Method for producing film

Abstract

Provided is a method for producing a film, which is a method for forming a coating film having a width of 1600 mm or more and a thickness of 30 [mu] m or less on a substrate using a slit die, the method comprising: an application step for applying an application liquid to the substrate; and a drying step for drying the coating liquid applied to the base material. The thickness of the pad of the slit die is 20 [mu] m or more and 100 [mu] m or less.

Description

Technical Field

[0001] The present invention relates to a method for producing a film. Background Art

[0002] Conventionally, there is known a method for producing a film in which a coating liquid is applied onto a substrate using a slot die coater (for example, see Patent Document 1).

[0003] Prior art literature

[0004] Patent Literature

[0005] Patent Document 1: Japanese Patent Application Publication No. 2021-34139 Summary of the invention

[0006] Problems to be solved by the invention

[0007] In the film production method described in Patent Document 1, when a wide and thin film is formed on a substrate, it is desired to form the film more uniformly.

[0008] The present invention provides a method for producing a film capable of uniformly forming a wide and thin film on a substrate using a slot die.

[0009] Solutions to the problem

[0010] The present invention [1] includes a method for manufacturing a film, which is a method for forming a film having a width of 1600 mm or more and a thickness of 30 μm or less on a substrate using a slit die, the method comprising: a coating step of coating a coating liquid on the substrate; and a drying step of drying the coating liquid coated on the substrate, wherein the thickness of the gasket of the slit die is 20 μm or more and 100 μm or less.

[0011] The present invention [2] includes a method for manufacturing the film of the above-mentioned [1], wherein the above-mentioned slit die head comprises a first block, a second block, and the above-mentioned gasket, the above-mentioned second block is arranged on the downstream side of the conveying direction of the above-mentioned substrate compared to the above-mentioned first block, and a slit is formed between the above-mentioned first block and the above-mentioned second block, the above-mentioned gasket is arranged between the above-mentioned first block and the above-mentioned second block, the above-mentioned second block has a main body, and a protrusion protruding from the end face on the downstream side of the above-mentioned main body toward the downstream side of the above-mentioned ejection direction in the ejection direction of the above-mentioned coating liquid, and the protrusion amount of the above-mentioned protrusion is less than 10μm.

[0012] The present invention [3] includes a method for manufacturing the film of the above-mentioned [1], wherein the above-mentioned slit die comprises a first block, a second block, and the above-mentioned gasket, the above-mentioned second block is arranged on the downstream side of the above-mentioned first block in the conveying direction of the above-mentioned substrate and forms a slit between the above-mentioned first block and the above-mentioned first block, the above-mentioned gasket is arranged between the above-mentioned first block and the above-mentioned second block, the above-mentioned second block has an inclined surface, and the inclined surface is inclined in a direction away from the above-mentioned first block as the above-mentioned second block moves from the downstream end of the above-mentioned second block in the ejection direction of the above-mentioned coating liquid toward the upstream end of the above-mentioned second block in the above-mentioned ejection direction, and the obtuse angle formed by the ejection direction of the above-mentioned coating liquid and the above-mentioned inclined surface is greater than 110° and less than 170°.

[0013] The present invention [4] includes the method for producing a film according to [1] above, wherein the conveyance speed of the substrate is 15 m / min or more and 30 m / min or less.

[0014] The present invention [5] includes the method for producing a film according to [1] above, wherein the coating liquid has a solid content concentration of 10% by mass or more and 50% by mass or less.

[0015] The present invention [6] includes a method for producing the film of the above-mentioned [1], wherein the above-mentioned coating liquid contains a polyfunctional oligomer and a trifunctional monomer, the proportion of the above-mentioned polyfunctional oligomer in the above-mentioned coating liquid is greater than 20% by mass and less than 70% by mass, and the proportion of the above-mentioned trifunctional monomer in the above-mentioned coating liquid is greater than 20% by mass and less than 70% by mass.

[0016] The present invention [7] includes the method for producing a film according to [1] above, wherein the elastic modulus of the gasket is 1500 MPa or more and 6000 MPa or less.

