JPH07130245A - Manufacture of cover member for illuminated push button switch - Google Patents

Abstract

PURPOSE:To efficiently and easily manufacture an illuminated push button switch cover of high quality by integrally molding a key top, push button switch cover member, light shielding colored layer, translucent colored layer, etc., of a required composition. CONSTITUTION:A transparent or translucent liquid-state silicone rubber composition with viscosity by a rotor viscometer of 1000 to 3000 poise is vacuum compression molded to form a key top 4. A push button switch cover member 1 comprising this key top 4, thin thickness part 5, base part 6, etc., light shielding colored layer 2 of thin film molded from a liquid-state silicone rubber composition with viscosity of 500 to 100 poise, very thin translucent colored layer 3, etc., are molded to be integrally formed by using a metal mold or the like, to form a cover member. Then, an illuminated push button switch cover of high quality in good appearance can be manufactured efficiently and easily in a short time.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a cover member for an illuminated push button switch, and more particularly, an illuminated push button having a high-class feeling, which is formed by integrally molding a cover member for a push button switch, a light-shielding colored layer and a translucent colored layer. The present invention relates to a method for manufacturing a switch cover member.

[0002]

2. Description of the Related Art A rubber switch cover member is often used for a push button portion of a push button switch, and since this cover member has an excellent exterior and a large number of key portions are integrally formed, Widely used for input in industrial equipment. In this type of rubber switch cover member, as shown in FIG. 6A, a conductive contact portion 26 is provided on a base body 25 including a key top portion 22, a thin portion 23 and a base portion 24. Although it is supposed to be, in order to confirm whether the push button switch is pressed firmly,
In addition, in order to improve operability in a dark place, an illumination type in which a light source is placed on the back of the transparent or semitransparent light transmitting part is also made.

A method for manufacturing the illuminated push-button switch cover member 21 is, for example, as shown in FIGS. 6 (b) to 6 (d), which is shown in FIG. 6 (b) as shown in FIG. 6 (b). a)
A transparent colored layer 27 is provided on the top surface of the key top portion of the push button switch cover member shown in FIG. 6, and a light shielding layer 28 is coated on the surface of the substrate 25 as shown in FIG. As shown in FIG. 6D, the light-shielding layer 28 is irradiated with laser light and a light-transmitting portion 29 is provided there.

[0004]

However, in this conventionally known method for manufacturing a cover member for an illuminated pushbutton switch, the character display portion of the cover member for a pushbutton switch is mainly formed by screen printing or painting. With the method, the character display part rises on the top surface of the key top part, this character display part collapses and becomes thin, warpage and chipping are likely to occur, and there is a step on the top surface of the key top part, so the appearance,
It has the drawback that it does not look good in terms of design, and if the number of character display colors increases, the painting process will increase, the work efficiency will deteriorate, the cost will increase, and the quality will also be trash.
There is a disadvantage that defects often occur due to the adhesion of foreign matter.

Further, in this conventional method, a light-shielding colored layer is also applied to this, but the character display portion is formed by removing it by irradiating a laser beam. Due to the variation in the energy of the marker, the light-shielding colored layer may remain, or even the light-transmitting coloring layer may be partially removed, and the shade of the light-transmitting coloring layer makes the appearance unsightly. It is difficult to control the manufacturing conditions such as the layer thickness and the energy setting of the laser marker, and the yield is remarkably reduced.

[0006]

The present invention relates to a method of manufacturing a cover member for an illuminated pushbutton switch which solves the above disadvantages and drawbacks, and has a viscosity of 1,000 to 3,000 poise measured by a rotor viscometer. Is a transparent or semi-transparent liquid silicone rubber composition formed by vacuum compression molding, and is a cover member for a push button switch composed of a key top portion, a thin portion and a base portion, a thin light-shielding colored layer, and an extremely thin light-transmitting property. It is characterized by being integrally molded with a colored layer.

