JP2889899B2 - Method for manufacturing concave molded body and method for manufacturing cover member for push button switch - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a concave molded article and a method for producing a cover member for a push button switch, and more particularly to various caps and containers made of a curable (often thermosetting) liquid resin. And a method of manufacturing a cover member for a push button switch used in an input section of a home appliance such as a remote controller, a calculator, a telephone, and an OA device.

[0002]

2. Description of the Related Art Conventionally, in the production of a concave molded body from a thermosetting liquid resin, as shown in FIG. 3A), a liquid resin 22 is formed into a concave shape set at a temperature at which the liquid resin is cured.
It is carried out by filling the space between the molds 23 having a single-sheet structure, closing the mold as shown in FIG. 3B) and curing by compression molding to obtain a concave molded body 21 as shown in FIG. 3C). ing.

As a cover member for a push button switch, a key top portion made of a thermosetting liquid resin, and a thin movable portion made of a rubber-like elastic body and a base portion are integrally formed with the key top portion is known. This is shown in Fig. 4A)
As shown in the figure, the thermosetting liquid resin 32 is filled into the cavity 33 of the key top forming portion of the mold, and when the entire liquid resin loses fluidity, the thin movable portion of the mold, the base portion The cavity of the forming portion is filled with the rubber-like elastic body 34, and these are thermoset integrally formed by compression molding, injection molding, transfer molding, or the like, and the key top portion is formed as shown in FIG. 4C).
35, a push button switch cover member 31 including a thin movable portion 36 and a base portion 37.

[0004]

However, in the case where it is necessary to form a concave-shaped molded body having the same outer diameter and a different wall thickness or a material made of a different material by using the conventionally known manufacturing method, it is necessary to use these materials. Since the heat yield ratio of the molds must be different, the mold size must be changed accordingly. Had the disadvantage that it needed to be modified.

In the cover for a push button switch, since a thermosetting liquid resin constituting a key top portion tends to shrink during thermosetting, a gap is formed between the cavity and the hardened liquid resin. Since the uncured rubber-like elastic material to be filled later enters into the gap, a part of the key-top part which should be originally formed of a liquid resin is formed of the rubber-like elastic material, and the key-top is formed. The size of the part is smaller than that of the mold, so that there is a disadvantage that a stable product cannot be obtained in terms of quality.

[0006]

SUMMARY OF THE INVENTION The present invention relates to a method of manufacturing a concave molded product and a cover member for a push button switch which solves such disadvantages, disadvantages and problems. Pours curable resin in a liquid state into a concave mold, only the portion of the resin in contact with the mold is cured, and when the central part is in a fluid state, only the resin in the central part is removed and the mold is removed. After the remaining resin loses adhesiveness, the uncured rubber-like elastic body is filled in the center, the uncured rubber-like elastic body and the resin are cured, and only the portion composed of the rubber-like elastic body is removed. This method of manufacturing a cover member for a push button switch is characterized in that a curable resin in a liquid state is poured into a key top forming cavity, and only a portion in contact with the resin cavity is cured, and the center is hardened. The part is flowing In the state, the resin in the central portion is removed, and the uncured rubber-like elastic body is filled in the cavity of the central portion, the thin movable portion, and the base portion forming portion, and is integrally molded. It is.

That is, the present inventors have conducted various studies on a method of manufacturing a concave molded product and a cover member for a push button switch which can solve the disadvantages and disadvantages of the conventional method. In molding the key top portion of the cover portion with the thermosetting liquid resin, the uncured liquid resin (the curable resin in a liquid state in the present invention) is heated to a set temperature at which the liquid resin is cured. Poured into the mold of the shape, preferably filled, the part where the liquid resin is in contact with the mold is cured, but at the center of the mold, remove the liquid resin that kept the fluidity from the one that kept the fluidity,
Here, an uncured rubber-like elastic body that suppresses the contraction of the liquid resin during curing is filled and integrally cured, and when this rubber-like elastic body is removed, a concave shape formed of the liquid resin according to the size of the mold (especially the outer shape) is formed. In addition to finding that the product can be obtained, make the key top part of the cover member for the push button switch by this method,
If the thin movable portion and the base portion made of a rubber-like elastic body are integrally formed in the same manner as in the conventional method, a cover member for a push button switch having a key top portion having the same dimensions as the mold can be easily and stably obtained. The present invention was completed by confirming that the present invention can be applied, and that the type of curing is not limited to thermal curing, but can be applied to one- or two-component room-temperature curing type, UV curing type, infrared curing type, and the like. This is described in more detail below.

