JP2017148763A - Coating application device, coating application method, and method for manufacturing laminate film using the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a coating application device that can obtain sufficiently and stably a uniform coating film.SOLUTION: The coating application device includes a slit die. The slit die (10) includes: at least one coating liquid discharging slit (13); an uppermost stream side lip (11); and a lowermost stream side lip (12). The lowermost stream side lip (12) has a tip face (12a) and an outer side face (12b) that define an angle (θ) of less than 90 degrees and the outer side face (12b) is coated with a water-repellent film.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a coating apparatus provided with a slit die, a coating method, and a method for producing a laminated film using the coating device.

  A coating device equipped with a slit die is normally applied to the surface of a substrate by spreading the coating solution supplied from the supply port in the horizontal direction at the manifold and discharging the coating solution extruded from the manifold from the discharge slit. A film is formed. There are lips on both sides of the tip of the discharge slit, and the coating liquid is applied to the base material that is relatively conveyed with a predetermined gap (clearance).

  The coating apparatus provided with the slit die has a problem that the coating property and the coating film uniformity are easily influenced by the stability of the beads (liquid reservoir) formed in the clearance. For example, FIG. 7 is a schematic cross-sectional view of a conventional coating apparatus. As shown in FIG. 7, a part of the bead (40) spreads on the outer surface (12b) of the downstream lip (12). ) May cause coating stripes and coating unevenness.

  In order to suppress the above problem, the coating liquid contact angle on the outer surface of the lip is made larger than the coating liquid contact angle on the tip surface of the lip (Patent Documents 1 and 2), and the water contact angle of the downstream lip tip is upstream It has been proposed to make it larger than the water contact angle of the tip of the side lip (Patent Document 3) and to provide a water-repellent treatment layer on the side surface of the lip (Patent Document 4).

JP-A-8-173878 JP 2004-50025 A JP 2002-248399 A JP 2007-330900 A

  However, the conventional techniques as described above have not yet achieved a uniform coating film sufficiently stably. For example, depending on the type and physical properties (viscosity, surface tension, etc.) of thin film coating, high-speed coating, or coating solution, a uniform coating film may not be obtained stably.

  Accordingly, an object of the present invention is to provide a coating apparatus and a coating method capable of obtaining a uniform coating film sufficiently stably. Moreover, it is providing the manufacturing method of the laminated | multilayer film using the coating device and coating method of this invention.

The above object of the present invention has been achieved by the following invention.
[1] A coating apparatus provided with a slit die, wherein the slit die (10) includes at least one coating liquid discharge slit (13), the most upstream lip (11), and the most downstream lip (12). An angle (θ ₁ ) between the distal end surface (12a) of the most downstream lip (12) and the outer surface (12b) is less than 90 degrees, and the outer surface (12b) is a water repellent film A coating apparatus characterized by being coated.
[2] The coating apparatus according to [1], wherein an outer side surface (11b) of the most upstream lip (11) is covered with a water repellent film.
[3] The coating apparatus according to [1] or [2], wherein the water-repellent film is a carbon film.
[4] The coating apparatus according to [3], wherein the carbon film is a DLC film.
[5] The coating apparatus according to [4], wherein the DLC film is a fluorinated DLC film.
[6] Any one of [1] to [5], wherein an angle (θ ₂ ) formed between the tip surface (11a) and the outer surface (11b) of the most upstream lip (11) is less than 90 degrees. Coating device.
[7] The coating apparatus according to any one of [1] to [6], wherein a distal end surface (11a) of the most upstream lip (11) is covered with a hydrophilic film.
[8] The coating apparatus according to [7], wherein the hydrophilic film is a hydrophilic DLC film.
[9] The coating apparatus according to any one of [1] to [8], further including a decompression unit upstream of the slit die.
[10] A coating method in which an aqueous coating solution is applied to a substrate using the coating apparatus according to any one of [1] to [9].
[11] Using the coating apparatus according to any one of [1] to [9], a coating solution having a viscosity at 23 ° C. of 30 mPa · s or less is applied to a substrate with a wet film thickness of 30 μm or less. Application method.
[12] A method for producing a laminated film, wherein a coating film is obtained by applying a coating solution to a substrate using the coating apparatus according to any one of [1] to [9].
[13] A method for producing a laminated film, wherein the coating method is applied to a substrate using the coating method according to [10] or [11] to obtain a laminated film.