[0017] The present invention [8] includes the method for producing a film according to [1] above, wherein the spacer is made of polyethylene terephthalate.

[0018] Effects of the Invention

[0019] According to the film production method of the present invention, the thickness of the spacer of the slot die is adjusted to be 30 μm or more and 100 μm or less.

[0020] Therefore, a wide (width of 1600 mm or more) and thin (thickness of 30 μm or less) film can be uniformly formed on the substrate. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 is a cross-sectional view of the membrane.

[0022] Figure 2 This is a schematic diagram of the membrane manufacturing system.

[0023] Figure 3It is a three-dimensional diagram of a slot die.

[0024] Figure 4 yes Figure 3 A cross-sectional view of a slot die is shown.

[0025] Explanation of symbols

[0026] D Slot Die

[0027] 10 Slit

[0028] 11 Block 1

[0029] 12 Block 2

[0030] 13 Gasket DETAILED DESCRIPTION

[0031] 1. Film manufacturing method

[0032] In the method for producing the film F of the present invention, a "wide" and "thin" film C is formed on a substrate S using a slot die D. "Wide" means a width of 1600 mm or more. "Thin" means a thickness of 30 μm or less.

[0033] (1) Membrane

[0034] First, the film F will be described. Figure 1 As shown, the film F includes a substrate S and a coating C.

[0035] The substrate S has a sheet shape. The substrate S has a first surface S1 and a second surface S2 in the thickness direction of the substrate S. The substrate S is formed of a thermoplastic resin.

[0036] Examples of the thermoplastic resin include acrylic resins, polyolefin resins, cyclic polyolefin resins, polyester resins, polycarbonate resins, polystyrene resins, polyamide resins, polyimide resins, and acetate resins. Examples of the acetate resin include cellulose diacetate and cellulose triacetate.

[0037] The substrate S may contain additives. Examples of the additives include antioxidants, stabilizers, reinforcing materials, ultraviolet absorbers, flame retardants, antistatic agents, colorants, fillers, plasticizers, lubricants, and fillers.

[0038] The film C is disposed on the first surface S1 of the substrate S. The film C covers the first surface S1 of the substrate S. Examples of the function of the film C include anti-glare property, anti-reflection property, and scratch resistance.

[0039] The film C contains a resin. Examples of the resin include thermosetting resins and thermoplastic resins. Examples of the thermosetting resins include urethane resins and epoxy resins. Examples of the thermoplastic resins include acrylic resins, urethane acrylic resins, and polyester resins.

[0040] The film C may contain particles. Examples of particles include oxides, carbonates, silicates, silicate minerals, and phosphates. Examples of oxides include silicon oxide (silicon dioxide), titanium oxide (titania), aluminum oxide (alumina), and zirconium oxide (zirconium dioxide). Examples of carbonates include calcium carbonate. Examples of silicates include calcium silicate, aluminum silicate, and magnesium silicate. Examples of silicate minerals include talc and kaolin. Examples of phosphates include calcium phosphate.

[0041] (2) Membrane manufacturing system

[0042] Next, a film F manufacturing system 1 for implementing the film F manufacturing method will be described. Figure 2 As shown, a system 1 for producing a film F includes a coating device 2 having a slot die D and a drying device 3 .

[0043] The coating device 2 applies the coating liquid to the first surface S1 of the substrate S (coating step). That is, the method for manufacturing the film F includes a coating step. It should be noted that the first surface S1 of the substrate S may be subjected to a surface treatment such as a corona treatment or a plasma treatment before the coating step.

[0044] In the coating step, the conveying speed of the substrate S is, for example, 10 m / min or more, preferably 15 m / min or more, more preferably 20 m / min or more, for example, 40 m / min or less, preferably 35 m / min or less, more preferably 30 m / min or less.

[0045] When the conveyance speed of the substrate S is equal to or lower than the upper limit value, the coating liquid can be uniformly applied to the substrate S. When the conveyance speed of the substrate S is equal to or higher than the lower limit value, the production efficiency of the film F can be improved.

