JPH0583046B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a sheet-like base material made of a fibrous material such as paper or cloth used for manufacturing laminates such as electrical insulating boards and decorative boards. The present invention relates to a method and apparatus for impregnating water with varnish.

[Conventional technology]

Generally, when impregnating a sheet-like base material made of fibrous material with varnish, it is important that the varnish is impregnated into the inside of the fibers of the base material and that the amount of varnish is evenly distributed in each part. It is desirable to reduce the number of air bubbles remaining in the material as much as possible.

In conventional impregnation methods, the substrate is generally pre-impregnated with an ordinary varnish for pre-impregnation, and then guided through a timing roll to a varnish tank where it is impregnated with an ordinary varnish. be.

However, with such an impregnation method, it is difficult to uniformly and sufficiently impregnate the inside of the base material with varnish, and there are problems in that it takes a long time to impregnate the base material with varnish. Furthermore, it is difficult to sufficiently reduce the number of bubbles remaining in the base material. This problem becomes particularly noticeable when a high viscosity varnish is used.

Therefore, in recent years, instead of the normal varnish for preliminary impregnation mentioned above, a preliminary impregnation tank that stores a solvent or a dilute varnish containing a large amount of solvent (hereinafter referred to as "preliminary impregnation liquid") and a main impregnation tank that stores a normal varnish. It has been practiced to arrange these in parallel and allow the base material to pass through the preliminary impregnation tank and the main impregnation tank sequentially using guide rolls.

According to this impregnation method, while the substrate is passed through the pre-impregnating liquid, the air in the substrate is replaced with the pre-impregnating liquid and removed, so that the pre-impregnating liquid impregnated in the substrate is removed. When the liquid is introduced into the varnish while being evaporated, the varnish can be impregnated efficiently and bubbles can be reduced.

[Problem to be solved by the invention]

However, in the transition stage from the pre-impregnating liquid to the varnish, the base material is exposed to air and is compressed by the guide rolls between the two tanks, so air in the base material is not removed sufficiently and the varnish is Impregnating properties and voidless effects cannot be expected.

That is, when the base material reaches the guide roll,
Contact surface pressure acts on the fiber bundles that make up the base material,
The fiber bundle is opened, and the liquid phase of the pre-impregnation liquid held by capillary forces within the fiber bundle is destroyed. The compression of the fiber bundle is released when it passes through this guide roll, but the opened fiber bundle is reformed by this decompression action. As described above, since the destruction of the impregnating liquid phase in the fiber bundle and the reformation of the opened fiber bundle take place in the air, air is present in the base material during the transition stage from the pre-impregnating liquid to the varnish. There is a risk of re-invasion.

The present invention has been made in view of these points,
The object of the present invention is to provide a varnish impregnation method that can significantly improve the varnish impregnation properties and void-free effect in a base material, and a varnish impregnation apparatus that can suitably carry out the method.

[Means to solve the problem]

The varnish impregnation method of the present invention solves this problem by providing a varnish impregnation method between a low viscosity liquid storage area where a low viscosity liquid such as a solvent can be stored and a varnish storage area where varnish can be stored.
A sealed thermosiphon region is provided in both reservoir regions, which communicate with each other while being sealed with liquid at the liquid level, and a sheet-like base material made of a fibrous material is used as a low-viscosity liquid reservoir region, a thermosyphon region, and a varnish reservoir region. At the same time, in the thermosiphon region, the base material is heated to evaporate the low viscosity liquid impregnated therein, and the low viscosity liquid vapor generated in the region is condensed and liquefied. The liquefied low-viscosity liquid is collected into the low-viscosity liquid storage area, and the low-viscosity liquid is heated and evaporated in the communication area between the thermosiphon area and the low-viscosity liquid storage area, and the amount of evaporation is measured in the communication area. Control is performed according to fluctuations in the liquid sealing surface.

