JPH11111099A - Membrane switch having transparent part and manufacture therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a mat part excellent in transparency, water resistance, chemical resistance and abrasion resistance by forming a pattern layer on the reverse, and forming a window part by adhering a surface-delustered insert film on the same plane to a transparent resin. SOLUTION: A fine recess-projection is formed by a sand blast on a surface of a film base material 1 such as a prescribed thickness polyester film and a polycarbonate film having water resistance, chemical resistance and abrasion resistance, and delustering work is performed, and a pattern layer 2 printed by coloring ink by using a polyvinyl resin as a binder, is adhered to the reverse, and an insert film 3 is formed. A transparent part 5 is formed as a window part by punching the insert film 3, and is integrally formed on the same plane in a transparent resin 4, and a switch part 6 is worked/molded in a switch shape. Therefore, there is no need to form a mat ink layer in the film base material 1, and a characteristic of the film base material itself is imparted, and since the insert film is not interposed in the transparent part, transparency can be improved.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a membrane switch with a transparent section suitable for an input section of a rice cooker, a microwave oven, a washing machine, an audio device, and the like, and a method of manufacturing the same.

[0002]

2. Description of the Related Art Conventionally, there has been a method of obtaining a membrane switch having a matte surface and a transparent portion by using an insert molding method. The insert molding method is a method in which a pattern layer is printed on a film base material to obtain an insert film, and this is integrated with a molded product simultaneously with injection molding. The insert molding method has a feature that a pattern can be easily formed even in a molded product having a shape in which it is difficult to directly form a pattern by printing.

[0003] Specifically, first, a matte ink layer is pattern-printed on the surface of a transparent glossy film to form a matte portion, and a pattern layer is pattern-printed on the back surface to obtain an insert film. Next, a method in which an insert film is placed in an injection mold, a transparent resin is injected, and the insert film and the transparent resin are integrated to obtain a membrane switch having a transparent portion.

[0004]

However, the conventional method has the following problems.

[0005] The mat ink layer must have sufficient water resistance, chemical resistance, and abrasion strength. In order to obtain water resistance, the matte ink layer must not be made of a hydrophilic binder. In order to obtain chemical resistance, the matte ink layer must not dissolve or swell with each chemical. Also,
To obtain abrasion strength, the matte ink layer must be hard and tough. Further, when the membrane switch is used for a rice cooker or a microwave oven, the mat ink layer must be a material having no problem for food safety. Therefore, the selection range of the material for the matte ink layer that satisfies all these characteristics is narrow. Further, even if these characteristics are satisfied, if the switch portion requires matting, the mat ink layer must further have sufficient flexibility to withstand a spot test, and this characteristic is inconsistent with the abrasion strength.

Further, by printing an ink layer such as an adhesive layer on the back surface of the insert film, the transparency of a transparent portion such as a window becomes insufficient. Therefore, a transparent acrylic resin having excellent transparency is used as a molding resin. However, the transparency of the transparent portion may still be insufficient. For the film substrate, in terms of switch characteristics and cost, a polyester film of 100 to 250 μm in thickness is often used.However, the transparency is inferior to that of a transparent acrylic resin. This is because the adhesive to be adhered also causes a decrease in transparency.

Therefore, the present invention solves the above-mentioned problems, has high transparency of the transparent portion, has sufficient water resistance,
It is an object of the present invention to provide a membrane switch with a transparent portion having a mat portion having chemical resistance and abrasion strength, and a method for manufacturing the same.

[0008]

SUMMARY OF THE INVENTION In order to achieve the above object, a method of manufacturing a membrane switch with a transparent part according to the present invention is configured as follows.

That is, in the membrane switch with a transparent portion of the present invention, an insert film in which a mat is formed on the surface by fine irregularities and a pattern layer is formed on the back surface and a window portion is formed is adhered on a transparent resin, The structure was such that the surface of the film and the transparent portion of the transparent resin were formed flush.

In the above invention, the transparent resin may have a cubic curved surface.

Further, the method of manufacturing a membrane switch with a transparent portion according to the present invention is directed to a method for manufacturing an insert film in which a surface of a film substrate is matted by fine irregularities, a pattern layer is formed on the back surface, and a window portion is formed. , And placed in an injection mold so that the insert film and the transparent resin were integrated.

Further, in the above invention, an insert film previously processed to have a cubic curved surface may be used.

[0013]

Embodiments of the present invention will be described in detail with reference to the drawings.

