CN112118915A

CN112118915A - Coating device and coating method

Info

Publication number: CN112118915A
Application number: CN201980032979.1A
Authority: CN
Inventors: 寺西利绘; 岩田瞬
Original assignee: Sekisui Chemical Co Ltd
Current assignee: Sekisui Chemical Co Ltd
Priority date: 2018-03-20
Filing date: 2019-03-08
Publication date: 2020-12-22
Also published as: JP6846569B2; JPWO2019181581A1; WO2019181581A1

Abstract

The coating device (10) is provided with: a chamber (11) filled with a coating liquid (A); a transfer roller (12) which is disposed so as to be in contact with the coating liquid (A) filled in the chamber (11), and which transfers the coating liquid (A) to the material to be coated by rotating the coating liquid (A) while adhering the coating liquid (A) to the outer circumferential surface (12A); and a supply port for supplying the coating liquid to the chamber (11). The supply port has a main supply port (31) and an auxiliary supply port (32), the transfer roller (12) has a groove (25) inclined with respect to the rotation direction on the outer circumferential surface 12A, the auxiliary supply port (32) is disposed in the lateral direction of the chamber (11) so as to be offset toward any one end portion (11A) side with respect to the central portion (11C), and the one end portion (11A) is the end portion toward which the groove (25) faces when the groove (25) is viewed from below in the rotation direction of the transfer roller (12).

Description

Coating device and coating method

Technical Field

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

Background

Conventionally, there are known: the gravure coating device is configured to adhere a coating liquid to an outer circumferential surface of a transfer roller by bringing the transfer roller into contact with the coating liquid filled in the chamber and rotating, and to transfer the adhered coating liquid to a material to be coated. The transfer roller used in the gravure coating device is formed with: grooves for holding the coating liquid on the roller surface. Gravure coating apparatuses have been conventionally used in various fields, for example, for coating metal foils with electrode materials and the like (see, for example, patent document 1).

Documents of the prior art

Patent document

Patent document 1, Japanese patent laid-open publication No. 2011-

Disclosure of Invention

Technical problem to be solved by the invention

When the electrode material is applied, the electrode material is generally a slurry, and the viscosity of the slurry may be high. However, when a coating liquid having a high viscosity is applied to a material to be coated, streaks or coating unevenness may occur in the coating film depending on the groove shape of the transfer roller. Streaks and coating unevenness are eliminated by, for example, increasing the rotational speed of the transfer roller, but as the rotational speed and the rotation of the roller are increased, the amount of the coating liquid overflowing out of the chamber increases. As a result, the amount of the coating liquid adhering to the transfer roller is reduced, and there is a risk of occurrence of coating omission or the like.

The present invention has been made in view of the above problems, and it is an object of the present invention to provide: provided are a coating device and a coating method, which can prevent the occurrence of streaks, uneven coating, or coating omission in a coating film even when the viscosity of a coating liquid is high, and which have good coating performance.

Means for solving the problems

As a result of intensive studies, the present inventors have found that: the above problems can be solved by supplying the coating liquid to the arrangement position of the supply port of the chamber or setting the supply amount of the supply port according to the shape of the groove formed on the outer circumferential surface of the transfer roller, and the following invention has been completed. The gist of the present invention is: the following [1] to [13 ].

[1] A coating device is provided with:

a chamber filled with a coating liquid;

a transfer roller which is disposed so as to be in contact with the coating liquid filled in the chamber, and which transfers the coating liquid to a material to be coated by attaching the coating liquid to an outer circumferential surface and rotating the coating liquid; and

a supply port that supplies the coating liquid to the chamber, wherein,

the supply port has a main supply port and an auxiliary supply port,

the transfer roller has a groove inclined with respect to a rotational direction on an outer circumferential surface,

the auxiliary supply port is disposed in a lateral direction of the chamber so as to be offset to any one end portion side of a central portion, the one end portion being an end portion on a side of the groove when the groove is viewed from below in a rotational direction of the transfer roller.

[2] The coating apparatus according to [1], wherein a supply amount of the coating liquid from the supply port is larger on the one end side than on the other end side in a lateral direction of the chamber.

[3] The coating apparatus according to [1] or [2], wherein the auxiliary supply port is disposed between the central portion and the one end portion.

[4] The coating apparatus according to any one of [1] to [3], further comprising, on a downstream side in a rotational direction of a position where the coating liquid filled in the chamber comes into contact with the coating liquid and on an upstream side in the rotational direction of a position where the coating liquid is transferred to the material to be coated: and a blade which scrapes off the coating liquid adhering to the transfer roller.

[5] The coating apparatus according to any one of [1] to [4], wherein the viscosity of the coating liquid is 1700 to 2300 mPas.

[6] The coating apparatus according to any one of [1] to [5], wherein a supply amount of the coating liquid from the auxiliary supply port is 0.02 to 0.2 of a supply amount of the coating liquid from the main supply port.

[7] The application device according to any one of [1] to [6], wherein the main supply port includes 1 or more supply ports, and a supply amount from the auxiliary supply port is lower than a supply amount of any one of the supply ports constituting the main supply port.

[8] The coating apparatus according to any one of [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 [1] to [8], comprising: a circulation line that circulates the coating liquid overflowing from the chamber and supplies the coating liquid through the auxiliary supply port.

