JP2009214036A - Gravure coater - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a gravure coater having an excellent maintenance performance, which does not befoul it by a splashing of a coating material from the end part of a gravure roll. <P>SOLUTION: The gravure coater 10 includes a gravure roll 21 and a doctor blade 23, allows the coating material 18 to adhere to the surface of a large-diameter part 21a formed on the gravure roll 21, and coats a thin film 50 with the coating material 18 by the contact of the surface of the large-diameter part 21a with the thin film 50, and is characterized in that a liquid reserving groove 21e going the circuit of the outer periphery of the gravure roll 21 is formed between the end part of the large-diameter part 21a and the doctor blade 23. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a technique for preventing a coating material from being scattered from a gravure roll and soiling equipment and workpieces when a coating material is applied to a sheet material using a gravure coating apparatus.

  In recent years, a secondary battery is used as a power source for many electronic devices, and the use of a secondary battery is also being studied as a power source for vehicles. Along with this, demands for secondary batteries with larger capacity, higher output, and lighter weight have also increased. Against this background, various secondary batteries such as lithium ion secondary batteries and nickel hydride secondary batteries are being developed.

Such a secondary battery may be used as an electrode plate of a battery by applying an active material to a metal core (foil). There is also a case in which a protective film made of a porous insulating film is further formed on the surface of the coated part coated with the active material.
Various methods for applying an active material or a protective film to such a core material have been proposed. In order to apply a coating material while maintaining the uniformity of the thin film thickness, a gravure coating apparatus is used. A method of using is being studied.
The coating material is applied to the core material by a gravure coating device, and the coated portion is cut after drying / compression treatment to produce a secondary battery electrode plate having a desired size.

By the way, when applying a coating material to sheets, such as a core material, using such a gravure coating apparatus, there existed a problem that a coating material scattered from the edge part of a gravure roll.
Since the coating material is attached to the gravure roll and the gravure roll is rotated at high speed, centrifugal force acts on the coating material attached to the surface of the gravure roll. The surface of the gravure roll comes into contact with the sheet to transfer the coating material and apply the coating material to the sheet. The coating material adhering to the surface of the gravure roll is transferred to the sheet after the excess part is scraped off by a doctor blade. Therefore, a little coating material remains on the surface of the gravure roll after being scraped off by the doctor blade.
However, the coating material adhering to the portion not in contact with the sheet is scattered under the influence of centrifugal force. The scattered coating material is not preferable because it adheres to the sheet or soils the apparatus.
If the coating material adheres to the sheet, there is a possibility that a defect may occur. If the apparatus is soiled, cleaning is required during maintenance, and the extension of the maintenance time leads to a decrease in productivity.

Therefore, Patent Documents 1 and 2 disclose a technique for preventing such scattering.
Patent Document 1 discloses a technique in which a cover is provided in a position corresponding to both end portions of a doctor blade in a coating roll, which is a gravure roll, in a non-rotating state as a coating device.
The U-shaped cover is provided at a position corresponding to both ends of the doctor blade in the coating roll, and is fixed so as not to rotate. By this U-shaped cover, the coating material adhering to the application roll is scraped off. Further, since the end portion of the doctor blade is also in contact with the U-shaped cover, the coating material escaping outward from the end of the doctor blade falls down along the U-shaped cover without being scattered.

The U-shaped cover is operated while immersed in the coating material. Since the gravure roll is also operated in a state immersed in the coating material, there is a possibility that the coating material may enter between the U-shaped cover and the gravure roll. For this reason, disposing the mini doctor blade inside the U-shaped cover prevents the coating material from entering between the U-shaped cover and the gravure roll.
Thus, by providing the U-shaped cover at positions corresponding to both ends of the doctor blade, it is possible to prevent the coating material from scattering.

Patent Document 2 discloses a technique for preventing scattering by providing a sleeve having a bearing at the end of a gravure roll as a coating apparatus. The end of the doctor blade comes into contact with a sleeve provided at the end of the gravure roll, and the sleeve is less likely to rotate together with the gravure roll by incorporating a bearing. Therefore, scattering of the coating material due to centrifugal force is less likely to occur, and the coating material is likely to fall down.
In this way, scattering of the coating material can be prevented.

