JPH106332A - Method for resin impregnation - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make an unimpregnated part hardly generate and to obtain a prepreg with excellent appearance by performing a method for feeding a resin varnish by feeding the resin varnish to a part surrounded with a base material of a part impregnated in the resin varnish and the liq. face of the varnish. SOLUTION: A inpregnation apparatus is constituted by providing a pipeline 20 with an opening part 21 to a part surrounded with a base material 14 of a part immersed in a resin varnish 12 and the liq. face of the resin varnish 12 and making the resin varnish in a resin receiving tank 13 flow from the opening part 21 by pressure by means of a pump p to feed the resin varnish 12 to the part between the base material and the liq. face. It is possible thereby to replace the amt. of the resin sticked on the base material 14 by feeding the resin varnish 12 with a viscosity adjusted to an appropriate value and the components becomes close to those of the resin varnish 12 whose viscosity is adjusted to be suitable for impregnation to the inside of the base material 14. Therefore, even when it is impregnated continuously, unimpregnated part is hardly generated to obtain a prepreg with excellent appearance.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for impregnating a resin, and more particularly to a method for producing a prepreg used for producing a printed wiring board used for electric / electronic equipment.

[0002]

2. Description of the Related Art Conventionally, a prepreg is manufactured by laminating a base material such as a glass cloth or the like with a resin varnish such as an epoxy resin and then drying and semi-curing the laminated board used for manufacturing a printed wiring board. A required number of such prepregs are stacked, and a metal foil such as a copper foil is arranged on one side or both sides of the prepreg as necessary, and then laminated, and then heated and pressed.

[0003] As a method of impregnating a base material with a resin varnish for producing a prepreg, for example, as shown in FIG.
An impregnating roll 11 driven inside the impregnating roll 11 is used, and the resin varnish 12 is filled in an impregnating tank 10 having an open system at an upper portion by using an impregnating device filled with the resin varnish 12 to such an extent that the impregnating roll 11 is sufficiently immersed. The base material 14 is supplied from the upper part of the impregnation tank 10, is continuously penetrated and submerged in the resin varnish 12, and then is wound around an impregnation roll 11 to change the direction. A method of pulling out from the upper portion and continuously impregnating the same has been performed.

A resin varnish 12 used in the above resin impregnation method
It is generally performed to adjust the viscosity by including a solvent in order to make the viscosity suitable for impregnating the inside of the base material 14 and to control the amount of resin adhering to the base material 14, When a prepreg is manufactured by a method using an open impregnation tank 10 as described above, the solvent easily evaporates from the upper liquid surface of the resin varnish 12 to change the viscosity, and unimpregnated portions of the resin are generated. In some cases, a portion with a large amount of resin adhered was generated, and the appearance of the prepreg was sometimes reduced.

For this purpose, a resin varnish 12 whose viscosity has been adjusted by replenishing a solvent 15 is continuously or intermittently supplied to the lower part of the impregnation tank 10 by pressurizing with a pump.
By removing the resin varnish 12 having a higher viscosity than the upper part of the base material by overflowing, a method of adjusting the viscosity suitable for impregnating the inside of the base material 14 and the amount of the resin adhering to the base material 14 has been studied. ing.

However, even when the resin varnish 12 whose viscosity has been adjusted is supplied from the lower part of the impregnation tank 10 to overflow the resin varnish 12 from the upper part of the impregnation tank 10, an unimpregnated portion is generated. In some cases, a portion having a large amount of resin adhered occurs, and the appearance of the prepreg is reduced. Therefore, there is a need for a resin impregnating method that hardly generates a non-impregnated portion and that can provide a prepreg having an excellent appearance.

[0007]

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a resin varnish containing a solvent in an impregnation tank having an open top. Is supplied and filled, while the resin varnish is continuously infiltrated with the base material and submerged in the resin varnish, and continuously withdrawn and impregnated, the unimpregnated portion hardly occurs, and An object of the present invention is to provide a resin impregnation method capable of obtaining a prepreg having an excellent appearance.