[0046] The drying device 3 dries the coating liquid applied to the substrate S (drying step). That is, the method for manufacturing the film F includes a drying step. By drying the coating liquid, a film C can be formed on the substrate S, thereby obtaining the above-mentioned film F. It should be noted that, as required, the film C can also be subjected to ultraviolet curing treatment or thermal curing treatment.

[0047] 2. Details of coating liquid

[0048] The viscosity of the coating liquid is, for example, 100 mPa·s or less, preferably 50 mPa·s or less, more preferably 10 mPa·s or less, for example, 1 mPa·s or more. When the viscosity of the coating liquid is below the upper limit, the coating liquid can be uniformly applied to the substrate S.

[0049] The surface tension of the coating liquid is, for example, 30 mN / m or more, preferably 35 mN / m or more, and for example, 60 mN / m or less, preferably 55 mN / m or less.

[0050] The solid content concentration of the coating liquid is adjusted so that the viscosity of the coating liquid is below the above upper limit. The solid content concentration of the coating liquid is, for example, 10% by mass or more, preferably 20% by mass or more, more preferably 30% by mass or more, more preferably 40% by mass or more, for example, 50% by mass or less, preferably 45% by mass or less.

[0051] The coating liquid contains a resin component and a solvent. The coating liquid contains the above-mentioned particles and additives as needed. The resin component may be the above-mentioned resin or a precursor of the above-mentioned resin.

[0052] Specifically, the coating liquid contains a polyfunctional oligomer, a polyfunctional monomer, a hydroxyl monomer, a photopolymerization initiator, the above-mentioned particles, a surface tension adjuster, and a thickener. The polyfunctional oligomer, the polyfunctional monomer, and the hydroxyl monomer are resin components (precursors of the resin), and the photopolymerization initiator, the surface tension adjuster, and the thickener are additives.

[0053] The polyfunctional oligomer has a plurality of ethylenically unsaturated groups. Examples of the ethylenically unsaturated group include an acryloyl group, a methacryloyl group, and a vinyl group.

[0054] The weight average molecular weight of the polyfunctional oligomer is, for example, 300 or more, preferably 400 or more, and for example, 5000 or less, preferably 3000 or less.

[0055] The functional group equivalent of the polyfunctional oligomer is, for example, 1 or more, preferably 2 or more, and for example, 6 or less, preferably 5 or less.

[0056] As a polyfunctional oligomer, a urethane acrylate and an erythritol type acrylate are mentioned, for example.

[0057] The proportion of the polyfunctional oligomer in the coating liquid is, for example, 20 mass % or more, preferably 30 mass % or more, and for example, 70 mass % or less, preferably 50 mass % or less.

[0058] The polyfunctional monomer has a plurality of ethylenically unsaturated groups. Examples of the ethylenically unsaturated group include an acryloyl group, a methacryloyl group, and a vinyl group.

[0059] As a polyfunctional monomer, the condensation product of pentaerythritol and acrylic acid is mentioned, for example.

[0060] The ratio of the polyfunctional monomer in the coating liquid is, for example, 20 mass % or more, preferably 30 mass % or more, and for example, 70 mass % or less, preferably 50 mass % or less.

[0061] The hydroxyl monomer has one ethylenically unsaturated group and one hydroxyl group. Examples of the hydroxyl monomer include 4-hydroxybutyl acrylate and 2-hydroxyethyl acrylate.

[0062] The photopolymerization initiator causes free radical polymerization of the polyfunctional oligomer, polyfunctional monomer, and hydroxyl monomer by ultraviolet irradiation. Examples of the photopolymerization initiator include benzophenone-based photopolymerization initiators, phosphine oxide-based photopolymerization initiators, oxime ester-based photopolymerization initiators, and cationic photopolymerization initiators.

[0063] The surface tension adjuster adjusts the surface tension of the coating liquid. Examples of the surface tension adjuster include cationic surfactants, anionic surfactants, nonionic surfactants, silicone-based leveling agents, and fluorine-based leveling agents.

