JPS63116770A - Varnish impregnation apparatus - Google Patents

Abstract

PURPOSE:To uniformly infiltrate varnish within a short time, by forming a reduced pressure zones between a vacuum drum and a plurality of compression rolls, a plurality of seal rolls or the like and forcibly infiltrating varnish into the sheet like base material passing through said zones by utilizing pressure difference. CONSTITUTION:A sheet like base material 13 made of cloth or the like is allowed to pass through the reduced pressure zones 3 formed to the periphery of a vacuum drum 2 and immersed in the varnish within a varnish tank 1 while compressed by compression rolls 4-6. When the sheet like base material 13 moves through the varnish in the state contacted with the peripheral wall 2b of the vacuum drum 2, since the vacuum drum 2 is evacuated, the varnish is forcibly penetrated and passed toward the center of the vacuum drum 2 to be infiltrated into the sheet like base material 13 within a short time. The sheet like base material 13 after impregnation passes through a varnish flow passage 7 sealed with the varnish formed around the drum and is further forcibly impregnated with the varnish to be fed out in a state of containing little air bubble.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a varnish for impregnating a sheet-like base material made of cloth or the like used in the production of laminates such as electrical insulating boards and decorative boards. Regarding an impregnating device.

(Prior art) Generally, when a sheet-like base material such as paper or cloth is impregnated with varnish, the varnish is impregnated to the center of the thickness of the sheet-like base material, and the distribution of the amount of varnish in each part is even and uniform. This is important, and it is desirable to minimize the number of air bubbles remaining in the sheet-like base material.

Conventional impregnating apparatuses are usually equipped with a varnish tank or the like storing varnish, and immerse a sheet-like base material in the varnish to impregnate the sheet-like base material with the varnish.

However, with this impregnating device, it is difficult to impregnate the varnish sufficiently and uniformly in the center of the thickness of the sheet-like base material.
However, there are problems in that it takes a long time even if the varnish is impregnated with the varnish. However, it is necessary to sufficiently reduce the number of air bubbles remaining in the sheet-like base material. In particular, this impregnating device was extremely unsuitable when using highly viscous varnishes.

Therefore, as a solution to these problems, the third
An 'if'ff varnish impregnation device shown in the figure has been developed.

That is, the varnish impregnation device has a reserve 111'72 in which dilute varnish containing only a solvent or a multi-claw containing a solvent is stored.
5, a varnish tank 27 in which ordinary varnish 26 is stored, and a plurality of rollers 29 that guide the sheet-like base material 28 to the varnish tank 27 via the preliminary tank 25, etc. After being immersed in the varnish in the a tank 25, it is immersed in the varnish 26 in the varnish tank 27 to impregnate the sheet-like base material 28 with the varnish 26. Compared to the above-mentioned impregnating apparatus, this varnish impregnation apparatus can improve impregnation of the varnish 26 into the center of the sheet-like base material 28, perform uniform impregnation, and reduce air bubbles. Can be done.

However, even in the varnish impregnation device, since the sheet-like base material 28 is simply immersed in the varnish 26,
When a thick sheet-like base material 28 or a sheet-like base material 28 with high liquid flow resistance is used, or when a highly viscous varnish 26 is used, there is inevitably a limit to the impregnating property, etc. It was not possible to significantly improve the impregnation of the varnish 26 into the center of the material 28. Furthermore, since this varnish impregnation apparatus uses a plurality of tanks 25 and 27, there is a problem in that the apparatus itself becomes large and requires a large installation space.

(Problems to be Solved by the Invention) The present invention was devised to solve one of the above problems, and its purpose is to efficiently and uniformly impregnate a sheet-like base material with varnish. It is an object of the present invention to provide a varnish impregnation device which can perform the varnish impregnation process and reduce the number of bubbles in a sheet-like base material.

(Means for Solving the Problems) The varnish impregnation device of the present invention has a varnish tank for storing varnish and a large number of holes in the peripheral wall around which the sheet-like base material is wound, and the inside is depressurized, and at least the peripheral wall is It is formed around a vacuum drum that is partially supported to be immersed in the varnish, and a part of the periphery of the vacuum drum that is located above the varnish liquid level, communicates with the vacuum drum, and allows the sheet-like base material to pass through. Located around the decompression zone and the decompression drum,
The peripheral wall of the vacuum drum, which is formed around the compression roll that compresses the sheet-shaped base material and the vacuum drum located above the varnish liquid level, is sealed with varnish, except for the area where the vacuum zone is formed, and the sheet-shaped base material is It is characterized in that it has a ti'/l relationship with the varnish channel through which the base material passes.

