TW202227271A - Method for producing film - Google Patents

Abstract

A method for producing a film F comprises a coating step for coating a coating liquid on a substrate S using a bar 11, and a drying step for drying the coating liquid that has been coated on the substrate S. The coating liquid comprises a resin component, fine particles, and a dispersion medium that disperses the resin component and fine particles. The surface free energy of the bar 11 is higher than the surface tension of the coating liquid.

Description

Manufacturing method of thin film

The present invention relates to a method for manufacturing a thin film.

Conventionally, a method for producing a thin film is known in which a coating liquid containing fine particles, a resin component and a dispersion medium is applied to a substrate to form a film containing fine particles on the surface of the substrate (for example, see Patent Document 1). prior art literature Patent Literature

Patent Document 1: Japanese Patent Laid-Open No. 2020-23170

The problem to be solved by the invention According to the method described in the above-mentioned Patent Document 1, it is desirable to uniformly apply a coating liquid containing fine particles on a substrate.

The present invention provides a method for producing a thin film, which can uniformly coat a coating liquid containing fine particles on a substrate.

means of solving problems The present invention [1] includes a method for producing a thin film, comprising the steps of: a coating step of applying a coating liquid to a substrate using a coating member; and a drying step of applying the coating solution on the substrate The coating solution is dried; the coating solution contains fine particles, a resin component, and a dispersion medium for dispersing the fine particles and the resin component; the surface free energy of the coating member is higher than the surface tension of the coating solution.

The present invention [2] includes the method for producing a thin film according to the above [1], wherein the surface free energy of the coating member is 40 mJ/m ² or more.

The present invention [3] includes the method for producing a thin film according to the above [1] or [2], wherein the coating member is a roller.

The present invention [4] includes the method for producing a thin film according to any one of the above [1] to [3], wherein the coating member is coated with diamond-like carbon.

The present invention [5] includes the method for producing a thin film according to any one of the above [1] to [4], wherein the difference between the surface free energy of the coating member and the surface tension of the coating liquid is 14 mN/m or more .

Invention effect According to the method for producing the film of the present invention, the surface free energy of the coating member is higher than the surface tension of the coating liquid, so that the coating member is easily wetted by the coating liquid.

Therefore, even when the coating liquid contains fine particles, the coating liquid can be uniformly coated on the substrate.

1. Film manufacturing system The manufacturing system 1 of the thin film F is demonstrated.

As shown in FIG. 1 , the thin film F includes a base material S and a coating film C. As shown in FIG. The base material S has a first surface S1 and a second surface S2 in the thickness direction of the base material S. As shown in FIG. The film C is arranged on the first surface S1 of the substrate S. The film C covers the first surface S1 of the substrate S. The film C may also be an easily adhesive layer. When the coating film C is an easily bonding layer, the film F is an easily bonding film. The easy-to-bond film is used, for example, as a polarizer for image display devices such as mobile devices, car navigation devices, personal computer screens, and televisions. Specifically, the easily adhesive film is used as a protective film for protecting the polarizer of a polarizing plate. The easily adhesive film is bonded to the polarizer through the adhesive layer. The easily bonding film is bonded to the polarizer using the easily bonding layer.

As shown in FIG. 2, the production system 1 of the film F includes: an extrusion forming apparatus 2, a first stretching apparatus 4A, a bar coater 3 as an example of a coating apparatus, a second stretching apparatus 4B, a slitting processing apparatus 5, The knurl forming processing device 6 and the winding device 7 are provided.

(1) Extrusion forming device The extrusion forming apparatus 2 is used to extrude the base material S (extrusion forming step). The substrate S extruded from the extrusion forming apparatus 2 has a sheet shape.

The base material S is made of thermoplastic resin. The thermoplastic resins include, for example, acrylic resins, polyolefin resins, cyclic polyolefin resins, polyester resins, polycarbonate resins, polystyrene resins, polyamide resins, polyimide resins, acetate resins (diacetic acid cellulose, cellulose triacetate, etc.), etc.

In the production of an easily bonding film used as a protective film of a polarizer, the material of the substrate S is preferably an acrylic resin.