JP-A-5-220430 JP-A-6-269716

However, the techniques of Patent Document 1 and Patent Document 2 are considered to have the following problems.
When the method of Patent Document 1 is used, it is inevitable that the coating material enters between the U-shaped cover and the gravure roll.
For this reason, it is considered that periodic cleaning is necessary after removing the U-shaped cover, and there is a problem that maintenance becomes troublesome.
Moreover, since the scraper is used for the U-shaped cover, the coating material eventually moves toward the end of the scraper, and the coating material may be scattered at the end of the gravure roll.

When using the method of patent document 2, it is necessary to equip the gravure roll itself with a bearing. In view of the configuration of the gravure coating apparatus, the gravure roll needs to be partially immersed in the coating material. It is not preferable that this coating material enters the bearing. In Patent Document 2, a seal material is used. However, if the seal is not perfect, there is a possibility that the coating material enters the bearing.
Depending on the coating material, not only ink but also particles such as alumina may be used. When forming a protective film for an electrode of a secondary battery, insulating particles are often mixed. Therefore, when the coating material containing particles enters the bearing, there is a problem that the bearing is deteriorated by the coating material. Further, if a binder liquid or the like is used for the coating material, it becomes unfavorable because it becomes a resistance to rotation of the bearing.

  That is, as shown in Patent Literature 1 and Patent Literature 2, it is considered that it is not preferable from the viewpoint of maintenance to provide a non-rotating portion on the gravure roll side to complicate the mechanism.

  Then, in order to solve such a subject, this invention aims at providing the gravure coating apparatus excellent in maintainability, without polluting an apparatus by scattering of the coating material from the edge part of a gravure roll. .

In order to achieve the object, the gravure coating apparatus according to the present invention has the following characteristics.
(1) A gravure comprising a gravure roll and a doctor blade, applying a coating material to a coating surface formed on the gravure roll, and applying the coating material to the sheet by bringing the coating surface into contact with the sheet In coating equipment,
A liquid storage groove that makes a round around the outer periphery of the gravure roll is formed between an end of the coating surface and an end of the doctor blade.

(2) In the gravure coating apparatus according to (1),
It is provided with the cover which covers at least one part of the circumferential direction of the said liquid accumulation groove | channel provided in the said gravure roll.

With the gravure coating apparatus according to the present invention having such characteristics, the following actions and effects can be obtained.
First, the invention described in (1) includes a gravure roll and a doctor blade, and a coating material is attached to a coating surface formed on the gravure roll, and the coating surface and the sheet are brought into contact with each other. In a gravure coating apparatus for applying a material, a liquid collecting groove that makes one round of the outer periphery of a gravure roll is formed between an end of a coating surface and an end of a doctor blade.

Most of the coating material adhering to the coated surface of the gravure roll is scraped off by a doctor blade. The coating material scraped off by the doctor blade includes those that fall downward and those that move toward the end of the doctor blade, that is, in the axial direction of the gravure roll. The coating material moving to the end of the doctor blade is collected in a liquid pool groove provided on the outer periphery of the gravure roll.
The coating material collected in the pool groove is blown away by centrifugal force at the position of the pool groove, but the end of the doctor blade is outside the pool groove, so most of the scattered coating material Adheres to the surface of the doctor blade. That is, the doctor blade itself serves as a cover for preventing the coating liquid from scattering.
In this way, by adopting a simple structure in which a liquid accumulation groove that goes around the outer periphery of the gravure roll is formed between the end of the coating surface and the end of the doctor blade, the coating liquid is prevented from being scattered. It becomes possible.

  The liquid pool groove that goes around the outer periphery of the gravure roll is formed by processing the gravure roll. Since it is a simple structure in which a recess is provided on the outer periphery of the gravure roll as a liquid pool groove, it is excellent in maintainability. Therefore, it is possible to provide a gravure coating apparatus that suppresses scattering of the coating material from the end of the gravure roll and is excellent in maintainability.

Moreover, the invention described in (2) is a gravure coating apparatus described in (1), which includes a cover that covers at least a part of the circumferential direction of the liquid collecting groove provided in the gravure roll.
The coating liquid collected in the liquid pool groove is scattered in the circumferential direction by the rotation of the gravure roll. The scattering coating liquid adheres to the lower surface side of the doctor blade and falls, but it is conceivable that a part of the coating liquid also scatters after the doctor blade. Therefore, by providing a cover that covers the circumferential direction of the liquid pool groove, it is possible to prevent scattering more reliably.
And if the cover which covers the circumferential direction of a station reservoir groove is combined with the composition of (1), if it covers the diameter direction outside of a fluid reservoir groove in the rotation back side of a gravure roll rather than a doctor blade. good. That is, since it is only necessary to cover a limited narrow area, the apparatus can be configured simply.

Next, the gravure coating apparatus of the present invention will be described with reference to the drawings.
In FIG. 1, the front view of the gravure coating apparatus 10 of this embodiment is shown. In FIG. 2, the side view of the gravure coating apparatus 10 is shown.
The gravure coating apparatus 10 is an apparatus for applying the coating material 18 to the thin film 50 formed in a sheet shape.
The thin film 50 is a base material used for a lithium ion battery, and is a copper foil or an aluminum foil having a thickness of about several tens of μm. The length is about several thousand meters and is wound and stored in a roll shape. Therefore, the gravure coating apparatus 10 includes an uncoiler and a coiler (not shown).
The coating material 18 to be coated is a liquid having a viscosity of about several Pas. The coating material 18 is applied on the thin film 50 with a thickness of about several μm, and the coating film is formed with a constant thickness. This coating film is formed as a protective film on the surface of an active material used in a secondary battery, or is applied under the active material, and an active material layer is formed thereon.

The gravure coating apparatus 10 includes a support housing 12 mounted on a base 11, an arm 13 supported by the support housing 12, and a coating mechanism section 20 disposed on the support mechanism 30.
The thin film 50 is passed through a plurality of rollers, and is also passed between the gravure roll 21 provided in the coating mechanism unit 20 and the pressing roller 14 provided in the arm 13. As a result, the thin film 50 is in a state where the tension is applied to the gravure roll 21 side by the pressing roller 14.
A post-process of the gravure coating apparatus 10 includes a drying furnace (not shown). After the protective film or the like is formed on the surface of the thin film 50 by the gravure coating apparatus 10, the film is dried in a drying furnace in a subsequent process and finally wound on a bobbin (not shown).

The gravure roll 21 is connected to a drive motor 35 via a coupling 36 as shown in FIG. The drive motor 35 is preferably a motor capable of controlling rotation, such as a servo motor.
The gravure roll 21 receives power from the drive motor 35 and rotates. Then, the gravure roll 21 coats the coating material 18 on the surface of the thin film 50 being sent.
In FIG. 3, the side view of the coating mechanism part 20 is shown. FIG. 4 is a perspective view of the coating mechanism unit 20.
The coating mechanism unit 20 includes a gravure roll 21, a doctor blade 23, and a nozzle block 25.
The gravure roll 21 is provided with a large diameter portion 21a and a small diameter portion 21b. The surface of the large-diameter portion 21a is provided with irregularities so that the coating film 50a can be formed on the thin film 50 as the coating surface.

The doctor blade 23 is attached to the gravure coating apparatus 10 via the gripping member 22 so as to contact the surface of the large diameter portion 21a of the gravure roll 21. The doctor blade 23 can be pressed against the gravure roll 21 by applying a certain force by a cylinder or the like, and the coating material 18 attached to the surface of the large diameter portion 21a can be scraped off by the doctor blade 23.
The doctor blade 23 is a resin blade, and wears when the doctor blade 23 comes into contact with the gravure roll 21 and rotates. If the metal powder is mixed into the coating material 18, the performance of the secondary battery may be adversely affected. is there. For this reason, the gravure roll 21 side is made of metal, whereas the doctor blade 23 side is made of resin, and the doctor blade 23 has a lower hardness than the gravure roll 21 material, and the doctor blade 23 side is consumed. Has been.
The material of the doctor blade 23 is not particularly limited as long as the material has low conductivity or exhibits insulating properties.

A supply flow path 25 a is formed in the nozzle block 25. Although not shown, the supply channel 25a is an octopus leg that branches in the middle from the supply side so that the coating material 18 is evenly supplied to the supply groove 25b formed at the tip of the supply channel 25a. It has a structure. The nozzle block 25 can be disassembled so that the supply flow path 25a can be easily accessed, and consideration is given to facilitate cleaning maintenance.
The supply channel 25a and the supply groove 25b are connected, and the coating material 18 is supplied.
The supply groove 25b is formed at an equal distance from the outer periphery of the gravure roll 21 with an appropriate gap, and the distance between the surface of the large diameter portion 21a and the surface of the supply groove 25b is designed to be constant. Yes.
A gap between the surface of the large-diameter portion 21 a of the gravure roll 21 and the surface of the supply groove 25 b is a gap that can hold the coating material 18.

The liquid splash prevention plate 26 and the dam plate 27 are liquid holding members, which are formed by bending a stainless steel plate.
The liquid splash prevention plate 26 is integrally formed with the side cover 26 b so as to cover the upper side of the gravure roll 21 while being attached to the upper surface of the nozzle block 25. However, as shown in FIG. 3, the side cover 26 b is provided at both ends of the liquid splash prevention plate 26 because the cutout 26 a for allowing the thin film 50 to pass therethrough is provided. The notch 26a has a shape such that a part of the wall surface portion 26c remains.
The dam plate 27 is a substantially L-shaped member attached to the upper surface of the nozzle block 25.

As a method of joining the nozzle block 25, the liquid splash prevention plate 26 and the dam plate 27, a method of fixing with a bolt (not shown) is adopted. This is because the viscosity of the coating material 18 is relatively high, so that it is not necessary to worry about leakage.
A liquid pan 28 is provided below the nozzle block 25 and receives the overflowing coating material 18 from the liquid splash prevention plate 26 and the dam plate 27.
FIG. 5 shows a schematic plan view of the gravure roll 21.
In addition to the large diameter portion 21a and the small diameter portion 21b, the gravure roll 21 includes an outer peripheral groove 21c, a first plate support portion 21d, a liquid pool groove 21e, and a second plate support portion 21f.
The width of the nozzle block 25 is formed to be slightly wider than the width of the large diameter portion 21a. Accordingly, the end of the nozzle block 25 is located in the outer peripheral groove 21c.
Although the large-diameter portion 21a in FIG. 5 is shaded, the coating material 18 adheres to this portion and becomes a portion where the coating material 18 is applied to the thin film 50. It is basically undesirable for the coating material 18 to adhere to other portions.

The width of the large diameter portion 21a is designed to be narrower than the width of the thin film 50. This is because a coated part and an uncoated part are formed on the thin film 50. Therefore, the end of the thin film 50 is located in the outer peripheral groove 21c. The first plate support portion 21d and the second plate support portion 21f have the same diameter as the large diameter portion 21a, and the liquid pool groove 21e has a smaller diameter than the first plate support portion 21d and the second plate support portion 21f. Is formed.
A side cover 26b of the liquid splash prevention plate 26 is disposed above the liquid reservoir groove 21e.
The doctor blade 23 is set to have such a width that the end portion thereof covers the second plate support portion 21f.

Since the gravure coating apparatus 10 of this embodiment is the said structure, there exists an effect | action and effect which are demonstrated below.
First, the first effect is that the coating liquid can be prevented from scattering.
The gravure coating apparatus 10 of the present embodiment includes a gravure roll 21 and a doctor blade 23, and attaches a coating material 18 to the surface of the large diameter portion 21a formed on the gravure roll 21, so that the surface of the large diameter portion 21a In the gravure coating apparatus 10 that applies the coating material 18 to the thin film 50 by bringing the thin film 50 into contact, the outer periphery of the gravure roll 21 is placed between the end of the large diameter portion 21 a and the end of the doctor blade 23. A liquid pool groove 21e that makes a round is formed.

In FIG. 6, the schematic diagram showing a mode that the coating material flies around the gravure roll 21 is shown.
By the rotation of the gravure roll 21, the coating material 18 collected in the liquid pool groove 21e is scattered in the direction shown by the scattering locus 18a by centrifugal force.
Since the coating material 18 is supplied from the nozzle block 25 as shown in FIG. 5, it basically adheres only to the surface portion of the large-diameter portion 21a. A semicircular scraper member (not shown) is provided in the outer circumferential groove 21 c so as not to rotate together with the gravure roll 21. For this reason, the coating material 18 is not supplied to the outer peripheral groove 21c portion.
However, since the coating material 18 is scraped off by the doctor blade 23 as shown in FIG. 3, the coating material 18 is scraped off and adhered to the back side of the doctor blade 23. Some of the coating material 18 attached in this way falls to the liquid pan 28 as it is, and some of the coating material 18 moves in the lateral direction, that is, the outside of the gravure roll 21 in the axial direction.

The coating material 18 that moves to the outside in the axial direction of the gravure roll 21 will eventually move to the end of the doctor blade 23 unless it is provided with the liquid collecting groove 21e, and will be scattered there. However, since the liquid pool groove 21e is provided, the coating material 18 attached to the doctor blade 23 is collected inside the liquid pool groove 21e. Since the coating material 18 is collected by the liquid pool groove 21e, it does not move to the second plate support portion 21f side.
Since the coating material 18 collected in the liquid reservoir groove 21e becomes heavier when the coating material 18 is collected, the coating material 18 is easily scattered by the centrifugal force acting on the gravure roll 21. As a result, it scatters in the direction of the scattering locus 18a.

