JPH0952252A - Resin molded product for encapsulating electrodes and manufacturing method thereof - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve the connecting strength at the boundary between a resin molding and a resin formed molding. SOLUTION: In the resin molding for sealing an electrode by the resin molding 2 and a resin formed molding 4 by forming the molding 4 in the state that the electrode is exposed on the surface of the molding 2, the molding 2 is brought into close contact with the molding 4 and coupled to the molding 4 by a fibrous member 3 existing on a boundary. Since the connecting strength of the molding 2 to the molding 4 is improved by the anchoring effect of the member 3, a microcrack is prevented to prevent the short-circuit.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin molded product used for electric / electronic parts and sealing an electrode, and a method for manufacturing the same.

[0002]

2. Description of the Related Art As a means for holding electrodes and facilitating connection with other parts and preventing a short circuit, a structure in which an electrode is sandwiched between a pair of resin molded products fixed by bolts or the like is known. ing. This structure is easy to disassemble, and is used when it is necessary to disassemble a household outlet or plug.

On the other hand, when disassembling is unnecessary, a structure in which a part of the electrode is embedded in a resin molded product is often used. This structure can be easily formed by holding the electrode in a mold and forming a resin molded product by injection molding or the like. By the way, when embedding an electrode in a resin molded product, it may be difficult to embed it in one molding depending on the shape of the electrode or the shape of the resin molded product. For example, in the electronic component as shown in FIG. 6, the electrode 1a is exposed on the inner peripheral surface of the frame body 40, but the exposed area of the electrode 1a needs to be as small as possible. In order to form such an electronic component, the three electrodes 1a, 1b, 1c shown in FIG. 4 are placed in a mold, and a primary resin molded product 2 as shown in FIG. 5 is formed by injection molding. , The electrodes 1a, 1b, 1c are held and fixed so as not to move. Next, the primary resin molded product 2 to which the electrodes 1a, 1b, 1c are fixed is placed in another mold, and the secondary resin molded product 4 is formed as shown in FIG. 6 to complete the frame 40. .

[0004]

However, by forming the secondary resin molded product 4 as described above, the primary resin molded product 2 is obtained.
In the resin molded product that is joined to the resin molded product, the interface between the primary resin molded product and the secondary resin molded product is the portion having the smallest strength. In other words, when forming a secondary resin molded product, the molten resin flowing in the cavity comes into contact with the mold, the primary resin molded product and the electrode surface, and the thermal conductivity of each is different, so the cooling rate of the secondary resin molded product is They are partially different, and the surface temperature of the primary resin molded product also varies. Therefore, it is considered that thermal stress is generated in the secondary resin molded product, and the bonding strength at the interface with the primary resin molded product becomes small.

Therefore, attempts have been made to solve the above problems by ensuring the adhesion between the primary resin molded product and the secondary resin molded product by controlling the mold temperature and injection pressure during molding. However, the current situation is that there is a large variation and a complete solution has not been completed. Further, since the mold structure becomes complicated, there is a problem that the man-hours for designing and manufacturing the mold become large.

When such a resin molded product is used under severe conditions, stress is concentrated on the interface between the primary resin molded product and the secondary resin molded product due to heat change, etc., and microcracks are generated at the interface. It may occur. When microcracks are generated in this way, water or the like may enter the inside of the resin molded product through the microcracks due to the capillary phenomenon, and a short circuit may occur between the electrodes.

Therefore, conventionally, the gap between the electrodes is made sufficiently large so that a short circuit does not occur even if water or the like should enter. However, by doing so, the shape of the resin molded product becomes large. There was a problem that it ended up. The present invention has been made in view of such circumstances, and an object thereof is to improve the bonding strength at the interface between the primary resin molded product and the secondary resin molded product.

[0008]

The features of the resin molded product for encapsulating the electrode of the present invention which solves the above-mentioned problems are that a secondary resin molded product is formed with the electrode exposed on the surface of the primary resin molded product. Then, in the resin molded product in which the electrode is sealed with the primary resin molded product and the secondary resin molded product by joining with the primary resin molded product, the primary resin molded product and the secondary resin molded product are in close contact with each other and exist at the interface. It is configured to be connected to each other by a fibrous member.

The manufacturing method of the present invention for producing this resin molded product is characterized in that the first step of forming the primary resin molded product and a part of the fibrous member embedded in the surface of the primary resin molded product The second step of projecting from the surface of the primary resin molded product, and placing the electrode on the surface of the primary resin molded product in a mold and supplying molten resin to the electrode and the fibrous structure protruding And a third step of forming a secondary resin molded product that covers the member and is joined to the primary resin molded product.

[0010]

BEST MODE FOR CARRYING OUT THE INVENTION The material of the primary resin molded product and the secondary resin molded product is not particularly limited as long as it is a resin having a high electric insulation property, and polyamide (PA), polybutylene terephthalate (PBT), polyphenylene sulfide ( PPS), polycarbonate (PC), polypropylene (PP), polyethylene terephthalate (PET), etc. can be used.

