the preforming, a vacuum forming method, a press forming method, a vacuum forming method, a high pressure forming method, a hydraulic forming method, a die press forming method, or the like may be used. The preforming conditions are as follows: after softening by heating so that the surface temperature of the key switch sheet 2 becomes 100 to 180 ° C., a load of about 8.0 to 20.0 MPa is applied under pressure and along the surface of the preforming die. Preferably, it is deformed.
[0040]
As described above, the key switch sheet 2 can be preformed (see FIG. 2).
[0041]
Next, the key switch sheet 2 is placed in the molding die 11, and the molten resin is injected into the die to integrate the key switch sheet 2 with the molten resin.
[0042]
First, the key switch sheet 2 is fed into the molding die 11 (see FIG. 3).
[0043]
The molding die 11 is a mold that can obtain the key switch 1 by sandwiching the key switch sheet 2 in the molding die 11 and injecting a molten resin. A mold that can form a cavity from one mold having a concave portion to be formed and the other mold having a convex portion forming the back side of the key switch 1 can be used. The cavity surface may have fine irregularities. Since the cavity surface has fine irregularities, it is possible to form fine irregularities on the surface of the key switch sheet 2.
[0044]
The key switch sheet 2 is placed between the molding dies 11 using a key switch sheet 2 feeder or the like, and fixed by means such as a clamp.
[0045]
After the molding die 11 is closed, the molten resin is injected and filled into the molding die 11 from the gate 12, and simultaneously with forming the molding resin 10, the key switch sheet 2 is adhered to the surface thereof (see FIG. 4). .
[0046]
As the molding resin 10, it is preferable to use a polycarbonate resin excellent in impact resistance, an acrylic resin excellent in transparency, or the like. In addition, a general resin that can be used as a molding resin of the key switch 1, such as an acrylonitrile butadiene styrene copolymer resin, can be used. In addition, depending on the use of the key switch 1, if necessary, the key switch 1 may be colored so as to have translucency.
[0047]
If the mold resin is opened after the molding resin 10 is solidified, the key switch 1 in which the key switch sheet 2 and the molding resin 10 are integrated can be obtained (see FIG. 5).
[0048]
Further, post-processing may be performed on the surface of the key switch 1 as necessary. For example, in order to increase the surface strength of the key switch 1, an overcoat layer made of an ionizing radiation curable resin or the like may be formed.
[0049]
In addition, a decorative layer may be formed to express characters, symbols, and the like. The decorative layer may be formed by means such as a screen printing method and a pad printing method (also referred to as a tampo printing method or an octopus printing method). As the binder of the printing ink, an ultraviolet curable resin is preferably used. The ultraviolet curable resin is excellent in abrasion resistance and scratch resistance, and is solvent-free, so that there is no possibility of causing the deterioration of the base sheet 3 due to the solvent component. Further, there is no drip of the ink when the solvent in the ink is dried, and the reproducibility of the decorative layer such as characters and symbols is excellent.
[0050]
【Example】
Example 1 A single-sided matte polycarbonate resin film (Lexan manufactured by Asahi Glass Co., Ltd.) having a thickness of 125 μm was used as a base sheet, and its glossy surface was coated with an acrylic polyol resin at a thickness of 2 μm by a gravure coating method to form an anchor layer. Then, aluminum is formed by a sputtering method in a light transmittance range of 20% ± 5% to form a metal thin film layer, and then translucent using a urethane two-component curable ink (SG410 manufactured by Seiko Advance Co., Ltd.). A colored layer was formed, and then an adhesive layer made of a vinyl chloride-vinyl oxide copolymer resin resin was formed. Further, on the mat surface of the base sheet, a transparent colored layer is partially formed by a silk screen method using a dye-colored ink, and then a pattern layer showing a pattern of a display character is formed using an impermeable urethane-based screen ink, A key switch sheet was obtained.
[0051]
The key switch sheet was preformed by a high-pressure molding method to obtain a keypad-shaped three-dimensional double-sided key switch sheet having a plurality of convex shapes.
[0052]
Next, this is placed in a molding die having a cavity shape corresponding to the three-dimensional shape, and a polycarbonate resin (Macrolon 2205 manufactured by Bayer Corporation) is melted, injected, and solidified by cooling, so that a three-dimensional shape key switch sheet is integrated with the surface. Key switch was obtained.
[0053]
The key switch thus obtained had a semi-gloss-tone colored metallic glossy pattern having a surface illumination function.
[0054]