On the other hand, the varnish impregnation apparatus of the present invention for carrying out such a method includes a low viscosity liquid storage tank storing a low viscosity liquid such as a solvent, a varnish storage tank storing varnish, and a liquid level below the liquid level in each storage tank. A closed thermosyphon chamber with a cylindrical base material inlet opening and a base material outlet vertically installed; A base material running guide mechanism that guides the base material through the thermosyphon chamber and further leads it from the base material outlet to the varnish storage tank, and a base material heating system that heats the base material in the thermosyphon chamber and evaporates the low-viscosity liquid impregnated into the base material. a cooling mechanism that condenses and liquefies the low-viscosity liquid vapor in the thermosiphon chamber; a condensate recovery mechanism that recovers the low-viscosity liquid condensed and liquefied by the cooling mechanism into the low-viscosity liquid storage tank; A low viscosity liquid configured such that a low viscosity liquid heating surface extending vertically is disposed in the low viscosity liquid reservoir so that the amount of heating and evaporation of the low viscosity liquid changes as the liquid level in the low viscosity liquid reservoir changes. A heating mechanism is provided.

[Effect]

While the substrate passes through the low viscosity liquid reservoir, the air in the substrate is replaced with the low viscosity liquid and removed.

The base material impregnated with the low viscosity liquid is then brought into the thermosyphon chamber from the base material inlet and heated by the base material heating mechanism. By heating the base material, the low viscosity liquid impregnated therein is evaporated and separated.

At this time, the vapor pressure in the thermosiphon chamber is maintained within a certain range as long as the amount of evaporation of the low viscosity liquid by the base material heating mechanism and the low viscosity liquid heating mechanism and the amount of condensation by the cooling mechanism are in equilibrium. If the varnish impregnation conditions, such as the running speed of the substrate, are changed or fluctuated, the balance between the amount of evaporation and the amount of condensation will be disrupted, which may cause the steam pressure in the thermosyphon chamber to fluctuate, making it impossible to perform the above-mentioned functions properly. There is.

However, when the steam pressure in the thermosiphon chamber fluctuates, the liquid level in the low-viscosity liquid reservoir (and the liquid level in the varnish reservoir) also fluctuates, and the amount of evaporation by the low-viscosity liquid heating mechanism changes accordingly. It will be automatically controlled. In other words, when the vapor pressure decreases and the liquid level in the low-viscosity liquid reservoir rises, the amount of immersion of the low-viscosity liquid heating surface in the low-viscosity liquid reservoir, that is, the contact area between the low-viscosity liquid and the low-viscosity liquid heating surface increases. As a result, the amount of evaporation caused by the low-viscosity liquid heating mechanism increases by an amount corresponding to the amount of decrease in steam pressure, thereby preventing fluctuations in steam pressure in the thermosyphon chamber. Conversely, when the steam pressure increases, the liquid level in the low viscosity liquid reservoir falls, and the contact area between the low viscosity liquid and the low viscosity liquid heating surface decreases, and therefore the low viscosity liquid heating mechanism The amount of evaporation decreases,
Prevents steam pressure from increasing.

In this way, the steam pressure in the thermosiphon chamber is self-controlled and always maintained within a certain range without the need for a pressure control device or the like. Moreover, in cases such as when the base material travel is stopped due to an operational stop or when the base material travel speed is changed or fluctuated, the amount of condensation caused by the cooling mechanism significantly exceeds the amount of evaporation caused by heating the base material. However, there is a risk that the thermosiphon chamber will become vacuum or negative pressure, causing problems such as low viscosity liquid and varnish being sucked up into the thermosyphon chamber from the substrate inlet and substrate outlet. In this case, such inconvenience does not occur at all.

Further, since the low viscosity liquid condensed by the cooling mechanism is collected into the low viscosity liquid storage tank, the loss of the low viscosity liquid and the intrusion into the varnish storage tank are prevented as much as possible.

Therefore, in the thermosyphon region, the substrate will function well as a thermosiphon wick, and the substrate will flow from the thermosyphon region to the varnish reservoir region with only saturated vapor of a low viscosity liquid. It will be brought to you. That is, no air enters the substrate during the transition stage from the low viscosity liquid reservoir region to the varnish reservoir region, resulting in an air-free substrate in the varnish region.

As a result, when the substrate is brought to the varnish storage area, the impregnation of the substrate with varnish takes place well, and the substrate is evenly and thoroughly impregnated with varnish.

〔Example〕

Hereinafter, the configuration of the present invention will be specifically explained based on the embodiment shown in FIG.