[10] A coating method for coating a material to be coated with a coating apparatus,

the coating device is provided with:

a chamber filled with a coating liquid;

a supply port that supplies the coating liquid to the chamber, wherein,

in a lateral direction of the chamber, a supply amount of the coating liquid from the supply port is larger on one end side than on the other end side,

the one end portion is an end portion of the groove facing a side when the groove is viewed from below upward in a rotational direction of the transfer roller.

[11] The coating method according to [10], wherein,

the supply port has a main supply port and an auxiliary supply port,

the auxiliary supply port is disposed in a lateral direction of the chamber so as to be offset toward the one end portion side with respect to a central portion.

[12] A coating device is provided with:

a chamber filled with a coating liquid;

a supply port that supplies the coating liquid to the chamber, wherein,

[13] An application method of applying the material to be applied using the application apparatus according to any one of the above [1] to [9] and [12 ].

ADVANTAGEOUS EFFECTS OF INVENTION

The present invention can provide: an apparatus and a method for coating which have excellent coating performance even when the viscosity of the coating liquid is high.

Drawings

Fig. 1 is a side view of a coating apparatus according to embodiment 1 of the present invention.

Fig. 2 is a schematic perspective view of the coating apparatus according to embodiment 1 of the present invention viewed from the rear.

Fig. 3 is a schematic perspective view of a coating apparatus according to embodiment 2 of the present invention viewed from the rear.

Fig. 4 is a side view of a coating apparatus according to embodiment 3 of the present invention.

FIG. 5 is a schematic view showing a modification of the arrangement position of the main supply port.

(embodiment 1)

Hereinafter, a coating apparatus and a coating method according to the present invention will be described with reference to the drawings. Fig. 1 is a side view showing a coating apparatus 10 according to embodiment 1 of the present invention.

As shown in fig. 1, the coating apparatus 10 includes: chamber 11, transfer roller 12, supply port 13, blade 14, and the like. The chamber 11 is a container filled with the coating liquid a therein, and is sometimes referred to as a liquid receiving pan or the like. The transfer roller 12 is disposed above the chamber 11. At least a part of the transfer roller 12 is disposed inside the chamber 11 so as to be in contact with the coating liquid a filled inside the chamber 11. The transfer roller 12 is configured to rotate while attaching the coating liquid a to the outer circumferential surface 12A, thereby transferring the coating liquid a to the material B to be coated.

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 described below. For example, the coating liquid a is preferably supplied from a reservoir tank, not shown, to the main supply port 31 and the auxiliary supply port 32.

In the present specification, the direction along the axis of the transfer roller 12, i.e., the direction perpendicular to the paper surface of fig. 1, is defined as the lateral direction of the chamber 11, and the

ends

11A and 11B are defined as the ends of the chamber 11 in the lateral direction, respectively (see fig. 2). The side of the chamber 11 where the supply port 13 is provided is referred to as the front side of the chamber 11 (i.e., the inner side in fig. 2), and the side opposite to the side where the supply port 13 is provided is referred to as the rear side of the chamber 11 (i.e., the front side in fig. 2). As shown in fig. 1, the transfer roller 12 rotates backward from the front of the chamber 11 at the lower side and forward from the rear at the upper side.

In the present specification, if not otherwise specified, for convenience, the terms "left" and "right" refer to "left" and "right" respectively when viewed from the rear side of the chamber 11.

The blade 14 is generally called a doctor blade, and the blade plate 15 is sandwiched and held by a holder 16. The blade 14 contacts the transfer roller 12 at a position P1 at the tip end portion, and scrapes off the coating liquid adhering to the transfer roller 12. Position P1 is: at the downstream side in the rotational direction of the position in contact with the coating liquid a inside the chamber 11 and at the position on the upstream side in the rotational direction of the position P2 where the coating liquid a is transferred to the material B to be coated. The base end of the blade 14 is fixed to a blade table 18. The blade 14 is in contact with the transfer roller 12 from the rear side of the chamber 11. The position P2 is normally disposed above the transfer roller 12.

The coating material B is supplied so as to contact the outer circumferential surface of the transfer roller 12 at a position P2, and the coating liquid a adhering to the outer circumferential surface 12A of the transfer roller 12 is transferred to the coating material B, whereby the coating liquid a is applied to the coating material B. At the position P2, the rotation direction of the transfer roller 12 is opposite to the proceeding direction of the material B to be coated.

The coating apparatus 10 is provided with a backup roller 20. The backup roller 20 is disposed so as to sandwich the material B to be coated between the backup roller and the transfer roller 12 at a position P2, and pressurizes the material B to be coated. The coating liquid a is easily transferred to the material B by pressurization with the backup roller 20. As the backup roller 20, for example, the outer circumferential surface thereof is formed of rubber. The backup roller 20 may be omitted.

In the coating apparatus 10, a discharge tray 21 is provided adjacent to the chamber 11. The discharge tray 21 receives the coating liquid a overflowing from the chamber 11 and discharges it from the discharge port 22. It is preferable that coating liquid A discharged from discharge port 22 is returned to the storage tank or the like through a circulation line.

The discharge tray 21 is preferably provided on the rear side of the chamber 11. Although the coating liquid a in the chamber 11 sometimes overflows due to the rotation of the transfer roller 12, the coating liquid a often overflows from the rear side of the chamber 11 because it rotates from the front to the rear on the lower side of the transfer roller 12. Therefore, by disposing the discharge pan 21 on the rear side, the coating liquid a overflowing from the chamber 11 can be received efficiently.