[0008]

The present invention relates to a method of manufacturing a concave molded product and a cover member for a push button switch. The concave-shaped molded body and the key top portion of the cover member for the push button switch are in a liquid state, and are preferably made of a thermosetting resin. Liquid resin such as acrylic, methacrylic, unsaturated polyester, urethane, polycarbonate, epoxy or other monomer or oligomer alone, or a compound consisting of a plurality of these materials, or by compounding them with polystyrene or diallyl phthalate,
Curing agents, coloring agents,
Examples thereof include an antioxidant, a solvent for liquefaction, a dispersant, a dispersion stabilizer, and the like.

Further, the molded concave molded body is filled with a rubber-like elastic body, or a thin movable portion, a base portion and the like made of the rubber-like elastic body are integrally formed. Examples of the rubber-like elastic material include conventionally known uncured rubbers such as butadiene-styrene, butadiene-acrylonitrile, butadiene-based copolymers such as butadiene-isobutylene, chloroprene polymers, vinyl chloride-vinyl acetate copolymers, polyurethane, and silicone rubber. Elastic bodies (including elastomers) are exemplified.

[0010] The method of manufacturing a concave molded article according to the present invention is performed by the method shown in FIG. 1, and the manufacturing of the cover member for a push button switch is performed by the method shown in FIG. FIG. 1 shows a sequential longitudinal sectional view of a manufacturing process of a concave-shaped molded body according to the present invention.
First, as shown in FIG. 1A), an uncured thermosetting resin 2 in a liquid state is poured into a concave mold 3 heated to a set temperature at which the resin is cured, by using an injection device 4. Now, fill it up. When filling, the mold does not need to be filled as long as the mold is appropriately moved or the resin is applied to wet the inner wall of the concave mold. Further, it is also possible to apply the amount of the concave shaped body measured only in advance to the inner wall, and in this case, the step of removing the resin at the center in the next step may be omitted.

Since the mold 3 is heated, the liquid resin 2 filled in the mold 3 is gradually hardened from the portion in contact with the mold toward the center as shown in FIG. 1B) and contacts the mold. Although the portion forms the film 5 that has lost fluidity, the liquid resin at the center of the mold still retains fluidity, and at this time, the resin 6 maintaining fluidity is removed by suction with the suction device 7. The space 8 is formed here.

Next, as shown in FIG. 1C),
When the space 8 is filled with an uncured rubber-like elastic body 9, and the mold 3 is closed and heated, the film 5 having lost fluidity and the rubber-like elastic body 9 are cured and integrated into FIG. 1D). Although the molded article as shown is obtained, the object of the present invention is a concave molded article, and since the resin film 5 and the rubber-like elastic body 9 are not bonded, the rubber-like elastic body can be taken out therefrom. If the desired concave shaped body 1 can be easily obtained,
This material is cured sequentially from the portion in contact with the surface of the mold 3, and is filled with a rubber-like elastic material in the central portion, and expands during curing to suppress shrinkage of the resin film 5, so that it can be thermally contracted. In addition, the thickness of the resin thickness 5 can be arbitrarily set by appropriately selecting the mold temperature and the elapsed time before suction,
In addition, there is provided an advantage that the outer shape becomes the same as that of the mold without any gap.

FIG. 2 is a sequential longitudinal sectional view of a manufacturing process of a cover member for a push button switch according to the present invention, which is a thermosetting liquid in a liquid state as shown in FIG. 2A). The filling resin 14 is used to fill the cavity 13 for molding the key top portion of the cover member for the push button switch, which is heated to a set temperature at which the resin is cured.
Since the cavity 13 is heated, the resin 12 filled in the cavity 13 is gradually cured from the portion in contact with the mold toward the center as shown in FIG. 2B) to form the resin film 15. However, when the central part of the mold still retains fluidity, the resin retaining this fluidity is removed by suction in the same manner as in FIG. 1B).

Next, as shown in FIG. 2C), a rubber-like elastic body 16 is filled in the center portion, the thin movable portion of the cover member for the push button switch, and the cavity for forming the base portion, and compression molding and injection are performed. If the key top portion, the thin movable portion, and the base portion are integrally formed by molding and transfer molding, the key top portion 17, the thin movable portion 18, and the base portion 19 as shown in FIG. Cover member 11 can be obtained.

In the above, the injection device for filling the thermosetting resin 2, 12 in the liquid state into the cavity for forming the concave mold or the key top portion is a plunger dispenser, an air dispenser, a syringe dispenser,
A roller type tubing pump, a piano touch type tubing pump, a gear pump, a snake pump, a ceramics pump, or the like may be used. As a result, the resin filled in the mold is cured from the portion in contact with the mold toward the center, and the resin that has not flown and has maintained fluidity is removed from the mold as described above. If the progress is less than 1/4 of the inner volume of the mold, the concave molded body tends to be thin, and if it is more than 1/2, the effect of preventing the resin in the liquid state due to curing from shrinking tends to be small. Therefore, it is common practice to remove the liquid resin which has maintained fluidity when the curing has progressed to 1/4 to 1/2.

