JPH0240206A - Device for defoaming resin - Google Patents

Abstract

PURPOSE:To surely defoam a high-viscosity resin by placing a vessel contg. a resin to be defoamed in a hermetically sealable defoaming vessel main body, depressurizing the main body by an evacuating means, and providing a foam breaking means to be brought into contact with the film surface of the bubbles generated in the resin. CONSTITUTION:The foam breaking device 11 is fixed to the vessel 9 contg. a resin 8, the vessel 9 is set in the defoaming vessel main body 1, a lid 3 for the main body 1 is closed, and the main body 1 is hermetically sealed. A vacuum pump 7 is then operated to evacuate the main body 1, and air bubbles are generated in the resin 8. The tip 12 of the foam breaking device 11 is brought into contact with the film surface of the bubbles, hence the film surface is broken, and the air in the bubble is discharged.

Description

[Detailed description of the invention] [Object of the invention] (Industrial application field) The present invention is used to remove air mixed in resin used as a material for molding electronic circuits and for rebotting. The present invention relates to a defoaming device.

(Prior Art) In order to improve the reliability of electronic carriers, it is important to make them resistant to shock and vibration, and to eliminate causes of moisture, dust, and corrosion. To this end, repotting has conventionally been carried out by molding the entire electronic circuit with a thermosetting resin.

Air is often mixed into the resin used for molding and potting during the resin manufacturing process, that is, during the mixing process of the main resin and the curing agent or filler. If such resin with air mixed in is used as it is in molds or bottigs, the air mixed in the resin will expand and become bubbles due to the heating of the resin for curing or the heat generated by the curing reaction. The resin hardens while containing air bubbles, making molding and potting ineffective. Therefore, if bubbles were generated during molding or potting, the product could not be a genuine product and had to be discarded as a defective product.

Therefore, conventionally, a defoaming device as shown in Fig. 2 was used to
Since the air contained in the resin is removed in advance before the resin is used for molding or potting, a conventional defoaming device will first be explained.

In Figure 2, 1 indicates the defoaming tank main body, which is the defoaming tank 2.
and a defoaming tank lid 3, both of which are engaged with each other so that they can be opened and closed with a pin 4, and are closed with a stopper 5. In the closed state, the interior of the degassing tank main body 1 is constructed to be airtight. Reference numeral 6 denotes an exhaust pipe connected to the defoaming tank 2, and the other end is connected to a vacuum pump 7 for exhaust. In the defoaming tank 2, there is placed a container 9 which is open at the top and contains a resin 8 for defoaming.

Next, the defoaming method will be explained. First, a container 9 containing the resin 8 to be degassed is placed in the tank 2, and the lid 3 is closed. Next, the vacuum pump 7 is operated to evacuate the inside of the defoaming tank body 1 and lower the pressure inside the defoaming tank main body 1. In this way, the third
As shown in the figure, the air mixed in the resin 8 bubbles (
10), and finally the load due to the pressure difference between the inside and outside of the bubble overcomes the surface tension of the bubble, causing the bubble to burst and the air inside to flow out into the defoaming tank main body 1. Since this is discharged to the outside of the defoaming tank main body 1 through the exhaust pipe 6, the air mixed in the resin 8 is removed.

Therefore, this defoamed resin is used for molding and potting.

By the way, defoaming of resin using the above-mentioned conventional defoaming device is
It depends on the load due to the pressure difference between the inside and outside of the bubbles generated by bringing the inside of the defoaming tank into a low pressure state to overcome the surface tension of the bubbles. Therefore, it has been difficult to apply it to high viscosity resins.

In other words, a high viscosity resin has a strong surface tension, and the surface tension of the bubble is greater than the pressure difference between the inside and outside of the bubble, so even if the bubble reaches the opening of the container 9 as shown in FIG.
There was a problem that the surface could not be broken, and as a result, the air mixed in the resin 8 could not be discharged, or the air could only be defoamed incompletely.

(Problems to be Solved by the Invention) Conventional resin defoaming devices have a drawback in that they cannot adequately defoam resins with high surface tension and high viscosity.

SUMMARY OF THE INVENTION The present invention has been made with the object of solving the conventional drawbacks and providing a defoaming device capable of defoaming even high viscosity resins.

[Structure of the Invention] (Means for Solving the Problems) In order to achieve the above-mentioned problems, the resin defoaming device according to the present invention includes a sealable defoaming tank main body and a defoaming tank connected to the defoaming tank main body. a supply/exhaust means, a container provided in the degassing tank body and containing the resin to be defoamed, and a container provided in or near the container itself, and reducing the pressure inside the degassing tank body by the exhaust device. The invention is characterized by comprising a bubble breaking means that contacts the membrane surface of the resin bubbles generated by the process.