  ADVANTAGE OF THE INVENTION According to this invention, the coating device from which a uniform coating film is obtained sufficiently stably, the coating method, and the manufacturing method of a laminated film using the same can be provided.

FIG. 1 is a cross-sectional view schematically showing the main part of one embodiment of a slit die used in the coating apparatus of the present invention. FIG. 2 is an enlarged cross-sectional view of a portion indicated by A in FIG. FIG. 3 is a cross-sectional view schematically showing a main part of one embodiment of the slit die used in the coating apparatus of the present invention. 4 is an enlarged cross-sectional view of a portion indicated by B in FIG. FIG. 5 is a cross-sectional view schematically showing a main part of an embodiment of a coating apparatus provided with the slit die and the decompression unit of the present invention. FIG. 6 is a cross-sectional view schematically showing the main part of one embodiment of the slit die used in the coating apparatus of the present invention. FIG. 7 is a schematic cross-sectional view of a conventional coating apparatus.

  DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments according to the present invention will be described in detail with reference to the drawings. In addition, this invention is not limited to the following embodiment. Moreover, it can change suitably in the range which does not deviate from the range which has the effect of this invention. In addition, the arrow X shown in FIGS. 1-6 shows the conveyance direction of the base material 30. FIG. In the following description, the upstream side in the substrate conveyance direction (arrow X) may be simply referred to as “upstream side”, and the downstream side in the substrate conveyance direction (arrow X) may be simply referred to as “downstream side”. 1 to 6 schematically show a part of the configuration of the coating apparatus, and do not show actual dimensions.

  FIG. 1 is a schematic cross-sectional view of a main part of one embodiment of a slit die used in the coating apparatus of the present invention, and FIG. 2 is an enlarged cross-sectional view of a portion indicated by A in FIG. The coating apparatus of the present invention includes a slit die 10, and the slit die 10 has at least one coating liquid discharge slit 13, the most upstream lip 11, and the most downstream lip 12. It is preferable that a manifold (not shown) is provided above the coating liquid discharge slit 13, and the coating liquid supplied from the supply port is spread in the lateral direction (application width direction) by the manifold, and the coating liquid discharge slit. To be supplied.

  A slit die 10 according to the present invention has a most upstream lip 11 on the upstream side of the coating liquid discharge slit 13 and a most downstream lip 12 on the downstream side. The coating liquid discharged from the coating liquid discharge slit 13 forms a bead (liquid reservoir) in the gap (clearance) between the most upstream lip 11 and the most downstream lip 12 and the substrate 30. Applied. The clearance dimension H is usually about 20 to 500 μm, but in the case of thin film coating described later, the range of 20 to 200 μm is preferable from the viewpoint of stabilizing the bead, and the range of 30 to 150 μm is more preferable. A range of ˜100 μm is particularly preferred.

  Although FIG. 1 shows an aspect in which only one coating liquid discharge slit is provided, the number of coating liquid discharge slits may be two or more. FIG. 6 shows a configuration of a slit die having two coating liquid discharge slits, which is the same as the configuration of FIG. 1 except that a central lip 14 is provided between the coating liquid discharge slits 13a and 13b. It is.

Features of the slit die according to the present invention, the angle theta ₁ between the front end surface 12a and the outer surface 12b of the lip 12 of the most downstream side is less than 90 degrees, and the outer surface 12b is water-repellent film (not shown) It is in being covered with. When the most downstream lip 12 adopts the above-described configuration, a part of the coating liquid that forms the bead 40 is prevented from spreading (climbing) on the outer surface 12b, and coating stripes and coating unevenness due to this phenomenon are suppressed. Is done. As a result, a uniform coating film can be obtained stably.

The angle θ ₁ formed between the distal end surface 12a and the outer surface 12b of the most downstream lip 12 is further preferably 80 ° or less, more preferably 70 ° or less, from the viewpoint of suppressing wetting and spreading of the outer surface 12b by the coating liquid. preferable. The lower limit angle is preferably 30 degrees or more from the viewpoint of maintaining the strength of the lip.

