JP2005005237A - Cover member for push-button switch and manufacturing method of the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a cover member for a push-button switch on which a pattern with an elegant and fine cutout letter is applied, having a key top with a specular gloss, and to provide a method of economically and stably manufacturing the cover member in mass. <P>SOLUTION: The content of an aluminum foil is 7 to 20 mass% in a printed layer for display, the thickness of 70 to 100% of the aluminum foil is 0.02 to 0.5 μm, the surface area at one surface of the aluminum foil is 20 to 1,000 μm<SP>2</SP>, the difference between a cubic volume median diameter Dv0.9 and a cubic volume median diameter Dv0.1 is not larger than 20 μm, and a cubic volume median diameter Dv0.5 is 5 μm to 20 μm. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

【００４９】
［比較例１〜３］
アルミニウム箔の厚み、面積、体積メジアン径、アルミニウム箔の比は、表１に示す内容とした。その外は実施例１と同様にした。
【００５０】
実施例２と比較例１とからは、総固形分中のアルミニウム（Ａｌ）が７質量％未満になると鏡面の光沢が得られなくなることがわかった。
【００５１】
実施例２と比較例２とからは、片面の表面積が２０〜１０００μｍ^２の範囲のアルミニウム箔含有率が７０質量％程度を境にそれより少なくなると鏡面の光沢感が得られなくなるおそれがあることがわかった。
【００５２】
実施例２と実施例３とからは、Ｄｖ０．９とＤｖ０．１との差が２０μｍを越えると箔粒子のばらつきが大きくなり、鏡面の光沢感が得られなくなるおそれがあることがわかった。
【００５３】
【発明の効果】
以上説明してきたように、請求項１又は２に記載の発明によれば、抜き文字に高品位な微細な模様加工が施され、鏡面光沢も備えたキートップを、経済的に安定的に量産可能にするミラーインク又はこのミラーインクを使用した押釦スイッチ用カバー部材が得られる。
【００５４】
請求項３又は４に記載の製造方法の発明によれば、抜き文字に高品位な微細な模様加工が施され、鏡面光沢も備えた押釦スイッチ用カバー部材として、経済的に安定的に量産可能となる。
【図面の簡単な説明】
【図１】この発明の実施の形態に係る押釦スイッチ用カバー部材のキートップ部天面の拡大断面図である。
【図２】従来の技術に係る押釦スイッチ用カバー部材のキートップ部天面の拡大断面図であり、ミラーインク中の溶剤が多い場合を示している。
【図３】従来の技術に係る押釦スイッチ用カバー部材のキートップ部天面の拡大断面図であり、ミラーインク中のバインダーが多い場合を示している。
【符号の説明】
１ ミラーインク
２ アルミニウム箔
３ 印刷部分の端部
４ アルミニウム箔の端部[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a cover member for a pushbutton switch using a mirror ink having a specular gloss capable of character printing and a manufacturing method thereof.
[0002]
[Prior art]
There are many electrical / electronic appliances equipped with pushbutton switches such as mobile phones. A cellular phone forms a case body with a synthetic resin. There is a demand from the market for the case body of mobile phones including key tops to have a metallic mirror surface in terms of design. In practice, it is necessary to add letters and other patterns.
[0003]
There are several methods for metallic processing of key tops. For example, metal deposition is performed on the key top molded body (see, for example, Patent Document 1). In this case, patterns such as letters are etched with a laser.
[0004]
Another method is to chemically etch the metal deposited film and hot stamp it on the top or bottom surface of the key top.
[0005]
There is also a method using mirror ink. Mirror ink is ink containing aluminum foil in which aluminum foil is dispersed in a solvent and a binder.
[0006]
The conventional mirror ink is composed of 100 parts by mass (3 to 14% by mass) of aluminum foil, 15 to 200 parts by mass (0.5 to 22% by mass) of a binder polymer, and 600 to 3000 parts by mass (67 to 96% by mass) of a solvent. ) Are mixed (see, for example, Patent Document 2).
[0007]
A type containing 5 to 15% by mass of an aluminum foil, 1 to 10% by mass of a binder polymer, 80 to 93% by mass of a solvent, and 1 to 10% of an auxiliary agent is also known.