(Function) According to the above means, since the membrane surface of the bubbles generated during defoaming comes into contact with the bubble breaking means, even the membrane surface of the bubbles with a strong surface tension can be easily broken and the air can be discharged. .

(Example) An example of the present invention will be described in detail below with reference to FIG. In this figure, parts that are the same as those in FIG. 2 are given the same reference numerals, so a description of those parts will be omitted.

FIG. 1 is a longitudinal sectional view showing an embodiment of a resin defoaming device according to the present invention. In this figure, reference numeral 11 denotes a bubble breaker, which has a number of protrusions 12 with sharp edges and triangular cross-sections, and is attached to the opening of the resin container 8 with a fitting 13 toward the resin 8 side. It is being In addition, when attaching the bubble breaker 11 to the resin container 8, in order to improve the circulation of air between the inside of the defoaming tank 2 and the inside of the container 9, the fitting 13 should be made into a beam shape or a lid shape. A large number of through holes 14 are provided.

Further, an air supply pipe 15 is connected to the defoaming tank 2, and a valve 16 is provided on the air supply pipe 15 to supply or stop air into the defoaming tank 2, or to adjust the amount of air to be supplied. It is configured so that you can do it.

The operation of the resin defoaming device according to the present invention configured as described above will be explained below.

First, a container 9 containing resin 8 and a bubble breaker 11 attached thereto is placed in the defoaming tank main body 1, and the defoaming tank lid 3 is closed to make the container airtight. Valve 16 is also closed. Next, the vacuum pump 7 is operated to evacuate the inside of the degassing tank body 1. Defoaming tank body 1
When the internal pressure decreases, the air mixed in the resin 8 becomes bubbles, as in the past. The height of the top surface of the resin bubble varies depending on the pressure difference between the inside and outside of the bubble, and as the pressure inside the defoaming tank body 1 decreases, the height of the top surface of the bubble increases as shown in FIG. Rise. Therefore, the surface of the bubble, that is, the membrane surface, contacts the tip 12 of the bubble breaker 11 and breaks the membrane surface.
The air inside it is expelled. Furthermore, by opening and closing the valve 16, the air pressure inside the defoaming tank body 1 can be changed rapidly, and when the valve 16 is throttled, the upper surface of the bubbles rises rapidly and collides with the tip of the bubble breaker 11. , can break the membrane surface more effectively.

Even when a film surface with strong surface tension is formed when defoaming a highly viscous resin, the device of the present invention is capable of degassing the film surface of bubbles by not only the pressure difference but also the action of an external force. can be definitely broken.

Note that the present invention is not limited to the embodiment shown in FIG.
Various modifications are possible. For example, the bubble breaker 11 is
It may be fixed to the degassing tank 2, its lid 3, etc. so as to be located roughly in the vicinity of the container. Further, the tip of the bubble breaker 11 may be pin-shaped, and these may be arranged in a row or a grid. Furthermore, the bubble breaker 11 is configured to be movable vertically or horizontally from outside the defoaming tank main body 1 via a drive means, and by frequently bringing the bubbles into contact with the film surface, the bubbles are further broken. It becomes easy and reliable.

Further, the intake pipe 15 may be provided so as to branch from the exhaust pipe 6.

[Effects of the Invention] As detailed above, according to the present invention, even if the resin is of high viscosity and the surface tension of the bubbles generated in the defoaming tank is strong, the defoaming can be reliably performed. Able to produce high quality degassed resin.

Therefore, if the resin defoamed using the device of the present invention is used for molding or potting electronic circuits, there is no risk of air bubbles being contained in the mold, botti, or puffer, reducing production loss of electronic circuits, etc. , product reliability can be improved.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view showing an embodiment of the resin defoaming device according to the present invention, FIG. 2 is a longitudinal sectional view showing a conventional defoaming device, and FIG. FIG. 1... Defoaming tank main body 6... Exhaust pipe 9... Container 11... Defoaming device 15... Air supply pipe 1, Degassing 7ta 2a Zero I; To 1 and 2 birds 1-? L.S., R.S., Patent Attorney, O.K., Figure 1

Claims (1)

[Claims] A sealable defoaming tank main body, a supply/exhaust means connected to the defoaming tank main body, a container provided in the defoaming tank main body and containing the resin to be defoamed, and the container itself or the vicinity of the container. 1. A resin defoaming device, comprising: a bubble-breaking means that is installed in the degassing tank body and comes into contact with a film surface of resin bubbles generated by reducing the pressure inside the defoaming tank main body by the exhaust means.