(Function) A sheet-like base material made of cloth or the like passes through a vacuum zone formed around a vacuum drum, and is immersed in varnish in a varnish tank while being compressed by a compression roll. Note that when the sheet-like base material passes through the reduced pressure zone, some of the air bubbles contained in the sheet-like base material are removed.

The sheet-like base material coated with the varnish moves through the varnish while being in contact with the peripheral wall of the vacuum drum.

At this time, the varnish is forcibly penetrated through the sheet-like base material toward the center of the vacuum drum due to the reduced pressure inside the vacuum drum, and is impregnated into the sheet-like base material in a short time. Also, some of the air bubbles contained in the sheet-like base material are removed by the reduced pressure action and movement of the varnish.

The sheet-like base material impregnated with varnish passes through a varnish channel formed around the vacuum drum and sealed with varnish while being in contact with the peripheral wall of the vacuum drum. At this time, the varnish in the varnish channel is forced to permeate through the sheet-like base material toward the center of the vacuum drum due to the reduced pressure in the vacuum drum. Thereby, air bubbles in the sheet-like base material are further removed.

Therefore, the varnish can be uniformly impregnated into the sheet-like base material in a short time, and the number of air bubbles in the sheet-like base material can be minimized.

(Example) Hereinafter, an example of the present invention will be described in detail based on the drawings.

FIG. 1 is a schematic vertical cross-sectional view of a varnish impregnation device according to an embodiment of the present invention, and the varnish impregnation device includes a varnish tank 11.
The groove is composed of a true pressure drum 2, a pressure reduction zone 3, compression rolls 4, 5.6, a varnish channel 7, and the like.

The varnish tank 1 has a box shape with an open top, and a suitable amount of varnish 8, such as thermosetting resin varnish, is stored inside. As the varnish 8, other than thermosetting resin varnish, thermoplastic resin, natural resin varnish, solvent-free liquid synthetic resin, liquid natural resin, etc. can also be used. A 14 is made up of a cylindrical peripheral wall 2b having a cylindrical peripheral wall 2b, a side wall 2c closing both ends of the peripheral wall 2b, and a hollow rotating shaft 2e having a plurality of holes 2d and inserted through and fixed at the axial center position of the peripheral wall 2b. A rotary member 1IilII2e is rotatably supported to immerse at least a portion of the peripheral wall 2b in the varnish 8 of the varnish tank l.

Further, the depressurizing drum 2 is designed to be depressurized inside, and in this embodiment, the rotating shaft 2e is connected to the suction pipe 9 and the valve 10.
By connecting to the vacuum pump 12 via the separation tank 11 and the like, the internal pressure can be reduced. When the pressure inside the vacuum drum 2 is reduced, a difference occurs between the level of the varnish 8 in the vacuum drum 2 and the level of the varnish 8 in the varnish tank 1. The opening position of the hole 2d of the rotating shaft 2e may be made variable so that it can be changed as appropriate depending on the moving speed of the material 13 and the characteristics and shape of the sheet-like base material 13. For example, a short tube (not shown) is welded to each hole 2d of the rotating shaft 2e, and a short tube (not shown) of a predetermined length is removably attached to the short tube, so that the opening position of each hole 2d can be varied. You can also do it. Furthermore, the decompression drum 2 is configured to be rotated at an appropriate speed by an appropriate driving device ff1 (not shown). In addition, the hole 2a of the peripheral wall 2b is
Holes of circular shape, slit shape, and other appropriate shapes can be used. Further, the density of the holes 2a is appropriately determined by taking into consideration the rate of impregnation of the varnish 8 into the sheet-like base material 13, etc.

The pressure reduction zone 3 is formed in a part of the periphery of the pressure reduction drum 2 located above the liquid level of the varnish 8, and is in communication with the pressure reduction drum 2.

That is, in this embodiment, the decompression zone 3 includes a plurality of compression rolls 4, 5, 6 and a plurality of seal rolls to form a closed space communicating with the inside of the decompression drum 2 around a part of the decompression drum 2. 14 and 15 are arranged so as to be rotatable in contact with each other, and by sealing both end surfaces of the vacuum drum 2 and each roll with a sealing material such as a rubber plate using a sealing mechanism (not shown), the surroundings of the vacuum drum 2 are sealed. is formed. Therefore, when the pressure inside the vacuum drum 2 is reduced, the air between the vacuum drum 2 and each roll is sucked into the vacuum drum 2 through the holes 2a, and the pressure in the vacuum zone 3 is also reduced.