[0008]
A type including 4.08% by mass of aluminum foil, 43.91% by mass of a binder polymer, and 52.01% by mass of a solvent is also known.
[0009]
[Patent Document 1]
Japanese Unexamined Patent Publication No. 2000-306453 (FIG. 1)
[Patent Document 2]
Japanese Patent No. 3151606 [Problem to be Solved by the Invention]
If laser etching is performed for letter cutting after metal deposition is performed on the key top portion, the periphery of the etching is white and the design is not very happy. In the laser etching process, the metal is partially oxidized, and the metal vapor deposition part appears to be transparent due to the change in the refractive index, but when the base is formed of a non-metallic colorant, the non-metallic colorant is not peeled off. Remain in. That is, the background color remains, and it is necessary to separately remove the non-metallic colorant portion.
[0010]
The method of chemically etching and hot stamping a metal-deposited film has a problem that the number of manufacturing steps is large and the yield is low. This leads to an increase in cost.
[0011]
Although it was possible to obtain a key top portion having a metallic luster by using a mirror ink, the conventional mirror ink had a very low viscosity in order to improve the printability, and as shown in FIG. In addition, the aluminum foil 11 positioned at the printing end 10 is not uniform (so-called ink bleeding), and it has been almost impossible to perform a minute pattern processing such as a blank character.
[0012]
Therefore, the present invention is economically stable for a push button switch cover member having a key top having a high-quality fine pattern processing of a letter and having a metallic-like mirror gloss and the push button switch cover member. It is an object of the present invention to provide a manufacturing method capable of mass production.
[0013]
[Means for Solving the Problems]
In order to achieve the above object, the invention according to claim 1 is a cover member for a pushbutton switch having one or more key top portions having a display printing layer and a base portion supporting the key top portion. The display printing layer is bonded and fixed to an aluminum foil group that is stacked in multiple layers parallel to the top surface of the key top portion, and the aluminum foil group within a range that does not substantially disturb the parallel stacked state of the aluminum foil group. And a thickness of the display print layer is 4 to 7 μm.
[0014]
In addition to the structure of Claim 1, the invention according to Claim 2 is that the aluminum foil of the display printing layer is 7 to 20% by mass, and 70 to 100% of the aluminum foil is 0.02 to 0.02% in thickness. The surface area of one surface of the aluminum foil is 20 to 1000 μm ² , and the difference between the volume median diameter Dv0.9 and the volume median diameter Dv0.1 is 20 μm or less.
[0015]
The invention of the manufacturing method according to claim 3 has a thickness of 0.02 to 0.5 μm, a surface area of one surface of 20 to 1000 μm ² , and a difference between the volume median diameter Dv0.9 and the volume median diameter Dv0.1 is 20 μm or less. And adjusting the viscosity-adjusted ink by adjusting a viscosity of 20 to 80 cp of an aluminum foil having a volume median diameter Dv0.5 of 5 to 20 μm and a binder resin of 93 to 80% by mass with a solvent. A step of printing a letter on a resin film for key-top molding, a step of backing printing with another transparent ink on the letter printing portion, a step of curing the letter printing portion and the backing printing portion, A step of preforming a molding resin film into a key top shape, and a core material forming resin filled in a key top-shaped recess formed by the preforming And a step of curing the resin.
[0016]
The invention of the manufacturing method according to claim 4 has a thickness of 0.02 to 0.5 μm, a surface area of one surface of 20 to 1000 μm ² , and a difference between the volume median diameter Dv0.9 and the volume median diameter Dv0.1 is 20 μm or less. And adjusting the viscosity-adjusted ink by adjusting a viscosity of 20 to 80 cp of an aluminum foil having a volume median diameter Dv0.5 of 5 to 20 μm and a binder resin of 93 to 80% by mass with a solvent. And a step of printing characters on the top or bottom surface of the resin key top of the cover member for the push button switch with the resin key top.
[0017]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, an embodiment of the present invention will be described.