As the fibrous member, organic short fibers, short fibers of various inorganic oxides or metals, whiskers and the like can be used, but it is desirable to select a material having high electric insulation. The length of this fibrous member is preferably 1 μm or more, and if it is shorter than this, the reinforcing effect is reduced. To make a state in which a part of this fibrous member is embedded in the surface of the primary resin molded product and the remaining part protrudes from the surface of the primary resin molded product, for example, the surface of the primary resin molded product is thinly removed and There is a method of exposing the fibrous member included in. For example, if a primary resin molded article is formed from a resin material containing glass fibers and heated at a temperature not lower than the melting point of the resin of the primary resin molded article and lower than the melting point of the glass fibers to carbonize or decompose only the resin to remove, The exposed glass fibers can be exposed and partly buried, and the remaining part can be projected.

When a primary resin molded product is formed from a resin containing a fibrous member, the fibrous member is oriented along the mold surface on the surface along the mold surface. Therefore, no matter how much resin is removed in that portion, the number of fibrous members protruding from the surface becomes small, and the orientation is disturbed from the surface of the primary resin molded product by about 1
It is desirable to remove the resin to a depth of 0 μm. It is also possible to collide the fibrous member with the surface of the primary resin molded product so that a part of the fibrous member is embedded and the rest is exposed. In this case, it is preferable to heat the surface of the primary resin molded product to soften it. It is also a preferable method to heat the fibrous member to a temperature equal to or higher than the softening temperature of the primary resin molded product and then to cause the collision. According to this method, there is no loss of resin and the yield is improved as compared with the method of removing the resin described above.

In the method for producing a resin molded product for encapsulating an electrode according to the present invention, a part of the fibrous member is embedded as described above on the surface of the primary resin molded product to which the secondary resin molded product is joined. The rest is exposed and protrudes from the surface. Therefore, since the protruding fibrous member is embedded in the secondary resin molded product formed on the surface thereof, the primary resin molded product and the secondary resin molded product are in a state of being connected by the fibrous member.

In the resin molded product for encapsulating the electrode of the present invention, the primary resin molded product and the secondary resin molded product are separated by the fibrous member existing at the interface between the primary resin molded product and the secondary resin molded product. They are connected and the anchoring effect greatly improves the joint strength. Therefore, even if stress is concentrated on the interface between the primary resin molded product and the secondary resin molded product when used under severe conditions, generation of microcracks is prevented.

[0015]

EXAMPLES The present invention will be described in more detail below with reference to examples. This embodiment relates to the electronic component shown in FIGS. (Example 1) (1) First step Three electrodes 1a, 1b, 1c made of copper were placed in a predetermined mold (not shown) so as to be at the relative positions in FIG.
A primary resin molded product 2 shown in FIG. 5 was manufactured by injection molding using a PPS resin containing 30% by volume of a glass fiber 3 of 00 μm. This primary resin molded product 2 has a cylindrical electrode portion 2
0 and a pair of leg portions 21 extending from the electrode portion 20,
Each of the three electrodes 1a, 1b, 1c has an electrode portion 2 at the tip.
It is exposed to 0. The other end of the center electrode 1b is embedded in the electrode portion 20 and exposed on the back side of the electrode portion 20. The other ends of the two both-side electrodes 1a and 1c are embedded in the leg portions 21, respectively, and the tips thereof are of the leg portions 21. It is exposed on the surface. As a result, the central electrode 1b and the side electrodes 1a and 1c are held and fixed to the primary resin molded product 2 so as not to move. (2) Second Step Next, as shown in FIG. 1, the surfaces of the pair of leg portions 21 on which the other ends of the both-side electrodes 1a and 1c of the primary resin molded product 2 are exposed are heated in the atmosphere. The heating temperature is higher than the melting point of the resin of the primary resin molded product 2 and equal to or lower than the melting point of the glass fiber 3, and is in the range of about 250 ° C to about 700 ° C. As a result, the surface resin of the leg portion 21 is carbonized, and then the carbide is removed by chemical cleaning or air blow to clean the surface of the leg portion 21. As a result, the glass fiber 3 is exposed on the surface of the leg portion 21, a part of the glass fiber 3 is embedded in the leg portion 21, and the remaining portion is exposed and protrudes. Since the glass fibers 3 are oriented along the surface of the leg portion 21, the amount of resin removed is set to a depth of 10 μm from the surface to a position where the orientation is disturbed, in order to increase the amount of protrusion from the surface. did.

Instead of heating in the atmosphere, heating may be performed in an atmosphere of an inert gas such as nitrogen gas or in vacuum. In this case, the surface resin of the leg portion 21 is decomposed without being carbonized. If the decomposition products are gaseous, there is no need to remove them,
If decomposition products remain, they may be removed by chemical cleaning or air blow. (3) Third step The primary resin molded product 2 with the glass fibers 3 protruding from the surface of the leg 21 is placed in a predetermined mold not shown, and the same PPS resin containing glass fiber 3 as the primary resin molded product 2 is placed. A secondary resin molded product 4 shown in FIG. 6 is formed by injection molding using, to form a resin molded product that seals the electrodes of this embodiment.

