JPS60169122A - Method of coating resin of electronic part - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a coating method for efficiently impregnating electronic parts and coating them with resin for exterior packaging.

In recent years, as electronic devices have become smaller and lighter, there has been a strong demand for the electronic components used in these devices to be lighter, thinner, and smaller.

In addition, low cost is also desired.

Then, by simultaneously performing part hardening, a
This paper proposes a coating method that simplifies the steps necessary for the coating process and deposits a uniform coating film.

Electronic parts are generally painted in cases.

Resin mold molds, resin immersion molds, etc. are used, but although the two-dimensional precision of cased bases and mold features is good, the shape is dog-like. On the other hand, resin immersion’! Although the dimensional accuracy of Ra is slightly inferior, this method is often used because it is small and relatively easy to produce a III-mount.

In general, the method using Rei II-IIt-kai is carried out using two types of resin for the two impregnation layers and the exterior layer, and liquid resin is mainly used for the impregnation layer, and liquid resin or powder resin is used for the exterior resin. . 'Conventionally, when using a liquid resin for outer coating, first, the liquid resin is immersed in a resin at normal pressure or in a vacuum, and then cured by heating, etc., and then applied.

Liquid resin for the exterior was applied in a similar manner.

In general, exterior resins are treated with a thixotropic agent such as Erosil (trade name) to prevent the formation of wood 11, so they have a high viscosity and adhere thickly to flat areas, causing no edges. The parts tended to adhere relatively thinly. In addition, when it is pulled up from inside the exterior resin, resin sag (commonly referred to as a horn shape) occurs at the tip, similar to the tip of a chess piece, and this sag forms a shape that increases the height dimension. Commonly used methods include the fluidized immersion method, in which the electronic components are heated and immersed in powdered resin after curing, and the electrostatic coating method, in which the powdered resin is charged and attached to grounded electronic components using Coulomb force. used.

These methods provide a uniform coating thickness.

The coating film tends to be thicker than necessary, and the size of the electronic component becomes large. Furthermore, when using liquid resin for the exterior resin, apply a mold release agent such as silicone or fan type to parts such as lead wires where you do not want the resin to adhere in advance, and when dipping into the resin, Methods are used to prevent this from adhering, but when powdered resin is used as the exterior resin, C.

This is ineffective and means to remove it later using a mechanical method is used.

According to the present invention, it is possible to obtain a small and lightweight electronic component that eliminates the drawbacks of coating methods using liquid and powder resins, and it is also possible to shorten the coating process.

To explain the method in more detail, if necessary, apply a mold release agent in advance to the parts of the lead wires of the electronic components where you do not want the resin to adhere, and then immerse the electronic components in liquid resin to impregnate them, and then immediately after pulling them out. The resin is immersed in a powder resin, the adhesive of the liquid resin causes the powder resin to adhere to the entire surface to which the liquid resin is attached, and then the liquid resin and the powder resin are hardened by heating or the like.

According to this method.

(1) The coating process can be shortened, and at the same time, only one heating is required for curing, and less electricity is required for heating, making it more economical.

(2) Powder resin is applied only to the areas where liquid resin is applied, and a uniform and appropriate coating film is obtained without any resin dripping. Powder resin does not adhere. Therefore, the effort of removing unnecessary resin can be saved.

In order to compare the resin coating process, a block diagram is shown below.

(-) Conventional process Imu$ul using liquid resin for the exterior
-1il-Rakusho1-i-i*ii”iil-1aqij
(b) Conventional process using powder resin for the exterior 1) 1-1
1-I Unnecessary resin removal 1-1-1 Flower 1 (C) Process vehicle power of the present invention ← l-ill-i ← Hayato Q (-i ←-1 In other words, the curing process after impregnation and the preheating of electronic components before immersion into the powder are no longer required, and the process of removing unnecessary resin attached to the lead wires is also eliminated, shortening the process. , it can be simplified.

The diagram will be explained.

FIG. 1 shows a case where the exterior is made of liquid resin, and the element 1 shown in FIG. 1(a) is placed with the lead wire 2 above the resin liquid.

When it is pulled up, the resin inevitably heats and solidifies with the head 3 hanging down as shown in Figure (b), so the height tends to increase. The figure (C) shows a cross section taken along line A-A. 1 is an element, and 4 is a coating resin. Sex part 5
The coating film tends to become thinner.

FIG. 2(a) shows a case where the outer coating is made of powdered resin, and as shown in the figure, the resin 6 is thickly adhered to the immersion level position Bt including the lead wire.

If the resin adheres to the base of the lead wire where you do not want it, please refer to 1.
Must be removed by mechanical means.

In this case, it is difficult to remove even by mechanical methods unless a mold release agent is applied in advance. (1+) shows a 0-0 cross section, and the resin tends to stick thickly.

Figure 3 shows the resin coating method according to the present invention.
The element 1 in Figure 4 is impregnated with liquid resin 7 (Figure BJ), and the element 1 is further soaked in powder resin 8 and pulled up (Figure C1).
Thereafter, this was heated and cured all at once, and a uniform coating film 9 was formed (Fig. 4).

If a mold release agent is applied to the lead wire in advance, the resin will not adhere to the base of the lead wire where it is not desired.