FIGS. 1 to 3 are cross-sectional views showing one embodiment of a membrane switch with a transparent part obtained by the method for manufacturing a membrane switch with a transparent part of the present invention. In the figure, 1 is a film substrate, 2 is a design layer, 3 is an insert film, 4 is a transparent resin, 5 is a transparent portion, 6 is a switch portion, and 7 is a three-dimensional processed portion.

The membrane switch with a transparent portion according to the present invention has an insert film 3 having a matte surface formed by fine irregularities on the surface, a design layer 2 formed on the back surface, and a window portion.
Are adhered on the transparent resin 4, and the surface of the insert film 3 and the transparent portion 5 of the transparent resin 4 are formed flush. In addition, the method for manufacturing a membrane switch with a transparent portion according to the present invention includes an insert film 3 in which a surface of a film substrate 1 is matted by fine irregularities, a pattern layer 2 is formed on a back surface, and a window portion is formed. The insert film 3 and the transparent resin 4 are integrated in an injection molding die (see FIGS. 1 to 3).

The film substrate 1 needs to have water resistance, chemical resistance, and abrasion strength. When the membrane switch with a transparent portion is used for a rice cooker, a microwave oven, or the like, a switch having food safety is used. In particular, a polyester film with a thickness of 100 to 250 μm, which has excellent mechanical strength that can withstand resistance tests such as
A polycarbonate film having a thickness of 50 to 200 μm is suitable.

The matting process using the fine irregularities is performed on the surface of the film substrate 1. As a matting method, there is a method of forming fine irregularities physically by sandblasting, or a method of forming fine irregularities chemically by dipping in a strong alkaline solution. The matte surface is not expressed by the ink layer, but by matting the film substrate 1 itself, so that the matte ink layer becomes unnecessary, and the selection of the material only needs to consider the film substrate 1 alone. Will be. Even if the switch unit 6 requires matting,
Various properties such as a spot test are the same as those of the glossy film substrate 1. This is because the film substrate 1 expresses the matte surface, and various characteristics match those of the film substrate 1 itself.

The design layer 2 is formed on the back surface of the film substrate 1, that is, on the transparent resin 4 side. The design layer 2 is usually formed as a printing layer. As a material of the printing layer, a resin such as a polyvinyl resin, a polyamide resin, a polyester resin, an acrylic resin, a polyurethane resin, a polyvinyl acetal resin, a polyester urethane resin, a cellulose ester resin, and an alkyd resin is used as a binder. It is preferable to use a coloring ink containing a pigment or dye of an appropriate color as a coloring agent. As a method for forming the printing layer, a normal printing method such as an offset printing method, a gravure printing method, or a screen printing method may be used. In particular, an offset printing method or a gravure printing method is suitable for performing multicolor printing and gradation expression. In the case of a single color, a coating method such as a gravure coating method, a roll coating method, and a comma coating method can be adopted. The printing layer may be provided entirely or partially depending on the design to be expressed.

The design layer 2 may form a part of the design using an ink that produces a metallic luster by screen printing. The design layer 2 may be formed of a metal thin film layer or a combination of a print layer and a metal thin film layer. The metal thin film layer is for expressing metallic luster as the design layer 2, and is formed by a vacuum evaporation method, a sputtering method, an ion plating method, a plating method, or the like. Metals such as aluminum, nickel, gold, platinum, chromium, iron, copper, tin, indium, silver, titanium, lead, and zinc, and alloys or compounds thereof are used according to the metallic luster color to be expressed. As an example of forming a partial metal thin film layer, after forming a solvent-soluble resin layer in a portion that does not require a metal thin film layer, a metal thin film is entirely formed thereon, and solvent cleaning is performed. There is a method of removing an unnecessary metal thin film together with the solvent-soluble resin layer. The solvent often used in this case is water or an aqueous solution. As another example, there is a method in which a metal thin film is formed on the entire surface, a resist layer is formed on a portion where the metal thin film is to be left, and the resist layer is removed by etching with an acid or an alkali. . When the metal thin film layer is provided, a front anchor layer or a rear anchor layer may be provided in order to improve the adhesion between another layer and the metal thin film layer. As the material of the front anchor layer and the rear anchor layer, two-component cured urethane resin, thermosetting urethane resin, melamine resin, cellulose ester resin, chlorine-containing rubber resin, chlorine-containing vinyl resin, acrylic resin, epoxy It is preferable to use a resin such as a vinyl resin or a vinyl copolymer resin. As a method of forming the front anchor layer and the rear anchor layer, a gravure coating method,
There are coating methods such as a roll coating method and a comma coating method, and printing methods such as a gravure printing method and a screen printing method.