[0008]

According to a first aspect of the present invention, there is provided a resin impregnating method, wherein a resin varnish containing a solvent is supplied to and filled in an impregnation tank having an open system at an upper portion, and the resin varnish is filled with a base material. In the resin impregnation method in which the resin varnish is continuously drawn out and immersed in the resin varnish, and continuously withdrawn and impregnated, the method of supplying the resin varnish is surrounded by the base material and the liquid level of the resin varnish sinking into the resin varnish. The method is characterized in that a resin varnish is supplied to a portion (hereinafter referred to as a portion between the liquid surfaces of the base material).

[0009] The resin impregnation method according to claim 2 of the present invention comprises:
2. The resin impregnating method according to claim 1, wherein the method of supplying the resin varnish to the portion between the liquid surfaces of the base material includes providing a pipe having an opening in the portion between the liquid surfaces of the base material, and flowing the resin varnish from the opening portion. The method is characterized in that it is a method of supplying by means of:

[0010] The resin impregnation method according to claim 3 of the present invention comprises:
2. The resin impregnating method according to claim 1, wherein the method of supplying the resin varnish to the portion between the liquid surfaces of the base material impregnates the outlet for blowing the resin varnish so as to flow in the width direction of the base material within the portion between the liquid surfaces of the base material. The method is provided in a tank and supplied by blowing resin varnish.

[0011] The resin impregnation method according to claim 4 of the present invention comprises:
The resin impregnation method according to any one of claims 1 to 3, wherein the resin varnish in the resin varnish in the impregnation tank has a portion between the liquid surfaces of the base material and the resin varnish in the impregnation tank has a liquid surface between the base material and the liquid varnish. The difference in the viscosity of the resin varnish in the portion excluding the portion is 0 to 150
It is characterized in that a resin varnish is supplied to a portion between the liquid surfaces of the base material so as to have a centipoise.

[0012] The resin impregnation method according to claim 5 of the present invention comprises:
In the resin impregnation method according to any one of claims 1 to 4, the solvent contained in the resin varnish is methanol,
At least one selected from the group consisting of ethanol, methyl ethyl ketone, acetone, benzene, and toluene
It is characterized by containing a kind of solvent.

The resin varnish in the portion between the liquid surfaces of the base material has a lower viscosity than the resin varnish in the portion of the resin varnish in the impregnation tank except for the portion between the liquid surfaces of the base material because the solvent component evaporates from the liquid surface. The resin varnish tends to be high or the resin varnish having reduced impregnating property because air introduced by the base material floats in the liquid and impedes the impregnation. However, according to the present invention, a resin varnish suitable for impregnating the inside of the base material and having a viscosity adjusted so that the amount of resin adhering to the base material is also suitable, and a resin varnish in an impregnation tank in which a solvent component hardly evaporates. Because the resin varnish and the like in the portion excluding the portion between the liquid surfaces of the base material can be supplied to the portion between the liquid surfaces of the base material and can be replaced, compared with the case where the resin varnish is supplied from the lower part of the conventional impregnation tank, The resin varnish in the inter-plane portion has a higher viscosity due to the evaporation of the solvent component, and the resin varnish having reduced impregnation due to air floating in the liquid is reduced,
Resin varnish is suitable for impregnating the inside of the base material, and the amount of resin adhering to the base material is adjusted to a suitable viscosity. The components become close to the resin varnish and the like in the portion, and even if impregnated continuously, a non-impregnated portion hardly occurs and a prepreg excellent in appearance can be obtained.

[0014]

DESCRIPTION OF THE PREFERRED EMBODIMENTS A resin impregnation method according to the present invention will be described with reference to the drawings. FIG. 1 is a partially cutaway front view illustrating a first embodiment of a resin impregnation method according to the present invention, and FIG. 2 is a first embodiment of a resin impregnation method according to the present invention. FIG. 3 is a partially cutaway front view illustrating a second embodiment of the resin impregnation method according to the present invention, and FIG. 4
FIG. 4 is a partially cutaway side view illustrating a resin impregnation method according to a second embodiment of the present invention.