Fig. 2 is a schematic perspective view showing the arrangement positions of the transfer roller 12 and the supply port 13 in embodiment 1. Although the transfer roller 12 is disposed outside the chamber 11 for convenience of explanation in fig. 2, the transfer roller 12 is actually disposed inside the chamber 13 so as to be in contact with the coating liquid as shown in fig. 1. The same applies to fig. 3 described later.

As shown in fig. 2, the transfer roller 12 has a groove 25 in its outer circumferential surface 12A. The groove 25 is an inclined groove provided to be inclined with respect to the rotation direction of the roller 12. The groove 25 is, for example, provided in a spiral shape. The transfer roller 12 is preferably used for so-called "solid coating" in which the coating liquid a is uniformly applied to the material B by providing the inclined grooves. The outer circumferential surface 12A of the transfer roller 12 may be formed of metal, ceramic, or the like, and the groove 25 is preferably engraved on the outer circumferential surface 12A.

The grooves 25 are not particularly limited, but may have a width of 300 to 1000 μm, a depth of 10 to 1000 μm, and an axial groove pitch of 50 to 400 pieces/inch. The transfer roller 12 may have an outer diameter of, for example, 3 to 10c m and an axial length of 30 to 200 cm.

The chamber 11, as described above, 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 supplied mainly from the main supply port 31 to the chamber 11 and supplementarily from the auxiliary supply port 32. In the present specification, the supply amount refers to the volume of the coating liquid supplied per unit time unless otherwise specified.

In the present embodiment, the main supply port 31 includes: the center supply port 31A of the center portion 11C disposed in the lateral direction of the chamber 11, the 1 st end portion side supply port 31B disposed closer to the end portion 11A side (left side) than the center portion 11C, and the 2 nd end portion side supply port 31C disposed closer to the end portion 11B side (right side) than the center portion 11C. The 1 st and 2 nd end portion

side supply ports

31B, 31C are disposed between the central portion 11C and the

end portions

11A, 11B, respectively. These 3

supply ports

31A, 31B, and 31C are generally arranged uniformly in the lateral direction of the chamber 11.

The auxiliary supply port 32 is disposed offset from the center portion 11C toward the one end portion 11A in the lateral direction of the chamber 11. Here, the position of the auxiliary supply port 32 is determined according to the direction of inclination of the groove 25 of the transfer roller 12. Specifically, the end 11A on the side where the auxiliary supply port 32 is provided is an end on the side toward which the groove 25 faces when the groove 25 is viewed from below in the rotational direction of the transfer roller 12. That is, as shown in fig. 2, since the groove 25 of the transfer roller 12 is inclined to the left when viewed from the rear of the chamber 11 from below, the auxiliary supply port 32 is disposed to be shifted to the left (i.e., the end 11A side) from the center portion 11C.

In the present embodiment, the auxiliary supply port 32 may be disposed in the lateral direction of the chamber 11 so as to be shifted from the center portion 11C toward the end portion 11A, or may be disposed in the end portion 11A, but is preferably disposed at a position between the center portion 11C and the end portion 11A as shown in fig. 2. The coating liquid supplied from the supply port 13 is prevented from being biased toward the end portion 11B by being disposed at a position between the central portion 11C and the end portion 11A, and the liquid level of the coating liquid a in the chamber 11 is made to have a uniform height.

It is preferable that the auxiliary supply port 32 is disposed so as not to overlap 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 is preferable to dispose between the center supply port 31A and the 1 st end side supply port 32B, but it is needless to say that they may be disposed at other positions.

Thus, the position not overlapping the main supply port 31 is a position where the liquid level of the coating liquid a is likely to become low, and by disposing the auxiliary supply port 32 at such a position, the coating liquid a inside the chamber 11 is less likely to be unevenly distributed. Further, the position between the center supply port 31A and the 1 st end side supply port 32B is a position where the liquid level in the chamber 11 is most likely to become low, and by disposing the auxiliary supply port 32 at this position, the coating liquid a in the chamber 11 is less likely to be unevenly distributed.

In the present embodiment, the amount of supply from the main supply port 31 is different between the left side (end 11A side) and the right side (end 11B side). Specifically, the supply amount of the coating liquid from the 1 st end portion side supply port 31B is larger than the supply amount of the coating liquid from the 2 nd end portion side supply port 31C. Thus, when the groove 25 is viewed from below upward in the rotational direction of the transfer roller 12, the amount of supply of the coating liquid from the main supply port 31 on the end side of the groove 25 (i.e., on the left side from the central portion 11C) is larger than the amount of supply of the coating liquid from the main supply port 31 on the opposite side (i.e., on the right side from the central portion 11C).

The amount of supply from the main supply port toward the end portion side (i.e., the 1 st end portion side supply port 31B) of the trench 25 is not particularly limited, but is preferably 1.5 to 5 times, and more preferably 2 to 4 times, the amount of supply from the main supply port toward the end portion side opposite to the main supply port (i.e., the 2 nd end portion side supply port 31C).

Further, the supply amount of the coating liquid from the central supply port 31A is preferably larger than the supply amounts of the coating liquids from the 1 st and 2 nd end

side supply ports

31B and 31C, respectively. The amount of the coating liquid supplied from the central supply port 31A is more preferably larger than the total amount of the coating liquid supplied from the 1 st and 2 nd end

side supply ports

31B and 31C. By increasing the supply amount in the central portion 11C, the coating liquid a at the

end portions

11A, 11C is prevented from being unevenly distributed.

The supply ports 31A to 31C constituting the main supply port 31 are provided on the side surface 11D on the front side of the chamber 11, and are usually disposed below the liquid surface 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 surface in the chamber 11.