In the above, explanation has been given of impregnating an electronic component with a liquid resin and then covering it with a powder resin. However, the present invention can also be applied in the case of a resin coating in which the electronic component is not impregnated and is only covered with a powder resin. By pre-immersing the liquid resin in advance and then immediately soaking it into the powdered resin, it is possible to avoid the conventional method of soaking the powdered resin into the powdered resin.
This makes it possible to omit preheating of the sub-components and to provide a uniform coating, which is a feature of the present invention.

In this case, a low viscosity thermosetting resin is used as the liquid resin.

An example of a film capacitor will be shown below as an example of the present invention.

[Example 1] A polyethylene terephthalate film capacitor was immersed in an epoxy resin with a viscosity of 200 cpl and a curing temperature of 110°C, and immediately after being pulled up, air was sent from the bottom surface to form fluid streaks into the epoxy powder with a curing temperature of 110°C. Immerse it in a resin bath and take it out.

It was placed in an open oven at 120° C. and cured by heating for 2 hours.

The resulting capacitor is uniformly coated.

In addition, there was no difference in performance compared to the conventional method.

In addition, as a means of curing, although curing was performed by heating in the example, the same effect can be obtained by curing using UV (ultraviolet light), BB (electron beam), or the like.

Confirmed.

[Example 2] A polyethylene terephthalate film capacitor was immersed in a liquid polyester resin with a reaction initiation temperature of 80°C, and after being impregnated and pulled up, the reaction initiation temperature was 1 in the same manner as in Example 1.
It was immersed in polyester powder resin at 0.5°C, taken out, and placed in an oven whose temperature settings could be controlled by a program.

First step: 90℃ for 1 hour, second step: 120℃
It was heated and cured for 2 hours. In the first step, the liquid polyester resin is cured, and in the second step, the powdered polyester resin is cured, and the resulting capacitor is covered with a uniform coating film, and the performance is different from that of the conventional method. There was no.

The liquid resin is thermosetting epoxy resin.

A polyester resin or the like is preferred, but since it has a mutual effect with the powder resin, any suitable resin can be selected.

Further, as the powder resin, epoxy resin is mainly used for electronic parts, but it is not limited to this, and a wide range of suitable materials can be used.

Example 1 is a case where the curing temperature of the liquid thermosetting resin and the curing temperature of the powder resin are the same, and Example 2 is a case where the curing temperature of the liquid thermosetting resin is lower.

If the curing temperature of the liquid resin is higher than that of the powder resin, the powder resin will harden first when the tree 1 is cured, and then the inner liquid resin will harden, causing the surface of the cured product to shrink due to curing shrinkage, etc. My occurrence.

Residual strain occurs inside the element, which is undesirable.

According to the present invention, the painting process can be streamlined, so
In addition to being economical and making it possible to reduce manufacturing costs through mass production, it also allows for capacitors with uniform coating without resin sag, which is a method that meets the demands for miniaturization. be. 11 Akira talked about capacitors, but it can also be applied to other electronic parts, and overall, I think it is a meaningful invention that will make a great contribution.

This drawing is a simple a8i! Figure 1 (1) ~ (Represents explanation about liquid resin exterior method @
Figure 2 (A), (Chrysanthemum is an explanatory diagram showing the exterior resin adhesion state 1 due to powder self-packing, Figure 3 (m) - (Chrysanthemum is 9) is an explanatory diagram showing the state of impregnation and exterior coating according to the present invention It is.

1......Electronic component element (body) 2...
...Lead wire 3...Dragging resin part 4...Resin coated part S...
・・・Thin edge part of coating 6 ・・・・・・Powder resin liquid part 7 ・・・・・・Painted liquid edible resin 8 ・・・・・・・・・Powder resin 9 deposited on the liquid resin......The resin deposited by the method according to the present invention [I! Coating film %l area (θ, n(b・〉 almost 30 (, L2(b)(c)cdn procedure amendment issue) February 7, 1985 Patent Office Commissioner Shiga Manabudon■, minor incident display Patent Application No. 59-23018 2, Name of the invention: Method for coating electronic parts with resin 3, Person making the amendment Relationship to the case Patent applicant address: 1-3-18 Hiroo, Shibuya-ku, Tokyo Name: Ninosei Electric Co., Ltd. 4: Each column contains a detailed description of the agent.

6. Contents of correction (1) The statement of the claims shall be amended as follows.

[In the method of coating electronic parts with resin, the powder resin is deposited on the liquid resin by immersing it in a thermosetting powder resin with a low viscosity and curing temperature, and then the liquid resin is coated by heating etc. A method for coating electronic components with resin, characterized by curing a resin and a powder resin at the same time. (2) "Thermosetting powder resin" in the first line from the bottom of page 1 of the specification is corrected to "thermosetting powder resin."

(3) “Thermosetting powder resin” on page 1, line 8 of the specification is “
Corrected to ``thermosetting powder resin''.

that's all

Claims (1)

[Claims] In a method of coating electronic parts with resin, after immersing the electronic parts in a low-viscosity thermosetting liquid resin, a powder resin is immediately applied on the liquid resin. A method for coating electronic parts with resin, which comprises curing the liquid resin and powder resin at once by heating or the like.