In the varnish impregnation apparatus shown in FIG. 1, 1 is a base material, 2 is a low viscosity liquid storage tank, 3 is a varnish storage tank, and 4
5 is a thermosiphon chamber, 5 is a substrate heating mechanism, 6 is a cooling mechanism, 7 is a low viscosity liquid evaporation mechanism, 8 is a condensate recovery mechanism, and 9 is a substrate travel guide mechanism.

The base material 1 is a sheet-like material made of fibrous material,
Woven or nonwoven fabrics made of synthetic, natural, organic, or inorganic fibers, such as paper, glass fiber fabric, glass fiber nonwoven fabric, carbon fiber fabric, carbon fiber nonwoven fabric, aramid fiber fabric, aramid fiber nonwoven fabric, etc., are used.

The low viscosity liquid storage tank 2 has an open top and stores a predetermined amount of a low viscosity liquid 12 such as a solvent, and the varnish storage tank 3 has an open top and stores a predetermined amount of varnish 13. Overflow weirs 2a, 3b and overflow basins 2b, 3b are provided on the side walls of each storage tank 2, 3, and the liquid level in each storage tank 2, 3 is kept constant. be. In addition, overflow weir 2a,
The liquid 3b is returned to the storage tanks 2 and 3 by a return means (not shown). Further, the low viscosity liquid 12 and the varnish 13 are each maintained at a predetermined temperature by a temperature control device (not shown).

By the way, as the low viscosity liquid 12, one having sufficient wettability to the base material 1 is used. Specifically, it has a lower viscosity than Varnish 13 and
A solvent with a viscosity of 100 cP or less is used, but it is preferable to use a solvent of the same quality as the solvent blended into the varnish to be impregnated. Further, as the varnish 13, a thermosetting resin varnish is generally used, but other varnishes such as thermoplastic resins, natural resins, solvent-free liquid synthetic resins, liquid natural resins, etc. can also be used.

The thermosiphon chamber 4 is disposed in the upper part between the two storage tanks 2 and 3, and has a cylindrical base material inlet part 4 on the bottom wall.
It has an inverted U-shaped siphon tube shape with a vertical base material outlet section 4a and a base material outlet section 4b. Base material entrance part 4
a and the base material outlet portion 4b, respectively, the liquid levels 12' and 1 of the low viscosity liquid storage area 2' and the varnish storage area 3'.
The thermosyphon chamber 4 is opened at the bottom 3'.
A thermosiphon region 4' is formed inside which is sealed by a liquid seal. Further, an inert gas supply pipe 14, an exhaust pipe 15, and a bleed pipe 16 are connected to the thermosiphon chamber 4. The air bleed pipe 16 is led to the low viscosity liquid storage tank 2, and is provided with an air bleed valve 16a.
Note that the peripheral wall of the thermosyphon chamber 4 including the substrate inlet section 4a and the substrate outlet section 4b is configured as a heat insulating wall, and the low viscosity liquid vapor is cooled by the outside air and condensed on the inner wall surface of the thermosyphon chamber 4. It is designed to prevent it from sticking.

The substrate heating mechanism 5 includes a heating roll 5 a rotatably provided in the thermosiphon chamber 4 to follow the movement of the substrate 1 . This heating roll 5a heats the base material 1 to a temperature equal to or near the boiling point of the low-viscosity liquid 12 in the thermosyphon region 4', thereby evaporating the low-viscosity liquid 12 impregnated therein. By the way, the heating temperature of the base material by the heating roll 5a is controlled by a temperature control device (not shown), but its evaporation capacity is determined by the maximum amount of evaporation that is impregnated into the base material 1 and brought into the thermosyphon chamber 4. It is said to be sufficient to evaporate viscous liquids. In addition,
The heating roll 5a may be driven to rotate in the direction in which the base material 1 passes. In this case, it goes without saying that the peripheral speed of the roll should match the traveling speed of the base material 1.

