JP2003165114A - Resin varnish impregnation equipment in prepreg production - Google Patents

Abstract

(57) Abstract: A prepreg having a good appearance is produced by preventing bubbles generated in a resin varnish of an impregnation tank from adhering to a sheet-like fiber base material. A preparation tank (2) for a resin varnish (1), an impregnation tank (3),
Receiving tank 4 for resin varnish overflowing from impregnation tank 3
And the bottom opening 3 of the impregnation tank with the resin varnish 1 of the preparation tank 2
1 to the impregnation tank 3. A pipe is provided so that the resin varnish overflowed from the impregnation tank 3 to the receiving tank 4 is returned to the preparation tank 2. In such a configuration, the impregnation tank 3 includes the foam removing member 5. The foam removing member 5 is installed on the liquid surface of the resin varnish between a position 6 where the sheet-like fiber base material 11 is drawn into the resin varnish and a position directly above the bottom opening 31 of the impregnation tank 3.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a resin varnish impregnating apparatus for manufacturing prepreg. The manufactured prepreg is a material for forming an insulating layer or the like of a printed wiring board.

[0002]

2. Description of the Related Art The resin varnish impregnating apparatus generally has a structure as shown in FIG. Preparation tank 2 for resin varnish 1
The resin varnish 1 of the preparation tank 2 is supplied to the impregnation tank 3 through the bottom opening 31 of the impregnation tank, and the impregnation tank 3 is provided. A pipe is provided so that the resin varnish overflowed from the container to the receiving tank 4 is returned to the preparation tank 2. The tip of the reflux pipe 7 is submerged in the resin varnish 1 in the preparation tank 2. The continuous sheet-shaped fibrous base material 11 that is sequentially transferred is drawn into the resin varnish of the impregnation tank 2 and, after a predetermined impregnation operation, is introduced into a drying furnace and becomes a prepreg through a heating and drying step. In the piping system of the impregnating device, the resin varnish is circulated, and the resin varnish adjusted to a predetermined concentration in the preparation tank 2 is supplied to the impregnation tank 2 so that the resin varnish in the impregnation tank 2 can be replaced sequentially or at predetermined intervals. In consideration of this, the characteristics of the resin varnish with which the sheet-shaped fiber base material 11 is impregnated are homogenized and stabilized.

[0003]

However, in the above resin varnish impregnation apparatus, foaming of the resin varnish occurs when the resin varnish is supplied to the impregnation tank 2. When the foam adheres to the sheet-shaped fiber base material, the manufactured prepreg has a phenomenon of "repellency" in which a pinhole is generated in the foam adhesion portion or the resin varnish is not impregnated in the foam adhesion portion. There's a problem.

The problem to be solved by the present invention is to prevent the bubbles generated in the resin varnish in the impregnation tank from adhering to the sheet-shaped fiber base material, and to produce a prepreg having a good appearance. There is provided a resin varnish impregnating apparatus for manufacturing a prepreg for that purpose.

[0005]

In order to solve the above-mentioned problems, a resin varnish impregnating apparatus for producing a prepreg according to the present invention is a resin varnish impregnating apparatus described in the above-mentioned prior art, and has the following novel structure. Is added. That is, although the impregnation tank is equipped with a foam removing member, this foam removing member is installed on the liquid surface of the resin varnish, and its installation position is the drawing position of the sheet-shaped fiber base material into the resin varnish and the impregnation tank. It is characterized in that it is between the position directly above the bottom opening of the.

The foaming of the resin varnish in the impregnation tank mainly occurs when the resin varnish is supplied to the impregnation tank through the bottom opening of the impregnation tank. Since the bubbles float almost directly above the bottom opening and float on the liquid surface of the resin varnish, by installing the foam removing member at the above position, the bubbles floating on the liquid surface of the resin varnish are drawn into the sheet-shaped fiber base material. It is intended to prevent the bubbles from adhering to the sheet-like fiber base material by suppressing the movement to the position.

The impregnation tank preferably has a shallow bottom in the range from the bottom opening to just below the installation of the foam removing member. By doing so, the bubbles mixed from the bottom opening can be floated to the liquid surface more quickly, and the bubbles can be prevented from approaching the retracted position while floating in the resin varnish.

Further, the preparation tank preferably comprises a main tank and an auxiliary tank. The main tank and the auxiliary tank are communicated at the bottom. Then, the resin varnish is refluxed to the preparation tank by allowing the resin varnish to flow down along the wall surface of the auxiliary tank. By doing so, generation of bubbles is suppressed when the resin varnish is refluxed. In addition, by separating the preparation tank into an auxiliary tank and a main tank, the bubbles in the auxiliary tank do not directly reach the main tank, and the auxiliary tank is allowed to settle and then mixed with the resin varnish of the main tank. At this time, the solvent is appropriately added and the concentration of the resin varnish is adjusted.