Moreover, when manufacturing an easily bonding film used as a protective film of a polarizer, the acrylic resin may be an acrylic resin having a glutaric anhydride structure, or an acrylic resin having a lactone ring structure. Acrylic resins with a glutaric anhydride structure and acrylic resins with a lactone ring structure have high heat resistance, high transparency, and high mechanical strength, and are therefore suitable for producing polarizing plates with high degrees of polarization and excellent durability. The acrylic resin system which has a glutaric anhydride structure is described in Unexamined-Japanese-Patent No. 2006-283013, Unexamined-Japanese-Patent No. 2006-335902, and Unexamined-Japanese-Patent No. 2006-274118. Acrylic resins having a lactone ring structure are described in Japanese Patent Laid-Open No. 2000-230016, Japanese Patent Laid-Open No. 2001-151814, Japanese Patent Laid-Open No. 2002-120326, and Japanese Patent Laid-Open No. 2002-254544 , Japanese Patent Laid-Open No. 2005-146084.

In addition, the base material S may contain other thermoplastic resins other than the acrylic resin in addition to the acrylic resin. By containing other thermoplastic resins, the birefringence of the acrylic resin can be eliminated to obtain an easy-bonding film with excellent optical isotropy. Moreover, the mechanical strength of the easy-to-bond film can also be improved.

In addition, the substrate S may also contain additives such as antioxidants, stabilizers, reinforcing materials, ultraviolet absorbers, flame retardants, antistatic agents, colorants, fillers, plasticizers, lubricants, and fillers.

(2) The first extension device The first extending device 4A is used to extend the substrate S in the traveling direction MD of the substrate S after heating (a first extending step).

(3) Bar coater The bar coater 3 applies the coating liquid to the first surface S1 of the base material S using the roller 11 (refer to FIG. 3 ) as an example of the coating member (coating step). The roller bar 11 will be explained later. In addition, on the first surface S1 of the substrate S, surface treatments such as corona treatment and plasma treatment may also be performed after the extrusion forming step and before the coating step.

(4) Second extension device The second stretching device 4B is used to dry the coating liquid applied on the substrate S (drying step). Thereby, the coating liquid becomes the coating film C described above. And the 2nd extending|stretching apparatus 4B is used for extending|stretching the base material S on which the film C was formed in the width direction TD of the base material S after heating (2nd extending|stretching process). The width direction TD is orthogonal to the traveling direction MD. By the second stretching step, the substrate S on which the coating film C is formed is stretched, and the above-mentioned thin film F can be obtained.

(5) Slitting processing device The slitting processing device 5 is used to cut the film F into a predetermined width (slitting step).

(6) Knurling processing device The knurling processing device 6 is used to form knurling on both ends in the width direction of the film F cut into a predetermined width (knurling forming step). The knurling is formed by laser. Knurling can also be formed by heated embossing rolls.

(7) Coiling device The winding device 7 is for winding the film F formed with the knurling (winding step). By completing the winding step, a roll of the film F can be obtained.

2. Details of the coating solution The coating liquid is an easily bonding composition for forming an easily bonding layer when producing an easily bonding film.

The easy-bond layer contains a binder resin and fine particles.

As a binder resin, a thermosetting resin and a thermoplastic resin are mentioned, for example. As a thermosetting resin, a urethane resin and an epoxy resin are mentioned, for example. Examples of thermoplastic resins include acrylic resins and polyester resins. When the easy-adhesive film is used as a protective film for the polarizer, the adhesive resin is preferably a thermosetting resin. A plurality of binder resins can be used in combination.

Examples of fine particles include oxides, carbonates, silicates, silicate minerals, and phosphates. As an oxide, silicon oxide (silica), titanium oxide (titania), aluminum oxide (alumina), and zirconia (zirconia) are mentioned, for example. The carbonate may, for example, be calcium carbonate. The silicate may, for example, be calcium silicate, aluminum silicate, and magnesium silicate. The silicate minerals include, for example, talc and kaolin. As a phosphate, calcium phosphate is mentioned, for example. When the easy-adhesive film is used as a protective film for the polarizer, the fine particles are preferably oxide, preferably silicon oxide. A plurality of fine particles can be used in combination.

The average primary particle size of the fine particles is smaller than the thickness of the coating film C, for example. Since the average primary particle size of the fine particles is smaller than the thickness of the film C, the fine particles can be suppressed from falling off from the film C. The average primary particle size of the fine particles is, for example, 200 nm or less, preferably 150 nm or less, more preferably 100 nm or less, more preferably 80 nm or less, more preferably 60 nm or less, and more preferably 50 nm or less.