The cooling mechanism 6 is for cooling and condensing the low-viscosity liquid vapor in the thermosyphon region 4', and includes a first cooling coil 6a disposed above the low-viscosity liquid reservoir 12a at the base material inlet portion 4a; , and a second cooling coil 6b disposed above the varnish reservoir 13a at the base material outlet portion 4b. By the way, the first
The cooling capacity, that is, the condensing capacity, of the cooling coil 6a is sufficient to condense all of the low viscosity liquid evaporated by the heating roll 5a. In other words, the evaporation capacity is greater than the evaporation capacity of the heating roll 5a. Further, the condensing capacity of the second cooling coil 6b is lower than that of the first cooling coil 6a, and is about 10 to 20% thereof. Note that the space between each cooling coil 6a, 6b and the peripheral wall of the thermosyphon chamber 4 is insulated, so that there is no inconvenience caused by the cooling action of the cooling coils 6a, 6b being applied to the peripheral wall (low viscosity liquid vapor is directed to the inner surface of the peripheral wall). The aim is to prevent condensation (condensation and adhesion).

The low-viscosity liquid heating mechanism 7 heats and evaporates the low-viscosity liquid in the low-viscosity liquid reservoir 12a, and includes, for example, a vertically extending low-viscosity liquid heating surface 7a formed of a heat transfer coil that causes a heating medium to flow inside. is arranged in a low viscosity liquid reservoir 12a. By the way, the heating capacity of the low viscosity liquid heating mechanism 7, that is, the evaporation capacity of the low viscosity liquid, is sufficient to ensure at least the amount of evaporation equivalent to the amount of condensation (total amount) by both the cooling coils 6a and 6b. . Note that the space between the low-viscosity liquid heating surface 7a and the peripheral wall of the thermosiphon chamber 4 is insulated to prevent the heat in the low-viscosity liquid reservoir 12a from being transmitted to the surrounding low-viscosity liquid 12 as much as possible. .

The condensate recovery mechanism 8 includes a condensate reservoir 8a connected to the inner circumferential portion of the base material outlet portion 4b immediately below the second cooling coil 6b, and a low viscosity liquid reservoir 2 (more specifically, Specifically, by guiding the collection pipe 8b to the low viscosity liquid reservoir 2b) at the base material inlet 4a,
The low viscosity liquid condensed by the second cooling coil 6b is collected into the low viscosity liquid reservoir 2b. Further, the low viscosity liquid condensed by the first cooling coil 6a is collected into the low viscosity liquid reservoir 2b using the base material inlet portion 4a as it is. Note that the constituent wall 8c of the condensation tank 8a is
A heat insulating wall is formed between the base material 1 and the second cooling coil 6b, and the base material 1 is radiatively cooled by the cooling coil 6b, so that low viscosity liquid vapor flows into the base material 1.
This is intended to prevent condensation and adhesion.

The base material traveling guide mechanism 9 includes at least guide rolls 9a..., 9b disposed in each storage tank 2, 3.
..., and the base material 1 is the base material supply source (not shown)
to the low viscosity liquid storage tank 2, and the base material inlet part 4a
to the low viscosity liquid heating surface 7a and the first cooling coil 6a.
It passes through the thermosyphon chamber 4, passes through the heating roll 5a and the second cooling coil 6b, and reaches the inside of the varnish storage tank 3 from the base material outlet section 4b, and the varnish impregnation amount adjustment mechanism on the varnish storage tank 3. 17. Note that the guide rolls 9 disposed in each storage area 2', 3'
A part of a..., 9b... is configured as an expander type that can apply stretching force to the base material 1 in its width direction, and is configured to have an expander type that can apply stretching force to the base material 1 in the width direction. , the replacement of air and low viscosity liquid in the low viscosity liquid storage area 2' and the impregnation of varnish in the varnish storage area 3' are promoted. The varnish impregnation amount adjustment mechanism 17 is composed of a squeeze roll or a squeeze bar, and squeezes the base material 1 that has passed through the varnish storage tank 3 to adjust the varnish impregnation amount.

Next, the method of the present invention will be specifically explained using the varnish impregnation apparatus configured as described above.

To start up the device, the inside of the thermosyphon chamber 4 is filled with saturated steam of a low viscosity liquid and the pressure of the steam is maintained within a certain range as follows.

That is, inert gas is supplied to the thermosiphon chamber 4 from the supply pipe 14, and air in the thermosyphon chamber 4 is removed from the exhaust pipe 15. At this time, the inside of the thermosiphon chamber 4 is maintained at atmospheric pressure. Therefore, the liquid level 12'a of the low viscosity liquid reservoir 12a and the varnish reservoir 13a,
13'a is located at the same height as the liquid levels 12', 13' of the storage tanks 2, 3 (see solid line in FIG. 1).