[0009]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to FIG.
Will be described with reference to. Preparation tank 2 for resin varnish 1,
A point provided with an impregnation tank 3 and a resin varnish receiving tank 4 overflowing from the impregnation tank 3, a point where the resin varnish 1 of the preparation tank 2 is supplied from the bottom opening 31 of the impregnation tank to the impregnation tank 3, and
The point that piping is provided so that the resin varnish that overflows from the impregnation tank 3 to the receiving tank 4 is returned to the preparation tank 2 is similar to the configuration described in the related art. The continuous sheet-shaped fibrous base material 11 that is sequentially transferred is drawn into the resin varnish of the impregnation tank 2 and, after a predetermined impregnation operation, is introduced into a drying furnace and becomes a prepreg through a heating and drying step.

In the above structure, the impregnation tank 3 is provided with the bubble removing member 5. The bubble removing member 5 is installed on the liquid surface of the resin varnish. Specifically, the sheet-shaped fiber base material 11
Position 6 of resin into the resin varnish and bottom opening 3 of impregnation tank 3
The bubble removing member 5 is installed between the position immediately above 1 and the position above 1. The location where bubbles are generated in the impregnation tank 3 is mainly near the bottom opening 31 that supplies the resin varnish to the impregnation tank 3. Bottom opening 3
The bubbles generated in the vicinity of 1 float almost directly above and float on the liquid surface of the resin varnish. Therefore, by arranging the bubble removing member 5 at the above position, it is possible to prevent bubbles floating on the liquid surface of the resin varnish from moving to the drawing-in position 6 of the sheet-shaped fiber base material. The bubble removing member 5 is composed of, for example, a roll 51 that is partially exposed on the liquid surface of the resin varnish and rotates, and a doctor knife 52 that abuts on the peripheral surface of the roll. The roll 51 rotates in a direction that prevents the bubbles from moving toward the retracted position 6, and the doctor knife 52 scrapes off the bubbles attached to the circumferential surface of the roll. The roll 51 blocks the bubbles floating from the vicinity of the bottom opening 31 to the liquid surface of the resin varnish and floating toward the drawing-in position 6. In addition, bubbles floating between the roll 51 and the retracted position 6 are also attracted to the roll 51. The bubbles attached to the peripheral surface of the roll 51 are
As it is, it reaches the position of the doctor knife 52 (the position on the opposite side of the retracted position 6 with the roll 51 sandwiched between them) and is scraped off there. As a result, bubbles attached to the sheet-shaped fiber base material 11 can be further reduced.

The impregnation tank 3 preferably has a shallow bottom in the range from the bottom opening 31 to just below the installation of the bubble removing member 5.

The resin varnish supplied from the preparation tank 2 to the impregnation tank 3 has been set to a predetermined concentration in the preparation tank 2.
In order to homogenize and stabilize the characteristics of the resin varnish in the impregnation tank, the resin varnish in the impregnation tank 3 is allowed to overflow into the receiving tank 4 and is further refluxed to the preparation tank 2 to adjust the concentration. The reflux may be carried out as follows. That is, the preparation tank 2 is composed of the main tank 21 and the auxiliary tank 22. Then, the resin varnish is refluxed in the auxiliary tank 22. At this time,
The resin varnish flows down the wall surface of the auxiliary tank 22 from above the liquid level of the resin varnish in the auxiliary tank. Specifically, the return pipe 7
The tip opening of the above is brought into contact with the wall surface of the auxiliary tank 22. By doing so, it is possible to suppress the generation of bubbles when the resin varnish is refluxed to the preparation tank 2. Further, when the solvent shower device 8 is installed in the auxiliary tank 22 and sprayed on the liquid surface of the resin varnish, the defoaming action can be provided in addition to the concentration adjustment of the resin varnish.

The sheet-like fiber base material which is impregnated with the resin varnish using the above-mentioned impregnating device is a glass woven cloth, a glass nonwoven cloth,
There is no particular limitation on the type, such as organic fiber woven fabric, organic fiber non-woven fabric, and fibrous base paper. The weaving density, thickness, unit mass, etc. are also appropriately determined. Also, the resin varnish is not particularly limited in type, such as epoxy resin, polyimide resin, phenol resin, polyester resin.
The resin concentration and viscosity of the resin varnish impregnated into the sheet-shaped fiber base material differ depending on the resin content required for the prepreg, but usually, the resin concentration is 40 to 80% by mass and the viscosity is 0.01
-1 Pa · s or the like is used.