The secondary resin molded product 4 is formed in a substantially U shape having a part of the leg portion 21 of the primary resin molded product 2, and the resin molded product has a frame-shaped portion 40. And a pair of both-side electrodes 1a, 1c
Also, the tip of the central electrode 1b is slightly exposed on the inner peripheral surface of the frame-shaped portion 40. In this resin molded product, since the primary resin molded product 2 and the secondary resin molded product 4 are connected to each other by the glass fiber 3 in the leg portion 21 of the primary resin molded product 2, the bonding strength of the part is increased by the anchoring effect. It has improved significantly. (Example 2) This example is the same as Example 1 except for the second step.
That is, in the second step, as shown in FIG. 2, the glass fibers 5 heated to about 250 ° C. to about 700 ° C. are blown against the surface of the leg portion 21 of the primary resin molded product 2 by shot blast or the like to collide them. The surface of the leg portion 21 is melted by the heat of the colliding glass fiber 5, and a part of the glass fiber 5 is embedded in the leg portion 21.

Instead of heating the glass fiber 5, the glass fiber 5 may be sprayed with the surface of the leg portion 21 of the primary resin molded product 2 being heated and softened, or the glass fiber 5 and the leg. The glass fiber 5 may be sprayed with both surfaces of the part 21 heated. Therefore, by performing the third step in the same manner as in Example 1, the resin molded article manufactured in this Example has the leg portion 2 of the primary resin molded article 2 as in Example 1.
In 1, the primary resin molded product 2 and the secondary resin molded product 4 are connected to each other by the glass fiber 5, so that the bonding strength at that portion is remarkably improved by the anchoring effect.

In this embodiment, since the resin of the primary resin molded product 2 does not have a loss as compared with the first embodiment, the yield is improved as compared with the first embodiment. (Example 3) This example is the same as Example 1 except for the second step. That is, in the second step, as shown in FIG. 3, the PPS resin powder 6 (particle size 100 μm) is formed on the surface of the leg 21 of the primary resin molded product 2.
m or less) is attached.

When the primary resin molded product 2 to which the resin powder 6 is attached is placed in the mold and the third step is carried out in the same manner as in Example 1, the resin powder 6 has an extremely large surface area, so that the secondary resin molded product is obtained. The resin injected at the time of forming 4 melts very easily, and the primary resin molded product 2 and the secondary resin molded product 4 are welded by the molten resin powder 6. Further, since the resin powder 6 is easily melted, variations in the temperature distribution on the surface of the primary resin molded product 2 are eliminated when the secondary resin molded product 4 is formed, and the primary resin molded product 2 and the secondary resin molded product 4
The joint strength at the interface with and is improved.

[0021]

That is, according to the resin molded product for sealing the electrode of the present invention, since the bonding strength at the interface between the primary resin molded product and the secondary resin molded product is improved, it can be used under severe conditions. In such a case, even if stress concentrates on the interface, generation of microcracks is prevented, and reliability is improved. Therefore, even if the distance between the electrodes is reduced, there is almost no risk of a short circuit, so that the shape of the resin molded product can be reduced.

Further, according to the method for producing a resin molded product for encapsulating an electrode of the present invention, the primary resin molded product and the secondary resin molded product can be easily and reliably connected by the fibrous member. Therefore, the bonding strength between the primary resin molded product and the secondary resin molded product is improved without considering the temperature distribution and pressure distribution in the mold, so that the mold structure is simple and simple, and mold design and mold manufacturing can be performed. The man-hour required is reduced.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of a second step in one example of the present invention.

FIG. 2 is an explanatory diagram of a second step in the second embodiment of the present invention.

FIG. 3 is an explanatory diagram of a second step in the third embodiment of the present invention.

FIG. 4 is a perspective view of an electrode used in one embodiment of the present invention.

FIG. 5 is a perspective view of a primary resin molded product formed in one embodiment of the present invention.

FIG. 6 is a perspective view of a resin molded product formed in one embodiment of the present invention.

[Explanation of symbols]

1a, 1b, 1c: Electrode 2: Primary resin molded product 3: Glass fiber 4: Secondary resin molded product
5: Glass fiber

Claims (2)

[Claims] 1. A secondary resin molded product is formed in a state where an electrode is exposed on the surface of the primary resin molded product, and the secondary resin molded product is bonded to the primary resin molded product, and the primary resin molded product and the secondary resin molded product are joined together. In a resin molded product in which the electrode is sealed, the primary resin molded product and the secondary resin molded product are in close contact with each other and are connected to each other by a fibrous member existing at the interface, which seals the electrode. Molded resin products. 2. A first step for forming a primary resin molded article, and a second step for making a state in which a part of a fibrous member is embedded in the surface of the primary resin molded article and the rest is projected from the surface of the primary resin molded article. A second resin bonded to the primary resin molded product by covering the electrode and the protruding fibrous member by placing the electrode on the surface of the primary resin molded product in a mold and supplying a molten resin. A method for producing a resin molded product for encapsulating an electrode, comprising: a third step of forming a next resin molded product.