  In the slit die according to the present invention, the distal end surface 12a of the most downstream lip 12 is preferably not covered with a water repellent film. That is, it is preferable that the front end surface 12a is in the same state as the slit die forming material (for example, stainless steel). In this case, the tip surface 12a is preferably mirror-finished, and the surface roughness of the tip surface 12a is such that the maximum height Ry in accordance with JIS B 0601-1984 is 0.2S (μm) or less. Is preferred.

  Examples of the water-repellent film coated on the outer surface 12b include a carbon film, a nickel plating film, a fluorine resin-containing nickel plating film, a fluorine resin film, a silicone resin film, a polypropylene resin film, and a polyethylene resin film. Among these, a carbon film is preferable because of its high water repellency and excellent wear resistance, durability, adhesion, and the like, and among the carbon films, a DLC (diamond-like carbon) film is preferable.

  The method for coating the water-repellent film is appropriately selected according to the material to be coated, and examples thereof include coating, plating, baking, vapor deposition, sputtering, plasma CVD, and thermal spraying.

  The thickness of the water repellent film is preferably in the range of 0.1 to 20 μm, more preferably in the range of 0.3 to 10 μm, and particularly preferably in the range of 0.5 to 7 μm. If the thickness of the water repellent film is less than 0.1 μm, the water repellent film may not function sufficiently. On the other hand, if the thickness exceeds 20 μm, the water repellent film may be cracked.

  The water repellent film preferably has a water contact angle of 70 degrees or more, more preferably 80 degrees or more, and particularly preferably 90 degrees or more. The upper limit is not particularly limited, but is about 160 degrees.

[DLC film]
A DLC film suitable as a water repellent film will be described in detail.
The DLC film can be formed using a known method. For example, sputtering, DC magnetron sputtering, RF magnetron sputtering, chemical vapor deposition (CVD), plasma CVD, plasma ion implantation, superimposed RF plasma ion implantation, ion plating, arc ion play It can be formed by a coating method, an ion beam deposition method, a laser ablation method, a thermal spraying method, or the like.

Examples of the material for forming the DLC film include gases such as hydrocarbon compounds. Such hydrocarbon compounds include alkanes such as methane (CH ₄ ), ethane (C ₂ H ₆ ), propane (C ₃ H ₈ ), butane (C ₄ H ₁₀ ), cyclopropane (C ₃ H ₆ ), cyclobutane. Cycloalkanes such as (C ₄ H ₈ ), ethylene (C ₂ H ₄ ), alkenes such as propene (C ₃ H ₆ ), butene (C ₄ H ₈ ), alkynes such as acetylene (C ₂ H ₂ ), benzene And aromatic hydrocarbons such as (C ₆ H ₆ ) and toluene (C ₇ H ₈ ). The water contact angle of the DLC film formed of the above material is 70 degrees or more.

  Further, in order to further improve the water repellency of the DLC film, fluorine, aluminum or silicon can be contained in the DLC film. For example, it can be carried out by adding a gas containing fluorine, aluminum, or silicon such as fluorinated hydrocarbon, alkoxide, or silane to the source gas.

  The water repellent film according to the present invention preferably has a high water repellency. From this viewpoint, a fluorinated DLC film is preferable. Such a fluorinated DLC film can be formed by using a fluorinated hydrocarbon compound as a raw material.

Examples of such fluorinated hydrocarbon compounds include fluorinated alkanes, fluorinated cycloalkanes, fluorinated alkenes, fluorinated cycloalkenes, and fluorinated aromatic compounds. Specifically, 4 fluorinated carbon (CF ₄ ), 6 fluorinated 2 carbon (C ₂ F ₆ ), 8 fluorinated 4 carbon (C ₄ F ₈ H ₂ ), fluorinated benzene (monofluorobenzene (C ₆₎ FH ₅ ), difluorobenzene (C ₆ F ₂ H ₄ ), trifluorobenzene (C ₆ F ₃ H ₃ ), tetrafluorobenzene (C ₆ F ₄ H ₂ ), pentafluorobenzene (C ₆ F ₅ H), Hexafluorobenzene (C ₆ F ₆ ), bis (trifluoromethyl) benzene ((CF ₃ ) ₂ C ₆ H ₄ )) and the like.

  The water contact angle of the fluorinated DLC film is 80 degrees or more, and can be 90 degrees or more by adjusting (increasing) the fluorine content.