That is, the present inventor has conducted various studies to develop a method for producing a cover member for an illuminated pushbutton switch which has solved the above-mentioned problems. As a result, a liquid silicone rubber composition was vacuum-compressed. When molded into a cover member for a push button switch, a liquid silicone rubber composition of the same kind as this is compression molded, thinly molded and transferred to form a light-shielding colored layer and a transparent colored layer, and these are integrally molded. We have found that we can obtain a cover member for illuminated pushbutton switches with a good yield, and because this shortens the process, we confirmed that the target illuminated pushbutton switch cover member can be obtained easily and at low cost. Then, the present invention was completed. This will be described in more detail below.

[0008]

The present invention relates to a method of manufacturing a cover member for an illuminated push-button switch, which is of the same type as a cover member for a push-button switch, which is made of liquid silicone rubber and includes a key top portion, a thin portion and a base portion. When the light-shielding colored layer and the light-transmitting colored layer made of the liquid silicone rubber are molded in a mold, these are co-crosslinked to obtain an intended illuminated pushbutton switch cover member as an integrated molded body. The cover member for an illuminated pushbutton switch obtained by the present invention is the one shown in FIG. FIG. 1 exemplifies a longitudinal sectional view of an illuminated push button switch cover member obtained by the present invention. The illuminated push button switch cover member 1 is formed by compression molding a light-shielding colored liquid silicone rubber composition. The light-shielding colored layer 2 and the light-transmitting colored layer 3 formed by transferring and heat-molding the colored liquid silicone rubber composition are prepared in advance, and then the transparent or translucent liquid silicone rubber is used for the key top portion 4, Substrate 7 composed of thin portion 5 and base portion 6
The light-shielding colored layer 2 and the light-transmitting colored layer 3 may be integrally molded in a mold when vacuum compression molding is performed. However, this is provided with a conductive contact portion 9 if necessary. Good.

The light-shielding colored layer 2 is preferably made of a liquid silicone rubber composition so that it can be applied to various types of key tops. Viscosity in total is 500 to 1,000
It should be made from poises, preferably 600-700 poises. As shown in FIG. 2A, this product may be discharged to the key top portion of the engraving die 10 and compression-molded. This discharge is a mechanism for quantitatively extruding the light-shielding colored liquid silicone rubber composition 12. The dispenser 16 may be used. The light-shielding colored liquid silicone rubber composition discharged to the key top portion of this engraving mold 10 is shown in FIG.
As shown in FIG. 2B, a thin film of a light-shielding colored layer having a thickness of about 50 to 180 μm is formed by compression molding using the light-shielding part molding die 11 as shown in FIG. To be done.

[0010] The light-shielding colored liquid silicone rubber composition is quantitatively extruded by a syringe type which is determined by the air pressure value and the time during which compressed air is applied, a tank valve type or a genbang type which is determined by the constant air pressure value and the passage opening time, A known control method of pulling in and pushing out, such as a rotary type, a gap pump type, or a plunger type, may be used, and the required fixed amount discharge accuracy at this time is a repeat accuracy superior to ± 0.01 ml. Further, compression molding of this light-shielding colored liquid silicone rubber composition is 100 to 200 kg / cm ² ,
Mold transfer may be performed under the condition of 120 to 150 ° C. In order to improve the moldability of this liquid silicone rubber composition and to leave it in the engraving mold 10 after molding, the light shielding part molding mold 11 It is advisable to set a draft of 2 to 5 ° C. on this side and perform plating for releasing, or apply a releasing agent in advance.

Next, the production of the light-transmitting colored layer 3 may be carried out by molding a liquid silicone rubber composition on the light-shielding colored layer 2 on the engraving die 10 described above. As shown in (a), the translucent colored liquid silicone rubber composition 17 is pulled up from the storage tank 14 and dropped with a pin 13, and then, as shown in FIG. The liquid silicone rubber composition dripped on is compressed and molded by the light-transmitting part molding die 15, and this is molded as the light-transmitting colored layer 3 as shown in FIG. 3 (c). The translucent colored layer 3 is transferred by the pin 13 that supplies the liquid silicone rubber composition 17, but if the viscosity is high, stringing occurs and it is easy to adhere to unnecessary portions. The viscosity meter should be 20 to 100 poise, preferably 40 to 60 poise, but if this is hardened early due to the shape of the key top and the molding temperature, add 8 to 10% of a control agent to cure it. It is better to slow down.