[0014]

Example 1 Using the resin varnish impregnating device described with reference to FIG. 1, a prepreg was manufactured as follows. The resin varnish used is an epoxy resin varnish in which rubber elastic fine particles that are incompatible with the epoxy resin are dispersed. This resin varnish
In the preparation tank 2, the resin concentration was adjusted to 65% by mass and the viscosity was adjusted to 0.
After adjusting the pressure to 1 Pa · s, it is supplied to the impregnation tank 3. The sheet-shaped fiber base material 11 impregnated with this epoxy resin varnish is
It is a glass woven fabric of IPC standard 1080 type (thickness of 50 μm) and is passed through the resin varnish of the impregnation tank 3 at a speed of 5 m / min. After being drawn out from the impregnation tank, it was heated and dried to obtain a prepreg having a resin content of 60% by mass. Example 2 A prepreg is manufactured in the same manner as in Example 1. However, the preparation layer 2 was not separated into the main tank 21 and the auxiliary tank 22 as in Example 1, and had a single tank structure. The tip opening of the reflux pipe 7 contacts the wall surface of the preparation tank 2 according to the first embodiment. Further, the solvent was supplied by inserting the solvent supply pipe into the resin varnish without installing the shower device 8.

Example 3 A prepreg is manufactured in the same manner as in Example 2. However, the bottom of the impregnation tank 3 has a uniform depth, and the bottom in the range from the bottom opening 31 to just below the installation of the bubble removing member 5 is not particularly shallow unlike the first and second embodiments.

Conventional Example A prepreg was manufactured by using the resin varnish impregnating apparatus described with reference to FIG. The resin varnish and the sheet-shaped fiber base material used are the same as those in the above-mentioned examples.

Table 1 shows the results obtained by visually observing the surfaces of the prepregs manufactured in the above Examples and Conventional Examples and counting the number of repellants (small circular resin non-impregnated portions) per unit area (1 m ² ). Table 1 shows that a prepreg with less repellency can be produced by using the apparatus of Example, and the impregnation tank 3 is provided with a shallow bottom portion (Example 1,
It is shown that the repellency is further reduced in Example 2), and the repellency is further reduced in the structure in which the preparation tank is separated into the main tank and the auxiliary tank (Example 1).

[0018]

[Table 1]

[0019]

As described above, by using the resin varnish impregnating apparatus according to the present invention, it is possible to prevent bubbles generated in the resin varnish in the impregnation tank from adhering to the sheet-shaped fiber base material. It is possible to produce a prepreg having a good appearance in which impregnation of the resin varnish is not hindered by the presence of the prepreg.

[Brief description of drawings]

FIG. 1 is an explanatory view showing an embodiment of an impregnation device according to the present invention.

FIG. 2 is an explanatory view showing a conventional impregnation device.

[Explanation of symbols]

1: Resin varnish 2: Preparation tank 21: Main tank 22: Auxiliary tank 3: Impregnation tank 31: Bottom opening 4: Receiving tank 5: Bubble removing member 51: Roll 52: Doctor knife 6: retracted position 7: Return piping 8: Shower device 11: Sheet fiber base material

Claims (5)

[Claims] 1. A preparation tank for resin varnish, an impregnation tank for impregnating a continuous sheet-like fiber base material successively with resin varnish, and a tank for receiving resin varnish overflowing from the impregnation tank. In the resin varnish impregnation device in the prepreg manufacturing, the resin varnish of the tank is supplied to the impregnation tank through the bottom opening of the impregnation tank, and the resin varnish overflowing to the receiving tank is returned to the preparation tank. A resin varnish impregnating apparatus, characterized in that a foam removing member is installed on the surface, and the installation position is between a position where the sheet-shaped fiber base material is drawn into the resin varnish and a position directly above the bottom opening. 2. The bottom of the impregnation tank in the range from the bottom opening to just below the installation of the foam removing member is made shallow.
The resin varnish impregnation apparatus described. 3. The foam removing member is composed of a roll which is partially exposed on the liquid surface of the resin varnish and rotates, and a doctor knife which is in contact with the peripheral surface of the roll, and the roll is foamed toward a retracted position. The resin varnish impregnating apparatus according to claim 1 or 2, wherein the doctor knife is rotated in a direction in which movement of the resin knife is prevented, and the doctor knife scrapes off bubbles adhering to the peripheral surface of the roll. 4. The preparation tank comprises a main tank and an auxiliary tank, the main tank and the auxiliary tank communicate with each other at a lower portion, and the resin varnish flows back to the preparation tank by flowing down the wall surface of the auxiliary tank. The resin varnish impregnating device according to any one of claims 1 to 3, wherein 5. The resin varnish impregnating device according to claim 4, wherein a shower device for a solvent is arranged in the auxiliary tank.