[Slit die]
Hereinafter, the preferable aspect of the slit die concerning this invention is demonstrated.

  In the slit die according to the present invention, the outer surface 11b of the lip 11 located on the most upstream side is preferably covered with a water repellent film (not shown). This further stabilizes the bead 40 and suppresses the occurrence of coating stripes and coating unevenness. In particular, stabilization of the bead 40 at the start of application (when discharging an excessive amount of application liquid) is achieved.

  The water-repellent film coated on the outer side surface 11b is the same as the water-repellent film coated on the outermost surface 12b of the most downstream lip described above. That is, the water repellent film coated on the outer surface 11b is preferably a carbon film, more preferably a DLC film, and particularly preferably a fluorinated DLC film. The thickness of the water repellent film is preferably in the range of 0.1 to 20 μm, more preferably in the range of 0.3 to 10 μm, and particularly preferably in the range of 0.5 to 7 μm. The water contact angle of the water repellent film is preferably 70 degrees or more, more preferably 80 degrees or more, and particularly preferably 90 degrees or more. The upper water contact angle is not particularly limited, but is about 160 degrees.

  The slit die according to the present invention preferably further has the configuration shown in FIG. 4 is an enlarged cross-sectional view of a portion indicated by B in FIG.

In other words, it is preferable the angle theta ₂ between the distal end surface 11a and the outer surface 11b of the most upstream side of the lip 11 is less than 90 degrees. As a result, spreading of the outer surface 11b by the coating liquid is suppressed, and the bead 40 is stabilized. Further, the angle θ ₂ is preferably 80 degrees or less, and more preferably 70 degrees or less. The lower limit angle is preferably 30 degrees or more from the viewpoint of maintaining the strength of the lip 11.

  In the embodiment of FIG. 3, the outer surface 11b is more preferably covered with a water repellent film (not shown) as described above.

In the slit die according to the present invention, it is preferable that the front end surface 11a of the most upstream lip 11 is covered with a hydrophilic film (not shown). The hydrophilic film preferably has a water contact angle of 60 degrees or less, more preferably 50 degrees or less, and particularly preferably 40 degrees or less. The lower water contact angle is not particularly limited, but is about 10 degrees.
The bead 40 is further stabilized by covering the distal end surface 11a of the most upstream lip 11 with a hydrophilic film.

  The thickness of the hydrophilic film is preferably in the range of 0.1 to 20 μm, more preferably in the range of 0.3 to 10 μm, and particularly preferably in the range of 0.5 to 7 μm.

For example, a hydrophilic DLC film is preferably exemplified as the hydrophilic film. Such a hydrophilic DLC film can be formed by adding oxygen or nitrogen to the DLC film. For example, a hydrocarbon-based gas (similar to the above-described hydrocarbon compound for forming the DLC film) is supplied into the vacuum chamber by plasma CVD or the like, and O ₂ is supplied to react these gases. However, it can be formed by depositing.

The water contact angle of the hydrophilic DLC film can be adjusted to 60 degrees or less, further 50 degrees or less, or further 40 degrees or less, for example, by adjusting (increasing) the supply amount of O ₂ .

  The coating apparatus according to the present invention preferably has a decompression unit on the upstream side of the slit die. FIG. 5 is a schematic cross-sectional view of a coating apparatus including a slit die and a decompression unit. A decompression unit 20 is provided on the upstream side of the slit die 10.

  The decompression unit 20 includes a decompression chamber 21, decompression means (vacuum pump) (not shown), and an air discharge pipe. When the decompression chamber 21 is decompressed, the upstream side of the bead 40 is decompressed and the bead 40 is stabilized.

  In order to stabilize the bead 40, the upstream meniscus 40a of the bead 40 is preferably pinned in the region of the distal end surface 11a of the most upstream lip 11, and is particularly preferably pinned in the vicinity of the distal end portion 11c. The upstream meniscus 40a of the bead 40 can be pinned to the above-described position (in the region of the distal end surface 11a) by controlling the decompression condition of the decompression unit 20.

  Further, since the distal end surface 11a of the most upstream lip 11 is covered with a hydrophilic film, the upstream meniscus 40a of the bead 40 can be stably pinned to the above position (in the region of the distal end surface 11a). .