Next, each of the heating mechanisms 5 and 7 is operated, and low viscosity liquid vapor is mainly generated in the thermosiphon chamber 4 by the low viscosity liquid heating mechanism 7. At the same time, only the second cooling coil 6b with low cooling capacity is operated to condense the low viscosity liquid vapor. Therefore, since the first cooling coil 6a with high cooling capacity is not operated, the amount of evaporation by both heating mechanisms 5 and 7 exceeds the amount of condensation by the second cooling coil 6b, and the thermosiphon chamber 4
The steam pressure inside increases.

At this time, when the bleed valve 16a is forcibly opened, excess steam in the thermosyphon chamber 4 is removed from the bleed pipe 16 to the low-viscosity liquid storage tank 2, and the inside of the thermosyphon chamber 4 is maintained at atmospheric pressure. On the other hand, each sealing liquid surface 12'a,
13'a does not change and is maintained at the position shown by the solid line in FIG. Further, the low viscosity liquid condensed by the second cooling coil 6b is collected in the condensed liquid reservoir 8a, and is recovered from the recovery pipe 8b into the low viscosity liquid reservoir 12a. This prevents the low viscosity liquid vapor from condensing on the varnish storage area 3' side.

By repeating this action, the inert gas in the thermosyphon chamber 4 is expelled, and the thermosiphon chamber 4 is
The interior will be filled with low viscosity liquid vapor.

When the inside of the thermosyphon chamber 4 is filled with low viscosity liquid vapor, the bleed valve 16a is forcibly closed, and the pressure inside the thermosyphon chamber 4 is increased. At this time, as the pressure inside the thermosyphon chamber 4 increases, each sealing liquid surface 12'a,
13'a descends (see the chain line in Figure 1). As the liquid level 12'a of the low-viscosity liquid reservoir 12a falls, the immersion depth of the low-viscosity liquid heating surface 7a in the low-viscosity liquid reservoir 12a decreases, and the contact area between the heating surface 7a and the low-viscosity liquid increases. decreases, and the low viscosity liquid heating mechanism 7
As the amount of evaporation decreases, the second cooling coil 6
It will be in equilibrium with the amount of condensation b.

Subsequently, when the first cooling coil 6a is operated, the amount of condensation of the low-viscosity liquid vapor increases, the pressure inside the thermosyphon chamber 4 decreases, and each sealing liquid surface 12'a, 1
3' rises. Liquid level 12'a of low viscosity liquid reservoir 12a
As the temperature rises, the contact area between the low viscosity liquid heating surface 7a and the low viscosity liquid increases, and the amount of evaporation by the low viscosity liquid heating mechanism 7 increases, causing the cooling coils 6a, 6
This results in equilibrium with the condensation amount of b, and the steam pressure within the thermosyphon chamber 4 is maintained within a certain range.

When the base material 1 is run in this state, the base material 1 is impregnated with varnish in the following manner.

That is, the substrate 1 is brought into the low viscosity liquid storage tank 2 from the substrate supply source and immersed in the low viscosity liquid 12, and the air in the substrate 1 is replaced with the low viscosity liquid 12. At this time, the base material 1 is at the liquid level 1 of the low viscosity liquid 12.
2', the low viscosity liquid 12 impregnates the fiber bundle constituting the base material 1 by capillary action, and at the same time, the air in the fiber bundle is pushed out by its penetrating force. Such osmotic action stops at some stage due to osmotic resistance in the fiber bundle. In other words, the stopping of the permeation action is determined by the traveling speed of the base material 1, that is, the low viscosity liquid 1 of the fiber bundle.
If the rate of entry into 2 is greater than the rate of penetration, it will occur above the liquid surface, and vice versa, it will occur below the liquid surface. Therefore, while the base material 1 passes through the low-viscosity liquid storage area 2', all the air in the fiber bundle is replaced with the low-viscosity liquid 12 and eliminated.

The base material 1 impregnated with the low viscosity liquid 12 is
The low viscosity liquid 12 impregnated into the base material 1 is evaporated and removed by being brought into the thermosyphon chamber 4 from the base material inlet portion 4a and heated by the heating roll 5a.

At this time, the base material 1 moves through the low viscosity liquid 1 at its advancing speed.
Since the base material 2 continues to be supplied to the base material heating section 5a, the base material 1 plays the role of a thermosiphon.