As shown in FIGS. 1 and 2, the resin impregnating method according to the first embodiment of the present invention includes an impregnating roll 11 driven inside thereof and an impregnating tank 10 having an open upper portion.
The resin varnish 12 is filled with the resin varnish 12 until the impregnation roll 11 is sufficiently immersed, and the resin varnish 12 is filled with the resin varnish 12 under the impregnation tank 10. Impregnation tank 1 with material 14
After being supplied from the upper portion of the impregnating tank 10 and continuously penetrating and submerging in the resin varnish 12, the direction is changed by winding it around the impregnating roll 11, and then the base material 14 is pulled out from the upper portion of the impregnating tank 10 to perform impregnation. Do.

The impregnating apparatus includes a portion A between the liquid surfaces of the base material.
A pipe 20 having an opening 21 is provided in a portion of the resin varnish 12 surrounded by the base material 14 and the liquid surface of the resin varnish 12, and the resin varnish of the resin receiving tank 13 is provided from the opening 21. The resin varnish 12 is supplied to the portion A between the liquid surfaces of the base material by pressurizing the pump 12 with the pump to flow out.

The impregnating apparatus is designed to adjust the viscosity by replenishing the solvent 15 while analyzing the viscosity of the resin varnish 12 in the resin receiving tank 13. High viscosity resin varnish 1
Even if 2 is added, it is adjusted so as to be suitable for impregnating the inside of the base material 14 and also to adjust the amount of resin adhering to the base material 14 to a suitable viscosity. Although not shown, the resin receiving tank 13 is replenished with a portion of the resin varnish 12 that is reduced by being taken out by being impregnated into the base material 14. The resin varnish 12 is filled up to the upper part of the impregnation tank 10.

The resin varnish 12 in the portion A between the liquid surfaces of the base material has a lower solvent level than the resin varnish 12 in the portion B of the resin varnish 12 in the impregnation tank 10 except the portion A between the liquid surfaces of the base material. Ingredients evaporate to increase the viscosity, or air introduced by the base material 14 floats in the liquid, and the air hinders impregnation, which tends to result in a resin varnish 12 having reduced impregnation. However, according to the present invention, the resin varnish 12 that is suitable for impregnating the inside of the substrate 14 and the amount of resin adhering to the substrate 14 is adjusted to a suitable viscosity is supplied to the substrate liquid level portion A. Can be replaced by the conventional impregnation tank 1
Compared with the case where the resin varnish 12 is supplied from the lower part of the base material 0, the resin varnish 12 in the portion A between the liquid surfaces of the base material has a higher viscosity due to the evaporation of the solvent component, or the air has floated in the liquid and the impregnation property has been reduced. The amount of the resin varnish 12 decreases, and the components are close to the resin varnish 12 which is suitable for impregnating the inside of the base material 14 and the amount of the resin adhering to the base material 14 is adjusted to a suitable viscosity, and is continuously impregnated. However, a prepreg which does not easily generate an unimpregnated portion and has an excellent appearance can be obtained.

The amount of the resin varnish 12 to be supplied to the portion A between the liquid surfaces of the base material is such that the resin varnish 12 of the portion A between the liquid surfaces of the base material among the resin varnish 12 in the impregnation bath 10 It is preferable to supply the resin varnish 12 so that the difference in viscosity of the resin varnish 12 in the portion B of the varnish 12 excluding the portion A between the liquid surfaces of the base material is 0 to 150 centipoise. If the difference in viscosity exceeds 150 centipoise, an unimpregnated portion may be generated or the appearance may be deteriorated.