  Further, since the outer surface 11b of the most upstream lip 11 is covered with a water-repellent film, the upstream meniscus 40a of the bead 40 can be stably pinned to the above position (in the region of the tip surface 11a). .

Furthermore, by the angle theta ₂ between the distal end surface 11a and the outer surface 11b on the most upstream side lip 11 is less than 90 degrees, the upstream meniscus 40a of the bead 40 the position (the area of the distal end surface 11a) Pinning can be performed stably.

  Stable pinning of the meniscus 40a on the upstream side of the bead 40 to the above position (in the region of the front end surface 11a) means that the bead 40 does not retreat downstream, and the outer side surface 12b of the most upstream lip 12 This contributes to the suppression of wetting and spreading of the coating liquid onto the surface.

That is, the characteristic configuration of the coating apparatus of the present invention, i.e., the angle theta ₁ between the front end surface 12a and the outer surface 12b of the lip 12 of the most downstream side is less than 90 degrees, and the outer surface 12b is water repellent By combining the structure (i) covered with the film and at least one of the following structures (ii) to (v), the wetting spread of the coating liquid on the outer surface 12b of the most upstream lip 12 is further achieved. Can be suppressed.

<Configuration (ii)>
A configuration in which the outer surface 11b of the most upstream lip 11 is covered with a water repellent film.

<Configuration (iii)>
Configuration angle theta ₂ between the distal end surface 11a and the outer surface 11b on the most upstream side lip 11 is less than 90 degrees.

<Configuration (iv)>
A configuration in which the tip surface 11a of the most upstream lip 11 is covered with a hydrophilic film.

<Configuration (v)>
A configuration having a decompression unit upstream of the slit die.

[Measurement of water contact angle of water-repellent film and hydrophilic film]
The water contact angle of the water repellent film and the hydrophilic film can be measured by the following method.

<Production of test piece>
A test piece is prepared by coating a surface of a stainless steel plate (HPM38; surface finish 0.4S) with a thickness of 3 mm with a water repellent film or a hydrophilic film with a thickness of 3 μm.

<Measurement of water contact angle>
Measure water contact angle of water repellent film or hydrophilic film formed on test piece using automatic contact angle meter (DM-500) manufactured by Kyowa Interface Science Co., Ltd. and analysis software FAMAS (version 3.34) To do.
Pure water is used for the measurement, and the dropping amount of pure water is 2 microliters.
Measure five times and adopt the average value of 3 points excluding the maximum and minimum values.
The measurement environment is a temperature of 23 ° C. and a relative humidity of 55%.

[Application example of coating equipment]
In the coating apparatus of the present invention, the type of the coating solution is not limited, and can be applied to apply a known coating solution. In particular, the coating apparatus of the present invention is suitable for coating an aqueous coating solution.

  Since the aqueous coating solution tends to wet and spread on the outer surface 12b of the most downstream lip 12 when coated with a slit die coating apparatus, the coating apparatus of the present invention that can suppress the wetting spread is effective.

  The aqueous coating solution means a coating solution containing water as a main component (including 50% by mass or more, further 60% by mass or more of water with respect to the total solvent) as a solvent or a dispersion medium. The aqueous coating solution can contain a solvent other than water, such as a water-soluble alcohol (lower alcohol).

  Examples of the aqueous coating solution include a coating solution containing a conductive linear structure (for example, carbon nanotube, silver nanowire, etc.), a coating solution in which organic or inorganic particles are dispersed, and a water-soluble polymer. Examples thereof include a coating solution and a coating solution containing an aqueous dispersion (emulsion etc.) of a hydrophobic polymer.

  The coating apparatus according to the present invention is suitable for thin film coating. For example, it is suitable for thin film coating having a wet film thickness of 30 μm or less, and further 20 μm or less. The lower limit wet film thickness is about 3 μm.

  In the thin film coating using the slit die coating apparatus, the stability of the beads is lower than that in the thick film coating, and the outer surface 12b of the most downstream lip 12 tends to wet and spread. It can suppress by using this coating device.

  The coating apparatus of the present invention is suitable for coating a low-viscosity coating liquid. For example, it is suitable for application of a coating solution having a viscosity at 23 ° C. of 30 mPa · s or less, and further 20 mPa · s or less. The lower limit viscosity is about 0.5 mPa · s. Here, the viscosity of the coating solution is measured with a B-type viscometer (Brookfield viscometer) at a coating solution temperature of 23 ° C.