The average primary particle diameter of the fine particles is, for example, 10 nm or more, preferably 15 nm or more, and more preferably 20 nm or more. When the average primary particle size of the fine particles is at least the above lower limit value, when the film F is wound up, sticking can be suppressed.

The refractive index of the fine particles is preferably close to the refractive index of the substrate S. When the base material S is an acrylic resin, the refractive index of the fine particles is, for example, less than 1.5.

The coating liquid (easy-bonding composition) contains a resin component, the above-mentioned fine particles, and a dispersion medium. The coating liquid contains additives as needed. As an additive, a crosslinking agent and a pH adjuster are mentioned, for example.

The resin component forms the coating film of the above-mentioned binder resin by the drying step. When the binder resin is a urethane resin, the resin component includes, for example, a water-based urethane resin. The water-based urethane resin includes, for example, a non-reactive water-based urethane resin and a reactive water-based urethane resin. Non-reactive water-based urethane resin is an emulsion of urethane resin. The reactive water-based urethane resin is an emulsion of the urethane resin in which the isocyanate group is protected by a blocking agent. When the binder resin is a urethane resin, the coating liquid may contain a urethane curing catalyst and an isocyanate monomer. As a urethane hardening catalyst, triethylamine is mentioned, for example.

The blend ratio of the resin component is, in terms of solid content, in the coating liquid, for example, 3 mass % or more, preferably 5 mass % or more, and more preferably 7 mass % or more. When the compounding ratio of a resin component is more than the said lower limit, the drying time of a coating liquid can be shortened.

The blend ratio of the resin component is, in terms of solid content, in the coating liquid, for example, 20% by mass or less, preferably 15% by mass or less. When the blending ratio of the resin component is at most the above upper limit value, the resin component can be stably dispersed in the coating liquid.

The blending ratio of the fine particles is, in terms of solid content, for example, 30 parts by mass or more, preferably 50 parts by mass or more, with respect to 100 parts by mass of the resin component. When the mixing ratio of the fine particles is at least the above lower limit value, the drying time of the coating liquid can be shortened.

The mixing ratio of the fine particles is, in terms of solid content, for example, 150 parts by mass or less, preferably 120 parts by mass or less, preferably 90 parts by mass or less, relative to 100 parts by mass of the resin component. When the mixing ratio of the fine particles is equal to or less than the above upper limit value, the fine particles can be stably dispersed in the coating liquid.

In addition, the mixing ratio of the fine particles in the coating liquid is, for example, 1 mass % or more, preferably 5 mass % or more, and, for example, 10 mass % or less.

The dispersion medium is used to disperse the fine particles and the resin component. Examples of the dispersion medium include water, alcohol, and ketone. Examples of alcohols include methanol and ethanol. Examples of ketones include acetone and methyl ethyl ketone.

The dispersion medium is blended in the coating liquid as the remainder other than the resin component, fine particles, and additives. The mixing ratio of the dispersion medium in the coating liquid is, for example, 30 mass % or more, preferably 40 mass % or more, and, for example, 80 mass % or less, preferably 70 mass % or less, and more preferably 60 mass % or less.

The crosslinking agent is used to crosslink the resin component in the drying step and the second stretching step. When the resin component is an aqueous urethane resin, the crosslinking agent includes, for example, a thermosetting crosslinking agent. Examples of the thermosetting crosslinking agent include oxazoline group-containing polymers and isocyanate group-containing polymers.

The blending ratio of the crosslinking agent is, in terms of solid content, for example, 5 parts by mass or more, preferably 10 parts by mass or more, and for example, 30 parts by mass or less with respect to 100 parts by mass of the resin component.

The pH adjuster is used to adjust the pH of the coating solution. Well-known acids and bases are mentioned as pH adjusters.

The pH of the coating liquid is, for example, 7.5 or more. When the pH of the coating liquid is at least the above lower limit value, the occurrence of aggregates can be suppressed. In addition, the pH of the coating liquid is, for example, 9.0 or less. If the pH of the coating liquid is below the above-mentioned upper limit value, it is possible to suppress the decrease in the heat and humidity resistance of the polarizing plate.