[0018]
The mirror ink for pushbutton switches is formed of a mixture containing a solid component and a liquid component. The solid component includes an aluminum foil and a binder. The liquid component includes a solvent. The binder fluidizes when mixed with the solvent. In the mirror ink for a push button switch according to the present invention, the concept of a solid component is considered.
[0019]
The aluminum foil which is a solid component uses single aluminum or an aluminum alloy. The surface should just maintain substantially high light reflectivity (specular gloss). Specifically, a gloss level of 200 or higher is preferable.
[0020]
Most of the aluminum foil has a thickness of 0.5 μm or less, preferably 0.3 μm or less. When the thickness exceeds 0.5 μm, it is difficult to obtain sufficient mirror gloss for the key top, which is not preferable.
[0021]
Aluminum foil is typically have a flat substantially oval as a leaf, or the surface area of one side is using those 20μm ² ~1000μm ^2. If it is less than 20 μm ² , there are too many fine aluminum foils, and sufficient mirror gloss may not be obtained. If it exceeds 1000 μm ² , the dispersibility of the aluminum foil on the surface of the printed sheet immediately after printing is lacking, and as a result, it becomes difficult to obtain a mirror gloss, which is not preferable.
[0022]
In particular, 70% of the total aluminum foil is required to have a thickness of 0.5 μm or less and a surface area of one surface of the aluminum foil of ²⁰ to 1000 μm ² .
[0023]
The screen mesh of the aluminum foil is preferably 300 to 400. If the mesh is rough, the high light-reflective metal film thickness is increased, and the reflection brightness may be impaired. If the mesh is made fine, the film thickness becomes too thin. The absolute amount of the aluminum foil is insufficient, and it becomes difficult to obtain sufficient reflection brightness.
[0024]
The squeegee hardness is preferably 60-80. When the hardness is high, the mirror metal film thickness becomes small and the absolute amount of aluminum becomes insufficient, making it difficult to obtain sufficient reflected brightness.
[0025]
The volume median diameter Dv0.5 is preferably 5 to 20 μm. Here, the volume median diameter Dv0.5 means a diameter in which the volume on the large side and the small side are equal when divided into two from a certain particle diameter.
[0026]
When the volume median diameter Dv0.5 is less than 5, the particles are too small to obtain a high glossiness. If the volume median diameter Dv0.5 exceeds 20, the printability of the ink is lowered, which is not preferable.
[0027]
Other aluminum foils can be used instead of such aluminum foils. For example, 75% or more of the surface area of one side of the aluminum foil is 20 to 1000 μm ² , and the difference between the volume median diameter Dv0.9 and the volume median diameter Dv0.1 is preferably 20 μm or less.
[0028]
If the size of the aluminum foil exceeds this range in terms of volume median diameter, the dispersion of the foil particles increases, and a stable mirror surface cannot be formed, which is not preferable.
[0029]
A binder is used together with the aluminum foil. Examples of the binder include polyester, poly (meth) acrylic ester, vinyl chloride copolymer, polyurethane, and epoxy resin.
[0030]
The proportion of the aluminum foil in the total solid component is 7 to 20% by mass, preferably 10 to 15% by mass. If it is less than 7% by mass, sufficient mirror gloss may not be obtained. If it exceeds 20% by mass, the printing characteristics of the ink will be significantly inferior. Adhesiveness between the aluminum foil and the printed film is unfavorably deteriorated.
[0031]
As shown in FIG. 1, the viscosity of the mirror ink 1 for letter printing is such that the aluminum foil 2 is laminated in parallel, and the end surface of the aluminum foil 2 itself laminated at the end 3 of the printed portion. It is desirable to adjust so that 4 is aligned. Specifically, the viscosity of the mirror ink is desirably 20 to 80 cp.
[0032]
That is, when the viscosity is less than 20 cp, as shown in FIG. 2, the aluminum foil 2 quickly settles in the mirror ink 1 due to the influence of gravity due to the large amount of solvent, and thus is laminated. Since the aluminum foils 2 that are present are uneven, the end 3 of the printed portion is undesirably disturbed. On the other hand, when the viscosity exceeds 80 cp, as shown in FIG. 3, the aluminum foil 2 cannot settle quickly in the mirror ink 1 due to the large amount of binder, and the aluminum foil 2 is hardened with uneven orientation. Therefore, the direction and brightness of the reflected light of the light impinging on the aluminum foil 2 vary, and as a result, a metallic mirror gloss cannot be realized.