In the coating apparatus 10, the inclined grooves 25 are provided in the transfer roller 12, and the coating liquid a in the chamber 11 is caused to flow in a constant direction in which the grooves 25 extend as the transfer roller 12 rotates, whereby the coating liquid a in the chamber 11 is likely to be unevenly distributed from the central portion 11C to the right (the other end portion 11B side). In particular, when the coating liquid a has a high viscosity, such unevenness in the distribution of the coating liquid a is likely to occur.

In the present embodiment, as described above, since the supply amount from the left main supply port 31 is larger than the supply amount from the right main supply port 31, the supply amount of the coating liquid from the supply port 13 is larger on the one end portion 11A side than on the other end portion 11B side, and the distribution of the coating liquid a is prevented from being uneven to some extent. However, in the case of supplying the coating liquid only from the main supply port 31, particularly when the viscosity is high, the uneven distribution may not be sufficiently eliminated, and a portion where the liquid level is locally lowered may be generated. Therefore, in the present embodiment, the coating liquid is supplied from the auxiliary supply port 32 having a small supply amount to the portion where the local liquid level height is low, so that the liquid level height of the coating liquid a in the chamber 11 is uniform.

When the liquid level in the chamber 11 has a uniform height, the coating film formed on the material B to be coated is prevented from being streaked or from being unevenly coated. Further, in order to prevent the distribution of coating liquid a from being uneven, it is not necessary to increase the rotation speed of transfer roller 12, and coating liquid a is prevented from overflowing from chamber 11 in a large amount as the rotation speed increases, resulting in excellent coating performance.

The supply of the coating liquid from the main supply port 31 and the auxiliary supply port 32 is preferably performed continuously during the rotation of the transfer roller. 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 (i.e., the total supply amount of the supply ports 31A to 31C) is preferably 0.02 to 0.2, more preferably 0.025 to 0.15, and still more preferably 0.035 to 0.10. When the supply amount ratio is set to be equal to or higher than these lower limit values, even when the viscosity of the coating liquid a is high as shown in a range described later, for example, the coating liquid a supplied from the auxiliary supply port 32 can effectively prevent the distribution of the coating liquid a in the chamber 11 from being uneven, and can be applied at a high speed with an appropriate application amount. When the upper limit value is less than or equal to the upper limit value, the coating liquid a is supplied from the auxiliary supply port 32, thereby preventing the coating liquid a from being unevenly distributed in the chamber 11 and overflowing.

The supply amount of the coating liquid from the auxiliary supply port 32 is preferably 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, preferably 0.01 or more, and more preferably 0.02 or more, with respect to the supply amount of the coating liquid from each of the supply ports 31A to 31C.

Specifically, the supply amount of the coating liquid from the main supply port 31 and the auxiliary supply port 32 may be appropriately adjusted according to the size, coating speed, and the like of the transfer roller 12, and is not particularly limited, and the supply amount from the main supply port 31 is, for example, 5 to 20L/min. The amount of the liquid supplied from the auxiliary supply port 32 is, for example, 0.1 to 10L/min. By setting these lower limit values or more, the amount of the paint supplied can be adjusted to be appropriate, and high-speed coating can be performed. By setting these upper limit values or more, the paint is prevented from overflowing from the cavity, and the coating property is improved.

The coating speed in the coating apparatus 10 is, for example, 5m/min or more, but from the viewpoint of productivity, it is preferably high, preferably 15m/min or more, more preferably 20m/min or more, and still more preferably 25m/min or more. The upper limit of the coating speed is not particularly limited, and may be set to, for example, 50m/min or less in order to prevent the coating liquid a from overflowing from the chamber 11 due to an excessively high rotation speed of the transfer roller. The coating speed is a length of coating liquid a coated on the material B per minute, and is the same as the feeding speed of the material B. The rotational speed of the transfer roller is preferably 80 to 160% of the coating speed.

The coating amount of the coating liquid A to the material B to be coated is, for example, 0.1mg/cm²Above, preferably 0.15mg/cm²Above, more preferably 0.2mg/cm²Above, more preferably 0.3mg/cm²The above. Further, the coating amount is, for example, 0.6mg/cm²The following. By setting the amount of application to this value, an electrode active material layer, an insulating layer, and the like having an appropriate thickness can be formed.

In the present embodiment, the material B to be coated is preferably in a sheet or film form. Specifically, there are no particular limitations on the material that can be used as the material to be coated in gravure coating, such as a metal sheet such as a metal foil, a resin film, a paper substrate, a cloth material, and a combination of 2 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 subjected to an appropriate surface treatment, and another layer may be laminated on the surface of the metal sheet. The material B to be coated may be a laminate in which a metal sheet or the like is held on a support such as a resin film or a release sheet.

The thickness of the material B to be coated is not particularly limited, and is, for example, 1 to 5000. mu.m, preferably about 10 to 200. mu.m.

The material B to be coated is preferably an electrode material for various batteries, and is preferably an electrode material for lithium ion secondary batteries. When the material to be coated is an electrode material for a lithium ion secondary battery, the electrode material is more preferably a material constituting an electrode collector. When the material B to be coated is an electrode material, the material to be coated is preferably the metal sheet.

Coating liquid a is not particularly limited as long as it can be used in gravure coating, and examples thereof include: various resins, resin compositions obtained by adding various additives to resins, resin coating liquids obtained by dissolving or dispersing resins or resin compositions in organic solvents or water, slurry liquids obtained by dispersing particles and resin binders in organic solvents or water, and the like.