As long as the wettability of the coating liquid to the substrate S can be ensured, the surface tension of the coating liquid is not limited. When the base material S is an acrylic resin, the surface tension of the coating liquid is, for example, 30 mN/m or more, preferably 40 mN/m or more, and, for example, 80 mN/m or less, preferably 70 mN/m or less, more preferably 60 mN/m or less , more preferably below 50mN/m. By adjusting the mixing ratio of the resin component and the dispersion medium, the surface tension of the coating liquid can be adjusted.

The surface tension of the coating liquid can be measured by the method described in the examples described later.

3. Details of the rod coater As shown in FIG. 3 , the bar coater 3 includes a roll bar 11 and a manifold block 12 as an example of a supply device.

(1) Roller The roller 11 is used for coating the coating liquid on the substrate S in the above coating step. The rollers 11 extend in the axial direction. The axial direction is the same direction as the width direction TD of the substrate S. That is, the axial direction is orthogonal to the advancing direction MD of the base material S. As shown in FIG. The roller bar 11 is arranged on the upper end of the bar coater 3 . In other words, the roller bar 11 is arranged at one end of the bar coater 3 in the orthogonal direction to both the axial direction and the advancing direction MD. The roller 11 has a cylindrical shape.

The roller bar 11 may be, for example, a wire bar or a cordless bar. The wire rod has a shaft and a wire wound on the shaft. The wire rod has grooves formed between the wires in the axial direction. The wireless rod has grooves on the surface.

The surface free energy of the roller 11 is higher than the surface tension of the coating liquid. Therefore, the roller 11 is easily wetted by the coating liquid. Therefore, even when the coating liquid contains fine particles, the coating liquid can be uniformly coated on the substrate S in the width direction.

Specifically, the surface free energy of the rolling rod 11 is 40 mJ/m ² or more, preferably 50 mJ/m ² or more, preferably 70 mJ/m ² or more, and more preferably 90 mJ/m ² or more. The upper limit of the surface free energy of the rolling rod 11 is not limited. The surface free energy of the roller 11 is, for example, 150 mJ/m ² or less.

The surface free energy of the rolling rod 11 can be measured by the method described in the following examples.

The difference between the surface free energy of the roller 11 and the surface tension of the coating liquid is, for example, 10 mN/m or more, preferably 14 mN/m or more, more preferably 20 mN/m or more, more preferably 35 mN/m or more, more preferably 50 mN /m or more. When the difference between the surface free energy of the roller 11 and the surface tension of the coating liquid is equal to or more than the above lower limit value, the coating liquid can be applied to the substrate S more uniformly. The upper limit of the difference between the surface free energy of the roller 11 and the surface tension of the coating liquid is not limited.

It is preferable to apply surface treatment to the rolling rod 11 . The surface treatment includes, for example, hard chromium (HCr) plating, diamond-like carbon (DLC) coating, and titanium coating (titanium nitride coating). The rolling rod 11 should preferably be coated with diamond-like carbon. By performing surface treatment on the roller 11, the surface free energy of the roller 11 is increased, so that the roller 11 is more easily wetted by the coating liquid. Therefore, the coating liquid can be applied to the base material S more uniformly.

It is preferable to perform micro-dimple treatment on the roller bar 11 in addition to the above-mentioned surface treatment. The surface free energy of the rolling rod 11 is further increased by performing the micro-dimple treatment on the rolling rod 11, so that the rolling rod 11 is more easily wetted by the coating liquid. Therefore, the coating liquid can be applied to the substrate S more uniformly.

The diameter of the roller 11 is, for example, 5 mm (φ5) or more, preferably 8 mm or more. If the diameter of the rolling rod 11 is more than the above lower limit value, the rigidity of the rolling rod 11 can be ensured. Thereby, the roller 11 can resist the tension of the substrate S, and can stably coat the coating liquid on the substrate S. The diameter of the roller 11 is, for example, 10 mm (φ10) or less. If the diameter of the roller 11 is below the above-mentioned upper limit value, the coating liquid can be easily supplied to the entire surface of the roller 11, and the coating liquid can be applied to the substrate S stably.

The rollers 11 rotate in the forward direction with respect to the traveling direction MD (see arrows in FIG. 3 ). The rotation speed of the roller 11 is faster than the conveying speed of the substrate S. Thereby, when the substrate S is conveyed in the traveling direction MD and the roller 11 is rotating, a coating liquid is formed between the roller 11 and the substrate S on the upstream side of the roller 11 in the traveling direction MD. The accumulated liquid L.