[0033]
The push button switch mirror ink thus obtained may be used, for example, as follows.
[0034]
The ink whose viscosity is adjusted to such an extent that it can be printed is drawn on the key top molding resin film and printed. Next, the blank printed portion is printed on the back with another transparent ink, and the blank printed portion and the printed printed portion are cured. If necessary, the extracted character portion is separately screen-printed with a colorant to obtain a desired color. On the other hand, a keytop molding resin film is preformed into a keytop shape, and a keytop-shaped recess formed by the preforming is filled with a core-forming resin that forms the core material of the keytop. By curing the resin, a cover member for a push button switch in which the outer surface of the core material of the key top is coated with a resin film is manufactured. Here, as the core-forming resin, a thermoplastic resin such as a polycarbonate resin may be used in the case of injection molding. In addition, acrylic photo-curing resin, methacrylic photo-curing resin, unsaturated polyester photo-curing resin, styrene photo-curing resin, urethane photo-curing resin, diallyl phthalate photo-curing resin, etc. Alternatively, a photocurable resin that is solidified by irradiation with visible light or the like may be used.
[0035]
Further, in order to obtain a cover member for a pushbutton switch in which a resin key top is fixed to a base portion made of an elastic material such as silicone rubber, a viscosity-adjusted ink whose viscosity is adjusted to the extent that character printing can be performed can be obtained. What is necessary is just to adhere | attach and fix to the base part of the cover member for pushbutton switches what the character was printed on the top surface or the bottom face.
[0036]
【Example】
Examples of the present invention will be described below.
[0037]
[Example 1]
Aluminum foil, a binder, and a solvent were mixed to prepare a mirror ink for a push button switch.
[0038]
As the aluminum foil, TR-2100 (trade name) manufactured by Asahi Kasei Corporation was used. The thickness was 0.2 μm, the single-sided surface area of 20 to 1000 μm ² was 92%, and Dv0.9-Dv0.1 was 15 μm.
[0039]
A polyurethane resin was used as the binder. As a solvent, 1-methoxy-2-propanol was used.
[0040]
The total amount of aluminum foil and binder was 100%, the ratio of aluminum foil was 13%, the solvent was 54.28% by mass of the total, and the three were mixed.
[0041]
In this way, a mirror ink for a push button switch was obtained. The resulting mirror ink mixture had a viscosity of 32 cp.
[0042]
The obtained mirror ink for pushbutton switches was screen-printed on a PET film having a thickness of 100 μm. At that time, the character portion was cut out and printed.
[0043]
The obtained character-extracted printed portion was printed on the back with a transparent ink. As the transmissive ink, 9300 series HIPET ink (manufactured by Jujo Chemical Co., Ltd.) was used. The film was dried at 120 ° C. for 1 hour to obtain a molded film original.
[0044]
The obtained molded film original fabric was then preformed into a key top shape to obtain a key top covering member. Specifically, a key top with letters was obtained by injecting polycarbonate resin as a covering member for the key top.
[0045]
There was an excellent specular gloss, no white border around the letters, and there was no inadvertent popping of the base color. It was found that a key top having a mirror gloss film with a fine character pattern processing can be obtained economically with a small number of processes.
[0046]
[Example 2]
The thickness, area, volume median diameter, and aluminum foil ratio of the aluminum foil were as shown in Table 1, and 5 parts by mass of polyurethane resin was added to 100 parts by mass of the mirror ink as a thickener. Others were the same as in Example 1. The viscosity was 50 cp. Along with the numerical values of Example 1, the necessary numerical values regarding the ink blending examples are shown in Table 1.
[0047]
Appropriate specular gloss was adjusted by adding a thickener.
[0048]
[Table 1]

[0049]
[Comparative Examples 1-3]
The thickness, area, volume median diameter, and aluminum foil ratio of the aluminum foil were as shown in Table 1. The others were the same as in Example 1.