The coating liquid a may be a coating liquid for an electrode material constituting an electrode, particularly a part of an electrode for a lithium ion secondary battery, and is preferably, for example, a coating liquid for forming an electrode active material layer, a coating liquid for forming an insulating layer, or the like. The coating liquid for forming an electrode active material layer is a coating liquid for forming an electrode active material layer on an electrode material, and contains an electrode active material and a resin binder for binding the electrode active material, and may further optionally contain other components such as a conductive auxiliary agent. The electrode active material may be a negative electrode active material or a positive electrode active material.

The coating liquid for forming an insulating layer is a coating liquid for forming an insulating layer on an electrode material, and contains insulating particles and a resin binder for binding the insulating particles, and may further optionally contain components other than these. The insulating layer is a layer provided on the electrode material in order to ensure insulation between the electrode and the separator.

The electrode active material layer forming coating liquid and the insulating layer forming coating liquid are typically slurry liquids.

In the present embodiment, the viscosity of coating liquid a is preferably 1700mPa · s or more. In the coating apparatus 10, as described above, the distribution unevenness of the coating liquid a is liable to occur at the time of high viscosity. Therefore, the effect of the present invention by providing the auxiliary supply port 32 can be easily obtained by setting the viscosity to 1700mPa · s or more. Further, by setting the viscosity to 1700mPa · s or more, the adhesion between the material to be coated and the coating film can be easily improved, and a coating film having high peel strength can be formed. Further, the coating amount can be increased, and 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 can be adjusted to a suitable value. From these viewpoints, the viscosity of coating liquid a is more preferably 1800mPa · s or more.

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

As described above, in the present embodiment, the supply amount of the coating liquid from the supply port 13 is larger on the one end portion 11A side (left side) than on the other end portion 11B side (right side) in accordance with the inclination direction of the groove 25. Further, since the coating liquid is also supplied from the auxiliary supply port 32, the distribution of the coating liquid a is effectively prevented from being uneven, so that the liquid level in the chamber 11 is uniform, and excellent coating performance is obtained.

In the present embodiment, whether or not to supply the coating liquid from the auxiliary supply port 32 may be determined according to the characteristics of the coating liquid a in the chamber 11.

For example, in the coating apparatus 10, the state of the distribution unevenness of the coating liquid a in the chamber 11 changes depending on the viscosity of the coating liquid a, the distribution unevenness of the coating liquid a becomes small at a low viscosity, and the distribution unevenness of the coating liquid a becomes large at a high viscosity, and the local liquid level height becomes liable to be lowered.

Therefore, for example, when the viscosity of coating liquid a is lower than a predetermined viscosity (for example, 1700mPa · s), the supply from the auxiliary supply port 32 is stopped, and coating liquid a is supplied only from the main supply port 31. On the other hand, when the viscosity of coating liquid a is not less than a predetermined viscosity (e.g., 1700mPa · s), 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 distribution of the coating liquid a can be more effectively prevented from becoming uneven by the supply of the coating liquid from the auxiliary supply port 32. On the other hand, when the viscosity of the coating liquid is low, the coating liquid is not supplied from the auxiliary supply port 32, and the distribution of the coating liquid a in the chamber 11 can be effectively prevented from being uneven by a small distribution unevenness generated at the time of low viscosity. That is, in the present embodiment, by providing the auxiliary supply port 32 having a supply amount lower than that of each of the supply ports 31A to 31C constituting the main supply port 31 and changing the presence or absence of supply of the auxiliary supply port 32, it is possible to finely adjust the supply of the coating liquid a to the chamber 11 in accordance with, for example, the characteristics of the coating liquid, and thus it is possible to obtain good coating performance by simple control.

In the above, the 1 st end side supply port 31B is supplied in a larger amount than the 2 nd end side supply port 31C, but the 1 st and 2 nd end

side supply ports

31B and 31C may be supplied in the same amount as each other. Even in the case of being identical to each other, the distribution of the coating liquid can be prevented to some extent from being uneven by the supply of the coating liquid from the auxiliary supply port 32. Such a configuration is effective in the case where the lateral length of the chamber 11 is sufficiently longer than the transfer roller, and the distribution of the coating liquid is less uneven when the coating liquid has a low viscosity.

In the above, the embodiment in which the supply amount of the center supply port 31A is set to be larger than the total supply amount of the end

side supply ports

31B and 31C and the supply amount of each of the

supply ports

31B and 31C has been described, but the supply amount of the center supply port 31A may be set as appropriate. For example, the supply amount of the center supply port 31A may be the same as or less than the total supply amount of the end

side supply ports

31B, 31C. The supply amount of the center supply port 31A may be the same as that of one of the end

side supply ports

31B and 31C, or may be the same as that of both the

supply ports

31B and 31C.

(embodiment 2)

Fig. 3 shows a coating apparatus 40 according to embodiment 2 of the present invention. In the following description, components having different configurations from those of embodiment 1 are given different reference numerals. Note that the same reference numerals are given to members having the same configuration, and the description of the members having the same configuration as that of embodiment 1 is omitted.