Further, an adhesive layer may be formed as required. The adhesive layer is a layer for bonding the insert film 3 to the transparent resin 4. As the adhesive layer, a heat-sensitive or pressure-sensitive resin suitable for the transparent resin 4 is appropriately used. For example, when the transparent resin 4 is an acrylic resin, an acrylic resin may be used. When the transparent resin 4 is a polyphenylene oxide / polystyrene resin, a polycarbonate resin, a styrene copolymer resin, or a polystyrene blend resin, an acrylic resin, a polystyrene resin, or a polyamide resin having an affinity for these resins. Etc. should be used. Further, when the transparent resin 4 is a polypropylene resin, a chlorinated polyolefin resin, a chlorinated ethylene-vinyl acetate copolymer resin, a cyclized rubber, and a coumarone indene resin can be used. Examples of a method for forming the adhesive layer 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. The dry film thickness of the adhesive layer is 0.5 to
Generally, it is 10 μm.

The transparent portion 5 is formed as a window together with the film substrate 1 of the insert film 3. Examples of a method of forming the window include a Thomson punching method and a die press punching method. In addition, the outer periphery of the insert film 3 may be shaped by punching or the like at the same time as forming the window. The window of the insert film 3 becomes the transparent part 5 after molding. Since the transparent portion 5 exposes the transparent resin 4 after the insert molding, the characteristics of the transparent resin 4 can be utilized as it is. The transparent portion 5 is for disposing a liquid crystal panel, an LED, and the like behind the membrane switch so that they can be seen. Since the insert film 3 is not interposed in the transparent portion 5, the transparent portion 5 is preferably excellent in transparency. It becomes something.

The insert film 3 thus obtained
In order to obtain a membrane switch with a transparent part by using the following method, the following may be performed.

First, the insert film 3 is disposed between the core mold having the transparent resin 4 injection port and the cavity mold having the concave portion. Next, the cavity mold and the core mold are clamped to form a closed space between the insert film 3 and the core mold. The molten transparent resin 4 is injected into this space,
If the cavity mold and the core mold are opened, a membrane switch with a transparent portion in which the insert film 3 and the transparent resin 4 are integrated can be obtained. In order to prevent the transparent resin 4 from going to the front side of the molded product from the window of the insert film 3, the position of the gate is appropriately adjusted and the transparent resin 4 is removed.
May be adjusted.

When the shape of the molded product is three-dimensional (see FIGS. 2 and 3), the insert film 3 is three-dimensionally formed to prevent the transparent resin 4 from flowing from the window of the insert film 3 to the front side of the molded product. It is preferable that the insert film 3 is preformed into a shape so that the insert film 3 is in close contact with the mold. In order to preform the insert film 3, first, the insert film 3 is fixed to a preforming mold having a concave portion by means such as a clamp, and then the insert film 3 is heated and softened by a heat source, and the preforming mold side is used. Vacuum suction is applied to the surface of the preforming die. Next, the vacuum suction is released, and the insert film 3 is taken out of the preforming die.

In this way, the preformed insert film 3 is punched into a desired shape by a Thomson mold, a press die, or the like, and the insert film 3 from which the transparent portion 5 and the unnecessary portion on the outer periphery are removed can be obtained. Since the insert film 3 has a printing ink layer on only one side of the film substrate 1, even when the insert films 3 are overlapped, a so-called blocking phenomenon in which the ink layers adhere to each other does not occur. In addition, since printing is performed only on one side of the film substrate 1, dust is unlikely to occur, and the problem of poor printing hardly occurs.

Next, the preformed insert film 3 is disposed between a core mold having a transparent resin 4 injection port and a cavity mold having a concave portion. Next, the cavity mold and the core mold are clamped to form a closed space between the insert film 3 and the core mold. By injecting the molten transparent resin 4 into this space and opening the cavity mold and the core mold,
It is possible to obtain a membrane switch with a transparent portion in which the insert film 3 and the transparent resin 4 are integrated.

The switch section 6 is formed by disposing the film substrate 1 on a female die processed into a switch shape, and pressing the film base 1 from above with a hot rubber pad to form the switch shape.
The male and female shapes of the injection mold may be processed into a switch shape, and the film base material 1 may be processed into a switch shape by a mold clamping pressure, a method of embossing into a switch shape with a press die, or the like.

[0028]

【Example】

Example 1 A polyethylene terephthalate film having a thickness of 125 μm was used as a base film, and its surface was subjected to matting by sandblasting.

On the back surface of the base film, characters are printed as a design layer with a black polyester resin ink containing 10% by weight of carbon black, containing 2% by weight of carbon black and 15% by weight of titanium oxide. Pattern 1 is printed with a gray polyester resin ink, and Pattern 2 is printed with a white-blue polyester resin ink containing 2% by weight of phthalocyanine blue and 15% by weight of titanium oxide, and contains 20% by weight of titanium oxide. The light-shielding and hiding layer was printed with a white polyester resin-based ink. Further, an adhesive layer was formed with a vinyl chloride resin-based ink.