[0064] The thickener adjusts the viscosity of the coating liquid and examples of the thickener include synthetic inorganic polymers, synthetic organic polymers, and natural organic polymers.

[0065] 3. Details of the slot die

[0066] like Figure 3 As shown, the slot die D includes a first block 11, a second block 12, and a spacer 13. The slot die D has a slit 10 between the first block 11 and the second block 12. The coating liquid is ejected from the slit 10.

[0067] (1) Block 1

[0068] The first block 11 is arranged on the upstream side of the second block 12 in the conveying direction of the substrate S. In the present embodiment, the first block 11 is arranged below the second block 12. The first block 11 extends in the width direction of the substrate S. Figure 4 As shown, the first block 11 has an upstream end E1 and a downstream end E2 in the discharge direction of the coating liquid. In addition, the first block 11 has a manifold 111 , a flow path 112 , a slit surface 113 , and an inclined surface 114 .

[0069] The manifold 111 is disposed between the upstream end E1 and the downstream end E2 in the discharge direction of the coating liquid. The manifold 111 extends in the width direction. The manifold 111 opens toward the second block 12 .

[0070] The flow path 112 is disposed in the center of the first block 11 in the width direction. The flow path 112 leads to the manifold 111. The coating liquid passes through the flow path 112 and enters the manifold 111.

[0071] The slit surface 113 is the inner surface of the upstream side of the slit 10 in the conveying direction of the substrate S. The slit surface 113 faces the second block 12. The slit surface 113 extends from the manifold 111 to the downstream end E2 in the ejection direction of the coating liquid. The slit surface 113 also extends in the width direction. The slit surface 113 is a flat surface.

[0072] The inclined surface 114 is an outer surface of the upstream side of the first block 11 in the conveying direction of the substrate S. The inclined surface 114 is inclined relative to the ejection direction of the coating liquid. Specifically, the inclined surface 114 is inclined in a direction away from the second block 12 as it moves from the downstream end E2 toward the upstream end E1 of the first block 11. The obtuse angle θ1 formed by the ejection direction of the coating liquid and the inclined surface 114 is, for example, 110° or more, preferably 140° or more, for example, 170° or less, preferably 160° or less.

[0073] When the obtuse angle θ1 is equal to or greater than the lower limit, it is possible to suppress excessive accumulation of the coating liquid on the upstream side of the protrusion 122 in the conveying direction of the substrate S. The protrusion 122 will be described later. When the obtuse angle θ1 is equal to or less than the upper limit, it is possible to suppress excessive accumulation of the coating liquid on the upstream side of the protrusion 122 in the conveying direction of the substrate S.

[0074] (2) Block 2

[0075] like Figure 3 As shown, the second block 12 is arranged on the downstream side compared to the first block 11 in the conveying direction of the substrate S. In this embodiment, the second block 12 is arranged above the first block 11. The second block 12 extends in the width direction of the substrate S. Figure 4 As shown in FIG. 1 , the second block 12 has an upstream end E11 and a downstream end E12 in the discharge direction of the coating liquid.

[0076] The main body 121 is the entire second block 12 except for the protruding portion 122. The main body 121 has a slit surface 1211, an inclined surface 1212, and an end surface 1213.

[0077] The slit surface 1211 is the inner surface of the downstream side of the slit 10 in the conveying direction of the substrate S. The slit surface 1211 is opposite to the first block 11. In detail, the slit surface 113 is opposite to the manifold 111 and the slit surface 113. The slit surface 1211 extends in the ejection direction of the coating liquid. The slit surface 1211 extends parallel to the slit surface 113. It should be noted that the slit surface 1211 also extends in the width direction. The slit surface 1211 is a flat surface.