On the other hand, the steam pressure in the thermosiphon chamber 4 is maintained within a certain range by the following self-control.

That is, when the steam pressure in the thermosyphon chamber 4 changes, the liquid level 1 of the low viscosity liquid reservoir 12a changes accordingly.
2'a (and the liquid level 13'a of the varnish reservoir 13a) also fluctuates, and the amount of evaporation by the low-viscosity liquid heating mechanism 7 is automatically controlled according to the amount of fluctuation. For example, when the vapor pressure decreases and the liquid sealing surface 12'a rises, the contact area between the low viscosity liquid in the low viscosity liquid reservoir 12a and the low viscosity liquid heating surface 7a increases (for example, a solid line state), and the low viscosity liquid The amount of evaporation caused by the heating mechanism 7 increases by an amount corresponding to the amount of decrease in steam pressure,
This prevents a drop in steam pressure within the thermosyphon chamber 4. Conversely, if the steam pressure increases, the sealing liquid surface 12'
a decreases, the contact area between the low viscosity liquid and the low viscosity liquid heating surface 7a decreases (for example, in a chain line state), the amount of evaporation by the low viscosity liquid heating mechanism 7 decreases, and a rise in vapor pressure is prevented. do.

Further, most of the steam generated by the base material heating mechanism 5 is condensed by the first cooling coil 6a and collected from the base material inlet portion 4a into the low viscosity liquid reservoir 12a. On the other hand, at the base material outlet section 4b, the low viscosity liquid vapor is condensed by the second cooling coil 6b, and the condensed liquid is collected into the low viscosity liquid reservoir 12a from the collection pipe 8b. As a result, in combination with the above-mentioned self-control of the steam pressure, the low viscosity liquid is successfully separated from the base material 1, and the loss of the low viscosity liquid 12 and the intrusion into the varnish storage tank 3 are minimized. This will be prevented.

Therefore, the base material 1 heated in the thermosyphon chamber 4 only contains saturated vapor of the low viscosity liquid 12, and is brought into the varnish storage tank 3 from the base material outlet portion 4b in a state containing no air. , immersed in varnish 13.

Then, when the low-viscosity liquid-saturated vapor contained in the base material 1 enters the varnish storage region 3', it becomes a trace amount of low-viscosity liquid-saturated liquid and diffuses into the varnish 13.

Therefore, while the base material 1 passes through the varnish storage area 3', the base material 1 is uniformly and sufficiently impregnated with the varnish 13.

At this time, as described above, most of the low-viscosity liquid vapor generated in the thermosyphon chamber 4 is recovered to the low-viscosity liquid storage tank 2 side, and is brought directly into the varnish storage tank 3 by the base material 1. Since the amount of low viscosity liquid saturated steam is small, the viscosity of the varnish in the varnish storage tank 3 does not decrease. In addition, base material 1
When passing through the expander type guide rolls 9a and 9b, a stretching force is applied in the width direction, and this stretching force is canceled after passing through the rolls, so that the low viscosity liquid 1
2 and the varnish 13, the fiber bundles in the width direction are also expanded and reconverged, thereby improving air/low viscosity liquid replacement and varnish impregnation in the width direction. As a result, the inside of the fiber bundle of the base material 1 is sufficiently impregnated with the varnish 13.

〔Effect of the invention〕

As can be easily understood from the above explanation, according to the method of the present invention, a base material can be impregnated with varnish uniformly and in a sufficiently short time, and there is no foaming in the base material. I can do it. This effect is significant when impregnating high viscosity varnishes.

Moreover, according to the method of the present invention, fluctuations in the steam pressure in the thermosiphon region are interpreted as fluctuations in the liquid sealing surface in the communication portion with the low viscosity liquid storage region, and low viscosity liquid vapor is generated in accordance with the fluctuations in the liquid sealing surface. Since the amount is controlled, the steam pressure in the thermosiphon region can always be maintained within a certain range, and good varnish impregnation can be performed regardless of changes or fluctuations in varnish impregnation conditions such as substrate speed. can.