Next, a window was formed in a portion corresponding to the transparent portion by a Thomson punching method to obtain an insert film.

The insert film thus obtained is placed in a mold for injection molding, insert molding is performed using a transparent polymethyl methacrylate resin as a molding resin, and a transparent portion, which is a radio and CD player display portion, is provided. A membrane switch was obtained.

The thus obtained membrane switch with a transparent portion had a transparent portion having excellent transparency and a mat portion having excellent water resistance, chemical resistance and abrasion strength.

Example 2 A polyethylene terephthalate film having a thickness of 188 μm was used as a substrate film, and its surface was subjected to a matting process by a sandblast method.

On the back side of the base film, characters are printed as a design layer with a black polyester resin ink containing 10% by weight of carbon black, and 2% by weight of fast yellow and 25% by weight of aluminum powder are contained. Print pattern 1 with gold polyester resin ink
Pattern 2 with a pink polyester resin ink containing 2% by weight of brilliantamine and 15% by weight of titanium oxide
And a light-shielding layer was printed with a white polyester resin-based ink containing 20% by weight of titanium oxide. further,
An adhesive layer was formed with a vinyl chloride resin-based ink to obtain an insert film.

Next, in order to make the insert film conform to a three-dimensional shape having a curvature of R300, the insert film is preformed into a shape by vacuum forming, and a rectangular window is punched out with a press die. Formed.

The preformed insert film is placed in a mold for injection molding, insert molding is performed using a transparent acrylonitrile butadiene styrene copolymer resin as a molding resin, and a three-dimensional rice cooker having a curvature of R300. A transparent section-attached membrane switch as an input display section was obtained.

The membrane switch with a transparent part obtained in this way had a transparent part with excellent transparency and a mat part with excellent water resistance, chemical resistance, abrasion strength and food safety. .

[0038]

Since the present invention has the above-described structure, it has the following effects.

The membrane switch with a transparent portion according to the present invention is characterized in that an insert film in which a mat is formed on the surface by fine irregularities, a pattern layer is formed on the back surface, and a window is formed,
It is bonded on a transparent resin, and the surface of the insert film and the transparent portion of the transparent resin are formed flush. Therefore, since the film is not located in the transparent part and the ink layer does not exist in the matte part, it has a transparent part excellent in transparency, and a mat part excellent in water resistance, chemical resistance and abrasion strength. This is a membrane switch with a transparent part.

The method of manufacturing a membrane switch with a transparent portion according to the present invention is characterized in that a matte process is performed on the surface of the film substrate by fine irregularities, a design layer is formed on the back surface, and an insert film having a window portion is formed. Is disposed in an injection molding die, and the insert film and the transparent resin are integrated. Therefore, it is possible to easily obtain a membrane switch with a transparent portion having a transparent portion having excellent transparency and a mat portion having excellent water resistance, chemical resistance and abrasion strength.

[Brief description of the drawings]

FIG. 1 is a cross-sectional view showing one embodiment of a membrane switch with a transparent part obtained by the method for manufacturing a membrane switch with a transparent part of the present invention.

FIG. 2 is a cross-sectional view showing another embodiment of a membrane switch with a transparent part obtained by the method for manufacturing a membrane switch with a transparent part of the present invention.

FIG. 3 is a cross-sectional view showing another embodiment of a membrane switch with a transparent portion obtained by the method for manufacturing a membrane switch with a transparent portion of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Film base material 2 Pattern layer 3 Insert film 4 Transparent resin 5 Transparent part 6 Switch part 7 Three-dimensional processing part

Claims (4)

[Claims] An insert film in which a mat is formed on the surface by fine irregularities and a pattern layer is formed on the back surface and a window is formed is adhered on a transparent resin, and the surface of the insert film and the transparent portion of the transparent resin are bonded to each other. A membrane switch with a transparent portion, characterized by being formed flush. 2. The membrane switch according to claim 1, wherein the transparent resin has a cubic curved surface. 3. An insert film in which a matte process is performed on a surface of a film substrate by fine irregularities, a pattern layer is formed on a back surface, and a window portion is formed, is placed in an injection mold, and the insert film is formed. A method for manufacturing a membrane switch with a transparent portion, wherein the membrane switch is integrated with a transparent resin. 4. The method for manufacturing a membrane switch with a transparent part according to claim 3, wherein an insert film previously processed to have a cubic curved surface is used.