The thickness of the transparent colored layer is 40 to 80 μm in advance for the clearance between the transparent portion molding die 15 and the engraving die 10.
m, preferably 50 to 60 μm, and the translucent colored liquid silicone rubber composition 17 is transferred to the light-shielding colored layer 2 on the engraved mold 10 to reduce the weight of the transparent part molding die 15 only. If it is heated and molded with load (120-150 ℃), the thickness will be 50-60μ
The transparent colored layer of m is formed.

The light-shielding colored liquid silicone rubber composition 12 and the light-transmitting colored silicone rubber composition 17 described above are produced by mixing the liquid silicone rubber composition and the coloring agent with an Oble roll, a kneader, a chopper colloid mill,
Mixing can be done with a general mixer such as a ball mill, homogenizer, three rolls, or blade-type stirrer, but this does not cause the crosslinking reaction to grow significantly, and it is necessary to mix under mild conditions, so stirring that occurs during stirring In order to suppress the heat as much as possible, it is preferable to stir with a blade stirrer at a speed of 200 to 500 rpm.

The liquid silicone rubber composition for forming the base 7 in the illuminated push-button switch cover member 1 of the present invention is an addition reaction type composition comprising vinyl siloxane, an organohydrogenpolysiloxane and a platinum-based catalyst. A liquid silicone rubber composition is preferable, and this molding is preferably vacuum compression molding in a mold. The liquid silicone rubber composition used here has a hardness of 80 or less at 1 RHD after being molded and crosslinked, a rebound resilience of 70% or more, an elongation of 200% or more, a tensile strength of 60% or more, a compression set. Is less than 20% (150 ℃, 22
However, the viscosity of this liquid silicone rubber composition is measured by a rotor viscometer in the range of 1,000 to 3,000 poise, preferably 1,500 to 2,500.
Poisoned.

The molding of the base material 7 from this liquid silicone rubber composition is carried out by engraving the liquid silicone rubber composition 19 from the dispenser 16 as shown in FIG. 2. The liquid silicone rubber composition 19 may be dropped onto the translucent colored layer 3.
As shown in Fig. 4 (b), the degree of vacuum is 0.
When molded under the conditions of 7 to 0.9 Torr, 100 to 200 kg / cm ² , 120 to 150 ° C., this is molded into the push button switch cover member 7 as shown in FIG. The light-transmitting colored layer 3 is cross-linked to form the illuminated push-button switch cover member 1 of the present invention.

Since the cover member for the illuminated push-button switch molded in this way is not provided with the light transmitting portion 8 shown in FIG. 1, it is formed by irradiating a laser marker by a known method. It is necessary to manufacture the illuminating light produced by integrally molding the light-shielding coloring layer 2, the light-transmitting coloring layer 3 and the substrate 7 which are produced by the method shown in FIG. 4 as shown in FIG. After passing the light flux from the laser marker 20 (for example, Nd: YAG laser) through the mask of the code shape desired to be the light-transmitting portion, the light-shielding colored layer 2 of the cover member for the push-button switch is focused by the lens, Alternatively, a laser beam that is narrowed down may be scanned into a shape of a different sign that is used as a light-transmitting portion and irradiated.

[0017]

EXAMPLES Next, examples of the present invention will be given. KE as an addition reaction type liquid silicone rubber composition material
-1935A / B [Shin-Etsu Chemical Co., Ltd. product name] A and B
After mixing and in a ratio of 100: 100, 10 parts by weight of a coloring agent for silicone rubber, K-Color-BK-02 [trade name of Shin-Etsu Chemical Co., Ltd.] was added to 100 parts by weight of the mixture, The mixture was rotatively mixed at 500 rpm with a stirrer to prepare a light-shielding colored liquid silicone rubber composition 12 having a viscosity of 700 poise at 25 ° C.