Although not shown, the resin varnish 12 in the resin receiving tank 13 also covers the resin varnish 12 in the portion B of the resin varnish 12 in the impregnation tank 10 except for the portion A between the liquid surfaces of the base material.
May be provided to supply the resin varnish 12. Alternatively, the amount of the resin varnish 12 impregnated with the resin varnish 12 may be adjusted by drawing out the base material 14 impregnated with the resin varnish 12 from the upper part of the impregnation tank 10 and squeezing the base material between rolls.

The method of the present invention is not limited to the method of adjusting the viscosity by replenishing the solvent 15 while analyzing the viscosity of the resin varnish 12 in the resin receiving tank 13. However, the resin varnish 12 is supplied to the portion A between the liquid surfaces of the base material, and the resin varnish 12
In order to replace the resin varnish, the resin varnish 12 in which air floats in the liquid and the impregnation property is reduced is reduced as compared with the case where the resin varnish is supplied from the lower part of the conventional impregnation tank 10, and the resin varnish in the portion A between the liquid surfaces of the base material is reduced. 12 and the resin varnish 12 in the portion B of the resin varnish 12 in the impregnation tank 10 except for the portion A between the liquid surfaces of the base material, the viscosity difference between the resin varnish 12 and the resin varnish 12 becomes small. The effect of obtaining a prepreg which is difficult and excellent in appearance is obtained.

The resin impregnating method according to the second embodiment of the present invention, as shown in FIGS. 3 and 4, includes an impregnating roll 11 driven inside thereof, and an impregnating tank 10 having an open upper portion.
The resin varnish 12 is filled with the resin varnish 12 until the impregnation roll 11 is sufficiently immersed, and the resin varnish 12 is filled with the resin varnish 12 under the impregnation tank 10. Impregnation tank 1 with material 14
After being supplied from the upper portion of the impregnating tank 10 and continuously penetrating and submerging in the resin varnish 12, the direction is changed by winding it around the impregnating roll 11, and then the base material 14 is pulled out from the upper portion of the impregnating tank 10 to perform impregnation. Do.

The impregnating device is provided with a portion A between the liquid surfaces of the base material.
Inside, the resin varnish 12 flows in the width direction of the base material 14.
Is provided in the impregnation tank 10, and the resin varnish 12 of the resin receiving tank 13 whose viscosity has been adjusted is pressurized and blown out from the blow-out port 22 by a pump, whereby a portion A between the liquid surfaces of the base material is discharged. Is supplied with a resin varnish 12.

As described above, since the resin varnish 12 is supplied to the portion A between the liquid surfaces of the base material to be replaced,
Compared to the case of supplying from the lower part of the conventional impregnation tank 10,
The resin varnish 12 in the portion A between the liquid surfaces of the base material is reduced in the amount of the resin varnish 12 in which the viscosity is increased due to evaporation of the solvent component and the air is suspended in the liquid and the impregnating property is reduced. The components are close to the resin varnish 12 that is suitable for impregnating up to the resin varnish 12 and the amount of the resin adhering to the base material 14 is also adjusted to a suitable viscosity. In addition, a prepreg having an excellent appearance can be obtained.

The resin varnish 12 blown out from the blowout port 22 is not limited to the resin varnish 12 in the resin receiving tank 13, and the resin varnish 12 in the impregnating tank 10 in which the solvent component hardly evaporates is used. Part B excluding the intervening part A
The resin varnish 12 may be sucked and blown out from the outlet 22. Also in this case, the resin varnish 12 in the portion A between the liquid surfaces of the base material and the resin varnish 1 in the impregnation tank 10 are different from the case where the resin varnish is supplied from the lower part of the conventional impregnation tank 10.
Resin varnish 1 of portion B of portion 2 excluding portion A between base liquid levels
The effect of obtaining a prepreg having an excellent appearance is obtained, since the difference in viscosity from that of No. 2 is reduced, and even if the material is continuously impregnated, an unimpregnated portion hardly occurs.