In the above, the liquid resin having fluidity is removed from the concave mold or the cavity for forming the key top portion. This can be done by using a suction device such as a dropper. Good. When manufacturing a concave molded body, the timing of taking out the resin having fluidity may be set arbitrarily according to the type of liquid resin and the thickness of the concave molded body to be formed. The body thickness increases.

In this case, the uncured rubber-like elastic material is filled in the concave resin film obtained here, but when the cured rubber-like elastic material is removed, this filling is performed with a mold. It is preferable to wait until the tackiness of the surface of the liquid resin that has lost the remaining fluidity disappears, but it is preferable to carry out the process. The tackiness may be lost. This also depends on the type of liquid resin, but usually after removing the liquid resin that has maintained fluidity,
It should be 15 to 30 seconds later. In the case where the uncured rubber-like elastic body itself is rich in releasability, it is not necessary to pay particular attention to the releasability. When the rubber-like elastic body is filled with liquid rubber having a viscosity of 300 poise or less, various injection devices used for filling the resin in a liquid state can be used. This rubber-like elastic body is formed by thermosetting, and since it expands thermally, it has a function of suppressing the contraction of the liquid resin of the liquid resin around it.

The thermosetting of the resin and the rubber-like elastic body may be performed by cast molding, compression molding, injection molding, transfer molding, or the like. If the resin and the rubber-like elastic body are completely cured, they can be separated. The desired concave shaped body can be obtained, but since the rubber-like elastic body is filled after the tackiness of the resin is eliminated as necessary as described above, these are not adhered and can be easily separated. So, this can be done by separating the rubber-like elastic body and the concave-shaped molded body in order on the mold, or taking them out together and separating them separately, or by devising the mold, The body may be removed first. The concave molded body obtained in this way follows the size of the mold because the material shrinks during thermosetting is suppressed. The advantage is given that it is possible to obtain one with dimensions (outer shape).

Further, the key top portion is formed of a liquid resin,
The cover member for the push button switch in which the thin film movable portion and the base portion formed of a rubber-like elastic body are integrally formed is formed by the method described above, but in this case, the cavity for forming the key top portion is filled. In the curing of liquid resin, 30 to 80% of the liquid resin that maintains fluidity is removed with a dropper or suction device when the progress of curing is 1/4 to 1/2. In the case of obtaining a resin, it is possible to remove all the liquid resin maintaining the fluidity, and then refill a part of the resin in the same or different liquid state. However, since the filling of the rubber-like elastic body into the portion from which this liquid resin has been removed requires that the resin and the rubber-like elastic body be completely adhered to each other, the liquid resin that has lost its fluidity must be filled. It must be filled before losing tackiness, or through a tacky (adhesive) adhesive layer, or treated with a primer, to be integrated. It is preferable to carry out the reaction within 1 to 20 seconds after removing the liquid resin keeping the temperature.

The rubber-like elastic body may be formed by compression molding, injection molding, transfer molding, or the like. According to this, a key top portion made of resin and a thin movable portion made of rubber-like elastic material are used. Although a cover member for a push button switch in which the base portion is integrally molded can be obtained, since the rubber-like elastic body prevents the resin forming the key top portion from contracting due to thermosetting, the completed cover member for the push button switch is completed. The rubber-like elastic body does not cover the resin,
The advantage of being of high quality is provided. Although the above description is about a thermosetting resin, even if the resin in the liquid state is of another curing type, as the resin gradually cures from the portion in contact with the mold toward the center, For example, in the case of the ultraviolet curing type, an appropriate method such as irradiating a part in contact with the mold with ultraviolet rays may be determined experimentally.

[0021]

Next, examples of the present invention will be described. Example 1 A mold having a width (X) of 13 mm, a length (Y) of 25 mm, and a depth (T) of 6 mm was heated to 160 ° C., and 1.9 cc of an acrylic oligomer was injected with a dropper. Since the formation of an acrylic oligomer film having lost fluidity was observed on the inner surface of the mold, 0.8 cc of the acrylic oligomer maintaining the fluidity state was sucked into the center of the mold with a dropper.

After the lapse of 20 seconds, it was confirmed that the surface of the acrylic oligomer film having lost the fluidity in the mold had lost its tackiness, and then the liquid silicone rubber X32-1169 was added.
M [Shin-Etsu Chemical Co., Ltd. product name] 0.8cc was injected and compression-molded, and after 30 seconds, the integrally molded product of acrylic and silicone rubber was taken out, the acrylic and silicone rubber could be easily separated. As a result, an acrylic concave molded product (cap) was obtained. In addition, using the same mold, caps made of unsaturated polyester were made in the same manner except that this acrylic oligomer was used as an unsaturated polyester oligomer, and these sizes were compared with the mold sizes. The results were as shown in FIG. 1, all of which were exactly the same as the mold size. Note that R in the table indicates a dimensional difference (mm unit) between the mold and the cap.