[0078] The inclined surface 1212 is an outer surface of the downstream side of the second block 12 in the conveying direction of the substrate S. The inclined surface 1212 is inclined relative to the ejection direction of the coating liquid. In detail, the inclined surface 1212 is inclined in a direction away from the first block 11 as it moves from the downstream end E12 of the second block 12 toward the upstream end E11. The obtuse angle θ2 formed by the ejection direction of the coating liquid and the inclined surface 1212 is, for example, 110° or more, preferably 140° or more, for example, 170° or less, preferably 160° or less.

[0079] When the obtuse angle θ2 is equal to or greater than the lower limit, it is possible to prevent the coating liquid from being excessively accumulated on the upstream side of the protrusion 122 in the conveyance direction of the substrate S. When the obtuse angle θ2 is equal to or less than the upper limit, it is possible to prevent the amount of coating liquid accumulated on the upstream side of the protrusion 122 in the conveyance direction of the substrate S from being too small.

[0080] The end surface 1213 is an end surface on the downstream side of the main body 121 in the discharge direction of the coating liquid. The end surface 1213 is arranged at the downstream end E12 of the second block. The end surface 1213 is orthogonal to the slit surface 1211. The end surface 1213 extends in the conveyance direction of the substrate S.

[0081] The protrusion 122 protrudes toward the downstream side in the ejection direction relative to the end surface 1213. In other words, the protrusion 122 protrudes toward the substrate S.

[0082] The protrusion amount of the protrusion 122 is, for example, 15 μm or less, preferably 10 μm or less, preferably 5 μm or less, for example, 1 μm or more.

[0083] When the protrusion amount of the protrusion 122 is less than the above upper limit value, the contact between the protrusion 122 and the substrate S can be suppressed. When the protrusion amount of the protrusion 122 is greater than the above lower limit value, the coating liquid can be accumulated on the upstream side of the protrusion 122 in the conveying direction of the substrate S, and the coating liquid can be uniformly applied to the substrate S even if the conveying speed of the substrate S is increased.

[0084] The protrusion amount of the protrusion 122 relative to the distance between the end surface 1213 and the substrate S in the ejection direction is, for example, 20% or less, preferably 10% or less, for example, 1% or more.

[0085] When the ratio of the protrusion amount of the protrusion 122 relative to the distance between the end surface 1213 and the substrate S in the ejection direction is less than the upper limit value, the contact between the protrusion 122 and the substrate S can be suppressed. When the ratio of the protrusion amount of the protrusion 122 relative to the distance between the end surface 1213 and the substrate S in the ejection direction is greater than the lower limit value, the coating liquid can be accumulated on the upstream side of the protrusion 122 in the conveyance direction of the substrate S, and the coating liquid can be uniformly applied to the substrate S even if the conveyance speed of the substrate S is increased.

[0086] (3) Gasket

[0087] like Figure 3 and Figure 4 As shown, the spacer 13 is disposed between the first block 11 and the second block 12. The spacer 13 adjusts the distance between the slit surface 113 of the first block 11 and the slit surface 1211 of the second block 12. In other words, the spacer 13 adjusts the inner dimension of the slit 10 in the conveying direction of the substrate S.

[0088] The thickness of the spacer 13 is 20 μm or more, preferably 30 μm or more, more preferably 60 μm or more, and for example, 100 μm or less, preferably 80 μm or less.

[0089] When the thickness of the gasket 13 is greater than or equal to the lower limit, the thickness of the central portion of the film C in the width direction of the substrate S can be suppressed from excessively increasing relative to the thickness of the end portions of the film C in the width direction of the substrate S. When the thickness of the gasket 13 is less than or equal to the upper limit, the thickness of the end portions of the film C in the width direction of the substrate S can be suppressed from excessively increasing relative to the thickness of the central portion of the film C in the width direction of the substrate S.

[0090] Examples of the material of the gasket 13 include stainless steel and polyethylene terephthalate.