Furthermore, in the transition stage from the low viscosity liquid to the varnish, the substrate is heated and most of the low viscosity liquid is evaporated and separated, so loss of the low viscosity liquid and dilution of the varnish can be effectively prevented, and the impregnation effect can be effectively prevented. It is possible to promote different types of activities. Moreover, the amount of low viscosity liquid used in the base material is extremely small, and the amount of exhaust air from the drying oven in the drying process after impregnation with varnish can be significantly reduced.

Further, according to the apparatus of the present invention, the above method can be carried out suitably, and in particular, the steam pressure in the thermosiphon chamber can be adjusted to change the contact area between the low viscosity liquid and the low viscosity liquid heating surface in the low viscosity liquid reservoir. Since the system is self-controlled, there is no need for a high-precision pressure control device or the like, and the device structure does not become unnecessarily complicated or large. Furthermore, the steam pressure in the thermosiphon chamber can be controlled more reliably and accurately than when using a pressure control device or the like. moreover,
Even if the thermosyphon chamber becomes a vacuum or negative pressure state, such as when the operation is stopped, we can prevent this situation from occurring and prevent low viscosity liquids and varnish from being sucked up into the thermosyphon chamber. It does not cause any inconvenience at all.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of a varnish impregnating apparatus according to the present invention. 1...Base material, 2...Low viscosity liquid storage tank, 2'...
Low viscosity liquid storage area, 3...varnish storage tank, 3'...
...Varnish storage area, 4...Thermosyphon chamber, 4'...
...thermosyphon region, 4a...base material inlet portion, which is a communication part between the thermosiphon region and the low viscosity liquid storage region, 4
b...Base material outlet part which is a communication part between the thermosiphon region and the varnish storage region, 5...Base material heating mechanism, 5a
...heating roll, 6...cooling mechanism, 6a...first
Cooling coil, 6b...Second cooling coil, 7...Low viscosity liquid heating mechanism, 7a...Low viscosity liquid heating surface, 8...
...Condensed liquid recovery mechanism, 9...Base material traveling guide mechanism,
12...Low viscosity liquid, 12a...Low viscosity liquid reservoir, 1
2'a...Liquid level of low viscosity liquid reservoir which is liquid sealing surface, 13...
...Varnish, 13a...Varnish reservoir, 13'a...Liquid level of varnish reservoir, which is a liquid sealing surface.

Claims (1)

[Claims] 1. Between a low viscosity liquid storage area where a low viscosity liquid such as a solvent can be stored and a varnish storage area where varnish can be stored,
A sealed thermosiphon region is provided in both reservoir regions, which communicate with each other while being sealed with liquid at the liquid level, and a sheet-like base material made of a fibrous material is used as a low-viscosity liquid reservoir region, a thermosyphon region, and a varnish reservoir region. At the same time, in the thermosiphon region, the base material is heated to evaporate the low viscosity liquid impregnated therein, and the low viscosity liquid vapor generated in the region is condensed and liquefied. The liquefied low-viscosity liquid is collected into the low-viscosity liquid storage area, and the low-viscosity liquid is heated and evaporated in the communication area between the thermosiphon area and the low-viscosity liquid storage area, and the amount of evaporation is measured in the communication area. A varnish impregnation method characterized by controlling according to fluctuations in a liquid sealing surface. 2 A low viscosity liquid storage tank that stores low viscosity liquid such as a solvent, a varnish storage tank that stores varnish, and a cylindrical base material inlet and base material outlet that open below the liquid level in each storage tank. A vertically installed hermetic thermosiphon chamber and a sheet-like base material made of fibrous material are guided from a low-viscosity liquid storage tank through a base material inlet to a thermosiphon chamber, and then guided from a base material outlet to a varnish storage tank. a base material traveling guide mechanism, a base material heating mechanism that heats the base material in a thermosyphon chamber to evaporate a low viscosity liquid impregnated therein, and a cooling mechanism that condenses and liquefies the low viscosity liquid vapor in the thermosyphon chamber. , a condensed liquid recovery mechanism that collects the low viscosity liquid condensed and liquefied by the cooling mechanism into the low viscosity liquid storage tank side, and a low viscosity liquid heating surface extending vertically in the low viscosity liquid reservoir in the base material inlet section. A varnish impregnation device comprising: a low viscosity liquid heating mechanism configured to change the amount of heating and evaporation of the low viscosity liquid as the liquid level of the low viscosity liquid reservoir changes.