In the case of the accumulated liquid L, the accumulated coating liquid is stirred by the speed difference between the rotational speed of the roller 11 and the conveyance speed of the substrate S. Thereby, a shearing force is applied to the coating liquid of the accumulated liquid L. When the coating liquid contains a cross-linking agent, the resin component and the cross-linking agent may react with the shearing force, and aggregates may be generated.

Based on this, if the surface free energy of the roller 11 is higher than the surface tension of the coating liquid, the roller 11 is easily wetted by the coating liquid, so that the shear force applied to the coating liquid in the accumulation liquid L can be reduced. Therefore, the reaction of the resin component and the crosslinking agent can be suppressed. As a result, the production of aggregates can be suppressed.

The rotational speed of the rollers 11 is, for example, 100% or more, preferably 120% or more, for example, 200% or less, preferably 180% or less, relative to the conveyance speed of the substrate S.

(2) Manifold block The branch pipe 12 is used to supply the coating liquid to the roller 11 . The manifold block 12 is arranged below the roller bar 11 . In a state where the bar coater 3 is applying the coating liquid to the substrate S, the manifold block 12 is arranged on the opposite side of the roller bar 11 with respect to the substrate S in the orthogonal direction. The manifold block 12 is used to support the rollers 11 . The manifold block 12 extends in the axial direction and the orthogonal direction. The manifold block 12 has a manifold 121 , a discharge port 122 and a flow path 123 .

(2-1) Manifold The manifold 121 is disposed away from the rollers 11 in the orthogonal direction. The manifold 121 stores the coating liquid.

(2-2) Discharge port The discharge port 122 is disposed at one end portion in the orthogonal direction of the manifold block 12 . The discharge port 122 is arranged on the upstream side of the roller 11 in the traveling direction MD. The discharge port 122 discharges the coating liquid. The coating liquid discharged from the discharge port 122 is supplied to the roller 11 . The coating liquid supplied to the roller 11 is coated on the substrate S by the rotation of the roller 11 .

(2-3) Flow path The flow path 123 is arranged between the manifold 121 and the discharge port 122 in the orthogonal direction. The flow path 123 connects the manifold 121 and the discharge port 122 . The coating liquid in the manifold 121 is discharged from the discharge port 122 through the flow path 123 .

3. Variations (1) The use of the bar coater 3 is not limited to extrusion molding. For example, the base material S may be released from the coil of the base material S, and the coating liquid may be applied to the released base material S by the bar coater 3 .

(2) The coating device is not limited to the bar coater 3 . For example, the coating apparatus includes a gravure coater and a contact coater.

(3) Coating Apparatus As shown in FIG. 4 , instead of the manifold block 12 , a disk 31 for accumulating the coating liquid may be provided as an example of the supplying apparatus.

(4) The production system 1 of the film F may not include the first stretching device 4A. The base material S to which the coating liquid is applied may be stretched in the traveling direction MD and the width direction TD by the second stretching device 4B (biaxial simultaneous stretching). The manufacturing system 1 of the film F may not extend the substrate S. That is, the manufacturing system 1 of the film F may not include the first stretching device 4A and the second stretching device 4B.

(5) The manufacturing system 1 of the film F may also be provided with a masking film releasing device and a laminating device instead of the knurling forming processing device 6. The masking film releasing device is used to release the masking film, and the laminating device It is used to attach the released masking film to the film F.

Example Next, this invention is demonstrated based on an Example and a comparative example. The present invention is not limited by the following examples. In addition, specific numerical values such as physical property values and parameters used in the description below may be substituted with the upper limit values of the physical property values, parameters, etc. corresponding to those described in the above-mentioned "Forms for Carrying Out the Invention" (the numerical values defined by "the following") or the lower limit (value as defined by "above").

1. Preparation of coating solution (1) Coating liquid A Aqueous urethane resin (solid content: 35 mass %) 35.2 mass parts, silica fine particles 7.5 mass parts, crosslinking agent (oxazoline group-containing polymer, solid content: 25 mass %) 5.2 mass parts, Coating liquid A was obtained by mixing 2.8 parts by mass of 1% ammonia water and 49.3 parts by mass of pure water.

The surface tension of the coating liquid A was 40 mN/m. In addition, the surface tension of the coating liquid A was measured by the pendant drop method using a contact angle meter.