  When applying a low-viscosity coating liquid with a slit die coating apparatus, the stability of the bead is lower than when applying a high-viscosity coating liquid, and it tends to wet and spread on the outer surface 12b of the most downstream lip 12, This wetting and spreading can be suppressed by using the coating apparatus of the present invention.

[Base material]
In the coating apparatus of the present invention, the type of the substrate to which the coating liquid is applied is not limited, and can be applied to a known substrate.
Examples of such a substrate include paper, plastic film, glass, metal foil, and composites thereof. The thickness of the substrate is suitably in the range of 20 to 300 μm. Among the above-mentioned base materials, a plastic film that is flexible, has a relatively high strength, and has a relatively good thickness accuracy in the width direction is preferable.

  Examples of the resin constituting the plastic film include polyester resins such as polyethylene terephthalate and polyethylene naphthalate, cellulose resins such as triacetyl cellulose, polyolefin resins such as polyethylene, polypropylene, and polybutylene, acrylic resins, and polycarbonate resins such as Arton (registered trademark). Heat-resistant transparent resin such as epoxy resin, polyimide resin, polyetherimide resin, polyamide resin, polysulfone resin, polyphenylene sulfide resin, and polyether sulfone resin.

[Manufacture of laminated film]
Various laminated films can be manufactured by using the coating apparatus of the present invention, the above-described coating method, and the substrate. For example, laminated films such as a conductive film, a hard coat film, an antireflection film, an antiglare film, an antistatic film, a self-repairing film, an adhesive film, and a release film can be produced.

  These laminated films are produced by applying and laminating various functional layers on a base material in one or more layers. The functional layer may be a layer having a function suitable for various functional films as described above. Examples of the functional layer include a conductive layer, a hard coat layer, an antireflection layer, an antistatic layer, a self-healing layer, an adhesive layer, and a release layer.

10 Slit die
11 Most upstream lip 11a Tip surface 11b Outer surface
11c Upstream side tip portion 12 Most downstream side lip 12a Tip side surface 12b Outer side surface 13 Coating liquid discharge slit
14 Central lip 20 Pressure reducing unit
21 Decompression chamber 30 Base material 40 Bead
40a upstream meniscus

Claims (13)

A coating apparatus provided with a slit die, wherein the slit die (10) has at least one coating liquid discharge slit (13), a most upstream lip (11), and a most downstream lip (12), The angle (θ ₁ ) formed by the tip surface (12a) and the outer surface (12b) of the most downstream lip (12) is less than 90 degrees, and the outer surface (12b) is coated with a water repellent film. A coating apparatus characterized by comprising:   The coating device according to claim 1, wherein the outermost surface (11b) of the most upstream lip (11) is covered with a water repellent film.   The coating apparatus according to claim 1, wherein the water repellent film is a carbon film.   The coating apparatus according to claim 3, wherein the carbon film is a DLC film.   The coating apparatus according to claim 4, wherein the DLC film is a fluorinated DLC film. The coating device according to any one of claims 1 to 5, wherein an angle (θ ₂ ) formed by a tip surface (11a) and an outer surface (11b) of the most upstream lip (11) is less than 90 degrees.   The coating device according to any one of claims 1 to 6, wherein a distal end surface (11a) of the most upstream lip (11) is covered with a hydrophilic film.   The coating apparatus according to claim 7, wherein the hydrophilic film is a hydrophilic DLC film.   The coating apparatus according to claim 1, further comprising a decompression unit upstream of the slit die.   The coating method of apply | coating a water-system coating liquid to a base material using the coating device in any one of Claims 1-9.   The coating method which apply | coats the coating liquid whose viscosity in 23 degreeC is 30 mPa * s or less to a base material with a wet film thickness of 30 micrometers or less using the coating device in any one of Claims 1-9. The manufacturing method of a laminated | multilayer film which apply | coats a coating liquid to a base material using the coating device in any one of Claims 1-9, and obtains a laminated | multilayer film. The manufacturing method of a laminated | multilayer film which apply | coats a coating liquid to a base material using the coating method of Claim 10 or 11, and obtains a laminated | multilayer film.

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