[0091] The elastic modulus of the gasket 13 is not less than 1500 MPa and not more than 6000 MPa. When the elastic modulus of the gasket 13 is below the above upper limit, the gasket 13 can be deformed only slightly when the gasket 13 is sandwiched between the first block 11 and the second block 12. As a result, the gasket 13 can be brought into contact with the first block 11 in a manner that no gap is formed between the first block 11 and the gasket 13, and the gasket 13 can be brought into contact with the second block 12 in a manner that no gap is formed between the second block 12 and the gasket 13. As a result, it is possible to suppress leakage of the coating liquid from between the first block 11 and the gasket 13, or between the second block 12 and the gasket 13. In addition, when the elastic modulus of the gasket 13 is below the above upper limit, even if the gasket 13 is slightly bent during storage or a minute scratch is formed on the gasket 13, the gasket 13 can be sandwiched between the first block 11 and the second block 12 following the first block 11 and the second block 12. On the other hand, when the elastic modulus of the gasket 13 is above the above lower limit, when the gasket 13 is sandwiched between the first block 11 and the second block 12, excessive deformation of the gasket 13 can be suppressed.

[0092] The gasket 13 is preferably formed of polyethylene terephthalate. When the gasket 13 is formed of polyethylene terephthalate, the elastic modulus of the gasket 13 can be set within the above range. In addition, when the gasket 13 is formed of polyethylene terephthalate, the gasket 13 can be easily processed.

[0093] 4. Uniformity of the film

[0094] By applying the above-mentioned coating liquid to the substrate S using the above-mentioned slot die D and drying it, a film F having a uniform thickness of the coating film C in the entire width direction of the substrate S can be produced.

[0095] In the obtained film F, in the width direction of the substrate S, the difference between the thickness of the central portion of the film C and the thickness of the end portion of the film C is, for example, 2.5 μm or less, preferably 2.0 μm or less, more preferably 1.5 μm or less, more preferably 1.0 μm or less, and more preferably 0.5 μm or less. It should be noted that the lower limit of the difference between the thickness of the central portion of the film C and the thickness of the end portion of the film C is not limited. The difference between the thickness of the central portion of the film C and the thickness of the end portion of the film C may be 0 μm.

[0096] 5. Effect

[0097] According to the method for producing the film F, the thickness of the spacer 13 of the slot die D is adjusted to be 30 μm or more and 100 μm or less.

[0098] Therefore, a wide (width of 1600 mm or more) and thin (thickness of 30 μm or less) film C can be uniformly formed on the substrate S.

[0099] Specifically, when the viscosity of the coating liquid is 100 mPa or less, the difference between the thickness of the center portion of the film C and the thickness of the end portions of the film C in the width direction of the substrate S can be set to 2.5 μm or less.

[0100] Example

[0101] Next, the present invention is described based on examples and comparative examples. The present invention is not limited by the following examples. In addition, the specific numerical values ​​of the physical property values, parameters, etc. used in the following description can be replaced by the upper limit values ​​(numerical values ​​defined in the form of "below", "less than") or lower limit values ​​(numerical values ​​defined in the form of "above", "greater than") of the physical property values, parameters, etc. corresponding to them recorded in the above-mentioned "Specific Implementation Methods" part.

[0102] 1. Preparation of coating liquid

[0103] The following materials were mixed in toluene to obtain a coating liquid. The solid content of the coating liquid was 42% by mass and the viscosity of the coating liquid was 6 mPa·s.

[0104] Multifunctional oligomers:

[0105] NK oligomer UA-53H-80BK (manufactured by Shin-Nakamura Chemical Industry Co., Ltd.) 50 parts by mass

[0106] Multifunctional monomers:

[0107] Viscoat #300 (manufactured by Osaka Organic Chemical Industry Co., Ltd.) 50 parts by mass

[0108] Hydroxyl monomer:

[0109] 4-Hydroxybutyl acrylate (manufactured by Osaka Organic Chemical Industry Co., Ltd.) 20 parts by mass

[0110] Photopolymerization initiator:

[0111] Omnirad 907 (manufactured by IGM Resin Co., Ltd.) 5 parts by mass

[0112] Surface tension modifier

[0113] GRANDIC PC4100 (manufactured by DIC Corporation) 1 part by mass

[0114] Silica particles

[0115] Techpolymer SSX-103DXE (manufactured by Sekisui Chemicals Co., Ltd.) 0.5 parts by mass