As the base material used in the present invention, woven fabric, non-woven fabric, paper and the like of inorganic fibers such as glass, organic fibers such as polyester, polyamide, polyacryl and polyimide, and natural fibers such as cotton can be used. it can. Note that the use of a glass fiber woven fabric (glass cloth) is preferable because the resulting laminate has excellent heat resistance and moisture resistance.

The resin varnish used in the present invention may be, for example, an epoxy resin, a phenol resin, a polyimide resin, an unsaturated polyester resin, a polyphenylene ether resin, or the like, alone, modified, or mixed. All curable resin compositions can be used.

The resin varnish contains a thermosetting resin and a solvent as essential components, and may contain a curing agent, a curing accelerator, an inorganic filler and the like for the thermosetting resin as required. Note that a thermosetting resin having a low self-curing property, such as an epoxy resin, must also contain a curing agent for curing the resin.

As the solvent contained in the resin varnish, N,
Amides such as N-dimethylformamide, ethers such as ethylene glycol monomethyl ether, acetone,
Examples include ketones such as methyl ethyl ketone, alcohols such as methanol and ethanol, and aromatic hydrocarbons such as benzene and toluene. In the case of at least one solvent selected from the group consisting of methanol, ethanol, methyl ethyl ketone, acetone, benzene, and toluene, the amount of the solvent remaining in the obtained prepreg is reduced, which is preferable.

When the thermosetting resin is an epoxy resin, the balance between the electrical properties and the adhesiveness is good, which is preferable. As the epoxy resin contained in the epoxy resin-based resin varnish, for example, bisphenol A type epoxy resin,
Bisphenol F epoxy resin, bisphenol S epoxy resin, phenol novolak epoxy resin,
Bisphenol A novolak type epoxy resin, bisphenol F novolak type epoxy resin, cresol novolak type epoxy resin, diaminodiphenylmethane type epoxy resin, and flame retardant by partially halogenating hydrogen atoms in these epoxy resin structures Epoxy resins and the like can be mentioned. Examples of the curing agent contained in the epoxy resin-based resin varnish include amide-based curing agents such as dicyandiamide and aliphatic polyamide, amine-based curing agents such as ammonia, triethylamine and diethylamine, phenol novolak resin, and cresol novolak. Resins, phenolic curing agents such as p-xylene-novolak resin, acid anhydrides, and the like.

Examples of the inorganic filler that can be contained in the resin varnish include inorganic powder fillers such as silica, calcium carbonate, aluminum hydroxide, and talc; and glass fibers, pulp fibers, synthetic fibers, and ceramic fibers. Fibrous fillers.

After impregnating the substrate with the resin varnish, it is dried to obtain a prepreg. The conditions for drying are not particularly limited, and the drying is performed under the condition that the used solvent evaporates or the used thermosetting resin is semi-cured.

The resin content of the prepreg after drying is 40 to 70 parts by weight per 100 parts by weight of the prepreg.
It is preferred that the amount be parts by weight. If the amount is less than 40 parts by weight, air bubbles may remain in the obtained laminate, and the electrical characteristics may deteriorate. If the amount exceeds 70 parts by weight, the thickness of the obtained laminate may vary greatly. There is.

[0034]

【Example】

(Example 1) As a primary varnish before viscosity adjustment, a primary varnish containing the following two types of epoxy resins, a curing agent, a curing accelerator and a solvent was used. -Epoxy resin 1: 94 parts by weight of a tetrabromobisphenol A type epoxy resin having an epoxy equivalent of 500 [YDB-500, manufactured by Toto Kasei Co., Ltd.] as a solid content-Epoxy resin 2: Cresol having an epoxy equivalent of 220 13 parts by weight of novolak type epoxy resin [YDCN-220, manufactured by Toto Kasei Co., Ltd.] as a solid content.-Curing agent: 2.8 parts by weight of dicyandiamide-Curing accelerator: 0 of 2-ethyl-4-methylimidazole Solvent: 25 parts by weight of N, N-dimethylformamide.