(2) Coating liquid B Coating liquid B was obtained in the same manner as coating liquid A, except that the mixing part of the aqueous urethane resin was changed to 20.6 parts by mass and the mixing part of pure water was changed to 63.9 parts by mass.

The surface tension of the coating liquid B was 55 mN/m.

(3) Coating liquid C Coating liquid C was obtained in the same manner as coating liquid A, except that the blending parts of the aqueous urethane resin were changed to 12.8 parts by mass and the blending parts of pure water were changed to 71.7 parts by mass.

The surface tension of the coating liquid C was 70 mN/m.

2. Examples and Comparative Examples (1) Example 1 The coating liquid A (surface tension: 40 mN/m) was apply|coated to the base material which consists of acrylic resins using the coating apparatus provided with the roller bar with surface treatment as described in Table 1, and it dried to obtain a film.

In addition, in Table 1, "DLC" means diamond-like carbon coating. The surface free energy of the roller was calculated from the measured value using a contact angle meter by a theoretical formula (kitazaki and hata).

The variation in coating thickness and the number of aggregates were measured for the obtained film. The variation in coating thickness and the number of aggregates were measured using a spectroscopic film thickness meter (MCPD, manufactured by Otsuka Electronics Co., Ltd.). The results are shown in Table 1.

(2) Examples 2 to 7, Comparative Examples 1 to 11 Using the coating apparatus described in Tables 1 to 3, which is equipped with a roller bar with surface treatment, the coating liquids described in Tables 1 to 3 were applied to a base material composed of acrylic resin in the same manner as in Example 1, and dried. to obtain a thin film.

The variation in coating thickness and the number of aggregates were measured for the obtained film. The results are described in Tables 1 to 3.

In addition, in Table 2, "HCr" means hard chrome plating. In Table 3, "titanium" refers to titanium coating.

[Table 1]

[Table 2]

此外，上述發明雖提供作為本發明例示之實施形態，但僅為例示，不得作限定解釋。該技術領域之熟知此項技藝之人士明瞭可知本發明變形例包含於後述申請專利範圍中。 產業上之可利用性 本發明薄膜之製造方法係利用於製造易接著薄膜等薄膜。 [table 3]

In addition, although the above-mentioned invention provides the embodiment as an example of this invention, it is only an illustration, and should not be construed as a limitation. It will be apparent to those skilled in the art that modifications of the present invention are included in the scope of the patent application described later. INDUSTRIAL APPLICATION The manufacturing method of the thin film of this invention is utilized for manufacturing thin films, such as an easily bonding film.

1: Film manufacturing system 2: Extrusion forming device 3: Bar coater 4A: 1st extension device 4B: 2nd extension device 5: Slitting processing device 6: Knurling processing device 7: Coiling device 11: Roller 12: Manifold block 31: Plates 121: Manifold 122: Spit out 123: Flow Path C: film F: film L: accumulating fluid S: Substrate S1: Side 1 S2: Side 2

FIG. 1 is a cross-sectional view of a film produced by a film production system as an embodiment of the present invention. FIG. 2 is a schematic configuration diagram of a thin film manufacturing system. FIG. 3 is an explanatory diagram for explaining the bar coater shown in FIG. 2 . FIG. 4 is an explanatory diagram for explaining a modification of the bar coater.

11: Roller

12: Manifold block

121: Manifold

122: Spit out

123: Flow Path

L: accumulating fluid

S: Substrate

Claims (5)

A method for manufacturing a thin film, comprising the following steps: The coating step is to use the coating member to coat the coating liquid on the substrate; and The drying step is to dry the coating liquid coated on the substrate; The coating liquid contains a resin component, fine particles, and a dispersion medium for dispersing the resin component and the fine particles; The surface free energy of the coating member is higher than the surface tension of the coating liquid. The method for producing a thin film according to claim 1, wherein the surface free energy of the coating member is 40 mJ/m ² or more. The method for producing a film according to claim 1 or claim 2, wherein the coating member is a roller. The method for producing a thin film according to any one of claims 1 to 3, wherein the aforementioned coating member is coated with diamond-like carbon. The method for producing a thin film according to any one of Claims 1 to 4, wherein the difference between the surface free energy of the coating member and the surface tension of the coating liquid is 14 mN/m or more.

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