In the coating apparatus 10 according to embodiment 1, the groove 25 of the transfer roller 12 is inclined to the left as viewed from below in the rotational direction as shown in fig. 2, but the groove 45 of the transfer roller 42 according to the present embodiment is formed such that: and faces right when viewed from below upward in the rotational direction of the transfer roller 42. Here, the position of the auxiliary supply port according to the present invention is determined according to the inclination direction of the groove of the transfer roller, as described above. Therefore, in the present embodiment, since the groove 45 of the transfer roller 42 is inclined rightward when viewed from below in the rotational direction as shown in fig. 3, the auxiliary supply port 52 is disposed so as to be shifted rightward (i.e., toward the end portion 11B) from the center portion 11C.

In the present embodiment, it is also preferable that the amount of the coating liquid supplied from the main supply port 31 is larger on the side of the end portion 11B (right side) than on the side of the end portion 11A (left side) depending on the direction in which the groove 45 is directed. That is, the supply amount of the 2 nd end portion side supply port 31C is preferably larger than the supply amount of the coating liquid to the 1 st end portion side supply port 31B. However, the amount of the coating liquid supplied from the main supply port 31 may be the same on the side of the end portion 11B as on the side of the end portion 11A. It is preferable that the central supply port 31A be set to a supply amount in the same manner as in embodiment 1.

In the present embodiment, the amount of supply from the supply port is also set in accordance with the inclination direction of the groove 45, so that the distribution of the coating liquid a in the chamber 11 is prevented from becoming uneven, the liquid level in the chamber 11 is made uniform, and excellent coating performance is obtained.

(embodiment 3)

Next, embodiment 3 of the present invention will be explained. Fig. 4 shows a coating apparatus 60 according to embodiment 3 of the present invention. In the coating apparatus 10 according to embodiment 1, the coating liquid discharged from the discharge port 22 is returned to the reservoir tank, but in the present embodiment, the coating liquid is not returned to the reservoir tank, and is returned again to the chamber 11 from the supply port 13, specifically, from the auxiliary supply port 32, through the circulation line 61, as shown in fig. 4. That is, the auxiliary supply port 32 can supply the coating liquid circulated through the circulation line 61 into the chamber 11 instead of a certain amount of the coating liquid a sent out from the reserve tank.

With such a configuration, since the amount of the coating liquid a supplied from the auxiliary supply port 32 is based on the amount of the coating liquid a overflowing from the chamber 11, the coating liquid a is supplied from the auxiliary supply port 32 in accordance with the actual uneven distribution state of the coating liquid a inside the chamber 11, and good coatability is easily obtained.

The circulation line 61 may be provided with a suction/discharge device such as a pump, not shown, for sucking the coating liquid discharged from the discharge port 22 by the suction/discharge device, discharging the coating liquid, and sending the coating liquid to the auxiliary supply port 32. By providing such a suction/discharge device, the coating liquid overflowing from the chamber 11 can be returned to the chamber 11 at a high speed.

In the present embodiment, as in the above-described embodiments, the position at which the auxiliary supply port is disposed may be determined according to the inclination direction of the groove of the transfer roller. Therefore, as shown in fig. 2, when the groove 25 of the transfer roller 12 is inclined to the left when viewed from the rear side of the chamber 11 in the rotating direction from the bottom to the top, it is preferable to provide an auxiliary supply port 32 disposed to the left (i.e., the end 11A side) from the center portion 11C. As shown in fig. 3, when the groove 45 of the transfer roller 12 is inclined to the right when viewed from the rear side of the chamber 11 in the rotation direction from the bottom to the top, it is preferable to provide an auxiliary supply port 52 disposed to the right (i.e., the end 11B side) from the center portion 11C.

The amount of the coating liquid supplied from the main supply port 31 may be set as appropriate as described in embodiment 1.

In each of the above embodiments, the discharge tray 21 is provided in the coating device, but the discharge tray 21 may be omitted. When the discharge pan 21 is omitted, the coating liquid overflowing from the coating device is not returned to the storage tank and is not returned to the inside of the chamber 11 through the circulation line 61.

In the above embodiments, the auxiliary supply port is provided, and the supply amount from the main supply port is appropriately adjusted, whereby the uneven distribution of the coating liquid a inside the chamber 11 is prevented as described above. Therefore, even in the case where the height of the side surface of the chamber is not so high, coating liquid a is made less likely to overflow from the chamber 11 by the rotation of the transfer roller 12. Therefore, even if the discharge tray 21 is omitted, a problem such as leakage of a large amount of the coating liquid a to the outside is unlikely to occur.

In the above embodiments, the number of main supply ports is 3, but the number of main supply ports may be 1 or more.

Specifically, when the number of main supply ports is 1, as shown in fig. 5(a), the supply ports may be disposed in the center portion 11C as the center supply port 36A. When there are two main supply ports, as shown in fig. 5(B), the 1 st and 2 nd

center supply ports

37A and 37B may be provided so as to sandwich the center portion 11C. The 1 st and 2 nd

center supply ports

37A and 37B may be set to the same supply amount, or the supply amount may be adjusted in accordance with the direction in which the grooves of the transfer roller are oriented as in embodiment 1. In the present specification, in the case where there is no supply port constituting the main supply port in the central portion 11C, the supply ports located at the positions closest to the central portion 11C out of the positions closer to the end portion 11A from the central portion 11C and closer to the end portion 11B from the central portion 11C are defined as the central supply ports, and the

supply ports

37A and 37B shown in fig. 5(B) are defined as the central supply ports.

In the case of 4 main supply ports, as shown in fig. 5(C), the 1 st and 2 nd

center supply ports

38A and 38B may be provided so as to sandwich the center portion 10C, and the 1 st and 2 nd end portion

side supply ports

38C and 38D may be provided at positions closer to the

end portions

11A and 11B than the

supply ports

38A and 38B, respectively.