A glass cloth having a thickness of 0.19 mm [manufactured by Nitto Boseki Co., Ltd., product name: 18W] was used as a base material.

In addition, as the impregnating device, a pipe having an opening for supplying a resin varnish is provided between the liquid surfaces of the base material, and a resin varnish whose viscosity has been adjusted with a solvent is supplied from the opening. And, using an impregnating device formed so that the same viscosity adjusted resin varnish is also supplied to the portion of the impregnation tank except for the portion between the liquid surfaces of the base material, the resin varnish into the impregnation tank from both. Supply and fill, while the substrate is continuously infiltrated into the resin varnish and submerged in the resin varnish, the substrate is impregnated with the resin varnish by the method of continuous drawing and impregnation, then squeezed by being sandwiched between rolls and impregnated The amount of the resin varnish thus prepared was adjusted, and then heated and dried at a maximum temperature of 180 ° C. to prepare a prepreg having a dried resin amount of 52% by weight.

The resin varnish filled in the impregnation tank at the start and the resin varnish supplied after adjusting the viscosity were prepared by adding methyl ethyl ketone to the primary varnish or adding methyl ethyl ketone to the overflowed resin varnish. The viscosity was adjusted to 300 centipoise before use.

(Example 2) As an impregnating device, an opening is provided at the upper part, and in the portion between the liquid surfaces of the base material, an outlet for blowing a resin varnish so as to flow in the width direction of the base material is provided in the impregnation tank. An impregnating device formed so that the resin varnish whose viscosity has been adjusted with a solvent is blown out from the mouth and supplied, and the resin varnish whose viscosity has been adjusted is also supplied to a portion of the impregnation tank except for the portion between the liquid surfaces of the base material. A prepreg was obtained in the same manner as in Example 1 except that the prepreg was supplied from both.

(Example 3) As an impregnating device, a resin varnish whose viscosity was adjusted with a solvent was supplied to a portion of the impregnation tank except for the portion between the liquid surfaces of the substrate, and the base liquid was used. An outlet for blowing resin varnish is provided in the impregnation tank so that the resin varnish flows in the width direction of the base material in the inter-surface portion, and a portion of the resin varnish in the impregnation bath except the inter-substrate liquid surface portion is provided from the outlet. A prepreg was obtained in the same manner as in Example 1, except that an impregnation device formed so as to suck and blow out varnish was used.

(Comparative Example 1) As an impregnating apparatus, an impregnating apparatus was used in which the upper part was an open system and a resin varnish whose viscosity had been adjusted with a solvent was supplied to a part of the impregnation tank except for a part between liquid surfaces of the base material. Except for this, a prepreg was obtained in the same manner as in Example 1.

(Evaluation and Results) Examples 1 to 3 and Comparative Example 1
Impregnated continuously for 1 hour by the method described above, and after 5 minutes, 30 minutes,
After 0 minute, the viscosity was evaluated by sampling the resin varnish in the portion between the liquid surfaces of the base material and the resin varnish in the portion excluding the portion between the liquid surfaces of the base material in the impregnation tank. The prepregs obtained after 5 minutes and 60 minutes were evaluated for impregnation and appearance.

The viscosity of the resin varnish was measured at 25 ° C. using an E-type viscometer. For impregnation, prepreg is 10 × 10
cm, then heat it by suspending it in an electric furnace at 163 ° C. for 15 minutes and then cool it. If there is no part where resin has not penetrated,
And those having a portion where the resin did not penetrate were evaluated as x. The appearance was visually evaluated for the presence or absence of a portion where the resin adhesion amount was large or a portion where the appearance was reduced due to the occurrence of a portion with a small amount of resin adhesion. X.