Each of the compression rolls 4, 5.6 is connected to the peripheral wall 2 of the vacuum drum 2.
The sheet-like base material 13 is rotatably disposed in a state corresponding to b, and the sheet-like base material 13 is compressed between it and the seal roll 14, 15 or the vacuum drum 2.

Further, the compression roll 5 at the lowest position is arranged so that a part of its circumferential surface is immersed in the varnish 8.

As a result, the sheet-like base material 13 is dipped in the varnish 8 while being compressed.Furthermore, each compression roll 4,
5.6 is designed to be driven to rotate at approximately the same speed as the decompression drum 2 by an appropriate drive device (not shown). The reason for setting it to - is to prevent tension from being applied to the sheet-like base material 13. This is because if tension is applied to the sheet-like base material 13, the space in the sheet-like base material 13 becomes smaller, the liquid passage resistance increases, and the impregnating property of the varnish 8 deteriorates. .15 is pressure 1 approximately roll 4°5
．． It is rotatably supported in contact with the circumferential surface of 6.

The varnish channel 7 is formed around the vacuum drum 2 located above the liquid level of the varnish 8, and the varnish 8 flows down the peripheral wall 2b of the vacuum drum 2 other than the area where the vacuum zone 3 is formed. It is to be sealed. That is, in this embodiment, the varnish channel 7 covers a part of the circumference Wzb of the decompression drum 2 with a cover plate 16 at a constant interval, and the lower end of the cover plate 16 is immersed in the varnish 8 of the varnish tank 1. By doing so, cover plate 1
6 and the peripheral wall 2b. Further, a varnish reservoir 17 is provided on the upper part of the cover plate 16, and by flowing the varnish 8 from the varnish reservoir 17 into the varnish channel 7, the peripheral wall 2b of the depressurizing drum 2 is brought into a liquid-sealed state.

Furthermore, the cover plate 16 is connected to the cover plate 16 and the peripheral wall 2 of the vacuum drum 2.
Appropriate means (not shown) to adjust the distance from b.
The distance between the two is determined by the viscosity of the varnish 8, the amount of the varnish 8, and the sheet-like base material 13.
It can be determined as appropriate by taking into account the moving speed of the sheet, the characteristics and shape of the sheet-like base material 13, and the like. In order to maintain the reduced pressure in the vacuum drum 2, the varnish 8 in the separation tank 11 is supplied by a supply pipe 18 and a varnish circulation pump 19 so that the varnish 8 does not run out in the varnish reservoir 17. 17
The flow rate of the varnish 8 is controlled by a control valve 20 provided at the bottom of the varnish 8.

In FIG. 2, 21 is a varnish heater installed in the supply pipe 18 on the upstream side of the varnish circulation pump 19 to heat the varnish 8 to an appropriate temperature, and 22 is a varnish tank l and a varnish circulation pump. This is a bypass pipe that connects the supply pipe 18 on the upstream side of the varnish tank 19 to the supply pipe 18, which is used at the initial stage of startup, and supplies the varnish 8 in the varnish tank 1 to the varnish reservoir 17 and causes it to flow down in the varnish flow path 7. The periphery 92b of the vacuum drum 2 is sealed with liquid so that the pressure inside the vacuum drum 2 can be reduced.

23 and 24 are valves installed in the supply pipe 18 and the bypass pipe 22.

When the varnish impregnating device is used, the varnish 8 is caused to flow down into the varnish channel 7 while the vacuum pump 12 sucks the air in the vacuum drum 2 and the vacuum zone 3. 3. Reduce the pressure inside.

In this state, the sheet-like base material 13 passes between the compression roll 4 and the seal roll 15, and passes through the decompression zone 3 while being in contact with the peripheral wall 2b of the decompression drum 2 before being soaked in the varnish 8ff. . Note that when the sheet-like base material 13 passes through the decompression zone 3, some of the air bubbles contained in the sheet-like base material 13 are removed.