Example 2 A single-sided matte polycarbonate resin film (Panlite manufactured by Teijin Chemicals Limited) having a thickness of 125 μm was used as a base sheet, and its glossy surface was coated with an acrylic polyol resin to a thickness of 2 μm by a gravure coating method to form an anchor layer. Is formed by sputtering, aluminum is formed in a light transmittance range of 20% ± 5% to form a metal thin film layer, and then transmitted using a urethane two-liquid curing ink (SG410, manufactured by Seiko Advance Co., Ltd.). A light colored layer was formed, and then an adhesive layer made of a vinyl chloride vinyl oxide copolymer resin was formed. In addition, a transparent coloring layer is partially formed on the mat surface of the base sheet by a screen printing method using an ultraviolet-curable ink (UIM manufactured by Jujo Chemical Co., Ltd.), and then the display characters are formed using an opaque ultraviolet-curable ink. A pattern layer showing a pattern was formed to obtain a key switch sheet.
[0055]
The sheet for a double-sided key switch was preformed by a high-pressure molding method to obtain a three-dimensional keypad-shaped sheet for a keypad having a plurality of convex shapes.
[0056]
Next, this is placed in a molding die having a cavity shape corresponding to a three-dimensional shape, and a polycarbonate resin (Macrolon 2205 manufactured by Bayer Corporation) is melted, injected, and cooled and solidified to integrate the key switch sheet with the surface. Got a key switch.
[0057]
The key switch thus obtained had a surface illuminating function, and had a semi-gloss-tone colored metallic glossy pattern having excellent depth and surface strength.
[0058]
【The invention's effect】
Since the present invention has the above-described configuration, it has the following effects.
[0059]
The key switch sheet is configured such that the entire surface or a partial metal thin film layer and a partial transparent coloring layer are laminated so as to have a region at least partially overlapping on the base sheet. A key switch having metallic luster of any color can be easily obtained.
[0060]
Further, the method for manufacturing a key switch according to the present invention is directed to a key switch sheet in which a metal thin film layer is partially or entirely laminated on a base sheet so as to have a region where at least a part thereof partially overlaps with a transparent coloring layer. Is installed in the molding die, the molten resin is injected into the mold, and the key switch sheet and the molten resin are integrated, so that only an arbitrary region has a metallic luster of an arbitrary color. Can be easily done.
[Brief description of the drawings]
FIG. 1 is a sectional view showing one embodiment of a key switch sheet of the present invention.
FIG. 2 is a cross-sectional view showing one step of a method for manufacturing a key switch according to the present invention.
FIG. 3 is a sectional view showing one step of a method for manufacturing a key switch according to the present invention.
FIG. 4 is a sectional view showing one step of a method for manufacturing a key switch according to the present invention.
FIG. 5 is a sectional view showing one step of a method for manufacturing a key switch according to the present invention.
FIG. 6 is a cross-sectional view showing one embodiment of the key switch sheet of the present invention.
FIG. 7 is a cross-sectional view showing one embodiment of the key switch sheet of the present invention.
FIG. 8 is a sectional view showing an embodiment of the key switch sheet of the present invention.
FIG. 9 is a cross-sectional view showing one embodiment of the key switch sheet of the present invention.
FIG. 10 is a cross-sectional view showing one embodiment of the key switch sheet of the present invention.
FIG. 11 is a sectional view showing an embodiment of the key switch sheet of the present invention.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 Key switch 2 Key switch sheet 3 Base sheet 4 Metal thin film layer 5 Transparent coloring layer 6 Anchor layer 7 Adhesive layer 10 Molding resin 11 Molding die 12 Gate

Claims (7)

A sheet for a key switch, wherein a metal thin film layer is partially or entirely laminated on a base sheet so as to have a region where at least a part thereof partially overlaps a transparent metal layer. The key switch sheet according to claim 1, wherein the transparent coloring layer is formed using a dye coloring ink, and a dye contained in the dye coloring ink sublimates and colors the surface of the base sheet. The key switch sheet according to claim 1, wherein the transparent coloring layer is formed using an ultraviolet curable ink. The key switch sheet according to claim 1, wherein the transparent colored layer is formed using a thermoplastic resin ink or a thermosetting resin ink. A key switch sheet laminated on the base sheet so as to have an area where the entire or partial metal thin film layer and the partial transparent coloring layer at least partially overlap with each other is placed in a molding die, and A method of manufacturing a key switch, comprising: injecting a molten resin into a sheet and integrating the key switch sheet and the molten resin. 6. The method for manufacturing a key switch according to claim 5, wherein a key switch sheet preformed so as to have a desired three-dimensional shape of the key switch is set in a molding die. 7. The method for manufacturing a key switch according to claim 5, wherein the overcoat layer is laminated after the sheet for the key switch and the molten resin are integrated.

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