In this case, for example, the supply amount may be set as appropriate so that the total supply amount of the 1 st and 2 nd

center supply ports

38A and 38B becomes the same supply amount as the center supply port 31A in each of the above embodiments. The supply amounts may be set appropriately so that the 1 st and 2 nd end portion

side supply ports

38C and 38D are the same as the 1 st and 2 nd end portion

side supply ports

31B and 31C, respectively. The supply ports 38A to 38D are usually arranged at equal intervals in the lateral direction.

For example, in the case where the number of main supply ports is 5, as shown in fig. 5(D), the center supply port 39A may be provided in the center portion 10C, the 1 st and 2 nd end portion

side supply ports

39B and 39C may be disposed between the center portion 11C and the end portion 11A, and the 3 rd and 4 th end portion side supply ports 39D and 39E may be disposed between the center 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 set as appropriate so that the supply amount of the center supply port 39A becomes the same supply amount as the center supply port 31A in each of the above embodiments. The supply amount may be set appropriately so that the total supply amount of the 1 st and 2 nd end portion

side supply ports

39B, 39C becomes the same supply amount as the 1 st end portion side supply port 31B, and the total supply amount of the 3 rd and 4 th end portion side supply ports 39D, 39E becomes the same supply amount as the 2 nd end portion side supply port 31C.

For example, when the number of main supply ports is 6 or more, 1 or two center supply ports may be provided in the center portion 10C, and the same number of end portion side supply ports may be provided between the center portion 11C and the end portion 11A and between the center portion 11C and the end portion 11B, respectively, in the same manner as described above. In the case of 6 or more main supply ports, they may be provided at regular intervals in the lateral direction.

In this case, for example, the supply amount may be set as appropriate so that the supply amount from the center supply port is the same as the supply amount from the center supply port 31A in each of the above embodiments. The supply amount may be set as appropriate so that the total supply amount of the end portion side supply ports between the center portion 11C and the end portion 11A becomes the same supply amount as the 1 st end portion side supply port 31B and the total supply amount of the end portion side supply ports between the center portion 11C and the end portion 11B becomes the same supply amount as the 2 nd end portion side supply port 31C.

In the respective configurations of fig. 5(a) to (D) or the configuration in which the number of main supply ports is 6 or more, the auxiliary supply ports may be arranged in the same manner as in the respective embodiments described above, and for example, preferably arranged at positions not overlapping with the respective supply ports constituting the main supply ports in the lateral direction.

In each of the above embodiments, the configuration in which only 1 auxiliary supply port is provided is shown, but two or more auxiliary supply ports may be provided. In this case, it is preferable that the two or more auxiliary supply ports are both disposed on the end portion side of the groove facing the groove when the groove is viewed from below in the rotational direction of the transfer roller, similarly to the

auxiliary supply ports

32 and 52. In this case, the total supply amount of the auxiliary supply ports is preferably set in the same manner as the supply amount of the individual auxiliary supply ports 32 (or the auxiliary supply ports 52) described above. Further, it is preferable that the supply amount of each of the two or more auxiliary supply ports is lower than the supply amount of any one of the main supply ports. Further, the total supply amount of the auxiliary supply port is preferably lower than the total supply amount of the main supply port.

In the above embodiments, both the main supply port and the auxiliary supply port are provided as the supply ports, but even in the case where only the main supply port is provided, the auxiliary supply port may be omitted as long as the supply amount of the coating liquid from the supply port is larger on one end side than on the other end side. The one end portion side means an end portion of the groove facing the side when the groove is viewed from below upward in the rotational direction of the transfer roller, and for example, the one end portion is shifted to the left side from the center portion 11C in embodiment 1 shown in fig. 2, and the one end portion is shifted to the right side from the center portion 11C in embodiment 2 shown in fig. 3.

In the above embodiments, the main supply port is provided on the side surface 11D on the front side of the chamber 11, and the auxiliary supply port is disposed above the side surface 11D. For example, the auxiliary supply port may be provided on the side surface 11D, and the main supply port 31 may be provided above the side surface 11D.

Examples

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]

A coating test of coating liquid a on material to be coated B was performed using the coating apparatus shown in fig. 1 and 2. Coating liquid a contains alumina and a resin binder, and is diluted with N-methyl-2-pyrrolidone as a solvent to prepare a slurry liquid (coating liquid for forming an insulating layer) having a concentration of 19 mass%. Coating liquid A had a viscosity of 2000 mPas at 25 ℃. As the coating material B, a material in which a positive electrode active material layer was coated to a thickness of 50 μm on an aluminum foil having a thickness of 15 μm was prepared. In the coating apparatus 10, the transfer roller had an outer diameter of 60mm, a length in the axial direction of 70cm, a depth of the groove 25 of 150 μm, a groove pitch of 80 pieces/inch, and a capacity of the chamber 11 of 5L.

In the coating apparatus 10, the

supply ports

31B, 31A, 31C constituting the main supply port 31 are arranged at equal intervals in the lateral direction, and the auxiliary supply port 32 is disposed between the 1 st end side supply port 31B and the center supply port 31A.

Coating liquid a in chamber 11 was adjusted to a temperature of 25 ℃, and coating liquid was supplied from supply ports 31A to 31C and auxiliary supply port 32 at supply amounts shown in table 1, and was applied by rotating transfer roller 12 and backup roller 20, and coating performance was evaluated by the following evaluation method.