Then, the light-shielding colored liquid silicone rubber composition 12 is injected into a syringe, and 1 g is discharged from the syringe to the engraving die 10 using a dispenser 16, and the light-shielding portion forming die 11 is overlaid and closed. To 150 kg / cm ² , 120
When heat-molded under pressure at 1 ° C. for 1 minute and 30 seconds, it was cured and molded into a thin film substrate shape, and a thin film light-shielding colored layer 2 having a top surface thickness of 180 μm and 20 keys in series was obtained.

Further, as a non-filler type liquid silicone rubber composition material of addition reaction type liquid silicone rubber composition, KE-106 [trade name of Shin-Etsu Chemical Co., Ltd.] and catalyst CAT-RG [Shin-Etsu Chemical Industry ( Co., Ltd. product name]
When mixed at a ratio of 100: 10, the viscosity at 25 ℃ was 40
Since a liquid silicone rubber composition of Poise was obtained, 20 parts by weight of this silicone rubber colorant, K-Color-W, was added.
-10, K-Color-R-21, K-Color-GN-60 [all are trade names manufactured by Shin-Etsu Chemical Co., Ltd.] were added to 1 part by weight, and the mixture was rotated and mixed at 300 rpm with a blade stirrer. After rotating and dispersing with a triple roll at 5 rpm, three kinds of light-transmitting colored liquid silicone rubber composition 17 having different hues were obtained.

Next, the translucent colored liquid silicone rubber composition 17 is poured into the storage tank 14 for each color tone, and the liquid silicone rubber composition 17
This translucent colored liquid silicone rubber composition 17 is attached only to the tip portion using 13 and transferred to the key top portion, and 50
The transparent part molding die 15 with a clearance of μm is overlapped and closed, and the transparent colored liquid silicone rubber composition 17 is pressed by its own weight,
When heat-molded for 2 minutes under the condition of 0 ° C., this material loses fluidity in the key top portion and hardens, so that a transparent colored layer 3 having a uniform thickness of 50 μm is obtained for each color tone. .

Next, as an addition reaction type liquid silicone rubber composition material, KE1990A / B [Shin-Etsu Chemical Co., Ltd.]
[Product name] A and B were mixed in a static mixer at a ratio of 100: 100, and the viscosity at 25 ° C was 2,000.
The liquid silicone rubber composition 19 which is a poise is dispensed with a dispenser 16 and 10 g is discharged onto a die 10, and a raised die 18 is overlaid and closed, and this is 150 kg / cm ² , 120 ° C.
When vacuum pressurizing and heating were performed under a vacuum of 0.85 Torr under the conditions described above, a base 7 composed of a key top portion 4, a thin movable portion 5 and a base portion 6 was formed, which is a light shielding colored layer 2 and a transparent coloring. Since it was co-crosslinked with the layer 3 and integrally molded, it was removed from the mold to obtain a cover member in which 20 keys were arranged and provided with the light-shielding colored layer 2 and the light-transmitting colored layer 3.

The light-shielding colored layer 2 on the key top portion of the cover member having various colored layers obtained in this manner
On top of the Nd: YAG laser marker, 20SL-478U
Using the [trade name of NEC Corporation], the shape of the letter "CS" is removed and a few pulses of energy of 15 joules are radiated through the aluminum vapor-deposited glass mask to punch the light-transmitting portion 8 in the shape of the letter. When installed, a cover member for an illuminated pushbutton switch as shown in FIG. 1 was obtained.

[0023]

The present invention relates to a method of manufacturing a cover member for an illuminated pushbutton switch, which is a transparent or semitransparent liquid silicone rubber having a viscosity of 1,000 to 3,000 poise measured by a rotor viscometer as described above. A push button switch cover member comprising a key top portion, a thin portion and a base portion, which are produced by vacuum compression molding of a composition, and a thin film light-shielding colorant and an ultrathin translucent coloring layer, which are integrally formed. The light-shielding colored layer and the light-transmitting colored layer are prepared in advance, and since these are integrally molded in the mold for molding the cover member for the pushbutton switch, a short process It is possible to obtain a cover member for an illuminated push button switch that is efficient, easy, and inexpensive, has no dust, foreign matter, etc., and has improved quality and looks good. Advantage that wear is given.