[0050]
From Example 2 and Comparative Example 1, it was found that when the aluminum (Al) in the total solid content was less than 7% by mass, the gloss of the mirror surface could not be obtained.
[0051]
From Example 2 and Comparative Example 2, when the aluminum foil content in the range of the surface area on one side of 20 to 1000 μm ² is less than about 70% by mass, the glossiness of the mirror surface may not be obtained. I understood.
[0052]
From Example 2 and Example 3, it was found that when the difference between Dv0.9 and Dv0.1 exceeds 20 μm, the dispersion of the foil particles increases, and the glossiness of the mirror surface may not be obtained.
[0053]
【The invention's effect】
As described above, according to the first or second aspect of the present invention, a key top having a high-quality fine pattern processed on a cut character and having a mirror surface gloss can be mass-produced economically and stably. A mirror ink to be made available or a cover member for a push button switch using this mirror ink is obtained.
[0054]
According to the invention of the manufacturing method of claim 3 or 4, mass production can be economically and stably as a cover member for a pushbutton switch in which a high-quality fine pattern processing is applied to a drawn character and mirror gloss is provided. It becomes.
[Brief description of the drawings]
FIG. 1 is an enlarged cross-sectional view of a top surface of a key top portion of a cover member for a push button switch according to an embodiment of the present invention.
FIG. 2 is an enlarged cross-sectional view of the top surface of a key top portion of a cover member for a push button switch according to the prior art, showing a case where the solvent in the mirror ink is large.
FIG. 3 is an enlarged cross-sectional view of the top surface of a key top portion of a cover member for a push button switch according to the prior art, showing a case where the binder in the mirror ink is large.
[Explanation of symbols]
1 Mirror ink 2 Aluminum foil 3 Edge of printed part 4 Edge of aluminum foil

Claims (4)

A cover member for a pushbutton switch having one or more key top portions having a display print layer and a base portion supporting the key top portion, wherein the display print layer is disposed on a top surface of the key top portion. A group of aluminum foils that are stacked in parallel and a binder resin that adheres and fixes the aluminum foil groups within a range that does not substantially disturb the parallel stacked state of the aluminum foil groups, and the thickness of the display printing layer is 4 A cover member for a pushbutton switch, characterized in that it is -7 μm. The aluminum foil of the display printing layer is 7 to 20% by mass, 70 to 100% of the aluminum foil is 0.02 to 0.5 μm in thickness, and the surface area of one surface of the aluminum foil is 20 to 1000 μm ² . 2. The pushbutton switch cover member according to claim 1, wherein the difference between the median diameter Dv0.9 and the volume median diameter Dv0.1 is 20 μm or less, and the volume median diameter Dv0.5 is 5 to 20 μm. Thickness 0.02 to 0.5 μm, single-sided surface area 20 to 1000 μm ² , difference between volume median diameter Dv0.9 and volume median diameter Dv0.1 is 20 μm or less, and volume median diameter Dv0.5 is 5 to 20 μm The step of adjusting the aluminum foil 7-20% by mass and the binder resin 93-80% by mass with a solvent to a viscosity of 20-80 cp, and the step of printing the letter-adjusted ink on a key top molding resin film And a step of backing printing with the other transparent ink on the blank character printing portion, a step of curing the blank character printing portion and the backing printing portion, and pre-molding the molding resin film into a key top shape. A push button comprising: a step, and a step of filling a core-forming resin into a key-top-shaped recess formed by preforming and curing the core-forming resin A method of manufacturing a switch cover member. Thickness 0.02-0.5 μm, single-sided surface area 20-1000 μm ² , difference between volume median diameter Dv0.9 and volume median diameter Dv0.1 is 20 μm or less, and volume median diameter Dv0.5 is 5-20 μm And adjusting the viscosity of the aluminum foil 7-20% by mass and the binder resin 93-80% by mass with a solvent to a viscosity of 20-80 cp, and the resin key of the cover member for a pushbutton switch with a resin key top. And a step of printing a letter on the top or bottom surface of the top.

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