JP2009119429A - Thin film coater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a thin film coater attaining uniform coating of a thin film having a film thickness of approximately 50-200 nm. <P>SOLUTION: The thin film coater is provided with a coating roll for coating a surface of a conveyed web-like base material to be coated with a coating film of a coating liquid, and is provided with at least a reverse roll reverse-rotated in an opposite direction to a traveling direction of the base material to be coated while abutting on the surface portion of the coating film coated by the coating roll, removing the excessive coating liquid while leveling the surface of the coating film and making it to the thin film. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a thin film coating apparatus capable of uniformly coating a thin film having a film thickness of, for example, about 50 nm to 200 nm.

  Examples of the coating method for forming a coating film of the coating liquid on the substrate to be coated include a gravure method, a rod coating method, a reverse roll coating method, and a reverse gravure method.

  The coating method according to the gravure method is a method of transferring the coating liquid filled in each cell of the gravure roll onto the substrate to be coated, so that the cell pattern remains on the coating surface. Have. This problem cannot be solved only by improving the leveling property by adjusting the concentration and viscosity of the coating solution, and it is difficult to obtain a uniform coating film and a smooth coating surface. Further, when a thin coating film is applied, it is difficult to obtain a good coated surface because smoothing is difficult.

  In the coating method according to the gravure method, the coating amount is determined by the cell volume of the cells provided in the gravure roll. For example, in coating using a gravure roll having very fine cells of about 250 L / inch, the coating amount when wet is about several μm.

  If the solid content of the coating solution is lowered, even when the coating amount when wet is several μm, the coating amount when dry is smaller than this, and a slightly thin coating film can be obtained. If an excessive solvent is added to the coating solution to lower the coating solution, the coating suitability is deteriorated and the coating state is deteriorated. Incidentally, if the solid content of the coating solution is lowered too much, unevenness due to a difference in the skin and local drying speed will occur.

  Further, the coating method according to the rod coating method is a coating method in which the coating liquid transferred by the coating roll is scraped with a wire bar, and can be applied with a coating device having a simple structure. However, when the viscosity of the coating liquid is high, it is difficult to obtain a thin film, and there is a drawback that vertical stripes along the coating direction are likely to occur.

  In addition, the coating method related to the reverse roll coating method is a method that makes it easy to obtain a smooth coating surface, but has skill in adjustment, the film thickness changes due to subtle changes in viscosity, and the lines are likely to be streaked. However, it has drawbacks such as difficulty in obtaining a thin film.

Furthermore, the coating method according to the reverse gravure method generally has the disadvantages that the coating liquid is easy to swim, the horizontal stage is easy to come out, and the base material to be coated is prone to wrinkles, but the gravure roll has a small diameter. In some cases, a very good coated surface may be obtained. In this case, a small-diameter gravure roll having a diameter of about 20φ to 50φ is used, but a better coating surface can be obtained by using a kiss coating method without a backup roll (see, for example, Patent Document 1). However, this coating method is difficult to obtain a thin film.
Japanese Utility Model Publication No. 2-7663

  The present invention has been made to solve the problems of the related art, and causes a coating defect such as a cell pattern, swimming, streaks, step unevenness, etc. even in a thin film having a film thickness of about 50 nm to 200 nm. The present invention provides a thin film coating apparatus which can be applied with a uniform film thickness.

  In order to achieve the above-described problems, the invention according to claim 1 is a coating for applying a coating film of a coating solution on the surface of a web-like substrate to be conveyed. A roll is provided and reversely rotated in a direction opposite to the traveling direction of the substrate to be coated while abutting against the surface portion of the coating film applied by the coating roll, thereby leveling the surface portion of the coating film. A thin film coating apparatus comprising at least a reverse roll for removing a surplus coating liquid and thinning the coating film.

  Further, the invention according to claim 2 is the thin film coating apparatus according to claim 1, wherein the reverse roll is equipped with a doctor device, and the excess coating liquid removed by the doctor device is removed. A collection pan for collection is arranged.

  Furthermore, the invention described in claim 3 is characterized in that, in the thin film coating apparatus according to claim 1 or 2, the rotation speed of the reverse roll is adjustable.

  Furthermore, the invention according to claim 4 is the thin film coating apparatus according to any one of claims 1 to 3, wherein the reverse roll is in a state in which the distance from the place where the coating film is applied can be adjusted. It is attached by.

  Since this invention is a thing of the above structures, precise coating becomes possible, without being limited to the coating system of a coating film. Therefore, even a thin film of about 50 nm to 200 nm can be applied with a uniform thickness without causing cell patterns, swimming, streaks, step unevenness, and the like.

  FIG. 1 shows a schematic cross-sectional configuration of the thin film coating apparatus of the present invention. This thin film coating apparatus generally includes a coating film coating unit for coating a coating film made of a coating liquid on the substrate 1 to be coated, and a coating applied by the coating film coating unit. It consists of a thin film forming section for removing excess coating liquid while leveling the surface of the film to make the coating film thinner.