The results are shown in Table 1. In Examples 1 to 3, the viscosity of the resin varnish in the portion between the liquid surfaces of the base material and the resin varnish in the portion excluding the portion between the liquid surfaces of the base material were different from those in Comparative Example 1. Was small, and the viscosity of the resin varnish in the portion between the liquid surfaces of the base material was confirmed to be little different from the viscosity at the start of the impregnation even after continuous impregnation. Further, it was confirmed that Examples 1 to 3 were superior to Comparative Example 1 in the impregnating property and appearance of the obtained prepreg.

[0044]

[Table 1]

[0045]

According to the resin impregnating method of the present invention, the method of supplying the resin varnish to the impregnation tank is performed by the method comprising the steps of: ), The resin varnish is supplied, so that the resin varnish at the liquid surface portion of the base material can be replaced, and the solvent component evaporates to increase the viscosity or the air floats in the liquid to improve the impregnation. The reduced resin varnish decreases from the portion between the liquid surfaces of the base material, and the components become closer to the resin varnish and the like in the portion of the resin varnish in the impregnation tank except the portion between the liquid surfaces of the base material. Therefore, according to the resin impregnation method according to the present invention, a prepreg excellent in appearance and having less impregnated portions even when continuously impregnated is obtained.

[Brief description of the drawings]

FIG. 1 is a partially cutaway front view for explaining a first embodiment of a resin impregnation method according to the present invention.

FIG. 2 is a partially cutaway side view for explaining the first embodiment of the resin impregnation method according to the present invention.

FIG. 3 is a partially broken front view illustrating a second embodiment of the resin impregnation method according to the present invention.

FIG. 4 is a partially cutaway side view illustrating a resin impregnation method according to a second embodiment of the present invention.

FIG. 5 is a partially cutaway side view illustrating a conventional resin impregnation method.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 10 Impregnation tank 11 Impregnation roll 12 Resin varnish 13 Resin receiving tank 14 Substrate 15 Solvent 20 Pipe 21 Opening 22 Outlet A Section between substrate liquid levels (surrounded by liquid level of base material and resin varnish sinking into resin varnish) Part)

Claims (5)

[Claims] 1. A resin varnish containing a solvent is supplied to and filled in an impregnation tank having an open system at an upper part, and a base material is continuously penetrated into the resin varnish and continuously drawn out while being immersed in the resin varnish. In the resin impregnation method of impregnating the resin varnish, the method of supplying the resin varnish is a method of supplying the resin varnish to a portion of the substrate immersed in the resin varnish and a portion surrounded by the liquid surface of the resin varnish. Resin impregnation method. 2. A method of supplying a resin varnish to a portion of a substrate sinking in a resin varnish and a portion surrounded by a liquid level of the resin varnish, wherein the method comprises supplying the resin varnish to a portion of the substrate sinking in the resin varnish. Pipe with an opening in the
The resin impregnation method according to claim 1, wherein the resin varnish is supplied by flowing out from the opening. 3. A method of supplying a resin varnish to a portion of a resin varnish submerged by a base material and a liquid surface of a resin varnish. The resin impregnating method according to claim 1, wherein a blow-out port for blowing the resin varnish is provided in the impregnation tank so as to flow in the width direction of the base material within the portion, and the resin varnish is supplied by blowing the resin varnish. . 4. A resin varnish in a portion of the resin varnish in the impregnation tank that sinks into the resin varnish and a portion of the resin varnish surrounded by the liquid surface of the resin varnish and a portion of the resin varnish in the impregnation tank that sinks in the resin varnish. The difference in viscosity of the resin varnish in the portion excluding the portion surrounded by the liquid surface of the base material and the resin varnish is 0 to 1
4. The resin varnish is supplied to a portion of the resin varnish submerged in the resin varnish and a portion surrounded by the liquid surface of the resin varnish so as to have a volume of 50 centipoise.
The resin impregnation method according to any one of the above. 5. The method according to claim 1, wherein the solvent contained in the resin varnish contains at least one solvent selected from the group consisting of methanol, ethanol, methyl ethyl ketone, acetone, benzene and toluene. The resin impregnation method according to claim 4.