[0116] Tackifier

[0117] Smecton-SAN solution (manufactured by Nitto Denko Corporation) 1.5 parts by mass

[0118] 2. Membrane Fabrication

[0119] use Figure 3 The coating liquid was applied to a substrate (material: acrylic film) using the slot die (block height: 76 mm) shown in Table 1 to Table 3, and dried at 95°C for 1 minute to obtain films of various embodiments and comparative examples having a coating of acrylic urethane resin on the substrate.

[0120] The thickness of the film obtained was measured at five locations in the width direction of the substrate (center, one end, the other end, between one end and the center, and between the other end and the center), and the difference between the maximum thickness and the minimum thickness was calculated. The results are shown in Table 1.

[0121] In addition, the appearance of the film was evaluated based on the following criteria. The results are shown in Tables 1 to 3.

[0122] <Appearance Evaluation Criteria>

[0123] A: There is no appearance defect at all when inspected with the naked eye.

[0124] B: Although a small amount of unevenness was observed in visual inspection, the product can be used as a product.

[0125] C: Appearance defects were observed during visual inspection, but the product can be used.

[0126] D: The entire surface is defective in appearance and cannot be used as a product.

[0127] [Table 1]

[0128]

[0129] [Table 2]

[0130]

[0131] [Table 3]

[0132]

[0133] It should be noted that the above invention is provided as an exemplary embodiment of the present invention, but it is only an example and is not to be interpreted as limiting. It is clear to those skilled in the art that the modified examples of the present invention are included in the attached claims.

[0134] Industrial Applicability

[0135] The film production method of the present invention can be used for the production of a film.

Claims

1. A method for producing a film, which is a method for forming a film having a width of 1600 mm or more and a thickness of 30 μm or less on a substrate using a slot die, The method includes: A coating step of applying a coating liquid to a substrate; and a drying step of drying the coating liquid applied to the substrate, The thickness of the shim of the slot die is 20 μm or more and 100 μm or less.

2. The method for producing a film according to claim 1, wherein: The slot die includes a first block, a second block, and the gasket, wherein the second block is arranged on the downstream side of the first block in the conveying direction of the substrate and forms a slot with the first block, and the gasket is arranged between the first block and the second block. The second block has: Main body, and a protrusion that protrudes from an end surface on the downstream side of the main body toward the downstream side in the ejection direction of the coating liquid, The protrusion amount of the protrusion is 10 μm or less.

3. The method for producing a film according to claim 1, wherein: The slot die includes a first block, a second block, and the gasket, wherein the second block is arranged on the downstream side of the first block in the conveying direction of the substrate and forms a slot with the first block, and the gasket is arranged between the first block and the second block. The second block has an inclined surface that is inclined in a direction away from the first block as it moves from a downstream end of the second block in a direction in which the coating liquid is ejected toward an upstream end of the second block in the ejection direction. An obtuse angle formed by a discharge direction of the coating liquid and the inclined surface is greater than or equal to 110° and less than or equal to 170°.

4. The method for producing a film according to claim 1, wherein: The conveyance speed of the substrate is 15 m / min or more and 30 m / min or less.

5. The method for producing a film according to claim 1, wherein: The coating liquid has a solid content concentration of 10% by mass or more and 50% by mass or less.

6. The method for producing a film according to claim 1, wherein: The coating liquid contains a multifunctional oligomer and a trifunctional monomer. The ratio of the polyfunctional oligomer in the coating liquid is 20% by mass or more and 70% by mass or less, The ratio of the trifunctional monomer in the coating liquid is 20 mass % or more and 70 mass % or less.

7. The method for producing a film according to claim 1, wherein: The elastic modulus of the gasket is 1500 MPa or more and 6000 MPa or less.

8. The method for producing a film according to claim 1, wherein: The gasket is formed of polyethylene terephthalate.

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