[ evaluation method ]

The coating apparatus of the present example was evaluated according to the following evaluation criteria.

< high-speed coatability >

Coating liquid a was applied on the positive electrode active material layer (coating material B) by the chamber, transfer roller (gravure roll), liquid feeding condition and the following coating condition described in each example.

(coating conditions)

Coating speed: at will

Rotation speed of gravure roll: 140 percent

Width of material B to be coated: 500mm

Coating was started until 1000m of the material B to be coated was coated, and the coating speed was increased so that a portion of the material B to be coated where 50mm or more of the coating liquid a was not coated appeared in the width direction was evaluated by the following evaluation criteria.

(evaluation criteria)

A: more than 25m/min

B: more than 20m/min and less than 25m/min

C: 15m/min or more and less than 20m/min

D: less than 15m/min

< evaluation of coating amount >

(coating conditions)

Coating speed: 20m/min

Rotation speed of gravure roll: 140 percent

Width of material B to be coated: 500mm

When the coating is started and the material B to be coated is coated for 30 to 100m, the coating weight of the material B to be coated by the coating liquid A is measured, and the coating weight is evaluated according to the following evaluation criteria. The calculation method is shown below.

(coating weight) { (weight after coating) } (weight before coating) } ÷ (area)

When the same weight measurement cannot be performed, a portion where the gravure roll is not brought into contact with the material B to be coated is formed, an uncoated portion is formed in the vicinity of the coated portion, and the uncoated portion is cut out and measured after coating, and the coating weight is obtained by comparison.

(evaluation criteria)

A：0.3mg/cm²The above

B：0.2mg/cm²Above and below 0.3mg/cm²

C：0.15mg/cm²Above and below 0.2mg/cm²

D: less than 0.15mg/cm²

[ 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 liquids were set to 17% by mass and 16% by mass, respectively, and the viscosities of coating liquids a were set to those shown in table 1.

[ examples 4 and 5]

The same procedure as in example 1 was carried out, except that the supply amount of the coating liquid from the auxiliary supply port 32 was set to the amount 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 1 st end portion side supply port 31B and the center supply port 31A constituting the main supply port 31 were set as shown in table 1.

[ Table 1]

In each of the above examples, the material to be coated was coated with the coating liquid having a relatively high viscosity, and when the groove was observed from below in the rotational direction of the transfer roller, the supply amount of the coating liquid toward the end portion side (left side) of the groove was made larger than the supply amount of the coating liquid toward the other end portion side (right side), so that the coating could be performed without overflowing from the chamber, without causing streaks in the coating film, or without causing uneven coating.

Further, as shown in each example, the coating liquid was 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 were adjusted to predetermined ranges, whereby an excellent coating amount and high-speed coatability were obtained.

Description of the symbols

10 coating device

11 chamber

11A, 11B end

11C center part

12. 42 transfer roller

13 supply port

14 doctor blade

20 backup roll

21 discharge tray

22 discharge port

25. 45 ditch

31 main supply port

32. 52 auxiliary supply port

31A, 36A, 37B, 38A, 38B, 39A central supply port

31B, 38C, 39B, 1 st end side supply port

31C, 38D, 39C 2 nd end side supply port

39D 3 rd end side supply port

39E 4 th end side supply port

61 circulation line

Coating solution A

B coating material

Claims

1. A coating device is provided with:

a chamber filled with a coating liquid;

a supply port that supplies the coating liquid to the chamber, wherein,

the supply port has a main supply port and an auxiliary supply port,

2. The coating apparatus according to claim 1,

in a lateral direction of the chamber, a supply amount of the coating liquid from the supply port is larger on the one end side than on the other end side.

3. The coating apparatus according to claim 1 or 2,

the auxiliary supply port is disposed between the center portion and the one end portion.

4. The coating apparatus according to any one of claims 1 to 3, further comprising, in a downstream side in a rotational direction of a position in contact with the coating liquid filled inside the chamber and an upstream side in the rotational direction of a position in which the coating liquid is transferred to the material to be coated:

and a blade which scrapes off the coating liquid adhering to the transfer roller.

5. The coating apparatus according to any one of claims 1 to 4,

the viscosity of the coating liquid is 1700 to 2300 mPas.

6. The coating apparatus according to any one of claims 1 to 5,

the supply amount of the coating liquid from the auxiliary supply port is 0.02 to 0.2 of the supply amount of the coating liquid from the main supply port.

7. The coating apparatus according to any one of claims 1 to 6,

the main supply port includes 1 or more supply ports, and the supply amount from the auxiliary supply port is lower than the supply amount from any one of the supply ports constituting the main supply port.

8. The coating apparatus according to any one of claims 1 to 7,

the material to be coated is an electrode material for a lithium ion secondary battery.

9. The coating apparatus according to any one of claims 1 to 8, comprising:

a circulation line that circulates the coating liquid overflowing from the chamber and supplies the coating liquid through the auxiliary supply port.

10. A coating method for coating a material to be coated with a coating apparatus,

the coating device is provided with:

a chamber filled with a coating liquid;

a supply port which supplies the coating liquid to the chamber, and

11. The coating method according to claim 10,

the supply port has a main supply port and an auxiliary supply port,

12. A coating device is provided with:

a chamber filled with a coating liquid;

a supply port that supplies the coating liquid to the chamber, wherein,

13. A coating method for coating the material to be coated using the coating apparatus as set forth in any one of claims 1 to 9 and claim 12.