  The coating film forming section temporarily supplies a coating liquid pan 6 for storing the coating liquid and a predetermined amount of the coating liquid in the coating liquid pan 6 to the surface portion thereof, and conveys it. The coating roll 2 (gravure coating roll) for transferring to the surface of the substrate 1 to be coated and coating the coating film, and a predetermined amount of coating liquid on the surface portion of the coating roll 2 A coating device that is temporarily supplied to the surface of the coating roll 2 is coated while the doctor device 8 for feeding and the coated substrate 1 being conveyed are sandwiched between the coating roll 2 An impression cylinder 3 for transferring to the surface of the work base 1 is provided.

  On the other hand, the thin film forming unit rotates in the reverse direction in the direction opposite to the traveling direction of the coated substrate 1 while contacting the surface portion of the coating film applied by the coating film forming unit configured as described above. The excess coating liquid is removed while leveling the surface portion of the film, and the reverse roll 4 for making a uniform thin film and the excess coating liquid removed from the surface of the coating film are scraped off from the reverse roll 4 At least a doctor device 7 and a collection pan 5 for collecting and storing the surplus coating liquid scraped off by the doctor device 7 are provided.

In the illustrated thin film forming portion, a discharge port 9 is provided in the recovery pan 5 so that the coating liquid can be recovered and reused. In addition, the coating mechanism in the coating film forming part is shown as a gravure type in the illustrated example, but the coating mechanism in the coating film forming part of the thin film coating apparatus of the present invention is not limited to this. In addition, a coating mechanism related to a coating method such as a rod coating method, a reverse roll coating method, or a reverse gravure method can be arbitrarily selected.

  The number of rotations of the reverse roll 4 that rotates in reverse is adjustable. If the rotation speed of the reverse roll 4 is increased, more coating liquid can be removed from the coating film side, and if the rotation speed is decreased, the removal amount can be reduced. What is necessary is just to adjust the rotation speed of a reverse roll according to the removal amount of the coating liquid required.

  This reverse roll 4 has a movable structure in which the distance from the coating film forming part can be changed, and the distance from the coating film forming part in the coating film forming part can be appropriately adjusted according to the coating liquid to be used. It is attached in the state. When a solvent is added to the coating liquid, there are a solvent that is fast drying and a solvent that is slow depending on the type of the solvent. In the case of fast drying, the coating film forms a film before reaching the reverse roll, so that it becomes impossible to remove the coating liquid necessary for thinning. In order to prevent this from happening, the reverse roll 4 is moved to a position close to the coating film forming section so that a necessary amount of the coating liquid can be removed before the coating film becomes a film.

  Hereinafter, a thin film coating method using the illustrated thin film coating apparatus will be briefly described.

  The coated substrate 1 that has been conveyed moves while being sandwiched between the coating roll 2 (gravure roll) and the impression cylinder 3 of the coating film forming section, and is filled in the cells of the gravure roll 2 between them. For example, a coating solution having a low solid content is transferred to the surface of the substrate 1 to be coated, and a coating film is applied. The coated substrate 1 coated with a coating film having a predetermined film thickness is further conveyed to the thin film forming section. In the thin film forming portion, the reverse roll 4 that rotates reversely is set in contact with the surface portion of the coating film, and the excess coating liquid is removed by the reverse roll 4 to reduce the thickness of the coating film.

  The reverse roll 4 has no backup roll and is a kiss touch. The pressure on the substrate to be coated is covered by the tension of the substrate 1 to be coated. Accordingly, even if there is a curl or the like on the substrate 1 to be coated, the entire surface of the substrate is uniformly contacted, so that it is possible to remove excess coating liquid without unevenness. As a result, the coating film on the substrate 1 to be coated is made into a thin film, and a thin film having a good surface condition and a uniform thickness is obtained.

  As the reverse roll 4, a roll having a smooth surface can be used. However, the surface may be roughened by sandblasting.

  Moreover, the rotation speed of the reverse roll 4 is variable. If the number of rotations is increased, more coating liquid can be removed from the coating film side, and if the number of rotations is decreased, the amount of removal can be reduced.

  Further, as described above, the reverse roll 4 has a movable structure in which the distance from the coating film forming portion can be changed, and the installation position can be adjusted according to the type of coating liquid. Yes.

  Excess coating liquid scraped from the coating film side to the reverse roll side is scraped off by the doctor device 7, collected in the receiving pan 5, and reused.

It is explanatory drawing which shows the general | schematic cross-section structure of the thin film coating apparatus of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 ... Coating substrate 2 ... Coating roll 3 ... Impression drum 4 ... Reverse roll 5 ... Recovery pan 6 ... Coating liquid pan 7 ... Doctor device 8 ... Doctor device 9 ... Discharge port

Claims (4)

  A coating roll for coating a coating film of the coating liquid on the surface of the web-like substrate to be conveyed is provided, and on the surface portion of the coating film coated by this coating roll. Reverse roll for making the coating film thinner by removing the excess coating liquid while smoothing the surface part of the coating film while rotating reversely in the direction opposite to the traveling direction of the coated substrate while abutting And a thin film coating apparatus.   2. The thin film coating device according to claim 1, wherein the reverse roll is equipped with a doctor device, and a collection pan for collecting the excess coating liquid removed by the doctor device is arranged. Engineering equipment.   The thin film coating apparatus according to claim 1, wherein the reverse roll has an adjustable rotation speed.   The thin film coating apparatus according to any one of claims 1 to 3, wherein the reverse roll is attached in a state in which a distance from a portion where the coating film is applied can be adjusted.

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