[Brief description of drawings]

FIG. 1 is a vertical sectional view of an embodiment of a cover member for an illuminated push button switch obtained according to the present invention.

FIG. 2 illustrates a process of manufacturing a light-shielding colored layer in a cover member for an illuminated push-button switch obtained by the present invention, in which (a) is a vertical cross-sectional view of a quantitative extrusion mechanism of a liquid silicone rubber composition, (b) is a vertical cross-sectional view of an apparatus for compression-molding the same, and (c) is a vertical cross-sectional view of the molded light-shielding colored layer.

FIG. 3 illustrates a manufacturing process of a translucent colored layer in a cover member for an illuminated push-button switch obtained according to the present invention, in which (a) is a vertical sectional view of a dropping mechanism of a liquid silicone rubber composition; b) is a longitudinal sectional view of the compression molding device,
(C) is a vertical cross-sectional view of the molded transparent colored layer.

FIG. 4 illustrates a molding step of a method for manufacturing a cover member for an illuminated push-button switch according to the present invention, in which (a) is a vertical sectional view of a dropping mechanism of a liquid silicone rubber composition dispenser, and (b) is an embossed metal. FIG. 3C is a vertical cross-sectional view of a molding device using a mold, and FIG. 3C is a vertical cross-sectional view of the molded push button switch cover member.

FIG. 5 is a vertical cross-sectional view of an apparatus for forming a light transmitting portion on a cover member for a push button switch by irradiating a laser from a laser marker.

FIG. 6 is a diagram showing a manufacturing process of a cover member for an illuminated push-button switch according to a conventional method, in which (a) is a vertical cross-sectional view of a base body including a key top portion, a thin portion, and a base portion;
Is a vertical cross-sectional view of a light-transmissive colored layer provided thereon, (c)
Is a vertical cross-sectional view of what is coated with a light-shielding layer, and (d) is a vertical cross-sectional view of what is provided with a light transmitting portion.

[Explanation of reference numerals] 1 , 21 ... Cover member for illuminated push button switch, 2 , 28 ... Light-shielding colored layer, 3, 27 ... Translucent coloring layer, 4, 22 ... Key top portion, 5, 23 ... Thin portion , 6,24 ... Base part, 7,25 ... Base part, 8,29 ... Translucent part, 9,26 ... Conductive contact part, 10 ... Engraving mold, 11 ... Shading part molding mold, 12 ... Shading coloring Liquid silicone rubber composition, 13 ... Pin, 14 ... Translucent colored liquid silicone rubber composition storage tank, 15 ... Translucent part molding die, 16 ... Dispenser, 17 ... Translucent colored liquid silicone rubber composition, 18 ... Embossing mold, 19 ... Liquid silicone rubber composition, 20 ... Laser marker.

Claims (3)

[Claims] 1. The viscosity measured by a rotor viscometer is 1,000 to
A push button switch cover member consisting of a key top portion, a thin portion and a base portion formed by vacuum compression molding of a transparent or translucent liquid silicone rubber composition of 3,000 poise, a thin light-shielding colored layer and an ultra-thin transparent layer. A method of manufacturing a cover member for an illuminated push-button switch, which comprises integrally molding a light-colored colored layer. 2. A thin film having a thickness of 50 to 180 μm formed by compression molding of a light shielding liquid silicone rubber composition in which the light shielding colored layer has a viscosity of 500 to 1,000 poise measured by a rotor viscometer and molded by a mold. The method for manufacturing a cover member for an illuminated push button switch according to claim 1, wherein the cover member is an illuminated push button switch. 3. A translucent colored liquid silicone rubber composition whose translucent colored layer has a viscosity of 20 to 100 poise measured by a rotor viscometer, and has a thickness of 40 to 80 .mu.
The method for manufacturing a cover member for an illuminated pushbutton switch according to claim 1, wherein the cover member is an ultrathin layer of m.