The sheet-like base material 13 that has passed through the vacuum zone 3 is not compressed between the compression roll 5 and the vacuum drum 2, but is immersed in the varnish 8, and is immersed in the varnish 8 while in contact with the peripheral wall 2b of the vacuum drum 2. Moving. At this time, the varnish 8 in the varnish tank 1 is forced to permeate through the sheet-like base material 13 toward the center of the vacuum drum 2 due to the reduced pressure inside the vacuum drum 2, and the varnish 8 in the varnish tank 1 is forcibly penetrated through the sheet-like base material 13 toward the center of the vacuum drum 2, and the sheet-like base material is Impregnated with 13. Further, some of the air bubbles contained in the sheet-like base material 13 are removed by the decompression action and the movement of the varnish 8.

The sheet-like base material 13 impregnated with the varnish 8 passes through the varnish channel 7 sealed with the varnish 8 while being in contact with the peripheral wall 2b of the vacuum drum 2. At this time, the varnish 8 flowing down in the varnish channel 7 is forcibly permeated through the sheet-like base material 13 toward the center of the vacuum drum 2 due to the reduced pressure in the vacuum drum 2 . As a result, air bubbles in the sheet-like base material 13 are further removed. Note that the varnish reservoir 17 is provided with the hole 2 of the rotating shaft 2e.
After the varnish 8 sucked together with air from d is separated in the separation tank 11, it is appropriately supplied via the varnish circulation pump 19, etc., so that the periphery of the decompression drum 2 is constantly The varnish 8 can be kept in a sealed state.The varnish 8 has been degassed in the separation tank 11.

Then, the sheet-like base material 13 passes through appropriately set gaps between the vacuum drum 2 and the compression roll 6, as well as between the compression roll 6 and the seal roll 15.
The amount of varnish 8 impregnated into the varnish 8 is appropriately controlled.

In this way, the sheet-like base material 1 impregnated with the varnish 8
No. 3 is used for laminates such as electrical insulating boards and decorative boards, insulating tapes, and wear-resistant materials such as brake linings.

The sheet-like base material 13 may include synthetic and natural organic/inorganic fiber cloths and nonwoven fabrics, such as paper, glass, fiber cloth, glass fiber nonwoven fabric, carbon resistant fiber fabric, carbon fiber nonwoven fabric, aramid iron fiber fabric, Aramid fiber non-woven fabric etc. are used.

(Effects of the Invention) As described above, the varnish impregnation apparatus of the present invention removes air bubbles contained in the sheet-like base material by passing the sheet-like base material through a reduced pressure zone, etc. Because the varnish is forced to penetrate and pass through using a pressure difference, the varnish can be uniformly impregnated into the sheet-like base material in a short time, regardless of the properties and types of the sheet-like base material and the varnish. Moreover, the number of air bubbles in the sheet-like base material can be minimized. As a result, by using the varnish impregnating apparatus of the present invention, the quality can be significantly improved.

In particular, the varnish impregnation device of the present invention is particularly effective when the varnish has high viscosity.

Furthermore, the varnish impregnating apparatus of the present invention does not require the use of multiple varnish tanks unlike conventional varnish impregnating apparatuses.
The device itself can be made smaller and requires less installation space.

[Brief explanation of the drawing]

Fig. 1 is a schematic vertical cross-sectional view of a varnish impregnating device according to an embodiment of the present invention, Fig. 2 is a schematic system diagram showing the flow of varnish in the varnish impregnating device, and Fig. 3 is a schematic vertical cross-sectional view of a conventional varnish impregnating device. It is a diagram. 1 is a varnish tank, 2 is a vacuum drum, 2a is a hole, 2b is a peripheral wall, 3 is a vacuum zone, 4, 5.6 are compression rolls, 7 is a varnish channel, 8 is a varnish, and 13 is a sheet-like base material. Figure 1 Figure 2 Figure 3

Claims (1)

[Claims] A large number of holes (
2a), the interior of which is reduced in pressure, and at least a portion of the peripheral wall (2b) is supported so as to be immersed in the varnish (8); and a vacuum drum (2) located above the varnish (8) liquid level. It is formed in a part of the periphery of the vacuum drum (2), communicates with the interior of the vacuum drum (2), and also connects the sheet-like base material (1
3) through which the vacuum zone (3) passes, and the vacuum drum (2).
Compression rolls (4), (5), (6) arranged around the sheet-like base material (13) to compress the sheet-like base material (13), and a vacuum drum (2) located above the liquid level of the varnish (8). A varnish channel is formed around the peripheral wall (2b) of the decompression drum (2) other than the part where the decompression zone (3) is formed, and is sealed with varnish (8), and the sheet-like base material (13) passes through it. (7) A varnish impregnation device characterized by comprising: