JP6846569B2 - Coating equipment and coating method - Google Patents

Description

The present invention relates to a coating device and a coating method, for example, a coating device for coating an electrode material, and a coating method.

Conventionally, by rotating the transfer roller while contacting the coating liquid filled in the chamber, the coating liquid is adhered to the outer peripheral surface of the transfer roll, and the adhered coating liquid is transferred to the material to be coated. Gravure coating equipment is known. The transfer roll used in the gravure coating apparatus has a groove formed on the surface of the roll for holding the coating liquid. The gravure coating apparatus has been conventionally used in various fields, for example, for coating an electrode material on a metal foil (see, for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2011-222296

When coating the electrode material, the electrode material is generally a slurry, and the viscosity of the slurry may be relatively high. However, when a coating liquid having a high viscosity is applied to the material to be coated, the coating film may have streaks or uneven coating depending on the groove shape of the transfer roll. Streaks and uneven coating can be eliminated by increasing the rotation speed of the transfer roll, for example, but increasing the rotation speed increases the amount of coating liquid that overflows to the outside of the chamber as the rollers rotate. As a result, the amount of the coating liquid adhering to the transfer roll is reduced, which may cause coating omission.

The present invention has been made in view of the above problems. For example, even when the viscosity of the coating liquid is relatively high, the coating film may have streaks, uneven coating, or omission of coating. It is an object of the present invention to provide a coating apparatus and a coating method having good coating performance by preventing the above.

As a result of diligent studies, the present inventors set the arrangement position of the supply port for supplying the coating liquid to the chamber or the supply amount of the supply port according to the groove shape formed on the outer peripheral surface of the transfer roll. We have found that the problem can be solved and completed the following invention. The gist of the present invention is the following [1] to [13].

[1] A chamber in which the coating liquid is filled, and
A transfer roll that is arranged so as to come into contact with the coating liquid filled in the chamber, adheres the coating liquid to the outer peripheral surface, and is rotated to transfer the coating liquid to the material to be coated.
The chamber is provided with a supply port for supplying the coating liquid.
The supply port has a main supply port and an auxiliary supply port.
The transfer roll has a groove on the outer peripheral surface that is inclined with respect to the rotation direction.
The auxiliary supply port is arranged so as to be offset from the central portion to one end side in the lateral direction of the chamber, and the one end portion extends the groove from below along the rotation direction of the transfer roll. A coating device, which is the end of the groove on the opposite side when viewed from above.
[2] The coating apparatus according to the above [1], wherein the amount of the coating liquid supplied from the supply port in the lateral direction of the chamber is larger on one end side than on the other end side.
[3] The coating device according to the above [1] or [2], wherein the auxiliary supply port is arranged between the central portion and the one end portion.
[4] The said at a position downstream in the rotational direction from a position where the coating liquid is filled in the chamber in contact with the coating liquid, and at an upstream side in the rotational direction from a position where the coating liquid is transferred to the material to be coated. The coating apparatus according to any one of [1] to [3] above, further comprising a blade for scraping the coating liquid adhering to the transfer roller.
[5] The coating apparatus according to any one of the above [1] to [4], wherein the viscosity of the coating liquid is 1700 to 2300 mPa · s.
[6] The amount of the coating liquid supplied from the auxiliary supply port is 0.02 to 0.2 of the amount of the coating liquid supplied from the main supply port according to the above [1] to [5]. The coating apparatus according to any one item.
[7] The main supply port is composed of one or more supply ports, and the supply amount from the auxiliary supply port is smaller than the supply amount of any of the supply ports constituting the main supply port. 6] The coating apparatus according to any one of the items.
[8] The coating device according to any one of the above [1] to [7], wherein the material to be coated is an electrode material for a lithium ion secondary battery.
[9] The coating apparatus according to any one of the above [1] to [8], comprising a circulation line for circulating the coating liquid overflowing from the chamber and supplying the coating liquid from the auxiliary supply port.
[10] A chamber in which the coating liquid is filled, and
A transfer roll that is arranged so as to come into contact with the coating liquid filled in the chamber, adheres the coating liquid to the outer peripheral surface, and is rotated to transfer the coating liquid to the material to be coated.
The chamber is provided with a supply port for supplying the coating liquid.
A coating method for coating the material to be coated by using a coating device having a groove on the outer peripheral surface in which the transfer roll is inclined with respect to the rotation direction.
In the lateral direction of the chamber, the amount of the coating liquid supplied from the supply port is increased on one end side than on the other end side.
The coating method, wherein the one end is the end on the side to which the groove faces when the groove is viewed from the bottom to the top along the rotation direction of the transfer roll.
[11] The supply port has a main supply port and an auxiliary supply port.
The coating method according to the above [10], wherein the auxiliary supply port is arranged so as to be displaced from the central portion to the one end side in the lateral direction of the chamber.
[12] A chamber in which the coating liquid is filled, and
A transfer roll that is arranged so as to come into contact with the coating liquid filled in the chamber, adheres the coating liquid to the outer peripheral surface, and is rotated to transfer the coating liquid to the material to be coated.
The chamber is provided with a supply port for supplying the coating liquid.
The transfer roll has a groove on the outer peripheral surface that is inclined with respect to the rotation direction.
In the lateral direction of the chamber, the amount of the coating liquid supplied from the supply port is larger on one end side than on the other end side.
The one end portion is an end portion on the side to which the groove faces when the groove is viewed from the bottom to the top along the rotation direction of the transfer roll.
[13] A coating method for coating the material to be coated by using the coating apparatus according to any one of the above [1] to [9] and the above [12].

INDUSTRIAL APPLICABILITY The present invention can provide a coating apparatus and a coating method having good coating performance even when the viscosity of the coating liquid is relatively high.

It is a side view which shows the coating apparatus which concerns on 1st Embodiment of this invention. It is a schematic perspective view which looked at the coating apparatus which concerns on 1st Embodiment of this invention from the rear. It is a schematic perspective view which looked at the coating apparatus which concerns on 2nd Embodiment of this invention from the rear. It is a side view which shows the coating apparatus which concerns on 3rd Embodiment of this invention. It is a schematic diagram which shows the modification of the arrangement position of a main supply port.

(First Embodiment)
Hereinafter, the coating apparatus and coating method of the present invention will be described with reference to the drawings. FIG. 1 is a side view showing a coating device 10 according to the first embodiment of the present invention.
As shown in FIG. 1, the coating device 10 includes a chamber 11, a transfer roll 12, a supply port 13, a blade 14, and the like. The chamber 11 is a container in which the coating liquid A is filled, and is sometimes called a liquid receiving pan or the like. The transfer roll 12 is located above the chamber 11. At least a part of the transfer roll 12 is arranged inside the chamber 11 so as to come into contact with the coating liquid A filled inside the chamber 11. The transfer roll 12 attaches the coating liquid A to the outer peripheral surface 12A and rotates it to transfer the coating liquid A to the material to be coated B.

The supply port 13 supplies the coating liquid A to the inside of the chamber 11. The supply port 13 includes a main supply port 31 and an auxiliary supply port 32, as will be described later. The coating liquid A may be supplied to the main supply port 31 and the auxiliary supply port 32 from, for example, a storage tank (not shown).

In the present specification, the direction along the axis of the transfer roll 12, that is, the direction perpendicular to the paper surface of FIG. 1 is the lateral direction of the chamber 11, and both ends of the chamber 11 in the lateral direction are the end portions 11A and 11B, respectively. (See Fig. 2). Further, the side of the chamber 11 where the supply port 13 is provided is the front side of the chamber 11 (that is, the back side of FIG. 2), and the side opposite to the side where the supply port 13 is provided is the rear side of the chamber 11 (that is, the front side of FIG. 2). Side). As shown in FIG. 1, the transfer roll 12 rotates from the front to the rear of the chamber 11 on the lower side thereof, and from the rear to the front on the upper side.
Further, in the present specification, unless otherwise specified, the terms "left" and "right" for convenience mean "left" and "right" when viewed from the rear side of the chamber 11, respectively.

The blade 14 is generally called a doctor blade, and the blade plate 15 is held so as to be sandwiched by the holder 16. At the position P1, the tip of the blade 14 comes into contact with the transfer roller 12 and scrapes off the coating liquid adhering to the transfer roller 12. The position P1 is a position downstream of the position in contact with the coating liquid A inside the chamber 11 in the rotation direction and a position upstream of the position P2 at which the coating liquid A is transferred to the material B to be coated. .. The base end of the blade 14 is fixed to the blade base 18. The blade 14 is brought into contact with the transfer roll 12 from the rear side of the chamber 11. Further, the position P2 is generally arranged on the upper side of the transfer roll 12.

The material B to be coated is supplied so as to come into contact with the outer peripheral surface of the transfer roll 12 at the position P2, and the coating liquid A adhering to the outer peripheral surface 12A of the transfer roll 12 is transferred to the material B to be coated. As a result, the coating liquid A is applied to the material B to be coated. At position P2, the rotation direction of the transfer roll 12 is opposite to the traveling direction of the material B to be coated.

The coating device 10 is provided with a backup roll 20. The backup roll 20 is arranged so as to sandwich the material B to be coated with the transfer roll 12 at the position P2, and pressurizes the material B to be coated. By being pressurized by the backup roll 20, the coating liquid A is easily transferred to the material B to be coated. The outer peripheral surface of the backup roll 20 is formed of rubber, for example. The backup roll 20 may be omitted.

Further, the coating device 10 is provided with a discharge pan 21 adjacent to the chamber 11. The discharge pan 21 receives the coating liquid A overflowing from the chamber 11 and discharges it from the discharge port 22. The coating liquid A discharged from the discharge port 22 may be returned to the storage tank or the like described above through the circulation line.
The discharge pan 21 may be provided on the rear side of the chamber 11. The coating liquid A inside the chamber 11 may overflow due to the rotation of the transfer roll 12, but since the lower side of the transfer roll 12 is rotated from the front to the rear, the coating liquid A is the chamber 11 of the chamber 11. It often overflows from the rear side. Therefore, by arranging the discharge pan 21 on the rear side, the coating liquid A overflowing from the chamber 11 can be efficiently received.

FIG. 2 is a schematic perspective view showing the arrangement positions of the transfer roll 12 and the supply port 13 in the first embodiment. In FIG. 2, the transfer roll 12 is arranged outside the chamber 11 for the sake of explanation, but in reality, as shown in FIG. 1, the transfer roll 12 comes into contact with the coating liquid inside the chamber 13. Arranged to do. The same applies to FIG. 3 described later.

As shown in FIG. 2, the transfer roll 12 has a groove 25 on its outer peripheral surface 12A. The groove 25 is an inclined groove provided so as to be inclined with respect to the rotation direction of the roll 12. The groove 25 is provided, for example, in a spiral shape. The transfer roll 12 is suitably used for so-called "solid coating" in which the coating liquid A is uniformly applied to the material B to be coated by providing the inclined groove. The outer peripheral surface 12A of the transfer roll 12 may be formed of metal, ceramic, or the like, and the groove 25 may be formed, for example, by carving on the outer peripheral surface 12A.
The groove 25 is not particularly limited, but may be, for example, a width of 300 to 1000 μm, a depth of 10 to 1000 μm, and a groove pitch of 50 to 400 pieces / inch along the axial direction. The outer diameter of the transfer roll 12 may be, for example, 3 to 10 cm, and the length in the axial direction may be 30 to 200 cm.

As described above, the chamber 11 is provided with a supply port including a main supply port 31 and an auxiliary supply port 32. The total supply amount of the coating liquid from the main supply port 31 is larger than the supply amount from the auxiliary supply port 32. That is, the coating liquid A is mainly supplied to the chamber 11 from the main supply port 31 and is supplementarily supplied from the auxiliary supply port 32. In the present specification, the supply amount means the volume of the coating liquid supplied per unit time unless otherwise specified.

In the present embodiment, the main supply port 31 has a central supply port 31A arranged in the central portion 11C in the lateral direction of the chamber 11 and a first end portion arranged on the end portion 11A side (left side) of the central portion 11C. It is composed of a side supply port 31B and a second end side supply port 31C arranged on the end 11B side (right side) of the central portion 11C. The first and second end side supply ports 31B and 31C are both arranged between the central portion 11C and the end portions 11A and 11B, respectively. These three supply ports 31A, 31B, and 31C are usually evenly arranged along the lateral direction of the chamber 11.

The auxiliary supply port 32 is arranged so as to be offset from the central portion 11C toward one end portion 11A in the lateral direction of the chamber 11. Here, the arrangement position of the auxiliary supply port 32 is determined according to the direction in which the groove 25 of the transfer roll 12 is inclined. Specifically, the end portion 11A on the side where the auxiliary supply port 32 is provided is the end portion on the side to which the groove 25 faces when the groove 25 is viewed from the bottom to the top along the rotation direction of the transfer roll 12. .. That is, as shown in FIG. 2, the groove 25 of the transfer roll 12 is inclined toward the left when viewed from the bottom to the top from the rear of the chamber 11, and the auxiliary supply port is corresponding to the groove 25. 32 is arranged on the left side of the central portion 11C (that is, on the end portion 11A side).

In the present embodiment, the auxiliary supply port 32 may be arranged in the lateral direction of the chamber 11 so as to be offset from the central portion 11C toward the end portion 11A, and may be arranged at the end portion 11A, as shown in FIG. It is preferable that it is arranged at a position between the central portion 11C and the end portion 11A. By arranging it at a position between the central portion 11C and the end portion 11A, it is possible to prevent the coating liquid supplied from the supply port 13 from being biased toward the end portion 11B, and the liquid level of the coating liquid A in the chamber 11 is prevented. Tends to have a uniform height.

Further, the position of the auxiliary supply port 32 may be arranged so as not to overlap with the supply ports 31A to 31C constituting the main supply port 31 in the lateral direction of the chamber 11. In the present embodiment, for example, it may be arranged between the central supply port 31A and the first end side supply port 32B, but of course, it may be arranged at another position.
As described above, the position that does not overlap with the main supply port 31 is a position where the liquid level of the coating liquid A tends to be low, and by arranging the auxiliary supply port 32 at such a position, the coating inside the chamber 11 is performed. It makes it difficult for the liquid A to be unevenly distributed. Further, the position between the central supply port 31A and the first end side supply port 32B is a position where the liquid level in the chamber 11 tends to be the lowest, and by arranging the auxiliary supply port 32 at that position, the auxiliary supply port 32 can be arranged. It makes it more difficult for the coating liquid A to be unevenly distributed inside the chamber 11.

In the present embodiment, the amount of supply from the main supply port 31 differs between the left side (end 11A side) and the right side (end 11B side). Specifically, the supply amount of the coating liquid from the first end side supply port 31B is larger than the supply amount of the coating liquid from the second end side supply port 31C. As a result, when the groove 25 is viewed from the bottom to the top along the rotation direction of the transfer roll 12, the supply amount from the main supply port 31 on the end side (that is, the left side of the central portion 11C) to which the groove 25 faces is increased. , The amount of the coating liquid supplied from the main supply port 31 on the opposite side (that is, on the right side of the central portion 11C).
The amount of supply from the end-side main supply port (that is, the first end-side supply port 31B) to which the groove 25 faces is the opposite end-side main supply port (that is, the second end). The amount supplied from the side supply port 31C) is not particularly limited, but is preferably 1.5 to 5 times, preferably 2 to 4 times.

Further, the supply amount of the coating liquid from the central supply port 31A is preferably larger than the supply amount of the coating liquid from each of the first and second end side supply ports 31B and 31C. Further, it is more preferable that the supply amount of the coating liquid from the central supply port 31A is larger than the total supply amount of the coating liquids of the first and second end side supply ports 31B and 31C. By increasing the supply amount in the central portion 11C, it is possible to prevent the coating liquid A from being unevenly distributed on the end portions 11A and 11C.

The supply ports 31A to 31C constituting the main supply port 31 are provided on the front side surface 11D of the chamber 11, and are usually arranged below the liquid level of the coating liquid A. Therefore, the coating liquid from the main supply port 31 is supplied into the liquid of the coating liquid A inside the chamber 11. The auxiliary supply port 32 is provided above the side surface 11D. Therefore, the coating liquid from the auxiliary supply port 32 is injected from above the liquid level inside the chamber 11.

The coating device 10 is provided with a groove 25 that is inclined in the transfer roll 12, so that the coating liquid A in the chamber 11 is constant along the direction in which the groove 25 extends as the transfer roll 12 rotates. The coating liquid A inside the chamber 11 tends to be unevenly distributed on the right side (the other end 11B side) of the central portion 11C. Such uneven distribution of the coating liquid A is likely to occur particularly when the coating liquid A has a high viscosity.

In the present embodiment, as described above, the supply amount from the main supply port 31 on the left side is larger than the supply amount from the main supply port 31 on the right side, so that the supply amount of the coating liquid from the supply port 13 is , One end 11A side is larger than the other end 11B side, and uneven distribution of the coating liquid A is prevented by a certain amount. However, when the coating liquid is supplied only from the main supply port 31, the uneven distribution may not be sufficiently eliminated, and a portion where the liquid level height is locally lowered may occur, especially when the viscosity is high. Therefore, in the present embodiment, the liquid level of the coating liquid A inside the chamber 11 is supplied by supplying the coating liquid from the auxiliary supply port 32, which has a small supply amount, to the portion where the liquid level is locally lowered. The height is uniform.
When the liquid level in the chamber 11 becomes a uniform height, it is possible to prevent the coating film formed on the material B to be coated from having streaks or uneven coating. Further, in order to prevent uneven distribution of the coating liquid A, it is not necessary to increase the rotation speed of the transfer roll 12, and it is also possible to prevent a large amount of the coating liquid A from overflowing from the chamber 11 as the rotation speed increases. However, the coating performance will be excellent.

The coating liquid may be continuously supplied from the main supply port 31 and the auxiliary supply port 32 while the transfer roll is rotating. The ratio of the supply amount of the coating liquid from the auxiliary supply port 32 to the supply amount of the coating liquid from the main supply port 31 (that is, the total supply amount of the supply ports 31A to 31C) is 0.02 to 0.2. Is preferable, 0.025 to 0.15 is more preferable, and 0.035 to 0.10. Is even more preferable. When the supply amount ratio is set to these lower limit values or more, for example, even if the viscosity of the coating liquid A is high as shown in the range described later, the coating liquid supplied from the auxiliary supply port 32 causes the coating liquid in the chamber 11 to have a high viscosity. It effectively prevents uneven distribution of the coating liquid A and enables high-speed coating with an appropriate coating amount. Further, by setting the value to the upper limit or less, it is possible to prevent the coating liquid A from being unevenly distributed in the chamber 11 and overflowing due to the coating liquid supplied from the auxiliary supply port 32.

Further, the supply amount of the coating liquid from the auxiliary supply port 32 may be smaller than the supply amount of any of the supply ports 31A to 31C constituting the main supply port 31. Specifically, the supply amount of the coating liquid from the auxiliary supply port 32 is preferably 0.75 or less, more preferably 0.6 or less, with respect to the supply amount of the coating liquid of each of the supply ports 31A to 31C. It is preferably 0.01 or more, more preferably 0.02 or more.

The specific amount of the coating liquid supplied from the main supply port 31 and the auxiliary supply port 32 may be appropriately adjusted according to the size of the transfer roll 12, the coating speed, and the like, and is not particularly limited. The supply amount from the supply port 31 is 5 to 20 L / min. The supply amount from the auxiliary supply port 32 is, for example, 0.1 to 10 L / min. By setting these lower limits or more, the amount of paint supplied is appropriate and high-speed coating is possible. Further, by setting these upper limit values or more, the overflow of the paint from the chamber is suppressed and the coatability is improved.

The coating speed in the coating apparatus 10 is, for example, 5 m / min or more, but from the viewpoint of productivity, a faster coating speed is preferable, preferably 15 m / min or more, more preferably 20 m / min or more, and further preferably 25 m / min or more. It is min or more. The upper limit of the coating speed is not particularly limited, but is set to, for example, 50 m / min or less in order to prevent the coating liquid A from overflowing from the chamber 11 due to the rotation speed of the transfer roll being too high. do it. The coating speed means the length at which the coating liquid A is applied to the material B to be coated in one minute, and is the same as the supply speed of the material B to be coated. Further, the rotation speed of the transfer roll is preferably operated at a speed ratio of 80 to 160% with respect to the coating speed.
Further, the coating amount to be coated material B of the coating liquid A is, for example, at 0.1 mg / cm ² or more, preferably 0.15 mg / cm ² or more, more preferably 0.2 mg / cm ² Above, more preferably 0.3 mg / cm ² or more. The coating amount is, for example, 0.6 mg / cm ² or less. With such a coating amount, it is possible to form an electrode active material layer, an insulating layer, etc. having an appropriate thickness.

In the present embodiment, the material to be coated B is preferably in the form of a sheet or a film. Specifically, it is not particularly limited as long as it can be a material to be coated in gravure coating, such as a metal sheet such as a metal foil, a resin film, a paper base material, a cloth material, and a combination of two or more selected from these. .. Among these, the material B to be coated is preferably a metal sheet such as a metal foil. Examples of the metal constituting the metal sheet include copper, aluminum, titanium, nickel, stainless steel and the like. When the material B to be coated is a metal sheet, the metal sheet may be appropriately surface-treated, or another layer may be laminated on the surface of the metal sheet. Further, the material B to be coated may be a laminated body in which a metal sheet or the like is held by a support such as a resin film or a release sheet.
The thickness of the material B to be coated is not particularly limited, but is, for example, about 1 to 5000 μm, preferably about 10 to 200 μm.

The material B to be coated is preferably an electrode material for various batteries, and is preferably an electrode material for a lithium ion secondary battery. When the material to be coated is an electrode material for a lithium ion secondary battery, it is more preferable that the electrode material constitutes an electrode current collector. When the material to be coated B is an electrode material, the material to be coated is preferably the above-mentioned metal sheet.

The coating liquid A is not limited as long as it can be used as a coating liquid in gravure coating, but various resins, resin compositions obtained by adding various additives to resins, resins or resin compositions are prepared with an organic solvent or water. Examples thereof include a resin coating solution dissolved or dispersed in a resin coating solution, and a slurry solution in which particles and a resin binder are dispersed in an organic solvent or water.
The coating liquid A is preferably a coating liquid for an electrode, particularly an electrode material forming a part of an electrode for a lithium ion secondary battery. For example, a coating liquid for forming an electrode active material layer and a coating for forming an insulating layer. A liquid or the like is preferable. The coating liquid for forming the electrode active material layer is a coating liquid for forming the electrode active material layer on the electrode material, and contains an electrode active material and a resin binder for binding the electrode active material. Further, components other than these, such as a conductive additive, may be optionally contained. The electrode active material may be either a negative electrode active material or a positive electrode active material.
Further, the coating liquid for forming an insulating layer is a coating liquid for forming an insulating layer on an electrode material, and further includes insulating particles and a resin binder for binding the insulating particles, and is further arbitrary. In, components other than these may be contained. The insulating layer is a layer provided on the electrode material in order to ensure the insulating property between the electrode and the separator.
The coating liquid for forming the electrode active material layer and the coating liquid for forming the insulating layer are generally slurry liquids.

In the present embodiment, the viscosity of the coating liquid A is preferably 1700 mPa · s or more. In the coating apparatus 10, as described above, uneven distribution of the coating liquid A tends to occur when the viscosity is high. Therefore, when the viscosity is set to 1700 mPa · s or more, the effect of the present invention due to the provision of the auxiliary supply port 32 can be easily obtained. Further, when the viscosity is set to 1700 mPa · s or more, the adhesion between the material to be coated and the coating film becomes high, and it becomes easy to form a coating film having high peel strength. Further, the amount of coating is increased, and it is possible to make the thickness of the electrode material layer such as the electrode active material layer and the insulating layer formed on the surface of the material B to be coated appropriate. From these viewpoints, the viscosity of the coating liquid A is more preferably 1800 mPa · s or more.

The viscosity of the coating liquid A is preferably 2300 mPa · s or less. When the viscosity is 2300 mPa · s or less, the leveling property of the coating liquid A in the chamber 11 is improved, and high-speed coating can be performed. The viscosity of the coating liquid A is more preferably 2200 mPa · s or less. The viscosity of the coating liquid A is a viscosity measured under the same temperature condition as the liquid temperature of the coating liquid A inside the chamber and at 60 rpm with a B-type viscometer.

As described above, in the present embodiment, the amount of the coating liquid supplied from the supply port 13 is such that one end 11A side (left side) is the other end 11B side according to the direction in which the groove 25 is inclined. (Right side) More. Further, since the coating liquid is also supplied from the auxiliary supply port 32, uneven distribution of the coating liquid A is effectively prevented, the liquid level in the chamber 11 becomes uniform, and the coating performance is excellent. Become.

In this embodiment, whether or not to supply the coating liquid from the auxiliary supply port 32 may be determined according to the properties of the coating liquid A in the chamber 11.
For example, in the coating apparatus 10, the uneven distribution state of the coating liquid A inside the chamber 11 differs depending on the viscosity of the coating liquid A, and when the viscosity is low, the uneven distribution of the coating liquid A is small and the viscosity is high. At this time, the uneven distribution of the coating liquid A becomes large, and the above-mentioned locally lowered liquid level tends to occur.
Therefore, for example, when the coating liquid A has a viscosity less than a predetermined viscosity (for example, 1700 mPa · s), the supply from the auxiliary supply port 32 is stopped and the coating liquid A is supplied only from the main supply port 31. On the other hand, when the coating liquid A has a predetermined viscosity (for example, 1700 mPa · s) or more, the coating liquid A is supplied from the auxiliary supply port 32 in addition to the main supply port 31.
With such a configuration, when the viscosity is high, the uneven distribution of the coating liquid A can be more effectively prevented by supplying the coating liquid from the auxiliary supply port 32. On the other hand, by not supplying the coating liquid from the auxiliary supply port 32 when the coating liquid has a low viscosity, the uneven distribution of the coating liquid A inside the chamber 11 is effective in accordance with the small uneven distribution that occurs when the viscosity is low. Can be prevented. That is, in the present embodiment, for example, by providing the auxiliary supply port 32 having a smaller supply amount than the supply ports 31A to 31C constituting the main supply port 31, and changing the presence or absence of supply to the auxiliary supply port 32, for example. Since the supply of the coating liquid A to the chamber 11 can be finely adjusted according to the properties of the coating liquid, the coating performance can be improved by simple control.

In the above description, an example in which the supply amount of the first end side supply port 31B is larger than the supply amount of the second end side supply port 31C has been described, but the first and second end side supply ports have been described. The supply amounts of the coating liquids 31B and 31C may be the same as each other. Even if they are the same as each other, the uneven distribution of the coating liquid can be prevented by supplying the coating liquid from the auxiliary supply port 32. Such a configuration is effective when the lateral length of the chamber 11 is sufficiently longer than that of the transfer roll, or when the coating liquid has a low viscosity, and the uneven distribution of the coating liquid is relatively small. ..

Further, in the above, the mode in which the supply amount of the central supply port 31A is made larger than the total supply amount of the end side supply ports 31B and 31C and the supply amount of the respective supply ports 31B and 31C is shown. The supply amount of 31A can be set as appropriate. For example, the supply amount of the central supply port 31A may be the same as or less than the total supply amount of the end side supply ports 31B and 31C. Further, the supply amount of the central supply port 31A may be the same as the supply amount of one of the end side supply ports 31B and 31C, or may be the same as the supply amount of both the supply ports 31B and 31C.

(Second embodiment)
FIG. 3 shows a coating device 40 according to a second embodiment of the present invention. In the following description, members having a configuration different from that of the first embodiment are designated by different reference numerals. Further, the members having the same structure are designated by the same reference numerals, and the description thereof will be omitted for the members having the same structure as that of the first embodiment.

In the coating apparatus 10 according to the first embodiment, as shown in FIG. 2, the groove 25 of the transfer roll 12 is inclined toward the left when viewed from the bottom to the top along the rotation direction. The groove 45 of the transfer roll 42 of the present embodiment is formed so as to go to the right when viewed from the bottom to the top along the rotation direction of the transfer roll 42. Here, the arrangement position of the auxiliary supply port of the present invention is determined according to the direction in which the groove of the transfer roll is inclined, as described above. Therefore, in the present embodiment, as shown in FIG. 3, the groove 45 of the transfer roll 42 is inclined toward the right when viewed from the bottom to the top along the rotation direction. The auxiliary supply port 52 is arranged on the right side of the central portion 11C (that is, on the end portion 11B side).

Further, also in the present embodiment, the supply amount of the coating liquid from the main supply port 31 is adjusted to the direction in which the groove 45 is directed, and the supply amount on the end 11B side (right side) is supplied on the end 11A side (left side). It should be more than the amount. That is, the supply amount of the second end side supply port 31C may be larger than the supply amount of the coating liquid of the first end side supply port 31B. However, as for the supply amount of the coating liquid from the main supply port 31, the supply amount on the end portion 11B side may be the same as the supply amount on the end portion 11A side. Further, it is preferable that the supply amount of the central supply port 31A is set in the same manner as in the first embodiment.
Also in the present embodiment, by setting the supply amount from the supply port according to the direction in which the groove 45 is inclined, uneven distribution of the coating liquid A in the chamber 11 is prevented, and the liquid level height in the chamber 11 is prevented. The coating performance becomes uniform and the coating performance is excellent.

(Third Embodiment)
Next, a third embodiment of the present invention will be described. FIG. 4 shows a coating device 60 according to a third embodiment of the present invention. In the coating apparatus 10 of the first embodiment, the coating liquid discharged from the discharge port 22 was returned to the storage tank, but in the present embodiment, it was not returned to the storage tank, as shown in FIG. It is returned to the chamber 11 again from the supply port 13, specifically, the auxiliary supply port 32, through the circulation line 61. That is, the auxiliary supply port 32 may supply the coating liquid circulated by the circulation line 61 to the inside of the chamber 11 instead of supplying a fixed amount of the coating liquid A delivered from the storage tank.
According to such a configuration, the amount of the coating liquid A supplied from the auxiliary supply port 32 corresponds to the amount overflowing from the chamber 11, so that the coating liquid A inside the chamber 11 is actually unevenly distributed. Therefore, the coating liquid A is supplied from the auxiliary supply port 32, and the coating property tends to be good.

The circulation line 61 is provided with a suction / discharge device such as a pump (not shown), and the coating liquid discharged from the discharge port 22 is sucked and discharged by the suction / discharge device and sent to the auxiliary supply port 32. It is good. By providing the suction / discharge device in this way, the coating liquid overflowing from the chamber 11 can be returned to the chamber 11 at high speed.

Also in this embodiment, as shown in each of the above embodiments, the arrangement position of the auxiliary supply port may be determined according to the direction in which the groove of the transfer roll is inclined. Therefore, as shown in FIG. 2, when the groove 25 of the transfer roll 12 is tilted toward the left when the rotation direction is viewed from the bottom to the top from the back surface side of the chamber 11, the groove 25 is tilted from the central portion 11C accordingly. It is preferable that the auxiliary supply port 32 arranged on the left side (that is, the end portion 11A side) is provided. Further, as shown in FIG. 3, when the groove 45 of the transfer roll 12 is tilted toward the right when the rotation direction is viewed from the bottom to the top from the back surface side of the chamber 11, the groove 45 of the transfer roll 12 is tilted from the central portion 11C accordingly. It is preferable that the auxiliary supply port 52 arranged on the right side (that is, the end portion 11B side) is provided.
Further, the amount of the coating liquid supplied from the main supply port 31 may be appropriately set as described in the first embodiment.

Further, in each of the above embodiments, the coating device is provided with the discharge pan 21, but the discharge pan 21 may be omitted. If the discharge pan 21 is omitted, the coating liquid overflowing from the coating apparatus is not returned to the storage tank and is not returned to the inside of the chamber 11 through the circulation line 61.
In each of the above embodiments, the auxiliary supply port is provided, and the amount of supply from the main supply port is appropriately adjusted to prevent uneven distribution of the coating liquid A inside the chamber 11 as described above. Therefore, even if the height of the side surface of the chamber is not so high, the coating liquid A is less likely to overflow from the chamber 11 due to the rotation of the transfer roll 12. Therefore, even if the discharge pan 21 is omitted, problems such as a large amount of the coating liquid A leaking to the outside are less likely to occur.

In each of the above embodiments, the number of main supply ports is three, but the number of main supply ports may be any number as long as it is one or more.
Specifically, when there is one main supply port, as shown in FIG. 5A, the supply port may be arranged in the central portion 11C as the central supply port 36A. When there are two main supply ports, as shown in FIG. 5B, the first and second central supply ports 37A and 37B may be provided so as to sandwich the central portion 11C. The first and second central supply ports 37A and 37B may have the same supply amount, or as shown in the first embodiment, the supply amount is adjusted according to the direction of the groove of the transfer roll. May be done. In the present specification, when the central portion 11C does not have a supply port constituting the main supply port, the central portion 11C is the most located on the end 11A side from the central portion 11C and the end 11B side is located on the central portion 11C. The supply ports located close to each other are defined as the central supply port, and the supply ports 37A and 37B shown in FIG. 5B are the central supply ports.

When there are four main supply ports, as shown in FIG. 5C, first and second central supply ports 38A and 38B are provided so as to sandwich the central portion 10C, and the supply ports are provided. The first and second end-side supply ports 38C and 38D may be provided at positions closer to the ends 11A and 11B than 38A and 38B, respectively.
In this case, for example, the supply amount is appropriately set so that the total supply amount of the first and second central supply ports 38A and 38B is the same as the central supply port 31A of each of the above embodiments. Just do it. Further, the supply amounts of the first and second end side supply ports 38C and 38D are appropriately set so as to be the same supply amounts as the first and second end side supply ports 31B and 31C, respectively. Just do it. The supply ports 38A to 38D are usually arranged at equal intervals in the lateral direction.

Further, for example, when there are five main supply ports, as shown in FIG. 5 (D), the central supply port 39A is provided in the central portion 10C, and the first and second end side supplies are provided. It is preferable that the ports 39B and 39C are arranged between the central portion 11C and the end portion 11A, and the third and fourth end side supply ports 39D and 39E are arranged between the central portion 11C and the end portion 11B. The supply ports 39A to 39E are usually arranged at equal intervals in the lateral direction.
In this case, for example, the supply amount may be appropriately set so that the supply amount of the central supply port 39A is the same as that of the central supply port 31A of each of the above embodiments. Further, the total supply amount of the first and second end side supply ports 39B and 39C is the same as the supply amount of the first end side supply port 31B, and the third and fourth ends. The supply amount may be appropriately set so that the total supply amount of the unit side supply ports 39D and 39E is the same as the supply amount of the second end side supply port 31C.

Further, for example, when there are six or more main supply ports, one or two central supply ports are provided in the central portion 10C, and between the central portion 11C and the end portions 11A, and in the center, as described above. The same number of end-side supply ports may be provided between the portion 11C and the end portion 11B, respectively. Further, six or more main supply ports may also be provided at equal intervals in the lateral direction.
In this case as well, for example, the supply amount may be appropriately set so that the supply amount of the central supply port is the same as that of the central supply port 31A of each of the above embodiments. Further, the total supply amount of the end side supply port between the central portion 11C and the end portion 11A is the same as that of the first end side supply port 31B, and the central portion 11C and the end portion are provided. The supply amount may be appropriately set so that the total supply amount of the end side supply ports between 11B is the same as the supply amount of the second end side supply port 31C.
In each of the configurations of FIGS. 5A to 5D, or in a configuration of 6 or more main supply ports, the auxiliary supply ports may be arranged in the same manner as in each of the above embodiments, for example, in the lateral direction. It is preferable that they are arranged at positions that do not overlap with each supply port that constitutes the main supply port.

In each of the above embodiments, only one auxiliary supply port is shown, but there may be two or more auxiliary supply ports. In this case, the two or more auxiliary supply ports, like the auxiliary supply ports 32 and 52, are the ends on the side where the groove faces when the groove is viewed from the bottom to the top along the rotation direction of the transfer roll. It should be placed on the side. In this case, the total supply amount of the auxiliary supply port may be set in the same manner as the supply amount of the auxiliary supply port 32 (or the auxiliary supply port 52) alone described above. Then, the supply amount of each of the two or more auxiliary supply ports may be smaller than the supply amount of any of the main supply ports. Further, the total supply amount of the auxiliary supply port should be smaller than the total supply amount of the main supply port.

In each of the above embodiments, both the main supply port and the auxiliary supply port are provided as the supply port, but even if only the main supply port is provided, the supply amount of the coating liquid from the supply port is , The auxiliary supply port may be omitted as long as one end side is larger than the other end side. The one end side is the end on the side where the groove faces when the groove is viewed from the bottom to the top along the rotation direction of the transfer roll. For example, in the first embodiment shown in FIG. 2, the center. It is on the left side of the central portion 11C, and on the right side of the central portion 11C in the second embodiment shown in FIG.

Further, in each of the above embodiments, the main supply port is provided on the front side surface 11D of the chamber 11, and the auxiliary supply port is arranged above the side surface 11D. Is not limited to these. For example, the auxiliary supply port may be provided on the side surface 11D, or the main supply port 31 may be provided above the side surface 11D.

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited to these Examples.

[Example 1]
Using the coating apparatus shown in FIGS. 1 and 2, a coating test of the coating liquid A on the material B to be coated was carried out. As the coating liquid A, a slurry liquid (coating liquid for forming an insulating layer) having a concentration of 19% by mass, which contained alumina and a resin binder and was diluted with N-methyl-2-pyrrolidone as a solvent, was prepared. The viscosity of the coating liquid A at 25 ° C. was 2000 mPa · s. As the material B to be coated, a material in which a positive electrode active material layer was coated by 50 μm on an aluminum foil having a thickness of 15 μm was prepared. In the coating device 10, the outer diameter of the transfer roll was 60 mm, the length in the axial direction was 70 cm, the depth of the groove 25 was 150 μm, the groove pitch was 80 pieces / inch, and the capacity of the chamber 11 was 5 L.
In the coating device 10, the supply ports 31B, 31A, and 31C constituting the main supply port 31 are arranged at equal intervals in the lateral direction, and the auxiliary supply port 32 is the first end side supply port 31B and the central supply port. It was placed between 31A.

The temperature of the coating liquid A inside the chamber 11 is adjusted to 25 ° C., and the coating liquid is supplied from the supply ports 31A to 31C and the auxiliary supply port 32 in the supply amounts as shown in Table 1, and the transfer roll 12 The backup roll 20 was rotated to perform coating, and the coating performance was evaluated by the following evaluation method.

[Evaluation methods]
The coating device of this example was evaluated according to the following evaluation criteria.
<High-speed coatability>
The coating liquid A was applied onto the positive electrode active material layer (material to be coated B) under the chamber, transfer roll (gravure roll), liquid supply condition, and the following coating conditions described in each example.
(Coating conditions)
Coating speed: Optional Gravure roll rotation speed: 140%
Width of material B to be coated: 500 mm
By the time the coating is started and the material B to be coated is coated 1000 m, the portion where the coating liquid A is not applied appears on the material B to be coated by 50 mm or more in the width direction. Increase the coating speed. It was evaluated according to the following evaluation criteria.
(Evaluation criteria)
A: 25 m / min or more B: 20 m / min or more and less than 25 m / min C: 15 m / min or more and less than 20 m / min D: less than 15 m / min

<Evaluation of coating amount>
The coating liquid A was applied onto the positive electrode active material layer (material to be coated B) under the chamber, transfer roll (gravure roll), liquid supply condition, and the following coating conditions described in each example.
(Coating conditions)
Coating speed: 20m / min
Gravure roll rotation speed: 140%
Width of material B to be coated: 500 mm
When the coating was started and the material B to be coated was coated for 30 to 100 m, the coating weight of the coating liquid A on the material B to be coated was measured and evaluated according to the following evaluation criteria. The calculation method is shown below.
(Coating weight) = {(Weight after coating)-(Weight before coating)} ÷ (Area)
If the weight of the same part cannot be measured, the uncoated part is formed near the coated part by forming a part where the gravure roll is not intentionally brought into contact with the material B to be coated, and the uncoated part is cut off after coating. The coating weight is calculated by measuring and comparing.
(Evaluation criteria)
A: 0.3 mg / cm ² or more B: 0.2 mg / cm ² or more and less than 0.3 mg / cm ² C: 0.15 mg / cm ² or more and less than 0.2 mg / cm ² D: 0.15 mg / cm less than ²

[Examples 2 and 3]
Examples 2 and 3 were carried out in the same manner as in Example 1 except that the concentrations of the slurry liquid were set to 17% by mass and 16% by mass, respectively, and the viscosity of the coating liquid A was changed as shown in Table 1. ..

[Examples 4 and 5]
The same procedure as in Example 1 was carried out except that the amount of the coating liquid supplied from the auxiliary supply port 32 was designed to be as shown in Table 1.

[Example 6]
The same procedure as in Example 1 was carried out except that the coating liquid was not supplied from the auxiliary supply port 32.

[Example 7]
The same procedure as in Example 6 was carried out except that the supply amounts of the first end side supply port 31B and the central supply port 31A constituting the main supply port 31 were designed to be as shown in Table 1.

In each of the above examples, when the material to be coated was coated with a coating liquid having a relatively high viscosity, the grooves were seen from the bottom to the top along the rotation direction of the transfer roll. Occasionally, the amount of coating liquid supplied on the end side (left side) to which the groove faces is made larger than the amount of coating liquid supplied on the other end side (right side) so that the coating film does not overflow from the chamber. The coating could be done without streaks or uneven coating.
Further, as shown in each embodiment, the coating liquid is supplied from the auxiliary supply port, and the ratio of the supply amount from the auxiliary supply port to the supply amount from the main supply port and the viscosity of the coating liquid are predetermined. By adjusting to the range, the coating amount and high-speed coating property became excellent.

A brief description of the sign

10 Coating equipment 11 Chamber 11A, 11B End 11C Central part 12, 42 Transfer roll 13 Supply port 14 Blade 20 Backup roll 21 Discharge pan 22 Discharge port 25, 45 Groove 31 Main supply port 32, 52 Auxiliary supply port 31A, 36A, 37A, 37B, 38A, 38B, 39A Central supply port 31B, 38C, 39B First end side supply port 31C, 38D, 39C Second end side supply port 39D Third end side supply port 39E Fourth end side supply port 61 Circulation line A Coating liquid B Coating material

Claims (12)

A chamber filled with coating liquid and
A transfer roll that is arranged so as to come into contact with the coating liquid filled in the chamber, adheres the coating liquid to the outer peripheral surface, and is rotated to transfer the coating liquid to the material to be coated.
The chamber is provided with a supply port for supplying the coating liquid.
The supply port has a main supply port and an auxiliary supply port.
The transfer roll has a groove on the outer peripheral surface that is inclined with respect to the rotation direction.
The auxiliary supply port is arranged so as to be offset from the central portion to one end side in the lateral direction of the chamber, and the one end portion extends the groove from below along the rotation direction of the transfer roll. when viewed above, Ri ends der on the side where the groove is directed,
The lateral direction of the chamber is the direction along the axis of the transfer roll.
The main supply port is composed of one or more supply ports, and the supply amount from the auxiliary supply port is smaller than the supply amount of any of the supply ports constituting the main supply port.
A coating device in which the auxiliary supply port is arranged so as not to overlap each supply port constituting the main supply port in the lateral direction of the chamber . The coating device according to claim 1, wherein in the lateral direction of the chamber, the amount of the coating liquid supplied from the supply port is larger on one end side than on the other end side. The coating device according to claim 1 or 2, wherein the auxiliary supply port is arranged between the central portion and the one end portion. The transfer roller is placed on the transfer roller on the downstream side in the rotational direction from the position where the coating liquid is filled in the chamber in contact with the coating liquid and on the upstream side in the rotational direction from the position where the coating liquid is transferred to the material to be coated. The coating apparatus according to any one of claims 1 to 3, further comprising a blade for scraping the adhered coating liquid. The coating apparatus according to any one of claims 1 to 4, wherein the viscosity of the coating liquid is 1700 to 2300 mPa · s. The amount of the coating liquid supplied from the auxiliary supply port is 0.02 to 0.2 of the amount of the coating liquid supplied from the main supply port, according to any one of claims 1 to 5. Coating equipment. The coating device according to any one of claims 1 to 6 , wherein the material to be coated is an electrode material for a lithium ion secondary battery. The coating apparatus according to any one of claims 1 to 7 , further comprising a circulation line for circulating the coating liquid overflowing from the chamber and supplying the coating liquid from the auxiliary supply port. A chamber filled with coating liquid and
A transfer roll that is arranged so as to come into contact with the coating liquid filled in the chamber, adheres the coating liquid to the outer peripheral surface, and is rotated to transfer the coating liquid to the material to be coated.
The chamber is provided with a supply port for supplying the coating liquid.
A coating method for coating the material to be coated by using a coating device having a groove on the outer peripheral surface in which the transfer roll is inclined with respect to the rotation direction.
In the lateral direction of the chamber, the amount of the coating liquid supplied from the supply port is increased on one end side than on the other end side.
It said one end, when viewed on the groove along the rotational direction of the transfer roll from below, Ri ends der on the side where the groove is directed,
The supply port has a main supply port and an auxiliary supply port.
The auxiliary supply port is arranged so as to be offset from the central portion to the one end side in the lateral direction of the chamber .
The lateral direction of the chamber is the direction along the axis of the transfer roll.
The main supply port is composed of one or more supply ports, and the supply amount from the auxiliary supply port is smaller than the supply amount of any of the supply ports constituting the main supply port.
A coating method in which the auxiliary supply port is arranged so as not to overlap each supply port constituting the main supply port in the lateral direction of the chamber . A coating method for coating the material to be coated using the coating apparatus according to any one of claims 1 to 8. The first aspect of any one of claims 1 to 8 , wherein the main supply port is provided on the front side surface of the chamber, and the transfer roll rotates from the front to the rear of the chamber on the lower side thereof. Coating equipment. One of claims 1 to 8 and 11 , wherein the auxiliary supply port is provided above the front side surface of the chamber, and the transfer roll rotates below the front side surface of the chamber from the front to the rear of the chamber. The coating device described in the section.

Images