[0023]

[Table 1]

Example 2 A cavity for forming a key top portion of a cover member for a push button switch having a key top portion size of 25 mm × 20 mm × 6 mm was formed.
The mixture was heated to 160 ° C, and 1.0 cc of the acrylic oligomer was injected with a dropper. After 5 seconds, the formation of an acrylic oligomer film having lost fluidity on the inner surface of the cavity was recognized. After sucking out 0.5 cc of the acrylic oligomer that maintains fluidity, drop the syringe with 0.1 cc of the acrylic oligomer sucked out again, and immediately apply liquid silicone rubber to the center, the thin movable part, and the cavities for forming the base part.・ X32-1169M
(Supra) was injected and filled in 10 cc.

Next, the mold is closed and compression-molded to form a thin movable portion and a base portion from the silicone rubber, which are integrally bonded to a key top portion made of a thermosetting resin in a liquid state. When a cover member for a push button switch was manufactured, the key top portion was not covered with silicone rubber, and the size of the key top portion was of the same high quality as that of the mold.

[0026]

The present invention relates to a method for producing a concave molded product and a cover member for a push button switch. As described above, the method for producing a concave molded product comprises a method of forming a curable resin in a liquid state into a concave shape. Poured into the mold, only the part of the resin that is in contact with the mold is cured, and when the central part is in a fluid state, the resin in the central part is removed, and after the resin remaining in the mold loses adhesiveness, it is uncured The center portion is filled with a rubber-like elastic body, the resin and the uncured rubber-like elastic body are cured, and a portion composed of the rubber-like elastic body is removed. The method of manufacturing the cover member is to cure the resin in the liquid state at the portion in contact with the cavity for forming the key top portion of the mold in the same manner as described above, and the rubber-like elasticity is applied while the liquid resin is tacky. Fill the body, shape it Make meat movable portion and the base, the resin and a thin movable part, it is characterized in that the curing integrated base unit.

Therefore, according to the present invention, since the hardening of the curable resin in the liquid state starts from the portion in contact with the outer periphery, and the hardening is performed together with the rubber-like elastic body, the molded body has the same outer shape and any shape. Can be obtained without shrinking and having the same dimensions as the mold.The cover member for the push button switch thus produced also has a key top portion covered with a rubber-like elastic body. Not
The advantage is given that it is of the same high quality as the mold dimensions.

[Brief description of the drawings]

1A to 1D are longitudinal sectional views sequentially showing the steps of manufacturing a concave molded body according to the present invention, and E) is a longitudinal sectional view of the molded body.

FIGS. 2A to 2C are longitudinal sectional views sequentially showing a manufacturing process of a cover member for a push button switch according to the present invention, and D) is a longitudinal sectional view of a cover member for a push button switch thus produced. Things.

FIGS. 3A and 3B are longitudinal sectional views sequentially showing steps of manufacturing a concave molded body according to a conventional method, and C) is a longitudinal sectional view of the molded body.

FIGS. 4A and 4B are longitudinal sectional views sequentially showing manufacturing steps of a cover member for a push button switch according to a conventional method, and FIG. 4C is a longitudinal sectional view of a cover member for a push button switch thus produced. Things.

[Explanation of Signs] 1 , 21 ... concave shaped body, 2, 12, 22, 32
... liquid resin, 3,13,23,33 ... mold (cavity),
4,14 ... injection device, 5,15 ... part where the liquid resin contacts the mold,
6: liquid resin maintaining fluidity, 7: suction device,
8 ... part where liquid resin is removed,
9, 16, 34: rubber-like elastic body, 11 , 31 : cover member for push button switch, 17, 35: key top part,
18, 36… Thin movable part, 19, 37… Base part.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int. Cl. ⁶ , DB name) H01H 11/00 B29C 33/50

Claims (2)

(57) [Claims] 1. A method according to claim 1, wherein the curable resin in a liquid state is poured into a concave mold, and only a portion of the resin in contact with the mold is cured. Removed, after the resin remaining in the mold loses the adhesiveness, fill the center with an uncured rubber-like elastic body, cure the uncured rubber-like elastic body and the resin, and configure the rubber-like elastic body. A method for producing a concave-shaped molded body, comprising: 2. A curable resin in a liquid state is poured into a cavity for forming a key top portion, and only a portion of the resin in contact with a cavity is cured. A method for manufacturing a cover member for a push button switch, wherein only a resin is removed, and an uncured rubber-like elastic body is filled in a cavity for forming the central portion, a thin movable portion, and a base portion, and integrally molded.