However, at the end of the scattering locus 18a, a doctor blade 23 having an end formed outside the liquid pool groove 21e and a liquid splash prevention plate 26 arranged so as to cover the circumferential direction of the liquid pool groove 21e are provided. A side cover 26b is disposed.
For this reason, even if the coating material 18 is scattered, it adheres to the back side of the doctor blade 23 and the side cover 26b and can be collected.
For this reason, the coating material 18 is scattered on the thin film 50 and other parts of the gravure coating apparatus 10, thereby preventing a failure or contaminating the other parts of the gravure coating apparatus 10. can do.
In particular, by providing the side cover 26b that covers the circumferential direction of the liquid collecting groove 21e provided in the gravure roll 21, scattering of the coating material 18 can be further prevented.

A second effect is that maintenance is high.
If a complicated structure as shown in Patent Document 2 is used, cleaning is difficult when the coating material 18 enters the inside.
However, since the gravure roll 21 has a simple structure in which the liquid collecting groove 21e is provided and the side cover 26b extended from the liquid splash prevention plate 26 is provided, cleaning is relatively easy and can be completed in a short time.
In addition, it can be considered as a merit that maintenance only requires cleaning. If scrapers or bearings are used, they must be replaced each time they are consumed. In particular, when hard particles such as alumina are mixed in the coating material 18, since the wear becomes intense, it takes time for maintenance. However, if it is a simple structure like this embodiment, since there is no sliding part other than the doctor blade 23, it is only necessary to replace the doctor blade 23.

The doctor blade 23 of this embodiment uses a resin because the thin film 50 is used as a material for a secondary battery. Therefore, replacement is required relatively frequently. For this reason, the maintenance as a measure for preventing the coating material 18 from scattering is unnecessary except for cleaning.
Note that the reason why the end portion of the doctor blade 23 is extended to the second plate support portion 21f of the gravure roll 21 is also because the doctor blade 23 is made of resin.
Since the doctor blade 23 is made of resin and has low rigidity, it is difficult to obtain straightness. Therefore, when the end of the doctor blade 23 is floating in the air, the contact pressure at the center of the doctor blade 23 tends to decrease. In order to prevent such a situation, the end portion of the doctor blade 23 is configured to be supported by the second plate support portion 21f.

Although the invention has been described according to the present embodiment, the invention is not limited to the embodiment, and by appropriately changing a part of the configuration without departing from the spirit of the invention. It can also be implemented.
For example, it does not prevent changing the configuration of the coating mechanism unit 20 such as the shape of the gravure roll 21. Further, the shape of the liquid splash preventing plate 26 does not prevent the side cover 26 b from extending below the nozzle block 25 and increasing the portion covering the periphery of the gravure roll 21.
Although the material of the doctor blade 23 is also mentioned, the present invention can be applied even when the doctor blade 23 using a material other than resin is used.

It is a front view of the gravure coating apparatus of this embodiment. It is a side view of the gravure coating apparatus of this embodiment. It is side surface sectional drawing of the coating mechanism part of this embodiment. It is a perspective view of the coating mechanism part of this embodiment. It is a plane schematic diagram of the gravure roll of this embodiment. It is the schematic diagram showing the locus | trajectory that the coating material scatters around the gravure roll of this embodiment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Gravure coating apparatus 20 Coating mechanism part 21 Gravure roll 21a Large diameter part 21b Small diameter part 21c Outer peripheral groove 21d 1st board support part 21e Liquid accumulation groove 21f 2nd board support part 22 Grasp member 23 Doctor blade 25 Fountain type nozzle block 25a Supply channel 25b Supply groove 26 Liquid splash prevention plate 26a Notch 26b Side cover 26c Wall portion 27 Dam plate 27a Inner wall surface 50 Thin film

Claims (2)

A gravure coating apparatus comprising a gravure roll and a doctor blade, applying a coating material to a coating surface formed on the gravure roll, and applying the coating material to the sheet by contacting the coating surface and the sheet In
A gravure coating apparatus is characterized in that a liquid collecting groove is formed around the outer periphery of the gravure roll between an end of the coating surface and an end of the doctor blade. In the gravure coating apparatus according to claim 1,
A gravure coating apparatus comprising: a cover that covers at least a part of a circumferential direction of the liquid collecting groove provided on the gravure roll.

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